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"""
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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