*/
#include <linux/module.h>
+#include <linux/security.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
+/**
+ * key_task_permission - Check a key can be used
+ * @key_ref: The key to check
+ * @cred: The credentials to use
+ * @perm: The permissions to check for
+ *
+ * Check to see whether permission is granted to use a key in the desired way,
+ * but permit the security modules to override.
+ *
+ * The caller must hold either a ref on cred or must hold the RCU readlock or a
+ * spinlock.
*/
-int key_task_permission(const key_ref_t key_ref,
- struct task_struct *context,
+int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
key_perm_t perm)
{
struct key *key;
key = key_ref_to_ptr(key_ref);
/* use the second 8-bits of permissions for keys the caller owns */
- if (key->uid == context->fsuid) {
+ if (key->uid == cred->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) {
+ if (key->gid == cred->fsgid) {
kperm = key->perm >> 8;
goto use_these_perms;
}
- task_lock(context);
- ret = groups_search(context->group_info, key->gid);
- task_unlock(context);
-
+ ret = groups_search(cred->group_info, key->gid);
if (ret) {
kperm = key->perm >> 8;
goto use_these_perms;
kperm = key->perm;
use_these_perms:
+
/* use the top 8-bits of permissions for keys the caller possesses
* - possessor permissions are additive with other permissions
*/
kperm = kperm & perm & KEY_ALL;
- return kperm == perm;
+ if (kperm != perm)
+ return -EACCES;
+
+ /* let LSM be the final arbiter */
+ return security_key_permission(key_ref, cred, perm);
} /* end key_task_permission() */
EXPORT_SYMBOL(key_task_permission);
+
+/*****************************************************************************/
+/*
+ * validate a key
+ */
+int key_validate(struct key *key)
+{
+ struct timespec now;
+ int ret = 0;
+
+ if (key) {
+ /* check it's still accessible */
+ ret = -EKEYREVOKED;
+ if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
+ test_bit(KEY_FLAG_DEAD, &key->flags))
+ goto error;
+
+ /* check it hasn't expired */
+ ret = 0;
+ if (key->expiry) {
+ now = current_kernel_time();
+ if (now.tv_sec >= key->expiry)
+ ret = -EKEYEXPIRED;
+ }
+ }
+
+ error:
+ return ret;
+
+} /* end key_validate() */
+
+EXPORT_SYMBOL(key_validate);