1 /* key.h: authentication token and access key management 2 * 3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells (at) 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/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 <asm/atomic.h> 23 24 #ifdef __KERNEL__ 25 26 /* key handle serial number */ 27 typedef int32_t key_serial_t; 28 29 /* key handle permissions mask */ 30 typedef uint32_t key_perm_t; 31 32 struct key; 33 34 #ifdef CONFIG_KEYS 35 36 #undef KEY_DEBUGGING 37 38 #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */ 39 #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */ 40 #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */ 41 #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */ 42 #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */ 43 #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */ 44 #define KEY_POS_ALL 0x3f000000 45 46 #define KEY_USR_VIEW 0x00010000 /* user permissions... */ 47 #define KEY_USR_READ 0x00020000 48 #define KEY_USR_WRITE 0x00040000 49 #define KEY_USR_SEARCH 0x00080000 50 #define KEY_USR_LINK 0x00100000 51 #define KEY_USR_SETATTR 0x00200000 52 #define KEY_USR_ALL 0x003f0000 53 54 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ 55 #define KEY_GRP_READ 0x00000200 56 #define KEY_GRP_WRITE 0x00000400 57 #define KEY_GRP_SEARCH 0x00000800 58 #define KEY_GRP_LINK 0x00001000 59 #define KEY_GRP_SETATTR 0x00002000 60 #define KEY_GRP_ALL 0x00003f00 61 62 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ 63 #define KEY_OTH_READ 0x00000002 64 #define KEY_OTH_WRITE 0x00000004 65 #define KEY_OTH_SEARCH 0x00000008 66 #define KEY_OTH_LINK 0x00000010 67 #define KEY_OTH_SETATTR 0x00000020 68 #define KEY_OTH_ALL 0x0000003f 69 70 struct seq_file; 71 struct user_struct; 72 struct signal_struct; 73 74 struct key_type; 75 struct key_owner; 76 struct keyring_list; 77 struct keyring_name; 78 79 /*****************************************************************************/ 80 /* 81 * key reference with possession attribute handling 82 * 83 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 84 * defined. This is because we abuse the bottom bit of the reference to carry a 85 * flag to indicate whether the calling process possesses that key in one of 86 * its keyrings. 87 * 88 * the key_ref_t has been made a separate type so that the compiler can reject 89 * attempts to dereference it without proper conversion. 90 * 91 * the three functions are used to assemble and disassemble references 92 */ 93 typedef struct __key_reference_with_attributes *key_ref_t; 94 95 static inline key_ref_t make_key_ref(const struct key *key, 96 unsigned long possession) 97 { 98 return (key_ref_t) ((unsigned long) key | possession); 99 } 100 101 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 102 { 103 return (struct key *) ((unsigned long) key_ref & ~1UL); 104 } 105 106 static inline unsigned long is_key_possessed(const key_ref_t key_ref) 107 { 108 return (unsigned long) key_ref & 1UL; 109 } 110 111 /*****************************************************************************/ 112 /* 113 * authentication token / access credential / keyring 114 * - types of key include: 115 * - keyrings 116 * - disk encryption IDs 117 * - Kerberos TGTs and tickets 118 */ 119 struct key { 120 atomic_t usage; /* number of references */ 121 key_serial_t serial; /* key serial number */ 122 struct rb_node serial_node; 123 struct key_type *type; /* type of key */ 124 struct rw_semaphore sem; /* change vs change sem */ 125 struct key_user *user; /* owner of this key */ 126 void *security; /* security data for this key */ 127 time_t expiry; /* time at which key expires (or 0) */ 128 uid_t uid; 129 gid_t gid; 130 key_perm_t perm; /* access permissions */ 131 unsigned short quotalen; /* length added to quota */ 132 unsigned short datalen; /* payload data length 133 * - may not match RCU dereferenced payload 134 * - payload should contain own length 135 */ 136 137 #ifdef KEY_DEBUGGING 138 unsigned magic; 139 #define KEY_DEBUG_MAGIC 0x18273645u 140 