Source code for ssl

# 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_TLS
PROTOCOL_TLS_CLIENT
PROTOCOL_TLS_SERVER
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 sys
import os
from collections import namedtuple
from enum import Enum as _Enum, IntEnum as _IntEnum, IntFlag as _IntFlag

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, MemoryBIO, SSLSession
from _ssl import (
    SSLError, SSLZeroReturnError, SSLWantReadError, SSLWantWriteError,
    SSLSyscallError, SSLEOFError, SSLCertVerificationError
    )
from _ssl import txt2obj as _txt2obj, nid2obj as _nid2obj
from _ssl import RAND_status, RAND_add, RAND_bytes, RAND_pseudo_bytes
try:
    from _ssl import RAND_egd
except ImportError:
    # LibreSSL does not provide RAND_egd
    pass


from _ssl import (
    HAS_SNI, HAS_ECDH, HAS_NPN, HAS_ALPN, HAS_SSLv2, HAS_SSLv3, HAS_TLSv1,
    HAS_TLSv1_1, HAS_TLSv1_2, HAS_TLSv1_3
)
from _ssl import _DEFAULT_CIPHERS, _OPENSSL_API_VERSION


_IntEnum._convert(
    '_SSLMethod', __name__,
    lambda name: name.startswith('PROTOCOL_') and name != 'PROTOCOL_SSLv23',
    source=_ssl)

_IntFlag._convert(
    'Options', __name__,
    lambda name: name.startswith('OP_'),
    source=_ssl)

_IntEnum._convert(
    'AlertDescription', __name__,
    lambda name: name.startswith('ALERT_DESCRIPTION_'),
    source=_ssl)

_IntEnum._convert(
    'SSLErrorNumber', __name__,
    lambda name: name.startswith('SSL_ERROR_'),
    source=_ssl)

_IntFlag._convert(
    'VerifyFlags', __name__,
    lambda name: name.startswith('VERIFY_'),
    source=_ssl)

_IntEnum._convert(
    'VerifyMode', __name__,
    lambda name: name.startswith('CERT_'),
    source=_ssl)

PROTOCOL_SSLv23 = _SSLMethod.PROTOCOL_SSLv23 = _SSLMethod.PROTOCOL_TLS
_PROTOCOL_NAMES = {value: name for name, value in _SSLMethod.__members__.items()}

_SSLv2_IF_EXISTS = getattr(_SSLMethod, 'PROTOCOL_SSLv2', None)


[docs]class TLSVersion(_IntEnum): MINIMUM_SUPPORTED = _ssl.PROTO_MINIMUM_SUPPORTED SSLv3 = _ssl.PROTO_SSLv3 TLSv1 = _ssl.PROTO_TLSv1 TLSv1_1 = _ssl.PROTO_TLSv1_1 TLSv1_2 = _ssl.PROTO_TLSv1_2 TLSv1_3 = _ssl.PROTO_TLSv1_3 MAXIMUM_SUPPORTED = _ssl.PROTO_MAXIMUM_SUPPORTED
if sys.platform == "win32": from _ssl import enum_certificates, enum_crls from socket import socket, AF_INET, SOCK_STREAM, create_connection from socket import SOL_SOCKET, SO_TYPE import socket as _socket import base64 # for DER-to-PEM translation import errno import warnings socket_error = OSError # keep that public name in module namespace CHANNEL_BINDING_TYPES = ['tls-unique'] HAS_NEVER_CHECK_COMMON_NAME = hasattr(_ssl, 'HOSTFLAG_NEVER_CHECK_SUBJECT') _RESTRICTED_SERVER_CIPHERS = _DEFAULT_CIPHERS CertificateError = SSLCertVerificationError def _dnsname_match(dn, hostname): """Matching according to RFC 6125, section 6.4.3 - Hostnames are compared lower case. - For IDNA, both dn and hostname must be encoded as IDN A-label (ACE). - Partial wildcards like 'www*.example.org', multiple wildcards, sole wildcard or wildcards in labels other then the left-most label are not supported and a CertificateError is raised. - A wildcard must match at least one character. """ if not dn: return False wildcards = dn.count('*') # speed up common case w/o wildcards if not wildcards: return dn.lower() == hostname.lower() if wildcards > 1: raise CertificateError( "too many wildcards in certificate DNS name: {!r}.".format(dn)) dn_leftmost, sep, dn_remainder = dn.partition('.') if '*' in dn_remainder: # Only match wildcard in leftmost segment. raise CertificateError( "wildcard can only be present in the leftmost label: " "{!r}.".format(dn)) if not sep: # no right side raise CertificateError( "sole wildcard without additional labels are not support: " "{!r}.".format(dn)) if dn_leftmost != '*': # no partial wildcard matching raise CertificateError( "partial wildcards in leftmost label are not supported: " "{!r}.".format(dn)) hostname_leftmost, sep, hostname_remainder = hostname.partition('.') if not hostname_leftmost or not sep: # wildcard must match at