mirror of
https://github.com/simple-login/app.git
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f6708dd0b6
* chore: refactor DNS client to its own class * chore: adapt code calling DNS and add tests to it * chore: refactor old dkim check not to clear flag
145 lines
4.7 KiB
Python
145 lines
4.7 KiB
Python
from abc import ABC, abstractmethod
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from typing import List, Tuple, Optional
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import dns.resolver
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from app.config import NAMESERVERS
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_include_spf = "include:"
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def is_mx_equivalent(
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mx_domains: List[Tuple[int, str]], ref_mx_domains: List[Tuple[int, str]]
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) -> bool:
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"""
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Compare mx_domains with ref_mx_domains to see if they are equivalent.
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mx_domains and ref_mx_domains are list of (priority, domain)
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The priority order is taken into account but not the priority number.
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For example, [(1, domain1), (2, domain2)] is equivalent to [(10, domain1), (20, domain2)]
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"""
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mx_domains = sorted(mx_domains, key=lambda x: x[0])
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ref_mx_domains = sorted(ref_mx_domains, key=lambda x: x[0])
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if len(mx_domains) < len(ref_mx_domains):
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return False
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for i in range(len(ref_mx_domains)):
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if mx_domains[i][1] != ref_mx_domains[i][1]:
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return False
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return True
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class DNSClient(ABC):
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@abstractmethod
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def get_cname_record(self, hostname: str) -> Optional[str]:
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pass
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@abstractmethod
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def get_mx_domains(self, hostname: str) -> List[Tuple[int, str]]:
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pass
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def get_spf_domain(self, hostname: str) -> List[str]:
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"""
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return all domains listed in *include:*
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"""
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try:
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records = self.get_txt_record(hostname)
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ret = []
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for record in records:
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if record.startswith("v=spf1"):
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parts = record.split(" ")
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for part in parts:
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if part.startswith(_include_spf):
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ret.append(
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part[part.find(_include_spf) + len(_include_spf) :]
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)
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return ret
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except Exception:
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return []
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@abstractmethod
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def get_txt_record(self, hostname: str) -> List[str]:
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pass
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class NetworkDNSClient(DNSClient):
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def __init__(self, nameservers: List[str]):
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self._resolver = dns.resolver.Resolver()
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self._resolver.nameservers = nameservers
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def get_cname_record(self, hostname: str) -> Optional[str]:
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"""
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Return the CNAME record if exists for a domain, WITHOUT the trailing period at the end
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"""
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try:
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answers = self._resolver.resolve(hostname, "CNAME", search=True)
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for a in answers:
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ret = a.to_text()
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return ret[:-1]
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except Exception:
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return None
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def get_mx_domains(self, hostname: str) -> List[Tuple[int, str]]:
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"""
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return list of (priority, domain name) sorted by priority (lowest priority first)
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domain name ends with a "." at the end.
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"""
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try:
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answers = self._resolver.resolve(hostname, "MX", search=True)
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ret = []
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for a in answers:
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record = a.to_text() # for ex '20 alt2.aspmx.l.google.com.'
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parts = record.split(" ")
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ret.append((int(parts[0]), parts[1]))
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return sorted(ret, key=lambda x: x[0])
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except Exception:
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return []
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def get_txt_record(self, hostname: str) -> List[str]:
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try:
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answers = self._resolver.resolve(hostname, "TXT", search=True)
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ret = []
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for a in answers: # type: dns.rdtypes.ANY.TXT.TXT
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for record in a.strings:
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ret.append(record.decode())
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return ret
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except Exception:
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return []
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class InMemoryDNSClient(DNSClient):
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def __init__(self):
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self.cname_records: dict[str, Optional[str]] = {}
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self.mx_records: dict[str, List[Tuple[int, str]]] = {}
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self.spf_records: dict[str, List[str]] = {}
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self.txt_records: dict[str, List[str]] = {}
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def set_cname_record(self, hostname: str, cname: str):
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self.cname_records[hostname] = cname
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def set_mx_records(self, hostname: str, mx_list: List[Tuple[int, str]]):
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self.mx_records[hostname] = mx_list
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def set_txt_record(self, hostname: str, txt_list: List[str]):
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self.txt_records[hostname] = txt_list
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def get_cname_record(self, hostname: str) -> Optional[str]:
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return self.cname_records.get(hostname)
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def get_mx_domains(self, hostname: str) -> List[Tuple[int, str]]:
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mx_list = self.mx_records.get(hostname, [])
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return sorted(mx_list, key=lambda x: x[0])
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def get_txt_record(self, hostname: str) -> List[str]:
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return self.txt_records.get(hostname, [])
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def get_network_dns_client() -> NetworkDNSClient:
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return NetworkDNSClient(NAMESERVERS)
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def get_mx_domains(hostname: str) -> [(int, str)]:
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return get_network_dns_client().get_mx_domains(hostname)
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