LXR linux/include/linux/key.h

   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 <asm/atomic.h>
  23
  24#ifdef __KERNEL__
  25
  26/* key handle serial number */
  27typedef int32_t key_serial_t;
  28
  29/* key handle permissions mask */
  30typedef uint32_t key_perm_t;
  31
  32struct key;
  33
  34#ifdef CONFIG_KEYS
  35
  36#undef KEY_DEBUGGING
  37
  38#define KEY_POS_VIEW    0x01000000      /* possessor can view a key's attributes */
  39#define KEY_POS_READ    0x02000000      /* possessor can read key payload / view keyring */
  40#define KEY_POS_WRITE   0x04000000      /* possessor can update key payload / add link to keyring */
  41#define KEY_POS_SEARCH  0x08000000      /* possessor can find a key in search / search a keyring */
  42#define KEY_POS_LINK    0x10000000      /* possessor can create a link to a key/keyring */
  43#define KEY_POS_SETATTR 0x20000000      /* possessor can set key attributes */
  44#define KEY_POS_ALL     0x3f000000
  45
  46#define KEY_USR_VIEW    0x00010000      /* user permissions... */
  47#define KEY_USR_READ    0x00020000
  48#define KEY_USR_WRITE   0x00040000
  49#define KEY_USR_SEARCH  0x00080000
  50#define KEY_USR_LINK    0x00100000
  51#define KEY_USR_SETATTR 0x00200000
  52#define KEY_USR_ALL     0x003f0000
  53
  54#define KEY_GRP_VIEW    0x00000100      /* group permissions... */
  55#define KEY_GRP_READ    0x00000200
  56#define KEY_GRP_WRITE   0x00000400
  57#define KEY_GRP_SEARCH  0x00000800
  58#define KEY_GRP_LINK    0x00001000
  59#define KEY_GRP_SETATTR 0x00002000
  60#define KEY_GRP_ALL     0x00003f00
  61
  62#define KEY_OTH_VIEW    0x00000001      /* third party permissions... */
  63#define KEY_OTH_READ    0x00000002
  64#define KEY_OTH_WRITE   0x00000004
  65#define KEY_OTH_SEARCH  0x00000008
  66#define KEY_OTH_LINK    0x00000010
  67#define KEY_OTH_SETATTR 0x00000020
  68#define KEY_OTH_ALL     0x0000003f
  69
  70struct seq_file;
  71struct user_struct;
  72struct signal_struct;
  73
  74struct key_type;
  75struct key_owner;
  76struct keyring_list;
  77struct keyring_name;
  78
  79/*****************************************************************************/
  80/*
  81 * key reference with possession attribute handling
  82 *
  83 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
  84 * defined. This is because we abuse the bottom bit of the reference to carry a
  85 * flag to indicate whether the calling process possesses that key in one of
  86 * its keyrings.
  87 *
  88 * the key_ref_t has been made a separate type so that the compiler can reject
  89 * attempts to dereference it without proper conversion.
  90 *
  91 * the three functions are used to assemble and disassemble references
  92 */
  93typedef struct __key_reference_with_attributes *key_ref_t;
  94
  95static inline key_ref_t make_key_ref(const struct key *key,
  96                                     unsigned long possession)
  97{
  98        return (key_ref_t) ((unsigned long) key | possession);
  99}
 100
 101static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
 102{
 103        return (struct key *) ((unsigned long) key_ref & ~1UL);
 104}
 105
 106static inline unsigned long is_key_possessed(const key_ref_t key_ref)
 107{
 108        return (unsigned long) key_ref & 1UL;
 109}
 110
 111/*****************************************************************************/
 112/*
 113 * authentication token / access credential / keyring
 114 * - types of key include:
 115 *   - keyrings
 116 *   - disk encryption IDs
 117 *   - Kerberos TGTs and tickets
 118 */
 119struct key {
 120        atomic_t                usage;          /* number of references */
 121        key_serial_t            serial;         /* key serial number */
 122        struct rb_node          serial_node;
 123        struct key_type         *type;          /* type of key */
 124        struct rw_semaphore     sem;            /* change vs change sem */
 125        struct key_user         *user;          /* owner of this key */
 126        void                    *security;      /* security data for this key */
 127        time_t                  expiry;         /* time at which key expires (or 0) */
 128        uid_t                   uid;
 129        gid_t                   gid;
 130        key_perm_t              perm;           /* access permissions */
 131        unsigned short          quotalen;       /* length added to quota */
 132        unsigned short          datalen;        /* payload data length
 133                                                 * - may not match RCU dereferenced payload
 134                                                 * - payload should contain own length
 135                                                 */
 136
 137#ifdef KEY_DEBUGGING
 138        unsigned                magic;
 139#define KEY_DEBUG_MAGIC         0x18273645u
 140#define KEY_DEBUG_MAGIC_X       0xf8e9dacbu
 141#endif
 142
 143        unsigned long           flags;          /* status flags (change with bitops) */
 144#define KEY_FLAG_INSTANTIATED   0       /* set if key has been instantiated */
 145#define KEY_FLAG_DEAD           1       /* set if key type has been deleted */
 146#define KEY_FLAG_REVOKED        2       /* set if key had been revoked */
 147#define KEY_FLAG_IN_QUOTA       3       /* set if key consumes quota */
 148#define KEY_FLAG_USER_CONSTRUCT 4       /* set if key is being constructed in userspace */
 149#define KEY_FLAG_NEGATIVE       5       /* set if key is negative */
 150
 151        /* the description string
 152         * - this is used to match a key against search criteria
 153         * - this should be a printable string
 154         * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
 155         */
 156        char                    *description;
 157
 158        /* type specific data
 159         * - this is used by the keyring type to index the name
 160         */
 161        union {
 162                struct list_head        link;
 163                unsigned long           x[2];
 164                void                    *p[2];
