[SRU][j:azure][PATCH 1/1] keys: Fix overwrite of key expiration on instantiation

[John Cabaj]

From: Silvio Gissi <sifonsec at amazon.com>

BugLink: https://bugs.launchpad.net/bugs/2070076

The expiry time of a key is unconditionally overwritten during
instantiation, defaulting to turn it permanent. This causes a problem
for DNS resolution as the expiration set by user-space is overwritten to
TIME64_MAX, disabling further DNS updates. Fix this by restoring the
condition that key_set_expiry is only called when the pre-parser sets a
specific expiry.

Fixes: 39299bdd2546 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
Signed-off-by: Silvio Gissi <sifonsec at amazon.com>
cc: David Howells <dhowells at redhat.com>
cc: Hazem Mohamed Abuelfotoh <abuehaze at amazon.com>
cc: linux-afs at lists.infradead.org
cc: linux-cifs at vger.kernel.org
cc: keyrings at vger.kernel.org
cc: netdev at vger.kernel.org
cc: stable at vger.kernel.org
Reviewed-by: Jarkko Sakkinen <jarkko at kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko at kernel.org>
(cherry picked from commit 9da27fb65a14c18efd4473e2e82b76b53ba60252)
Signed-off-by: John Cabaj <john.cabaj at canonical.com>
---
 security/keys/key.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/keys/key.c b/security/keys/key.c
index e65240641ca5..f2a84d86eab4 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -464,7 +464,8 @@ static int __key_instantiate_and_link(struct key *key,
 			if (authkey)
 				key_invalidate(authkey);
 
-			key_set_expiry(key, prep->expiry);
+			if (prep->expiry != TIME64_MAX)
+				key_set_expiry(key, prep->expiry);
 		}
 	}
 
-- 
2.34.1