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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [PATCH v2 03/10] Bluetooth: HCI: Use skb_pull to parse Number of Complete Packets event
Date:   Mon, 19 Apr 2021 10:12:50 -0700
Message-Id: <20210419171257.3865181-4-luiz.dentz@gmail.com>
In-Reply-To: <20210419171257.3865181-1-luiz.dentz@gmail.com>
References: <20210419171257.3865181-1-luiz.dentz@gmail.com>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This uses skb_pull to check the Number of Complete Packets events
received have the minimum required length.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci.h |  2 +-
 net/bluetooth/hci_event.c   | 20 +++++++++++---------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index f1f505355e81..9251ae3a2ce0 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -2021,7 +2021,7 @@ struct hci_comp_pkts_info {
 } __packed;
 
 struct hci_ev_num_comp_pkts {
-	__u8     num_hndl;
+	__u8     num;
 	struct hci_comp_pkts_info handles[];
 } __packed;
 
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index cc2d68389edc..c353dfafb04c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4264,23 +4264,25 @@ static void hci_role_change_evt(struct hci_dev *hdev, struct sk_buff *skb)
 
 static void hci_num_comp_pkts_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hci_ev_num_comp_pkts *ev = (void *) skb->data;
+	struct hci_ev_num_comp_pkts *ev;
 	int i;
 
-	if (hdev->flow_ctl_mode != HCI_FLOW_CTL_MODE_PACKET_BASED) {
-		bt_dev_err(hdev, "wrong event for mode %d", hdev->flow_ctl_mode);
+	ev = hci_ev_skb_pull(hdev, skb, HCI_EV_NUM_COMP_PKTS, sizeof(*ev));
+	if (!ev)
 		return;
-	}
 
-	if (skb->len < sizeof(*ev) ||
-	    skb->len < struct_size(ev, handles, ev->num_hndl)) {
-		BT_DBG("%s bad parameters", hdev->name);
+	if (!hci_ev_skb_pull(hdev, skb, HCI_EV_NUM_COMP_PKTS,
+			     flex_array_size(ev, handles, ev->num)))
+		return;
+
+	if (hdev->flow_ctl_mode != HCI_FLOW_CTL_MODE_PACKET_BASED) {
+		bt_dev_err(hdev, "wrong event for mode %d", hdev->flow_ctl_mode);
 		return;
 	}
 
-	BT_DBG("%s num_hndl %d", hdev->name, ev->num_hndl);
+	BT_DBG("%s num %d", hdev->name, ev->num);
 
-	for (i = 0; i < ev->num_hndl; i++) {
+	for (i = 0; i < ev->num; i++) {
 		struct hci_comp_pkts_info *info = &ev->handles[i];
 		struct hci_conn *conn;
 		__u16  handle, count;
-- 
2.30.2