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 141 #endif 142 143 unsigned long flags; /* status flags (change with bitops) */ 144 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 145 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 146 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 147 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 148 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 149 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 150 151 /* the description string 152 * - this is used to match a key against search criteria 153 * - this should be a printable string 154 * - eg: for krb5 AFS, this might be "afs (at) REDHAT.COM" 155 */ 156 char *description; 157 158 /* type specific data 159 * - this is used by the keyring type to index the name 160 */ 161 union { 162 struct list_head link; 163 } type_data; 164 165 /* key data 166 * - this is used to hold the data actually used in cryptography or 167 * whatever 168 */ 169 union { 170 unsigned long value; 171 void *data; 172 struct keyring_list *subscriptions; 173 } payload; 174 }; 175 176 /*****************************************************************************/ 177 /* 178 * kernel managed key type definition 179 */ 180 typedef int (*request_key_actor_t)(struct key *key, struct key *authkey, 181 const char *op, void *aux); 182 183 struct key_type { 184 /* name of the type */ 185 const char *name; 186 187 /* default payload length for quota precalculation (optional) 188 * - this can be used instead of calling key_payload_reserve(), that 189 * function only needs to be called if the real datalen is different 190 */ 191 size_t def_datalen; 192 193 /* instantiate a key of this type 194 * - this method should call key_payload_reserve() to determine if the 195 * user's quota will hold the payload 196 */ 197 int (*instantiate)(struct key *key, const void *data, size_t datalen); 198 199 /* update a key of this type (optional) 200 * - this method should call key_payload_reserve() to recalculate the 201 * quota consumption 202 * - the key must be locked against read when modifying 203 */ 204 int (*update)(struct key *key, const void *data, size_t datalen); 205 206 /* match a key against a description */ 207 int (*match)(const struct key *key, const void *desc); 208 209 /* clear some of the data from a key on revokation (optional) 210 * - the key's semaphore will be write-locked by the caller 211 */ 212 void (*revoke)(struct key *key); 213 214 /* clear the data from a key (optional) */ 215 void (*destroy)(struct key *key); 216 217 /* describe a key */ 218 void (*describe)(const struct key *key, struct seq_file *p); 219 220 /* read a key's data (optional) 221 * - permission checks will be done by the caller 222 * - the key's semaphore will be readlocked by the caller 223 * - should return the amount of data that could be read, no matter how 224 * much is copied into the buffer 225 * - shouldn't do the copy if the buffer is NULL 226 */ 227 long (*read)(const struct key *key, char __user *buffer, size_t buflen); 228 229 /* handle request_key() for this type instead of invoking 230 * /sbin/request-key (optional) 231 * - key is the key to instantiate 232 * - authkey is the authority to assume when instantiating this key 233 * - op is the operation to be done, usually "create" 234 * - the call must not return until the instantiation process has run 235 * its course 236 */ 237 request_key_actor_t request_key; 238 239 /* internal fields */ 240 struct list_head link; /* link in types list */ 241 }; 242 243 extern struct key_type key_type_keyring; 244 245 extern int register_key_type(struct key_type *ktype); 246 extern void unregister_key_type(struct key_type *ktype); 247 248 extern struct key *key_alloc(struct key_type *type, 249 const char *desc, 250 uid_t uid, gid_t gid, 251 struct task_struct *ctx, 252 key_perm_t perm, 253 unsigned long flags); 254 255 256 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 257 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 258 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 