- Fix loopback problems with Postfix 1.x

5 files changed, 71 insertions, 14 deletions

diff --git a/AUTHORS b/AUTHORS
index 82374c0..a80252d 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -1,9 +1,11 @@
 AUTHOR:
 Nate Nielsen <nielsen@memberwebs.com>
 
+CONTRIBUTORS:
+Andreas Steinmetz <ast@domdv.de>
+
 PATCHES:
 Berk D. Demir <demir@meteksan.net.tr>
 João Carlos Mendes Luís <jcmendes@int.gov.br>
 Jasper Slits <jasper@insiders.nl>
-Andreas Steinmetz <ast@domdv.de>
 Yamamoto Takao <takao@oakat.org>
diff --git a/ChangeLog b/ChangeLog
index 7c49094..ee9ecc3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,9 @@
 0.7
   - Added support for ESMTP [Andreas Steinmetz]
-  - Fixed other bugs
+  - Fixed crash when too many connections established
+  - Announce ourselves as 'clamsmtp' in EHLO/HELO responses which fixes 'loopback'
+    problems with certain versions of Postfix 1.x
+  - Fixed other minor bugs
 
 0.6
   - Proper adding of customized header [Berk D. Demir]
diff --git a/common/smtppass.c b/common/smtppass.c
index 984744d..a0e59cf 100644
--- a/common/smtppass.c
+++ b/common/smtppass.c
@@ -91,6 +91,7 @@ clamsmtp_thread_t;
 
 #define SMTP_DATA           "DATA" CRLF
 #define SMTP_BANNER         "220 clamsmtp" CRLF
+#define SMTP_HELO_RSP       "250 clamsmtp" CRLF
 #define SMTP_DELIMS         "\r\n\t :-"
 
 #define ESMTP_PIPELINE      "PIPELINING"
@@ -674,11 +675,13 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
 {
     char logline[LINE_LENGTH];
     int r, ret = 0;
-    int first_rsp = 1;
-    int filter_ehlo = 0;
 	fd_set mask;
     int neterror = 0;
 
+    int first_rsp = 1;      /* The first 220 response from server to be filtered */
+    int filter_ehlo = 0;    /* Filtering parts of an EHLO extensions response */
+    int filter_host = 0;    /* Next response is 250 hostname, which we change */
+
     ASSERT(ctx->clam != -1 && ctx->server != -1);
     logline[0] = 0;
 
@@ -720,9 +723,9 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
                 continue;
             }
 
-            /* Only valid after an EHLO command */
-            if(filter_ehlo)
-                filter_ehlo = 0;
+            /* Only valid after EHLO or HELO commands */
+            filter_ehlo = 0;
+            filter_host = 0;
 
             /* Handle the DATA section via our AV checker */
             if(is_first_word(ctx->line, DATA_CMD, KL(DATA_CMD)))
@@ -757,6 +760,7 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
             {
                 messagex(ctx, LOG_DEBUG, "filtering EHLO response");
                 filter_ehlo = 1;
+                filter_host = 1;
 
                 /* A new message */
                 logline[0] = 0;
@@ -768,6 +772,8 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
              */
             else if(is_first_word(ctx->line, HELO_CMD, KL(HELO_CMD)))
             {
+                filter_host = 1;
+
                 /* A new message line */
                 logline[0] = 0;
             }
@@ -849,6 +855,26 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
             }
 
             /*
+             * Certain mail servers (Postfix 1.x in particular) do a loop check
+             * on the 250 response after a EHLO or HELO. This is where we
+             * filter that to prevent loopback errors.
+             */
+            if(filter_host)
+            {
+                filter_host = 0;
+
+                if(check_first_word(ctx->line, OK_RSP, KL(OK_RSP), SMTP_DELIMS) > 0)
+                {
+                    messagex(ctx, LOG_DEBUG, "intercepting host response");
+
+                    if(write_data(ctx, &(ctx->client), SMTP_HELO_RSP) == -1)
+                        RETURN(-1);
+
+                    continue;
+                }
+            }
+
+            /*
              * Filter out any EHLO responses that we can't or don't want
              * to support. For example pipelining or TLS.
              */
diff --git a/configure.in b/configure.in
index f87c179..8087d2b 100644
--- a/configure.in
+++ b/configure.in
@@ -36,8 +36,8 @@ dnl  Nate Nielsen <nielsen@memberwebs.com>
 dnl
 
