1 files changed, 12 insertions, 2 deletions

diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index a1e8a8694bb7..593fcc9253fc 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -309,6 +309,10 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
         regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
                 (__u64)(regs32.psw.mask & PSW32_MASK_USER) << 32 |
                 (__u64)(regs32.psw.addr & PSW32_ADDR_AMODE);
+        /* Check for invalid user address space control. */
+        if ((regs->psw.mask & PSW_MASK_ASC) >= (psw_kernel_bits & PSW_MASK_ASC))
+                regs->psw.mask = (psw_user_bits & PSW_MASK_ASC) |
+                        (regs->psw.mask & ~PSW_MASK_ASC);
         regs->psw.addr = (__u64)(regs32.psw.addr & PSW32_ADDR_INSN);
         for (i = 0; i < NUM_GPRS; i++)
                 regs->gprs[i] = (__u64) regs32.gprs[i];
@@ -481,7 +485,10 @@ static int setup_frame32(int sig, struct k_sigaction *ka,
 
         /* Set up registers for signal handler */
         regs->gprs[15] = (__force __u64) frame;
-        regs->psw.mask |= PSW_MASK_BA;          /* force amode 31 */
+        /* Force 31 bit amode and default user address space control. */
+        regs->psw.mask = PSW_MASK_BA |
+                (psw_user_bits & PSW_MASK_ASC) |
+                (regs->psw.mask & ~PSW_MASK_ASC);
         regs->psw.addr = (__force __u64) ka->sa.sa_handler;
 
         regs->gprs[2] = map_signal(sig);
@@ -549,7 +556,10 @@ static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
 
         /* Set up registers for signal handler */
         regs->gprs[15] = (__force __u64) frame;
-        regs->psw.mask |= PSW_MASK_BA;          /* force amode 31 */
+        /* Force 31 bit amode and default user address space control. */
+        regs->psw.mask = PSW_MASK_BA |
+                (psw_user_bits & PSW_MASK_ASC) |
+                (regs->psw.mask & ~PSW_MASK_ASC);
         regs->psw.addr = (__u64) ka->sa.sa_handler;
 
         regs->gprs[2] = map_signal(sig);