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Donenfeld" , Herbert Xu , linuxppc-dev@lists.ozlabs.org, Michael Ellerman , Madhavan Srinivasan , Nicholas Piggin , Christophe Leroy Subject: Re: [PATCH v2] lib/crypto: powerpc/md5: Drop powerpc optimized MD5 code Message-ID: <20260509184144.GB11883@quark> References: <20260506030005.9698-1-ebiggers@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260506030005.9698-1-ebiggers@kernel.org> On Tue, May 05, 2026 at 08:00:05PM -0700, Eric Biggers wrote: > MD5 is obsolete, is vulnerable to collision attacks, and is being > replaced by SHA-256 in new systems. It doesn't make sense to continue > to maintain architecture-optimized implementations of MD5. Effort > should be spent on modern algorithms. > > Indeed, architecture-optimized MD5 code remains only for powerpc. It > was already removed from mips and sparc, and it never existed for any > other architecture (e.g. x86, arm, or arm64) in the first place. > Earlier the decision was made to keep the powerpc MD5 code for a while > anyway because of someone using it via AF_ALG via libkcapi-hasher > (https://lore.kernel.org/r/f0d771d5-ed70-444c-957a-ad4c16f6c115@csgroup.eu/) > > However, with AF_ALG itself now being on its way out due to its > continuous stream of security vulnerabilities > (https://lore.kernel.org/r/20260430011544.31823-1-ebiggers@kernel.org/), > it's also time to be a bit more forceful with nudging people towards > userspace crypto code. It's always been the better solution anyway, and > it's much more efficient if properly optimized code is used. > > Note that the md5-asm.S file contains no privileged instructions and > could be run in userspace just fine. > > Thus, we now have two factors going against keeping the powerpc MD5 > code. Different people might weigh these two factors differently, but I > think the two of them together make the removal the clear choice. > > Let's remove it. > > Acked-by: Christophe Leroy (CS GROUP) > Acked-by: Ard Biesheuvel > Signed-off-by: Eric Biggers > --- > > This patch is intended to be taken via libcrypto-next Applied to https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=libcrypto-next - Eric