From 2578cf95969936c372db29ee2bbc21c9b6a299aa Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 7 Oct 2009 17:38:24 -0400 Subject: x86: Increase MIN_GAP to include randomized stack [ trivial backport to 2.6.27: Chuck Ebbert ] commit 80938332d8cf652f6b16e0788cf0ca136befe0b5 upstream. Currently we are not including randomized stack size when calculating mmap_base address in arch_pick_mmap_layout for topdown case. This might cause that mmap_base starts in the stack reserved area because stack is randomized by 1GB for 64b (8MB for 32b) and the minimum gap is 128MB. If the stack really grows down to mmap_base then we can get silent mmap region overwrite by the stack values. Let's include maximum stack randomization size into MIN_GAP which is used as the low bound for the gap in mmap. Signed-off-by: Michal Hocko LKML-Reference: <1252400515-6866-1-git-send-email-mhocko@suse.cz> Acked-by: Jiri Kosina Signed-off-by: H. Peter Anvin Cc: Chuck Ebbert Signed-off-by: Greg Kroah-Hartman --- include/asm-x86/elf.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/asm-x86/elf.h b/include/asm-x86/elf.h index 7be4733c793e..36343b6935d5 100644 --- a/include/asm-x86/elf.h +++ b/include/asm-x86/elf.h @@ -287,6 +287,8 @@ do { \ #ifdef CONFIG_X86_32 +#define STACK_RND_MASK (0x7ff) + #define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO)) #define ARCH_DLINFO ARCH_DLINFO_IA32(vdso_enabled) -- cgit v1.2.3