Gitweb:
https://git.exim.org/exim.git/commitdiff/df0dc54a7666ef64b8a6681ab7b50a4836905203
Commit: df0dc54a7666ef64b8a6681ab7b50a4836905203
Parent: 04f8f0c709efd5fc366fc2623919c8b568dd57d3
Author: Jeremy Harris <jgh146exb@???>
AuthorDate: Tue Mar 21 20:02:18 2023 +0000
Committer: Jeremy Harris <jgh146exb@???>
CommitDate: Tue Mar 21 20:03:25 2023 +0000
Move Proxy-Protocol impl to separate srcfile
---
src/OS/Makefile-Base | 3 +-
src/scripts/MakeLinks | 2 +-
src/src/functions.h | 10 +-
src/src/globals.c | 2 +-
src/src/globals.h | 2 +-
src/src/proxy.c | 529 ++++++++++++++++++++++++++++++++++++++++++++++++++
src/src/smtp_in.c | 526 +------------------------------------------------
7 files changed, 551 insertions(+), 523 deletions(-)
diff --git a/src/OS/Makefile-Base b/src/OS/Makefile-Base
index 29c037401..d00ab9404 100644
--- a/src/OS/Makefile-Base
+++ b/src/OS/Makefile-Base
@@ -508,7 +508,7 @@ OBJ_EXIM = acl.o base64.o child.o crypt16.o daemon.o dbfn.o debug.o deliver.o \
directory.o dns.o drtables.o enq.o exim.o expand.o filter.o \
filtertest.o globals.o dkim.o dkim_transport.o dnsbl.o hash.o \
header.o host.o host_address.o ip.o log.o lss.o match.o md5.o moan.o \
- os.o parse.o priv.o queue.o \
+ os.o parse.o priv.o proxy.o queue.o \
rda.o readconf.o receive.o retry.o rewrite.o rfc2047.o regex_cache.o \
route.o search.o sieve.o smtp_in.o smtp_out.o spool_in.o spool_out.o \
std-crypto.o store.o string.o tls.o tod.o transport.o tree.o verify.o \
@@ -824,6 +824,7 @@ moan.o: $(HDRS) moan.c
os.o: $(HDRS) $(OS_C_INCLUDES) os.c
parse.o: $(HDRS) parse.c
priv.o: $(HDRS) priv.c
+proxy.o: $(HDRS) proxy.c
queue.o: $(HDRS) queue.c
rda.o: $(HDRS) rda.c
readconf.o: $(HDRS) readconf.c
diff --git a/src/scripts/MakeLinks b/src/scripts/MakeLinks
index 6e0b65f5d..af6138063 100755
--- a/src/scripts/MakeLinks
+++ b/src/scripts/MakeLinks
@@ -104,7 +104,7 @@ for f in blob.h dbfunctions.h exim.h functions.h globals.h \
deliver.c directory.c dns.c dnsbl.c drtables.c dummies.c enq.c exim.c \
exim_dbmbuild.c exim_dbutil.c exim_lock.c expand.c filter.c filtertest.c \
globals.c hash.c header.c host.c host_address.c ip.c log.c lss.c match.c md5.c moan.c \
- parse.c perl.c priv.c queue.c rda.c readconf.c receive.c retry.c rewrite.c \
+ parse.c perl.c priv.c proxy.c queue.c rda.c readconf.c receive.c retry.c rewrite.c \
regex_cache.c rfc2047.c route.c search.c setenv.c environment.c \
sieve.c smtp_in.c smtp_out.c spool_in.c spool_out.c std-crypto.c store.c \
string.c tls.c tlscert-gnu.c tlscert-openssl.c tls-cipher-stdname.c \
diff --git a/src/src/functions.h b/src/src/functions.h
index 896122a69..76392f304 100644
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -400,9 +400,9 @@ extern const uschar *parse_quote_2047(const uschar *, int, const uschar *,
extern const uschar *parse_date_time(const uschar *str, time_t *t);
extern void priv_drop_temp(const uid_t, const gid_t);
extern void priv_restore(void);
-extern int vaguely_random_number(int);
-#ifndef DISABLE_TLS
-extern int vaguely_random_number_fallback(int);
+#ifdef SUPPORT_PROXY
+extern BOOL proxy_protocol_host(void);
+extern void proxy_protocol_setup(void);
#endif
extern BOOL queue_action(uschar *, int, uschar **, int, int);
@@ -658,6 +658,10 @@ extern void unspool_mbox(void);
extern gstring *utf8_version_report(gstring *);
#endif
+extern int vaguely_random_number(int);
+#ifndef DISABLE_TLS
+extern int vaguely_random_number_fallback(int);
+#endif
extern int verify_address(address_item *, FILE *, int, int, int, int,
uschar *, uschar *, BOOL *);
extern int verify_check_dnsbl(int, const uschar **, uschar **);
diff --git a/src/src/globals.c b/src/src/globals.c
index c6bacc02f..539bae00e 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -387,7 +387,7 @@ BOOL mua_wrapper = FALSE;
BOOL preserve_message_logs = FALSE;
BOOL print_topbitchars = FALSE;
BOOL prod_requires_admin = TRUE;
-#if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS)
+#if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMETAL_XCLIENT)
BOOL proxy_session = FALSE;
#endif
diff --git a/src/src/globals.h b/src/src/globals.h
index 81d052fd5..e216b9208 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -821,7 +821,7 @@ extern uschar *process_log_path; /* Alternate path */
