Merge pull request #81 from Kriechi/protocol-refactor

HTTP protocol refactoring

1 files changed, 169 insertions, 0 deletions

diff --git a/netlib/http/authentication.py b/netlib/http/authentication.py
new file mode 100644
index 00000000..9a227010
--- /dev/null
+++ b/netlib/http/authentication.py
@@ -0,0 +1,169 @@
+from __future__ import (absolute_import, print_function, division)
+from argparse import Action, ArgumentTypeError
+import binascii
+
+from .. import http
+
+def parse_http_basic_auth(s):
+    words = s.split()
+    if len(words) != 2:
+        return None
+    scheme = words[0]
+    try:
+        user = binascii.a2b_base64(words[1])
+    except binascii.Error:
+        return None
+    parts = user.split(':')
+    if len(parts) != 2:
+        return None
+    return scheme, parts[0], parts[1]
+
+
+def assemble_http_basic_auth(scheme, username, password):
+    v = binascii.b2a_base64(username + ":" + password)
+    return scheme + " " + v
+
+
+class NullProxyAuth(object):
+
+    """
+        No proxy auth at all (returns empty challange headers)
+    """
+
+    def __init__(self, password_manager):
+        self.password_manager = password_manager
+
+    def clean(self, headers_):
+        """
+            Clean up authentication headers, so they're not passed upstream.
+        """
+        pass
+
+    def authenticate(self, headers_):
+        """
+            Tests that the user is allowed to use the proxy
+        """
+        return True
+
+    def auth_challenge_headers(self):
+        """
+            Returns a dictionary containing the headers require to challenge the user
+        """
+        return {}
+
+
+class BasicProxyAuth(NullProxyAuth):
+    CHALLENGE_HEADER = 'Proxy-Authenticate'
+    AUTH_HEADER = 'Proxy-Authorization'
+
+    def __init__(self, password_manager, realm):
+        NullProxyAuth.__init__(self, password_manager)
+        self.realm = realm
+
+    def clean(self, headers):
+        del headers[self.AUTH_HEADER]
+
+    def authenticate(self, headers):
+        auth_value = headers.get(self.AUTH_HEADER, [])
+        if not auth_value:
+            return False
+        parts = parse_http_basic_auth(auth_value[0])
+        if not parts:
+            return False
+        scheme, username, password = parts
+        if scheme.lower() != 'basic':
+            return False
+        if not self.password_manager.test(username, password):
+            return False
+        self.username = username
+        return True
+
+    def auth_challenge_headers(self):
+        return {self.CHALLENGE_HEADER: 'Basic realm="%s"' % self.realm}
+
+
+class PassMan(object):
+
+    def test(self, username_, password_token_):
+        return False
+
+
+class PassManNonAnon(PassMan):
+
+    """
+        Ensure the user specifies a username, accept any password.
+    """
+
+    def test(self, username, password_token_):
+        if username:
+            return True
+        return False
+
+
+class PassManHtpasswd(PassMan):
+
+    """
+        Read usernames and passwords from an htpasswd file
+    """
+
+    def __init__(self, path):
+        """
+            Raises ValueError if htpasswd file is invalid.
+        """
+        import passlib.apache
+        self.htpasswd = passlib.apache.HtpasswdFile(path)
+
+    def test(self, username, password_token):
+        return bool(self.htpasswd.check_password(username, password_token))
+
+
+class PassManSingleUser(PassMan):
+
+    def __init__(self, username, password):
+        self.username, self.password = username, password
+
+    def test(self, username, password_token):
+        return self.username == username and self.password == password_token
+
+
+class AuthAction(Action):
+
+    """
+    Helper class to allow seamless integration int argparse. Example usage:
+    parser.add_argument(
+        "--nonanonymous",
+        action=NonanonymousAuthAction, nargs=0,
+        help="Allow access to any user long as a credentials are specified."
+    )
+    """
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        passman = self.getPasswordManager(values)
+        authenticator = BasicProxyAuth(passman, "mitmproxy")
+        setattr(namespace, self.dest, authenticator)
+
+    def getPasswordManager(self, s):  # pragma: nocover
+        raise NotImplementedError()
+
+
+class SingleuserAuthAction(AuthAction):
+
+    def getPasswordManager(self, s):
+        if len(s.split(':')) != 2:
+            raise ArgumentTypeError(
+                "Invalid single-user specification. Please use the format username:password"
+            )
+        username, password = s.split(':')
+        return PassManSingleUser(username, password)
+
+
+class NonanonymousAuthAction(AuthAction):
+
+    def getPasswordManager(self, s):
+        return PassManNonAnon()
+
+
+class HtpasswdAuthAction(AuthAction):
+
+    def getPasswordManager(self, s):
+        return PassManHtpasswd(s)