_mountinfo: skip mount entires with non-absolute root

1 files changed, 14 insertions, 2 deletions

diff --git a/lbup/_mountinfo.py b/lbup/_mountinfo.py
index 110eb6c..e687e96 100644
--- a/lbup/_mountinfo.py
+++ b/lbup/_mountinfo.py
@@ -15,6 +15,12 @@ def _oct_unescape(b):
 
     return b
 
+class NotAbsRoot(Exception):
+    # This exception is raised for mount entries whose root is not
+    # a valid absolute path (this happens e.g. for persistent namespaces bound
+    # to a file). Such entries are skipped from MountInfo
+    pass
+
 class _MountEntry:
     "mount ID, bytes"
     mount_id      = None
@@ -56,7 +62,10 @@ class _MountEntry:
             raise ValueError('Invalid device number', devnum)
         self.devnum = (major << 8) + minor
 
-        self.root        = AbsPath(_oct_unescape(root))
+        root = _oct_unescape(root)
+        if len(root) < 1 or not root.startswith(b'/'):
+            raise NotAbsRoot()
+        self.root        = AbsPath(root)
         self.mount_point = AbsPath(_oct_unescape(mount_point))
         self.mount_opts  = mount_opts
 
@@ -94,7 +103,10 @@ class MountInfo:
     def __init__(self, data):
         self.entries = []
         for line in data.splitlines():
-            self.entries.append(_MountEntry(line))
+            try:
+                self.entries.append(_MountEntry(line))
+            except NotAbsRoot:
+                pass
 
     def __str__(self):
         return '%s(%d entries)' % (self.__class__.__name__, len(self.entries))