extern const uschar *process_purpose; /* for debug output */
extern BOOL prod_requires_admin; /* TRUE if prodding requires admin */
-#if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS)
+#if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMENTAL_XCLIENT)
extern uschar *hosts_proxy; /* Hostlist which (require) use proxy protocol */
extern uschar *proxy_external_address; /* IP of remote interface of proxy */
extern int proxy_external_port; /* Port on remote interface of proxy */
diff --git a/src/src/proxy.c b/src/src/proxy.c
new file mode 100644
index 000000000..fbce11163
--- /dev/null
+++ b/src/src/proxy.c
@@ -0,0 +1,529 @@
+/*************************************************
+* Exim - an Internet mail transport agent *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2020 - 2023 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/************************************************
+* Proxy-Protocol support *
+************************************************/
+
+#include "exim.h"
+
+#ifdef SUPPORT_PROXY
+/*************************************************
+* Check if host is required proxy host *
+*************************************************/
+/* The function determines if inbound host will be a regular smtp host
+or if it is configured that it must use Proxy Protocol. A local
+connection cannot.
+
+Arguments: none
+Returns: boolean for Proxy Protocol needed
+*/
+
+BOOL
+proxy_protocol_host(void)
+{
+int rc;
+
+if ( sender_host_address
+ && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
+ sender_host_address, NULL)) == OK)
+ {
+ DEBUG(D_receive)
+ debug_printf("Detected proxy protocol configured host\n");
+ proxy_session = TRUE;
+ }
+return proxy_session;
+}
+
+
+/*************************************************
+* Read data until newline or end of buffer *
+*************************************************/
+/* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
+read an entire buffer and assume there will be nothing past a proxy protocol
+header. Our approach normally is to use stdio, but again that relies upon
+"STARTTLS\r\n" and a server response before the client starts TLS handshake, or
+reading _nothing_ before client TLS handshake. So we don't want to use the
+usual buffering reads which may read enough to block TLS starting.
+
+So unfortunately we're down to "read one byte at a time, with a syscall each,
+and expect a little overhead", for all proxy-opened connections which are v1,
+just to handle the TLS-on-connect case. Since SSL functions wrap the
+underlying fd, we can't assume that we can feed them any already-read content.
+
+We need to know where to read to, the max capacity, and we'll read until we
+get a CR and one more character. Let the caller scream if it's CR+!LF.
+
+Return the amount read.
+*/
+
+static int
+swallow_until_crlf(int fd, uschar *base, int already, int capacity)
+{
+uschar *to = base + already;
+uschar *cr;
+int have = 0;
+int ret;
+int last = 0;
+
+/* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
+up through the \r; for the _normal_ case, we haven't yet seen the \r. */
+
+cr = memchr(base, '\r', already);
+if (cr != NULL)
+ {
+ if ((cr - base) < already - 1)
+ {
+ /* \r and presumed \n already within what we have; probably not
+ actually proxy protocol, but abort cleanly. */
+ return 0;
+ }
+ /* \r is last character read, just need one more. */
+ last = 1;
+ }
+
+while (capacity > 0)
+ {
+ do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
+ if (ret == -1)
+ return -1;
+ have++;
+ if (last)
+ return have;
+ if (*to == '\r')
+ last = 1;
+ capacity--;
+ to++;
+ }
+
+/* reached end without having room for a final newline, abort */
+errno = EOVERFLOW;
+return -1;
+}
+
+
+static void
+proxy_debug(uschar * buf, unsigned start, unsigned end)
+{
+debug_printf("PROXY<<");
+while (start < end) debug_printf(" %02x", buf[start++]);
+debug_printf("\n");
+}
+
+
+/*************************************************
+* Setup host for proxy protocol *
+*************************************************/
+/* The function configures the connection based on a header from the
+inbound host to use Proxy Protocol. The specification is very exact
+so exit with an error if do not find the exact required pieces. This
+includes an incorrect number of spaces separating args.
