From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f177.google.com (mail-yw1-f177.google.com [209.85.128.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A9BDE443307 for ; Wed, 7 Oct 2026 15:30:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791387025; cv=none; b=qW59TW0S5VeH/FRv6hITSCP0k/qYDhRjkDKTv3cOkcPBEC90ciO6vWb/acwBRGa8vqeNavAvDh7BYbPCymcMa1fVU6LGS8z/sF3Npu5vVnxOwRSM9LR+uQ7Zr88JyZIAbj69GyuZKdTuIuzaHBDPy3H3Jafopx/QZEtUkHQFSxE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791387025; c=relaxed/simple; bh=5kpnZ69rpIeJK7I/vVJI1/Sd58TTWJsQUlkCNqKOhyI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Y1REMHOuREF3XbwbNWEHOMvLa8VNl1XrC3E6+jBXkbF6RqSRUxBazVGlSIY9wc7ODFuHp2so6lF9QmUsKg1Qq6GiewVhOOyTqYHL5UFkR5euHQUQd5OFPQp6Hgq0zhjA8vEg9j83tTA3EMEYtGVI2vL3wRzFTX/1YP4hoPALh7o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=amutable.com; spf=pass smtp.mailfrom=amutable.com; dkim=pass (2048-bit key) header.d=amutable-com.20251104.gappssmtp.com header.i=@amutable-com.20251104.gappssmtp.com header.b=YnRLPHMi; arc=none smtp.client-ip=209.85.128.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=amutable.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amutable.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amutable-com.20251104.gappssmtp.com header.i=@amutable-com.20251104.gappssmtp.com header.b="YnRLPHMi" Received: by mail-yw1-f177.google.com with SMTP id 00721157ae682-8b056d58f2aso14935117b3.2 for ; Wed, 07 Oct 2026 08:30:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amutable-com.20251104.gappssmtp.com; s=20251104; t=1791387019; x=1791991819; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=fxMsGMJoi15xhCerKdZHKbDFnpM/+Dr7cx060hZaVDo=; b=YnRLPHMiCGr5unS/o2c2EHvTVZtDLbNOMEOwpd1emzZ9X7nI/Gocgnbxthvcq+VLnu m48QAP1/vPGB9oDTrrKC7Bo+unLlCLwhVA0saPLhPW1jvSP4ewxx2JLky82lJE975xJj SCKdzRZDTnb2ISXI9sBkydjuiJhmpwYY1hI3Ey7dgIVXcoRJN+4tgwR3HB0ggPXc4MOa 9NlCL+H8UUddsFhIjUecIk0R+RAZ8hkEGx4AbJspsUeCI08jOlOBawdMppoeN/t5r5Ur 3RGfeYp0YyHPy74bXPTdoANsMdK8g5jDlk5C8I3+7FptOoV35TKSO8aDhYI4BtN+aCJg 67Pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791387019; x=1791991819; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=fxMsGMJoi15xhCerKdZHKbDFnpM/+Dr7cx060hZaVDo=; b=L1GqqjZSDk0xyBPQ86R+3+pq+2YL2tPy4kgIsNPpTRzAznDNSb02i3Dz+BwrNC06LK nvwkczx/Rcjw/C/YakIkWX/XhWuZ8SjbOwSzDJg7hr78u+0oHeOcbBwFBcM+TyLYi4N5 xPZhL77YcR7Z12ObRNtazXtY+vjDr4Sb8Ngpl7B98W6NmuRc6EEqufrRm5xjfe23B2+k V+thkc/KGkHuhBn6D+nHMPlUa1TeUsKGh6UhhWMMnFBJuUo71zVw+Qv/MtItGHEhwg91 7HfYmLwAKJ6slSmwxQN44u9TuCkMKsfjwasMD+AjbUiCiE3WBHo4yOfGa+oNKSL6+VuD r9qg== X-Forwarded-Encrypted: i=1; AKwUvBy85k5fKLRxFaVKsRmYq3gJmHqD9xyJgfXrRui8+Y2EcCTq0sWjxla7EOg193vYX+rwJMs=@vger.kernel.org X-Gm-Message-State: AFq9FYJ2iwUZsYEOX68+HDcowoXa6O/oQ5wlG55yVhF8df2H/P3bCLeL 7Q8iD5/KNi/3wj5eK3a7SDxxErYFs8beWhwigmOiGX/r9VzyQSFVfk46eXQpF8ADXDYR X-Gm-Gg: AYBFou24rkHuQ0+6ZFoZnbgVaX4cuioEV+r26xi9jZCctINxnJ9sAzzSJjlaBMIAiUQ PLnNZ1+lZa4jZK5lOe6rHMkuY04zmnihzbZUtWT+wGUNLirxoqSckzn86c3DYjl4yoKg/F+DiG3 icMw6XKDEv0ECsTMinpx5MOiSet4RRLrC8Iq/AaoxXNqNrCI4bgML0Wx7QknzDvnGy6UzNHQabR t5KPBOD8aM5NCuh0CRCDCgOjMxxzq6AJaI8cS56irFj90cvTXDJ0vVOHoKIxNNElZoW1EoSCcpS aQEyztstb5f8gEIEEMSJop+Ak51P46GCfXj1NEYCmc5szs2g/Yurv4q7j+xMjwmffuLSWrhLnAs DDJ0Ps0cW840yNIOAWc8CSClWNQNqOB4FAEql9X8xtcaSU73smiJSogDwP57Np0p/rD0EtfTgS1 aKmjClY6o9BDPmDuWGuSLZR3YIbkIP9VNZ7cLDaqIOgqcnTZ9Rl0qSSdcTTAMUxtZhdSK8vBrXW JlHkko/uw6j3Oao1/2IjbAmQlKl+EGDJqFMd9ncv7o= X-Received: by 2002:a05:690c:6b01:b0:873:5bb2:6c3d with SMTP id 00721157ae682-8b05b14e894mr18727417b3.68.1791387018749; Wed, 07 Oct 2026 08:30:18 -0700 (PDT) Received: from toolbx (104-53-165-62.lightspeed.stlsmo.sbcglobal.net. [104.53.165.62]) by smtp.gmail.com with ESMTPSA id 00721157ae682-8b05a9b8806sm9897427b3.1.2026.10.07.08.30.