From: Peter Zijlstra <pzijlstr@redhat.com>
Date: Thu, 10 Apr 2008 16:21:36 +0200
Subject: [x86_64] 32-bit address space randomization
Message-id: 1207837296.13860.4.camel@taijtu
O-Subject: Re: [PATCH RHEL5.2][BZ 222473] x86_64: address space randomization
Bugzilla: 213483

Hi,

Jakub spotted an imperfection in the address randomization of 32bit
processes on 64bit kernels, it would fail to randomize the brk.

It turns out that the ia32_binfmt.c ugliness disables asm-x86_64/elf.h
and thereby misses __HAVE_ARCH_RANDOMIZE_BRK.

Signed-off-by: Peter Zijlstra <pzijlstr@redhat.com>

Acked-by: Larry Woodman <lwoodman@redhat.com>

diff --git a/arch/x86_64/ia32/ia32_binfmt.c b/arch/x86_64/ia32/ia32_binfmt.c
index 3dbdf33..b7695d8 100644
--- a/arch/x86_64/ia32/ia32_binfmt.c
+++ b/arch/x86_64/ia32/ia32_binfmt.c
@@ -137,6 +137,10 @@ struct elf_prpsinfo
 #define user user32
 
 #define __ASM_X86_64_ELF_H 1
+
+#define __HAVE_ARCH_RANDOMIZE_BRK
+extern void randomize_brk(unsigned long old_brk);
+
 #define elf_read_implies_exec(ex, executable_stack)     (executable_stack != EXSTACK_DISABLE_X)
 //#include <asm/ia32.h>
 #include <linux/elf.h>