Merged revisions 324237 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

........
  r324237 | twilson | 2011-06-20 12:33:07 -0500 (Mon, 20 Jun 2011) | 12 lines
  
  Ignore media offers with a port of 0
  
  Section 5.1 of RFC3264 states:
    A port number of zero in the offer indicates that the stream is offered
    but MUST NOT be used.
  
  (closes issue ASTERISK-17845)
  Reported by: jacco
  Patches: 
        issue19281_2.patch uploaded by jacco (license 1277)
  Tested by: jacco, twilson
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@324238 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -8789,8 +8789,8 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 		nextm = get_sdp_iterate(&next, req, "m");
 
 		/* Search for audio media definition */
-		if ((sscanf(m, "audio %30u/%30u RTP/%4s %n", &x, &numberofports, protocol, &len) == 3 && len > 0) ||
-		    (sscanf(m, "audio %30u RTP/%4s %n", &x, protocol, &len) == 2 && len > 0)) {
+		if ((sscanf(m, "audio %30u/%30u RTP/%4s %n", &x, &numberofports, protocol, &len) == 3 && len > 0 && x) ||
+		    (sscanf(m, "audio %30u RTP/%4s %n", &x, protocol, &len) == 2 && len > 0 && x)) {
 			if (!strcmp(protocol, "SAVP")) {
 				secure_audio = 1;
 			} else if (strcmp(protocol, "AVP")) {
@@ -8817,8 +8817,8 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 				ast_rtp_codecs_payloads_set_m_type(&newaudiortp, NULL, codec);
 			}
 		/* Search for video media definition */
-		} else if ((sscanf(m, "video %30u/%30u RTP/%4s %n", &x, &numberofports, protocol, &len) == 3 && len > 0) ||
-			   (sscanf(m, "video %30u RTP/%4s %n", &x, protocol, &len) == 2 && len >= 0)) {
+		} else if ((sscanf(m, "video %30u/%30u RTP/%4s %n", &x, &numberofports, protocol, &len) == 3 && len > 0 && x) ||
+			   (sscanf(m, "video %30u RTP/%4s %n", &x, protocol, &len) == 2 && len >= 0 && x)) {
 			if (!strcmp(protocol, "SAVP")) {
 				secure_video = 1;
 			} else if (strcmp(protocol, "AVP")) {
@@ -8845,8 +8845,8 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 				ast_rtp_codecs_payloads_set_m_type(&newvideortp, NULL, codec);
 			}
 		/* Search for text media definition */
-		} else if ((sscanf(m, "text %30u/%30u RTP/AVP %n", &x, &numberofports, &len) == 2 && len > 0) ||
-			   (sscanf(m, "text %30u RTP/AVP %n", &x, &len) == 1 && len > 0)) {
+		} else if ((sscanf(m, "text %30u/%30u RTP/AVP %n", &x, &numberofports, &len) == 2 && len > 0 && x) ||
+			   (sscanf(m, "text %30u RTP/AVP %n", &x, &len) == 1 && len > 0 && x)) {
 			text = TRUE;
 			p->notext = FALSE;
 			p->offered_media[SDP_TEXT].offered = TRUE;
@@ -8867,8 +8867,8 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 				ast_rtp_codecs_payloads_set_m_type(&newtextrtp, NULL, codec);
 			}
 		/* Search for image media definition */
-		} else if (p->udptl && ((sscanf(m, "image %30u udptl t38%n", &x, &len) == 1 && len > 0) ||
-					(sscanf(m, "image %30u UDPTL t38%n", &x, &len) == 1 && len > 0) )) {
+		} else if (p->udptl && ((sscanf(m, "image %30u udptl t38%n", &x, &len) == 1 && len > 0 && x) ||
+					(sscanf(m, "image %30u UDPTL t38%n", &x, &len) == 1 && len > 0 && x) )) {
 			image = TRUE;
 			if (debug)
 				ast_verbose("Got T.38 offer in SDP in dialog %s\n", p->callid);