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
This commit is contained in:
jvoisin
parent
a89dae054a
commit
09e748fa4c
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@ -4,7 +4,7 @@ from . import abstract
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class HarmlessParser(abstract.AbstractParser):
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""" This is the parser for filetypes that do not contain metadata. """
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mimetypes = {'application/xml', 'text/plain', 'text/xml', 'application/rdf+xml'}
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mimetypes = {'text/plain', }
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def __init__(self, filename: str) -> None:
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super().__init__(filename)
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@ -4,17 +4,16 @@ import shutil
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import tempfile
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import datetime
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import zipfile
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from typing import Dict, Set
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from typing import Dict, Set, Pattern
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from . import abstract, parser_factory
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assert Set # make pyflakes happy
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class ArchiveBasedAbstractParser(abstract.AbstractParser):
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whitelist = set() # type: Set[str]
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files_to_keep : Set[str] = set()
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files_to_omit : Set[Pattern] = set()
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def _clean_zipinfo(self, zipinfo: zipfile.ZipInfo) -> zipfile.ZipInfo:
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zipinfo.compress_type = zipfile.ZIP_DEFLATED
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zipinfo.create_system = 3 # Linux
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zipinfo.comment = b''
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zipinfo.date_time = (1980, 1, 1, 0, 0, 0)
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@ -34,33 +33,51 @@ class ArchiveBasedAbstractParser(abstract.AbstractParser):
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metadata['comment'] = zipinfo.comment # type: ignore
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if zipinfo.date_time != (1980, 1, 1, 0, 0, 0):
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metadata['date_time'] =str(datetime.datetime(*zipinfo.date_time))
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metadata['date_time'] = str(datetime.datetime(*zipinfo.date_time))
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return metadata
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def _clean_internal_file(self, item: zipfile.ZipInfo, temp_folder: str,
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zin: zipfile.ZipFile, zout: zipfile.ZipFile) -> bool:
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output = ''
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zin.extract(member=item, path=temp_folder)
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if item.filename not in self.whitelist:
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full_path = os.path.join(temp_folder, item.filename)
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tmp_parser, mtype = parser_factory.get_parser(full_path) # type: ignore
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if not tmp_parser:
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zout.close()
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os.remove(self.output_filename)
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print("%s's format (%s) isn't supported" % (item.filename, mtype))
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return False
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tmp_parser.remove_all()
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output = tmp_parser.output_filename
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else:
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output = os.path.join(temp_folder, item.filename)
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full_path = os.path.join(temp_folder, item.filename)
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tmp_parser, mtype = parser_factory.get_parser(full_path) # type: ignore
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if not tmp_parser:
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zout.close()
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os.remove(self.output_filename)
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print("%s's format (%s) isn't supported" % (item.filename, mtype))
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return False
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tmp_parser.remove_all()
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zinfo = zipfile.ZipInfo(item.filename) # type: ignore
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clean_zinfo = self._clean_zipinfo(zinfo)
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with open(output, 'rb') as f:
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with open(tmp_parser.output_filename, 'rb') as f:
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zout.writestr(clean_zinfo, f.read())
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return True
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def remove_all(self) -> bool:
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zin = zipfile.ZipFile(self.filename, 'r')
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zout = zipfile.ZipFile(self.output_filename, 'w')
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temp_folder = tempfile.mkdtemp()
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for item in zin.infolist():
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if item.filename[-1] == '/': # `is_dir` is added in Python3.6
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continue # don't keep empty folders
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elif item.filename in self.files_to_keep:
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item = self._clean_zipinfo(item)
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zout.writestr(item, zin.read(item))
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continue
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elif any(map(lambda r: r.search(item.filename), self.files_to_omit)):
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continue
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elif not self._clean_internal_file(item, temp_folder, zin, zout):
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return False
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shutil.rmtree(temp_folder)
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zout.close()
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zin.close()
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return True
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class MSOfficeParser(ArchiveBasedAbstractParser):
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mimetypes = {
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@ -68,9 +85,20 @@ class MSOfficeParser(ArchiveBasedAbstractParser):
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'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
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'application/vnd.openxmlformats-officedocument.presentationml.presentation'
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}
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files_to_keep = {'_rels/.rels', 'word/_rels/document.xml.rels'}
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files_to_keep = {
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'[Content_Types].xml',
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'_rels/.rels',
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'word/_rels/document.xml.rels',
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'word/document.xml',
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'word/fontTable.xml',
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'word/settings.xml',
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'word/styles.xml',
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}
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files_to_omit = set(map(re.compile, { # type: ignore
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'^docProps/',
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}))
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def get_meta(self):
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def get_meta(self) -> Dict[str, str]:
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"""
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Yes, I know that parsing xml with regexp ain't pretty,
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be my guest and fix it if you want.
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@ -88,38 +116,12 @@ class MSOfficeParser(ArchiveBasedAbstractParser):
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pass
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if not metadata: # better safe than sorry
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metadata[item] = 'harmful content'
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for key, value in self._get_zipinfo_meta(item).items():
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metadata[key] = value
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zipin.close()
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return metadata
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def remove_all(self):
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zin = zipfile.ZipFile(self.filename, 'r')
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zout = zipfile.ZipFile(self.output_filename, 'w')
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temp_folder = tempfile.mkdtemp()
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for item in zin.infolist():
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if item.filename[-1] == '/':
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continue # `is_dir` is added in Python3.6
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elif item.filename.startswith('docProps/'):
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continue # don't keep metadata files
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if item.filename in self.files_to_keep:
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item = self._clean_zipinfo(item)
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zout.writestr(item, zin.read(item))
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continue
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if self._clean_internal_file(item, temp_folder, zin, zout) is False:
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return False
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shutil.rmtree(temp_folder)
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zout.close()
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zin.close()
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return True
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class LibreOfficeParser(ArchiveBasedAbstractParser):
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mimetypes = {
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'application/vnd.oasis.opendocument.text',
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@ -130,10 +132,20 @@ class LibreOfficeParser(ArchiveBasedAbstractParser):
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'application/vnd.oasis.opendocument.formula',
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'application/vnd.oasis.opendocument.image',
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}
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whitelist = {'mimetype', 'manifest.rdf'}
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files_to_keep = {
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'META-INF/manifest.xml',
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'content.xml',
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'manifest.rdf',
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'mimetype',
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'settings.xml',
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'styles.xml',
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}
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files_to_omit = set(map(re.compile, { # type: ignore
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'^meta\.xml$',
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'^Configurations2/',
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}))
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def get_meta(self):
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def get_meta(self) -> Dict[str, str]:
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"""
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Yes, I know that parsing xml with regexp ain't pretty,
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be my guest and fix it if you want.
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@ -156,21 +168,3 @@ class LibreOfficeParser(ArchiveBasedAbstractParser):
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zipin.close()
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return metadata
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def remove_all(self):
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zin = zipfile.ZipFile(self.filename, 'r')
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zout = zipfile.ZipFile(self.output_filename, 'w')
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temp_folder = tempfile.mkdtemp()
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for item in zin.infolist():
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if item.filename[-1] == '/':
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continue # `is_dir` is added in Python3.6
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elif item.filename == 'meta.xml':
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continue # don't keep metadata files
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if self._clean_internal_file(item, temp_folder, zin, zout) is False:
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return False
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shutil.rmtree(temp_folder)
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zout.close()
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zin.close()
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return True
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