 dnl Process this file with autoconf to produce a configure script.
-AC_INIT(clamsmtp, 0.6.90, nielsen@memberwebs.com)
-AM_INIT_AUTOMAKE(clamsmtp, 0.6.90)
+AC_INIT(clamsmtp, 0.6.91, nielsen@memberwebs.com)
+AM_INIT_AUTOMAKE(clamsmtp, 0.6.91)
 
 LDFLAGS="$LDFLAGS -L/usr/local/lib"
 CFLAGS="$CFLAGS -I/usr/local/include"
diff --git a/src/clamsmtpd.c b/src/clamsmtpd.c
index 984744d..a0e59cf 100644
--- a/src/clamsmtpd.c
+++ b/src/clamsmtpd.c
@@ -91,6 +91,7 @@ clamsmtp_thread_t;
 
 #define SMTP_DATA           "DATA" CRLF
 #define SMTP_BANNER         "220 clamsmtp" CRLF
+#define SMTP_HELO_RSP       "250 clamsmtp" CRLF
 #define SMTP_DELIMS         "\r\n\t :-"
 
 #define ESMTP_PIPELINE      "PIPELINING"
@@ -674,11 +675,13 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
 {
     char logline[LINE_LENGTH];
     int r, ret = 0;
-    int first_rsp = 1;
-    int filter_ehlo = 0;
 	fd_set mask;
     int neterror = 0;
 
+    int first_rsp = 1;      /* The first 220 response from server to be filtered */
+    int filter_ehlo = 0;    /* Filtering parts of an EHLO extensions response */
+    int filter_host = 0;    /* Next response is 250 hostname, which we change */
+
     ASSERT(ctx->clam != -1 && ctx->server != -1);
     logline[0] = 0;
 
@@ -720,9 +723,9 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
                 continue;
             }
 
-            /* Only valid after an EHLO command */
-            if(filter_ehlo)
-                filter_ehlo = 0;
+            /* Only valid after EHLO or HELO commands */
+            filter_ehlo = 0;
+            filter_host = 0;
 
             /* Handle the DATA section via our AV checker */
             if(is_first_word(ctx->line, DATA_CMD, KL(DATA_CMD)))
@@ -757,6 +760,7 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
             {
                 messagex(ctx, LOG_DEBUG, "filtering EHLO response");
                 filter_ehlo = 1;
+                filter_host = 1;
 
                 /* A new message */
                 logline[0] = 0;
@@ -768,6 +772,8 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
              */
             else if(is_first_word(ctx->line, HELO_CMD, KL(HELO_CMD)))
             {
+                filter_host = 1;
+
                 /* A new message line */
                 logline[0] = 0;
             }
@@ -849,6 +855,26 @@ static int smtp_passthru(clamsmtp_context_t* ctx)
             }
 
             /*
+             * Certain mail servers (Postfix 1.x in particular) do a loop check
+             * on the 250 response after a EHLO or HELO. This is where we
+             * filter that to prevent loopback errors.
+             */
+            if(filter_host)
+            {
+                filter_host = 0;
+
+                if(check_first_word(ctx->line, OK_RSP, KL(OK_RSP), SMTP_DELIMS) > 0)
+                {
+                    messagex(ctx, LOG_DEBUG, "intercepting host response");
+
+                    if(write_data(ctx, &(ctx->client), SMTP_HELO_RSP) == -1)
+                        RETURN(-1);
+
+                    continue;
+                }
+            }
+
+            /*
              * Filter out any EHLO responses that we can't or don't want
              * to support. For example pipelining or TLS.
              */