Patch "KEYS: Don't permit request_key() to construct a new keyring" has been added to the 3.18-stable tree

This is a note to let you know that I've just added the patch titled

KEYS: Don't permit request_key() to construct a new keyring

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
keys-don-t-permit-request_key-to-construct-a-new-keyring.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: David Howells <[email protected]>
Date: Mon, 19 Oct 2015 11:20:28 +0100
Subject: KEYS: Don't permit request_key() to construct a new keyring

From: David Howells <[email protected]>

commit 911b79cde95c7da0ec02f48105358a36636b7a71 upstream.

If request_key() is used to find a keyring, only do the search part - don't do the construction part if the keyring was not found by the search. We don't really want keyrings in the negative instantiated state since the rejected/negative instantiation error value in the payload is unioned with keyring metadata.

Now the kernel gives an error:

request_key("keyring", "#selinux,bdekeyring", "keyring", KEY_SPEC_USER_SESSION_KEYRING) = -1 EPERM (Operation not permitted)

---
 security/keys/request_key.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -467,6 +467,9 @@ static struct key *construct_key_and_lin
 	if (ret)
 		goto error;
 
+	if (ctx->index_key.type == &key_type_keyring)
+		return ERR_PTR(-EPERM);
+
 	user = key_user_lookup(current_fsuid());
 	if (!user) {
 		ret = -ENOMEM;

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/keys-don-t-permit-request_key-to-construct-a-new-keyring.patch queue-3.18/don-t-leak-a-key-reference-if-request_key-tries-to-use-a-revoked-keyring.patch