@@ -789,14 +789,20 @@ static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
// read first value and residuals in case of a random access block
if (bd->ra_block) {
+ start = FFMIN(opt_order, 3);
+ av_assert0(sb_length <= sconf->frame_length);
+ if (sb_length <= start) {
+ // opt_order or sb_length may be corrupted, either way this is unsupported and not well defined in the specification
+ av_log(avctx, AV_LOG_ERROR, "Sub block length smaller or equal start\n");
+ return AVERROR_PATCHWELCOME;
+ }
+
if (opt_order)
bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
if (opt_order > 1)
bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));
if (opt_order > 2)
bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));
-
- start = FFMIN(opt_order, 3);
}
// read all residuals
Fixes: out of array access Fixes: 15277/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5184853437317120 Fixes: 15280/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5741062137577472 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/alsdec.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)