forked from STI/Astroport.ONE
1508 lines
49 KiB
Python
1508 lines
49 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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from __future__ import annotations
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import binascii
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import enum
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import os
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import re
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import typing
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import warnings
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from base64 import encodebytes as _base64_encode
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from dataclasses import dataclass
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from cryptography import utils
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from cryptography.exceptions import UnsupportedAlgorithm
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from cryptography.hazmat.primitives import hashes
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from cryptography.hazmat.primitives.asymmetric import (
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dsa,
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ec,
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ed25519,
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padding,
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rsa,
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)
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from cryptography.hazmat.primitives.asymmetric import utils as asym_utils
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from cryptography.hazmat.primitives.ciphers import (
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AEADDecryptionContext,
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Cipher,
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algorithms,
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modes,
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)
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from cryptography.hazmat.primitives.serialization import (
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Encoding,
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KeySerializationEncryption,
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NoEncryption,
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PrivateFormat,
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PublicFormat,
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_KeySerializationEncryption,
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)
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try:
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from bcrypt import kdf as _bcrypt_kdf
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_bcrypt_supported = True
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except ImportError:
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_bcrypt_supported = False
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def _bcrypt_kdf(
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password: bytes,
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salt: bytes,
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desired_key_bytes: int,
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rounds: int,
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ignore_few_rounds: bool = False,
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) -> bytes:
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raise UnsupportedAlgorithm("Need bcrypt module")
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_SSH_ED25519 = b"ssh-ed25519"
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_SSH_RSA = b"ssh-rsa"
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_SSH_DSA = b"ssh-dss"
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_ECDSA_NISTP256 = b"ecdsa-sha2-nistp256"
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_ECDSA_NISTP384 = b"ecdsa-sha2-nistp384"
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_ECDSA_NISTP521 = b"ecdsa-sha2-nistp521"
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_CERT_SUFFIX = b"-cert-v01@openssh.com"
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# These are not key types, only algorithms, so they cannot appear
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# as a public key type
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_SSH_RSA_SHA256 = b"rsa-sha2-256"
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_SSH_RSA_SHA512 = b"rsa-sha2-512"
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_SSH_PUBKEY_RC = re.compile(rb"\A(\S+)[ \t]+(\S+)")
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_SK_MAGIC = b"openssh-key-v1\0"
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_SK_START = b"-----BEGIN OPENSSH PRIVATE KEY-----"
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_SK_END = b"-----END OPENSSH PRIVATE KEY-----"
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_BCRYPT = b"bcrypt"
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_NONE = b"none"
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_DEFAULT_CIPHER = b"aes256-ctr"
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_DEFAULT_ROUNDS = 16
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# re is only way to work on bytes-like data
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_PEM_RC = re.compile(_SK_START + b"(.*?)" + _SK_END, re.DOTALL)
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# padding for max blocksize
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_PADDING = memoryview(bytearray(range(1, 1 + 16)))
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@dataclass
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class _SSHCipher:
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alg: type[algorithms.AES]
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key_len: int
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mode: type[modes.CTR] | type[modes.CBC] | type[modes.GCM]
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block_len: int
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iv_len: int
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tag_len: int | None
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is_aead: bool
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# ciphers that are actually used in key wrapping
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_SSH_CIPHERS: dict[bytes, _SSHCipher] = {
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b"aes256-ctr": _SSHCipher(
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alg=algorithms.AES,
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key_len=32,
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mode=modes.CTR,
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block_len=16,
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iv_len=16,
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tag_len=None,
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is_aead=False,
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),
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b"aes256-cbc": _SSHCipher(
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alg=algorithms.AES,
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key_len=32,
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mode=modes.CBC,
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block_len=16,
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iv_len=16,
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tag_len=None,
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is_aead=False,
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),
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b"aes256-gcm@openssh.com": _SSHCipher(
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alg=algorithms.AES,
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key_len=32,
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mode=modes.GCM,
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block_len=16,
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iv_len=12,
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tag_len=16,
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is_aead=True,
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),
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}
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# map local curve name to key type
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_ECDSA_KEY_TYPE = {
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"secp256r1": _ECDSA_NISTP256,
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"secp384r1": _ECDSA_NISTP384,
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"secp521r1": _ECDSA_NISTP521,
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}
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def _get_ssh_key_type(key: SSHPrivateKeyTypes | SSHPublicKeyTypes) -> bytes:
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if isinstance(key, ec.EllipticCurvePrivateKey):
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key_type = _ecdsa_key_type(key.public_key())
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elif isinstance(key, ec.EllipticCurvePublicKey):
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key_type = _ecdsa_key_type(key)
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elif isinstance(key, (rsa.RSAPrivateKey, rsa.RSAPublicKey)):
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key_type = _SSH_RSA
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elif isinstance(key, (dsa.DSAPrivateKey, dsa.DSAPublicKey)):
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key_type = _SSH_DSA
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elif isinstance(
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key, (ed25519.Ed25519PrivateKey, ed25519.Ed25519PublicKey)
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):
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key_type = _SSH_ED25519
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else:
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raise ValueError("Unsupported key type")
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return key_type
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def _ecdsa_key_type(public_key: ec.EllipticCurvePublicKey) -> bytes:
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"""Return SSH key_type and curve_name for private key."""
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curve = public_key.curve
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if curve.name not in _ECDSA_KEY_TYPE:
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raise ValueError(
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f"Unsupported curve for ssh private key: {curve.name!r}"
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)
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return _ECDSA_KEY_TYPE[curve.name]
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def _ssh_pem_encode(
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data: bytes,
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prefix: bytes = _SK_START + b"\n",
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suffix: bytes = _SK_END + b"\n",
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) -> bytes:
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return b"".join([prefix, _base64_encode(data), suffix])
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def _check_block_size(data: bytes, block_len: int) -> None:
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"""Require data to be full blocks"""
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if not data or len(data) % block_len != 0:
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raise ValueError("Corrupt data: missing padding")
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def _check_empty(data: bytes) -> None:
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"""All data should have been parsed."""
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if data:
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raise ValueError("Corrupt data: unparsed data")
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def _init_cipher(
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ciphername: bytes,
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password: bytes | None,
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salt: bytes,
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rounds: int,
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) -> Cipher[modes.CBC | modes.CTR | modes.GCM]:
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"""Generate key + iv and return cipher."""
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if not password:
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raise ValueError("Key is password-protected.")
