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 union key_payload { 93 void __rcu *rcu_data0; 94 void *data[4]; 95 }; 96 97 /*****************************************************************************/ 98 /* 99 * key reference with possession attribute handling 100 * 101 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 102 * defined. This is because we abuse the bottom bit of the reference to carry a 103 * flag to indicate whether the calling process possesses that key in one of 104 * its keyrings. 105 * 106 * the key_ref_t has been made a separate type so that the compiler can reject 107 * attempts to dereference it without proper conversion. 108 * 109 * the three functions are used to assemble and disassemble references 110 */ 111 typedef struct __key_reference_with_attributes *key_ref_t; 112 113 static inline key_ref_t make_key_ref(const struct key *key, 114 bool possession) 115 { 116 return (key_ref_t) ((unsigned long) key | possession); 117 } 118 119 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 120 { 121 return (struct key *) ((unsigned long) key_ref & ~1UL); 122 } 123 124 static inline bool is_key_possessed(const key_ref_t key_ref) 125 { 126 return (unsigned long) key_ref & 1UL; 127 } 128 129 /*****************************************************************************/ 130 /* 131 * authentication token / access credential / keyring 132 * - types of key include: 133 * - keyrings 134 * - disk encryption IDs 135 * - Kerberos TGTs and tickets 136 */ 137 struct key { 138 atomic_t usage; /* number of references */ 139 key_serial_t serial; /* key serial number */ 140 union { 141 struct list_head graveyard_link; 142 struct rb_node serial_node; 143 }; 144 struct rw_semaphore sem; /* change vs change sem */ 145 struct key_user *user; /* owner of this key */ 146 void *security; /* security data for this key */ 147 union { 148 time_t expiry; /* time at which key expires (or 0) */ 149 time_t revoked_at; /* time at which key was revoked */ 150 }; 151 time_t last_used_at; /* last time used for LRU keyring discard */ 152 kuid_t uid; 153 kgid_t gid; 154 key_perm_t perm; /* access permissions */ 155 unsigned short quotalen; /* length added to quota */ 156 unsigned short datalen; /* payload data length 157 * - may not match RCU dereferenced payload 158 * - payload should contain own length 159 */ 160 161 #ifdef KEY_DEBUGGING 162 unsigned magic; 163 #define KEY_DEBUG_MAGIC 0x18273645u 164 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 165 #endif 166 167 unsigned long flags; /* status flags (change with bitops) */ 168 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 169 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 170 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 171 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 172 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 173 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 174 #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ 175 #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ 176 #define KEY_FLAG_BUILTIN 8 /* set if key is built in to the kernel */ 177 #define KEY_FLAG_ROOT_CAN_INVAL 9 /* set if key can be invalidated by root without permission */ 178 #define KEY_FLAG_KEEP 10 /* set if key should not be removed */ 179 180 /* the key type and key description string 181 * - the desc is used to match a key against search criteria 182 * - it should be a printable string 183 * - eg: for krb5 AFS, this might be "[email protected]" 184 */ 185 union { 186 struct keyring_index_key index_key; 187 struct { 188 struct key_type *type; /* type of key */ 189 char *description; 190 }; 191 }; 192 193 /* key data 194 * - this is used to hold the data actually used in cryptography or 195 * whatever 196 */ 197 union { 198 union key_payload payload; 199 struct { 200 /* Keyring bits */ 201 struct list_head name_link; 202 struct assoc_array keys; 203 }; 204 int reject_error; 205 }; 206 207 /* This is set on a keyring to restrict the addition of a link to a key 208 * to it. If this method isn't provided then it is assumed that the 209 * keyring is open to any addition. It is ignored for non-keyring 210 * keys. 211 * 212 * This is intended for use with rings of trusted keys whereby addition 213 * to the keyring needs to be controlled. KEY_ALLOC_BYPASS_RESTRICTION 214 * overrides this, allowing the kernel to add extra keys without 215 * restriction. 