From: Marcus Meissner <meissner@suse.de>

Randomizes -pie compiled binaries from PAGE_SIZE up to ELF_ET_DYN_BASE.

0 -> PAGE_SIZE is excluded to allow NULL ptr accesses to fail.

Signed-off-by: Marcus Meissner <meissner@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 fs/binfmt_elf.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletion(-)

diff -puN fs/binfmt_elf.c~binfmt_elf-randomize-pie-binaries fs/binfmt_elf.c
--- a/fs/binfmt_elf.c~binfmt_elf-randomize-pie-binaries
+++ a/fs/binfmt_elf.c
@@ -856,7 +856,13 @@ static int load_elf_binary(struct linux_
 			 * default mmap base, as well as whatever program they
 			 * might try to exec.  This is because the brk will
 			 * follow the loader, and is not movable.  */
-			load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
+			if (current->flags & PF_RANDOMIZE)
+				load_bias = randomize_range(PAGE_SIZE,
+							    ELF_ET_DYN_BASE,
+							    0);
+			else
+				load_bias = ELF_ET_DYN_BASE;
+			load_bias = ELF_PAGESTART(load_bias - vaddr);
 		}
 
 		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
_