include/linux/key-ui.h

   1 /* key-ui.h: key userspace interface stuff
   2  *
   3  * Copyright (C) 2004 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 #ifndef _LINUX_KEY_UI_H
  13 #define _LINUX_KEY_UI_H
  14
  15 #include <linux/key.h>
  16
  17 /* the key tree */
  18 extern struct rb_root key_serial_tree;
  19 extern spinlock_t key_serial_lock;
  20
  21 /* required permissions */
  22 #define KEY_VIEW        0x01    /* require permission to view attributes */
  23 #define KEY_READ        0x02    /* require permission to read content */
  24 #define KEY_WRITE       0x04    /* require permission to update / modify */
  25 #define KEY_SEARCH      0x08    /* require permission to search (keyring) or find (key) */
  26 #define KEY_LINK        0x10    /* require permission to link */
  27 #define KEY_ALL         0x1f    /* all the above permissions */
  28
  29 /*
  30  * the keyring payload contains a list of the keys to which the keyring is
  31  * subscribed
  32  */
  33 struct keyring_list {
  34         struct rcu_head rcu;            /* RCU deletion hook */
  35         unsigned short  maxkeys;        /* max keys this list can hold */
  36         unsigned short  nkeys;          /* number of keys currently held */
  37         unsigned short  delkey;         /* key to be unlinked by RCU */
  38         struct key      *keys[0];
  39 };
  40
  41
  42 /*
  43  * check to see whether permission is granted to use a key in the desired way
  44  */
  45 static inline int key_permission(const struct key *key, key_perm_t perm)
  46 {
  47         key_perm_t kperm;
  48
  49         if (key->uid == current->fsuid)
  50                 kperm = key->perm >> 16;
  51         else if (key->gid != -1 &&
  52                  key->perm & KEY_GRP_ALL &&
  53                  in_group_p(key->gid)
  54                  )
  55                 kperm = key->perm >> 8;
  56         else
  57                 kperm = key->perm;
  58
  59         kperm = kperm & perm & KEY_ALL;
  60
  61         return kperm == perm;
  62 }
  63
  64 /*
  65  * check to see whether permission is granted to use a key in at least one of
  66  * the desired ways
  67  */
  68 static inline int key_any_permission(const struct key *key, key_perm_t perm)
  69 {
  70         key_perm_t kperm;
  71
  72         if (key->uid == current->fsuid)
  73                 kperm = key->perm >> 16;
  74         else if (key->gid != -1 &&
  75                  key->perm & KEY_GRP_ALL &&
  76                  in_group_p(key->gid)
  77                  )
  78                 kperm = key->perm >> 8;
  79         else
  80                 kperm = key->perm;
  81
  82         kperm = kperm & perm & KEY_ALL;
  83
  84         return kperm != 0;
  85 }
  86
  87 static inline int key_task_groups_search(struct task_struct *tsk, gid_t gid)
  88 {
  89         int ret;
  90
  91         task_lock(tsk);
  92         ret = groups_search(tsk->group_info, gid);
  93         task_unlock(tsk);
  94         return ret;
  95 }
  96
  97 static inline int key_task_permission(const struct key *key,
  98                                       struct task_struct *context,
  99                                       key_perm_t perm)
 100 {
 101         key_perm_t kperm;
 102
 103         if (key->uid == context->fsuid) {
 104                 kperm = key->perm >> 16;
 105         }
 106         else if (key->gid != -1 &&
 107                  key->perm & KEY_GRP_ALL && (
 108                          key->gid == context->fsgid ||
 109                          key_task_groups_search(context, key->gid)
 110                          )
 111                  ) {
 112                 kperm = key->perm >> 8;
 113         }
 114         else {
 115                 kperm = key->perm;
 116         }
 117
 118         kperm = kperm & perm & KEY_ALL;
 119
 120         return kperm == perm;
 121
 122 }
 123
 124 extern struct key *lookup_user_key(struct task_struct *context,
 125                                    key_serial_t id, int create, int partial,
 126                                    key_perm_t perm);
 127
 128 extern long join_session_keyring(const char *name);
 129
 130 extern struct key_type *key_type_lookup(const char *type);
 131 extern void key_type_put(struct key_type *ktype);
 132
 133 #define key_negative_timeout    60      /* default timeout on a negative key's existence */
 134
 135
 136 #endif /* _LINUX_KEY_UI_H */