rtpdec: Read the packet length for all RTCP packet types
authorJohn Brooks <john.brooks@bluecherry.net>
Wed, 12 Oct 2011 06:53:12 +0000 (00:53 -0600)
committerMichael Niedermayer <michaelni@gmx.at>
Fri, 4 Nov 2011 00:09:05 +0000 (01:09 +0100)
This allows skipping past unsupported RTCP packet types, as
RFC 3550 section 6.1 mandates.

Currently this only has any practical effect if a sender puts
an unrecognized type before RTCP_BYE in a compounded packet, or
(incorrectly) does not put RTCP_SR first.

Signed-off-by: Martin Storsjö <martin@martin.st>
(cherry picked from commit 07b77fe3871f86b87e35876d38f1969da5ece4b2)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
libavformat/rtpdec.c

index bc0aea6..130a78d 100644 (file)
@@ -111,14 +111,15 @@ RTPDynamicProtocolHandler *ff_rtp_handler_find_by_id(int id,
 static int rtcp_parse_packet(RTPDemuxContext *s, const unsigned char *buf, int len)
 {
     int payload_len;
-    while (len >= 2) {
+    while (len >= 4) {
+        payload_len = FFMIN(len, (AV_RB16(buf + 2) + 1) * 4);
+
         switch (buf[1]) {
         case RTCP_SR:
-            if (len < 20) {
+            if (payload_len < 20) {
                 av_log(NULL, AV_LOG_ERROR, "Invalid length for RTCP SR packet\n");
                 return AVERROR_INVALIDDATA;
             }
-            payload_len = (AV_RB16(buf + 2) + 1) * 4;
 
             s->last_rtcp_ntp_time = AV_RB64(buf + 8);
             s->last_rtcp_timestamp = AV_RB32(buf + 16);
@@ -129,14 +130,13 @@ static int rtcp_parse_packet(RTPDemuxContext *s, const unsigned char *buf, int l
                 s->rtcp_ts_offset = s->last_rtcp_timestamp - s->base_timestamp;
             }
 
-            buf += payload_len;
-            len -= payload_len;
             break;
         case RTCP_BYE:
             return -RTCP_BYE;
-        default:
-            return -1;
         }
+
+        buf += payload_len;
+        len -= payload_len;
     }
     return -1;
 }