[linux.git] / include / linux / key.h

/* Authentication token and access key management
 *
 * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 *
 * See Documentation/keys.txt for information on keys/keyrings.
 */

#ifndef _LINUX_KEY_H
#define _LINUX_KEY_H

#include <linux/types.h>
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/rcupdate.h>
#include <linux/sysctl.h>
#include <linux/rwsem.h>
#include <asm/atomic.h>

#ifdef __KERNEL__

/* key handle serial number */
typedef int32_t key_serial_t;

/* key handle permissions mask */
typedef uint32_t key_perm_t;

struct key;

#ifdef CONFIG_KEYS

#undef KEY_DEBUGGING

#define KEY_POS_VIEW	0x01000000	/* possessor can view a key's attributes */
#define KEY_POS_READ	0x02000000	/* possessor can read key payload / view keyring */
#define KEY_POS_WRITE	0x04000000	/* possessor can update key payload / add link to keyring */
#define KEY_POS_SEARCH	0x08000000	/* possessor can find a key in search / search a keyring */
#define KEY_POS_LINK	0x10000000	/* possessor can create a link to a key/keyring */
#define KEY_POS_SETATTR	0x20000000	/* possessor can set key attributes */
#define KEY_POS_ALL	0x3f000000

#define KEY_USR_VIEW	0x00010000	/* user permissions... */
#define KEY_USR_READ	0x00020000
#define KEY_USR_WRITE	0x00040000
#define KEY_USR_SEARCH	0x00080000
#define KEY_USR_LINK	0x00100000
#define KEY_USR_SETATTR	0x00200000
#define KEY_USR_ALL	0x003f0000

#define KEY_GRP_VIEW	0x00000100	/* group permissions... */
#define KEY_GRP_READ	0x00000200
#define KEY_GRP_WRITE	0x00000400
#define KEY_GRP_SEARCH	0x00000800
#define KEY_GRP_LINK	0x00001000
#define KEY_GRP_SETATTR	0x00002000
#define KEY_GRP_ALL	0x00003f00

#define KEY_OTH_VIEW	0x00000001	/* third party permissions... */
#define KEY_OTH_READ	0x00000002
#define KEY_OTH_WRITE	0x00000004
#define KEY_OTH_SEARCH	0x00000008
#define KEY_OTH_LINK	0x00000010
#define KEY_OTH_SETATTR	0x00000020
#define KEY_OTH_ALL	0x0000003f

#define KEY_PERM_UNDEF	0xffffffff

struct seq_file;
struct user_struct;
struct signal_struct;
struct cred;

struct key_type;
struct key_owner;
struct keyring_list;
struct keyring_name;

/*****************************************************************************/
/*
 * key reference with possession attribute handling
 *
 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
 * defined. This is because we abuse the bottom bit of the reference to carry a
 * flag to indicate whether the calling process possesses that key in one of
 * its keyrings.
 *
 * the key_ref_t has been made a separate type so that the compiler can reject
 * attempts to dereference it without proper conversion.
 *
 * the three functions are used to assemble and disassemble references
 */
typedef struct __key_reference_with_attributes *key_ref_t;

static inline key_ref_t make_key_ref(const struct key *key,
				     unsigned long possession)
{
	return (key_ref_t) ((unsigned long) key | possession);
}

static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
{
	return (struct key *) ((unsigned long) key_ref & ~1UL);
}

static inline unsigned long is_key_possessed(const key_ref_t key_ref)
{
	return (unsigned long) key_ref & 1UL;
}

/*****************************************************************************/
/*
 * authentication token / access credential / keyring
 * - types of key include:
 *   - keyrings
 *   - disk encryption IDs
 *   - Kerberos TGTs and tickets
 */
struct key {
	atomic_t		usage;		/* number of references */
	key_serial_t		serial;		/* key serial number */
	struct rb_node		serial_node;
	struct key_type		*type;		/* type of key */
	struct rw_semaphore	sem;		/* change vs change sem */
	struct key_user		*user;		/* owner of this key */
	void			*security;	/* security data for this key */
	union {
		time_t		expiry;		/* time at which key expires (or 0) */
		time_t		revoked_at;	/* time at which key was revoked */
	};
	uid_t			uid;
	gid_t			gid;
	key_perm_t		perm;		/* access permissions */
	unsigned short		quotalen;	/* length added to quota */
	unsigned short		datalen;	/* payload data length
						 * - may not match RCU dereferenced payload
						 * - payload should contain own length
						 */

