keys: Fix overwrite of key expiration on instantiation

commit 9da27fb65a14c18efd4473e2e82b76b53ba60252 upstream.

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@amazon.com>
cc: David Howells <dhowells@redhat.com>
cc: Hazem Mohamed Abuelfotoh <abuehaze@amazon.com>
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: keyrings@vger.kernel.org
cc: netdev@vger.kernel.org
cc: stable@vger.kernel.org
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/security/keys/key.c b/security/keys/key.c
index 5b10641debd54910bbb4f2872ea6039a0471bcf5..74dfd961af96aac0fa5010f3b9785792249c407b 100644 (file)
--- 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);
                }
        }