Support for MariaDB's auth_ed25519 authentication plugin (PyMySQL#786) (PyMySQL#791)

Author: dciabrin

.travis.yml

@@ -23,6 +23,7 @@ matrix:
       python: "2.7"
     - env:
         - DB=mariadb:10.3
+        - TEST_MARIADB_AUTH=yes
       python: "3.7"
     - env:
         - DB=mysql:5.5
@@ -46,7 +47,7 @@ matrix:
 # http://dev.mysql.com/downloads/mysql/5.7.html has latest development release version
 # really only need libaio1 for DB builds however libaio-dev is whitelisted for container builds and liaio1 isn't
 install:
-  - pip install -U coveralls coverage cryptography pytest pytest-cov
+  - pip install -U coveralls coverage cryptography PyNaCl pytest pytest-cov
 
 before_script:
   - ./.travis/initializedb.sh
@@ -57,7 +58,10 @@ before_script:
 script:
   - pytest -v --cov --cov-config .coveragerc pymysql
   - if [ "${TEST_AUTH}" = "yes" ];
-    then pytest -v --cov --cov-config .coveragerc tests;
+    then pytest -v --cov --cov-config .coveragerc tests/test_auth.py;
+    fi
+  - if [ "${TEST_MARIADB_AUTH}" = "yes" ];
+    then pytest -v --cov --cov-config .coveragerc tests/test_mariadb_auth.py;
     fi
   - if [ ! -z "${DB}" ];
     then docker logs mysqld;

.travis/initializedb.sh

@@ -6,7 +6,7 @@ docker pull ${DB}
 docker run -it --name=mysqld -d -e MYSQL_ALLOW_EMPTY_PASSWORD=yes -p 3306:3306 ${DB}
 
 mysql() {
-    docker exec mysqld mysql "${@}"
+    docker exec -i mysqld mysql "${@}"
 }
 while :
 do
@@ -33,6 +33,14 @@ if [ $DB == 'mysql:8.0' ]; then
             nopass_caching_sha2 IDENTIFIED WITH "caching_sha2_password"
             PASSWORD EXPIRE NEVER;'
     mysql -e 'GRANT RELOAD ON *.* TO user_caching_sha2;'
+elif [[ $DB == mariadb:10.* ]] && [ ${DB#mariadb:10.} -ge 3 ]; then
+    mysql -e '
+        INSTALL SONAME "auth_ed25519";
+        CREATE FUNCTION ed25519_password RETURNS STRING SONAME "auth_ed25519.so";'
+    # we need to pass the hashed password manually until 10.4, so hide it here
+    mysql -sNe "SELECT CONCAT('CREATE USER nopass_ed25519 IDENTIFIED VIA ed25519 USING \"',ed25519_password(\"\"),'\";');" | mysql
+    mysql -sNe "SELECT CONCAT('CREATE USER user_ed25519 IDENTIFIED VIA ed25519 USING \"',ed25519_password(\"pass_ed25519\"),'\";');" | mysql
+    WITH_PLUGIN=''
 else
     WITH_PLUGIN=''
 fi

README.rst

@@ -66,6 +66,11 @@ you need to install additional dependency::
 
    $ python3 -m pip install PyMySQL[rsa]
 
+To use MariaDB's "ed25519" authentication method, you need to install
+additional dependency::
+
+   $ python3 -m pip install PyMySQL[ed25519]
+
 
 Documentation
 -------------

pymysql/_auth.py

@@ -113,6 +113,66 @@ def _hash_password_323(password):
     return struct.pack(">LL", r1, r2)
 
 
+# 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
 
 

pymysql/connections.py

@@ -894,6 +894,8 @@ def _process_auth(self, plugin_name, auth_packet):
             return _auth.sha256_password_auth(self, auth_packet)
         elif plugin_name == b"mysql_native_password":
             data = _auth.scramble_native_password(self.password, auth_packet.read_all())
+        elif plugin_name == b'client_ed25519':
+            data = _auth.ed25519_password(self.password, auth_packet.read_all())
         elif plugin_name == b"mysql_old_password":
             data = _auth.scramble_old_password(self.password, auth_packet.read_all()) + b'\0'
         elif plugin_name == b"mysql_clear_password":

requirements-dev.txt

@@ -1,2 +1,3 @@
 cryptography
+PyNaCl>=1.4.0
 pytest

setup.py

@@ -19,6 +19,7 @@
     packages=find_packages(exclude=['tests*', 'pymysql.tests*']),
     extras_require={
         "rsa": ["cryptography"],
+        "ed25519": ["PyNaCl>=1.4.0"],
     },
     classifiers=[
         'Development Status :: 5 - Production/Stable',

tests/test_mariadb_auth.py

@@ -0,0 +1,23 @@
+"""Test for auth methods supported by MariaDB 10.3+"""
+
+import pymysql
+
+# pymysql.connections.DEBUG = True
+# pymysql._auth.DEBUG = True
+
+host = "127.0.0.1"
+port = 3306
+
+
+def test_ed25519_no_password():
+    con = pymysql.connect(user="nopass_ed25519", host=host, port=port, ssl=None)
+    con.close()
+
+
+def test_ed25519_password():  # nosec
+    con = pymysql.connect(user="user_ed25519", password="pass_ed25519",
+                          host=host, port=port, ssl=None)
+    con.close()
+
+
+# default mariadb docker images aren't configured with SSL