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TOMOYO Linux Cross Reference
Linux/include/linux/key.h

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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/security/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 <linux/atomic.h>
 25 #include <linux/assoc_array.h>
 26 
 27 #ifdef __KERNEL__
 28 #include <linux/uidgid.h>
 29 
 30 /* key handle serial number */
 31 typedef int32_t key_serial_t;
 32 
 33 /* key handle permissions mask */
 34 typedef uint32_t key_perm_t;
 35 
 36 struct key;
 37 
 38 #ifdef CONFIG_KEYS
 39 
 40 #undef KEY_DEBUGGING
 41 
 42 #define KEY_POS_VIEW    0x01000000      /* possessor can view a key's attributes */
 43 #define KEY_POS_READ    0x02000000      /* possessor can read key payload / view keyring */
 44 #define KEY_POS_WRITE   0x04000000      /* possessor can update key payload / add link to keyring */
 45 #define KEY_POS_SEARCH  0x08000000      /* possessor can find a key in search / search a keyring */
 46 #define KEY_POS_LINK    0x10000000      /* possessor can create a link to a key/keyring */
 47 #define KEY_POS_SETATTR 0x20000000      /* possessor can set key attributes */
 48 #define KEY_POS_ALL     0x3f000000
 49 
 50 #define KEY_USR_VIEW    0x00010000      /* user permissions... */
 51 #define KEY_USR_READ    0x00020000
 52 #define KEY_USR_WRITE   0x00040000
 53 #define KEY_USR_SEARCH  0x00080000
 54 #define KEY_USR_LINK    0x00100000
 55 #define KEY_USR_SETATTR 0x00200000
 56 #define KEY_USR_ALL     0x003f0000
 57 
 58 #define KEY_GRP_VIEW    0x00000100      /* group permissions... */
 59 #define KEY_GRP_READ    0x00000200
 60 #define KEY_GRP_WRITE   0x00000400
 61 #define KEY_GRP_SEARCH  0x00000800
 62 #define KEY_GRP_LINK    0x00001000
 63 #define KEY_GRP_SETATTR 0x00002000
 64 #define KEY_GRP_ALL     0x00003f00
 65 
 66 #define KEY_OTH_VIEW    0x00000001      /* third party permissions... */
 67 #define KEY_OTH_READ    0x00000002
 68 #define KEY_OTH_WRITE   0x00000004
 69 #define KEY_OTH_SEARCH  0x00000008
 70 #define KEY_OTH_LINK    0x00000010
 71 #define KEY_OTH_SETATTR 0x00000020
 72 #define KEY_OTH_ALL     0x0000003f
 73 
 74 #define KEY_PERM_UNDEF  0xffffffff
 75 
 76 struct seq_file;
 77 struct user_struct;
 78 struct signal_struct;
 79 struct cred;
 80 
 81 struct key_type;
 82 struct key_owner;
 83 struct keyring_list;
 84 struct keyring_name;
 85 
 86 struct keyring_index_key {
 87         struct key_type         *type;
 88         const char              *description;
 89         size_t                  desc_len;
 90 };
 91 
 92 /*****************************************************************************/
 93 /*
 94  * key reference with possession attribute handling
 95  *
 96  * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
 97  * defined. This is because we abuse the bottom bit of the reference to carry a
 98  * flag to indicate whether the calling process possesses that key in one of
 99  * its keyrings.
100  *
101  * the key_ref_t has been made a separate type so that the compiler can reject
102  * attempts to dereference it without proper conversion.
