API

Note

The APIs for RFC 6125 verification beyond DNS-IDs (i.e. hostnames) aren’t public yet. They are in place and used by the documented high-level APIs though. Eventually they will become public. If you’d like to play with them and provide feedback have a look at the verify_service_identity function in the _common module.

service_identity.pyopenssl.verify_hostname(connection, hostname)

Verify whether the certificate of connection is valid for hostname.

Parameters:

• connection (OpenSSL.SSL.Connection) – A pyOpenSSL connection object.
• hostname (unicode) – The hostname that connection should be connected to.

Raises:

• service_identity.VerificationError – If connection does not provide a certificate that is valid for hostname.
• service_identity.CertificateError – If the certificate chain of connection contains a certificate that contains invalid/unexpected data.

Returns:

None

In practice, this may look like the following:

from __future__ import absolute_import, division, print_function

import socket

from OpenSSL import SSL
from service_identity import VerificationError
from service_identity.pyopenssl import verify_hostname


ctx = SSL.Context(SSL.SSLv23_METHOD)
ctx.set_verify(SSL.VERIFY_PEER, lambda conn, cert, errno, depth, ok: ok)
ctx.set_default_verify_paths()

hostname = u"twistedmatrix.com"
conn = SSL.Connection(ctx, socket.socket(socket.AF_INET, socket.SOCK_STREAM))
conn.connect((hostname, 443))

try:
   conn.do_handshake()
   verify_hostname(conn, hostname)
   # Do your super-secure stuff here.
except SSL.Error as e:
   print("TLS Handshake failed: {0!r}.".format(e.args[0]))
except VerificationError:
   print("Presented certificate is not valid for {0}.".format(hostname))
finally:
   conn.shutdown()
   conn.close()

exception service_identity.VerificationError

Verification failed.

exception service_identity.CertificateError

A certificate contains invalid or unexpected data.