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David Howells76181c12007-10-16 23:29:46 -07001/* Authentication token and access key management
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
David Howells76181c12007-10-16 23:29:46 -07003 * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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 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 *
Randy Dunlapd410fa42011-05-19 15:59:38 -070012 * See Documentation/security/keys.txt for information on keys/keyrings.
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 */
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>
David Howells76d8aea2005-06-23 22:00:49 -070021#include <linux/rcupdate.h>
David Howells0b77f5b2008-04-29 01:01:32 -070022#include <linux/sysctl.h>
Pekka Enbergaa844422009-03-24 10:54:46 +020023#include <linux/rwsem.h>
Arun Sharma600634972011-07-26 16:09:06 -070024#include <linux/atomic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26#ifdef __KERNEL__
27
28/* key handle serial number */
29typedef int32_t key_serial_t;
30
31/* key handle permissions mask */
32typedef uint32_t key_perm_t;
33
34struct key;
35
36#ifdef CONFIG_KEYS
37
38#undef KEY_DEBUGGING
39
David Howells664cceb2005-09-28 17:03:15 +010040#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 */
David Howells29db9192005-10-30 15:02:44 -080045#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
46#define KEY_POS_ALL 0x3f000000
David Howells664cceb2005-09-28 17:03:15 +010047
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
David Howells29db9192005-10-30 15:02:44 -080053#define KEY_USR_SETATTR 0x00200000
54#define KEY_USR_ALL 0x003f0000
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
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
David Howells29db9192005-10-30 15:02:44 -080061#define KEY_GRP_SETATTR 0x00002000
62#define KEY_GRP_ALL 0x00003f00
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
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
David Howells29db9192005-10-30 15:02:44 -080069#define KEY_OTH_SETATTR 0x00000020
70#define KEY_OTH_ALL 0x0000003f
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Arun Raghavan6b79ccb2008-04-29 01:01:28 -070072#define KEY_PERM_UNDEF 0xffffffff
73
Linus Torvalds1da177e2005-04-16 15:20:36 -070074struct seq_file;
75struct user_struct;
76struct signal_struct;
David Howellsd84f4f92008-11-14 10:39:23 +110077struct cred;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79struct key_type;
80struct key_owner;
81struct keyring_list;
82struct keyring_name;
83
84/*****************************************************************************/
85/*
David Howells664cceb2005-09-28 17:03:15 +010086 * 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 */
98typedef struct __key_reference_with_attributes *key_ref_t;
99
100static 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
106static 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
111static inline unsigned long is_key_possessed(const key_ref_t key_ref)
112{
113 return (unsigned long) key_ref & 1UL;
114}
115
116/*****************************************************************************/
117/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 * authentication token / access credential / keyring
119 * - types of key include:
120 * - keyrings
121 * - disk encryption IDs
122 * - Kerberos TGTs and tickets
123 */
124struct 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 struct rw_semaphore sem; /* change vs change sem */
130 struct key_user *user; /* owner of this key */
David Howells29db9192005-10-30 15:02:44 -0800131 void *security; /* security data for this key */
David Howells5d135442009-09-02 09:14:00 +0100132 union {
133 time_t expiry; /* time at which key expires (or 0) */
134 time_t revoked_at; /* time at which key was revoked */
135 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 uid_t uid;
137 gid_t gid;
138 key_perm_t perm; /* access permissions */
139 unsigned short quotalen; /* length added to quota */
David Howells76d8aea2005-06-23 22:00:49 -0700140 unsigned short datalen; /* payload data length
141 * - may not match RCU dereferenced payload
142 * - payload should contain own length
143 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145#ifdef KEY_DEBUGGING
146 unsigned magic;
147#define KEY_DEBUG_MAGIC 0x18273645u
148#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
149#endif
150
David Howells76d8aea2005-06-23 22:00:49 -0700151 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 /* 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 "afs@REDHAT.COM"
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;
David Howells73182262007-04-26 15:46:23 -0700171 unsigned long x[2];
172 void *p[2];
David Howellsfdd1b942011-03-07 15:06:09 +0000173 int reject_error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 } 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;
Arnd Bergmanne63ba742010-02-26 18:01:20 +0100182 void __rcu *rcudata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 void *data;
Arnd Bergmanne63ba742010-02-26 18:01:20 +0100184 struct keyring_list __rcu *subscriptions;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 } payload;
186};
187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188extern struct key *key_alloc(struct key_type *type,
189 const char *desc,
Michael LeMayd7200242006-06-22 14:47:17 -0700190 uid_t uid, gid_t gid,
David Howellsd84f4f92008-11-14 10:39:23 +1100191 const struct cred *cred,