103  *
104  * the three functions are used to assemble and disassemble references
105  */
106 typedef struct __key_reference_with_attributes *key_ref_t;
107 
108 static inline key_ref_t make_key_ref(const struct key *key,
109                                      bool possession)
110 {
111         return (key_ref_t) ((unsigned long) key | possession);
112 }
113 
114 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
115 {
116         return (struct key *) ((unsigned long) key_ref & ~1UL);
117 }
118 
119 static inline bool is_key_possessed(const key_ref_t key_ref)
120 {
121         return (unsigned long) key_ref & 1UL;
122 }
123 
124 /*****************************************************************************/
125 /*
126  * authentication token / access credential / keyring
127  * - types of key include:
128  *   - keyrings
129  *   - disk encryption IDs
130  *   - Kerberos TGTs and tickets
131  */
132 struct key {
133         atomic_t                usage;          /* number of references */
134         key_serial_t            serial;         /* key serial number */
135         union {
136                 struct list_head graveyard_link;
137                 struct rb_node  serial_node;
138         };
139         struct rw_semaphore     sem;            /* change vs change sem */
140         struct key_user         *user;          /* owner of this key */
141         void                    *security;      /* security data for this key */
142         union {
143                 time_t          expiry;         /* time at which key expires (or 0) */
144                 time_t          revoked_at;     /* time at which key was revoked */
145         };
146         time_t                  last_used_at;   /* last time used for LRU keyring discard */
147         kuid_t                  uid;
148         kgid_t                  gid;
149         key_perm_t              perm;           /* access permissions */
150         unsigned short          quotalen;       /* length added to quota */
151         unsigned short          datalen;        /* payload data length
152                                                  * - may not match RCU dereferenced payload
153                                                  * - payload should contain own length
154                                                  */
155 
156 #ifdef KEY_DEBUGGING
157         unsigned                magic;
158 #define KEY_DEBUG_MAGIC         0x18273645u
159 #define KEY_DEBUG_MAGIC_X       0xf8e9dacbu
160 #endif
161 
162         unsigned long           flags;          /* status flags (change with bitops) */
163 #define KEY_FLAG_INSTANTIATED   0       /* set if key has been instantiated */
164 #define KEY_FLAG_DEAD           1       /* set if key type has been deleted */
165 #define KEY_FLAG_REVOKED        2       /* set if key had been revoked */
166 #define KEY_FLAG_IN_QUOTA       3       /* set if key consumes quota */
167 #define KEY_FLAG_USER_CONSTRUCT 4       /* set if key is being constructed in userspace */
168 #define KEY_FLAG_NEGATIVE       5       /* set if key is negative */
169 #define KEY_FLAG_ROOT_CAN_CLEAR 6       /* set if key can be cleared by root without permission */
170 #define KEY_FLAG_INVALIDATED    7       /* set if key has been invalidated */
171 #define KEY_FLAG_TRUSTED        8       /* set if key is trusted */
172 #define KEY_FLAG_TRUSTED_ONLY   9       /* set if keyring only accepts links to trusted keys */
173 #define KEY_FLAG_BUILTIN        10      /* set if key is builtin */
174 #define KEY_FLAG_ROOT_CAN_INVAL 11      /* set if key can be invalidated by root without permission */
175 
176         /* the key type and key description string
177          * - the desc is used to match a key against search criteria
178          * - it should be a printable string
179          * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
180          */
181         union {
182                 struct keyring_index_key index_key;
183                 struct {
184                         struct key_type *type;          /* type of key */
185                         char            *description;
186                 };
187         };
188 
189         /* type specific data
190          * - this is used by the keyring type to index the name
191          */
192         union {
193                 struct list_head        link;
194                 unsigned long           x[2];
195                 void                    *p[2];
196                 int                     reject_error;
197         } type_data;
198 
199         /* key data
200          * - this is used to hold the data actually used in cryptography or
201          *   whatever
202          */
203         union {
204                 union {
205                         unsigned long           value;
206                         void __rcu              *rcudata;
207                         void                    *data;
208                         void                    *data2[2];
209                 } payload;
210                 struct assoc_array keys;
211         };
212 };
213 
214 extern struct key *key_alloc(struct key_type *type,
215                              const char *desc,
216                              kuid_t uid, kgid_t gid,
217                              const struct cred *cred,
218                              key_perm_t perm,
219                              unsigned long flags);
220 
221 
222 #define KEY_ALLOC_IN_QUOTA      0x0000  /* add to quota, reject if would overrun */
223 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001  /* add to quota, permit even if overrun */
224 #define KEY_ALLOC_NOT_IN_QUOTA  0x0002  /* not in quota */
225 #define KEY_ALLOC_TRUSTED       0x0004  /* Key should be flagged as trusted */
226 
227 extern void key_revoke(struct key *key);
228 extern void key_invalidate(struct key *key);
229 extern void key_put(struct key *key);
230 
231 static inline struct key *__key_get(struct key *key)
232 {
233         atomic_inc(&key->usage);
234         return key;
