Re: [PATCH v8 4/4] kexec, KEYS, s390: Make use of built-in and secondary keyring for signature verification

["Michal Suchánek" <msuchanek@suse.de>]

On Thu, May 19, 2022 at 10:22:15PM +0800, Baoquan He wrote:
> On 05/19/22 at 07:56am, Mimi Zohar wrote:
> > [Cc'ing Jarkko, linux-integrity]
> > 
> > On Thu, 2022-05-19 at 08:39 +0800, Baoquan He wrote:
> > > On 05/18/22 at 01:29pm, Heiko Carstens wrote:
> > > > On Thu, May 12, 2022 at 03:01:23PM +0800, Coiby Xu wrote:
> > > > > From: Michal Suchanek <msuchanek@suse.de>
> > > > > 
> > > > > commit e23a8020ce4e ("s390/kexec_file: Signature verification prototype")
> > > > > adds support for KEXEC_SIG verification with keys from platform keyring
> > > > > but the built-in keys and secondary keyring are not used.
> > > > > 
> > > > > Add support for the built-in keys and secondary keyring as x86 does.
> > > > > 
> > > > > Fixes: e23a8020ce4e ("s390/kexec_file: Signature verification prototype")
> > > > > Cc: stable@vger.kernel.org
> > > > > Cc: Philipp Rudo <prudo@linux.ibm.com>
> > > > > Cc: kexec@lists.infradead.org
> > > > > Cc: keyrings@vger.kernel.org
> > > > > Cc: linux-security-module@vger.kernel.org
> > > > > Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> > > > > Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
> > > > > Acked-by: Baoquan He <bhe@redhat.com>
> > > > > Signed-off-by: Coiby Xu <coxu@redhat.com>
> > > > > ---
> > > > >  arch/s390/kernel/machine_kexec_file.c | 18 +++++++++++++-----
> > > > >  1 file changed, 13 insertions(+), 5 deletions(-)
> > > > 
> > > > As far as I can tell this doesn't have any dependency to the other
> > > > patches in this series, so should I pick this up for the s390 tree, or
> > > > how will this go upstream?
> > > 
> > > Thanks, Heiko.
> > > 
> > > I want to ask Mimi if this can be taken into KEYS-ENCRYPTED tree.
> > > Otherwise I will ask Andrew to help pick this whole series.
> > > 
> > > Surely, this patch 4 can be taken into s390 seperately since it's
> > > independent, both looks good.
> > 
> > KEYS-ENCRYTPED is a type of key, unrelated to using the .platform,
> > .builtin, .machine, or .secondary keyrings.  One of the main reasons
> > for this patch set is to use the new ".machine" keyring, which, if
> > enabled, is linked to the "secondary" keyring.  However, the only
> > reference to the ".machine" keyring is in the cover letter, not any of
> > the patch descriptions.  Since this is the basis for the system's
> > integrity, this seems like a pretty big omission.
> > 
> > From patch 2/4:
> > "The code in bzImage64_verify_sig makes use of system keyrings
> > including
> > .buitin_trusted_keys, .secondary_trusted_keys and .platform keyring to
> > verify signed kernel image as PE file..."
> > 
> > From patch 3/4:
> > "This patch allows to verify arm64 kernel image signature using not
> > only
> > .builtin_trusted_keys but also .platform and .secondary_trusted_keys
> > keyring."
> > 
> > From patch 4/4:
> > "... with keys from platform keyring but the built-in keys and
> > secondary keyring are not used."
> > 
> > This patch set could probably go through KEYS/KEYRINGS_INTEGRITY, but
> > it's kind of late to be asking.  Has it been in linux-next?  Should I
> > assume this patch set has been fully tested or can we get some "tags"?
> 
> Right, it should be KEYS/KEYRINGS_INTEGRITY related, I made mistaken.
> Now it got two ACKs from Michal and me. Michal met the same issue on
> arm64 and posted another series of patches, finally Coiby integrated
> Michal's patch and his to make this patchset. That would be great if
> this can get reviewing from experts on key/keyring. Surely, Coiby need
> update the patch log to add the '.machine' keyring into patch logs as
> you pointed out.
> 
> IIRC, Coiby has tested it on x86_64/arm64, not sure if he took test on
> s390. No, this hasn't been in linux-next.

I used the s390 code on powerpc and there it did not work because the
built-in key was needed to verify the kernel.

I did not really run this on s390, only ported the fix I needed on
powerpc back to s390.

Thanks

Michal