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 ([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/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_USR_VIEW 0x00010000 /* user can view a key's attributes */ 39 #define KEY_USR_READ 0x00020000 /* user can read key payload / view keyring */ 40 #define KEY_USR_WRITE 0x00040000 /* user can update key payload / add link to keyring */ 41 #define KEY_USR_SEARCH 0x00080000 /* user can find a key in search / search a keyring */ 42 #define KEY_USR_LINK 0x00100000 /* user can create a link to a key/keyring */ 43 #define KEY_USR_ALL 0x001f0000 44 45 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ 46 #define KEY_GRP_READ 0x00000200 47 #define KEY_GRP_WRITE 0x00000400 48 #define KEY_GRP_SEARCH 0x00000800 49 #define KEY_GRP_LINK 0x00001000 50 #define KEY_GRP_ALL 0x00001f00 51 52 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ 53 #define KEY_OTH_READ 0x00000002 54 #define KEY_OTH_WRITE 0x00000004 55 #define KEY_OTH_SEARCH 0x00000008 56 #define KEY_OTH_LINK 0x00000010 57 #define KEY_OTH_ALL 0x0000001f 58 59 struct seq_file; 60 struct user_struct; 61 struct signal_struct; 62 63 struct key_type; 64 struct key_owner; 65 struct keyring_list; 66 struct keyring_name; 67 68 /*****************************************************************************/ 69 /* 70 * authentication token / access credential / keyring 71 * - types of key include: 72 * - keyrings 73 * - disk encryption IDs 74 * - Kerberos TGTs and tickets 75 */ 76 struct key { 77 atomic_t usage; /* number of references */ 78 key_serial_t serial; /* key serial number */ 79 struct rb_node serial_node; 80 struct key_type *type; /* type of key */ 81 struct rw_semaphore sem; /* change vs change sem */ 82 struct key_user *user; /* owner of this key */ 83 time_t expiry; /* time at which key expires (or 0) */ 84 uid_t uid; 85 gid_t gid; 86 key_perm_t perm; /* access permissions */ 87 unsigned short quotalen; /* length added to quota */ 88 unsigned short datalen; /* payload data length 89 * - may not match RCU dereferenced payload 90 * - payload should contain own length 91 */ 92 93 #ifdef KEY_DEBUGGING 94 unsigned magic; 95 #define KEY_DEBUG_MAGIC 0x18273645u 96 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 97 #endif 98 99 unsigned long flags; /* status flags (change with bitops) */ 100 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 101 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 102 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 103 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 104 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 105 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 106 107 /* the description string 108 * - this is used to match a key against search criteria 109 * - this should be a printable string 110 * - eg: for krb5 AFS, this might be "[email protected]" 111 */ 112 char *description; 113 114 /* type specific data 115 * - this is used by the keyring type to index the name 116 */ 117 union { 118 struct list_head link; 119 } type_data; 120 121 /* key data 122 * - this is used to hold the data actually used in cryptography or 123 * whatever 124 */ 125 union { 126 unsigned long value; 127 void *data; 128 struct keyring_list *subscriptions; 129 } payload; 130 }; 131 132 /*****************************************************************************/ 133 /* 134 * kernel managed key type definition 135 */ 136 struct key_type { 137 /* name of the type */ 138 const char *name; 139 140 /* default payload length for quota precalculation (optional) 141 * - this can be used instead of calling key_payload_reserve(), that 142 * function only needs to be called if the real datalen is different 143 */ 144 size_t def_datalen; 145 146 /* instantiate a key of this type 147 * - this method should call key_payload_reserve() to determine if the 148 * user's quota will hold the payload 149 */ 150 int (*instantiate)(struct key *key, const void *data, size_t datalen); 151 152 /* duplicate a key of this type (optional) 153 * - the source key will be locked against change 154 * - the new description will be attached 155 * - the quota will have been adjusted automatically from 156 * source->quotalen 157 */ 158 int (*duplicate)(struct key *key, const struct key *source); 159 160 /* update a key of this type (optional) 161 * - this method should call key_payload_reserve() to recalculate the 162 * quota consumption 163 * - the key must be locked against read