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 #include <linux/uidgid.h> 28 29 /* key handle serial number */ 30 typedef int32_t key_serial_t; 31 32 /* key handle permissions mask */ 33 typedef uint32_t key_perm_t; 34 35 struct key; 36 37 #ifdef CONFIG_KEYS 38 39 #undef KEY_DEBUGGING 40 41 #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */ 42 #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */ 43 #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */ 44 #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */ 45 #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */ 46 #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */ 47 #define KEY_POS_ALL 0x3f000000 48 49 #define KEY_USR_VIEW 0x00010000 /* user permissions... */ 50 #define KEY_USR_READ 0x00020000 51 #define KEY_USR_WRITE 0x00040000 52 #define KEY_USR_SEARCH 0x00080000 53 #define KEY_USR_LINK 0x00100000 54 #define KEY_USR_SETATTR 0x00200000 55 #define KEY_USR_ALL 0x003f0000 56 57 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ 58 #define KEY_GRP_READ 0x00000200 59 #define KEY_GRP_WRITE 0x00000400 60 #define KEY_GRP_SEARCH 0x00000800 61 #define KEY_GRP_LINK 0x00001000 62 #define KEY_GRP_SETATTR 0x00002000 63 #define KEY_GRP_ALL 0x00003f00 64 65 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ 66 #define KEY_OTH_READ 0x00000002 67 #define KEY_OTH_WRITE 0x00000004 68 #define KEY_OTH_SEARCH 0x00000008 69 #define KEY_OTH_LINK 0x00000010 70 #define KEY_OTH_SETATTR 0x00000020 71 #define KEY_OTH_ALL 0x0000003f 72 73 #define KEY_PERM_UNDEF 0xffffffff 74 75 struct seq_file; 76 struct user_struct; 77 struct signal_struct; 78 struct cred; 79 80 struct key_type; 81 struct key_owner; 82 struct keyring_list; 83 struct keyring_name; 84 85 /*****************************************************************************/ 86 /* 87 * key reference with possession attribute handling 88 * 89 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 90 * defined. This is because we abuse the bottom bit of the reference to carry a 91 * flag to indicate whether the calling process possesses that key in one of 92 * its keyrings. 93 * 94 * the key_ref_t has been made a separate type so that the compiler can reject 95 * attempts to dereference it without proper conversion. 96 * 97 * the three functions are used to assemble and disassemble references 98 */ 99 typedef struct __key_reference_with_attributes *key_ref_t; 100 101 static inline key_ref_t make_key_ref(const struct key *key, 102 unsigned long possession) 103 { 104 return (key_ref_t) ((unsigned long) key | possession); 105 } 106 107 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 108 { 109 return (struct key *) ((unsigned long) key_ref & ~1UL); 110 } 111 112 static inline unsigned long is_key_possessed(const key_ref_t key_ref) 113 { 114 return (unsigned long) key_ref & 1UL; 115 } 116 117 /*****************************************************************************/ 118 /* 119 * authentication token / access credential / keyring 120 * - types of key include: 121 * - keyrings 122 * - disk encryption IDs 123 * - Kerberos TGTs and tickets 124 */ 125 struct key { 126 atomic_t usage; /* number of references */ 127 key_serial_t serial; /* key serial number */ 128 union { 129 struct list_head graveyard_link; 130 struct rb_node serial_node; 131 }; 132 struct key_type *type; /* type of key */ 133 struct rw_semaphore sem; /* change vs change sem */ 134 struct key_user *user; /* owner of this key */ 135 void *security; /* security data for this key */ 136 union { 137 time_t expiry; /* time at which key expires (or 0) */ 138 time_t revoked_at; /* time at which key was revoked */ 139 }; 140 time_t last_used_at; /* last time used for LRU keyring discard */ 141 kuid_t uid; 142 kgid_t gid; 143 key_perm_t perm; /* access permissions */ 144 unsigned short quotalen; /* length added to quota */ 145 unsigned short datalen; /* payload data length 146 * - may not match RCU dereferenced payload 147 * - payload should contain own length 148 */ 149 150 #ifdef KEY_DEBUGGING 151 unsigned magic; 152 #define KEY_DEBUG_MAGIC 0x18273645u 153 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 154 #endif 155 156 unsigned long flags; /* status flags (change with bitops) */ 157 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 158 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 159 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 160 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 161 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 162 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 163 #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ 164 #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ 165 166 /* the description string 167 * - this is used to match a key against search criteria 168 * - this should be a printable