[FFmpeg-cvslog] avcodec/pngdec: Check compression method

[Michael Niedermayer]

ffmpeg | branch: release/4.1 | Michael Niedermayer <michael at niedermayer.cc> | Fri Nov  9 03:12:45 2018 +0100| [89d65915cf6e7d79bd57896a4eb3fd626e699fc1] | committer: Michael Niedermayer

avcodec/pngdec: Check compression method

method 0 (inflate/deflate) is the only specified in the specification and the only supported

Fixes: Timeout
Fixes: 10976/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PNG_fuzzer-5729372588736512

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 1f99674ddddcc33f4c37def0a206e31ad7c4c1af)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=89d65915cf6e7d79bd57896a4eb3fd626e699fc1
---

 libavcodec/pngdec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 01144680f2..189bb9a4c1 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -578,6 +578,10 @@ static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
     }
     s->color_type       = bytestream2_get_byte(&s->gb);
     s->compression_type = bytestream2_get_byte(&s->gb);
+    if (s->compression_type) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid compression method %d\n", s->compression_type);
+        goto error;
+    }
     s->filter_type      = bytestream2_get_byte(&s->gb);
     s->interlace_type   = bytestream2_get_byte(&s->gb);
     bytestream2_skip(&s->gb, 4); /* crc */