On Sat, Sep 30, 2023 at 10:18:38PM +0200, Anton Khirnov wrote: > Quoting Michael Niedermayer (2023-09-30 16:31:43) > > On Sat, Sep 30, 2023 at 04:04:03PM +0200, Michael Niedermayer wrote: > > > On Sat, Sep 30, 2023 at 11:35:19AM +0200, Marton Balint wrote: > > > > > > > > > > > > On Sat, 30 Sep 2023, Michael Niedermayer wrote: > > > > > > > > > Fixes: signed integer overflow: 109817402400 * 301990077 cannot be > > > > > represented in type 'long long' > > > > > Fixes: > > > > > 51896/clusterfuzz-testcase-minimized-ffmpeg_dem_AVI_fuzzer-6706191715139584 > > > > > > > > > > Found-by: continuous fuzzing process > > > > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > > > --- > > > > > libavformat/avidec.c | 12 ++++++++++-- > > > > > 1 file changed, 10 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/libavformat/avidec.c b/libavformat/avidec.c > > > > > index 00bd7a98a9d..cfc693842b7 100644 > > > > > --- a/libavformat/avidec.c > > > > > +++ b/libavformat/avidec.c > > > > > @@ -27,6 +27,7 @@ > > > > > #include "libavutil/avstring.h" > > > > > #include "libavutil/opt.h" > > > > > #include "libavutil/dict.h" > > > > > +#include "libavutil/integer.h" > > > > > #include "libavutil/internal.h" > > > > > #include "libavutil/intreadwrite.h" > > > > > #include "libavutil/mathematics.h" > > > > > @@ -476,7 +477,7 @@ static int calculate_bitrate(AVFormatContext *s) > > > > > AVStream *st = s->streams[i]; > > > > > FFStream *const sti = ffstream(st); > > > > > int64_t duration; > > > > > - int64_t bitrate; > > > > > + int64_t bitrate = 0; > > > > > > > > > > for (j = 0; j < sti->nb_index_entries; j++) > > > > > len += sti->index_entries[j].size; > > > > > @@ -484,7 +485,14 @@ static int calculate_bitrate(AVFormatContext *s) > > > > > if (sti->nb_index_entries < 2 || st->codecpar->bit_rate > 0) > > > > > continue; > > > > > duration = sti->index_entries[j-1].timestamp - > > > > > sti->index_entries[0].timestamp; > > > > > - bitrate = av_rescale(8*len, st->time_base.den, duration * > > > > > st->time_base.num); > > > > > + if (INT64_MAX / duration >= st->time_base.num) { > > > > > + bitrate = av_rescale(8*len, st->time_base.den, duration > > > > > * st->time_base.num); > > > > > > > > Why not always use the AVInteger version? This is not performance > > > > sensitive > > > > as far as I see. > > > > > > We can, i will have to fix the rounding though so it matches av_rescale() > > > > will apply this with just AVInteger and fixed rounding with my next push > > probably > > This seems MUCH less readable to me.
we can add a av_rescale_2den() > > Do we expect such huge durations in actual files rather than fuzzed > ones? no, i dont expect that. > Would it not be better to just not export the duration at all when > the computation would overflow? Better ? i dont know if i scale that idea up and replace EVERY computation with a subset that seems enough and prettier. I think that would not result in overall very robust or clean code. If its better to do it just here i dont know but ill do whatever people prefer thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I know you won't believe me, but the highest form of Human Excellence is to question oneself and others. -- Socrates
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".
