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# Copyright (C) 2014 Canonical Ltd.
# Author: Michael Vogt <michael.vogt@ubuntu.com>
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 3 of the License.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""Integration tests for the click signature checking."""
import copy
import os
import shutil
import subprocess
import tarfile
from textwrap import dedent
from .helpers import (
require_root,
ClickTestCase,
)
def makedirs(path):
try:
os.makedirs(path)
except OSError:
pass
def get_keyid_from_gpghome(gpg_home):
"""Return the public keyid of a given gpg home dir"""
output = subprocess.check_output(
["gpg", "--home", gpg_home, "--list-keys", "--with-colons"],
universal_newlines=True)
for line in output.splitlines():
if not line.startswith("pub:"):
continue
return line.split(":")[4]
raise ValueError("Cannot find public key in output: '%s'" % output)
class Debsigs:
"""Tiny wrapper around the debsigs CLI"""
def __init__(self, gpghome, keyid):
self.keyid = keyid
self.gpghome = gpghome
self.policy = "/etc/debsig/policies/%s/generic.pol" % self.keyid
def sign(self, filepath, signature_type="origin"):
"""Sign the click at filepath"""
env = copy.copy(os.environ)
env["GNUPGHOME"] = os.path.abspath(self.gpghome)
subprocess.check_call(
["debsigs",
"--sign=%s" % signature_type,
"--default-key=%s" % self.keyid,
filepath], env=env)
def install_signature_policy(self):
"""Install/update the system-wide signature policy"""
xmls = dedent("""\
<?xml version="1.0"?>
<!DOCTYPE Policy SYSTEM "http://www.debian.org/debsig/1.0/policy.dtd">
<Policy xmlns="http://www.debian.org/debsig/1.0/">
<Origin Name="test-origin" id="{keyid}" Description="Example policy"/>
<Selection>
<Required Type="origin" File="{filename}" id="{keyid}"/>
</Selection>
<Verification>
<Required Type="origin" File="{filename}" id="{keyid}"/>
</Verification>
</Policy>
""".format(keyid=self.keyid, filename="origin.pub"))
makedirs(os.path.dirname(self.policy))
with open(self.policy, "w") as f:
f.write(xmls)
self.pubkey_path = (
"/usr/share/debsig/keyrings/%s/origin.pub" % self.keyid)
makedirs(os.path.dirname(self.pubkey_path))
shutil.copy(
os.path.join(self.gpghome, "pubring.gpg"), self.pubkey_path)
def uninstall_signature_policy(self):
# FIXME: update debsig-verify so that it can work from a different
# root than "/" so that the tests do not have to use the
# system root
os.remove(self.policy)
os.remove(self.pubkey_path)
class ClickSignaturesTestCase(ClickTestCase):
@classmethod
def setUpClass(cls):
super(ClickSignaturesTestCase, cls).setUpClass()
require_root()
def assertClickNoSignatureError(self, cmd_args):
with self.assertRaises(subprocess.CalledProcessError) as cm:
output = subprocess.check_output(
[self.click_binary] + cmd_args,
stderr=subprocess.STDOUT, universal_newlines=True)
output = cm.exception.output
expected_error_message = ("debsig: Origin Signature check failed. "
"This deb might not be signed.")
