ssl.py

__ssl = __import__('ssl')

from eventlet.patcher import slurp_properties
slurp_properties(__ssl, globals(), srckeys=dir(__ssl))

import functools
import sys
import errno
time = __import__('time')

from eventlet.support import get_errno, PY33, six
from eventlet.hubs import trampoline, IOClosed
from eventlet.greenio import (
    set_nonblocking, GreenSocket, SOCKET_CLOSED, CONNECT_ERR, CONNECT_SUCCESS,
)
orig_socket = __import__('socket')
socket = orig_socket.socket
if sys.version_info >= (2, 7):
    has_ciphers = True
    timeout_exc = SSLError
else:
    has_ciphers = False
    timeout_exc = orig_socket.timeout

__patched__ = [
    'SSLSocket', 'SSLContext', 'wrap_socket', 'sslwrap_simple',
    'create_default_context', '_create_default_https_context']

_original_sslsocket = __ssl.SSLSocket


class GreenSSLSocket(_original_sslsocket):
    """ This is a green version of the SSLSocket class from the ssl module added
    in 2.6.  For documentation on it, please see the Python standard
    documentation.

    Python nonblocking ssl objects don't give errors when the other end
    of the socket is closed (they do notice when the other end is shutdown,
    though).  Any write/read operations will simply hang if the socket is
    closed from the other end.  There is no obvious fix for this problem;
    it appears to be a limitation of Python's ssl object implementation.
    A workaround is to set a reasonable timeout on the socket using
    settimeout(), and to close/reopen the connection when a timeout
    occurs at an unexpected juncture in the code.
    """
    # we are inheriting from SSLSocket because its constructor calls
    # do_handshake whose behavior we wish to override

    def __init__(self, sock, keyfile=None, certfile=None,
                 server_side=False, cert_reqs=CERT_NONE,
                 ssl_version=PROTOCOL_SSLv23, ca_certs=None,
                 do_handshake_on_connect=True, *args, **kw):
        if not isinstance(sock, GreenSocket):
            sock = GreenSocket(sock)

        self.act_non_blocking = sock.act_non_blocking

        if six.PY2:
            # On Python 2 SSLSocket constructor queries the timeout, it'd break without
            # this assignment
            self._timeout = sock.gettimeout()

        # nonblocking socket handshaking on connect got disabled so let's pretend it's disabled
        # even when it's on
        super(GreenSSLSocket, self).__init__(
            sock.fd, keyfile, certfile, server_side, cert_reqs, ssl_version,
            ca_certs, do_handshake_on_connect and six.PY2, *args, **kw)

        # the superclass initializer trashes the methods so we remove
        # the local-object versions of them and let the actual class
        # methods shine through
        # Note: This for Python 2
        try:
            for fn in orig_socket._delegate_methods:
                delattr(self, fn)
        except AttributeError:
            pass

        if six.PY3:
            # Python 3 SSLSocket construction process overwrites the timeout so restore it
            self._timeout = sock.gettimeout()

            # it also sets timeout to None internally apparently (tested with 3.4.2)
            _original_sslsocket.settimeout(self, 0.0)
            assert _original_sslsocket.gettimeout(self) == 0.0

            # see note above about handshaking
            self.do_handshake_on_connect = do_handshake_on_connect
            if do_handshake_on_connect and self._connected:
                self.do_handshake()

    def settimeout(self, timeout):
        self._timeout = timeout

    def gettimeout(self):
        return self._timeout

    def setblocking(self, flag):
        if flag:
            self.act_non_blocking = False
            self._timeout = None
        else:
            self.act_non_blocking = True
            self._timeout = 0.0

    def _call_trampolining(self, func, *a, **kw):
        if self.act_non_blocking:
            return func(*a, **kw)
        else:
            while True:
                try:
                    return func(*a, **kw)
                except SSLError as exc:
                    if get_errno(exc) == SSL_ERROR_WANT_READ:
                        trampoline(self,
                                   read=True,
                                   timeout=self.gettimeout(),
                                   timeout_exc=timeout_exc('timed out'))
                    elif get_errno(exc) == SSL_ERROR_WANT_WRITE:
                        trampoline(self,
                                   write=True,
                                   timeout=self.gettimeout(),
                                   timeout_exc=timeout_exc('timed out'))
                    else:
                        raise

