[linux-block.git] / include / linux / cred.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Credentials management - see Documentation/security/credentials.rst
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#ifndef _LINUX_CRED_H
#define _LINUX_CRED_H

#include <linux/capability.h>
#include <linux/init.h>
#include <linux/key.h>
#include <linux/atomic.h>
#include <linux/uidgid.h>
#include <linux/sched.h>
#include <linux/sched/user.h>

struct cred;
struct inode;

/*
 * COW Supplementary groups list
 */
struct group_info {
	atomic_t	usage;
	int		ngroups;
	kgid_t		gid[];
} __randomize_layout;

/**
 * get_group_info - Get a reference to a group info structure
 * @group_info: The group info to reference
 *
 * 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.
 */
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
 * @group_info: The group info to release
 */
#define put_group_info(group_info)			\
do {							\
	if (atomic_dec_and_test(&(group_info)->usage))	\
		groups_free(group_info);		\
} while (0)

#ifdef CONFIG_MULTIUSER
extern struct group_info *groups_alloc(int);
extern void groups_free(struct group_info *);

extern int in_group_p(kgid_t);
extern int in_egroup_p(kgid_t);
extern int groups_search(const struct group_info *, kgid_t);

extern int set_current_groups(struct group_info *);
extern void set_groups(struct cred *, struct group_info *);
extern bool may_setgroups(void);
extern void groups_sort(struct group_info *);
#else
static inline void groups_free(struct group_info *group_info)
{
}

static inline int in_group_p(kgid_t grp)
{
        return 1;
}
static inline int in_egroup_p(kgid_t grp)
{
        return 1;
}
static inline int groups_search(const struct group_info *group_info, kgid_t grp)
{
	return 1;
}
#endif

/*
 * The security context of a task
 *
 * The parts of the context break down into two categories:
 *
 *  (1) The objective context of a task.  These parts are used when some other
 *	task is attempting to affect this one.
 *
 *  (2) The subjective context.  These details are used when the task is acting
 *	upon another object, be that a file, a task, a key or whatever.
 *
 * Note that some members of this structure belong to both categories - the
 * LSM security pointer for instance.
 *
 * A task has two security pointers.  task->real_cred points to the objective
 * context that defines that task's actual details.  The objective part of this
 * context is used whenever that task is acted upon.
 *
 * task->cred points to the subjective context that defines the details of how
 * that task is going to act upon another object.  This may be overridden
 * temporarily to point to another security context, but normally points to the
 * 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
	kuid_t		uid;		/* real UID of the task */
	kgid_t		gid;		/* real GID of the task */
	kuid_t		suid;		/* saved UID of the task */
	kgid_t		sgid;		/* saved GID of the task */
	kuid_t		euid;		/* effective UID of the task */
	kgid_t		egid;		/* effective GID of the task */
	kuid_t		fsuid;		/* UID for VFS ops */
	kgid_t		fsgid;		/* GID for VFS ops */
	unsigned	securebits;	/* SUID-less security management */
	kernel_cap_t	cap_inheritable; /* caps our children can inherit */
	kernel_cap_t	cap_permitted;	/* caps we're permitted */
	kernel_cap_t	cap_effective;	/* caps we can actually use */
	kernel_cap_t	cap_bset;	/* capability bounding set */
	kernel_cap_t	cap_ambient;	/* Ambient capability set */
#ifdef CONFIG_KEYS
	unsigned char	jit_keyring;	/* default keyring to attach requested
					 * keys to */
	struct key	*session_keyring; /* keyring inherited over fork */
	struct key	*process_keyring; /* keyring private to this process */
	struct key	*thread_keyring; /* keyring private to this thread */
	struct key	*request_key_auth; /* assumed request_key authority */
#endif
#ifdef CONFIG_SECURITY
	void		*security;	/* LSM security */
#endif
	struct user_struct *user;	/* real user ID subscription */
	struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */
	struct group_info *group_info;	/* supplementary groups for euid/fsgid */
	/* RCU deletion */
	union {
		int non_rcu;			/* Can we skip RCU deletion? */
		struct rcu_head	rcu;		/* RCU deletion hook */
	};
} __randomize_layout;

