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 key_ref_t key_ref, key_perm_t perm)
  46 {
  47         struct key *key = key_ref_to_ptr(key_ref);
  48         key_perm_t kperm;
  49
  50         if (is_key_possessed(key_ref))
  51                 kperm = key->perm >> 24;
  52         else if (key->uid == current->fsuid)
  53                 kperm = key->perm >> 16;
  54         else if (key->gid != -1 &&
  55                  key->perm & KEY_GRP_ALL &&
  56                  in_group_p(key->gid)
  57                  )
  58                 kperm = key->perm >> 8;
  59         else
  60                 kperm = key->perm;
  61
  62         kperm = kperm & perm & KEY_ALL;
  63
  64         return kperm == perm;
  65 }
  66
  67 /*
  68  * check to see whether permission is granted to use a key in at least one of
  69  * the desired ways
  70  */
  71 static inline int key_any_permission(const key_ref_t key_ref, key_perm_t perm)
  72 {
  73         struct key *key = key_ref_to_ptr(key_ref);
  74         key_perm_t kperm;
  75
  76         if (is_key_possessed(key_ref))
  77                 kperm = key->perm >> 24;
  78         else if (key->uid == current->fsuid)
  79                 kperm = key->perm >> 16;
  80         else if (key->gid != -1 &&
  81                  key->perm & KEY_GRP_ALL &&
  82                  in_group_p(key->gid)
  83                  )
  84                 kperm = key->perm >> 8;
  85         else
  86                 kperm = key->perm;
  87
  88         kperm = kperm & perm & KEY_ALL;
  89
  90         return kperm != 0;
  91 }
  92
  93 static inline int key_task_groups_search(struct task_struct *tsk, gid_t gid)
  94 {
  95         int ret;
  96
  97         task_lock(tsk);
  98         ret = groups_search(tsk->group_info, gid);
  99         task_unlock(tsk);
 100         return ret;
 101 }
 102
 103 static inline int key_task_permission(const key_ref_t key_ref,
 104                                       struct task_struct *context,
 105                                       key_perm_t perm)
 106 {
 107         struct key *key = key_ref_to_ptr(key_ref);
 108         key_perm_t kperm;
 109
 110         if (is_key_possessed(key_ref)) {
 111                 kperm = key->perm >> 24;
 112         }
 113         else if (key->uid == context->fsuid) {
 114                 kperm = key->perm >> 16;
 115         }
 116         else if (key->gid != -1 &&
 117                  key->perm & KEY_GRP_ALL && (
 118                          key->gid == context->fsgid ||
 119                          key_task_groups_search(context, key->gid)
 120                          )
 121                  ) {
 122                 kperm = key->perm >> 8;
 123         }
 124         else {
 125                 kperm = key->perm;
 126         }
 127
 128         kperm = kperm & perm & KEY_ALL;
 129
 130         return kperm == perm;
 131
 132 }
 133
 134 extern key_ref_t lookup_user_key(struct task_struct *context,
 135                                  key_serial_t id, int create, int partial,
 136                                  key_perm_t perm);
 137
 138 extern long join_session_keyring(const char *name);
 139
 140 extern struct key_type *key_type_lookup(const char *type);
 141 extern void key_type_put(struct key_type *ktype);
 142
 143 #define key_negative_timeout    60      /* default timeout on a negative key's existence */
 144
 145
 146 #endif /* _LINUX_KEY_UI_H */