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Commit 8d66db50 authored by Elena Reshetova's avatar Elena Reshetova Committed by Greg Kroah-Hartman
Browse files

drivers, usb: convert ep_data.count from atomic_t to refcount_t 



refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b7ddc981

drivers/usb/gadget/legacy/inode.c

+4 −4
Original line number Original line Diff line number Diff line
@@ -191,7 +191,7 @@ enum ep_state { 
struct ep_data {

struct ep_data {

	struct mutex			lock;

	struct mutex			lock;

	enum ep_state			state;

	enum ep_state			state;

	atomic_t			count;

	refcount_t			count;

	struct dev_data			*dev;

	struct dev_data			*dev;

	/* must hold dev->lock before accessing ep or req */

	/* must hold dev->lock before accessing ep or req */

	struct usb_ep			*ep;

	struct usb_ep			*ep;
@@ -206,12 +206,12 @@ struct ep_data { 




static inline void get_ep (struct ep_data *data)

static inline void get_ep (struct ep_data *data)

{

{

	atomic_inc (&data->count);

	refcount_inc (&data->count);

}

}





static void put_ep (struct ep_data *data)

static void put_ep (struct ep_data *data)

{

{

	if (likely (!atomic_dec_and_test (&data->count)))

	if (likely (!refcount_dec_and_test (&data->count)))

		return;

		return;

	put_dev (data->dev);

	put_dev (data->dev);

	/* needs no more cleanup */

	/* needs no more cleanup */
@@ -1562,7 +1562,7 @@ static int activate_ep_files (struct dev_data *dev) 
		init_waitqueue_head (&data->wait);

		init_waitqueue_head (&data->wait);





		strncpy (data->name, ep->name, sizeof (data->name) - 1);

		strncpy (data->name, ep->name, sizeof (data->name) - 1);

		atomic_set (&data->count, 1);

		refcount_set (&data->count, 1);

		data->dev = dev;

		data->dev = dev;

		get_dev (dev);

		get_dev (dev);