[exim-cvs] TLS: preload configuration items

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Συντάκτης: Exim Git Commits Mailing List
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Προς: exim-cvs
Αντικείμενο: [exim-cvs] TLS: preload configuration items
Gitweb: https://git.exim.org/exim.git/commitdiff/6a9cf7f890226aa085842cd3d94b13e78ea31637
Commit:     6a9cf7f890226aa085842cd3d94b13e78ea31637
Parent:     dcc5e2cbb4a253eea54c12320e54fb5d85d64e5f
Author:     Jeremy Harris <jgh146exb@???>
AuthorDate: Sat Oct 3 20:59:15 2020 +0100
Committer:  Jeremy Harris <jgh146exb@???>
CommitDate: Sun Oct 4 00:14:30 2020 +0100


    TLS: preload configuration items
---
 doc/doc-docbook/spec.xfpt        |  116 +-
 doc/doc-txt/NewStuff             |    4 +
 src/OS/os.h-Linux                |    3 +
 src/src/daemon.c                 |   31 +-
 src/src/exim.h                   |    4 +
 src/src/functions.h              |    4 +-
 src/src/globals.c                |   48 +-
 src/src/globals.h                |    2 +
 src/src/queue.c                  |   13 +
 src/src/smtp_in.c                |    4 +-
 src/src/smtp_out.c               |    2 +-
 src/src/tls-gnu.c                | 1247 +++++++++++++-------
 src/src/tls-openssl.c            | 2410 +++++++++++++++++++++++---------------
 src/src/tls.c                    |  161 ++-
 src/src/transports/smtp.c        |   65 +-
 src/src/transports/smtp.h        |   23 +
 test/confs/1102                  |   27 +
 test/confs/1103                  |   43 +
 test/confs/2025                  |    7 +-
 test/confs/2100                  |    8 +-
 test/confs/2113                  |    1 -
 test/confs/4060                  |    6 +-
 test/log/1103                    |    9 +
 test/runtest                     |   26 +
 test/scripts/1100-Basic-TLS/1101 |    3 +-
 test/scripts/1100-Basic-TLS/1102 |   51 +
 test/scripts/1100-Basic-TLS/1103 |   21 +
 27 files changed, 2834 insertions(+), 1505 deletions(-)


diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 2e4df80..d0c3e78 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -29271,6 +29271,61 @@ There is no current way to staple a proof for a client certificate.
.endd


+.new
+.section "Caching of static server configuration items" "SECTserverTLScache"
+.cindex certificate caching
+.cindex privatekey caching
+.cindex crl caching
+.cindex ocsp caching
+.cindex ciphers caching
+.cindex "CA bundle" caching
+.cindex "certificate authorities" caching
+.cindex tls_certificate caching
+.cindex tls_privatekey caching
+.cindex tls_crl caching
+.cindex tls_ocsp_file caching
+.cindex tls_require_ciphers caching
+.cindex tls_verify_certificate caching
+.cindex caching certificate
+.cindex caching privatekey
+.cindex caching crl
+.cindex caching ocsp
+.cindex caching ciphers
+.cindex caching "certificate authorities
+If any of the main configuration options &%tls_certificate%&, &%tls_privatekey%&,
+&%tls_crl%& and &%tls_ocsp_file%& have values with no
+expandable elements,
+then the associated information is loaded at daemon startup.
+It is made available
+to child processes forked for handling received SMTP connections.
+
+This caching is currently only supported under Linux.
+
+If caching is not possible, for example if an item has to be dependent
+on the peer host so contains a &$sender_host_name$& expansion, the load
+of the associated information is done at the startup of the TLS connection.
+
+The cache is invalidated and reloaded after any changes to the directories
+containing files specified by these options.
+
+The information specified by the main option &%tls_verify_certificates%&
+is similarly cached so long as it specifies files explicitly
+or (under GnuTLS) is the string &"system,cache"&.
+The latter case is not automatically invaludated;
+it is the operator's responsibility to arrange for a daemon restart
+any time the system certificate authority bundle is updated.
+A HUP signal is sufficient for this.
+The value &"system"& results in no caching under GnuTLS.
+
+The macro _HAVE_TLS_CA_CACHE will be defined if the suffix for "system"
+is acceptable in configurations for the Exim executavble.
+
+Caching of the system Certificate Authorities bundle can
+save siginificant time and processing on every TLS connection
+accepted by Exim.
+.wen
+
+


.section "Configuring an Exim client to use TLS" "SECTclientTLS"
@@ -29311,7 +29366,10 @@ unencrypted.

The &%tls_certificate%& and &%tls_privatekey%& options of the &(smtp)&
transport provide the client with a certificate, which is passed to the server
-if it requests it. If the server is Exim, it will request a certificate only if
+if it requests it.
+This is an optional thing for TLS connections, although either end
+may insist on it.
+If the server is Exim, it will request a certificate only if
&%tls_verify_hosts%& or &%tls_try_verify_hosts%& matches the client.

&*Note*&: Do not use a certificate which has the OCSP-must-staple extension,
@@ -29391,6 +29449,62 @@ outgoing connection.



+.new
+.section "Caching of static client configuration items" "SECTclientTLScache"
+.cindex certificate caching
+.cindex privatekey caching
+.cindex crl caching
+.cindex ciphers caching
+.cindex "CA bundle" caching
+.cindex "certificate authorities" caching
+.cindex tls_certificate caching
+.cindex tls_privatekey caching
+.cindex tls_crl caching
+.cindex tls_require_ciphers caching
+.cindex tls_verify_certificate caching
+.cindex caching certificate
+.cindex caching privatekey
+.cindex caching crl
+.cindex caching ciphers
+.cindex caching "certificate authorities
+If any of the transport configuration options &%tls_certificate%&, &%tls_privatekey%&
+and &%tls_crl%& have values with no
+expandable elements,
+then the associated information is loaded per smtp transport
+at daemon startup, at the start of a queue run, or on a
+command-line specified message delivery.
+It is made available
+to child processes forked for handling making SMTP connections.
+
+This caching is currently only supported under Linux.
+
+If caching is not possible, the load
+of the associated information is done at the startup of the TLS connection.
+
+The cache is invalidated in the daemon
+and reloaded after any changes to the directories
+containing files specified by these options.
+
+The information specified by the main option &%tls_verify_certificates%&
+is similarly cached so long as it specifies files explicitly
+or (under GnuTLS) is the string &"system,cache"&.
+The latter case is not automatically invaludated;
+it is the operator's responsibility to arrange for a daemon restart
+any time the system certificate authority bundle is updated.
+A HUP signal is sufficient for this.
+The value &"system"& results in no caching under GnuTLS.
+
+The macro _HAVE_TLS_CA_CACHE will be defined if the suffix for "system"
+is acceptable in configurations for the Exim executavble.
+
+Caching of the system Certificate Authorities bundle can
+save siginificant time and processing on every TLS connection
+initiated by Exim.
+.wen
+
+
+
+
.section "Use of TLS Server Name Indication" "SECTtlssni"
.cindex "TLS" "Server Name Indication"
.cindex "TLS" SNI
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index abbcf4c..acbbc15 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -38,6 +38,10 @@ Version 4.95

10. A command-line option to have a daemon not create a notifier socket.

+11. Faster TLS startup.  When various configuration options contain no
+    expandable elements, the information can be preloaded and cached rather
+    than the provious behaviour of always loading at startup time for every
+    connection.  This helps particularly for the CA bundle.


Version 4.94
------------
diff --git a/src/OS/os.h-Linux b/src/OS/os.h-Linux
index 4a14134..2fa1b0b 100644
--- a/src/OS/os.h-Linux
+++ b/src/OS/os.h-Linux
@@ -91,5 +91,8 @@ then change the 0 to 1 in the next block. */
/* "Abstract" Unix-socket names */
#define EXIM_HAVE_ABSTRACT_UNIX_SOCKETS

+/* inotify(7) etc syscalls */
+#define EXIM_HAVE_INOTIFY
+

/* End */
diff --git a/src/src/daemon.c b/src/src/daemon.c
index f56e36a..4e90799 100644
--- a/src/src/daemon.c
+++ b/src/src/daemon.c
@@ -963,6 +963,11 @@ daemon_die(void)
{
int pid;

+#ifndef DISABLE_TLS
+if (tls_watch_fd >= 0)
+ { close(tls_watch_fd); tls_watch_fd = -1; }
+#endif
+
if (daemon_notifier_fd >= 0)
{
close(daemon_notifier_fd);
@@ -2039,6 +2044,9 @@ malware_init();
#ifdef SUPPORT_SPF
spf_init();
#endif
+#ifndef DISABLE_TLS
+tls_daemon_init();
+#endif

 /* Close the log so it can be renamed and moved. In the few cases below where
 this long-running process writes to the log (always exceptional conditions), it
@@ -2277,8 +2285,18 @@ for (;;)
     fd_set select_listen;


     FD_ZERO(&select_listen);
+#ifndef DISABLE_TLS
+    if (tls_watch_fd >= 0)
+      {
+      FD_SET(tls_watch_fd, &select_listen);
+      if (tls_watch_fd > max_socket) max_socket = tls_watch_fd;
+      }
+#endif
     if (daemon_notifier_fd >= 0)
+      {
       FD_SET(daemon_notifier_fd, &select_listen);
+      if (daemon_notifier_fd > max_socket) max_socket = daemon_notifier_fd;
+      }
     for (int sk = 0; sk < listen_socket_count; sk++)
       {
       FD_SET(listen_sockets[sk], &select_listen);
@@ -2321,8 +2339,8 @@ for (;;)
     errno = select_errno;


 #ifndef DISABLE_TLS
-    /* Create or rotate any required keys */
-    tls_daemon_init();
+    /* Create or rotate any required keys; handle (delayed) filewatch event */
+    tls_daemon_tick();
 #endif


     /* Loop for all the sockets that are currently ready to go. If select
@@ -2335,6 +2353,15 @@ for (;;)


       if (!select_failed)
     {
+#if defined(EXIM_HAVE_INOTIFY) && !defined(DISABLE_TLS)
+    if (tls_watch_fd >= 0 && FD_ISSET(tls_watch_fd, &select_listen))
+      {
+      FD_CLR(tls_watch_fd, &select_listen);
+          tls_watch_trigger_time = time(NULL);    /* Set up delayed event */
+      (void) read(tls_watch_fd, big_buffer, big_buffer_size);
+      break;    /* to top of daemon loop */
+      }
+#endif
     if (  daemon_notifier_fd >= 0
        && FD_ISSET(daemon_notifier_fd, &select_listen))
       {
diff --git a/src/src/exim.h b/src/src/exim.h
index 1ddba18..6669e80 100644
--- a/src/src/exim.h
+++ b/src/src/exim.h
@@ -87,6 +87,10 @@ making unique names. */
 # include <limits.h>
 #endif


+#ifdef EXIM_HAVE_INOTIFY
+# include <sys/inotify.h>
+#endif
+
/* C99 integer types, figure out how to undo this if needed for older systems */

 #include <inttypes.h>
diff --git a/src/src/functions.h b/src/src/functions.h
index cc9137c..c698519 100644
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -53,10 +53,12 @@ extern uschar * tls_cert_fprt_sha256(void *);
 extern void    tls_clean_env(void);
 extern BOOL    tls_client_start(client_conn_ctx *, smtp_connect_args *,
           void *, tls_support *, uschar **);
+extern void    tls_client_creds_reload(BOOL);


 extern void    tls_close(void *, int);
 extern BOOL    tls_could_read(void);
 extern void    tls_daemon_init(void);
+extern void    tls_daemon_tick(void);
 extern BOOL    tls_dropprivs_validate_require_cipher(BOOL);
 extern BOOL    tls_export_cert(uschar *, size_t, void *);
 extern int     tls_feof(void);
@@ -67,7 +69,7 @@ extern uschar *tls_getbuf(unsigned *);
 extern void    tls_get_cache(void);
 extern BOOL    tls_import_cert(const uschar *, void **);
 extern int     tls_read(void *, uschar *, size_t);
-extern int     tls_server_start(const uschar *, uschar **);
+extern int     tls_server_start(uschar **);
 extern BOOL    tls_smtp_buffered(void);
 extern int     tls_ungetc(int);
 extern int     tls_write(void *, const uschar *, size_t, BOOL);
diff --git a/src/src/globals.c b/src/src/globals.c
index fb0abb8..240c2eb 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -143,6 +143,8 @@ uschar *tls_resumption_hosts   = NULL;
 uschar *tls_try_verify_hosts   = NULL;
 uschar *tls_verify_certificates= US"system";
 uschar *tls_verify_hosts       = NULL;
+int     tls_watch_fd           = -1;
+time_t  tls_watch_trigger_time = (time_t)0;
 #else    /*DISABLE_TLS*/
 uschar *tls_advertise_hosts    = NULL;
 #endif
@@ -1560,60 +1562,16 @@ struct timeval timestamp_startup;
 transport_instance  *transports = NULL;


 transport_instance  transport_defaults = {
-    .next =            NULL,
-    .name =            NULL,
-    .info =            NULL,
-    .options_block =        NULL,
-    .driver_name =        NULL,
-    .setup =            NULL,
+    /* All non-mentioned elements zero/NULL/FALSE */
     .batch_max =        1,
-    .batch_id =            NULL,
-    .home_dir =            NULL,
-    .current_dir =        NULL,
-    .expand_multi_domain =    NULL,
     .multi_domain =        TRUE,
-    .overrides_hosts =        FALSE,
     .max_addresses =        100,
     .connection_max_messages =    500,
-    .deliver_as_creator =    FALSE,
-    .disable_logging =        FALSE,
-    .initgroups =        FALSE,
-    .uid_set =            FALSE,
-    .gid_set =            FALSE,
     .uid =            (uid_t)(-1),
     .gid =            (gid_t)(-1),
-    .expand_uid =        NULL,
-    .expand_gid =        NULL,
-    .warn_message =        NULL,
-    .shadow =            NULL,
-    .shadow_condition =        NULL,
-    .filter_command =        NULL,
-    .add_headers =        NULL,
-    .remove_headers =        NULL,
-    .return_path =        NULL,
-    .debug_string =        NULL,
-    .max_parallel =        NULL,
-    .message_size_limit =    NULL,
-    .headers_rewrite =        NULL,
-    .rewrite_rules =        NULL,
-    .rewrite_existflags =    0,
     .filter_timeout =        300,
-    .body_only =        FALSE,
-    .delivery_date_add =    FALSE,
-    .envelope_to_add =        FALSE,
-    .headers_only =        FALSE,
-    .rcpt_include_affixes =    FALSE,
-    .return_path_add =        FALSE,
-    .return_output =        FALSE,
-    .return_fail_output =    FALSE,
-    .log_output =        FALSE,
-    .log_fail_output =        FALSE,
-    .log_defer_output =        FALSE,
     .retry_use_local_part =    TRUE_UNSET,    /* retry_use_local_part: BOOL, but set neither
                          1 nor 0 so can detect unset */
-#ifndef DISABLE_EVENT
-   .event_action =        NULL
-#endif
 };


 int     transport_count;
diff --git a/src/src/globals.h b/src/src/globals.h
index 954a0a3..8fbb141 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -140,6 +140,8 @@ extern uschar *tls_resumption_hosts;   /* TLS session resumption */
 extern uschar *tls_try_verify_hosts;   /* Optional client verification */
 extern uschar *tls_verify_certificates;/* Path for certificates to check */
 extern uschar *tls_verify_hosts;       /* Mandatory client verification */
+extern int     tls_watch_fd;           /* for inotify of creds files */
+extern time_t  tls_watch_trigger_time; /* non-0: triggered */
 #endif
 extern uschar *tls_advertise_hosts;    /* host for which TLS is advertised */


diff --git a/src/src/queue.c b/src/src/queue.c
index 6748afd..4c93c1d 100644
--- a/src/src/queue.c
+++ b/src/src/queue.c
@@ -26,6 +26,9 @@ Michael Haardt. */
#define LOG2_MAXNODES 32


+#ifndef DISABLE_TLS
+static BOOL queue_tls_init = FALSE;
+#endif

 /*************************************************
 *  Helper sort function for queue_get_spool_list *
@@ -648,6 +651,16 @@ for (int i = queue_run_in_order ? -1 : 0;
     report_time_since(&timestamp_startup, US"queue msg selected");
 #endif


+#ifndef DISABLE_TLS
+    if (!queue_tls_init)
+      {
+      queue_tls_init = TRUE;
+      /* Preload TLS library info for smtp transports.  Once, and only if we
+      have a delivery to do. */
+      tls_client_creds_reload(FALSE);
+      }
+#endif
+
 single_item_retry:
     if ((pid = exim_fork(US"qrun-delivery")) == 0)
       {
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index aa1d5b0..c0b6b2a 100644
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -2934,7 +2934,7 @@ if (check_proxy_protocol_host())
 #ifndef DISABLE_TLS
   if (tls_in.on_connect)
     {
-    if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
+    if (tls_server_start(&user_msg) != OK)
       return smtp_log_tls_fail(user_msg);
     cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
     }
@@ -5490,7 +5490,7 @@ while (done <= 0)
       STARTTLS that don't add to the nonmail command count. */


       s = NULL;
-      if ((rc = tls_server_start(tls_require_ciphers, &s)) == OK)
+      if ((rc = tls_server_start(&s)) == OK)
     {
     if (!tls_remember_esmtp)
       fl.helo_seen = fl.esmtp = fl.auth_advertised = f.smtp_in_pipelining_advertised = FALSE;
diff --git a/src/src/smtp_out.c b/src/src/smtp_out.c
index c4c4096..911dd53 100644
--- a/src/src/smtp_out.c
+++ b/src/src/smtp_out.c
@@ -609,7 +609,7 @@ if (format)
       while (!isspace(*p)) p++;
       while (isspace(*p)) p++;
       }
-    while (*p != 0) *p++ = '*';
+    while (*p) *p++ = '*';
     }


HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> %s\n", big_buffer);
diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index 03af7d7..f5c6a8b 100644
--- a/src/src/tls-gnu.c
+++ b/src/src/tls-gnu.c
@@ -145,6 +145,9 @@ builtin_macro_create(US"_HAVE_TLS_OCSP");
# ifdef SUPPORT_SRV_OCSP_STACK
builtin_macro_create(US"_HAVE_TLS_OCSP_LIST");
# endif
+#ifdef EXIM_HAVE_INOTIFY
+builtin_macro_create(US"_HAVE_TLS_CA_CACHE");
+# endif
}
#else

@@ -178,8 +181,11 @@ Not handled here: global tlsp->tls_channelbinding.

 typedef struct exim_gnutls_state {
   gnutls_session_t    session;
-  gnutls_certificate_credentials_t x509_cred;
-  gnutls_priority_t    priority_cache;
+
+  exim_tlslib_state    lib_state;
+#define x509_cred        libdata0
+#define pri_cache        libdata1
+
   enum peer_verify_requirement verify_requirement;
   int            fd_in;
   int            fd_out;
@@ -245,7 +251,11 @@ second connection.
 XXX But see gnutls_session_get_ptr()
 */


-static exim_gnutls_state_st state_server;
+static exim_gnutls_state_st state_server = {
+  /* all elements not explicitly intialised here get 0/NULL/FALSE */
+  .fd_in =        -1,
+  .fd_out =        -1,
+};


#ifndef GNUTLS_AUTO_DHPARAMS
/* dh_params are initialised once within the lifetime of a process using TLS;
@@ -298,7 +308,7 @@ before, for now. */
# define EXIM_SERVER_DH_BITS_PRE2_12 1024
#endif

-#define expand_check_tlsvar(Varname, errstr) \
+#define Expand_check_tlsvar(Varname, errstr) \
expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr)

#if GNUTLS_VERSION_NUMBER >= 0x020c00
@@ -335,22 +345,114 @@ tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when,
#endif


+/* ------------------------------------------------------------------------ */
+/* Initialisation */
+
+#ifndef DISABLE_OCSP
+
+static BOOL
+tls_is_buggy_ocsp(void)
+{
+const uschar * s;
+uschar maj, mid, mic;
+
+s = CUS gnutls_check_version(NULL);
+maj = atoi(CCS s);
+if (maj == 3)
+  {
+  while (*s && *s != '.') s++;
+  mid = atoi(CCS ++s);
+  if (mid <= 2)
+    return TRUE;
+  else if (mid >= 5)
+    return FALSE;
+  else
+    {
+    while (*s && *s != '.') s++;
+    mic = atoi(CCS ++s);
+    return mic <= (mid == 3 ? 16 : 3);
+    }
+  }
+return FALSE;
+}
+
+#endif
+
+
+static void
+tls_g_init(void)
+{
+DEBUG(D_tls) debug_printf("GnuTLS global init required\n");
+
+#if defined(HAVE_GNUTLS_PKCS11) && !defined(GNUTLS_AUTO_PKCS11_MANUAL)
+/* By default, gnutls_global_init will init PKCS11 support in auto mode,
+which loads modules from a config file, which sounds good and may be wanted
+by some sysadmin, but also means in common configurations that GNOME keyring
+environment variables are used and so breaks for users calling mailq.
+To prevent this, we init PKCS11 first, which is the documented approach. */
+
+if (!gnutls_allow_auto_pkcs11)
+  if ((rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL)))
+    return tls_error_gnu(US"gnutls_pkcs11_init", rc, host, errstr);
+#endif
+
+#ifndef GNUTLS_AUTO_GLOBAL_INIT
+if ((rc = gnutls_global_init()))
+  return tls_error_gnu(US"gnutls_global_init", rc, host, errstr);
+#endif
+
+#if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
+DEBUG(D_tls)
+  {
+  gnutls_global_set_log_function(exim_gnutls_logger_cb);
+  /* arbitrarily chosen level; bump up to 9 for more */
+  gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL);
+  }
+#endif
+
+#ifndef DISABLE_OCSP
+if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp()))
+  log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version");
+#endif
+
+exim_gnutls_base_init_done = TRUE;
+}
+
+
+
+/* Daemon-call before each connection.  Nothing to do for GnuTLS. */
+
+static void
+tls_per_lib_daemon_tick(void)
+{
+}
+
 /* Daemon one-time initialisation */
-void
-tls_daemon_init(void)
+
+static void
+tls_per_lib_daemon_init(void)
 {
+static BOOL once = FALSE;
+
+if (!exim_gnutls_base_init_done)
+  tls_g_init();
+
+if (!once)
+  {
+  once = TRUE;
+
 #ifdef EXIM_HAVE_TLS_RESUME
-/* We are dependent on the GnuTLS implementation of the Session Ticket
-encryption; both the strength and the key rotation period.  We hope that
-the strength at least matches that of the ciphersuite (but GnuTLS does not
-document this). */
+  /* We are dependent on the GnuTLS implementation of the Session Ticket
+  encryption; both the strength and the key rotation period.  We hope that
+  the strength at least matches that of the ciphersuite (but GnuTLS does not
+  document this). */


-static BOOL once = FALSE;
-if (once) return;
-once = TRUE;
-gnutls_session_ticket_key_generate(&server_sessticket_key);    /* >= 2.10.0 */
-if (f.running_in_test_harness) ssl_session_timeout = 6;
+  gnutls_session_ticket_key_generate(&server_sessticket_key);    /* >= 2.10.0 */
+  if (f.running_in_test_harness) ssl_session_timeout = 6;
 #endif
+
+  tls_daemon_creds_reload();
+  }
 }


/* ------------------------------------------------------------------------ */
@@ -598,7 +700,7 @@ uschar *exp_tls_dhparam;
BOOL use_file_in_spool = FALSE;
host_item *host = NULL; /* dummy for macros */

-DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n");
+DEBUG(D_tls) debug_printf("Initialising GnuTLS server params\n");

 if ((rc = gnutls_dh_params_init(&dh_server_params)))
   return tls_error_gnu(US"gnutls_dh_params_init", rc, host, errstr);
@@ -616,7 +718,7 @@ else if (Ustrcmp(exp_tls_dhparam, "historic") == 0)
   use_file_in_spool = TRUE;
 else if (Ustrcmp(exp_tls_dhparam, "none") == 0)
   {
-  DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
+  DEBUG(D_tls) debug_printf("Requested no DH parameters\n");
   return OK;
   }
 else if (exp_tls_dhparam[0] != '/')
@@ -643,12 +745,12 @@ different filename and ensure we have sufficient bits. */
 if (!(dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL)))
   return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr);
 DEBUG(D_tls)
-  debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n",
+  debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits\n",
       dh_bits);
 #else
 dh_bits = EXIM_SERVER_DH_BITS_PRE2_12;
 DEBUG(D_tls)
-  debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits.\n",
+  debug_printf("GnuTLS lacks gnutls_sec_param_to_pk_bits(), using %d bits\n",
       dh_bits);
 #endif