+
+Arguments: none
+Returns: Boolean success
+*/
+
+void
+proxy_protocol_setup(void)
+{
+union {
+ struct {
+ uschar line[108];
+ } v1;
+ struct {
+ uschar sig[12];
+ uint8_t ver_cmd;
+ uint8_t fam;
+ uint16_t len;
+ union {
+ struct { /* TCP/UDP over IPv4, len = 12 */
+ uint32_t src_addr;
+ uint32_t dst_addr;
+ uint16_t src_port;
+ uint16_t dst_port;
+ } ip4;
+ struct { /* TCP/UDP over IPv6, len = 36 */
+ uint8_t src_addr[16];
+ uint8_t dst_addr[16];
+ uint16_t src_port;
+ uint16_t dst_port;
+ } ip6;
+ struct { /* AF_UNIX sockets, len = 216 */
+ uschar src_addr[108];
+ uschar dst_addr[108];
+ } unx;
+ } addr;
+ } v2;
+} hdr;
+
+/* Temp variables used in PPv2 address:port parsing */
+uint16_t tmpport;
+char tmpip[INET_ADDRSTRLEN];
+struct sockaddr_in tmpaddr;
+char tmpip6[INET6_ADDRSTRLEN];
+struct sockaddr_in6 tmpaddr6;
+
+/* We can't read "all data until end" because while SMTP is
+server-speaks-first, the TLS handshake is client-speaks-first, so for
+TLS-on-connect ports the proxy protocol header will usually be immediately
+followed by a TLS handshake, and with N TLS libraries, we can't reliably
+reinject data for reading by those. So instead we first read "enough to be
+safely read within the header, and figure out how much more to read".
+For v1 we will later read to the end-of-line, for v2 we will read based upon
+the stated length.
+
+The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
+data is needed total. For v1, where the line looks like:
+PROXY TCPn L3src L3dest SrcPort DestPort \r\n
+
+However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
+We seem to support that. So, if we read 14 octets then we can tell if we're
+v2 or v1. If we're v1, we can continue reading as normal.
+
+If we're v2, we can't slurp up the entire header. We need the length in the
+15th & 16th octets, then to read everything after that.
+
+So to safely handle v1 and v2, with client-sent-first supported correctly,
+we have to do a minimum of 3 read calls, not 1. Eww.
+*/
+
+# define PROXY_INITIAL_READ 14
+# define PROXY_V2_HEADER_SIZE 16
+# if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
+# error Code bug in sizes of data to read for proxy usage
+# endif
+
+int get_ok = 0;
+int size, ret;
+int fd = fileno(smtp_in);
+const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
+uschar * iptype; /* To display debug info */
+socklen_t vslen = sizeof(struct timeval);
+BOOL yield = FALSE;
+
+ALARM(proxy_protocol_timeout);
+
+do
+ {
+ /* The inbound host was declared to be a Proxy Protocol host, so
+ don't do a PEEK into the data, actually slurp up enough to be
+ "safe". Can't take it all because TLS-on-connect clients follow
+ immediately with TLS handshake. */
+ ret = read(fd, &hdr, PROXY_INITIAL_READ);
+ } while (ret == -1 && errno == EINTR && !had_command_timeout);
+
+if (ret == -1)
+ goto proxyfail;
+DEBUG(D_receive) proxy_debug(US &hdr, 0, ret);
+
+/* For v2, handle reading the length, and then the rest. */
+if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
+ {
+ int retmore;
+ uint8_t ver;
+
+ DEBUG(D_receive) debug_printf("v2\n");
+
+ /* First get the length fields. */
+ do
+ {
+ retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
+ } while (retmore == -1 && errno == EINTR && !had_command_timeout);
+ if (retmore == -1)
+ goto proxyfail;
+ DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
+
+ ret += retmore;
+
+ ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
+
+ /* May 2014: haproxy combined the version and command into one byte to
+ allow two full bytes for the length field in order to proxy SSL
+ connections. SSL Proxy is not supported in this version of Exim, but
+ must still separate values here. */
+
+ if (ver != 0x02)
+ {
+ DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
+ goto proxyfail;
+ }
+
+ /* The v2 header will always be 16 bytes per the spec. */
+ size = 16 + ntohs(hdr.v2.len);
+ DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
+ size, (int)sizeof(hdr));
+
+ /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
+ amount that we need. Double-check that the size is not unreasonable, then
+ get the rest. */
+ if (size > sizeof(hdr))
+ {
+ DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
+ goto proxyfail;
+ }
+
+ do
+ {
+ do
+ {
+ retmore = read(fd, (uschar*)&hdr + ret, size-ret);
+ } while (retmore == -1 && errno == EINTR && !had_command_timeout);
