cpython/Lib/ssl.py

254 lines
8.3 KiB
Python

# Wrapper module for _ssl, providing some additional facilities
# implemented in Python. Written by Bill Janssen.
"""\
This module provides some more Pythonic support for SSL.
Object types:
sslsocket -- subtype of socket.socket which does SSL over the socket
Exceptions:
sslerror -- exception raised for I/O errors
Functions:
cert_time_to_seconds -- convert time string used for certificate
notBefore and notAfter functions to integer
seconds past the Epoch (the time values
returned from time.time())
fetch_server_certificate (HOST, PORT) -- fetch the certificate provided
by the server running on HOST at port PORT. No
validation of the certificate is performed.
Integer constants:
SSL_ERROR_ZERO_RETURN
SSL_ERROR_WANT_READ
SSL_ERROR_WANT_WRITE
SSL_ERROR_WANT_X509_LOOKUP
SSL_ERROR_SYSCALL
SSL_ERROR_SSL
SSL_ERROR_WANT_CONNECT
SSL_ERROR_EOF
SSL_ERROR_INVALID_ERROR_CODE
The following group define certificate requirements that one side is
allowing/requiring from the other side:
CERT_NONE - no certificates from the other side are required (or will
be looked at if provided)
CERT_OPTIONAL - certificates are not required, but if provided will be
validated, and if validation fails, the connection will
also fail
CERT_REQUIRED - certificates are required, and will be validated, and
if validation fails, the connection will also fail
The following constants identify various SSL protocol variants:
PROTOCOL_SSLv2
PROTOCOL_SSLv3
PROTOCOL_SSLv23
PROTOCOL_TLSv1
"""
import os, sys
import _ssl # if we can't import it, let the error propagate
from socket import socket
from _ssl import sslerror
from _ssl import CERT_NONE, CERT_OPTIONAL, CERT_REQUIRED
from _ssl import PROTOCOL_SSLv2, PROTOCOL_SSLv3, PROTOCOL_SSLv23, PROTOCOL_TLSv1
# Root certs:
#
# The "ca_certs" argument to sslsocket() expects a file containing one or more
# certificates that are roots of various certificate signing chains. This file
# contains the certificates in PEM format (RFC ) where each certificate is
# encoded in base64 encoding and surrounded with a header and footer:
# -----BEGIN CERTIFICATE-----
# ... (CA certificate in base64 encoding) ...
# -----END CERTIFICATE-----
# The various certificates in the file are just concatenated together:
# -----BEGIN CERTIFICATE-----
# ... (CA certificate in base64 encoding) ...
# -----END CERTIFICATE-----
# -----BEGIN CERTIFICATE-----
# ... (a second CA certificate in base64 encoding) ...
# -----END CERTIFICATE-----
#
# Some "standard" root certificates are available at
#
# http://www.thawte.com/roots/ (for Thawte roots)
# http://www.verisign.com/support/roots.html (for Verisign)
class sslsocket (socket):
def __init__(self, sock, keyfile=None, certfile=None,
server_side=False, cert_reqs=CERT_NONE,
ssl_version=PROTOCOL_SSLv23, ca_certs=None):
socket.__init__(self, _sock=sock._sock)
if certfile and not keyfile:
keyfile = certfile
if server_side:
self._sslobj = _ssl.sslwrap(self._sock, 1, keyfile, certfile,
cert_reqs, ssl_version, ca_certs)
else:
# see if it's connected
try:
socket.getpeername(self)
except:
# no, no connection yet
self._sslobj = None
else:
# yes, create the SSL object
self._sslobj = _ssl.sslwrap(self._sock, 0, keyfile, certfile,
cert_reqs, ssl_version, ca_certs)
self.keyfile = keyfile
self.certfile = certfile
self.cert_reqs = cert_reqs
self.ssl_version = ssl_version
self.ca_certs = ca_certs