@@ -656,7 +758,7 @@ DEBUG(D_tls)
 if (dh_bits > tls_dh_max_bits)
   {
   DEBUG(D_tls)
-    debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n",
+    debug_printf("tls_dh_max_bits clamping override, using %d bits instead\n",
         tls_dh_max_bits);
   dh_bits = tls_dh_max_bits;
   }
@@ -884,7 +986,8 @@ if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err;


 where = US"installing selfsign cert";
                     /* Since: 2.4.0 */
-if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey)))
+if ((rc = gnutls_certificate_set_x509_key(state->lib_state.x509_cred,
+    &cert, 1, pkey)))
   goto err;


rc = OK;
@@ -911,10 +1014,10 @@ Return:

 static int
 tls_add_certfile(exim_gnutls_state_st * state, const host_item * host,
-  uschar * certfile, uschar * keyfile, uschar ** errstr)
+  const uschar * certfile, const uschar * keyfile, uschar ** errstr)
 {
-int rc = gnutls_certificate_set_x509_key_file(state->x509_cred,
-    CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM);
+int rc = gnutls_certificate_set_x509_key_file(state->lib_state.x509_cred,
+    CCS certfile, CCS keyfile, GNUTLS_X509_FMT_PEM);
 if (rc < 0)
   return tls_error_gnu(
     string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile),
@@ -1024,50 +1127,508 @@ tls_in.ocsp = exim_testharness_disable_ocsp_validity_check
 #else
 tls_in.ocsp = OCSP_VFY_NOT_TRIED;
 #endif
-return 0;
+return 0;
+}
+
+/* Callback for handshake messages, on server */
+static int
+tls_server_hook_cb(gnutls_session_t sess, u_int htype, unsigned when,
+  unsigned incoming, const gnutls_datum_t * msg)
+{
+/* debug_printf("%s: htype %u\n", __FUNCTION__, htype); */
+switch (htype)
+  {
+# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
+  case GNUTLS_HANDSHAKE_CLIENT_HELLO:
+    return tls_server_clienthello_cb(sess, htype, when, incoming, msg);
+  case GNUTLS_HANDSHAKE_CERTIFICATE_PKT:
+    return tls_server_servercerts_cb(sess, htype, when, incoming, msg);
+# endif
+  case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS:
+    return tls_server_certstatus_cb(sess, htype, when, incoming, msg);
+# ifdef EXIM_HAVE_TLS_RESUME
+  case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET:
+    return tls_server_ticket_cb(sess, htype, when, incoming, msg);
+# endif
+  default:
+    return 0;
+  }
+}
+#endif
+
+
+#if !defined(DISABLE_OCSP) && defined(SUPPORT_GNUTLS_EXT_RAW_PARSE)
+static void
+tls_server_testharness_ocsp_fiddle(void)
+{
+extern char ** environ;
+if (environ) for (uschar ** p = USS environ; *p; p++)
+  if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
+    {
+    DEBUG(D_tls) debug_printf("Permitting known bad OCSP response\n");
+    exim_testharness_disable_ocsp_validity_check = TRUE;
+    }
+}
+#endif
+
+/**************************************************
+* One-time init credentials for server and client *
+**************************************************/
+
+static void
+creds_basic_init(gnutls_certificate_credentials_t x509_cred, BOOL server)
+{
+#ifdef SUPPORT_SRV_OCSP_STACK
+gnutls_certificate_set_flags(x509_cred, GNUTLS_CERTIFICATE_API_V2);
+
+# if !defined(DISABLE_OCSP) && defined(SUPPORT_GNUTLS_EXT_RAW_PARSE)
+if (server && tls_ocsp_file)
+  {
+  if (f.running_in_test_harness)
+    tls_server_testharness_ocsp_fiddle();
+
+  if (exim_testharness_disable_ocsp_validity_check)
+    gnutls_certificate_set_flags(x509_cred,
+      GNUTLS_CERTIFICATE_API_V2 | GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK);
+  }
+# endif
+#endif
+DEBUG(D_tls)
+  debug_printf("TLS: basic cred init, %s\n", server ? "server" : "client");
+}
+
+static int
+creds_load_server_certs(exim_gnutls_state_st * state, const uschar * cert,
+  const uschar * pkey, const uschar * ocsp, uschar ** errstr)
+{
+const uschar * clist = cert;
+const uschar * klist = pkey;
+const uschar * olist;
+int csep = 0, ksep = 0, osep = 0, cnt = 0, rc;
+uschar * cfile, * kfile, * ofile;
+#ifndef DISABLE_OCSP
+# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
+gnutls_x509_crt_fmt_t ocsp_fmt = GNUTLS_X509_FMT_DER;
+# endif
+
+if (!expand_check(ocsp, US"tls_ocsp_file", &ofile, errstr))
+  return DEFER;
+olist = ofile;
+#endif
+
+while (cfile = string_nextinlist(&clist, &csep, NULL, 0))
+
+  if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0)))
+    return tls_error(US"cert/key setup: out of keys", NULL, NULL, errstr);
+  else if ((rc = tls_add_certfile(state, NULL, cfile, kfile, errstr)) > 0)
+    return rc;
+  else
+    {
+    int gnutls_cert_index = -rc;
+    DEBUG(D_tls) debug_printf("TLS: cert/key %d %s registered\n",
+                  gnutls_cert_index, cfile);
+
+#ifndef DISABLE_OCSP
+    if (ocsp)
+      {
+      /* Set the OCSP stapling server info */
+      if (gnutls_buggy_ocsp)
+    {
+    DEBUG(D_tls)
+      debug_printf("GnuTLS library is buggy for OCSP; avoiding\n");
+    }
+      else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0)))
+    {
+    DEBUG(D_tls) debug_printf("OCSP response file %d  = %s\n",
+                  gnutls_cert_index, ofile);
+# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
+    if (Ustrncmp(ofile, US"PEM ", 4) == 0)
+      {
+      ocsp_fmt = GNUTLS_X509_FMT_PEM;
+      ofile += 4;
+      }
+    else if (Ustrncmp(ofile, US"DER ", 4) == 0)
+      {
+      ocsp_fmt = GNUTLS_X509_FMT_DER;
+      ofile += 4;
+      }
+
+    if  ((rc = gnutls_certificate_set_ocsp_status_request_file2(
+          state->lib_state.x509_cred, CCS ofile, gnutls_cert_index,
+          ocsp_fmt)) < 0)
+      return tls_error_gnu(
+          US"gnutls_certificate_set_ocsp_status_request_file2",
+          rc, NULL, errstr);
+    DEBUG(D_tls)
+      debug_printf(" %d response%s loaded\n", rc, rc>1 ? "s":"");
+
+    /* Arrange callbacks for OCSP request observability */
+
+    if (state->session)
+      gnutls_handshake_set_hook_function(state->session,
+        GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb);
+    else
+      state->lib_state.ocsp_hook = TRUE;
+
+
+# else
+#  if defined(SUPPORT_SRV_OCSP_STACK)
+    if ((rc = gnutls_certificate_set_ocsp_status_request_function2(
+             state->lib_state.x509_cred, gnutls_cert_index,
+             server_ocsp_stapling_cb, ofile)))
+        return tls_error_gnu(
+          US"gnutls_certificate_set_ocsp_status_request_function2",
+          rc, NULL, errstr);
+    else
+#  endif
+      {
+      if (cnt++ > 0)
+        {
+        DEBUG(D_tls)
+          debug_printf("oops; multiple OCSP files not supported\n");
+        break;
+        }
+      gnutls_certificate_set_ocsp_status_request_function(
+        state->lib_state.x509_cred, server_ocsp_stapling_cb, ofile);
+      }
+# endif    /* SUPPORT_GNUTLS_EXT_RAW_PARSE */
+    }
+      else
+    DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n");
+      }
+#endif /* DISABLE_OCSP */
+    }
+return 0;
+}
+
+static int
+creds_load_client_certs(exim_gnutls_state_st * state, const host_item * host,
+  const uschar * cert, const uschar * pkey, uschar ** errstr)
+{
+int rc = tls_add_certfile(state, host, cert, pkey, errstr);
+if (rc > 0) return rc;
+DEBUG(D_tls) debug_printf("TLS: cert/key registered\n");
+return 0;
+}
+
+static int
+creds_load_cabundle(exim_gnutls_state_st * state, const uschar * bundle,
+  const host_item * host, uschar ** errstr)
+{
+int cert_count;
+struct stat statbuf;
+
+#ifdef SUPPORT_SYSDEFAULT_CABUNDLE
+if (Ustrcmp(bundle, "system") == 0 || Ustrncmp(bundle, "system,", 7) == 0)
+  cert_count = gnutls_certificate_set_x509_system_trust(state->lib_state.x509_cred);
+else
+#endif
+  {
+  if (Ustat(bundle, &statbuf) < 0)
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC, "could not stat '%s' "
+    "(tls_verify_certificates): %s", bundle, strerror(errno));
+    return DEFER;
+    }
+
+#ifndef SUPPORT_CA_DIR
+  /* The test suite passes in /dev/null; we could check for that path explicitly,
+  but who knows if someone has some weird FIFO which always dumps some certs, or
+  other weirdness.  The thing we really want to check is that it's not a
+  directory, since while OpenSSL supports that, GnuTLS does not.
+  So s/!S_ISREG/S_ISDIR/ and change some messaging ... */
+  if (S_ISDIR(statbuf.st_mode))
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC,
+    "tls_verify_certificates \"%s\" is a directory", bundle);
+    return DEFER;
+    }
+#endif
+
+  DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n",
+      bundle, statbuf.st_size);
+
+  if (statbuf.st_size == 0)
+    {
+    DEBUG(D_tls)
+      debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n");
+    return OK;
+    }
+
+  cert_count =
+
+#ifdef SUPPORT_CA_DIR
+    (statbuf.st_mode & S_IFMT) == S_IFDIR
+    ?
+    gnutls_certificate_set_x509_trust_dir(state->lib_state.x509_cred,
+      CS bundle, GNUTLS_X509_FMT_PEM)
+    :
+#endif
+    gnutls_certificate_set_x509_trust_file(state->lib_state.x509_cred,
+      CS bundle, GNUTLS_X509_FMT_PEM);
+
+#ifdef SUPPORT_CA_DIR
+  /* Mimic the behaviour with OpenSSL of not advertising a usable-cert list
+  when using the directory-of-certs config model. */
+
+  if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
+    if (state->session)
+      gnutls_certificate_send_x509_rdn_sequence(state->session, 1);
+    else
+      state->lib_state.ca_rdn_emulate = TRUE;
+#endif
+  }
+
+if (cert_count < 0)
+  return tls_error_gnu(US"setting certificate trust", cert_count, host, errstr);
+DEBUG(D_tls)
+  debug_printf("Added %d certificate authorities\n", cert_count);
+
+return OK;
+}
+
+
+static int
+creds_load_crl(exim_gnutls_state_st * state, const uschar * crl, uschar ** errstr)
+{
+int cert_count;
+DEBUG(D_tls) debug_printf("loading CRL file = %s\n", crl);
+if ((cert_count = gnutls_certificate_set_x509_crl_file(state->lib_state.x509_cred,
+    CS crl, GNUTLS_X509_FMT_PEM)) < 0)
+  return tls_error_gnu(US"gnutls_certificate_set_x509_crl_file",
+        cert_count, state->host, errstr);
+
+DEBUG(D_tls) debug_printf("Processed %d CRLs\n", cert_count);
+return OK;
+}
+
+
+static int
+creds_load_pristring(exim_gnutls_state_st * state, const uschar * p,
+  const char ** errpos)
+{
+if (!p)
+  {
+  p = exim_default_gnutls_priority;
+  DEBUG(D_tls)
+    debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", p);
+  }
+return gnutls_priority_init( (gnutls_priority_t *) &state->lib_state.pri_cache,
+  CCS p, errpos);
+}
+
+static void
+tls_server_creds_init(void)
+{
+uschar * dummy_errstr;
+
+state_server.lib_state = null_tls_preload;
+if (gnutls_certificate_allocate_credentials(
+      (gnutls_certificate_credentials_t *) &state_server.lib_state.x509_cred))
+  {
+  state_server.lib_state.x509_cred = NULL;
+  return;
+  }
+creds_basic_init(state_server.lib_state.x509_cred, TRUE);
+
+#ifdef EXIM_HAVE_INOTIFY
+/* If tls_certificate has any $ indicating expansions, it is not good.
+If tls_privatekey is set but has $, not good.  Likewise for tls_ocsp_file.
+If all good (and tls_certificate set), load the cert(s).  Do not try
+to handle selfsign generation for now (tls_certificate null/empty;
+XXX will want to do that later though) due to the lifetime/expiry issue. */
+
+if (  opt_set_and_noexpand(tls_certificate)
+   && opt_unset_or_noexpand(tls_privatekey)
+   && opt_unset_or_noexpand(tls_ocsp_file))
+  {
+  /* Set watches on the filenames.  The implementation does de-duplication
+  so we can just blindly do them all.
+  */
+
+  if (  tls_set_watch(tls_certificate, TRUE)
+     && tls_set_watch(tls_privatekey, TRUE)
+     && tls_set_watch(tls_ocsp_file, TRUE)
+     )
+    {
+    DEBUG(D_tls) debug_printf("TLS: preloading server certs\n");
+    if (creds_load_server_certs(&state_server, tls_certificate,
+      tls_privatekey && *tls_privatekey ? tls_privatekey : tls_certificate,
+      tls_ocsp_file, &dummy_errstr) == 0)
+      state_server.lib_state.conn_certs = TRUE;
+    }
+  }
+else
+  DEBUG(D_tls) debug_printf("TLS: not preloading server certs\n");
+
+/* If tls_verify_certificates is non-empty and has no $, load CAs */
+
+if (opt_set_and_noexpand(tls_verify_certificates))
+  {
+  if (tls_set_watch(tls_verify_certificates, FALSE))
+    {
+    DEBUG(D_tls) debug_printf("TLS: preloading CA bundle for server\n");
+    if (creds_load_cabundle(&state_server, tls_verify_certificates,
+                NULL, &dummy_errstr) != OK)
+      return;
+    state_server.lib_state.cabundle = TRUE;
+
+    /* If CAs loaded and tls_crl is non-empty and has no $, load it */
+
+    if (opt_set_and_noexpand(tls_crl))
+      {
+      if (tls_set_watch(tls_crl, FALSE))
+    {
+    DEBUG(D_tls) debug_printf("TLS: preloading CRL for server\n");
+    if (creds_load_crl(&state_server, tls_crl, &dummy_errstr) != OK)
+      return;
+    state_server.lib_state.crl = TRUE;
+    }
+      }
+    else
+      DEBUG(D_tls) debug_printf("TLS: not preloading CRL for server\n");
+    }
+  }
+else
+  DEBUG(D_tls) debug_printf("TLS: not preloading CA bundle for server\n");
+#endif    /* EXIM_HAVE_INOTIFY */
+
+/* If tls_require_ciphers is non-empty and has no $, load the
+ciphers priority cache.  If unset, load with the default.
+(server-only as the client one depends on non/DANE) */
+
+if (!tls_require_ciphers || opt_set_and_noexpand(tls_require_ciphers))
+  {
+  const char * dummy_errpos;
+  DEBUG(D_tls) debug_printf("TLS: preloading cipher list for server: %s\n",
+          tls_require_ciphers);
+  if (  creds_load_pristring(&state_server, tls_require_ciphers, &dummy_errpos)
+     == OK)
+    state_server.lib_state.pri_string = TRUE;
+  }
+else
+  DEBUG(D_tls) debug_printf("TLS: not preloading cipher list for server\n");
+}
+
+
+/* Preload whatever creds are static, onto a transport.  The client can then
+just copy the pointer as it starts up. */
+
+static void
+tls_client_creds_init(transport_instance * t, BOOL watch)
+{
+smtp_transport_options_block * ob = t->options_block;
+exim_gnutls_state_st tpt_dummy_state;
+host_item * dummy_host = (host_item *)1;
+uschar * dummy_errstr;
+
+if (!exim_gnutls_base_init_done)
+  tls_g_init();
+
+ob->tls_preload = null_tls_preload;
+if (gnutls_certificate_allocate_credentials(
+  (struct gnutls_certificate_credentials_st **)&ob->tls_preload.x509_cred))
+  {
+  ob->tls_preload.x509_cred = NULL;
+  return;
+  }
+creds_basic_init(ob->tls_preload.x509_cred, FALSE);
+
+tpt_dummy_state.session = NULL;
+tpt_dummy_state.lib_state = ob->tls_preload;
+
+#ifdef EXIM_HAVE_INOTIFY
+if (  opt_set_and_noexpand(ob->tls_certificate)
+   && opt_unset_or_noexpand(ob->tls_privatekey))
+  {
+  if (  !watch
+     || (  tls_set_watch(ob->tls_certificate, FALSE)
+    && tls_set_watch(ob->tls_privatekey, FALSE)
+     )  )
+    {
+    const uschar * pkey = ob->tls_privatekey;
+
+    DEBUG(D_tls)
+      debug_printf("TLS: preloading client certs for transport '%s'\n", t->name);
+
+    /* The state->lib_state.x509_cred is used for the certs load, and is the sole
+    structure element used.  So we can set up a dummy.  The hoat arg only
+    selects a retcode in case of fail, so any value */
+
+    if (creds_load_client_certs(&tpt_dummy_state, dummy_host,
+      ob->tls_certificate, pkey ? pkey : ob->tls_certificate,
+      &dummy_errstr) == OK)
+      ob->tls_preload.conn_certs = TRUE;
+    }
+  }
+else
+  DEBUG(D_tls)
+    debug_printf("TLS: not preloading client certs, for transport '%s'\n", t->name);
+
+if (opt_set_and_noexpand(ob->tls_verify_certificates))
+  {
+  if (!watch || tls_set_watch(ob->tls_verify_certificates, FALSE))
+    {
+    DEBUG(D_tls)
+      debug_printf("TLS: preloading CA bundle for transport '%s'\n", t->name);
+    if (creds_load_cabundle(&tpt_dummy_state, ob->tls_verify_certificates,
+                dummy_host, &dummy_errstr) != OK)
+      return;
+    ob->tls_preload.cabundle = TRUE;
+
+    if (opt_set_and_noexpand(ob->tls_crl))
+      {
+      if (!watch || tls_set_watch(ob->tls_crl, FALSE))
+    {
+    DEBUG(D_tls) debug_printf("TLS: preloading CRL for transport '%s'\n", t->name);
+    if (creds_load_crl(&tpt_dummy_state, ob->tls_crl, &dummy_errstr) != OK)
+      return;
+    ob->tls_preload.crl = TRUE;
+    }
+      }
+    else
+      DEBUG(D_tls) debug_printf("TLS: not preloading CRL, for transport '%s'\n", t->name);
+    }
+  }
+else
+  DEBUG(D_tls)
+      debug_printf("TLS: not preloading CA bundle, for transport '%s'\n", t->name);
+
+/* We do not preload tls_require_ciphers to to the transport as it implicitly
+depends on DANE or plain usage. */
+
+#endif
 }


-/* Callback for handshake messages, on server */
-static int
-tls_server_hook_cb(gnutls_session_t sess, u_int htype, unsigned when,
-  unsigned incoming, const gnutls_datum_t * msg)
+
+#ifdef EXIM_HAVE_INOTIFY
+/* Invalidate the creds cached, by dropping the current ones.
+Call when we notice one of the source files has changed. */
+ 
+static void
+tls_server_creds_invalidate(void)
 {
-/* debug_printf("%s: htype %u\n", __FUNCTION__, htype); */
-switch (htype)
-  {
-# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
-  case GNUTLS_HANDSHAKE_CLIENT_HELLO:
-    return tls_server_clienthello_cb(sess, htype, when, incoming, msg);
-  case GNUTLS_HANDSHAKE_CERTIFICATE_PKT:
-    return tls_server_servercerts_cb(sess, htype, when, incoming, msg);
-# endif
-  case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS:
-    return tls_server_certstatus_cb(sess, htype, when, incoming, msg);
-# ifdef EXIM_HAVE_TLS_RESUME
-  case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET:
-    return tls_server_ticket_cb(sess, htype, when, incoming, msg);
-# endif
-  default:
-    return 0;
-  }
+if (state_server.lib_state.pri_cache)
+  gnutls_priority_deinit(state_server.lib_state.pri_cache);
+state_server.lib_state.pri_cache = NULL;
+
+if (state_server.lib_state.x509_cred)
+  gnutls_certificate_free_credentials(state_server.lib_state.x509_cred);
+state_server.lib_state = null_tls_preload;
 }
-#endif



-#if !defined(DISABLE_OCSP) && defined(SUPPORT_GNUTLS_EXT_RAW_PARSE)
 static void
-tls_server_testharness_ocsp_fiddle(void)
+tls_client_creds_invalidate(transport_instance * t)
 {
-extern char ** environ;
-if (environ) for (uschar ** p = USS environ; *p; p++)
-  if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
-    {
-    DEBUG(D_tls) debug_printf("Permitting known bad OCSP response\n");
-    exim_testharness_disable_ocsp_validity_check = TRUE;
-    }
+smtp_transport_options_block * ob = t->options_block;
+if (ob->tls_preload.x509_cred)
+  gnutls_certificate_free_credentials(ob->tls_preload.x509_cred);
+ob->tls_preload = null_tls_preload;
 }
 #endif


+
 /*************************************************
 *       Variables re-expanded post-SNI           *
 *************************************************/
@@ -1090,13 +1651,12 @@ Returns:          OK/DEFER/FAIL
 static int
 tls_expand_session_files(exim_gnutls_state_st * state, uschar ** errstr)
 {
-struct stat statbuf;
 int rc;
 const host_item *host = state->host;  /* macro should be reconsidered? */
-uschar *saved_tls_certificate = NULL;
-uschar *saved_tls_privatekey = NULL;
-uschar *saved_tls_verify_certificates = NULL;
-uschar *saved_tls_crl = NULL;
+const uschar *saved_tls_certificate = NULL;
+const uschar *saved_tls_privatekey = NULL;
+const uschar *saved_tls_verify_certificates = NULL;
+const uschar *saved_tls_crl = NULL;
 int cert_count;


 /* We check for tls_sni *before* expansion. */
@@ -1109,11 +1669,11 @@ if (!host)    /* server */
       || Ustrstr(state->tls_certificate, US"tls_out_sni")
        )  )
       {
-      DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n");
+      DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI\n");
       state->trigger_sni_changes = TRUE;
       }
     }
-  else
+  else    /* SNI callback case */
     {
     /* useful for debugging */
     saved_tls_certificate = state->exp_tls_certificate;
@@ -1122,180 +1682,91 @@ if (!host)    /* server */
     saved_tls_crl = state->exp_tls_crl;
     }


-if ((rc = gnutls_certificate_allocate_credentials(&state->x509_cred)))
-  return tls_error_gnu(US"gnutls_certificate_allocate_credentials",
-        rc, host, errstr);
-
-#ifdef SUPPORT_SRV_OCSP_STACK
-gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2);
-
-# if !defined(DISABLE_OCSP) && defined(SUPPORT_GNUTLS_EXT_RAW_PARSE)
-if (!host && tls_ocsp_file)
+if (!state->lib_state.x509_cred)
   {
-  if (f.running_in_test_harness)
-    tls_server_testharness_ocsp_fiddle();
-
-  if (exim_testharness_disable_ocsp_validity_check)
-    gnutls_certificate_set_flags(state->x509_cred,
-      GNUTLS_CERTIFICATE_API_V2 | GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK);
+  if ((rc = gnutls_certificate_allocate_credentials(
+    (gnutls_certificate_credentials_t *) &state->lib_state.x509_cred)))
+    return tls_error_gnu(US"gnutls_certificate_allocate_credentials",
+        rc, host, errstr);
+  creds_basic_init(state->lib_state.x509_cred, !host);
   }
-# endif
-#endif


-/* remember: expand_check_tlsvar() is expand_check() but fiddling with
+
+/* remember: Expand_check_tlsvar() is expand_check() but fiddling with
state members, assuming consistent naming; and expand_check() returns
false if expansion failed, unless expansion was forced to fail. */

/* check if we at least have a certificate, before doing expensive
D-H generation. */

-if (!expand_check_tlsvar(tls_certificate, errstr))
-  return DEFER;
-
-/* certificate is mandatory in server, optional in client */
-
-if (  !state->exp_tls_certificate
-   || !*state->exp_tls_certificate
-   )
-  if (!host)
-    return tls_install_selfsign(state, errstr);
-  else
-    DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n");
-
-if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr))
-  return DEFER;
-
-/* tls_privatekey is optional, defaulting to same file as certificate */
-
-if (!state->tls_privatekey || !*state->tls_privatekey)
+if (!state->lib_state.conn_certs)
   {
-  state->tls_privatekey = state->tls_certificate;
-  state->exp_tls_privatekey = state->exp_tls_certificate;
-  }
-
+  if (!Expand_check_tlsvar(tls_certificate, errstr))
+    return DEFER;


-if (state->exp_tls_certificate && *state->exp_tls_certificate)
-  {
-  DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n",
-      state->exp_tls_certificate, state->exp_tls_privatekey);
+  /* certificate is mandatory in server, optional in client */


-  if (state->received_sni)
-    if (  Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0
-       && Ustrcmp(state->exp_tls_privatekey,  saved_tls_privatekey)  == 0
-       )
-      {
-      DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n");
-      }
+  if (  !state->exp_tls_certificate
+     || !*state->exp_tls_certificate
+     )
+    if (!host)
+      return tls_install_selfsign(state, errstr);
     else
-      {
-      DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n");
-      }
-
-  if (!host)    /* server */
-    {
-    const uschar * clist = state->exp_tls_certificate;
-    const uschar * klist = state->exp_tls_privatekey;
-    const uschar * olist;
-    int csep = 0, ksep = 0, osep = 0, cnt = 0;
-    uschar * cfile, * kfile, * ofile;
-#ifndef DISABLE_OCSP
-# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
-    gnutls_x509_crt_fmt_t ocsp_fmt = GNUTLS_X509_FMT_DER;
-# endif
-
-    if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr))
-      return DEFER;
-    olist = ofile;
-#endif
-
-    while (cfile = string_nextinlist(&clist, &csep, NULL, 0))
+      DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n");


-      if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0)))
-    return tls_error(US"cert/key setup: out of keys", NULL, host, errstr);
-      else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr)))
-    return rc;
-      else
-    {
-    int gnutls_cert_index = -rc;
-    DEBUG(D_tls) debug_printf("TLS: cert/key %d %s registered\n",
-                  gnutls_cert_index, cfile);
+  if (state->tls_privatekey && !Expand_check_tlsvar(tls_privatekey, errstr))
+    return DEFER;


-#ifndef DISABLE_OCSP
-    if (tls_ocsp_file)
-      {
-      /* Set the OCSP stapling server info */
-      if (gnutls_buggy_ocsp)
-        {
-        DEBUG(D_tls)
-          debug_printf("GnuTLS library is buggy for OCSP; avoiding\n");
-        }
-      else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0)))
-        {
-        DEBUG(D_tls) debug_printf("OCSP response file %d  = %s\n",
-                      gnutls_cert_index, ofile);
-# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
-        if (Ustrncmp(ofile, US"PEM ", 4) == 0)
-          {
-          ocsp_fmt = GNUTLS_X509_FMT_PEM;
-          ofile += 4;
-          }
-        else if (Ustrncmp(ofile, US"DER ", 4) == 0)
-          {
-          ocsp_fmt = GNUTLS_X509_FMT_DER;
-          ofile += 4;
-          }
-
-        if  ((rc = gnutls_certificate_set_ocsp_status_request_file2(
-              state->x509_cred, CCS ofile, gnutls_cert_index,
-              ocsp_fmt)) < 0)
-          return tls_error_gnu(
-              US"gnutls_certificate_set_ocsp_status_request_file2",
-              rc, host, errstr);
-        DEBUG(D_tls)
-          debug_printf(" %d response%s loaded\n", rc, rc>1 ? "s":"");
+  /* tls_privatekey is optional, defaulting to same file as certificate */


-        /* Arrange callbacks for OCSP request observability */
+  if (!state->tls_privatekey || !*state->tls_privatekey)
+    {
+    state->tls_privatekey = state->tls_certificate;
+    state->exp_tls_privatekey = state->exp_tls_certificate;
+    }


