1 /* Authentication token and access key management 2 * 3 * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells ([email protected]) 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 */ 173 174 /* the key type and key description string 175 * - the desc is used to match a key against search criteria 176 * - it should be a printable string 177 * - eg: for krb5 AFS, this might be "[email protected]" 178 */ 179 union { 180 struct keyring_index_key index_key; 181 struct { 182 struct key_type *type; /* type of key */ 183 char *description; 184 }; 185 }; 186 187 /* type specific data 188 * - this is used by the keyring type to index the name 189 */ 190 union { 191 struct list_head link; 192 unsigned long x[2]; 193 void *p[2]; 194 int reject_error; 195 } type_data; 196 197 /* key data 198 * - this is used to hold the data actually used in cryptography or 199 * whatever 200 */ 201 union { 202 union { 203 unsigned long value; 204 void __rcu *rcudata; 205 void *data; 206 void *data2[2]; 207 } payload; 208 struct assoc_array keys; 209 }; 210 }; 211 212 extern struct key *key_alloc(struct key_type *type, 213 const char *desc, 214 kuid_t uid, kgid_t gid, 215 const struct cred *cred, 216 key_perm_t perm, 217 unsigned long flags); 218 219 220 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 221 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 222 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 223 #define KEY_ALLOC_TRUSTED 0x0004 /* Key should be flagged as trusted */ 224 225 extern void key_revoke(struct key *key); 226 extern void key_invalidate(struct key *key); 227 extern void key_put(struct key *key); 228 229 static inline struct key *__key_get(struct key *key) 230 { 231 atomic_inc(&key->usage); 232 return key; 233 } 234 235 static inline struct key *key_get(struct key *key) 236 { 237 return key ? __key_get(key) : key; 238 } 239 240 static inline void key_ref_put(key_ref_t key_ref) 241 { 242 key_put(key_ref_to_ptr(key_ref)); 243 } 244 245 extern struct key *request_key(struct key_type *type, 246 const char *description, 247 const char *callout_info); 248 249 extern struct key *request_key_with_auxdata(struct key_type *type, 250 const char *description, 251 const void *callout_info, 252 size_t callout_len, 253 void *aux); 254 255 extern struct key *request_key_async(struct key_type *type, 256 const char *description, 257 const void *callout_info, 258 size_t callout_len); 259 260 extern struct key *request_key_async_with_auxdata(struct key_type *type, 261 const char *description, 262 const void *callout_info, 263 size_t callout_len, 264 void *aux); 265 266 extern int wait_for_key_construction(struct key *key, bool intr); 267 268 extern int key_validate(const struct key *key); 269 270 extern key_ref_t key_create_or_update(key_ref_t keyring, 271 const char *type, 272 const char *description, 273 const void *payload, 274 size_t plen, 275 key_perm_t perm, 276 unsigned long flags); 277 278 extern int key_update(key_ref_t key, 279 const void *payload, 280 size_t plen); 281 282 extern int key_link(struct key *keyring, 283 struct key *key); 284 285 extern int key_unlink(struct key *keyring, 286 struct key *key); 287 288 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, 289 const struct cred *cred, 290 key_perm_t perm, 291 unsigned long flags, 292 struct key *dest); 293 294 extern int keyring_clear(struct key *keyring); 295 296 extern key_ref_t keyring_search(key_ref_t keyring, 297 struct key_type *type, 298 const char *description); 299 300 extern int keyring_add_key(struct key *keyring, 301 struct key *key); 302 303 extern struct key *key_lookup(key_serial_t id); 304 305 static inline key_serial_t key_serial(const struct key *key) 306 { 307 return key ? key->serial : 0; 308 } 309 310 extern void key_set_timeout(struct key *, unsigned); 311 312 /** 313 * key_is_instantiated - Determine if a key has been positively instantiated 314 * @key: The key to check. 315 * 316 * Return true if the specified key has been positively instantiated, false 317 * otherwise. 318 */ 319 static inline bool key_is_instantiated(const struct key *key) 320 { 321 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && 322 !test_bit(KEY_FLAG_NEGATIVE, &key->flags); 323 } 324 325 #define rcu_dereference_key(KEY) \ 326 (rcu_dereference_protected((KEY)->payload.rcudata, \ 327 rwsem_is_locked(&((struct key *)(KEY))->sem))) 328 329 #define rcu_assign_keypointer(KEY, PAYLOAD) \ 330 do { \ 331 rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \ 332 } while (0) 333 334 #ifdef CONFIG_SYSCTL 335 extern ctl_table key_sysctls[]; 336 #endif 337 /* 338 * the userspace interface 339 */ 340 extern int install_thread_keyring_to_cred(struct cred *cred); 341 extern void key_fsuid_changed(struct task_struct *tsk); 342 extern void key_fsgid_changed(struct task_struct *tsk); 343 extern void key_init(void); 344 345 #else /* CONFIG_KEYS */ 346 347 #define key_validate(k) 0 348 #define key_serial(k) 0 349 #define key_get(k) ({ NULL; }) 350 #define key_revoke(k) do { } while(0) 351 #define key_invalidate(k) do { } while(0) 352 #define key_put(k) do { } while(0) 353 #define key_ref_put(k) do { } while(0) 354 #define make_key_ref(k, p) NULL 355 #define key_ref_to_ptr(k) NULL 356 #define is_key_possessed(k) 0 357 #define key_fsuid_changed(t) do { } while(0) 358 #define key_fsgid_changed(t) do { } while(0) 359 #define key_init() do { } while(0) 360 361 #endif /* CONFIG_KEYS */ 362 #endif /* __KERNEL__ */ 363 #endif /* _LINUX_KEY_H */ 364