def read(self, len=1024):
return self._sslobj.read(len)
def write(self, data):
return self._sslobj.write(data)
def getpeercert(self):
return self._sslobj.peer_certificate()
def send (self, data, flags=0):
if flags != 0:
raise ValueError(
"non-zero flags not allowed in calls to send() on %s" %
self.__class__)
return self._sslobj.write(data)
def send_to (self, data, addr, flags=0):
raise ValueError("send_to not allowed on instances of %s" %
self.__class__)
def sendall (self, data, flags=0):
if flags != 0:
raise ValueError(
"non-zero flags not allowed in calls to sendall() on %s" %
self.__class__)
return self._sslobj.write(data)
def recv (self, buflen=1024, flags=0):
if flags != 0:
raise ValueError(
"non-zero flags not allowed in calls to sendall() on %s" %
self.__class__)
return self._sslobj.read(data, buflen)
def recv_from (self, addr, buflen=1024, flags=0):
raise ValueError("recv_from not allowed on instances of %s" %
self.__class__)
def shutdown(self):
if self._sslobj:
self._sslobj.shutdown()
self._sslobj = None
else:
socket.shutdown(self)
def close(self):
if self._sslobj:
self.shutdown()
else:
socket.close(self)
def connect(self, addr):
# Here we assume that the socket is client-side, and not
# connected at the time of the call. We connect it, then wrap it.
if self._sslobj or (self.getsockname()[1] != 0):
raise ValueError("attempt to connect already-connected sslsocket!")
socket.connect(self, addr)
self._sslobj = _ssl.sslwrap(self._sock, 0, self.keyfile, self.certfile,
self.cert_reqs, self.ssl_version,
self.ca_certs)
def accept(self):
raise ValueError("accept() not supported on an sslsocket")
# some utility functions
def cert_time_to_seconds(cert_time):
import time
return time.mktime(time.strptime(cert_time, "%b %d %H:%M:%S %Y GMT"))
# a replacement for the old socket.ssl function
def sslwrap_simple (sock, keyfile=None, certfile=None):
return _ssl.sslwrap(sock._sock, 0, keyfile, certfile, CERT_NONE,
PROTOCOL_SSLv23, None)
# fetch the certificate that the server is providing in PEM form
def fetch_server_certificate (host, port):
import re, tempfile, os
def subproc(cmd):
from subprocess import Popen, PIPE, STDOUT
proc = Popen(cmd, stdout=PIPE, stderr=STDOUT, shell=True)
status = proc.wait()
output = proc.stdout.read()
return status, output
def strip_to_x509_cert(certfile_contents, outfile=None):
m = re.search(r"^([-]+BEGIN CERTIFICATE[-]+[\r]*\n"
r".*[\r]*^[-]+END CERTIFICATE[-]+)$",
certfile_contents, re.MULTILINE | re.DOTALL)
if not m:
return None
else:
tn = tempfile.mktemp()
fp = open(tn, "w")
fp.write(m.group(1) + "\n")
fp.close()
try:
tn2 = (outfile or tempfile.mktemp())
status, output = subproc(r'openssl x509 -in "%s" -out "%s"' %
(tn, tn2))
if status != 0:
raise OperationError(status, tsig, output)
fp = open(tn2, 'rb')
data = fp.read()
fp.close()
os.unlink(tn2)
return data
finally:
os.unlink(tn)
if sys.platform.startswith("win"):
tfile = tempfile.mktemp()
fp = open(tfile, "w")
fp.write("quit\n")
fp.close()
try:
status, output = subproc(
'openssl s_client -connect "%s:%s" -showcerts < "%s"' %
(host, port, tfile))
finally:
os.unlink(tfile)
else:
status, output = subproc(
'openssl s_client -connect "%s:%s" -showcerts < /dev/null' %
(host, port))
if status != 0:
raise OSError(status)
certtext = strip_to_x509_cert(output)
if not certtext:
raise ValueError("Invalid response received from server at %s:%s" %
(host, port))
return certtext