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;
  76struct cred;
  77
  78struct key_type;
  79struct key_owner;
  80struct keyring_list;
  81struct 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 */
  97typedef struct __key_reference_with_attributes *key_ref_t;
  98
  99static 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
 105static 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
 110static 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 */
 123struct 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 "afs@REDHAT.COM"
 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
 182extern 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
 194extern void key_revoke(struct key *key);
 195extern void key_put(struct key *key);
 196
 197static inline struct key *key_get(struct key *key)
 198{
 199        if (key)
 200                atomic_inc(&key->usage);
 201        return key;
 202}
 203
 204static inline void key_ref_put(key_ref_t key_ref)
 205{
 206        key_put(key_ref_to_ptr(key_ref));
 207}
 208
 209extern struct key *request_key(struct key_type *type,
 210                               const char *description,
 211                               const char *callout_info);
 212
 213extern 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
 219extern struct key *request_key_async(struct key_type *type,
 220                                     const char *description,
 221                                     const void *callout_info,
 222                                     size_t callout_len);
 223
 224extern 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
 230extern int wait_for_key_construction(struct key *key, bool intr);
 231
 232extern int key_validate(struct key *key);
 233
 234extern 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
 242extern int key_update(key_ref_t key,
 243                      const void *payload,
 244                      size_t plen);
 245
 246extern int key_link(struct key *keyring,
 247                    struct key *key);
 248
 249extern int key_unlink(struct key *keyring,
 250                      struct key *key);
 251
 252extern 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
 257extern int keyring_clear(struct key *keyring);
 258
 259extern key_ref_t keyring_search(key_ref_t keyring,
 260                                struct key_type *type,
 261                                const char *description);
 262
 263extern int keyring_add_key(struct key *keyring,
 264                           struct key *key);
 265
 266extern struct key *key_lookup(key_serial_t id);
 267
 268static inline key_serial_t key_serial(struct key *key)
 269{
 270        return key ? key->serial : 0;
 271}
 272
 273#ifdef CONFIG_SYSCTL
 274extern ctl_table key_sysctls[];
 275#endif
 276
 277/*
 278 * the userspace interface
 279 */
 280extern int install_thread_keyring_to_cred(struct cred *cred);
 281extern void key_fsuid_changed(struct task_struct *tsk);
 282extern void key_fsgid_changed(struct task_struct *tsk);
 283extern 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