Input: serport - add compat handling for SPIOCSTYPE ioctl

When running a 32-bit inputattach utility in a 64-bit system, there will be
error code "inputattach: can't set device type". This is caused by the
serport device driver not supporting compat_ioctl, so that SPIOCSTYPE ioctl
fails.

Cc: stable@vger.kernel.org
Signed-off-by: John Sung <penmount.touch@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/serio/serport.c b/drivers/input/serio/serport.c
index 0cb7ef59071b792a350a914e88f4e9be7da34efc..69175b8253468cf5d2319659b1496e3ac32d5b10 100644 (file)
--- a/drivers/input/serio/serport.c
+++ b/drivers/input/serio/serport.c
@@ -21,6 +21,7 @@
 #include <linux/init.h>
 #include <linux/serio.h>
 #include <linux/tty.h>
+#include <linux/compat.h>
 
 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 MODULE_DESCRIPTION("Input device TTY line discipline");
@@ -198,28 +199,55 @@ static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, u
        return 0;
 }
 
+static void serport_set_type(struct tty_struct *tty, unsigned long type)
+{
+       struct serport *serport = tty->disc_data;
+
+       serport->id.proto = type & 0x000000ff;
+       serport->id.id    = (type & 0x0000ff00) >> 8;
+       serport->id.extra = (type & 0x00ff0000) >> 16;
+}
+
 /*
  * serport_ldisc_ioctl() allows to set the port protocol, and device ID
  */
 
-static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg)
+static int serport_ldisc_ioctl(struct tty_struct *tty, struct file *file,
+                              unsigned int cmd, unsigned long arg)
 {
-       struct serport *serport = (struct serport*) tty->disc_data;
-       unsigned long type;
-
        if (cmd == SPIOCSTYPE) {
+               unsigned long type;
+
                if (get_user(type, (unsigned long __user *) arg))
                        return -EFAULT;
 
-               serport->id.proto = type & 0x000000ff;
-               serport->id.id    = (type & 0x0000ff00) >> 8;
-               serport->id.extra = (type & 0x00ff0000) >> 16;
+               serport_set_type(tty, type);
+               return 0;
+       }
+
+       return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+#define COMPAT_SPIOCSTYPE      _IOW('q', 0x01, compat_ulong_t)
+static long serport_ldisc_compat_ioctl(struct tty_struct *tty,
+                                      struct file *file,
+                                      unsigned int cmd, unsigned long arg)
+{
+       if (cmd == COMPAT_SPIOCSTYPE) {
+               void __user *uarg = compat_ptr(arg);
+               compat_ulong_t compat_type;
+
+               if (get_user(compat_type, (compat_ulong_t __user *)uarg))
+                       return -EFAULT;
 
+               serport_set_type(tty, compat_type);
                return 0;
        }
 
        return -EINVAL;
 }
+#endif
 
 static void serport_ldisc_write_wakeup(struct tty_struct * tty)
 {
@@ -243,6 +271,9 @@ static struct tty_ldisc_ops serport_ldisc = {
        .close =        serport_ldisc_close,
        .read =         serport_ldisc_read,
        .ioctl =        serport_ldisc_ioctl,
+#ifdef CONFIG_COMPAT
+       .compat_ioctl = serport_ldisc_compat_ioctl,
+#endif
        .receive_buf =  serport_ldisc_receive,
        .write_wakeup = serport_ldisc_write_wakeup
 };