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 F16FA37C0EC; Thu, 8 Oct 2026 20:15:52 +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=1791490554; cv=none; b=LrT6eBdrJRam4yW1UNNj1yQxretwk+CNPKMuXWjhelQrVDJYg4ES9DEbkfl58jJ5uIjXDO1H7G9A8+9V7oTRNlQcctn+rLGFQd/3zTtDLoHiexgD36PFtMlC3dJSK9nq1TLGG1w/AY5t4L5gDW8iZJL4ogCSkBhxUz05P2MRyGk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791490554; c=relaxed/simple; bh=bXxQnv/foLDDmbSk93eHOxtiE+zfvSULWr5EfJ1SzfQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Q3qIQhFUDjUrh53DbnoJRS/6+1QgGdDkgiSuFrBk5NZ5PXn2Hk3+VxAgwaSKgyr+YMFSVfC2mSvHrVAtucmNSRXg7CZXmgcMeG277XBG21265S7CEpUxPu4ixc9zSzU1QwkDdBtmDFhSoHtwKLXrb9J3PRqwKLLF9OtMmL1N3UM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oqrZnUcl; 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="oqrZnUcl" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 312D01F000FF; Thu, 8 Oct 2026 20:15:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791490552; bh=4iWC4txC/hGiO+U81FY2Efqs3MRlpdhy7EvICtlaB6c=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=oqrZnUclFhqCNnr7LY2DFjptLhHSAeSnsDTIvc6sZnA2/3R7kIwFLT+8lSRxkv1za uhi3C0uIQVDxuy0XtWbsanSXMyHjiYWB7YJAeOTWjbM4Vd0sX4SeGKiDUup8Lp5Occ kNtK6T4Gg2B8Xcb6Xw5P7cXBthJeYPX0WPX3niJgWGYH23RhRXK6KuIu8T71Ei2nqY gpprUmIm5EkQLb0M/ccaMIHCKdSmbuCe4GIjf96Ocd3VyvePcbl0R6RDbzZLc0h3RN CxBCKllixOnq+GaKxeVl9iWDKe2j774G95JD9LQPZvLjuzkohID8DymdJ97I62uDpf mUdylBUj3o4mw== Date: Thu, 8 Oct 2026 23:15:49 +0300 From: Jarkko Sakkinen To: Andrew Halaney 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: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Oct 08, 2026 at 01:41:55PM -0500, Andrew Halaney wrote: > On Thu, Oct 08, 2026 at 08:33:45PM +0300, Jarkko Sakkinen wrote: > > On Wed, Oct 07, 2026 at 10:30:14AM -0500, Andrew Halaney wrote: > > > 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 :) > > > > Understandable :-) > > > > > > > > Are we happy with these to get picked up? > > > > Can you just do a resend that applies on top of latest mainline > > or my tree? I.e. b4 shazam was not happy about this. > > > > Full log: > > > > $ b4 shazam https://lore.kernel.org/keyrings/20260914-ajhalaney-dmverity-key-identifier-v1-2-01922dc1366a@amutable.com/ > > Grabbing thread from lore.kernel.org/all/20260914-ajhalaney-dmverity-key-identifier-v1-2-01922dc1366a@amutable.com/t.mbox.gz > > > > Breaking thread to remove parents of 20260914-ajhalaney-dmverity-key-identifier-v1-0-01922dc1366a@amutable.com > > Checking for newer revisions > > Grabbing search results from lore.kernel.org > > Analyzing 10 messages in the thread > > Analyzing 0 code-review messages > > Checking attestation on all messages, may take a moment... > > --- > > ✗ [PATCH 1/3] keys: add KEY_SPEC_DM_VERITY_KEYRING > > + Reviewed-by: Jarkko Sakkinen (✓ DKIM/kernel.org) > > + Reviewed-by: Christian Brauner (Amutable) (✓ DKIM/kernel.org) > > ✗ [PATCH 2/3] keys: add KEY_SPEC_FS_VERITY_KEYRING > > + Reviewed-by: Christian Brauner (Amutable) (✓ DKIM/kernel.org) > > ✗ [PATCH 3/3] Documentation: keys: document IDs added since KEY_SPEC_REQKEY_AUTH_KEY > > + Reviewed-by: Christian Brauner (Amutable) (✓ DKIM/kernel.org) > > --- > > ✗ BADSIG: DKIM/amutable-com.20251104.gappssmtp.com > > --- > > Total patches: 3 > > --- > > Base: base-commit 1a1de54f7369cd2b5bac0f265910e60ad3a6b4c3 not known, ignoring > > Applying: keys: add KEY_SPEC_DM_VERITY_KEYRING > > Patch failed at 0001 keys: add KEY_SPEC_DM_VERITY_KEYRING > > error: patch failed: include/linux/key.h:441 > > error: include/linux/key.h: patch does not apply > > error: patch failed: include/uapi/linux/keyctl.h:25 > > error: include/uapi/linux/keyctl.h: patch does not apply > > error: patch failed: security/keys/process_keys.c:25 > > error: security/keys/process_keys.c: patch does not apply > > hint: Use 'git am --show-current-patch=diff' to see the failed patch > > hint: When you have resolved this problem, run "git am --continue". > > hint: If you prefer to skip this patch, run "git am --skip" instead. > > hint: To restore the original branch and stop patching, run "git am --abort". > > hint: Disable this message with "git config advice.mergeConflict false" > > Egh, sorry I was on linux-next. I'm also realizing that the > KEY_SPEC_BPF_KEYRING bit this sort of depends on is only in bpf-next > (i.e. 264d8fd2794f ("bpf, keys: Add a bpf keyring for program signature validation")). > Otherwise as is this conflicts on mainline and we'd just have to skip > the -9 the bpf keyring is using at the moment. > > Should I just base on bpf-next that and send thru there instead? I can't recall > how kernel maintainers typically handle this other than cutting a stable > branch that both subsystems pull from, etc. I don't mind if you would take care of the PR through that route. You can add my r-by to each patch. > > Thanks, > Andrew Br, Jarkko