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 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_TRUSTED 8 /* set if key is trusted */ 177 #define KEY_FLAG_TRUSTED_ONLY 9 /* set if keyring only accepts links to trusted keys */ 178 #define KEY_FLAG_BUILTIN 10 /* set if key is builtin */ 179 #define KEY_FLAG_ROOT_CAN_INVAL 11 /* set if key can be invalidated by root without permission */ 180 #define KEY_FLAG_KEEP 12 /* set if key should not be removed */ 181 182 /* the key type and key description string 183 * - the desc is used to match a key against search criteria 184 * - it should be a printable string 185 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" 186 */ 187 union { 188 struct keyring_index_key index_key; 189 struct { 190 struct key_type *type; /* type of key */ 191 char *description; 192 }; 193 }; 194 195 /* key data 196 * - this is used to hold the data actually used in cryptography or 197 * whatever 198 */ 199 union { 200 union key_payload payload; 201 struct { 202 /* Keyring bits */ 203 struct list_head name_link; 204 struct assoc_array keys; 205 }; 206 int reject_error; 207 }; 208 }; 209 210 extern struct key *key_alloc(struct key_type *type, 211 const char *desc, 212 kuid_t uid, kgid_t gid, 213 const struct cred *cred, 214 key_perm_t perm, 215 unsigned long flags); 216 217 218 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 219 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 220 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 221 #define KEY_ALLOC_TRUSTED 0x0004 /* Key should be flagged as trusted */ 222 223 extern void key_revoke(struct key *key); 224 extern void key_invalidate(struct key *key); 225 extern void key_put(struct key *key); 226 227 static inline struct key *__key_get(struct key *key) 228 { 229 atomic_inc(&key->usage); 230 return key; 231 } 232 233 static inline struct key *key_get(struct key *key) 234 { 235 return key ? __key_get(key) : key; 236 } 237 238 static inline void key_ref_put(key_ref_t key_ref) 239 { 240 key_put(key_ref_to_ptr(key_ref)); 241 } 242 243 extern struct key *request_key(struct key_type *type, 244 const char *description, 245 const char *callout_info); 246 247 extern struct key *request_key_with_auxdata(struct key_type *type, 248 const char *description, 249 const void *callout_info, 250 size_t callout_len, 251 void *aux); 252 253 extern struct key *request_key_async(struct key_type *type, 254 const char *description, 255 const void *callout_info, 256 size_t callout_len); 257 258 extern struct key *request_key_async_with_auxdata(struct key_type *type, 259 const char *description, 260 const void *callout_info, 261 size_t callout_len, 262 void *aux); 263 264 extern int wait_for_key_construction(struct key *key, bool intr); 265 266 extern int key_validate(const struct key *key); 267 268 extern key_ref_t key_create_or_update(key_ref_t keyring, 269 const char *type, 270 const char *description, 271 const void *payload, 272 size_t plen, 273 key_perm_t perm, 274 unsigned long flags); 275 276 extern int key_update(key_ref_t key, 277 const void *payload, 278 size_t plen); 279 280 extern int key_link(struct key *keyring, 281 struct key *key); 282 283 extern int key_unlink(struct key *keyring, 284 struct key *key); 285 286 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, 287 const struct cred *cred, 288 key_perm_t perm, 289 unsigned long flags, 290 struct key *dest); 291 292 extern int keyring_clear(struct key *keyring); 293 294 extern key_ref_t keyring_search(key_ref_t keyring, 295 struct key_type *type, 296 const char *description); 297 298 extern int keyring_add_key(struct key *keyring, 299 struct key *key); 300 301 extern struct key *key_lookup(key_serial_t id); 302 303 static inline key_serial_t key_serial(const struct key *key) 304 { 305 return key ? key->serial : 0; 306 } 307 308 extern void key_set_timeout(struct key *, unsigned); 309 310 /* 311 * The permissions required on a key that we're looking up. 312 */ 313 #define KEY_NEED_VIEW 0x01 /* Require permission to view attributes */ 314 #define KEY_NEED_READ 0x02 /* Require permission to read content */ 315 #define KEY_NEED_WRITE 0x04 /* Require permission to update / modify */ 316 #define KEY_NEED_SEARCH 0x08 /* Require permission to search (keyring) or find (key) */ 317 #define KEY_NEED_LINK 0x10 /* Require permission to link */ 318 #define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */ 319 #define KEY_NEED_ALL 0x3f /* All the above permissions */ 320 321 /** 322 * key_is_instantiated - Determine if a key has been positively instantiated 323 * @key: The key to check. 324 * 325 * Return true if the specified key has been positively instantiated, false 326 * otherwise. 327 */ 328 static inline bool key_is_instantiated(const struct key *key) 329 { 330 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && 331 !test_bit(KEY_FLAG_NEGATIVE, &key->flags); 332 } 333 334 #define rcu_dereference_key(KEY) \ 335 (rcu_dereference_protected((KEY)->payload.rcu_data0, \ 336 rwsem_is_locked(&((struct key *)(KEY))->sem))) 337 338 #define rcu_assign_keypointer(KEY, PAYLOAD) \ 339 do { \ 340 rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \ 341 } while (0) 342 343 #ifdef CONFIG_SYSCTL 344 extern struct ctl_table key_sysctls[]; 345 #endif 346 /* 347 * the userspace interface 348 */ 349 extern int install_thread_keyring_to_cred(struct cred *cred); 350 extern void key_fsuid_changed(struct task_struct *tsk); 351 extern void key_fsgid_changed(struct task_struct *tsk); 352 extern void key_init(void); 353 354 #else /* CONFIG_KEYS */ 355 356 #define key_validate(k) 0 357 #define key_serial(k) 0 358 #define key_get(k) ({ NULL; }) 359 #define key_revoke(k) do { } while(0) 360 #define key_invalidate(k) do { } while(0) 361 #define key_put(k) do { } while(0) 362 #define key_ref_put(k) do { } while(0) 363 #define make_key_ref(k, p) NULL 364 #define key_ref_to_ptr(k) NULL 365 #define is_key_possessed(k) 0 366 #define key_fsuid_changed(t) do { } while(0) 367 #define key_fsgid_changed(t) do { } while(0) 368 #define key_init() do { } while(0) 369 370 #endif /* CONFIG_KEYS */ 371 #endif /* __KERNEL__ */ 372 #endif /* _LINUX_KEY_H */ 373