Re: [GIT PULL] Keys: Set 4 - Key ACLs for 5.3

From: Eric Biggers <ebiggers@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Howells <dhowells@redhat.com>,
	James Morris James Morris <jmorris@namei.org>,
	keyrings@vger.kernel.org, Netdev <netdev@vger.kernel.org>,
	linux-nfs@vger.kernel.org, CIFS <linux-cifs@vger.kernel.org>,
	linux-afs@lists.infradead.org,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-integrity@vger.kernel.org,
	LSM List <linux-security-module@vger.kernel.org>,
	Linux List Kernel Mailing <linux-kernel@vger.kernel.org>
Subject: Re: [GIT PULL] Keys: Set 4 - Key ACLs for 5.3
Date: Wed, 10 Jul 2019 12:46:22 -0700	[thread overview]
Message-ID: <20190710194620.GA83443@gmail.com> (raw)
In-Reply-To: <CAHk-=wjxoeMJfeBahnWH=9zShKp2bsVy527vo3_y8HfOdhwAAw@mail.gmail.com>

On Wed, Jul 10, 2019 at 11:35:07AM -0700, Linus Torvalds wrote:
> On Fri, Jul 5, 2019 at 2:30 PM David Howells <dhowells@redhat.com> wrote:
> >
> > Here's my fourth block of keyrings changes for the next merge window.  They
> > change the permissions model used by keys and keyrings to be based on an
> > internal ACL by the following means:
> 
> It turns out that this is broken, and I'll probably have to revert the
> merge entirely.
> 
> With this merge in place, I can't boot any of the machines that have
> an encrypted disk setup. The boot just stops at
> 
>   systemd[1]: Started Forward Password Requests to Plymouth Directory Watch.
>   systemd[1]: Reached target Paths.
> 
> and never gets any further. I never get the prompt for a passphrase
> for the disk encryption.
> 
> Apparently not a lot of developers are using encrypted volumes for
> their development machines.
> 
> I'm not sure if the only requirement is an encrypted volume, or if
> this is also particular to a F30 install in case you need to be able
> to reproduce. But considering that you have a redhat email address,
> I'm sure you can find a F30 install somewhere with an encrypted disk.
> 
> David, if you can fix this quickly, I'll hold off on the revert of it
> all, but I can wait only so long. I've stopped merging stuff since I
> noticed my machines don't work (this merge window has not been
> pleasant so far - in addition to this issue I had another entirely
> unrelated boot failure which made bisecting this one even more fun).
> 
> So if I don't see a quick fix, I'll just revert in order to then
> continue to do pull requests later today. Because I do not want to do
> further pulls with something that I can't boot as a base.
> 
>                  Linus

This also broke 'keyctl new_session' and hence all the fscrypt tests
(https://lkml.kernel.org/lkml/20190710011559.GA7973@sol.localdomain/), and it
also broke loading in-kernel X.509 certificates
(https://lore.kernel.org/lkml/27671.1562384658@turing-police/T/#u).

I'm *guessing* these are all some underlying issue where keyrings aren't being
given all the needed permissions anymore.

But just FYI, David had said he's on vacation with no laptop or email access for
2 weeks starting from Sunday (3 days ago).  So I don't think you can expect a
quick fix from him.

I was planning to look into this to fix the fscrypt tests, but it might be a few
days before I get to it.  And while I'm *guessing* it will be a simple fix, it
might not be.  So I can't speak for David, but personally I'm fine with the
commits being reverted for now.

I'm also unhappy that the new keyctl KEYCTL_GRANT_PERMISSION doesn't have any
documentation or tests.  (Which seems to be a common problem with David's
work...  None of the new mount syscalls in v5.2 have any tests, for example, and
the man pages are still work-in-progress and last sent out for review a year
ago, despite API changes that occurred before the syscalls were merged.)

- Eric