KEYS: prevent keys from being removed from specified keyrings

[linux-2.6-microblaze.git] / security / keys / keyctl.c

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index fb111ea..e83ec6b 100644 (file)
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -358,11 +358,14 @@ error:
  * and any links to the key will be automatically garbage collected after a
  * certain amount of time (/proc/sys/kernel/keys/gc_delay).
  *
+ * Keys with KEY_FLAG_KEEP set should not be revoked.
+ *
  * If successful, 0 is returned.
  */
 long keyctl_revoke_key(key_serial_t id)
 {
        key_ref_t key_ref;
+       struct key *key;
        long ret;
 
        key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
@@ -377,8 +380,13 @@ long keyctl_revoke_key(key_serial_t id)
                }
        }
 
-       key_revoke(key_ref_to_ptr(key_ref));
-       ret = 0;
+       key = key_ref_to_ptr(key_ref);
+       if (test_bit(KEY_FLAG_KEEP, &key->flags))
+               return -EPERM;
+       else {
+               key_revoke(key);
+               ret = 0;
+       }
 
        key_ref_put(key_ref);
 error:
@@ -392,11 +400,14 @@ error:
  * The key and any links to the key will be automatically garbage collected
  * immediately.
  *
+ * Keys with KEY_FLAG_KEEP set should not be invalidated.
+ *
  * If successful, 0 is returned.
  */
 long keyctl_invalidate_key(key_serial_t id)
 {
        key_ref_t key_ref;
+       struct key *key;
        long ret;
 
        kenter("%d", id);
@@ -420,8 +431,13 @@ long keyctl_invalidate_key(key_serial_t id)
        }
 
 invalidate:
-       key_invalidate(key_ref_to_ptr(key_ref));
-       ret = 0;
+       key = key_ref_to_ptr(key_ref);
+       if (test_bit(KEY_FLAG_KEEP, &key->flags))
+               ret = -EPERM;
+       else {
+               key_invalidate(key);
+               ret = 0;
+       }
 error_put:
        key_ref_put(key_ref);
 error:
@@ -433,12 +449,13 @@ error:
  * Clear the specified keyring, creating an empty process keyring if one of the
  * special keyring IDs is used.
  *
- * The keyring must grant the caller Write permission for this to work.  If
- * successful, 0 will be returned.
+ * The keyring must grant the caller Write permission and not have
+ * KEY_FLAG_KEEP set for this to work.  If successful, 0 will be returned.
  */
 long keyctl_keyring_clear(key_serial_t ringid)
 {
        key_ref_t keyring_ref;
+       struct key *keyring;
        long ret;
 
        keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
@@ -460,7 +477,11 @@ long keyctl_keyring_clear(key_serial_t ringid)
        }
 
 clear:
-       ret = keyring_clear(key_ref_to_ptr(keyring_ref));
+       keyring = key_ref_to_ptr(keyring_ref);
+       if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
+               ret = -EPERM;
+       else
+               ret = keyring_clear(keyring);
 error_put:
        key_ref_put(keyring_ref);
 error:
@@ -511,11 +532,14 @@ error:
  * itself need not grant the caller anything.  If the last link to a key is
  * removed then that key will be scheduled for destruction.
  *
+ * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
+ *
  * If successful, 0 will be returned.
  */
 long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
 {
        key_ref_t keyring_ref, key_ref;
+       struct key *keyring, *key;
        long ret;
 
        keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
@@ -530,7 +554,13 @@ long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
                goto error2;
        }
 
-       ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
+       keyring = key_ref_to_ptr(keyring_ref);
+       key = key_ref_to_ptr(key_ref);
+       if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
+           test_bit(KEY_FLAG_KEEP, &key->flags))
+               ret = -EPERM;
+       else
+               ret = key_unlink(keyring, key);
 
        key_ref_put(key_ref);
 error2:
@@ -1289,6 +1319,8 @@ error:
  * the current time.  The key and any links to the key will be automatically
  * garbage collected after the timeout expires.
  *
+ * Keys with KEY_FLAG_KEEP set should not be timed out.
+ *
  * If successful, 0 is returned.
  */
 long keyctl_set_timeout(key_serial_t id, unsigned timeout)
@@ -1320,10 +1352,14 @@ long keyctl_set_timeout(key_serial_t id, unsigned timeout)
 
 okay:
        key = key_ref_to_ptr(key_ref);
-       key_set_timeout(key, timeout);
+       if (test_bit(KEY_FLAG_KEEP, &key->flags))
+               ret = -EPERM;
+       else {
+               key_set_timeout(key, timeout);
+               ret = 0;
+       }
        key_put(key);
 
-       ret = 0;
 error:
        return ret;
 }