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Re: [reSIProcate] ACK relay question

Add that Route header pointed to this proxy and I think you're ok.

RjS

On Feb 1, 2007, at 10:45 AM, Scott Godin wrote:

Thanks Robert.  Actually we are record routing – but by the time the code checks if there is a Route header (in RequestContext)– we have already called RemoveTopRouteIfSelf.  Maybe I just need to fix it, so that it allows the ACK forwarding as long as there was a Route header, when we received the ACK.  Sound good?

 

Scott

 

From: Robert Sparks [mailto:rjsparks@xxxxxxxxxxx]
Sent: Thursday, February 01, 2007 11:02 AM
To: Scott Godin
Cc: Byron Campen; resiprocate-devel@xxxxxxxxxxxxxxxxxxxx
Subject: Re: [reSIProcate] ACK relay question

 

This is a security question - it is not unlike forwarding "stray" responses.

 

The risk protected against is primarily avoiding exhaustion of local resources (particularly TCP connections) with the extra spice of avoiding being used to anonymize traffic (example, circumvent firewall protection by appearing to come from a different source address) used in a DoS attack against someone else.

 

In your scenario, it appears you aren't record-routing, but the ACK is still showing up at repro? Do you have a need to not record-route?

 

If you want to enable building with different policies about such things, I think I'd rather have it involve a code change that selects the policy rather than a command-line option.

 

RjS

 

On Feb 1, 2007, at 9:23 AM, Scott Godin wrote:



Hi Byron,

 

You made the following comment RequestContext:

// !bwc! Someone is using us to relay an ACK, but host in

// From isn't ours, host in request-uri isn't ours, and no

// Route headers. Refusing to do so.

 

I’m curious why we have this code in repro – is this supposed to protect us from some sort of attack, or some security issues?

 

We have a case where we are modifying the From headers of requests sent through repro, in order to get the display on end UA’s the way we want it.  This chunk of code ends up dropping our ACKS if the domain in the from is not “owned” by repro.  Note:  it is common for the request uri to not match our domain, when routing using a mid-dialog request by using the contact header – since it is quite common to contain the ip address of the UA not the registered AOR.

 

I’m thinking of providing a command line option – something like “forward all ACKs”, in order to disable this checking.  Any concerns?

 

Scott

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