diff options
Diffstat (limited to 'security')
| -rw-r--r-- | security/keys/Makefile | 1 | ||||
| -rw-r--r-- | security/keys/permission.c | 70 |
2 files changed, 71 insertions, 0 deletions
diff --git a/security/keys/Makefile b/security/keys/Makefile index c392d750b208..5145adfb6a05 100644 --- a/security/keys/Makefile +++ b/security/keys/Makefile @@ -6,6 +6,7 @@ obj-y := \ key.o \ keyring.o \ keyctl.o \ + permission.o \ process_keys.o \ request_key.o \ request_key_auth.o \ diff --git a/security/keys/permission.c b/security/keys/permission.c new file mode 100644 index 000000000000..1c3651670ce9 --- /dev/null +++ b/security/keys/permission.c @@ -0,0 +1,70 @@ +/* permission.c: key permission determination + * + * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/module.h> +#include "internal.h" + +/*****************************************************************************/ +/* + * check to see whether permission is granted to use a key in the desired way, + * but permit the security modules to override + */ +int key_task_permission(const key_ref_t key_ref, + struct task_struct *context, + key_perm_t perm) +{ + struct key *key; + key_perm_t kperm; + int ret; + + key = key_ref_to_ptr(key_ref); + + /* use the top 8-bits of permissions for keys the caller possesses */ + if (is_key_possessed(key_ref)) { + kperm = key->perm >> 24; + goto use_these_perms; + } + + /* use the second 8-bits of permissions for keys the caller owns */ + if (key->uid == context->fsuid) { + kperm = key->perm >> 16; + goto use_these_perms; + } + + /* use the third 8-bits of permissions for keys the caller has a group + * membership in common with */ + if (key->gid != -1 && key->perm & KEY_GRP_ALL) { + if (key->gid == context->fsgid) { + kperm = key->perm >> 8; + goto use_these_perms; + } + + task_lock(context); + ret = groups_search(context->group_info, key->gid); + task_unlock(context); + + if (ret) { + kperm = key->perm >> 8; + goto use_these_perms; + } + } + + /* otherwise use the least-significant 8-bits */ + kperm = key->perm; + +use_these_perms: + kperm = kperm & perm & KEY_ALL; + + return kperm == perm; + +} /* end key_task_permission() */ + +EXPORT_SYMBOL(key_task_permission); |