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Editing: _auth.py
""" Implements auth methods """ from .err import OperationalError try: from cryptography.hazmat.backends import default_backend from cryptography.hazmat.primitives import serialization, hashes from cryptography.hazmat.primitives.asymmetric import padding _have_cryptography = True except ImportError: _have_cryptography = False from functools import partial import hashlib DEBUG = False SCRAMBLE_LENGTH = 20 sha1_new = partial(hashlib.new, "sha1") # mysql_native_password # https://dev.mysql.com/doc/internals/en/secure-password-authentication.html#packet-Authentication::Native41 def scramble_native_password(password, message): """Scramble used for mysql_native_password""" if not password: return b"" stage1 = sha1_new(password).digest() stage2 = sha1_new(stage1).digest() s = sha1_new() s.update(message[:SCRAMBLE_LENGTH]) s.update(stage2) result = s.digest() return _my_crypt(result, stage1) def _my_crypt(message1, message2): result = bytearray(message1) for i in range(len(result)): result[i] ^= message2[i] return bytes(result) # MariaDB's client_ed25519-plugin # https://mariadb.com/kb/en/library/connection/#client_ed25519-plugin _nacl_bindings = False def _init_nacl(): global _nacl_bindings try: from nacl import bindings _nacl_bindings = bindings except ImportError: raise RuntimeError( "'pynacl' package is required for ed25519_password auth method" ) def _scalar_clamp(s32): ba = bytearray(s32) ba0 = bytes(bytearray([ba[0] & 248])) ba31 = bytes(bytearray([(ba[31] & 127) | 64])) return ba0 + bytes(s32[1:31]) + ba31 def ed25519_password(password, scramble): """Sign a random scramble with elliptic curve Ed25519. Secret and public key are derived from password. """ # variable names based on rfc8032 section-5.1.6 # if not _nacl_bindings: _init_nacl() # h = SHA512(password) h = hashlib.sha512(password).digest() # s = prune(first_half(h)) s = _scalar_clamp(h[:32]) # r = SHA512(second_half(h) || M) r = hashlib.sha512(h[32:] + scramble).digest() # R = encoded point [r]B r = _nacl_bindings.crypto_core_ed25519_scalar_reduce(r) R = _nacl_bindings.crypto_scalarmult_ed25519_base_noclamp(r) # A = encoded point [s]B A = _nacl_bindings.crypto_scalarmult_ed25519_base_noclamp(s) # k = SHA512(R || A || M) k = hashlib.sha512(R + A + scramble).digest() # S = (k * s + r) mod L k = _nacl_bindings.crypto_core_ed25519_scalar_reduce(k) ks = _nacl_bindings.crypto_core_ed25519_scalar_mul(k, s) S = _nacl_bindings.crypto_core_ed25519_scalar_add(ks, r) # signature = R || S return R + S # sha256_password def _roundtrip(conn, send_data): conn.write_packet(send_data) pkt = conn._read_packet() pkt.check_error() return pkt def _xor_password(password, salt): # Trailing NUL character will be added in Auth Switch Request. # See https://github.com/mysql/mysql-server/blob/7d10c82196c8e45554f27c00681474a9fb86d137/sql/auth/sha2_password.cc#L939-L945 salt = salt[:SCRAMBLE_LENGTH] password_bytes = bytearray(password) # salt = bytearray(salt) # for PY2 compat. salt_len = len(salt) for i in range(len(password_bytes)): password_bytes[i] ^= salt[i % salt_len] return bytes(password_bytes) def sha2_rsa_encrypt(password, salt, public_key): """Encrypt password with salt and public_key. Used for sha256_password and caching_sha2_password. """ if not _have_cryptography: raise RuntimeError( "'cryptography' package is required for sha256_password or" + " caching_sha2_password auth methods" ) message = _xor_password(password + b"\0", salt) rsa_key = serialization.load_pem_public_key(public_key, default_backend()) return rsa_key.encrypt( message, padding.OAEP( mgf=padding.MGF1(algorithm=hashes.SHA1()), algorithm=hashes.SHA1(), label=None, ), ) def sha256_password_auth(conn, pkt): if conn._secure: if DEBUG: print("sha256: Sending plain password") data = conn.password + b"\0" return _roundtrip(conn, data) if pkt.is_auth_switch_request(): conn.salt = pkt.read_all() if not conn.server_public_key and conn.password: # Request server public key if DEBUG: print("sha256: Requesting server public key") pkt = _roundtrip(conn, b"\1") if pkt.is_extra_auth_data(): conn.server_public_key = pkt._data[1:] if DEBUG: print("Received public key:\n", conn.server_public_key.decode("ascii")) if conn.password: if not conn.server_public_key: raise OperationalError("Couldn't receive server's public key") data = sha2_rsa_encrypt(conn.password, conn.salt, conn.server_public_key) else: data = b"" return _roundtrip(conn, data) def scramble_caching_sha2(password, nonce): # (bytes, bytes) -> bytes """Scramble algorithm used in cached_sha2_password fast path. XOR(SHA256(password), SHA256(SHA256(SHA256(password)), nonce)) """ if not password: return b"" p1 = hashlib.sha256(password).digest() p2 = hashlib.sha256(p1).digest() p3 = hashlib.sha256(p2 + nonce).digest() res = bytearray(p1) for i in range(len(p3)): res[i] ^= p3[i] return bytes(res) def caching_sha2_password_auth(conn, pkt): # No password fast path if not conn.password: return _roundtrip(conn, b"") if pkt.is_auth_switch_request(): # Try from fast auth if DEBUG: print("caching sha2: Trying fast path") conn.salt = pkt.read_all() scrambled = scramble_caching_sha2(conn.password, conn.salt) pkt = _roundtrip(conn, scrambled) # else: fast auth is tried in initial handshake if not pkt.is_extra_auth_data(): raise OperationalError( "caching sha2: Unknown packet for fast auth: %s" % pkt._data[:1] ) # magic numbers: # 2 - request public key # 3 - fast auth succeeded # 4 - need full auth pkt.advance(1) n = pkt.read_uint8() if n == 3: if DEBUG: print("caching sha2: succeeded by fast path.") pkt = conn._read_packet() pkt.check_error() # pkt must be OK packet return pkt if n != 4: raise OperationalError("caching sha2: Unknown result for fast auth: %s" % n) if DEBUG: print("caching sha2: Trying full auth...") if conn._secure: if DEBUG: print("caching sha2: Sending plain password via secure connection") return _roundtrip(conn, conn.password + b"\0") if not conn.server_public_key: pkt = _roundtrip(conn, b"\x02") # Request public key if not pkt.is_extra_auth_data(): raise OperationalError( "caching sha2: Unknown packet for public key: %s" % pkt._data[:1] ) conn.server_public_key = pkt._data[1:] if DEBUG: print(conn.server_public_key.decode("ascii")) data = sha2_rsa_encrypt(conn.password, conn.salt, conn.server_public_key) pkt = _roundtrip(conn, data)
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