+ if (retmore == -1)
+ goto proxyfail;
+ DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
+ ret += retmore;
+ DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
+ } while (ret < size);
+
+ } /* end scope for getting rest of data for v2 */
+
+/* At this point: if PROXYv2, we've read the exact size required for all data;
+if PROXYv1 then we've read "less than required for any valid line" and should
+read the rest". */
+
+if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
+ {
+ uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
+
+ switch (cmd)
+ {
+ case 0x01: /* PROXY command */
+ switch (hdr.v2.fam)
+ {
+ case 0x11: /* TCPv4 address type */
+ iptype = US"IPv4";
+ tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
+ inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
+ if (!string_is_ip_address(US tmpip, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
+ goto proxyfail;
+ }
+ proxy_local_address = sender_host_address;
+ sender_host_address = string_copy(US tmpip);
+ tmpport = ntohs(hdr.v2.addr.ip4.src_port);
+ proxy_local_port = sender_host_port;
+ sender_host_port = tmpport;
+ /* Save dest ip/port */
+ tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
+ inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
+ if (!string_is_ip_address(US tmpip, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
+ goto proxyfail;
+ }
+ proxy_external_address = string_copy(US tmpip);
+ tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
+ proxy_external_port = tmpport;
+ goto done;
+ case 0x21: /* TCPv6 address type */
+ iptype = US"IPv6";
+ memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
+ inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
+ if (!string_is_ip_address(US tmpip6, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
+ goto proxyfail;
+ }
+ proxy_local_address = sender_host_address;
+ sender_host_address = string_copy(US tmpip6);
+ tmpport = ntohs(hdr.v2.addr.ip6.src_port);
+ proxy_local_port = sender_host_port;
+ sender_host_port = tmpport;
+ /* Save dest ip/port */
+ memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
+ inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
+ if (!string_is_ip_address(US tmpip6, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
+ goto proxyfail;
+ }
+ proxy_external_address = string_copy(US tmpip6);
+ tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
+ proxy_external_port = tmpport;
+ goto done;
+ default:
+ DEBUG(D_receive)
+ debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
+ hdr.v2.fam);
+ goto proxyfail;
+ }
+ /* Unsupported protocol, keep local connection address */
+ break;
+ case 0x00: /* LOCAL command */
+ /* Keep local connection address for LOCAL */
+ iptype = US"local";
+ break;
+ default:
+ DEBUG(D_receive)
+ debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
+ goto proxyfail;
+ }
+ }
+else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
+ {
+ uschar *p;
+ uschar *end;
+ uschar *sp; /* Utility variables follow */
+ int tmp_port;
+ int r2;
+ char *endc;
+
+ /* get the rest of the line */
+ r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
+ if (r2 == -1)
+ goto proxyfail;
+ ret += r2;
+
+ p = string_copy(hdr.v1.line);
+ end = memchr(p, '\r', ret - 1);
+
+ if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
+ {
+ DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
+ goto proxyfail;
+ }
+ *end = '\0'; /* Terminate the string */
+ size = end + 2 - p; /* Skip header + CRLF */
+ DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
+ DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
+ /* Step through the string looking for the required fields. Ensure
+ strict adherence to required formatting, exit for any error. */
+ p += 5;
+ if (!isspace(*(p++)))
+ {
+ DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
+ goto proxyfail;
+ }
+ if (!Ustrncmp(p, CCS"TCP4", 4))
+ iptype = US"IPv4";
+ else if (!Ustrncmp(p,CCS"TCP6", 4))
+ iptype = US"IPv6";
+ else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
+ {
+ iptype = US"Unknown";
+ goto done;
+ }
+ else
+ {
+ DEBUG(D_receive) debug_printf("Invalid TCP type\n");
+ goto proxyfail;
+ }
+
+ p += Ustrlen(iptype);
+ if (!isspace(*(p++)))
+ {
+ DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
+ goto proxyfail;
+ }
+ /* Find the end of the arg */
+ if ((sp = Ustrchr(p, ' ')) == NULL)
