diff options
Diffstat (limited to 'include/linux/cred.h')
| -rw-r--r-- | include/linux/cred.h | 150 |
1 files changed, 74 insertions, 76 deletions
diff --git a/include/linux/cred.h b/include/linux/cred.h index 9ed9232af934..343a140a6ba2 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -12,6 +12,7 @@ #include <linux/init.h> #include <linux/key.h> #include <linux/atomic.h> +#include <linux/refcount.h> #include <linux/uidgid.h> #include <linux/sched.h> #include <linux/sched/user.h> @@ -19,11 +20,13 @@ struct cred; struct inode; +extern struct task_struct init_task; + /* * COW Supplementary groups list */ struct group_info { - atomic_t usage; + refcount_t usage; int ngroups; kgid_t gid[]; } __randomize_layout; @@ -39,7 +42,7 @@ struct group_info { */ static inline struct group_info *get_group_info(struct group_info *gi) { - atomic_inc(&gi->usage); + refcount_inc(&gi->usage); return gi; } @@ -49,7 +52,7 @@ static inline struct group_info *get_group_info(struct group_info *gi) */ #define put_group_info(group_info) \ do { \ - if (atomic_dec_and_test(&(group_info)->usage)) \ + if (refcount_dec_and_test(&(group_info)->usage)) \ groups_free(group_info); \ } while (0) @@ -108,14 +111,7 @@ static inline int groups_search(const struct group_info *group_info, kgid_t grp) * same context as task->real_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 + atomic_long_t usage; kuid_t uid; /* real UID of the task */ kgid_t gid; /* real GID of the task */ kuid_t suid; /* saved UID of the task */ @@ -154,17 +150,19 @@ 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 int copy_creds(struct task_struct *, u64); 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 int commit_creds(struct cred *); extern void abort_creds(struct cred *); -extern const struct cred *override_creds(const struct cred *); -extern void revert_creds(const struct cred *); extern struct cred *prepare_kernel_cred(struct task_struct *); -extern int change_create_files_as(struct cred *, struct inode *); +static inline const struct cred *kernel_cred(void) +{ + /* shut up sparse */ + return rcu_dereference_raw(init_task.cred); +} extern int set_security_override(struct cred *, u32); extern int set_security_override_from_ctx(struct cred *, const char *); extern int set_create_files_as(struct cred *, struct inode *); @@ -172,46 +170,6 @@ extern int cred_fscmp(const struct cred *, const struct cred *); extern void __init cred_init(void); extern int set_cred_ucounts(struct cred *); -/* - * check for validity of credentials - */ -#ifdef CONFIG_DEBUG_CREDENTIALS -extern void __noreturn __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 - static inline bool cap_ambient_invariant_ok(const struct cred *cred) { return cap_issubset(cred->cap_ambient, @@ -219,25 +177,33 @@ static inline bool cap_ambient_invariant_ok(const struct cred *cred) cred->cap_inheritable)); } -/** - * get_new_cred - Get a reference on a new set of credentials - * @cred: The new credentials to reference - * - * Get a reference on the specified set of new credentials. The caller must - * release the reference. - */ -static inline struct cred *get_new_cred(struct cred *cred) +static inline const struct cred *override_creds(const struct cred *override_cred) { - atomic_inc(&cred->usage); - return cred; + return rcu_replace_pointer(current->cred, override_cred, 1); +} + +static inline const struct cred *revert_creds(const struct cred *revert_cred) +{ + return rcu_replace_pointer(current->cred, revert_cred, 1); } +DEFINE_CLASS(override_creds, + const struct cred *, + revert_creds(_T), + override_creds(override_cred), const struct cred *override_cred) + +#define scoped_with_creds(cred) \ + scoped_class(override_creds, __UNIQUE_ID(label), cred) + +#define scoped_with_kernel_creds() scoped_with_creds(kernel_cred()) + /** - * get_cred - Get a reference on a set of credentials + * get_cred_many - Get references on a set of credentials * @cred: The credentials to reference + * @nr: Number of references to acquire * - * Get a reference on the specified set of credentials. The caller must - * release the reference. If %NULL is passed, it is returned with no action. + * Get references on the specified set of credentials. The caller must release + * all acquired reference. If %NULL is passed, it is returned with no action. * * This is used to deal with a committed set of credentials. Although the * pointer is const, this will temporarily discard the const and increment the @@ -245,14 +211,28 @@ static inline struct cred *get_new_cred(struct cred *cred) * accidental alteration of a set of credentials that should be considered * immutable. */ -static inline const struct cred *get_cred(const struct cred *cred) +static inline const struct cred *get_cred_many(const struct cred *cred, int nr) { struct cred *nonconst_cred = (struct cred *) cred; if (!cred) return cred; - validate_creds(cred); nonconst_cred->non_rcu = 0; - return get_new_cred(nonconst_cred); + atomic_long_add(nr, &nonconst_cred->usage); + return cred; +} + +/* + * get_cred - Get a reference on a set of credentials + * @cred: The credentials to reference + * + * Get a reference on the specified set of credentials. The caller must + * release the reference. If %NULL is passed, it is returned with no action. + * + * This is used to deal with a committed set of credentials. + */ +static inline const struct cred *get_cred(const struct cred *cred) +{ + return get_cred_many(cred, 1); } static inline const struct cred *get_cred_rcu(const struct cred *cred) @@ -260,9 +240,8 @@ static inline const struct cred *get_cred_rcu(const struct cred *cred) struct cred *nonconst_cred = (struct cred *) cred; if (!cred) return NULL; - if (!atomic_inc_not_zero(&nonconst_cred->usage)) + if (!atomic_long_inc_not_zero(&nonconst_cred->usage)) return NULL; - validate_creds(cred); nonconst_cred->non_rcu = 0; return cred; } @@ -270,6 +249,7 @@ static inline const struct cred *get_cred_rcu(const struct cred *cred) /** * put_cred - Release a reference to a set of credentials * @cred: The credentials to release + * @nr: Number of references to release * * Release a reference to a set of credentials, deleting them when the last ref * is released. If %NULL is passed, nothing is done. @@ -278,17 +258,35 @@ static inline const struct cred *get_cred_rcu(const struct cred *cred) * on task_struct are attached by const pointers to prevent accidental * alteration of otherwise immutable credential sets. */ -static inline void put_cred(const struct cred *_cred) +static inline void put_cred_many(const struct cred *_cred, int nr) { struct cred *cred = (struct cred *) _cred; if (cred) { - validate_creds(cred); - if (atomic_dec_and_test(&(cred)->usage)) + if (atomic_long_sub_and_test(nr, &cred->usage)) __put_cred(cred); } } +/* + * put_cred - Release a reference to a set of credentials + * @cred: The credentials to release + * + * Release a reference to a set of credentials, deleting them when the last ref + * is released. If %NULL is passed, nothing is done. + */ +static inline void put_cred(const struct cred *cred) +{ + put_cred_many(cred, 1); +} + +DEFINE_CLASS(prepare_creds, + struct cred *, + if (_T) put_cred(_T), + prepare_creds(), void) + +DEFINE_FREE(put_cred, struct cred *, if (!IS_ERR_OR_NULL(_T)) put_cred(_T)) + /** * current_cred - Access the current task's subjective credentials * |