David Howells7e047ef2006-06-26 00:24:50 -0700192 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200extern void key_revoke(struct key *key);
201extern void key_put(struct key *key);
202
203static inline struct key *key_get(struct key *key)
204{
205 if (key)
206 atomic_inc(&key->usage);
207 return key;
208}
209
David Howells664cceb2005-09-28 17:03:15 +0100210static inline void key_ref_put(key_ref_t key_ref)
211{
212 key_put(key_ref_to_ptr(key_ref));
213}
214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215extern struct key *request_key(struct key_type *type,
216 const char *description,
217 const char *callout_info);
218
David Howells4e54f082006-06-29 02:24:28 -0700219extern struct key *request_key_with_auxdata(struct key_type *type,
220 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700221 const void *callout_info,
222 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700223 void *aux);
224
David Howells76181c12007-10-16 23:29:46 -0700225extern struct key *request_key_async(struct key_type *type,
226 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700227 const void *callout_info,
228 size_t callout_len);
David Howells76181c12007-10-16 23:29:46 -0700229
230extern struct key *request_key_async_with_auxdata(struct key_type *type,
231 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700232 const void *callout_info,
233 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700234 void *aux);
235
236extern int wait_for_key_construction(struct key *key, bool intr);
237
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238extern int key_validate(struct key *key);
239
David Howells664cceb2005-09-28 17:03:15 +0100240extern 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,
Arun Raghavan6b79ccb2008-04-29 01:01:28 -0700245 key_perm_t perm,
David Howells7e047ef2006-06-26 00:24:50 -0700246 unsigned long flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247
David Howells664cceb2005-09-28 17:03:15 +0100248extern int key_update(key_ref_t key,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 const void *payload,
250 size_t plen);
251
252extern int key_link(struct key *keyring,
253 struct key *key);
254
255extern int key_unlink(struct key *keyring,
256 struct key *key);
257
258extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
David Howellsd84f4f92008-11-14 10:39:23 +1100259 const struct cred *cred,
David Howells7e047ef2006-06-26 00:24:50 -0700260 unsigned long flags,
Michael LeMayd7200242006-06-22 14:47:17 -0700261 struct key *dest);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
263extern int keyring_clear(struct key *keyring);
264
David Howells664cceb2005-09-28 17:03:15 +0100265extern key_ref_t keyring_search(key_ref_t keyring,
266 struct key_type *type,
267 const char *description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269extern int keyring_add_key(struct key *keyring,
270 struct key *key);
271
272extern struct key *key_lookup(key_serial_t id);
273
David Howells7249db22008-04-29 01:01:34 -0700274static inline key_serial_t key_serial(struct key *key)
275{
276 return key ? key->serial : 0;
277}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278
David Howells78b72802011-03-11 17:57:23 +0000279/**
280 * key_is_instantiated - Determine if a key has been positively instantiated
281 * @key: The key to check.
282 *
283 * Return true if the specified key has been positively instantiated, false
284 * otherwise.
285 */
286static inline bool key_is_instantiated(const struct key *key)
287{
288 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
289 !test_bit(KEY_FLAG_NEGATIVE, &key->flags);
290}
291
David Howells633e8042011-03-07 15:05:51 +0000292#define rcu_dereference_key(KEY) \
293 (rcu_dereference_protected((KEY)->payload.rcudata, \
294 rwsem_is_locked(&((struct key *)(KEY))->sem)))
295
David Howells0b77f5b2008-04-29 01:01:32 -0700296#ifdef CONFIG_SYSCTL
297extern ctl_table key_sysctls[];
298#endif
299
David Howellsee18d642009-09-02 09:14:21 +0100300extern void key_replace_session_keyring(void);
301
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302/*
303 * the userspace interface
304 */
David Howellsd84f4f92008-11-14 10:39:23 +1100305extern int install_thread_keyring_to_cred(struct cred *cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306extern void key_fsuid_changed(struct task_struct *tsk);
307extern void key_fsgid_changed(struct task_struct *tsk);
308extern void key_init(void);
309
310#else /* CONFIG_KEYS */
311
312#define key_validate(k) 0
313#define key_serial(k) 0
David Howells7888e7f2005-06-23 22:00:51 -0700314#define key_get(k) ({ NULL; })
Adrian Bunk0dab9cf2008-10-12 07:10:50 +0300315#define key_revoke(k) do { } while(0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316#define key_put(k) do { } while(0)
David Howells664cceb2005-09-28 17:03:15 +0100317#define key_ref_put(k) do { } while(0)
David Howells8bbf49762008-11-14 10:39:14 +1100318#define make_key_ref(k, p) NULL
319#define key_ref_to_ptr(k) NULL
David Howells664cceb2005-09-28 17:03:15 +0100320#define is_key_possessed(k) 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321#define key_fsuid_changed(t) do { } while(0)
322#define key_fsgid_changed(t) do { } while(0)
323#define key_init() do { } while(0)
David Howellsee18d642009-09-02 09:14:21 +0100324#define key_replace_session_keyring() do { } while(0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326#endif /* CONFIG_KEYS */
327#endif /* __KERNEL__ */
328#endif /* _LINUX_KEY_H */