[net-next-2.6.git] / include / linux / cred.h

/* Credentials management
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#ifndef _LINUX_CRED_H
#define _LINUX_CRED_H

#include <linux/capability.h>
#include <linux/key.h>
#include <asm/atomic.h>

struct user_struct;
struct cred;

/*
 * COW Supplementary groups list
 */
#define NGROUPS_SMALL		32
#define NGROUPS_PER_BLOCK	((unsigned int)(PAGE_SIZE / sizeof(gid_t)))

struct group_info {
	atomic_t	usage;
	int		ngroups;
	int		nblocks;
	gid_t		small_block[NGROUPS_SMALL];
	gid_t		*blocks[0];
};

/**
 * 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)

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(const struct group_info *, gid_t);

/* access the groups "array" with this macro */
#define GROUP_AT(gi, i) \
	((gi)->blocks[(i) / NGROUPS_PER_BLOCK][(i) % NGROUPS_PER_BLOCK])

extern int in_group_p(gid_t);
extern int in_egroup_p(gid_t);

/*
 * 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;
	uid_t		uid;		/* real UID of the task */
	gid_t		gid;		/* real GID of the task */
	uid_t		suid;		/* saved UID of the task */
	gid_t		sgid;		/* saved GID of the task */
	uid_t		euid;		/* effective UID of the task */
	gid_t		egid;		/* effective GID of the task */
	uid_t		fsuid;		/* UID for VFS ops */
	gid_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 */
#ifdef CONFIG_KEYS
	unsigned char	jit_keyring;	/* default keyring to attach requested
					 * keys to */
	struct key	*thread_keyring; /* keyring private to this thread */
	struct key	*request_key_auth; /* assumed request_key authority */
#endif
#ifdef CONFIG_SECURITY
	void		*security;	/* subjective LSM security */
#endif
	struct user_struct *user;	/* real user ID subscription */
	struct group_info *group_info;	/* supplementary groups for euid/fsgid */
	struct rcu_head	rcu;		/* RCU deletion hook */
	spinlock_t	lock;		/* lock for pointer changes */
};

extern void __put_cred(struct cred *);
extern int copy_creds(struct task_struct *, unsigned long);

