diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-07-31 21:58:56 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-11 18:35:20 -0700 |
| commit | 75bc4446e0d553aceeb632ae05878786d6760e47 (patch) | |
| tree | b4ddcbc70fcadad7ccca9bca9f994b1619e9b0c0 /arch/arm | |
| parent | a5510daad56d3b9738d475957750db9d4fc607a9 (diff) | |
ARM: make vectors page inaccessible from userspace
commit a5463cd3435475386cbbe7b06e01292ac169d36f upstream.
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.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/page.h | 2 | ||||
| -rw-r--r-- | arch/arm/kernel/process.c | 7 | ||||
| -rw-r--r-- | arch/arm/mm/mmu.c | 4 |
3 files changed, 12 insertions, 1 deletions
diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h index 812a4944e78..cbdc7a21f86 100644 --- a/arch/arm/include/asm/page.h +++ b/arch/arm/include/asm/page.h @@ -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> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 72315e7be22..1ed29cc2297 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -433,6 +433,7 @@ 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 @@ -465,10 +466,14 @@ 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) { - return (vma == &gate_vma) ? "[vectors]" : + return is_gate_vma(vma) ? "[vectors]" : (vma->vm_mm && vma->vm_start == vma->vm_mm->context.sigpage) ? "[sigpage]" : NULL; } diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 08b37c421a5..daf336fe0be 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1220,7 +1220,11 @@ 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()) { |