The IBT bitmap is visiable from user-mode, but not writable.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
---
arch/x86/mm/fault.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 59f4f66e4f2e..231196abb62e 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1454,6 +1454,13 @@ void do_user_addr_fault(struct pt_regs *regs,
* we can handle it..
*/
good_area:
+#define USER_MODE_WRITE (FAULT_FLAG_WRITE | FAULT_FLAG_USER)
+ if (((flags & USER_MODE_WRITE) == USER_MODE_WRITE) &&
+ (vma->vm_flags & VM_IBT)) {
+ bad_area_access_error(regs, hw_error_code, address, vma);
+ return;
+ }
+
if (unlikely(access_error(hw_error_code, vma))) {
bad_area_access_error(regs, hw_error_code, address, vma);
return;
--
2.17.1
