1# Authors:
2#   Trevor Perrin
3#   Dimitris Moraitis - Anon ciphersuites
4#
5# See the LICENSE file for legal information regarding use of this file.
6
7"""
8A helper class for using TLS Lite with stdlib clients
9(httplib, xmlrpclib, imaplib, poplib).
10"""
11
12from tlslite.checker import Checker
13
14class ClientHelper(object):
15    """This is a helper class used to integrate TLS Lite with various
16    TLS clients (e.g. poplib, smtplib, httplib, etc.)"""
17
18    def __init__(self,
19              username=None, password=None,
20              certChain=None, privateKey=None,
21              checker=None,
22              settings = None,
23              anon = False):
24        """
25        For client authentication, use one of these argument
26        combinations:
27         - username, password (SRP)
28         - certChain, privateKey (certificate)
29
30        For server authentication, you can either rely on the
31        implicit mutual authentication performed by SRP,
32        or you can do certificate-based server
33        authentication with one of these argument combinations:
34         - x509Fingerprint
35
36        Certificate-based server authentication is compatible with
37        SRP or certificate-based client authentication.
38
39        The constructor does not perform the TLS handshake itself, but
40        simply stores these arguments for later.  The handshake is
41        performed only when this class needs to connect with the
42        server.  Then you should be prepared to handle TLS-specific
43        exceptions.  See the client handshake functions in
44        L{tlslite.TLSConnection.TLSConnection} for details on which
45        exceptions might be raised.
46
47        @type username: str
48        @param username: SRP username.  Requires the
49        'password' argument.
50
51        @type password: str
52        @param password: SRP password for mutual authentication.
53        Requires the 'username' argument.
54
55        @type certChain: L{tlslite.x509certchain.X509CertChain}
56        @param certChain: Certificate chain for client authentication.
57        Requires the 'privateKey' argument.  Excludes the SRP arguments.
58
59        @type privateKey: L{tlslite.utils.rsakey.RSAKey}
60        @param privateKey: Private key for client authentication.
61        Requires the 'certChain' argument.  Excludes the SRP arguments.
62
63        @type checker: L{tlslite.checker.Checker}
64        @param checker: Callable object called after handshaking to
65        evaluate the connection and raise an Exception if necessary.
66
67        @type settings: L{tlslite.handshakesettings.HandshakeSettings}
68        @param settings: Various settings which can be used to control
69        the ciphersuites, certificate types, and SSL/TLS versions
70        offered by the client.
71        """
72
73        self.username = None
74        self.password = None
75        self.certChain = None
76        self.privateKey = None
77        self.checker = None
78        self.anon = anon
79
80        #SRP Authentication
81        if username and password and not \
82                (certChain or privateKey):
83            self.username = username
84            self.password = password
85
86        #Certificate Chain Authentication
87        elif certChain and privateKey and not \
88                (username or password):
89            self.certChain = certChain
90            self.privateKey = privateKey
91
92        #No Authentication
93        elif not password and not username and not \
94                certChain and not privateKey:
95            pass
96
97        else:
98            raise ValueError("Bad parameters")
99
100        self.checker = checker
101        self.settings = settings
102
103        self.tlsSession = None
104
105    def _handshake(self, tlsConnection):
106        if self.username and self.password:
107            tlsConnection.handshakeClientSRP(username=self.username,
108                                             password=self.password,
109                                             checker=self.checker,
110                                             settings=self.settings,
111                                             session=self.tlsSession)
112        elif self.anon:
113            tlsConnection.handshakeClientAnonymous(session=self.tlsSession,
114                                                settings=self.settings,
115                                                checker=self.checker)
116        else:
117            tlsConnection.handshakeClientCert(certChain=self.certChain,
118                                              privateKey=self.privateKey,
119                                              checker=self.checker,
120                                              settings=self.settings,
121                                              session=self.tlsSession)
122        self.tlsSession = tlsConnection.session