Scott Kitterman
298 lines
13 KiB
Python
298 lines
13 KiB
Python
# This software is provided 'as-is', without any express or implied
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# warranty. In no event will the author be held liable for any damages
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# arising from the use of this software.
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#
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# Permission is granted to anyone to use this software for any purpose,
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# including commercial applications, and to alter it and redistribute it
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# freely, subject to the following restrictions:
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#
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# 1. The origin of this software must not be misrepresented; you must not
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# claim that you wrote the original software. If you use this software
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# in a product, an acknowledgment in the product documentation would be
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# appreciated but is not required.
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# 2. Altered source versions must be plainly marked as such, and must not be
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# misrepresented as being the original software.
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# 3. This notice may not be removed or altered from any source distribution.
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#
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# Copyright (c) 2011 William Grant <me@williamgrant.id.au>
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# Copyright (c) 2018 Scott Kitterman <scott@kitterman.com>
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import email
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import os.path
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import unittest
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import time
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import dkim
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def read_test_data(filename):
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"""Get the content of the given test data file.
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The files live in dkim/tests/data.
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"""
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path = os.path.join(os.path.dirname(__file__), 'data', filename)
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with open(path, 'rb') as f:
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return f.read()
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class TestFold(unittest.TestCase):
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def test_short_line(self):
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self.assertEqual(
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b"foo", dkim.fold(b"foo"))
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def test_long_line(self):
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# The function is terribly broken, not passing even this simple
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# test.
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self.assertEqual(
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b"foo" * 24 + b"\r\n foo", dkim.fold(b"foo" * 25))
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class TestSignAndVerify(unittest.TestCase):
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"""End-to-end signature and verification tests."""
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def setUp(self):
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self.message = read_test_data("ed25519test.msg")
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self.message2 = read_test_data("ed25519test2.msg")
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self.message3 = read_test_data("rfc6376.msg")
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self.message4 = read_test_data("rfc6376.signed.msg")
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self.key = read_test_data("ed25519test.key")
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self.rfckey = read_test_data("rfc8032_7_1.key")
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def dnsfunc(self, domain):
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sample_dns = """\
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k=ed25519; \
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p=yi50DjK5O9pqbFpNHklsv9lqaS0ArSYu02qp1S0DW1Y="""
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_dns_responses = {
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'example._domainkey.canonical.com.': sample_dns,
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'test._domainkey.example.net.': """v=DKIM1; k=ed25519; \
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p=yi50DjK5O9pqbFpNHklsv9lqaS0ArSYu02qp1S0DW1Y=""",
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'sed._domainkey.test.ex.': read_test_data("eximtest.dns"),
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'brisbane._domainkey.football.example.com.': """v=DKIM1; k=ed25519; \
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p=11qYAYKxCrfVS/7TyWQHOg7hcvPapiMlrwIaaPcHURo="""
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}
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try:
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domain = domain.decode('ascii')
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except UnicodeDecodeError:
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return None
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self.assertTrue(domain in _dns_responses,domain)
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return _dns_responses[domain]
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def test_verifies(self):
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# A message verifies after being signed.
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for header_algo in (b"simple", b"relaxed"):
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for body_algo in (b"simple", b"relaxed"):
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sig = dkim.sign(
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self.message, b"test", b"example.net", self.key,
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canonicalize=(header_algo, body_algo), signature_algorithm=b'ed25519-sha256')
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res = dkim.verify(sig + self.message, dnsfunc=self.dnsfunc)
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self.assertTrue(res)
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def test_rfc8032_verifies(self):
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# A message using RFC 8032 sample keys verifies after being signed.
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for header_algo in (b"simple", b"relaxed"):
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for body_algo in (b"simple", b"relaxed"):
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sig = dkim.sign(
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self.message3, b"brisbane", b"football.example.com", self.rfckey,
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canonicalize=(header_algo, body_algo), signature_algorithm=b'ed25519-sha256')
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res = dkim.verify(sig + self.message3, dnsfunc=self.dnsfunc)
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self.assertTrue(res)
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def test_rfc8032_previous_verifies(self):
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# A message previously signed using RFC 8032 sample keys verifies after being signed.
