On Mon, Mar 02, 2015 at 04:19:44PM -0800, Kees Cook wrote:
> In preparation for exporting per-arch mmap randomization functions,
> this moves the ASLR calculations for mmap on ARM into a separate routine.
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Looks fine, thanks.
Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
> ---
> arch/arm/mm/mmap.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
> index 5e85ed371364..0f8bc158f2c6 100644
> --- a/arch/arm/mm/mmap.c
> +++ b/arch/arm/mm/mmap.c
> @@ -169,14 +169,21 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
> return addr;
> }
>
> -void arch_pick_mmap_layout(struct mm_struct *mm)
> +static unsigned long mmap_rnd(void)
> {
> - unsigned long random_factor = 0UL;
> + unsigned long rnd = 0UL;
>
> /* 8 bits of randomness in 20 address space bits */
> if ((current->flags & PF_RANDOMIZE) &&
> !(current->personality & ADDR_NO_RANDOMIZE))
> - random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT;
> + rnd = (get_random_int() % (1 << 8)) << PAGE_SHIFT;
> +
> + return rnd;
> +}
> +
> +void arch_pick_mmap_layout(struct mm_struct *mm)
> +{
> + unsigned long random_factor = mmap_rnd();
>
> if (mmap_is_legacy()) {
> mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
> --
> 1.9.1
>
--
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