fix #479

libmproxy/proxy/server.py

@@ -285,6 +285,11 @@ class ConnectionHandler:
 
             if sni != self.server_conn.sni:
                 self.log("SNI received: %s" % sni, "debug")
+                # We should only re-establish upstream SSL if one of the following conditions is true:
+                #   - We established SSL with the server previously
+                #   - We initially wanted to establish SSL with the server,
+                #     but the server refused to negotiate without SNI.
+                if self.server_conn.ssl_established or hasattr(self.server_conn, "may_require_sni"):
                     self.server_reconnect(sni)  # reconnect to upstream server with SNI
                 # Now, change client context to reflect changed certificate:
                 cert, key, chain_file = self.find_cert()

test/test_server.py

@@ -1,5 +1,6 @@
 import socket, time
 from libmproxy.proxy.config import HostMatcher
+import libpathod
 from netlib import tcp, http_auth, http
 from libpathod import pathoc, pathod
 from netlib.certutils import SSLCert
@@ -332,6 +333,36 @@ class TestReverse(tservers.ReverseProxTest, CommonMixin, TcpMixin):
     reverse = True
 
 
+class TestHttps2Http(tservers.ReverseProxTest):
+    @classmethod
+    def get_proxy_config(cls):
+        d = super(TestHttps2Http, cls).get_proxy_config()
+        d["upstream_server"][0] = True
+        return d
+
+    def pathoc(self, ssl, sni=None):
+        """
+            Returns a connected Pathoc instance.
+        """
+        p = libpathod.pathoc.Pathoc(("localhost", self.proxy.port), ssl=ssl, sni=sni)
+        p.connect()
+        return p
+
+    def test_all(self):
+        p = self.pathoc(ssl=True)
+        assert p.request("get:'/p/200'").status_code == 200
+
+    def test_sni(self):
+        p = self.pathoc(ssl=True, sni="example.com")
+        assert p.request("get:'/p/200'").status_code == 200
+        assert all("Error in handle_sni" not in msg for msg in self.proxy.log)
+
+    def test_http(self):
+        p = self.pathoc(ssl=False)
+        assert p.request("get:'/p/200'").status_code == 400
+
+
+
 class TestTransparent(tservers.TransparentProxTest, CommonMixin, TcpMixin):
     ssl = False
 

test/tservers.py

@@ -218,12 +218,12 @@ class ReverseProxTest(ProxTestBase):
     @classmethod
     def get_proxy_config(cls):
         d = ProxTestBase.get_proxy_config()
-        d["upstream_server"] = (
+        d["upstream_server"] = [
             True if cls.ssl else False,
             True if cls.ssl else False,
             "127.0.0.1",
             cls.server.port
-        )
+        ]
         d["mode"] = "reverse"
         return d