[PATCH] Make copy_siginfo_to_user mode explicit

This patch makes copy_siginfo_to_user excplicitly copy the correct
union member.  Previously we were getting the correct result but
really by accident.

kernel/signal.c

@@ -1043,37 +1043,58 @@ sys_rt_sigpending(sigset_t *set, size_t sigsetsize)
 
 int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
 {
+	int err;
+
 	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
 		return -EFAULT;
 	if (from->si_code < 0)
-		return __copy_to_user(to, from, sizeof(siginfo_t));
-	else {
-		int err;
-
-		/* If you change siginfo_t structure, please be sure
-		   this code is fixed accordingly.
-		   It should never copy any pad contained in the structure
-		   to avoid security leaks, but must copy the generic
-		   3 ints plus the relevant union member.  */
+		return __copy_to_user(to, from, sizeof(siginfo_t))
+			? -EFAULT : 0;
+	/*
+	 * If you change siginfo_t structure, please be sure
+	 * this code is fixed accordingly.
+	 * It should never copy any pad contained in the structure
+	 * to avoid security leaks, but must copy the generic
+	 * 3 ints plus the relevant union member.
+	 */
 	err = __put_user(from->si_signo, &to->si_signo);
 	err |= __put_user(from->si_errno, &to->si_errno);
 	err |= __put_user((short)from->si_code, &to->si_code);
-		/* First 32bits of unions are always present.  */
+	switch (from->si_code & __SI_MASK) {
+	case __SI_KILL:
 		err |= __put_user(from->si_pid, &to->si_pid);
-		switch (from->si_code >> 16) {
-		case __SI_FAULT >> 16:
+		err |= __put_user(from->si_uid, &to->si_uid);
+		break;
+	case __SI_TIMER:
+		err |= __put_user(from->si_timer1, &to->si_timer1);
+		err |= __put_user(from->si_timer2, &to->si_timer2);
+		break;
+	case __SI_POLL:
+		err |= __put_user(from->si_band, &to->si_band);
+		err |= __put_user(from->si_fd, &to->si_fd);
+		break;
+	case __SI_FAULT:
+		err |= __put_user(from->si_addr, &to->si_addr);
 		break;
-		case __SI_CHLD >> 16:
+	case __SI_CHLD:
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		err |= __put_user(from->si_status, &to->si_status);
 		err |= __put_user(from->si_utime, &to->si_utime);
 		err |= __put_user(from->si_stime, &to->si_stime);
-			err |= __put_user(from->si_status, &to->si_status);
-		default:
+		break;
+	case __SI_RT: /* This is not generated by the kernel as of now. */
+		err |= __put_user(from->si_pid, &to->si_pid);
+		err |= __put_user(from->si_uid, &to->si_uid);
+		err |= __put_user(from->si_int, &to->si_int);
+		err |= __put_user(from->si_ptr, &to->si_ptr);
+		break;
+	default: /* this is just in case for now ... */
+		err |= __put_user(from->si_pid, &to->si_pid);
 		err |= __put_user(from->si_uid, &to->si_uid);
 		break;
-		/* case __SI_RT: This is not generated by the kernel as of now.  */
 	}
 	return err;
-	}
 }
 
 #endif