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 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 *);
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 *);
extern int cred_fscmp(const struct cred *, const struct cred *);
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

static inline bool cap_ambient_invariant_ok(const struct cred *cred)
{
	return cap_issubset(cred->cap_ambient,
			    cap_intersect(cred->cap_permitted,
					  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)
{
	atomic_inc(&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.  Although the
 * pointer is const, this will temporarily discard the const and increment the
 * usage count.  The purpose of this is to attempt to catch at compile time the
 * accidental alteration of a set of credentials that should be considered
 * immutable.
 */
static inline const struct cred *get_cred(const struct cred *cred)
{
	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);
}

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))
		return NULL;
	validate_creds(cred);
	nonconst_cred->non_rcu = 0;
	return 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.
 *
 * This takes a const pointer to a set of credentials because the credentials
 * 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)
{
	struct cred *cred = (struct cred *) _cred;

	if (cred) {
		validate_creds(cred);
		if (atomic_dec_and_test(&(cred)->usage))
			__put_cred(cred);
	}
}

/**
 * current_cred - Access the current task's subjective credentials
 *
 * Access the subjective credentials of the current task.  RCU-safe,
 * since nobody else can modify it.
 */
#define current_cred() \
	rcu_dereference_protected(current->cred, 1)

/**
 * current_real_cred - Access the current task's objective credentials
 *
 * Access the objective credentials of the current task.  RCU-safe,
 * since nobody else can modify it.
 */
#define current_real_cred() \
	rcu_dereference_protected(current->real_cred, 1)

/**
 * __task_cred - Access a task's objective credentials
 * @task: The task to query
 *
 * Access the objective credentials of a task.  The caller must hold the RCU
 * readlock.
 *
 * 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)	\
	rcu_dereference((task)->real_cred)

/**
 * get_current_cred - Get the current task's subjective credentials
 *
 * Get the subjective 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;			\
	const struct cred *__cred;			\
	__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;			\
	const struct cred *__cred;			\
	__cred = current_cred();			\
	__groups = get_group_info(__cred->group_info);	\
	__groups;					\
})

#define task_cred_xxx(task, xxx)			\
({							\
	__typeof__(((struct cred *)NULL)->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))

extern struct user_namespace init_user_ns;
#ifdef CONFIG_USER_NS
#define current_user_ns()	(current_cred_xxx(user_ns))
#else
static inline struct user_namespace *current_user_ns(void)
{
	return &init_user_ns;
}
#endif


