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 26 #ifdef __KERNEL__ 27 28 /* key handle serial number */ 29 typedef int32_t key_serial_t; 30 31 /* key handle permissions mask */ 32 typedef uint32_t key_perm_t; 33 34 struct key; 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 keyring_list; 82 struct keyring_name; 83 84 /*****************************************************************************/ 85 /* 86 * key reference with possession attribute handling 87 * 88 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 89 * defined. This is because we abuse the bottom bit of the reference to carry a 90 * flag to indicate whether the calling process possesses that key in one of 91 * its keyrings. 92 * 93 * the key_ref_t has been made a separate type so that the compiler can reject 94 * attempts to dereference it without proper conversion. 95 * 96 * the three functions are used to assemble and disassemble references 97 */ 98 typedef struct __key_reference_with_attributes *key_ref_t; 99 100 static inline key_ref_t make_key_ref(const struct key *key, 101 unsigned long possession) 102 { 103 return (key_ref_t) ((unsigned long) key | possession); 104 } 105 106 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 107 { 108 return (struct key *) ((unsigned long) key_ref & ~1UL); 109 } 110 111 static inline unsigned long is_key_possessed(const key_ref_t key_ref) 112 { 113 return (unsigned long) key_ref & 1UL; 114 } 115 116 /*****************************************************************************/ 117 /* 118 * authentication token / access credential / keyring 119 * - types of key include: 120 * - keyrings 121 * - disk encryption IDs 122 * - Kerberos TGTs and tickets 123 */ 124 struct key { 125 atomic_t usage; /* number of references */ 126 key_serial_t serial; /* key serial number */ 127 union { 128 struct list_head graveyard_link; 129 struct rb_node serial_node; 130 }; 131 struct key_type *type; /* type of key */ 132 struct rw_semaphore sem; /* change vs change sem */ 133 struct key_user *user; /* owner of this key */ 134 void *security; /* security data for this key */ 135 union { 136 time_t expiry; /* time at which key expires (or 0) */ 137 time_t revoked_at; /* time at which key was revoked */ 138 }; 139 time_t last_used_at; /* last time used for LRU keyring discard */ 140 uid_t uid; 141 gid_t gid; 142 key_perm_t perm; /* access permissions */ 143 unsigned short quotalen; /* length added to quota */ 144 unsigned short datalen; /* payload data length 145 * - may not match RCU dereferenced payload 146 * - payload should contain own length 147 */ 148 149 #ifdef KEY_DEBUGGING 150 unsigned magic; 151 #define KEY_DEBUG_MAGIC 0x18273645u 152 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 153 #endif 154 155 unsigned long flags; /* status flags (change with bitops) */ 156 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 157 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 158 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 159 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 160 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 161 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 162 #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ 163 #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ 164 165 /* the description string 166 * - this is used to match a key against search criteria 167 * - this should be a printable string 168 * - eg: for krb5 AFS, this might be "[email protected]" 169 */ 170 char *description; 171 172 /* type specific data 173 * - this is used by the keyring type to index the name 174 */ 175 union { 176 struct list_head link; 177 unsigned long x[2]; 178 void *p[2]; 179 int reject_error; 180 } type_data; 181 182 /* key data 183 * - this is used to hold the data actually used in cryptography or 184 * whatever 185 */ 186 union { 187 unsigned long value; 188 void __rcu *rcudata; 189 void *data; 190 struct keyring_list __rcu *subscriptions; 191 } payload; 192 }; 193 194 extern struct key *key_alloc(struct key_type *type, 195 const char *desc, 196 uid_t uid, gid_t gid, 197 const struct