diff mbox

[FFmpeg-devel,1/2] avcodec/mpeg4videodec: Check idx in mpeg4_decode_studio_block()

Message ID 20190310004100.3811-1-michael@niedermayer.cc
State Accepted
Commit d227ed5d598340e719eff7156b1aa0a4469e9a6a
Headers show

Commit Message

Michael Niedermayer March 10, 2019, 12:40 a.m. UTC 
Fixes: Out of array access
Fixes: 13500/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_fuzzer-5769760178962432

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/mpeg4videodec.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Kieran Kunhya March 11, 2019, 6:39 a.m. UTC | #1 
On Sun, 10 Mar 2019 at 04:43 Michael Niedermayer <michael@niedermayer.cc>
wrote:

> Fixes: Out of array access
> Fixes:
> 13500/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_fuzzer-5769760178962432
>
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by
> <https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by>:
> Michael Niedermayer <michael@niedermayer.cc>
>

Ok.

Kieran
Michael Niedermayer March 11, 2019, 7:59 p.m. UTC | #2 
On Mon, Mar 11, 2019 at 10:39:20AM +0400, Kieran Kunhya wrote:
> On Sun, 10 Mar 2019 at 04:43 Michael Niedermayer <michael@niedermayer.cc>
> wrote:
> 
> > Fixes: Out of array access
> > Fixes:
> > 13500/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_fuzzer-5769760178962432
> >
> > Found-by: continuous fuzzing process
> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by
> > <https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by>:
> > Michael Niedermayer <michael@niedermayer.cc>
> >
> 
> Ok.

will apply 

thx

[...]
diff mbox

Patch

diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index ecd028a87c..bb9f1e3f2c 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -1899,14 +1899,20 @@  static int mpeg4_decode_studio_block(MpegEncContext *s, int32_t block[64], int n
             code >>= 1;
             run = (1 << (additional_code_len - 1)) + code;
             idx += run;
+            if (idx > 63)
+                return AVERROR_INVALIDDATA;
             j = scantable[idx++];
             block[j] = sign ? 1 : -1;
         } else if (group >= 13 && group <= 20) {
             /* Level value (Table B.49) */
+            if (idx > 63)
+                return AVERROR_INVALIDDATA;
             j = scantable[idx++];
             block[j] = get_xbits(&s->gb, additional_code_len);
         } else if (group == 21) {
             /* Escape */
+            if (idx > 63)
+                return AVERROR_INVALIDDATA;
             j = scantable[idx++];
             additional_code_len = s->avctx->bits_per_raw_sample + s->dct_precision + 4;
             flc = get_bits(&s->gb, additional_code_len);