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/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 <asm/atomic.h> 24 25 #ifdef __KERNEL__ 26 27 /* key handle serial number */ 28 typedef int32_t key_serial_t; 29 30 /* key handle permissions mask */ 31 typedef uint32_t key_perm_t; 32 33 struct key; 34 35 #ifdef CONFIG_KEYS 36 37 #undef KEY_DEBUGGING 38 39 #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */ 40 #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */ 41 #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */ 42 #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */ 43 #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */ 44 #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */ 45 #define KEY_POS_ALL 0x3f000000 46 47 #define KEY_USR_VIEW 0x00010000 /* user permissions... */ 48 #define KEY_USR_READ 0x00020000 49 #define KEY_USR_WRITE 0x00040000 50 #define KEY_USR_SEARCH 0x00080000 51 #define KEY_USR_LINK 0x00100000 52 #define KEY_USR_SETATTR 0x00200000 53 #define KEY_USR_ALL 0x003f0000 54 55 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ 56 #define KEY_GRP_READ 0x00000200 57 #define KEY_GRP_WRITE 0x00000400 58 #define KEY_GRP_SEARCH 0x00000800 59 #define KEY_GRP_LINK 0x00001000 60 #define KEY_GRP_SETATTR 0x00002000 61 #define KEY_GRP_ALL 0x00003f00 62 63 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ 64 #define KEY_OTH_READ 0x00000002 65 #define KEY_OTH_WRITE 0x00000004 66 #define KEY_OTH_SEARCH 0x00000008 67 #define KEY_OTH_LINK 0x00000010 68 #define KEY_OTH_SETATTR 0x00000020 69 #define KEY_OTH_ALL 0x0000003f 70 71 #define KEY_PERM_UNDEF 0xffffffff 72 73 struct seq_file; 74 struct user_struct; 75 struct signal_struct; 76 77 struct key_type; 78 struct key_owner; 79 struct keyring_list; 80 struct keyring_name; 81 82 /*****************************************************************************/ 83 /* 84 * key reference with possession attribute handling 85 * 86 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 87 * defined. This is because we abuse the bottom bit of the reference to carry a 88 * flag to indicate whether the calling process possesses that key in one of 89 * its keyrings. 90 * 91 * the key_ref_t has been made a separate type so that the compiler can reject 92 * attempts to dereference it without proper conversion. 93 * 94 * the three functions are used to assemble and disassemble references 95 */ 96 typedef struct __key_reference_with_attributes *key_ref_t; 97 98 static inline key_ref_t make_key_ref(const struct key *key, 99 unsigned long possession) 100 { 101 return (key_ref_t) ((unsigned long) key | possession); 102 } 103 104 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 105 { 106 return (struct key *) ((unsigned long) key_ref & ~1UL); 107 } 108 109 static inline unsigned long is_key_possessed(const key_ref_t key_ref) 110 { 111 return (unsigned long) key_ref & 1UL; 112 } 113 114 /*****************************************************************************/ 115 /* 116 * authentication token / access credential / keyring 117 * - types of key include: 118 * - keyrings 119 * - disk encryption IDs 120 * - Kerberos TGTs and tickets 121 */ 122 struct key { 123 atomic_t usage; /* number of references */ 124 key_serial_t serial; /* key serial number */ 125 struct rb_node serial_node; 126 struct key_type *type; /* type of key */ 127 struct rw_semaphore sem; /* change vs change sem */ 128 struct key_user *user; /* owner of this key */ 129 void *security; /* security data for this key */ 130 time_t expiry; /* time at which key expires (or 0) */ 131 uid_t uid; 132 gid_t gid; 133 key_perm_t perm; /* access permissions */ 134 unsigned short quotalen; /* length added to quota */ 135 unsigned short datalen; /* payload data length 136 * - may not match RCU dereferenced payload 137 * - payload should contain own length 138 */ 139 140 #ifdef KEY_DEBUGGING 141 unsigned magic; 142 #define KEY_DEBUG_MAGIC 0x18273645u 143 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 144 #endif 145 146 unsigned long flags; /* status flags (change with bitops) */ 147 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 148 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 149 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 150 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 151 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 152 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 153 154 /* the description string 155 * - this is used to match a key against search criteria 156 * - this should be a printable string 157 * - eg: for krb5 AFS, this might be "[email protected]" 158 */ 159 char *description; 160 