This is a note to let you know that I've just added the patch titled
ARM: make vectors page inaccessible from userspace
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-make-vectors-page-inaccessible-from-userspace.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a5463cd3435475386cbbe7b06e01292ac169d36f Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Date: Wed, 31 Jul 2013 21:58:56 +0100
Subject: ARM: make vectors page inaccessible from userspace
From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/page.h | 2 ++
arch/arm/kernel/process.c | 7 ++++++-
arch/arm/mm/mmu.c | 4 ++++
3 files changed, 12 insertions(+), 1 deletion(-)
--- a/arch/arm/include/asm/page.h
+++ b/arch/arm/include/asm/page.h
@@ -151,7 +151,9 @@ extern void __cpu_copy_user_highpage(str
#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>
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -528,6 +528,7 @@ unsigned long arch_randomize_brk(struct
}
#ifdef CONFIG_MMU
+#ifdef CONFIG_KUSER_HELPERS
/*
* The vectors page is always readable from user space for the
* atomic helpers and the signal restart code. Insert it into the
@@ -560,9 +561,13 @@ int in_gate_area_no_mm(unsigned long add
{
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]" : NULL;
+ return is_gate_vma(vma) ? "[vectors]" : NULL;
}
#endif
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1123,7 +1123,11 @@ static void __init devicemaps_init(struc
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()) {
Patches currently in stable-queue which might be from rmk+kernel@xxxxxxxxxxxxxxxx are
queue-3.4/arm-move-vector-stubs.patch
queue-3.4/arm-use-linker-magic-for-vectors-and-vector-stubs.patch
queue-3.4/arm-make-vectors-page-inaccessible-from-userspace.patch
queue-3.4/arm-allow-kuser-helpers-to-be-removed-from-the-vector-page.patch
queue-3.4/arm-poison-the-vectors-page.patch
queue-3.4/arm-update-fiq-support-for-relocation-of-vectors.patch
queue-3.4/arm-poison-memory-between-kuser-helpers.patch
--
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