[patch] Bluetooth: 6lowpan: use after free in disconnect_devices()

[patch] Bluetooth: 6lowpan: use after free in disconnect_devices()

[Dan Carpenter]

This was accidentally changed from list_for_each_entry_safe() to
list_for_each_entry() so now it has a use after free bug.  I've changed
it back.

Fixes: 90305829635d ('Bluetooth: 6lowpan: Converting rwlocks to use RCU')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 7254bdd..eef298d 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -1383,7 +1383,7 @@ static const struct file_operations lowpan_control_fops = {
 
 static void disconnect_devices(void)
 {
-	struct lowpan_dev *entry, *new_dev;
+	struct lowpan_dev *entry, *tmp, *new_dev;
 	struct list_head devices;
 
 	INIT_LIST_HEAD(&devices);
@@ -1408,7 +1408,7 @@ static void disconnect_devices(void)
 
 	rcu_read_unlock();
 
-	list_for_each_entry(entry, &devices, list) {
+	list_for_each_entry_safe(entry, tmp, &devices, list) {
 		ifdown(entry->netdev);
 		BT_DBG("Unregistering netdev %s %p",
 		       entry->netdev->name, entry->netdev);

Re: [patch] Bluetooth: 6lowpan: use after free in disconnect_devices()

[Jukka Rissanen]

Hi Dan,

On ke, 2014-10-29 at 19:10 +0300, Dan Carpenter wrote:
> This was accidentally changed from list_for_each_entry_safe() to
> list_for_each_entry() so now it has a use after free bug.  I've changed
> it back.

Good catch! Thanks for the patch.

Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>

> 
> Fixes: 90305829635d ('Bluetooth: 6lowpan: Converting rwlocks to use RCU')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
> index 7254bdd..eef298d 100644
> --- a/net/bluetooth/6lowpan.c
> +++ b/net/bluetooth/6lowpan.c
> @@ -1383,7 +1383,7 @@ static const struct file_operations lowpan_control_fops = {
>  
>  static void disconnect_devices(void)
>  {
> -	struct lowpan_dev *entry, *new_dev;
> +	struct lowpan_dev *entry, *tmp, *new_dev;
>  	struct list_head devices;
>  
>  	INIT_LIST_HEAD(&devices);
> @@ -1408,7 +1408,7 @@ static void disconnect_devices(void)
>  
>  	rcu_read_unlock();
>  
> -	list_for_each_entry(entry, &devices, list) {
> +	list_for_each_entry_safe(entry, tmp, &devices, list) {
>  		ifdown(entry->netdev);
>  		BT_DBG("Unregistering netdev %s %p",
>  		       entry->netdev->name, entry->netdev);
> --
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Cheers,
Jukka

Re: [patch] Bluetooth: 6lowpan: use after free in disconnect_devices()

[Marcel Holtmann]

Hi Dan,

> This was accidentally changed from list_for_each_entry_safe() to
> list_for_each_entry() so now it has a use after free bug.  I've changed
> it back.
> 
> Fixes: 90305829635d ('Bluetooth: 6lowpan: Converting rwlocks to use RCU')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

patch has been applied to bluetooth-next tree.

Regards

Marcel