Teach SMTP input sync check ("input sent too soon") about SMTP input buffering

8 files changed, 30 insertions, 16 deletions

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index a7b441e64..aca12ea00 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -73,6 +73,11 @@ JH/11 Bug 2104: Fix continued use of a transport connection with TLS.  In the
       which naturally failed, giving a failed delivery and bloating the retry
       database.  Investigation and fix prototype from Wolfgang Breyha.
 
+JH/12 Fix check on SMTP command input synchronisation.  Previously there were
+      false-negatives in the check that the sender had not preempted a response
+      or prompt from Exim (running as a server), due to that code's lack of
+      awareness of the SMTP input buferring.
+
 
 Exim version 4.89
 -----------------
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index 01c12caf6..8832908f3 100644
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -343,6 +343,9 @@ if (!smtp_enforce_sync || sender_host_address == NULL ||
     sender_host_notsocket || tls_in.active >= 0)
   return TRUE;
 
+if (smtp_inptr < smtp_inend)
+  return FALSE;
+
 fd = fileno(smtp_in);
 FD_ZERO(&fds);
 FD_SET(fd, &fds);
@@ -532,12 +535,15 @@ for(;;)
 
   if (!pipelining_advertised && !check_sync())
     {
+    unsigned n = smtp_inend - smtp_inptr;
+    if (n > 32) n = 32;
+
     incomplete_transaction_log(US"sync failure");
     log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
       "(next input sent too soon: pipelining was not advertised): "
       "rejected \"%s\" %s next input=\"%s\"",
       smtp_cmd_buffer, host_and_ident(TRUE),
-      string_printing(smtp_inptr));
+      string_printing(string_copyn(smtp_inptr, n)));
       (void) synprot_error(L_smtp_protocol_error, 554, NULL,
 	US"SMTP synchronization error");
     goto repeat_until_rset;
@@ -2863,10 +2869,13 @@ this synchronisation check is disabled. */
 
 if (!check_sync())
   {
+  unsigned n = smtp_inend - smtp_inptr;
+  if (n > 32) n = 32;
+
   log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
     "synchronization error (input sent without waiting for greeting): "
     "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
-    string_printing(smtp_inptr));
+    string_printing(string_copyn(smtp_inptr, n)));
   smtp_printf("554 SMTP synchronization error\r\n");
   return FALSE;
   }
diff --git a/test/log/0901 b/test/log/0901
index cd8c52e75..0297a8915 100644
--- a/test/log/0901
+++ b/test/log/0901
@@ -10,6 +10,6 @@
 1999-03-02 09:44:33 SMTP connection from (tester) [127.0.0.1] lost while reading message data
 1999-03-02 09:44:33 SMTP connection from (tester) [127.0.0.1] lost while reading message data
 1999-03-02 09:44:33 10HmbD-0005vi-00 <= someone8@some.domain H=(tester) [127.0.0.1] P=esmtp K S=sss for CALLER@test.ex
-1999-03-02 09:44:33 SMTP protocol synchronization error (next input sent too soon: pipelining was not advertised): rejected "bdat 1" H=(tester) [127.0.0.1] next input="bdat 87 last\r\n"
+1999-03-02 09:44:33 SMTP protocol synchronization error (next input sent too soon: pipelining was not advertised): rejected "BDAT 1" H=(tester) [127.0.0.1] next input="BDAT 87 last\r\n"
 1999-03-02 09:44:33 SMTP call from (tester) [127.0.0.1] dropped: too many syntax or protocol errors (last command was "From: Sam@random.com")
 1999-03-02 09:44:33 SMTP connection from (tester) [127.0.0.1] lost while reading message data (header)
diff --git a/test/rejectlog/0901 b/test/rejectlog/0901
index a7f8f0692..f75d9d270 100644
--- a/test/rejectlog/0901
+++ b/test/rejectlog/0901
@@ -1,6 +1,6 @@
 
