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"""
Copyright (c) 2023 Proton AG
This file is part of Proton.
Proton 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, either version 3 of the License, or
(at your option) any later version.
Proton 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 ProtonVPN. If not, see <https://www.gnu.org/licenses/>.
"""
import base64
import dataclasses
import ipaddress
import typing
import pytest
from proton.session.transports.utils.dns import DNSParser, DNSResponseError
@dataclasses.dataclass
class _DnsParsingTestData:
name: str
domain: str
#expected_ar_domain: bytes
expected_dns_request: bytes
dns_reply: bytes
expected_parsed_reply: typing.List[dict]
ar_old_domain_data = _DnsParsingTestData(
name = "legacy domain",
domain = "api.protonvpn.ch",
#expected_ar_domain = b'\x1bdMFYGSLTQOJXXI33OOZYG4LTDNA\tprotonpro\x03xyz\x00',
expected_dns_request = b'\xfa\x83\x01 \x00\x01\x00\x00\x00\x00\x00\x00\x1bdMFYGSLTQOJXXI33OOZYG4LTDNA\tprotonpro\x03xyz\x00\x00\x10\x00\x01',
dns_reply = b'\xfa\x83\x81\x80\x00\x01\x00\x02\x00\x00\x00\x00\x1bdMFYGSLTQOJXXI33OOZYG4LTDNA\tprotonpro\x03xyz\x00\x00\x10\x00\x01\xc0\x0c\x00\x10\x00\x01\x00\x00\x00x\x0032ec2-3-127-37-78.eu-central-1.compute.amazonaws.com\xc0\x0c\x00\x10\x00\x01\x00\x00\x00x\x0054ec2-54-93-234-150.eu-central-1.compute.amazonaws.com',
expected_parsed_reply = [(120, "ec2-3-127-37-78.eu-central-1.compute.amazonaws.com"),
(120, "ec2-54-93-234-150.eu-central-1.compute.amazonaws.com"),]
)
ar_current_domain_data1 = _DnsParsingTestData(
name = "current domain",
domain = "vpn-api.proton.me",
#expected_ar_domain = b'\x1ddOZYG4LLBOBUS44DSN52G63RONVSQ\tprotonpro\x03xyz\x00',
expected_dns_request = b'\xcc\x72\x01 \x00\x01\x00\x00\x00\x00\x00\x00\x1ddOZYG4LLBOBUS44DSN52G63RONVSQ\tprotonpro\x03xyz\x00\x00\x10\x00\x01',
dns_reply = b'\xcc\x72\x81\x80\x00\x01\x00\x03\x00\x00\x00\x00\x1ddOZYG4LLBOBUS44DSN52G63RONVSQ\tprotonpro\x03xyz\x00\x00\x10\x00\x01\xc0\x0c\x00\x05\x00\x01\x00\x00\x00x\x00\x06\x03vpn\xc0*\xc0I\x00\x10\x00\x01\x00\x00\x00x\x00\x0e\r18.185.75.113\xc0I\x00\x10\x00\x01\x00\x00\x00x\x00\x0e\r18.196.59.154',
expected_parsed_reply = [(120, '18.185.75.113'),
(120, '18.196.59.154'),],
)
ar_current_domain_data2 = _DnsParsingTestData(
name = "current domain",
domain = "vpn-api.proton.me",
#expected_ar_domain = b'\x1ddOZYG4LLBOBUS44DSN52G63RONVSQ\tprotonpro\x03xyz\x00',
expected_dns_request = b'\x00\x00\x01 \x00\x01\x00\x00\x00\x00\x00\x00\x1ddOZYG4LLBOBUS44DSN52G63RONVSQ\tprotonpro\x03xyz\x00\x00\x10\x00\x01',
dns_reply = b'\x00\x00\x81\x80\x00\x01\x00\x03\x00\x00\x00\x00\x1ddOZYG4LLBOBUS44DSN52G63RONVSQ\tprotonpro\x03xyz\x00\x00\x10\x00\x01\xc0\x0c\x00\x05\x00\x01\x00\x00\x00x\x00\x06\x03vpn\xc0*\xc0I\x00\x10\x00\x01\x00\x00\x00x\x00\x0e\r35.158.124.21\xc0I\x00\x10\x00\x01\x00\x00\x00x\x00\x0b\n3.72.109.7',
expected_parsed_reply = [(120, '35.158.124.21'),
(120, '3.72.109.7')],
)
standard_legacy_domain = _DnsParsingTestData(
name = "legacy domain",
domain = "api.protonvpn.ch",
expected_dns_request = b'\xdf\r\x01 \x00\x01\x00\x00\x00\x00\x00\x00\x03api\tprotonvpn\x02ch\x00\x00\x01\x00\x01',
dns_reply = b'\xdf\r\x81\x80\x00\x01\x00\x01\x00\x03\x00\x03\x03api\tprotonvpn\x02ch\x00\x00\x01\x00\x01\xc0\x0c\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb9\x9f\x9f\xaa\xc0\x10\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06\x03ns2\xc0\x10\xc0\x10\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06\x03ns3\xc0\x10\xc0\x10\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06\x03ns1\xc0\x10\xc0b\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb9F*\x96\xc0>\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb0w\xc8\x96\xc0P\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xcd\x84/\x01',
