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>
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 4628c42..111771d 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1077,7 +1077,7 @@
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