From 3351918282fd664e918a3175ddfae9b15656122e Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Wed, 12 Jan 2011 09:55:30 +0100 Subject: [S390] Randomise the brk region Randomize heap address like other architectures do already. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/process.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'arch/s390/kernel/process.c') diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c index 38ff69e562c..26d48fe7299 100644 --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -341,3 +341,21 @@ unsigned long arch_align_stack(unsigned long sp) sp -= get_random_int() & ~PAGE_MASK; return sp & ~0xf; } + +static inline unsigned long brk_rnd(void) +{ + /* 8MB for 32bit, 1GB for 64bit */ + if (is_32bit_task()) + return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; + else + return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT; +} + +unsigned long arch_randomize_brk(struct mm_struct *mm) +{ + unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd()); + + if (ret < mm->brk) + return mm->brk; + return ret; +} -- cgit v1.2.3-70-g09d2