Fix smtp response timeout

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index f9a14b678df39b82c4c1ab84a6624023b7ff4f65..d67daa873a4253e473142f5184b503a45763a787 100644 (file)
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -128,10 +128,16 @@ JH/26 The PIPE_CONNECT facility is promoted from experimental status and is now
       controlled by the build-time option SUPPORT_PIPE_CONNECT.
 
 PP/01 Unbreak heimdal_gssapi, broken in 4.92.
+
 JH/27 Bug 2404: Use the main-section configuration option "dsn_from" for
       success-DSN messages.  Previously the From: header was always the default
       one for these; the option was ignored.
 
+JH/28 Fix the timeout on smtp response to apply to the whole response.
+      Previously it was reset for every read, so a teergrubing peer sending
+      single bytes within the time limit could extend the connection for a
+      long time.  Credit to Qualsys Security Advisory Team for the discovery.
+
 
 Exim version 4.92
 -----------------

diff --git a/src/src/functions.h b/src/src/functions.h
index 33e296c13d62b2960265b326f30d0bd1e44652b0..7b5b00a2ded152ef00a9109ff044e9d116838fe6 100644 (file)
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -231,7 +231,7 @@ extern uschar *expand_string_copy(const uschar *);
 extern int_eximarith_t expand_string_integer(uschar *, BOOL);
 extern void    modify_variable(uschar *, void *);
 
-extern BOOL    fd_ready(int, int);
+extern BOOL    fd_ready(int, time_t);
 
 extern int     filter_interpret(uschar *, int, address_item **, uschar **);
 extern BOOL    filter_personal(string_item *, BOOL);
@@ -278,7 +278,7 @@ extern int     ip_connectedsocket(int, const uschar *, int, int,
                  int, host_item *, uschar **, const blob *);
 extern int     ip_get_address_family(int);
 extern void    ip_keepalive(int, const uschar *, BOOL);
-extern int     ip_recv(client_conn_ctx *, uschar *, int, int);
+extern int     ip_recv(client_conn_ctx *, uschar *, int, time_t);
 extern int     ip_socket(int, int);
 
 extern int     ip_tcpsocket(const uschar *, uschar **, int);

diff --git a/src/src/ip.c b/src/src/ip.c
index fb42f005107e442e92545b6bc806c1ec26024c3e..bf13d825c5ef52680cbf117cd38a6603967ffd3a 100644 (file)
--- a/src/src/ip.c
+++ b/src/src/ip.c
@@ -568,16 +568,15 @@ if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
 /*
 Arguments:
   fd          the file descriptor
-  timeout     the timeout, seconds
+  timelimit   the timeout endpoint, seconds-since-epoch
 Returns:      TRUE => ready for i/o
               FALSE => timed out, or other error
 */
 BOOL
-fd_ready(int fd, int timeout)
+fd_ready(int fd, time_t timelimit)
 {
 fd_set select_inset;
-time_t start_recv = time(NULL);
-int time_left = timeout;
+int time_left = timelimit - time(NULL);
 int rc;
 
 if (time_left <= 0)
@@ -611,8 +610,7 @@ do
     DEBUG(D_transport) debug_printf("EINTR while waiting for socket data\n");
 
     /* Watch out, 'continue' jumps to the condition, not to the loops top */
-    time_left = timeout - (time(NULL) - start_recv);
-    if (time_left > 0) continue;
+    if ((time_left = timelimit - time(NULL)) > 0) continue;
     }
 
   if (rc <= 0)
@@ -636,18 +634,18 @@ Arguments:
   cctx        the connection context (socket fd, possibly TLS context)
   buffer      to read into
   bufsize     the buffer size
-  timeout     the timeout
+  timelimit   the timeout endpoint, seconds-since-epoch
 
