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Date: Fri, 19 Nov 2010 11:58:20 -0800 (PST) From: david@...g.hm To: Linus Torvalds <torvalds@...ux-foundation.org> cc: Sarah Sharp <sarah.a.sharp@...ux.intel.com>, Marcus Meissner <meissner@...e.de>, linux-kernel@...r.kernel.org, tj@...nel.org, akpm@...ux-foundation.org, hpa@...or.com, mingo@...e.hu, w@....eu, alan@...rguk.ukuu.org.uk Subject: Re: [PATCH] kernel: make /proc/kallsyms mode 400 to reduce ease of attacking On Fri, 19 Nov 2010, Linus Torvalds wrote: > On Fri, Nov 19, 2010 at 11:19 AM, Sarah Sharp > <sarah.a.sharp@...ux.intel.com> wrote: >> >> .config and dmesg are attached. The box is running klogd 1.5.5ubuntu3 >> (from Jaunty). Yes, I know that's old. I read the bit in the commit >> about changing the permissions of kallsyms after boot, but if I can't >> boot that doesn't help. Perhaps this can be made a configuration >> option? > > It's not worth a config option. > > If it actually breaks user-space, I think we should just revert it. how far back do we need to maintain compatibility with userspace? Is this something that we can revisit in a few years and lock it down then? David Lang > It's kind of sad to default to the world-visible thing, but as I > mentioned in the commit, this is something where a sysadmin or distro > can trivially just fix it at boot-time too, with just a > > chmod og-r /proc/kallsyms > > in your bootup scripts. > > And if somebody has taken control of the machine _before_ the bootup > scripts get to run, you have bigger problems than a /proc/kallsyms > file. > > So I guess I'll revert it. > > Thanks for testing and bisecting. > > Linus > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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