[exim-cvs] Fix getting non-TLS QUIT in FIN segment

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Autor: Exim Git Commits Mailing List
Fecha:  
A: exim-cvs
Asunto: [exim-cvs] Fix getting non-TLS QUIT in FIN segment
Gitweb: https://git.exim.org/exim.git/commitdiff/97cfe3942f67200f77f6ae9b302409075e4e5792
Commit:     97cfe3942f67200f77f6ae9b302409075e4e5792
Parent:     81df60f6229e66dc8306e55ea2103e577782d984
Author:     Jeremy Harris <jgh146exb@???>
AuthorDate: Fri Jan 22 19:58:54 2021 +0000
Committer:  Jeremy Harris <jgh146exb@???>
CommitDate: Fri Jan 22 21:58:25 2021 +0000


    Fix getting non-TLS QUIT in FIN segment


    Linux was behaving oddly with the TCP_CORK method, and using MSG_MORE
    is one fewer syscall.
---
 src/src/tls-gnu.c         |  2 ++
 src/src/tls-openssl.c     |  2 ++
 src/src/transports/smtp.c | 40 ++++++++++++++++++----------------------
 test/runtest              |  2 +-
 test/stderr/0143          |  2 +-
 test/stderr/0388          |  2 +-
 test/stderr/1157          |  6 +++---
 test/stderr/2035          |  2 +-
 test/stderr/2135          |  2 +-
 test/stderr/4052          |  2 +-
 test/stderr/4520          |  2 +-
 11 files changed, 32 insertions(+), 32 deletions(-)


diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index b14bca4..46547d7 100644
--- a/src/src/tls-gnu.c
+++ b/src/src/tls-gnu.c
@@ -3513,6 +3513,8 @@ tls_support * tlsp = state->tlsp;

if (!tlsp || tlsp->active.sock < 0) return; /* TLS was not active */

+tls_write(ct_ctx, NULL, 0, FALSE);    /* flush write buffer */
+
 if (shutdown)
   {
   DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n",
diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c
index 0dfd8e0..0d653a4 100644
--- a/src/src/tls-openssl.c
+++ b/src/src/tls-openssl.c
@@ -4147,6 +4147,8 @@ int *fdp = o_ctx ? &tls_out.active.sock : &tls_in.active.sock;


if (*fdp < 0) return; /* TLS was not active */

+tls_write(ct_ctx, NULL, 0, FALSE);    /* flush write buffer */
+
 if (shutdown)
   {
   int rc;
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index eb6b774..0a6bfde 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -4380,35 +4380,21 @@ propagate it from the initial
   }


/* End off tidily with QUIT unless the connection has died or the socket has
-been passed to another process. There has been discussion on the net about what
-to do after sending QUIT. The wording of the RFC suggests that it is necessary
-to wait for a response, but on the other hand, there isn't anything one can do
-with an error response, other than log it. Exim used to do that. However,
-further discussion suggested that it is positively advantageous not to wait for
-the response, but to close the session immediately. This is supposed to move
-the TCP/IP TIME_WAIT state from the server to the client, thereby removing some
-load from the server. (Hosts that are both servers and clients may not see much
-difference, of course.) Further discussion indicated that this was safe to do
-on Unix systems which have decent implementations of TCP/IP that leave the
-connection around for a while (TIME_WAIT) after the application has gone away.
-This enables the response sent by the server to be properly ACKed rather than
-timed out, as can happen on broken TCP/IP implementations on other OS.
-
-This change is being made on 31-Jul-98. After over a year of trouble-free
-operation, the old commented-out code was removed on 17-Sep-99. */
+been passed to another process. */

 SEND_QUIT:
 if (sx->send_quit)
-  {
-#ifdef EXIM_TCP_CORK
-  (void) setsockopt(sx->cctx.sock, IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
-#endif
-  (void)smtp_write_command(sx, SCMD_FLUSH, "QUIT\r\n");
-  }
+            /* Use _MORE to get QUIT in FIN segment */
+  (void)smtp_write_command(sx, SCMD_MORE, "QUIT\r\n");


END_OFF:

 #ifndef DISABLE_TLS
+# ifdef EXIM_TCP_CORK
+if (sx->cctx.tls_ctx)    /* Use _CORK to get TLS Close Notify in FIN segment */
+  (void) setsockopt(sx->cctx.sock, IPPROTO_TCP, EXIM_TCP_CORK, US &on, sizeof(on));
+# endif
+
 tls_close(sx->cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
 sx->cctx.tls_ctx = NULL;
 #endif
@@ -4426,7 +4412,17 @@ case continue_more won't get set. */
 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  SMTP(close)>>\n");
 if (sx->send_quit)
   {
+  /* This flushes data queued in the socket, being the QUIT and any TLS Close,
+  sending them along with the client FIN flag.  Us (we hope) sending FIN first
+  means we (client) take the TIME_WAIT state, so the server (which likely has a
+  higher connection rate) does no have to. */
+
   shutdown(sx->cctx.sock, SHUT_WR);
+
+  /* Wait for (we hope) ack of our QUIT, and a server FIN.  Discard any data
+  received, then discard the socket.  Any packet received after then, or receive
+  data still in the socket, will get a RST - hence the pause/drain. */
+
   millisleep(20);
   testharness_pause_ms(200);
   if (fcntl(sx->cctx.sock, F_SETFL, O_NONBLOCK) == 0)
diff --git a/test/runtest b/test/runtest
index ba2450c..c52afce 100755
--- a/test/runtest
+++ b/test/runtest
@@ -1289,7 +1289,7 @@ RESET_AFTER_EXTRA_LINE_READ:
     next if /\w+ in keep_environment\? (yes|no)/;