-        gnutls_handshake_set_hook_function(state->session,
-          GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb);
+  if (state->exp_tls_certificate && *state->exp_tls_certificate)
+    {
+    BOOL load = TRUE;
+    DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n",
+    state->exp_tls_certificate, state->exp_tls_privatekey);


-# else
-#  if defined(SUPPORT_SRV_OCSP_STACK)
-        if ((rc = gnutls_certificate_set_ocsp_status_request_function2(
-             state->x509_cred, gnutls_cert_index,
-             server_ocsp_stapling_cb, ofile)))
-        return tls_error_gnu(
-              US"gnutls_certificate_set_ocsp_status_request_function2",
-              rc, host, errstr);
-        else
-#  endif
-          {
-          if (cnt++ > 0)
-        {
-        DEBUG(D_tls)
-          debug_printf("oops; multiple OCSP files not supported\n");
-        break;
-        }
-          gnutls_certificate_set_ocsp_status_request_function(
-        state->x509_cred, server_ocsp_stapling_cb, ofile);
-          }
-# endif    /* SUPPORT_GNUTLS_EXT_RAW_PARSE */
-        }
-      else
-        DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n");
-      }
-#endif /* DISABLE_OCSP */
+    if (state->received_sni)
+      if (  Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0
+     && Ustrcmp(state->exp_tls_privatekey,  saved_tls_privatekey)  == 0
+     )
+    {
+    DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n");
+    load = FALSE;    /* avoid re-loading the same certs */
     }
+      else        /* unload the pre-SNI certs before loading new ones */
+    {
+    DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair\n");
+    gnutls_certificate_free_keys(state->lib_state.x509_cred);
+    }
+
+    if (  load
+       && (rc = host
+      ? creds_load_client_certs(state, host, state->exp_tls_certificate,
+                  state->exp_tls_privatekey, errstr)
+      : creds_load_server_certs(state, state->exp_tls_certificate,
+                  state->exp_tls_privatekey, tls_ocsp_file, errstr)
+       )  ) return rc;
     }
-  else    /* client */
-    {
-    if (0 < (rc = tls_add_certfile(state, host,
-        state->exp_tls_certificate, state->exp_tls_privatekey, errstr)))
-      return rc;
-    DEBUG(D_tls) debug_printf("TLS: cert/key registered\n");
-    }
+  }
+else
+  {
+  DEBUG(D_tls)
+    debug_printf("%s certs were preloaded\n", host ? "client" : "server");
+
+  if (!state->tls_privatekey) state->tls_privatekey = state->tls_certificate;
+  state->exp_tls_certificate = US state->tls_certificate;
+  state->exp_tls_privatekey = US state->tls_privatekey;


-  } /* tls_certificate */
+  if (state->lib_state.ocsp_hook)
+     gnutls_handshake_set_hook_function(state->session,
+       GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb);
+  }



/* Set the trusted CAs file if one is provided, and then add the CRL if one is
@@ -1304,112 +1775,64 @@ error message is provided. However, if we just refrain from setting anything up
in that case, certificate verification fails, which seems to be the correct
behaviour. */

-if (state->tls_verify_certificates && *state->tls_verify_certificates)
+if (!state->lib_state.cabundle)
   {
-  if (!expand_check_tlsvar(tls_verify_certificates, errstr))
-    return DEFER;
+  if (state->tls_verify_certificates && *state->tls_verify_certificates)
+    {
+    if (!Expand_check_tlsvar(tls_verify_certificates, errstr))
+      return DEFER;
 #ifndef SUPPORT_SYSDEFAULT_CABUNDLE
-  if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0)
-    state->exp_tls_verify_certificates = NULL;
+    if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0)
+      state->exp_tls_verify_certificates = NULL;
 #endif
-  if (state->tls_crl && *state->tls_crl)
-    if (!expand_check_tlsvar(tls_crl, errstr))
-      return DEFER;
+    if (state->tls_crl && *state->tls_crl)
+      if (!Expand_check_tlsvar(tls_crl, errstr))
+    return DEFER;


-  if (!(state->exp_tls_verify_certificates &&
-        *state->exp_tls_verify_certificates))
+    if (!(state->exp_tls_verify_certificates &&
+      *state->exp_tls_verify_certificates))
+      {
+      DEBUG(D_tls)
+    debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n");
+      /* With no tls_verify_certificates, we ignore tls_crl too */
+      return OK;
+      }
+    }
+  else
     {
     DEBUG(D_tls)
-      debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n");
-    /* With no tls_verify_certificates, we ignore tls_crl too */
+      debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n");
     return OK;
     }
+  rc = creds_load_cabundle(state, state->exp_tls_verify_certificates, host, errstr);
+  if (rc != OK) return rc;
   }
 else
   {
   DEBUG(D_tls)
-    debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n");
-  return OK;
-  }
-
-#ifdef SUPPORT_SYSDEFAULT_CABUNDLE
-if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0)
-  cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred);
-else
-#endif
-  {
-  if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0)
-    {
-    log_write(0, LOG_MAIN|LOG_PANIC, "could not stat '%s' "
-    "(tls_verify_certificates): %s", state->exp_tls_verify_certificates,
-    strerror(errno));
-    return DEFER;
-    }
-
-#ifndef SUPPORT_CA_DIR
-  /* The test suite passes in /dev/null; we could check for that path explicitly,
-  but who knows if someone has some weird FIFO which always dumps some certs, or
-  other weirdness.  The thing we really want to check is that it's not a
-  directory, since while OpenSSL supports that, GnuTLS does not.
-  So s/!S_ISREG/S_ISDIR/ and change some messaging ... */
-  if (S_ISDIR(statbuf.st_mode))
-    {
-    DEBUG(D_tls)
-      debug_printf("verify certificates path is a dir: \"%s\"\n",
-      state->exp_tls_verify_certificates);
-    log_write(0, LOG_MAIN|LOG_PANIC,
-    "tls_verify_certificates \"%s\" is a directory",
-    state->exp_tls_verify_certificates);
-    return DEFER;
-    }
-#endif
-
-  DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n",
-      state->exp_tls_verify_certificates, statbuf.st_size);
-
-  if (statbuf.st_size == 0)
-    {
-    DEBUG(D_tls)
-      debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n");
-    return OK;
-    }
-
-  cert_count =
-
-#ifdef SUPPORT_CA_DIR
-    (statbuf.st_mode & S_IFMT) == S_IFDIR
-    ?
-    gnutls_certificate_set_x509_trust_dir(state->x509_cred,
-      CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM)
-    :
-#endif
-    gnutls_certificate_set_x509_trust_file(state->x509_cred,
-      CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM);
+    debug_printf("%s CA bundle was preloaded\n", host ? "client" : "server");
+  state->exp_tls_verify_certificates = US state->tls_verify_certificates;


 #ifdef SUPPORT_CA_DIR
-  /* Mimic the behaviour with OpenSSL of not advertising a usable-cert list
-  when using the directory-of-certs config model. */
-
-  if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
-    gnutls_certificate_send_x509_rdn_sequence(state->session, 1);
+/* Mimic the behaviour with OpenSSL of not advertising a usable-cert list
+when using the directory-of-certs config model. */
+    if (state->lib_state.ca_rdn_emulate)
+      gnutls_certificate_send_x509_rdn_sequence(state->session, 1);
 #endif
   }


-if (cert_count < 0)
- return tls_error_gnu(US"setting certificate trust", cert_count, host, errstr);
-DEBUG(D_tls)
- debug_printf("Added %d certificate authorities.\n", cert_count);

-if (state->tls_crl && *state->tls_crl &&
-    state->exp_tls_crl && *state->exp_tls_crl)
+if (!state->lib_state.crl)
   {
-  DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl);
-  if ((cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred,
-      CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM)) < 0)
-    return tls_error_gnu(US"gnutls_certificate_set_x509_crl_file",
-          cert_count, host, errstr);
-
-  DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count);
+  if (  state->tls_crl && *state->tls_crl
+     && state->exp_tls_crl && *state->exp_tls_crl)
+    return creds_load_crl(state, state->exp_tls_crl, errstr);
+  }
+else
+  {
+  DEBUG(D_tls)
+      debug_printf("%s CRL was preloaded\n", host ? "client" : "server");
+  state->exp_tls_crl = US state->tls_crl;
   }


return OK;
@@ -1448,18 +1871,19 @@ client-side params. */

 if (!state->host)
   {
+/*XXX DDD done-bit */
   if (!dh_server_params)
     if ((rc = init_server_dh(errstr)) != OK) return rc;


/* Unnecessary & discouraged with 3.6.0 or later */
- gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params);
+ gnutls_certificate_set_dh_params(state->.lib_statex509_cred, dh_server_params);
}
#endif

/* Link the credentials to the session. */

 if ((rc = gnutls_credentials_set(state->session,
-        GNUTLS_CRD_CERTIFICATE, state->x509_cred)))
+        GNUTLS_CRD_CERTIFICATE, state->lib_state.x509_cred)))
   return tls_error_gnu(US"gnutls_credentials_set", rc, host, errstr);


return OK;
@@ -1470,47 +1894,12 @@ return OK;
*************************************************/


-#ifndef DISABLE_OCSP
-
-static BOOL
-tls_is_buggy_ocsp(void)
-{
-const uschar * s;
-uschar maj, mid, mic;
-
-s = CUS gnutls_check_version(NULL);
-maj = atoi(CCS s);
-if (maj == 3)
-  {
-  while (*s && *s != '.') s++;
-  mid = atoi(CCS ++s);
-  if (mid <= 2)
-    return TRUE;
-  else if (mid >= 5)
-    return FALSE;
-  else
-    {
-    while (*s && *s != '.') s++;
-    mic = atoi(CCS ++s);
-    return mic <= (mid == 3 ? 16 : 3);
-    }
-  }
-return FALSE;
-}
-
-#endif
-
-
 /* Called from both server and client code. In the case of a server, errors
 before actual TLS negotiation return DEFER.


 Arguments:
   host            connected host, if client; NULL if server
-  certificate     certificate file
-  privatekey      private key file
-  sni             TLS SNI to send, sometimes when client; else NULL
-  cas             CA certs file
-  crl             CRL file
+  ob          tranport options block, if client; NULL if server
   require_ciphers tls_require_ciphers setting
   caller_state    returned state-info structure
   errstr      error string pointer
@@ -1521,12 +1910,8 @@ Returns:          OK/DEFER/FAIL
 static int
 tls_init(
     const host_item *host,
-    const uschar *certificate,
-    const uschar *privatekey,
-    const uschar *sni,
-    const uschar *cas,
-    const uschar *crl,
-    const uschar *require_ciphers,
+    smtp_transport_options_block * ob,
+    const uschar * require_ciphers,
     exim_gnutls_state_st **caller_state,
     tls_support * tlsp,
     uschar ** errstr)
@@ -1534,85 +1919,60 @@ tls_init(
 exim_gnutls_state_st * state;
 int rc;
 size_t sz;
-const char * errpos;
-const uschar * p;


 if (!exim_gnutls_base_init_done)
-  {
-  DEBUG(D_tls) debug_printf("GnuTLS global init required.\n");
-
-#if defined(HAVE_GNUTLS_PKCS11) && !defined(GNUTLS_AUTO_PKCS11_MANUAL)
-  /* By default, gnutls_global_init will init PKCS11 support in auto mode,
-  which loads modules from a config file, which sounds good and may be wanted
-  by some sysadmin, but also means in common configurations that GNOME keyring
-  environment variables are used and so breaks for users calling mailq.
-  To prevent this, we init PKCS11 first, which is the documented approach. */
-  if (!gnutls_allow_auto_pkcs11)
-    if ((rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL)))
-      return tls_error_gnu(US"gnutls_pkcs11_init", rc, host, errstr);
-#endif
-
-#ifndef GNUTLS_AUTO_GLOBAL_INIT
-  if ((rc = gnutls_global_init()))
-    return tls_error_gnu(US"gnutls_global_init", rc, host, errstr);
-#endif
-
-#if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0
-  DEBUG(D_tls)
-    {
-    gnutls_global_set_log_function(exim_gnutls_logger_cb);
-    /* arbitrarily chosen level; bump up to 9 for more */
-    gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL);
-    }
-#endif
-
-#ifndef DISABLE_OCSP
-  if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp()))
-    log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version");
-#endif
-
-  exim_gnutls_base_init_done = TRUE;
-  }
+  tls_g_init();


if (host)
{
/* For client-side sessions we allocate a context. This lets us run
several in parallel. */
+
int old_pool = store_pool;
store_pool = POOL_PERM;
state = store_get(sizeof(exim_gnutls_state_st), FALSE);
store_pool = old_pool;

   memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init));
+  state->lib_state = ob->tls_preload;
   state->tlsp = tlsp;
   DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n");
   rc = gnutls_init(&state->session, GNUTLS_CLIENT);
+
+  state->tls_certificate =    ob->tls_certificate;
+  state->tls_privatekey =    ob->tls_privatekey;
+  state->tls_sni =        ob->tls_sni;
+  state->tls_verify_certificates = ob->tls_verify_certificates;
+  state->tls_crl =        ob->tls_crl;
   }
 else
   {
+  /* Server operations always use the one state_server context.  It is not
+  shared because we have forked a fresh process for every receive.  However it
+  can get re-used for successive TLS sessions on a single TCP connection. */
+
   state = &state_server;
-  memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init));
   state->tlsp = tlsp;
   DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n");
   rc = gnutls_init(&state->session, GNUTLS_SERVER);
+
+  state->tls_certificate =    tls_certificate;
+  state->tls_privatekey =    tls_privatekey;
+  state->tls_sni =        NULL;
+  state->tls_verify_certificates = tls_verify_certificates;
+  state->tls_crl =        tls_crl;
   }
 if (rc)
   return tls_error_gnu(US"gnutls_init", rc, host, errstr);


+state->tls_require_ciphers =    require_ciphers;
 state->host = host;


-state->tls_certificate = certificate;
-state->tls_privatekey = privatekey;
-state->tls_require_ciphers = require_ciphers;
-state->tls_sni = sni;
-state->tls_verify_certificates = cas;
-state->tls_crl = crl;
-
/* This handles the variables that might get re-expanded after TLS SNI;
that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */

DEBUG(D_tls)
- debug_printf("Expanding various TLS configuration options for session credentials.\n");
+ debug_printf("Expanding various TLS configuration options for session credentials\n");
if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc;

 /* These are all other parts of the x509_cred handling, since SNI in GnuTLS
@@ -1623,7 +1983,7 @@ if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc;
 /* set SNI in client, only */
 if (host)
   {
-  if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr))
+  if (!expand_check(state->tls_sni, US"tls_out_sni", &state->tlsp->sni, errstr))
     return DEFER;
   if (state->tlsp->sni && *state->tlsp->sni)
     {
@@ -1639,37 +1999,42 @@ else if (state->tls_sni)
   DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \
       "have an SNI set for a server [%s]\n", state->tls_sni);


-/* This is the priority string support,
-http://www.gnutls.org/manual/html_node/Priority-Strings.html
-and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols.
-This was backwards incompatible, but means Exim no longer needs to track
-all algorithms and provide string forms for them. */
-
-p = NULL;
-if (state->tls_require_ciphers && *state->tls_require_ciphers)
+if (!state->lib_state.pri_string)
   {
-  if (!expand_check_tlsvar(tls_require_ciphers, errstr))
-    return DEFER;
-  if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers)
+  const uschar * p = NULL;
+  const char * errpos;
+
+  /* This is the priority string support,
+  http://www.gnutls.org/manual/html_node/Priority-Strings.html
+  and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols.
+  This was backwards incompatible, but means Exim no longer needs to track
+  all algorithms and provide string forms for them. */
+
+  if (state->tls_require_ciphers && *state->tls_require_ciphers)
     {
-    p = state->exp_tls_require_ciphers;
-    DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", p);
+    if (!Expand_check_tlsvar(tls_require_ciphers, errstr))
+      return DEFER;
+    if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers)
+      {
+      p = state->exp_tls_require_ciphers;
+      DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", p);
+      }
     }
+
+  if ((rc = creds_load_pristring(state, p, &errpos)))
+    return tls_error_gnu(string_sprintf(
+            "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"",
+            p, errpos - CS p, errpos),
+            rc, host, errstr);
   }
-if (!p)
+else
   {
-  p = exim_default_gnutls_priority;
-  DEBUG(D_tls)
-    debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", p);
+  DEBUG(D_tls) debug_printf("cipher list preloaded\n");
+  state->exp_tls_require_ciphers = US state->tls_require_ciphers;
   }


-if ((rc = gnutls_priority_init(&state->priority_cache, CCS p, &errpos)))
-  return tls_error_gnu(string_sprintf(
-              "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"",
-              p, errpos - CS p, errpos),
-          rc, host, errstr);


-if ((rc = gnutls_priority_set(state->session, state->priority_cache)))
+if ((rc = gnutls_priority_set(state->session, state->lib_state.pri_cache)))
return tls_error_gnu(US"gnutls_priority_set", rc, host, errstr);

 /* This also sets the server ticket expiration time to the same, and
@@ -2196,7 +2561,7 @@ if (rc != GNUTLS_E_SUCCESS)
   {
   DEBUG(D_tls)
     if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
-      debug_printf("TLS: no SNI presented in handshake.\n");
+      debug_printf("TLS: no SNI presented in handshake\n");
     else
       debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n",
         gnutls_strerror(rc), rc);
@@ -2407,7 +2772,6 @@ the STARTTLS command. It must respond to that command, and then negotiate
 a TLS session.


 Arguments:
-  require_ciphers  list of allowed ciphers or NULL
   errstr       pointer to error string


 Returns:           OK on success
@@ -2417,7 +2781,7 @@ Returns:           OK on success
 */


int
-tls_server_start(const uschar * require_ciphers, uschar ** errstr)
+tls_server_start(uschar ** errstr)
{
int rc;
exim_gnutls_state_st * state = NULL;
@@ -2441,9 +2805,8 @@ DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n");
gettimeofday(&t0, NULL);
#endif

-  if ((rc = tls_init(NULL, tls_certificate, tls_privatekey,
-      NULL, tls_verify_certificates, tls_crl,
-      require_ciphers, &state, &tls_in, errstr)) != OK) return rc;
+  if ((rc = tls_init(NULL, NULL,
+      tls_require_ciphers, &state, &tls_in, errstr)) != OK) return rc;


 #ifdef MEASURE_TIMING
   report_time_since(&t0, US"server tls_init (delta)");
@@ -2460,21 +2823,21 @@ optional, set up appropriately. */
 if (verify_check_host(&tls_verify_hosts) == OK)
   {
   DEBUG(D_tls)
-    debug_printf("TLS: a client certificate will be required.\n");
+    debug_printf("TLS: a client certificate will be required\n");
   state->verify_requirement = VERIFY_REQUIRED;
   gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE);
   }
 else if (verify_check_host(&tls_try_verify_hosts) == OK)
   {
   DEBUG(D_tls)
-    debug_printf("TLS: a client certificate will be requested but not required.\n");
+    debug_printf("TLS: a client certificate will be requested but not required\n");
   state->verify_requirement = VERIFY_OPTIONAL;
   gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST);
   }
 else
   {
   DEBUG(D_tls)
-    debug_printf("TLS: a client certificate will not be requested.\n");
+    debug_printf("TLS: a client certificate will not be requested\n");
   state->verify_requirement = VERIFY_NONE;
   gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE);
   }
@@ -2484,7 +2847,7 @@ if (event_action)
   {
   state->event_action = event_action;
   gnutls_session_set_ptr(state->session, state);
-  gnutls_certificate_set_verify_function(state->x509_cred, verify_cb);
+  gnutls_certificate_set_verify_function(state->lib_state.x509_cred, verify_cb);
   }
 #endif


@@ -2541,7 +2904,8 @@ if (rc != GNUTLS_E_SUCCESS)
     tls_error_gnu(US"gnutls_handshake", rc, NULL, errstr);
     (void) gnutls_alert_send_appropriate(state->session, rc);
     gnutls_deinit(state->session);
-    gnutls_certificate_free_credentials(state->x509_cred);
+    gnutls_certificate_free_credentials(state->lib_state.x509_cred);
+    state->lib_state = null_tls_preload;
     millisleep(500);
     shutdown(state->fd_out, SHUT_WR);
     for (int i = 1024; fgetc(smtp_in) != EOF && i > 0; ) i--;    /* drain skt */
@@ -2614,7 +2978,7 @@ if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK)
     host->certname;
 #endif
   DEBUG(D_tls)
-    debug_printf("TLS: server cert verification includes hostname: \"%s\".\n",
+    debug_printf("TLS: server cert verification includes hostname: \"%s\"\n",
             state->exp_tls_verify_cert_hostnames);
   }
 }
@@ -2875,7 +3239,7 @@ be requested and supplied, dane verify must pass, and cert verify irrelevant


 if (conn_args->dane && ob->dane_require_tls_ciphers)
   {
-  /* not using expand_check_tlsvar because not yet in state */
+  /* not using Expand_check_tlsvar because not yet in state */
   if (!expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers",
       &cipher_list, errstr))
     return FALSE;
@@ -2893,12 +3257,9 @@ if (!cipher_list)
   gettimeofday(&t0, NULL);
 #endif


-  if (tls_init(host, ob->tls_certificate, ob->tls_privatekey,
-      ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl,
-      cipher_list, &state, tlsp, errstr) != OK)
+  if (tls_init(host, ob, cipher_list, &state, tlsp, errstr) != OK)
     return FALSE;


-
 #ifdef MEASURE_TIMING
   report_time_since(&t0, US"client tls_init (delta)");
 #endif
@@ -2929,7 +3290,7 @@ the specified host patterns if one of them is defined */
 if (conn_args->dane && dane_tlsa_load(state, &conn_args->tlsa_dnsa))
   {
   DEBUG(D_tls)
-    debug_printf("TLS: server certificate DANE required.\n");
+    debug_printf("TLS: server certificate DANE required\n");
   state->verify_requirement = VERIFY_DANE;
   gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE);
   }
@@ -2944,7 +3305,7 @@ else
   {
   tls_client_setup_hostname_checks(host, state, ob);
   DEBUG(D_tls)
-    debug_printf("TLS: server certificate verification required.\n");
+    debug_printf("TLS: server certificate verification required\n");
   state->verify_requirement = VERIFY_REQUIRED;
   gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE);
   }
@@ -2952,14 +3313,14 @@ else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK)
   {
   tls_client_setup_hostname_checks(host, state, ob);
   DEBUG(D_tls)
-    debug_printf("TLS: server certificate verification optional.\n");
+    debug_printf("TLS: server certificate verification optional\n");
   state->verify_requirement = VERIFY_OPTIONAL;
   gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST);
   }
 else
   {
   DEBUG(D_tls)
-    debug_printf("TLS: server certificate verification not required.\n");
+    debug_printf("TLS: server certificate verification not required\n");
   state->verify_requirement = VERIFY_NONE;
   gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE);
   }
@@ -2988,7 +3349,7 @@ if (tb && tb->event_action)
   {
   state->event_action = tb->event_action;
   gnutls_session_set_ptr(state->session, state);
-  gnutls_certificate_set_verify_function(state->x509_cred, verify_cb);
+  gnutls_certificate_set_verify_function(state->lib_state.x509_cred, verify_cb);
   }
 #endif


@@ -3140,7 +3501,8 @@ if (!ct_ctx)    /* server */
   }


gnutls_deinit(state->session);
-gnutls_certificate_free_credentials(state->x509_cred);
+gnutls_certificate_free_credentials(state->lib_state.x509_cred);
+state->lib_state = null_tls_preload;

tlsp->active.sock = -1;
tlsp->active.tls_ctx = NULL;
@@ -3149,7 +3511,6 @@ tlsp->channelbinding = NULL;


if (state->xfer_buffer) store_free(state->xfer_buffer);
-memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init));
}


@@ -3507,7 +3868,7 @@ if (i < needed_len)
i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len);
if (i < 0)
{
- DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n");
+ DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback\n");
return vaguely_random_number_fallback(max);
}
r = 0;
diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c
index 6ce20f1..80485a4 100644
--- a/src/src/tls-openssl.c
+++ b/src/src/tls-openssl.c
@@ -274,6 +274,7 @@ static exim_openssl_option exim_openssl_options[] = {

#ifndef MACRO_PREDEF
static int exim_openssl_options_size = nelem(exim_openssl_options);
+static long init_options = 0;
#endif

 #ifdef MACRO_PREDEF
@@ -350,8 +351,9 @@ typedef struct {
   gstring *    corked;
 } exim_openssl_client_tls_ctx;


-static SSL_CTX *server_ctx = NULL;
-static SSL     *server_ssl = NULL;
+
+/* static SSL_CTX *server_ctx = NULL; */
+/* static SSL     *server_ssl = NULL; */


 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
 static SSL_CTX *server_sni = NULL;
@@ -371,7 +373,11 @@ typedef struct ocsp_resp {
   OCSP_RESPONSE *    resp;
 } ocsp_resplist;


-typedef struct tls_ext_ctx_cb {
+typedef struct exim_openssl_state {
+  exim_tlslib_state    lib_state;
+#define lib_ctx            libdata0
+#define lib_ssl            libdata1
+
   tls_support *    tlsp;
   uschar *    certificate;
   uschar *    privatekey;
@@ -399,17 +405,17 @@ typedef struct tls_ext_ctx_cb {
 #ifndef DISABLE_EVENT
   uschar *    event_action;
 #endif
-} tls_ext_ctx_cb;
+} exim_openssl_state_st;


 /* should figure out a cleanup of API to handle state preserved per
 implementation, for various reasons, which can be void * in the APIs.
 For now, we hack around it. */
-tls_ext_ctx_cb *client_static_cbinfo = NULL;    /*XXX should not use static; multiple concurrent clients! */
-tls_ext_ctx_cb *server_static_cbinfo = NULL;
+exim_openssl_state_st *client_static_state = NULL;    /*XXX should not use static; multiple concurrent clients! */
+exim_openssl_state_st state_server = {.is_server = TRUE};


 static int
-setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
-    int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr );
+setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host,
+    uschar ** errstr );


/* Callbacks */
#ifdef EXIM_HAVE_OPENSSL_TLSEXT
@@ -427,13 +433,20 @@ static void tk_init(void);
static int tls_exdata_idx = -1;
#endif

-void
-tls_daemon_init(void)
+static void
+tls_per_lib_daemon_tick(void)
{
#ifndef DISABLE_TLS_RESUME
tk_init();
#endif
-return;
+}
+
+/* Called once at daemon startup */
+
+static void
+tls_per_lib_daemon_init(void)
+{
+tls_daemon_creds_reload();
}


