1 files changed, 17 insertions, 14 deletions

diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 1cca09aa43f8..78dd2ff306bd 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -79,10 +79,9 @@ void fscrypt_put_master_key(struct fscrypt_master_key *mk)
 	call_rcu(&mk->mk_rcu_head, fscrypt_free_master_key);
 }
 
-void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk)
+void fscrypt_put_master_key_activeref(struct super_block *sb,
+				      struct fscrypt_master_key *mk)
 {
-	struct super_block *sb = mk->mk_sb;
-	struct fscrypt_keyring *keyring = sb->s_master_keys;
 	size_t i;
 
 	if (!refcount_dec_and_test(&mk->mk_active_refs))
@@ -93,9 +92,9 @@ void fscrypt_put_master_key_activeref(struct fscrypt_master_key *mk)
 	 * destroying any subkeys embedded in it.
 	 */
 
-	spin_lock(&keyring->lock);
+	spin_lock(&sb->s_master_keys->lock);
 	hlist_del_rcu(&mk->mk_node);
-	spin_unlock(&keyring->lock);
+	spin_unlock(&sb->s_master_keys->lock);
 
 	/*
 	 * ->mk_active_refs == 0 implies that ->mk_secret is not present and
@@ -205,14 +204,19 @@ static int allocate_filesystem_keyring(struct super_block *sb)
 }
 
 /*
- * This is called at unmount time to release all encryption keys that have been
- * added to the filesystem, along with the keyring that contains them.
+ * Release all encryption keys that have been added to the filesystem, along
+ * with the keyring that contains them.
+ *
+ * This is called at unmount time.  The filesystem's underlying block device(s)
+ * are still available at this time; this is important because after user file
+ * accesses have been allowed, this function may need to evict keys from the
+ * keyslots of an inline crypto engine, which requires the block device(s).
  *
- * Note that besides clearing and freeing memory, this might need to evict keys
- * from the keyslots of an inline crypto engine.  Therefore, this must be called
- * while the filesystem's underlying block device(s) are still available.
+ * This is also called when the super_block is being freed.  This is needed to
+ * avoid a memory leak if mounting fails after the "test_dummy_encryption"
+ * option was processed, as in that case the unmount-time call isn't made.
  */
-void fscrypt_sb_delete(struct super_block *sb)
+void fscrypt_destroy_keyring(struct super_block *sb)
 {
 	struct fscrypt_keyring *keyring = sb->s_master_keys;
 	size_t i;
@@ -238,7 +242,7 @@ void fscrypt_sb_delete(struct super_block *sb)
 			WARN_ON(refcount_read(&mk->mk_struct_refs) != 1);
 			WARN_ON(!is_master_key_secret_present(&mk->mk_secret));
 			wipe_master_key_secret(&mk->mk_secret);
-			fscrypt_put_master_key_activeref(mk);
+			fscrypt_put_master_key_activeref(sb, mk);
 		}
 	}
 	kfree_sensitive(keyring);
@@ -419,7 +423,6 @@ static int add_new_master_key(struct super_block *sb,
 	if (!mk)
 		return -ENOMEM;
 
-	mk->mk_sb = sb;
 	init_rwsem(&mk->mk_sem);
 	refcount_set(&mk->mk_struct_refs, 1);
 	mk->mk_spec = *mk_spec;
@@ -1063,7 +1066,7 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
 	err = -ENOKEY;
 	if (is_master_key_secret_present(&mk->mk_secret)) {
 		wipe_master_key_secret(&mk->mk_secret);
-		fscrypt_put_master_key_activeref(mk);
+		fscrypt_put_master_key_activeref(sb, mk);
 		err = 0;
 	}
 	inodes_remain = refcount_read(&mk->mk_active_refs) > 0;