[FFmpeg-devel,12/12] avcodec/4xm: Check index in decode_i_block() also in the path where its not used.

Submitted by Michael Niedermayer on Sept. 25, 2019, 8:38 p.m.

Details

Message ID 20190925203858.27870-12-michael@niedermayer.cc
State New
Headers show

Commit Message

Michael Niedermayer Sept. 25, 2019, 8:38 p.m.
Fixes: Infinite loop
Fixes: signed integer overflow: 2147483644 + 16 cannot be represented in type 'int'
Fixes: 16169/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5662570416963584
Fixes: 16782/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5743163859271680
Fixes: 17641/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5711603562971136

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

Comments

Paul B Mahol Sept. 26, 2019, 8:07 a.m.
lgtm

On 9/25/19, Michael Niedermayer <michael@niedermayer.cc> wrote:
> Fixes: Infinite loop
> Fixes: signed integer overflow: 2147483644 + 16 cannot be represented in
> type 'int'
> Fixes:
> 16169/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5662570416963584
> Fixes:
> 16782/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5743163859271680
> Fixes:
> 17641/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5711603562971136
>
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/4xm.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
> index 1f4e2aee24..336c651d31 100644
> --- a/libavcodec/4xm.c
> +++ b/libavcodec/4xm.c
> @@ -525,6 +525,10 @@ static int decode_i_block(FourXContext *f, int16_t
> *block)
>              break;
>          if (code == 0xf0) {
>              i += 16;
> +            if (i >= 64) {
> +                av_log(f->avctx, AV_LOG_ERROR, "run %d overflow\n", i);
> +                return 0;
> +            }
>          } else {
>              if (code & 0xf) {
>                  level = get_xbits(&f->gb, code & 0xf);
> --
> 2.23.0
>
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Michael Niedermayer Sept. 26, 2019, 6:39 p.m.
On Thu, Sep 26, 2019 at 10:07:29AM +0200, Paul B Mahol wrote:
> lgtm

will apply

thx

[...]

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diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index 1f4e2aee24..336c651d31 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -525,6 +525,10 @@  static int decode_i_block(FourXContext *f, int16_t *block)
             break;
         if (code == 0xf0) {
             i += 16;
+            if (i >= 64) {
+                av_log(f->avctx, AV_LOG_ERROR, "run %d overflow\n", i);
+                return 0;
+            }
         } else {
             if (code & 0xf) {
                 level = get_xbits(&f->gb, code & 0xf);