+ {
+ DEBUG(D_receive)
+ debug_printf("Did not find proxied src %s\n", iptype);
+ goto proxyfail;
+ }
+ *sp = '\0';
+ if(!string_is_ip_address(p, NULL))
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxied src arg is not an %s address\n", iptype);
+ goto proxyfail;
+ }
+ proxy_local_address = sender_host_address;
+ sender_host_address = p;
+ p = sp + 1;
+ if ((sp = Ustrchr(p, ' ')) == NULL)
+ {
+ DEBUG(D_receive)
+ debug_printf("Did not find proxy dest %s\n", iptype);
+ goto proxyfail;
+ }
+ *sp = '\0';
+ if(!string_is_ip_address(p, NULL))
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxy dest arg is not an %s address\n", iptype);
+ goto proxyfail;
+ }
+ proxy_external_address = p;
+ p = sp + 1;
+ if ((sp = Ustrchr(p, ' ')) == NULL)
+ {
+ DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
+ goto proxyfail;
+ }
+ *sp = '\0';
+ tmp_port = strtol(CCS p, &endc, 10);
+ if (*endc || tmp_port == 0)
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxied src port '%s' not an integer\n", p);
+ goto proxyfail;
+ }
+ proxy_local_port = sender_host_port;
+ sender_host_port = tmp_port;
+ p = sp + 1;
+ if ((sp = Ustrchr(p, '\0')) == NULL)
+ {
+ DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
+ goto proxyfail;
+ }
+ tmp_port = strtol(CCS p, &endc, 10);
+ if (*endc || tmp_port == 0)
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxy dest port '%s' not an integer\n", p);
+ goto proxyfail;
+ }
+ proxy_external_port = tmp_port;
+ /* Already checked for /r /n above. Good V1 header received. */
+ }
+else
+ {
+ /* Wrong protocol */
+ DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
+ (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
+ goto proxyfail;
+ }
+
+done:
+ DEBUG(D_receive)
+ debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
+ yield = proxy_session;
+
+/* Don't flush any potential buffer contents. Any input on proxyfail
+should cause a synchronization failure */
+
+proxyfail:
+ DEBUG(D_receive) if (had_command_timeout)
+ debug_printf("Timeout while reading proxy header\n");
+
+bad:
+ if (yield)
+ {
+ sender_host_name = NULL;
+ (void) host_name_lookup();
+ host_build_sender_fullhost();
+ }
+ else
+ {
+ f.proxy_session_failed = TRUE;
+ DEBUG(D_receive)
+ debug_printf("Failure to extract proxied host, only QUIT allowed\n");
+ }
+
+ALARM(0);
+return;
+}
+#endif /*SUPPORT_PROXY*/
+
+/* vi: aw ai sw=2
+*/
+/* End of proxy.c */
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index 5b2df7805..7a45772ce 100644
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -1110,518 +1110,6 @@ had_command_sigterm = sig;
-#ifdef SUPPORT_PROXY
-/*************************************************
-* Check if host is required proxy host *
-*************************************************/
-/* The function determines if inbound host will be a regular smtp host
-or if it is configured that it must use Proxy Protocol. A local
-connection cannot.
-
-Arguments: none
-Returns: bool
-*/
-
-static BOOL
-check_proxy_protocol_host()
-{
-int rc;
-
-if ( sender_host_address
- && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
- sender_host_address, NULL)) == OK)
- {
- DEBUG(D_receive)
- debug_printf("Detected proxy protocol configured host\n");
- proxy_session = TRUE;
- }
-return proxy_session;
-}
-
-
-/*************************************************
-* Read data until newline or end of buffer *
-*************************************************/
-/* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
-read an entire buffer and assume there will be nothing past a proxy protocol
-header. Our approach normally is to use stdio, but again that relies upon
-"STARTTLS\r\n" and a server response before the client starts TLS handshake, or
-reading _nothing_ before client TLS handshake. So we don't want to use the
-usual buffering reads which may read enough to block TLS starting.
-
-So unfortunately we're down to "read one byte at a time, with a syscall each,
-and expect a little overhead", for all proxy-opened connections which are v1,
-just to handle the TLS-on-connect case. Since SSL functions wrap the
-underlying fd, we can't assume that we can feed them any already-read content.
-
-We need to know where to read to, the max capacity, and we'll read until we
-get a CR and one more character. Let the caller scream if it's CR+!LF.
-
-Return the amount read.
