linux-stable/net/dns_resolver
David Howells 39299bdd25 keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry
If a key has an expiration time, then when that time passes, the key is
left around for a certain amount of time before being collected (5 mins by
default) so that EKEYEXPIRED can be returned instead of ENOKEY.  This is a
problem for DNS keys because we want to redo the DNS lookup immediately at
that point.

Fix this by allowing key types to be marked such that keys of that type
don't have this extra period, but are reclaimed as soon as they expire and
turn this on for dns_resolver-type keys.  To make this easier to handle,
key->expiry is changed to be permanent if TIME64_MAX rather than 0.

Furthermore, give such new-style negative DNS results a 1s default expiry
if no other expiry time is set rather than allowing it to stick around
indefinitely.  This shouldn't be zero as ls will follow a failing stat call
immediately with a second with AT_SYMLINK_NOFOLLOW added.

Fixes: 1a4240f476 ("DNS: Separate out CIFS DNS Resolver code")
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Markus Suvanto <markus.suvanto@gmail.com>
cc: Wang Lei <wang840925@gmail.com>
cc: Jeff Layton <jlayton@redhat.com>
cc: Steve French <smfrench@gmail.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Jarkko Sakkinen <jarkko@kernel.org>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: keyrings@vger.kernel.org
cc: netdev@vger.kernel.org
2023-12-21 13:47:38 +00:00
..
Kconfig net: remove redundant 'depends on NET' 2021-01-27 17:04:12 -08:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
dns_key.c keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry 2023-12-21 13:47:38 +00:00
dns_query.c docs: networking: convert dns_resolver.txt to ReST 2020-04-28 14:39:46 -07:00
internal.h KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00