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for header_algo in (b"simple", b"relaxed"):
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for body_algo in (b"simple", b"relaxed"):
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sig = dkim.sign(
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self.message3, b"brisbane", b"football.example.com", self.rfckey,
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canonicalize=(header_algo, body_algo), signature_algorithm=b'ed25519-sha256')
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d = dkim.DKIM(self.message4)
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res = d.verify(dnsfunc=self.dnsfunc)
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self.assertTrue(res)
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def test_simple_signature(self):
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# A message verifies after being signed with SHOULD headers
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for header_algo in (b"simple", b"relaxed"):
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for body_algo in (b"simple", b"relaxed"):
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sig = dkim.sign(
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self.message, b"test", b"example.net", self.key,
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canonicalize=(header_algo, body_algo),
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include_headers=(b'from',) + dkim.DKIM.SHOULD,
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signature_algorithm=b'ed25519-sha256')
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res = dkim.verify(sig + self.message, dnsfunc=self.dnsfunc)
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self.assertTrue(res)
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def test_verify_third_party(self):
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# Message signed by prototype Exim implementation
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res = dkim.verify(self.message2, dnsfunc=self.dnsfunc)
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self.assertTrue(res)
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def test_add_body_length(self):
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sig = dkim.sign(
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self.message, b"test", b"example.net", self.key, length=True,
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signature_algorithm=b'ed25519-sha256')
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msg = email.message_from_string(self.message.decode('utf-8'))
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self.assertIn('; l=%s' % len(msg.get_payload() + '\n'), sig.decode('utf-8'))
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res = dkim.verify(sig + self.message, dnsfunc=self.dnsfunc)
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self.assertTrue(res)
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def test_altered_body_fails(self):
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# An altered body fails verification.
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for header_algo in (b"simple", b"relaxed"):
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for body_algo in (b"simple", b"relaxed"):
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sig = dkim.sign(
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self.message, b"test", b"example.net", self.key,
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signature_algorithm=b'ed25519-sha256')
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res = dkim.verify(
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sig + self.message + b"foo", dnsfunc=self.dnsfunc)
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self.assertFalse(res)
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def test_badly_encoded_domain_fails(self):
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# Domains should be ASCII. Bad ASCII causes verification to fail.
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sig = dkim.sign(self.message, b"test", b"example.net\xe9", self.key,
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signature_algorithm=b'ed25519-sha256')
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res = dkim.verify(sig + self.message, dnsfunc=self.dnsfunc)
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self.assertFalse(res)
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def test_dkim_signature_canonicalization(self):
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# <https://bugs.launchpad.net/ubuntu/+source/pydkim/+bug/587783>
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# Relaxed-mode header signing is wrong
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# <https://bugs.launchpad.net/dkimpy/+bug/939128>
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# Simple-mode signature header verification is wrong
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# (should ignore FWS anywhere in signature tag: b=)
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sample_msg = b"""\
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From: mbp@canonical.com
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To: scottk@example.net
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Subject: this is my
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test message
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""".replace(b'\n', b'\r\n')
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sample_privkey = b"""\
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fL+5V9EquCZAovKik3pA6Lk9zwCzoEtjIuIqK9ZXHHA=\
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"""
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sample_pubkey = """\
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yi50DjK5O9pqbFpNHklsv9lqaS0ArSYu02qp1S0DW1Y=\
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"""
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for header_mode in [dkim.Relaxed, dkim.Simple]:
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dkim_header = dkim.sign(sample_msg, b'example', b'canonical.com',
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sample_privkey, canonicalize=(header_mode, dkim.Relaxed),
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signature_algorithm=b'ed25519-sha256')
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# Folding dkim_header affects b= tag only, since dkim.sign folds
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# sig_value with empty b= before hashing, and then appends the
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# signature. So folding dkim_header again adds FWS to
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# the b= tag only. This should be ignored even with
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# simple canonicalization.
