errors.py revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1"""Exception classes.
2@sort: TLSError, TLSAbruptCloseError, TLSAlert, TLSLocalAlert, TLSRemoteAlert,
3TLSAuthenticationError, TLSNoAuthenticationError, TLSAuthenticationTypeError,
4TLSFingerprintError, TLSAuthorizationError, TLSValidationError, TLSFaultError
5"""
6
7from constants import AlertDescription, AlertLevel
8
9class TLSError(Exception):
10    """Base class for all TLS Lite exceptions."""
11    pass
12
13class TLSAbruptCloseError(TLSError):
14    """The socket was closed without a proper TLS shutdown.
15
16    The TLS specification mandates that an alert of some sort
17    must be sent before the underlying socket is closed.  If the socket
18    is closed without this, it could signify that an attacker is trying
19    to truncate the connection.  It could also signify a misbehaving
20    TLS implementation, or a random network failure.
21    """
22    pass
23
24class TLSAlert(TLSError):
25    """A TLS alert has been signalled."""
26    pass
27
28    _descriptionStr = {\
29        AlertDescription.close_notify: "close_notify",\
30        AlertDescription.unexpected_message: "unexpected_message",\
31        AlertDescription.bad_record_mac: "bad_record_mac",\
32        AlertDescription.decryption_failed: "decryption_failed",\
33        AlertDescription.record_overflow: "record_overflow",\
34        AlertDescription.decompression_failure: "decompression_failure",\
35        AlertDescription.handshake_failure: "handshake_failure",\
36        AlertDescription.no_certificate: "no certificate",\
37        AlertDescription.bad_certificate: "bad_certificate",\
38        AlertDescription.unsupported_certificate: "unsupported_certificate",\
39        AlertDescription.certificate_revoked: "certificate_revoked",\
40        AlertDescription.certificate_expired: "certificate_expired",\
41        AlertDescription.certificate_unknown: "certificate_unknown",\
42        AlertDescription.illegal_parameter: "illegal_parameter",\
43        AlertDescription.unknown_ca: "unknown_ca",\
44        AlertDescription.access_denied: "access_denied",\
45        AlertDescription.decode_error: "decode_error",\
46        AlertDescription.decrypt_error: "decrypt_error",\
47        AlertDescription.export_restriction: "export_restriction",\
48        AlertDescription.protocol_version: "protocol_version",\
49        AlertDescription.insufficient_security: "insufficient_security",\
50        AlertDescription.internal_error: "internal_error",\
51        AlertDescription.user_canceled: "user_canceled",\
52        AlertDescription.no_renegotiation: "no_renegotiation",\
53        AlertDescription.unknown_srp_username: "unknown_srp_username",\
54        AlertDescription.missing_srp_username: "missing_srp_username"}
55
56class TLSLocalAlert(TLSAlert):
57    """A TLS alert has been signalled by the local implementation.
58
59    @type description: int
60    @ivar description: Set to one of the constants in
61    L{tlslite.constants.AlertDescription}
62
63    @type level: int
64    @ivar level: Set to one of the constants in
65    L{tlslite.constants.AlertLevel}
66
67    @type message: str
68    @ivar message: Description of what went wrong.
69    """
70    def __init__(self, alert, message=None):
71        self.description = alert.description
72        self.level = alert.level
73        self.message = message
74
75    def __str__(self):
76        alertStr = TLSAlert._descriptionStr.get(self.description)
77        if alertStr == None:
78            alertStr = str(self.description)
79        if self.message:
80            return alertStr + ": " + self.message
81        else:
82            return alertStr
83
84class TLSRemoteAlert(TLSAlert):
85    """A TLS alert has been signalled by the remote implementation.
86
87    @type description: int
88    @ivar description: Set to one of the constants in
89    L{tlslite.constants.AlertDescription}
90
91    @type level: int
92    @ivar level: Set to one of the constants in
93    L{tlslite.constants.AlertLevel}
94    """
95    def __init__(self, alert):
96        self.description = alert.description
97        self.level = alert.level
98
99    def __str__(self):
100        alertStr = TLSAlert._descriptionStr.get(self.description)
101        if alertStr == None:
102            alertStr = str(self.description)
103        return alertStr
104
105class TLSAuthenticationError(TLSError):
106    """The handshake succeeded, but the other party's authentication
107    was inadequate.
108
109    This exception will only be raised when a
110    L{tlslite.Checker.Checker} has been passed to a handshake function.
111    The Checker will be invoked once the handshake completes, and if
112    the Checker objects to how the other party authenticated, a
113    subclass of this exception will be raised.
114    """
115    pass
116
117class TLSNoAuthenticationError(TLSAuthenticationError):
118    """The Checker was expecting the other party to authenticate with a
119    certificate chain, but this did not occur."""
120    pass
121
122class TLSAuthenticationTypeError(TLSAuthenticationError):
123    """The Checker was expecting the other party to authenticate with a
124    different type of certificate chain."""
125    pass
126
127class TLSFingerprintError(TLSAuthenticationError):
128    """The Checker was expecting the other party to authenticate with a
129    certificate chain that matches a different fingerprint."""
130    pass
131
132class TLSAuthorizationError(TLSAuthenticationError):
133    """The Checker was expecting the other party to authenticate with a
134    certificate chain that has a different authorization."""
135    pass
136
137class TLSValidationError(TLSAuthenticationError):
138    """The Checker has determined that the other party's certificate
139    chain is invalid."""
140    pass
141
142class TLSFaultError(TLSError):
143    """The other party responded incorrectly to an induced fault.
144
145    This exception will only occur during fault testing, when a
146    TLSConnection's fault variable is set to induce some sort of
147    faulty behavior, and the other party doesn't respond appropriately.
148    """
149    pass
150