Source code for octomachinery.github.models.private_key

"""Private key container."""
from hashlib import sha1 as compute_sha1_hash
from pathlib import Path
from time import time

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.serialization import Encoding, PublicFormat
from cryptography.hazmat.primitives.serialization import load_pem_private_key

from ._compat import compute_jwt


[docs]def extract_private_key_sha1_fingerprint(rsa_private_key): r"""Retrieve the private key SHA-1 fingerprint. :param rsa_private_key: private key object :type rsa_private_key: cryptography.hazmat.primitives.asymmetric.\ rsa.RSAPrivateKey :returns: colon-separated SHA-1 fingerprint :rtype: str """ rsa_public_key = rsa_private_key.public_key() b_rsa_public_key = rsa_public_key.public_bytes( Encoding.DER, PublicFormat.SubjectPublicKeyInfo, ) rsa_public_key_sha1_fingerprint = compute_sha1_hash( b_rsa_public_key, ).hexdigest() def emit_chunks(sequence, step): start_pos = 0 seq_length = len(sequence) while start_pos < seq_length: end_pos = start_pos + step yield sequence[start_pos: end_pos] start_pos = end_pos return ':'.join( emit_chunks(rsa_public_key_sha1_fingerprint, 2), )
[docs]class GitHubPrivateKey: """Private key entity with a pre-calculated SHA-1 fingerprint. :param bytes b_raw_data: the contents of a PEM file """ def __init__(self, b_raw_data: bytes): """Initialize GitHubPrivateKey instance.""" self._rsa_private_key = load_pem_private_key( b_raw_data, password=None, backend=default_backend(), ) self._col_separated_rsa_public_key_sha1_fingerprint = ( extract_private_key_sha1_fingerprint(self._rsa_private_key) ) @property def fingerprint(self) -> str: """Colon-separated SHA-1 fingerprint string value. :returns: colon-separated SHA-1 fingerprint :rtype: str """ return self._col_separated_rsa_public_key_sha1_fingerprint def __str__(self): """Avoid leaking private key contents via string protocol. :raises TypeError: always """ raise TypeError( f'{type(self)} objects do not implement the string protocol ' 'for security reasons. ' f'The repr of this instance is {self!r}.', ) def __repr__(self): r"""Construct a GitHubPrivateKey object representation. :returns: GitHubPrivateKey object representation \ with its SHA-1 fingerprint :rtype: str """ return ( "<GitHubPrivateKey(b_raw_data=b'<SECRET>') " f"with SHA-1 fingerprint '{self.fingerprint}'>" ) def __eq__(self, other_private_key): r"""Compare equality of our private key with other. :returns: the result of comparison with another \ ``GitHubPrivateKey`` instance :rtype: bool """ return self.matches_fingerprint(other_private_key.fingerprint)
[docs] def matches_fingerprint(self, other_hash): """Compare our SHA-1 fingerprint with ``other_hash``. :returns: the result of own fingerprint comparison with ``other_hash`` :rtype: bool """ return self.fingerprint == other_hash
[docs] @classmethod def from_file(cls, path): r"""Construct a ``GitHubPrivateKey`` instance. :returns: the ``GitHubPrivateKey`` instance \ constructed of the target file contents :rtype: GitHubPrivateKey """ return cls(Path(path).expanduser().read_bytes())
[docs] def make_jwt_for(self, *, app_id: int, time_offset: int = 60) -> str: r"""Generate app's JSON Web Token. :param int app_id: numeric ID of a GitHub App :param int time_offset: duration of the JWT's validity, in seconds, \ defaults to 60 :returns: JWT string for a GitHub App valid for the given time :rtype: str :raises ValueError: if time_offset exceeds 600 seconds (10 minutes) """ ten_min = 60 * 10 if time_offset > ten_min: raise ValueError('The time offset must be less than 10 minutes') now = int(time()) payload = { 'iat': now, 'exp': now + time_offset, 'iss': app_id, } return compute_jwt( payload, key=self._rsa_private_key, algorithm='RS256', )