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Diffstat (limited to 'include/linux/cred.h')
-rw-r--r--include/linux/cred.h36
1 files changed, 11 insertions, 25 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 75c0fa88130..4d2c39573f3 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);
@@ -273,33 +274,18 @@ static inline void put_cred(const struct cred *_cred)
* @task: The task to query
*
* Access the objective credentials of a task. The caller must hold the RCU
- * readlock.
+ * readlock or the task must be dead and unable to change its own credentials.
*
- * 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.
+ * The result of this function should not be passed directly to get_cred();
+ * rather get_task_cred() should be used instead.
*/
-#define __task_cred(task) \
- ((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; \
-})
+#define __task_cred(task) \
+ ({ \
+ const struct task_struct *__t = (task); \
+ rcu_dereference_check(__t->real_cred, \
+ rcu_read_lock_held() || \
+ task_is_dead(__t)); \
+ })
/**
* get_current_cred - Get the current task's subjective credentials