 Returns:      > 0 => that much data read
               <= 0 on error or EOF; errno set - zero for EOF
 */
 
 int
-ip_recv(client_conn_ctx * cctx, uschar * buffer, int buffsize, int timeout)
+ip_recv(client_conn_ctx * cctx, uschar * buffer, int buffsize, time_t timelimit)
 {
 int rc;
 
-if (!fd_ready(cctx->sock, timeout))
+if (!fd_ready(cctx->sock, timelimit))
   return -1;
 
 /* The socket is ready, read from it (via TLS if it's active). On EOF (i.e.

diff --git a/src/src/malware.c b/src/src/malware.c
index 2e783e398eb9784ae58caddf4c0708a6a9804077..91649cf2022d0d51089e652fceb4a993be35431b 100644 (file)
--- a/src/src/malware.c
+++ b/src/src/malware.c
@@ -349,13 +349,13 @@ return cre;
          -2 on timeout or error
 */
 static int
-recv_line(int fd, uschar * buffer, int bsize, int tmo)
+recv_line(int fd, uschar * buffer, int bsize, time_t tmo)
 {
 uschar * p = buffer;
 ssize_t rcv;
 BOOL ok = FALSE;
 
-if (!fd_ready(fd, tmo-time(NULL)))
+if (!fd_ready(fd, tmo))
   return -2;
 
 /*XXX tmo handling assumes we always get a whole line */
@@ -382,9 +382,9 @@ return p - buffer;
 
 /* return TRUE iff size as requested */
 static BOOL
-recv_len(int sock, void * buf, int size, int tmo)
+recv_len(int sock, void * buf, int size, time_t tmo)
 {
-return fd_ready(sock, tmo-time(NULL))
+return fd_ready(sock, tmo)
   ? recv(sock, buf, size, 0) == size
   : FALSE;
 }
@@ -430,7 +430,7 @@ for (;;)
 }
 
 static inline int
-mksd_read_lines (int sock, uschar *av_buffer, int av_buffer_size, int tmo)
+mksd_read_lines (int sock, uschar *av_buffer, int av_buffer_size, time_t tmo)
 {
 client_conn_ctx cctx = {.sock = sock};
 int offset = 0;
@@ -438,7 +438,7 @@ int i;
 
 do
   {
-  i = ip_recv(&cctx, av_buffer+offset, av_buffer_size-offset, tmo-time(NULL));
+  i = ip_recv(&cctx, av_buffer+offset, av_buffer_size-offset, tmo);
   if (i <= 0)
     {
     (void) malware_panic_defer(US"unable to read from mksd UNIX socket (/var/run/mksd/socket)");
@@ -497,7 +497,7 @@ switch (*line)
 
 static int
 mksd_scan_packed(struct scan * scanent, int sock, const uschar * scan_filename,
-  int tmo)
+  time_t tmo)
 {
 struct iovec iov[3];
 const char *cmd = "MSQ\n";
@@ -746,7 +746,7 @@ if (!malware_ok)
       if (m_sock_send(malware_daemon_ctx.sock, scanrequest, Ustrlen(scanrequest), &errstr) < 0)
         return m_panic_defer(scanent, CUS callout_address, errstr);
 
-      bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo-time(NULL));
+      bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo);
 
       if (bread <= 0)
         return m_panic_defer_3(scanent, CUS callout_address,
@@ -1063,7 +1063,7 @@ badseek:  err = errno;
        if (m_sock_send(malware_daemon_ctx.sock, cmdopt[i], Ustrlen(cmdopt[i]), &errstr) < 0)
          return m_panic_defer(scanent, CUS callout_address, errstr);
 
