[FFmpeg-devel,1/4] avcodec/atrac3plus: Check split point in fill mode 3

Submitted by Michael Niedermayer on Oct. 23, 2019, 6:57 p.m.

Details

Message ID 20191023185714.2412-1-michael@niedermayer.cc
State Accepted
Commit de5102fd92de8d353fdf060375ed3ce859c83977
Headers show

Commit Message

Michael Niedermayer Oct. 23, 2019, 6:57 p.m.
Fixes: index 32 out of bounds for type 'int [32]'
Fixes: 18350/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ATRAC3P_fuzzer-5643794862571520

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/atrac3plus.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Michael Niedermayer Nov. 9, 2019, 4:56 p.m.
On Wed, Oct 23, 2019 at 08:57:11PM +0200, Michael Niedermayer wrote:
> Fixes: index 32 out of bounds for type 'int [32]'
> Fixes: 18350/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ATRAC3P_fuzzer-5643794862571520
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/atrac3plus.c | 4 ++++
>  1 file changed, 4 insertions(+)

will apply

[...]

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diff --git a/libavcodec/atrac3plus.c b/libavcodec/atrac3plus.c
index 9f964efb4d..8d17889582 100644
--- a/libavcodec/atrac3plus.c
+++ b/libavcodec/atrac3plus.c
@@ -456,6 +456,10 @@  static int decode_channel_wordlen(GetBitContext *gb, Atrac3pChanUnitCtx *ctx,
     } else if (chan->fill_mode == 3) {
         pos = ch_num ? chan->num_coded_vals + chan->split_point
                      : ctx->num_quant_units - chan->split_point;
+        if (pos > FF_ARRAY_ELEMS(chan->qu_wordlen)) {
+            av_log(avctx, AV_LOG_ERROR, "Split point beyond array\n");
+            pos = FF_ARRAY_ELEMS(chan->qu_wordlen);
+        }
         for (i = chan->num_coded_vals; i < pos; i++)
             chan->qu_wordlen[i] = 1;
     }