216 */ 217 int (*restrict_link)(struct key *keyring, 218 const struct key_type *type, 219 const union key_payload *payload); 220 }; 221 222 extern struct key *key_alloc(struct key_type *type, 223 const char *desc, 224 kuid_t uid, kgid_t gid, 225 const struct cred *cred, 226 key_perm_t perm, 227 unsigned long flags, 228 int (*restrict_link)(struct key *, 229 const struct key_type *, 230 const union key_payload *)); 231 232 233 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 234 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 235 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 236 #define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */ 237 #define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */ 238 239 extern void key_revoke(struct key *key); 240 extern void key_invalidate(struct key *key); 241 extern void key_put(struct key *key); 242 243 static inline struct key *__key_get(struct key *key) 244 { 245 atomic_inc(&key->usage); 246 return key; 247 } 248 249 static inline struct key *key_get(struct key *key) 250 { 251 return key ? __key_get(key) : key; 252 } 253 254 static inline void key_ref_put(key_ref_t key_ref) 255 { 256 key_put(key_ref_to_ptr(key_ref)); 257 } 258 259 extern struct key *request_key(struct key_type *type, 260 const char *description, 261 const char *callout_info); 262 263 extern struct key *request_key_with_auxdata(struct key_type *type, 264 const char *description, 265 const void *callout_info, 266 size_t callout_len, 267 void *aux); 268 269 extern struct key *request_key_async(struct key_type *type, 270 const char *description, 271 const void *callout_info, 272 size_t callout_len); 273 274 extern struct key *request_key_async_with_auxdata(struct key_type *type, 275 const char *description, 276 const void *callout_info, 277 size_t callout_len, 278 void *aux); 279 280 extern int wait_for_key_construction(struct key *key, bool intr); 281 282 extern int key_validate(const struct key *key); 283 284 extern key_ref_t key_create_or_update(key_ref_t keyring, 285 const char *type, 286 const char *description, 287 const void *payload, 288 size_t plen, 289 key_perm_t perm, 290 unsigned long flags); 291 292 extern int key_update(key_ref_t key, 293 const void *payload, 294 size_t plen); 295 296 extern int key_link(struct key *keyring, 297 struct key *key); 298 299 extern int key_unlink(struct key *keyring, 300 struct key *key); 301 302 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, 303 const struct cred *cred, 304 key_perm_t perm, 305 unsigned long flags, 306 int (*restrict_link)(struct key *, 307 const struct key_type *, 308 const union key_payload *), 309 struct key *dest); 310 311 extern int restrict_link_reject(struct key *keyring, 312 const struct key_type *type, 313 const union key_payload *payload); 314 315 extern int keyring_clear(struct key *keyring); 316 317 extern key_ref_t keyring_search(key_ref_t keyring, 318 struct key_type *type, 319 const char *description); 320 321 extern int keyring_add_key(struct key *keyring, 322 struct key *key); 323 324 extern struct key *key_lookup(key_serial_t id); 325 326 static inline key_serial_t key_serial(const struct key *key) 327 { 328 return key ? key->serial : 0; 329 } 330 331 extern void key_set_timeout(struct key *, unsigned); 332 333 /* 334 * The permissions required on a key that we're looking up. 335 */ 336 #define KEY_NEED_VIEW 0x01 /* Require permission to view attributes */ 337 #define KEY_NEED_READ 0x02 /* Require permission to read content */ 338 #define KEY_NEED_WRITE 0x04 /* Require permission to update / modify */ 339 #define KEY_NEED_SEARCH 0x08 /* Require permission to search (keyring) or find (key) */ 340 #define KEY_NEED_LINK 0x10 /* Require permission to link */ 341 #define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */ 342 #define KEY_NEED_ALL 0x3f /* All the above permissions */ 343 344 /** 345 * key_is_instantiated - Determine if a key has been positively instantiated 346 * @key: The key to check. 347 * 348 * Return true if the specified key has been positively instantiated, false 349 * otherwise. 350 */ 351 static inline bool key_is_instantiated(const struct key *key) 352 { 353 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && 354 !test_bit(KEY_FLAG_NEGATIVE, &key->flags); 355 } 356 357 #define rcu_dereference_key(KEY) \ 358 (rcu_dereference_protected((KEY)->payload.rcu_data0, \ 359 rwsem_is_locked(&((struct key *)(KEY))->sem))) 360 361 #define rcu_assign_keypointer(KEY, PAYLOAD) \ 362 do { \ 363 rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \ 364 } while (0) 365 366 #ifdef CONFIG_SYSCTL 367 extern struct ctl_table key_sysctls[]; 368 #endif 369 /* 370 * the userspace interface 371 */ 372 extern int install_thread_keyring_to_cred(struct cred *cred); 373 extern void key_fsuid_changed(struct task_struct *tsk); 374 extern void key_fsgid_changed(struct task_struct *tsk); 375 extern void key_init(void); 376 377 #else /* CONFIG_KEYS */ 378 379 #define key_validate(k) 0 380 #define key_serial(k) 0 381 #define key_get(k) ({ NULL; }) 382 #define key_revoke(k) do { } while(0) 383 #define key_invalidate(k) do { } while(0) 384 #define key_put(k) do { } while(0) 385 #define key_ref_put(k) do { } while(0) 386 #define make_key_ref(k, p) NULL 387 #define key_ref_to_ptr(k) NULL 388 #define is_key_possessed(k) 0 389 #define key_fsuid_changed(t) do { } while(0) 390 #define key_fsgid_changed(t) do { } while(0) 391 #define key_init() do { } while(0) 392 393 #endif /* CONFIG_KEYS */ 394 #endif /* __KERNEL__ */ 395 #endif /* _LINUX_KEY_H */ 396