On Wed, Sep 15, 2021 at 10:09:49PM +0200, Andreas Rheinhardt wrote: > Michael Niedermayer: > > Fixes: signed integer overflow: 559334865 * 4 cannot be represented in type > > 'int' > > Fixes: > > 37929/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-6751932295806976 > > > > Found-by: continuous fuzzing process > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > --- > > libavcodec/apedec.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c > > index bf481ba3549..23318be0613 100644 > > --- a/libavcodec/apedec.c > > +++ b/libavcodec/apedec.c > > @@ -1337,7 +1337,7 @@ static void do_apply_filter(APEContext *ctx, int > > version, APEFilter *f, > > absres = FFABSU(res); > > if (absres) > > *f->adaptcoeffs = APESIGN(res) * > > - (8 << ((absres > f->avg * 3) + (absres > > > f->avg * 4 / 3))); > > + (8 << ((absres > f->avg * 3) + (absres > > > f->avg * 4LL / 3))); > > /* equivalent to the following code > > if (absres <= f->avg * 4 / 3) > > *f->adaptcoeffs = APESIGN(res) * 8; > > > How about using f->avg + f->avg / 3? Given that you haven't modified the > f->avg * 3 before, this should be save.
not anymore, the *3 overflows too in 39172/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-638602483033702 [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Many that live deserve death. And some that die deserve life. Can you give it to them? Then do not be too eager to deal out death in judgement. For even the very wise cannot see all ends. -- Gandalf
signature.asc
Description: PGP signature
_______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
