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Commit 1f64751a authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Greg Kroah-Hartman
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media: smsusb: better handle optional alignment 



commit a47686636d84eaec5c9c6e84bd5f96bed34d526d upstream.

Most Siano devices require an alignment for the response.

Changeset f3be52b0056a ("media: usb: siano: Fix general protection fault in smsusb")
changed the logic with gets such aligment, but it now produces a
sparce warning:

drivers/media/usb/siano/smsusb.c: In function 'smsusb_init_device':
drivers/media/usb/siano/smsusb.c:447:37: warning: 'in_maxp' may be used uninitialized in this function [-Wmaybe-uninitialized]
  447 |   dev->response_alignment = in_maxp - sizeof(struct sms_msg_hdr);
      |                             ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

The sparse message itself is bogus, but a broken (or fake) USB
eeprom could produce a negative value for response_alignment.

So, change the code in order to check if the result is not
negative.

Fixes: 31e0456de5be ("media: usb: siano: Fix general protection fault in smsusb")
CC: <stable@vger.kernel.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e6df98ca

drivers/media/usb/siano/smsusb.c

+4 −4
Original line number Diff line number Diff line
@@ -401,7 +401,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id) 
	struct smsusb_device_t *dev;

	void *mdev;

	int i, rc;

	int in_maxp = 0;

	int align = 0;



	/* create device object */

	dev = kzalloc(sizeof(struct smsusb_device_t), GFP_KERNEL);
@@ -419,14 +419,14 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id) 


		if (desc->bEndpointAddress & USB_DIR_IN) {

			dev->in_ep = desc->bEndpointAddress;

			in_maxp = usb_endpoint_maxp(desc);

			align = usb_endpoint_maxp(desc) - sizeof(struct sms_msg_hdr);

		} else {

			dev->out_ep = desc->bEndpointAddress;

		}

	}



	pr_debug("in_ep = %02x, out_ep = %02x\n", dev->in_ep, dev->out_ep);

	if (!dev->in_ep || !dev->out_ep) {	/* Missing endpoints? */

	if (!dev->in_ep || !dev->out_ep || align < 0) {  /* Missing endpoints? */

		smsusb_term_device(intf);

		return -ENODEV;

	}
@@ -445,7 +445,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id) 
		/* fall-thru */

	default:

		dev->buffer_size = USB2_BUFFER_SIZE;

		dev->response_alignment = in_maxp - sizeof(struct sms_msg_hdr);

		dev->response_alignment = align;



		params.flags |= SMS_DEVICE_FAMILY2;

		break;