Implement mmap base randomization for the bottom up direction, so ASLR works for both mmap layouts on s390. See also df54d6fa54 "x86 get_unmapped_area(): use proper mmap base for bottom-up direction".
Signed-off-by: Heiko Carstens <[email protected]> --- arch/s390/mm/mmap.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 4002329..7110c0f 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -64,6 +64,11 @@ static unsigned long mmap_rnd(void) return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; } +static unsigned long mmap_base_legacy(void) +{ + return TASK_UNMAPPED_BASE + mmap_rnd(); +} + static inline unsigned long mmap_base(void) { unsigned long gap = rlimit(RLIMIT_STACK); @@ -89,7 +94,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm) * bit is set, or if the expected stack growth is unlimited: */ if (mmap_is_legacy()) { - mm->mmap_base = TASK_UNMAPPED_BASE; + mm->mmap_base = mmap_base_legacy(); mm->get_unmapped_area = arch_get_unmapped_area; } else { mm->mmap_base = mmap_base(); @@ -172,7 +177,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm) * bit is set, or if the expected stack growth is unlimited: */ if (mmap_is_legacy()) { - mm->mmap_base = TASK_UNMAPPED_BASE; + mm->mmap_base = mmap_base_legacy(); mm->get_unmapped_area = s390_get_unmapped_area; } else { mm->mmap_base = mmap_base(); -- 1.8.3.4 -- 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/