cred *cred, 198 key_perm_t perm, 199 unsigned long flags); 200 201 202 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 203 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 204 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 205 206 extern void key_revoke(struct key *key); 207 extern void key_invalidate(struct key *key); 208 extern void key_put(struct key *key); 209 210 static inline struct key *key_get(struct key *key) 211 { 212 if (key) 213 atomic_inc(&key->usage); 214 return key; 215 } 216 217 static inline void key_ref_put(key_ref_t key_ref) 218 { 219 key_put(key_ref_to_ptr(key_ref)); 220 } 221 222 extern struct key *request_key(struct key_type *type, 223 const char *description, 224 const char *callout_info); 225 226 extern struct key *request_key_with_auxdata(struct key_type *type, 227 const char *description, 228 const void *callout_info, 229 size_t callout_len, 230 void *aux); 231 232 extern struct key *request_key_async(struct key_type *type, 233 const char *description, 234 const void *callout_info, 235 size_t callout_len); 236 237 extern struct key *request_key_async_with_auxdata(struct key_type *type, 238 const char *description, 239 const void *callout_info, 240 size_t callout_len, 241 void *aux); 242 243 extern int wait_for_key_construction(struct key *key, bool intr); 244 245 extern int key_validate(const struct key *key); 246 247 extern key_ref_t key_create_or_update(key_ref_t keyring, 248 const char *type, 249 const char *description, 250 const void *payload, 251 size_t plen, 252 key_perm_t perm, 253 unsigned long flags); 254 255 extern int key_update(key_ref_t key, 256 const void *payload, 257 size_t plen); 258 259 extern int key_link(struct key *keyring, 260 struct key *key); 261 262 extern int key_unlink(struct key *keyring, 263 struct key *key); 264 265 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, 266 const struct cred *cred, 267 unsigned long flags, 268 struct key *dest); 269 270 extern int keyring_clear(struct key *keyring); 271 272 extern key_ref_t keyring_search(key_ref_t keyring, 273 struct key_type *type, 274 const char *description); 275 276 extern int keyring_add_key(struct key *keyring, 277 struct key *key); 278 279 extern struct key *key_lookup(key_serial_t id); 280 281 static inline key_serial_t key_serial(const struct key *key) 282 { 283 return key ? key->serial : 0; 284 } 285 286 extern void key_set_timeout(struct key *, unsigned); 287 288 /** 289 * key_is_instantiated - Determine if a key has been positively instantiated 290 * @key: The key to check. 291 * 292 * Return true if the specified key has been positively instantiated, false 293 * otherwise. 294 */ 295 static inline bool key_is_instantiated(const struct key *key) 296 { 297 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && 298 !test_bit(KEY_FLAG_NEGATIVE, &key->flags); 299 } 300 301 #define rcu_dereference_key(KEY) \ 302 (rcu_dereference_protected((KEY)->payload.rcudata, \ 303 rwsem_is_locked(&((struct key *)(KEY))->sem))) 304 305 #define rcu_assign_keypointer(KEY, PAYLOAD) \ 306 do { \ 307 rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \ 308 } while (0) 309 310 #ifdef CONFIG_SYSCTL 311 extern ctl_table key_sysctls[]; 312 #endif 313 /* 314 * the userspace interface 315 */ 316 extern int install_thread_keyring_to_cred(struct cred *cred); 317 extern void key_fsuid_changed(struct task_struct *tsk); 318 extern void key_fsgid_changed(struct task_struct *tsk); 319 extern void key_init(void); 320 321 #else /* CONFIG_KEYS */ 322 323 #define key_validate(k) 0 324 #define key_serial(k) 0 325 #define key_get(k) ({ NULL; }) 326 #define key_revoke(k) do { } while(0) 327 #define key_invalidate(k) do { } while(0) 328 #define key_put(k) do { } while(0) 329 #define key_ref_put(k) do { } while(0) 330 #define make_key_ref(k, p) NULL 331 #define key_ref_to_ptr(k) NULL 332 #define is_key_possessed(k) 0 333 #define key_fsuid_changed(t) do { } while(0) 334 #define key_fsgid_changed(t) do { } while(0) 335 #define key_init() do { } while(0) 336 337 #endif /* CONFIG_KEYS */ 338 #endif /* __KERNEL__ */ 339 #endif /* _LINUX_KEY_H */ 340