From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <ffmpeg-devel-bounces@ffmpeg.org> Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 513654AFCB for <ffmpegdev@gitmailbox.com>; Tue, 25 Jun 2024 23:27:47 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id E8AF668D636; Wed, 26 Jun 2024 02:27:44 +0300 (EEST) Received: from relay1-d.mail.gandi.net (relay1-d.mail.gandi.net [217.70.183.193]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 3E90F68C75C for <ffmpeg-devel@ffmpeg.org>; Wed, 26 Jun 2024 02:27:38 +0300 (EEST) Received: by mail.gandi.net (Postfix) with ESMTPSA id 95A93240004 for <ffmpeg-devel@ffmpeg.org>; Tue, 25 Jun 2024 23:27:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=niedermayer.cc; s=gm1; t=1719358057; 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=m6baTBU2GgK8sUG8DcCf8J9wqwdSdyAeG6NxOteYd5o=; b=O+HQau56K0P6LSMEHVnNRGFUvWm7E5SqclOu0HyKmpOFbBZfOj6zZ2BEV38am1TaUQSeBl sNmCh9oAYrqq8k7IrMakkVCcQ36gybvx/4Yz1buVFIKe7m4gBIjnQB6m19dGflyIgqJxhh 5Xd2P1AJX9cqP611JMGqRoggbYPktprxGnXGcnUpeA2btfYM88KIcQHgqBCB4FTtsLHzR1 rGzZYV+A3z4zIC7wuZ1lpwRoJeM6cPyVScmzOzJ3/SU+JYnLbyYIDFqq3FNC+ihllDFkby hFg82O3t3RYYxTQLLTn2IdNuPiBS9LpD8bF3RDxzCDzvYUEOacUrYRIRK4ptDw== Date: Wed, 26 Jun 2024 01:27:36 +0200 From: Michael Niedermayer <michael@niedermayer.cc> To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org> Message-ID: <20240625232736.GO4991@pb2> References: <20240623230137.1749178-1-michael@niedermayer.cc> <20240623230137.1749178-2-michael@niedermayer.cc> <171930595471.21847.5930175805645108289@lain.khirnov.net> MIME-Version: 1.0 In-Reply-To: <171930595471.21847.5930175805645108289@lain.khirnov.net> X-GND-Sasl: michael@niedermayer.cc Subject: Re: [FFmpeg-devel] [PATCH 2/5] avcodec/hevc/hevcdec: Do not allow changes to parameter sets between slices 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="===============5082799689641643064==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" <ffmpeg-devel-bounces@ffmpeg.org> Archived-At: <https://master.gitmailbox.com/ffmpegdev/20240625232736.GO4991@pb2/> List-Archive: <https://master.gitmailbox.com/ffmpegdev/> List-Post: <mailto:ffmpegdev@gitmailbox.com> --===============5082799689641643064== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="pndui+VhQ7yNUqd0" Content-Disposition: inline --pndui+VhQ7yNUqd0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 25, 2024 at 10:59:14AM +0200, Anton Khirnov wrote: > Quoting Michael Niedermayer (2024-06-24 01:01:34) > > The slice code detects changes by comparing the pps index. > > That way the code cannot detect changes if the sets can change. > >=20 > > Fixes: out of array access > > Fixes: 69585/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuz= zer-6389604524556288 > > Fixes: 69601/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuz= zer-5069068613255168 > > Fixes: 69621/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuz= zer-6187334182174720 > >=20 > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz= /tree/master/projects/ffmpeg > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavcodec/hevc/hevcdec.c | 3 +++ > > 1 file changed, 3 insertions(+) > >=20 > > diff --git a/libavcodec/hevc/hevcdec.c b/libavcodec/hevc/hevcdec.c > > index 1d2e53afc32..d68d454537a 100644 > > --- a/libavcodec/hevc/hevcdec.c > > +++ b/libavcodec/hevc/hevcdec.c > > @@ -3221,17 +3221,20 @@ static int decode_nal_unit(HEVCContext *s, cons= t H2645NAL *nal) > > ret =3D ff_hevc_decode_nal_vps(&gb, s->avctx, &s->ps); > > if (ret < 0) > > goto fail; > > + s->sh.pps_id =3D -1; >=20 > This is backwards. If the problem is that the current check does not > detect the change, then the check should be fixed. The specification explcitly doesnt allow the active *PS to change "Any PPS NAL unit containing the value of pps_pic_parameter_set_id for the = active PPS RBSP for a coded picture (and consequently for the layer containing the coded picture) shall have the sam= e content as that of the active PPS RBSP for the coded picture, unless it follows the last VCL NAL unit of the coded picture= and precedes the first VCL NAL unit of another coded picture." "Any SPS NAL unit with nuh_layer_id equal to 0 containing the value of sps_= seq_parameter_set_id for the active SPS RBSP for the base layer for a CVS shall have the same content as that of th= e active SPS RBSP for the base layer for the CVS, unless it follows the last access unit of the CVS and precedes the fir= st VCL NAL unit and the first SEI NAL unit containing an active parameter sets SEI message (when present) of another C= VS." "Any SPS NAL unit with any nuh_layer_id value containing the value of sps_s= eq_parameter_set_id for the active SPS RBSP for a particular layer shall have the same content as that of the acti= ve SPS RBSP for the particular layer unless it follows the access unit auA containing the last coded picture for which the= active SPS RBSP for the particular layer is required to be active for the particular layer and precedes the first NAL u= nit succeeding auA in decoding order that activates an SPS RBSP with the same value of seq_parameter_set_id." So if anything fancy is wanted, the way to go is not to parse it in the fir= st place. Because if it matches then the parsing was a waste of time. If it mismatche= s, that would be invalid and would just lead to failure anyway But really the primary goal is to fix the out of array access and be easy to backport. I am not trying to fix this in a fancy way. The simpler and more robust the fix is the better. thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety -- Benjamin Franklin --pndui+VhQ7yNUqd0 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEKAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCZntSZAAKCRBhHseHBAsP q0W4AKCZSr/am/PmDTwMc6KlXUEwG0GaNgCeOFempLfJbJecsuO+K1Or+eKQa/8= =DJ/a -----END PGP SIGNATURE----- --pndui+VhQ7yNUqd0-- --===============5082799689641643064== 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". --===============5082799689641643064==--