Re: [PATCH v4 21/36] arm64/mm: Implement map_shadow_stack()
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2023-08-11 16:38:34
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On Mon, Aug 07, 2023 at 11:00:26PM +0100, Mark Brown wrote:
As discussed extensively in the changelog for the addition of this
syscall on x86 ("x86/shstk: Introduce map_shadow_stack syscall") the
existing mmap() and madvise() syscalls do not map entirely well onto the
security requirements for guarded control stacks since they lead to
windows where memory is allocated but not yet protected or stacks which
are not properly and safely initialised. Instead a new syscall
map_shadow_stack() has been defined which allocates and initialises a
shadow stack page.I guess I need to read the x86 discussion after all ;). Given that we won't have an mmap(PROT_SHADOW_STACK), are we going to have restrictions on mprotect()? E.g. it would be useful to reject a PROT_EXEC on the shadow stack. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel