Re: More on LIST_DELETE message with kernels 2.4.23 through 2.4.25

[Vijaya Chandra Vupputuri <vijay@tachyontech.net>]

Hi,
I was lazy enough to send a mail to the list instead of rebooting my
test box with a 2.4.23 kernel ;) ('ve had actually disabled conntrack
for the 2.4.23 kernel, so i'd done the test previously only with the
default redhat kernel)

This time with 2.4.23, after trying to make the local connection, I
tried viewing the conntrack entries (/proc/net/ip_conntrack) and the
system happily crashed.

Regards,
Vijaya Chandra Vupputuri,
Tachyon Technologies.

On Wed, 2004-03-17 at 16:46, KOVACS Krisztian wrote:
>   Hi,
> 
> On Wed, 2004-03-17 at 10:38, Vijaya Chandra Vupputuri wrote:
> > 've tried to do the same but I don't seem to have any problem on a test
> > box with redhat 7.3 (2.4.18-3)
> 
>   I think the problem is present only on kernels > 2.4.22. This is
> because of a fix in 2.4.23 which changed when alloc_null_binding() is
> called. In 2.4.22, alloc_null_binding() is called even when
> CONFIG_IP_NF_LOCAL_NAT is off, while in 2.4.23 (and above) it's only
> called when CONFIG_IP_NF_LOCAL_NAT is turned on. I don't know if it
> matters or not with respect to this problem.
> 
> > If I understood what you said properly the following is your setup,
> > the ip of the test box is 10.1.0.1 and you have a lan 10.1.0.0/16 whose
> > gateway is 10.1.0.1
> > on 10.1.0.1 you redirect any traffic to port 80 to the local port 8080
> 
>   Yes, this is the setup. (Although this is a virtual setup using UML,
> but it shouldn't matter at all.)
> 
> > now if 10.1.0.2 tries to connect to, say, 216.239.41.104 it gets
> > redirected to the port 8080 on 10.1.0.1
> 
>   Yes, in theory. To trigger the bug, you should connect _from_ the
> gateway to itself. (Note that the ruleset is somewhat flawed, since it
> should redirect only traffic coming in through the LAN interface.) I
> used netcat to connect:
> 
> # nc 10.1.0.1 80
> 
> > but, from 10.1.0.2, if you try to connect directly to port 80 on
> > 10.1.0.1, with your setup where nothing is listening on 80, the box
> > would hang. am i right?!
> 
>   It does not matter if there is something listening on port 80. I think
> it wasn't clear from my previous mail that you have to connect _from_
> the gateway, and not from the attached 10.1.0.0/16 LAN.