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Commit c0d8e524 authored by Russell King's avatar Russell King Committed by Joonwoo Park
Browse files

ARM: make vectors page inaccessible from userspace 



If kuser helpers are not provided by the kernel, disable user access to
the vectors page.  With the kuser helpers gone, there is no reason for
this page to be visible to userspace.

Change-Id: Ia00a34e7952552634ccb03ee038cf3d0ead88459
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Git-commit: a5463cd3435475386cbbe7b06e01292ac169d36f
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[joonwoop@codeaurora.org: fixed merge conflict]
Signed-off-by: default avatarJoonwoo Park <joonwoop@codeaurora.org>
parent 06aaffd2

arch/arm/include/asm/page.h

+2 −0
Original line number Diff line number Diff line
@@ -142,7 +142,9 @@ extern void __cpu_copy_user_highpage(struct page *to, struct page *from, 
#define clear_page(page)	memset((void *)(page), 0, PAGE_SIZE)

extern void copy_page(void *to, const void *from);



#ifdef CONFIG_KUSER_HELPERS

#define __HAVE_ARCH_GATE_AREA 1

#endif



#ifdef CONFIG_ARM_LPAE

#include <asm/pgtable-3level-types.h>

arch/arm/kernel/process.c

+6 −1
Original line number Diff line number Diff line
@@ -566,6 +566,7 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) 
}



#ifdef CONFIG_MMU

#ifdef CONFIG_KUSER_HELPERS

/*

 * The vectors page is always readable from user space for the

 * atomic helpers. Insert it into the gate_vma so that it is visible
@@ -598,10 +599,14 @@ int in_gate_area_no_mm(unsigned long addr) 
{

	return in_gate_area(NULL, addr);

}

#define is_gate_vma(vma)	((vma) = &gate_vma)

#else

#define is_gate_vma(vma)	0

#endif



const char *arch_vma_name(struct vm_area_struct *vma)

{

	if (vma == &gate_vma)

	if (is_gate_vma(vma))

		return "[vectors]";

	else if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.sigpage)

		return "[sigpage]";

arch/arm/mm/mmu.c

+4 −0
Original line number Diff line number Diff line
@@ -1335,7 +1335,11 @@ static void __init devicemaps_init(struct machine_desc *mdesc) 
	map.pfn = __phys_to_pfn(virt_to_phys(vectors));

	map.virtual = 0xffff0000;

	map.length = PAGE_SIZE;

#ifdef CONFIG_KUSER_HELPERS

	map.type = MT_HIGH_VECTORS;

#else

	map.type = MT_LOW_VECTORS;

#endif

	create_mapping(&map);



	if (!vectors_high()) {