235 }
236 
237 static inline struct key *key_get(struct key *key)
238 {
239         return key ? __key_get(key) : key;
240 }
241 
242 static inline void key_ref_put(key_ref_t key_ref)
243 {
244         key_put(key_ref_to_ptr(key_ref));
245 }
246 
247 extern struct key *request_key(struct key_type *type,
248                                const char *description,
249                                const char *callout_info);
250 
251 extern struct key *request_key_with_auxdata(struct key_type *type,
252                                             const char *description,
253                                             const void *callout_info,
254                                             size_t callout_len,
255                                             void *aux);
256 
257 extern struct key *request_key_async(struct key_type *type,
258                                      const char *description,
259                                      const void *callout_info,
260                                      size_t callout_len);
261 
262 extern struct key *request_key_async_with_auxdata(struct key_type *type,
263                                                   const char *description,
264                                                   const void *callout_info,
265                                                   size_t callout_len,
266                                                   void *aux);
267 
268 extern int wait_for_key_construction(struct key *key, bool intr);
269 
270 extern int key_validate(const struct key *key);
271 
272 extern key_ref_t key_create_or_update(key_ref_t keyring,
273                                       const char *type,
274                                       const char *description,
275                                       const void *payload,
276                                       size_t plen,
277                                       key_perm_t perm,
278                                       unsigned long flags);
279 
280 extern int key_update(key_ref_t key,
281                       const void *payload,
282                       size_t plen);
283 
284 extern int key_link(struct key *keyring,
285                     struct key *key);
286 
287 extern int key_unlink(struct key *keyring,
288                       struct key *key);
289 
290 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
291                                  const struct cred *cred,
292                                  key_perm_t perm,
293                                  unsigned long flags,
294                                  struct key *dest);
295 
296 extern int keyring_clear(struct key *keyring);
297 
298 extern key_ref_t keyring_search(key_ref_t keyring,
299                                 struct key_type *type,
300                                 const char *description);
301 
302 extern int keyring_add_key(struct key *keyring,
303                            struct key *key);
304 
305 extern struct key *key_lookup(key_serial_t id);
306 
307 static inline key_serial_t key_serial(const struct key *key)
308 {
309         return key ? key->serial : 0;
310 }
311 
312 extern void key_set_timeout(struct key *, unsigned);
313 
314 /*
315  * The permissions required on a key that we're looking up.
316  */
317 #define KEY_NEED_VIEW   0x01    /* Require permission to view attributes */
318 #define KEY_NEED_READ   0x02    /* Require permission to read content */
319 #define KEY_NEED_WRITE  0x04    /* Require permission to update / modify */
320 #define KEY_NEED_SEARCH 0x08    /* Require permission to search (keyring) or find (key) */
321 #define KEY_NEED_LINK   0x10    /* Require permission to link */
322 #define KEY_NEED_SETATTR 0x20   /* Require permission to change attributes */
323 #define KEY_NEED_ALL    0x3f    /* All the above permissions */
324 
325 /**
326  * key_is_instantiated - Determine if a key has been positively instantiated
327  * @key: The key to check.
328  *
329  * Return true if the specified key has been positively instantiated, false
330  * otherwise.
331  */
332 static inline bool key_is_instantiated(const struct key *key)
333 {
334         return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
335                 !test_bit(KEY_FLAG_NEGATIVE, &key->flags);
336 }
337 
338 #define rcu_dereference_key(KEY)                                        \
339         (rcu_dereference_protected((KEY)->payload.rcudata,              \
340                                    rwsem_is_locked(&((struct key *)(KEY))->sem)))
341 
342 #define rcu_assign_keypointer(KEY, PAYLOAD)                             \
343 do {                                                                    \
344         rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD));          \
345 } while (0)
346 
347 #ifdef CONFIG_SYSCTL
348 extern struct ctl_table key_sysctls[];
349 #endif
350 /*
351  * the userspace interface
352  */
353 extern int install_thread_keyring_to_cred(struct cred *cred);
354 extern void key_fsuid_changed(struct task_struct *tsk);
355 extern void key_fsgid_changed(struct task_struct *tsk);
356 extern void key_init(void);
357 
358 #else /* CONFIG_KEYS */
359 
360 #define key_validate(k)                 0
361 #define key_serial(k)                   0
362 #define key_get(k)                      ({ NULL; })
363 #define key_revoke(k)                   do { } while(0)
364 #define key_invalidate(k)               do { } while(0)
365 #define key_put(k)                      do { } while(0)
366 #define key_ref_put(k)                  do { } while(0)
367 #define make_key_ref(k, p)              NULL
368 #define key_ref_to_ptr(k)               NULL
369 #define is_key_possessed(k)             0
370 #define key_fsuid_changed(t)            do { } while(0)
371 #define key_fsgid_changed(t)            do { } while(0)
372 #define key_init()                      do { } while(0)
373 
374 #endif /* CONFIG_KEYS */
375 #endif /* __KERNEL__ */
376 #endif /* _LINUX_KEY_H */
377 

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