On Thu, Jul 21, 2022 at 12:17:22AM +0200, Andreas Rheinhardt wrote: > Michael Niedermayer: > > On Tue, Jul 19, 2022 at 08:37:38AM -0300, James Almer wrote: > >> > >> > >> On 7/19/2022 8:34 AM, Michael Niedermayer wrote: > >>> Fixes: Timeout > >>> Fixes: > >>> 49160/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FFV1_fuzzer-5672826144686080 > >>> > >>> Found-by: continuous fuzzing process > >>> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > >>> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > >>> --- > >>> libavcodec/ffv1dec.c | 6 +++++- > >>> 1 file changed, 5 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/libavcodec/ffv1dec.c b/libavcodec/ffv1dec.c > >>> index 01ddcaa512..9bdac0be4e 100644 > >>> --- a/libavcodec/ffv1dec.c > >>> +++ b/libavcodec/ffv1dec.c > >>> @@ -883,7 +883,11 @@ static int decode_frame(AVCodecContext *avctx, > >>> AVFrame *rframe, > >>> if (buf_size < avctx->width * avctx->height / (128*8)) > >>> return AVERROR_INVALIDDATA; > >>> } else { > >>> - if (buf_size < avctx->height / 8) > >>> + int i; > >> > >> for (int i... > > > > will apply with that change > > > > thx > > > > James' suggestion made you use an uninitialized i in the actual check;
yes
> and even the original check is wrong, as one can overrun ff_log2_run
> (unless there is a check that I am not missing).
Theres a check but its too late
> So it seems to me that
> reverting 15785e044ee1265464bb4f3ed727e2a8074f97b4 is appropriate.
not against that but heres a quick fix attempt
Author: Michael Niedermayer <mich...@niedermayer.cc>
Date: Thu Jul 21 00:20:41 2022 +0200
avcodec/ffv1dec: Fix AC_GOLOMB_RICE min size check
Found-by: mkver
Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
diff --git a/libavcodec/ffv1dec.c b/libavcodec/ffv1dec.c
index d71584505d..c6eca3227c 100644
--- a/libavcodec/ffv1dec.c
+++ b/libavcodec/ffv1dec.c
@@ -884,9 +884,14 @@ static int decode_frame(AVCodecContext *avctx, AVFrame
*rframe,
return AVERROR_INVALIDDATA;
} else {
int w = avctx->width;
- for (int i = 0; w > (1<<ff_log2_run[i]); i++)
+ int s = 1 + w / (1<<23);
+ int i;
+
+ w /= s;
+
+ for (i = 0; w > (1<<ff_log2_run[i]); i++)
w -= ff_log2_run[i];
- if (buf_size < (avctx->height + i + 6)/ 8)
+ if (buf_size < (avctx->height + s*i + 6)/ 8)
return AVERROR_INVALIDDATA;
}
[...]
--
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