From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 2181F486B9A; Tue, 13 Oct 2026 17:35:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791912921; cv=none; b=RVJcmA7Pe3O0wsSwDfN5zijxZWM+GdYYBy53G3uC/nivx3xLJrOcB4JuYYkpthlbOSWJWzckWFQFUOfvOdUxcnaP2xAA5Yi0gSnqBUowzOSQth6jvBtIEg34jBx396vqF7Ivdy3BTS0y4M6zEIHOrR5Hs+Bf4zoHlLxCm5easkY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791912921; c=relaxed/simple; bh=4twf8Ig83j6rkVDnor3DhOBVrA0QW/ohTKWyuUpG2IU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=So/zJlpIlVWZr7llgGGcg5nq/KnJhp1hG65kb+X/QsaIWkrJ90HzLq74ZjDN1q2vk6TfuIdv2xCyy31IbA27hCNLyoIum5hH7VAj//VfrOt6vv/1r0J58CaixEm+jTIdz6KFGZsGrMWlkERjQwJw5HyrK31Jj88/345kDtZdmgk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oMqQOCXC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oMqQOCXC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81A9A1F000FF; Tue, 13 Oct 2026 17:35:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791912919; bh=khTJvLKv/+vOyw+yWXKAIK2ePXBBTi6nmBmOdNZF1bE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=oMqQOCXCThSpiERo+J2ssNIxZSBPR/i04TI56b3HPg93nuwHeSySq6TcZ+W9B1BfO 9JQNaL3PM0yzxFAH99mc2X7kX0kSJpIO5Y3okHhq1lczj08fcEv+p2vf4JZLI1T1YO lAmDVAze1RHqnVkLHe6WMw/h0GfYZSWLrzxk6DFWGF1Hg3CPMSvnzL99N9X+0H04Td 4oVhwjTzTiV/Qr649AhK3Km50FccntIee9ZJyRCBHtfZJv12rnAS+YujVVmsDf3Sbd V210kbDPOhUDUexFzYUrkL75BsdSI7pTnaTPXm++NPfvhlhWKMZTwBjqAKJhVNEH8s WRObtjnrJ5j8A== Date: Tue, 13 Oct 2026 19:35:08 +0200 From: Eric Biggers To: vladimir@genproof.com Cc: Herbert Xu , "David S. Miller" , "Jason A. Donenfeld" , Ard Biesheuvel , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-mips@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti Subject: Re: [PATCH 0/5] lib/crypto: Handle large lengths in poly1305 and chacha20poly1305 Message-ID: <20261013173508.GB3830@quark> References: <20261012-libcrypto-4gib-lengths-v1-0-ea566c129a2e@genproof.com> Precedence: bulk X-Mailing-List: linux-mips@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: <20261012-libcrypto-4gib-lengths-v1-0-ea566c129a2e@genproof.com> On Mon, Oct 12, 2026 at 09:31:17PM +0000, Vladimir Kukharenko via B4 Relay wrote: > This series makes the Poly1305 and ChaCha20-Poly1305 library code handle > large lengths: > > - poly1305_update() can write past its 16-byte buffer if it holds a > partial block and nbytes >= 2^32 - desc->buflen. > - The chacha20poly1305 functions use only the low 32 bits of their > size_t message and associated data lengths. > - On 64-bit MIPS and RISC-V, the poly1305 assembly reads past its input > for lengths of 2 GiB or more: these ABIs sign-extend its u32 length > argument, and the assembly uses all 64 bits. arm64 has the same > prototype mismatch, with no known failure. > > Patches 1-3 fix the assembly prototypes, one architecture per patch. > The assembly already treats the length as 64-bit, so they declare it as > size_t, as commit f3d6cb3dc039 ("lib/crypto: x86/sha1: Migrate > optimized code into library") did for the x86 SHA-1 assembly. > Patches 4 and 5 make poly1305_update() and chacha_crypt() take size_t > lengths. The patches apply independently, except that on 64-bit MIPS > and RISC-V patch 4 relies on patches 1 and 2 for inputs of 2 GiB or more. > > No in-tree caller passes inputs this large (WireGuard passes at most one > packet, big_key at most 1 MiB), so I consider these ABI robustness > improvements rather than fixes and have not added Fixes or Cc stable tags. > > I tested with the lib/crypto KUnit suite on UML, x86_64, i386, arm64, > riscv64 and mips64, with a temporary 2 GiB KUnit test on arm64, riscv64 > and mips64 (it oopses on riscv64 and mips64 without patches 1 and 2), and > in userspace against OpenSSL for inputs above 4 GiB. > > I found the bugs fixed by patches 4 and 5 while writing Coq/VST proofs of > this code with LLM agents, and an LLM review of patch 4 found the one > fixed by patches 1-3. I used an LLM-based assistant to write the patches > and descriptions, and reviewed its work. Thanks! Patches 1-3 look good. I'm less sure about patches 4-5, since they go through some trouble to work around (some implementations of) poly1305_blocks() and chacha_crypt_arch() not taking size_t. Wouldn't it make sense to convert those to size_t at the same time? - Eric