linux-kernel - [PATCH v4 0/3] afs: Fix dynamic root interaction with failing DNS lookups

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Message-ID: <20231221134558.1659214-1-dhowells@redhat.com>
Date: Thu, 21 Dec 2023 13:45:27 +0000
From: David Howells <dhowells@...hat.com>
To: Markus Suvanto <markus.suvanto@...il.com>,
	Marc Dionne <marc.dionne@...istor.com>
Cc: David Howells <dhowells@...hat.com>,
	linux-afs@...ts.infradead.org,
	keyrings@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v4 0/3] afs: Fix dynamic root interaction with failing DNS lookups

Hi Markus, Marc,

Here's a set of fixes to improve the interaction of arbitrary lookups in
the AFS dynamic root that hit DNS lookup failures[1]:

 (1) Always delete unused (particularly negative) dentries as soon as
     possible so that they don't prevent future lookups from retrying.

 (2) Fix the handling of new-style negative DNS lookups in ->lookup() to
     make them return ENOENT so that userspace doesn't get confused when
     stat succeeds but the following open on the looked up file then fails.

 (3) Fix key handling so that DNS lookup results are reclaimed as soon as
     they expire rather than sitting round either forever or for an
     additional 5 mins beyond a set expiry time returning EKEYEXPIRED.

The patches can be found here:

	https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=afs-fixes

Thanks,
David

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216637 [1]
Link: https://lore.kernel.org/r/20231211163412.2766147-1-dhowells@redhat.com/ # v1
Link: https://lore.kernel.org/r/20231211213233.2793525-1-dhowells@redhat.com/ # v2
Link: https://lore.kernel.org/r/20231212144611.3100234-1-dhowells@redhat.com/ # v3

Changes
=======
ver #4)
 - Reduce the negative timeout from 10s to 1s.

ver #3)
 - Rebased to v6.7-rc5 which has an additional afs patch.
 - Don't add to TIME64_MAX (ie. permanent) when checking expiry time.

ver #2)
 - Fix signed-unsigned comparison when checking return val.

David Howells (3):
  afs: Fix the dynamic root's d_delete to always delete unused dentries
  afs: Fix dynamic root lookup DNS check
  keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on
    expiry

 fs/afs/dynroot.c           | 31 +++++++++++++++++--------------
 include/linux/key-type.h   |  1 +
 net/dns_resolver/dns_key.c | 10 +++++++++-
 security/keys/gc.c         | 31 +++++++++++++++++++++----------
 security/keys/internal.h   | 11 ++++++++++-
 security/keys/key.c        | 15 +++++----------
 security/keys/proc.c       |  2 +-
 7 files changed, 64 insertions(+), 37 deletions(-)