#ifdef KEY_DEBUGGING
	unsigned		magic;
#define KEY_DEBUG_MAGIC		0x18273645u
#define KEY_DEBUG_MAGIC_X	0xf8e9dacbu
#endif

	unsigned long		flags;		/* status flags (change with bitops) */
#define KEY_FLAG_INSTANTIATED	0	/* set if key has been instantiated */
#define KEY_FLAG_DEAD		1	/* set if key type has been deleted */
#define KEY_FLAG_REVOKED	2	/* set if key had been revoked */
#define KEY_FLAG_IN_QUOTA	3	/* set if key consumes quota */
#define KEY_FLAG_USER_CONSTRUCT	4	/* set if key is being constructed in userspace */
#define KEY_FLAG_NEGATIVE	5	/* set if key is negative */

	/* the description string
	 * - this is used to match a key against search criteria
	 * - this should be a printable string
	 * - eg: for krb5 AFS, this might be "[email protected]"
	 */
	char			*description;

	/* type specific data
	 * - this is used by the keyring type to index the name
	 */
	union {
		struct list_head	link;
		unsigned long		x[2];
		void			*p[2];
		int			reject_error;
	} type_data;

	/* key data
	 * - this is used to hold the data actually used in cryptography or
	 *   whatever
	 */
	union {
		unsigned long		value;
		void __rcu		*rcudata;
		void			*data;
		struct keyring_list __rcu *subscriptions;
	} payload;
};

extern struct key *key_alloc(struct key_type *type,
			     const char *desc,
			     uid_t uid, gid_t gid,
			     const struct cred *cred,
			     key_perm_t perm,
			     unsigned long flags);


#define KEY_ALLOC_IN_QUOTA	0x0000	/* add to quota, reject if would overrun */
#define KEY_ALLOC_QUOTA_OVERRUN	0x0001	/* add to quota, permit even if overrun */
#define KEY_ALLOC_NOT_IN_QUOTA	0x0002	/* not in quota */

extern void key_revoke(struct key *key);
extern void key_put(struct key *key);

static inline struct key *key_get(struct key *key)
{
	if (key)
		atomic_inc(&key->usage);
	return key;
}

static inline void key_ref_put(key_ref_t key_ref)
{
	key_put(key_ref_to_ptr(key_ref));
}

extern struct key *request_key(struct key_type *type,
			       const char *description,
			       const char *callout_info);

extern struct key *request_key_with_auxdata(struct key_type *type,
					    const char *description,
					    const void *callout_info,
					    size_t callout_len,
					    void *aux);

extern struct key *request_key_async(struct key_type *type,
				     const char *description,
				     const void *callout_info,
				     size_t callout_len);

extern struct key *request_key_async_with_auxdata(struct key_type *type,
						  const char *description,
						  const void *callout_info,
						  size_t callout_len,
						  void *aux);

extern int wait_for_key_construction(struct key *key, bool intr);

extern int key_validate(struct key *key);

extern key_ref_t key_create_or_update(key_ref_t keyring,
				      const char *type,
				      const char *description,
				      const void *payload,
				      size_t plen,
				      key_perm_t perm,
				      unsigned long flags);

extern int key_update(key_ref_t key,
		      const void *payload,
		      size_t plen);

extern int key_link(struct key *keyring,
		    struct key *key);

extern int key_unlink(struct key *keyring,
		      struct key *key);

extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
				 const struct cred *cred,
				 unsigned long flags,
				 struct key *dest);

extern int keyring_clear(struct key *keyring);

extern key_ref_t keyring_search(key_ref_t keyring,
				struct key_type *type,
				const char *description);

extern int keyring_add_key(struct key *keyring,
			   struct key *key);

extern struct key *key_lookup(key_serial_t id);

static inline key_serial_t key_serial(struct key *key)
{
	return key ? key->serial : 0;
}

#define rcu_dereference_key(KEY)					\
	(rcu_dereference_protected((KEY)->payload.rcudata,		\
				   rwsem_is_locked(&((struct key *)(KEY))->sem)))

#ifdef CONFIG_SYSCTL
extern ctl_table key_sysctls[];
#endif

extern void key_replace_session_keyring(void);