/**
 * 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.
 */
static inline struct cred *get_cred(struct cred *cred)
{
	atomic_inc(&cred->usage);
	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.
 */
static inline void put_cred(struct cred *cred)
{
	if (atomic_dec_and_test(&(cred)->usage))
		__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 */
Commit	Line	Data
9e2b2dc4 DH	1	/* Credentials management
	2	*
	3	* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11
	12	#ifndef _LINUX_CRED_H
	13	#define _LINUX_CRED_H
	14
b6dff3ec DH	15	#include <linux/capability.h>
	16	#include <linux/key.h>
	17	#include <asm/atomic.h>
	18
	19	struct user_struct;
	20	struct cred;
	21
	22	/*
	23	* COW Supplementary groups list
	24	*/
	25	#define NGROUPS_SMALL 32
	26	#define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(gid_t)))
	27
	28	struct group_info {
	29	atomic_t usage;
	30	int ngroups;
	31	int nblocks;
	32	gid_t small_block[NGROUPS_SMALL];
	33	gid_t *blocks[0];
	34	};
	35
	36	/**
	37	* get_group_info - Get a reference to a group info structure
	38	* @group_info: The group info to reference
	39	*
86a264ab DH	40	* This gets a reference to a set of supplementary groups.
	41	*
	42	* If the caller is accessing a task's credentials, they must hold the RCU read
	43	* lock when reading.
b6dff3ec	44	*/
86a264ab DH	45	static inline struct group_info get_group_info(struct group_info gi)
	46	{
	47	atomic_inc(&gi->usage);
	48	return gi;
	49	}
b6dff3ec DH	50
	51	/**
	52	* put_group_info - Release a reference to a group info structure
	53	* @group_info: The group info to release
	54	*/
	55	#define put_group_info(group_info) \
	56	do { \
	57	if (atomic_dec_and_test(&(group_info)->usage)) \
	58	groups_free(group_info); \
	59	} while (0)
	60
	61	extern struct group_info *groups_alloc(int);
	62	extern void groups_free(struct group_info *);
	63	extern int set_current_groups(struct group_info *);
	64	extern int set_groups(struct cred , struct group_info );
86a264ab	65	extern int groups_search(const struct group_info *, gid_t);
b6dff3ec DH	66
	67	/* access the groups "array" with this macro */
	68	#define GROUP_AT(gi, i) \
	69	((gi)->blocks[(i) / NGROUPS_PER_BLOCK][(i) % NGROUPS_PER_BLOCK])
	70
	71	extern int in_group_p(gid_t);
	72	extern int in_egroup_p(gid_t);
	73
	74	/*
	75	* The security context of a task
	76	*
	77	* The parts of the context break down into two categories:
	78	*
	79	* (1) The objective context of a task. These parts are used when some other
	80	* task is attempting to affect this one.
	81	*
	82	* (2) The subjective context. These details are used when the task is acting
	83	* upon another object, be that a file, a task, a key or whatever.
	84	*
	85	* Note that some members of this structure belong to both categories - the
	86	* LSM security pointer for instance.
	87	*
	88	* A task has two security pointers. task->real_cred points to the objective
	89	* context that defines that task's actual details. The objective part of this
	90	* context is used whenever that task is acted upon.
	91	*
	92	* task->cred points to the subjective context that defines the details of how
	93	* that task is going to act upon another object. This may be overridden
	94	* temporarily to point to another security context, but normally points to the
	95	* same context as task->real_cred.
	96	*/
	97	struct cred {
	98	atomic_t usage;
	99	uid_t uid; /* real UID of the task */
	100	gid_t gid; /* real GID of the task */
	101	uid_t suid; /* saved UID of the task */
	102	gid_t sgid; /* saved GID of the task */
	103	uid_t euid; /* effective UID of the task */
	104	gid_t egid; /* effective GID of the task */
	105	uid_t fsuid; /* UID for VFS ops */
	106	gid_t fsgid; /* GID for VFS ops */
	107	unsigned securebits; /* SUID-less security management */
	108	kernel_cap_t cap_inheritable; /* caps our children can inherit */
	109	kernel_cap_t cap_permitted; /* caps we're permitted */
	110	kernel_cap_t cap_effective; /* caps we can actually use */
	111	kernel_cap_t cap_bset; /* capability bounding set */
	112	#ifdef CONFIG_KEYS
	113	unsigned char jit_keyring; /* default keyring to attach requested
	114	* keys to */
	115	struct key thread_keyring; / keyring private to this thread */
	116	struct key request_key_auth; / assumed request_key authority */
	117	#endif
	118	#ifdef CONFIG_SECURITY
	119	void security; / subjective LSM security */
	120	#endif
	121	struct user_struct user; / real user ID subscription */
	122	struct group_info group_info; / supplementary groups for euid/fsgid */
	123	struct rcu_head rcu; /* RCU deletion hook */
	124	spinlock_t lock; /* lock for pointer changes */
	125	};
	126
f1752eec DH	127	extern void __put_cred(struct cred *);
	128	extern int copy_creds(struct task_struct *, unsigned long);
	129
	130	/**