self.assertIn(expected_error_message, output)
def assertClickInvalidSignatureError(self, cmd_args):
with self.assertRaises(subprocess.CalledProcessError) as cm:
output = subprocess.check_output(
[self.click_binary] + cmd_args,
stderr=subprocess.STDOUT, universal_newlines=True)
print(output)
output = cm.exception.output
expected_error_message = "Signature verification error: "
self.assertIn(expected_error_message, output)
class TestSignatureVerificationNoSignature(ClickSignaturesTestCase):
@classmethod
def setUpClass(cls):
super(TestSignatureVerificationNoSignature, cls).setUpClass()
require_root()
def test_debsig_verify_no_sig(self):
name = "org.example.debsig-no-sig"
path_to_click = self._make_click(name, framework="")
self.assertClickNoSignatureError(["verify", path_to_click])
def test_debsig_install_no_sig(self):
name = "org.example.debsig-no-sig"
path_to_click = self._make_click(name, framework="")
self.assertClickNoSignatureError(["install", path_to_click])
def test_debsig_install_can_install_with_sig_override(self):
name = "org.example.debsig-no-sig"
path_to_click = self._make_click(name, framework="")
user = os.environ.get("USER", "root")
subprocess.check_call(
[self.click_binary, "install",
"--allow-unauthenticated", "--user=%s" % user,
path_to_click])
self.addCleanup(
subprocess.call, [self.click_binary, "unregister",
"--user=%s" % user, name])
class TestSignatureVerification(ClickSignaturesTestCase):
@classmethod
def setUpClass(cls):
super(TestSignatureVerification, cls).setUpClass()
require_root()
def setUp(self):
super(TestSignatureVerification, self).setUp()
self.user = os.environ.get("USER", "root")
# the valid origin keyring
self.datadir = os.path.join(os.path.dirname(__file__), "data")
origin_keyring_dir = os.path.abspath(
os.path.join(self.datadir, "origin-keyring"))
keyid = get_keyid_from_gpghome(origin_keyring_dir)
self.debsigs = Debsigs(origin_keyring_dir, keyid)
self.debsigs.install_signature_policy()
def tearDown(self):
self.debsigs.uninstall_signature_policy()
def test_debsig_install_valid_signature(self):
name = "org.example.debsig-valid-sig"
path_to_click = self._make_click(name, framework="")
self.debsigs.sign(path_to_click)
subprocess.check_call(
[self.click_binary, "install",
"--user=%s" % self.user,
path_to_click])
self.addCleanup(
subprocess.call, [self.click_binary, "unregister",
"--user=%s" % self.user, name])
output = subprocess.check_output(
[self.click_binary, "list", "--user=%s" % self.user],
universal_newlines=True)
self.assertIn(name, output)
def test_debsig_install_signature_not_in_keyring(self):
name = "org.example.debsig-no-keyring-sig"
path_to_click = self._make_click(name, framework="")
evil_keyring_dir = os.path.join(self.datadir, "evil-keyring")
keyid = get_keyid_from_gpghome(evil_keyring_dir)
debsig_bad = Debsigs(evil_keyring_dir, keyid)
debsig_bad.sign(path_to_click)
# and ensure its really not there
self.assertClickInvalidSignatureError(["install", path_to_click])
output = subprocess.check_output(
[self.click_binary, "list", "--user=%s" % self.user],
universal_newlines=True)
self.assertNotIn(name, output)
def test_debsig_install_not_a_signature(self):
name = "org.example.debsig-invalid-sig"
path_to_click = self._make_click(name, framework="")
invalid_sig = os.path.join(self.temp_dir, "_gpgorigin")
with open(invalid_sig, "w") as f:
f.write("no-valid-signature")
# add a invalid sig
subprocess.check_call(["ar", "-r", path_to_click, invalid_sig])
self.assertClickInvalidSignatureError(["install", path_to_click])
output = subprocess.check_output(
[self.click_binary, "list", "--user=%s" % self.user],
universal_newlines=True)
self.assertNotIn(name, output)
def test_debsig_install_signature_altered_click(self):
def modify_ar_member(member):
subprocess.check_call(
["ar", "-x", path_to_click, "control.tar.gz"],
cwd=self.temp_dir)
altered_member = os.path.join(self.temp_dir, member)
with open(altered_member, "ba") as f:
f.write(b"\0")
subprocess.check_call(["ar", "-r", path_to_click, altered_member])
# ensure that all members we care about are checked by debsig-verify
for member in ["control.tar.gz", "data.tar.gz", "debian-binary"]:
name = "org.example.debsig-altered-click"
path_to_click = self._make_click(name, framework="")
self.debsigs.sign(path_to_click)
modify_ar_member(member)
self.assertClickInvalidSignatureError(["install", path_to_click])
output = subprocess.check_output(
[self.click_binary, "list", "--user=%s" % self.user],
