| # 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 |
| PROTOCOL_TLSv1_1 |
| PROTOCOL_TLSv1_2 |
| |
| The following constants identify various SSL alert message descriptions as per |
| http://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-6 |
| |
| ALERT_DESCRIPTION_CLOSE_NOTIFY |
| ALERT_DESCRIPTION_UNEXPECTED_MESSAGE |
| ALERT_DESCRIPTION_BAD_RECORD_MAC |
| ALERT_DESCRIPTION_RECORD_OVERFLOW |
| ALERT_DESCRIPTION_DECOMPRESSION_FAILURE |
| ALERT_DESCRIPTION_HANDSHAKE_FAILURE |
| ALERT_DESCRIPTION_BAD_CERTIFICATE |
| ALERT_DESCRIPTION_UNSUPPORTED_CERTIFICATE |
| ALERT_DESCRIPTION_CERTIFICATE_REVOKED |
| ALERT_DESCRIPTION_CERTIFICATE_EXPIRED |
| ALERT_DESCRIPTION_CERTIFICATE_UNKNOWN |
| ALERT_DESCRIPTION_ILLEGAL_PARAMETER |
| ALERT_DESCRIPTION_UNKNOWN_CA |
| ALERT_DESCRIPTION_ACCESS_DENIED |
| ALERT_DESCRIPTION_DECODE_ERROR |
| ALERT_DESCRIPTION_DECRYPT_ERROR |
| ALERT_DESCRIPTION_PROTOCOL_VERSION |
| ALERT_DESCRIPTION_INSUFFICIENT_SECURITY |
| ALERT_DESCRIPTION_INTERNAL_ERROR |
| ALERT_DESCRIPTION_USER_CANCELLED |
| ALERT_DESCRIPTION_NO_RENEGOTIATION |
| ALERT_DESCRIPTION_UNSUPPORTED_EXTENSION |
| ALERT_DESCRIPTION_CERTIFICATE_UNOBTAINABLE |
| ALERT_DESCRIPTION_UNRECOGNIZED_NAME |
| ALERT_DESCRIPTION_BAD_CERTIFICATE_STATUS_RESPONSE |
| ALERT_DESCRIPTION_BAD_CERTIFICATE_HASH_VALUE |
| ALERT_DESCRIPTION_UNKNOWN_PSK_IDENTITY |
| """ |
| |
| import textwrap |
| import re |
| import sys |
| import os |
| import collections |
| |
| import _ssl # if we can't import it, let the error propagate |
| |
| from _ssl import OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_INFO, OPENSSL_VERSION |
| from _ssl import _SSLContext |
| from _ssl import ( |
| SSLError, SSLZeroReturnError, SSLWantReadError, SSLWantWriteError, |
| SSLSyscallError, SSLEOFError, |
| ) |
| from _ssl import CERT_NONE, CERT_OPTIONAL, CERT_REQUIRED |
| from _ssl import RAND_status, RAND_egd, RAND_add, RAND_bytes, RAND_pseudo_bytes |
| |
| def _import_symbols(prefix): |
| for n in dir(_ssl): |
| if n.startswith(prefix): |
| globals()[n] = getattr(_ssl, n) |
| |
| _import_symbols('OP_') |
| _import_symbols('ALERT_DESCRIPTION_') |
| _import_symbols('SSL_ERROR_') |
| |
| from _ssl import HAS_SNI, HAS_ECDH, HAS_NPN |
| |
| from _ssl import PROTOCOL_SSLv3, PROTOCOL_SSLv23, PROTOCOL_TLSv1 |
| from _ssl import _OPENSSL_API_VERSION |
| |
| |
| _PROTOCOL_NAMES = { |
| PROTOCOL_TLSv1: "TLSv1", |
| PROTOCOL_SSLv23: "SSLv23", |
| PROTOCOL_SSLv3: "SSLv3", |
| } |
| try: |
| from _ssl import PROTOCOL_SSLv2 |
| _SSLv2_IF_EXISTS = PROTOCOL_SSLv2 |
| except ImportError: |
| _SSLv2_IF_EXISTS = None |
| else: |
| _PROTOCOL_NAMES[PROTOCOL_SSLv2] = "SSLv2" |
| |
| try: |
| from _ssl import PROTOCOL_TLSv1_1, PROTOCOL_TLSv1_2 |
| except ImportError: |
| pass |
| else: |
| _PROTOCOL_NAMES[PROTOCOL_TLSv1_1] = "TLSv1.1" |
| _PROTOCOL_NAMES[PROTOCOL_TLSv1_2] = "TLSv1.2" |
| |
| if sys.platform == "win32": |
| from _ssl import enum_cert_store, X509_ASN_ENCODING, PKCS_7_ASN_ENCODING |
| |
| from socket import getnameinfo as _getnameinfo |
| from socket import socket, AF_INET, SOCK_STREAM, create_connection |
| import base64 # for DER-to-PEM translation |
| import traceback |
| import errno |
| |
| |
| socket_error = OSError # keep that public name in module namespace |
| |
| if _ssl.HAS_TLS_UNIQUE: |
| CHANNEL_BINDING_TYPES = ['tls-unique'] |
| else: |
| CHANNEL_BINDING_TYPES = [] |
| |
| # Disable weak or insecure ciphers by default |
| # (OpenSSL's default setting is 'DEFAULT:!aNULL:!eNULL') |