-       bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo-time(NULL));
+       bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo);
        if (bread > 0) av_buffer[bread]='\0';
        if (bread < 0)
          return m_panic_defer_3(scanent, CUS callout_address,
@@ -1095,7 +1095,7 @@ badseek:  err = errno;
          {
          errno = ETIMEDOUT;
          i =  av_buffer+sizeof(av_buffer)-p;
-         if ((bread= ip_recv(&malware_daemon_ctx, p, i-1, tmo-time(NULL))) < 0)
+         if ((bread= ip_recv(&malware_daemon_ctx, p, i-1, tmo)) < 0)
            return m_panic_defer_3(scanent, CUS callout_address,
              string_sprintf("unable to read result (%s)", strerror(errno)),
              malware_daemon_ctx.sock);
@@ -1400,7 +1400,7 @@ badseek:  err = errno;
 
       /* wait for result */
       memset(av_buffer, 0, sizeof(av_buffer));
-      if ((bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo-time(NULL))) <= 0)
+      if ((bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo)) <= 0)
        return m_panic_defer_3(scanent, CUS callout_address,
          string_sprintf("unable to read from UNIX socket (%s)", scanner_options),
          malware_daemon_ctx.sock);
@@ -1736,7 +1736,7 @@ b_seek:   err = errno;
 
       /* Read the result */
       memset(av_buffer, 0, sizeof(av_buffer));
-      bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo-time(NULL));
+      bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo);
       (void)close(malware_daemon_ctx.sock);
       malware_daemon_ctx.sock = -1;
       malware_daemon_ctx.tls_ctx = NULL;
@@ -1894,7 +1894,7 @@ b_seek:   err = errno;
        return m_panic_defer(scanent, CUS callout_address, errstr);
 
       /* Read the result */
-      bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo-time(NULL));
+      bread = ip_recv(&malware_daemon_ctx, av_buffer, sizeof(av_buffer), tmo);
 
       if (bread <= 0)
        return m_panic_defer_3(scanent, CUS callout_address,

diff --git a/src/src/routers/iplookup.c b/src/src/routers/iplookup.c
index ff67af38dd8b512832ee8c1aca559829533e3379..13849f9f1e48370a7b3a548f0ad5595f809a86f2 100644 (file)
--- a/src/src/routers/iplookup.c
+++ b/src/src/routers/iplookup.c
@@ -279,7 +279,7 @@ while ((hostname = string_nextinlist(&listptr, &sep, host_buffer,
     /* Read the response and close the socket. If the read fails, try the
     next IP address. */
 
-    count = ip_recv(&query_cctx, reply, sizeof(reply) - 1, ob->timeout);
+    count = ip_recv(&query_cctx, reply, sizeof(reply) - 1, time(NULL) + ob->timeout);
     (void)close(query_cctx.sock);
     if (count <= 0)
       {

diff --git a/src/src/smtp_out.c b/src/src/smtp_out.c
index c1cf901dc9f3d174de4d2139e870eb349115a645..c19d12d43599c5baa5d94ffb9ede2a762ceed0cc 100644 (file)
--- a/src/src/smtp_out.c
+++ b/src/src/smtp_out.c
@@ -589,14 +589,14 @@ Arguments:
   inblock   the SMTP input block (contains holding buffer, socket, etc.)
   buffer    where to put the line
   size      space available for the line
-  timeout   the timeout to use when reading a packet
+  timelimit deadline for reading the lime, seconds past epoch
 
 Returns:    length of a line that has been put in the buffer
             -1 otherwise, with errno set
 */
 
 static int
-read_response_line(smtp_inblock *inblock, uschar *buffer, int size, int timeout)
+read_response_line(smtp_inblock *inblock, uschar *buffer, int size, time_t timelimit)
 {
 uschar *p = buffer;
 uschar *ptr = inblock->ptr;
@@ -639,7 +639,7 @@ for (;;)
 
