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avcodec/libvorbisdec: Fix insufficient input checks leading to out of array reads

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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>
This commit is contained in:
Michael Niedermayer 2019-10-26 23:58:02 +02:00
parent 1850c3feaa
commit 069be4aa5d
1 changed files with 7 additions and 4 deletions
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11
libavcodec/libvorbisdec.c
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@ -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;