KEYS: Add a new keyctl op to reject a key with a specified error code

Add a new keyctl op to reject a key with a specified error code.  This works
much the same as negating a key, and so keyctl_negate_key() is made a special
case of keyctl_reject_key().  The difference is that keyctl_negate_key()
selects ENOKEY as the error to be reported.

Typically the key would be rejected with EKEYEXPIRED, EKEYREVOKED or
EKEYREJECTED, but this is not mandatory.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/Documentation/keys-request-key.txt b/Documentation/keys-request-key.txt
index 09b55e46174..69686ad12c6 100644
--- a/Documentation/keys-request-key.txt
+++ b/Documentation/keys-request-key.txt
@@ -127,14 +127,15 @@ This is because process A's keyrings can't simply be attached to
 of them, and (b) it requires the same UID/GID/Groups all the way through.
 
 
-======================
-NEGATIVE INSTANTIATION
-======================
+====================================
+NEGATIVE INSTANTIATION AND REJECTION
+====================================
 
 Rather than instantiating a key, it is possible for the possessor of an
 authorisation key to negatively instantiate a key that's under construction.
 This is a short duration placeholder that causes any attempt at re-requesting
-the key whilst it exists to fail with error ENOKEY.
+the key whilst it exists to fail with error ENOKEY if negated or the specified
+error if rejected.
 
 This is provided to prevent excessive repeated spawning of /sbin/request-key
 processes for a key that will never be obtainable.