universal_newlines=True)
self.assertNotIn(name, output)
def make_nasty_data_tar(self, compression):
new_data_tar = os.path.join(self.temp_dir, "data.tar." + compression)
evilfile = os.path.join(self.temp_dir, "README.evil")
with open(evilfile, "w") as f:
f.write("I am a nasty README")
with tarfile.open(new_data_tar, "w:"+compression) as tar:
tar.add(evilfile)
return new_data_tar
def test_debsig_install_signature_injected_data_tar(self):
name = "org.example.debsig-injected-data-click"
path_to_click = self._make_click(name, framework="")
self.debsigs.sign(path_to_click)
new_data = self.make_nasty_data_tar("bz2")
# insert before the real data.tar.gz and ensure this is caught
# NOTE: that right now this will not be caught by debsig-verify
# but later in audit() by debian.debfile.DebFile()
subprocess.check_call(["ar",
"-r",
"-b", "data.tar.gz",
path_to_click,
new_data])
output = subprocess.check_output(
["ar", "-t", path_to_click], universal_newlines=True)
self.assertEqual(output.splitlines(),
["debian-binary",
"_click-binary",
"control.tar.gz",
"data.tar.bz2",
"data.tar.gz",
"_gpgorigin"])
with self.assertRaises(subprocess.CalledProcessError):
output = subprocess.check_output(
[self.click_binary, "install", path_to_click],
stderr=subprocess.STDOUT, universal_newlines=True)
output = subprocess.check_output(
[self.click_binary, "list", "--user=%s" % self.user],
universal_newlines=True)
self.assertNotIn(name, output)
def test_debsig_install_signature_replaced_data_tar(self):
name = "org.example.debsig-replaced-data-click"
path_to_click = self._make_click(name, framework="")
self.debsigs.sign(path_to_click)
new_data = self.make_nasty_data_tar("bz2")
# replace data.tar.gz with data.tar.bz2 and ensure this is caught
subprocess.check_call(["ar",
"-d",
path_to_click,
"data.tar.gz",
])
subprocess.check_call(["ar",
"-r",
path_to_click,
new_data])
output = subprocess.check_output(
["ar", "-t", path_to_click], universal_newlines=True)
self.assertEqual(output.splitlines(),
["debian-binary",
"_click-binary",
"control.tar.gz",
"_gpgorigin",
"data.tar.bz2",
])
with self.assertRaises(subprocess.CalledProcessError) as cm:
output = subprocess.check_output(
[self.click_binary, "install", path_to_click],
stderr=subprocess.STDOUT, universal_newlines=True)
self.assertIn("Signature verification error", cm.exception.output)
output = subprocess.check_output(
[self.click_binary, "list", "--user=%s" % self.user],
universal_newlines=True)
self.assertNotIn(name, output)
def test_debsig_install_signature_prepend_sig(self):
# this test is probably not really needed, it tries to trick
# the system by prepending a valid signature that is not
# in the keyring. But given that debsig-verify only reads
# the first packet of any given _gpg$foo signature it's
# equivalent to test_debsig_install_signature_not_in_keyring test
name = "org.example.debsig-replaced-data-prepend-sig-click"
path_to_click = self._make_click(name, framework="")
self.debsigs.sign(path_to_click)
new_data = self.make_nasty_data_tar("gz")
# replace data.tar.gz
subprocess.check_call(["ar",
"-r",
path_to_click,
new_data,
])
# get previous good _gpgorigin for the old data
subprocess.check_call(
["ar", "-x", path_to_click, "_gpgorigin"], cwd=self.temp_dir)
with open(os.path.join(self.temp_dir, "_gpgorigin"), "br") as f:
good_gpg_origin = f.read()
# and append a valid signature from a non-keyring key
evil_keyring_dir = os.path.join(self.datadir, "evil-keyring")
debsig_bad = Debsigs(evil_keyring_dir, "18B38B9AC1B67A0D")
debsig_bad.sign(path_to_click)
subprocess.check_call(
["ar", "-x", path_to_click, "_gpgorigin"], cwd=self.temp_dir)
with open(os.path.join(self.temp_dir, "_gpgorigin"), "br") as f:
evil_gpg_origin = f.read()
with open(os.path.join(self.temp_dir, "_gpgorigin"), "wb") as f:
f.write(evil_gpg_origin)
f.write(good_gpg_origin)
subprocess.check_call(
["ar", "-r", path_to_click, "_gpgorigin"], cwd=self.temp_dir)
# now ensure that the verification fails as well
with self.assertRaises(subprocess.CalledProcessError) as cm:
output = subprocess.check_output(
[self.click_binary, "install", path_to_click],
stderr=subprocess.STDOUT, universal_newlines=True)
self.assertIn("Signature verification error", cm.exception.output)
output = subprocess.check_output(
[self.click_binary, "list", "--user=%s" % self.user],
universal_newlines=True)
self.assertNotIn(name, output)
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