avformat/avidec: Check for dv streams before using priv_data in parse ##dc/##wb

Fixes: null pointer dereference
Fixes: 31588/clusterfuzz-testcase-minimized-ffmpeg_dem_AVI_fuzzer-6165716135968768

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit f733688d30)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2021-03-18 10:59:19 +01:00
parent 4197e4144b
commit d75ae8f6a7

View File

@ -1257,7 +1257,7 @@ start_sync:
AVStream *st1 = s->streams[1];
AVIStream *ast1 = st1->priv_data;
// workaround for broken small-file-bug402.avi
if ( d[2] == 'w' && d[3] == 'b'
if (ast1 && d[2] == 'w' && d[3] == 'b'
&& n == 0
&& st ->codecpar->codec_type == AVMEDIA_TYPE_VIDEO
&& st1->codecpar->codec_type == AVMEDIA_TYPE_AUDIO