[Bridge] [RFC] bridge: STP timer management range checking

Alan Cox alan at lxorguk.ukuu.org.uk
Mon Sep 1 01:38:27 PDT 2008

> > Seems bogus extra code to me - stops things working that should be
> > allowed too.
> >   
> The timer configuration is propagated in network protocol, so 
> misconfigured Linux box
> could survive but effect other devices on the network that are less 
> robust. Maybe the

That would be irrelevant. CAP_NET_ADMIN lets you make that size mess

> small values would cause some other bridge to crash, go infinite loop, ...
> More likely robust devices might ignore our packets (because values out 
> of range), leading to
> routing loops and other disasters.

Spamming tree isn't secure, news at 11.

> The kernel does need to stop administrative settings from taking out a 
> network. 

If you have CAP_NET_ADMIN you can trivially take out the network unless
it is properly switched.

Now you might want your pretty little GUI and/or config tools to warn
people that their configuration is outside 802 specs but that is a
different matter altogether


More information about the Bridge mailing list