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mat2/libmat2/office.py
jvoisin 09e748fa4c Refactor how offices files are handled
- xml files are no longer considered harmless
- Factorization of the `remove_all` method for office files
- Explicit whitelist are used
- Blacklist are used to skip files completely
  - Non-blacklisted files are _still cleaned_
  - Unsupported files are still triggering an error
2018-06-21 23:02:41 +02:00

171 lines
6.1 KiB
Python

import os
import re
import shutil
import tempfile
import datetime
import zipfile
from typing import Dict, Set, Pattern
from . import abstract, parser_factory
class ArchiveBasedAbstractParser(abstract.AbstractParser):
files_to_keep : Set[str] = set()
files_to_omit : Set[Pattern] = set()
def _clean_zipinfo(self, zipinfo: zipfile.ZipInfo) -> zipfile.ZipInfo:
zipinfo.create_system = 3 # Linux
zipinfo.comment = b''
zipinfo.date_time = (1980, 1, 1, 0, 0, 0)
return zipinfo
def _get_zipinfo_meta(self, zipinfo: zipfile.ZipInfo) -> Dict[str, str]:
metadata = {}
if zipinfo.create_system == 3:
#metadata['create_system'] = 'Linux'
pass
elif zipinfo.create_system == 2:
metadata['create_system'] = 'Windows'
else:
metadata['create_system'] = 'Weird'
if zipinfo.comment:
metadata['comment'] = zipinfo.comment # type: ignore
if zipinfo.date_time != (1980, 1, 1, 0, 0, 0):
metadata['date_time'] = str(datetime.datetime(*zipinfo.date_time))
return metadata
def _clean_internal_file(self, item: zipfile.ZipInfo, temp_folder: str,
zin: zipfile.ZipFile, zout: zipfile.ZipFile) -> bool:
zin.extract(member=item, path=temp_folder)
full_path = os.path.join(temp_folder, item.filename)
tmp_parser, mtype = parser_factory.get_parser(full_path) # type: ignore
if not tmp_parser:
zout.close()
os.remove(self.output_filename)
print("%s's format (%s) isn't supported" % (item.filename, mtype))
return False
tmp_parser.remove_all()
zinfo = zipfile.ZipInfo(item.filename) # type: ignore
clean_zinfo = self._clean_zipinfo(zinfo)
with open(tmp_parser.output_filename, 'rb') as f:
zout.writestr(clean_zinfo, f.read())
return True
def remove_all(self) -> bool:
zin = zipfile.ZipFile(self.filename, 'r')
zout = zipfile.ZipFile(self.output_filename, 'w')
temp_folder = tempfile.mkdtemp()
for item in zin.infolist():
if item.filename[-1] == '/': # `is_dir` is added in Python3.6
continue # don't keep empty folders
elif item.filename in self.files_to_keep:
item = self._clean_zipinfo(item)
zout.writestr(item, zin.read(item))
continue
elif any(map(lambda r: r.search(item.filename), self.files_to_omit)):
continue
elif not self._clean_internal_file(item, temp_folder, zin, zout):
return False
shutil.rmtree(temp_folder)
zout.close()
zin.close()
return True
class MSOfficeParser(ArchiveBasedAbstractParser):
mimetypes = {
'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
'application/vnd.openxmlformats-officedocument.presentationml.presentation'
}
files_to_keep = {
'[Content_Types].xml',
'_rels/.rels',
'word/_rels/document.xml.rels',
'word/document.xml',
'word/fontTable.xml',
'word/settings.xml',
'word/styles.xml',
}
files_to_omit = set(map(re.compile, { # type: ignore
'^docProps/',
}))
def get_meta(self) -> Dict[str, str]:
"""
Yes, I know that parsing xml with regexp ain't pretty,
be my guest and fix it if you want.
"""
metadata = {}
zipin = zipfile.ZipFile(self.filename)
for item in zipin.infolist():
if item.filename.startswith('docProps/') and item.filename.endswith('.xml'):
content = zipin.read(item).decode('utf-8')
try:
results = re.findall(r"<(.+)>(.+)</\1>", content, re.I|re.M)
for (key, value) in results:
metadata[key] = value
except TypeError: # We didn't manage to parse the xml file
pass
if not metadata: # better safe than sorry
metadata[item] = 'harmful content'
for key, value in self._get_zipinfo_meta(item).items():
metadata[key] = value
zipin.close()
return metadata
class LibreOfficeParser(ArchiveBasedAbstractParser):
mimetypes = {
'application/vnd.oasis.opendocument.text',
'application/vnd.oasis.opendocument.spreadsheet',
'application/vnd.oasis.opendocument.presentation',
'application/vnd.oasis.opendocument.graphics',
'application/vnd.oasis.opendocument.chart',
'application/vnd.oasis.opendocument.formula',
'application/vnd.oasis.opendocument.image',
}
files_to_keep = {
'META-INF/manifest.xml',
'content.xml',
'manifest.rdf',
'mimetype',
'settings.xml',
'styles.xml',
}
files_to_omit = set(map(re.compile, { # type: ignore
'^meta\.xml$',
'^Configurations2/',
}))
def get_meta(self) -> Dict[str, str]:
"""
Yes, I know that parsing xml with regexp ain't pretty,
be my guest and fix it if you want.
"""
metadata = {}
zipin = zipfile.ZipFile(self.filename)
for item in zipin.infolist():
if item.filename == 'meta.xml':
content = zipin.read(item).decode('utf-8')
try:
results = re.findall(r"<((?:meta|dc|cp).+?)>(.+)</\1>", content, re.I|re.M)
for (key, value) in results:
metadata[key] = value
except TypeError: # We didn't manage to parse the xml file
pass
if not metadata: # better safe than sorry
metadata[item] = 'harmful content'
for key, value in self._get_zipinfo_meta(item).items():
metadata[key] = value
zipin.close()
return metadata