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 D0B9349481A; Thu, 10 Sep 2026 14:14:58 +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=1789049699; cv=none; b=GbzLqfNXAIemeR1zPxrX1C3NZMqSqTjlf5+ovb9IovV5tWe7kBNBhA2W2kMdkwWJdo7BY/F8EksEhLU8p6MrmKtZhH4OO+817cK/mu18S/qon2Xw8T74aVgibCxn4shAYRGtYwfZAH16Z0zG1To99ygOVvZog+Upsa0uhov0bvQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789049699; c=relaxed/simple; bh=vZb+To3dn7nxMqAF+xniM1hj6OZWHwB4F6mWcKx9Qw8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hreJcXSvc/iUepvLXXcmhwDBH+vJg5WWyKm50zivo0BVtA34p3ElEyvMqI/nfsy/QxcE63XkTgu4JBFKGbD+XALSSGD9zTXBqjTEC95rF7tSiFekiRAtgUwaCrMmaE3cxwVJRcpq+/LG+Blori7tQQTLc8lgRDFxoBHh14K/x1c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=niPBdpix; 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="niPBdpix" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C0281F000FF; Thu, 10 Sep 2026 14:14:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789049698; bh=aaH94r2pnTGyhZ2s2DCtMt9jAIlcwDGgoPae43u3KbI=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=niPBdpixKg9E9hqQj+GTyb42eVqDLarLNBGOOajS0BYsqMl6xxrV2LQ5OtyQkYEEY 4Ta6rgMg8Ik1nw2cS2V9VsO7QgTwjlx1i4ayNDlfGFs/bNK3XrVMHw3tWLqgN5Z6CZ Ppw5qTar0i9NxUqC6AfaeVbUB3jrkFhpWKisjhC4wLIWyVIrh64Q45UnHydlWziIuF vtoq/d6Dc85jiyZCOPKYlntu0vzvT2gHx5+AdagFeOKbE7M1eGVJ8OaE+8h78vy/J6 SPMM4iZHxysLD5C06I907FHrcU+orF4ce+WOOTLOEU2biAyop0fu6zOGBmYejd3o+C 6U0FlgGyyTocw== Date: Thu, 10 Sep 2026 09:14:56 -0500 From: Eric Biggers To: Thomas Huth Cc: Joachim Vandersmissen , "David S. Miller" , Maxime Coquelin , Alexandre Torgue , linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Herbert Xu Subject: Re: [PATCH] crypto: testmgr - block Crypto API xxhash64 in FIPS mode Message-ID: <20260910141456.GA1936@quark> References: <20260303060509.246038-1-git@jvdsn.com> <64592fee-1956-4a70-a751-9ac3335cfc27@jvdsn.com> <9926908a-5f08-43ba-99dd-b83c7067d52b@redhat.com> <83d09aa1-729a-47a2-a8e9-381c74e92f42@jvdsn.com> <48f12b65-428d-4809-9735-18876b09e759@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <48f12b65-428d-4809-9735-18876b09e759@redhat.com> On Thu, Sep 10, 2026 at 10:57:32AM +0200, Thomas Huth wrote: > On 10/09/2026 05.24, Joachim Vandersmissen wrote: > > Hi Thomas, > > > > On 9/9/26 9:36 AM, Thomas Huth wrote: > > > On 15/03/2026 01.43, Joachim Vandersmissen wrote: > > > > Hi Herbert, > > > > > > > > I don't think this one can be applied yet since dm-integrity > > > > still uses xxhash64 through the crypto API. This would break > > > > fips=1 systems that use it. > > > > > > Out of curiosity: Wouldn't such a system be FIPS-incompliant anyway? > > > If xxhash64 isn't FIPS-compliant, nobody should use it for > > > dm-integrity there, right? So I doubt that there are any systems out > > > there that use fips=1 and use xxhash64 at the same time? > > > > There is a risk that users may not know that xxhash64 is not FIPS > > compliant and would still use it. Especially considering it was marked > > as "fips_allowed = 1" for a while. > > So isn't that a very bad situation? They think they are FIPS compliant, but > actually they are not since they use an unapproved algorithm by accident. > Maybe it would be better to include this patch so that they are aware of the > mistake? If there is really somebody running into this issue, they could > boot once with fips=0, fix their system, reboot again with fips=1 and > finally be really compliant. Sounds like the better solution to me. WDYT? As described in the dm-integrity documentation, dm-integrity supports non-cryptographic checksums for protection from accidental corruption. That use case is no different from any other use case of a checksum. It's also no different from using crc32 or crc32c, which similarly have fips_allowed=1 and this patch completely ignores. The solution is not banning checksums or making any other code change, but rather just doing what it seems everyone has already been doing: documenting in their FIPS security policy that checksums are only for use cases that are not "security functions". - Eric