| _DEFAULT_CIPHERS = 'DEFAULT:!aNULL:!eNULL:!LOW:!EXPORT:!SSLv2' |
| |
| |
| class CertificateError(ValueError): |
| pass |
| |
| |
| def _dnsname_to_pat(dn, max_wildcards=1): |
| pats = [] |
| for frag in dn.split(r'.'): |
| if frag.count('*') > max_wildcards: |
| # Issue #17980: avoid denials of service by refusing more |
| # than one wildcard per fragment. A survey of established |
| # policy among SSL implementations showed it to be a |
| # reasonable choice. |
| raise CertificateError( |
| "too many wildcards in certificate DNS name: " + repr(dn)) |
| if frag == '*': |
| # When '*' is a fragment by itself, it matches a non-empty dotless |
| # fragment. |
| pats.append('[^.]+') |
| else: |
| # Otherwise, '*' matches any dotless fragment. |
| frag = re.escape(frag) |
| pats.append(frag.replace(r'\*', '[^.]*')) |
| return re.compile(r'\A' + r'\.'.join(pats) + r'\Z', re.IGNORECASE) |
| |
| |
| def match_hostname(cert, hostname): |
| """Verify that *cert* (in decoded format as returned by |
| SSLSocket.getpeercert()) matches the *hostname*. RFC 2818 rules |
| are mostly followed, but IP addresses are not accepted for *hostname*. |
| |
| CertificateError is raised on failure. On success, the function |
| returns nothing. |
| """ |
| if not cert: |
| raise ValueError("empty or no certificate") |
| dnsnames = [] |
| san = cert.get('subjectAltName', ()) |
| for key, value in san: |
| if key == 'DNS': |
| if _dnsname_to_pat(value).match(hostname): |
| return |
| dnsnames.append(value) |
| if not dnsnames: |
| # The subject is only checked when there is no dNSName entry |
| # in subjectAltName |
| for sub in cert.get('subject', ()): |
| for key, value in sub: |
| # XXX according to RFC 2818, the most specific Common Name |
| # must be used. |
| if key == 'commonName': |
| if _dnsname_to_pat(value).match(hostname): |
| return |
| dnsnames.append(value) |
| if len(dnsnames) > 1: |
| raise CertificateError("hostname %r " |
| "doesn't match either of %s" |
| % (hostname, ', '.join(map(repr, dnsnames)))) |
| elif len(dnsnames) == 1: |
| raise CertificateError("hostname %r " |
| "doesn't match %r" |
| % (hostname, dnsnames[0])) |
| else: |
| raise CertificateError("no appropriate commonName or " |
| "subjectAltName fields were found") |
| |
| |
| DefaultVerifyPaths = collections.namedtuple("DefaultVerifyPaths", |
| "cafile capath openssl_cafile_env openssl_cafile openssl_capath_env " |
| "openssl_capath") |
| |
| def get_default_verify_paths(): |
| """Return paths to default cafile and capath. |
| """ |
| parts = _ssl.get_default_verify_paths() |
| |
| # environment vars shadow paths |
| cafile = os.environ.get(parts[0], parts[1]) |
| capath = os.environ.get(parts[2], parts[3]) |
| |
| return DefaultVerifyPaths(cafile if os.path.isfile(cafile) else None, |
| capath if os.path.isdir(capath) else None, |
| *parts) |
| |
| |
| class SSLContext(_SSLContext): |
| """An SSLContext holds various SSL-related configuration options and |
| data, such as certificates and possibly a private key.""" |
| |
| __slots__ = ('protocol', '__weakref__') |
| |
| def __new__(cls, protocol, *args, **kwargs): |
| self = _SSLContext.__new__(cls, protocol) |
| if protocol != _SSLv2_IF_EXISTS: |
| self.set_ciphers(_DEFAULT_CIPHERS) |
| return self |
| |
| def __init__(self, protocol): |
| self.protocol = protocol |
| |
| def wrap_socket(self, sock, server_side=False, |
| do_handshake_on_connect=True, |
| suppress_ragged_eofs=True, |
| server_hostname=None): |
| return SSLSocket(sock=sock, server_side=server_side, |