/*
 * the userspace interface
 */
extern int install_thread_keyring_to_cred(struct cred *cred);
extern void key_fsuid_changed(struct task_struct *tsk);
extern void key_fsgid_changed(struct task_struct *tsk);
extern void key_init(void);

#else /* CONFIG_KEYS */

#define key_validate(k)			0
#define key_serial(k)			0
#define key_get(k) 			({ NULL; })
#define key_revoke(k)			do { } while(0)
#define key_put(k)			do { } while(0)
#define key_ref_put(k)			do { } while(0)
#define make_key_ref(k, p)		NULL
#define key_ref_to_ptr(k)		NULL
#define is_key_possessed(k)		0
#define key_fsuid_changed(t)		do { } while(0)
#define key_fsgid_changed(t)		do { } while(0)
#define key_init()			do { } while(0)
#define key_replace_session_keyring()	do { } while(0)

#endif /* CONFIG_KEYS */
#endif /* __KERNEL__ */
#endif /* _LINUX_KEY_H */
Commit	Line	Data
76181c13	1	/* Authentication token and access key management
1da177e4	2	*
76181c13	3	* Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
1da177e4 LT	4	* Written by David Howells ([email protected])
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*
	11	*
	12	* See Documentation/keys.txt for information on keys/keyrings.
	13	*/
	14
	15	#ifndef _LINUX_KEY_H
	16	#define _LINUX_KEY_H
	17
	18	#include <linux/types.h>
	19	#include <linux/list.h>
	20	#include <linux/rbtree.h>
76d8aeab	21	#include <linux/rcupdate.h>
0b77f5bf	22	#include <linux/sysctl.h>
aa84442d	23	#include <linux/rwsem.h>
1da177e4 LT	24	#include <asm/atomic.h>
	25
	26	#ifdef __KERNEL__
	27
	28	/* key handle serial number */
	29	typedef int32_t key_serial_t;
	30
	31	/* key handle permissions mask */
	32	typedef uint32_t key_perm_t;
	33
	34	struct key;
	35
	36	#ifdef CONFIG_KEYS
	37
	38	#undef KEY_DEBUGGING
	39
664cceb0 DH	40	#define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
	41	#define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
	42	#define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
	43	#define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
	44	#define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
29db9190 DH	45	#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
29db9190 DH	46	#define KEY_POS_ALL 0x3f000000
664cceb0 DH	47
	48	#define KEY_USR_VIEW 0x00010000 /* user permissions... */
	49	#define KEY_USR_READ 0x00020000
	50	#define KEY_USR_WRITE 0x00040000
	51	#define KEY_USR_SEARCH 0x00080000
	52	#define KEY_USR_LINK 0x00100000
29db9190 DH	53	#define KEY_USR_SETATTR 0x00200000
29db9190 DH	54	#define KEY_USR_ALL 0x003f0000
1da177e4 LT	55
	56	#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
	57	#define KEY_GRP_READ 0x00000200
	58	#define KEY_GRP_WRITE 0x00000400
	59	#define KEY_GRP_SEARCH 0x00000800
	60	#define KEY_GRP_LINK 0x00001000
29db9190 DH	61	#define KEY_GRP_SETATTR 0x00002000
29db9190 DH	62	#define KEY_GRP_ALL 0x00003f00
1da177e4 LT	63
	64	#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
	65	#define KEY_OTH_READ 0x00000002
	66	#define KEY_OTH_WRITE 0x00000004
	67	#define KEY_OTH_SEARCH 0x00000008
	68	#define KEY_OTH_LINK 0x00000010
29db9190 DH	69	#define KEY_OTH_SETATTR 0x00000020
29db9190 DH	70	#define KEY_OTH_ALL 0x0000003f
1da177e4	71
6b79ccb5 AR	72	#define KEY_PERM_UNDEF 0xffffffff
6b79ccb5 AR	73
1da177e4 LT	74	struct seq_file;
	75	struct user_struct;
	76	struct signal_struct;
d84f4f99	77	struct cred;
1da177e4 LT	78
	79	struct key_type;
	80	struct key_owner;
	81	struct keyring_list;
	82	struct keyring_name;
	83
664cceb0 DH	84	/*****************************************************************************/
	85	/*
	86	* key reference with possession attribute handling
	87	*
	88	* NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
	89	* defined. This is because we abuse the bottom bit of the reference to carry a
	90	* flag to indicate whether the calling process possesses that key in one of
	91	* its keyrings.