@@ -475,8 +488,270 @@ return host ? FAIL : DEFER;



+/**************************************************
+* General library initalisation                   *
+**************************************************/
+
+static BOOL
+lib_rand_init(void * addr)
+{
+randstuff r;
+if (!RAND_status()) return TRUE;
+
+gettimeofday(&r.tv, NULL);
+r.p = getpid();
+RAND_seed(US (&r), sizeof(r));
+RAND_seed(US big_buffer, big_buffer_size);
+if (addr) RAND_seed(US addr, sizeof(addr));
+
+return RAND_status();
+}
+
+
+static void
+tls_openssl_init(void)
+{
+static BOOL once = FALSE;
+if (once) return;
+once = TRUE;
+
+#ifdef EXIM_NEED_OPENSSL_INIT
+SSL_load_error_strings();          /* basic set up */
+OpenSSL_add_ssl_algorithms();
+#endif
+
+#if defined(EXIM_HAVE_SHA256) && !defined(OPENSSL_AUTO_SHA256)
+/* SHA256 is becoming ever more popular. This makes sure it gets added to the
+list of available digests. */
+EVP_add_digest(EVP_sha256());
+#endif
+
+(void) lib_rand_init(NULL);
+(void) tls_openssl_options_parse(openssl_options, &init_options);
+}
+
+
+
+/*************************************************
+*                Initialize for DH               *
+*************************************************/
+
+/* If dhparam is set, expand it, and load up the parameters for DH encryption.
+
+Arguments:
+  sctx      The current SSL CTX (inbound or outbound)
+  dhparam   DH parameter file or fixed parameter identity string
+  host      connected host, if client; NULL if server
+  errstr    error string pointer
+
+Returns:    TRUE if OK (nothing to set up, or setup worked)
+*/
+
+static BOOL
+init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr)
+{
+BIO *bio;
+DH *dh;
+uschar *dhexpanded;
+const char *pem;
+int dh_bitsize;
+
+if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr))
+  return FALSE;
+
+if (!dhexpanded || !*dhexpanded)
+  bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1);
+else if (dhexpanded[0] == '/')
+  {
+  if (!(bio = BIO_new_file(CS dhexpanded, "r")))
+    {
+    tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
+          host, US strerror(errno), errstr);
+    return FALSE;
+    }
+  }
+else
+  {
+  if (Ustrcmp(dhexpanded, "none") == 0)
+    {
+    DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
+    return TRUE;
+    }
+
+  if (!(pem = std_dh_prime_named(dhexpanded)))
+    {
+    tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded),
+        host, US strerror(errno), errstr);
+    return FALSE;
+    }
+  bio = BIO_new_mem_buf(CS pem, -1);
+  }
+
+if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)))
+  {
+  BIO_free(bio);
+  tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded),
+      host, NULL, errstr);
+  return FALSE;
+  }
+
+/* note: our default limit of 2236 is not a multiple of 8; the limit comes from
+ * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with
+ * 2236.  But older OpenSSL can only report in bytes (octets), not bits.
+ * If someone wants to dance at the edge, then they can raise the limit or use
+ * current libraries. */
+#ifdef EXIM_HAVE_OPENSSL_DH_BITS
+/* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022
+ * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */
+dh_bitsize = DH_bits(dh);
+#else
+dh_bitsize = 8 * DH_size(dh);
+#endif
+
+/* Even if it is larger, we silently return success rather than cause things
+ * to fail out, so that a too-large DH will not knock out all TLS; it's a
+ * debatable choice. */
+if (dh_bitsize > tls_dh_max_bits)
+  {
+  DEBUG(D_tls)
+    debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n",
+        dh_bitsize, tls_dh_max_bits);
+  }
+else
+  {
+  SSL_CTX_set_tmp_dh(sctx, dh);
+  DEBUG(D_tls)
+    debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n",
+      dhexpanded ? dhexpanded : US"default", dh_bitsize);
+  }
+
+DH_free(dh);
+BIO_free(bio);
+
+return TRUE;
+}
+
+
+
+
+/*************************************************
+*               Initialize for ECDH              *
+*************************************************/
+
+/* Load parameters for ECDH encryption.
+
+For now, we stick to NIST P-256 because: it's simple and easy to configure;
+it avoids any patent issues that might bite redistributors; despite events in
+the news and concerns over curve choices, we're not cryptographers, we're not
+pretending to be, and this is "good enough" to be better than no support,
+protecting against most adversaries.  Given another year or two, there might
+be sufficient clarity about a "right" way forward to let us make an informed
+decision, instead of a knee-jerk reaction.
+
+Longer-term, we should look at supporting both various named curves and
+external files generated with "openssl ecparam", much as we do for init_dh().
+We should also support "none" as a value, to explicitly avoid initialisation.
+
+Patches welcome.
+
+Arguments:
+  sctx      The current SSL CTX (inbound or outbound)
+  host      connected host, if client; NULL if server
+  errstr    error string pointer
+
+Returns:    TRUE if OK (nothing to set up, or setup worked)
+*/
+
+static BOOL
+init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr)
+{
+#ifdef OPENSSL_NO_ECDH
+return TRUE;
+#else
+
+EC_KEY * ecdh;
+uschar * exp_curve;
+int nid;
+BOOL rv;
+
+if (host)    /* No ECDH setup for clients, only for servers */
+  return TRUE;
+
+# ifndef EXIM_HAVE_ECDH
+DEBUG(D_tls)
+  debug_printf("No OpenSSL API to define ECDH parameters, skipping\n");
+return TRUE;
+# else
+
+if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr))
+  return FALSE;
+if (!exp_curve || !*exp_curve)
+  return TRUE;
+
+/* "auto" needs to be handled carefully.
+ * OpenSSL <  1.0.2: we do not select anything, but fallback to prime256v1
+ * OpenSSL <  1.1.0: we have to call SSL_CTX_set_ecdh_auto
+ *                   (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO)
+ * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection
+ *                   https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b
+ */
+if (Ustrcmp(exp_curve, "auto") == 0)
+  {
+#if OPENSSL_VERSION_NUMBER < 0x10002000L
+  DEBUG(D_tls) debug_printf(
+    "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n");
+  exp_curve = US"prime256v1";
+#else
+# if defined SSL_CTRL_SET_ECDH_AUTO
+  DEBUG(D_tls) debug_printf(
+    "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n");
+  SSL_CTX_set_ecdh_auto(sctx, 1);
+  return TRUE;
+# else
+  DEBUG(D_tls) debug_printf(
+    "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n");
+  return TRUE;
+# endif
+#endif
+  }
+
+DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve);
+if (  (nid = OBJ_sn2nid       (CCS exp_curve)) == NID_undef
+#   ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID
+   && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef
+#   endif
+   )
+  {
+  tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve),
+    host, NULL, errstr);
+  return FALSE;
+  }
+
+if (!(ecdh = EC_KEY_new_by_curve_name(nid)))
+  {
+  tls_error(US"Unable to create ec curve", host, NULL, errstr);
+  return FALSE;
+  }
+
+/* The "tmp" in the name here refers to setting a temporary key
+not to the stability of the interface. */
+
+if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0))
+  tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr);
+else
+  DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve);
+
+EC_KEY_free(ecdh);
+return !rv;
+
+# endif    /*EXIM_HAVE_ECDH*/
+#endif /*OPENSSL_NO_ECDH*/
+}
+
+
+
 /*************************************************
-*        Callback to generate RSA key            *
+*        Expand key and cert file specs          *
 *************************************************/


/*
@@ -518,30 +793,139 @@ return rsa_key;



-/* Extreme debug
-#ifndef DISABLE_OCSP
-void
-x509_store_dump_cert_s_names(X509_STORE * store)
+/* Create and install a selfsigned certificate, for use in server mode */
+
+static int
+tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr)
{
-STACK_OF(X509_OBJECT) * roots= store->objs;
-static uschar name[256];
+X509 * x509 = NULL;
+EVP_PKEY * pkey;
+RSA * rsa;
+X509_NAME * name;
+uschar * where;

-for (int i= 0; i < sk_X509_OBJECT_num(roots); i++)
+where = US"allocating pkey";
+if (!(pkey = EVP_PKEY_new()))
+  goto err;
+
+where = US"allocating cert";
+if (!(x509 = X509_new()))
+  goto err;
+
+where = US"generating pkey";
+if (!(rsa = rsa_callback(NULL, 0, 2048)))
+  goto err;
+
+where = US"assigning pkey";
+if (!EVP_PKEY_assign_RSA(pkey, rsa))
+  goto err;
+
+X509_set_version(x509, 2);                /* N+1 - version 3 */
+ASN1_INTEGER_set(X509_get_serialNumber(x509), 1);
+X509_gmtime_adj(X509_get_notBefore(x509), 0);
+X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60);    /* 1 hour */
+X509_set_pubkey(x509, pkey);
+
+name = X509_get_subject_name(x509);
+X509_NAME_add_entry_by_txt(name, "C",
+              MBSTRING_ASC, CUS "UK", -1, -1, 0);
+X509_NAME_add_entry_by_txt(name, "O",
+              MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0);
+X509_NAME_add_entry_by_txt(name, "CN",
+              MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0);
+X509_set_issuer_name(x509, name);
+
+where = US"signing cert";
+if (!X509_sign(x509, pkey, EVP_md5()))
+  goto err;
+
+where = US"installing selfsign cert";
+if (!SSL_CTX_use_certificate(sctx, x509))
+  goto err;
+
+where = US"installing selfsign key";
+if (!SSL_CTX_use_PrivateKey(sctx, pkey))
+  goto err;
+
+return OK;
+
+err:
+  (void) tls_error(where, NULL, NULL, errstr);
+  if (x509) X509_free(x509);
+  if (pkey) EVP_PKEY_free(pkey);
+  return DEFER;
+}
+
+
+
+
+
+
+
+/*************************************************
+*           Information callback                 *
+*************************************************/
+
+/* The SSL library functions call this from time to time to indicate what they
+are doing. We copy the string to the debugging output when TLS debugging has
+been requested.
+
+Arguments:
+  s         the SSL connection
+  where
+  ret
+
+Returns:    nothing
+*/
+
+static void
+info_callback(SSL *s, int where, int ret)
+{
+DEBUG(D_tls)
   {
-  X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i);
-  if(tmp_obj->type == X509_LU_X509)
-    {
-    X509_NAME * sn = X509_get_subject_name(tmp_obj->data.x509);
-    if (X509_NAME_oneline(sn, CS name, sizeof(name)))
-      {
-      name[sizeof(name)-1] = '\0';
-      debug_printf(" %s\n", name);
-      }
-    }
+  const uschar * str;
+
+  if (where & SSL_ST_CONNECT)
+     str = US"SSL_connect";
+  else if (where & SSL_ST_ACCEPT)
+     str = US"SSL_accept";
+  else
+     str = US"SSL info (undefined)";
+
+  if (where & SSL_CB_LOOP)
+     debug_printf("%s: %s\n", str, SSL_state_string_long(s));
+  else if (where & SSL_CB_ALERT)
+    debug_printf("SSL3 alert %s:%s:%s\n",
+      str = where & SSL_CB_READ ? US"read" : US"write",
+      SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret));
+  else if (where & SSL_CB_EXIT)
+     if (ret == 0)
+    debug_printf("%s: failed in %s\n", str, SSL_state_string_long(s));
+     else if (ret < 0)
+    debug_printf("%s: error in %s\n", str, SSL_state_string_long(s));
+  else if (where & SSL_CB_HANDSHAKE_START)
+     debug_printf("%s: hshake start: %s\n", str, SSL_state_string_long(s));
+  else if (where & SSL_CB_HANDSHAKE_DONE)
+     debug_printf("%s: hshake done: %s\n", str, SSL_state_string_long(s));
   }
 }
+
+#ifdef OPENSSL_HAVE_KEYLOG_CB
+static void
+keylog_callback(const SSL *ssl, const char *line)
+{
+char * filename;
+FILE * fp;
+DEBUG(D_tls) debug_printf("%.200s\n", line);
+if (!(filename = getenv("SSLKEYLOGFILE"))) return;
+if (!(fp = fopen(filename, "a"))) return;
+fprintf(fp, "%s\n", line);
+fclose(fp);
+}
 #endif
-*/
+
+
+



#ifndef DISABLE_EVENT
@@ -553,7 +937,7 @@ uschar * ev;
uschar * yield;
X509 * old_cert;

-ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
+ev = tlsp == &tls_out ? client_static_state->event_action : event_action;
 if (ev)
   {
   DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth);
@@ -660,15 +1044,15 @@ else if (depth != 0)
   {
   DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn);
 #ifndef DISABLE_OCSP
-  if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store)
+  if (tlsp == &tls_out && client_static_state->u_ocsp.client.verify_store)
     {    /* client, wanting stapling  */
     /* Add the server cert's signing chain as the one
     for the verification of the OCSP stapled information. */


-    if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store,
+    if (!X509_STORE_add_cert(client_static_state->u_ocsp.client.verify_store,
                              cert))
       ERR_clear_error();
-    sk_X509_push(client_static_cbinfo->verify_stack, cert);
+    sk_X509_push(client_static_state->verify_stack, cert);
     }
 #endif
 #ifndef DISABLE_EVENT
@@ -681,7 +1065,7 @@ else
   const uschar * verify_cert_hostnames;


   if (  tlsp == &tls_out
-     && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames)))
+     && ((verify_cert_hostnames = client_static_state->verify_cert_hostnames)))
     /* client, wanting hostname check */
     {


@@ -801,15 +1185,15 @@ if (preverify_ok == 1)
   {
   tls_out.dane_verified = TRUE;
 #ifndef DISABLE_OCSP
-  if (client_static_cbinfo->u_ocsp.client.verify_store)
+  if (client_static_state->u_ocsp.client.verify_store)
     {    /* client, wanting stapling  */
     /* Add the server cert's signing chain as the one
     for the verification of the OCSP stapled information. */


-    if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store,
+    if (!X509_STORE_add_cert(client_static_state->u_ocsp.client.verify_store,
                              cert))
       ERR_clear_error();
-    sk_X509_push(client_static_cbinfo->verify_stack, cert);
+    sk_X509_push(client_static_state->verify_stack, cert);
     }
 #endif
   }
@@ -827,836 +1211,999 @@ return preverify_ok;
 #endif    /*SUPPORT_DANE*/



+#ifndef DISABLE_OCSP
 /*************************************************
-*           Information callback                 *
+*       Load OCSP information into state         *
 *************************************************/
+/* Called to load the server OCSP response from the given file into memory, once
+caller has determined this is needed.  Checks validity.  Debugs a message
+if invalid.


-/* The SSL library functions call this from time to time to indicate what they
-are doing. We copy the string to the debugging output when TLS debugging has
-been requested.
+ASSUMES: single response, for single cert.

 Arguments:
-  s         the SSL connection
-  where
-  ret
-
-Returns:    nothing
+  state           various parts of session state
+  filename        the filename putatively holding an OCSP response
+  is_pem      file is PEM format; otherwise is DER
 */


 static void
-info_callback(SSL *s, int where, int ret)
+ocsp_load_response(exim_openssl_state_st * state, const uschar * filename,
+  BOOL is_pem)
 {
+BIO * bio;
+OCSP_RESPONSE * resp;
+OCSP_BASICRESP * basic_response;
+OCSP_SINGLERESP * single_response;
+ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd;
+STACK_OF(X509) * sk;
+unsigned long verify_flags;
+int status, reason, i;
+
 DEBUG(D_tls)
+  debug_printf("tls_ocsp_file (%s)  '%s'\n", is_pem ? "PEM" : "DER", filename);
+
+if (!(bio = BIO_new_file(CS filename, "rb")))
   {
-  const uschar * str;
+  DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n",
+      filename);
+  return;
+  }


-  if (where & SSL_ST_CONNECT)
-     str = US"SSL_connect";
-  else if (where & SSL_ST_ACCEPT)
-     str = US"SSL_accept";
-  else
-     str = US"SSL info (undefined)";
+if (is_pem)
+  {
+  uschar * data, * freep;
+  char * dummy;
+  long len;
+  if (!PEM_read_bio(bio, &dummy, &dummy, &data, &len))
+    {
+    DEBUG(D_tls) debug_printf("Failed to read PEM file \"%s\"\n",
+    filename);
+    return;
+    }
+  freep = data;
+  resp = d2i_OCSP_RESPONSE(NULL, CUSS &data, len);
+  OPENSSL_free(freep);
+  }
+else
+  resp = d2i_OCSP_RESPONSE_bio(bio, NULL);
+BIO_free(bio);


-  if (where & SSL_CB_LOOP)
-     debug_printf("%s: %s\n", str, SSL_state_string_long(s));
-  else if (where & SSL_CB_ALERT)
-    debug_printf("SSL3 alert %s:%s:%s\n",
-      str = where & SSL_CB_READ ? US"read" : US"write",
-      SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret));
-  else if (where & SSL_CB_EXIT)
-     if (ret == 0)
-    debug_printf("%s: failed in %s\n", str, SSL_state_string_long(s));
-     else if (ret < 0)
-    debug_printf("%s: error in %s\n", str, SSL_state_string_long(s));
-  else if (where & SSL_CB_HANDSHAKE_START)
-     debug_printf("%s: hshake start: %s\n", str, SSL_state_string_long(s));
-  else if (where & SSL_CB_HANDSHAKE_DONE)
-     debug_printf("%s: hshake done: %s\n", str, SSL_state_string_long(s));
+if (!resp)
+  {
+  DEBUG(D_tls) debug_printf("Error reading OCSP response.\n");
+  return;
   }
-}


-#ifdef OPENSSL_HAVE_KEYLOG_CB
-static void
-keylog_callback(const SSL *ssl, const char *line)
-{
-char * filename;
-FILE * fp;
-DEBUG(D_tls) debug_printf("%.200s\n", line);
-if (!(filename = getenv("SSLKEYLOGFILE"))) return;
-if (!(fp = fopen(filename, "a"))) return;
-fprintf(fp, "%s\n", line);
-fclose(fp);
-}
+if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL)
+  {
+  DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n",
+      OCSP_response_status_str(status), status);
+  goto bad;
+  }
+
+#ifdef notdef
+  {
+  BIO * bp = BIO_new_fp(debug_file, BIO_NOCLOSE);
+  OCSP_RESPONSE_print(bp, resp, 0);  /* extreme debug: stapling content */
+  BIO_free(bp);
+  }
 #endif


+if (!(basic_response = OCSP_response_get1_basic(resp)))
+  {
+  DEBUG(D_tls)
+    debug_printf("OCSP response parse error: unable to extract basic response.\n");
+  goto bad;
+  }


-#ifndef DISABLE_TLS_RESUME
-/* Manage the keysets used for encrypting the session tickets, on the server. */
+sk = state->verify_stack;
+verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */

-typedef struct {            /* Session ticket encryption key */
-  uschar     name[16];
+/* May need to expose ability to adjust those flags?
+OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT
+OCSP_TRUSTOTHER OCSP_NOINTERN */


-  const EVP_CIPHER *    aes_cipher;
-  uschar        aes_key[32];    /* size needed depends on cipher. aes_128 implies 128/8 = 16? */
-  const EVP_MD *    hmac_hash;
-  uschar        hmac_key[16];
-  time_t        renew;
-  time_t        expire;
-} exim_stek;
+/* This does a full verify on the OCSP proof before we load it for serving
+up; possibly overkill - just date-checks might be nice enough.


-static exim_stek exim_tk;    /* current key */
-static exim_stek exim_tk_old;    /* previous key */
+OCSP_basic_verify takes a "store" arg, but does not
+use it for the chain verification, which is all we do
+when OCSP_NOVERIFY is set.  The content from the wire
+"basic_response" and a cert-stack "sk" are all that is used.


-static void
-tk_init(void)
-{
-time_t t = time(NULL);
+We have a stack, loaded in setup_certs() if tls_verify_certificates
+was a file (not a directory, or "system"). It is unfortunate we
+cannot used the connection context store, as that would neatly
+handle the "system" case too, but there seems to be no library
+function for getting a stack from a store.
+[ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ]
+We do not free the stack since it could be needed a second time for
+SNI handling.

-if (exim_tk.name[0])
+Separately we might try to replace using OCSP_basic_verify() - which seems to not
+be a public interface into the OpenSSL library (there's no manual entry) -
+But what with?  We also use OCSP_basic_verify in the client stapling callback.
+And there we NEED it; we must verify that status... unless the
+library does it for us anyway?  */
+
+if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0)
   {
-  if (exim_tk.renew >= t) return;
-  exim_tk_old = exim_tk;
+  DEBUG(D_tls)
+    {
+    ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring));
+    debug_printf("OCSP response verify failure: %s\n", US ssl_errstring);
+    }
+  goto bad;
   }


-if (f.running_in_test_harness) ssl_session_timeout = 6;
+/* Here's the simplifying assumption: there's only one response, for the
+one certificate we use, and nothing for anything else in a chain. If this
+proves false, we need to extract a cert id from our issued cert
+(tls_certificate) and use that for OCSP_resp_find_status() (which finds the
+right cert in the stack and then calls OCSP_single_get0_status()).

-DEBUG(D_tls) debug_printf("OpenSSL: %s STEK\n", exim_tk.name[0] ? "rotating" : "creating");
-if (RAND_bytes(exim_tk.aes_key, sizeof(exim_tk.aes_key)) <= 0) return;
-if (RAND_bytes(exim_tk.hmac_key, sizeof(exim_tk.hmac_key)) <= 0) return;
-if (RAND_bytes(exim_tk.name+1, sizeof(exim_tk.name)-1) <= 0) return;
+I'm hoping to avoid reworking a bunch more of how we handle state here.

-exim_tk.name[0] = 'E';
-exim_tk.aes_cipher = EVP_aes_256_cbc();
-exim_tk.hmac_hash = EVP_sha256();
-exim_tk.expire = t + ssl_session_timeout;
-exim_tk.renew = t + ssl_session_timeout/2;
+XXX that will change when we add support for (TLS1.3) whole-chain stapling
+*/
+
+if (!(single_response = OCSP_resp_get0(basic_response, 0)))
+  {
+  DEBUG(D_tls)
+    debug_printf("Unable to get first response from OCSP basic response.\n");
+  goto bad;
+  }
+
+status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd);
+if (status != V_OCSP_CERTSTATUS_GOOD)
+  {
+  DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n",
+      OCSP_cert_status_str(status), status,
+      OCSP_crl_reason_str(reason), reason);
+  goto bad;
+  }
+
+if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
+  {
+  DEBUG(D_tls) debug_printf("OCSP status invalid times.\n");
+  goto bad;
+  }
+
+supply_response:
+  /* Add the resp to the list used by tls_server_stapling_cb() */
+  {
+  ocsp_resplist ** op = &state->u_ocsp.server.olist, * oentry;
+  while (oentry = *op)
+    op = &oentry->next;
+  *op = oentry = store_get(sizeof(ocsp_resplist), FALSE);
+  oentry->next = NULL;
+  oentry->resp = resp;
+  }
+return;
+
+bad:
+  if (f.running_in_test_harness)
+    {
+    extern char ** environ;
+    if (environ) for (uschar ** p = USS environ; *p; p++)
+      if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
+    {
+    DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n");
+    goto supply_response;
+    }
+    }
+return;
 }


-static exim_stek *
-tk_current(void)
+
+static void
+ocsp_free_response_list(exim_openssl_state_st * cbinfo)
 {
-if (!exim_tk.name[0]) return NULL;
-return &exim_tk;
+for (ocsp_resplist * olist = cbinfo->u_ocsp.server.olist; olist;
+     olist = olist->next)
+  OCSP_RESPONSE_free(olist->resp);
+cbinfo->u_ocsp.server.olist = NULL;
 }
+#endif    /*!DISABLE_OCSP*/


-static exim_stek *
-tk_find(const uschar * name)
+
+
+
+
+static int
+tls_add_certfile(SSL_CTX * sctx, exim_openssl_state_st * cbinfo, uschar * file,
+  uschar ** errstr)
 {
-return memcmp(name, exim_tk.name, sizeof(exim_tk.name)) == 0 ? &exim_tk
-  : memcmp(name, exim_tk_old.name, sizeof(exim_tk_old.name)) == 0 ? &exim_tk_old
-  : NULL;
+DEBUG(D_tls) debug_printf("tls_certificate file '%s'\n", file);
+if (!SSL_CTX_use_certificate_chain_file(sctx, CS file))
+  return tls_error(string_sprintf(
+    "SSL_CTX_use_certificate_chain_file file=%s", file),
+      cbinfo->host, NULL, errstr);
+return 0;
 }


-/* Callback for session tickets, on server */
 static int
-ticket_key_callback(SSL * ssl, uschar key_name[16],
-  uschar * iv, EVP_CIPHER_CTX * ctx, HMAC_CTX * hctx, int enc)
+tls_add_pkeyfile(SSL_CTX * sctx, exim_openssl_state_st * cbinfo, uschar * file,
+  uschar ** errstr)
 {
-tls_support * tlsp = server_static_cbinfo->tlsp;
-exim_stek * key;
+DEBUG(D_tls) debug_printf("tls_privatekey file  '%s'\n", file);
+if (!SSL_CTX_use_PrivateKey_file(sctx, CS file, SSL_FILETYPE_PEM))
+  return tls_error(string_sprintf(
+    "SSL_CTX_use_PrivateKey_file file=%s", file), cbinfo->host, NULL, errstr);
+return 0;
+}


-if (enc)
- {
- DEBUG(D_tls) debug_printf("ticket_key_callback: create new session\n");
- tlsp->resumption |= RESUME_CLIENT_REQUESTED;

-  if (RAND_bytes(iv, EVP_MAX_IV_LENGTH) <= 0)
-    return -1; /* insufficient random */


-  if (!(key = tk_current()))    /* current key doesn't exist or isn't valid */
-     return 0;            /* key couldn't be created */
-  memcpy(key_name, key->name, 16);
-  DEBUG(D_tls) debug_printf("STEK expire " TIME_T_FMT "\n", key->expire - time(NULL));


-  /*XXX will want these dependent on the ssl session strength */
-  HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key),
-        key->hmac_hash, NULL);
-  EVP_EncryptInit_ex(ctx, key->aes_cipher, NULL, key->aes_key, iv);
+/* Called once during tls_init and possibly again during TLS setup, for a
+new context, if Server Name Indication was used and tls_sni was seen in
+the certificate string.


