[PATCH] i386/x86-64: Don't randomize stack top when no randomization personality is set

Based on patch from Frank van Maarseveen <frankvm@frankvm.com>, but
extended.

Signed-off-by: Andi Kleen <ak@suse.de>

3 files changed, 5 insertions, 3 deletions

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 8657c739656a..b741c3e1a5eb 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -37,6 +37,7 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/random.h>
+#include <linux/personality.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -905,7 +906,7 @@ asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
 
 unsigned long arch_align_stack(unsigned long sp)
 {
-        if (randomize_va_space)
+        if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
                 sp -= get_random_int() % 8192;
         return sp & ~0xf;
 }
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 6e0527635b4c..6fbd19564e4e 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -845,7 +845,7 @@ int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 
 unsigned long arch_align_stack(unsigned long sp)
 {
-        if (randomize_va_space)
+        if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
                 sp -= get_random_int() % 8192;
         return sp & ~0xf;
 }
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 672a3b90bc55..5109dbff93bf 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -515,7 +515,8 @@ static unsigned long randomize_stack_top(unsigned long stack_top)
 {
         unsigned int random_variable = 0;
 
-        if (current->flags & PF_RANDOMIZE) {
+        if ((current->flags & PF_RANDOMIZE) &&
+                !(current->personality & ADDR_NO_RANDOMIZE)) {
                 random_variable = get_random_int() & STACK_RND_MASK;
                 random_variable <<= PAGE_SHIFT;
         }