From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F09927281E; Thu, 30 Apr 2026 02:12:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777515121; cv=none; b=LPCIQeHyAov4mOEdRAh9AiW68G+tBHJNpaFxxcHniPDMejdiYPsxf4i/i+VAbbtQ8udBzdEutQ6uLh8/IumRsQGyk4jlE3/5SDzq22+Ecf7nPpF046Gow68qH81ZfeAguF4sTNdAOQkzNbSoLaQmgflRIh9MNLZtGRdnCku9Y+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777515121; c=relaxed/simple; bh=Iynk1THCP/qxdLQKKSMR/8OAJf7uHsox6KYhOKpSMU0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CinLlP1p6KdqF0nBTrYiloh2E+KZ1q98ZFUWRZgIddFDCz8L2xGip2+rHfyepSVGjzyprYBUFotq1wKPhu+feGujq94O32P5YRdYjrLI5Cf/RNrVGVqwKat0CthrbMIOpG/n67OxRvmmgN7qklgBdJvc44rpJvS9oZ0wTPJ7Lh4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=k5kPcn1Q; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="k5kPcn1Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73F8FC19425; Thu, 30 Apr 2026 02:12:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777515120; bh=Iynk1THCP/qxdLQKKSMR/8OAJf7uHsox6KYhOKpSMU0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=k5kPcn1Q1fUhwjrw0jUQbfbBGvNFQcLWfY70N66e6NxJsAlJ72hGJFLJdO/PzWgpo MLxCvYfGQpDkBNr3pnw/MT9mkIJiDXWGypfO85vxMM3hJOreGIN7mRc9e8N4nezFk3 UnF1NLTth1FY0KExLwJkQdwIojJO9kunMAGn/+w7p3neh1GrcKY3asz+9VnOgCajqI 8dyfrmHbUbPnvzcBdriDV3bJR7qoNLLsGLSfZGF6nRQrOwfelo6PUH9PVx8LEH4is4 tHc4jTR5t8aPrg4fvnYgWHkL2YMnM48nyrNzslD6/WfgwL8/AWpdwqREf2/k4JQIJn 3HN/JRZClm+lA== Date: Wed, 29 Apr 2026 19:10:42 -0700 From: Eric Biggers To: Herbert Xu Cc: linux-crypto@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Linus Torvalds , David Howells Subject: Re: [PATCH] crypto: af_alg - Document the deprecation of AF_ALG Message-ID: <20260430021042.GA51782@sol> References: <20260430011544.31823-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Apr 30, 2026 at 10:05:00AM +0800, Herbert Xu wrote: > On Wed, Apr 29, 2026 at 06:15:44PM -0700, Eric Biggers wrote: > > AF_ALG is almost completely unnecessary, and it exposes a massive attack > > surface that hasn't been standing up to modern vulnerability discovery > > tools. The latest one even has its own website, providing a small > > Python script that reliably roots most Linux distros: https://copy.fail/ > > > > This isn't sustainable, especially as LLMs have accelerated the rate the > > vulnerabilities are coming in. The effort that is being put into this > > thing is vastly disproportional to the few programs that actually use > > it, and those programs would be better served by userspace code anyway. > > > > These issues have been noted in many mailing list discussions already. > > But until now they haven't been reflected in the documentation or > > kconfig menu itself, and the vulnerabilities are still coming in. > > > > Let's go ahead and document the deprecation. > > > > This isn't intended to change anything overnight. After all, most Linux > > distros won't be able to disable the kconfig options quite yet, mainly > > because of iwd. But this should create a bit more impetus for these > > userspace programs to be fixed, and the documentation update should also > > help prevent more users from appearing. > > > > Signed-off-by: Eric Biggers > > What about the exposure of akcipher through security/keys/keyctl_pkey.c? > > There isn't even a Kconfig option to disable that user-space API. > If module signatures are enabled then this automatically gets added > to the kernel: > > MODULE_SIG -> MODULE_SIG_FORMAT -> SYSTEM_DATA_VERIFICATION -> > KEYS + ASYMMETRIC_KEY_TYPE Yes, that would be a different patch, but KEYCTL_PKEY_* have a very similar issue. That should have a kconfig option added too. I believe iwd is the main (or even only?) user there, as well. - Eric