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#!/usr/bin/env python3
# Copyright (C) 2021 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import re
import sys
# Etree isn't subject to any data leak vulnerabilities:
# +---------------------------+------------+-----------------------------------+
# | Issue | Etree | Issue description |
# +---------------------------+------------+-----------------------------------+
# | billion laughs | Vulnerable | DDOS by huge CPU and memory usage |
# +---------------------------+------------+-----------------------------------+
# | quadratic blowup | Vulnerable | DDOS by huge CPU and memory usage |
# +---------------------------+------------+-----------------------------------+
# | external entity expansion | Safe (1) | Data leak |
# +---------------------------+------------+-----------------------------------+
# | DTD retrieval | Safe | Data leak |
# +---------------------------+------------+-----------------------------------+
# | decompression bomb | Safe | DDOS by huge amount of CPU |
# +---------------------------+------------+-----------------------------------+
# (1) xml.etree.ElementTree doesn’t expand external entities and raises a
# ParserError when an entity occurs.
#
# Other XML parsers like sax, minidom, pulldom, xmlrpc have similar security
# properties: they are not vulnerable (anymore) to data leaks but they are still
# vulnerable to DDOS attacks.
# Reference: https://docs.python.org/3.8/library/xml.html#xml-vulnerabilities
import xml.etree.ElementTree
import jinja2
def usage(progname):
print ('Usage:')
print ('\t{} <path/to/default.xml>'.format(progname))
sys.exit(1)
class Manifest(object):
def __init__(self, manifest_xml_path):
self.remotes = {}
self.xml_file = open(manifest_xml_path, 'r')
tree = xml.etree.ElementTree.parse(self.xml_file)
self.root = tree.getroot()
self.defaults = self._get_defaults(self.root)
def _get_defaults(self, root):
for child in root.iter('default'):
return child
def get_remote(self, name):
if name in self.remotes.keys():
return self.remotes.get(name)
for child in self.root.iter('remote'):
if child.get('name') == name:
self.remotes[name] = child
return child
def get_project_property(self, project, prop):
if prop in project.keys():
return project.get(prop)
else:
return self.defaults.get(prop)
def get_clone_url(self, elm):
repo_path = re.sub('/*$', '', self.get_project_property(elm, 'name'))
remote_name = self.get_project_property(elm, 'remote')
remote_url = re.sub('/*$', '',
self.get_remote(remote_name).get('fetch'))
return "{}/{}".format(remote_url, repo_path)
def get_revision(self, elm):
if 'revision' in elm.keys():
return elm.get('revision')
remote = self.get_remote(self.get_project_property(elm, 'remote'))
if 'revision' in remote:
return remote.get('revision')
elif self.defaults.get('remote') == remote.get('name'):
return self.defaults.get('revision')
assert(False)
def get_base_directory(self, given_remote):
# Since the commands are generated it's a good idea to do our
# best not to produce potentially dangerous commands. The
# downside is that the list above will need to be updated
# automatically
#
# TODO: android-x86 ccache F-Droid LineageOS
whitelist = {
'aosp' : {
'fetch' : 'https://android.googlesource.com',
'dirname' : 'mirrors/AOSP',
},
'freedesktop' : {
'fetch' : 'https://gitlab.freedesktop.org',
'dirname' : 'mirrors/freesmartphone.org',
},
}
assert(given_remote.get('name') in whitelist)
whiltelist_renote = whitelist.get(given_remote.get('name'))
whitelist_fetch_url = re.sub('/*$', '', whiltelist_renote.get('fetch'))
given_remote_fetch_url = re.sub('/*$', '', given_remote.get('fetch'))
assert (whitelist_fetch_url == given_remote_fetch_url)
return whitelist.get(given_remote.get('name')).get('dirname')
def is_revision_whitelisted(self, elm):
remote = self.get_project_property(elm, 'remote')
revision = self.get_revision(elm)
if remote == 'aosp' and revision == 'refs/tags/android-11.0.0_r17':
return True
if remote == 'freedesktop' and \
revision == '32819fe45972e0c706423d71075788a5885f7b86':
return True
return False
def is_revision_blacklisted(self, elm):
revision = self.get_revision(elm)
if revision == 'master':
return True
return False
def get_clone_commands(self, elm):
commands = []
url = self.get_clone_url(elm)
remote = self.get_remote(self.get_project_property(elm, 'remote'))
base_directory = self.get_base_directory(remote)
repo_directory = self.get_project_property(elm,
'name').replace('/', '_')
revision = self.get_revision(elm)
# Guard against updating the master branch of mirrors that could be used
# by several Replicant versions at the same time by forcing users to
# manually declare revisions here. The revisions have to be either
# whitelisted or blacklisted else we abort.
if not self.is_revision_whitelisted(elm) and \
not self.is_revision_blacklisted(elm):
print('/!\ The "{}" revision of {}/{} is not known by {}'.format(
revision, base_directory, repo_directory, sys.argv[0]))
print(' Please add it either to the whitelist in {}'.format(
'is_revision_whitelisted'))
print(' or to the blacklist in {}'.format(
'is_revision_blacklisted'))
assert(False)
elif self.is_revision_blacklisted(elm):
return []
commands.append("if [ ! -d {}/{}.git ] ; then".format(
base_directory, repo_directory))
commands.append(" git clone --mirror {} {}/{}.git".format(
url, base_directory, repo_directory))
commands.append("else")
commands.append(" git -C {}/{}.git fetch {} {}".format(
base_directory, repo_directory, url, revision))
commands.append(" touch {}/{}.git/git-daemon-export-ok".format(
base_directory, repo_directory))
commands.append("fi")
return commands
def parse(self):
for child in self.root.iter('project'):
print("# {}".format(self.get_project_property(child, 'name')))
for command in self.get_clone_commands(child):
print(command)
print('')
def close(self):
self.xml_file.close()
if __name__ == '__main__':
if len(sys.argv) != 2:
usage(sys.argv[0])
manifest_xml_path = sys.argv[1]
manifest = Manifest(manifest_xml_path)
manifest.parse()
manifest.close()
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