least one char return False return dn_remainder.lower() == hostname_remainder.lower() def _inet_paton(ipname): """Try to convert an IP address to packed binary form Supports IPv4 addresses on all platforms and IPv6 on platforms with IPv6 support. """ # inet_aton() also accepts strings like '1' if ipname.count('.') == 3: try: return _socket.inet_aton(ipname) except OSError: pass try: return _socket.inet_pton(_socket.AF_INET6, ipname) except OSError: raise ValueError("{!r} is neither an IPv4 nor an IP6 " "address.".format(ipname)) except AttributeError: # AF_INET6 not available pass raise ValueError("{!r} is not an IPv4 address.".format(ipname)) def _ipaddress_match(ipname, host_ip): """Exact matching of IP addresses. RFC 6125 explicitly doesn't define an algorithm for this (section 1.7.2 - "Out of Scope"). """ # OpenSSL may add a trailing newline to a subjectAltName's IP address ip = _inet_paton(ipname.rstrip()) return ip == host_ip
[docs]def match_hostname(cert, hostname): """Verify that *cert* (in decoded format as returned by SSLSocket.getpeercert()) matches the *hostname*. RFC 2818 and RFC 6125 rules are followed. The function matches IP addresses rather than dNSNames if hostname is a valid ipaddress string. IPv4 addresses are supported on all platforms. IPv6 addresses are supported on platforms with IPv6 support (AF_INET6 and inet_pton). CertificateError is raised on failure. On success, the function returns nothing. """ if not cert: raise ValueError("empty or no certificate, match_hostname needs a " "SSL socket or SSL context with either " "CERT_OPTIONAL or CERT_REQUIRED") try: host_ip = _inet_paton(hostname) except ValueError: # Not an IP address (common case) host_ip = None dnsnames = [] san = cert.get('subjectAltName', ()) for key, value in san: if key == 'DNS': if host_ip is None and _dnsname_match(value, hostname): return dnsnames.append(value) elif key == 'IP Address': if host_ip is not None and _ipaddress_match(value, host_ip): 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_match(value, 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 = namedtuple("DefaultVerifyPaths", "cafile capath openssl_cafile_env openssl_cafile openssl_capath_env " "openssl_capath")
[docs]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 _ASN1Object(namedtuple("_ASN1Object", "nid shortname longname oid")): """ASN.1 object identifier lookup """ __slots__ = () def __new__(cls, oid): return super().__new__(cls, *_txt2obj(oid, name=False)) @classmethod def fromnid(cls, nid): """Create _ASN1Object from OpenSSL numeric ID """ return super().__new__(cls, *_nid2obj(nid)) @classmethod def fromname(cls, name): """Create _ASN1Object from short name, long name or OID """ return super().__new__(cls, *_txt2obj(name, name=True)) class Purpose(_ASN1Object, _Enum): """SSLContext purpose flags with X509v3 Extended Key Usage objects """ SERVER_AUTH = '1.3.6.1.5.5.7.3.1' CLIENT_AUTH = '1.3.6.1.5.5.7.3.2'
[docs]class SSLContext(_SSLContext): """An SSLContext holds various SSL-related configuration options and data, such as certificates and possibly a private key.""" _windows_cert_stores = ("CA", "ROOT") sslsocket_class = None # SSLSocket is assigned later. sslobject_class = None # SSLObject is assigned later. def __new__(cls, protocol=PROTOCOL_TLS, *args, **kwargs): self = _SSLContext.__new__(cls, protocol) return self def _encode_hostname(self, hostname): if hostname is None: return None elif isinstance(hostname, str): return hostname.encode('idna').decode('ascii') else: return hostname.decode('ascii') def wrap_socket(self, sock, server_side=False, do_handshake_on_connect=True, suppress_ragged_eofs=True, server_hostname=None, session=None): # SSLSocket class handles server_hostname encoding before it calls # ctx._wrap_socket() return self.sslsocket_class._create( 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, session=session ) def wrap_bio(self, incoming, outgoing, server_side=False, server_hostname=None, session=None): # Need to encode server_hostname here