Bugtraq mailing list archives

Re: OpenVPN[v2.0.x]: foreign_option() formart string vulnerability.


From: v9 <v9 () fakehalo us>
Date: Fri, 4 Nov 2005 15:46:45 -0500 (EST)

ah, that would be what i did when testing("client"), sorry for the
false/confusion with that... anyways, great software i use it for my vpn
needs...nicely documented and easy to use--thanks for its existence.

Vade79,

Thanks for your efforts in finding this!  I've just released OpenVPN 2.0.4
with a fix.

The patch is here:

http://openvpn.net/patch/2.0.4-security-patches/foreign_option.patch

While this patch fixes the format string vulnerability, you made another
claim as well which I believe to be false:

however, when testing i did NOT have to have the "pull" option in my clients config
file to allow the "push"ed dhcp-option request as it states above.

You didn't post your test configuration file, but I suspect that you were
using "client" which is a macro that expands to "pull" and "tls-client".

Take a look at this line in push.c:

if (honor_received_options && buf_string_compare_advance (&buf, "PUSH_REPLY"))

This conditional decides whether or not to process a received PUSH_REPLY
message.  honor_received_options will be false unless "pull" or "client"
is specified.

James




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