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 C10343290BA; Fri, 21 Aug 2026 19:36:38 +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=1787340999; cv=none; b=UJ1HwhGmXzcAgtmLNT4g86zVghem75h3U28llgupqFQ9QHQq+4oagC1/I3/c1sI36kS/8jxYYBhE5VCdOIxKqpkuo5LWGij/lBd6ePKwS+6yz1H+0POcuL5PrOQitPx9sZzdT70oh/8Jov0Yu3hhYPCVO4pRDivZo3gTjmQdNfc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787340999; c=relaxed/simple; bh=cUsq+Jmf8apQl1NBeoDRm+LBp1wVZs2qURQY2o9c91U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QFKNS8naZ7HtSweqOpZ+FCwJFJZxU6O/qvVLfcV+SQklGZlFqm/QNOXBWHv4+pU/h4oNb7lSgvzSPoLgZ2TOc9cOBni6DyoQZDrZxgAEC8RxLOSphXQia5qIsrZYbR86T5yFTMyCcROep7gz1JQ5WhBy3n0eNd1JyrHDKjX4qlM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bG4wbAk+; 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="bG4wbAk+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FDBD1F000E9; Fri, 21 Aug 2026 19:36:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787340998; bh=MTBVTy5LK2ZrdXijoZ7hCKmeHVYe2AOnTQW1ot5ORYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=bG4wbAk+jA0qzDbtfwGpqVh5IS9ShIc//CTT8Z9NyZWONqpwJ7iVEP6gR0heAy1Qb r/2Wzh+DtGdPP68FiTaZdwzlppJ2uoeFDY7czLnObUuHfRY4MAP0se9CmqS+SZuNzv SZadQbrbQDaPx+HlVaqaSdVl3m53GFWLxBflmDI7Dd+yRF0PetD4g8ICGPUQ9FDtW6 3uKzsCvDwmLL6vT8HaCiph0gQGEXd65VdFZBp09bUxf15D4iYcO5nWw02btcjLm43i Rvgrq2t5+VRbEKm+3KOZsD1s+A+RgCONiusKZRyT/PKGwXOH6nCZg7S3QewW3W1x3O 4HOxpT+2D/hkw== Date: Fri, 21 Aug 2026 19:36:36 +0000 From: Eric Biggers To: Thomas Huth Cc: Ilya Dryomov , Alex Markuze , Viacheslav Dubeyko , Viacheslav Dubeyko , ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] libceph: Re-establish the FIPS keylength check in the Ceph code Message-ID: <20260821193636.GB3141245@google.com> References: <20260821144323.776371-1-thuth@redhat.com> <20260821175312.GA3141245@google.com> Precedence: bulk X-Mailing-List: ceph-devel@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: <20260821175312.GA3141245@google.com> On Fri, Aug 21, 2026 at 05:53:15PM +0000, Eric Biggers wrote: > Do Ceph session keys shorter than 128 bits even actually occur in > practice? It seems that the Ceph authenticated modes support only > AES-based cipher suites, where the minimum valid session key length is > 128 bits. > > I wonder if the client should just reject session_key_len < 16 > regardless of fips_enabled. It looks like this is theoretically possible only when CEPH_AUTH_CEPHX is being used but the session key uses CEPH_CRYPTO_NONE, which seems insecure and contradictory, and likely not ever used by the server. I suspect the ceph client should just reject that combination outright (and also session_key_len < 16 as defense-in-depth). It is up to the ceph folks who are the experts here, but if there are unnecessary footguns like this, they should just be fixed for everyone. - Eric