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 struct rb_node serial_node; 128 struct key_type *type; /* type of key */ 129 struct rw_semaphore sem; /* change vs change sem */ 130 struct key_user *user; /* owner of this key */ 131 void *security; /* security data for this key */ 132 union { 133 time_t expiry; /* time at which key expires (or 0) */ 134 time_t revoked_at; /* time at which key was revoked */ 135 }; 136 uid_t uid; 137 gid_t gid; 138 key_perm_t perm; /* access permissions */ 139 unsigned short quotalen; /* length added to quota */ 140 unsigned short datalen; /* payload data length 141 * - may not match RCU dereferenced payload 142 * - payload should contain own length 143 */ 144 145 #ifdef KEY_DEBUGGING 146 unsigned magic; 147 #define KEY_DEBUG_MAGIC 0x18273645u 148 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 149 #endif 150 151 unsigned long flags; /* status flags (change with bitops) */ 152 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 153 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 154 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 155 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 156 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 157 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 158 159 /* the description string 160 * - this is used to match a key against search criteria 161 * - this should be a printable string 162 * - eg: for krb5 AFS, this might be "[email protected]" 163 */ 164 char *description; 165 166 /* type specific data 167 * - this is used by the keyring type to index the name 168 */ 169 union { 170 struct list_head link; 171 unsigned long x[2]; 172 void *p[2]; 173 int reject_error; 174 } type_data; 175 176 /* key data 177 * - this is used to hold the data actually used in cryptography or 178 * whatever 179 */ 180 union { 181 unsigned long value; 182 void __rcu *rcudata; 183 void *data; 184 struct keyring_list __rcu *subscriptions; 185 } payload; 186 }; 187 188 extern struct key *key_alloc(struct key_type *type, 189 const char *desc, 190 uid_t uid, gid_t gid, 191 const struct cred *cred, 192 key_perm_t perm, 193 unsigned long flags); 194 195 196 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 197 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 198 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 199 200 extern void key_revoke(struct key *key); 201 extern void key_put(struct key *key); 202 203 static inline struct key *key_get(struct key *key) 204 { 205 if (key) 206 atomic_inc(&key->usage); 207 return key; 208 } 209 210 static inline void key_ref_put(key_ref_t key_ref) 211 { 212 key_put(key_ref_to_ptr(key_ref)); 213 } 214 215 extern struct key *request_key(struct key_type *type, 216 const char *description, 217 const char *callout_info); 218 219 extern struct key *request_key_with_auxdata(struct key_type *type, 220 const char *description, 221 const void *callout_info, 222 size_t callout_len, 223 void *aux); 224 225 extern struct key *request_key_async(struct key_type *type, 226 const char *description, 227 const void *callout_info, 228 size_t callout_len); 229 230 extern struct key *request_key_async_with_auxdata(struct key_type *type, 231 const char *description, 232 const void *callout_info, 233 size_t callout_len, 234 void *aux); 235 236 extern int wait_for_key_construction(struct key *key, bool intr); 237 238 extern int key_validate(struct key *key); 239 240 extern key_ref_t key_create_or_update(key_ref_t keyring, 241 const char *type, 242 const char *description, 243 const void *payload, 244 size_t plen, 245 key_perm_t perm, 246 unsigned long flags); 247 248 extern int key_update(key_ref_t key, 249 const void *payload, 250 size_t plen); 251 252 extern int key_link(struct key *keyring, 253 struct key *key); 254 255 extern int key_unlink(struct key *keyring, 256 struct key *key); 257 258 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, 259 const struct cred *cred, 260 unsigned long flags, 261 struct key *dest); 262 263 extern int keyring_clear(struct key *keyring); 264 265 extern key_ref_t keyring_search(key_ref_t keyring, 266 struct key_type *type, 267 const char *description); 268 269 extern int keyring_add_key(struct key *keyring, 270 struct key *key); 271 272 extern struct key *key_lookup(key_serial_t id); 273 274 static inline key_serial_t key_serial(const struct key *key) 275 { 276 return key ? key->serial : 0; 277 } 278 279 /** 280 * key_is_instantiated - Determine if a key has been positively instantiated 281 * @key: The key to check. 282 * 283 * Return true if the specified key has been positively instantiated, false 284 * otherwise. 285 */ 286 static inline bool key_is_instantiated(const struct key *key) 287 { 288 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && 289 !test_bit(KEY_FLAG_NEGATIVE, &key->flags); 290 } 291 292 #define rcu_dereference_key(KEY) \ 293 (rcu_dereference_protected((KEY)->payload.rcudata, \ 294 rwsem_is_locked(&((struct key *)(KEY))->sem))) 295 296 #define rcu_assign_keypointer(KEY, PAYLOAD) \ 297 (rcu_assign_pointer((KEY)->payload.rcudata, PAYLOAD)) 298 299 #ifdef CONFIG_SYSCTL 300 extern ctl_table key_sysctls[]; 301 #endif 302 303 extern void key_replace_session_keyring(void); 304 305 /* 306 * the userspace interface 307 */ 308 extern int install_thread_keyring_to_cred(struct cred *cred); 309 extern void key_fsuid_changed(struct task_struct *tsk); 310 extern void key_fsgid_changed(struct task_struct *tsk); 311 extern void key_init(void); 312 313 #else /* CONFIG_KEYS */ 314 315 #define key_validate(k) 0 316 #define key_serial(k) 0 317 #define key_get(k) ({ NULL; }) 318 #define key_revoke(k) do { } while(0) 319 #define key_put(k) do { } while(0) 320 #define key_ref_put(k) do { } while(0) 321 #define make_key_ref(k, p) NULL 322 #define key_ref_to_ptr(k) NULL 323 #define is_key_possessed(k) 0 324 #define key_fsuid_changed(t) do { } while(0) 325 #define key_fsgid_changed(t) do { } while(0) 326 #define key_init() do { } while(0) 327 #define key_replace_session_keyring() do { } while(0) 328 329 #endif /* CONFIG_KEYS */ 330 #endif /* __KERNEL__ */ 331 #endif /* _LINUX_KEY_H */ 332