expected_parsed_reply = [(1200, ipaddress.ip_address('185.159.159.170')),],
)
standard_current_domain = _DnsParsingTestData(
name = "current domain",
domain = "vpn-api.proton.me",
expected_dns_request = b'jW\x01 \x00\x01\x00\x00\x00\x00\x00\x00\x07vpn-api\x06proton\x02me\x00\x00\x01\x00\x01',
dns_reply = b'jW\x81\x80\x00\x01\x00\x01\x00\x03\x00\x03\x07vpn-api\x06proton\x02me\x00\x00\x01\x00\x01\xc0\x0c\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb9\x9f\x9f\x94\xc0\x14\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06\x03ns3\xc0\x14\xc0\x14\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06\x03ns1\xc0\x14\xc0\x14\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06\x03ns2\xc0\x14\xc0Q\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb9F*\x96\xc0c\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb0w\xc8\x96\xc0?\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xcd\x84/\x01',
expected_parsed_reply = [(1200, ipaddress.ip_address('185.159.159.148')),],
)
other_reply_data = [
_DnsParsingTestData(
name="full DNS reply legacy domain",
domain = "api.protonvpn.ch",
expected_dns_request = None,
dns_reply = \
b"\x09\x8c\x81\x80\x00\x01\x00\x01\x00\x00\x00\x01\x07\x76\x70\x6e" \
b"\x2d\x61\x70\x69\x06\x70\x72\x6f\x74\x6f\x6e\x02\x6d\x65\x00\x00" \
b"\x01\x00\x01\xc0\x0c\x00\x01\x00\x01\x00\x00\x03\x8b\x00\x04\xb9" \
b"\x9f\x9f\x94\x00\x00\x29\x10\x00\x00\x00\x00\x00\x00\x00",
expected_parsed_reply = [(907, ipaddress.ip_address('185.159.159.148'))],
),
_DnsParsingTestData(
name="full DNS reply current domain",
domain = "vpn-api.proton.me",
expected_dns_request = None,
dns_reply = \
b"\xaa\xfc\x81\x80\x00\x01\x00\x01\x00\x03\x00\x04\x03\x61\x70\x69" \
b"\x09\x70\x72\x6f\x74\x6f\x6e\x76\x70\x6e\x02\x63\x68\x00\x00\x01" \
b"\x00\x01\xc0\x0c\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb9\x9f" \
b"\x9f\xaa\xc0\x10\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06\x03\x6e" \
b"\x73\x32\xc0\x10\xc0\x10\x00\x02\x00\x01\x00\x00\x04\xb0\x00\x06" \
b"\x03\x6e\x73\x31\xc0\x10\xc0\x10\x00\x02\x00\x01\x00\x00\x04\xb0" \
b"\x00\x06\x03\x6e\x73\x33\xc0\x10\xc0\x50\x00\x01\x00\x01\x00\x00" \
b"\x04\xb0\x00\x04\xb9\x46\x2a\x96\xc0\x3e\x00\x01\x00\x01\x00\x00" \
b"\x04\xb0\x00\x04\xb0\x77\xc8\x96\xc0\x62\x00\x01\x00\x01\x00\x00" \
b"\x04\xb0\x00\x04\xcd\x84\x2f\x01\x00\x00\x29\x10\x00\x00\x00\x00" \
b"\x00\x00\x00",
expected_parsed_reply = [(1200, ipaddress.ip_address('185.159.159.170'))],
),
]
class TestDNSParser:
def _test_ar_input_data(self, input_data: _DnsParsingTestData):
ar_domain = b'd' + base64.b32encode(input_data.domain.encode('ascii')).strip(b'=') + b".protonpro.xyz"
print(f"Testing Alternative Routing DNS for {input_data.name} : {input_data.domain} => AR domain = {ar_domain}")
dns_query = DNSParser.build_query(ar_domain, qtype=16, qclass=1) # TXT IN
print(f"DNS query : {dns_query}")
# the request 2 first bytes are randomly generated and may not match
assert dns_query[2:] == input_data.expected_dns_request[2:]
assert len(dns_query) == len(input_data.expected_dns_request)
dns_answers = DNSParser.parse(input_data.dns_reply)
print(f"DNS answers : {dns_answers}")
assert set(dns_answers) == set(input_data.expected_parsed_reply)
def test_ar_legacy_domain(self):
self._test_ar_input_data(input_data=ar_old_domain_data)
def test_ar_current_domain1(self):