     # Sizes vary with test hostname
-    s/^cmd buf flush \d+ bytes$/cmd buf flush ddd bytes/;
+    s/^cmd buf flush \d+ bytes/cmd buf flush ddd bytes/;


     # Spool filesystem free space changes on different systems.
     s/^((?:spool|log) directory space =) -?\d+K (inodes =)\s*-?\d+/$1 nnnnnK $2 nnnnn/;
diff --git a/test/stderr/0143 b/test/stderr/0143
index e91e97a..f7f14f6 100644
--- a/test/stderr/0143
+++ b/test/stderr/0143
@@ -50,7 +50,7 @@ transport_check_waiting entered
  no messages waiting for 127.0.0.1
 transport_check_waiting: FALSE
   SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
   SMTP(close)>>
 Leaving my_smtp transport
 LOG: MAIN
diff --git a/test/stderr/0388 b/test/stderr/0388
index 0b66b63..e23c903 100644
--- a/test/stderr/0388
+++ b/test/stderr/0388
@@ -99,7 +99,7 @@ LOG: MAIN
   H=127.0.0.1 [127.0.0.1]: SMTP error from remote mail server after RCPT TO:<x@y>: 451 Temporary error
 added retry item for R:x@y: errno=-44 more_errno=dd,A flags=0
   SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
   SMTP(close)>>
 set_process_info: pppp delivering 10HmaX-0005vi-00: just tried 127.0.0.1 [127.0.0.1]:PORT_S for x@y: result OK
 address match test: subject=*@127.0.0.1 pattern=*
diff --git a/test/stderr/1157 b/test/stderr/1157
index 368ccc0..3335276 100644
--- a/test/stderr/1157
+++ b/test/stderr/1157
@@ -73,7 +73,7 @@ cmd buf flush ddd bytes
   SMTP<< 354 Enter message, ending with "." on a line by itself
   SMTP<< 250 OK id=10HmbC-0005vi-00
   SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
   SMTP(close)>>

>>>>>>>>>>>>>>>> Exim pid=pppp (tls-proxy) terminating with rc=0 >>>>>>>>>>>>>>>>

LOG: MAIN
@@ -159,7 +159,7 @@ cmd buf flush ddd bytes
SMTP<< 354 Enter message, ending with "." on a line by itself
SMTP<< 250 OK id=10HmbI-0005vi-00
SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
SMTP(close)>>
>>>>>>>>>>>>>>>> Exim pid=pppp (tls-proxy) terminating with rc=0 >>>>>>>>>>>>>>>>

LOG: MAIN
@@ -282,7 +282,7 @@ cmd buf flush ddd bytes
SMTP<< 354 Enter message, ending with "." on a line by itself
SMTP<< 250 OK id=10HmbO-0005vi-00
SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
SMTP(close)>>
LOG: MAIN
=> usery@??? R=client T=send_to_server H=127.0.0.1 [127.0.0.1]* X=TLS1.x:ke-RSA-AES256-SHAnnn:xxx CV=yes C="250 OK id=10HmbO-0005vi-00"
diff --git a/test/stderr/2035 b/test/stderr/2035
index 5a69f57..75c7a82 100644
--- a/test/stderr/2035
+++ b/test/stderr/2035
@@ -63,7 +63,7 @@ writing data block fd=dddd size=sss timeout=300
SMTP<< 250 OK id=10HmaY-0005vi-00
ok=1 send_quit=1 send_rset=0 continue_more=0 yield=0 first_address is NULL
SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
SMTP(close)>>
>>>>>>>>>>>>>>>> Exim pid=pppp (tls-proxy) terminating with rc=0 >>>>>>>>>>>>>>>>

Leaving t1 transport
diff --git a/test/stderr/2135 b/test/stderr/2135
index 5a69f57..75c7a82 100644
--- a/test/stderr/2135
+++ b/test/stderr/2135
@@ -63,7 +63,7 @@ writing data block fd=dddd size=sss timeout=300
SMTP<< 250 OK id=10HmaY-0005vi-00
ok=1 send_quit=1 send_rset=0 continue_more=0 yield=0 first_address is NULL
SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
SMTP(close)>>
>>>>>>>>>>>>>>>> Exim pid=pppp (tls-proxy) terminating with rc=0 >>>>>>>>>>>>>>>>

Leaving t1 transport
diff --git a/test/stderr/4052 b/test/stderr/4052
index d4866ed..22f0558 100644
--- a/test/stderr/4052
+++ b/test/stderr/4052
@@ -57,7 +57,7 @@ transport_check_waiting entered
no messages waiting for 127.0.0.1
transport_check_waiting: FALSE
SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
SMTP(close)>>
Leaving smtp transport
LOG: MAIN
diff --git a/test/stderr/4520 b/test/stderr/4520
index 6087e66..d88fc98 100644
--- a/test/stderr/4520
+++ b/test/stderr/4520
@@ -49,7 +49,7 @@ dkim-signature:v=1;{SP}a=rsa-sha256;{SP}q=dns/txt;{SP}c=relaxed/relaxed;{SP}d=te
DKIM [test.ex] Header sha256 computed: 241e16230df5723d899cfae9474c6b376a2ab1f81d1094e358f50ffd0e0067b3
SMTP<< 250 OK id=10HmbL-0005vi-00
SMTP>> QUIT
-cmd buf flush ddd bytes
+cmd buf flush ddd bytes (more expected)
SMTP(close)>>
LOG: MAIN
=> d@??? R=client T=send_to_server H=ip4.ip4.ip4.ip4 [ip4.ip4.ip4.ip4] C="250 OK id=10HmbL-0005vi-00"