	131	* get_cred - Get a reference on a set of credentials
	132	* @cred: The credentials to reference
	133	*
	134	* Get a reference on the specified set of credentials. The caller must
	135	* release the reference.
	136	*/
	137	static inline struct cred get_cred(struct cred cred)
	138	{
	139	atomic_inc(&cred->usage);
	140	return cred;
	141	}
	142
	143	/**
	144	* put_cred - Release a reference to a set of credentials
	145	* @cred: The credentials to release
	146	*
	147	* Release a reference to a set of credentials, deleting them when the last ref
	148	* is released.
	149	*/
	150	static inline void put_cred(struct cred *cred)
	151	{
	152	if (atomic_dec_and_test(&(cred)->usage))
	153	__put_cred(cred);
	154	}
	155
86a264ab DH	156	/**
	157	* current_cred - Access the current task's credentials
	158	*
	159	* Access the credentials of the current task.
	160	*/
	161	#define current_cred() \
	162	(current->cred)
	163
	164	/**
	165	* __task_cred - Access another task's credentials
	166	* @task: The task to query
	167	*
	168	* Access the credentials of another task. The caller must hold the
	169	* RCU readlock.
	170	*
	171	* The caller must make sure task doesn't go away, either by holding a ref on
	172	* task or by holding tasklist_lock to prevent it from being unlinked.
	173	*/
	174	#define __task_cred(task) \
	175	((const struct cred *)(rcu_dereference((task)->cred)))
	176
	177	/**
	178	* get_task_cred - Get another task's credentials
	179	* @task: The task to query
	180	*
	181	* Get the credentials of a task, pinning them so that they can't go away.
	182	* Accessing a task's credentials directly is not permitted.
	183	*
	184	* The caller must make sure task doesn't go away, either by holding a ref on
	185	* task or by holding tasklist_lock to prevent it from being unlinked.
	186	*/
	187	#define get_task_cred(task) \
	188	({ \
	189	struct cred *__cred; \
	190	rcu_read_lock(); \
	191	__cred = (struct cred *) __task_cred((task)); \
	192	get_cred(__cred); \
	193	rcu_read_unlock(); \
	194	__cred; \
	195	})
	196
	197	/**
	198	* get_current_cred - Get the current task's credentials
	199	*
	200	* Get the credentials of the current task, pinning them so that they can't go
	201	* away. Accessing the current task's credentials directly is not permitted.
	202	*/
	203	#define get_current_cred() \
	204	(get_cred(current_cred()))
	205
	206	/**
	207	* get_current_user - Get the current task's user_struct
	208	*
	209	* Get the user record of the current task, pinning it so that it can't go
	210	* away.
	211	*/
	212	#define get_current_user() \
	213	({ \
	214	struct user_struct *__u; \
	215	struct cred *__cred; \
	216	__cred = (struct cred *) current_cred(); \
	217	__u = get_uid(__cred->user); \
	218	__u; \
	219	})
220
221	/**
222	* get_current_groups - Get the current task's supplementary group list
223	*
224	* Get the supplementary group list of the current task, pinning it so that it
225	* can't go away.
226	*/
227	#define get_current_groups() \
228	({ \
229	struct group_info *__groups; \
230	struct cred *__cred; \
231	__cred = (struct cred *) current_cred(); \
232	__groups = get_group_info(__cred->group_info); \
233	__groups; \
234	})
235
236	#define task_cred_xxx(task, xxx) \
237	({ \
238	__typeof__(task->cred->xxx) ___val; \
239	rcu_read_lock(); \
240	___val = __task_cred((task))->xxx; \
241	rcu_read_unlock(); \
242	___val; \
243	})
244
245	#define task_uid(task) (task_cred_xxx((task), uid))
246	#define task_euid(task) (task_cred_xxx((task), euid))
247
248	#define current_cred_xxx(xxx) \
249	({ \
250	current->cred->xxx; \
251	})
252
253	#define current_uid() (current_cred_xxx(uid))
254	#define current_gid() (current_cred_xxx(gid))
255	#define current_euid() (current_cred_xxx(euid))
256	#define current_egid() (current_cred_xxx(egid))
257	#define current_suid() (current_cred_xxx(suid))
258	#define current_sgid() (current_cred_xxx(sgid))
259	#define current_fsuid() (current_cred_xxx(fsuid))
260	#define current_fsgid() (current_cred_xxx(fsgid))
261	#define current_cap() (current_cred_xxx(cap_effective))
262	#define current_user() (current_cred_xxx(user))
263	#define current_security() (current_cred_xxx(security))
264
265	#define current_uid_gid(_uid, _gid) \
266	do { \
267	const struct cred *__cred; \
268	__cred = current_cred(); \
269	*(_uid) = __cred->uid; \
270	*(_gid) = __cred->gid; \
271	} while(0)
272
273	#define current_euid_egid(_euid, _egid) \
274	do { \
275	const struct cred *__cred; \
276	__cred = current_cred(); \
277	*(_euid) = __cred->euid; \
278	*(_egid) = __cred->egid; \
279	} while(0)
280
281	#define current_fsuid_fsgid(_fsuid, _fsgid) \
282	do { \
283	const struct cred *__cred; \
284	__cred = current_cred(); \
285	*(_fsuid) = __cred->fsuid; \
286	*(_fsgid) = __cred->fsgid; \
287	} while(0)
288
9e2b2dc4	289	#endif /* _LINUX_CRED_H */