Line data Source code
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 */
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 1 :
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 :
74 : struct seq_file;
75 : struct user_struct;
76 : struct signal_struct;
77 : struct cred;
78 :
79 : struct key_type;
80 : struct key_owner;
81 : struct keyring_list;
82 : struct 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 : */
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 :
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 */
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 : union {
133 : time_t expiry; /* time at which key expires (or 0) */
134 : time_t revoked_at; /* time at which key was revoked */
135 : };
136 : uid_t uid;
137 : gid_t gid;
138 : key_perm_t perm; /* access permissions */
139 : unsigned short quotalen; /* length added to quota */
140 : unsigned short datalen; /* payload data length
141 : * - may not match RCU dereferenced payload
142 : * - payload should contain own length
143 : */
144 :
145 : #ifdef KEY_DEBUGGING
146 : unsigned magic;
147 : #define KEY_DEBUG_MAGIC 0x18273645u
148 : #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
149 : #endif
150 :
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 :
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 "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;
171 : unsigned long x[2];
172 : void *p[2];
173 : } type_data;
174 :
175 : /* key data
176 : * - this is used to hold the data actually used in cryptography or
177 : * whatever
178 : */
179 : union {
180 : unsigned long value;
181 : void *data;
182 : struct keyring_list *subscriptions;
183 : } payload;
184 : };
185 :
186 : extern struct key *key_alloc(struct key_type *type,
187 : const char *desc,
188 : uid_t uid, gid_t gid,
189 : const struct cred *cred,
190 : key_perm_t perm,
191 : unsigned long flags);
192 :
193 :
194 : #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
195 : #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
196 : #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
197 :
198 : extern void key_revoke(struct key *key);
199 : extern void key_put(struct key *key);
200 :
201 : static inline struct key *key_get(struct key *key)
202 : {
203 : if (key)
204 : atomic_inc(&key->usage);
205 : return key;
206 : }
207 :
208 : static inline void key_ref_put(key_ref_t key_ref)
209 : {
210 : key_put(key_ref_to_ptr(key_ref));
211 : }
212 :
213 : extern struct key *request_key(struct key_type *type,
214 : const char *description,
215 : const char *callout_info);
216 :
217 : extern struct key *request_key_with_auxdata(struct key_type *type,
218 : const char *description,
219 : const void *callout_info,
220 : size_t callout_len,
221 : void *aux);
222 :
223 : extern struct key *request_key_async(struct key_type *type,
224 : const char *description,
225 : const void *callout_info,
226 : size_t callout_len);
227 :
228 : extern struct key *request_key_async_with_auxdata(struct key_type *type,
229 : const char *description,
230 : const void *callout_info,
231 : size_t callout_len,
232 : void *aux);
233 :
234 : extern int wait_for_key_construction(struct key *key, bool intr);
235 :
236 : extern int key_validate(struct key *key);
237 :
238 : extern key_ref_t key_create_or_update(key_ref_t keyring,
239 : const char *type,
240 : const char *description,
241 : const void *payload,
242 : size_t plen,
243 : key_perm_t perm,
244 : unsigned long flags);
245 :
246 : extern int key_update(key_ref_t key,
247 : const void *payload,
248 : size_t plen);
249 :
250 : extern int key_link(struct key *keyring,
251 : struct key *key);
252 :
253 : extern int key_unlink(struct key *keyring,
254 : struct key *key);
255 :
256 : extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
257 : const struct cred *cred,
258 : unsigned long flags,
259 : struct key *dest);
260 :
261 : extern int keyring_clear(struct key *keyring);
262 :
263 : extern key_ref_t keyring_search(key_ref_t keyring,
264 : struct key_type *type,
265 : const char *description);
266 :
267 : extern int keyring_add_key(struct key *keyring,
268 : struct key *key);
269 :
270 : extern struct key *key_lookup(key_serial_t id);
271 :
272 : static inline key_serial_t key_serial(struct key *key)
273 : {
274 : return key ? key->serial : 0;
275 : }
276 :
277 : #ifdef CONFIG_SYSCTL
278 : extern ctl_table key_sysctls[];
279 : #endif
280 :
281 : extern void key_replace_session_keyring(void);
282 :
283 : /*
284 : * the userspace interface
285 : */
286 : extern int install_thread_keyring_to_cred(struct cred *cred);
287 : extern void key_fsuid_changed(struct task_struct *tsk);
288 : extern void key_fsgid_changed(struct task_struct *tsk);
289 : extern void key_init(void);
290 :
291 : #else /* CONFIG_KEYS */
292 :
293 : #define key_validate(k) 0
294 : #define key_serial(k) 0
295 : #define key_get(k) ({ NULL; })
296 : #define key_revoke(k) do { } while(0)
297 : #define key_put(k) do { } while(0)
298 : #define key_ref_put(k) do { } while(0)
299 : #define make_key_ref(k, p) NULL
300 : #define key_ref_to_ptr(k) NULL
301 : #define is_key_possessed(k) 0
302 : #define key_fsuid_changed(t) do { } while(0)
303 : #define key_fsgid_changed(t) do { } while(0)
304 : #define key_init() do { } while(0)
305 : #define key_replace_session_keyring() do { } while(0)
306 :
307 : #endif /* CONFIG_KEYS */
308 : #endif /* __KERNEL__ */
309 : #endif /* _LINUX_KEY_H */
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