git://bbs.cooldavid.org / net-next-2.6.git / blame
| Commit | Line | Data |
|---|---|---|
| 468ed2b0 DH |
1 | /* permission.c: key permission determination |
| 2 | * | |
| 3 | * Copyright (C) 2005 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 | #include <linux/module.h> | |
| 29db9190 | 13 | #include <linux/security.h> |
| 468ed2b0 DH |
14 | #include "internal.h" |
| 15 | ||
| 16 | /*****************************************************************************/ | |
| 17 | /* | |
| 18 | * check to see whether permission is granted to use a key in the desired way, | |
| 19 | * but permit the security modules to override | |
| 20 | */ | |
| 21 | int key_task_permission(const key_ref_t key_ref, | |
| 22 | struct task_struct *context, | |
| 23 | key_perm_t perm) | |
| 24 | { | |
| c69e8d9c | 25 | const struct cred *cred; |
| 468ed2b0 DH |
26 | struct key *key; |
| 27 | key_perm_t kperm; | |
| 28 | int ret; | |
| 29 | ||
| 30 | key = key_ref_to_ptr(key_ref); | |
| 31 | ||
| c69e8d9c DH |
32 | rcu_read_lock(); |
| 33 | cred = __task_cred(context); | |
| 34 | ||
| 468ed2b0 | 35 | /* use the second 8-bits of permissions for keys the caller owns */ |
| b6dff3ec | 36 | if (key->uid == cred->fsuid) { |
| 468ed2b0 DH |
37 | kperm = key->perm >> 16; |
| 38 | goto use_these_perms; | |
| 39 | } | |
| 40 | ||
| 41 | /* use the third 8-bits of permissions for keys the caller has a group | |
| 42 | * membership in common with */ | |
| 43 | if (key->gid != -1 && key->perm & KEY_GRP_ALL) { | |
| b6dff3ec | 44 | if (key->gid == cred->fsgid) { |
| 468ed2b0 DH |
45 | kperm = key->perm >> 8; |
| 46 | goto use_these_perms; | |
| 47 | } | |
| 48 | ||
| b6dff3ec | 49 | ret = groups_search(cred->group_info, key->gid); |
| 468ed2b0 DH |
50 | if (ret) { |
| 51 | kperm = key->perm >> 8; | |
| 52 | goto use_these_perms; | |
| 53 | } | |
| 54 | } | |
| 55 | ||
| 56 | /* otherwise use the least-significant 8-bits */ | |
| 57 | kperm = key->perm; | |
| 58 | ||
| 59 | use_these_perms: | |
| c69e8d9c DH |
60 | rcu_read_lock(); |
| 61 | ||
| 7ab501db DH |
62 | /* use the top 8-bits of permissions for keys the caller possesses |
| 63 | * - possessor permissions are additive with other permissions | |
| 64 | */ | |
| 65 | if (is_key_possessed(key_ref)) | |
| 66 | kperm |= key->perm >> 24; | |
| 67 | ||
| 468ed2b0 DH |
68 | kperm = kperm & perm & KEY_ALL; |
| 69 | ||
| 29db9190 DH |
70 | if (kperm != perm) |
| 71 | return -EACCES; | |
| 72 | ||
| 73 | /* let LSM be the final arbiter */ | |
| 74 | return security_key_permission(key_ref, context, perm); | |
| 468ed2b0 DH |
75 | |
| 76 | } /* end key_task_permission() */ | |
| 77 | ||
| 78 | EXPORT_SYMBOL(key_task_permission); | |
| b5f545c8 DH |
79 | |
| 80 | /*****************************************************************************/ | |
| 81 | /* | |
| 82 | * validate a key | |
| 83 | */ | |
| 84 | int key_validate(struct key *key) | |
| 85 | { | |
| 86 | struct timespec now; | |
| 87 | int ret = 0; | |
| 88 | ||
| 89 | if (key) { | |
| 90 | /* check it's still accessible */ | |
| 91 | ret = -EKEYREVOKED; | |
| 92 | if (test_bit(KEY_FLAG_REVOKED, &key->flags) || | |
| 93 | test_bit(KEY_FLAG_DEAD, &key->flags)) | |
| 94 | goto error; | |
| 95 | ||
| 96 | /* check it hasn't expired */ | |
| 97 | ret = 0; | |
| 98 | if (key->expiry) { | |
| 99 | now = current_kernel_time(); | |
| 100 | if (now.tv_sec >= key->expiry) | |
| 101 | ret = -EKEYEXPIRED; | |
| 102 | } | |
| 103 | } | |
| 104 | ||
| 105 | error: | |
| 106 | return ret; | |
| 107 | ||
| 108 | } /* end key_validate() */ | |
| 109 | ||
| 110 | EXPORT_SYMBOL(key_validate); |