because _wrap_bio() can only # handle ASCII str. return self.sslobject_class._create( incoming, outgoing, server_side=server_side, server_hostname=self._encode_hostname(server_hostname), session=session, 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) def set_servername_callback(self, server_name_callback): if server_name_callback is None: self.sni_callback = None else: if not callable(server_name_callback): raise TypeError("not a callable object") def shim_cb(sslobj, servername, sslctx): servername = self._encode_hostname(servername) return server_name_callback(sslobj, servername, sslctx) self.sni_callback = shim_cb def set_alpn_protocols(self, alpn_protocols): protos = bytearray() for protocol in alpn_protocols: b = bytes(protocol, 'ascii') if len(b) == 0 or len(b) > 255: raise SSLError('ALPN protocols must be 1 to 255 in length') protos.append(len(b)) protos.extend(b) self._set_alpn_protocols(protos) def _load_windows_store_certs(self, storename, purpose): certs = bytearray() try: for cert, encoding, trust in enum_certificates(storename): # CA certs are never PKCS#7 encoded if encoding == "x509_asn": if trust is True or purpose.oid in trust: certs.extend(cert) except PermissionError: warnings.warn("unable to enumerate Windows certificate store") if certs: self.load_verify_locations(cadata=certs) return certs def load_default_certs(self, purpose=Purpose.SERVER_AUTH): if not isinstance(purpose, _ASN1Object): raise TypeError(purpose) if sys.platform == "win32": for storename in self._windows_cert_stores: self._load_windows_store_certs(storename, purpose) self.set_default_verify_paths() if hasattr(_SSLContext, 'minimum_version'): @property def minimum_version(self): return TLSVersion(super().minimum_version) @minimum_version.setter def minimum_version(self, value): if value == TLSVersion.SSLv3: self.options &= ~Options.OP_NO_SSLv3 super(SSLContext, SSLContext).minimum_version.__set__(self, value) @property def maximum_version(self): return TLSVersion(super().maximum_version) @maximum_version.setter def maximum_version(self, value): super(SSLContext, SSLContext).maximum_version.__set__(self, value) @property def options(self): return Options(super().options) @options.setter def options(self, value): super(SSLContext, SSLContext).options.__set__(self, value) if hasattr(_ssl, 'HOSTFLAG_NEVER_CHECK_SUBJECT'): @property def hostname_checks_common_name(self): ncs = self._host_flags & _ssl.HOSTFLAG_NEVER_CHECK_SUBJECT return ncs != _ssl.HOSTFLAG_NEVER_CHECK_SUBJECT @hostname_checks_common_name.setter def hostname_checks_common_name(self, value): if value: self._host_flags &= ~_ssl.HOSTFLAG_NEVER_CHECK_SUBJECT else: self._host_flags |= _ssl.HOSTFLAG_NEVER_CHECK_SUBJECT else: @property def hostname_checks_common_name(self): return True @property def protocol(self): return _SSLMethod(super().protocol) @property def verify_flags(self): return VerifyFlags(super().verify_flags) @verify_flags.setter def verify_flags(self, value): super(SSLContext, SSLContext).verify_flags.__set__(self, value) @property def verify_mode(self): value = super().verify_mode try: return VerifyMode(value) except ValueError: return value @verify_mode.setter def verify_mode(self, value): super(SSLContext, SSLContext).verify_mode.__set__(self, value)
[docs]def create_default_context(purpose=Purpose.SERVER_AUTH, *, cafile=None, capath=None, cadata=None): """Create a SSLContext object with default settings. NOTE: The protocol and settings may change anytime without prior deprecation. The values represent a fair balance between maximum compatibility and security. """ if not isinstance(purpose, _ASN1Object): raise TypeError(purpose) # SSLContext sets OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION, # OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE and OP_SINGLE_ECDH_USE # by default. context = SSLContext(PROTOCOL_TLS) if purpose == Purpose.SERVER_AUTH: # verify certs and host name in client mode context.verify_mode = CERT_REQUIRED context.check_hostname = True if cafile or capath or cadata: context.load_verify_locations(cafile, capath, cadata) elif context.verify_mode != CERT_NONE: # no explicit cafile, capath or cadata but the verify mode is # CERT_OPTIONAL or CERT_REQUIRED. Let's try to load default system # root CA certificates for the given purpose. This may fail silently. context.load_default_certs(purpose) return context
