From fbcf68c280643bce8f6451cc84db2910755df5a8 Mon Sep 17 00:00:00 2001
From: jvoisin <julien.voisin@dustri.org>
Date: Sun, 9 Sep 2018 18:57:08 +0200
Subject: [PATCH] Lexicographical sort on xml attributes for office files
In XML, the order of the attributes shouldn't be meaningful,
however, MS Office sorts attributes for a given XML tag
differently than LibreOffice.
---
libmat2/office.py | 49 ++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 44 insertions(+), 5 deletions(-)
diff --git a/libmat2/office.py b/libmat2/office.py
index 50b776e..5c2c996 100644
--- a/libmat2/office.py
+++ b/libmat2/office.py
@@ -1,3 +1,4 @@
+import logging
import os
import re
import zipfile
@@ -12,16 +13,38 @@ assert Set
assert Pattern
def _parse_xml(full_path: str):
- """ This function parse XML, with namespace support. """
+ """ This function parses XML, with namespace support. """
+ cpt = 0
namespace_map = dict()
for _, (key, value) in ET.iterparse(full_path, ("start-ns", )):
+ # The ns[0-9]+ namespaces are reserved for interal usage, so
+ # we have to use an other nomenclature.
+ if re.match('^ns[0-9]+$', key):
+ key = 'mat%d' % cpt
+ cpt += 1
+
namespace_map[key] = value
ET.register_namespace(key, value)
return ET.parse(full_path), namespace_map
+def _sort_xml_attributes(full_path: str) -> bool:
+ """ Sort xml attributes lexicographically,
+ because it's possible to fingerprint producers (MS Office, Libreoffice, …)
+ since they are all using different orders.
+ """
+ tree = ET.parse(full_path)
+ root = tree.getroot()
+
+ for c in root:
+ c[:] = sorted(c, key=lambda child: (child.tag, child.get('desc')))
+
+ tree.write(full_path, xml_declaration=True)
+ return True
+
+
class MSOfficeParser(ArchiveBasedAbstractParser):
mimetypes = {
'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
@@ -49,7 +72,8 @@ class MSOfficeParser(ArchiveBasedAbstractParser):
"""
try:
tree, namespace = _parse_xml(full_path)
- except ET.ParseError:
+ except ET.ParseError as e:
+ logging.error("Unable to parse %s: %s", full_path, e)
return False
# Revisions are either deletions (`w:del`) or
@@ -83,6 +107,9 @@ class MSOfficeParser(ArchiveBasedAbstractParser):
return True
def _specific_cleanup(self, full_path: str) -> bool:
+ if os.stat(full_path).st_size == 0: # Don't process empty files
+ return True
+
if full_path.endswith('/word/document.xml'):
# this file contains the revisions
return self.__remove_revisions(full_path)
@@ -139,7 +166,8 @@ class LibreOfficeParser(ArchiveBasedAbstractParser):
def __remove_revisions(full_path: str) -> bool:
try:
tree, namespace = _parse_xml(full_path)
- except ET.ParseError:
+ except ET.ParseError as e:
+ logging.error("Unable to parse %s: %s", full_path, e)
return False
if 'office' not in namespace.keys(): # no revisions in the current file
@@ -154,8 +182,19 @@ class LibreOfficeParser(ArchiveBasedAbstractParser):
return True
def _specific_cleanup(self, full_path: str) -> bool:
- if os.path.basename(full_path) == 'content.xml':
- return self.__remove_revisions(full_path)
+ if os.stat(full_path).st_size == 0: # Don't process empty files
+ return True
+
+ if os.path.basename(full_path).endswith('.xml'):
+ if os.path.basename(full_path) == 'content.xml':
+ if self.__remove_revisions(full_path) is False:
+ return False
+
+ try:
+ _sort_xml_attributes(full_path)
+ except ET.ParseError as e:
+ logging.error("Unable to parse %s: %s", full_path, e)
+ return False
return True
def get_meta(self) -> Dict[str, str]:
--
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