#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 */
Commit	Line	Data
b4d0d230	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
af777cd1	2	/* Credentials management - see Documentation/security/credentials.rst
9e2b2dc4 DH	3	*
	4	* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
9e2b2dc4 DH	6	*/
	7
	8	#ifndef _LINUX_CRED_H
	9	#define _LINUX_CRED_H
	10
b6dff3ec	11	#include <linux/capability.h>
b2e1feaf	12	#include <linux/init.h>
b6dff3ec	13	#include <linux/key.h>
60063497	14	#include <linux/atomic.h>
ae2975bc	15	#include <linux/uidgid.h>
5b825c3a	16	#include <linux/sched.h>
8703e8a4	17	#include <linux/sched/user.h>
b6dff3ec	18
b6dff3ec	19	struct cred;
3a3b7ce9	20	struct inode;
b6dff3ec DH	21
	22	/*
	23	* COW Supplementary groups list
	24	*/
b6dff3ec DH	25	struct group_info {
	26	atomic_t usage;
	27	int ngroups;
c1f26493	28	kgid_t gid[];
3859a271	29	} __randomize_layout;
b6dff3ec DH	30
	31	/**
	32	* get_group_info - Get a reference to a group info structure
	33	* @group_info: The group info to reference
	34	*
86a264ab DH	35	* This gets a reference to a set of supplementary groups.
	36	*
	37	* If the caller is accessing a task's credentials, they must hold the RCU read
	38	* lock when reading.
b6dff3ec	39	*/
86a264ab DH	40	static inline struct group_info get_group_info(struct group_info gi)
	41	{
	42	atomic_inc(&gi->usage);
	43	return gi;
	44	}
b6dff3ec DH	45
	46	/**
	47	* put_group_info - Release a reference to a group info structure
	48	* @group_info: The group info to release
	49	*/
	50	#define put_group_info(group_info) \
	51	do { \
	52	if (atomic_dec_and_test(&(group_info)->usage)) \
	53	groups_free(group_info); \
	54	} while (0)
	55
2813893f IM	56	#ifdef CONFIG_MULTIUSER
2813893f IM	57	extern struct group_info *groups_alloc(int);
b6dff3ec	58	extern void groups_free(struct group_info *);
2813893f IM	59
	60	extern int in_group_p(kgid_t);
	61	extern int in_egroup_p(kgid_t);
4b09791b OM	62	extern int groups_search(const struct group_info *, kgid_t);
	63
	64	extern int set_current_groups(struct group_info *);
	65	extern void set_groups(struct cred , struct group_info );
	66	extern bool may_setgroups(void);
	67	extern void groups_sort(struct group_info *);
2813893f IM	68	#else
	69	static inline void groups_free(struct group_info *group_info)
	70	{
	71	}
	72
	73	static inline int in_group_p(kgid_t grp)
	74	{
	75	return 1;
	76	}
	77	static inline int in_egroup_p(kgid_t grp)
	78	{
	79	return 1;
	80	}
4b09791b OM	81	static inline int groups_search(const struct group_info *group_info, kgid_t grp)
	82	{
	83	return 1;
	84	}
2813893f	85	#endif
b6dff3ec	86
b6dff3ec DH	87	/*
	88	* The security context of a task
	89	*
	90	* The parts of the context break down into two categories:
	91	*
	92	* (1) The objective context of a task. These parts are used when some other
	93	* task is attempting to affect this one.
	94	*
	95	* (2) The subjective context. These details are used when the task is acting
	96	* upon another object, be that a file, a task, a key or whatever.
	97	*
	98	* Note that some members of this structure belong to both categories - the
	99	* LSM security pointer for instance.
	100	*
	101	* A task has two security pointers. task->real_cred points to the objective
	102	* context that defines that task's actual details. The objective part of this
	103	* context is used whenever that task is acted upon.
	104	*
	105	* task->cred points to the subjective context that defines the details of how
	106	* that task is going to act upon another object. This may be overridden
	107	* temporarily to point to another security context, but normally points to the
	108	* same context as task->real_cred.
	109	*/
	110	struct cred {
	111	atomic_t usage;
e0e81739 DH	112	#ifdef CONFIG_DEBUG_CREDENTIALS
	113	atomic_t subscribers; /* number of processes subscribed */
	114	void *put_addr;
	115	unsigned magic;
