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 870D21D555; Wed, 21 Jan 2026 00:06:10 +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=1768953970; cv=none; b=XbUHK69c7g6PmkwifjWC8UXvnQgyQB+dEoYpmZKVPoiT+H/fXTMqxa5YNB+akx4FPB3bzXJNLFQT1Y8UCIWis83hahW4fICeHN/7NpsWk86c0QtP8/75FKFTZbYO8UkPS2hLR+8WTh3JGTc9FZrR39qxCaGjhl94nYJBx/3BC9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768953970; c=relaxed/simple; bh=Zr0dKdI8zxsaxfaFyAG1kkUBLfApTCk9CJiwbxwsKCQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jhEdwKD059aXmngLVnmJ1llIGebx20vlzX7sybyE9PeoulDKYJbZ8WnThxs3DacQ8jb4+Sk46vqSNk8RUjs0nbvWPA/Ny1AzyEsgzf2o0R/jNpLivd4v+bXhyq0omZeHxB+J/UhTJ/j2O3QYWoVncKlNTlp8g6ffFq2h9g82jmA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H7LGzDff; 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="H7LGzDff" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 616E7C16AAE; Wed, 21 Jan 2026 00:06:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768953970; bh=Zr0dKdI8zxsaxfaFyAG1kkUBLfApTCk9CJiwbxwsKCQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=H7LGzDffzTRPU3xC6K6VXLfr0zWpDmVdO+arqxzcv3vHcE7AN0yPzRu0t0631o0iq N6yL9Lz6qgNKqFqo6wFdduct9lwA1ckvgY1R7ZRJX9cX6kJNWw21uZH1nlSHuioEiF qzEZ8Buk4v4zA16UzEGKM/CP8JjYlhw/MB7gNKtuGO11R/SkBA4agJpJLUJNI///2b j3e4hZ+hmXtGbRzv+fxHYN+oKNy39/IsElmkRqQMIIsgLTAKX+h1kYvPxzvWDlKhuZ HD8O/yEfL/+fHQscHM1IfpATmIMTZ/P6YXbwRFVle8pHe7YgRVZ3Zn44/ggnjOUWq9 tXOlQ2aFQ3rZw== Date: Tue, 20 Jan 2026 16:06:07 -0800 From: Eric Biggers To: David Howells Cc: Lukas Wunner , Ignat Korchagin , Jarkko Sakkinen , Herbert Xu , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , "Jason A . Donenfeld" , Ard Biesheuvel , Stephan Mueller , linux-crypto@vger.kernel.org, keyrings@vger.kernel.org, linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" Subject: Re: [PATCH v12 06/10] crypto: Add supplementary info param to asymmetric key signature verification Message-ID: <20260121000607.GA12110@quark> References: <20260120220321.GA6191@quark> <20260115215100.312611-1-dhowells@redhat.com> <20260115215100.312611-7-dhowells@redhat.com> <1418295.1768952386@warthog.procyon.org.uk> Precedence: bulk X-Mailing-List: linux-modules@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: <1418295.1768952386@warthog.procyon.org.uk> On Tue, Jan 20, 2026 at 11:39:46PM +0000, David Howells wrote: > Eric Biggers wrote: > > > As I'm sure you're aware, C has native support for function parameters. > > And we have a syscall interface to honour that takes a parameter string *for > this very purpose*. It just wasn't threaded into the akcipher API. This seems to be more of a bug than a feature, though. It seems the actual goals of this patchset are to add ML-DSA and RSASSA-PSS support to kernel module signing. But because of how the code is organized, as a side effect it ended up extending the KEYCTL_PKEY_* UAPIs as well. Linux's UAPI stability guarantee holds for these UAPIs; anything that we add to them, including these ad-hoc and undocumented parameter strings, will likely have to be supported forever. Unless these keyctl UAPI extensions are well-justified and come with documentation and tests, we should just hold off on them for now. What's the hurry? BTW, we got hit by this when there was an attempt to remove SHA-1 support from module signing. Due to the design defect where the signing is also exposed through KEYCTL_PKEY_*, it caused a UAPI regression as well and had to be reverted. - Eric