diff options
Diffstat (limited to 'include/linux/cred.h')
| -rw-r--r-- | include/linux/cred.h | 95 |
1 files changed, 66 insertions, 29 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h index 4fa999696310..4aaeab376446 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -15,6 +15,7 @@ #include <linux/capability.h> #include <linux/init.h> #include <linux/key.h> +#include <linux/selinux.h> #include <asm/atomic.h> struct user_struct; @@ -83,7 +84,7 @@ struct thread_group_cred { atomic_t usage; pid_t tgid; /* thread group process ID */ spinlock_t lock; - struct key *session_keyring; /* keyring inherited over fork */ + struct key __rcu *session_keyring; /* keyring inherited over fork */ struct key *process_keyring; /* keyring private to this process */ struct rcu_head rcu; /* RCU deletion hook */ }; @@ -114,6 +115,13 @@ struct thread_group_cred { */ struct cred { atomic_t usage; +#ifdef CONFIG_DEBUG_CREDENTIALS + atomic_t subscribers; /* number of processes subscribed */ + void *put_addr; + unsigned magic; +#define CRED_MAGIC 0x43736564 +#define CRED_MAGIC_DEAD 0x44656144 +#endif uid_t uid; /* real UID of the task */ gid_t gid; /* real GID of the task */ uid_t suid; /* saved UID of the task */ @@ -143,10 +151,12 @@ 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); -extern struct cred *prepare_usermodehelper_creds(void); extern int commit_creds(struct cred *); extern void abort_creds(struct cred *); extern const struct cred *override_creds(const struct cred *); @@ -158,6 +168,46 @@ extern int set_security_override_from_ctx(struct cred *, const char *); extern int set_create_files_as(struct cred *, struct inode *); extern void __init cred_init(void); +/* + * check for validity of credentials + */ +#ifdef CONFIG_DEBUG_CREDENTIALS +extern void __invalid_creds(const struct cred *, const char *, unsigned); +extern void __validate_process_creds(struct task_struct *, + const char *, unsigned); + +extern bool creds_are_invalid(const struct cred *cred); + +static inline void __validate_creds(const struct cred *cred, + const char *file, unsigned line) +{ + if (unlikely(creds_are_invalid(cred))) + __invalid_creds(cred, file, line); +} + +#define validate_creds(cred) \ +do { \ + __validate_creds((cred), __FILE__, __LINE__); \ +} while(0) + +#define validate_process_creds() \ +do { \ + __validate_process_creds(current, __FILE__, __LINE__); \ +} while(0) + +extern void validate_creds_for_do_exit(struct task_struct *); +#else +static inline void validate_creds(const struct cred *cred) +{ +} +static inline void validate_creds_for_do_exit(struct task_struct *tsk) +{ +} +static inline void validate_process_creds(void) +{ +} +#endif + /** * get_new_cred - Get a reference on a new set of credentials * @cred: The new credentials to reference @@ -186,7 +236,9 @@ static inline struct cred *get_new_cred(struct cred *cred) */ static inline const struct cred *get_cred(const struct cred *cred) { - return get_new_cred((struct cred *) cred); + struct cred *nonconst_cred = (struct cred *) cred; + validate_creds(cred); + return get_new_cred(nonconst_cred); } /** @@ -204,7 +256,7 @@ static inline void put_cred(const struct cred *_cred) { struct cred *cred = (struct cred *) _cred; - BUG_ON(atomic_read(&(cred)->usage) <= 0); + validate_creds(cred); if (atomic_dec_and_test(&(cred)->usage)) __put_cred(cred); } @@ -222,33 +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. - * - * 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)->real_cred))) - -/** - * get_task_cred - Get another task's objective credentials - * @task: The task to query + * readlock or the task must be dead and unable to change its own credentials. * - * 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. + * The result of this function should not be passed directly to get_cred(); + * rather get_task_cred() should be used instead. */ -#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 |