| 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 | |
| 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 | #define KEY_FLAG_UID_KEYRING 11 /* set if key is a user or user session keyring */ |
| 166 | |
| 167 | /* the description string |
| 168 | * - this is used to match a key against search criteria |
| 169 | * - this should be a printable string |
| 170 | * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" |
| 171 | */ |
| 172 | char *description; |
| 173 | |
| 174 | /* type specific data |
| 175 | * - this is used by the keyring type to index the name |
| 176 | */ |
| 177 | union { |
| 178 | struct list_head link; |
| 179 | unsigned long x[2]; |
| 180 | void *p[2]; |
| 181 | int reject_error; |
| 182 | } type_data; |
| 183 | |
| 184 | /* key data |
| 185 | * - this is used to hold the data actually used in cryptography or |
| 186 | * whatever |
| 187 | */ |
| 188 | union { |
| 189 | unsigned long value; |
| 190 | void __rcu *rcudata; |
| 191 | void *data; |
| 192 | struct keyring_list __rcu *subscriptions; |
| 193 | } payload; |
| 194 | }; |
| 195 | |
| 196 | extern struct key *key_alloc(struct key_type *type, |
| 197 | const char *desc, |
| 198 | kuid_t uid, kgid_t gid, |
| 199 | const struct cred *cred, |
| 200 | key_perm_t perm, |
| 201 | unsigned long flags); |
| 202 | |
| 203 | |
| 204 | #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ |
| 205 | #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ |
| 206 | #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ |
| 207 | #define KEY_ALLOC_UID_KEYRING 0x0010 /* allocating a user or user session keyring */ |
| 208 | |
| 209 | extern void key_revoke(struct key *key); |
| 210 | extern void key_invalidate(struct key *key); |
| 211 | extern void key_put(struct key *key); |
| 212 | |
| 213 | static inline struct key *key_get(struct key *key) |
| 214 | { |
| 215 | if (key) |
| 216 | atomic_inc(&key->usage); |
| 217 | return key; |
| 218 | } |
| 219 | |
| 220 | static inline void key_ref_put(key_ref_t key_ref) |
| 221 | { |
| 222 | key_put(key_ref_to_ptr(key_ref)); |
| 223 | } |
| 224 | |
| 225 | extern struct key *request_key(struct key_type *type, |
| 226 | const char *description, |
| 227 | const char *callout_info); |
| 228 | |
| 229 | extern struct key *request_key_with_auxdata(struct key_type *type, |
| 230 | const char *description, |
| 231 | const void *callout_info, |
| 232 | size_t callout_len, |
| 233 | void *aux); |
| 234 | |
| 235 | extern struct key *request_key_async(struct key_type *type, |
| 236 | const char *description, |
| 237 | const void *callout_info, |
| 238 | size_t callout_len); |
| 239 | |
| 240 | extern struct key *request_key_async_with_auxdata(struct key_type *type, |
| 241 | const char *description, |
| 242 | const void *callout_info, |
| 243 | size_t callout_len, |
| 244 | void *aux); |
| 245 | |
| 246 | extern int wait_for_key_construction(struct key *key, bool intr); |
| 247 | |
| 248 | extern int key_validate(const struct key *key); |
| 249 | |
| 250 | extern key_ref_t key_create_or_update(key_ref_t keyring, |
| 251 | const char *type, |
| 252 | const char *description, |
| 253 | const void *payload, |
| 254 | size_t plen, |
| 255 | key_perm_t perm, |
| 256 | unsigned long flags); |
| 257 | |
| 258 | extern int key_update(key_ref_t key, |
| 259 | const void *payload, |
| 260 | size_t plen); |
| 261 | |
| 262 | extern int key_link(struct key *keyring, |
| 263 | struct key *key); |
| 264 | |
| 265 | extern int key_unlink(struct key *keyring, |
| 266 | struct key *key); |
| 267 | |
| 268 | extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
| 269 | const struct cred *cred, |
| 270 | key_perm_t perm, |
| 271 | unsigned long flags, |
| 272 | struct key *dest); |
| 273 | |
| 274 | extern int keyring_clear(struct key *keyring); |
| 275 | |
| 276 | extern key_ref_t keyring_search(key_ref_t keyring, |
| 277 | struct key_type *type, |
| 278 | const char *description); |
| 279 | |
| 280 | extern int keyring_add_key(struct key *keyring, |
| 281 | struct key *key); |
| 282 | |
| 283 | extern struct key *key_lookup(key_serial_t id); |
| 284 | |
| 285 | static inline key_serial_t key_serial(const struct key *key) |
| 286 | { |
| 287 | return key ? key->serial : 0; |
| 288 | } |
| 289 | |
| 290 | extern void key_set_timeout(struct key *, unsigned); |
| 291 | |
| 292 | /** |
| 293 | * key_is_instantiated - Determine if a key has been positively instantiated |
| 294 | * @key: The key to check. |
| 295 | * |
| 296 | * Return true if the specified key has been positively instantiated, false |
| 297 | * otherwise. |
| 298 | */ |
| 299 | static inline bool key_is_instantiated(const struct key *key) |
| 300 | { |
| 301 | return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && |
| 302 | !test_bit(KEY_FLAG_NEGATIVE, &key->flags); |
| 303 | } |
| 304 | |
| 305 | #define rcu_dereference_key(KEY) \ |
| 306 | (rcu_dereference_protected((KEY)->payload.rcudata, \ |
| 307 | rwsem_is_locked(&((struct key *)(KEY))->sem))) |
| 308 | |
| 309 | #define rcu_assign_keypointer(KEY, PAYLOAD) \ |
| 310 | do { \ |
| 311 | rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \ |
| 312 | } while (0) |
| 313 | |
| 314 | #ifdef CONFIG_SYSCTL |
| 315 | extern ctl_table key_sysctls[]; |
| 316 | #endif |
| 317 | /* |
| 318 | * the userspace interface |
| 319 | */ |
| 320 | extern int install_thread_keyring_to_cred(struct cred *cred); |
| 321 | extern void key_fsuid_changed(struct task_struct *tsk); |
| 322 | extern void key_fsgid_changed(struct task_struct *tsk); |
| 323 | extern void key_init(void); |
| 324 | |
| 325 | #else /* CONFIG_KEYS */ |
| 326 | |
| 327 | #define key_validate(k) 0 |
| 328 | #define key_serial(k) 0 |
| 329 | #define key_get(k) ({ NULL; }) |
| 330 | #define key_revoke(k) do { } while(0) |
| 331 | #define key_invalidate(k) do { } while(0) |
| 332 | #define key_put(k) do { } while(0) |
| 333 | #define key_ref_put(k) do { } while(0) |
| 334 | #define make_key_ref(k, p) NULL |
| 335 | #define key_ref_to_ptr(k) NULL |
| 336 | #define is_key_possessed(k) 0 |
| 337 | #define key_fsuid_changed(t) do { } while(0) |
| 338 | #define key_fsgid_changed(t) do { } while(0) |
| 339 | #define key_init() do { } while(0) |
| 340 | |
| 341 | #endif /* CONFIG_KEYS */ |
| 342 | #endif /* __KERNEL__ */ |
| 343 | #endif /* _LINUX_KEY_H */ |