From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 EA95E4084C; Thu, 15 Aug 2024 19:10:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723749018; cv=none; b=aY9WjHVHuX52PeaHme+2odiYNxyO1ma5OMVKC4Nkc1rxZxZtg1PUopXnSa30xUv+gyFvarASFium6tx1D3bGyaUBLRAFXpzFJkr70bzsPj/oI4bgNFoIASSsY9oocbMp/YKQ4+mMALZISZCWLnYeSAviRvgE4T2yxzGrXF1b5Y8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723749018; c=relaxed/simple; bh=qX4J3Xd64CEwbRGOxae+jQ1qggxaa6N08g0sY0Yr4kk=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=E85Y8fHH6u4Vz/lqCrmxRnoT9rrNYRJqlKHPVj5yCw+mMh3HHWhLbAlYhGKi9Rw7eP40bMcwk+OEAd1jqZ78CbcQIpLOdl8/tvIuiv+tZu/WRr8wnDRYGHPSu9KF8zCsEQc+JliKvJJCbA3RUkKd1Wotdpu0Mubo+Ua/kjZdpc0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=tXHVRT29; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=cAIOFZaz; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="tXHVRT29"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="cAIOFZaz" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1723749014; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fZTVvaO2p2W+P+UPnKNV9BKWDUfkQHL/Xf0aN8/w5q0=; b=tXHVRT29inPW/Cw8vHHs1o14Q4Yg3be6qe6cDE1L2kjUo1Ou+VJWbihHot0QdYTT2XmfNq Q7QHsyjgqoB5Q42qu0yDhBmmkonyK9Cl6Ff4CsaEjhOwJ86AXJXwKqyY5kAg9g14zXrdxO ax7P6WZqn9oe9FXaY5ioB5ukKN9HGo/U2D2wj5FHKutnuWinDt8ZRCGFBmxRLt3hc8qnfc sJvVZE7ClLcjgLf59JVQy2y7fu6zGzKEnF1gvED+dsVLlyDPjYBCOWSqXX1AJYZeW0plRT 84C/Hq8k3joLra6RWJ+SAEv1oMijRvkMW5KQVtHRF8nD6KNa++f8NFzn4DeM4w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1723749014; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fZTVvaO2p2W+P+UPnKNV9BKWDUfkQHL/Xf0aN8/w5q0=; b=cAIOFZazMeEHCSiUEc0/bZDaCxz0Zt0Bdo6zTqNdOOXhSC3N+b2lASD42ZXOG8ROfzkNKS ENdJDWGyB1XUvtDQ== To: "Daniel P. Smith" , "Eric W. Biederman" , Eric Biggers Cc: Ross Philipson , linux-kernel@vger.kernel.org, x86@kernel.org, linux-integrity@vger.kernel.org, linux-doc@vger.kernel.org, linux-crypto@vger.kernel.org, kexec@lists.infradead.org, linux-efi@vger.kernel.org, iommu@lists.linux-foundation.org, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, dave.hansen@linux.intel.com, ardb@kernel.org, mjg59@srcf.ucam.org, James.Bottomley@hansenpartnership.com, peterhuewe@gmx.de, jarkko@kernel.org, jgg@ziepe.ca, luto@amacapital.net, nivedita@alum.mit.edu, herbert@gondor.apana.org.au, davem@davemloft.net, corbet@lwn.net, dwmw2@infradead.org, baolu.lu@linux.intel.com, kanth.ghatraju@oracle.com, andrew.cooper3@citrix.com, trenchboot-devel@googlegroups.com Subject: Re: [PATCH v9 06/19] x86: Add early SHA-1 support for Secure Launch early measurements In-Reply-To: <5b1ce8d3-516d-4dfd-a976-38e5cee1ef4e@apertussolutions.com> 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> Date: Thu, 15 Aug 2024 21:10:14 +0200 Message-ID: <87ttflli09.ffs@tglx> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Thu, Aug 15 2024 at 13:38, Daniel P. Smith wrote: > On 5/31/24 09:54, Eric W. Biederman wrote: >> Eric Biggers writes: >>> That paragraph is also phrased as a hypothetical, "Even if we'd prefer to use >>> SHA-256-only". That implies that you do not, in fact, prefer SHA-256 only. Is >>> that the case? Sure, maybe there are situations where you *have* to use SHA-1, >>> but why would you not at least *prefer* SHA-256? >> >> Yes. Please prefer to use SHA-256. >> >> Have you considered implementing I think it is SHA1-DC (as git has) that >> is compatible with SHA1 but blocks the known class of attacks where >> sha1 is actively broken at this point? > > We are using the kernel's implementation, addressing what the kernel > provides is beyond our efforts. Perhaps someone who is interested in > improving the kernel's SHA1 could submit a patch implementing/replacing > it with SHA1-DC, as I am sure the maintainers would welcome the help. Well, someone who is interested to get his "secure" code merged should have a vested interested to have a non-broken SHA1 implementation if there is a sensible requirement to use SHA1 in that new "secure" code, no? Just for the record. The related maintainers can rightfully decide to reject known broken "secure" code on a purely technical argument. Thanks, tglx