   /* Need to read a new input packet. */
 
-  if((rc = ip_recv(cctx, inblock->buffer, inblock->buffersize, timeout)) <= 0)
+  if((rc = ip_recv(cctx, inblock->buffer, inblock->buffersize, timelimit)) <= 0)
     {
     DEBUG(D_deliver|D_transport|D_acl|D_v)
       debug_printf_indent(errno ? "  SMTP(%s)<<\n" : "  SMTP(closed)<<\n",
@@ -696,6 +696,7 @@ smtp_read_response(void * sx0, uschar * buffer, int size, int okdigit,
 smtp_context * sx = sx0;
 uschar * ptr = buffer;
 int count = 0;
+time_t timelimit = time(NULL) + timeout;
 
 errno = 0;  /* Ensure errno starts out zero */
 
@@ -718,7 +719,7 @@ response. */
 
 for (;;)
   {
-  if ((count = read_response_line(&sx->inblock, ptr, size, timeout)) < 0)
+  if ((count = read_response_line(&sx->inblock, ptr, size, timelimit)) < 0)
     return FALSE;
 
   HDEBUG(D_transport|D_acl|D_v)

diff --git a/src/src/spam.c b/src/src/spam.c
index 3ffc514f09cf13432f38beedc442929dfe9c3dcc..7e334852e53ba4454a50d0bee545112423deb12c 100644 (file)
--- a/src/src/spam.c
+++ b/src/src/spam.c
@@ -503,7 +503,7 @@ offset = 0;
 while ((i = ip_recv(&spamd_cctx,
                   spamd_buffer + offset,
                   sizeof(spamd_buffer) - offset - 1,
-                  sd->timeout - time(NULL) + start)) > 0)
+                  sd->timeout + start)) > 0)
   offset += i;
 spamd_buffer[offset] = '\0';   /* guard byte */
 

diff --git a/src/src/transports/smtp_socks.c b/src/src/transports/smtp_socks.c
index 09273c747485c72c57e33ebf8f7f723cd89c6bd2..41dc781473236fa489e1dbf2732b0d5a61addaf6 100644 (file)
--- a/src/src/transports/smtp_socks.c
+++ b/src/src/transports/smtp_socks.c
@@ -128,7 +128,7 @@ switch(method)
 #ifdef TCP_QUICKACK
     (void) setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
 #endif
-    if (!fd_ready(fd, tmo-time(NULL)) || read(fd, s, 2) != 2)
+    if (!fd_ready(fd, tmo) || read(fd, s, 2) != 2)
       return FAIL;
     HDEBUG(D_transport|D_acl|D_v)
       debug_printf_indent("  SOCKS<< %02x %02x\n", s[0], s[1]);
@@ -319,7 +319,7 @@ HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  SOCKS>> 05 01 %02x\n", sob-
 (void) setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
 #endif
 
-if (  !fd_ready(fd, tmo-time(NULL))
+if (  !fd_ready(fd, tmo)
    || read(fd, buf, 2) != 2
    )
   goto rcv_err;
@@ -368,7 +368,7 @@ if (send(fd, buf, size, 0) < 0)
 /* expect conn-reply (success, local(ipver, addr, port))
 of same length as conn-request, or non-success fail code */
 
-if (  !fd_ready(fd, tmo-time(NULL))
+if (  !fd_ready(fd, tmo)
    || (size = read(fd, buf, size)) < 2
    )
   goto rcv_err;

diff --git a/src/src/verify.c b/src/src/verify.c
index 7125a6da1a309a3fe434a89d31f182fa6cfee760..5026a417cea16d28753b367efc74b22f503d9da4 100644 (file)
--- a/src/src/verify.c
+++ b/src/src/verify.c
@@ -2745,7 +2745,7 @@ for (;;)
   int size = sizeof(buffer) - (p - buffer);
 
   if (size <= 0) goto END_OFF;   /* Buffer filled without seeing \n. */
-  count = ip_recv(&ident_conn_ctx, p, size, rfc1413_query_timeout);
+  count = ip_recv(&ident_conn_ctx, p, size, time(NULL) + rfc1413_query_timeout);
   if (count <= 0) goto END_OFF;  /* Read error or EOF */
 
   /* Scan what we just read, to see if we have reached the terminating \r\n. Be