-  DEBUG(D_tls) debug_printf("ticket created\n");
-  return 1;
+Arguments:
+  sctx            the SSL_CTX* to update
+  state           various parts of session state
+  errstr      error string pointer
+
+Returns:          OK/DEFER/FAIL
+*/
+
+static int
+tls_expand_session_files(SSL_CTX * sctx, exim_openssl_state_st * state,
+  uschar ** errstr)
+{
+uschar * expanded;
+
+if (!state->certificate)
+  {
+  if (!state->is_server)        /* client */
+    return OK;
+                    /* server */
+  if (tls_install_selfsign(sctx, errstr) != OK)
+    return DEFER;
   }
 else
   {
-  time_t now = time(NULL);
+  int err;


-  DEBUG(D_tls) debug_printf("ticket_key_callback: retrieve session\n");
-  tlsp->resumption |= RESUME_CLIENT_SUGGESTED;
+  if ( !reexpand_tls_files_for_sni
+     && (  Ustrstr(state->certificate, US"tls_sni")
+    || Ustrstr(state->certificate, US"tls_in_sni")
+    || Ustrstr(state->certificate, US"tls_out_sni")
+     )  )
+    reexpand_tls_files_for_sni = TRUE;


-  if (!(key = tk_find(key_name)) || key->expire < now)
-    {
-    DEBUG(D_tls)
+  if (!expand_check(state->certificate, US"tls_certificate", &expanded, errstr))
+    return DEFER;
+
+  if (expanded)
+    if (state->is_server)
       {
-      debug_printf("ticket not usable (%s)\n", key ? "expired" : "not found");
-      if (key) debug_printf("STEK expire " TIME_T_FMT "\n", key->expire - now);
+      const uschar * file_list = expanded;
+      int sep = 0;
+      uschar * file;
+#ifndef DISABLE_OCSP
+      const uschar * olist = state->u_ocsp.server.file;
+      int osep = 0;
+      uschar * ofile;
+      BOOL fmt_pem = FALSE;
+
+      if (olist)
+    if (!expand_check(olist, US"tls_ocsp_file", USS &olist, errstr))
+      return DEFER;
+      if (olist && !*olist)
+    olist = NULL;
+
+      if (  state->u_ocsp.server.file_expanded && olist
+     && (Ustrcmp(olist, state->u_ocsp.server.file_expanded) == 0))
+    {
+    DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n");
+    olist = NULL;
+    }
+      else
+    {
+    ocsp_free_response_list(state);
+    state->u_ocsp.server.file_expanded = olist;
+    }
+#endif
+
+      while (file = string_nextinlist(&file_list, &sep, NULL, 0))
+    {
+    if ((err = tls_add_certfile(sctx, state, file, errstr)))
+      return err;
+
+#ifndef DISABLE_OCSP
+    if (olist)
+      if ((ofile = string_nextinlist(&olist, &osep, NULL, 0)))
+        {
+        if (Ustrncmp(ofile, US"PEM ", 4) == 0)
+          {
+          fmt_pem = TRUE;
+          ofile += 4;
+          }
+        else if (Ustrncmp(ofile, US"DER ", 4) == 0)
+          {
+          fmt_pem = FALSE;
+          ofile += 4;
+          }
+        ocsp_load_response(state, ofile, fmt_pem);
+        }
+      else
+        DEBUG(D_tls) debug_printf("ran out of ocsp file list\n");
+#endif
+    }
       }
-    return 0;
-    }
+    else    /* would there ever be a need for multiple client certs? */
+      if ((err = tls_add_certfile(sctx, state, expanded, errstr)))
+    return err;


-  HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key),
-        key->hmac_hash, NULL);
-  EVP_DecryptInit_ex(ctx, key->aes_cipher, NULL, key->aes_key, iv);
+  if (  state->privatekey
+     && !expand_check(state->privatekey, US"tls_privatekey", &expanded, errstr))
+    return DEFER;


- DEBUG(D_tls) debug_printf("ticket usable, STEK expire " TIME_T_FMT "\n", key->expire - now);
+ /* If expansion was forced to fail, key_expanded will be NULL. If the result
+ of the expansion is an empty string, ignore it also, and assume the private
+ key is in the same file as the certificate. */

-  /* The ticket lifetime and renewal are the same as the STEK lifetime and
-  renewal, which is overenthusiastic.  A factor of, say, 3x longer STEK would
-  be better.  To do that we'd have to encode ticket lifetime in the name as
-  we don't yet see the restored session.  Could check posthandshake for TLS1.3
-  and trigger a new ticket then, but cannot do that for TLS1.2 */
-  return key->renew < now ? 2 : 1;
+  if (expanded && *expanded)
+    if (state->is_server)
+      {
+      const uschar * file_list = expanded;
+      int sep = 0;
+      uschar * file;
+
+      while (file = string_nextinlist(&file_list, &sep, NULL, 0))
+    if ((err = tls_add_pkeyfile(sctx, state, file, errstr)))
+      return err;
+      }
+    else    /* would there ever be a need for multiple client certs? */
+      if ((err = tls_add_pkeyfile(sctx, state, expanded, errstr)))
+    return err;
   }
+
+return OK;
 }
-#endif




-/*************************************************
-*                Initialize for DH               *
-*************************************************/


-/* If dhparam is set, expand it, and load up the parameters for DH encryption.
+/**************************************************
+* One-time init credentials for server and client *
+**************************************************/

-Arguments:
-  sctx      The current SSL CTX (inbound or outbound)
-  dhparam   DH parameter file or fixed parameter identity string
-  host      connected host, if client; NULL if server
-  errstr    error string pointer


-Returns:    TRUE if OK (nothing to set up, or setup worked)
-*/
+#ifdef gnutls
+static void
+creds_basic_init(gnutls_certificate_credentials_t x509_cred, BOOL server)
+{
+}
+#endif


-static BOOL
-init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr)
+static int
+creds_load_server_certs(/*exim_gnutls_state_st * state,*/ const uschar * cert,
+ const uschar * pkey, const uschar * ocsp, uschar ** errstr)
{
-BIO *bio;
-DH *dh;
-uschar *dhexpanded;
-const char *pem;
-int dh_bitsize;
+#ifdef gnutls
+const uschar * clist = cert;
+const uschar * klist = pkey;
+const uschar * olist;
+int csep = 0, ksep = 0, osep = 0, cnt = 0, rc;
+uschar * cfile, * kfile, * ofile;
+#ifndef DISABLE_OCSP
+# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
+gnutls_x509_crt_fmt_t ocsp_fmt = GNUTLS_X509_FMT_DER;
+# endif

-if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr))
- return FALSE;
+if (!expand_check(ocsp, US"tls_ocsp_file", &ofile, errstr))
+ return DEFER;
+olist = ofile;
+#endif

-if (!dhexpanded || !*dhexpanded)
-  bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1);
-else if (dhexpanded[0] == '/')
-  {
-  if (!(bio = BIO_new_file(CS dhexpanded, "r")))
-    {
-    tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
-          host, US strerror(errno), errstr);
-    return FALSE;
-    }
-  }
-else
-  {
-  if (Ustrcmp(dhexpanded, "none") == 0)
-    {
-    DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
-    return TRUE;
-    }
+while (cfile = string_nextinlist(&clist, &csep, NULL, 0))


-  if (!(pem = std_dh_prime_named(dhexpanded)))
+  if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0)))
+    return tls_error(US"cert/key setup: out of keys", NULL, NULL, errstr);
+  else if ((rc = tls_add_certfile(state, NULL, cfile, kfile, errstr)) > 0)
+    return rc;
+  else
     {
-    tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded),
-        host, US strerror(errno), errstr);
-    return FALSE;
+    int gnutls_cert_index = -rc;
+    DEBUG(D_tls) debug_printf("TLS: cert/key %d %s registered\n",
+                  gnutls_cert_index, cfile);
+
+#ifndef DISABLE_OCSP
+    if (ocsp)
+      {
+      /* Set the OCSP stapling server info */
+      if (gnutls_buggy_ocsp)
+    {
+    DEBUG(D_tls)
+      debug_printf("GnuTLS library is buggy for OCSP; avoiding\n");
+    }
+      else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0)))
+    {
+    DEBUG(D_tls) debug_printf("OCSP response file %d  = %s\n",
+                  gnutls_cert_index, ofile);
+# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE
+    if (Ustrncmp(ofile, US"PEM ", 4) == 0)
+      {
+      ocsp_fmt = GNUTLS_X509_FMT_PEM;
+      ofile += 4;
+      }
+    else if (Ustrncmp(ofile, US"DER ", 4) == 0)
+      {
+      ocsp_fmt = GNUTLS_X509_FMT_DER;
+      ofile += 4;
+      }
+
+    if  ((rc = gnutls_certificate_set_ocsp_status_request_file2(
+          state->lib_state.x509_cred, CCS ofile, gnutls_cert_index,
+          ocsp_fmt)) < 0)
+      return tls_error_gnu(
+          US"gnutls_certificate_set_ocsp_status_request_file2",
+          rc, NULL, errstr);
+    DEBUG(D_tls)
+      debug_printf(" %d response%s loaded\n", rc, rc>1 ? "s":"");
+
+    /* Arrange callbacks for OCSP request observability */
+
+    if (state->session)
+      gnutls_handshake_set_hook_function(state->session,
+        GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb);
+    else
+      state->lib_state.ocsp_hook = TRUE;
+
+
+# else
+#  if defined(SUPPORT_SRV_OCSP_STACK)
+    if ((rc = gnutls_certificate_set_ocsp_status_request_function2(
+             state->lib_state.x509_cred, gnutls_cert_index,
+             server_ocsp_stapling_cb, ofile)))
+        return tls_error_gnu(
+          US"gnutls_certificate_set_ocsp_status_request_function2",
+          rc, NULL, errstr);
+    else
+#  endif
+      {
+      if (cnt++ > 0)
+        {
+        DEBUG(D_tls)
+          debug_printf("oops; multiple OCSP files not supported\n");
+        break;
+        }
+      gnutls_certificate_set_ocsp_status_request_function(
+        state->lib_state.x509_cred, server_ocsp_stapling_cb, ofile);
+      }
+# endif    /* SUPPORT_GNUTLS_EXT_RAW_PARSE */
+    }
+      else
+    DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n");
+      }
+#endif /* DISABLE_OCSP */
     }
-  bio = BIO_new_mem_buf(CS pem, -1);
-  }
+return 0;
+#endif /*gnutls*/
+}


-if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)))
-  {
-  BIO_free(bio);
-  tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded),
-      host, NULL, errstr);
-  return FALSE;
-  }
+static int
+creds_load_client_certs(/*exim_gnutls_state_st * state,*/ const host_item * host,
+  const uschar * cert, const uschar * pkey, uschar ** errstr)
+{
+return 0;
+}


-/* note: our default limit of 2236 is not a multiple of 8; the limit comes from
- * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with
- * 2236. But older OpenSSL can only report in bytes (octets), not bits.
- * If someone wants to dance at the edge, then they can raise the limit or use
- * current libraries. */
-#ifdef EXIM_HAVE_OPENSSL_DH_BITS
-/* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022
- * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */
-dh_bitsize = DH_bits(dh);
-#else
-dh_bitsize = 8 * DH_size(dh);
-#endif
+static int
+creds_load_cabundle(/*exim_gnutls_state_st * state,*/ const uschar * bundle,
+ const host_item * host, uschar ** errstr)
+{
+#ifdef gnutls
+int cert_count;
+struct stat statbuf;

-/* Even if it is larger, we silently return success rather than cause things
- * to fail out, so that a too-large DH will not knock out all TLS; it's a
- * debatable choice. */
-if (dh_bitsize > tls_dh_max_bits)
-  {
-  DEBUG(D_tls)
-    debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n",
-        dh_bitsize, tls_dh_max_bits);
-  }
+#ifdef SUPPORT_SYSDEFAULT_CABUNDLE
+if (Ustrcmp(bundle, "system") == 0 || Ustrncmp(bundle, "system,", 7) == 0)
+  cert_count = gnutls_certificate_set_x509_system_trust(state->lib_state.x509_cred);
 else
+#endif
   {
-  SSL_CTX_set_tmp_dh(sctx, dh);
-  DEBUG(D_tls)
-    debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n",
-      dhexpanded ? dhexpanded : US"default", dh_bitsize);
-  }
+  if (Ustat(bundle, &statbuf) < 0)
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC, "could not stat '%s' "
+    "(tls_verify_certificates): %s", bundle, strerror(errno));
+    return DEFER;
+    }


-DH_free(dh);
-BIO_free(bio);
+#ifndef SUPPORT_CA_DIR
+  /* The test suite passes in /dev/null; we could check for that path explicitly,
+  but who knows if someone has some weird FIFO which always dumps some certs, or
+  other weirdness.  The thing we really want to check is that it's not a
+  directory, since while OpenSSL supports that, GnuTLS does not.
+  So s/!S_ISREG/S_ISDIR/ and change some messaging ... */
+  if (S_ISDIR(statbuf.st_mode))
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC,
+    "tls_verify_certificates \"%s\" is a directory", bundle);
+    return DEFER;
+    }
+#endif


-return TRUE;
-}
+  DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n",
+      bundle, statbuf.st_size);


+  if (statbuf.st_size == 0)
+    {
+    DEBUG(D_tls)
+      debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n");
+    return OK;
+    }


+ cert_count =

+#ifdef SUPPORT_CA_DIR
+    (statbuf.st_mode & S_IFMT) == S_IFDIR
+    ?
+    gnutls_certificate_set_x509_trust_dir(state->lib_state.x509_cred,
+      CS bundle, GNUTLS_X509_FMT_PEM)
+    :
+#endif
+    gnutls_certificate_set_x509_trust_file(state->lib_state.x509_cred,
+      CS bundle, GNUTLS_X509_FMT_PEM);


-/*************************************************
-*               Initialize for ECDH              *
-*************************************************/
+#ifdef SUPPORT_CA_DIR
+  /* Mimic the behaviour with OpenSSL of not advertising a usable-cert list
+  when using the directory-of-certs config model. */


-/* Load parameters for ECDH encryption.
+  if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
+    if (state->session)
+      gnutls_certificate_send_x509_rdn_sequence(state->session, 1);
+    else
+      state->lib_state.ca_rdn_emulate = TRUE;
+#endif
+  }


-For now, we stick to NIST P-256 because: it's simple and easy to configure;
-it avoids any patent issues that might bite redistributors; despite events in
-the news and concerns over curve choices, we're not cryptographers, we're not
-pretending to be, and this is "good enough" to be better than no support,
-protecting against most adversaries. Given another year or two, there might
-be sufficient clarity about a "right" way forward to let us make an informed
-decision, instead of a knee-jerk reaction.
+if (cert_count < 0)
+ return tls_error_gnu(US"setting certificate trust", cert_count, host, errstr);
+DEBUG(D_tls)
+ debug_printf("Added %d certificate authorities\n", cert_count);

-Longer-term, we should look at supporting both various named curves and
-external files generated with "openssl ecparam", much as we do for init_dh().
-We should also support "none" as a value, to explicitly avoid initialisation.
+#endif /*gnutls*/
+return OK;
+}

-Patches welcome.

-Arguments:
-  sctx      The current SSL CTX (inbound or outbound)
-  host      connected host, if client; NULL if server
-  errstr    error string pointer
+static int
+creds_load_crl(/*exim_gnutls_state_st * state,*/ const uschar * crl, uschar ** errstr)
+{
+return FAIL;
+}


-Returns:    TRUE if OK (nothing to set up, or setup worked)
-*/


-static BOOL
-init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr)
+static int
+creds_load_pristring(/*exim_gnutls_state_st * state,*/ const uschar * p,
+ const char ** errpos)
{
-#ifdef OPENSSL_NO_ECDH
-return TRUE;
-#else
-
-EC_KEY * ecdh;
-uschar * exp_curve;
-int nid;
-BOOL rv;
+return FAIL;
+}

-if (host)    /* No ECDH setup for clients, only for servers */
-  return TRUE;
+static int
+server_load_ciphers(SSL_CTX * ctx, exim_openssl_state_st * state,
+  uschar * ciphers, uschar ** errstr)
+{
+for (uschar * s = ciphers; *s; s++ ) if (*s == '_') *s = '-';
+DEBUG(D_tls) debug_printf("required ciphers: %s\n", ciphers);
+if (!SSL_CTX_set_cipher_list(ctx, CS ciphers))
+  return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr);
+state->server_cipher_list = ciphers;
+return OK;
+}


-# ifndef EXIM_HAVE_ECDH
-DEBUG(D_tls)
- debug_printf("No OpenSSL API to define ECDH parameters, skipping\n");
-return TRUE;
-# else

-if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr))
- return FALSE;
-if (!exp_curve || !*exp_curve)
- return TRUE;

-/* "auto" needs to be handled carefully.
- * OpenSSL <  1.0.2: we do not select anything, but fallback to prime256v1
- * OpenSSL <  1.1.0: we have to call SSL_CTX_set_ecdh_auto
- *                   (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO)
- * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection
- *                   https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b
- */
-if (Ustrcmp(exp_curve, "auto") == 0)
-  {
-#if OPENSSL_VERSION_NUMBER < 0x10002000L
-  DEBUG(D_tls) debug_printf(
-    "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n");
-  exp_curve = US"prime256v1";
+static int
+lib_ctx_new(SSL_CTX ** ctxp, host_item * host, uschar ** errstr)
+{
+SSL_CTX * ctx;
+#ifdef EXIM_HAVE_OPENSSL_TLS_METHOD
+if (!(ctx = SSL_CTX_new(host ? TLS_client_method() : TLS_server_method())))
 #else
-# if defined SSL_CTRL_SET_ECDH_AUTO
-  DEBUG(D_tls) debug_printf(
-    "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n");
-  SSL_CTX_set_ecdh_auto(sctx, 1);
-  return TRUE;
-# else
-  DEBUG(D_tls) debug_printf(
-    "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n");
-  return TRUE;
-# endif
+if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method())))
 #endif
-  }
+  return tls_error(US"SSL_CTX_new", host, NULL, errstr);


-DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve);
-if (  (nid = OBJ_sn2nid       (CCS exp_curve)) == NID_undef
-#   ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID
-   && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef
-#   endif
-   )
-  {
-  tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve),
-    host, NULL, errstr);
-  return FALSE;
-  }
+/* Set up the information callback, which outputs if debugging is at a suitable
+level. */


-if (!(ecdh = EC_KEY_new_by_curve_name(nid)))
+DEBUG(D_tls)
{
- tls_error(US"Unable to create ec curve", host, NULL, errstr);
- return FALSE;
+ SSL_CTX_set_info_callback(ctx, (void (*)())info_callback);
+#if defined(EXIM_HAVE_OPESSL_TRACE) && !defined(OPENSSL_NO_SSL_TRACE)
+ /* this needs a debug build of OpenSSL */
+ SSL_CTX_set_msg_callback(ctx, (void (*)())SSL_trace);
+#endif
+#ifdef OPENSSL_HAVE_KEYLOG_CB
+ SSL_CTX_set_keylog_callback(ctx, (void (*)())keylog_callback);
+#endif
}

-/* The "tmp" in the name here refers to setting a temporary key
-not to the stability of the interface. */
-
-if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0))
-  tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr);
-else
-  DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve);
-
-EC_KEY_free(ecdh);
-return !rv;
-
-# endif    /*EXIM_HAVE_ECDH*/
-#endif /*OPENSSL_NO_ECDH*/
+/* Automatically re-try reads/writes after renegotiation. */
+(void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
+*ctxp = ctx;
+return OK;
 }



-
-
-#ifndef DISABLE_OCSP
-/*************************************************
-*       Load OCSP information into state         *
-*************************************************/
-/* Called to load the server OCSP response from the given file into memory, once
-caller has determined this is needed.  Checks validity.  Debugs a message
-if invalid.
-
-ASSUMES: single response, for single cert.
-
-Arguments:
-  sctx            the SSL_CTX* to update
-  cbinfo          various parts of session state
-  filename        the filename putatively holding an OCSP response
-  is_pem      file is PEM format; otherwise is DER
-
-*/
-
 static void
-ocsp_load_response(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo,
-  const uschar * filename, BOOL is_pem)
+tls_server_creds_init(void)
 {
-BIO * bio;
-OCSP_RESPONSE * resp;
-OCSP_BASICRESP * basic_response;
-OCSP_SINGLERESP * single_response;
-ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd;
-STACK_OF(X509) * sk;
-unsigned long verify_flags;
-int status, reason, i;
-
-DEBUG(D_tls)
-  debug_printf("tls_ocsp_file (%s)  '%s'\n", is_pem ? "PEM" : "DER", filename);
+SSL_CTX * ctx;
+uschar * dummy_errstr;


-if (!(bio = BIO_new_file(CS filename, "rb")))
-  {
-  DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n",
-      filename);
-  return;
-  }
+tls_openssl_init();


-if (is_pem)
-  {
-  uschar * data, * freep;
-  char * dummy;
-  long len;
-  if (!PEM_read_bio(bio, &dummy, &dummy, &data, &len))
-    {
-    DEBUG(D_tls) debug_printf("Failed to read PEM file \"%s\"\n",
-    filename);
-    return;
-    }
-debug_printf("read pem file\n");
-  freep = data;
-  resp = d2i_OCSP_RESPONSE(NULL, CUSS &data, len);
-  OPENSSL_free(freep);
-  }
-else
-  resp = d2i_OCSP_RESPONSE_bio(bio, NULL);
-BIO_free(bio);
+state_server.lib_state = null_tls_preload;


-if (!resp)
- {
- DEBUG(D_tls) debug_printf("Error reading OCSP response.\n");
+if (lib_ctx_new(&ctx, NULL, &dummy_errstr) != OK)
return;
- }
+state_server.lib_state.lib_ctx = ctx;

-if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL)
-  {
-  DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n",
-      OCSP_response_status_str(status), status);
-  goto bad;
-  }
+/* Preload DH params and EC curve */


-#ifdef notdef
+if (opt_unset_or_noexpand(tls_dhparam))
   {
-  BIO * bp = BIO_new_fp(debug_file, BIO_NOCLOSE);
-  OCSP_RESPONSE_print(bp, resp, 0);  /* extreme debug: stapling content */
-  BIO_free(bp);
+  DEBUG(D_tls) debug_printf("TLS: preloading DH params for server\n");
+  if (init_dh(ctx, tls_dhparam, NULL, &dummy_errstr))
+    state_server.lib_state.dh = TRUE;
   }
-#endif
-
-if (!(basic_response = OCSP_response_get1_basic(resp)))
+if (opt_unset_or_noexpand(tls_eccurve))
   {
-  DEBUG(D_tls)
-    debug_printf("OCSP response parse error: unable to extract basic response.\n");
-  goto bad;
+  DEBUG(D_tls) debug_printf("TLS: preloading ECDH curve for server\n");
+  if (init_ecdh(ctx, NULL, &dummy_errstr))
+    state_server.lib_state.ecdh = TRUE;
   }


-sk = cbinfo->verify_stack;
-verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */
+#ifdef EXIM_HAVE_INOTIFY
+/* If we can, preload the server-side cert, key and ocsp */

-/* May need to expose ability to adjust those flags?
-OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT
-OCSP_TRUSTOTHER OCSP_NOINTERN */
+if ( opt_set_and_noexpand(tls_certificate)
+ && opt_unset_or_noexpand(tls_privatekey)
+ && opt_unset_or_noexpand(tls_ocsp_file))
+ {
+ /* Set watches on the filenames. The implementation does de-duplication
+ so we can just blindly do them all.
+ */

-/* This does a full verify on the OCSP proof before we load it for serving
-up; possibly overkill - just date-checks might be nice enough.
+  if (  tls_set_watch(tls_certificate, TRUE)
+     && tls_set_watch(tls_privatekey, TRUE)
+     && tls_set_watch(tls_ocsp_file, TRUE)
+     )
+    {
+    state_server.certificate = tls_certificate;
+    state_server.privatekey = tls_privatekey;
+#ifndef DISABLE_OCSP
+    state_server.u_ocsp.server.file = tls_ocsp_file;
+#endif


-OCSP_basic_verify takes a "store" arg, but does not
-use it for the chain verification, which is all we do
-when OCSP_NOVERIFY is set.  The content from the wire
-"basic_response" and a cert-stack "sk" are all that is used.
+    DEBUG(D_tls) debug_printf("TLS: preloading server certs\n");
+    if (tls_expand_session_files(ctx, &state_server, &dummy_errstr) == OK)
+      state_server.lib_state.conn_certs = TRUE;
+    }
+  }
+else
+  DEBUG(D_tls) debug_printf("TLS: not preloading server certs\n");


-We have a stack, loaded in setup_certs() if tls_verify_certificates
-was a file (not a directory, or "system"). It is unfortunate we
-cannot used the connection context store, as that would neatly
-handle the "system" case too, but there seems to be no library
-function for getting a stack from a store.
-[ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ]
-We do not free the stack since it could be needed a second time for
-SNI handling.

-Separately we might try to replace using OCSP_basic_verify() - which seems to not
-be a public interface into the OpenSSL library (there's no manual entry) -
-But what with? We also use OCSP_basic_verify in the client stapling callback.
-And there we NEED it; we must verify that status... unless the
-library does it for us anyway? */
+/* If we can, preload the Authorities for checking client certs against.
+Actual choice to do verify is made (tls_{,try_}verify_hosts)
+at TLS conn startup */

-if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0)
+if (  opt_set_and_noexpand(tls_verify_certificates)
+   && opt_unset_or_noexpand(tls_crl))
   {
-  DEBUG(D_tls)
+  /* Watch the default dir also as they are always included */
+
+  if (  tls_set_watch(CUS X509_get_default_cert_file(), FALSE)
+     && tls_set_watch(tls_verify_certificates, FALSE)
+     && tls_set_watch(tls_crl, FALSE))
     {
-    ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring));
-    debug_printf("OCSP response verify failure: %s\n", US ssl_errstring);
+    DEBUG(D_tls) debug_printf("TLS: preloading CA bundle for server\n");
+
+    if (setup_certs(ctx, tls_verify_certificates, tls_crl, NULL, &dummy_errstr)
+    == OK)
+      state_server.lib_state.cabundle = TRUE;
     }
-  goto bad;
   }
+else
+  DEBUG(D_tls) debug_printf("TLS: not preloading CA bundle for server\n");
+#endif    /* EXIM_HAVE_INOTIFY */


-/* Here's the simplifying assumption: there's only one response, for the
-one certificate we use, and nothing for anything else in a chain. If this
-proves false, we need to extract a cert id from our issued cert
-(tls_certificate) and use that for OCSP_resp_find_status() (which finds the
-right cert in the stack and then calls OCSP_single_get0_status()).
-
-I'm hoping to avoid reworking a bunch more of how we handle state here.

