diff options
| -rw-r--r-- | fs/proc/array.c | 2 | ||||
| -rw-r--r-- | include/linux/cred.h | 21 | ||||
| -rw-r--r-- | kernel/cred.c | 25 |
3 files changed, 27 insertions, 21 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 9b58d38..fff6572 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -176,7 +176,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns, if (tracer) tpid = task_pid_nr_ns(tracer, ns); } - cred = get_cred((struct cred *) __task_cred(p)); + cred = get_task_cred(p); seq_printf(m, "State:\t%s\n" "Tgid:\t%d\n" diff --git a/include/linux/cred.h b/include/linux/cred.h index 75c0fa8..ce40cbc 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -153,6 +153,7 @@ struct cred { extern void __put_cred(struct cred *); extern void exit_creds(struct task_struct *); extern int copy_creds(struct task_struct *, unsigned long); +extern const struct cred *get_task_cred(struct task_struct *); extern struct cred *cred_alloc_blank(void); extern struct cred *prepare_creds(void); extern struct cred *prepare_exec_creds(void); @@ -282,26 +283,6 @@ static inline void put_cred(const struct cred *_cred) ((const struct cred *)(rcu_dereference_check((task)->real_cred, rcu_read_lock_held() || lockdep_tasklist_lock_is_held()))) /** - * get_task_cred - Get another task's objective credentials - * @task: The task to query - * - * Get the objective credentials of a task, pinning them so that they can't go - * away. Accessing a task's credentials directly is not permitted. - * - * The caller must make sure task doesn't go away, either by holding a ref on - * task or by holding tasklist_lock to prevent it from being unlinked. - */ -#define get_task_cred(task) \ -({ \ - struct cred *__cred; \ - rcu_read_lock(); \ - __cred = (struct cred *) __task_cred((task)); \ - get_cred(__cred); \ - rcu_read_unlock(); \ - __cred; \ -}) - -/** * get_current_cred - Get the current task's subjective credentials * * Get the subjective credentials of the current task, pinning them so that diff --git a/kernel/cred.c b/kernel/cred.c index a2d5504..60bc8b1 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -209,6 +209,31 @@ void exit_creds(struct task_struct *tsk) } } +/** + * get_task_cred - Get another task's objective credentials + * @task: The task to query + * + * Get the objective credentials of a task, pinning them so that they can't go + * away. Accessing a task's credentials directly is not permitted. + * + * The caller must also make sure task doesn't get deleted, either by holding a + * ref on task or by holding tasklist_lock to prevent it from being unlinked. + */ +const struct cred *get_task_cred(struct task_struct *task) +{ + const struct cred *cred; + + rcu_read_lock(); + + do { + cred = __task_cred((task)); + BUG_ON(!cred); + } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage)); + + rcu_read_unlock(); + return cred; +} + /* * Allocate blank credentials, such that the credentials can be filled in at a * later date without risk of ENOMEM. |
