tree f3b2902cc34603856ad5dbfcf2fc16ba7c7c77f1
parent 08456f54219660d0e84039e07af22a72304f19fe
author dcashman <dcashman@google.com> 1451432652 -0800
committer Kees Cook <keescook@google.com> 1458858726 -0700

FROMLIST: x86: mm: support ARCH_MMAP_RND_BITS.

(cherry picked from commit https://lkml.org/lkml/2015/12/21/339)

x86: arch_mmap_rnd() uses hard-coded values, 8 for 32-bit and 28 for
64-bit, to generate the random offset for the mmap base address.
This value represents a compromise between increased ASLR
effectiveness and avoiding address-space fragmentation. Replace it
with a Kconfig option, which is sensibly bounded, so that platform
developers may choose where to place this compromise. Keep default
values as new minimums.

Signed-off-by: Daniel Cashman <dcashman@android.com>
Signed-off-by: Daniel Cashman <dcashman@google.com>

Bug: 27796957
Patchset: ASLR sysctl

Change-Id: I0270b0e837c0fe7284d79c5dafe91e998c15a715
Signed-off-by: Kees Cook <keescook@google.com>