1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* Authentication token and access key management 3 * 4 * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 * 7 * See Documentation/security/keys/core.rst for information on keys/keyrings. 8 */ 9 10 #ifndef _LINUX_KEY_H 11 #define _LINUX_KEY_H 12 13 #include <linux/types.h> 14 #include <linux/list.h> 15 #include <linux/rbtree.h> 16 #include <linux/rcupdate.h> 17 #include <linux/sysctl.h> 18 #include <linux/rwsem.h> 19 #include <linux/atomic.h> 20 #include <linux/assoc_array.h> 21 #include <linux/refcount.h> 22 #include <linux/time64.h> 23 24 #ifdef __KERNEL__ 25 #include <linux/uidgid.h> 26 27 /* key handle serial number */ 28 typedef int32_t key_serial_t; 29 30 /* key handle permissions mask */ 31 typedef uint32_t key_perm_t; 32 33 struct key; 34 struct net; 35 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 key_tag; 82 struct keyring_list; 83 struct keyring_name; 84 85 struct key_tag { 86 struct rcu_head rcu; 87 refcount_t usage; 88 bool removed; /* T when subject removed */ 89 }; 90 91 struct keyring_index_key { 92 /* [!] If this structure is altered, the union in struct key must change too! */ 93 unsigned long hash; /* Hash value */ 94 union { 95 struct { 96 #ifdef __LITTLE_ENDIAN /* Put desc_len at the LSB of x */ 97 u16 desc_len; 98 char desc[sizeof(long) - 2]; /* First few chars of description */ 99 #else 100 char desc[sizeof(long) - 2]; /* First few chars of description */ 101 u16 desc_len; 102 #endif 103 }; 104 unsigned long x; 105 }; 106 struct key_type *type; 107 struct key_tag *domain_tag; /* Domain of operation */ 108 const char *description; 109 }; 110 111 union key_payload { 112 void __rcu *rcu_data0; 113 void *data[4]; 114 }; 115 116 /*****************************************************************************/ 117 /* 118 * key reference with possession attribute handling 119 * 120 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 121 * defined. This is because we abuse the bottom bit of the reference to carry a 122 * flag to indicate whether the calling process possesses that key in one of 123 * its keyrings. 124 * 125 * the key_ref_t has been made a separate type so that the compiler can reject 126 * attempts to dereference it without proper conversion. 127 * 128 * the three functions are used to assemble and disassemble references 129 */ 130 typedef struct __key_reference_with_attributes *key_ref_t; 131 132 static inline key_ref_t make_key_ref(const struct key *key, 133 bool possession) 134 { 135 return (key_ref_t) ((unsigned long) key | possession); 136 } 137 138 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 139 { 140 return (struct key *) ((unsigned long) key_ref & ~1UL); 141 } 142 143 static inline bool is_key_possessed(const key_ref_t key_ref) 144 { 145 return (unsigned long) key_ref & 1UL; 146 } 147 148 typedef int (*key_restrict_link_func_t)(struct key *dest_keyring, 149 const struct key_type *type, 150 const union key_payload *payload, 151 struct key *restriction_key); 152 153 struct key_restriction { 154 key_restrict_link_func_t check; 155 struct key *key; 156 struct key_type *keytype; 157 }; 158 159 enum key_state { 160 KEY_IS_UNINSTANTIATED, 161 KEY_IS_POSITIVE, /* Positively instantiated */ 162 }; 163 164 /*****************************************************************************/ 165 /* 166 * authentication token / access credential / keyring 167 * - types of key include: 168 * - keyrings 169 * - disk encryption IDs 170 * - Kerberos TGTs and tickets 171 */ 172 struct key { 173 refcount_t usage; /* number of references */ 174 key_serial_t serial; /* key serial number */ 175 union { 176 struct list_head graveyard_link; 177 struct rb_node serial_node; 178 }; 179 struct rw_semaphore sem; /* change vs change sem */ 180 struct key_user *user; /* owner of this key */ 181 void *security; /* security data for this key */ 182 union { 183 time64_t expiry; /* time at which key expires (or 0) */ 184 time64_t revoked_at; /* time at which key was revoked */ 185 }; 186 time64_t last_used_at; /* last time used for LRU keyring discard */ 187 kuid_t uid; 188 kgid_t gid; 189 key_perm_t perm; /* access permissions */ 190 unsigned short quotalen; /* length added to quota */ 191 unsigned short datalen; /* payload data length 192 * - may not match RCU dereferenced payload 193 * - payload should contain own length 194 */ 195 short state; /* Key state (+) or rejection error (-) */ 196 197 #ifdef KEY_DEBUGGING 198 unsigned magic; 199 #define KEY_DEBUG_MAGIC 0x18273645u 200 #endif 201 202 unsigned long flags; /* status flags (change with bitops) */ 203 #define KEY_FLAG_DEAD 0 /* set if key type has been deleted */ 204 #define KEY_FLAG_REVOKED 1 /* set if key had been revoked */ 205 #define KEY_FLAG_IN_QUOTA 2 /* set if key consumes quota */ 206 #define KEY_FLAG_USER_CONSTRUCT 3 /* set if key is being constructed in userspace */ 207 #define KEY_FLAG_ROOT_CAN_CLEAR 4 /* set if key can be cleared by root without