[patch 6/8] CAN-2005-2098 Error during attempt to join key management session can leave semaphore pinned

[Chris Wright <chrisw@osdl.org>]

[-- Attachment #1: key-session-join.patch --]
[-- Type: text/plain, Size: 1384 bytes --]

-stable review patch.  If anyone has any  objections, please let us know.
------------------

from hanging future joins in the D state [CAN-2005-2098].

The problem is that the error handling path for the KEYCTL_JOIN_SESSION_KEYRING
operation has one error path that doesn't release the session management
semaphore. Further attempts to get the semaphore will then sleep for ever in
the D state.

This can happen in four situations, all involving an attempt to allocate a new
session keyring:

 (1) ENOMEM.

 (2) The users key quota being reached.

 (3) A keyring name that is an empty string.

 (4) A keyring name that is too long.

Any user may attempt this operation, and so any user can cause the problem to
occur.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Chris Wright <chrisw@osdl.org>
---
 security/keys/process_keys.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.12.y/security/keys/process_keys.c
===================================================================
--- linux-2.6.12.y.orig/security/keys/process_keys.c
+++ linux-2.6.12.y/security/keys/process_keys.c
@@ -641,7 +641,7 @@ long join_session_keyring(const char *na
 		keyring = keyring_alloc(name, tsk->uid, tsk->gid, 0, NULL);
 		if (IS_ERR(keyring)) {
 			ret = PTR_ERR(keyring);
-			goto error;
+			goto error2;
 		}
 	}
 	else if (IS_ERR(keyring)) {

--