Bug 1000773

Summary: nc breaks on HTTP/1.1 proxy servers
Product: Red Hat Enterprise Linux 6 Reporter: Andreas M. Kirchwitz <amk>
Component: ncAssignee: Petr Šabata <psabata>
Status: CLOSED ERRATA QA Contact: Martin Žember <mzember>
Severity: medium Docs Contact:
Priority: medium    
Version: 6.4CC: ccheney, cww, ebenes, jorton, laxman.gawade, mzember, ptalbert, ruckc
Target Milestone: rcKeywords: Patch
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: nc-1.84-23.el6 Doc Type: Enhancement
Doc Text:
Feature: Netcat now understands HTTP/1.1 proxy responses. Reason: Some proxies send HTTP/1.1 responses to HTTP/1.0 requests. Netcat didn't understand these and was therefore unusuable in such situations. Result: Netcat now works with HTTP/1.1-only proxies.
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-12-08 09:08:02 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On:    
Bug Blocks: 1159820    

Description Andreas M. Kirchwitz 2013-08-25 03:20:20 UTC
Description of problem:
nc only supports HTTP/1.0 proxy servers and fails on HTTP/1.1 responses.

$ nc -X connect -x proxy.example.com:3128 www.example.com 443
nc: Proxy error: "HTTP/1.1 200 Connection established"

nc works fine without proxy or with HTTP/1.0 proxy servers, but with recent versions of Squid (always sending HTTP/1.1 responses) it fails. Proxy servers must send the highest HTTP version they support (not necessarily the same as the version of the original request).

If you look into the source code, nc expects a hardcoded "HTTP/1.0 200 " response. It shouldn't care about the HTTP version as long as it gets a positive "200" response.

Version-Release number of selected component (if applicable):

How reproducible:
Use nc to connect through a HTTP/1.1 proxy.

Steps to Reproduce:
1. see above

Actual results:
nc aborts because of hardcoded HTTP version.

Expected results:
Happily connect and ignore the HTTP version (the "200" response is all that matters).

Additional info:
I could use "ncat" (nmap) instead but that has also an issue with HTTP proxy.

Comment 2 Petr Šabata 2013-08-26 08:50:51 UTC
This is an easy fix and already present upstream, too.

Comment 6 ruckc@yahoo.com 2014-05-29 13:12:50 UTC
This should be a trivial fix, please update from upstream.

Comment 10 Petr Šabata 2014-11-26 14:38:58 UTC
A fix pushed in nc-1.84-23.el6.

Comment 14 errata-xmlrpc 2014-12-08 09:08:02 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.