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: 9f6ce4240a2b ("usb: gadget: f_ncm.c added") Signed-off-by: Krishna Kurapati quic_kriskura@quicinc.com --- Changes in v3: Removed explicit typecast for ntb_ptr

drivers/usb/gadget/function/f_ncm.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c index 424bb3b666db..9512cec662c8 100644 --- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -1171,7 +1171,8 @@ 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; @@ -1184,6 +1185,10 @@ 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 = (void *)ntb_ptr;

/* dwSignature */ if (get_unaligned_le32(tmp) != opts->nth_sign) { @@ -1230,7 +1235,7 @@ static int ncm_unwrap_ntb(struct gether *port, * walk through NDP * dwSignature */ - tmp = (void *)(skb->data + ndp_index); + tmp = (void *)(ntb_ptr + ndp_index); if (get_unaligned_le32(tmp) != ncm->ndp_sign) { INFO(port->func.config->cdev, "Wrong NDP SIGN\n"); goto err; @@ -1287,11 +1292,11 @@ 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, @@ -1318,7 +1323,7 @@ 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); @@ -1331,10 +1336,17 @@ 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);