CERT.py

# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license

# Copyright (C) 2003-2007, 2009-2011 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

import struct
import base64

import dns.exception
import dns.immutable
import dns.dnssec
import dns.rdata
import dns.tokenizer

_ctype_by_value = {
    1: 'PKIX',
    2: 'SPKI',
    3: 'PGP',
    253: 'URI',
    254: 'OID',
}

_ctype_by_name = {
    'PKIX': 1,
    'SPKI': 2,
    'PGP': 3,
    'URI': 253,
    'OID': 254,
}


def _ctype_from_text(what):
    v = _ctype_by_name.get(what)
    if v is not None:
        return v
    return int(what)


def _ctype_to_text(what):
    v = _ctype_by_value.get(what)
    if v is not None:
        return v
    return str(what)


@dns.immutable.immutable
class CERT(dns.rdata.Rdata):

    """CERT record"""

    # see RFC 2538

    __slots__ = ['certificate_type', 'key_tag', 'algorithm', 'certificate']

    def __init__(self, rdclass, rdtype, certificate_type, key_tag, algorithm,
                 certificate):
        super().__init__(rdclass, rdtype)
        self.certificate_type = self._as_uint16(certificate_type)
        self.key_tag = self._as_uint16(key_tag)
        self.algorithm = self._as_uint8(algorithm)
        self.certificate = self._as_bytes(certificate)

    def to_text(self, origin=None, relativize=True, **kw):
        certificate_type = _ctype_to_text(self.certificate_type)
        return "%s %d %s %s" % (certificate_type, self.key_tag,
                                dns.dnssec.algorithm_to_text(self.algorithm),
                                dns.rdata._base64ify(self.certificate, **kw))

    @classmethod
    def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True,
                  relativize_to=None):
        certificate_type = _ctype_from_text(tok.get_string())
        key_tag = tok.get_uint16()
        algorithm = dns.dnssec.algorithm_from_text(tok.get_string())
        b64 = tok.concatenate_remaining_identifiers().encode()
        certificate = base64.b64decode(b64)
        return cls(rdclass, rdtype, certificate_type, key_tag,
                   algorithm, certificate)

    def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
        prefix = struct.pack("!HHB", self.certificate_type, self.key_tag,
                             self.algorithm)
        file.write(prefix)
        file.write(self.certificate)

    @classmethod
    def from_wire_parser(cls, rdclass, rdtype, parser, origin=None):
        (certificate_type, key_tag, algorithm) = parser.get_struct("!HHB")
        certificate = parser.get_remaining()
        return cls(rdclass, rdtype, certificate_type, key_tag, algorithm,
                   certificate)