-XXX that will change when we add support for (TLS1.3) whole-chain stapling
-*/
+/* If we can, preload the ciphers control string */

-if (!(single_response = OCSP_resp_get0(basic_response, 0)))
+if (opt_set_and_noexpand(tls_require_ciphers))
   {
-  DEBUG(D_tls)
-    debug_printf("Unable to get first response from OCSP basic response.\n");
-  goto bad;
+  DEBUG(D_tls) debug_printf("TLS: preloading cipher list for server\n");
+  if (server_load_ciphers(ctx, &state_server, tls_require_ciphers,
+              &dummy_errstr) == OK)
+    state_server.lib_state.pri_string = TRUE;
   }
+else
+  DEBUG(D_tls) debug_printf("TLS: not preloading cipher list for server\n");
+}


-status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd);
-if (status != V_OCSP_CERTSTATUS_GOOD)
+
+
+
+/* Preload whatever creds are static, onto a transport.  The client can then
+just copy the pointer as it starts up.
+Called from the daemon after a cache-invalidate with watch set; called from
+a queue-run startup with watch clear. */
+
+static void
+tls_client_creds_init(transport_instance * t, BOOL watch)
+{
+smtp_transport_options_block * ob = t->options_block;
+exim_openssl_state_st tpt_dummy_state;
+host_item * dummy_host = (host_item *)1;
+uschar * dummy_errstr;
+SSL_CTX * ctx;
+
+tls_openssl_init();
+
+ob->tls_preload = null_tls_preload;
+if (lib_ctx_new(&ctx, dummy_host, &dummy_errstr) != OK)
+  return;
+ob->tls_preload.lib_ctx = ctx;
+
+tpt_dummy_state.lib_state = ob->tls_preload;
+
+if (opt_unset_or_noexpand(tls_dhparam))
   {
-  DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n",
-      OCSP_cert_status_str(status), status,
-      OCSP_crl_reason_str(reason), reason);
-  goto bad;
+  DEBUG(D_tls) debug_printf("TLS: preloading DH params for transport '%s'\n", t->name);
+  if (init_dh(ctx, tls_dhparam, NULL, &dummy_errstr))
+    ob->tls_preload.dh = TRUE;
   }
-
-if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
+if (opt_unset_or_noexpand(tls_eccurve))
   {
-  DEBUG(D_tls) debug_printf("OCSP status invalid times.\n");
-  goto bad;
+  DEBUG(D_tls) debug_printf("TLS: preloading ECDH curve for transport '%s'\n", t->name);
+  if (init_ecdh(ctx, NULL, &dummy_errstr))
+    ob->tls_preload.ecdh = TRUE;
   }


-supply_response:
-  /* Add the resp to the list used by tls_server_stapling_cb() */
+#ifdef EXIM_HAVE_INOTIFY
+if (  opt_set_and_noexpand(ob->tls_certificate)
+   && opt_unset_or_noexpand(ob->tls_privatekey))
   {
-  ocsp_resplist ** op = &cbinfo->u_ocsp.server.olist, * oentry;
-  while (oentry = *op)
-    op = &oentry->next;
-  *op = oentry = store_get(sizeof(ocsp_resplist), FALSE);
-  oentry->next = NULL;
-  oentry->resp = resp;
+  if (  !watch
+     || (  tls_set_watch(ob->tls_certificate, FALSE)
+    && tls_set_watch(ob->tls_privatekey, FALSE)
+     )  )
+    {
+    uschar * pkey = ob->tls_privatekey;
+
+    DEBUG(D_tls)
+      debug_printf("TLS: preloading client certs for transport '%s'\n",t->name);
+
+    if (  tls_add_certfile(ctx, &tpt_dummy_state, ob->tls_certificate,
+                    &dummy_errstr) == 0
+       && tls_add_pkeyfile(ctx, &tpt_dummy_state,
+                    pkey ? pkey : ob->tls_certificate,
+                    &dummy_errstr) == 0
+       )
+      ob->tls_preload.conn_certs = TRUE;
+    }
   }
-return;
+else
+  DEBUG(D_tls)
+    debug_printf("TLS: not preloading client certs, for transport '%s'\n", t->name);


-bad:
-  if (f.running_in_test_harness)
+
+if (  opt_set_and_noexpand(ob->tls_verify_certificates)
+   && opt_unset_or_noexpand(ob->tls_crl))
+  {
+  if (  !watch
+     ||    tls_set_watch(CUS X509_get_default_cert_file(), FALSE)
+        && tls_set_watch(ob->tls_verify_certificates, FALSE)
+    && tls_set_watch(ob->tls_crl, FALSE)
+     )
     {
-    extern char ** environ;
-    if (environ) for (uschar ** p = USS environ; *p; p++)
-      if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
-    {
-    DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n");
-    goto supply_response;
-    }
+    DEBUG(D_tls)
+      debug_printf("TLS: preloading CA bundle for transport '%s'\n", t->name);
+
+    if (setup_certs(ctx, ob->tls_verify_certificates,
+      ob->tls_crl, dummy_host, &dummy_errstr) == OK)
+      ob->tls_preload.cabundle = TRUE;
     }
-return;
+  }
+else
+  DEBUG(D_tls)
+      debug_printf("TLS: not preloading CA bundle, for transport '%s'\n", t->name);
+
+#endif /*EXIM_HAVE_INOTIFY*/
 }



+#ifdef EXIM_HAVE_INOTIFY
+/* Invalidate the creds cached, by dropping the current ones.
+Call when we notice one of the source files has changed. */
+ 
 static void
-ocsp_free_response_list(tls_ext_ctx_cb * cbinfo)
+tls_server_creds_invalidate(void)
 {
-for (ocsp_resplist * olist = cbinfo->u_ocsp.server.olist; olist;
-     olist = olist->next)
-  OCSP_RESPONSE_free(olist->resp);
-cbinfo->u_ocsp.server.olist = NULL;
+SSL_CTX_free(state_server.lib_state.lib_ctx);
+state_server.lib_state = null_tls_preload;
 }
-#endif    /*!DISABLE_OCSP*/
-



+static void
+tls_client_creds_invalidate(transport_instance * t)
+{
+smtp_transport_options_block * ob = t->options_block;
+SSL_CTX_free(ob->tls_preload.lib_ctx);
+ob->tls_preload = null_tls_preload;
+}
+#endif    /*EXIM_HAVE_INOTIFY*/


-/* Create and install a selfsigned certificate, for use in server mode */

-static int
-tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr)
+/* Extreme debug
+#ifndef DISABLE_OCSP
+void
+x509_store_dump_cert_s_names(X509_STORE * store)
{
-X509 * x509 = NULL;
-EVP_PKEY * pkey;
-RSA * rsa;
-X509_NAME * name;
-uschar * where;
+STACK_OF(X509_OBJECT) * roots= store->objs;
+static uschar name[256];

-where = US"allocating pkey";
-if (!(pkey = EVP_PKEY_new()))
-  goto err;
+for (int i= 0; i < sk_X509_OBJECT_num(roots); i++)
+  {
+  X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i);
+  if(tmp_obj->type == X509_LU_X509)
+    {
+    X509_NAME * sn = X509_get_subject_name(tmp_obj->data.x509);
+    if (X509_NAME_oneline(sn, CS name, sizeof(name)))
+      {
+      name[sizeof(name)-1] = '\0';
+      debug_printf(" %s\n", name);
+      }
+    }
+  }
+}
+#endif
+*/


-where = US"allocating cert";
-if (!(x509 = X509_new()))
- goto err;

-where = US"generating pkey";
-if (!(rsa = rsa_callback(NULL, 0, 2048)))
- goto err;
+#ifndef DISABLE_TLS_RESUME
+/* Manage the keysets used for encrypting the session tickets, on the server. */

-where = US"assigning pkey";
-if (!EVP_PKEY_assign_RSA(pkey, rsa))
-  goto err;
+typedef struct {            /* Session ticket encryption key */
+  uschar     name[16];


-X509_set_version(x509, 2);                /* N+1 - version 3 */
-ASN1_INTEGER_set(X509_get_serialNumber(x509), 1);
-X509_gmtime_adj(X509_get_notBefore(x509), 0);
-X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60);    /* 1 hour */
-X509_set_pubkey(x509, pkey);
+  const EVP_CIPHER *    aes_cipher;
+  uschar        aes_key[32];    /* size needed depends on cipher. aes_128 implies 128/8 = 16? */
+  const EVP_MD *    hmac_hash;
+  uschar        hmac_key[16];
+  time_t        renew;
+  time_t        expire;
+} exim_stek;


-name = X509_get_subject_name(x509);
-X509_NAME_add_entry_by_txt(name, "C",
-              MBSTRING_ASC, CUS "UK", -1, -1, 0);
-X509_NAME_add_entry_by_txt(name, "O",
-              MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0);
-X509_NAME_add_entry_by_txt(name, "CN",
-              MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0);
-X509_set_issuer_name(x509, name);
+static exim_stek exim_tk;    /* current key */
+static exim_stek exim_tk_old;    /* previous key */


-where = US"signing cert";
-if (!X509_sign(x509, pkey, EVP_md5()))
- goto err;
+static void
+tk_init(void)
+{
+time_t t = time(NULL);

-where = US"installing selfsign cert";
-if (!SSL_CTX_use_certificate(sctx, x509))
- goto err;
+if (exim_tk.name[0])
+ {
+ if (exim_tk.renew >= t) return;
+ exim_tk_old = exim_tk;
+ }

-where = US"installing selfsign key";
-if (!SSL_CTX_use_PrivateKey(sctx, pkey))
- goto err;
+if (f.running_in_test_harness) ssl_session_timeout = 6;

-return OK;
+DEBUG(D_tls) debug_printf("OpenSSL: %s STEK\n", exim_tk.name[0] ? "rotating" : "creating");
+if (RAND_bytes(exim_tk.aes_key, sizeof(exim_tk.aes_key)) <= 0) return;
+if (RAND_bytes(exim_tk.hmac_key, sizeof(exim_tk.hmac_key)) <= 0) return;
+if (RAND_bytes(exim_tk.name+1, sizeof(exim_tk.name)-1) <= 0) return;

-err:
- (void) tls_error(where, NULL, NULL, errstr);
- if (x509) X509_free(x509);
- if (pkey) EVP_PKEY_free(pkey);
- return DEFER;
+exim_tk.name[0] = 'E';
+exim_tk.aes_cipher = EVP_aes_256_cbc();
+exim_tk.hmac_hash = EVP_sha256();
+exim_tk.expire = t + ssl_session_timeout;
+exim_tk.renew = t + ssl_session_timeout/2;
}

-
-
-
-static int
-tls_add_certfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file,
-  uschar ** errstr)
+static exim_stek *
+tk_current(void)
 {
-DEBUG(D_tls) debug_printf("tls_certificate file '%s'\n", file);
-if (!SSL_CTX_use_certificate_chain_file(sctx, CS file))
-  return tls_error(string_sprintf(
-    "SSL_CTX_use_certificate_chain_file file=%s", file),
-      cbinfo->host, NULL, errstr);
-return 0;
+if (!exim_tk.name[0]) return NULL;
+return &exim_tk;
 }


-static int
-tls_add_pkeyfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file,
-  uschar ** errstr)
+static exim_stek *
+tk_find(const uschar * name)
 {
-DEBUG(D_tls) debug_printf("tls_privatekey file  '%s'\n", file);
-if (!SSL_CTX_use_PrivateKey_file(sctx, CS file, SSL_FILETYPE_PEM))
-  return tls_error(string_sprintf(
-    "SSL_CTX_use_PrivateKey_file file=%s", file), cbinfo->host, NULL, errstr);
-return 0;
+return memcmp(name, exim_tk.name, sizeof(exim_tk.name)) == 0 ? &exim_tk
+  : memcmp(name, exim_tk_old.name, sizeof(exim_tk_old.name)) == 0 ? &exim_tk_old
+  : NULL;
 }


-
-/*************************************************
-*        Expand key and cert file specs          *
-*************************************************/
-
-/* Called once during tls_init and possibly again during TLS setup, for a
-new context, if Server Name Indication was used and tls_sni was seen in
-the certificate string.
-
-Arguments:
-  sctx            the SSL_CTX* to update
-  cbinfo          various parts of session state
-  errstr      error string pointer
-
-Returns:          OK/DEFER/FAIL
-*/
-
+/* Callback for session tickets, on server */
 static int
-tls_expand_session_files(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo,
-  uschar ** errstr)
+ticket_key_callback(SSL * ssl, uschar key_name[16],
+  uschar * iv, EVP_CIPHER_CTX * c_ctx, HMAC_CTX * hctx, int enc)
 {
-uschar * expanded;
+tls_support * tlsp = state_server.tlsp;
+exim_stek * key;


-if (!cbinfo->certificate)
+if (enc)
   {
-  if (!cbinfo->is_server)        /* client */
-    return OK;
-                    /* server */
-  if (tls_install_selfsign(sctx, errstr) != OK)
-    return DEFER;
+  DEBUG(D_tls) debug_printf("ticket_key_callback: create new session\n");
+  tlsp->resumption |= RESUME_CLIENT_REQUESTED;
+
+  if (RAND_bytes(iv, EVP_MAX_IV_LENGTH) <= 0)
+    return -1; /* insufficient random */
+
+  if (!(key = tk_current()))    /* current key doesn't exist or isn't valid */
+     return 0;            /* key couldn't be created */
+  memcpy(key_name, key->name, 16);
+  DEBUG(D_tls) debug_printf("STEK expire " TIME_T_FMT "\n", key->expire - time(NULL));
+
+  /*XXX will want these dependent on the ssl session strength */
+  HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key),
+        key->hmac_hash, NULL);
+  EVP_EncryptInit_ex(c_ctx, key->aes_cipher, NULL, key->aes_key, iv);
+
+  DEBUG(D_tls) debug_printf("ticket created\n");
+  return 1;
   }
 else
   {
-  int err;
-
-  if ( !reexpand_tls_files_for_sni
-     && (  Ustrstr(cbinfo->certificate, US"tls_sni")
-    || Ustrstr(cbinfo->certificate, US"tls_in_sni")
-    || Ustrstr(cbinfo->certificate, US"tls_out_sni")
-     )  )
-    reexpand_tls_files_for_sni = TRUE;
+  time_t now = time(NULL);


-  if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr))
-    return DEFER;
+  DEBUG(D_tls) debug_printf("ticket_key_callback: retrieve session\n");
+  tlsp->resumption |= RESUME_CLIENT_SUGGESTED;


-  if (expanded)
-    if (cbinfo->is_server)
+  if (!(key = tk_find(key_name)) || key->expire < now)
+    {
+    DEBUG(D_tls)
       {
-      const uschar * file_list = expanded;
-      int sep = 0;
-      uschar * file;
-#ifndef DISABLE_OCSP
-      const uschar * olist = cbinfo->u_ocsp.server.file;
-      int osep = 0;
-      uschar * ofile;
-      BOOL fmt_pem = FALSE;
-
-      if (olist)
-    if (!expand_check(olist, US"tls_ocsp_file", USS &olist, errstr))
-      return DEFER;
-      if (olist && !*olist)
-    olist = NULL;
+      debug_printf("ticket not usable (%s)\n", key ? "expired" : "not found");
+      if (key) debug_printf("STEK expire " TIME_T_FMT "\n", key->expire - now);
+      }
+    return 0;
+    }


-      if (  cbinfo->u_ocsp.server.file_expanded && olist
-     && (Ustrcmp(olist, cbinfo->u_ocsp.server.file_expanded) == 0))
-    {
-    DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n");
-    olist = NULL;
-    }
-      else
-    {
-    ocsp_free_response_list(cbinfo);
-    cbinfo->u_ocsp.server.file_expanded = olist;
-    }
-#endif
+  HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key),
+        key->hmac_hash, NULL);
+  EVP_DecryptInit_ex(c_ctx, key->aes_cipher, NULL, key->aes_key, iv);


-      while (file = string_nextinlist(&file_list, &sep, NULL, 0))
-    {
-    if ((err = tls_add_certfile(sctx, cbinfo, file, errstr)))
-      return err;
+  DEBUG(D_tls) debug_printf("ticket usable, STEK expire " TIME_T_FMT "\n", key->expire - now);


-#ifndef DISABLE_OCSP
-    if (olist)
-      if ((ofile = string_nextinlist(&olist, &osep, NULL, 0)))
-        {
-        if (Ustrncmp(ofile, US"PEM ", 4) == 0)
-          {
-          fmt_pem = TRUE;
-          ofile += 4;
-          }
-        else if (Ustrncmp(ofile, US"DER ", 4) == 0)
-          {
-          fmt_pem = FALSE;
-          ofile += 4;
-          }
-        ocsp_load_response(sctx, cbinfo, ofile, fmt_pem);
-        }
-      else
-        DEBUG(D_tls) debug_printf("ran out of ocsp file list\n");
+  /* The ticket lifetime and renewal are the same as the STEK lifetime and
+  renewal, which is overenthusiastic.  A factor of, say, 3x longer STEK would
+  be better.  To do that we'd have to encode ticket lifetime in the name as
+  we don't yet see the restored session.  Could check posthandshake for TLS1.3
+  and trigger a new ticket then, but cannot do that for TLS1.2 */
+  return key->renew < now ? 2 : 1;
+  }
+}
 #endif
-    }
-      }
-    else    /* would there ever be a need for multiple client certs? */
-      if ((err = tls_add_certfile(sctx, cbinfo, expanded, errstr)))
-    return err;
-
-  if (  cbinfo->privatekey
-     && !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr))
-    return DEFER;


- /* If expansion was forced to fail, key_expanded will be NULL. If the result
- of the expansion is an empty string, ignore it also, and assume the private
- key is in the same file as the certificate. */

-  if (expanded && *expanded)
-    if (cbinfo->is_server)
-      {
-      const uschar * file_list = expanded;
-      int sep = 0;
-      uschar * file;


-      while (file = string_nextinlist(&file_list, &sep, NULL, 0))
-    if ((err = tls_add_pkeyfile(sctx, cbinfo, file, errstr)))
-      return err;
-      }
-    else    /* would there ever be a need for multiple client certs? */
-      if ((err = tls_add_pkeyfile(sctx, cbinfo, expanded, errstr)))
-    return err;
-  }
+static void
+setup_cert_verify(SSL_CTX * ctx, BOOL optional,
+    int (*cert_vfy_cb)(int, X509_STORE_CTX *))
+{
+/* If verification is optional, don't fail if no certificate */


-return OK;
+SSL_CTX_set_verify(ctx,
+    SSL_VERIFY_PEER | (optional ? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT),
+    cert_vfy_cb);
 }



-
-
 /*************************************************
 *            Callback to handle SNI              *
 *************************************************/
@@ -1682,7 +2229,7 @@ static int
 tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg)
 {
 const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
-tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
+exim_openssl_state_st *state = (exim_openssl_state_st *) arg;
 int rc;
 int old_pool = store_pool;
 uschar * dummy_errstr;
@@ -1705,51 +2252,54 @@ if (!reexpand_tls_files_for_sni)
 not confident that memcpy wouldn't break some internal reference counting.
 Especially since there's a references struct member, which would be off. */


-#ifdef EXIM_HAVE_OPENSSL_TLS_METHOD
-if (!(server_sni = SSL_CTX_new(TLS_server_method())))
-#else
-if (!(server_sni = SSL_CTX_new(SSLv23_server_method())))
-#endif
- {
- ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring));
- DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring);
+if (lib_ctx_new(&server_sni, NULL, &dummy_errstr) != OK)
goto bad;
- }

/* Not sure how many of these are actually needed, since SSL object
already exists. Might even need this selfsame callback, for reneg? */

-SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx));
-SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx));
-SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx));
-SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx));
-SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
-SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo);
+ {
+ SSL_CTX * ctx = state_server.lib_state.lib_ctx;
+ SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(ctx));
+ SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(ctx));
+ SSL_CTX_set_options(server_sni, SSL_CTX_get_options(ctx));
+ SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(ctx));
+ SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
+ SSL_CTX_set_tlsext_servername_arg(server_sni, state);
+ }

-if (  !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr)
+if (  !init_dh(server_sni, state->dhparam, NULL, &dummy_errstr)
    || !init_ecdh(server_sni, NULL, &dummy_errstr)
    )
   goto bad;


-if ( cbinfo->server_cipher_list
- && !SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list))
+if ( state->server_cipher_list
+ && !SSL_CTX_set_cipher_list(server_sni, CS state->server_cipher_list))
goto bad;

#ifndef DISABLE_OCSP
-if (cbinfo->u_ocsp.server.file)
+if (state->u_ocsp.server.file)
{
SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb);
- SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo);
+ SSL_CTX_set_tlsext_status_arg(server_sni, state);
}
#endif

-if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE,
-              verify_callback_server, &dummy_errstr)) != OK)
-  goto bad;
+  {
+  uschar * expcerts;
+  if (  !expand_check(tls_verify_certificates, US"tls_verify_certificates",
+          &expcerts, &dummy_errstr)
+     || (rc = setup_certs(server_sni, expcerts, tls_crl, NULL,
+            &dummy_errstr)) != OK)
+    goto bad;
+
+  if (expcerts && *expcerts)
+    setup_cert_verify(server_sni, FALSE, verify_callback_server);
+  }


/* do this after setup_certs, because this can require the certs for verifying
OCSP information. */
-if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK)
+if ((rc = tls_expand_session_files(server_sni, state, &dummy_errstr)) != OK)
goto bad;

 DEBUG(D_tls) debug_printf("Switching SSL context.\n");
@@ -1780,8 +2330,8 @@ project.
 static int
 tls_server_stapling_cb(SSL *s, void *arg)
 {
-const tls_ext_ctx_cb * cbinfo = (tls_ext_ctx_cb *) arg;
-ocsp_resplist * olist = cbinfo->u_ocsp.server.olist;
+const exim_openssl_state_st * state = arg;
+ocsp_resplist * olist = state->u_ocsp.server.olist;
 uschar * response_der;    /*XXX blob */
 int response_der_len;


@@ -1855,7 +2405,8 @@ response_der_len = i2d_OCSP_RESPONSE(olist->resp, &response_der);
if (response_der_len <= 0)
return SSL_TLSEXT_ERR_NOACK;

-SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len);
+SSL_set_tlsext_status_ocsp_resp(state_server.lib_state.lib_ssl,
+                response_der, response_der_len);
 tls_in.ocsp = OCSP_VFIED;
 return SSL_TLSEXT_ERR_OK;
 }
@@ -1872,7 +2423,7 @@ BIO_puts(bp, "\n");
 static int
 tls_client_stapling_cb(SSL *s, void *arg)
 {
-tls_ext_ctx_cb * cbinfo = arg;
+exim_openssl_state_st * cbinfo = arg;
 const unsigned char * p;
 int len;
 OCSP_RESPONSE * rsp;
@@ -2032,95 +2583,64 @@ return i;
 /*************************************************
 *            Initialize for TLS                  *
 *************************************************/
-
-static void
-tls_openssl_init(void)
-{
-#ifdef EXIM_NEED_OPENSSL_INIT
-SSL_load_error_strings();          /* basic set up */
-OpenSSL_add_ssl_algorithms();
-#endif
-
-#if defined(EXIM_HAVE_SHA256) && !defined(OPENSSL_AUTO_SHA256)
-/* SHA256 is becoming ever more popular. This makes sure it gets added to the
-list of available digests. */
-EVP_add_digest(EVP_sha256());
-#endif
-}
-
-
-
 /* Called from both server and client code, to do preliminary initialization
 of the library.  We allocate and return a context structure.


 Arguments:
-  ctxp            returned SSL context
   host            connected host, if client; NULL if server
-  dhparam         DH parameter file
-  certificate     certificate file
-  privatekey      private key
+  ob          transport options block, if client; NULL if server
   ocsp_file       file of stapling info (server); flag for require ocsp (client)
   addr            address if client; NULL if server (for some randomness)
-  cbp             place to put allocated callback context
+  caller_state    place to put pointer to allocated state-struct
   errstr      error string pointer


 Returns:          OK/DEFER/FAIL
 */


static int
-tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate,
- uschar *privatekey,
+tls_init(host_item * host, smtp_transport_options_block * ob,
#ifndef DISABLE_OCSP
uschar *ocsp_file,
#endif
- address_item *addr, tls_ext_ctx_cb ** cbp,
+ address_item *addr, exim_openssl_state_st ** caller_state,
tls_support * tlsp,
uschar ** errstr)
{
SSL_CTX * ctx;
-long init_options;
+exim_openssl_state_st * state;
int rc;
-tls_ext_ctx_cb * cbinfo;

-cbinfo = store_malloc(sizeof(tls_ext_ctx_cb));
-cbinfo->tlsp = tlsp;
-cbinfo->certificate = certificate;
-cbinfo->privatekey = privatekey;
-cbinfo->is_server = host==NULL;
-#ifndef DISABLE_OCSP
-cbinfo->verify_stack = NULL;
-if (!host)
+if (host)            /* client */
   {
-  cbinfo->u_ocsp.server.file = ocsp_file;
-  cbinfo->u_ocsp.server.file_expanded = NULL;
-  cbinfo->u_ocsp.server.olist = NULL;
+  state = store_malloc(sizeof(exim_openssl_state_st));
+  memset(state, 0, sizeof(*state));
+  state->certificate = ob->tls_certificate;
+  state->privatekey =  ob->tls_privatekey;
+  state->is_server = FALSE;
+  state->dhparam = NULL;
+  state->lib_state = ob->tls_preload;
+  }
+else                /* server */
+  {
+  state = &state_server;
+  state->certificate = tls_certificate;
+  state->privatekey =  tls_privatekey;
+  state->is_server = TRUE;
+  state->dhparam = tls_dhparam;
+  state->lib_state = state_server.lib_state;
   }
-else
-  cbinfo->u_ocsp.client.verify_store = NULL;
-#endif
-cbinfo->dhparam = dhparam;
-cbinfo->server_cipher_list = NULL;
-cbinfo->host = host;
-#ifndef DISABLE_EVENT
-cbinfo->event_action = NULL;
-#endif


-tls_openssl_init();
+state->tlsp = tlsp;
+state->host = host;

-/* Create a context.
-The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant
-negotiation in the different methods; as far as I can tell, the only
-*_{server,client}_method which allows negotiation is SSLv23, which exists even
-when OpenSSL is built without SSLv2 support.
-By disabling with openssl_options, we can let admins re-enable with the
-existing knob. */
+if (!state->lib_state.pri_string)
+ state->server_cipher_list = NULL;

-#ifdef EXIM_HAVE_OPENSSL_TLS_METHOD
-if (!(ctx = SSL_CTX_new(host ? TLS_client_method() : TLS_server_method())))
-#else
-if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method())))
+#ifndef DISABLE_EVENT
+state->event_action = NULL;
#endif
- return tls_error(US"SSL_CTX_new", host, NULL, errstr);
+
+tls_openssl_init();

/* It turns out that we need to seed the random number generator this early in
order to get the full complement of ciphers to work. It took me roughly a day
@@ -2128,40 +2648,14 @@ of work to discover this by experiment.

