1 files changed, 69 insertions, 14 deletions

diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index ce60a459a143..3cc15c066298 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -323,6 +323,25 @@ static inline void __poke_user_per(struct task_struct *child,
 		child->thread.per_user.end = data;
 }
 
+static void fixup_int_code(struct task_struct *child, addr_t data)
+{
+	struct pt_regs *regs = task_pt_regs(child);
+	int ilc = regs->int_code >> 16;
+	u16 insn;
+
+	if (ilc > 6)
+		return;
+
+	if (ptrace_access_vm(child, regs->psw.addr - (regs->int_code >> 16),
+			&insn, sizeof(insn), FOLL_FORCE) != sizeof(insn))
+		return;
+
+	/* double check that tracee stopped on svc instruction */
+	if ((insn >> 8) != 0xa)
+		return;
+
+	regs->int_code = 0x20000 | (data & 0xffff);
+}
 /*
  * Write a word to the user area of a process at location addr. This
  * operation does have an additional problem compared to peek_user.
@@ -334,7 +353,9 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 	struct user *dummy = NULL;
 	addr_t offset;
 
+
 	if (addr < (addr_t) &dummy->regs.acrs) {
+		struct pt_regs *regs = task_pt_regs(child);
 		/*
 		 * psw and gprs are stored on the stack
 		 */
@@ -352,7 +373,11 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 				/* Invalid addressing mode bits */
 				return -EINVAL;
 		}
-		*(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
+
+		if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
+			addr == offsetof(struct user, regs.gprs[2]))
+			fixup_int_code(child, data);
+		*(addr_t *)((addr_t) &regs->psw + addr) = data;
 
 	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
 		/*
@@ -718,6 +743,10 @@ static int __poke_user_compat(struct task_struct *child,
 			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
 				(__u64)(tmp & PSW32_ADDR_AMODE);
 		} else {
+
+			if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
+				addr == offsetof(struct compat_user, regs.gprs[2]))
+				fixup_int_code(child, data);
 			/* gpr 0-15 */
 			*(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
 		}
@@ -837,40 +866,66 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 {
 	unsigned long mask = -1UL;
+	long ret = -1;
+
+	if (is_compat_task())
+		mask = 0xffffffff;
 
 	/*
 	 * The sysc_tracesys code in entry.S stored the system
 	 * call number to gprs[2].
 	 */
 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
-	    (tracehook_report_syscall_entry(regs) ||
-	     regs->gprs[2] >= NR_syscalls)) {
+	    tracehook_report_syscall_entry(regs)) {
 		/*
-		 * Tracing decided this syscall should not happen or the
-		 * debugger stored an invalid system call number. Skip
+		 * Tracing decided this syscall should not happen. Skip
 		 * the system call and the system call restart handling.
 		 */
-		clear_pt_regs_flag(regs, PIF_SYSCALL);
-		return -1;
+		goto skip;
 	}
 
+#ifdef CONFIG_SECCOMP
 	/* Do the secure computing check after ptrace. */
-	if (secure_computing()) {
-		/* seccomp failures shouldn't expose any additional code. */
-		return -1;
+	if (unlikely(test_thread_flag(TIF_SECCOMP))) {
+		struct seccomp_data sd;
+
+		if (is_compat_task()) {
+			sd.instruction_pointer = regs->psw.addr & 0x7fffffff;
+			sd.arch = AUDIT_ARCH_S390;
+		} else {
+			sd.instruction_pointer = regs->psw.addr;
+			sd.arch = AUDIT_ARCH_S390X;
+		}
+
+		sd.nr = regs->int_code & 0xffff;
+		sd.args[0] = regs->orig_gpr2 & mask;
+		sd.args[1] = regs->gprs[3] & mask;
+		sd.args[2] = regs->gprs[4] & mask;
+		sd.args[3] = regs->gprs[5] & mask;
+		sd.args[4] = regs->gprs[6] & mask;
+		sd.args[5] = regs->gprs[7] & mask;
+
+		if (__secure_computing(&sd) == -1)
+			goto skip;
 	}
+#endif /* CONFIG_SECCOMP */
 
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
-		trace_sys_enter(regs, regs->gprs[2]);
+		trace_sys_enter(regs, regs->int_code & 0xffff);
 
-	if (is_compat_task())
-		mask = 0xffffffff;
 
-	audit_syscall_entry(regs->gprs[2], regs->orig_gpr2 & mask,
+	audit_syscall_entry(regs->int_code & 0xffff, regs->orig_gpr2 & mask,
 			    regs->gprs[3] &mask, regs->gprs[4] &mask,
 			    regs->gprs[5] &mask);
 
+	if ((signed long)regs->gprs[2] >= NR_syscalls) {
+		regs->gprs[2] = -ENOSYS;
+		ret = -ENOSYS;
+	}
 	return regs->gprs[2];
+skip:
+	clear_pt_regs_flag(regs, PIF_SYSCALL);
+	return ret;
 }
 
 asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)