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: NCarlos Manuel Santos <cmmpsantos@gmail.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nfc/pn533/usb.c

@@ -62,6 +62,9 @@ struct pn533_usb_phy {
 	struct urb *out_urb;
 	struct urb *in_urb;
 
+	struct urb *ack_urb;
+	u8 *ack_buffer;
+
 	struct pn533 *priv;
 };
 
@@ -150,13 +153,16 @@ static int pn533_usb_send_ack(struct pn533 *dev, gfp_t flags)
 	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,
@@ -375,26 +381,31 @@ static int pn533_acr122_poweron_rdr(struct pn533_usb_phy *phy)
 	/* 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;
@@ -490,8 +501,9 @@ static int pn533_usb_probe(struct usb_interface *interface,
 
 	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,
@@ -501,7 +513,9 @@ static int pn533_usb_probe(struct usb_interface *interface,
 	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:
@@ -554,6 +568,7 @@ static int pn533_usb_probe(struct usb_interface *interface,
 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);
 
@@ -573,10 +588,13 @@ static void pn533_usb_disconnect(struct usb_interface *interface)
 
 	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");
 }