[PATCH 4.2 068/124] NFC: nci: Fix incorrect data chaining when sending data

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Christophe Ricard <christophe.ricard@xxxxxxxxx>

commit 500c4ef02277eaadbfe20537f963b6221f6ac007 upstream.

When sending HCI data over NCI, cmd information should be
present only on the first packet.
Each packet shall be specifically allocated and sent to the
NCI layer.

Signed-off-by: Christophe Ricard <christophe-h.ricard@xxxxxx>
Signed-off-by: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/nfc/nci/hci.c |   20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

--- a/net/nfc/nci/hci.c
+++ b/net/nfc/nci/hci.c
@@ -146,18 +146,18 @@ static int nci_hci_send_data(struct nci_
 	if (!conn_info)
 		return -EPROTO;
 
-	skb = nci_skb_alloc(ndev, 2 + conn_info->max_pkt_payload_len +
+	i = 0;
+	skb = nci_skb_alloc(ndev, conn_info->max_pkt_payload_len +
 			    NCI_DATA_HDR_SIZE, GFP_KERNEL);
 	if (!skb)
 		return -ENOMEM;
 
-	skb_reserve(skb, 2 + NCI_DATA_HDR_SIZE);
+	skb_reserve(skb, NCI_DATA_HDR_SIZE + 2);
 	*skb_push(skb, 1) = data_type;
 
-	i = 0;
-	len = conn_info->max_pkt_payload_len;
-
 	do {
+		len = conn_info->max_pkt_payload_len;
+
 		/* If last packet add NCI_HFP_NO_CHAINING */
 		if (i + conn_info->max_pkt_payload_len -
 		    (skb->len + 1) >= data_len) {
@@ -177,9 +177,15 @@ static int nci_hci_send_data(struct nci_
 			return r;
 
 		i += len;
+
 		if (i < data_len) {
-			skb_trim(skb, 0);
-			skb_pull(skb, len);
+			skb = nci_skb_alloc(ndev,
+					    conn_info->max_pkt_payload_len +
+					    NCI_DATA_HDR_SIZE, GFP_KERNEL);
+			if (!skb)
+				return -ENOMEM;
+
+			skb_reserve(skb, NCI_DATA_HDR_SIZE + 1);
 		}
 	} while (i < data_len);
 


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