diff options
Diffstat (limited to 'include/linux/cred.h')
| -rw-r--r-- | include/linux/cred.h | 187 |
1 files changed, 143 insertions, 44 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h index a7a686074cb0..4221ec6000c1 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -37,15 +37,16 @@ struct group_info { * get_group_info - Get a reference to a group info structure * @group_info: The group info to reference * - * This must be called with the owning task locked (via task_lock()) when task - * != current. The reason being that the vast majority of callers are looking - * at current->group_info, which can not be changed except by the current task. - * Changing current->group_info requires the task lock, too. + * This gets a reference to a set of supplementary groups. + * + * If the caller is accessing a task's credentials, they must hold the RCU read + * lock when reading. */ -#define get_group_info(group_info) \ -do { \ - atomic_inc(&(group_info)->usage); \ -} while (0) +static inline struct group_info *get_group_info(struct group_info *gi) +{ + atomic_inc(&gi->usage); + return gi; +} /** * put_group_info - Release a reference to a group info structure @@ -61,7 +62,7 @@ extern struct group_info *groups_alloc(int); extern void groups_free(struct group_info *); extern int set_current_groups(struct group_info *); extern int set_groups(struct cred *, struct group_info *); -extern int groups_search(struct group_info *, gid_t); +extern int groups_search(const struct group_info *, gid_t); /* access the groups "array" with this macro */ #define GROUP_AT(gi, i) \ @@ -123,41 +124,6 @@ struct cred { spinlock_t lock; /* lock for pointer changes */ }; -#define get_current_user() (get_uid(current->cred->user)) - -#define task_uid(task) ((task)->cred->uid) -#define task_gid(task) ((task)->cred->gid) -#define task_euid(task) ((task)->cred->euid) -#define task_egid(task) ((task)->cred->egid) - -#define current_uid() (current->cred->uid) -#define current_gid() (current->cred->gid) -#define current_euid() (current->cred->euid) -#define current_egid() (current->cred->egid) -#define current_suid() (current->cred->suid) -#define current_sgid() (current->cred->sgid) -#define current_fsuid() (current->cred->fsuid) -#define current_fsgid() (current->cred->fsgid) -#define current_cap() (current->cred->cap_effective) - -#define current_uid_gid(_uid, _gid) \ -do { \ - *(_uid) = current->cred->uid; \ - *(_gid) = current->cred->gid; \ -} while(0) - -#define current_euid_egid(_uid, _gid) \ -do { \ - *(_uid) = current->cred->euid; \ - *(_gid) = current->cred->egid; \ -} while(0) - -#define current_fsuid_fsgid(_uid, _gid) \ -do { \ - *(_uid) = current->cred->fsuid; \ - *(_gid) = current->cred->fsgid; \ -} while(0) - extern void __put_cred(struct cred *); extern int copy_creds(struct task_struct *, unsigned long); @@ -187,4 +153,137 @@ static inline void put_cred(struct cred *cred) __put_cred(cred); } +/** + * current_cred - Access the current task's credentials + * + * Access the credentials of the current task. + */ +#define current_cred() \ + (current->cred) + +/** + * __task_cred - Access another task's credentials + * @task: The task to query + * + * Access the credentials of another task. The caller must hold the + * RCU readlock. + * + * 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 __task_cred(task) \ + ((const struct cred *)(rcu_dereference((task)->cred))) + +/** + * get_task_cred - Get another task's credentials + * @task: The task to query + * + * Get the 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 credentials + * + * Get the credentials of the current task, pinning them so that they can't go + * away. Accessing the current task's credentials directly is not permitted. + */ +#define get_current_cred() \ + (get_cred(current_cred())) + +/** + * get_current_user - Get the current task's user_struct + * + * Get the user record of the current task, pinning it so that it can't go + * away. + */ +#define get_current_user() \ +({ \ + struct user_struct *__u; \ + struct cred *__cred; \ + __cred = (struct cred *) current_cred(); \ + __u = get_uid(__cred->user); \ + __u; \ +}) + +/** + * get_current_groups - Get the current task's supplementary group list + * + * Get the supplementary group list of the current task, pinning it so that it + * can't go away. + */ +#define get_current_groups() \ +({ \ + struct group_info *__groups; \ + struct cred *__cred; \ + __cred = (struct cred *) current_cred(); \ + __groups = get_group_info(__cred->group_info); \ + __groups; \ +}) + +#define task_cred_xxx(task, xxx) \ +({ \ + __typeof__(task->cred->xxx) ___val; \ + rcu_read_lock(); \ + ___val = __task_cred((task))->xxx; \ + rcu_read_unlock(); \ + ___val; \ +}) + +#define task_uid(task) (task_cred_xxx((task), uid)) +#define task_euid(task) (task_cred_xxx((task), euid)) + +#define current_cred_xxx(xxx) \ +({ \ + current->cred->xxx; \ +}) + +#define current_uid() (current_cred_xxx(uid)) +#define current_gid() (current_cred_xxx(gid)) +#define current_euid() (current_cred_xxx(euid)) +#define current_egid() (current_cred_xxx(egid)) +#define current_suid() (current_cred_xxx(suid)) +#define current_sgid() (current_cred_xxx(sgid)) +#define current_fsuid() (current_cred_xxx(fsuid)) +#define current_fsgid() (current_cred_xxx(fsgid)) +#define current_cap() (current_cred_xxx(cap_effective)) +#define current_user() (current_cred_xxx(user)) +#define current_security() (current_cred_xxx(security)) + +#define current_uid_gid(_uid, _gid) \ +do { \ + const struct cred *__cred; \ + __cred = current_cred(); \ + *(_uid) = __cred->uid; \ + *(_gid) = __cred->gid; \ +} while(0) + +#define current_euid_egid(_euid, _egid) \ +do { \ + const struct cred *__cred; \ + __cred = current_cred(); \ + *(_euid) = __cred->euid; \ + *(_egid) = __cred->egid; \ +} while(0) + +#define current_fsuid_fsgid(_fsuid, _fsgid) \ +do { \ + const struct cred *__cred; \ + __cred = current_cred(); \ + *(_fsuid) = __cred->fsuid; \ + *(_fsgid) = __cred->fsgid; \ +} while(0) + #endif /* _LINUX_CRED_H */ |