[PATCH 2/2] x86/elf: remove the unnecessary ADDR_NO_RANDOMIZE checks in stack_maxrandom_size() and randomize_stack_top()

Oleg Nesterov
2017-07-10T11:15:02Z

PF_RANDOMIZE is set by load_elf_binary() only if ADDR_NO_RANDOMIZE is not
set, no need to re-check after that.that.that.that.that.that.that.that.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
arch/x86/mm/mmap.c | 3 +--
fs/binfmt_elf.c | 3 +--
2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index 6369d04..81db3e9 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -50,8 +50,7 @@ unsigned long tasksize_64bit(void)
static unsigned long stack_maxrandom_size(unsigned long task_size)
{
unsigned long max = 0;
- if ((current->flags & PF_RANDOMIZE) &&
- !(current->personality & ADDR_NO_RANDOMIZE)) {
+ if (current->flags & PF_RANDOMIZE) {
max = (-1UL) & __STACK_RND_MASK(task_size == tasksize_32bit());
max <<= PAGE_SHIFT;
}
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 5075fd5..569c82e 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -666,8 +666,7 @@ static unsigned long randomize_stack_top(unsigned long stack_top)
{
unsigned long random_variable = 0;

- if ((current->flags & PF_RANDOMIZE) &&
- !(current->personality & ADDR_NO_RANDOMIZE)) {
+ if (current->flags & PF_RANDOMIZE) {
random_variable = get_random_long();
random_variable &= STACK_RND_MASK;
random_variable <<= PAGE_SHIFT;
--
2.5.0