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@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2018-11-09 03:12:45 +01:00
parent 3504004879
commit 1f99674ddd

View File

@ -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 */