Re: [GIT PULL] one vdso fix for x86/urgent

[Ingo Molnar <mingo@kernel.org>]

* Andy Lutomirski <luto@amacapital.net> wrote:

> Hi Ingo, etc,
> 
> Please consider pulling for x86/urgent.  This fixes a longstanding,
> albeit relatively minor, issue in the x86 vdso randomization
> algorithm.  Note that this isn't super-urgent, as this bug isn't
> directly exploitable, and it's as old as the vdso itself.
> 
> Thanks,
> Andy
> 
> The following changes since commit e589c9e13aeb0c5539bf1314b3a78442ea8fc0c2:
> 
>   Merge branch 'x86-apic-for-linus' of
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (2014-12-19
> 14:02:02 -0800)
> 
> are available in the git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git
> tags/pr-20141220-x86-vdso
> 
> for you to fetch changes up to 394f56fe480140877304d342dec46d50dc823d46:
> 
>   x86_64, vdso: Fix the vdso address randomization algorithm
> (2014-12-20 16:56:57 -0800)
> 
> ----------------------------------------------------------------
> One vdso fix for a longstanding ASLR bug that's been in the news lately.
> 
> The vdso base address has always been randomized, and I don't think there's
> anything particularly wrong with the range over which it's randomized,
> but the implementation seems to have been buggy since the very beginning.
> 
> This fixes the implementation to remove a large bias that caused a small
> fraction of possible vdso load addresess to be vastly more likely than
> the rest of the possible addresses.
> 
> ----------------------------------------------------------------
> Andy Lutomirski (1):
>       x86_64, vdso: Fix the vdso address randomization algorithm
> 
>  arch/x86/vdso/vma.c | 45 +++++++++++++++++++++++++++++----------------
>  1 file changed, 29 insertions(+), 16 deletions(-)

Pulled into tip:x86/urgent, thanks a lot Andy!

	Ingo