 On systems that have /dev/urandom, SSL may automatically seed itself from
 there. Otherwise, we have to make something up as best we can. Double check
-afterwards. */
-
-if (!RAND_status())
-  {
-  randstuff r;
-  gettimeofday(&r.tv, NULL);
-  r.p = getpid();
-
-  RAND_seed(US (&r), sizeof(r));
-  RAND_seed(US big_buffer, big_buffer_size);
-  if (addr != NULL) RAND_seed(US addr, sizeof(addr));
-
-  if (!RAND_status())
-    return tls_error(US"RAND_status", host,
-      US"unable to seed random number generator", errstr);
-  }
-
-/* Set up the information callback, which outputs if debugging is at a suitable
-level. */
+afterwards.


-DEBUG(D_tls)
- {
- SSL_CTX_set_info_callback(ctx, (void (*)())info_callback);
-#if defined(EXIM_HAVE_OPESSL_TRACE) && !defined(OPENSSL_NO_SSL_TRACE)
- /* this needs a debug build of OpenSSL */
- SSL_CTX_set_msg_callback(ctx, (void (*)())SSL_trace);
-#endif
-#ifdef OPENSSL_HAVE_KEYLOG_CB
- SSL_CTX_set_keylog_callback(ctx, (void (*)())keylog_callback);
-#endif
- }
+Although we likely called this before, at daemon startup, this is a chance
+to mix in further variable info (time, pid) if needed. */

-/* Automatically re-try reads/writes after renegotiation. */
-(void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
+if (!lib_rand_init(addr))
+  return tls_error(US"RAND_status", host,
+    US"unable to seed random number generator", errstr);


/* Apply administrator-supplied work-arounds.
Historically we applied just one requested option,
@@ -2172,8 +2666,24 @@ grandfathered in the first one as the default value for "openssl_options".
No OpenSSL version number checks: the options we accept depend upon the
availability of the option value macros from OpenSSL. */

-if (!tls_openssl_options_parse(openssl_options, &init_options))
-  return tls_error(US"openssl_options parsing failed", host, NULL, errstr);
+if (!init_options)
+  if (!tls_openssl_options_parse(openssl_options, &init_options))
+    return tls_error(US"openssl_options parsing failed", host, NULL, errstr);
+
+/* Create a context.
+The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant
+negotiation in the different methods; as far as I can tell, the only
+*_{server,client}_method which allows negotiation is SSLv23, which exists even
+when OpenSSL is built without SSLv2 support.
+By disabling with openssl_options, we can let admins re-enable with the
+existing knob. */
+
+if (!(ctx = state->lib_state.lib_ctx))
+  {
+  if ((rc = lib_ctx_new(&ctx, host, errstr)) != OK)
+    return rc;
+  state->lib_state.lib_ctx = ctx;
+  }


#ifndef DISABLE_TLS_RESUME
tlsp->resumption = RESUME_SUPPORTED;
@@ -2212,21 +2722,41 @@ will never be used because we use a new context every time. */
/* Initialize with DH parameters if supplied */
/* Initialize ECDH temp key parameter selection */

-if ( !init_dh(ctx, dhparam, host, errstr)
- || !init_ecdh(ctx, host, errstr)
- )
- return DEFER;
+if (state->lib_state.dh)
+ { DEBUG(D_tls) debug_printf("TLS: DH params were preloaded\n"); }
+else
+ if (!init_dh(ctx, state->dhparam, host, errstr)) return DEFER;
+
+if (state->lib_state.ecdh)
+ { DEBUG(D_tls) debug_printf("TLS: ECDH curve was preloaded\n"); }
+else
+ if (!init_ecdh(ctx, host, errstr)) return DEFER;

/* Set up certificate and key (and perhaps OCSP info) */

-if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK)
-  return rc;
+if (state->lib_state.conn_certs)
+  {
+  DEBUG(D_tls)
+    debug_printf("TLS: %s certs were preloaded\n", host ? "client":"server");
+  }
+else
+  {
+#ifndef DISABLE_OCSP
+  if (!host)
+    {
+    state->u_ocsp.server.file = ocsp_file;
+    state->u_ocsp.server.file_expanded = NULL;
+    state->u_ocsp.server.olist = NULL;
+    }
+#endif
+  if ((rc = tls_expand_session_files(ctx, state, errstr)) != OK) return rc;
+  }


/* If we need to handle SNI or OCSP, do so */

 #ifdef EXIM_HAVE_OPENSSL_TLSEXT
 # ifndef DISABLE_OCSP
-  if (!(cbinfo->verify_stack = sk_X509_new_null()))
+  if (!(state->verify_stack = sk_X509_new_null()))
     {
     DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n");
     return FAIL;
@@ -2240,33 +2770,33 @@ if (!host)        /* server */
   the option exists, not what the current expansion might be, as SNI might
   change the certificate and OCSP file in use between now and the time the
   callback is invoked. */
-  if (cbinfo->u_ocsp.server.file)
+  if (state->u_ocsp.server.file)
     {
     SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb);
-    SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
+    SSL_CTX_set_tlsext_status_arg(ctx, state);
     }
 # endif
   /* We always do this, so that $tls_sni is available even if not used in
   tls_certificate */
   SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb);
-  SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo);
+  SSL_CTX_set_tlsext_servername_arg(ctx, state);
   }
 # ifndef DISABLE_OCSP
 else            /* client */
   if(ocsp_file)        /* wanting stapling */
     {
-    if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new()))
+    if (!(state->u_ocsp.client.verify_store = X509_STORE_new()))
       {
       DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n");
       return FAIL;
       }
     SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb);
-    SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
+    SSL_CTX_set_tlsext_status_arg(ctx, state);
     }
 # endif
 #endif


-cbinfo->verify_cert_hostnames = NULL;
+state->verify_cert_hostnames = NULL;

#ifdef EXIM_HAVE_EPHEM_RSA_KEX
/* Set up the RSA callback */
@@ -2279,8 +2809,7 @@ The period appears to be also used for (server-generated) session tickets */
SSL_CTX_set_timeout(ctx, ssl_session_timeout);
DEBUG(D_tls) debug_printf("Initialized TLS\n");

-*cbp = cbinfo;
-*ctxp = ctx;
+*caller_state = state;

return OK;
}
@@ -2430,20 +2959,17 @@ repeated after a Server Name Indication.

 Arguments:
   sctx          SSL_CTX* to initialise
-  certs         certs file or NULL
+  certs         certs file, expanded
   crl           CRL file or NULL
   host          NULL in a server; the remote host in a client
-  optional      TRUE if called from a server for a host in tls_try_verify_hosts;
-                otherwise passed as FALSE
-  cert_vfy_cb    Callback function for certificate verification
   errstr    error string pointer


 Returns:        OK/DEFER/FAIL
 */


 static int
-setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
-    int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr)
+setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host,
+    uschar ** errstr)
 {
 uschar *expcerts, *expcrl;


@@ -2459,7 +2985,7 @@ if (expcerts && *expcerts)
   if (!SSL_CTX_set_default_verify_paths(sctx))
     return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr);


-  if (Ustrcmp(expcerts, "system") != 0)
+  if (Ustrcmp(expcerts, "system") != 0 && Ustrncmp(expcerts, "system,", 7) != 0)
     {
     struct stat statbuf;


@@ -2487,8 +3013,8 @@ This is inconsistent with the need to verify the OCSP proof of the server cert.

     if (  !host
        && statbuf.st_size > 0
-       && server_static_cbinfo->u_ocsp.server.file
-       && !chain_from_pem_file(file, server_static_cbinfo->verify_stack)
+       && state_server.u_ocsp.server.file
+       && !chain_from_pem_file(file, state_server.verify_stack)
        )
       {
       log_write(0, LOG_MAIN|LOG_PANIC,
@@ -2505,7 +3031,8 @@ This is inconsistent with the need to verify the OCSP proof of the server cert.


       if (  (!file || statbuf.st_size > 0)
          && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir))
-    return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr);
+      return tls_error(US"SSL_CTX_load_verify_locations",
+                host, NULL, errstr);


       /* On the server load the list of CAs for which we will accept certs, for
       sending to the client.  This is only for the one-file
@@ -2520,11 +3047,15 @@ This is inconsistent with the need to verify the OCSP proof of the server cert.
       if (file)
     {
     STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file);
+    int i = sk_X509_NAME_num(names);


     if (!host) SSL_CTX_set_client_CA_list(sctx, names);
-    DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n",
-                    sk_X509_NAME_num(names));
+    DEBUG(D_tls) debug_printf("Added %d additional certificate authorit%s\n",
+                    i, i>1 ? "ies":"y");
     }
+      else
+    DEBUG(D_tls)
+      debug_printf("Added dir for additional certificate authorities\n");
       }
     }


@@ -2580,12 +3111,6 @@ This is inconsistent with the need to verify the OCSP proof of the server cert.
     }


 #endif  /* OPENSSL_VERSION_NUMBER > 0x00907000L */
-
-  /* If verification is optional, don't fail if no certificate */
-
-  SSL_CTX_set_verify(sctx,
-    SSL_VERIFY_PEER | (optional ? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT),
-    cert_vfy_cb);
   }


 return OK;
@@ -2596,13 +3121,11 @@ return OK;
 /*************************************************
 *       Start a TLS session in a server          *
 *************************************************/
-
 /* This is called when Exim is running as a server, after having received
 the STARTTLS command. It must respond to that command, and then negotiate
 a TLS session.


 Arguments:
-  require_ciphers   allowed ciphers
   errstr        pointer to error message


 Returns:            OK on success
@@ -2612,11 +3135,13 @@ Returns:            OK on success
 */


int
-tls_server_start(const uschar * require_ciphers, uschar ** errstr)
+tls_server_start(uschar ** errstr)
{
int rc;
uschar * expciphers;
-tls_ext_ctx_cb * cbinfo;
+exim_openssl_state_st * dummy_statep;
+SSL_CTX * ctx;
+SSL * ssl;
static uschar peerdn[256];

/* Check for previous activation */
@@ -2631,16 +3156,13 @@ if (tls_in.active.sock >= 0)
/* Initialize the SSL library. If it fails, it will already have logged
the error. */

-rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey,
+rc = tls_init(NULL, NULL,
 #ifndef DISABLE_OCSP
     tls_ocsp_file,
 #endif
-    NULL, &server_static_cbinfo, &tls_in, errstr);
+    NULL, &dummy_statep, &tls_in, errstr);
 if (rc != OK) return rc;
-cbinfo = server_static_cbinfo;
-
-if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr))
-  return FAIL;
+ctx = state_server.lib_state.lib_ctx;


/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
were historically separated by underscores. So that I can use either form in my
@@ -2651,13 +3173,16 @@ for TLS 1.3 . Since we do not call it at present we get the default list:
TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256
*/

-if (expciphers)
+if (state_server.lib_state.pri_string)
+  { DEBUG(D_tls) debug_printf("TLS: cipher list was preloaded\n"); }
+else 
   {
-  for (uschar * s = expciphers; *s; s++ ) if (*s == '_') *s = '-';
-  DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
-  if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers))
-    return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr);
-  cbinfo->server_cipher_list = expciphers;
+  if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, errstr))
+    return FAIL;
+
+  if (  expciphers
+     && (rc = server_load_ciphers(ctx, &state_server, expciphers, errstr)) != OK)
+    return rc;
   }


/* If this is a host for which certificate verification is mandatory or
@@ -2670,37 +3195,48 @@ tls_in.dane_verified = FALSE;
server_verify_callback_called = FALSE;

 if (verify_check_host(&tls_verify_hosts) == OK)
-  {
-  rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
-            FALSE, verify_callback_server, errstr);
-  if (rc != OK) return rc;
   server_verify_optional = FALSE;
-  }
 else if (verify_check_host(&tls_try_verify_hosts) == OK)
-  {
-  rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
-            TRUE, verify_callback_server, errstr);
-  if (rc != OK) return rc;
   server_verify_optional = TRUE;
+else
+  goto skip_certs;
+
+  {
+  uschar * expcerts;
+  if (!expand_check(tls_verify_certificates, US"tls_verify_certificates",
+            &expcerts, errstr))
+    return DEFER;
+  DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts);
+
+  if (state_server.lib_state.cabundle)
+    { DEBUG(D_tls) debug_printf("TLS: CA bundle for server was preloaded\n"); }
+  else
+    if ((rc = setup_certs(ctx, expcerts, tls_crl, NULL, errstr)) != OK)
+      return rc;
+
+  if (expcerts && *expcerts)
+    setup_cert_verify(ctx, server_verify_optional, verify_callback_server);
   }
+skip_certs: ;


 #ifndef DISABLE_TLS_RESUME
-SSL_CTX_set_tlsext_ticket_key_cb(server_ctx, ticket_key_callback);
+SSL_CTX_set_tlsext_ticket_key_cb(ctx, ticket_key_callback);
 /* despite working, appears to always return failure, so ignoring */
 #endif
 #ifdef OPENSSL_HAVE_NUM_TICKETS
 # ifndef DISABLE_TLS_RESUME
-SSL_CTX_set_num_tickets(server_ctx, tls_in.host_resumable ? 1 : 0);
+SSL_CTX_set_num_tickets(ctx, tls_in.host_resumable ? 1 : 0);
 # else
-SSL_CTX_set_num_tickets(server_ctx, 0);    /* send no TLS1.3 stateful-tickets */
+SSL_CTX_set_num_tickets(ctx, 0);    /* send no TLS1.3 stateful-tickets */
 # endif
 #endif



/* Prepare for new connection */

-if (!(server_ssl = SSL_new(server_ctx)))
+if (!(ssl = SSL_new(ctx)))
return tls_error(US"SSL_new", NULL, NULL, errstr);
+state_server.lib_state.lib_ssl = ssl;

/* Warning: we used to SSL_clear(ssl) here, it was removed.
*
@@ -2721,7 +3257,7 @@ make them disconnect. We need to have an explicit fflush() here, to force out
the response. Other smtp_printf() calls do not need it, because in non-TLS
mode, the fflush() happens when smtp_getc() is called. */

-SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx));
+SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx));
if (!tls_in.on_connect)
{
smtp_printf("220 TLS go ahead\r\n", FALSE);
@@ -2731,21 +3267,21 @@ if (!tls_in.on_connect)
/* Now negotiate the TLS session. We put our own timer on it, since it seems
that the OpenSSL library doesn't. */

-SSL_set_wfd(server_ssl, fileno(smtp_out));
-SSL_set_rfd(server_ssl, fileno(smtp_in));
-SSL_set_accept_state(server_ssl);
+SSL_set_wfd(ssl, fileno(smtp_out));
+SSL_set_rfd(ssl, fileno(smtp_in));
+SSL_set_accept_state(ssl);

DEBUG(D_tls) debug_printf("Calling SSL_accept\n");

ERR_clear_error();
sigalrm_seen = FALSE;
if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
-rc = SSL_accept(server_ssl);
+rc = SSL_accept(ssl);
ALARM_CLR(0);

 if (rc <= 0)
   {
-  int error = SSL_get_error(server_ssl, rc);
+  int error = SSL_get_error(ssl, rc);
   switch(error)
     {
     case SSL_ERROR_NONE:
@@ -2755,8 +3291,8 @@ if (rc <= 0)
       DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
       (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr);


-      if (SSL_get_shutdown(server_ssl) == SSL_RECEIVED_SHUTDOWN)
-        SSL_shutdown(server_ssl);
+      if (SSL_get_shutdown(ssl) == SSL_RECEIVED_SHUTDOWN)
+        SSL_shutdown(ssl);


       tls_close(NULL, TLS_NO_SHUTDOWN);
       return FAIL;
@@ -2771,7 +3307,7 @@ if (rc <= 0)
          || r == SSL_R_VERSION_TOO_LOW
 #endif
          || r == SSL_R_UNKNOWN_PROTOCOL || r == SSL_R_UNSUPPORTED_PROTOCOL)
-    s = string_sprintf("%s (%s)", s, SSL_get_version(server_ssl));
+    s = string_sprintf("%s (%s)", s, SSL_get_version(ssl));
       (void) tls_error(s, NULL, sigalrm_seen ? US"timed out" : NULL, errstr);
       return FAIL;
       }
@@ -2800,7 +3336,7 @@ ERR_clear_error();    /* Even success can leave errors in the stack. Seen with
             anon-authentication ciphersuite negotiated. */


#ifndef DISABLE_TLS_RESUME
-if (SSL_session_reused(server_ssl))
+if (SSL_session_reused(ssl))
{
tls_in.resumption |= RESUME_USED;
DEBUG(D_tls) debug_printf("Session reused\n");
@@ -2811,31 +3347,31 @@ if (SSL_session_reused(server_ssl))
adjust the input functions to read via TLS, and initialize things. */

#ifdef SSL_get_extms_support
-tls_in.ext_master_secret = SSL_get_extms_support(server_ssl) == 1;
+tls_in.ext_master_secret = SSL_get_extms_support(ssl) == 1;
#endif
-peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn));
+peer_cert(ssl, &tls_in, peerdn, sizeof(peerdn));

-tls_in.ver = tlsver_name(server_ssl);
-tls_in.cipher = construct_cipher_name(server_ssl, tls_in.ver, &tls_in.bits);
-tls_in.cipher_stdname = cipher_stdname_ssl(server_ssl);
+tls_in.ver = tlsver_name(ssl);
+tls_in.cipher = construct_cipher_name(ssl, tls_in.ver, &tls_in.bits);
+tls_in.cipher_stdname = cipher_stdname_ssl(ssl);

 DEBUG(D_tls)
   {
   uschar buf[2048];
-  if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)))
+  if (SSL_get_shared_ciphers(ssl, CS buf, sizeof(buf)))
     debug_printf("Shared ciphers: %s\n", buf);


#ifdef EXIM_HAVE_OPENSSL_KEYLOG
{
BIO * bp = BIO_new_fp(debug_file, BIO_NOCLOSE);
- SSL_SESSION_print_keylog(bp, SSL_get_session(server_ssl));
+ SSL_SESSION_print_keylog(bp, SSL_get_session(ssl));
BIO_free(bp);
}
#endif

 #ifdef EXIM_HAVE_SESSION_TICKET
   {
-  SSL_SESSION * ss = SSL_get_session(server_ssl);
+  SSL_SESSION * ss = SSL_get_session(ssl);
   if (SSL_SESSION_has_ticket(ss))    /* 1.1.0 */
     debug_printf("The session has a ticket, life %lu seconds\n",
       SSL_SESSION_get_ticket_lifetime_hint(ss));
@@ -2845,7 +3381,7 @@ DEBUG(D_tls)


/* Record the certificate we presented */
{
- X509 * crt = SSL_get_certificate(server_ssl);
+ X509 * crt = SSL_get_certificate(ssl);
tls_in.ourcert = crt ? X509_dup(crt) : NULL;
}

@@ -2853,10 +3389,10 @@ DEBUG(D_tls)
See description in https://paquier.xyz/postgresql-2/channel-binding-openssl/ */
{
uschar c, * s;
- size_t len = SSL_get_peer_finished(server_ssl, &c, 0);
+ size_t len = SSL_get_peer_finished(ssl, &c, 0);
int old_pool = store_pool;

-  SSL_get_peer_finished(server_ssl, s = store_get((int)len, FALSE), len);
+  SSL_get_peer_finished(ssl, s = store_get((int)len, FALSE), len);
   store_pool = POOL_PERM;
     tls_in.channelbinding = b64encode_taint(CUS s, (int)len, FALSE);
   store_pool = old_pool;
@@ -2890,7 +3426,7 @@ return OK;


 static int
 tls_client_basic_ctx_init(SSL_CTX * ctx,
-    host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo,
+    host_item * host, smtp_transport_options_block * ob, exim_openssl_state_st * state,
     uschar ** errstr)
 {
 int rc;
@@ -2914,21 +3450,33 @@ else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK)
 else
   return OK;


-if ((rc = setup_certs(ctx, ob->tls_verify_certificates,
-      ob->tls_crl, host, client_verify_optional, verify_callback_client,
-      errstr)) != OK)
-  return rc;
+  {
+  uschar * expcerts;
+  if (!expand_check(ob->tls_verify_certificates, US"tls_verify_certificates",
+            &expcerts, errstr))
+    return DEFER;
+  DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts);
+
+  if (state->lib_state.cabundle)
+    { DEBUG(D_tls) debug_printf("TLS: CA bundle was preloaded\n"); }
+  else
+    if ((rc = setup_certs(ctx, expcerts, ob->tls_crl, host, errstr)) != OK)
+      return rc;
+
+  if (expcerts && *expcerts)
+    setup_cert_verify(ctx, client_verify_optional, verify_callback_client);
+  }


 if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK)
   {
-  cbinfo->verify_cert_hostnames =
+  state->verify_cert_hostnames =
 #ifdef SUPPORT_I18N
     string_domain_utf8_to_alabel(host->certname, NULL);
 #else
     host->certname;
 #endif
   DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n",
-            cbinfo->verify_cert_hostnames);
+            state->verify_cert_hostnames);
   }
 return OK;
 }
@@ -3063,7 +3611,7 @@ if (tlsp->host_resumable)
 static int
 tls_save_session_cb(SSL * ssl, SSL_SESSION * ss)
 {
-tls_ext_ctx_cb * cbinfo = SSL_get_ex_data(ssl, tls_exdata_idx);
+exim_openssl_state_st * cbinfo = SSL_get_ex_data(ssl, tls_exdata_idx);
 tls_support * tlsp;


DEBUG(D_tls) debug_printf("tls_save_session_cb\n");
@@ -3129,12 +3677,12 @@ if (tlsp->host_resumable)
SSL_clear_options(ssl, SSL_OP_NO_TICKET);

   tls_exdata_idx = SSL_get_ex_new_index(0, 0, 0, 0, 0);
-  if (!SSL_set_ex_data(ssl, tls_exdata_idx, client_static_cbinfo))
+  if (!SSL_set_ex_data(ssl, tls_exdata_idx, client_static_state))
     {
     tls_error(US"set ex_data", host, NULL, errstr);
     return FALSE;
     }
-  debug_printf("tls_exdata_idx %d cbinfo %p\n", tls_exdata_idx, client_static_cbinfo);
+  debug_printf("tls_exdata_idx %d cbinfo %p\n", tls_exdata_idx, client_static_state);
   }


tlsp->resumption = RESUME_SUPPORTED;
@@ -3231,14 +3779,15 @@ tlsp->tlsa_usage = 0;
}
#endif

-rc = tls_init(&exim_client_ctx->ctx, host, NULL,
-    ob->tls_certificate, ob->tls_privatekey,
+rc = tls_init(host, ob,
 #ifndef DISABLE_OCSP
     (void *)(long)request_ocsp,
 #endif
-    cookie, &client_static_cbinfo, tlsp, errstr);
+    cookie, &client_static_state, tlsp, errstr);
 if (rc != OK) return FALSE;


+exim_client_ctx->ctx = client_static_state->lib_state.lib_ctx;
+
tlsp->certificate_verified = FALSE;
client_verify_callback_called = FALSE;

@@ -3299,9 +3848,9 @@ else

#endif

-  if (tls_client_basic_ctx_init(exim_client_ctx->ctx, host, ob,
-    client_static_cbinfo, errstr) != OK)
-    return FALSE;
+if (tls_client_basic_ctx_init(exim_client_ctx->ctx, host, ob,
+      client_static_state, errstr) != OK)
+  return FALSE;


#ifndef DISABLE_TLS_RESUME
tls_client_ctx_resume_prehandshake(exim_client_ctx, tlsp, ob, host);
@@ -3369,7 +3918,7 @@ if (request_ocsp)
if (request_ocsp)
{
SSL_set_tlsext_status_type(exim_client_ctx->ssl, TLSEXT_STATUSTYPE_ocsp);
- client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp;
+ client_static_state->u_ocsp.client.verify_required = require_ocsp;
tlsp->ocsp = OCSP_NOT_RESP;
}
#endif
@@ -3381,7 +3930,7 @@ if (!tls_client_ssl_resume_prehandshake(exim_client_ctx->ssl, tlsp, host,
#endif

#ifndef DISABLE_EVENT
-client_static_cbinfo->event_action = tb ? tb->event_action : NULL;
+client_static_state->event_action = tb ? tb->event_action : NULL;
#endif

/* There doesn't seem to be a built-in timeout on connection. */
@@ -3461,17 +4010,18 @@ return TRUE;
static BOOL
tls_refill(unsigned lim)
{
+SSL * ssl = state_server.lib_state.lib_ssl;
int error;
int inbytes;

-DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl,
+DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl,
ssl_xfer_buffer, ssl_xfer_buffer_size);

 ERR_clear_error();
 if (smtp_receive_timeout > 0) ALARM(smtp_receive_timeout);
-inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer,
+inbytes = SSL_read(ssl, CS ssl_xfer_buffer,
           MIN(ssl_xfer_buffer_size, lim));
-error = SSL_get_error(server_ssl, inbytes);
+error = SSL_get_error(ssl, inbytes);
 if (smtp_receive_timeout > 0) ALARM_CLR(0);


 if (had_command_timeout)        /* set by signal handler */
@@ -3495,8 +4045,8 @@ switch(error)
   case SSL_ERROR_ZERO_RETURN:
     DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");


-    if (SSL_get_shutdown(server_ssl) == SSL_RECEIVED_SHUTDOWN)
-      SSL_shutdown(server_ssl);
+    if (SSL_get_shutdown(ssl) == SSL_RECEIVED_SHUTDOWN)
+      SSL_shutdown(ssl);


     tls_close(NULL, TLS_NO_SHUTDOWN);
     return FALSE;
@@ -3587,7 +4137,8 @@ if (n > 0)
 BOOL
 tls_could_read(void)
 {
-return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(server_ssl) > 0;
+return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm
+      || SSL_pending(state_server.lib_state.lib_ssl) > 0;
 }



