Patch "x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks" has been added to the 4.12-stable tree

Patch "x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks" has been added to the 4.12-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-elf-remove-the-unnecessary-addr_no_randomize-checks.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 01578e36163cdd0e4fd61d9976de15f13364e26d Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 15 Aug 2017 17:40:11 +0200
Subject: x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks

From: Oleg Nesterov <oleg@redhat.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@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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;


Patches currently in stable-queue which might be from oleg@redhat.com are

queue-4.12/x86-elf-remove-the-unnecessary-addr_no_randomize-checks.patch
queue-4.12/mm-fix-double-mmap_sem-unlock-on-mmf_unstable-enforced-sigbus.patch
queue-4.12/x86-fix-norandmaps-addr_no_randomize.patch

Re: Patch "x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks" has been added to the 4.12-stable tree

[Oleg Nesterov]

On 08/20, gregkh@linuxfoundation.org wrote:
>
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.

Yes, I think this is not -stable material, this is really minor cleanup.

> From 01578e36163cdd0e4fd61d9976de15f13364e26d Mon Sep 17 00:00:00 2001
> From: Oleg Nesterov <oleg@redhat.com>
> Date: Tue, 15 Aug 2017 17:40:11 +0200
> Subject: x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks
> 
> From: Oleg Nesterov <oleg@redhat.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@redhat.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
> 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
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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;
> 
> 
> Patches currently in stable-queue which might be from oleg@redhat.com are
> 
> queue-4.12/x86-elf-remove-the-unnecessary-addr_no_randomize-checks.patch
> queue-4.12/mm-fix-double-mmap_sem-unlock-on-mmf_unstable-enforced-sigbus.patch
> queue-4.12/x86-fix-norandmaps-addr_no_randomize.patch

Re: Patch "x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks" has been added to the 4.12-stable tree

[Greg KH]

On Mon, Aug 21, 2017 at 04:21:34PM +0200, Oleg Nesterov wrote:
> On 08/20, gregkh@linuxfoundation.org wrote:
> >
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
> 
> Yes, I think this is not -stable material, this is really minor cleanup.

But I'm pretty sure it is needed for the patch after this one in the
series, right?

thanks,

greg k-h

Re: Patch "x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks" has been added to the 4.12-stable tree

[Oleg Nesterov]

On 08/22, Greg KH wrote:
>
> On Mon, Aug 21, 2017 at 04:21:34PM +0200, Oleg Nesterov wrote:
> > On 08/20, gregkh@linuxfoundation.org wrote:
> > >
> > > If you, or anyone else, feels it should not be added to the stable tree,
> > > please let <stable@vger.kernel.org> know about it.
> >
> > Yes, I think this is not -stable material, this is really minor cleanup.
>
> But I'm pretty sure it is needed for the patch after this one in the
> series, right?

Confused... it was 2/2, afaics nothing depends on this change. In particular, 1/2
47ac5484fd961420e5ec0bb5b972fde381f57365 ("x86: Fix norandmaps/ADDR_NO_RANDOMIZE")
doesn't depend.

Nevermind, if you have already applied this cleanup it should not hurt, it is
very simple and hopefully "obviously correct".

Oleg.