Messages in this thread Patch in this message | | | Date | Thu, 10 Dec 2009 00:53:31 -0000 | From | Thomas Gleixner <> | Subject | [patch 9/9] security: Fix invalid rcu assumptions in comments |
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1) held spinlocks are not equivalent to rcu_read_lock
2) access to current_cred() is safe as only current can modify its own credentials.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: James Morris <jmorris@namei.org> Cc: linux-security-module@vger.kernel.org
--- security/keys/permission.c | 3 +-- security/keys/proc.c | 2 -- 2 files changed, 1 insertion(+), 4 deletions(-)
Index: linux-2.6-tip/security/keys/permission.c =================================================================== --- linux-2.6-tip.orig/security/keys/permission.c +++ linux-2.6-tip/security/keys/permission.c @@ -23,8 +23,7 @@ * Check to see whether permission is granted to use a key in the desired way, * but permit the security modules to override. * - * The caller must hold either a ref on cred or must hold the RCU readlock or a - * spinlock. + * The caller must hold either a ref on cred or must hold the RCU readlock. */ int key_task_permission(const key_ref_t key_ref, const struct cred *cred, key_perm_t perm) Index: linux-2.6-tip/security/keys/proc.c =================================================================== --- linux-2.6-tip.orig/security/keys/proc.c +++ linux-2.6-tip/security/keys/proc.c @@ -194,8 +194,6 @@ static int proc_keys_show(struct seq_fil /* check whether the current task is allowed to view the key (assuming * non-possession) - * - the caller holds a spinlock, and thus the RCU read lock, making our - * access to __current_cred() safe */ rc = key_task_permission(make_key_ref(key, 0), current_cred(), KEY_VIEW);
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