| do_handshake_on_connect=do_handshake_on_connect, |
| suppress_ragged_eofs=suppress_ragged_eofs, |
| server_hostname=server_hostname, |
| _context=self) |
| |
| def set_npn_protocols(self, npn_protocols): |
| protos = bytearray() |
| for protocol in npn_protocols: |
| b = bytes(protocol, 'ascii') |
| if len(b) == 0 or len(b) > 255: |
| raise SSLError('NPN protocols must be 1 to 255 in length') |
| protos.append(len(b)) |
| protos.extend(b) |
| |
| self._set_npn_protocols(protos) |
| |
| |
| class SSLSocket(socket): |
| """This class implements a subtype of socket.socket that wraps |
| the underlying OS socket in an SSL context when necessary, and |
| provides read and write methods over that channel.""" |
| |
| def __init__(self, sock=None, keyfile=None, certfile=None, |
| server_side=False, cert_reqs=CERT_NONE, |
| ssl_version=PROTOCOL_SSLv23, ca_certs=None, |
| do_handshake_on_connect=True, |
| family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None, |
| suppress_ragged_eofs=True, npn_protocols=None, ciphers=None, |
| server_hostname=None, |
| _context=None): |
| |
| if _context: |
| self._context = _context |
| else: |
| if server_side and not certfile: |
| raise ValueError("certfile must be specified for server-side " |
| "operations") |
| if keyfile and not certfile: |
| raise ValueError("certfile must be specified") |
| if certfile and not keyfile: |
| keyfile = certfile |
| self._context = SSLContext(ssl_version) |
| self._context.verify_mode = cert_reqs |
| if ca_certs: |
| self._context.load_verify_locations(ca_certs) |
| if certfile: |
| self._context.load_cert_chain(certfile, keyfile) |
| if npn_protocols: |
| self._context.set_npn_protocols(npn_protocols) |
| if ciphers: |
| self._context.set_ciphers(ciphers) |
| self.keyfile = keyfile |
| self.certfile = certfile |
| self.cert_reqs = cert_reqs |
| self.ssl_version = ssl_version |
| self.ca_certs = ca_certs |
| self.ciphers = ciphers |
| if server_side and server_hostname: |
| raise ValueError("server_hostname can only be specified " |
| "in client mode") |
| self.server_side = server_side |
| self.server_hostname = server_hostname |
| self.do_handshake_on_connect = do_handshake_on_connect |
| self.suppress_ragged_eofs = suppress_ragged_eofs |
| if sock is not None: |
| socket.__init__(self, |
| family=sock.family, |
| type=sock.type, |
| proto=sock.proto, |
| fileno=sock.fileno()) |
| self.settimeout(sock.gettimeout()) |
| sock.detach() |
| elif fileno is not None: |
| socket.__init__(self, fileno=fileno) |
| else: |
| socket.__init__(self, family=family, type=type, proto=proto) |
| |
| # See if we are connected |
| try: |
| self.getpeername() |
| except OSError as e: |
| if e.errno != errno.ENOTCONN: |
| raise |
| connected = False |
| else: |
| connected = True |
| |
| self._closed = False |
| self._sslobj = None |
| self._connected = connected |
| if connected: |
| # create the SSL object |
| try: |
| self._sslobj = self._context._wrap_socket(self, server_side, |
| server_hostname) |
| if do_handshake_on_connect: |
| timeout = self.gettimeout() |
| if timeout == 0.0: |
| # non-blocking |
| raise ValueError("do_handshake_on_connect should not be specified for non-blocking sockets") |
| self.do_handshake() |
| |
| except OSError as x: |
| self.close() |
| raise x |
| |
| @property |
| def context(self): |
| return self._context |
| |
| @context.setter |
| def context(self, ctx): |
| self._context = ctx |
| self._sslobj.context = ctx |
| |
| def dup(self): |
| raise NotImplemented("Can't dup() %s instances" % |