	92	*
	93	* the key_ref_t has been made a separate type so that the compiler can reject
	94	* attempts to dereference it without proper conversion.
	95	*
	96	* the three functions are used to assemble and disassemble references
	97	*/
	98	typedef struct __key_reference_with_attributes *key_ref_t;
	99
	100	static inline key_ref_t make_key_ref(const struct key *key,
	101	unsigned long possession)
	102	{
	103	return (key_ref_t) ((unsigned long) key \| possession);
	104	}
	105
	106	static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
	107	{
	108	return (struct key *) ((unsigned long) key_ref & ~1UL);
	109	}
	110
	111	static inline unsigned long is_key_possessed(const key_ref_t key_ref)
	112	{
	113	return (unsigned long) key_ref & 1UL;
	114	}
	115
1da177e4 LT	116	/*****************************************************************************/
	117	/*
	118	* authentication token / access credential / keyring
	119	* - types of key include:
	120	* - keyrings
	121	* - disk encryption IDs
	122	* - Kerberos TGTs and tickets
	123	*/
	124	struct key {
	125	atomic_t usage; /* number of references */
	126	key_serial_t serial; /* key serial number */
	127	struct rb_node serial_node;
	128	struct key_type type; / type of key */
1da177e4 LT	129	struct rw_semaphore sem; /* change vs change sem */
1da177e4 LT	130	struct key_user user; / owner of this key */
29db9190	131	void security; / security data for this key */
5d135440 DH	132	union {
	133	time_t expiry; /* time at which key expires (or 0) */
	134	time_t revoked_at; /* time at which key was revoked */
	135	};
1da177e4 LT	136	uid_t uid;
	137	gid_t gid;
	138	key_perm_t perm; /* access permissions */
	139	unsigned short quotalen; /* length added to quota */
76d8aeab DH	140	unsigned short datalen; /* payload data length
	141	* - may not match RCU dereferenced payload
	142	* - payload should contain own length
	143	*/
1da177e4 LT	144
	145	#ifdef KEY_DEBUGGING
	146	unsigned magic;
	147	#define KEY_DEBUG_MAGIC 0x18273645u
	148	#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
	149	#endif
	150
76d8aeab DH	151	unsigned long flags; /* status flags (change with bitops) */
	152	#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
	153	#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
	154	#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
	155	#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
	156	#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
	157	#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
	158
1da177e4 LT	159	/* the description string
	160	* - this is used to match a key against search criteria
	161	* - this should be a printable string
	162	* - eg: for krb5 AFS, this might be "[email protected]"
	163	*/
	164	char *description;
	165
	166	/* type specific data
	167	* - this is used by the keyring type to index the name
	168	*/
	169	union {
	170	struct list_head link;
7318226e DH	171	unsigned long x[2];
7318226e DH	172	void *p[2];
fdd1b945	173	int reject_error;
1da177e4 LT	174	} type_data;
	175
	176	/* key data
	177	* - this is used to hold the data actually used in cryptography or
	178	* whatever
	179	*/
	180	union {
	181	unsigned long value;
e63ba744	182	void __rcu *rcudata;
1da177e4	183	void *data;
e63ba744	184	struct keyring_list __rcu *subscriptions;
1da177e4 LT	185	} payload;
	186	};
	187
1da177e4 LT	188	extern struct key key_alloc(struct key_type type,
1da177e4 LT	189	const char *desc,
d720024e	190	uid_t uid, gid_t gid,
d84f4f99	191	const struct cred *cred,
7e047ef5 DH	192	key_perm_t perm,
	193	unsigned long flags);
	194
	195
	196	#define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
	197	#define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
	198	#define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
	199
1da177e4 LT	200	extern void key_revoke(struct key *key);