	116	#define CRED_MAGIC 0x43736564
	117	#define CRED_MAGIC_DEAD 0x44656144
	118	#endif
078de5f7 EB	119	kuid_t uid; /* real UID of the task */
	120	kgid_t gid; /* real GID of the task */
	121	kuid_t suid; /* saved UID of the task */
	122	kgid_t sgid; /* saved GID of the task */
	123	kuid_t euid; /* effective UID of the task */
	124	kgid_t egid; /* effective GID of the task */
	125	kuid_t fsuid; /* UID for VFS ops */
	126	kgid_t fsgid; /* GID for VFS ops */
b6dff3ec DH	127	unsigned securebits; /* SUID-less security management */
	128	kernel_cap_t cap_inheritable; /* caps our children can inherit */
	129	kernel_cap_t cap_permitted; /* caps we're permitted */
	130	kernel_cap_t cap_effective; /* caps we can actually use */
	131	kernel_cap_t cap_bset; /* capability bounding set */
58319057	132	kernel_cap_t cap_ambient; /* Ambient capability set */
b6dff3ec DH	133	#ifdef CONFIG_KEYS
	134	unsigned char jit_keyring; /* default keyring to attach requested
	135	* keys to */
5c7e372c	136	struct key session_keyring; / keyring inherited over fork */
3a50597d	137	struct key process_keyring; / keyring private to this process */
b6dff3ec DH	138	struct key thread_keyring; / keyring private to this thread */
	139	struct key request_key_auth; / assumed request_key authority */
	140	#endif
	141	#ifdef CONFIG_SECURITY
4ebd7651	142	void security; / LSM security */
b6dff3ec DH	143	#endif
b6dff3ec DH	144	struct user_struct user; / real user ID subscription */
0093ccb6	145	struct user_namespace user_ns; / user_ns the caps and keyrings are relative to. */
b6dff3ec	146	struct group_info group_info; / supplementary groups for euid/fsgid */
d7852fbd LT	147	/* RCU deletion */
	148	union {
	149	int non_rcu; /* Can we skip RCU deletion? */
	150	struct rcu_head rcu; /* RCU deletion hook */
	151	};
3859a271	152	} __randomize_layout;
b6dff3ec	153
f1752eec	154	extern void __put_cred(struct cred *);
e0e81739	155	extern void exit_creds(struct task_struct *);
f1752eec	156	extern int copy_creds(struct task_struct *, unsigned long);
de09a977	157	extern const struct cred get_task_cred(struct task_struct );
ee18d64c	158	extern struct cred *cred_alloc_blank(void);
d84f4f99	159	extern struct cred *prepare_creds(void);
a6f76f23	160	extern struct cred *prepare_exec_creds(void);
d84f4f99 DH	161	extern int commit_creds(struct cred *);
d84f4f99 DH	162	extern void abort_creds(struct cred *);
3b11a1de DH	163	extern const struct cred override_creds(const struct cred );
3b11a1de DH	164	extern void revert_creds(const struct cred *);
3a3b7ce9 DH	165	extern struct cred prepare_kernel_cred(struct task_struct );
	166	extern int change_create_files_as(struct cred , struct inode );
	167	extern int set_security_override(struct cred *, u32);
	168	extern int set_security_override_from_ctx(struct cred , const char );
	169	extern int set_create_files_as(struct cred , struct inode );
d89b22d4	170	extern int cred_fscmp(const struct cred , const struct cred );
d84f4f99 DH	171	extern void __init cred_init(void);
d84f4f99 DH	172
e0e81739 DH	173	/*
	174	* check for validity of credentials
	175	*/
	176	#ifdef CONFIG_DEBUG_CREDENTIALS
	177	extern void __invalid_creds(const struct cred , const char , unsigned);
	178	extern void __validate_process_creds(struct task_struct *,
	179	const char *, unsigned);
	180
74908a00	181	extern bool creds_are_invalid(const struct cred *cred);
e0e81739 DH	182
	183	static inline void __validate_creds(const struct cred *cred,
	184	const char *file, unsigned line)
	185	{
	186	if (unlikely(creds_are_invalid(cred)))
	187	__invalid_creds(cred, file, line);
	188	}
	189
	190	#define validate_creds(cred) \
	191	do { \
	192	__validate_creds((cred), __FILE__, __LINE__); \
	193	} while(0)
	194
	195	#define validate_process_creds() \
	196	do { \
	197	__validate_process_creds(current, __FILE__, __LINE__); \
	198	} while(0)
	199
