From 18ff210efb8d158f3e8c79508d99a52eaebf9d48 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 17 Dec 2019 00:19:42 +0100 Subject: [PATCH] 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 Signed-off-by: Michael Niedermayer --- libavcodec/atrac9dec.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/libavcodec/atrac9dec.c b/libavcodec/atrac9dec.c index 5415d1348e..075d610e75 100644 --- a/libavcodec/atrac9dec.c +++ b/libavcodec/atrac9dec.c @@ -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];