Commit b7ddc981 authored by Elena Reshetova's avatar Elena Reshetova Committed by Greg Kroah-Hartman

drivers, usb: convert dev_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 43938613
...@@ -27,6 +27,7 @@ ...@@ -27,6 +27,7 @@
#include <linux/mmu_context.h> #include <linux/mmu_context.h>
#include <linux/aio.h> #include <linux/aio.h>
#include <linux/uio.h> #include <linux/uio.h>
#include <linux/refcount.h>
#include <linux/device.h> #include <linux/device.h>
#include <linux/moduleparam.h> #include <linux/moduleparam.h>
...@@ -114,7 +115,7 @@ enum ep0_state { ...@@ -114,7 +115,7 @@ enum ep0_state {
struct dev_data { struct dev_data {
spinlock_t lock; spinlock_t lock;
atomic_t count; refcount_t count;
enum ep0_state state; /* P: lock */ enum ep0_state state; /* P: lock */
struct usb_gadgetfs_event event [N_EVENT]; struct usb_gadgetfs_event event [N_EVENT];
unsigned ev_next; unsigned ev_next;
...@@ -150,12 +151,12 @@ struct dev_data { ...@@ -150,12 +151,12 @@ struct dev_data {
static inline void get_dev (struct dev_data *data) static inline void get_dev (struct dev_data *data)
{ {
atomic_inc (&data->count); refcount_inc (&data->count);
} }
static void put_dev (struct dev_data *data) static void put_dev (struct dev_data *data)
{ {
if (likely (!atomic_dec_and_test (&data->count))) if (likely (!refcount_dec_and_test (&data->count)))
return; return;
/* needs no more cleanup */ /* needs no more cleanup */
BUG_ON (waitqueue_active (&data->wait)); BUG_ON (waitqueue_active (&data->wait));
...@@ -170,7 +171,7 @@ static struct dev_data *dev_new (void) ...@@ -170,7 +171,7 @@ static struct dev_data *dev_new (void)
if (!dev) if (!dev)
return NULL; return NULL;
dev->state = STATE_DEV_DISABLED; dev->state = STATE_DEV_DISABLED;
atomic_set (&dev->count, 1); refcount_set (&dev->count, 1);
spin_lock_init (&dev->lock); spin_lock_init (&dev->lock);
INIT_LIST_HEAD (&dev->epfiles); INIT_LIST_HEAD (&dev->epfiles);
init_waitqueue_head (&dev->wait); init_waitqueue_head (&dev->wait);
......
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