Hi Manuel On Fri, May 30, 2025 at 10:54:01PM +0200, Manuel Lauss wrote: > Hi Michael, > > On Fri, May 30, 2025 at 9:52 PM Michael Niedermayer > <mich...@niedermayer.cc> wrote: > > > > Hi Manual > > > > On Wed, May 14, 2025 at 03:39:53AM +0200, Michael Niedermayer wrote: > > > k is always 4 here and it seems this is not what was intended > > > replacing it with 0 works but it may be wrong > > > > > > This needs review > > > > > > Fixes: out of array read > > > Fixes: > > > 409593384/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SANM_fuzzer-6488251907244032 > > > > > > Found-by: continuous fuzzing process > > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > --- > > > libavcodec/sanm.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > please review, this patch is just written based on gut feeling, > > its just clear that the code before was buggy > > > > > > > diff --git a/libavcodec/sanm.c b/libavcodec/sanm.c > > > index 00bfef00fe8..ec429e1a002 100644 > > > --- a/libavcodec/sanm.c > > > +++ b/libavcodec/sanm.c > > > @@ -734,7 +734,7 @@ static int old_codec4(SANMVideoContext *ctx, > > > GetByteContext *gb, int top, int le > > > } > > > > > > /* smooth top and left block borders with neighbours */ > > > - if (((pxoff - p + k) < 0) || ((pxoff - p + k) >= maxpxo) > > > + if (((pxoff - p + 0) < 0) || ((pxoff - p + k) >= maxpxo) > > > || ((pxoff + 3 * p) < 0) || ((pxoff + 3 * p) >= maxpxo) > > > || (i == 0) || (j == 0)) > > > continue; > > Oops, yes, that change is correct.
will apply > I think you should just rip the whole block-smoothing block out > entirely: it creates a "sawtooth" pattern > which is more annoying than the "blockiness" it tries to soften. probably, but i just wanted to fix the out of array access, ill leave improvment beyond that to others thx -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Rewriting code that is poorly written but fully understood is good. Rewriting code that one doesnt understand is a sign that one is less smart than the original author, trying to rewrite it will not make it better.
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