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ciph = _SSH_CIPHERS[ciphername]
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seed = _bcrypt_kdf(
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password, salt, ciph.key_len + ciph.iv_len, rounds, True
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)
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return Cipher(
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ciph.alg(seed[: ciph.key_len]),
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ciph.mode(seed[ciph.key_len :]),
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)
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def _get_u32(data: memoryview) -> tuple[int, memoryview]:
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"""Uint32"""
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if len(data) < 4:
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raise ValueError("Invalid data")
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return int.from_bytes(data[:4], byteorder="big"), data[4:]
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def _get_u64(data: memoryview) -> tuple[int, memoryview]:
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"""Uint64"""
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if len(data) < 8:
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raise ValueError("Invalid data")
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return int.from_bytes(data[:8], byteorder="big"), data[8:]
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def _get_sshstr(data: memoryview) -> tuple[memoryview, memoryview]:
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"""Bytes with u32 length prefix"""
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n, data = _get_u32(data)
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if n > len(data):
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raise ValueError("Invalid data")
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return data[:n], data[n:]
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def _get_mpint(data: memoryview) -> tuple[int, memoryview]:
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"""Big integer."""
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val, data = _get_sshstr(data)
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if val and val[0] > 0x7F:
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raise ValueError("Invalid data")
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return int.from_bytes(val, "big"), data
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def _to_mpint(val: int) -> bytes:
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"""Storage format for signed bigint."""
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if val < 0:
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raise ValueError("negative mpint not allowed")
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if not val:
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return b""
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nbytes = (val.bit_length() + 8) // 8
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return utils.int_to_bytes(val, nbytes)
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class _FragList:
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"""Build recursive structure without data copy."""
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flist: list[bytes]
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def __init__(self, init: list[bytes] | None = None) -> None:
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self.flist = []
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if init:
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self.flist.extend(init)
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def put_raw(self, val: bytes) -> None:
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"""Add plain bytes"""
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self.flist.append(val)
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def put_u32(self, val: int) -> None:
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"""Big-endian uint32"""
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self.flist.append(val.to_bytes(length=4, byteorder="big"))
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def put_u64(self, val: int) -> None:
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"""Big-endian uint64"""
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self.flist.append(val.to_bytes(length=8, byteorder="big"))
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def put_sshstr(self, val: bytes | _FragList) -> None:
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"""Bytes prefixed with u32 length"""
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if isinstance(val, (bytes, memoryview, bytearray)):
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self.put_u32(len(val))
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self.flist.append(val)
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else:
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self.put_u32(val.size())
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self.flist.extend(val.flist)
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def put_mpint(self, val: int) -> None:
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"""Big-endian bigint prefixed with u32 length"""
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self.put_sshstr(_to_mpint(val))
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def size(self) -> int:
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"""Current number of bytes"""
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return sum(map(len, self.flist))
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def render(self, dstbuf: memoryview, pos: int = 0) -> int:
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"""Write into bytearray"""
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for frag in self.flist:
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flen = len(frag)
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start, pos = pos, pos + flen
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dstbuf[start:pos] = frag
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return pos
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def tobytes(self) -> bytes:
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"""Return as bytes"""
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buf = memoryview(bytearray(self.size()))
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self.render(buf)
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return buf.tobytes()
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class _SSHFormatRSA:
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"""Format for RSA keys.
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Public:
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mpint e, n
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Private:
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mpint n, e, d, iqmp, p, q
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"""
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def get_public(self, data: memoryview):
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"""RSA public fields"""
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e, data = _get_mpint(data)
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n, data = _get_mpint(data)
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return (e, n), data
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def load_public(
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self, data: memoryview
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) -> tuple[rsa.RSAPublicKey, memoryview]:
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"""Make RSA public key from data."""
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(e, n), data = self.get_public(data)
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public_numbers = rsa.RSAPublicNumbers(e, n)
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public_key = public_numbers.public_key()
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return public_key, data
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def load_private(
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self, data: memoryview, pubfields
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) -> tuple[rsa.RSAPrivateKey, memoryview]:
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"""Make RSA private key from data."""
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n, data = _get_mpint(data)
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e, data = _get_mpint(data)
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d, data = _get_mpint(data)
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iqmp, data = _get_mpint(data)
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p, data = _get_mpint(data)
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q, data = _get_mpint(data)
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if (e, n) != pubfields:
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raise ValueError("Corrupt data: rsa field mismatch")
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dmp1 = rsa.rsa_crt_dmp1(d, p)
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dmq1 = rsa.rsa_crt_dmq1(d, q)
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public_numbers = rsa.RSAPublicNumbers(e, n)
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private_numbers = rsa.RSAPrivateNumbers(
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p, q, d, dmp1, dmq1, iqmp, public_numbers
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)
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private_key = private_numbers.private_key()
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return private_key, data
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def encode_public(
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self, public_key: rsa.RSAPublicKey, f_pub: _FragList
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) -> None:
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"""Write RSA public key"""
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pubn = public_key.public_numbers()
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f_pub.put_mpint(pubn.e)
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f_pub.put_mpint(pubn.n)
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def encode_private(
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self, private_key: rsa.RSAPrivateKey, f_priv: _FragList
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) -> None:
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"""Write RSA private key"""
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private_numbers = private_key.private_numbers()
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public_numbers = private_numbers.public_numbers
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f_priv.put_mpint(public_numbers.n)
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f_priv.put_mpint(public_numbers.e)
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f_priv.put_mpint(private_numbers.d)
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f_priv.put_mpint(private_numbers.iqmp)
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f_priv.put_mpint(private_numbers.p)
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f_priv.put_mpint(private_numbers.q)
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class _SSHFormatDSA:
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"""Format for DSA keys.
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Public:
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mpint p, q, g, y
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Private:
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mpint p, q, g, y, x
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"""
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def get_public(self, data: memoryview) -> tuple[tuple, memoryview]:
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"""DSA public fields"""
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p, data = _get_mpint(data)
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q, data = _get_mpint(data)
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g, data = _get_mpint(data)
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y, data = _get_mpint(data)
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return (p, q, g, y), data
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def load_public(
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self, data: memoryview
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) -> tuple[dsa.DSAPublicKey, memoryview]:
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"""Make DSA public key from data."""
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(p, q, g, y), data = self.get_public(data)
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parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
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public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)
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self._validate(public_numbers)
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public_key = public_numbers.public_key()
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return public_key, data
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def load_private(
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self, data: memoryview, pubfields
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) -> tuple[dsa.DSAPrivateKey, memoryview]:
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"""Make DSA private key from data."""
