Date: Mon, 18 Feb 2008 10:07:48 -0500 From: Wesley Shields <wxs@FreeBSD.org> To: Mark Andrews <Mark_Andrews@isc.org> Cc: Dag-Erling Sm?rgrav <des@des.no>, Jim Bryant <freebsd@electron-tube.net>, Kurt Buff <kurt.buff@gmail.com>, freebsd-security@freebsd.org Subject: Re: How to take down a system to the point of requiring a newfs with one line of C (userland) Message-ID: <20080218150748.GD90004@atarininja.org> In-Reply-To: <200802181414.m1IEE8bd075081@drugs.dv.isc.org> References: <a9f4a3860802180527k6fcfbdaeuf235540075b263b5@mail.gmail.com> <200802181414.m1IEE8bd075081@drugs.dv.isc.org>
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On Tue, Feb 19, 2008 at 01:14:08AM +1100, Mark Andrews wrote: > > > Patient: Doctor, it hurts when I do this! > > > > Doctor: Don't do that... > > Did you actually bother to read his report? > > While his example is used "/", if the report is correct then you > just need to replace "/" with the path of any file system mount > point that is world writable like say "/tmp". > > Do you have /tmp mounted like this? > /dev/ad0s4e 507630 162050 304970 35% /tmp > > Have you tried using "/tmp" or some other suitable mount point > before slinging off with the old Doctor joke? > > Even if it is only "/", having the system die and not be recoverable > due to having a excessive number of files in "/" is a critical > error. I'm sure you have *never* accidently copied a set of files > to "/" in your life. Me, I know I've made that sort of mistake in > the past, and as I'm not perfect, I'm sure I'll make that sort of > mistake at some point in the future. I would however like the > machine not to fallover when I do make that mistake. > > Now why don't you be constructive and verify whether the report is > valid or not. I don't have a spare machine to test it on so I'm > not going to attempt it. I tried this using /tmp/ as argv[1] and it didn't crash a 6.2 machine or a -current from a few weeks ago. Maybe the number of files has to be increased? I bumped it up to 100000 and tried on a 6.2 machine, but I ran out of inodes before I could induce a crash. :) Maybe I'm doing something wrong? -- WXShelp
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