def _create_unverified_context(protocol=PROTOCOL_TLS, *, cert_reqs=CERT_NONE, check_hostname=False, purpose=Purpose.SERVER_AUTH, certfile=None, keyfile=None, cafile=None, capath=None, cadata=None): """Create a SSLContext object for Python stdlib modules All Python stdlib modules shall use this function to create SSLContext objects in order to keep common settings in one place. The configuration is less restrict than create_default_context()'s to increase backward compatibility. """ if not isinstance(purpose, _ASN1Object): raise TypeError(purpose) # SSLContext sets OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION, # OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE and OP_SINGLE_ECDH_USE # by default. context = SSLContext(protocol) if not check_hostname: context.check_hostname = False if cert_reqs is not None: context.verify_mode = cert_reqs if check_hostname: context.check_hostname = True if keyfile and not certfile: raise ValueError("certfile must be specified") if certfile or keyfile: context.load_cert_chain(certfile, keyfile) # load CA root certs if cafile or capath or cadata: context.load_verify_locations(cafile, capath, cadata) elif context.verify_mode != CERT_NONE: # no explicit cafile, capath or cadata but the verify mode is # CERT_OPTIONAL or CERT_REQUIRED. Let's try to load default system # root CA certificates for the given purpose. This may fail silently. context.load_default_certs(purpose) return context # Used by http.client if no context is explicitly passed. _create_default_https_context = create_default_context # Backwards compatibility alias, even though it's not a public name. _create_stdlib_context = _create_unverified_context
[docs]class SSLObject: """This class implements an interface on top of a low-level SSL object as implemented by OpenSSL. This object captures the state of an SSL connection but does not provide any network IO itself. IO needs to be performed through separate "BIO" objects which are OpenSSL's IO abstraction layer. This class does not have a public constructor. Instances are returned by ``SSLContext.wrap_bio``. This class is typically used by framework authors that want to implement asynchronous IO for SSL through memory buffers. When compared to ``SSLSocket``, this object lacks the following features: * Any form of network IO, including methods such as ``recv`` and ``send``. * The ``do_handshake_on_connect`` and ``suppress_ragged_eofs`` machinery. """ def __init__(self, *args, **kwargs): raise TypeError( f"{self.__class__.__name__} does not have a public " f"constructor. Instances are returned by SSLContext.wrap_bio()." ) @classmethod def _create(cls, incoming, outgoing, server_side=False, server_hostname=None, session=None, context=None): self = cls.__new__(cls) sslobj = context._wrap_bio( incoming, outgoing, server_side=server_side, server_hostname=server_hostname, owner=self, session=session ) self._sslobj = sslobj return self @property def context(self): """The SSLContext that is currently in use.""" return self._sslobj.context @context.setter def context(self, ctx): self._sslobj.context = ctx @property def session(self): """The SSLSession for client socket.""" return self._sslobj.session @session.setter def session(self, session): self._sslobj.session = session @property def session_reused(self): """Was the client session reused during handshake""" return self._sslobj.session_reused @property def server_side(self): """Whether this is a server-side socket.""" return self._sslobj.server_side @property def server_hostname(self): """The currently set server hostname (for SNI), or ``None`` if no server hostame is set.""" return self._sslobj.server_hostname
