Use ssl to verify hostname

This commit re-uses python 3's `ssl.match_hostname()` function to validate
hostname instead of relying on home grown algorithm.

package_control/http/validating_https_connection.py

@@ -1,7 +1,6 @@
 import base64
 import hashlib
 import os
-import re
 import socket
 import ssl
 
@@ -73,38 +72,6 @@ def __init__(self, host, port=None, ca_certs=None, extra_ca_certs=None, **kwargs
 
         self._context = context
 
-    def get_valid_hosts_for_cert(self, cert):
-        """
-        Returns a list of valid hostnames for an SSL certificate
-
-        :param cert: A dict from SSLSocket.getpeercert()
-
-        :return: An array of hostnames
-        """
-
-        if 'subjectAltName' in cert:
-            return [x[1] for x in cert['subjectAltName'] if x[0].lower() == 'dns']
-        else:
-            return [x[0][1] for x in cert['subject'] if x[0][0].lower() == 'commonname']
-
-    def validate_cert_host(self, cert, hostname):
-        """
-        Checks if the cert is valid for the hostname
-
-        :param cert: A dict from SSLSocket.getpeercert()
-
-        :param hostname: A string hostname to check
-
-        :return: A boolean if the cert is valid for the hostname
-        """
-
-        hosts = self.get_valid_hosts_for_cert(cert)
-        for host in hosts:
-            host_re = host.replace('.', r'\.').replace('*', r'[^.]*')
-            if re.search('^%s$' % (host_re,), hostname, re.I):
-                return True
-        return False
-
     # Compatibility for python 3.3 vs 3.8
     #   python 3.8 replaced _set_hostport() by _get_hostport()
     if not hasattr(DebuggableHTTPConnection, '_set_hostport'):
@@ -393,11 +360,13 @@ def connect(self):
                 if 'notAfter' in cert:
                     console_write('    expire date: %s', cert['notAfter'], prefix=False)
 
-            if not self.validate_cert_host(cert, hostname):
+            try:
+                ssl.match_hostname(cert, hostname)
                 if self.debuglevel == -1:
-                    console_write('  Certificate INVALID', prefix=False)
+                    console_write('  Certificate validated for %s', hostname, prefix=False)
 
-                raise InvalidCertificateException(hostname, cert, 'hostname mismatch')
+            except ssl.CertificateError as e:
+                if self.debuglevel == -1:
+                    console_write('  Certificate INVALID: %s', e, prefix=False)
 
-            if self.debuglevel == -1:
-                console_write('  Certificate validated for %s', hostname, prefix=False)
+                raise InvalidCertificateException(hostname, cert, e)