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1/* Authentication token and access key management
2 *
3 * Copyright (C) 2004, 2007 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 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>
21#include <linux/rcupdate.h>
22#include <linux/sysctl.h>
23#include <linux/rwsem.h>
24#include <asm/atomic.h>
25
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
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 */
45#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
46#define KEY_POS_ALL 0x3f000000
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
53#define KEY_USR_SETATTR 0x00200000
54#define KEY_USR_ALL 0x003f0000
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
61#define KEY_GRP_SETATTR 0x00002000
62#define KEY_GRP_ALL 0x00003f00
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
69#define KEY_OTH_SETATTR 0x00000020
70#define KEY_OTH_ALL 0x0000003f
71
72#define KEY_PERM_UNDEF 0xffffffff
73
74struct seq_file;
75struct user_struct;
76struct signal_struct;
77struct cred;
78
79struct key_type;
80struct key_owner;
81struct keyring_list;
82struct keyring_name;
83
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 */
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/*
118 * 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 */
129 struct rw_semaphore sem; /* change vs change sem */
130 struct key_user *user; /* owner of this key */
131 void *security; /* security data for this key */
132 time_t expiry; /* time at which key expires (or 0) */
133 uid_t uid;
134 gid_t gid;
135 key_perm_t perm; /* access permissions */
136 unsigned short quotalen; /* length added to quota */
137 unsigned short datalen; /* payload data length
138 * - may not match RCU dereferenced payload
139 * - payload should contain own length
140 */
141
142#ifdef KEY_DEBUGGING
143 unsigned magic;
144#define KEY_DEBUG_MAGIC 0x18273645u
145#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
146#endif
147
148 unsigned long flags; /* status flags (change with bitops) */
149#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
150#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
151#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
152#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
153#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
154#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
155
156 /* the description string
157 * - this is used to match a key against search criteria
158 * - this should be a printable string
159 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
160 */
161 char *description;
162
163 /* type specific data
164 * - this is used by the keyring type to index the name
165 */
166 union {
167 struct list_head link;
168 unsigned long x[2];
169 void *p[2];
170 } type_data;
171
172 /* key data
173 * - this is used to hold the data actually used in cryptography or
174 * whatever
175 */
176 union {
177 unsigned long value;
178 void *data;
179 struct keyring_list *subscriptions;
180 } payload;
181};
182
183extern struct key *key_alloc(struct key_type *type,
184 const char *desc,
185 uid_t uid, gid_t gid,
186 const struct cred *cred,
187 key_perm_t perm,
188 unsigned long flags);
189
190
191#define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
192#define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
193#define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
194
195extern void key_revoke(struct key *key);
196extern void key_put(struct key *key);
197
198static inline struct key *key_get(struct key *key)
199{
200 if (key)
201 atomic_inc(&key->usage);
202 return key;
203}
204
205static inline void key_ref_put(key_ref_t key_ref)
206{
207 key_put(key_ref_to_ptr(key_ref));
208}
209
210extern struct key *request_key(struct key_type *type,
211 const char *description,
212 const char *callout_info);
213
214extern struct key *request_key_with_auxdata(struct key_type *type,
215 const char *description,
216 const void *callout_info,
217 size_t callout_len,
218 void *aux);
219
220extern struct key *request_key_async(struct key_type *type,
221 const char *description,
222 const void *callout_info,
223 size_t callout_len);
224
225extern struct key *request_key_async_with_auxdata(struct key_type *type,
226 const char *description,
227 const void *callout_info,
228 size_t callout_len,
229 void *aux);
230
231extern int wait_for_key_construction(struct key *key, bool intr);
232
233extern int key_validate(struct key *key);
234
235extern key_ref_t key_create_or_update(key_ref_t keyring,
236 const char *type,
237 const char *description,
238 const void *payload,
239 size_t plen,
240 key_perm_t perm,
241 unsigned long flags);
242
243extern int key_update(key_ref_t key,
244 const void *payload,
245 size_t plen);
246
247extern int key_link(struct key *keyring,
248 struct key *key);
249
250extern int key_unlink(struct key *keyring,
251 struct key *key);
252
253extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
254 const struct cred *cred,
255 unsigned long flags,
256 struct key *dest);
257
258extern int keyring_clear(struct key *keyring);
259
260extern key_ref_t keyring_search(key_ref_t keyring,
261 struct key_type *type,
262 const char *description);
263
264extern int keyring_add_key(struct key *keyring,
265 struct key *key);
266
267extern struct key *key_lookup(key_serial_t id);
268
269static inline key_serial_t key_serial(struct key *key)
270{
271 return key ? key->serial : 0;
272}
273
274#ifdef CONFIG_SYSCTL
275extern ctl_table key_sysctls[];
276#endif
277
278/*
279 * the userspace interface
280 */
281extern int install_thread_keyring_to_cred(struct cred *cred);
282extern void key_fsuid_changed(struct task_struct *tsk);
283extern void key_fsgid_changed(struct task_struct *tsk);
284extern void key_init(void);
285
286#else /* CONFIG_KEYS */
287
288#define key_validate(k) 0
289#define key_serial(k) 0
290#define key_get(k) ({ NULL; })
291#define key_revoke(k) do { } while(0)
292#define key_put(k) do { } while(0)
293#define key_ref_put(k) do { } while(0)
294#define make_key_ref(k, p) NULL
295#define key_ref_to_ptr(k) NULL
296#define is_key_possessed(k) 0
297#define key_fsuid_changed(t) do { } while(0)
298#define key_fsgid_changed(t) do { } while(0)
299#define key_init() do { } while(0)
300
301#endif /* CONFIG_KEYS */
302#endif /* __KERNEL__ */
303#endif /* _LINUX_KEY_H */