 ******** SERVER ********
-1999-03-02 09:44:33 SMTP protocol synchronization error (next input sent too soon: pipelining was not advertised): rejected "bdat 1" H=(tester) [127.0.0.1] next input="bdat 87 last\r\n"
+1999-03-02 09:44:33 SMTP protocol synchronization error (next input sent too soon: pipelining was not advertised): rejected "BDAT 1" H=(tester) [127.0.0.1] next input="BDAT 87 last\r\n"
 Envelope-from: <someone9@some.domain>
 Envelope-to: <CALLER@test.ex>
 1999-03-02 09:44:33 SMTP call from (tester) [127.0.0.1] dropped: too many syntax or protocol errors (last command was "From: Sam@random.com")
diff --git a/test/scripts/0000-Basic/0901 b/test/scripts/0000-Basic/0901
index 9908d5ecd..5e88c5ae9 100644
--- a/test/scripts/0000-Basic/0901
+++ b/test/scripts/0000-Basic/0901
@@ -243,12 +243,12 @@ ehlo tester
 ??? 250-8BITMIME
 ??? 250-CHUNKING
 ??? 250 HELP
-mail from:someone9@some.domain
+MAIL FROM:someone9@some.domain
 ??? 250
-rcpt to:CALLER@test.ex
+RCPT TO:CALLER@test.ex
 ??? 250
-bdat 1\r\nTbdat 87 last
-To: Susan@random.com
+BDAT 1\r\nTBDAT 87 last
+o: Susan@random.com
 From: Sam@random.com
 Subject: This is a bodyless test message
 
diff --git a/test/scripts/2000-GnuTLS/2031 b/test/scripts/2000-GnuTLS/2031
index 65b529093..76186b5e4 100644
--- a/test/scripts/2000-GnuTLS/2031
+++ b/test/scripts/2000-GnuTLS/2031
@@ -6,14 +6,14 @@ exim -DSERVER=server -bd -oX PORT_D
 exim CALLER@test.ex
 Test message.
 ****
-millisleep 500
+millisleep 700
 #
 #
 # Extended: server uses SNI to choose certificate
 exim abcd@test.ex
 Test message.
 ****
-millisleep 500
+millisleep 700
 #
 #
 killdaemon
diff --git a/test/scripts/5730-OCSP-GnuTLS-events/5730 b/test/scripts/5730-OCSP-GnuTLS-events/5730
index d22a1aa1f..11c3a867f 100644
--- a/test/scripts/5730-OCSP-GnuTLS-events/5730
+++ b/test/scripts/5730-OCSP-GnuTLS-events/5730
@@ -21,7 +21,7 @@ exim -bd -oX PORT_D -DSERVER=server \
 exim norequire@test.ex
 test message.
 ****
-millisleep 500
+millisleep 700
 #
 #
 #
@@ -30,7 +30,7 @@ millisleep 500
 exim nostaple@test.ex
 test message.
 ****
-millisleep 500
+millisleep 700
 #
 #
 #
diff --git a/test/stdout/0901 b/test/stdout/0901
index 99eb81231..a982ac8b6 100644
--- a/test/stdout/0901
+++ b/test/stdout/0901
@@ -324,14 +324,14 @@ Connecting to 127.0.0.1 port 1225 ... connected
 <<< 250-CHUNKING
 ??? 250 HELP
 <<< 250 HELP
->>> mail from:someone9@some.domain
+>>> MAIL FROM:someone9@some.domain
 ??? 250
 <<< 250 OK
->>> rcpt to:CALLER@test.ex
+>>> RCPT TO:CALLER@test.ex
 ??? 250
 <<< 250 Accepted
->>> bdat 1\r\nTbdat 87 last
->>> To: Susan@random.com
+>>> BDAT 1\r\nTBDAT 87 last
+>>> o: Susan@random.com
 >>> From: Sam@random.com
 >>> Subject: This is a bodyless test message
 >>>