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 ESMTPS id 693F54C1A5 for ; Wed, 5 Feb 2025 23:52:07 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id B22BF68B9B5; Thu, 6 Feb 2025 01:52:03 +0200 (EET) Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 5C01868B797 for ; Thu, 6 Feb 2025 01:51:57 +0200 (EET) Received: by mail.gandi.net (Postfix) with ESMTPSA id 81AEC41B45 for ; Wed, 5 Feb 2025 23:51:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=niedermayer.cc; s=gm1; t=1738799516; 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=JBMPKsJcRztPyzKj9gIVLlfU6MySqzHP0kF0JGAnVz4=; b=KkYUxCAqsuI+r6t2v7qRNt78mm86TSmSV61PY1PTTd3HIj7g819w8+jMrhR13MUiJqsL4u YveD7wXxD2WndrHmOV8YcAy26gERzmwjGxq08jh2yG//x5BXvIknyfmmnV9ZuVvzozMwFC /w66tBqdgLS8qNfPRIxr12VbtnrsfXo6uMVmwbggStAeKTnuUrZdgxWglXw8n+mN9xOO64 jPBAy8+7LSb5KGhwh5Y1r23SMJkS9EqFrT/lpQ6zAyxhoSe3I1PjOj4bYQ0KSU9ASHHLuX v4nEdOxFT/DZReaR58MnkwX+NoQB5U40vnekc6Y9KEUeVclKBKQbe96n9O+Z5w== Date: Thu, 6 Feb 2025 00:51:55 +0100 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20250205235155.GH4991@pb2> References: <20250128142421.337241-1-michael@niedermayer.cc> <20250128142421.337241-2-michael@niedermayer.cc> <20250128214418.GY4991@pb2> <20250205184139.GD4991@pb2> MIME-Version: 1.0 In-Reply-To: <20250205184139.GD4991@pb2> X-GND-State: clean X-GND-Score: -70 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvgeekgecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnegfrhhlucfvnfffucdlfedtmdenucfjughrpeffhffvuffkfhggtggujgesghdtreertddtvdenucfhrhhomhepofhitghhrggvlhcupfhivgguvghrmhgrhigvrhcuoehmihgthhgrvghlsehnihgvuggvrhhmrgihvghrrdgttgeqnecuggftrfgrthhtvghrnhepieegkedtjeduffejhfetgeejtdegteetgfegtdfhjefgvefhteegkeejtddvhfevnecukfhppeeguddrieeirdeijedruddufeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeeguddrieeirdeijedruddufedphhgvlhhopehlohgtrghlhhhoshhtpdhmrghilhhfrhhomhepmhhitghhrggvlhesnhhivgguvghrmhgrhigvrhdrtggtpdhnsggprhgtphhtthhopedupdhrtghpthhtohepfhhfmhhpvghgqdguvghvvghlsehffhhmphgvghdrohhrgh X-GND-Sasl: michael@niedermayer.cc Subject: Re: [FFmpeg-devel] [PATCH 2/2] avformat/hls: .ts is always ok even if its a mov/mp4 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="===============7985204597829773996==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============7985204597829773996== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="bRGIdiXGEYqAuB6+" Content-Disposition: inline --bRGIdiXGEYqAuB6+ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi On Wed, Feb 05, 2025 at 07:41:39PM +0100, Michael Niedermayer wrote: > Hi Kacper >=20 > On Tue, Feb 04, 2025 at 12:45:14PM +0100, Kacper Michajlow wrote: > [...] > > security benefits. I get it. Someone needed to hit their KPI by > > submitting CVEs, and they found a marginally applicable case of a > > highly unrealistic attack scenario. >=20 > I think you mis judge the (un)realism of this attack >=20 > prior to the patches, i can give you a m3u8 file and it will store > any local file in the output video >=20 > This is not even just a matter of video streaming services, > With a bit of social engeneering you can likely get people to > do that. > "Hey i found this odd file that encodes to different gibberish > on each machien, iam an artist, doing an art project, can you > just quickly reencode this and send me the mkv it generates ?" >=20 > Who would think that above will effectively give the attacker full > access to your machiene. unless you run this in a sandbox that has > no access to sensitve files Ive tried to write an exploit for this and luckily it is not that simple. We can use data:// to feed both data and extension to force a demuxer of our choice to be used We can use crypto: to encrypt the extracted data so the user has no clue what is extracted And we dont need to have any probe succeed on the file we read. The tty_extensions check also is not helping as it is not run on the target I can read any file but only if it has a extension on the allowed_extensions list or allowed_extensions is set to ALL. This makes this luckily indeed difficult to exploit, i failed to find a way to bypass this. But there are several close ones concatdec uses data:// if we open it that way file:// is subject to teh allowed_extensions check other things like references in other demuxers i have not tried thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Complexity theory is the science of finding the exact solution to an approximation. Benchmarking OTOH is finding an approximation of the exact --bRGIdiXGEYqAuB6+ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEKAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCZ6P5mAAKCRBhHseHBAsP q7PTAJ9aQchQNoXTmG+t9eG8emmC4zupzgCeJXlkUOx6O02V5A4Mp5ygGmJPMWg= =+1R1 -----END PGP SIGNATURE----- --bRGIdiXGEYqAuB6+-- --===============7985204597829773996== 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". --===============7985204597829773996==--