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: Russell 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]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index de9a39c..dd8c63d 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -673,6 +673,7 @@
}
#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
@@ -705,10 +706,14 @@
{
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]";