ubifs: free the encrypted symlink target

ubifs_symlink() forgot to free the kmalloc()'ed buffer holding the
encrypted symlink target, creating a memory leak.  Fix it.

(UBIFS could actually encrypt directly into ui->data, removing the
temporary buffer, but that is left for the patch that switches to use
the symlink helper functions.)

Fixes: ca7f85be8d ("ubifs: Add support for encrypted symlinks")
Cc: <stable@vger.kernel.org> # v4.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ubifs/dir.c

@@ -1216,10 +1216,8 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 		ostr.len = disk_link.len;
 
 		err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
-		if (err) {
-			kfree(sd);
+		if (err)
 			goto out_inode;
-		}
 
 		sd->len = cpu_to_le16(ostr.len);
 		disk_link.name = (char *)sd;
@@ -1251,11 +1249,10 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 		goto out_cancel;
 	mutex_unlock(&dir_ui->ui_mutex);
 
-	ubifs_release_budget(c, &req);
 	insert_inode_hash(inode);
 	d_instantiate(dentry, inode);
-	fscrypt_free_filename(&nm);
-	return 0;
+	err = 0;
+	goto out_fname;
 
 out_cancel:
 	dir->i_size -= sz_change;
@@ -1268,6 +1265,7 @@ out_fname:
 	fscrypt_free_filename(&nm);
 out_budg:
 	ubifs_release_budget(c, &req);
+	kfree(sd);
 	return err;
 }