In preparation for splitting out ET_DYN ASLR, this moves the ASLR calculations for mmap on ARM into a separate routine, similar to x86. This also removes the redundant check of personality (PF_RANDOMIZE is already set before calling arch_pick_mmap_layout).
Signed-off-by: Kees Cook <[email protected]> --- arch/arm/mm/mmap.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 5e85ed371364..15a8160096b3 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -169,14 +169,22 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, return addr; } +static unsigned long mmap_rnd(void) +{ + unsigned long rnd; + + /* 8 bits of randomness in 20 address space bits */ + rnd = (unsigned long)get_random_int() % (1 << 8); + + return rnd << PAGE_SHIFT; +} + void arch_pick_mmap_layout(struct mm_struct *mm) { unsigned long random_factor = 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; + if (current->flags & PF_RANDOMIZE) + random_factor = mmap_rnd(); if (mmap_is_legacy()) { mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
