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 <linux/sysctl.h>
  23#include <asm/atomic.h>
  24
  25#ifdef __KERNEL__
  26
  27/* key handle serial number */
  28typedef int32_t key_serial_t;
  29
  30/* key handle permissions mask */
  31typedef uint32_t key_perm_t;
  32
  33struct 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
  73struct seq_file;
  74struct user_struct;
  75struct signal_struct;
  76
  77struct key_type;
  78struct key_owner;
  79struct keyring_list;
  80struct 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 */
  96typedef struct __key_reference_with_attributes *key_ref_t;
  97
  98static 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
 104static 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
 109static 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 */
 122struct 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 "afs@REDHAT.COM"
 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
 181extern 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
 193extern void key_revoke(struct key *key);
 194extern void key_put(struct key *key);
 195
 196static inline struct key *key_get(struct key *key)
 197{
 198        if (key)
 199                atomic_inc(&key->usage);
 200        return key;
 201}
 202
 203static inline void key_ref_put(key_ref_t key_ref)
 204{
 205        key_put(key_ref_to_ptr(key_ref));
 206}
 207
 208extern struct key *request_key(struct key_type *type,
 209                               const char *description,
 210                               const char *callout_info);
 211
 212extern 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
 218extern struct key *request_key_async(struct key_type *type,
 219                                     const char *description,
 220                                     const void *callout_info,
 221                                     size_t callout_len);
 222
 223extern 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
 229extern int wait_for_key_construction(struct key *key, bool intr);
 230
 231extern int key_validate(struct key *key);
 232
 233extern 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
 241extern int key_update(key_ref_t key,
 242                      const void *payload,
 243                      size_t plen);
 244
 245extern int key_link(struct key *keyring,
 246                    struct key *key);
 247
 248extern int key_unlink(struct key *keyring,
 249                      struct key *key);
 250
 251extern 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
 256extern int keyring_clear(struct key *keyring);
 257
 258extern key_ref_t keyring_search(key_ref_t keyring,
 259                                struct key_type *type,
 260                                const char *description);
 261
 262extern int keyring_add_key(struct key *keyring,
 263                           struct key *key);
 264
 265extern struct key *key_lookup(key_serial_t id);
 266
 267static inline key_serial_t key_serial(struct key *key)
 268{
 269        return key ? key->serial : 0;
 270}
 271
 272#ifdef CONFIG_SYSCTL
 273extern ctl_table key_sysctls[];
 274#endif
 275
 276/*
 277 * the userspace interface
 278 */
 279extern void switch_uid_keyring(struct user_struct *new_user);
 280extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
 281extern int copy_thread_group_keys(struct task_struct *tsk);
 282extern void exit_keys(struct task_struct *tsk);
 283extern void exit_thread_group_keys(struct signal_struct *tg);
 284extern int suid_keys(struct task_struct *tsk);
 285extern int exec_keys(struct task_struct *tsk);
 286extern void key_fsuid_changed(struct task_struct *tsk);
 287extern void key_fsgid_changed(struct task_struct *tsk);
 288extern 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_revoke(k)                   do { } while(0)
 303#define key_put(k)                      do { } while(0)
 304#define key_ref_put(k)                  do { } while(0)
 305#define make_key_ref(k, p)                      ({ NULL; })
 306#define key_ref_to_ptr(k)               ({ NULL; })
 307#define is_key_possessed(k)             0
 308#define switch_uid_keyring(u)           do { } while(0)
 309#define __install_session_keyring(t, k) ({ NULL; })
 310#define copy_keys(f,t)                  0
 311#define copy_thread_group_keys(t)       0
 312#define exit_keys(t)                    do { } while(0)
 313#define exit_thread_group_keys(tg)      do { } while(0)
 314#define suid_keys(t)                    do { } while(0)
 315#define exec_keys(t)                    do { } while(0)
 316#define key_fsuid_changed(t)            do { } while(0)
 317#define key_fsgid_changed(t)            do { } while(0)
 318#define key_init()                      do { } while(0)
 319
 320#endif /* CONFIG_KEYS */
 321#endif /* __KERNEL__ */
 322#endif /* _LINUX_KEY_H */
 323