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(p, q, g, y), data = self.get_public(data)
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x, data = _get_mpint(data)
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if (p, q, g, y) != pubfields:
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raise ValueError("Corrupt data: dsa field mismatch")
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parameter_numbers = dsa.DSAParameterNumbers(p, q, g)
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public_numbers = dsa.DSAPublicNumbers(y, parameter_numbers)
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self._validate(public_numbers)
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private_numbers = dsa.DSAPrivateNumbers(x, public_numbers)
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private_key = private_numbers.private_key()
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return private_key, data
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def encode_public(
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self, public_key: dsa.DSAPublicKey, f_pub: _FragList
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) -> None:
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"""Write DSA public key"""
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public_numbers = public_key.public_numbers()
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parameter_numbers = public_numbers.parameter_numbers
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self._validate(public_numbers)
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f_pub.put_mpint(parameter_numbers.p)
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f_pub.put_mpint(parameter_numbers.q)
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f_pub.put_mpint(parameter_numbers.g)
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f_pub.put_mpint(public_numbers.y)
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def encode_private(
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self, private_key: dsa.DSAPrivateKey, f_priv: _FragList
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) -> None:
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"""Write DSA private key"""
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self.encode_public(private_key.public_key(), f_priv)
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f_priv.put_mpint(private_key.private_numbers().x)
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def _validate(self, public_numbers: dsa.DSAPublicNumbers) -> None:
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parameter_numbers = public_numbers.parameter_numbers
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if parameter_numbers.p.bit_length() != 1024:
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raise ValueError("SSH supports only 1024 bit DSA keys")
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|
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class _SSHFormatECDSA:
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"""Format for ECDSA keys.
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Public:
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str curve
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bytes point
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Private:
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str curve
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bytes point
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mpint secret
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"""
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def __init__(self, ssh_curve_name: bytes, curve: ec.EllipticCurve):
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self.ssh_curve_name = ssh_curve_name
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self.curve = curve
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def get_public(self, data: memoryview) -> tuple[tuple, memoryview]:
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"""ECDSA public fields"""
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curve, data = _get_sshstr(data)
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point, data = _get_sshstr(data)
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if curve != self.ssh_curve_name:
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raise ValueError("Curve name mismatch")
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if point[0] != 4:
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raise NotImplementedError("Need uncompressed point")
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return (curve, point), data
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def load_public(
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self, data: memoryview
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) -> tuple[ec.EllipticCurvePublicKey, memoryview]:
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"""Make ECDSA public key from data."""
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(_, point), data = self.get_public(data)
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public_key = ec.EllipticCurvePublicKey.from_encoded_point(
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self.curve, point.tobytes()
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)
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return public_key, data
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def load_private(
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self, data: memoryview, pubfields
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) -> tuple[ec.EllipticCurvePrivateKey, memoryview]:
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"""Make ECDSA private key from data."""
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(curve_name, point), data = self.get_public(data)
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secret, data = _get_mpint(data)
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if (curve_name, point) != pubfields:
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raise ValueError("Corrupt data: ecdsa field mismatch")
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private_key = ec.derive_private_key(secret, self.curve)
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return private_key, data
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def encode_public(
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self, public_key: ec.EllipticCurvePublicKey, f_pub: _FragList
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) -> None:
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"""Write ECDSA public key"""
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point = public_key.public_bytes(
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Encoding.X962, PublicFormat.UncompressedPoint
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)
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f_pub.put_sshstr(self.ssh_curve_name)
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f_pub.put_sshstr(point)
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def encode_private(
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self, private_key: ec.EllipticCurvePrivateKey, f_priv: _FragList
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) -> None:
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"""Write ECDSA private key"""
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public_key = private_key.public_key()
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private_numbers = private_key.private_numbers()
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|
self.encode_public(public_key, f_priv)
|
|
f_priv.put_mpint(private_numbers.private_value)
|
|
|
|
|
|
class _SSHFormatEd25519:
|
|
"""Format for Ed25519 keys.
|
|
|
|
Public:
|
|
bytes point
|
|
Private:
|
|
bytes point
|
|
bytes secret_and_point
|
|
"""
|
|
|
|
def get_public(self, data: memoryview) -> tuple[tuple, memoryview]:
|
|
"""Ed25519 public fields"""
|
|
point, data = _get_sshstr(data)
|
|
return (point,), data
|
|
|
|
def load_public(
|
|
self, data: memoryview
|
|
) -> tuple[ed25519.Ed25519PublicKey, memoryview]:
|
|
"""Make Ed25519 public key from data."""
|
|
(point,), data = self.get_public(data)
|
|
public_key = ed25519.Ed25519PublicKey.from_public_bytes(
|
|
point.tobytes()
|
|
)
|
|
return public_key, data
|
|
|
|
def load_private(
|
|
self, data: memoryview, pubfields
|
|
) -> tuple[ed25519.Ed25519PrivateKey, memoryview]:
|
|
"""Make Ed25519 private key from data."""
|
|
(point,), data = self.get_public(data)
|
|
keypair, data = _get_sshstr(data)
|
|
|
|
secret = keypair[:32]
|
|
point2 = keypair[32:]
|
|
if point != point2 or (point,) != pubfields:
|
|
raise ValueError("Corrupt data: ed25519 field mismatch")
|
|
private_key = ed25519.Ed25519PrivateKey.from_private_bytes(secret)
|
|
return private_key, data
|
|
|
|
def encode_public(
|
|
self, public_key: ed25519.Ed25519PublicKey, f_pub: _FragList
|
|
) -> None:
|
|
"""Write Ed25519 public key"""
|
|
raw_public_key = public_key.public_bytes(
|
|
Encoding.Raw, PublicFormat.Raw
|
|
)
|
|
f_pub.put_sshstr(raw_public_key)
|
|
|
|
def encode_private(
|
|
self, private_key: ed25519.Ed25519PrivateKey, f_priv: _FragList
|
|
) -> None:
|
|
"""Write Ed25519 private key"""
|
|
public_key = private_key.public_key()
|
|
raw_private_key = private_key.private_bytes(
|
|
Encoding.Raw, PrivateFormat.Raw, NoEncryption()
|
|
)
|
|
raw_public_key = public_key.public_bytes(
|
|
Encoding.Raw, PublicFormat.Raw
|
|
)
|
|
f_keypair = _FragList([raw_private_key, raw_public_key])
|
|
|
|
self.encode_public(public_key, f_priv)
|
|
f_priv.put_sshstr(f_keypair)
|
|
|
|
|
|
_KEY_FORMATS = {
|
|
_SSH_RSA: _SSHFormatRSA(),
|
|
_SSH_DSA: _SSHFormatDSA(),
|
|
_SSH_ED25519: _SSHFormatEd25519(),
|
|
_ECDSA_NISTP256: _SSHFormatECDSA(b"nistp256", ec.SECP256R1()),
|
|
_ECDSA_NISTP384: _SSHFormatECDSA(b"nistp384", ec.SECP384R1()),
|
|
_ECDSA_NISTP521: _SSHFormatECDSA(b"nistp521", ec.SECP521R1()),
|
|
}
|
|
|
|
|
|
def _lookup_kformat(key_type: bytes):
|
|
"""Return valid format or throw error"""
|
|
if not isinstance(key_type, bytes):
|
|
key_type = memoryview(key_type).tobytes()
|
|
if key_type in _KEY_FORMATS:
|
|
return _KEY_FORMATS[key_type]
|
|
raise UnsupportedAlgorithm(f"Unsupported key type: {key_type!r}")
|
|
|
|
|
|
SSHPrivateKeyTypes = typing.Union[
|
|
ec.EllipticCurvePrivateKey,
|
|
rsa.RSAPrivateKey,
|
|
dsa.DSAPrivateKey,
|
|
ed25519.Ed25519PrivateKey,
|
|
]
|
|
|
|
|
|
def load_ssh_private_key(
|
|
data: bytes,
|
|
password: bytes | None,
|
|
backend: typing.Any = None,
|
|
) -> SSHPrivateKeyTypes:
|
|
"""Load private key from OpenSSH custom encoding."""
