Re: AW: Re: AW: Re: VLAN and Network Drivers 2.4.x

Jeff Garzik
2002-04-24T17:49:37Z

On Wed, Apr 24, 2002 at 10:31:29AM -0700, Ben Greear wrote:
> Also, is there any good reason that we can't get at least a compile
> time change into some of the drivers like tulip where we know we can
> get at least MOST of the cards supported with a small change?

The tulip patch is butt-ugly - the oversized allocation isn't needed,
and it just flat-out turns off large packet protection. That's really
not what you want to do, even for the best tulip cards. If an oversized
gram (non-VLAN) makes it into a network which such a patched tulip
driver, you can DoS. So, I view the current tulip patch as unacceptable
too -- for security reasons, we should not even take it as a compile
time patch. (and I recommend against using that patch on production
machines, for the same security reasons)

The proper tulip patch does not need to change packet allocation size
at all (it's already plenty big enough), and it needs to copy the RX
fragment handling code from 8139cp (which is admittedly ugly, slow path)
or write fresh fragment handling code. Along with that fragment
handling code comes a safe way to do VLAN, and non-standard large MTUs
in general.

> The same argument applies to the EEPRO driver (we know a cure, but it's
> a magic register number, and no one will accept the patch).

I think we have a good chance of making that a less magic-number patch,
though, given the last discussion.

Jeff