lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Fri, 18 Jan 2008 21:57:00 -0800
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Stephen Hemminger <shemminger@...tta.com>
Cc:	Stephen Hemminger <stephen.hemminger@...tta.com>,
	David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH 1/3] sfq: timer is deferrable

On Fri, Jan 18, 2008 at 08:36:55PM -0800, Stephen Hemminger wrote:
> On Fri, 18 Jan 2008 20:34:46 -0800
> "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com> wrote:
> 
> > On Fri, Jan 18, 2008 at 02:49:00PM -0800, Stephen Hemminger wrote:
> > > The perturbation timer used for re-keying can be deferred, it doesn't
> > > need to be deterministic.
> > 
> > The only concern that I can come up with is that the sfq_perturbation
> > timer might be on one CPU, and all the operations using the corresponding
> > SFQ on another.  This could in theory allow a nearly omniscient attacker
> > to exploit an SFQ imbalance while preventing perturbation of the hash
> > function.
> > 
> > This does not seem to be a valid concern at this point, since there are
> > very few uses of init_timer_deferrable().  And if it should become a
> > problem, one approach would be to have some sort of per-timer limit to
> > the deferral.  Of course, at that point one would need to figure out
> > what this limit should be!
> > 
> > Acked-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> 
> But the only threat is getting more bandwidth for a longer interval.
> It is all kind of moot anyway because the bandwidth hogs all open
> multiple connections anyway, so SFQ is of no use.

Good point, and an additional reason for my Acked-by above.  ;-)

						Thanx, Paul
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists