ffmpeg | branch: master | Michael Niedermayer <michael@niedermayer.cc> | Sat Oct 26 23:58:02 2019 +0200| [069be4aa5ddce4479b18896d80a852b144e680df] | committer: Michael Niedermayer avcodec/libvorbisdec: Fix insufficient input checks leading to out of array reads Fixes: 16144/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_LIBVORBIS_fuzzer-5638618940440576 Fixes: out of array read Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=069be4aa5ddce4479b...

libavcodec/libvorbisdec.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/libavcodec/libvorbisdec.c b/libavcodec/libvorbisdec.c index 89cbbb41b6..3c53b8fdaf 100644 --- a/libavcodec/libvorbisdec.c +++ b/libavcodec/libvorbisdec.c @@ -64,22 +64,25 @@ static int oggvorbis_decode_init(AVCodecContext *avccontext) { } } else if(*p == 2) { unsigned int offset = 1; + unsigned int sizesum = 1; p++; for(i=0; i<2; i++) { hsizes[i] = 0; - while((*p == 0xFF) && (offset < avccontext->extradata_size)) { + while((*p == 0xFF) && (sizesum < avccontext->extradata_size)) { hsizes[i] += 0xFF; offset++; + sizesum += 1 + 0xFF; p++; } - if(offset >= avccontext->extradata_size - 1) { + hsizes[i] += *p; + offset++; + sizesum += 1 + *p; + if(sizesum > avccontext->extradata_size) { av_log(avccontext, AV_LOG_ERROR, "vorbis header sizes damaged\n"); ret = AVERROR_INVALIDDATA; goto error; } - hsizes[i] += *p; - offset++; p++; } hsizes[2] = avccontext->extradata_size - hsizes[0]-hsizes[1]-offset;