 165        } type_data;
 166
 167        /* key data
 168         * - this is used to hold the data actually used in cryptography or
 169         *   whatever
 170         */
 171        union {
 172                unsigned long           value;
 173                void                    *data;
 174                struct keyring_list     *subscriptions;
 175        } payload;
 176};
 177
 178extern struct key *key_alloc(struct key_type *type,
 179                             const char *desc,
 180                             uid_t uid, gid_t gid,
 181                             struct task_struct *ctx,
 182                             key_perm_t perm,
 183                             unsigned long flags);
 184
 185
 186#define KEY_ALLOC_IN_QUOTA      0x0000  /* add to quota, reject if would overrun */
 187#define KEY_ALLOC_QUOTA_OVERRUN 0x0001  /* add to quota, permit even if overrun */
 188#define KEY_ALLOC_NOT_IN_QUOTA  0x0002  /* not in quota */
 189
 190extern void key_revoke(struct key *key);
 191extern void key_put(struct key *key);
 192
 193static inline struct key *key_get(struct key *key)
 194{
 195        if (key)
 196                atomic_inc(&key->usage);
 197        return key;
 198}
 199
 200static inline void key_ref_put(key_ref_t key_ref)
 201{
 202        key_put(key_ref_to_ptr(key_ref));
 203}
 204
 205extern struct key *request_key(struct key_type *type,
 206                               const char *description,
 207                               const char *callout_info);
 208
 209extern struct key *request_key_with_auxdata(struct key_type *type,
 210                                            const char *description,
 211                                            const char *callout_info,
 212                                            void *aux);
 213
 214extern struct key *request_key_async(struct key_type *type,
 215                                     const char *description,
 216                                     const char *callout_info);
 217
 218extern struct key *request_key_async_with_auxdata(struct key_type *type,
 219                                                  const char *description,
 220                                                  const char *callout_info,
 221                                                  void *aux);
 222
 223extern int wait_for_key_construction(struct key *key, bool intr);
 224
 225extern int key_validate(struct key *key);
 226
 227extern key_ref_t key_create_or_update(key_ref_t keyring,
 228                                      const char *type,
 229                                      const char *description,
 230                                      const void *payload,
 231                                      size_t plen,
 232                                      unsigned long flags);
 233
 234extern int key_update(key_ref_t key,
 235                      const void *payload,
 236                      size_t plen);
 237
 238extern int key_link(struct key *keyring,
 239                    struct key *key);
 240
 241extern int key_unlink(struct key *keyring,
 242                      struct key *key);
 243
 244extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
 245                                 struct task_struct *ctx,
 246                                 unsigned long flags,
 247                                 struct key *dest);
 248
 249extern int keyring_clear(struct key *keyring);
 250
 251extern key_ref_t keyring_search(key_ref_t keyring,
 252                                struct key_type *type,
 253                                const char *description);
 254
 255extern int keyring_add_key(struct key *keyring,
 256                           struct key *key);
 257
 258extern struct key *key_lookup(key_serial_t id);
 259
 260#define key_serial(key) ((key) ? (key)->serial : 0)
 261
 262/*
 263 * the userspace interface
 264 */
 265extern struct key root_user_keyring, root_session_keyring;
 266extern int alloc_uid_keyring(struct user_struct *user,
 267                             struct task_struct *ctx);
 268extern void switch_uid_keyring(struct user_struct *new_user);
 269extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
 270extern int copy_thread_group_keys(struct task_struct *tsk);
 271extern void exit_keys(struct task_struct *tsk);
 272extern void exit_thread_group_keys(struct signal_struct *tg);
 273extern int suid_keys(struct task_struct *tsk);
 274extern int exec_keys(struct task_struct *tsk);
 275extern void key_fsuid_changed(struct task_struct *tsk);
 276extern void key_fsgid_changed(struct task_struct *tsk);
 277extern void key_init(void);
 278
 279#define __install_session_keyring(tsk, keyring)                 \
 280({                                                              \
 281        struct key *old_session = tsk->signal->session_keyring; \
 282        tsk->signal->session_keyring = keyring;                 \
 283        old_session;                                            \
 284})
 285
 286#else /* CONFIG_KEYS */
 287
 288#define key_validate(k)                 0
 289#define key_serial(k)                   0
 290#define key_get(k)                      ({ NULL; })
 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 alloc_uid_keyring(u,c)          0
 297#define switch_uid_keyring(u)           do { } while(0)
 298#define __install_session_keyring(t, k) ({ NULL; })
 299#define copy_keys(f,t)                  0
 300#define copy_thread_group_keys(t)       0
 301#define exit_keys(t)                    do { } while(0)
 302#define exit_thread_group_keys(tg)      do { } while(0)
 303#define suid_keys(t)                    do { } while(0)
 304#define exec_keys(t)                    do { } while(0)
 305#define key_fsuid_changed(t)            do { } while(0)
 306#define key_fsgid_changed(t)            do { } while(0)
 307#define key_init()                      do { } while(0)
 308
 309/* Initial keyrings */
 310extern struct key root_user_keyring;
 311extern struct key root_session_keyring;
 312
 313#endif /* CONFIG_KEYS */
 314#endif /* __KERNEL__ */
 315#endif /* _LINUX_KEY_H */
 316