Messages in this thread | | | Date | Mon, 8 Nov 2010 13:42:28 -0800 | From | Kees Cook <> | Subject | Re: [Security] proactive defense: using read-only memory, RO/NX modules |
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Hi,
On Mon, Nov 08, 2010 at 07:13:24AM +0100, Ingo Molnar wrote: > * Kees Cook <kees.cook@canonical.com> wrote: > > While Dan Rosenberg is working to make things harder to locate potential targets > > in the kernel through fixing kernel address leaks[1], I'd like to approach a > > related proactive security measure: enforcing read-only memory for things that > > would make good targets. > > Nice! IMHO we need more of that. (If the readonly section gets big enough in > practice we could perhaps even mark it large-page in the future. It could serve as > an allocator to module code as well - that would probably be a speedup even for > modules.)
Well, I can try to extract and send what PaX does, but it seems relatively incompatible with the existing system that uses set_kernel_text_rw() and friends.
> > - Modules need to be correctly marked RO/NX. This patch exists[3], but is > > not in mainline. It needs to be in mainline. > [...] > > > > [3] http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commitdiff;h=65187d24fa3ef60f691f847c792e8eaca7e19251 > > The reason the RO/NX patch from Siarhei Liakh is not upstream yet is rather mundane: > it introduced regressions - it caused boot crashes on one of my testboxes. > > But there is no fundamental reason why it shouldnt be upstream. We can push it > upstream if the crashes are resolved and if it gets an Ack from Rusty or Linus for > the module bits.
Oh, well, yes, that's a good reason. :) Where was this covered? I'd like to help get it reproduced and ironed out.
-Kees
-- Kees Cook Ubuntu Security Team
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