|
|
utils._check_byteslike("data", data)
|
|
if password is not None:
|
|
utils._check_bytes("password", password)
|
|
|
|
m = _PEM_RC.search(data)
|
|
if not m:
|
|
raise ValueError("Not OpenSSH private key format")
|
|
p1 = m.start(1)
|
|
p2 = m.end(1)
|
|
data = binascii.a2b_base64(memoryview(data)[p1:p2])
|
|
if not data.startswith(_SK_MAGIC):
|
|
raise ValueError("Not OpenSSH private key format")
|
|
data = memoryview(data)[len(_SK_MAGIC) :]
|
|
|
|
# parse header
|
|
ciphername, data = _get_sshstr(data)
|
|
kdfname, data = _get_sshstr(data)
|
|
kdfoptions, data = _get_sshstr(data)
|
|
nkeys, data = _get_u32(data)
|
|
if nkeys != 1:
|
|
raise ValueError("Only one key supported")
|
|
|
|
# load public key data
|
|
pubdata, data = _get_sshstr(data)
|
|
pub_key_type, pubdata = _get_sshstr(pubdata)
|
|
kformat = _lookup_kformat(pub_key_type)
|
|
pubfields, pubdata = kformat.get_public(pubdata)
|
|
_check_empty(pubdata)
|
|
|
|
if (ciphername, kdfname) != (_NONE, _NONE):
|
|
ciphername_bytes = ciphername.tobytes()
|
|
if ciphername_bytes not in _SSH_CIPHERS:
|
|
raise UnsupportedAlgorithm(
|
|
f"Unsupported cipher: {ciphername_bytes!r}"
|
|
)
|
|
if kdfname != _BCRYPT:
|
|
raise UnsupportedAlgorithm(f"Unsupported KDF: {kdfname!r}")
|
|
blklen = _SSH_CIPHERS[ciphername_bytes].block_len
|
|
tag_len = _SSH_CIPHERS[ciphername_bytes].tag_len
|
|
# load secret data
|
|
edata, data = _get_sshstr(data)
|
|
# see https://bugzilla.mindrot.org/show_bug.cgi?id=3553 for
|
|
# information about how OpenSSH handles AEAD tags
|
|
if _SSH_CIPHERS[ciphername_bytes].is_aead:
|
|
tag = bytes(data)
|
|
if len(tag) != tag_len:
|
|
raise ValueError("Corrupt data: invalid tag length for cipher")
|
|
else:
|
|
_check_empty(data)
|
|
_check_block_size(edata, blklen)
|
|
salt, kbuf = _get_sshstr(kdfoptions)
|
|
rounds, kbuf = _get_u32(kbuf)
|
|
_check_empty(kbuf)
|
|
ciph = _init_cipher(ciphername_bytes, password, salt.tobytes(), rounds)
|
|
dec = ciph.decryptor()
|
|
edata = memoryview(dec.update(edata))
|
|
if _SSH_CIPHERS[ciphername_bytes].is_aead:
|
|
assert isinstance(dec, AEADDecryptionContext)
|
|
_check_empty(dec.finalize_with_tag(tag))
|
|
else:
|
|
# _check_block_size requires data to be a full block so there
|
|
# should be no output from finalize
|
|
_check_empty(dec.finalize())
|
|
else:
|
|
# load secret data
|
|
edata, data = _get_sshstr(data)
|
|
_check_empty(data)
|
|
blklen = 8
|
|
_check_block_size(edata, blklen)
|
|
ck1, edata = _get_u32(edata)
|
|
ck2, edata = _get_u32(edata)
|
|
if ck1 != ck2:
|
|
raise ValueError("Corrupt data: broken checksum")
|
|
|
|
# load per-key struct
|
|
key_type, edata = _get_sshstr(edata)
|
|
if key_type != pub_key_type:
|
|
raise ValueError("Corrupt data: key type mismatch")
|
|
private_key, edata = kformat.load_private(edata, pubfields)
|
|
# We don't use the comment
|
|
_, edata = _get_sshstr(edata)
|
|
|
|
# yes, SSH does padding check *after* all other parsing is done.
|
|
# need to follow as it writes zero-byte padding too.
|
|
if edata != _PADDING[: len(edata)]:
|
|
raise ValueError("Corrupt data: invalid padding")
|
|
|
|
if isinstance(private_key, dsa.DSAPrivateKey):
|
|
warnings.warn(
|
|
"SSH DSA keys are deprecated and will be removed in a future "
|
|
"release.",
|
|
utils.DeprecatedIn40,
|
|
stacklevel=2,
|
|
)
|
|
|
|
return private_key
|
|
|
|
|
|
def _serialize_ssh_private_key(
|
|
private_key: SSHPrivateKeyTypes,
|
|
password: bytes,
|
|
encryption_algorithm: KeySerializationEncryption,
|
|
) -> bytes:
|
|
"""Serialize private key with OpenSSH custom encoding."""