	201	extern void key_put(struct key *key);
	202
	203	static inline struct key key_get(struct key key)
	204	{
	205	if (key)
	206	atomic_inc(&key->usage);
	207	return key;
	208	}
	209
664cceb0 DH	210	static inline void key_ref_put(key_ref_t key_ref)
	211	{
	212	key_put(key_ref_to_ptr(key_ref));
	213	}
	214
1da177e4 LT	215	extern struct key request_key(struct key_type type,
	216	const char *description,
	217	const char *callout_info);
	218
4e54f085 DH	219	extern struct key request_key_with_auxdata(struct key_type type,
4e54f085 DH	220	const char *description,
4a38e122 DH	221	const void *callout_info,
4a38e122 DH	222	size_t callout_len,
4e54f085 DH	223	void *aux);
4e54f085 DH	224
76181c13 DH	225	extern struct key request_key_async(struct key_type type,
76181c13 DH	226	const char *description,
4a38e122 DH	227	const void *callout_info,
4a38e122 DH	228	size_t callout_len);
76181c13 DH	229
	230	extern struct key request_key_async_with_auxdata(struct key_type type,
	231	const char *description,
4a38e122 DH	232	const void *callout_info,
4a38e122 DH	233	size_t callout_len,
76181c13 DH	234	void *aux);
	235
	236	extern int wait_for_key_construction(struct key *key, bool intr);
	237
1da177e4 LT	238	extern int key_validate(struct key *key);
1da177e4 LT	239
664cceb0 DH	240	extern key_ref_t key_create_or_update(key_ref_t keyring,
	241	const char *type,
	242	const char *description,
	243	const void *payload,
	244	size_t plen,
6b79ccb5	245	key_perm_t perm,
7e047ef5	246	unsigned long flags);
1da177e4	247
664cceb0	248	extern int key_update(key_ref_t key,
1da177e4 LT	249	const void *payload,
	250	size_t plen);
	251
	252	extern int key_link(struct key *keyring,
	253	struct key *key);
	254
	255	extern int key_unlink(struct key *keyring,
	256	struct key *key);
	257
	258	extern struct key keyring_alloc(const char description, uid_t uid, gid_t gid,
d84f4f99	259	const struct cred *cred,
7e047ef5	260	unsigned long flags,
d720024e	261	struct key *dest);
1da177e4 LT	262
	263	extern int keyring_clear(struct key *keyring);
	264
664cceb0 DH	265	extern key_ref_t keyring_search(key_ref_t keyring,
	266	struct key_type *type,
	267	const char *description);
1da177e4	268
1da177e4 LT	269	extern int keyring_add_key(struct key *keyring,
	270	struct key *key);
	271
	272	extern struct key *key_lookup(key_serial_t id);
	273
7249db2c DH	274	static inline key_serial_t key_serial(struct key *key)
	275	{
	276	return key ? key->serial : 0;
	277	}
1da177e4	278
633e804e DH	279	#define rcu_dereference_key(KEY) \
	280	(rcu_dereference_protected((KEY)->payload.rcudata, \
	281	rwsem_is_locked(&((struct key *)(KEY))->sem)))
	282
0b77f5bf DH	283	#ifdef CONFIG_SYSCTL
	284	extern ctl_table key_sysctls[];
	285	#endif
	286
ee18d64c DH	287	extern void key_replace_session_keyring(void);
ee18d64c DH	288
1da177e4 LT	289	/*
	290	* the userspace interface
	291	*/
d84f4f99	292	extern int install_thread_keyring_to_cred(struct cred *cred);
1da177e4 LT	293	extern void key_fsuid_changed(struct task_struct *tsk);
	294	extern void key_fsgid_changed(struct task_struct *tsk);
	295	extern void key_init(void);
	296
	297	#else /* CONFIG_KEYS */
	298
	299	#define key_validate(k) 0
	300	#define key_serial(k) 0
7888e7ff	301	#define key_get(k) ({ NULL; })
0dab9cfa	302	#define key_revoke(k) do { } while(0)
1da177e4	303	#define key_put(k) do { } while(0)
664cceb0	304	#define key_ref_put(k) do { } while(0)
8bbf4976 DH	305	#define make_key_ref(k, p) NULL
8bbf4976 DH	306	#define key_ref_to_ptr(k) NULL
664cceb0	307	#define is_key_possessed(k) 0
1da177e4 LT	308	#define key_fsuid_changed(t) do { } while(0)
	309	#define key_fsgid_changed(t) do { } while(0)
	310	#define key_init() do { } while(0)
ee18d64c	311	#define key_replace_session_keyring() do { } while(0)
1da177e4 LT	312
	313	#endif /* CONFIG_KEYS */
	314	#endif /* __KERNEL__ */
	315	#endif /* _LINUX_KEY_H */