brk randomization: introduce CONFIG_COMPAT_BRK

based on similar patch from: Pavel Machek <pavel@ucw.cz>

Introduce CONFIG_COMPAT_BRK. If disabled then the kernel is free
(but not obliged to) randomize the brk area.

Heap randomization breaks ancient binaries, so we keep COMPAT_BRK
enabled by default.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 4628c42ca892..111771d38e6e 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1077,7 +1077,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
         current->mm->start_stack = bprm->p;
 
 #ifdef arch_randomize_brk
-        if (current->flags & PF_RANDOMIZE)
+        if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1))
                 current->mm->brk = current->mm->start_brk =
                         arch_randomize_brk(current->mm);
 #endif