sunsu: Fix use after free in su_remove().

Real serial port 'up' objects are statically allocated from an
array in the driver.  Keyboard and mouse ports, on the other
hand, are dynamically allocated.

Unfortunately, we free these dynamic 'up' objects before we unmap the
I/O registers.

Rearrange su_remove() so that this does not happen.

Noticed by Julia Lawall.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/serial/sunsu.c b/drivers/serial/sunsu.c
index 234459c2f012..ffbf4553f665 100644
--- a/drivers/serial/sunsu.c
+++ b/drivers/serial/sunsu.c
@@ -1500,20 +1500,25 @@ out_unmap:
 static int __devexit su_remove(struct of_device *op)
 {
         struct uart_sunsu_port *up = dev_get_drvdata(&op->dev);
+        bool kbdms = false;
 
         if (up->su_type == SU_PORT_MS ||
-            up->su_type == SU_PORT_KBD) {
+            up->su_type == SU_PORT_KBD)
+                kbdms = true;
+
+        if (kbdms) {
 #ifdef CONFIG_SERIO
                 serio_unregister_port(&up->serio);
 #endif
-                kfree(up);
-        } else if (up->port.type != PORT_UNKNOWN) {
+        } else if (up->port.type != PORT_UNKNOWN)
                 uart_remove_one_port(&sunsu_reg, &up->port);
-        }
 
         if (up->port.membase)
                 of_iounmap(&op->resource[0], up->port.membase, up->reg_size);
 
+        if (kbdms)
+                kfree(up);
+
         dev_set_drvdata(&op->dev, NULL);
 
         return 0;