-*/
-
-static int
-swallow_until_crlf(int fd, uschar *base, int already, int capacity)
-{
-uschar *to = base + already;
-uschar *cr;
-int have = 0;
-int ret;
-int last = 0;
-
-/* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
-up through the \r; for the _normal_ case, we haven't yet seen the \r. */
-
-cr = memchr(base, '\r', already);
-if (cr != NULL)
- {
- if ((cr - base) < already - 1)
- {
- /* \r and presumed \n already within what we have; probably not
- actually proxy protocol, but abort cleanly. */
- return 0;
- }
- /* \r is last character read, just need one more. */
- last = 1;
- }
-
-while (capacity > 0)
- {
- do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
- if (ret == -1)
- return -1;
- have++;
- if (last)
- return have;
- if (*to == '\r')
- last = 1;
- capacity--;
- to++;
- }
-
-/* reached end without having room for a final newline, abort */
-errno = EOVERFLOW;
-return -1;
-}
-
-
-static void
-proxy_debug(uschar * buf, unsigned start, unsigned end)
-{
-debug_printf("PROXY<<");
-while (start < end) debug_printf(" %02x", buf[start++]);
-debug_printf("\n");
-}
-
-
-/*************************************************
-* Setup host for proxy protocol *
-*************************************************/
-/* The function configures the connection based on a header from the
-inbound host to use Proxy Protocol. The specification is very exact
-so exit with an error if do not find the exact required pieces. This
-includes an incorrect number of spaces separating args.
-
-Arguments: none
-Returns: Boolean success
-*/
-
-static void
-setup_proxy_protocol_host()
-{
-union {
- struct {
- uschar line[108];
- } v1;
- struct {
- uschar sig[12];
- uint8_t ver_cmd;
- uint8_t fam;
- uint16_t len;
- union {
- struct { /* TCP/UDP over IPv4, len = 12 */
- uint32_t src_addr;
- uint32_t dst_addr;
- uint16_t src_port;
- uint16_t dst_port;
- } ip4;
- struct { /* TCP/UDP over IPv6, len = 36 */
- uint8_t src_addr[16];
- uint8_t dst_addr[16];
- uint16_t src_port;
- uint16_t dst_port;
- } ip6;
- struct { /* AF_UNIX sockets, len = 216 */
- uschar src_addr[108];
- uschar dst_addr[108];
- } unx;
- } addr;
- } v2;
-} hdr;
-
-/* Temp variables used in PPv2 address:port parsing */
-uint16_t tmpport;
-char tmpip[INET_ADDRSTRLEN];
-struct sockaddr_in tmpaddr;
-char tmpip6[INET6_ADDRSTRLEN];
-struct sockaddr_in6 tmpaddr6;
-
-/* We can't read "all data until end" because while SMTP is
-server-speaks-first, the TLS handshake is client-speaks-first, so for
-TLS-on-connect ports the proxy protocol header will usually be immediately
-followed by a TLS handshake, and with N TLS libraries, we can't reliably
-reinject data for reading by those. So instead we first read "enough to be
-safely read within the header, and figure out how much more to read".
-For v1 we will later read to the end-of-line, for v2 we will read based upon
-the stated length.
-
-The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
-data is needed total. For v1, where the line looks like:
-PROXY TCPn L3src L3dest SrcPort DestPort \r\n
-
-However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
-We seem to support that. So, if we read 14 octets then we can tell if we're
-v2 or v1. If we're v1, we can continue reading as normal.
-
-If we're v2, we can't slurp up the entire header. We need the length in the
-15th & 16th octets, then to read everything after that.
-
-So to safely handle v1 and v2, with client-sent-first supported correctly,
-we have to do a minimum of 3 read calls, not 1. Eww.
