linux-kernel - [PATCH 4.12 31/41] x86/elf: Remove the unnecessary ADDR_NO

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Message-Id: <20170822190943.178983577@linuxfoundation.org>
Date:   Tue, 22 Aug 2017 12:13:59 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Oleg Nesterov <oleg@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dmitry Safonov <dsafonov@...tuozzo.com>,
        Andy Lutomirski <luto@...capital.net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Borislav Petkov <bp@...e.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH 4.12 31/41] x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Oleg Nesterov <oleg@...hat.com>

commit 01578e36163cdd0e4fd61d9976de15f13364e26d upstream.

The ADDR_NO_RANDOMIZE checks in stack_maxrandom_size() and
randomize_stack_top() are not required.

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

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Dmitry Safonov <dsafonov@...tuozzo.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Borislav Petkov <bp@...e.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Link: http://lkml.kernel.org/r/20170815154011.GB1076@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/mm/mmap.c |    3 +--
 fs/binfmt_elf.c    |    3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

--- 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;
 	}
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -666,8 +666,7 @@ static unsigned long randomize_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;