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/spinlock.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 rwlock_t lock; /* examination vs change lock */ 82 struct rw_semaphore sem; /* change vs change sem */ 83 struct key_user *user; /* owner of this key */ 84 time_t expiry; /* time at which key expires (or 0) */ 85 uid_t uid; 86 gid_t gid; 87 key_perm_t perm; /* access permissions */ 88 unsigned short quotalen; /* length added to quota */ 89 unsigned short datalen; /* payload data length */ 90 unsigned short flags; /* status flags (change with lock writelocked) */ 91 #define KEY_FLAG_INSTANTIATED 0x00000001 /* set if key has been instantiated */ 92 #define KEY_FLAG_DEAD 0x00000002 /* set if key type has been deleted */ 93 #define KEY_FLAG_REVOKED 0x00000004 /* set if key had been revoked */ 94 #define KEY_FLAG_IN_QUOTA 0x00000008 /* set if key consumes quota */ 95 #define KEY_FLAG_USER_CONSTRUCT 0x00000010 /* set if key is being constructed in userspace */ 96 #define KEY_FLAG_NEGATIVE 0x00000020 /* set if key is negative */ 97 98 #ifdef KEY_DEBUGGING 99 unsigned magic; 100 #define KEY_DEBUG_MAGIC 0x18273645u 101 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 102 #endif 103 104 /* the description string 105 * - this is used to match a key against search criteria 106 * - this should be a printable string 107 * - eg: for krb5 AFS, this might be "[email protected]" 108 */ 109 char *description; 110 111 /* type specific data 112 * - this is used by the keyring type to index the name 113 */ 114 union { 115 struct list_head link; 116 } type_data; 117 118 /* key data 119 * - this is used to hold the data actually used in cryptography or 120 * whatever 121 */ 122 union { 123 unsigned long value; 124 void *data; 125 struct keyring_list *subscriptions; 126 } payload; 127 }; 128 129 /*****************************************************************************/ 130 /* 131 * kernel managed key type definition 132 */ 133 struct key_type { 134 /* name of the type */ 135 const char *name; 136 137 /* default payload length for quota precalculation (optional) 138 * - this can be used instead of calling key_payload_reserve(), that 139 * function only needs to be called if the real datalen is different 140 */ 141 size_t def_datalen; 142 143 /* instantiate a key of this type 144 * - this method should call key_payload_reserve() to determine if the 145 * user's quota will hold the payload 146 */ 147 int (*instantiate)(struct key *key, const void *data, size_t datalen); 148 149 /* duplicate a key of this type (optional) 150 * - the source key will be locked against change 151 * - the new description will be attached 152 * - the quota will have been adjusted automatically from 153 * source->quotalen 154 */ 155 int (*duplicate)(struct key *key, const struct key *source); 156 157 /* update a key of this type (optional) 158 * - this method should call key_payload_reserve() to recalculate the 159 * quota consumption 160 * - the key must be locked against read when modifying 161 */ 162 int (*update)(struct key *key, const void *data, size_t datalen); 163 164 /* match a key against a description */ 165 int (*match)(const struct key *key, const void *desc); 166 167 /* clear the data from a key (optional) */ 168 void (*destroy)(struct key *key); 169 170 /* describe a key */ 171 void (*describe)(const struct key *key, struct seq_file *p); 172 173 /* read a key's data (optional) 174 * - permission checks will be done by the caller 175 * - the key's semaphore will be readlocked by the caller 176 * - should return the amount of data that could be read, no matter how 177 * much is copied into the buffer 178 * - shouldn't do the copy if the buffer is NULL 179 */ 180 long (*read)(const struct key *key, char __user *buffer, size_t buflen); 181 182 /* internal fields */ 183 struct list_head link; /* link in types list */ 184 }; 185 186 extern struct key_type key_type_keyring; 187 188 extern int register_key_type(struct key_type *ktype); 189 extern void unregister_key_type(struct key_type *ktype); 190 191 extern struct key *key_alloc(struct key_type *type, 192 const char *desc, 193 uid_t uid, gid_t gid, key_perm_t perm, 194 int not_in_quota); 195 extern int key_payload_reserve(struct key *key, size_t datalen); 196 extern int key_instantiate_and_link(struct key *key, 197 const void *data, 198 size_t datalen, 199 struct key *keyring); 200 extern int key_negate_and_link(struct key *key, 201 unsigned timeout, 202 struct key *keyring); 203 extern void key_revoke(struct key *key); 204 extern void key_put(struct key *key); 205 206 static inline struct key *key_get(struct key *key) 207 { 208 if (key) 209 atomic_inc(&key->usage); 210 return key; 211 } 212 213 extern struct key *request_key(struct key_type *type, 214 const char *description, 215 const char *callout_info); 216 217 extern int key_validate(struct key *key); 218 219 extern struct key *key_create_or_update(struct key *keyring, 220 const char *type, 221 const char *description, 222 const void *payload, 223 size_t plen, 224 int not_in_quota); 225 226 extern int key_update(struct key *key, 227 const void *payload, 228 size_t plen); 229 230 extern int key_link(struct key *keyring, 231 struct key *key); 232 233 extern int key_unlink(struct key *keyring, 234 struct key *key); 235 236 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, 237 int not_in_quota, struct key *dest); 238 239 extern int keyring_clear(struct key *keyring); 240 241 extern struct key *keyring_search(struct key *keyring, 242 struct key_type *type, 243 const char *description); 244 245 extern struct key *search_process_keyrings(struct key_type *type, 246 const char *description); 247 248 extern int keyring_add_key(struct key *keyring, 249 struct key *key); 250 251 extern struct key *key_lookup(key_serial_t id); 252 253 #define key_serial(key) ((key) ? (key)->serial : 0) 254 255 /* 256 * the userspace interface 257 */ 258 extern struct key root_user_keyring, root_session_keyring; 259 extern int alloc_uid_keyring(struct user_struct *user); 260 extern void switch_uid_keyring(struct user_struct *new_user); 261 extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk); 262 extern int copy_thread_group_keys(struct task_struct *tsk); 263 extern void exit_keys(struct task_struct *tsk); 264 extern void exit_thread_group_keys(struct signal_struct *tg); 265 extern int suid_keys(struct task_struct *tsk); 266 extern int exec_keys(struct task_struct *tsk); 267 extern void key_fsuid_changed(struct task_struct *tsk); 268 extern void key_fsgid_changed(struct task_struct *tsk); 269 extern void key_init(void); 270 271 #else /* CONFIG_KEYS */ 272 273 #define key_validate(k) 0 274 #define key_serial(k) 0 275 #define key_get(k) NULL 276 #define key_put(k) do { } while(0) 277 #define alloc_uid_keyring(u) 0 278 #define switch_uid_keyring(u) do { } while(0) 279 #define copy_keys(f,t) 0 280 #define copy_thread_group_keys(t) 0 281 #define exit_keys(t) do { } while(0) 282 #define exit_thread_group_keys(tg) do { } while(0) 283 #define suid_keys(t) do { } while(0) 284 #define exec_keys(t) do { } while(0) 285 #define key_fsuid_changed(t) do { } while(0) 286 #define key_fsgid_changed(t) do { } while(0) 287 #define key_init() do { } while(0) 288 289 #endif /* CONFIG_KEYS */ 290 #endif /* __KERNEL__ */ 291 #endif /* _LINUX_KEY_H */ 292