-*/
-
-# define PROXY_INITIAL_READ 14
-# define PROXY_V2_HEADER_SIZE 16
-# if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
-# error Code bug in sizes of data to read for proxy usage
-# endif
-
-int get_ok = 0;
-int size, ret;
-int fd = fileno(smtp_in);
-const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
-uschar * iptype; /* To display debug info */
-socklen_t vslen = sizeof(struct timeval);
-BOOL yield = FALSE;
-
-os_non_restarting_signal(SIGALRM, command_timeout_handler);
-ALARM(proxy_protocol_timeout);
-
-do
- {
- /* The inbound host was declared to be a Proxy Protocol host, so
- don't do a PEEK into the data, actually slurp up enough to be
- "safe". Can't take it all because TLS-on-connect clients follow
- immediately with TLS handshake. */
- ret = read(fd, &hdr, PROXY_INITIAL_READ);
- } while (ret == -1 && errno == EINTR && !had_command_timeout);
-
-if (ret == -1)
- goto proxyfail;
-DEBUG(D_receive) proxy_debug(US &hdr, 0, ret);
-
-/* For v2, handle reading the length, and then the rest. */
-if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
- {
- int retmore;
- uint8_t ver;
-
- DEBUG(D_receive) debug_printf("v2\n");
-
- /* First get the length fields. */
- do
- {
- retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
- } while (retmore == -1 && errno == EINTR && !had_command_timeout);
- if (retmore == -1)
- goto proxyfail;
- DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
-
- ret += retmore;
-
- ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
-
- /* May 2014: haproxy combined the version and command into one byte to
- allow two full bytes for the length field in order to proxy SSL
- connections. SSL Proxy is not supported in this version of Exim, but
- must still separate values here. */
-
- if (ver != 0x02)
- {
- DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
- goto proxyfail;
- }
-
- /* The v2 header will always be 16 bytes per the spec. */
- size = 16 + ntohs(hdr.v2.len);
- DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
- size, (int)sizeof(hdr));
-
- /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
- amount that we need. Double-check that the size is not unreasonable, then
- get the rest. */
- if (size > sizeof(hdr))
- {
- DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
- goto proxyfail;
- }
-
- do
- {
- do
- {
- retmore = read(fd, (uschar*)&hdr + ret, size-ret);
- } while (retmore == -1 && errno == EINTR && !had_command_timeout);
- if (retmore == -1)
- goto proxyfail;
- DEBUG(D_receive) proxy_debug(US &hdr, ret, ret + retmore);
- ret += retmore;
- DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
- } while (ret < size);
-
- } /* end scope for getting rest of data for v2 */
-
-/* At this point: if PROXYv2, we've read the exact size required for all data;
-if PROXYv1 then we've read "less than required for any valid line" and should
-read the rest". */
-
-if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
- {
- uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
-
- switch (cmd)
- {
- case 0x01: /* PROXY command */
- switch (hdr.v2.fam)
- {
- case 0x11: /* TCPv4 address type */
- iptype = US"IPv4";
- tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
- inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
- if (!string_is_ip_address(US tmpip, NULL))
- {
- DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
- goto proxyfail;
- }
- proxy_local_address = sender_host_address;
- sender_host_address = string_copy(US tmpip);
- tmpport = ntohs(hdr.v2.addr.ip4.src_port);
- proxy_local_port = sender_host_port;
- sender_host_port = tmpport;
- /* Save dest ip/port */
- tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
- inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
- if (!string_is_ip_address(US tmpip, NULL))
- {
- DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
- goto proxyfail;
- }
- proxy_external_address = string_copy(US tmpip);
- tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
- proxy_external_port = tmpport;
- goto done;
- case 0x21: /* TCPv6 address type */
- iptype = US"IPv6";
- memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
- inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
- if (!string_is_ip_address(US tmpip6, NULL))
- {
- DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
- goto proxyfail;
- }
- proxy_local_address = sender_host_address;
- sender_host_address = string_copy(US tmpip6);
- tmpport = ntohs(hdr.v2.addr.ip6.src_port);
- proxy_local_port = sender_host_port;
- sender_host_port = tmpport;
- /* Save dest ip/port */
- memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
- inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
- if (!string_is_ip_address(US tmpip6, NULL))
- {
- DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
- goto proxyfail;
- }
- proxy_external_address = string_copy(US tmpip6);
- tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
- proxy_external_port = tmpport;
- goto done;
- default:
- DEBUG(D_receive)
- debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
- hdr.v2.fam);
- goto proxyfail;
- }
- /* Unsupported protocol, keep local connection address */
- break;
- case 0x00: /* LOCAL command */
- /* Keep local connection address for LOCAL */
- iptype = US"local";
- break;
- default:
- DEBUG(D_receive)
- debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
- goto proxyfail;
- }
- }
-else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
- {
- uschar *p;
- uschar *end;
- uschar *sp; /* Utility variables follow */
- int tmp_port;
- int r2;
- char *endc;
-
- /* get the rest of the line */
- r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
- if (r2 == -1)
- goto proxyfail;
- ret += r2;
-
- p = string_copy(hdr.v1.line);
- end = memchr(p, '\r', ret - 1);
-
- if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
- {
- DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
- goto proxyfail;
- }
- *end = '\0'; /* Terminate the string */
- size = end + 2 - p; /* Skip header + CRLF */
- DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
- DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
- /* Step through the string looking for the required fields. Ensure
- strict adherence to required formatting, exit for any error. */
- p += 5;
- if (!isspace(*(p++)))
- {
- DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
- goto proxyfail;
- }
- if (!Ustrncmp(p, CCS"TCP4", 4))
- iptype = US"IPv4";
- else if (!Ustrncmp(p,CCS"TCP6", 4))
- iptype = US"IPv6";
- else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
- {
- iptype = US"Unknown";
- goto done;
- }
- else
- {
- DEBUG(D_receive) debug_printf("Invalid TCP type\n");
- goto proxyfail;
- }
-
- p += Ustrlen(iptype);
- if (!isspace(*(p++)))
- {
- DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
- goto proxyfail;
- }
- /* Find the end of the arg */
- if ((sp = Ustrchr(p, ' ')) == NULL)
- {
- DEBUG(D_receive)
- debug_printf("Did not find proxied src %s\n", iptype);
- goto proxyfail;
- }
- *sp = '\0';
- if(!string_is_ip_address(p, NULL))
- {
- DEBUG(D_receive)
- debug_printf("Proxied src arg is not an %s address\n", iptype);
- goto proxyfail;
- }
- proxy_local_address = sender_host_address;
- sender_host_address = p;
- p = sp + 1;
- if ((sp = Ustrchr(p, ' ')) == NULL)
- {
- DEBUG(D_receive)
- debug_printf("Did not find proxy dest %s\n", iptype);
- goto proxyfail;
- }
- *sp = '\0';
- if(!string_is_ip_address(p, NULL))
- {
- DEBUG(D_receive)
- debug_printf("Proxy dest arg is not an %s address\n", iptype);
- goto proxyfail;
- }
- proxy_external_address = p;
- p = sp + 1;
- if ((sp = Ustrchr(p, ' ')) == NULL)
- {
- DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
- goto proxyfail;
- }
- *sp = '\0';
- tmp_port = strtol(CCS p, &endc, 10);
- if (*endc || tmp_port == 0)
- {
- DEBUG(D_receive)
- debug_printf("Proxied src port '%s' not an integer\n", p);
- goto proxyfail;
- }
- proxy_local_port = sender_host_port;
- sender_host_port = tmp_port;
- p = sp + 1;
- if ((sp = Ustrchr(p, '\0')) == NULL)
- {
- DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
- goto proxyfail;
- }
- tmp_port = strtol(CCS p, &endc, 10);
- if (*endc || tmp_port == 0)
- {
- DEBUG(D_receive)
- debug_printf("Proxy dest port '%s' not an integer\n", p);
- goto proxyfail;
- }
- proxy_external_port = tmp_port;
- /* Already checked for /r /n above. Good V1 header received. */
- }
-else
- {
- /* Wrong protocol */
- DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
- (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
- goto proxyfail;
- }
-
-done:
- DEBUG(D_receive)
- debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
- yield = proxy_session;
-
-/* Don't flush any potential buffer contents. Any input on proxyfail
-should cause a synchronization failure */
-
-proxyfail:
- DEBUG(D_receive) if (had_command_timeout)
- debug_printf("Timeout while reading proxy header\n");
-
-bad:
- if (yield)
- {
- sender_host_name = NULL;
- (void) host_name_lookup();
- host_build_sender_fullhost();
- }
- else
- {
- f.proxy_session_failed = TRUE;
- DEBUG(D_receive)
- debug_printf("Failure to extract proxied host, only QUIT allowed\n");
- }
-
-ALARM(0);
-return;
-}
-#endif /*SUPPORT_PROXY*/
-
/*************************************************
* Read one command line *
*************************************************/
@@ -3030,14 +2518,20 @@ if (!f.sender_host_unknown)
if (smtp_batched_input) return TRUE;
+#if defined(SUPPORT_PROXY) || defined(SUPPORT_SOCKS) || defined(EXPERIMETAL_XCLIENT)
+proxy_session = FALSE;
+#endif
+
+#ifdef SUPPORT_PROXY
/* If valid Proxy Protocol source is connecting, set up session.
Failure will not allow any SMTP function other than QUIT. */
-#ifdef SUPPORT_PROXY
-proxy_session = FALSE;
f.proxy_session_failed = FALSE;
-if (check_proxy_protocol_host())
- setup_proxy_protocol_host();
+if (proxy_protocol_host())
+ {
+ os_non_restarting_signal(SIGALRM, command_timeout_handler);
+ proxy_protocol_setup();
+ }
#endif
/* Run the connect ACL if it exists */