    def write(self, data):
        """Write DATA to the underlying SSL channel.  Returns
        number of bytes of DATA actually transmitted."""
        return self._call_trampolining(
            super(GreenSSLSocket, self).write, data)

    def read(self, *args, **kwargs):
        """Read up to LEN bytes and return them.
        Return zero-length string on EOF."""
        try:
            return self._call_trampolining(
                super(GreenSSLSocket, self).read, *args, **kwargs)
        except IOClosed:
            return b''

    def send(self, data, flags=0):
        if self._sslobj:
            return self._call_trampolining(
                super(GreenSSLSocket, self).send, data, flags)
        else:
            trampoline(self, write=True, timeout_exc=timeout_exc('timed out'))
            return socket.send(self, data, flags)

    def sendto(self, data, addr, flags=0):
        # *NOTE: gross, copied code from ssl.py becase it's not factored well enough to be used as-is
        if self._sslobj:
            raise ValueError("sendto not allowed on instances of %s" %
                             self.__class__)
        else:
            trampoline(self, write=True, timeout_exc=timeout_exc('timed out'))
            return socket.sendto(self, data, addr, flags)

    def sendall(self, data, flags=0):
        # *NOTE: gross, copied code from ssl.py becase it's not factored well enough to be used as-is
        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
            data_to_send = data
            while (count < amount):
                v = self.send(data_to_send)
                count += v
                if v == 0:
                    trampoline(self, write=True, timeout_exc=timeout_exc('timed out'))
                else:
                    data_to_send = data[count:]
            return amount
        else:
            while True:
                try:
                    return socket.sendall(self, data, flags)
                except orig_socket.error as e:
                    if self.act_non_blocking:
                        raise
                    if get_errno(e) == errno.EWOULDBLOCK:
                        trampoline(self, write=True,
                                   timeout=self.gettimeout(), timeout_exc=timeout_exc('timed out'))
                    if get_errno(e) in SOCKET_CLOSED:
                        return ''
                    raise

    def recv(self, buflen=1024, flags=0):
        # *NOTE: gross, copied code from ssl.py becase it's not factored well enough to be used as-is
        if self._sslobj:
            if flags != 0:
                raise ValueError(
                    "non-zero flags not allowed in calls to recv() on %s" %
                    self.__class__)
            read = self.read(buflen)
            return read
        else:
            while True:
                try:
                    return socket.recv(self, buflen, flags)
                except orig_socket.error as e:
                    if self.act_non_blocking:
                        raise
                    if get_errno(e) == errno.EWOULDBLOCK:
                        try:
                            trampoline(
                                self, read=True,
                                timeout=self.gettimeout(), timeout_exc=timeout_exc('timed out'))
                        except IOClosed:
                            return b''
                    if get_errno(e) in SOCKET_CLOSED:
                        return b''
                    raise

    def recv_into(self, buffer, nbytes=None, flags=0):
        if not self.act_non_blocking:
            trampoline(self, read=True, timeout=self.gettimeout(),
                       timeout_exc=timeout_exc('timed out'))
        return super(GreenSSLSocket, self).recv_into(buffer, nbytes, flags)

    def recvfrom(self, addr, buflen=1024, flags=0):
        if not self.act_non_blocking:
            trampoline(self, read=True, timeout=self.gettimeout(),
                       timeout_exc=timeout_exc('timed out'))
        return super(GreenSSLSocket, self).recvfrom(addr, buflen, flags)

    def recvfrom_into(self, buffer, nbytes=None, flags=0):
        if not self.act_non_blocking:
            trampoline(self, read=True, timeout=self.gettimeout(),
                       timeout_exc=timeout_exc('timed out'))
        return super(GreenSSLSocket, self).recvfrom_into(buffer, nbytes, flags)

    def unwrap(self):
        return GreenSocket(self._call_trampolining(
            super(GreenSSLSocket, self).unwrap))

    def do_handshake(self):
        """Perform a TLS/SSL handshake."""
        return self._call_trampolining(
            super(GreenSSLSocket, self).do_handshake)