permission */ 208 #define KEY_FLAG_INVALIDATED 5 /* set if key has been invalidated */ 209 #define KEY_FLAG_BUILTIN 6 /* set if key is built in to the kernel */ 210 #define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */ 211 #define KEY_FLAG_KEEP 8 /* set if key should not be removed */ 212 #define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */ 213 214 /* the key type and key description string 215 * - the desc is used to match a key against search criteria 216 * - it should be a printable string 217 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" 218 */ 219 union { 220 struct keyring_index_key index_key; 221 struct { 222 unsigned long hash; 223 unsigned long len_desc; 224 struct key_type *type; /* type of key */ 225 struct key_tag *domain_tag; /* Domain of operation */ 226 char *description; 227 }; 228 }; 229 230 /* key data 231 * - this is used to hold the data actually used in cryptography or 232 * whatever 233 */ 234 union { 235 union key_payload payload; 236 struct { 237 /* Keyring bits */ 238 struct list_head name_link; 239 struct assoc_array keys; 240 }; 241 }; 242 243 /* This is set on a keyring to restrict the addition of a link to a key 244 * to it. If this structure isn't provided then it is assumed that the 245 * keyring is open to any addition. It is ignored for non-keyring 246 * keys. Only set this value using keyring_restrict(), keyring_alloc(), 247 * or key_alloc(). 248 * 249 * This is intended for use with rings of trusted keys whereby addition 250 * to the keyring needs to be controlled. KEY_ALLOC_BYPASS_RESTRICTION 251 * overrides this, allowing the kernel to add extra keys without 252 * restriction. 253 */ 254 struct key_restriction *restrict_link; 255 }; 256 257 extern struct key *key_alloc(struct key_type *type, 258 const char *desc, 259 kuid_t uid, kgid_t gid, 260 const struct cred *cred, 261 key_perm_t perm, 262 unsigned long flags, 263 struct key_restriction *restrict_link); 264 265 266 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 267 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 268 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 269 #define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */ 270 #define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */ 271 #define KEY_ALLOC_UID_KEYRING 0x0010 /* allocating a user or user session keyring */ 272 273 extern void key_revoke(struct key *key); 274 extern void key_invalidate(struct key *key); 275 extern void key_put(struct key *key); 276 extern bool key_put_tag(struct key_tag *tag); 277 extern void key_remove_domain(struct key_tag *domain_tag); 278 279 static inline struct key *__key_get(struct key *key) 280 { 281 refcount_inc(&key->usage); 282 return key; 283 } 284 285 static inline struct key *key_get(struct key *key) 286 { 287 return key ? __key_get(key) : key; 288 } 289 290 static inline void key_ref_put(key_ref_t key_ref) 291 { 292 key_put(key_ref_to_ptr(key_ref)); 293 } 294 295 extern struct key *request_key_tag(struct key_type *type, 296 const char *description, 297 struct key_tag *domain_tag, 298 const char *callout_info); 299 300 extern struct key *request_key_rcu(struct key_type *type, 301 const char *description, 302 struct key_tag *domain_tag); 303 304 extern struct key *request_key_with_auxdata(struct key_type *type, 305 const char *description, 306 struct key_tag *domain_tag, 307 const void *callout_info, 308 size_t callout_len, 309 void *aux); 310 311 /** 312 * request_key - Request a key and wait for construction 313 * @type: Type of key. 314 * @description: The searchable description of the key. 315 * @callout_info: The data to pass to the instantiation upcall (or NULL). 316 * 317 * As for request_key_tag(), but with the default global domain tag. 318 */ 319 static inline struct key *request_key(struct key_type *type, 320 const char *description, 321 const char *callout_info) 322 { 323 return request_key_tag(type, description, NULL, callout_info); 324 } 325 326 #ifdef CONFIG_NET 327 /** 328 * request_key_net - Request a key for a net namespace and wait for construction 329 * @type: Type of key. 330 * @description: The searchable description of the key. 331 * @net: The network namespace that is the key's domain of operation. 332 * @callout_info: The data to pass to the instantiation upcall (or NULL). 333 * 334 * As for request_key() except that it does not add the returned key to a 335 * keyring if found, new keys are always allocated in the user's quota, the 336 * callout_info must be a NUL-terminated string and no auxiliary data can be 337 * passed. Only keys that operate the specified network namespace are used. 338 * 339 * Furthermore, it then works as wait_for_key_construction() to wait for the 340 * completion of keys undergoing construction with a non-interruptible wait. 341 */ 342 #define request_key_net(type, description, net, callout_info) \ 343 request_key_tag(type, description, net->key_domain, callout_info); 344 345 /** 346 * request_key_net_rcu - Request a key for a net namespace under RCU conditions 347 * @type: Type of key. 348 * @description: The searchable description of the key. 349 * @net: The network namespace that is the key's domain of operation. 