	200	extern void validate_creds_for_do_exit(struct task_struct *);
	201	#else
	202	static inline void validate_creds(const struct cred *cred)
	203	{
	204	}
	205	static inline void validate_creds_for_do_exit(struct task_struct *tsk)
	206	{
	207	}
	208	static inline void validate_process_creds(void)
	209	{
	210	}
	211	#endif
	212
58319057 AL	213	static inline bool cap_ambient_invariant_ok(const struct cred *cred)
	214	{
	215	return cap_issubset(cred->cap_ambient,
	216	cap_intersect(cred->cap_permitted,
	217	cred->cap_inheritable));
	218	}
	219
d84f4f99 DH	220	/**
	221	* get_new_cred - Get a reference on a new set of credentials
	222	* @cred: The new credentials to reference
	223	*
	224	* Get a reference on the specified set of new credentials. The caller must
	225	* release the reference.
	226	*/
	227	static inline struct cred get_new_cred(struct cred cred)
	228	{
	229	atomic_inc(&cred->usage);
	230	return cred;
	231	}
f1752eec DH	232
	233	/**
	234	* get_cred - Get a reference on a set of credentials
	235	* @cred: The credentials to reference
	236	*
	237	* Get a reference on the specified set of credentials. The caller must
f06bc033	238	* release the reference. If %NULL is passed, it is returned with no action.
98870ab0 DH	239	*
	240	* This is used to deal with a committed set of credentials. Although the
	241	* pointer is const, this will temporarily discard the const and increment the
	242	* usage count. The purpose of this is to attempt to catch at compile time the
	243	* accidental alteration of a set of credentials that should be considered
	244	* immutable.
f1752eec	245	*/
d84f4f99	246	static inline const struct cred get_cred(const struct cred cred)
f1752eec	247	{
1c388ad0	248	struct cred nonconst_cred = (struct cred ) cred;
f06bc033 N	249	if (!cred)
f06bc033 N	250	return cred;
e0e81739	251	validate_creds(cred);
d7852fbd	252	nonconst_cred->non_rcu = 0;
1c388ad0	253	return get_new_cred(nonconst_cred);
f1752eec DH	254	}
f1752eec DH	255
97d0fb23 N	256	static inline const struct cred get_cred_rcu(const struct cred cred)
	257	{
	258	struct cred nonconst_cred = (struct cred ) cred;
	259	if (!cred)
	260	return NULL;
	261	if (!atomic_inc_not_zero(&nonconst_cred->usage))
	262	return NULL;
	263	validate_creds(cred);
d7852fbd	264	nonconst_cred->non_rcu = 0;
97d0fb23 N	265	return cred;
	266	}
	267
f1752eec DH	268	/**
	269	* put_cred - Release a reference to a set of credentials
	270	* @cred: The credentials to release
	271	*
	272	* Release a reference to a set of credentials, deleting them when the last ref
f06bc033	273	* is released. If %NULL is passed, nothing is done.
98870ab0 DH	274	*
	275	* This takes a const pointer to a set of credentials because the credentials
	276	* on task_struct are attached by const pointers to prevent accidental
	277	* alteration of otherwise immutable credential sets.
f1752eec	278	*/
c69e8d9c	279	static inline void put_cred(const struct cred *_cred)
f1752eec	280	{
c69e8d9c	281	struct cred cred = (struct cred ) _cred;
d84f4f99	282
f06bc033 N	283	if (cred) {
	284	validate_creds(cred);
	285	if (atomic_dec_and_test(&(cred)->usage))
	286	__put_cred(cred);
	287	}
f1752eec DH	288	}
f1752eec DH	289
86a264ab	290	/**
3b11a1de	291	* current_cred - Access the current task's subjective credentials
86a264ab	292	*
32955148 AV	293	* Access the subjective credentials of the current task. RCU-safe,
32955148 AV	294	* since nobody else can modify it.
86a264ab DH	295	*/
86a264ab DH	296	#define current_cred() \
27e4e436	297	rcu_dereference_protected(current->cred, 1)
86a264ab	298
ae4b884f JL	299	/**
	300	* current_real_cred - Access the current task's objective credentials
	301	*
	302	* Access the objective credentials of the current task. RCU-safe,
	303	* since nobody else can modify it.
	304	*/
	305	#define current_real_cred() \
	306	rcu_dereference_protected(current->real_cred, 1)
	307
86a264ab	308	/**
