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