[docs] def read(self, len=1024, buffer=None): """Read up to 'len' bytes from the SSL object and return them. If 'buffer' is provided, read into this buffer and return the number of bytes read. """ if buffer is not None: v = self._sslobj.read(len, buffer) else: v = self._sslobj.read(len) return v
[docs] def write(self, data): """Write 'data' to the SSL object and return the number of bytes written. The 'data' argument must support the buffer interface. """ return self._sslobj.write(data)
[docs] 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. """ return self._sslobj.getpeercert(binary_form)
[docs] def selected_npn_protocol(self): """Return the currently selected NPN protocol as a string, or ``None`` if a next protocol was not negotiated or if NPN is not supported by one of the peers.""" if _ssl.HAS_NPN: return self._sslobj.selected_npn_protocol()
[docs] def selected_alpn_protocol(self): """Return the currently selected ALPN protocol as a string, or ``None`` if a next protocol was not negotiated or if ALPN is not supported by one of the peers.""" if _ssl.HAS_ALPN: return self._sslobj.selected_alpn_protocol()
[docs] def cipher(self): """Return the currently selected cipher as a 3-tuple ``(name, ssl_version, secret_bits)``.""" return self._sslobj.cipher()
[docs] def shared_ciphers(self): """Return a list of ciphers shared by the client during the handshake or None if this is not a valid server connection. """ return self._sslobj.shared_ciphers()
[docs] def compression(self): """Return the current compression algorithm in use, or ``None`` if compression was not negotiated or not supported by one of the peers.""" return self._sslobj.compression()
[docs] def pending(self): """Return the number of bytes that can be read immediately.""" return self._sslobj.pending()
[docs] def do_handshake(self): """Start the SSL/TLS handshake.""" self._sslobj.do_handshake()
[docs] def unwrap(self): """Start the SSL shutdown handshake.""" return self._sslobj.shutdown()
[docs] 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).""" return self._sslobj.get_channel_binding(cb_type)
[docs] def version(self): """Return a string identifying the protocol version used by the current SSL channel. """ return self._sslobj.version()
def verify_client_post_handshake(self): return self._sslobj.verify_client_post_handshake()
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, *args, **kwargs): raise TypeError( f"{self.__class__.__name__} does not have a public " f"constructor. Instances are returned by " f"SSLContext.wrap_socket()." ) @classmethod def _create(cls, sock, server_side=False, do_handshake_on_connect=True, suppress_ragged_eofs=True, server_hostname=None, context=None, session=None): if sock.getsockopt(SOL_SOCKET, SO_TYPE) != SOCK_STREAM: raise NotImplementedError("only stream sockets are supported") if server_side: if server_hostname: raise ValueError("server_hostname can only be specified " "in client mode") if session is not None: raise ValueError("session can only be specified in " "client mode") if context.check_hostname and not server_hostname: raise ValueError("check_hostname requires server_hostname") kwargs = dict( family=sock.family, type=sock.type, proto=sock.proto, fileno=sock.fileno() ) self = cls.__new__(cls, **kwargs) super(SSLSocket, self).__init__(**kwargs) self.settimeout(sock.gettimeout()) sock.detach() self._context = context self._session = session self._closed = False self._sslobj = None self.server_side = server_side self.server_hostname = context._encode_hostname(server_hostname) self.do_handshake_on_connect = do_handshake_on_connect self.suppress_ragged_eofs = suppress_ragged_eofs # See if we are connected try: self.getpeername() except OSError as e: if e.errno != errno.ENOTCONN: raise connected = False else: connected = True self._connected = connected if connected: # create the SSL object try: self._sslobj = self._context._wrap_socket( self, server_side, self.server_hostname, owner=self, session=self._session, ) 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, ValueError): self.close() raise return self @property def context(self): return self._context @context.setter def context(self, ctx): self._context = ctx self._sslobj.context = ctx @property def session(self): """The SSLSession for client socket.""" if self._sslobj is not None: return self._sslobj.session @session.setter def session(self, session): self._session = session if self._sslobj is not None: self._sslobj.session = session @property def session_reused(self): """Was the client session reused during handshake""" if self._sslobj is not None: return self._sslobj.session_reused def dup(self): raise NotImplementedError("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=1024, buffer=None): """Read up to LEN bytes and return them. Return zero-length string on EOF.""" self._checkClosed() if self._sslobj is None: raise ValueError("Read on closed or unwrapped SSL socket.") try: if buffer is not None: return self._sslobj.read(len, buffer) else: return self._sslobj.read(len) 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 self._sslobj is None: 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.getpeercert(binary_form) def selected_npn_protocol(self): self._checkClosed() if self._sslobj is None or not _ssl.HAS_NPN: return None else: return self._sslobj.selected_npn_protocol() def selected_alpn_protocol(self): self._checkClosed() if self._sslobj is None or not _ssl.HAS_ALPN: return None else: return self._sslobj.selected_alpn_protocol() def cipher(self): self._checkClosed() if self._sslobj is None: return None else: return self._sslobj.cipher() def shared_ciphers(self): self._checkClosed() if self._sslobj is None: return None else: return self._sslobj.shared_ciphers() def compression(self): self._checkClosed() if self._sslobj is None: return None else: return self._sslobj.compression() def send(self, data, flags=0): self._checkClosed() if self._sslobj is not None: if flags != 0: raise ValueError( "non-zero flags not allowed in calls to send() on %s" % self.__class__) return self._sslobj.write(data) else: return super().send(data, flags) def sendto(self, data, flags_or_addr, addr=None): self._checkClosed() if self._sslobj is not None: raise ValueError("sendto not allowed on instances of %s" % self.__class__) elif addr is None: return super().sendto(data, flags_or_addr) else: return super().sendto(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 is not None: if flags != 0: raise ValueError( "non-zero flags not allowed in calls to sendall() on %s" % self.__class__) count = 0 with memoryview(data) as view, view.cast("B") as byte_view: amount = len(byte_view) while count < amount: v = self.send(byte_view[count:]) count += v else: return super().sendall(data, flags) def sendfile(self, file, offset=0, count=None): """Send a file, possibly by using os.sendfile() if this is a clear-text socket. Return the total number of bytes sent. """ if self._sslobj is not None: return self._sendfile_use_send(file, offset, count) else: # os.sendfile() works with plain sockets only return super().sendfile(file, offset, count) def recv(self, buflen=1024, flags=0): self._checkClosed() if self._sslobj is not None: if flags != 0: raise ValueError( "non-zero flags not allowed in calls to recv() on %s" % self.__class__) return self.read(buflen) else: return super().recv(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 is not None: 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 super().recv_into(buffer, nbytes, flags) def recvfrom(self, buflen=1024, flags=0): self._checkClosed() if self._sslobj is not None: raise ValueError("recvfrom not allowed on instances of %s" % self.__class__) else: return super().recvfrom(buflen, flags) def recvfrom_into(self, buffer, nbytes=None, flags=0): self._checkClosed() if self._sslobj is not None: raise ValueError("recvfrom_into not allowed on instances of %s" % self.