when modifying 164 */ 165 int (*update)(struct key *key, const void *data, size_t datalen); 166 167 /* match a key against a description */ 168 int (*match)(const struct key *key, const void *desc); 169 170 /* clear the data from a key (optional) */ 171 void (*destroy)(struct key *key); 172 173 /* describe a key */ 174 void (*describe)(const struct key *key, struct seq_file *p); 175 176 /* read a key's data (optional) 177 * - permission checks will be done by the caller 178 * - the key's semaphore will be readlocked by the caller 179 * - should return the amount of data that could be read, no matter how 180 * much is copied into the buffer 181 * - shouldn't do the copy if the buffer is NULL 182 */ 183 long (*read)(const struct key *key, char __user *buffer, size_t buflen); 184 185 /* internal fields */ 186 struct list_head link; /* link in types list */ 187 }; 188 189 extern struct key_type key_type_keyring; 190 191 extern int register_key_type(struct key_type *ktype); 192 extern void unregister_key_type(struct key_type *ktype); 193 194 extern struct key *key_alloc(struct key_type *type, 195 const char *desc, 196 uid_t uid, gid_t gid, key_perm_t perm, 197 int not_in_quota); 198 extern int key_payload_reserve(struct key *key, size_t datalen); 199 extern int key_instantiate_and_link(struct key *key, 200 const void *data, 201 size_t datalen, 202 struct key *keyring, 203 struct key *instkey); 204 extern int key_negate_and_link(struct key *key, 205 unsigned timeout, 206 struct key *keyring, 207 struct key *instkey); 208 extern void key_revoke(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 extern struct key *request_key(struct key_type *type, 219 const char *description, 220 const char *callout_info); 221 222 extern int key_validate(struct key *key); 223 224 extern struct key *key_create_or_update(struct key *keyring, 225 const char *type, 226 const char *description, 227 const void *payload, 228 size_t plen, 229 int not_in_quota); 230 231 extern int key_update(struct key *key, 232 const void *payload, 233 size_t plen); 234 235 extern int key_link(struct key *keyring, 236 struct key *key); 237 238 extern int key_unlink(struct key *keyring, 239 struct key *key); 240 241 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, 242 int not_in_quota, struct key *dest); 243 244 extern int keyring_clear(struct key *keyring); 245 246 extern struct key *keyring_search(struct key *keyring, 247 struct key_type *type, 248 const char *description); 249 250 extern int keyring_add_key(struct key *keyring, 251 struct key *key); 252 253 extern struct key *key_lookup(key_serial_t id); 254 255 extern void keyring_replace_payload(struct key *key, void *replacement); 256 257 #define key_serial(key) ((key) ? (key)->serial : 0) 258 259 /* 260 * the userspace interface 261 */ 262 extern struct key root_user_keyring, root_session_keyring; 263 extern int alloc_uid_keyring(struct user_struct *user); 264 extern void switch_uid_keyring(struct user_struct *new_user); 265 extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk); 266 extern int copy_thread_group_keys(struct task_struct *tsk); 267 extern void exit_keys(struct task_struct *tsk); 268 extern void exit_thread_group_keys(struct signal_struct *tg); 269 extern int suid_keys(struct task_struct *tsk); 270 extern int exec_keys(struct task_struct *tsk); 271 extern void key_fsuid_changed(struct task_struct *tsk); 272 extern void key_fsgid_changed(struct task_struct *tsk); 273 extern void key_init(void); 274 275 #define __install_session_keyring(tsk, keyring) \ 276 ({ \ 277 struct key *old_session = tsk->signal->session_keyring; \ 278 tsk->signal->session_keyring = keyring; \ 279 old_session; \ 280 }) 281 282 #else /* CONFIG_KEYS */ 283 284 #define key_validate(k) 0 285 #define key_serial(k) 0 286 #define key_get(k) ({ NULL; }) 287 #define key_put(k) do { } while(0) 288 #define alloc_uid_keyring(u) 0 289 #define switch_uid_keyring(u) do { } while(0) 290 #define __install_session_keyring(t, k) ({ NULL; }) 291 #define copy_keys(f,t) 0 292 #define copy_thread_group_keys(t) 0 293 #define exit_keys(t) do { } while(0) 294 #define exit_thread_group_keys(tg) do { } while(0) 295 #define suid_keys(t) do { } while(0) 296 #define exec_keys(t) do { } while(0) 297 #define key_fsuid_changed(t) do { } while(0) 298 #define key_fsgid_changed(t) do { } while(0) 299 #define key_init() do { } while(0) 300 301 #endif /* CONFIG_KEYS */ 302 #endif /* __KERNEL__ */ 303 #endif /* _LINUX_KEY_H */ 304