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Oct 2026 08:30:18 -0700 (PDT) Date: Wed, 7 Oct 2026 10:30:14 -0500 From: Andrew Halaney To: Jarkko Sakkinen Cc: David Howells , Alasdair Kergon , Mike Snitzer , Mikulas Patocka , Benjamin Marzinski , Paul Moore , James Morris , "Serge E. Hallyn" , Eric Biggers , "Theodore Y. Ts'o" , Jonathan Corbet , Shuah Khan , Randy Dunlap , dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, bpf@vger.kernel.org, fsverity@lists.linux.dev, linux-doc@vger.kernel.org, "Christian Brauner (Amutable)" Subject: Re: [PATCH 1/3] keys: add KEY_SPEC_DM_VERITY_KEYRING Message-ID: References: <20260914-ajhalaney-dmverity-key-identifier-v1-0-01922dc1366a@amutable.com> <20260914-ajhalaney-dmverity-key-identifier-v1-1-01922dc1366a@amutable.com> <715249.1789718726@warthog.procyon.org.uk> Precedence: bulk X-Mailing-List: bpf@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: On Fri, Sep 25, 2026 at 11:39:28AM +0300, Jarkko Sakkinen wrote: > On Fri, Sep 18, 2026 at 02:59:49PM -0500, Andrew Halaney wrote: > > On Fri, Sep 18, 2026 at 09:05:26AM +0100, David Howells wrote: > > > Jarkko Sakkinen wrote: > > > > > > > This is great for discussion but what we want for the commit message > > > > is just motivation and resolution. > > > > > > Actually, I think it's useful that Andrew wrote up the issues in the commit > > > message - and I think it shows part of the motivation. The 'writing a fake > > > /proc/keys line in the description' is something I hadn't considered. > > > > I'll defer to what you all want in the message here, I found it valuable > > but I trend on the side of overly verbose admittedly! > > > > > > > > > I don't think we need all this just to say that /proc/keys in a racy > > > > query mechanism for production, which is an issue for dm-verity, given > > > > that nothing else is available. > > > > > > I think at some point, we will need a system call to search all for all > > > accessible keys matching certain criteria by actually walking the key > > > database. The problem there is that there may be multiple hits, so we may > > > need something like: > > > > > > int count = find_key(key_serial_t start_id, > > > const char *type, const char *desc_prefix, > > > key_serial_t *results, size_t results_size, > > > unsigned int flags); > > > > > > Allowing you to do: > > > > > > key_serial_t dm_key; > > > int n = find_key(0, "keyring", ".dm_verity", &dm_key, 1, > > > FIND_KEY_EXACT_DESC); > > > > > > This wouldn't be as fast as a direct lookup since it would have to walk the > > > key tree, doing name comparisons and perm checks on each key of the type. > > > > > > > And secondly special keys are meant for implicit keyrings so isn't > > > > that all there's to it? > > > > > > I have no particular objection to setting aside a block of negative key IDs > > > for special keyrings that need to be accessed a lot - though I would make > > > common reg/unreg functions that take the ID to be registered and, say, set the > > > block at -257..-512. Moving the BFP keyring to -257 and DM to -258. > > > > To be clear are you suggesting I do that for v2 here? Happy to make the > > change and add some reuse to the registration functions, etc. I'm > > guessing its fine to change the bpf id since its still only in -next? > > > > The only awkward bit with making that more generic is that dm-verity > > isn't __ro_after_init since its coming from a module possibly, and > > because of the module usage I also protected it with a spinlock in case > > someone's accessing it while you unload the module. Could just use one > > spinlock for the whole generic array, and drop the __ro_after_init I > > suppose. > > > > Let me know if I'm not following properly! > > I just read David's response and I think he made fair arguments, > and patches look fine to me. > > David, did you have anything? I could pick these. > > Reviewed-by: Jarkko Sakkinen > Gentle ping :) Are we happy with these to get picked up? Thanks, Andrew