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 0AFA9383; Wed, 6 Nov 2024 23:40:35 +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=1730936436; cv=none; b=fEVQINmD+6aFg5ogPJ1E+Knt40U0PRdpxHzYsPlh2VpGmrPFitFx9m7eT6ZihLSKb7uhgod5hHAibAVTyAJqxB4VRBxSEnNutGaRUirpnzQ9Ff/z9WGBkekEpir9w/AqLPSpJldsKaAOVx6K9yqknUsdOdaH8d+qdx3ppJiW+08= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730936436; c=relaxed/simple; bh=3QtCqY2ZAUWBCu848of9UUBkU/Uq+o/yLi4fFYFPYRE=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=m4AOglAEvK99aLCioHLOYhsjztKudEpdZ+ZyHT4D0qDryho1RqsYB8yd//du1X2F0tTI25J0dAIDUH7sVXX+07JFPHdDylOJV8qnpKCkVd9PM8TgiPFlhuYMoF7af+r5X9qLEq8JUmW4fUjdbLimEOws+foyX8yyTZCrpeTUR1I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=njxY4Y7X; 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="njxY4Y7X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 224B7C4CEC6; Wed, 6 Nov 2024 23:40:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730936435; bh=3QtCqY2ZAUWBCu848of9UUBkU/Uq+o/yLi4fFYFPYRE=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=njxY4Y7XrwLPxoRFD3I+WMLmAY9ydcRiOD35mnYWpeMTNPL8xeNRTKvcLDIJ0Erph vsXIdfrlgFatYTXagniaxq5fVf0Y1LlZalrKgEck0+Z3lYHe2QkXvNrI0iSFwjXRmq rx44mpxL+0qjU+xuQ4lcsUOcC3MwT0O/j/SvsEe1nchogv1FIq5vrXcOhrIJTJDXIG t4ZzY4jTzP5AWdElK77BOGsCP6FH6h0XdRHHgz5IDKB8VLNnUf4N2d7rVD4UqC8Ni5 JXxmiZJzFL49oroHicWAVSRcasYbUk8knNinN5dvHqOdL7XYm9gf9eZ5l+LHxB2OI3 GQ+aXso88Y26A== Precedence: bulk X-Mailing-List: linux-kernel@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: Thu, 07 Nov 2024 01:40:31 +0200 Message-Id: Cc: , , "Paul Moore" , , Subject: Re: [RFC PATCH] tpm: Allow the TPM2 pcr_extend HMAC capability to be disabled on boot From: "Jarkko Sakkinen" To: "Jarkko Sakkinen" , "James Bottomley" , "Mimi Zohar" , X-Mailer: aerc 0.18.2 References: <20241015193916.59964-1-zohar@linux.ibm.com> <321b247dcfaba5d9691919eec8476b3c6fc7875d.camel@HansenPartnership.com> In-Reply-To: On Thu Nov 7, 2024 at 1:22 AM EET, Jarkko Sakkinen wrote: > > I'm a bit confused here. It's TPM2_PCR_Extend we have the trouble with > > (as Mimi says in her email that you quoted) not TPM2_GetRandom. > > > > The random number generator reseed occurs in a kernel thread that fires > > about once a minute, so it doesn't show up in really any of the boot > > timings. Plus even with sessions added, what there now isn't a > > significant overhead even to the running kernel given it's asynchronous > > and called infrequently. > > Ah, right then we need the boot flag, and my earlier comments to the > parameter apply. I've never used IMA so I don't actually even know in > detail how it is using TPM. > > Now that I did some seek I mixed this up with the report: > > https://chaos.social/@gromit/113345582873908273 > > Anyway concerning this issue and patch, my earlier comments still apply. Makes me wonder tho why do we then export tpm_get_random() in the first place? HWRNG does not needed that export, and the code does not have any of the mentioned features. BR, Jarkko