2009-10-25 13:16:48

by André Goddard Rosa

Subject: [PATCH 1/2] serial: fix NULL pointer dereference

>From f90016f1d9186ba44da028201a984735fc9a6672 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Goddard=20Rosa?= <[email protected]>
Date: Sat, 24 Oct 2009 11:04:25 -0200
Subject: [PATCH 1/2] serial: fix NULL pointer dereference
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

If kzalloc() or alloc_tty_driver() fails, we call:
put_tty_driver(normal = NULL).

Then:
put_tty_driver -> tty_driver_kref_put -> kref_put(&NULL->kref, ...)

Signed-off-by: Andr? Goddard Rosa <[email protected]>

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index dcc7244..885eabe 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -2344,7 +2344,7 @@ static const struct tty_operations uart_ops = {
*/
int uart_register_driver(struct uart_driver *drv)
{
- struct tty_driver *normal = NULL;
+ struct tty_driver *normal;
int i, retval;

BUG_ON(drv->state);
@@ -2354,13 +2354,12 @@ int uart_register_driver(struct uart_driver *drv)
* we have a large number of ports to handle.
*/
drv->state = kzalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);
- retval = -ENOMEM;
if (!drv->state)
goto out;

- normal = alloc_tty_driver(drv->nr);
+ normal = alloc_tty_driver(drv->nr);
if (!normal)
- goto out;
+ goto out_kfree;

drv->tty_driver = normal;

@@ -2393,12 +2392,14 @@ int uart_register_driver(struct uart_driver *drv)
}

retval = tty_register_driver(normal);
- out:
- if (retval < 0) {
- put_tty_driver(normal);
- kfree(drv->state);
- }
- return retval;
+ if (retval >= 0)
+ return retval;
+
+ put_tty_driver(normal);
+out_kfree:
+ kfree(drv->state);
+out:
+ return -ENOMEM;
}

/**
--
1.6.5.1.75.g02d56