[SCM] libav/experimental: Check 4xm headers for validity. This should avoid 1/0.

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 8bb7d97be0cda3c944956c79c50d0cf6f1efb7b9
Author: Michael Niedermayer <michaelni at gmx.at>
Date:   Sun Jan 16 18:22:29 2011 +0000

    Check 4xm headers for validity. This should avoid 1/0.
    
    Originally committed as revision 26392 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavformat/4xm.c b/libavformat/4xm.c
index a697f8d..dfbf032 100644
--- a/libavformat/4xm.c
+++ b/libavformat/4xm.c
@@ -185,6 +185,13 @@ static int fourxm_read_header(AVFormatContext *s,
             fourxm->tracks[current_track].sample_rate = AV_RL32(&header[i + 40]);
             fourxm->tracks[current_track].bits        = AV_RL32(&header[i + 44]);
             fourxm->tracks[current_track].audio_pts   = 0;
+            if(   fourxm->tracks[current_track].channels    <= 0
+               || fourxm->tracks[current_track].sample_rate <= 0
+               || fourxm->tracks[current_track].bits        <  0){
+                av_log(s, AV_LOG_ERROR, "audio header invalid\n");
+                ret= -1;
+                goto fail;
+            }
             i += 8 + size;
 
             /* allocate a new AVStream */
@@ -291,7 +298,7 @@ static int fourxm_read_packet(AVFormatContext *s,
             out_size= get_le32(pb);
             size-=8;
 
-            if (track_number < fourxm->track_count) {
+            if (track_number < fourxm->track_count && fourxm->tracks[track_number].channels>0) {
                 ret= av_get_packet(s->pb, pkt, size);
                 if(ret<0)
                     return AVERROR(EIO);

-- 
Libav/FFmpeg packaging