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: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -191,7 +191,7 @@ enum ep_state {
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struct ep_data {
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struct mutex lock;
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enum ep_state state;
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atomic_t count;
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refcount_t count;
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struct dev_data *dev;
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/* must hold dev->lock before accessing ep or req */
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struct usb_ep *ep;
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@ -206,12 +206,12 @@ struct ep_data {
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static inline void get_ep (struct ep_data *data)
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{
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atomic_inc (&data->count);
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refcount_inc (&data->count);
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}
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static void put_ep (struct ep_data *data)
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{
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if (likely (!atomic_dec_and_test (&data->count)))
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if (likely (!refcount_dec_and_test (&data->count)))
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return;
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put_dev (data->dev);
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/* needs no more cleanup */
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@ -1562,7 +1562,7 @@ static int activate_ep_files (struct dev_data *dev)
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init_waitqueue_head (&data->wait);
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strncpy (data->name, ep->name, sizeof (data->name) - 1);
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atomic_set (&data->count, 1);
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refcount_set (&data->count, 1);
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data->dev = dev;
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get_dev (dev);
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