|
|
utils._check_bytes("password", password)
|
|
if isinstance(private_key, dsa.DSAPrivateKey):
|
|
warnings.warn(
|
|
"SSH DSA key support is deprecated and will be "
|
|
"removed in a future release",
|
|
utils.DeprecatedIn40,
|
|
stacklevel=4,
|
|
)
|
|
|
|
key_type = _get_ssh_key_type(private_key)
|
|
kformat = _lookup_kformat(key_type)
|
|
|
|
# setup parameters
|
|
f_kdfoptions = _FragList()
|
|
if password:
|
|
ciphername = _DEFAULT_CIPHER
|
|
blklen = _SSH_CIPHERS[ciphername].block_len
|
|
kdfname = _BCRYPT
|
|
rounds = _DEFAULT_ROUNDS
|
|
if (
|
|
isinstance(encryption_algorithm, _KeySerializationEncryption)
|
|
and encryption_algorithm._kdf_rounds is not None
|
|
):
|
|
rounds = encryption_algorithm._kdf_rounds
|
|
salt = os.urandom(16)
|
|
f_kdfoptions.put_sshstr(salt)
|
|
f_kdfoptions.put_u32(rounds)
|
|
ciph = _init_cipher(ciphername, password, salt, rounds)
|
|
else:
|
|
ciphername = kdfname = _NONE
|
|
blklen = 8
|
|
ciph = None
|
|
nkeys = 1
|
|
checkval = os.urandom(4)
|
|
comment = b""
|
|
|
|
# encode public and private parts together
|
|
f_public_key = _FragList()
|
|
f_public_key.put_sshstr(key_type)
|
|
kformat.encode_public(private_key.public_key(), f_public_key)
|
|
|
|
f_secrets = _FragList([checkval, checkval])
|
|
f_secrets.put_sshstr(key_type)
|
|
kformat.encode_private(private_key, f_secrets)
|
|
f_secrets.put_sshstr(comment)
|
|
f_secrets.put_raw(_PADDING[: blklen - (f_secrets.size() % blklen)])
|
|
|
|
# top-level structure
|
|
f_main = _FragList()
|
|
f_main.put_raw(_SK_MAGIC)
|
|
f_main.put_sshstr(ciphername)
|
|
f_main.put_sshstr(kdfname)
|
|
f_main.put_sshstr(f_kdfoptions)
|
|
f_main.put_u32(nkeys)
|
|
f_main.put_sshstr(f_public_key)
|
|
f_main.put_sshstr(f_secrets)
|
|
|
|
# copy result info bytearray
|
|
slen = f_secrets.size()
|
|
mlen = f_main.size()
|
|
buf = memoryview(bytearray(mlen + blklen))
|
|
f_main.render(buf)
|
|
ofs = mlen - slen
|
|
|
|
# encrypt in-place
|
|
if ciph is not None:
|
|
ciph.encryptor().update_into(buf[ofs:mlen], buf[ofs:])
|
|
|
|
return _ssh_pem_encode(buf[:mlen])
|
|
|
|
|
|
SSHPublicKeyTypes = typing.Union[
|
|
ec.EllipticCurvePublicKey,
|
|
rsa.RSAPublicKey,
|
|
dsa.DSAPublicKey,
|
|
ed25519.Ed25519PublicKey,
|
|
]
|
|
|
|
SSHCertPublicKeyTypes = typing.Union[
|
|
ec.EllipticCurvePublicKey,
|
|
rsa.RSAPublicKey,
|
|
ed25519.Ed25519PublicKey,
|
|
]
|
|
|
|
|
|
class SSHCertificateType(enum.Enum):
|
|
USER = 1
|
|
HOST = 2
|
|
|
|
|
|
class SSHCertificate:
|
|
def __init__(
|
|
self,
|
|
_nonce: memoryview,
|
|
_public_key: SSHPublicKeyTypes,
|
|
_serial: int,
|
|
_cctype: int,
|
|
_key_id: memoryview,
|
|
_valid_principals: list[bytes],
|
|
_valid_after: int,
|
|
_valid_before: int,
|
|
_critical_options: dict[bytes, bytes],
|
|
_extensions: dict[bytes, bytes],
|
|
_sig_type: memoryview,
|
|
_sig_key: memoryview,
|
|
_inner_sig_type: memoryview,
|
|
_signature: memoryview,
|
|
_tbs_cert_body: memoryview,
|
|
_cert_key_type: bytes,
|
|
_cert_body: memoryview,
|
|
):
|
|
self._nonce = _nonce
|
|
self._public_key = _public_key
|
|
self._serial = _serial
|
|
try:
|
|
self._type = SSHCertificateType(_cctype)
|
|
except ValueError:
|
|
raise ValueError("Invalid certificate type")
|
|
self._key_id = _key_id
|
|
self._valid_principals = _valid_principals
|
|
self._valid_after = _valid_after
|
|
self._valid_before = _valid_before
|
|
self._critical_options = _critical_options
|
|
self._extensions = _extensions
|
|
self._sig_type = _sig_type
|
|
self._sig_key = _sig_key
|
|
self._inner_sig_type = _inner_sig_type
|
|
self._signature = _signature
|
|
self._cert_key_type = _cert_key_type
|
|
self._cert_body = _cert_body
|
|
self._tbs_cert_body = _tbs_cert_body
|
|
|
|
@property
|
|
def nonce(self) -> bytes:
|
|
return bytes(self._nonce)
|
|
|
|
def public_key(self) -> SSHCertPublicKeyTypes:
|
|
# make mypy happy until we remove DSA support entirely and
|
|
# the underlying union won't have a disallowed type
|
|
return typing.cast(SSHCertPublicKeyTypes, self._public_key)
|
|
|
|
@property
|
|
def serial(self) -> int:
|
|
return self._serial
|
|
|
|
@property
|
|
def type(self) -> SSHCertificateType:
|
|
return self._type
|
|
|
|
@property
|
|
def key_id(self) -> bytes:
|
|
return bytes(self._key_id)
|
|
|
|
@property
|
|
def valid_principals(self) -> list[bytes]:
|
|
return self._valid_principals
|
|
|
|
@property
|
|
def valid_before(self) -> int:
|
|
return self._valid_before
|
|
|
|
@property
|
|
def valid_after(self) -> int:
|
|
return self._valid_after
|
|
|
|
@property
|
|
def critical_options(self) -> dict[bytes, bytes]:
|
|
return self._critical_options
|
|
|
|
@property
|
|
def extensions(self) -> dict[bytes, bytes]:
|
|
return self._extensions
|
|
|
|
def signature_key(self) -> SSHCertPublicKeyTypes:
|
|
sigformat = _lookup_kformat(self._sig_type)
|
|
signature_key, sigkey_rest = sigformat.load_public(self._sig_key)
|
|
_check_empty(sigkey_rest)
|
|
return signature_key
|
|
|
|
def public_bytes(self) -> bytes:
|
|
return (
|
|
bytes(self._cert_key_type)
|
|
+ b" "
|
|
+ binascii.b2a_base64(bytes(self._cert_body), newline=False)
|
|
)
|
|
|
|
def verify_cert_signature(self) -> None:
|
|
signature_key = self.signature_key()
|
|
if isinstance(signature_key, ed25519.Ed25519PublicKey):
|
|
signature_key.verify(
|
|
bytes(self._signature), bytes(self._tbs_cert_body)
|
|
)
|
|
elif isinstance(signature_key, ec.EllipticCurvePublicKey):
|
|
# The signature is encoded as a pair of big-endian integers
|
|
r, data = _get_mpint(self._signature)
|
|
s, data = _get_mpint(data)
|
|
_check_empty(data)
|
|
computed_sig = asym_utils.encode_dss_signature(r, s)
|
|
hash_alg = _get_ec_hash_alg(signature_key.curve)
|
|
signature_key.verify(
|
|
computed_sig, bytes(self._tbs_cert_body), ec.ECDSA(hash_alg)
|
|
)
|
|
else:
|
|
