From 03dd4cb26d967f9588437b0fc9cc0e8353322bb7 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Fri, 25 Mar 2016 03:53:42 -0300
Subject: Linux-libre 4.5-gnu

---
 security/keys/keyctl.c | 49 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 41 insertions(+), 8 deletions(-)

(limited to 'security/keys/keyctl.c')

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 1c3872aee..ed73c6c1c 100644
--- 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 +380,12 @@ long keyctl_revoke_key(key_serial_t id)
 		}
 	}
 
-	key_revoke(key_ref_to_ptr(key_ref));
+	key = key_ref_to_ptr(key_ref);
 	ret = 0;
+	if (test_bit(KEY_FLAG_KEEP, &key->flags))
+		ret = -EPERM;
+	else
+		key_revoke(key);
 
 	key_ref_put(key_ref);
 error:
@@ -392,11 +399,14 @@ 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 +430,12 @@ long keyctl_invalidate_key(key_serial_t id)
 	}
 
 invalidate:
-	key_invalidate(key_ref_to_ptr(key_ref));
+	key = key_ref_to_ptr(key_ref);
 	ret = 0;
+	if (test_bit(KEY_FLAG_KEEP, &key->flags))
+		ret = -EPERM;
+	else
+		key_invalidate(key);
 error_put:
 	key_ref_put(key_ref);
 error:
@@ -433,12 +447,13 @@ 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 +475,11 @@ 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 +530,14 @@ 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 +552,13 @@ 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 +1317,8 @@ 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 +1350,13 @@ long keyctl_set_timeout(key_serial_t id, unsigned timeout)
 
 okay:
 	key = key_ref_to_ptr(key_ref);
-	key_set_timeout(key, timeout);
+	ret = 0;
+	if (test_bit(KEY_FLAG_KEEP, &key->flags))
+		ret = -EPERM;
+	else
+		key_set_timeout(key, timeout);
 	key_put(key);
 
-	ret = 0;
 error:
 	return ret;
 }
-- 
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