Commit b34d2ef0 authored Nov 07, 2018 by Ard Biesheuvel Committed by Will Deacon Nov 20, 2018

arm64: mm: purge lazily unmapped vm regions before changing permissions

Call vm_unmap_aliases() every time we apply any changes to permission
attributes of mappings in the vmalloc region. This avoids any potential
issues resulting from lingering writable or executable aliases of
mappings that should be read-only or non-executable, respectively.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

parent 9ff01193

arch/arm64/mm/pageattr.c

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -93,6 +93,12 @@ static int change_memory_common(unsigned long addr, int numpages,
	if (!numpages)		if (!numpages)
	return 0;		return 0;

			/*
			* Get rid of potentially aliasing lazily unmapped vm areas that may
			* have permissions set that deviate from the ones we are setting here.
			*/
			vm_unmap_aliases();

	return __change_memory_common(start, size, set_mask, clear_mask);		return __change_memory_common(start, size, set_mask, clear_mask);
	}		}

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