From 4bb678e9d3892e8fceb4af5272cc45eb722f6baf Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Wed, 3 Mar 2010 11:37:18 +0100
Subject: [PATCH] utils: Add a PathJoin function
This will replace os.path.join since it is not safe for directory
traversal issues.
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
---
lib/utils.py | 30 ++++++++++++++++++++++++++++++
test/ganeti.utils_unittest.py | 19 ++++++++++++++++++-
2 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/lib/utils.py b/lib/utils.py
index 6877dc704..393f4f4f3 100644
--- a/lib/utils.py
+++ b/lib/utils.py
@@ -1936,6 +1936,36 @@ def IsNormAbsPath(path):
return os.path.normpath(path) == path and os.path.isabs(path)
+def PathJoin(*args):
+ """Safe-join a list of path components.
+
+ Requirements:
+ - the first argument must be an absolute path
+ - no component in the path must have backtracking (e.g. /../),
+ since we check for normalization at the end
+
+ @param args: the path components to be joined
+ @raise ValueError: for invalid paths
+
+ """
+ # ensure we're having at least one path passed in
+ assert args
+ # ensure the first component is an absolute and normalized path name
+ root = args[0]
+ if not IsNormAbsPath(root):
+ raise ValueError("Invalid parameter to PathJoin: '%s'" % str(args[0]))
+ result = os.path.join(*args)
+ # ensure that the whole path is normalized
+ if not IsNormAbsPath(result):
+ raise ValueError("Invalid parameters to PathJoin: '%s'" % str(args))
+ # check that we're still under the original prefix
+ prefix = os.path.commonprefix([root, result])
+ if prefix != root:
+ raise ValueError("Error: path joining resulted in different prefix"
+ " (%s != %s)" % (prefix, root))
+ return result
+
+
def TailFile(fname, lines=20):
"""Return the last lines from a file.
diff --git a/test/ganeti.utils_unittest.py b/test/ganeti.utils_unittest.py
index 4d19f8599..550bf2503 100755
--- a/test/ganeti.utils_unittest.py
+++ b/test/ganeti.utils_unittest.py
@@ -47,7 +47,7 @@ from ganeti.utils import IsProcessAlive, RunCmd, \
ShellQuote, ShellQuoteArgs, TcpPing, ListVisibleFiles, \
SetEtcHostsEntry, RemoveEtcHostsEntry, FirstFree, OwnIpAddress, \
TailFile, ForceDictType, SafeEncode, IsNormAbsPath, FormatTime, \
- UnescapeAndSplit, RunParts
+ UnescapeAndSplit, RunParts, PathJoin
from ganeti.errors import LockError, UnitParseError, GenericError, \
ProgrammerError
@@ -1260,5 +1260,22 @@ class TestUnescapeAndSplit(unittest.TestCase):
self.failUnlessEqual(UnescapeAndSplit(sep.join(a), sep=sep), b)
+class TestPathJoin(unittest.TestCase):
+ """Testing case for PathJoin"""
+
+ def testBasicItems(self):
+ mlist = ["/a", "b", "c"]
+ self.failUnlessEqual(PathJoin(*mlist), "/".join(mlist))
+
+ def testNonAbsPrefix(self):
+ self.failUnlessRaises(ValueError, PathJoin, "a", "b")
+
+ def testBackTrack(self):
+ self.failUnlessRaises(ValueError, PathJoin, "/a", "b/../c")
+
+ def testMultiAbs(self):
+ self.failUnlessRaises(ValueError, PathJoin, "/a", "/b")
+
+
if __name__ == '__main__':
testutils.GanetiTestProgram()
--
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