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Commit e7ca00f3 authored by Krishna Kurapati's avatar Krishna Kurapati Committed by Greg Kroah-Hartman
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usb: gadget: ncm: Handle decoding of multiple NTB's in unwrap call 



commit 427694cfaafa565a3db5c5ea71df6bc095dca92f upstream.

When NCM is used with hosts like Windows PC, it is observed that there are
multiple NTB's contained in one usb request giveback. Since the driver
unwraps the obtained request data assuming only one NTB is present, we
loose the subsequent NTB's present resulting in data loss.

Fix this by checking the parsed block length with the obtained data
length in usb request and continue parsing after the last byte of current
NTB.

Cc: stable@vger.kernel.org
Fixes: 9f6ce424 ("usb: gadget: f_ncm.c added")
Signed-off-by: default avatarKrishna Kurapati <quic_kriskura@quicinc.com>
Reviewed-by: default avatarMaciej Żenczykowski <maze@google.com>
Link: https://lore.kernel.org/r/20230927105858.12950-1-quic_kriskura@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1e4414c3

drivers/usb/gadget/function/f_ncm.c

+19 −7
Original line number Diff line number Diff line
@@ -1180,7 +1180,8 @@ static int ncm_unwrap_ntb(struct gether *port, 
			  struct sk_buff_head *list)

{

	struct f_ncm	*ncm = func_to_ncm(&port->func);

	__le16		*tmp = (void *) skb->data;

	unsigned char	*ntb_ptr = skb->data;

	__le16		*tmp;

	unsigned	index, index2;

	int		ndp_index;

	unsigned	dg_len, dg_len2;
@@ -1193,6 +1194,10 @@ static int ncm_unwrap_ntb(struct gether *port, 
	const struct ndp_parser_opts *opts = ncm->parser_opts;

	unsigned	crc_len = ncm->is_crc ? sizeof(uint32_t) : 0;

	int		dgram_counter;

	int		to_process = skb->len;



parse_ntb:

	tmp = (__le16 *)ntb_ptr;



	/* dwSignature */

	if (get_unaligned_le32(tmp) != opts->nth_sign) {
@@ -1239,7 +1244,7 @@ static int ncm_unwrap_ntb(struct gether *port, 
		 * walk through NDP

		 * dwSignature

		 */

		tmp = (void *)(skb->data + ndp_index);

		tmp = (__le16 *)(ntb_ptr + ndp_index);

		if (get_unaligned_le32(tmp) != ncm->ndp_sign) {

			INFO(port->func.config->cdev, "Wrong NDP SIGN\n");

			goto err;
@@ -1296,11 +1301,11 @@ static int ncm_unwrap_ntb(struct gether *port, 
			if (ncm->is_crc) {

				uint32_t crc, crc2;



				crc = get_unaligned_le32(skb->data +

				crc = get_unaligned_le32(ntb_ptr +

							 index + dg_len -

							 crc_len);

				crc2 = ~crc32_le(~0,

						 skb->data + index,

						 ntb_ptr + index,

						 dg_len - crc_len);

				if (crc != crc2) {

					INFO(port->func.config->cdev,
@@ -1327,7 +1332,7 @@ static int ncm_unwrap_ntb(struct gether *port, 
							 dg_len - crc_len);

			if (skb2 == NULL)

				goto err;

			skb_put_data(skb2, skb->data + index,

			skb_put_data(skb2, ntb_ptr + index,

				     dg_len - crc_len);



			skb_queue_tail(list, skb2);
@@ -1340,10 +1345,17 @@ static int ncm_unwrap_ntb(struct gether *port, 
		} while (ndp_len > 2 * (opts->dgram_item_len * 2));

	} while (ndp_index);



	dev_consume_skb_any(skb);



	VDBG(port->func.config->cdev,

	     "Parsed NTB with %d frames\n", dgram_counter);



	to_process -= block_len;

	if (to_process != 0) {

		ntb_ptr = (unsigned char *)(ntb_ptr + block_len);

		goto parse_ntb;

	}



	dev_consume_skb_any(skb);



	return 0;

err:

	skb_queue_purge(list);