From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933235Ab0D3Sik (ORCPT ); Fri, 30 Apr 2010 14:38:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:30982 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933118Ab0D3RVi (ORCPT ); Fri, 30 Apr 2010 13:21:38 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells Subject: [PATCH 3/7] KEYS: Use RCU dereference wrappers in keyring key type code To: torvalds@osdl.org, akpm@linux-foundation.org Cc: keyrings@linux-nfs.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, David Howells Date: Fri, 30 Apr 2010 14:32:18 +0100 Message-ID: <20100430133218.2126.28129.stgit@warthog.procyon.org.uk> In-Reply-To: <20100430133208.2126.56765.stgit@warthog.procyon.org.uk> References: <20100430133208.2126.56765.stgit@warthog.procyon.org.uk> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The keyring key type code should use RCU dereference wrappers, even when it holds the keyring's key semaphore. Reported-by: Vegard Nossum Signed-off-by: David Howells --- security/keys/keyring.c | 23 +++++++++++++---------- 1 files changed, 13 insertions(+), 10 deletions(-) diff --git a/security/keys/keyring.c b/security/keys/keyring.c index d570824..63385af 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -20,6 +20,11 @@ #include #include "internal.h" +#define rcu_dereference_locked_keyring(keyring) \ + (rcu_dereference_protected( \ + (keyring)->payload.subscriptions, \ + rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem))) + /* * when plumbing the depths of the key tree, this sets a hard limit set on how * deep we're willing to go @@ -201,8 +206,7 @@ static long keyring_read(const struct key *keyring, int loop, ret; ret = 0; - klist = keyring->payload.subscriptions; - + klist = rcu_dereference_locked_keyring(keyring); if (klist) { /* calculate how much data we could return */ qty = klist->nkeys * sizeof(key_serial_t); @@ -720,8 +724,7 @@ int __key_link(struct key *keyring, struct key *key) } /* see if there's a matching key we can displace */ - klist = keyring->payload.subscriptions; - + klist = rcu_dereference_locked_keyring(keyring); if (klist && klist->nkeys > 0) { struct key_type *type = key->type; @@ -765,8 +768,6 @@ int __key_link(struct key *keyring, struct key *key) if (ret < 0) goto error2; - klist = keyring->payload.subscriptions; - if (klist && klist->nkeys < klist->maxkeys) { /* there's sufficient slack space to add directly */ atomic_inc(&key->usage); @@ -867,7 +868,7 @@ int key_unlink(struct key *keyring, struct key *key) down_write(&keyring->sem); - klist = keyring->payload.subscriptions; + klist = rcu_dereference_locked_keyring(keyring); if (klist) { /* search the keyring for the key */ for (loop = 0; loop < klist->nkeys; loop++) @@ -958,7 +959,7 @@ int keyring_clear(struct key *keyring) /* detach the pointer block with the locks held */ down_write(&keyring->sem); - klist = keyring->payload.subscriptions; + klist = rcu_dereference_locked_keyring(keyring); if (klist) { /* adjust the quota */ key_payload_reserve(keyring, @@ -990,7 +991,9 @@ EXPORT_SYMBOL(keyring_clear); */ static void keyring_revoke(struct key *keyring) { - struct keyring_list *klist = keyring->payload.subscriptions; + struct keyring_list *klist; + + klist = rcu_dereference_locked_keyring(keyring); /* adjust the quota */ key_payload_reserve(keyring, 0); @@ -1024,7 +1027,7 @@ void keyring_gc(struct key *keyring, time_t limit) down_write(&keyring->sem); - klist = keyring->payload.subscriptions; + klist = rcu_dereference_locked_keyring(keyring); if (!klist) goto no_klist;