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 D11A219FA93; Tue, 20 Aug 2024 15:26:35 +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=1724167596; cv=none; b=A8NfyzQcQ89CCTmvyhUTjGOzV48HBHvezjHkcxZSQPp+GtS7W9ExjX27lmzTsBe4hSLwHreB9ORW3+bkXPUTAV6GydXLwCRGsm6b4PwNmsz62aq3z4nh7esgTkGMmKVPfiIXs0l9g4tG6QnImQpUFhXnYdJjijAP1Mt70mpGxH4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724167596; c=relaxed/simple; bh=cul7AYUW/oUYJetixYQFOVkrNIZzj7nX7ZdNR4EJkYY=; h=Mime-Version:Content-Type:Date:Message-Id:From:To:Cc:Subject: References:In-Reply-To; b=JDmV8VyKaR2F4n0MRkPpM2lOqxbzQ4tMnzAy7z9ELjjixds9k2wvXvhG4MjgnP8LL7POX0FnxKZZ52f5JaudhfyFJ9RsqmMUu1QCEnBbDn/kVo5PN0nKmW+zcvw3g0y3TSEhjKcTxABmwM6IUPLYMsTQqQKBIB5krFwX8gnT1H8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YYij2JgH; 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="YYij2JgH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C51E3C4AF14; Tue, 20 Aug 2024 15:26:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724167595; bh=cul7AYUW/oUYJetixYQFOVkrNIZzj7nX7ZdNR4EJkYY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YYij2JgHvU1AVhaIiSFSmqh3C4f+ic8eJASZifn6Evsee/JMB21kiEgUtpOIBAzfw WhPHhWbdxcAJ3GX75aIWxGKoIE+TbIbkElRQxkSiCM1gSh7PD6MUNxSUUoVKCpdCo5 Br49eRY1Fh7j8jsrdqPjohHKrKIQUkf6RV1BkZp3Zhod/8qnYQgViR4l08DXR6aSmW DulskVJSqnfDMUzs1+E910tAcZopB11i46RMlqd/GfDzeV8Bwbz6KJUBtopdAKLoXo UJG9b6LftIfnK02/OMGuvfBF4uYp8xc4JKrLL2vskwO7qu1TbpCs1VTOoV0Mv/xjHN vN7mHGvix1P4A== Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 20 Aug 2024 18:26:31 +0300 Message-Id: From: "Jarkko Sakkinen" To: "Matthew Garrett" Cc: "Andrew Cooper" , "Thomas Gleixner" , "Daniel P. Smith" , "Eric W. Biederman" , "Eric Biggers" , "Ross Philipson" , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v9 06/19] x86: Add early SHA-1 support for Secure Launch early measurements X-Mailer: aerc 0.17.0 References: <20240531010331.134441-1-ross.philipson@oracle.com> <20240531010331.134441-7-ross.philipson@oracle.com> <20240531021656.GA1502@sol.localdomain> <874jaegk8i.fsf@email.froward.int.ebiederm.org> <5b1ce8d3-516d-4dfd-a976-38e5cee1ef4e@apertussolutions.com> <87ttflli09.ffs@tglx> <550d15cd-5c48-4c20-92c2-f09a7e30adc9@citrix.com> In-Reply-To: On Mon Aug 19, 2024 at 9:24 PM EEST, Matthew Garrett wrote: > On Mon, Aug 19, 2024 at 09:05:47PM +0300, Jarkko Sakkinen wrote: > > On Fri Aug 16, 2024 at 9:41 PM EEST, Matthew Garrett wrote: > > > On Fri, Aug 16, 2024 at 02:22:04PM +0300, Jarkko Sakkinen wrote: > > > > > > > For (any) non-legacy features we can choose, which choices we choos= e to > > > > support, and which we do not. This is not an oppositive view just s= aying > > > > how it is, and platforms set of choices is not a selling argument. > > > > > > NIST still permits the use of SHA-1 until 2030, and the most signific= ant=20 > > > demonstrated weaknesses in it don't seem applicable to the use case= =20 > > > here. We certainly shouldn't encourage any new uses of it, and anyone= =20 > > > who's able to use SHA-2 should be doing that instead, but it feels li= ke=20 > > > people are arguing about not supporting hardware that exists in the r= eal=20 > > > world for vibes reasons rather than it being a realistically attackab= le=20 > > > weakness (and if we really *are* that concerned about SHA-1, why are = we=20 > > > still supporting TPM 1.2 at all?) > >=20 > > We are life-supporting TPM 1.2 as long as necessary but neither the > > support is extended nor new features will gain TPM 1.2 support. So > > that is at least my policy for that feature. > > But the fact that we support it and provide no warning labels is a=20 > pretty clear indication that we're not actively trying to prevent people= =20 > from using SHA-1 in the general case. Why is this a different case?=20 > Failing to support it actually opens an entire separate set of footgun=20 > opportunities in terms of the SHA-1 banks now being out of sync with the= =20 > SHA-2 ones, so either way we're leaving people open to making poor=20 > choices. This is a fair and enclosing argument. I get where you are coming from now. Please as material for the commit message. BR, Jarkko