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# http://tools.ietf.org/html/rfc4871#section-3.5
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signed = dkim.fold(dkim_header) + sample_msg
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result = dkim.verify(signed,dnsfunc=self.dnsfunc)
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self.assertTrue(result)
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dkim_header = dkim.fold(dkim_header)
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# use a tab for last fold to test tab in FWS bug
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pos = dkim_header.rindex(b'\r\n ')
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dkim_header = dkim_header[:pos]+b'\r\n\t'+dkim_header[pos+3:]
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result = dkim.verify(dkim_header + sample_msg,
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dnsfunc=self.dnsfunc)
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self.assertTrue(result)
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def test_extra_headers(self):
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# <https://bugs.launchpad.net/dkimpy/+bug/737311>
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# extra headers above From caused failure
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#message = read_test_data("test_extra.message")
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message = read_test_data("message.mbox")
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for header_algo in (b"simple", b"relaxed"):
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for body_algo in (b"simple", b"relaxed"):
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d = dkim.DKIM(message)
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# bug requires a repeated header to manifest
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d.should_not_sign.remove(b'received')
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sig = d.sign(b"test", b"example.net", self.key,
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signature_algorithm=b'ed25519-sha256',
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include_headers=d.all_sign_headers(),
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canonicalize=(header_algo, body_algo))
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dv = dkim.DKIM(sig + message)
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res = dv.verify(dnsfunc=self.dnsfunc)
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self.assertEquals(d.include_headers,dv.include_headers)
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s = dkim.select_headers(d.headers,d.include_headers)
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sv = dkim.select_headers(dv.headers,dv.include_headers)
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self.assertEquals(s,sv)
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self.assertTrue(res)
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def test_multiple_from_fails(self):
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# <https://bugs.launchpad.net/dkimpy/+bug/644046>
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# additional From header fields should cause verify failure
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hfrom = b'From: "Resident Evil" <sales@spammer.com>\r\n'
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h,b = self.message.split(b'\n\n',1)
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for header_algo in (b"simple", b"relaxed"):
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for body_algo in (b"simple", b"relaxed"):
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sig = dkim.sign(
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self.message, b"test", b"example.net", self.key,
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signature_algorithm=b'ed25519-sha256')
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# adding an unknown header still verifies
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h1 = h+b'\r\n'+b'X-Foo: bar'
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message = b'\n\n'.join((h1,b))
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res = dkim.verify(sig+message, dnsfunc=self.dnsfunc)
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self.assertTrue(res)
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# adding extra from at end should not verify
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h1 = h+b'\r\n'+hfrom.strip()
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message = b'\n\n'.join((h1,b))
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res = dkim.verify(sig+message, dnsfunc=self.dnsfunc)
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self.assertFalse(res)
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# add extra from in front should not verify either
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h1 = hfrom+h
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message = b'\n\n'.join((h1,b))
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res = dkim.verify(sig+message, dnsfunc=self.dnsfunc)
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self.assertFalse(res)
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def test_no_from_fails(self):
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# Body From is mandatory to be in the message and mandatory to sign
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sigerror = False
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sig = ''
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message = read_test_data('test_nofrom.message')
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selector = 'test'
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domain = 'example.net'
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identity = None
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try:
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sig = dkim.sign(message, selector, domain,
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read_test_data('ed25519test.key'), identity = identity,
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signature_algorithm=b'ed25519-sha256')
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except dkim.ParameterError as x:
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sigerror = True
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self.assertTrue(sigerror)
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def test_validate_signature_fields(self):
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sig = {b'v': b'1',
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b'a': b'ed25519-sha256',
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b'b': b'K/UUOt8lCtgjp3kSTogqBm9lY1Yax/NwZ+bKm39/WKzo5KYe3L/6RoIA/0oiDX4kO\n \t Qut49HCV6ZUe6dY9V5qWBwLanRs1sCnObaOGMpFfs8tU4TWpDSVXaNZAqn15XVW0WH\n \t EzOzUfVuatpa1kF4voIgSbmZHR1vN3WpRtcTBe/I=',
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b'bh': b'n0HUwGCP28PkesXBPH82Kboy8LhNFWU9zUISIpAez7M=',
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b'c': b'simple/simple',
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b'd': b'kitterman.com',
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b'i': b'scott@Kitterman.com',
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b'h': b'From:To:Subject:Date:Cc:MIME-Version:Content-Type:\n \t Content-Transfer-Encoding:Message-Id',
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b's': b'2007-00',
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b't': b'1299525798'}
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dkim.validate_signature_fields(sig)
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# try new version
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sigVer = sig.copy()
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sigVer[b'v'] = 2
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self.assertRaises(dkim.ValidationError, dkim.validate_signature_fields, sigVer)
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# try with x
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sigX = sig.copy()
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sigX[b'x'] = b'1399525798'
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dkim.validate_signature_fields(sig)
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# try with late t
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sigX[b't'] = b'1400000000'
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self.assertRaises(dkim.ValidationError, dkim.validate_signature_fields, sigX)
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# try without t
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now = int(time.time())
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sigX[b'x'] = str(now+400000).encode('ascii')
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dkim.validate_signature_fields(sigX)
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# try when expired a day ago
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sigX[b'x'] = str(now - 24*3600).encode('ascii')
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self.assertRaises(dkim.ValidationError, dkim.validate_signature_fields, sigX)
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def test_suite():
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from unittest import TestLoader
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return TestLoader().loadTestsFromName(__name__)
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