    def _socket_connect(self, addr):
        real_connect = socket.connect
        if self.act_non_blocking:
            return real_connect(self, addr)
        else:
            # *NOTE: gross, copied code from greenio because it's not factored
            # well enough to reuse
            if self.gettimeout() is None:
                while True:
                    try:
                        return real_connect(self, addr)
                    except orig_socket.error as exc:
                        if get_errno(exc) in CONNECT_ERR:
                            trampoline(self, write=True)
                        elif get_errno(exc) in CONNECT_SUCCESS:
                            return
                        else:
                            raise
            else:
                end = time.time() + self.gettimeout()
                while True:
                    try:
                        real_connect(self, addr)
                    except orig_socket.error as exc:
                        if get_errno(exc) in CONNECT_ERR:
                            trampoline(
                                self, write=True,
                                timeout=end - time.time(), timeout_exc=timeout_exc('timed out'))
                        elif get_errno(exc) in CONNECT_SUCCESS:
                            return
                        else:
                            raise
                    if time.time() >= end:
                        raise timeout_exc('timed out')

    def connect(self, addr):
        """Connects to remote ADDR, and then wraps the connection in
        an SSL channel."""
        # *NOTE: grrrrr copied this code from ssl.py because of the reference
        # to socket.connect which we don't want to call directly
        if self._sslobj:
            raise ValueError("attempt to connect already-connected SSLSocket!")
        self._socket_connect(addr)
        server_side = False
        try:
            sslwrap = _ssl.sslwrap
        except AttributeError:
            # sslwrap was removed in 3.x and later in 2.7.9
            if six.PY2:
                sslobj = self._context._wrap_socket(self._sock, server_side, ssl_sock=self)
            else:
                context = self.context if PY33 else self._context
                sslobj = context._wrap_socket(self, server_side)
        else:
            sslobj = sslwrap(self._sock, server_side, self.keyfile, self.certfile,
                             self.cert_reqs, self.ssl_version,
                             self.ca_certs, *([self.ciphers] if has_ciphers else []))

        self._sslobj = sslobj
        if self.do_handshake_on_connect:
            self.do_handshake()

    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."""
        # RDW grr duplication of code from greenio
        if self.act_non_blocking:
            newsock, addr = socket.accept(self)
        else:
            while True:
                try:
                    newsock, addr = socket.accept(self)
                    set_nonblocking(newsock)
                    break
                except orig_socket.error as e:
                    if get_errno(e) != errno.EWOULDBLOCK:
                        raise
                    trampoline(self, read=True, timeout=self.gettimeout(),
                               timeout_exc=timeout_exc('timed out'))

        new_ssl = type(self)(
            newsock,
            keyfile=self.keyfile,
            certfile=self.certfile,
            server_side=True,
            cert_reqs=self.cert_reqs,
            ssl_version=self.ssl_version,
            ca_certs=self.ca_certs,
            do_handshake_on_connect=self.do_handshake_on_connect,
            suppress_ragged_eofs=self.suppress_ragged_eofs)
        return (new_ssl, addr)

    def dup(self):
        raise NotImplementedError("Can't dup an ssl object")

SSLSocket = GreenSSLSocket


def wrap_socket(sock, *a, **kw):
    return GreenSSLSocket(sock, *a, **kw)


if hasattr(__ssl, 'sslwrap_simple'):
    def sslwrap_simple(sock, keyfile=None, certfile=None):
        """A replacement for the old socket.ssl function.  Designed
        for compatibility with Python 2.5 and earlier.  Will disappear in
        Python 3.0."""
        ssl_sock = GreenSSLSocket(sock, keyfile=keyfile, certfile=certfile,
                                  server_side=False,
                                  cert_reqs=CERT_NONE,
                                  ssl_version=PROTOCOL_SSLv23,
                                  ca_certs=None)
        return ssl_sock


if hasattr(__ssl, 'SSLContext'):
    _original_sslcontext = __ssl.SSLContext

    class GreenSSLContext(_original_sslcontext):
        __slots__ = ()

        def wrap_socket(self, sock, *a, **kw):
            return GreenSSLSocket(sock, *a, _context=self, **kw)

    SSLContext = GreenSSLContext

    if hasattr(__ssl, 'create_default_context'):
        _original_create_default_context = __ssl.create_default_context

        def green_create_default_context(*a, **kw):
            # We can't just monkey-patch on the green version of `wrap_socket`
            # on to SSLContext instances, but SSLContext.create_default_context
            # does a bunch of work. Rather than re-implementing it all, just
            # switch out the __class__ to get our `wrap_socket` implementation
            context = _original_create_default_context(*a, **kw)
            context.__class__ = GreenSSLContext
            return context

        create_default_context = green_create_default_context
        _create_default_https_context = green_create_default_context