assert isinstance(signature_key, rsa.RSAPublicKey)
|
|
if self._inner_sig_type == _SSH_RSA:
|
|
hash_alg = hashes.SHA1()
|
|
elif self._inner_sig_type == _SSH_RSA_SHA256:
|
|
hash_alg = hashes.SHA256()
|
|
else:
|
|
assert self._inner_sig_type == _SSH_RSA_SHA512
|
|
hash_alg = hashes.SHA512()
|
|
signature_key.verify(
|
|
bytes(self._signature),
|
|
bytes(self._tbs_cert_body),
|
|
padding.PKCS1v15(),
|
|
hash_alg,
|
|
)
|
|
|
|
|
|
def _get_ec_hash_alg(curve: ec.EllipticCurve) -> hashes.HashAlgorithm:
|
|
if isinstance(curve, ec.SECP256R1):
|
|
return hashes.SHA256()
|
|
elif isinstance(curve, ec.SECP384R1):
|
|
return hashes.SHA384()
|
|
else:
|
|
assert isinstance(curve, ec.SECP521R1)
|
|
return hashes.SHA512()
|
|
|
|
|
|
def _load_ssh_public_identity(
|
|
data: bytes,
|
|
_legacy_dsa_allowed=False,
|
|
) -> SSHCertificate | SSHPublicKeyTypes:
|
|
utils._check_byteslike("data", data)
|
|
|
|
m = _SSH_PUBKEY_RC.match(data)
|
|
if not m:
|
|
raise ValueError("Invalid line format")
|
|
key_type = orig_key_type = m.group(1)
|
|
key_body = m.group(2)
|
|
with_cert = False
|
|
if key_type.endswith(_CERT_SUFFIX):
|
|
with_cert = True
|
|
key_type = key_type[: -len(_CERT_SUFFIX)]
|
|
if key_type == _SSH_DSA and not _legacy_dsa_allowed:
|
|
raise UnsupportedAlgorithm(
|
|
"DSA keys aren't supported in SSH certificates"
|
|
)
|
|
kformat = _lookup_kformat(key_type)
|
|
|
|
try:
|
|
rest = memoryview(binascii.a2b_base64(key_body))
|
|
except (TypeError, binascii.Error):
|
|
raise ValueError("Invalid format")
|
|
|
|
if with_cert:
|
|
cert_body = rest
|
|
inner_key_type, rest = _get_sshstr(rest)
|
|
if inner_key_type != orig_key_type:
|
|
raise ValueError("Invalid key format")
|
|
if with_cert:
|
|
nonce, rest = _get_sshstr(rest)
|
|
public_key, rest = kformat.load_public(rest)
|
|
if with_cert:
|
|
serial, rest = _get_u64(rest)
|
|
cctype, rest = _get_u32(rest)
|
|
key_id, rest = _get_sshstr(rest)
|
|
principals, rest = _get_sshstr(rest)
|
|
valid_principals = []
|
|
while principals:
|
|
principal, principals = _get_sshstr(principals)
|
|
valid_principals.append(bytes(principal))
|
|
valid_after, rest = _get_u64(rest)
|
|
valid_before, rest = _get_u64(rest)
|
|
crit_options, rest = _get_sshstr(rest)
|
|
critical_options = _parse_exts_opts(crit_options)
|
|
exts, rest = _get_sshstr(rest)
|
|
extensions = _parse_exts_opts(exts)
|
|
# Get the reserved field, which is unused.
|
|
_, rest = _get_sshstr(rest)
|
|
sig_key_raw, rest = _get_sshstr(rest)
|
|
sig_type, sig_key = _get_sshstr(sig_key_raw)
|
|
if sig_type == _SSH_DSA and not _legacy_dsa_allowed:
|
|
raise UnsupportedAlgorithm(
|
|
"DSA signatures aren't supported in SSH certificates"
|
|
)
|
|
# Get the entire cert body and subtract the signature
|
|
tbs_cert_body = cert_body[: -len(rest)]
|
|
signature_raw, rest = _get_sshstr(rest)
|
|
_check_empty(rest)
|
|
inner_sig_type, sig_rest = _get_sshstr(signature_raw)
|
|
# RSA certs can have multiple algorithm types
|
|
if (
|
|
sig_type == _SSH_RSA
|
|
and inner_sig_type
|
|
not in [_SSH_RSA_SHA256, _SSH_RSA_SHA512, _SSH_RSA]
|
|
) or (sig_type != _SSH_RSA and inner_sig_type != sig_type):
|
|
raise ValueError("Signature key type does not match")
|
|
signature, sig_rest = _get_sshstr(sig_rest)
|
|
_check_empty(sig_rest)
|
|
return SSHCertificate(
|
|
nonce,
|
|
public_key,
|
|
serial,
|
|
cctype,
|
|
key_id,
|
|
valid_principals,
|
|
valid_after,
|
|
valid_before,
|
|
critical_options,
|
|
extensions,
|
|
sig_type,
|
|
sig_key,
|
|
inner_sig_type,
|
|
signature,
|
|
tbs_cert_body,
|
|
orig_key_type,
|
|
cert_body,
|
|
)
|
|
else:
|
|
_check_empty(rest)
|
|
return public_key
|
|
|
|
|
|
def load_ssh_public_identity(
|
|
data: bytes,
|
|
) -> SSHCertificate | SSHPublicKeyTypes:
|
|
return _load_ssh_public_identity(data)
|
|
|
|
|
|
def _parse_exts_opts(exts_opts: memoryview) -> dict[bytes, bytes]:
|
|
result: dict[bytes, bytes] = {}
|
|
last_name = None
|
|
while exts_opts:
|
|
name, exts_opts = _get_sshstr(exts_opts)
|
|
bname: bytes = bytes(name)
|
|
if bname in result:
|
|
raise ValueError("Duplicate name")
|
|
if last_name is not None and bname < last_name:
|
|
raise ValueError("Fields not lexically sorted")
|
|
value, exts_opts = _get_sshstr(exts_opts)
|
|
if len(value) > 0:
|
|
value, extra = _get_sshstr(value)
|
|
if len(extra) > 0:
|
|
raise ValueError("Unexpected extra data after value")
|
|
result[bname] = bytes(value)
|
|
last_name = bname
|
|
return result
|
|
|
|
|
|
def load_ssh_public_key(
|
|
data: bytes, backend: typing.Any = None
|
|
) -> SSHPublicKeyTypes:
|
|
cert_or_key = _load_ssh_public_identity(data, _legacy_dsa_allowed=True)
|
|
public_key: SSHPublicKeyTypes
|
|
if isinstance(cert_or_key, SSHCertificate):
|
|
public_key = cert_or_key.public_key()
|
|
else:
|
|
public_key = cert_or_key
|
|
|
|
if isinstance(public_key, dsa.DSAPublicKey):
|
|
warnings.warn(
|
|
"SSH DSA keys are deprecated and will be removed in a future "
|
|
"release.",
|
|
utils.DeprecatedIn40,
|
|
stacklevel=2,
|
|
)
|
|
return public_key
|
|
|
|
|
|
def serialize_ssh_public_key(public_key: SSHPublicKeyTypes) -> bytes:
|
|
"""One-line public key format for OpenSSH"""
|
|
if isinstance(public_key, dsa.DSAPublicKey):
|
|
warnings.warn(
|
|
"SSH DSA key support is deprecated and will be "
|
|
"removed in a future release",
|
|
utils.DeprecatedIn40,
|
|
stacklevel=4,
|
|
)
|
|
key_type = _get_ssh_key_type(public_key)
|
|
kformat = _lookup_kformat(key_type)
|
|
|
|
f_pub = _FragList()
|
|
f_pub.put_sshstr(key_type)
|
|
kformat.encode_public(public_key, f_pub)
|
|
|
|
pub = binascii.b2a_base64(f_pub.tobytes()).strip()
|
|
return b"".join([key_type, b" ", pub])
|
|
|
|
|
|
SSHCertPrivateKeyTypes = typing.Union[
|
|
ec.EllipticCurvePrivateKey,
|
|
rsa.RSAPrivateKey,
|
|
ed25519.Ed25519PrivateKey,
|
|
]
|
|
|
|
|
|
# This is an undocumented limit enforced in the openssh codebase for sshd and
|
|
# ssh-keygen, but it is undefined in the ssh certificates spec.
|
|
_SSHKEY_CERT_MAX_PRINCIPALS = 256
|
|
|
|
|
|
class SSHCertificateBuilder:
|
|
def __init__(
|
|
self,
|
|
_public_key: SSHCertPublicKeyTypes | None = None,
|
|
_serial: int | None = None,
|
|
_type: SSHCertificateType | None = None,
|
|
_key_id: bytes | None = None,
|
|
_valid_principals: list[bytes] = [],
|
|
_valid_for_all_principals: bool = False,
|
|
_valid_before: int | None = None,
|
|
_valid_after: int | None = None,
|
|
_critical_options: list[tuple[bytes, bytes]] = [],
|
|
_extensions: list[tuple[bytes, bytes]] = [],
|
|
):
|
|
self._public_key = _public_key
|
|
self._serial = _serial
|
|
self._type = _type
|
|
self._key_id = _key_id
|
|
self._valid_principals = _valid_principals
|
|
self._valid_for_all_principals = _valid_for_all_principals
|
|
self._valid_before = _valid_before
|
|
self._valid_after = _valid_after
|
|
self._critical_options = _critical_options
|
|
self._extensions = _extensions
|
|
|
|
def public_key(
|
|
self, public_key: SSHCertPublicKeyTypes
|
|
) -> SSHCertificateBuilder:
|
|
if not isinstance(
|
|
public_key,
|
|
(
|
|
ec.EllipticCurvePublicKey,
|
|
rsa.RSAPublicKey,
|
|
ed25519.Ed25519PublicKey,
|
|
),
|
|
):
|
|
raise TypeError("Unsupported key type")
|
|
if self._public_key is not None:
|
|
raise ValueError("public_key already set")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def serial(self, serial: int) -> SSHCertificateBuilder:
|
|
if not isinstance(serial, int):
|
|
raise TypeError("serial must be an integer")
|
|
if not 0 <= serial < 2**64:
|
|
raise ValueError("serial must be between 0 and 2**64")
|
|
if self._serial is not None:
|
|
raise ValueError("serial already set")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def type(self, type: SSHCertificateType) -> SSHCertificateBuilder:
|
|
if not isinstance(type, SSHCertificateType):
|
|
raise TypeError("type must be an SSHCertificateType")
|
|
if self._type is not None:
|
|
raise ValueError("type already set")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def key_id(self, key_id: bytes) -> SSHCertificateBuilder:
|
|
if not isinstance(key_id, bytes):
|
|
raise TypeError("key_id must be bytes")
|
|
if self._key_id is not None:
|
|
raise ValueError("key_id already set")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def valid_principals(
|
|
self, valid_principals: list[bytes]
|
|
) -> SSHCertificateBuilder:
|
|
if self._valid_for_all_principals:
|
|
raise ValueError(
|
|
"Principals can't be set because the cert is valid "
|
|
"for all principals"
|
|
)
|
|
if (
|
|
not all(isinstance(x, bytes) for x in valid_principals)
|
|
or not valid_principals
|
|
):
|
|
raise TypeError(
|
|
"principals must be a list of bytes and can't be empty"
|
|
)
|
|
if self._valid_principals:
|
|
raise ValueError("valid_principals already set")
|
|
|
|
if len(valid_principals) > _SSHKEY_CERT_MAX_PRINCIPALS:
|
|
raise ValueError(
|
|
"Reached or exceeded the maximum number of valid_principals"
|
|
)
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def valid_for_all_principals(self):
|
|
if self._valid_principals:
|
|
raise ValueError(
|
|
"valid_principals already set, can't set "
|
|
"valid_for_all_principals"
|
|
)
|
|
if self._valid_for_all_principals:
|
|
raise ValueError("valid_for_all_principals already set")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=True,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def valid_before(self, valid_before: int | float) -> SSHCertificateBuilder:
|
|
if not isinstance(valid_before, (int, float)):
|
|
raise TypeError("valid_before must be an int or float")
|
|
valid_before = int(valid_before)
|
|
if valid_before < 0 or valid_before >= 2**64:
|
|
raise ValueError("valid_before must [0, 2**64)")
|
|
if self._valid_before is not None:
|
|
raise ValueError("valid_before already set")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def valid_after(self, valid_after: int | float) -> SSHCertificateBuilder:
|
|
if not isinstance(valid_after, (int, float)):
|
|
raise TypeError("valid_after must be an int or float")
|
|
valid_after = int(valid_after)
|
|
if valid_after < 0 or valid_after >= 2**64:
|
|
raise ValueError("valid_after must [0, 2**64)")
|
|
if self._valid_after is not None:
|
|
raise ValueError("valid_after already set")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def add_critical_option(
|
|
self, name: bytes, value: bytes
|
|
) -> SSHCertificateBuilder:
|
|
if not isinstance(name, bytes) or not isinstance(value, bytes):
|
|
raise TypeError("name and value must be bytes")
|
|
# This is O(n**2)
|
|
if name in [name for name, _ in self._critical_options]:
|
|
raise ValueError("Duplicate critical option name")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=[*self._critical_options, (name, value)],
|
|
_extensions=self._extensions,
|
|
)
|
|
|
|
def add_extension(
|
|
self, name: bytes, value: bytes
|
|
) -> SSHCertificateBuilder:
|
|
if not isinstance(name, bytes) or not isinstance(value, bytes):
|
|
raise TypeError("name and value must be bytes")
|
|
# This is O(n**2)
|
|
if name in [name for name, _ in self._extensions]:
|
|
raise ValueError("Duplicate extension name")
|
|
|
|
return SSHCertificateBuilder(
|
|
_public_key=self._public_key,
|
|
_serial=self._serial,
|
|
_type=self._type,
|
|
_key_id=self._key_id,
|
|
_valid_principals=self._valid_principals,
|
|
_valid_for_all_principals=self._valid_for_all_principals,
|
|
_valid_before=self._valid_before,
|
|
_valid_after=self._valid_after,
|
|
_critical_options=self._critical_options,
|
|
_extensions=[*self._extensions, (name, value)],
|
|
)
|
|
|
|
def sign(self, private_key: SSHCertPrivateKeyTypes) -> SSHCertificate:
|
|
if not isinstance(
|
|
private_key,
|
|
(
|
|
ec.EllipticCurvePrivateKey,
|
|
rsa.RSAPrivateKey,
|
|
ed25519.Ed25519PrivateKey,
|
|
),
|
|
):
|
|
raise TypeError("Unsupported private key type")
|
|
|
|
if self._public_key is None:
|
|
raise ValueError("public_key must be set")
|
|
|
|
# Not required
|
|
serial = 0 if self._serial is None else self._serial
|
|
|
|
if self._type is None:
|
|
raise ValueError("type must be set")