@@ -3610,7 +4161,8 @@ Only used by the client-side TLS.
 int
 tls_read(void * ct_ctx, uschar *buff, size_t len)
 {
-SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl;
+SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl
+          : state_server.lib_state.lib_ssl;
 int inbytes;
 int error;


@@ -3660,7 +4212,8 @@ tls_write(void * ct_ctx, const uschar * buff, size_t len, BOOL more)
 size_t olen = len;
 int outbytes, error;
 SSL * ssl = ct_ctx
-  ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl;
+  ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl
+  : state_server.lib_state.lib_ssl;
 static gstring * server_corked = NULL;
 gstring ** corkedp = ct_ctx
   ? &((exim_openssl_client_tls_ctx *)ct_ctx)->corked : &server_corked;
@@ -3772,8 +4325,7 @@ void
 tls_close(void * ct_ctx, int shutdown)
 {
 exim_openssl_client_tls_ctx * o_ctx = ct_ctx;
-SSL_CTX **ctxp = o_ctx ? &o_ctx->ctx : &server_ctx;
-SSL **sslp =     o_ctx ? &o_ctx->ssl : &server_ssl;
+SSL **sslp = o_ctx ? &o_ctx->ssl : (SSL **) &state_server.lib_state.lib_ssl;
 int *fdp = o_ctx ? &tls_out.active.sock : &tls_in.active.sock;


 if (*fdp < 0) return;  /* TLS was not active */
@@ -3802,8 +4354,8 @@ if (shutdown)
 if (!o_ctx)        /* server side */
   {
 #ifndef DISABLE_OCSP
-  sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free);
-  server_static_cbinfo->verify_stack = NULL;
+  sk_X509_pop_free(state_server.verify_stack, X509_free);
+  state_server.verify_stack = NULL;
 #endif


   receive_getc =    smtp_getc;
@@ -3818,9 +4370,7 @@ if (!o_ctx)        /* server side */
   /* Leave bits, peercert, cipher, peerdn, certificate_verified set, for logging */
   }


-SSL_CTX_free(*ctxp);
SSL_free(*sslp);
-*ctxp = NULL;
*sslp = NULL;
*fdp = -1;
}
@@ -3862,28 +4412,20 @@ while (*s != 0) { if (*s == '_') *s = '-'; s++; }

err = NULL;

-#ifdef EXIM_HAVE_OPENSSL_TLS_METHOD
-if (!(ctx = SSL_CTX_new(TLS_server_method())))
-#else
-if (!(ctx = SSL_CTX_new(SSLv23_server_method())))
-#endif
+if (lib_ctx_new(&ctx, NULL, &err) == OK)
   {
-  ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring));
-  return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring);
-  }
+  DEBUG(D_tls)
+    debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);


-DEBUG(D_tls)
-  debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);
+  if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
+    {
+    ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring));
+    err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s",
+            expciphers, ssl_errstring);
+    }


-if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
-  {
-  ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring));
-  err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s",
-              expciphers, ssl_errstring);
+  SSL_CTX_free(ctx);
   }
-
-SSL_CTX_free(ctx);
-
 return err;
 }


diff --git a/src/src/tls.c b/src/src/tls.c
index e5aabc6..ffcc859 100644
--- a/src/src/tls.c
+++ b/src/src/tls.c
@@ -36,6 +36,15 @@ functions from the OpenSSL or GNU TLS libraries. */

#ifndef MACRO_PREDEF

+static void tls_per_lib_daemon_init(void);
+static void tls_per_lib_daemon_tick(void);
+static void tls_server_creds_init(void);
+static void tls_server_creds_invalidate(void);
+static void tls_client_creds_init(transport_instance *, BOOL);
+static void tls_client_creds_invalidate(transport_instance *);
+
+
+
/* This module is compiled only when it is specifically requested in the
build-time configuration. However, some compilers don't like compiling empty
modules, so keep them happy with a dummy when skipping the rest. Make it
@@ -45,7 +54,9 @@ loops. */

 #ifdef DISABLE_TLS
 static void dummy(int x) { dummy(x-1); }
-#else
+#else    /* most of the rest of the file */
+
+const exim_tlslib_state    null_tls_preload = {0};


/* Static variables that are used for buffering data by both sets of
functions and the common functions below.
@@ -96,6 +107,154 @@ return TRUE;
}


+#ifdef EXIM_HAVE_INOTIFY
+/* Add the directory for a filename to the inotify handle, creating that if
+needed.  This is enough to see changes to files in that dir.
+Return boolean success.
+
+The word "system" fails, which is on the safe side as we don't know what
+directory it implies nor if the TLS library handles a watch for us.
+
+The string "system,cache" is recognised and explicitly accepted without
+setting a watch.  This permits the system CA bundle to be cached even though
+we have no way to tell when it gets modified by an update.
+
+We *might* try to run "openssl version -d" and set watches on the dir
+indicated in its output, plus the "certs" subdir of it (following
+synlimks for both).  But this is undocumented even for OpenSSL, and
+who knows what GnuTLS might be doing.
+
+A full set of caching including the CAs takes 35ms output off of the
+server tls_init() (GnuTLS, Fedora 32, 2018-class x86_64 laptop hardware).
+*/
+static BOOL
+tls_set_one_watch(const uschar * filename)
+{
+uschar * s;
+
+if (Ustrcmp(filename, "system,cache") == 0) return TRUE;
+
+if (!(s = Ustrrchr(filename, '/'))) return FALSE;
+s = string_copyn(filename, s - filename);
+DEBUG(D_tls) debug_printf("watch dir '%s'\n", s);
+
+if (inotify_add_watch(tls_watch_fd, CCS s,
+      IN_ONESHOT | IN_CLOSE_WRITE | IN_DELETE | IN_DELETE_SELF
+      | IN_MOVED_FROM | IN_MOVED_TO | IN_MOVE_SELF) >= 0)
+  return TRUE;
+DEBUG(D_tls) debug_printf("add_watch: %s\n", strerror(errno));
+return FALSE;
+}
+
+
+/* Create an inotify facility if needed.
+Then set watches on the dir containing the given file or (optionally)
+list of files.  Return boolean success. */
+
+static BOOL
+tls_set_watch(const uschar * filename, BOOL list)
+{
+rmark r;
+BOOL rc = FALSE;
+
+if (tls_watch_fd < 0 && (tls_watch_fd = inotify_init1(O_CLOEXEC)) < 0)
+  {
+  DEBUG(D_tls) debug_printf("inotify_init: %s\n", strerror(errno));
+  return FALSE;
+  }
+
+if (!filename || !*filename) return TRUE;
+
+r = store_mark();
+
+if (list)
+  {
+  int sep = 0;
+  for (uschar * s; s = string_nextinlist(&filename, &sep, NULL, 0); )
+    if (!(rc = tls_set_one_watch(s))) break;
+  }
+else
+  rc = tls_set_one_watch(filename);
+
+store_reset(r);
+return rc;
+}
+
+
+void
+tls_client_creds_reload(BOOL watch)
+{
+for(transport_instance * t = transports; t; t = t->next)
+  if (Ustrcmp(t->driver_name, "smtp") == 0)
+    {
+    tls_client_creds_invalidate(t);
+    tls_client_creds_init(t, watch);
+    }
+}
+
+static void
+tls_daemon_creds_reload(void)
+{
+tls_server_creds_invalidate();
+tls_server_creds_init();
+
+tls_client_creds_reload(TRUE);
+}
+
+
+/* Called, after a delay for multiple file ops to get done, from
+the daemon when any of the watches added (above) fire.
+
+Dump the set of watches and arrange to reload cached creds (which
+will set up new watches). */
+
+static void
+tls_watch_triggered(void)
+{
+DEBUG(D_tls) debug_printf("watch triggered\n");
+close(tls_watch_fd);
+tls_watch_fd = -1;
+
+tls_daemon_creds_reload();
+}
+
+
+/* Utility predicates for use by the per-library code */
+static BOOL
+opt_set_and_noexpand(const uschar * opt)
+{ return opt && *opt && Ustrchr(opt, '$') == NULL; }
+
+static BOOL
+opt_unset_or_noexpand(const uschar * opt)
+{ return !opt || Ustrchr(opt, '$') == NULL; }
+
+#endif    /* EXIM_HAVE_INOTIFY */
+
+
+/* Called every time round the daemon loop */
+
+void
+tls_daemon_tick(void)
+{
+tls_per_lib_daemon_tick();
+#ifdef EXIM_HAVE_INOTIFY
+if (tls_watch_trigger_time && time(NULL) >= tls_watch_trigger_time + 5)
+  {
+  tls_watch_trigger_time = 0;
+  tls_watch_triggered();
+  }
+#endif
+}
+
+/* Called once at daemon startup */
+
+void
+tls_daemon_init(void)
+{
+tls_per_lib_daemon_init();
+}
+
+
 /*************************************************
 *        Timezone environment flipping           *
 *************************************************/
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index cdee928..0a3d8f1 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -163,23 +163,12 @@ void smtp_transport_closedown(transport_instance *tblock) {}
 /* Default private options block for the smtp transport. */


 smtp_transport_options_block smtp_transport_option_defaults = {
-  .hosts =            NULL,
-  .fallback_hosts =        NULL,
-  .hostlist =            NULL,
-  .fallback_hostlist =        NULL,
+  /* All non-mentioned elements 0/NULL/FALSE */
   .helo_data =            US"$primary_hostname",
-  .interface =            NULL,
-  .port =            NULL,
   .protocol =            US"smtp",
-  .dscp =            NULL,
-  .serialize_hosts =        NULL,
-  .hosts_try_auth =        NULL,
-  .hosts_require_auth =        NULL,
   .hosts_try_chunking =        US"*",
 #ifdef SUPPORT_DANE
   .hosts_try_dane =        US"*",
-  .hosts_require_dane =        NULL,
-  .dane_require_tls_ciphers =    NULL,
 #endif
   .hosts_try_fastopen =        US"*",
 #ifndef DISABLE_PRDR
@@ -187,19 +176,6 @@ smtp_transport_options_block smtp_transport_option_defaults = {
 #endif
 #ifndef DISABLE_OCSP
   .hosts_request_ocsp =        US"*",               /* hosts_request_ocsp (except under DANE; tls_client_start()) */
-  .hosts_require_ocsp =        NULL,
-#endif
-  .hosts_require_tls =        NULL,
-  .hosts_avoid_tls =        NULL,
-  .hosts_verify_avoid_tls =    NULL,
-  .hosts_avoid_pipelining =    NULL,
-#ifndef DISABLE_PIPE_CONNECT
-  .hosts_pipe_connect =        NULL,
-#endif
-  .hosts_avoid_esmtp =        NULL,
-#ifndef DISABLE_TLS
-  .hosts_nopass_tls =        NULL,
-  .hosts_noproxy_tls =        NULL,
 #endif
   .command_timeout =        5*60,
   .connect_timeout =        5*60,
@@ -210,35 +186,15 @@ smtp_transport_options_block smtp_transport_option_defaults = {
   .hosts_max_try_hardlimit =    50,
   .message_linelength_limit =    998,
   .address_retry_include_sender = TRUE,
-  .allow_localhost =        FALSE,
-  .authenticated_sender_force =    FALSE,
-  .gethostbyname =        FALSE,
   .dns_qualify_single =        TRUE,
-  .dns_search_parents =        FALSE,
   .dnssec = { .request= US"*", .require=NULL },
   .delay_after_cutoff =        TRUE,
-  .hosts_override =        FALSE,
-  .hosts_randomize =        FALSE,
   .keepalive =            TRUE,
-  .lmtp_ignore_quota =        FALSE,
-  .expand_retry_include_ip_address =    NULL,
   .retry_include_ip_address =    TRUE,
-#ifdef SUPPORT_SOCKS
-  .socks_proxy =        NULL,
-#endif
 #ifndef DISABLE_TLS
-  .tls_certificate =        NULL,
-  .tls_crl =            NULL,
-  .tls_privatekey =        NULL,
-  .tls_require_ciphers =    NULL,
-  .tls_sni =            NULL,
   .tls_verify_certificates =    US"system",
   .tls_dh_min_bits =        EXIM_CLIENT_DH_DEFAULT_MIN_BITS,
   .tls_tempfail_tryclear =    TRUE,
-# ifndef DISABLE_TLS_RESUME
-  .tls_resumption_hosts =    NULL,
-# endif
-  .tls_verify_hosts =        NULL,
   .tls_try_verify_hosts =    US"*",
   .tls_verify_cert_hostnames =    US"*",
 #endif
@@ -247,24 +203,7 @@ smtp_transport_options_block smtp_transport_option_defaults = {
 #endif
 #ifndef DISABLE_DKIM
  .dkim =
-   {.dkim_domain =        NULL,
-    .dkim_identity =        NULL,
-    .dkim_private_key =        NULL,
-    .dkim_selector =        NULL,
-    .dkim_canon =        NULL,
-    .dkim_sign_headers =    NULL,
-    .dkim_strict =        NULL,
-    .dkim_hash =        US"sha256",
-    .dkim_timestamps =        NULL,
-    .dot_stuffed =        FALSE,
-    .force_bodyhash =        FALSE,
-# ifdef EXPERIMENTAL_ARC
-    .arc_signspec =        NULL,
-# endif
-    },
-# ifdef EXPERIMENTAL_ARC
-  .arc_sign =            NULL,
-# endif
+   { .dkim_hash =        US"sha256", },
 #endif
 };


diff --git a/src/src/transports/smtp.h b/src/src/transports/smtp.h
index 189ad9c..7feb811 100644
--- a/src/src/transports/smtp.h
+++ b/src/src/transports/smtp.h
@@ -13,6 +13,26 @@
 #define PENDING_OK      (PENDING + OK)



+#if !defined(DISABLE_TLS) && defined(EXIM_HAVE_INOTIFY)
+/* Flags structure for validity of TLS configuration */
+
+typedef struct {
+  BOOL conn_certs:1;        /* certificates etc. loaded */
+  BOOL cabundle:1;        /* CA certificates loaded */
+  BOOL crl:1;            /* CRL loaded */
+  BOOL pri_string:1;        /* cipher priority-string cache loaded */
+  BOOL dh:1;            /* Diffie-Helman params loaded */
+  BOOL ecdh:1;            /* EC Diffie-Helman params loaded */
+
+  BOOL ca_rdn_emulate:1;    /* do not advertise usable-cert list */
+  BOOL ocsp_hook:1;        /* need hshake callback on session */
+
+  void * libdata0;        /* library-dependent preloaded data */
+  void * libdata1;        /* library-dependent preloaded data */
+} exim_tlslib_state;
+#endif
+
+
 /* Private structure for the private options and other private data. */


 typedef struct {
@@ -105,6 +125,9 @@ typedef struct {
 #ifdef EXPERIMENTAL_ARC
   uschar    *arc_sign;
 #endif
+#if !defined(DISABLE_TLS) && defined(EXIM_HAVE_INOTIFY)
+  exim_tlslib_state tls_preload;
+#endif
 } smtp_transport_options_block;


 #define SOB (smtp_transport_options_block *)
diff --git a/test/confs/1102 b/test/confs/1102
new file mode 100644
index 0000000..2bab6e8
--- /dev/null
+++ b/test/confs/1102
@@ -0,0 +1,27 @@
+# Exim test configuration 1102
+
+.include DIR/aux-var/tls_conf_prefix
+
+primary_hostname = myhost.test.ex
+
+# ----- Main settings -----
+
+tls_advertise_hosts = *
+
+tls_certificate = DIR/tmp/certs/servercert
+tls_privatekey = DIR/tmp/certs/serverkey
+#tls_verify_certificates = DIR/aux-fixed/cert2
+tls_verify_certificates = system,cache
+
+queue_only
+log_selector = +millisec
+
+# --- ACL ---
+
+acl_smtp_rcpt = acl_check_rcpt
+
+begin acl
+acl_check_rcpt:
+    accept    logwrite = server cert: CN=${certextract{subject,CN}{$tls_in_ourcert}}
+
+# End
diff --git a/test/confs/1103 b/test/confs/1103
new file mode 100644
index 0000000..b937ee9
--- /dev/null
+++ b/test/confs/1103
@@ -0,0 +1,43 @@
+# Exim test configuration 1103
+
+.include DIR/aux-var/tls_conf_prefix
+
+primary_hostname = myhost.test.ex
+
+# ----- Main settings -----
+
+tls_advertise_hosts = *
+
+tls_certificate = DIR/tmp/certs/servercert
+tls_privatekey = DIR/tmp/certs/serverkey
+tls_try_verify_hosts = *
+tls_verify_certificates = DIR/aux-fixed/cert2
+#tls_verify_certificates = system,cache
+
+queue_only
+log_selector = +millisec
+
+# --- ACL ---
+
+acl_smtp_rcpt = accept
+
+# ----
+
+begin routers
+
+all:
+  driver = accept
+  transport = smtp
+
+begin transports
+
+smtp:
+  driver =        smtp
+  hosts =        127.0.0.1
+  allow_localhost
+  port =        PORT_D
+  tls_certificate =    DIR/aux-fixed/cert2
+  tls_verify_certificates =    DIR/aux-fixed/cert1
+  tls_verify_cert_hostnames =    :
+
+# End
diff --git a/test/confs/2025 b/test/confs/2025
index 8c08abe..5ddeb75 100644
--- a/test/confs/2025
+++ b/test/confs/2025
@@ -16,13 +16,8 @@ queue_only
 queue_run_in_order


 tls_advertise_hosts = *
-
 tls_require_ciphers = NORMAL:-VERS-ALL:+VERS-TLS1.2:-MAC-ALL:+SHA256
-
-# Set certificate only if server
-
-tls_certificate = ${if eq {SERVER}{server}{DIR/aux-fixed/cert1}fail}
-tls_privatekey = ${if eq {SERVER}{server}{DIR/aux-fixed/cert1}fail}
+tls_certificate =     DIR/aux-fixed/cert1



# ----- Routers -----
diff --git a/test/confs/2100 b/test/confs/2100
index 827d938..63a2f25 100644
--- a/test/confs/2100
+++ b/test/confs/2100
@@ -22,11 +22,13 @@ tls_advertise_hosts = *

# Set certificate only if server

-tls_certificate = ${if eq {SERVER}{server}{DIR/aux-fixed/cert1}fail}
-tls_privatekey = ${if eq {SERVER}{server}{DIR/aux-fixed/cert1}fail}
+#tls_certificate = ${if eq {SERVER}{server}{DIR/aux-fixed/cert1}fail}
+tls_certificate = DIR/aux-fixed/cert1
+#tls_privatekey = ${if eq {SERVER}{server}{DIR/aux-fixed/cert1}fail}

tls_verify_hosts = *
-tls_verify_certificates = ${if eq {SERVER}{server}{DIR/aux-fixed/cert2}fail}
+#tls_verify_certificates = ${if eq {SERVER}{server}{DIR/aux-fixed/cert2}fail}
+tls_verify_certificates = DIR/aux-fixed/cert2


 # ----- Routers -----
diff --git a/test/confs/2113 b/test/confs/2113
index fc2c722..b992747 100644
--- a/test/confs/2113
+++ b/test/confs/2113
@@ -66,7 +66,6 @@ send_to_server:
   port = PORT_D
   hosts_try_fastopen =    :
   hosts_noproxy_tls = PEX
-  tls_try_verify_hosts = :
   tls_verify_certificates = DIR/aux-fixed/cert1
   tls_verify_cert_hostnames = :


diff --git a/test/confs/4060 b/test/confs/4060
index f3aa84d..b6e0712 100644
--- a/test/confs/4060
+++ b/test/confs/4060
@@ -21,7 +21,11 @@ gecos_name = CALLER_NAME
dns_cname_loops = 9
chunking_advertise_hosts = OPT
tls_advertise_hosts = *
-tls_certificate = ${if eq {SERVER}{server}{DIR/aux-fixed/cert1}fail}
+tls_certificate = DIR/aux-fixed/cert1
+
+.ifdef _HAVE_TLS_CA_CACHE
+tls_verify_certificates = system,cache
+.endif

 .ifdef _HAVE_DMARC
 dmarc_tld_file =
diff --git a/test/log/1103 b/test/log/1103
new file mode 100644
index 0000000..28d97d3
--- /dev/null
+++ b/test/log/1103
@@ -0,0 +1,9 @@
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 <= CALLER@??? U=CALLER P=local S=sss
+
+******** SERVER ********
+2017-07-30 18:51:05.712 exim x.yz daemon started: pid=pppp, -q7s, listening for SMTP on port PORT_D
+2017-07-30 18:51:05.712 Start queue run: pid=pppp
+2017-07-30 18:51:05.712 10HmaY-0005vi-00 <= CALLER@??? H=localhost (myhost.test.ex) [127.0.0.1] P=esmtps X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes S=sss id=E10HmaX-0005vi-00@???
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 => test@??? R=all T=smtp H=127.0.0.1 [127.0.0.1] X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmaY-0005vi-00"
+2017-07-30 18:51:05.712 10HmaX-0005vi-00 Completed
+2017-07-30 18:51:05.712 End queue run: pid=pppp
diff --git a/test/runtest b/test/runtest
index 4972aed..f61b016 100755
--- a/test/runtest
+++ b/test/runtest
@@ -1067,6 +1067,24 @@ RESET_AFTER_EXTRA_LINE_READ:
     # this is timing-dependent
     next if /^OpenSSL: creating STEK$/;


+    # only OpenSSL speaks of these
+    next if /^TLS: preloading DH params for server/;
+    next if /^Diffie-Hellman initialized from default/;
+    next if /^TLS: preloading ECDH curve for server/;
+    next if /^ECDH OpenSSL [\d.+]+ temp key parameter settings: default selection$/;
+    next if /^watch dir '\/etc\/pki\/tls'$/;
+
+    # only GnuTLS speaks of these
+    next if /^GnuTLS global init required$/;
+    next if /^TLS: basic cred init, server/;
+    next if /^TLS: preloading cipher list for server: NULL$/;
+    s/^GnuTLS using default session cipher\/priority "NORMAL"$/TLS: not preloading cipher list for server/;
+    next if /^GnuTLS<2>: added \d+ protocols, \d+ ciphersuites, \d+ sig algos and \d+ groups into priority list$/;
+
+    # there happen in different orders for OpenSSL/GnuTLS/noTLS
+    next if /^TLS: not preloading (CA bundle|cipher list) for server$/;
+    next if /^TLS: not preloading server certs$/;
+
     # drop lookups
     next if /^Lookups \(built-in\):/;
     next if /^Loading lookup modules from/;
@@ -1275,6 +1293,14 @@ RESET_AFTER_EXTRA_LINE_READ:
     next if /^date:\w+,\{SP\}/;
     next if /^DKIM \[[^[]+\] (Header hash|b) computed:/;


+    # Timing variable over runs.  Collapse repeated memssages.
+    if (/notify triggered queue run/)
+      {
+      my $line = $_;
+      while (/notify triggered queue run/) { $_ = <IN>; }
+      $_ = $line . $_;
+      }
+
     # Not all platforms support TCP Fast Open, and the compile omits the check
     if (s/\S+ in hosts_try_fastopen\? (no \(option unset\)|no \(end of list\)|yes \(matched "\*"\))\n$//)
       {
diff --git a/test/scripts/1100-Basic-TLS/1101 b/test/scripts/1100-Basic-TLS/1101
index 0bcefa9..41407e8 100644
--- a/test/scripts/1100-Basic-TLS/1101
+++ b/test/scripts/1100-Basic-TLS/1101
@@ -1,4 +1,5 @@
-# TLS server: uncork in pipelining mode, fixed in bd95ffc2ba87fbd3c752df17bc8fd9c01586d45a
+# TLS server: uncork in pipelining mode
+# fixed in bd95ffc2ba87fbd3c752df17bc8fd9c01586d45a
 exim -DSERVER=server -bd -oX PORT_D:PORT_S
 ****
 client-anytls 127.0.0.1 PORT_D
diff --git a/test/scripts/1100-Basic-TLS/1102 b/test/scripts/1100-Basic-TLS/1102
new file mode 100644
index 0000000..862d26a
--- /dev/null
+++ b/test/scripts/1100-Basic-TLS/1102
@@ -0,0 +1,51 @@
+# TLS server: creds caching
+#
+#
+mkdir -p DIR/tmp/certs
+cp DIR/aux-fixed/cert1 DIR/tmp/certs/servercert
+cp DIR/aux-fixed/cert1 DIR/tmp/certs/serverkey
+#
+#exim -d-all+tls+receive+timestamp -DSERVER=server -bd -oX PORT_D
+exim -DSERVER=server -bd -oX PORT_D
+****
+client-anytls 127.0.0.1 PORT_D
+??? 220
+EHLO rhu.barb
+????250
+STARTTLS
+??? 220
+EHLO rhu.barb
+????250
+MAIL FROM:<>
+RCPT TO:test@???
+??? 250
+??? 250
+QUIT
+??? 221
+****
+sleep 1
+# Now overwrite the cert.  key?
+cp DIR/aux-fixed/exim-ca/example.com/server1.example.com/server1.example.com.pem DIR/tmp/certs/servercert
+cp DIR/aux-fixed/exim-ca/example.com/server1.example.com/server1.example.com.unlocked.key DIR/tmp/certs/serverkey
+# The watch mech waits 5 sec after the last trigger, so give that time to expire the send another message
+sleep 7
+client-anytls 127.0.0.1 PORT_D
+??? 220
+EHLO rhu.barb
+????250
+STARTTLS
+??? 220
+EHLO rhu.barb
+????250
+MAIL FROM:<>
+RCPT TO:test@???
+??? 250
+??? 250
+QUIT
+??? 221
+****
+#
+killdaemon
+#
+sudo rm -fr DIR/tmp
+no_msglog_check
diff --git a/test/scripts/1100-Basic-TLS/1103 b/test/scripts/1100-Basic-TLS/1103
new file mode 100644
index 0000000..de97e32
--- /dev/null
+++ b/test/scripts/1100-Basic-TLS/1103
@@ -0,0 +1,21 @@
+# TLS client: creds caching
+#
+#
+mkdir -p DIR/tmp/certs
+cp DIR/aux-fixed/cert1 DIR/tmp/certs/servercert
+cp DIR/aux-fixed/cert1 DIR/tmp/certs/serverkey
+#
+# load up one message in the queue
+exim test@???
+****
+#
+# start the daemon, with a queue-run interval
+# this will send the queued message and the receive will re-queue it
+#exim -d-all+tls+receive+timestamp -DSERVER=server -bd -q7s -oX PORT_D
+exim -DSERVER=server -bd -q7s -oX PORT_D
+****
+sleep 1
+killdaemon
+#
+sudo rm -fr DIR/tmp
+no_msglog_check