From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <ffmpeg-devel-bounces@ffmpeg.org> Received: from ffbox0-bg.ffmpeg.org (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTPS id 95C574C3D0 for <ffmpegdev@gitmailbox.com>; Mon, 23 Jun 2025 14:20:05 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.ffmpeg.org (Postfix) with ESMTP id 9A47B68DABE; Mon, 23 Jun 2025 17:20:00 +0300 (EEST) Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) by ffbox0-bg.ffmpeg.org (Postfix) with ESMTPS id 5FE5568DA64 for <ffmpeg-devel@ffmpeg.org>; Mon, 23 Jun 2025 17:19:54 +0300 (EEST) Received: by mail.gandi.net (Postfix) with ESMTPSA id BE7C343940 for <ffmpeg-devel@ffmpeg.org>; Mon, 23 Jun 2025 14:19:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=niedermayer.cc; s=gm1; t=1750688393; 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=UKCYfA15Y/IL5vGI39G9Kmx+CQZyXnyZlWzWmPRSEyc=; b=S+Nh8k6kEQ8LIgiA/oL9B2PH2AXT7UBX14m2YQB84GJZblSr4ThamBECqYG7D2BXtKnIfT XNRVviLsaseOn9mAyuzNLxPSYf7PYYeCac9JD/7OnWaqOYuG3m/xEpaEQuN9GrpxTWQtIs rBENz8b8lzR+4v8VmdwHNuQO+nIZ5FE+SVOz6Ww9d34tfVlAZM0Wu6DCwW1AiCtXmvAK4G HT7K9YsAhBJm91nLY+c3hbTLg9LCaxQUBPrHNyIktTcdWoOUM+vv1uKqeb9opUbXyvlc7C Xdr5pt10ht03utBH2P1J3ADak9LC0mkJKlCUcUM3kH/aeJqU2QrDQGQzNfwWAQ== Date: Mon, 23 Jun 2025 16:19:52 +0200 From: Michael Niedermayer <michael@niedermayer.cc> To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org> Message-ID: <20250623141952.GL29660@pb2> References: <20250619030432.2977718-1-michael@niedermayer.cc> <GV1P250MB07379CFCFF5E6E6893069B998F7DA@GV1P250MB0737.EURP250.PROD.OUTLOOK.COM> <20250623124404.GI29660@pb2> <8c820149-1664-424a-8a6d-bf4573bab04f@gmail.com> MIME-Version: 1.0 In-Reply-To: <8c820149-1664-424a-8a6d-bf4573bab04f@gmail.com> X-GND-State: clean X-GND-Score: -85 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddvgddujedvhecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnegfrhhlucfvnfffucdludehmdenucfjughrpeffhffvuffkfhggtggujgesghdtreertddtvdenucfhrhhomhepofhitghhrggvlhcupfhivgguvghrmhgrhigvrhcuoehmihgthhgrvghlsehnihgvuggvrhhmrgihvghrrdgttgeqnecuggftrfgrthhtvghrnheptefggedvffeiueffvefhiedtgfefjedukeefgeetgeevgeejgeekvdevjeelveeknecuffhomhgrihhnpehgihhthhhusgdrtghomhenucfkphepgedurdeiiedrieejrdduudefnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepgedurdeiiedrieejrdduudefpdhhvghloheplhhotggrlhhhohhsthdpmhgrihhlfhhrohhmpehmihgthhgrvghlsehnihgvuggvrhhmrgihvghrrdgttgdpnhgspghrtghpthhtohepuddprhgtphhtthhopehffhhmphgvghdquggvvhgvlhesfhhfmhhpvghgrdhorhhg X-GND-Sasl: michael@niedermayer.cc Subject: Re: [FFmpeg-devel] [PATCH 1/4] avformat/iamf_parse: Check extradata size X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches <ffmpeg-devel.ffmpeg.org> List-Unsubscribe: <https://ffmpeg.org/mailman/options/ffmpeg-devel>, <mailto:ffmpeg-devel-request@ffmpeg.org?subject=unsubscribe> List-Archive: <https://ffmpeg.org/pipermail/ffmpeg-devel> List-Post: <mailto:ffmpeg-devel@ffmpeg.org> List-Help: <mailto:ffmpeg-devel-request@ffmpeg.org?subject=help> List-Subscribe: <https://ffmpeg.org/mailman/listinfo/ffmpeg-devel>, <mailto:ffmpeg-devel-request@ffmpeg.org?subject=subscribe> Reply-To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org> Content-Type: multipart/mixed; boundary="===============1998967267202735060==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" <ffmpeg-devel-bounces@ffmpeg.org> Archived-At: <https://master.gitmailbox.com/ffmpegdev/20250623141952.GL29660@pb2/> List-Archive: <https://master.gitmailbox.com/ffmpegdev/> List-Post: <mailto:ffmpegdev@gitmailbox.com> --===============1998967267202735060== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="5anOi6y0P/EXwi56" Content-Disposition: inline --5anOi6y0P/EXwi56 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jun 23, 2025 at 09:47:55AM -0300, James Almer wrote: > On 6/23/2025 9:44 AM, Michael Niedermayer wrote: > > On Fri, Jun 20, 2025 at 12:28:13AM +0200, Andreas Rheinhardt wrote: > > > Michael Niedermayer: > > > > Fixes: Assertion n>=3D0 && n<=3D32 failed at ./libavcodec/get_bits.= h:406 > > > > Fixes: 398527871/clusterfuzz-testcase-minimized-ffmpeg_dem_IAMF_fuz= zer-6602025714647040 > > > >=20 > > > > Found-by: continuous fuzzing process https://github.com/google/oss-= fuzz/tree/master/projects/ffmpeg > > > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > > > --- > > > > libavformat/iamf_parse.c | 2 ++ > > > > 1 file changed, 2 insertions(+) > > > >=20 > > > > diff --git a/libavformat/iamf_parse.c b/libavformat/iamf_parse.c > > > > index 71497876ac3..330e01733dd 100644 > > > > --- a/libavformat/iamf_parse.c > > > > +++ b/libavformat/iamf_parse.c > > > > @@ -305,6 +305,8 @@ static int update_extradata(AVCodecParameters *= codecpar) > > > > skip_bits(&gb, 4); > > > > put_bits(&pb, 4, codecpar->ch_layout.nb_channels); // set= channel config > > > > ret =3D put_bits_left(&pb); > > > > + if (ret < 0) > > > > + return AVERROR_INVALIDDATA; > > > > while (ret >=3D 32) { > > > > put_bits32(&pb, get_bits_long(&gb, 32)); > > > > ret -=3D 32; > > >=20 > > > There is only one way for put_bits_left() to return a negative value:= If > > > there is more data in the internal buffer than can be written out. And > > > this scenario is already a violation of the PutBit API. Given that the > > > size of the internal buffer depends upon the arch, it could be that o= ne > > > would have already hit an assert in case one is not using x64. In oth= er > > > words, your check is too late. > >=20 > > the patches puprose was mainly to show that > > 3f9420132441345b7ccd57001f230bb98f655696 > > was insufficient to fix 398527871 > >=20 > > I do not expect my patch would be the correct solution even if the > > check is done earlier. IAMF is cursed >=20 > Does increasing buf from 6 bytes to 8 or more fix it? I see putbits may do > an AV_W*64(), so six bytes sounds like it was never safe. i set buffer to 1000 and it still fails with put_bits_left() returning -19 what will fix this specific case is: - if (ret =3D=3D 0x0f) - put_bits(&pb, 24, get_bits(&gb, 24)); + if (ret =3D=3D 0x0f) { + if (get_bits_left(&gb) >=3D 24+4+4) + put_bits(&pb, 24, get_bits(&gb, 24)); + } thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB What does censorship reveal? It reveals fear. -- Julian Assange --5anOi6y0P/EXwi56 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEKAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCaFlifwAKCRBhHseHBAsP q6dJAJwOHgi0bTFz+I8fcMSzA/TWz3Jr2gCdFmcwjk7aM88psgfT8j7VLm/u+bs= =OCDT -----END PGP SIGNATURE----- --5anOi6y0P/EXwi56-- --===============1998967267202735060== 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". --===============1998967267202735060==--