| self.__class__.__name__) |
| |
| def _checkClosed(self, msg=None): |
| # raise an exception here if you wish to check for spurious closes |
| pass |
| |
| def _check_connected(self): |
| if not self._connected: |
| # getpeername() will raise ENOTCONN if the socket is really |
| # not connected; note that we can be connected even without |
| # _connected being set, e.g. if connect() first returned |
| # EAGAIN. |
| self.getpeername() |
| |
| def read(self, len=0, buffer=None): |
| """Read up to LEN bytes and return them. |
| Return zero-length string on EOF.""" |
| |
| self._checkClosed() |
| if not self._sslobj: |
| raise ValueError("Read on closed or unwrapped SSL socket.") |
| try: |
| if buffer is not None: |
| v = self._sslobj.read(len, buffer) |
| else: |
| v = self._sslobj.read(len or 1024) |
| return v |
| except SSLError as x: |
| if x.args[0] == SSL_ERROR_EOF and self.suppress_ragged_eofs: |
| if buffer is not None: |
| return 0 |
| else: |
| return b'' |
| else: |
| raise |
| |
| def write(self, data): |
| """Write DATA to the underlying SSL channel. Returns |
| number of bytes of DATA actually transmitted.""" |
| |
| self._checkClosed() |
| if not self._sslobj: |
| raise ValueError("Write on closed or unwrapped SSL socket.") |
| return self._sslobj.write(data) |
| |
| def getpeercert(self, binary_form=False): |
| """Returns a formatted version of the data in the |
| certificate provided by the other end of the SSL channel. |
| Return None if no certificate was provided, {} if a |
| certificate was provided, but not validated.""" |
| |
| self._checkClosed() |
| self._check_connected() |
| return self._sslobj.peer_certificate(binary_form) |
| |
| def selected_npn_protocol(self): |
| self._checkClosed() |
| if not self._sslobj or not _ssl.HAS_NPN: |
| return None |
| else: |
| return self._sslobj.selected_npn_protocol() |
| |
| def cipher(self): |
| self._checkClosed() |
| if not self._sslobj: |
| return None |
| else: |
| return self._sslobj.cipher() |
| |
| def compression(self): |
| self._checkClosed() |
| if not self._sslobj: |
| return None |
| else: |
| return self._sslobj.compression() |
| |
| def send(self, data, flags=0): |
| self._checkClosed() |
| if self._sslobj: |
| if flags != 0: |
| raise ValueError( |
| "non-zero flags not allowed in calls to send() on %s" % |
| self.__class__) |
| try: |
| v = self._sslobj.write(data) |
| except SSLError as x: |
| if x.args[0] == SSL_ERROR_WANT_READ: |
| return 0 |
| elif x.args[0] == SSL_ERROR_WANT_WRITE: |
| return 0 |
| else: |
| raise |
| else: |
| return v |
| else: |
| return socket.send(self, data, flags) |
| |
| def sendto(self, data, flags_or_addr, addr=None): |
| self._checkClosed() |
| if self._sslobj: |
| raise ValueError("sendto not allowed on instances of %s" % |
| self.__class__) |
| elif addr is None: |
| return socket.sendto(self, data, flags_or_addr) |
| else: |
| return socket.sendto(self, data, flags_or_addr, addr) |
| |
| def sendmsg(self, *args, **kwargs): |
| # Ensure programs don't send data unencrypted if they try to |
| # use this method. |
| raise NotImplementedError("sendmsg not allowed on instances of %s" % |
| self.__class__) |
| |
| def sendall(self, data, flags=0): |
| self._checkClosed() |
| if self._sslobj: |
| if flags != 0: |
| raise ValueError( |
| "non-zero flags not allowed in calls to sendall() on %s" % |
| self.__class__) |
| amount = len(data) |
| count = 0 |
| while (count < amount): |
| v = self.send(data[count:]) |
| count += v |
| return amount |
| else: |
