From 943741e352f8b0c524f542b93e8b62978dc0a9b0 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 15 Jul 2013 11:50:45 -0700 Subject: [PATCH] x86: make sure IDT is page aligned based on 4df05f361937ee86e5a8c9ead8aeb6a19ea9b7d7 upstream. Since the IDT is referenced from a fixmap, make sure it is page aligned. This avoids the risk of the IDT ever being moved in the bss and having the mapping be offset, resulting in calling incorrect handlers. In the current upstream kernel this is not a manifested bug, but heavily patched kernels (such as those using the PaX patch series) did encounter this bug. Signed-off-by: Kees Cook Reported-by: PaX Team Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Yinghai Lu Cc: Seiji Aguchi Cc: Fenghua Yu Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/head_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 321d65ebaffe..a8368608ab41 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -513,7 +513,7 @@ ENTRY(phys_base) #include "../../x86/xen/xen-head.S" .section .bss, "aw", @nobits - .align L1_CACHE_BYTES + .align PAGE_SIZE ENTRY(idt_table) .skip IDT_ENTRIES * 16 -- 2.20.1