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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: #include <linux/assoc_array.h> 26: 27: #ifdef __KERNEL__ 28: #include <linux/uidgid.h> 29: 30: /* key handle serial number */ 31: typedef int32_t key_serial_t; 32: 33: /* key handle permissions mask */ 34: typedef uint32_t key_perm_t; 35: 36: struct key; 37: 38: #ifdef CONFIG_KEYS 39: 40: #undef KEY_DEBUGGING 41: 42: #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */ 43: #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */ 44: #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */ 45: #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */ 46: #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */ 47: #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */ 48: #define KEY_POS_ALL 0x3f000000 49: 50: #define KEY_USR_VIEW 0x00010000 /* user permissions... */ 51: #define KEY_USR_READ 0x00020000 52: #define KEY_USR_WRITE 0x00040000 53: #define KEY_USR_SEARCH 0x00080000 54: #define KEY_USR_LINK 0x00100000 55: #define KEY_USR_SETATTR 0x00200000 56: #define KEY_USR_ALL 0x003f0000 57: 58: #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ 59: #define KEY_GRP_READ 0x00000200 60: #define KEY_GRP_WRITE 0x00000400 61: #define KEY_GRP_SEARCH 0x00000800 62: #define KEY_GRP_LINK 0x00001000 63: #define KEY_GRP_SETATTR 0x00002000 64: #define KEY_GRP_ALL 0x00003f00 65: 66: #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ 67: #define KEY_OTH_READ 0x00000002 68: #define KEY_OTH_WRITE 0x00000004 69: #define KEY_OTH_SEARCH 0x00000008 70: #define KEY_OTH_LINK 0x00000010 71: #define KEY_OTH_SETATTR 0x00000020 72: #define KEY_OTH_ALL 0x0000003f 73: 74: #define KEY_PERM_UNDEF 0xffffffff 75: 76: struct seq_file; 77: struct user_struct; 78: struct signal_struct; 79: struct cred; 80: 81: struct key_type; 82: struct key_owner; 83: struct keyring_list; 84: struct keyring_name; 85: 86: struct keyring_index_key { 87: struct key_type *type; 88: const char *description; 89: size_t desc_len; 90: }; 91: 92: /*****************************************************************************/ 93: /* 94: * key reference with possession attribute handling 95: * 96: * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually 97: * defined. This is because we abuse the bottom bit of the reference to carry a 98: * flag to indicate whether the calling process possesses that key in one of 99: * its keyrings. 100: * 101: * the key_ref_t has been made a separate type so that the compiler can reject 102: * attempts to dereference it without proper conversion. 103: * 104: * the three functions are used to assemble and disassemble references 105: */ 106: typedef struct __key_reference_with_attributes *key_ref_t; 107: 108: static inline key_ref_t make_key_ref(const struct key *key, 109: bool possession) 110: { 111: return (key_ref_t) ((unsigned long) key | possession); 112: } 113: 114: static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) 115: { 116: return (struct key *) ((unsigned long) key_ref & ~1UL); 117: } 118: 119: static inline bool is_key_possessed(const key_ref_t key_ref) 120: { 121: return (unsigned long) key_ref & 1UL; 122: } 123: 124: /*****************************************************************************/ 125: /* 126: * authentication token / access credential / keyring 127: * - types of key include: 128: * - keyrings 129: * - disk encryption IDs 130: * - Kerberos TGTs and tickets 131: */ 132: struct key { 133: atomic_t usage; /* number of references */ 134: key_serial_t serial; /* key serial number */ 135: union { 136: struct list_head graveyard_link; 137: struct rb_node serial_node; 138: }; 139: struct rw_semaphore sem; /* change vs change sem */ 140: struct key_user *user; /* owner of this key */ 141: void *security; /* security data for this key */ 142: union { 143: time_t expiry; /* time at which key expires (or 0) */ 144: time_t revoked_at; /* time at which key was revoked */ 145: }; 146: time_t last_used_at; /* last time used for LRU keyring discard */ 147: kuid_t uid; 148: kgid_t gid; 149: key_perm_t perm; /* access permissions */ 150: unsigned short quotalen; /* length added to quota */ 151: unsigned short datalen; /* payload data length 152: * - may not match RCU dereferenced payload 153: * - payload should contain own length 154: */ 155: 156: #ifdef KEY_DEBUGGING 157: unsigned magic; 158: #define KEY_DEBUG_MAGIC 0x18273645u 159: #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu 160: #endif 161: 162: unsigned long flags; /* status flags (change with bitops) */ 163: #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ 164: #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ 165: #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ 166: #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ 167: #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ 168: #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ 169: #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ 170: #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ 171: #define KEY_FLAG_TRUSTED 8 /* set if key is trusted */ 172: #define KEY_FLAG_TRUSTED_ONLY 9 /* set if keyring only accepts links to trusted keys */ 173: 174: /* the key type and key description string 175: * - the desc is used to match a key against search criteria 176: * - it should be a printable