Bug 231853

Description of problem: 

We've found a replicable situation where pppd causes a kernel crash. First of 
all a bit of framework. 

We use pppd to provide remote support to some of our customers. Every customer 
has a personal account to connect to our server using PPP. The firewall on 
these accounts is configured so that we can connect back to their servers and 
check for problems, but the remote server has basicly no access at all to our 
network.

Since few weeks one of these customers caught a virus or a dialer (it uses a 
windows based server) which tries to connect to our server using the RAS entry 
configured for remote support, probably thinking it is an Internet connection. 
The RAS entry has the password saved, so that the virus is able to authenticate 
against our server, even though it isn't able to do anything else because of 
the configured firewall.

So far nothing wrong, by the way sometimes the virus is able to bring our 
server down because of a kernel crash. I haven't been able to save the kernel 
OOPS on screen but it clearly reported that the problem was caused by ppp. I 
have a log of the debug PPP session as saved by pppd (see attachemnt). We will 
further investigate to try to identify the virus or the dialer and may be catch 
the kernel OOPS.

Version-Release number of selected component (if applicable): ppp 2.4.3-6.2.1, 
kernel-smp 2.6.17 1.2157_FC5

How reproducible: difficult to reproduce

Steps to Reproduce: you need an infected windows pc, more info to be gathered
  
Actual results: kernel crash

Expected results: normal connection but no kernel crash and everything filtered 
out by the firewall

Additional info: none