161 /* type specific data 162 * - this is used by the keyring type to index the name 163 */ 164 union { 165 struct list_head link; 166 unsigned long x[2]; 167 void *p[2]; 168 } type_data; 169 170 /* key data 171 * - this is used to hold the data actually used in cryptography or 172 * whatever 173 */ 174 union { 175 unsigned long value; 176 void *data; 177 struct keyring_list *subscriptions; 178 } payload; 179 }; 180 181 extern struct key *key_alloc(struct key_type *type, 182 const char *desc, 183 uid_t uid, gid_t gid, 184 struct task_struct *ctx, 185 key_perm_t perm, 186 unsigned long flags); 187 188 189 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 190 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 191 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 192 193 extern void key_revoke(struct key *key); 194 extern void key_put(struct key *key); 195 196 static inline struct key *key_get(struct key *key) 197 { 198 if (key) 199 atomic_inc(&key->usage); 200 return key; 201 } 202 203 static inline void key_ref_put(key_ref_t key_ref) 204 { 205 key_put(key_ref_to_ptr(key_ref)); 206 } 207 208 extern struct key *request_key(struct key_type *type, 209 const char *description, 210 const char *callout_info); 211 212 extern struct key *request_key_with_auxdata(struct key_type *type, 213 const char *description, 214 const void *callout_info, 215 size_t callout_len, 216 void *aux); 217 218 extern struct key *request_key_async(struct key_type *type, 219 const char *description, 220 const void *callout_info, 221 size_t callout_len); 222 223 extern struct key *request_key_async_with_auxdata(struct key_type *type, 224 const char *description, 225 const void *callout_info, 226 size_t callout_len, 227 void *aux); 228 229 extern int wait_for_key_construction(struct key *key, bool intr); 230 231 extern int key_validate(struct key *key); 232 233 extern key_ref_t key_create_or_update(key_ref_t keyring, 234 const char *type, 235 const char *description, 236 const void *payload, 237 size_t plen, 238 key_perm_t perm, 239 unsigned long flags); 240 241 extern int key_update(key_ref_t key, 242 const void *payload, 243 size_t plen); 244 245 extern int key_link(struct key *keyring, 246 struct key *key); 247 248 extern int key_unlink(struct key *keyring, 249 struct key *key); 250 251 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, 252 struct task_struct *ctx, 253 unsigned long flags, 254 struct key *dest); 255 256 extern int keyring_clear(struct key *keyring); 257 258 extern key_ref_t keyring_search(key_ref_t keyring, 259 struct key_type *type, 260 const char *description); 261 262 extern int keyring_add_key(struct key *keyring, 263 struct key *key); 264 265 extern struct key *key_lookup(key_serial_t id); 266 267 static inline key_serial_t key_serial(struct key *key) 268 { 269 return key ? key->serial : 0; 270 } 271 272 #ifdef CONFIG_SYSCTL 273 extern ctl_table key_sysctls[]; 274 #endif 275 276 /* 277 * the userspace interface 278 */ 279 extern void switch_uid_keyring(struct user_struct *new_user); 280 extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk); 281 extern int copy_thread_group_keys(struct task_struct *tsk); 282 extern void exit_keys(struct task_struct *tsk); 283 extern void exit_thread_group_keys(struct signal_struct *tg); 284 extern int suid_keys(struct task_struct *tsk); 285 extern int exec_keys(struct task_struct *tsk); 286 extern void key_fsuid_changed(struct task_struct *tsk); 287 extern void key_fsgid_changed(struct task_struct *tsk); 288 extern void key_init(void); 289 290 #define __install_session_keyring(tsk, keyring) \ 291 ({ \ 292 struct key *old_session = tsk->signal->session_keyring; \ 293 tsk->signal->session_keyring = keyring; \ 294 old_session; \ 295 }) 296 297 #else /* CONFIG_KEYS */ 298 299 #define key_validate(k) 0 300 #define key_serial(k) 0 301 #define key_get(k) ({ NULL; }) 302 #define key_put(k) do { } while(0) 303 #define key_ref_put(k) do { } while(0) 304 #define make_key_ref(k, p) ({ NULL; }) 305 #define key_ref_to_ptr(k) ({ NULL; }) 306 #define is_key_possessed(k) 0 307 #define switch_uid_keyring(u) do { } while(0) 308 #define __install_session_keyring(t, k) ({ NULL; }) 309 #define copy_keys(f,t) 0 310 #define copy_thread_group_keys(t) 0 311 #define exit_keys(t) do { } while(0) 312 #define exit_thread_group_keys(tg) do { } while(0) 313 #define suid_keys(t) do { } while(0) 314 #define exec_keys(t) do { } while(0) 315 #define key_fsuid_changed(t) do { } while(0) 316 #define key_fsgid_changed(t) do { } while(0) 317 #define key_init() do { } while(0) 318 319 #endif /* CONFIG_KEYS */ 320 #endif /* __KERNEL__ */ 321 #endif /* _LINUX_KEY_H */ 322