| return socket.sendall(self, data, flags) |
| |
| def recv(self, buflen=1024, flags=0): |
| self._checkClosed() |
| if self._sslobj: |
| if flags != 0: |
| raise ValueError( |
| "non-zero flags not allowed in calls to recv() on %s" % |
| self.__class__) |
| return self.read(buflen) |
| else: |
| return socket.recv(self, buflen, flags) |
| |
| def recv_into(self, buffer, nbytes=None, flags=0): |
| self._checkClosed() |
| if buffer and (nbytes is None): |
| nbytes = len(buffer) |
| elif nbytes is None: |
| nbytes = 1024 |
| if self._sslobj: |
| if flags != 0: |
| raise ValueError( |
| "non-zero flags not allowed in calls to recv_into() on %s" % |
| self.__class__) |
| return self.read(nbytes, buffer) |
| else: |
| return socket.recv_into(self, buffer, nbytes, flags) |
| |
| def recvfrom(self, buflen=1024, flags=0): |
| self._checkClosed() |
| if self._sslobj: |
| raise ValueError("recvfrom not allowed on instances of %s" % |
| self.__class__) |
| else: |
| return socket.recvfrom(self, buflen, flags) |
| |
| def recvfrom_into(self, buffer, nbytes=None, flags=0): |
| self._checkClosed() |
| if self._sslobj: |
| raise ValueError("recvfrom_into not allowed on instances of %s" % |
| self.__class__) |
| else: |
| return socket.recvfrom_into(self, buffer, nbytes, flags) |
| |
| def recvmsg(self, *args, **kwargs): |
| raise NotImplementedError("recvmsg not allowed on instances of %s" % |
| self.__class__) |
| |
| def recvmsg_into(self, *args, **kwargs): |
| raise NotImplementedError("recvmsg_into not allowed on instances of " |
| "%s" % self.__class__) |
| |
| def pending(self): |
| self._checkClosed() |
| if self._sslobj: |
| return self._sslobj.pending() |
| else: |
| return 0 |
| |
| def shutdown(self, how): |
| self._checkClosed() |
| self._sslobj = None |
| socket.shutdown(self, how) |
| |
| def unwrap(self): |
| if self._sslobj: |
| s = self._sslobj.shutdown() |
| self._sslobj = None |
| return s |
| else: |
| raise ValueError("No SSL wrapper around " + str(self)) |
| |
| def _real_close(self): |
| self._sslobj = None |
| socket._real_close(self) |
| |
| def do_handshake(self, block=False): |
| """Perform a TLS/SSL handshake.""" |
| self._check_connected() |
| timeout = self.gettimeout() |
| try: |
| if timeout == 0.0 and block: |
| self.settimeout(None) |
| self._sslobj.do_handshake() |
| finally: |
| self.settimeout(timeout) |
| |
| def _real_connect(self, addr, connect_ex): |
| if self.server_side: |
| raise ValueError("can't connect in server-side mode") |
| # 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._connected: |
| raise ValueError("attempt to connect already-connected SSLSocket!") |
| self._sslobj = self.context._wrap_socket(self, False, self.server_hostname) |
| try: |
| if connect_ex: |
| rc = socket.connect_ex(self, addr) |
| else: |
| rc = None |
| socket.connect(self, addr) |
| if not rc: |
| self._connected = True |
| if self.do_handshake_on_connect: |
| self.do_handshake() |
| return rc |
| except OSError: |
| self._sslobj = None |
| raise |
| |
| def connect(self, addr): |
| """Connects to remote ADDR, and then wraps the connection in |
| an SSL channel.""" |
| self._real_connect(addr, False) |
| |
| def connect_ex(self, addr): |
| """Connects to remote ADDR, and then wraps the connection in |
| an SSL channel.""" |
| return self._real_connect(addr, True) |
| |
| def accept(self): |
| """Accepts a new connection from a remote client, and returns |
| a tuple containing that new connection wrapped with a server-side |