350 * 351 * As for request_key_rcu() except that only keys that operate the specified 352 * network namespace are used. 353 */ 354 #define request_key_net_rcu(type, description, net) \ 355 request_key_rcu(type, description, net->key_domain); 356 #endif /* CONFIG_NET */ 357 358 extern int wait_for_key_construction(struct key *key, bool intr); 359 360 extern int key_validate(const struct key *key); 361 362 extern key_ref_t key_create_or_update(key_ref_t keyring, 363 const char *type, 364 const char *description, 365 const void *payload, 366 size_t plen, 367 key_perm_t perm, 368 unsigned long flags); 369 370 extern int key_update(key_ref_t key, 371 const void *payload, 372 size_t plen); 373 374 extern int key_link(struct key *keyring, 375 struct key *key); 376 377 extern int key_move(struct key *key, 378 struct key *from_keyring, 379 struct key *to_keyring, 380 unsigned int flags); 381 382 extern int key_unlink(struct key *keyring, 383 struct key *key); 384 385 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, 386 const struct cred *cred, 387 key_perm_t perm, 388 unsigned long flags, 389 struct key_restriction *restrict_link, 390 struct key *dest); 391 392 extern int restrict_link_reject(struct key *keyring, 393 const struct key_type *type, 394 const union key_payload *payload, 395 struct key *restriction_key); 396 397 extern int keyring_clear(struct key *keyring); 398 399 extern key_ref_t keyring_search(key_ref_t keyring, 400 struct key_type *type, 401 const char *description, 402 bool recurse); 403 404 extern int keyring_add_key(struct key *keyring, 405 struct key *key); 406 407 extern int keyring_restrict(key_ref_t keyring, const char *type, 408 const char *restriction); 409 410 extern struct key *key_lookup(key_serial_t id); 411 412 static inline key_serial_t key_serial(const struct key *key) 413 { 414 return key ? key->serial : 0; 415 } 416 417 extern void key_set_timeout(struct key *, unsigned); 418 419 extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags, 420 key_perm_t perm); 421 extern void key_free_user_ns(struct user_namespace *); 422 423 /* 424 * The permissions required on a key that we're looking up. 425 */ 426 #define KEY_NEED_VIEW 0x01 /* Require permission to view attributes */ 427 #define KEY_NEED_READ 0x02 /* Require permission to read content */ 428 #define KEY_NEED_WRITE 0x04 /* Require permission to update / modify */ 429 #define KEY_NEED_SEARCH 0x08 /* Require permission to search (keyring) or find (key) */ 430 #define KEY_NEED_LINK 0x10 /* Require permission to link */ 431 #define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */ 432 #define KEY_NEED_ALL 0x3f /* All the above permissions */ 433 434 static inline short key_read_state(const struct key *key) 435 { 436 /* Barrier versus mark_key_instantiated(). */ 437 return smp_load_acquire(&key->state); 438 } 439 440 /** 441 * key_is_positive - Determine if a key has been positively instantiated 442 * @key: The key to check. 443 * 444 * Return true if the specified key has been positively instantiated, false 445 * otherwise. 446 */ 447 static inline bool key_is_positive(const struct key *key) 448 { 449 return key_read_state(key) == KEY_IS_POSITIVE; 450 } 451 452 static inline bool key_is_negative(const struct key *key) 453 { 454 return key_read_state(key) < 0; 455 } 456 457 #define dereference_key_rcu(KEY) \ 458 (rcu_dereference((KEY)->payload.rcu_data0)) 459 460 #define dereference_key_locked(KEY) \ 461 (rcu_dereference_protected((KEY)->payload.rcu_data0, \ 462 rwsem_is_locked(&((struct key *)(KEY))->sem))) 463 464 #define rcu_assign_keypointer(KEY, PAYLOAD) \ 465 do { \ 466 rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \ 467 } while (0) 468 469 #ifdef CONFIG_SYSCTL 470 extern struct ctl_table key_sysctls[]; 471 #endif 472 /* 473 * the userspace interface 474 */ 475 extern int install_thread_keyring_to_cred(struct cred *cred); 476 extern void key_fsuid_changed(struct cred *new_cred); 477 extern void key_fsgid_changed(struct cred *new_cred); 478 extern void key_init(void); 479 480 #else /* CONFIG_KEYS */ 481 482 #define key_validate(k) 0 483 #define key_serial(k) 0 484 #define key_get(k) ({ NULL; }) 485 #define key_revoke(k) do { } while(0) 486 #define key_invalidate(k) do { } while(0) 487 #define key_put(k) do { } while(0) 488 #define key_ref_put(k) do { } while(0) 489 #define make_key_ref(k, p) NULL 490 #define key_ref_to_ptr(k) NULL 491 #define is_key_possessed(k) 0 492 #define key_fsuid_changed(c) do { } while(0) 493 #define key_fsgid_changed(c) do { } while(0) 494 #define key_init() do { } while(0) 495 #define key_free_user_ns(ns) do { } while(0) 496 #define key_remove_domain(d) do { } while(0) 497 498 #endif /* CONFIG_KEYS */ 499 #endif /* __KERNEL__ */ 500 #endif /* _LINUX_KEY_H */ 501