Re: [MASSMAIL][Pound Mailing List] openssl/Windows 2003/Secure Renegotiation

Correction, I only need to comment out the line with 
"SSL_OP_LEGACY_SERVER_CONNECT" to make openssl v1.0.1e work with Windows 
2003 server.  Also, we're using IIS6 as our web server on the windows boxes.


On 1/4/2015 11:14 AM, Albert wrote:
> I'm trying to migrated pound from an older load balancer to a new 
> machine, and ran into a problem connecting via HTTPS to a backend 
> server running Windows 2003. In my log files, I was seeing this error:
>
> Jan  2 15:28:42 pound: BIO_do_handshake with <Win2003webserver>:443 
> failed: error:1412F152:SSL 
> routines:SSL_PARSE_SERVERHELLO_TLSEXT:unsafe legacy renegotiation disabled
>
> This error was only happening for Win 2003 servers, and not Win 2008.  
> Pound versions were the same (2.7d), but CentOS & openssl are 
> different, as follows:
>
> Old server: Linux 2.6.18-371.12.1.el5 (CentOS 5.11), OpenSSL 
> 0.9.8e-fips-rhel5 01 Jul 2008
> New Server: Linux 3.10.0-123.13.2.el7.x86_64 (CentOS 7.0.1406), 
> OpenSSL 1.0.1e-fips 11 Feb 2013
>
> I also ran some diagnostics using openssl command, as follows:
>  openssl s_client -no_legacy_server_connect -connect <myserver>:443
>
> On Linux 2.6, I got "Secure Renegotiation IS supported", and 
> connection left open. Where on Linux 3.0, I received "Secure 
> Renegotiation IS NOT supported", and connection closed.  If I remove 
> "-no_legacy_server_connect" from Linux 3.0 call, it keeps the 
> connection open.  Also, running openssl against Win2008 on Linux 3.0 
> returns "Secure Renegotiation IS supported", so Win2008 is OK.
>
> So, this looked like an openssl option, which was introduced in v1.0, 
> so I tracked down a problem to couple of openssl options being cleared 
> in config.c (I'm looking at Pound 2.7 branch) :
>
> SSL_CTX_clear_options(res->ctx, SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION);
> SSL_CTX_clear_options(res->ctx, SSL_OP_LEGACY_SERVER_CONNECT);
>
> I have a 2 part question:
> 1. Does anybody know if Win 2003 can support Secure Renegotiation?
> 2. Is there a reason why Pound would set these options to a backend 
> (or at least not make these optional)?  I understand that there are 
> different vulnerabilities with web servers if these setting are set, 
> but this is being done on internal machines, not client-facing. 
> Additionally, these can be set when a client connects to pound via 
> SSLAllowClientRenegotiation in HTTPS Listener (though, as 
> documentation describes, this might leave your server to DoS exploits 
> and other vulnerabilities).
>
> I'd rather find a patch for Win2003 (if there is one), and leave the 
> pound code the same (currently, I have commented out the 2 lines from 
> above, and able to connect to Win2003).  But if there are none, should 
> pound allow connections to backends that don't support secure 
> renegotiations?
>
> Albert