147 lines
6.2 KiB
Python
147 lines
6.2 KiB
Python
"""Class for post-handshake certificate checking."""
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from utils.cryptomath import hashAndBase64
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from X509 import X509
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from X509CertChain import X509CertChain
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from errors import *
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class Checker:
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"""This class is passed to a handshake function to check the other
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party's certificate chain.
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If a handshake function completes successfully, but the Checker
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judges the other party's certificate chain to be missing or
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inadequate, a subclass of
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L{tlslite.errors.TLSAuthenticationError} will be raised.
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Currently, the Checker can check either an X.509 or a cryptoID
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chain (for the latter, cryptoIDlib must be installed).
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"""
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def __init__(self, cryptoID=None, protocol=None,
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x509Fingerprint=None,
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x509TrustList=None, x509CommonName=None,
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checkResumedSession=False):
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"""Create a new Checker instance.
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You must pass in one of these argument combinations:
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- cryptoID[, protocol] (requires cryptoIDlib)
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- x509Fingerprint
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- x509TrustList[, x509CommonName] (requires cryptlib_py)
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@type cryptoID: str
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@param cryptoID: A cryptoID which the other party's certificate
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chain must match. The cryptoIDlib module must be installed.
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Mutually exclusive with all of the 'x509...' arguments.
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@type protocol: str
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@param protocol: A cryptoID protocol URI which the other
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party's certificate chain must match. Requires the 'cryptoID'
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argument.
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@type x509Fingerprint: str
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@param x509Fingerprint: A hex-encoded X.509 end-entity
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fingerprint which the other party's end-entity certificate must
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match. Mutually exclusive with the 'cryptoID' and
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'x509TrustList' arguments.
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@type x509TrustList: list of L{tlslite.X509.X509}
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@param x509TrustList: A list of trusted root certificates. The
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other party must present a certificate chain which extends to
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one of these root certificates. The cryptlib_py module must be
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installed. Mutually exclusive with the 'cryptoID' and
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'x509Fingerprint' arguments.
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@type x509CommonName: str
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@param x509CommonName: The end-entity certificate's 'CN' field
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must match this value. For a web server, this is typically a
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server name such as 'www.amazon.com'. Mutually exclusive with
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the 'cryptoID' and 'x509Fingerprint' arguments. Requires the
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'x509TrustList' argument.
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@type checkResumedSession: bool
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@param checkResumedSession: If resumed sessions should be
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checked. This defaults to False, on the theory that if the
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session was checked once, we don't need to bother
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re-checking it.
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"""
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if cryptoID and (x509Fingerprint or x509TrustList):
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raise ValueError()
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if x509Fingerprint and x509TrustList:
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raise ValueError()
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if x509CommonName and not x509TrustList:
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raise ValueError()
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if protocol and not cryptoID:
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raise ValueError()
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if cryptoID:
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import cryptoIDlib #So we raise an error here
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if x509TrustList:
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import cryptlib_py #So we raise an error here
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self.cryptoID = cryptoID
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self.protocol = protocol
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self.x509Fingerprint = x509Fingerprint
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self.x509TrustList = x509TrustList
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self.x509CommonName = x509CommonName
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self.checkResumedSession = checkResumedSession
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def __call__(self, connection):
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"""Check a TLSConnection.
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When a Checker is passed to a handshake function, this will
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be called at the end of the function.
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@type connection: L{tlslite.TLSConnection.TLSConnection}
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@param connection: The TLSConnection to examine.
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@raise tlslite.errors.TLSAuthenticationError: If the other
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party's certificate chain is missing or bad.
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"""
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if not self.checkResumedSession and connection.resumed:
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return
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if self.cryptoID or self.x509Fingerprint or self.x509TrustList:
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if connection._client:
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chain = connection.session.serverCertChain
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else:
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chain = connection.session.clientCertChain
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if self.x509Fingerprint or self.x509TrustList:
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if isinstance(chain, X509CertChain):
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if self.x509Fingerprint:
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if chain.getFingerprint() != self.x509Fingerprint:
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raise TLSFingerprintError(\
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"X.509 fingerprint mismatch: %s, %s" % \
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(chain.getFingerprint(), self.x509Fingerprint))
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else: #self.x509TrustList
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if not chain.validate(self.x509TrustList):
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raise TLSValidationError("X.509 validation failure")
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if self.x509CommonName and \
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(chain.getCommonName() != self.x509CommonName):
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raise TLSAuthorizationError(\
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"X.509 Common Name mismatch: %s, %s" % \
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(chain.getCommonName(), self.x509CommonName))
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elif chain:
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raise TLSAuthenticationTypeError()
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else:
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raise TLSNoAuthenticationError()
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elif self.cryptoID:
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import cryptoIDlib.CertChain
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if isinstance(chain, cryptoIDlib.CertChain.CertChain):
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if chain.cryptoID != self.cryptoID:
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raise TLSFingerprintError(\
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"cryptoID mismatch: %s, %s" % \
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(chain.cryptoID, self.cryptoID))
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if self.protocol:
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if not chain.checkProtocol(self.protocol):
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raise TLSAuthorizationError(\
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"cryptoID protocol mismatch")
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if not chain.validate():
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raise TLSValidationError("cryptoID validation failure")
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elif chain:
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raise TLSAuthenticationTypeError()
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else:
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raise TLSNoAuthenticationError()
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