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 struct cred; 77 78 struct key_type; 79 struct key_owner; 80 struct keyring_list; 81 struct keyring_name; 82 83 /*****************************************************************************/ 84 /* 85 * key reference with possession attribute handling 86 * 87 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 88 * defined. This is because we abuse the bottom bit of the reference to carry a 89 * flag to indicate whether the calling process possesses that key in one of 90 * its keyrings. 91 * 92 * the key_ref_t has been made a separate type so that the compiler can reject 93 * attempts to dereference it without proper conversion. 94 * 95 * the three functions are used to assemble and disassemble references 96 */ 97 typedef struct __key_reference_with_attributes *key_ref_t; 98 99 static inline key_ref_t make_key_ref(const struct key *key, 100 unsigned long possession) 101 { 102 return (key_ref_t) ((unsigned long) key | possession); 103 } 104 105 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 106 { 107 return (struct key *) ((unsigned long) key_ref & ~1UL); 108 } 109 110 static inline unsigned long is_key_possessed(const key_ref_t key_ref) 111 { 112 return (unsigned long) key_ref & 1UL; 113 } 114 115 /*****************************************************************************/ 116 /* 117 * authentication token / access credential / keyring 118 * - types of key include: 119 * - keyrings 120 * - disk encryption IDs 121 * - Kerberos TGTs and tickets 122 */ 123 struct key { 124 atomic_t usage; /* number of references */ 125 key_serial_t serial; /* key serial number */ 126 struct rb_node serial_node; 127 struct key_type *type; /* type of key */ 128 struct rw_semaphore sem; /* change vs change sem */ 129 struct key_user *user; /* owner of this key */ 130 void *security; /* security data for this key */ 131 time_t expiry; /* time at which key expires (or 0) */ 132 uid_t uid; 133 gid_t gid; 134 key_perm_t perm; /* access permissions */ 135 unsigned short quotalen; /* length added to quota */ 136 unsigned short datalen; /* payload data length 137 * - may not match RCU dereferenced payload 138 * - payload should contain own length 139 */ 140 141 #ifdef KEY_DEBUGGING 142 unsigned magic; 143 #define KEY_DEBUG_MAGIC 0x18273645u 144 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 145 #endif 146 147 unsigned long flags; /* status flags (change with bitops) */ 148 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 149 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 150 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 151 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 152 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 153 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 154 155 /* the description string 156 * - this is used to match a key against search criteria 157 * - this should be a printable string 158 * - eg: for krb5 AFS, this might be "[email protected]" 159 */ 160 char *description; 161 162 /* type specific data 163 * - this is used by the keyring type to index the name 164 */ 165 union { 166 struct list_head link; 167 unsigned long x[2]; 168 void *p[2]; 169 } type_data; 170 171 /* key data 172 * - this is used to hold the data actually used in cryptography or 173 * whatever 174 */ 175 union { 176 unsigned long value; 177 void *data; 178 struct keyring_list *subscriptions; 179 } payload; 180 }; 181 182 extern struct key *key_alloc(struct key_type *type, 183 const char *desc, 184 uid_t uid, gid_t gid, 185 const struct cred *cred, 186 key_perm_t perm, 187 unsigned long flags); 188 189 190 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 191 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 192 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 193 194 extern void key_revoke(struct key *key); 195 extern void key_put(struct key *key); 196 197 static inline struct key *key_get(struct key *key) 198 { 199 if (key) 200 atomic_inc(&key->usage); 201 return key; 202 } 203 204 static inline void key_ref_put(key_ref_t key_ref) 205 { 206 key_put(key_ref_to_ptr(key_ref)); 207 } 208 209 extern struct key *request_key(struct key_type *type, 210 const char *description, 211 const char *callout_info); 212 213 extern struct key *request_key_with_auxdata(struct key_type *type, 214 const char *description, 215 const void *callout_info, 216 size_t callout_len, 217 void *aux); 218 219 extern struct key *request_key_async(struct key_type *type, 220 const char *description, 221 const void *callout_info, 222 size_t callout_len); 223 224 extern struct key *request_key_async_with_auxdata(struct key_type *type, 225 const char *description, 226 const void *callout_info, 227 size_t callout_len, 228 void *aux); 229 230 extern int wait_for_key_construction(struct key *key, bool intr); 231 232 extern int key_validate(struct key *key); 233 234 extern key_ref_t key_create_or_update(key_ref_t keyring, 235 const char *type, 236 const char *description, 237 const void *payload, 238 size_t plen, 239 key_perm_t perm, 240 unsigned long flags); 241 242 extern int key_update(key_ref_t key, 243 const void *payload, 244 size_t plen); 245 246 extern int key_link(struct key *keyring, 247 struct key *key); 248 249 extern int key_unlink(struct key *keyring, 250 struct key *key); 251 252 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, 253 const struct cred *cred, 254 unsigned long flags, 255 struct key *dest); 256 257 extern int keyring_clear(struct key *keyring); 258 259 extern key_ref_t keyring_search(key_ref_t keyring, 260 struct key_type *type, 261 const char *description); 262 263 extern int keyring_add_key(struct key *keyring, 264 struct key *key); 265 266 extern struct key *key_lookup(key_serial_t id); 267 268 static inline key_serial_t key_serial(struct key *key) 269 { 270 return key ? key->serial : 0; 271 } 272 273 #ifdef CONFIG_SYSCTL 274 extern ctl_table key_sysctls[]; 275 #endif 276 277 /* 278 * the userspace interface 279 */ 280 extern int install_thread_keyring_to_cred(struct cred *cred); 281 extern void key_fsuid_changed(struct task_struct *tsk); 282 extern void key_fsgid_changed(struct task_struct *tsk); 283 extern void key_init(void); 284 285 #else /* CONFIG_KEYS */ 286 287 #define key_validate(k) 0 288 #define key_serial(k) 0 289 #define key_get(k) ({ NULL; }) 290 #define key_revoke(k) do { } while(0) 291 #define key_put(k) do { } while(0) 292 #define key_ref_put(k) do { } while(0) 293 #define make_key_ref(k, p) NULL 294 #define key_ref_to_ptr(k) NULL 295 #define is_key_possessed(k) 0 296 #define key_fsuid_changed(t) do { } while(0) 297 #define key_fsgid_changed(t) do { } while(0) 298 #define key_init() do { } while(0) 299 300 #endif /* CONFIG_KEYS */ 301 #endif /* __KERNEL__ */ 302 #endif /* _LINUX_KEY_H */ 303