avcodec/flac_parser: Do not lose header count in find_headers_search()

Fixes: Timeout
Fixes: out of array access
Fixes: 20274/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FLAC_fuzzer-5649631988154368
Fixes: 19275/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FLAC_fuzzer-5757535722405888

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 2020-02-03 23:20:23 +01:00
parent abb5762e98
commit 55f9683cf6

View File

@ -208,16 +208,20 @@ static int find_headers_search(FLACParseContext *fpc, uint8_t *buf,
uint32_t x;
for (i = 0; i < mod_offset; i++) {
if ((AV_RB16(buf + i) & 0xFFFE) == 0xFFF8)
size = find_headers_search_validate(fpc, search_start + i);
if ((AV_RB16(buf + i) & 0xFFFE) == 0xFFF8) {
int ret = find_headers_search_validate(fpc, search_start + i);
size = FFMAX(size, ret);
}
}
for (; i < buf_size - 1; i += 4) {
x = AV_RN32(buf + i);
if (((x & ~(x + 0x01010101)) & 0x80808080)) {
for (j = 0; j < 4; j++) {
if ((AV_RB16(buf + i + j) & 0xFFFE) == 0xFFF8)
size = find_headers_search_validate(fpc, search_start + i + j);
if ((AV_RB16(buf + i + j) & 0xFFFE) == 0xFFF8) {
int ret = find_headers_search_validate(fpc, search_start + i + j);
size = FFMAX(size, ret);
}
}
}
}