| Date | Mon, 18 Dec 2017 15:21:13 +0100 | From | Borislav Petkov <> | Subject | Re: [patch V163 02/51] x86/vsyscall/64: Explicitly set _PAGE_USER in the pagetable hierarchy |
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On Mon, Dec 18, 2017 at 12:42:17PM +0100, Thomas Gleixner wrote: > From: Andy Lutomirski <luto@kernel.org> > > The kernel is very erratic as to which pagetables have _PAGE_USER set. The > vsyscall page gets lucky: it seems that all of the relevant pagetables are > among the apparently arbitrary ones that set _PAGE_USER. Rather than > relying on chance, just explicitly set _PAGE_USER. > > This will let us clean up pagetable setup to stop setting _PAGE_USER. The > added code can also be reused by pagetable isolation to manage the > _PAGE_USER bit in the usermode tables. > > Signed-off-by: Andy Lutomirski <luto@kernel.org> > Signed-off-by: Ingo Molnar <mingo@kernel.org> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: Borislav Petkov <bp@alien8.de> > Cc: Brian Gerst <brgerst@gmail.com> > Cc: David Laight <David.Laight@aculab.com> > Cc: Kees Cook <keescook@chromium.org> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > --- > arch/x86/entry/vsyscall/vsyscall_64.c | 33 ++++++++++++++++++++++++++++++++- > 1 file changed, 32 insertions(+), 1 deletion(-)
Nice.
Reviewed-by: Borislav Petkov <bp@suse.de>
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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