Messages in this thread | | | Date | Wed, 5 May 2021 10:37:29 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH RFC 0/9] PKS write protected page tables |
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On Tue, May 04, 2021 at 11:25:31PM -0700, Kees Cook wrote:
> It looks like PKS-protected page tables would be much like the > RO-protected text pages in the sense that there is already code in > the kernel to do things to make it writable, change text, and set it > read-only again (alternatives, ftrace, etc).
We don't actually modify text by changing the mapping at all. We modify through a writable (but not executable) temporary alias on the page (on x86).
Once a mapping is RX it will *never* be writable again (until we tear it all down).
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