NFC: pn533: don't send USB data off of the stack

It's amazing that this driver ever worked, but now that x86 doesn't
allow USB data to be sent off of the stack, it really does not work at
all. Fix this up by properly allocating the data for the small
"commands" that get sent to the device off of the stack.

We do this for one command by having a whole urb just for ack messages,
as they can be submitted in interrupt context, so we can not use
usb_bulk_msg(). But the poweron command can sleep (and does), so use
usb_bulk_msg() for that transfer.

Reported-by: Carlos Manuel Santos <[e-mail]>
Cc: Samuel Ortiz <[e-mail]>
Cc: Stephen Hemminger <[e-mail]>
Cc: stable <[e-mail]>
Reviewed-by: Johan Hovold <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/nfc/pn533/usb.c

···
 	struct urb *out_urb;
 	struct urb *in_urb;
 
+	struct urb *ack_urb;
+	u8 *ack_buffer;
+
 	struct pn533 *priv;
 };
 
···
 	struct pn533_usb_phy *phy = dev->phy;
 	static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
 	/* spec 7.1.1.3:  Preamble, SoPC (2), ACK Code (2), Postamble */
-	int rc;
 
-	phy->out_urb->transfer_buffer = (u8 *)ack;
-	phy->out_urb->transfer_buffer_length = sizeof(ack);
-	rc = usb_submit_urb(phy->out_urb, flags);
+	if (!phy->ack_buffer) {
+		phy->ack_buffer = kmemdup(ack, sizeof(ack), flags);
+		if (!phy->ack_buffer)
+			return -ENOMEM;
+	}
 
-	return rc;
+	phy->ack_urb->transfer_buffer = phy->ack_buffer;
+	phy->ack_urb->transfer_buffer_length = sizeof(ack);
+	return usb_submit_urb(phy->ack_urb, flags);
 }
 
 static int pn533_usb_send_frame(struct pn533 *dev,
···
 	/* Power on th reader (CCID cmd) */
 	u8 cmd[10] = {PN533_ACR122_PC_TO_RDR_ICCPOWERON,
 		      0, 0, 0, 0, 0, 0, 3, 0, 0};
+	char *buffer;
+	int transferred;
 	int rc;
 	void *cntx;
 	struct pn533_acr122_poweron_rdr_arg arg;
 
 	dev_dbg(&phy->udev->dev, "%s\n", __func__);
+
+	buffer = kmemdup(cmd, sizeof(cmd), GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
 
 	init_completion(&arg.done);
 	cntx = phy->in_urb->context;  /* backup context */
···
 	phy->in_urb->complete = pn533_acr122_poweron_rdr_resp;
 	phy->in_urb->context = &arg;
 
-	phy->out_urb->transfer_buffer = cmd;
-	phy->out_urb->transfer_buffer_length = sizeof(cmd);
-
 	print_hex_dump_debug("ACR122 TX: ", DUMP_PREFIX_NONE, 16, 1,
 		       cmd, sizeof(cmd), false);
 
-	rc = usb_submit_urb(phy->out_urb, GFP_KERNEL);
-	if (rc) {
+	rc = usb_bulk_msg(phy->udev, phy->out_urb->pipe, buffer, sizeof(cmd),
+			  &transferred, 0);
+	kfree(buffer);
+	if (rc || (transferred != sizeof(cmd))) {
 		nfc_err(&phy->udev->dev,
 			"Reader power on cmd error %d\n", rc);
 		return rc;
···
 
 	phy->in_urb = usb_alloc_urb(0, GFP_KERNEL);
 	phy->out_urb = usb_alloc_urb(0, GFP_KERNEL);
+	phy->ack_urb = usb_alloc_urb(0, GFP_KERNEL);
 
-	if (!phy->in_urb || !phy->out_urb)
+	if (!phy->in_urb || !phy->out_urb || !phy->ack_urb)
 		goto error;
 
 	usb_fill_bulk_urb(phy->in_urb, phy->udev,
···
 	usb_fill_bulk_urb(phy->out_urb, phy->udev,
 			  usb_sndbulkpipe(phy->udev, out_endpoint),
 			  NULL, 0, pn533_send_complete, phy);
-
+	usb_fill_bulk_urb(phy->ack_urb, phy->udev,
+			  usb_sndbulkpipe(phy->udev, out_endpoint),
+			  NULL, 0, pn533_send_complete, phy);
 
 	switch (id->driver_info) {
 	case PN533_DEVICE_STD:
···
 error:
 	usb_free_urb(phy->in_urb);
 	usb_free_urb(phy->out_urb);
+	usb_free_urb(phy->ack_urb);
 	usb_put_dev(phy->udev);
 	kfree(in_buf);
 
···
 
 	usb_kill_urb(phy->in_urb);
 	usb_kill_urb(phy->out_urb);
+	usb_kill_urb(phy->ack_urb);
 
 	kfree(phy->in_urb->transfer_buffer);
 	usb_free_urb(phy->in_urb);
 	usb_free_urb(phy->out_urb);
+	usb_free_urb(phy->ack_urb);
+	kfree(phy->ack_buffer);
 
 	nfc_info(&interface->dev, "NXP PN533 NFC device disconnected\n");
 }