On Tue, 28 Feb 2006 14:29:30 -0500
Jeff Garzik <[EMAIL PROTECTED]> wrote:
> Stephen Hemminger wrote:
> > On Tue, 28 Feb 2006 13:56:57 -0500
> > Jeff Garzik <[EMAIL PROTECTED]> wrote:
> >
> >
> >>Stephen Hemminger wrote:
> >>
> >>>This trivial patch can go in the netdev can for 2.6.17.
> >>>It lets skge driver contribute to random entropy poll.
> >>>
> >>>Signed-off-by: Stephen Hemminger <[EMAIL PROTECTED]>
> >>>
> >>>--- sky2.orig/drivers/net/skge.c 2006-02-27 10:00:48.000000000 -0800
> >>>+++ sky2/drivers/net/skge.c 2006-02-28 10:35:48.000000000 -0800
> >>>@@ -3314,7 +3314,9 @@
> >>> goto err_out_free_hw;
> >>> }
> >>>
> >>>- if ((err = request_irq(pdev->irq, skge_intr, SA_SHIRQ, DRV_NAME, hw))) {
> >>>+ err = request_irq(pdev->irq, skge_intr, SA_SHIRQ | SA_SAMPLE_RANDOM,
> >>>+ DRV_NAME, hw);
> >>
> >>The traditional objection to this is that the sampling is _not_ random,
> >>if you are a remote attacker, carefully timing your packets...
> >>
> >>tg3 and e1000 do it, as does sky2, but I'm still not convinced its safe.
> >>
> >
> >
> > I guess the problem comes down to the resolution of the clock used
> > for sampling. Right now with 250hz, it isn't really fast to be a good
> > entropy source on any network card.
>
> Oh yeah, another aspect: cards with hardware interrupt mitigation
> should NOT use SA_SAMPLE_RANDOM, for obvious reasons... Anything that
> has the potential to have non-random timings should be avoided.
Then the skge, sky2, e1000, and tg3 should NOT be sampling.
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