Merge branch 'support_old_hash' into 'dev'

Support old hashes, md5/crypt

See merge request federez/re2o!215

re2o/login.py

@@ -28,14 +28,14 @@
 Module in charge of handling the login process and verifications
 """
 
-import hashlib
 import binascii
+import crypt
+import hashlib
 import os
-from base64 import encodestring
-from base64 import decodestring
+from base64 import encodestring, decodestring, b64encode, b64decode
 from collections import OrderedDict
-
 from django.contrib.auth import hashers
+from hmac import compare_digest as constant_time_compare
 
 
 ALGO_NAME = "{SSHA}"
@@ -64,17 +64,127 @@ def checkPassword(challenge_password, password):
     salt = challenge_bytes[DIGEST_LEN:]
     hr = hashlib.sha1(password.encode())
     hr.update(salt)
-    valid_password = True
-    # La comparaison est volontairement en temps constant
-    # (pour éviter les timing-attacks)
-    for i, j in zip(digest, hr.digest()):
-        valid_password &= i == j
-    return valid_password
+    return constant_time_compare(digest, hr.digest())
 
 
+def hash_password_salt(hashed_password):
+    """ Extract the salt from a given hashed password """
+    if hashed_password.upper().startswith('{CRYPT}'):
+        hashed_password = hashed_password[7:]
+        if hashed_password.startswith('$'):
+            return '$'.join(hashed_password.split('$')[:-1])
+        else:
+            return hashed_password[:2]
+    elif hashed_password.upper().startswith('{SSHA}'):
+        try:
+            digest = b64decode(hashed_password[6:])
+        except TypeError as error:
+            raise ValueError("b64 error for `hashed_password` : %s" % error)
+        if len(digest) < 20:
+            raise ValueError("`hashed_password` too short")
+        return digest[20:]
+    elif hashed_password.upper().startswith('{SMD5}'):
+        try:
+            digest = b64decode(hashed_password[7:])
+        except TypeError as error:
+            raise ValueError("b64 error for `hashed_password` : %s" % error)
+        if len(digest) < 16:
+            raise ValueError("`hashed_password` too short")
+        return digest[16:]
+    else:
+        raise ValueError("`hashed_password` should start with '{SSHA}' or '{CRYPT}' or '{SMD5}'")
+
+
+
+class CryptPasswordHasher(hashers.BasePasswordHasher):
+    """
+    Crypt password hashing to allow for LDAP auth compatibility
+    We do not encode, this should bot be used !
+    The actual implementation may depend on the OS.
+    """
+
+    algorithm = "{crypt}"
+
+    def encode(self, password, salt):
+        pass
+
+    def verify(self, password, encoded):
+        """
+        Check password against encoded using CRYPT algorithm
+        """
+        assert encoded.startswith(self.algorithm)
+        salt = hash_password_salt(challenge_password)
+        return constant_time_compare(crypt.crypt(password.encode(), salt),
+                                     challenge.encode())
+
+    def safe_summary(self, encoded):
+        """
+        Provides a safe summary of the password
+        """
+        assert encoded.startswith(self.algorithm)
+        hash_str = encoded[7:]
+        hash_str = binascii.hexlify(decodestring(hash_str.encode())).decode()
+        return OrderedDict([
+            ('algorithm', self.algorithm),
+            ('iterations', 0),
+            ('salt', hashers.mask_hash(hash_str[2*DIGEST_LEN:], show=2)),
+            ('hash', hashers.mask_hash(hash_str[:2*DIGEST_LEN])),
+        ])
+
+    def harden_runtime(self, password, encoded):
+        """
+        Method implemented to shut up BasePasswordHasher warning
+
+        As we are not using multiple iterations the method is pretty useless
+        """
+        pass
+
+class MD5PasswordHasher(hashers.BasePasswordHasher):
+    """
+    Salted MD5 password hashing to allow for LDAP auth compatibility
+    We do not encode, this should bot be used !
+    """
+
+    algorithm = "{SMD5}"
+
+    def encode(self, password, salt):
+        pass
+
+    def verify(self, password, encoded):
+        """
+        Check password against encoded using SMD5 algorithm
+        """
+        assert encoded.startswith(self.algorithm)
+        salt = hash_password_salt(encoded)
+        return constant_time_compare(
+            b64encode(hashlib.md5(password.encode() + salt).digest() + salt),
+            encoded.encode())
+
+    def safe_summary(self, encoded):
+        """
+        Provides a safe summary of the password
+        """
+        assert encoded.startswith(self.algorithm)
+        hash_str = encoded[7:]
+        hash_str = binascii.hexlify(decodestring(hash_str.encode())).decode()
+        return OrderedDict([
+            ('algorithm', self.algorithm),
+            ('iterations', 0),
+            ('salt', hashers.mask_hash(hash_str[2*DIGEST_LEN:], show=2)),
+            ('hash', hashers.mask_hash(hash_str[:2*DIGEST_LEN])),
+        ])
+
+    def harden_runtime(self, password, encoded):
+        """
+        Method implemented to shut up BasePasswordHasher warning
+
+        As we are not using multiple iterations the method is pretty useless
+        """
+        pass
+
 class SSHAPasswordHasher(hashers.BasePasswordHasher):
     """
-    SSHA password hashing to allow for LDAP auth compatibility
+    Salted SHA-1 password hashing to allow for LDAP auth compatibility
     """
 
     algorithm = ALGO_NAME

re2o/settings.py

@@ -46,6 +46,8 @@ BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 # Auth definition
 PASSWORD_HASHERS = (
     're2o.login.SSHAPasswordHasher',
+    're2o.login.MD5PasswordHasher',
+    're2o.login.CryptPasswordHasher',
     'django.contrib.auth.hashers.PBKDF2PasswordHasher',
 )
 AUTH_USER_MODEL = 'users.User'  # The class to use for authentication

users/models.py

@@ -537,7 +537,16 @@ class User(RevMixin, FieldPermissionModelMixin, AbstractBaseUser,
             user_ldap.given_name = self.surname.lower() + '_'\
                 + self.name.lower()[:3]
             user_ldap.gid = LDAP['user_gid']
-            user_ldap.user_password = self.password[:6] + self.password[7:]
+            if '{SSHA}' in self.password or '{SMD5}' in self.password:
+                # We remove the extra $ added at import from ldap
+                user_ldap.user_password = self.password[:6] + self.password[7:]
+            elif '{crypt}' in self.password:
+                # depending on the length, we need to remove or not a $
+                if len(self.password)==41:
+                    user_ldap.user_password = self.password
+                else: 
+                    user_ldap.user_password = self.password[:7] + self.password[8:]
+
             user_ldap.sambat_nt_password = self.pwd_ntlm.upper()
             if self.get_shell:
                 user_ldap.login_shell = str(self.get_shell)