| SSL channel, and the address of the remote client.""" |
| |
| newsock, addr = socket.accept(self) |
| newsock = self.context.wrap_socket(newsock, |
| do_handshake_on_connect=self.do_handshake_on_connect, |
| suppress_ragged_eofs=self.suppress_ragged_eofs, |
| server_side=True) |
| return newsock, addr |
| |
| def get_channel_binding(self, cb_type="tls-unique"): |
| """Get channel binding data for current connection. Raise ValueError |
| if the requested `cb_type` is not supported. Return bytes of the data |
| or None if the data is not available (e.g. before the handshake). |
| """ |
| if cb_type not in CHANNEL_BINDING_TYPES: |
| raise ValueError("Unsupported channel binding type") |
| if cb_type != "tls-unique": |
| raise NotImplementedError( |
| "{0} channel binding type not implemented" |
| .format(cb_type)) |
| if self._sslobj is None: |
| return None |
| return self._sslobj.tls_unique_cb() |
| |
| |
| def wrap_socket(sock, keyfile=None, certfile=None, |
| server_side=False, cert_reqs=CERT_NONE, |
| ssl_version=PROTOCOL_SSLv23, ca_certs=None, |
| do_handshake_on_connect=True, |
| suppress_ragged_eofs=True, |
| ciphers=None): |
| |
| return SSLSocket(sock=sock, keyfile=keyfile, certfile=certfile, |
| server_side=server_side, cert_reqs=cert_reqs, |
| ssl_version=ssl_version, ca_certs=ca_certs, |
| do_handshake_on_connect=do_handshake_on_connect, |
| suppress_ragged_eofs=suppress_ragged_eofs, |
| ciphers=ciphers) |
| |
| # some utility functions |
| |
| def cert_time_to_seconds(cert_time): |
| """Takes a date-time string in standard ASN1_print form |
| ("MON DAY 24HOUR:MINUTE:SEC YEAR TIMEZONE") and return |
| a Python time value in seconds past the epoch.""" |
| |
| import time |
| return time.mktime(time.strptime(cert_time, "%b %d %H:%M:%S %Y GMT")) |
| |
| PEM_HEADER = "-----BEGIN CERTIFICATE-----" |
| PEM_FOOTER = "-----END CERTIFICATE-----" |
| |
| def DER_cert_to_PEM_cert(der_cert_bytes): |
| """Takes a certificate in binary DER format and returns the |
| PEM version of it as a string.""" |
| |
| f = str(base64.standard_b64encode(der_cert_bytes), 'ASCII', 'strict') |
| return (PEM_HEADER + '\n' + |
| textwrap.fill(f, 64) + '\n' + |
| PEM_FOOTER + '\n') |
| |
| def PEM_cert_to_DER_cert(pem_cert_string): |
| """Takes a certificate in ASCII PEM format and returns the |
| DER-encoded version of it as a byte sequence""" |
| |
| if not pem_cert_string.startswith(PEM_HEADER): |
| raise ValueError("Invalid PEM encoding; must start with %s" |
| % PEM_HEADER) |
| if not pem_cert_string.strip().endswith(PEM_FOOTER): |
| raise ValueError("Invalid PEM encoding; must end with %s" |
| % PEM_FOOTER) |
| d = pem_cert_string.strip()[len(PEM_HEADER):-len(PEM_FOOTER)] |
| return base64.decodebytes(d.encode('ASCII', 'strict')) |
| |
| def get_server_certificate(addr, ssl_version=PROTOCOL_SSLv3, ca_certs=None): |
| """Retrieve the certificate from the server at the specified address, |
| and return it as a PEM-encoded string. |
| If 'ca_certs' is specified, validate the server cert against it. |
| If 'ssl_version' is specified, use it in the connection attempt.""" |
| |
| host, port = addr |
| if (ca_certs is not None): |
| cert_reqs = CERT_REQUIRED |
| else: |
| cert_reqs = CERT_NONE |
| s = create_connection(addr) |
| s = wrap_socket(s, ssl_version=ssl_version, |
| cert_reqs=cert_reqs, ca_certs=ca_certs) |
| dercert = s.getpeercert(True) |
| s.close() |
| return DER_cert_to_PEM_cert(dercert) |
| |
| def get_protocol_name(protocol_code): |
| return _PROTOCOL_NAMES.get(protocol_code, '<unknown>') |