From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id D77A847214 for ; Sat, 30 Sep 2023 20:18:52 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 38B8668CCFB; Sat, 30 Sep 2023 23:18:48 +0300 (EEST) Received: from mail0.khirnov.net (unknown [176.97.15.12]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id CE81A68CC0E for ; Sat, 30 Sep 2023 23:18:41 +0300 (EEST) Received: from localhost (localhost [IPv6:::1]) by mail0.khirnov.net (Postfix) with ESMTP id 49CEE240490 for ; Sat, 30 Sep 2023 22:18:39 +0200 (CEST) Received: from mail0.khirnov.net ([IPv6:::1]) by localhost (mail0.khirnov.net [IPv6:::1]) (amavis, port 10024) with ESMTP id SEnKM7BKjtwD for ; Sat, 30 Sep 2023 22:18:38 +0200 (CEST) Received: from lain.khirnov.net (lain.khirnov.net [IPv6:2001:67c:1138:4306::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "lain.khirnov.net", Issuer "smtp.khirnov.net SMTP CA" (verified OK)) by mail0.khirnov.net (Postfix) with ESMTPS id 8A89C240445 for ; Sat, 30 Sep 2023 22:18:38 +0200 (CEST) Received: by lain.khirnov.net (Postfix, from userid 1000) id 65B2C1601B9; Sat, 30 Sep 2023 22:18:38 +0200 (CEST) From: Anton Khirnov To: FFmpeg development discussions and patches In-Reply-To: <20230930143143.GL3543730@pb2> References: <20230929232001.23197-1-michael@niedermayer.cc> <47b96a8-db6b-aa20-d48-a6d60f0e84e@passwd.hu> <20230930140403.GK3543730@pb2> <20230930143143.GL3543730@pb2> Mail-Followup-To: FFmpeg development discussions and patches Date: Sat, 30 Sep 2023 22:18:38 +0200 Message-ID: <169610511838.6638.13529422310033823704@lain.khirnov.net> User-Agent: alot/0.8.1 MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] [PATCH 1/6] avformat/avidec: support huge durations X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: 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 > > > > --- > > > > 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. Do we expect such huge durations in actual files rather than fuzzed ones? Would it not be better to just not export the duration at all when the computation would overflow? -- Anton Khirnov _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".