string 177: * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" 178: */ 179: union { 180: struct keyring_index_key index_key; 181: struct { 182: struct key_type *type; /* type of key */ 183: char *description; 184: }; 185: }; 186: 187: /* type specific data 188: * - this is used by the keyring type to index the name 189: */ 190: union { 191: struct list_head link; 192: unsigned long x[2]; 193: void *p[2]; 194: int reject_error; 195: } type_data; 196: 197: /* key data 198: * - this is used to hold the data actually used in cryptography or 199: * whatever 200: */ 201: union { 202: union { 203: unsigned long value; 204: void __rcu *rcudata; 205: void *data; 206: void *data2[2]; 207: } payload; 208: struct assoc_array keys; 209: }; 210: }; 211: 212: extern struct key *key_alloc(struct key_type *type, 213: const char *desc, 214: kuid_t uid, kgid_t gid, 215: const struct cred *cred, 216: key_perm_t perm, 217: unsigned long flags); 218: 219: 220: #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ 221: #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ 222: #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ 223: #define KEY_ALLOC_TRUSTED 0x0004 /* Key should be flagged as trusted */ 224: 225: extern void key_revoke(struct key *key); 226: extern void key_invalidate(struct key *key); 227: extern void key_put(struct key *key); 228: 229: static inline struct key *__key_get(struct key *key) 230: { 231: atomic_inc(&key->usage); 232: return key; 233: } 234: 235: static inline struct key *key_get(struct key *key) 236: { 237: return key ? __key_get(key) : key; 238: } 239: 240: static inline void key_ref_put(key_ref_t key_ref) 241: { 242: key_put(key_ref_to_ptr(key_ref)); 243: } 244: 245: extern struct key *request_key(struct key_type *type, 246: const char *description, 247: const char *callout_info); 248: 249: extern struct key *request_key_with_auxdata(struct key_type *type, 250: const char *description, 251: const void *callout_info, 252: size_t callout_len, 253: void *aux); 254: 255: extern struct key *request_key_async(struct key_type *type, 256: const char *description, 257: const void *callout_info, 258: size_t callout_len); 259: 260: extern struct key *request_key_async_with_auxdata(struct key_type *type, 261: const char *description, 262: const void *callout_info, 263: size_t callout_len, 264: void *aux); 265: 266: extern int wait_for_key_construction(struct key *key, bool intr); 267: 268: extern int key_validate(const struct key *key); 269: 270: extern key_ref_t key_create_or_update(key_ref_t keyring, 271: const char *type, 272: const char *description, 273: const void *payload, 274: size_t plen, 275: key_perm_t perm, 276: unsigned long flags); 277: 278: extern int key_update(key_ref_t key, 279: const void *payload, 280: size_t plen); 281: 282: extern int key_link(struct key *keyring, 283: struct key *key); 284: 285: extern int key_unlink(struct key *keyring, 286: struct key *key); 287: 288: extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, 289: const struct cred *cred, 290: key_perm_t perm, 291: unsigned long flags, 292: struct key *dest); 293: 294: extern int keyring_clear(struct key *keyring); 295: 296: extern key_ref_t keyring_search(key_ref_t keyring, 297: struct key_type *type, 298: const char *description); 299: 300: extern int keyring_add_key(struct key *keyring, 301: struct key *key); 302: 303: extern struct key *key_lookup(key_serial_t id); 304: 305: static inline key_serial_t key_serial(const struct key *key) 306: { 307: return key ? key->serial : 0; 308: } 309: 310: extern void key_set_timeout(struct key *, unsigned); 311: 312: /** 313: * key_is_instantiated - Determine if a key has been positively instantiated 314: * @key: The key to check. 315: * 316: * Return true if the specified key has been positively instantiated, false 317: * otherwise. 318: */ 319: static inline bool key_is_instantiated(const struct key *key) 320: { 321: return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && 322: !test_bit(KEY_FLAG_NEGATIVE, &key->flags); 323: } 324: 325: #define rcu_dereference_key(KEY) \ 326: (rcu_dereference_protected((KEY)->payload.rcudata, \ 327: rwsem_is_locked(&((struct key *)(KEY))->sem))) 328: 329: #define rcu_assign_keypointer(KEY, PAYLOAD) \ 330: do { \ 331: rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \ 332: } while (0) 333: 334: #ifdef CONFIG_SYSCTL 335: extern ctl_table key_sysctls[]; 336: #endif 337: /* 338: * the userspace interface 339: */ 340: extern int install_thread_keyring_to_cred(struct cred *cred); 341: extern void key_fsuid_changed(struct task_struct *tsk); 342: extern void key_fsgid_changed(struct task_struct *tsk); 343: extern void key_init(void); 344: 345: #else /* CONFIG_KEYS */ 346: 347: #define key_validate(k) 0 348: #define key_serial(k) 0 349: #define key_get(k) ({ NULL; }) 350: #define key_revoke(k) do { } while(0) 351: #define key_invalidate(k) do { } while(0) 352: #define key_put(k) do { } while(0) 353: #define key_ref_put(k) do { } while(0) 354: #define make_key_ref(k, p) NULL 355: #define key_ref_to_ptr(k) NULL 356: #define is_key_possessed(k) 0 357: #define key_fsuid_changed(t) do { } while(0) 358: #define key_fsgid_changed(t) do { } while(0) 359: #define key_init() do { } while(0) 360: 361: #endif /* CONFIG_KEYS */ 362: #endif /* __KERNEL__ */ 363: #endif /* _LINUX_KEY_H */ 364: