Make the certificate wait time configurable.

Since OpenSSL doesn't let us set certificate start times in the past, the
client and proxy machine time must be synchronized, or the client might reject
the certificate. We can bodgy over small discrepancies by waiting a few seconds
after a new certificate is generated (i.e. the first time an SSL domain is contacted).

Make this a configurable option, and turn it off by default.

libmproxy/cmdline.py

@@ -116,6 +116,12 @@ def common_options(parser):
     )
     parser.add_option_group(group)
 
+    parser.add_option(
+        "--cert-wait-time",
+        action="store", dest="cert_wait_time", default=0,
+        help="Wait for specified number of seconds after a new cert is generated. This can smooth over small discrepancies between the client and server times."
+    )
+
     group = optparse.OptionGroup(parser, "Server Replay")
     group.add_option(
         "-s",

libmproxy/proxy.py

@@ -23,11 +23,12 @@ class ProxyError(Exception):
 
 
 class SSLConfig:
-    def __init__(self, certfile = None, ciphers = None, cacert = None):
+    def __init__(self, certfile = None, ciphers = None, cacert = None, cert_wait_time=None):
         self.certfile = certfile
         self.ciphers = ciphers
         self.cacert = cacert
         self.certdir = None
+        self.cert_wait_time = cert_wait_time
 
 
 def read_chunked(fp):
@@ -613,6 +614,7 @@ class ProxyHandler(SocketServer.StreamRequestHandler):
             return self.config.certfile
         else:
             ret = utils.dummy_cert(self.config.certdir, self.config.cacert, host)
+            time.sleep(self.config.cert_wait_time)
             if not ret:
                 raise ProxyError(400, "mitmproxy: Unable to generate dummy cert.")
             return ret
@@ -784,5 +786,6 @@ def process_certificate_option_group(parser, options):
     return SSLConfig(
         certfile = options.cert,
         cacert = cacert,
-        ciphers = options.ciphers
+        ciphers = options.ciphers,
+        cert_wait_time = options.cert_wait_time
     )

libmproxy/utils.py

@@ -497,7 +497,6 @@ def dummy_cert(certdir, ca, commonname):
             stdin=subprocess.PIPE
         )
         if ret: return None
-    time.sleep(CERT_SLEEP_TIME)
     return certpath