string 169 * - eg: for krb5 AFS, this might be "[email protected]" 170 */ 171 char *description; 172 173 /* type specific data 174 * - this is used by the keyring type to index the name 175 */ 176 union { 177 struct list_head link; 178 unsigned long x[2]; 179 void *p[2]; 180 int reject_error; 181 } type_data; 182 183 /* key data 184 * - this is used to hold the data actually used in cryptography or 185 * whatever 186 */ 187 union { 188 unsigned long value; 189 void __rcu *rcudata; 190 void *data; 191 struct keyring_list __rcu *subscriptions; 192 } payload; 193 }; 194 195 extern struct key *key_alloc(struct key_type *type, 196 const char *desc, 197 kuid_t uid, kgid_t gid, 198 const struct cred *cred, 199 key_perm_t perm, 200 unsigned long flags); 201 202 203 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 204 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 205 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 206 207 extern void key_revoke(struct key *key); 208 extern void key_invalidate(struct key *key); 209 extern void key_put(struct key *key); 210 211 static inline struct key *key_get(struct key *key) 212 { 213 if (key) 214 atomic_inc(&key->usage); 215 return key; 216 } 217 218 static inline void key_ref_put(key_ref_t key_ref) 219 { 220 key_put(key_ref_to_ptr(key_ref)); 221 } 222 223 extern struct key *request_key(struct key_type *type, 224 const char *description, 225 const char *callout_info); 226 227 extern struct key *request_key_with_auxdata(struct key_type *type, 228 const char *description, 229 const void *callout_info, 230 size_t callout_len, 231 void *aux); 232 233 extern struct key *request_key_async(struct key_type *type, 234 const char *description, 235 const void *callout_info, 236 size_t callout_len); 237 238 extern struct key *request_key_async_with_auxdata(struct key_type *type, 239 const char *description, 240 const void *callout_info, 241 size_t callout_len, 242 void *aux); 243 244 extern int wait_for_key_construction(struct key *key, bool intr); 245 246 extern int key_validate(const struct key *key); 247 248 extern key_ref_t key_create_or_update(key_ref_t keyring, 249 const char *type, 250 const char *description, 251 const void *payload, 252 size_t plen, 253 key_perm_t perm, 254 unsigned long flags); 255 256 extern int key_update(key_ref_t key, 257 const void *payload, 258 size_t plen); 259 260 extern int key_link(struct key *keyring, 261 struct key *key); 262 263 extern int key_unlink(struct key *keyring, 264 struct key *key); 265 266 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, 267 const struct cred *cred, 268 key_perm_t perm, 269 unsigned long flags, 270 struct key *dest); 271 272 extern int keyring_clear(struct key *keyring); 273 274 extern key_ref_t keyring_search(key_ref_t keyring, 275 struct key_type *type, 276 const char *description); 277 278 extern int keyring_add_key(struct key *keyring, 279 struct key *key); 280 281 extern struct key *key_lookup(key_serial_t id); 282 283 static inline key_serial_t key_serial(const struct key *key) 284 { 285 return key ? key->serial : 0; 286 } 287 288 extern void key_set_timeout(struct key *, unsigned); 289 290 /** 291 * key_is_instantiated - Determine if a key has been positively instantiated 292 * @key: The key to check. 293 * 294 * Return true if the specified key has been positively instantiated, false 295 * otherwise. 296 */ 297 static inline bool key_is_instantiated(const struct key *key) 298 { 299 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && 300 !test_bit(KEY_FLAG_NEGATIVE, &key->flags); 301 } 302 303 #define rcu_dereference_key(KEY) \ 304 (rcu_dereference_protected((KEY)->payload.rcudata, \ 305 rwsem_is_locked(&((struct key *)(KEY))->sem))) 306 307 #define rcu_assign_keypointer(KEY, PAYLOAD) \ 308 do { \ 309 rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \ 310 } while (0) 311 312 #ifdef CONFIG_SYSCTL 313 extern ctl_table key_sysctls[]; 314 #endif 315 /* 316 * the userspace interface 317 */ 318 extern int install_thread_keyring_to_cred(struct cred *cred); 319 extern void key_fsuid_changed(struct task_struct *tsk); 320 extern void key_fsgid_changed(struct task_struct *tsk); 321 extern void key_init(void); 322 323 #else /* CONFIG_KEYS */ 324 325 #define key_validate(k) 0 326 #define key_serial(k) 0 327 #define key_get(k) ({ NULL; }) 328 #define key_revoke(k) do { } while(0) 329 #define key_invalidate(k) do { } while(0) 330 #define key_put(k) do { } while(0) 331 #define key_ref_put(k) do { } while(0) 332 #define make_key_ref(k, p) NULL 333 #define key_ref_to_ptr(k) NULL 334 #define is_key_possessed(k) 0 335 #define key_fsuid_changed(t) do { } while(0) 336 #define key_fsgid_changed(t) do { } while(0) 337 #define key_init() do { } while(0) 338 339 #endif /* CONFIG_KEYS */ 340 #endif /* __KERNEL__ */ 341 #endif /* _LINUX_KEY_H */ 342