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 BB94F3E3DAA; Mon, 4 May 2026 17:48:53 +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=1777916933; cv=none; b=Mqzu7eBeoB0PErT29CCyCDWlCV0aak0maRgbq7EEu7OG1a0XKbfUbtEQActGXc3S75GKRxvYeO+ouK2VxGxKsFxLiJvBhYtKxz8C6SC2Dw1w8dzrIvM3RKb5/1NfFWyfezhWktLyrgw4pl4mT5QlUeCrRkbZM8m1EGjcPcwb+wg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777916933; c=relaxed/simple; bh=HBm2VfYhCqoM+ORUtihoa//7kAyARXAwfAerXmia3lE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lNP3Lghwhy+h8ErO4C7opUsarRwywVRMn/ICXPFi1mogXeSuGC9om9v+0gJd6VYYM3CkvsCEcVXyFCHNFwmbXSqxa6HgD1E3R3UOb0taG/t+3Ci7hZVHfQkiZHUcrcxnHBc8q5tp1e9FpotlfOqfcbrUoUFHxVcmIChjgX3T3Rw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PAyW4P3k; 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="PAyW4P3k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13EE6C2BCB8; Mon, 4 May 2026 17:48:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777916933; bh=HBm2VfYhCqoM+ORUtihoa//7kAyARXAwfAerXmia3lE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PAyW4P3kOztDaDUVLckYcoAzPXGAP33jHS5um0+VVvDfHhFwpcjezAacfX6/8z7Ul 7PkAZ+Dvc793T9B/Mi9KcHxvJng40THWFKe2OvBrti9s6XuY9yOF8Z1AdU3tI74FJ5 CeILmQ+0D+InEzyneWGOiJtdGjR7x7HmQx0oGHbxBM2+vvuMZ7eQH2OInoeOY+8kA6 dYNDgXrOIG85CmIFbSPhVVrjTokDBCcp2HIYuJiYVoRWvjfx8KGOuwxe/AWkKb2a22 jNQbhZ4jlu+DlObq3eLWWa4dqm2G4xxVo0KN6c4c1YRu3gMwO6YLdI8oaom0k3K4JD wW66v0zrwA7+w== Date: Mon, 4 May 2026 10:47:33 -0700 From: Eric Biggers To: =?utf-8?B?4pK2bMOvIFDimK5sYXRlbA==?= Cc: linux-crypto@vger.kernel.org, Herbert Xu , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Taeyang Lee <0wn@theori.io>, Brian Pak , Juno Im , Jungwon Lim , Tim Becker , Demi Marie Obenour , Feng Ning , stable@vger.kernel.org Subject: Re: [PATCH] crypto: af_alg - Remove zero-copy support from AF_ALG Message-ID: <20260504174733.GB2291@sol> References: <20260504061532.172013-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, May 04, 2026 at 04:07:45PM +0000, Ⓐlï P☮latel wrote: > Syd sandbox uses AF_ALG zero-copy for its Force Sandboxing[1] and Crypt Sandboxing[1]. > Zero-copy means Syd does not have to copy sandbox process data into its own address > space providing safety and security. Switching to read/write rather than pipes and > splice breaks a fundamental safety guarantee for the sandbox. Please do not break > userspace. > > Will sendfile(2) continue to work? > > [1]: https://man.exherbo.org/syd.7.html#Force_Sandboxing > [2]: https://man.exherbo.org/syd.7.html#Crypt_Sandboxing It's very unclear what that feature (which I don't think anyone knew even existed) is trying to accomplish. Regardless, this patch doesn't break the splice or sendfile syscalls. It just makes them run a bit more slowly since the kernel will copy the data internally. So I think your concern isn't justified. > How can i test? Please help me. If this is a feature you care about, perhaps you know how to test it? - Eric