|
|
|
|
# Not required
|
|
key_id = b"" if self._key_id is None else self._key_id
|
|
|
|
# A zero length list is valid, but means the certificate
|
|
# is valid for any principal of the specified type. We require
|
|
# the user to explicitly set valid_for_all_principals to get
|
|
# that behavior.
|
|
if not self._valid_principals and not self._valid_for_all_principals:
|
|
raise ValueError(
|
|
"valid_principals must be set if valid_for_all_principals "
|
|
"is False"
|
|
)
|
|
|
|
if self._valid_before is None:
|
|
raise ValueError("valid_before must be set")
|
|
|
|
if self._valid_after is None:
|
|
raise ValueError("valid_after must be set")
|
|
|
|
if self._valid_after > self._valid_before:
|
|
raise ValueError("valid_after must be earlier than valid_before")
|
|
|
|
# lexically sort our byte strings
|
|
self._critical_options.sort(key=lambda x: x[0])
|
|
self._extensions.sort(key=lambda x: x[0])
|
|
|
|
key_type = _get_ssh_key_type(self._public_key)
|
|
cert_prefix = key_type + _CERT_SUFFIX
|
|
|
|
# Marshal the bytes to be signed
|
|
nonce = os.urandom(32)
|
|
kformat = _lookup_kformat(key_type)
|
|
f = _FragList()
|
|
f.put_sshstr(cert_prefix)
|
|
f.put_sshstr(nonce)
|
|
kformat.encode_public(self._public_key, f)
|
|
f.put_u64(serial)
|
|
f.put_u32(self._type.value)
|
|
f.put_sshstr(key_id)
|
|
fprincipals = _FragList()
|
|
for p in self._valid_principals:
|
|
fprincipals.put_sshstr(p)
|
|
f.put_sshstr(fprincipals.tobytes())
|
|
f.put_u64(self._valid_after)
|
|
f.put_u64(self._valid_before)
|
|
fcrit = _FragList()
|
|
for name, value in self._critical_options:
|
|
fcrit.put_sshstr(name)
|
|
if len(value) > 0:
|
|
foptval = _FragList()
|
|
foptval.put_sshstr(value)
|
|
fcrit.put_sshstr(foptval.tobytes())
|
|
else:
|
|
fcrit.put_sshstr(value)
|
|
f.put_sshstr(fcrit.tobytes())
|
|
fext = _FragList()
|
|
for name, value in self._extensions:
|
|
fext.put_sshstr(name)
|
|
if len(value) > 0:
|
|
fextval = _FragList()
|
|
fextval.put_sshstr(value)
|
|
fext.put_sshstr(fextval.tobytes())
|
|
else:
|
|
fext.put_sshstr(value)
|
|
f.put_sshstr(fext.tobytes())
|
|
f.put_sshstr(b"") # RESERVED FIELD
|
|
# encode CA public key
|
|
ca_type = _get_ssh_key_type(private_key)
|
|
caformat = _lookup_kformat(ca_type)
|
|
caf = _FragList()
|
|
caf.put_sshstr(ca_type)
|
|
caformat.encode_public(private_key.public_key(), caf)
|
|
f.put_sshstr(caf.tobytes())
|
|
# Sigs according to the rules defined for the CA's public key
|
|
# (RFC4253 section 6.6 for ssh-rsa, RFC5656 for ECDSA,
|
|
# and RFC8032 for Ed25519).
|
|
if isinstance(private_key, ed25519.Ed25519PrivateKey):
|
|
signature = private_key.sign(f.tobytes())
|
|
fsig = _FragList()
|
|
fsig.put_sshstr(ca_type)
|
|
fsig.put_sshstr(signature)
|
|
f.put_sshstr(fsig.tobytes())
|
|
elif isinstance(private_key, ec.EllipticCurvePrivateKey):
|
|
hash_alg = _get_ec_hash_alg(private_key.curve)
|
|
signature = private_key.sign(f.tobytes(), ec.ECDSA(hash_alg))
|
|
r, s = asym_utils.decode_dss_signature(signature)
|
|
fsig = _FragList()
|
|
fsig.put_sshstr(ca_type)
|
|
fsigblob = _FragList()
|
|
fsigblob.put_mpint(r)
|
|
fsigblob.put_mpint(s)
|
|
fsig.put_sshstr(fsigblob.tobytes())
|
|
f.put_sshstr(fsig.tobytes())
|
|
|
|
else:
|
|
assert isinstance(private_key, rsa.RSAPrivateKey)
|
|
# Just like Golang, we're going to use SHA512 for RSA
|
|
# https://cs.opensource.google/go/x/crypto/+/refs/tags/
|
|
# v0.4.0:ssh/certs.go;l=445
|
|
# RFC 8332 defines SHA256 and 512 as options
|
|
fsig = _FragList()
|
|
fsig.put_sshstr(_SSH_RSA_SHA512)
|
|
signature = private_key.sign(
|
|
f.tobytes(), padding.PKCS1v15(), hashes.SHA512()
|
|
)
|
|
fsig.put_sshstr(signature)
|
|
f.put_sshstr(fsig.tobytes())
|
|
|
|
cert_data = binascii.b2a_base64(f.tobytes()).strip()
|
|
# load_ssh_public_identity returns a union, but this is
|
|
# guaranteed to be an SSHCertificate, so we cast to make
|
|
# mypy happy.
|
|
return typing.cast(
|
|
SSHCertificate,
|
|
load_ssh_public_identity(b"".join([cert_prefix, b" ", cert_data])),
|
|
)
|