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Groups > linux.kernel > #1713224

[tip:x86/urgent] x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks

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Commit-ID:  01578e36163cdd0e4fd61d9976de15f13364e26d
Gitweb:     http://git.kernel.org/tip/01578e36163cdd0e4fd61d9976de15f13364e26d
Author:     Oleg Nesterov <oleg@redhat.com>
AuthorDate: Tue, 15 Aug 2017 17:40:11 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 16 Aug 2017 20:32:02 +0200

x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks

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@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: stable@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20170815154011.GB1076@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 c94df12..a88cfbf 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 879ff9c..6466153 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -664,8 +664,7 @@ 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;

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[PATCH v2 0/2] x86: fix norandmaps/ADDR_NO_RANDOMIZE Oleg Nesterov <oleg@redhat.com> - 2017-08-15 17:40 +0200
  [PATCH v2 1/2] x86: fix norandmaps/ADDR_NO_RANDOMIZE Oleg Nesterov <oleg@redhat.com> - 2017-08-15 17:50 +0200
    [tip:x86/urgent] x86: Fix norandmaps/ADDR_NO_RANDOMIZE tip-bot for Oleg Nesterov <tipbot@zytor.com> - 2017-08-16 20:50 +0200
  [PATCH v2 2/2] x86/elf: remove the unnecessary ADDR_NO_RANDOMIZE  checks in stack_maxrandom_size() and randomize_stack_top() Oleg Nesterov <oleg@redhat.com> - 2017-08-15 17:50 +0200
    [tip:x86/urgent] x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE  checks tip-bot for Oleg Nesterov <tipbot@zytor.com> - 2017-08-16 20:40 +0200

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