[FFmpeg-cvslog] avformat/matroskadec: Fix infinite loop with bz decompression

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Thu Feb  3 22:46:55 2022 +0100| [94fc589f8e59680a99fa62df025d1473ecf03b2d] | committer: Michael Niedermayer

avformat/matroskadec: Fix infinite loop with bz decompression

The same check is added to zlib too, it seems not needed there though

Fixes: Infinite loop
Fixes: 43932/clusterfuzz-testcase-minimized-ffmpeg_dem_MATROSKA_fuzzer-6175167573786624

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 9c3d2cbb510674226b0c8fa6b146bf891f83786c)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=94fc589f8e59680a99fa62df025d1473ecf03b2d
---

 libavformat/matroskadec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index e316dbd0a2..60f2e767a6 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -1633,7 +1633,7 @@ static int matroska_decode_buffer(uint8_t **buf, int *buf_size,
     case MATROSKA_TRACK_ENCODING_COMP_ZLIB:
     {
         z_stream zstream = { 0 };
-        if (inflateInit(&zstream) != Z_OK)
+        if (!pkt_size || inflateInit(&zstream) != Z_OK)
             return -1;
         zstream.next_in  = data;
         zstream.avail_in = isize;
@@ -1666,7 +1666,7 @@ static int matroska_decode_buffer(uint8_t **buf, int *buf_size,
     case MATROSKA_TRACK_ENCODING_COMP_BZLIB:
     {
         bz_stream bzstream = { 0 };
-        if (BZ2_bzDecompressInit(&bzstream, 0, 0) != BZ_OK)
+        if (!pkt_size || BZ2_bzDecompressInit(&bzstream, 0, 0) != BZ_OK)
             return -1;
         bzstream.next_in  = data;
         bzstream.avail_in = isize;