162 lines
4.9 KiB
Python
162 lines
4.9 KiB
Python
"""
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`cryptography.x509 <https://github.com/pyca/cryptography>`_-specific code.
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"""
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from __future__ import absolute_import, division, print_function
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import warnings
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from cryptography.x509 import (
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DNSName,
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ExtensionOID,
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IPAddress,
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NameOID,
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ObjectIdentifier,
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OtherName,
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UniformResourceIdentifier,
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)
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from cryptography.x509.extensions import ExtensionNotFound
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from pyasn1.codec.der.decoder import decode
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from pyasn1.type.char import IA5String
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from ._common import (
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DNS_ID,
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CertificateError,
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DNSPattern,
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IPAddress_ID,
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IPAddressPattern,
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SRVPattern,
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URIPattern,
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verify_service_identity,
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)
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from .exceptions import SubjectAltNameWarning
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__all__ = ["verify_certificate_hostname"]
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def verify_certificate_hostname(certificate, hostname):
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"""
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Verify whether *certificate* is valid for *hostname*.
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.. note:: Nothing is verified about the *authority* of the certificate;
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the caller must verify that the certificate chains to an appropriate
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trust root themselves.
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:param cryptography.x509.Certificate certificate: A cryptography X509
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certificate object.
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:param unicode hostname: The hostname that *certificate* should be valid
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for.
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:raises service_identity.VerificationError: If *certificate* is not valid
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for *hostname*.
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:raises service_identity.CertificateError: If *certificate* contains
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invalid/unexpected data.
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:returns: ``None``
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"""
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verify_service_identity(
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cert_patterns=extract_ids(certificate),
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obligatory_ids=[DNS_ID(hostname)],
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optional_ids=[],
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)
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def verify_certificate_ip_address(certificate, ip_address):
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"""
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Verify whether *certificate* is valid for *ip_address*.
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.. note:: Nothing is verified about the *authority* of the certificate;
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the caller must verify that the certificate chains to an appropriate
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trust root themselves.
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:param cryptography.x509.Certificate certificate: A cryptography X509
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certificate object.
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:param unicode ip_address: The IP address that *connection* should be valid
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for. Can be an IPv4 or IPv6 address.
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:raises service_identity.VerificationError: If *certificate* is not valid
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for *ip_address*.
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:raises service_identity.CertificateError: If *certificate* contains
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invalid/unexpected data.
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:returns: ``None``
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.. versionadded:: 18.1.0
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"""
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verify_service_identity(
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cert_patterns=extract_ids(certificate),
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obligatory_ids=[IPAddress_ID(ip_address)],
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optional_ids=[],
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)
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ID_ON_DNS_SRV = ObjectIdentifier("1.3.6.1.5.5.7.8.7") # id_on_dnsSRV
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def extract_ids(cert):
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"""
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Extract all valid IDs from a certificate for service verification.
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If *cert* doesn't contain any identifiers, the ``CN``s are used as DNS-IDs
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as fallback.
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:param cryptography.x509.Certificate cert: The certificate to be dissected.
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:return: List of IDs.
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"""
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ids = []
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try:
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ext = cert.extensions.get_extension_for_oid(
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ExtensionOID.SUBJECT_ALTERNATIVE_NAME
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)
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except ExtensionNotFound:
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pass
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else:
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ids.extend(
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[
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DNSPattern(name.encode("utf-8"))
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for name in ext.value.get_values_for_type(DNSName)
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]
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)
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ids.extend(
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[
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URIPattern(uri.encode("utf-8"))
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for uri in ext.value.get_values_for_type(
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UniformResourceIdentifier
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)
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]
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)
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ids.extend(
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[
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IPAddressPattern(ip)
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for ip in ext.value.get_values_for_type(IPAddress)
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]
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)
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for other in ext.value.get_values_for_type(OtherName):
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if other.type_id == ID_ON_DNS_SRV:
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srv, _ = decode(other.value)
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if isinstance(srv, IA5String):
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ids.append(SRVPattern(srv.asOctets()))
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else: # pragma: nocover
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raise CertificateError("Unexpected certificate content.")
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if not ids:
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# https://tools.ietf.org/search/rfc6125#section-6.4.4
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# A client MUST NOT seek a match for a reference identifier of CN-ID if
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# the presented identifiers include a DNS-ID, SRV-ID, URI-ID, or any
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# application-specific identifier types supported by the client.
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cns = [
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n.value
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for n in cert.subject.get_attributes_for_oid(NameOID.COMMON_NAME)
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]
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cn = next(iter(cns), b"<not given>")
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ids = [DNSPattern(n.encode("utf-8")) for n in cns]
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warnings.warn(
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"Certificate with CN {!r} has no `subjectAltName`, falling back "
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"to check for a `commonName` for now. This feature is being "
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"removed by major browsers and deprecated by RFC 2818.".format(cn),
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SubjectAltNameWarning,
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)
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return ids
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