__class__) else: return super().recvfrom_into(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 is not None: return self._sslobj.pending() else: return 0 def shutdown(self, how): self._checkClosed() self._sslobj = None super().shutdown(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 verify_client_post_handshake(self): if self._sslobj: return self._sslobj.verify_client_post_handshake() else: raise ValueError("No SSL wrapper around " + str(self)) def _real_close(self): self._sslobj = None super()._real_close() 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 or self._sslobj is not None: raise ValueError("attempt to connect already-connected SSLSocket!") self._sslobj = self.context._wrap_socket( self, False, self.server_hostname, owner=self, session=self._session ) try: if connect_ex: rc = super().connect_ex(addr) else: rc = None super().connect(addr) if not rc: self._connected = True if self.do_handshake_on_connect: self.do_handshake() return rc except (OSError, ValueError): 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 = super().accept() 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 self._sslobj is not None: return self._sslobj.get_channel_binding(cb_type) else: if cb_type not in CHANNEL_BINDING_TYPES: raise ValueError( "{0} channel binding type not implemented".format(cb_type) ) return None def version(self): """ Return a string identifying the protocol version used by the current SSL channel, or None if there is no established channel. """ if self._sslobj is not None: return self._sslobj.version() else: return None # Python does not support forward declaration of types. SSLContext.sslsocket_class = SSLSocket SSLContext.sslobject_class = SSLObject def wrap_socket(sock, keyfile=None, certfile=None, server_side=False, cert_reqs=CERT_NONE, ssl_version=PROTOCOL_TLS, ca_certs=None, do_handshake_on_connect=True, suppress_ragged_eofs=True, ciphers=None): 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") context = SSLContext(ssl_version) context.verify_mode = cert_reqs if ca_certs: context.load_verify_locations(ca_certs) if certfile: context.load_cert_chain(certfile, keyfile) if ciphers: context.set_ciphers(ciphers) return context.wrap_socket( sock=sock, server_side=server_side, do_handshake_on_connect=do_handshake_on_connect, suppress_ragged_eofs=suppress_ragged_eofs ) # some utility functions
[docs]def cert_time_to_seconds(cert_time): """Return the time in seconds since the Epoch, given the timestring representing the "notBefore" or "notAfter" date from a certificate in ``"%b %d %H:%M:%S %Y %Z"`` strptime format (C locale). "notBefore" or "notAfter" dates must use UTC (RFC 5280). Month is one of: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec UTC should be specified as GMT (see ASN1_TIME_print()) """ from time import strptime from calendar import timegm months = ( "Jan","Feb","Mar","Apr","May","Jun", "Jul","Aug","Sep","Oct","Nov","Dec" ) time_format = ' %d %H:%M:%S %Y GMT' # NOTE: no month, fixed GMT try: month_number = months.index(cert_time[:3].title()) + 1 except ValueError: raise ValueError('time data %r does not match ' 'format "%%b%s"' % (cert_time, time_format)) else: # found valid month tt = strptime(cert_time[3:], time_format) # return an integer, the previous mktime()-based implementation # returned a float (fractional seconds are always zero here). return timegm((tt[0], month_number) + tt[2:6])
PEM_HEADER = "-----BEGIN CERTIFICATE-----" PEM_FOOTER = "-----END CERTIFICATE-----"
[docs]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') ss = [PEM_HEADER] ss += [f[i:i+64] for i in range(0, len(f), 64)] ss.append(PEM_FOOTER + '\n') return '\n'.join(ss)
[docs]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_TLS, 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 context = _create_stdlib_context(ssl_version, cert_reqs=cert_reqs, cafile=ca_certs) with create_connection(addr) as sock: with context.wrap_socket(sock) as sslsock: dercert = sslsock.getpeercert(True) return DER_cert_to_PEM_cert(dercert) def get_protocol_name(protocol_code): return _PROTOCOL_NAMES.get(protocol_code, '<unknown>')