3b11a1de	309	* __task_cred - Access a task's objective credentials
86a264ab DH	310	* @task: The task to query
86a264ab DH	311	*
3b11a1de	312	* Access the objective credentials of a task. The caller must hold the RCU
43e13cc1	313	* readlock.
86a264ab	314	*
8f92054e DH	315	* The result of this function should not be passed directly to get_cred();
8f92054e DH	316	* rather get_task_cred() should be used instead.
86a264ab	317	*/
43e13cc1 ON	318	#define __task_cred(task) \
43e13cc1 ON	319	rcu_dereference((task)->real_cred)
86a264ab	320
86a264ab	321	/**
3b11a1de	322	* get_current_cred - Get the current task's subjective credentials
86a264ab	323	*
3b11a1de DH	324	* Get the subjective credentials of the current task, pinning them so that
	325	* they can't go away. Accessing the current task's credentials directly is
	326	* not permitted.
86a264ab DH	327	*/
	328	#define get_current_cred() \
	329	(get_cred(current_cred()))
	330
	331	/**
	332	* get_current_user - Get the current task's user_struct
	333	*
	334	* Get the user record of the current task, pinning it so that it can't go
	335	* away.
	336	*/
	337	#define get_current_user() \
	338	({ \
	339	struct user_struct *__u; \
638a8439	340	const struct cred *__cred; \
32955148	341	__cred = current_cred(); \
86a264ab DH	342	__u = get_uid(__cred->user); \
	343	__u; \
	344	})
	345
	346	/**
	347	* get_current_groups - Get the current task's supplementary group list
	348	*
	349	* Get the supplementary group list of the current task, pinning it so that it
	350	* can't go away.
	351	*/
	352	#define get_current_groups() \
	353	({ \
	354	struct group_info *__groups; \
638a8439	355	const struct cred *__cred; \
32955148	356	__cred = current_cred(); \
86a264ab DH	357	__groups = get_group_info(__cred->group_info); \
	358	__groups; \
	359	})
	360
d84f4f99 DH	361	#define task_cred_xxx(task, xxx) \
	362	({ \
	363	__typeof__(((struct cred *)NULL)->xxx) ___val; \
	364	rcu_read_lock(); \
	365	___val = __task_cred((task))->xxx; \
	366	rcu_read_unlock(); \
	367	___val; \
86a264ab DH	368	})
	369
	370	#define task_uid(task) (task_cred_xxx((task), uid))
	371	#define task_euid(task) (task_cred_xxx((task), euid))
	372
	373	#define current_cred_xxx(xxx) \
	374	({ \
32955148	375	current_cred()->xxx; \
86a264ab DH	376	})
	377
	378	#define current_uid() (current_cred_xxx(uid))
	379	#define current_gid() (current_cred_xxx(gid))
	380	#define current_euid() (current_cred_xxx(euid))
	381	#define current_egid() (current_cred_xxx(egid))
	382	#define current_suid() (current_cred_xxx(suid))
	383	#define current_sgid() (current_cred_xxx(sgid))
	384	#define current_fsuid() (current_cred_xxx(fsuid))
	385	#define current_fsgid() (current_cred_xxx(fsgid))
	386	#define current_cap() (current_cred_xxx(cap_effective))
	387	#define current_user() (current_cred_xxx(user))
86a264ab	388
7e6bd8fa	389	extern struct user_namespace init_user_ns;
47a150ed	390	#ifdef CONFIG_USER_NS
f1c84dae	391	#define current_user_ns() (current_cred_xxx(user_ns))
47a150ed	392	#else
0335695d AB	393	static inline struct user_namespace *current_user_ns(void)
	394	{
	395	return &init_user_ns;
	396	}
47a150ed SH	397	#endif
47a150ed SH	398
3486740a	399
86a264ab DH	400	#define current_uid_gid(_uid, _gid) \
	401	do { \
	402	const struct cred *__cred; \
	403	__cred = current_cred(); \
	404	*(_uid) = __cred->uid; \
	405	*(_gid) = __cred->gid; \
	406	} while(0)
	407
	408	#define current_euid_egid(_euid, _egid) \
	409	do { \
	410	const struct cred *__cred; \
	411	__cred = current_cred(); \
	412	*(_euid) = __cred->euid; \
	413	*(_egid) = __cred->egid; \
	414	} while(0)
	415
	416	#define current_fsuid_fsgid(_fsuid, _fsgid) \
	417	do { \
	418	const struct cred *__cred; \
	419	__cred = current_cred(); \
	420	*(_fsuid) = __cred->fsuid; \
	421	*(_fsgid) = __cred->fsgid; \
	422	} while(0)
	423
9e2b2dc4	424	#endif /* _LINUX_CRED_H */