self._test_ar_input_data(input_data=ar_current_domain_data1)
def test_ar_current_domain2(self):
self._test_ar_input_data(input_data=ar_current_domain_data2)
def _test_normal_input_data(self, input_data: _DnsParsingTestData):
print(f"Testing standard DNS for {input_data.name} : {input_data.domain}")
print(input_data.expected_dns_request)
dns_query = DNSParser.build_query(input_data.domain, qtype=1, qclass=1) # A IN
print(f"DNS query : {dns_query}")
# the request 2 first bytes are randomly generated and may not match
assert dns_query[2:] == input_data.expected_dns_request[2:]
assert len(dns_query) == len(input_data.expected_dns_request)
dns_answers = DNSParser.parse(input_data.dns_reply)
print(f"DNS answers : {dns_answers}")
assert set(dns_answers) == set(input_data.expected_parsed_reply)
def test_normal_query_legacy_domain(self):
self._test_normal_input_data(standard_legacy_domain)
def test_normal_query_current_domain(self):
self._test_normal_input_data(standard_current_domain)
def test_generic_parsing(self):
for input_data in other_reply_data:
print(f"Parsing other DNS reply : {input_data.name}")
dns_answers = DNSParser.parse(input_data.dns_reply)
print(f"DNS answers : {dns_answers}")
assert set(dns_answers) == set(input_data.expected_parsed_reply)
@pytest.mark.parametrize("description, invalid_input", [
("Empty reply", b''),
("Super small reply (1)", b'x'),
("Super small reply (7)", b'\xfa\x83\x81\x80\x00\x01\x00'),
("Unicode Decode error", b'\xfa\x83\x81\x80\x00\x01\x00\x02\x00\x00\x00\x00\x1bdMFYGSLTQOJXXI33OOZYG4LTDNA\tprotonpro\x03xyz\x00\x00\x10\x00\x01\xc0\x0c\x00\x10\x00\x01\x00\x00\x00x\x0032ec2\xcc3-127-37-78.eu-central-1.compute.amazonaws.com\xc0\x0c\x00\x10\x00\x01\x00\x00\x00x\x0054ec2-54-93-234-150.eu-central-1.compute.amazonaws.com'),
("Wrong query reply", b'\xfa\x83\x81\x80\x00\x01\x00\x02\x00\x00\x00\x00\x1bdMFYGSLTQOJXXI33OOZYG4LTDNA\nprotonpro\x03xyz'),
("Truncated query reply", b'\xfa\x83\x81\x80\x00\x01\x00\x02\x00\x00\x00\x00\x1bdMFYGSLTQOJXXI33OOZYG4LTDNA\tproto'),
("Truncated TXT record value", b'\x00\x00\x81\x80\x00\x01\x00\x03\x00\x00\x00\x00\x1ddOZYG4LLBOBUS44DSN52G63RONVSQ\tprotonpro\x03xyz\x00\x00\x10\x00\x01\xc0\x0c\x00\x05\x00\x01\x00\x00\x00x\x00\x06\x03vpn\xc0*\xc0I\x00\x10\x00\x01\x00\x00\x00x\x00\x0e\r35.15'),
("Truncated A record value", b'jW\x81\x80\x00\x01\x00\x01\x00\x03\x00\x03\x07vpn-api\x06proton\x02me\x00\x00\x01\x00\x01\xc0\x0c\x00\x01\x00\x01\x00\x00\x04\xb0\x00\x04\xb9\x9f\x9f'),
("Truncated A record headers", b'jW\x81\x80\x00\x01\x00\x01\x00\x03\x00\x03\x07vpn-api\x06proton\x02me\x00\x00\x01\x00\x01\xc0\x0c\x00\x01\x00'),
])
def test_incorrect_records(self, description: str, invalid_input: bytes):
print(f"{description}")
with pytest.raises(DNSResponseError):
_ = DNSParser.parse(invalid_input)
@pytest.mark.parametrize("hostname, valid", [
("ec2-3-127-37-78.eu-central-1.compute.amazonaws.com", True),
("hostnames.can.end.with.one.period.", True),
("a"*257, False), # hostnames have a 256-char limit
("-hostname", False), # hostnames cannot start with hyphen
("hostname-", False), # hostnames cannot end with hyphen
("a"*64 + ".blah.com", False), # hostname segments have a 63-char limit
("blah..com", False), # hostname segments should have a lest 1 char
("special-chars!.com", False), # hostname segments only allow alphanumeric chars and hyphens
("vpn-api.proton.me/malicious/", False) # hostname with potentially malicious path
])
def test_valid_hostname_in_A_record(self, hostname, valid):
assert DNSParser._is_valid_hostname(hostname) is valid
|
