avcodec/atrac9dec: Clamp band_ext_data to max that can be read if skipped.

Fixes: out of array read
Fixes: 19327/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ATRAC9_fuzzer-5679823087468544

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-12-17 00:19:42 +01:00
parent 1f20969457
commit 18ff210efb

View File

@ -223,8 +223,18 @@ static inline int parse_band_ext(ATRAC9Context *s, ATRAC9BlockData *b,
b->channel[0].band_ext = get_bits(gb, 2);
b->channel[0].band_ext = ext_band > 2 ? b->channel[0].band_ext : 4;
if (!get_bits(gb, 5))
if (!get_bits(gb, 5)) {
for (int i = 0; i <= stereo; i++) {
ATRAC9ChannelData *c = &b->channel[i];
const int count = at9_tab_band_ext_cnt[c->band_ext][ext_band];
for (int j = 0; j < count; j++) {
int len = at9_tab_band_ext_lengths[c->band_ext][ext_band][j];
c->band_ext_data[j] = av_clip_uintp2_c(c->band_ext_data[j], len);
}
}
return 0;
}
for (int i = 0; i <= stereo; i++) {
ATRAC9ChannelData *c = &b->channel[i];