[PATCH] Randomisation: add ADDR_NO_RANDOMIZE personality

Introduce a personality that disables randomisation, so that users can use
setarch and related commands to run specific applications without
randomisation.
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/binfmt_elf.c

@@ -753,7 +753,7 @@ static int load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
 		current->personality |= READ_IMPLIES_EXEC;
 
-	if (executable_stack == EXSTACK_DISABLE_X && randomize_va_space)
+	if ( !(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 		current->flags |= PF_RANDOMIZE;
 	arch_pick_mmap_layout(current->mm);
 

include/linux/personality.h

@@ -18,6 +18,7 @@ extern int		__set_personality(unsigned long);
  * These occupy the top three bytes.
  */
 enum {
+	ADDR_NO_RANDOMIZE = 	0x0040000,	/* disable randomization of VA space */
 	FDPIC_FUNCPTRS =	0x0080000,	/* userspace function ptrs point to descriptors
 						 * (signal handling)
 						 */
@@ -35,7 +36,7 @@ enum {
  * Security-relevant compatibility flags that must be
  * cleared upon setuid or setgid exec:
  */
-#define PER_CLEAR_ON_SETID (READ_IMPLIES_EXEC)
+#define PER_CLEAR_ON_SETID (READ_IMPLIES_EXEC|ADDR_NO_RANDOMIZE)
 
 /*
  * Personality types.