259 260 extern int key_payload_reserve(struct key *key, size_t datalen); 261 extern int key_instantiate_and_link(struct key *key, 262 const void *data, 263 size_t datalen, 264 struct key *keyring, 265 struct key *instkey); 266 extern int key_negate_and_link(struct key *key, 267 unsigned timeout, 268 struct key *keyring, 269 struct key *instkey); 270 extern void key_revoke(struct key *key); 271 extern void key_put(struct key *key); 272 273 static inline struct key *key_get(struct key *key) 274 { 275 if (key) 276 atomic_inc(&key->usage); 277 return key; 278 } 279 280 static inline void key_ref_put(key_ref_t key_ref) 281 { 282 key_put(key_ref_to_ptr(key_ref)); 283 } 284 285 extern struct key *request_key(struct key_type *type, 286 const char *description, 287 const char *callout_info); 288 289 extern struct key *request_key_with_auxdata(struct key_type *type, 290 const char *description, 291 const char *callout_info, 292 void *aux); 293 294 extern int key_validate(struct key *key); 295 296 extern key_ref_t key_create_or_update(key_ref_t keyring, 297 const char *type, 298 const char *description, 299 const void *payload, 300 size_t plen, 301 unsigned long flags); 302 303 extern int key_update(key_ref_t key, 304 const void *payload, 305 size_t plen); 306 307 extern int key_link(struct key *keyring, 308 struct key *key); 309 310 extern int key_unlink(struct key *keyring, 311 struct key *key); 312 313 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, 314 struct task_struct *ctx, 315 unsigned long flags, 316 struct key *dest); 317 318 extern int keyring_clear(struct key *keyring); 319 320 extern key_ref_t keyring_search(key_ref_t keyring, 321 struct key_type *type, 322 const char *description); 323 324 extern int keyring_add_key(struct key *keyring, 325 struct key *key); 326 327 extern struct key *key_lookup(key_serial_t id); 328 329 extern void keyring_replace_payload(struct key *key, void *replacement); 330 331 #define key_serial(key) ((key) ? (key)->serial : 0) 332 333 /* 334 * the userspace interface 335 */ 336 extern struct key root_user_keyring, root_session_keyring; 337 extern int alloc_uid_keyring(struct user_struct *user, 338 struct task_struct *ctx); 339 extern void switch_uid_keyring(struct user_struct *new_user); 340 extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk); 341 extern int copy_thread_group_keys(struct task_struct *tsk); 342 extern void exit_keys(struct task_struct *tsk); 343 extern void exit_thread_group_keys(struct signal_struct *tg); 344 extern int suid_keys(struct task_struct *tsk); 345 extern int exec_keys(struct task_struct *tsk); 346 extern void key_fsuid_changed(struct task_struct *tsk); 347 extern void key_fsgid_changed(struct task_struct *tsk); 348 extern void key_init(void); 349 350 #define __install_session_keyring(tsk, keyring) \ 351 ({ \ 352 struct key *old_session = tsk->signal->session_keyring; \ 353 tsk->signal->session_keyring = keyring; \ 354 old_session; \ 355 }) 356 357 #else /* CONFIG_KEYS */ 358 359 #define key_validate(k) 0 360 #define key_serial(k) 0 361 #define key_get(k) ({ NULL; }) 362 #define key_put(k) do { } while(0) 363 #define key_ref_put(k) do { } while(0) 364 #define make_key_ref(k) ({ NULL; }) 365 #define key_ref_to_ptr(k) ({ NULL; }) 366 #define is_key_possessed(k) 0 367 #define alloc_uid_keyring(u,c) 0 368 #define switch_uid_keyring(u) do { } while(0) 369 #define __install_session_keyring(t, k) ({ NULL; }) 370 #define copy_keys(f,t) 0 371 #define copy_thread_group_keys(t) 0 372 #define exit_keys(t) do { } while(0) 373 #define exit_thread_group_keys(tg) do { } while(0) 374 #define suid_keys(t) do { } while(0) 375 #define exec_keys(t) do { } while(0) 376 #define key_fsuid_changed(t) do { } while(0) 377 #define key_fsgid_changed(t) do { } while(0) 378 #define key_init() do { } while(0) 379 380 /* Initial keyrings */ 381 extern struct key root_user_keyring; 382 extern struct key root_session_keyring; 383 384 #endif /* CONFIG_KEYS */ 385 #endif /* __KERNEL__ */ 386 #endif /* _LINUX_KEY_H */ 387
