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