| 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 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 9 Sep 2008 22:11:33 +0200 From: Andi Kleen <andi@...stfloor.org> To: David Miller <davem@...emloft.net> Cc: andi@...stfloor.org, stephen.hemminger@...tta.com, eugeneteo@...nel.sg, netdev@...r.kernel.org, eteo@...hat.com Subject: Re: Internet-Draft on Port Randomisation On Tue, Sep 09, 2008 at 01:04:24PM -0700, David Miller wrote: > From: Andi Kleen <andi@...stfloor.org> > Date: Tue, 09 Sep 2008 16:28:30 +0200 > > > [haven't read the draft] But you don't necessarily need a full global > > lock for such a scheme. What works too is to access global state only > > ever N accesses and pre-allocate a small range per CPU. While there's > > still some global overhead then, it happens significantly less. My old > > alternative ipid setup algorithm worked this way. > > Should work well on a 64K cpu system. If you make N large enough it can work with pretty much any number of CPUs. The main drawback is that it's losing random bits the larger N is, but then 64k is not really remotely secure anyways. Due to the later reason I doubt such a change is very interesting. Also there's the issue on fully preemptible kernels. If you wanted a more secure port space what would like make more sense is to use IPv6 and use e.g. 32bit out of the local network address space for port randomization too. -Andi -- ak@...ux.intel.com -- 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