[exim-cvs] Use ALARM() to set deadline on reading the proxy …

Gitweb: https://git.exim.org/exim.git/commitdiff/db889856a56c1da9d18fc2f676b4aad2d45dc585

Commit:     db889856a56c1da9d18fc2f676b4aad2d45dc585
Parent:     f5107e39b94bd7d304dbe3ec766b5eecd647fe00
Author:     Heiko Schlittermann (HS12-RIPE) <hs@???>
AuthorDate: Fri Oct 2 08:19:12 2020 +0200
Committer:  Heiko Schlittermann (HS12-RIPE) <hs@???>
CommitDate: Sun Oct 4 11:23:35 2020 +0200

    Use ALARM() to set deadline on reading the proxy header (Bug 2656)
---
 src/src/macros.h  |  1 -
 src/src/smtp_in.c | 46 +++++++++++-----------------------------------
 2 files changed, 11 insertions(+), 36 deletions(-)

diff --git a/src/src/macros.h b/src/src/macros.h
index 82e50b5..c3f1c5d 100644
--- a/src/src/macros.h
+++ b/src/src/macros.h
@@ -201,7 +201,6 @@ host isn't speaking the protocol, and so is disallowed. Can be moved to
runtime configuration if per site settings become needed. */
#ifdef SUPPORT_PROXY
#define PROXY_NEGOTIATION_TIMEOUT_SEC 3
-#define PROXY_NEGOTIATION_TIMEOUT_USEC 0
#endif

/* Fixed option values for all PCRE functions */
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index 3941667..69eae3c 100644
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -1034,25 +1034,6 @@ had_command_sigterm = sig;

 #ifdef SUPPORT_PROXY
 /*************************************************
-*     Restore socket timeout to previous value   *
-*************************************************/
-/* If the previous value was successfully retrieved, restore
-it before returning control to the non-proxy routines
-
-Arguments: fd     - File descriptor for input
-           get_ok - Successfully retrieved previous values
-           tvtmp  - Time struct with previous values
-           vslen  - Length of time struct
-Returns:   none
-*/
-static void
-restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
-{
-if (get_ok == 0)
-  (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
-}
-
-/*************************************************
 *       Check if host is required proxy host     *
 *************************************************/
 /* The function determines if inbound host will be a regular smtp host
@@ -1128,7 +1109,7 @@ if (cr != NULL)

 while (capacity > 0)
   {
-  do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR);
+  do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout);
   if (ret == -1)
     return -1;
   have++;
@@ -1237,15 +1218,8 @@ struct timeval tvtmp;
 socklen_t vslen = sizeof(struct timeval);
 BOOL yield = FALSE;

-/* Save current socket timeout values */
-get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
-
-/* Proxy Protocol host must send header within a short time
-(default 3 seconds) or it's considered invalid */
-tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
-tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
-if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
- goto bad;
+os_non_restarting_signal(SIGALRM, command_timeout_handler);
+ALARM(PROXY_NEGOTIATION_TIMEOUT_SEC);

do
{
@@ -1255,7 +1229,7 @@ do
immediately with TLS handshake. */
ret = read(fd, &hdr, PROXY_INITIAL_READ);
}
- while (ret == -1 && errno == EINTR);
+ while (ret == -1 && errno == EINTR && !had_command_timeout);

 if (ret == -1)
   goto proxyfail;
@@ -1270,7 +1244,7 @@ if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
   do
     {
     retmore = read(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ);
-    } while (retmore == -1 && errno == EINTR);
+    } while (retmore == -1 && errno == EINTR && !had_command_timeout);
   if (retmore == -1)
     goto proxyfail;
   ret += retmore;
@@ -1307,7 +1281,7 @@ if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
     do
       {
       retmore = read(fd, (uschar*)&hdr + ret, size-ret);
-      } while (retmore == -1 && errno == EINTR);
+      } while (retmore == -1 && errno == EINTR && !had_command_timeout);
     if (retmore == -1)
       goto proxyfail;
     ret += retmore;
@@ -1535,7 +1509,8 @@ done:
 should cause a synchronization failure */

 proxyfail:
-  restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
+  DEBUG(D_receive) if (had_command_timeout)
+    debug_printf("Timeout while reading proxy header\n");

 bad:
   if (yield)
@@ -1551,6 +1526,7 @@ bad:
       debug_printf("Failure to extract proxied host, only QUIT allowed\n");
     }

+ALARM(0);
return;
}
#endif
@@ -2412,7 +2388,7 @@ TCP_SYN_RCV (as of 12.1) so no idea about data-use. */

 if (getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_FASTOPEN, &is_fastopen, &len) == 0)
   {
-  if (is_fastopen) 
+  if (is_fastopen)
     {
     DEBUG(D_receive)
       debug_printf("TFO mode connection (TCP_FASTOPEN getsockopt)\n");
@@ -5769,7 +5745,7 @@ while (done <= 0)
     /* If not serializing, do the exec right away. Otherwise, fork down
     into another process. */

-    if (  !smtp_etrn_serialize 
+    if (  !smtp_etrn_serialize
        || (pid = exim_fork(US"etrn-serialised-command")) == 0)
       {
       DEBUG(D_exec) debug_print_argv(argv);