From bae1cd368c45d1127e054e90305d585dbc8b3b46 Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Thu, 29 Apr 2021 11:14:51 +0200 Subject: s390/entry: add support for syscall stack randomization This adds support for adding a random offset to the stack while handling syscalls. The patch uses get_tod_clock_fast() as this is considered good enough and has much less performance penalty compared to using get_random_int(). The patch also adds randomization in pgm_check_handler() as the sigreturn/rt_sigreturn system calls might be called from there. Signed-off-by: Sven Schnelle Link: https://lore.kernel.org/r/20210429091451.1062594-1-svens@linux.ibm.com Signed-off-by: Heiko Carstens --- arch/s390/kernel/syscall.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/s390/kernel/syscall.c') diff --git a/arch/s390/kernel/syscall.c b/arch/s390/kernel/syscall.c index bc8e650e377d..4e5cc7d2364e 100644 --- a/arch/s390/kernel/syscall.c +++ b/arch/s390/kernel/syscall.c @@ -142,6 +142,7 @@ void do_syscall(struct pt_regs *regs) void noinstr __do_syscall(struct pt_regs *regs, int per_trap) { + add_random_kstack_offset(); enter_from_user_mode(regs); memcpy(®s->gprs[8], S390_lowcore.save_area_sync, 8 * sizeof(unsigned long)); -- cgit v1.2.3