Commit fb1f16d7 authored by Linyu Yuan's avatar Linyu Yuan Committed by Greg Kroah-Hartman
Browse files

usb: gadget: f_fs: change ep->status safe in ffs_epfile_io() 



If a task read/write data in blocking mode, it will wait the completion
in ffs_epfile_io(), if function unbind occurs, ffs_func_unbind() will
kfree ffs ep, once the task wake up, it still dereference the ffs ep to
obtain the request status.

Fix it by moving the request status to io_data which is stack-safe.

Cc: <stable@vger.kernel.org> # 5.15
Reported-by: default avatarMichael Wu <michael@allwinnertech.com>
Tested-by: default avatarMichael Wu <michael@allwinnertech.com>
Reviewed-by: default avatarJohn Keeping <john@metanate.com>
Signed-off-by: default avatarLinyu Yuan <quic_linyyuan@quicinc.com>
Link: https://lore.kernel.org/r/1654863478-26228-2-git-send-email-quic_linyyuan@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 802dcafc

drivers/usb/gadget/function/f_fs.c

+19 −15
Original line number Diff line number Diff line
@@ -122,8 +122,6 @@ struct ffs_ep { 
	struct usb_endpoint_descriptor	*descs[3];



	u8				num;



	int				status;	/* P: epfile->mutex */

};



struct ffs_epfile {
@@ -227,6 +225,9 @@ struct ffs_io_data { 
	bool use_sg;



	struct ffs_data *ffs;



	int status;

	struct completion done;

};



struct ffs_desc_helper {
@@ -707,12 +708,15 @@ static const struct file_operations ffs_ep0_operations = { 


static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)

{

	struct ffs_io_data *io_data = req->context;



	ENTER();

	if (req->context) {

		struct ffs_ep *ep = _ep->driver_data;

		ep->status = req->status ? req->status : req->actual;

		complete(req->context);

	}

	if (req->status)

		io_data->status = req->status;

	else

		io_data->status = req->actual;



	complete(&io_data->done);

}



static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
@@ -1050,7 +1054,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) 
		WARN(1, "%s: data_len == -EINVAL\n", __func__);

		ret = -EINVAL;

	} else if (!io_data->aio) {

		DECLARE_COMPLETION_ONSTACK(done);

		bool interrupted = false;



		req = ep->req;
@@ -1066,7 +1069,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) 


		io_data->buf = data;



		req->context  = &done;

		init_completion(&io_data->done);

		req->context  = io_data;

		req->complete = ffs_epfile_io_complete;



		ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
@@ -1075,7 +1079,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) 


		spin_unlock_irq(&epfile->ffs->eps_lock);



		if (wait_for_completion_interruptible(&done)) {

		if (wait_for_completion_interruptible(&io_data->done)) {

			/*

			 * To avoid race condition with ffs_epfile_io_complete,

			 * dequeue the request first then check
@@ -1083,17 +1087,17 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) 
			 * condition with req->complete callback.

			 */

			usb_ep_dequeue(ep->ep, req);

			wait_for_completion(&done);

			interrupted = ep->status < 0;

			wait_for_completion(&io_data->done);

			interrupted = io_data->status < 0;

		}



		if (interrupted)

			ret = -EINTR;

		else if (io_data->read && ep->status > 0)

			ret = __ffs_epfile_read_data(epfile, data, ep->status,

		else if (io_data->read && io_data->status > 0)

			ret = __ffs_epfile_read_data(epfile, data, io_data->status,

						     &io_data->data);

		else

			ret = ep->status;

			ret = io_data->status;

		goto error_mutex;

	} else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {

		ret = -ENOMEM;