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 B3EDC40DBF for ; Sat, 29 Jun 2024 23:37:16 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 7A87768D7CE; Sun, 30 Jun 2024 02:37:13 +0300 (EEST) Received: from relay9-d.mail.gandi.net (relay9-d.mail.gandi.net [217.70.183.199]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 1A40068D6E0 for ; Sun, 30 Jun 2024 02:37:07 +0300 (EEST) Received: by mail.gandi.net (Postfix) with ESMTPSA id 4CA98FF806 for ; Sat, 29 Jun 2024 23:37:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=niedermayer.cc; s=gm1; t=1719704226; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=6lP0AmalsQbkX1/cy7hGukuivBmLl94DJ5VbBQvQCig=; b=fXMoD2w1Tr//Z0QxAjg/lne2tdLCjgAOf4eyMI4KL29I6CwMDhvManF23L1bCNq2GjStTy AgnFet4s1xHi01Ij48el6uAb7sPUtvbPOETeejs7pb1VnUU58wvOl3geFRcpqvwjHrOPao 51SUgsGSexi59/dh7ih9eqAHtfXB5Qhnu9Kf9mLItlw0rLnDw6KipZd5vYVIOkdsFpqCoP AqvRQ0wNj8DTMhB7NGHgl+sl76/xFM0AyFTkIsRoNXah1Q26LmdwM81PSoOavrP+8ygBGP 0tgfmvEP8tode9n45kQ+WYnIWDiAilIoAjXNhXFBF0rLtVabBB0MpaP6WGsJsg== Date: Sun, 30 Jun 2024 01:37:05 +0200 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20240629233705.GB4991@pb2> References: <20240322230818.18997-1-michael@niedermayer.cc> <40908cf3-7e3a-4a57-a23e-43bf153c20bd@gmail.com> MIME-Version: 1.0 In-Reply-To: <40908cf3-7e3a-4a57-a23e-43bf153c20bd@gmail.com> X-GND-Sasl: michael@niedermayer.cc Subject: Re: [FFmpeg-devel] [PATCH 1/3] avformat/cafdec: sanity check channels and bps 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: multipart/mixed; boundary="===============3240652583975110517==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============3240652583975110517== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ARHwKispuqSRPZ/2" Content-Disposition: inline --ARHwKispuqSRPZ/2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jun 26, 2024 at 09:52:44PM -0300, James Almer wrote: > On 3/22/2024 8:08 PM, Michael Niedermayer wrote: > > Fixes: Timeout > > Fixes: 67044/clusterfuzz-testcase-minimized-ffmpeg_dem_CAF_fuzzer-57911= 44363491328 > >=20 > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz= /tree/master/projects/ffmpeg > > Signed-off-by: Michael Niedermayer > > --- > > libavformat/cafdec.c | 5 +++++ > > 1 file changed, 5 insertions(+) > >=20 > > diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c > > index 426c56b9bd..334077efb5 100644 > > --- a/libavformat/cafdec.c > > +++ b/libavformat/cafdec.c > > @@ -33,6 +33,7 @@ > > #include "isom.h" > > #include "mov_chan.h" > > #include "libavcodec/flac.h" > > +#include "libavcodec/internal.h" > > #include "libavutil/intreadwrite.h" > > #include "libavutil/intfloat.h" > > #include "libavutil/dict.h" > > @@ -87,6 +88,10 @@ static int read_desc_chunk(AVFormatContext *s) > > st->codecpar->ch_layout.nb_channels =3D avio_rb32(pb); > > st->codecpar->bits_per_coded_sample =3D avio_rb32(pb); > > + if (st->codecpar->ch_layout.nb_channels > FF_SANE_NB_CHANNELS || > > + st->codecpar->bits_per_coded_sample > 64) >=20 > Where does the process take so long that oss-fuzz gets a timeout if these > are unreasonably high? I don't see nb_channels used anywhere in here where > that matters. > Is it in the PCM decoder? Because that decoder is meant to handle any > arbitrary amount of channels, so limiting it to whatever FF_SANE_NB_CHANN= ELS > is set to is not ok. libavutil/channel_layout.c:627:17 or it will OOM before depending on how much memory is available >=20 > And is the bits_per_coded_sample > 64 check to prevent codec_id being > AV_CODEC_ID_NONE? if so, how does that affect demuxing time? > AV_CODEC_ID_NONE for that matter could happen for valid files with a codec > we don't currently support. We generally check read values for validity at the earliest, bits_per_coded_sample of more than 64 seem not valid to me. thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I have never wished to cater to the crowd; for what I know they do not approve, and what they approve I do not know. -- Epicurus --ARHwKispuqSRPZ/2 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEKAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCZoCaoAAKCRBhHseHBAsP q5l9AJ0fKy+P9cAFRrY00UAb0Jimkg5CPACcDR7qEigXgERhswXKNgHD3KiECOU= =HQHH -----END PGP SIGNATURE----- --ARHwKispuqSRPZ/2-- --===============3240652583975110517== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ 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". --===============3240652583975110517==--