Verify callout/random: repoen connection if error after random rcpt attempt. Bug 495

3 files changed, 99 insertions, 10 deletions

diff --git a/src/src/verify.c b/src/src/verify.c
index ec75ce5ce..c1fb17767 100644
--- a/src/src/verify.c
+++ b/src/src/verify.c
@@ -388,12 +388,9 @@ else
   log the fact, but carry on without randomming. */
 
   if (callout_random && callout_random_local_part != NULL)
-    {
-    random_local_part = expand_string(callout_random_local_part);
-    if (random_local_part == NULL)
+    if (!(random_local_part = expand_string(callout_random_local_part)))
       log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
         "callout_random_local_part: %s", expand_string_message);
-    }
 
   /* Default the connect and overall callout timeouts if not set, and record the
   time we are starting so that we can enforce it. */
@@ -635,14 +632,14 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
     outblock.cmd_count = 0;
     outblock.authenticating = FALSE;
 
-    /* Reset the parameters of a TLS session */
-    tls_out.cipher = tls_out.peerdn = tls_out.peercert = NULL;
-
     /* Connect to the host; on failure, just loop for the next one, but we
     set the error for the last one. Use the callout_connect timeout. */
 
     tls_retry_connection:
 
+    /* Reset the parameters of a TLS session */
+    tls_out.cipher = tls_out.peerdn = tls_out.peercert = NULL;
+
     inblock.sock = outblock.sock =
       smtp_connect(host, host_af, port, interface, callout_connect, TRUE, NULL
 #ifdef EXPERIMENTAL_EVENT
@@ -1009,10 +1006,15 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
 
         /* Otherwise, cache a real negative response, and get back to the right
         state to send RCPT. Unless there's some problem such as a dropped
-        connection, we expect to succeed, because the commands succeeded above. */
+        connection, we expect to succeed, because the commands succeeded above.
+	However, some servers drop the connection after responding to  an
+	invalid recipient, so on (any) error we drop and remake the connection.
+	*/
 
         else if (errno == 0)
           {
+	  /* This would be ok for 1st rcpt a cutthrough, but no way to
+	  handle a subsequent.  So refuse to support any */
 	  cancel_cutthrough_connection("random-recipient");
 
           if (randombuffer[0] == '5')
@@ -1027,6 +1029,22 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
               from_address) >= 0 &&
             smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
               '2', callout);
+
+	  if (!done)
+	    {
+	    HDEBUG(D_acl|D_v)
+	      debug_printf("problem after random/rset/mfrom; reopen conn\n");
+	    random_local_part = NULL;
+#ifdef SUPPORT_TLS
+	    tls_close(FALSE, TRUE);
+#endif
+	    (void)close(inblock.sock);
+#ifdef EXPERIMENTAL_EVENT
+	    (void) event_raise(addr->transport->event_action,
+			      US"tcp:close", NULL);
+#endif
+	    goto tls_retry_connection;
+	    }
           }
         else done = FALSE;    /* Some timeout/connection problem */
         }                     /* Random check */
@@ -1060,8 +1078,9 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
 
         if (done && pm_mailfrom != NULL)
           {
-          /*XXX not suitable for cutthrough - we cannot afford to do an RSET
-	  and lose the original mail-from */
+          /* Could possibly shift before main verify, just above, and be ok
+	  for cutthrough.  But no way to handle a subsequent rcpt, so just
+	  refuse any */
 	cancel_cutthrough_connection("postmaster verify");
   	HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
 
diff --git a/test/scripts/0000-Basic/0473 b/test/scripts/0000-Basic/0473
index 3d17e5ed0..df613c4b7 100644
--- a/test/scripts/0000-Basic/0473
+++ b/test/scripts/0000-Basic/0473
@@ -150,6 +150,34 @@ rcpt to: r11@two.test.ex
 quit
 ****
 dump callout
+#
+# callout target dumps after random-reject
+server PORT_S 2
+220 Server ready
+EHLO
+250 OK
+MAIL FROM
+250 OK
+RCPT TO
+550 Bad receipient, dropping conn
+>*eof
+220 Server ready
+EHLO
+250 OK
+MAIL FROM
+250 OK
+RCPT TO
+250 OK
+QUIT
+250 OK
+****
+exim -DUSE_SENDER=,random -bs
+ehlo xxxx
+mail from: x12@three.test.ex
+rcpt to: r12@three.test.ex
+quit
+****
+dump callout
 server PORT_S
 220 Server ready
 EHLO
diff --git a/test/stdout/0473 b/test/stdout/0473
index 9fff9a601..59ed36d6a 100644
--- a/test/stdout/0473
+++ b/test/stdout/0473
@@ -107,6 +107,26 @@
 250-PIPELINING

 250 HELP

 250 OK

+250 Accepted

+221 the.local.host.name closing connection

++++++++++++++++++++++++++++
+07-Mar-2000 12:21:52 r12@three.test.ex callout=accept
+07-Mar-2000 12:21:52 r1@test.ex callout=accept
+07-Mar-2000 12:21:52 r1@test.ex/<postmaster@the.local.host.name> callout=accept
+07-Mar-2000 12:21:52 r1@test.ex/<s1@test.ex> callout=accept
+07-Mar-2000 12:21:52 r1@test.ex/<s2@test.ex> callout=accept
+07-Mar-2000 12:21:52 r9@test.ex/<x9@test.ex> callout=reject
+07-Mar-2000 12:21:52 test.ex callout=accept postmaster=unknown random=unknown
+07-Mar-2000 12:21:52 three.test.ex callout=accept postmaster=unknown random=reject (07-Mar-2000 12:21:52)
+07-Mar-2000 12:21:52 two.test.ex callout=accept postmaster=unknown random=accept (07-Mar-2000 12:21:52)
+07-Mar-2000 12:21:52 x9@test.ex callout=reject
+220 the.local.host.name ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000

+250-the.local.host.name Hello CALLER at xxxx

+250-SIZE 52428800

+250-8BITMIME

+250-PIPELINING

+250 HELP

+250 OK

 451 Could not complete recipient verify callout

 221 the.local.host.name closing connection

 220 the.local.host.name ESMTP Exim x.yz Tue, 2 Mar 1999 09:44:33 +0000

@@ -221,6 +241,28 @@ EHLO the.local.host.name
 250 OK
 MAIL FROM:<>
 250 OK
+RCPT TO:<the.local.host.name--testing@three.test.ex>
+550 Bad receipient, dropping conn
+>*eof
+Listening on port 1224 ... 
+Connection request from [127.0.0.1]
+220 Server ready
+EHLO the.local.host.name
+250 OK
+MAIL FROM:<>
+250 OK
+RCPT TO:<r12@three.test.ex>
+250 OK
+QUIT
+250 OK
+End of script
+Listening on port 1224 ... 
+Connection request from [127.0.0.1]
+220 Server ready
+EHLO the.local.host.name
+250 OK
+MAIL FROM:<>
+250 OK
 RCPT TO:<r11@two.test.ex>
 *sleep 2
 End of script