From 35c5a0b279b99f30430f4a8e5092c7b2f1234316 Mon Sep 17 00:00:00 2001
From: Ryan Harper <ryan.harper@canonical.com>
Date: Thu, 19 Nov 2015 13:55:58 -0600
Subject: [PATCH] Protect mountpoint from relative paths and duplicate pathsep

Use os.path.realpath() to clean up any path manipulations

Signed-off-by: Ryan Harper <ryan.harper@canonical.com>
---
 subiquity/models/filesystem.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/subiquity/models/filesystem.py b/subiquity/models/filesystem.py
index 0cac77e1..373f2b74 100644
--- a/subiquity/models/filesystem.py
+++ b/subiquity/models/filesystem.py
@@ -16,6 +16,7 @@
 import json
 import logging
 import re
+from os.path import realpath
 
 from .blockdev import Blockdev, Raiddev, Bcachedev, sort_actions
 import math
@@ -470,6 +471,9 @@ class FilesystemModel(ModelPolicy):
         if not mountpoint.startswith('/'):
             raise ValueError('Does not start with /')
 
+        # remove redundent // and ..
+        mountpoint = realpath(mountpoint)
+
         # /usr/include/linux/limits.h:PATH_MAX
         if len(mountpoint) > 4095:
             raise ValueError('Path exceeds PATH_MAX')