[Pkg-privacy-commits] [obfsproxy] 291/353: Clean up error handling when the http proxy doesn't return status.

[Ximin Luo]

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infinity0 pushed a commit to branch master
in repository obfsproxy.

commit a79b8ae6a147fdebc59e6555ad5e985487c47f94
Author: Yawning Angel <yawning at torproject.org>
Date:   Wed Apr 16 08:41:42 2014 +0000

    Clean up error handling when the http proxy doesn't return status.
    
    Some HTTP proxys opt to close the connection instead of returning a
    HTTP status code on certain failures (Eg: polipo auth faliure, privoxy
    ACL denial).  This change logs a better error message to the obfsproxy
    log when that happens.
    
    As an added bonus the SOCKS5 server now knows about EHOSTUNREACH, so
    a more informative response is sent on that failure type.
---
 obfsproxy/network/http.py   |  7 +++++--
 obfsproxy/network/socks5.py | 18 +++++++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/obfsproxy/network/http.py b/obfsproxy/network/http.py
index 9aa62d1..bdf0c8b 100644
--- a/obfsproxy/network/http.py
+++ b/obfsproxy/network/http.py
@@ -1,4 +1,5 @@
 from base64 import b64encode
+from twisted.internet.error import ConnectError
 from twisted.internet.interfaces import IStreamClientEndpoint
 from twisted.internet.protocol import ClientFactory
 from twisted.internet.defer import Deferred
@@ -57,7 +58,9 @@ class HTTPConnectClient(HTTPClient):
         if self.instance:
             self.instance.connectionLost(reason)
         else:
-            self.onConnectionError(reason)
+            # Some HTTP proxies (Eg: polipo) are rude and opt to close the
+            # connection instead of sending a status code indicating failure.
+            self.onConnectionError(ConnectError("Proxy connection closed during setup"))
 
     def handleEndHeaders(self):
         log.info("HTTPConnectClient: Connected to %s:%d via %s:%d" % (log.safe_addr_str(self.host), self.port, log.safe_addr_str(self.proxy_addr.host), self.proxy_addr.port))
@@ -73,7 +76,7 @@ class HTTPConnectClient(HTTPClient):
 
     def handleStatus(self, version, status, message):
         if status != "200":
-            self.onConnectionError(IOError("HTTPConnectClient: Proxy returned status: %s" % status))
+            self.onConnectionError(ConnectError("Proxy returned status: %s" % status))
 
     def rawDataReceived(self, data):
         log.debug("HTTPConnectClient: Received %d bytes of proxied data" % len(data))
diff --git a/obfsproxy/network/socks5.py b/obfsproxy/network/socks5.py
index 5cc62a2..02b4934 100644
--- a/obfsproxy/network/socks5.py
+++ b/obfsproxy/network/socks5.py
@@ -418,12 +418,28 @@ class SOCKSv5Protocol(protocol.Protocol):
             self.sendReply(SOCKSv5Reply.TTLExpired)
         elif failure.type == error.UnsupportedAddressFamily:
             self.sendReply(SOCKSv5Reply.AddressTypeNotSupported)
+        elif failure.type == error.ConnectError:
+            # Twisted doesn't have a exception defined for EHOSTUNREACH,
+            # so the failure is a ConnectError.  Try to catch this case
+            # and send a better reply, but fall back to a GeneralFailure.
+            reply = SOCKSv5Reply.GeneralFailure
+            try:
+                import errno
+                if hasattr(errno, "EHOSTUNREACH"):
+                    if failure.value.osError == errno.EHOSTUNREACH:
+                        reply = SOCKSv5Reply.HostUnreachable
+                if hasattr(errno, "WSAEHOSTUNREACH"):
+                    if failure.value.osError == errno.WSAEHOSTUNREACH:
+                        reply = SOCKSv5Reply.HostUnreachable
+            except Exception:
+                pass
+            self.sendReply(reply)
         else:
             self.sendReply(SOCKSv5Reply.GeneralFailure)
 
         failure.trap(error.NoRouteError, error.ConnectionRefusedError,
                      error.TCPTimedOutError, error.TimeoutError,
-                     error.UnsupportedAddressFamily)
+                     error.UnsupportedAddressFamily, error.ConnectError)
 
     def processCmdBind(self, addr, port):
         self.sendReply(SOCKSv5Reply.CommandNotSupported)

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