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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [PATCH v2 07/10] Bluetooth: HCI: Use skb_pull to parse LE Metaevents
Date:   Mon, 19 Apr 2021 10:12:54 -0700
Message-Id: <20210419171257.3865181-8-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 LE Metaevents received have the minimum
required length.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 net/bluetooth/hci_event.c | 75 +++++++++++++++++++++++++++++++++------
 1 file changed, 64 insertions(+), 11 deletions(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 9776c395412c..dc39861f4da6 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -78,6 +78,18 @@ static void *hci_cc_skb_pull(struct hci_dev *hdev, struct sk_buff *skb,
 	return data;
 }
 
+static void *hci_le_ev_skb_pull(struct hci_dev *hdev, struct sk_buff *skb,
+				u8 ev, size_t len)
+{
+	void *data;
+
+	data = hci_skb_pull(skb, len);
+	if (!data)
+		bt_dev_err(hdev, "Malformed LE Event: 0x%2.2x", ev);
+
+	return data;
+}
+
 static void hci_cc_inquiry_cancel(struct hci_dev *hdev, struct sk_buff *skb,
 				  u8 *new_status)
 {
@@ -5862,7 +5874,12 @@ static void le_conn_complete_evt(struct hci_dev *hdev, u8 status,
 
 static void hci_le_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hci_ev_le_conn_complete *ev = (void *) skb->data;
+	struct hci_ev_le_conn_complete *ev;
+
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_CONN_COMPLETE,
+				sizeof(*ev));
+	if (!ev)
+		return;
 
 	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 
@@ -5876,7 +5893,12 @@ static void hci_le_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 static void hci_le_enh_conn_complete_evt(struct hci_dev *hdev,
 					 struct sk_buff *skb)
 {
-	struct hci_ev_le_enh_conn_complete *ev = (void *) skb->data;
+	struct hci_ev_le_enh_conn_complete *ev;
+
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_ENHANCED_CONN_COMPLETE,
+				sizeof(*ev));
+	if (!ev)
+		return;
 
 	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 
@@ -5894,9 +5916,14 @@ static void hci_le_enh_conn_complete_evt(struct hci_dev *hdev,
 
 static void hci_le_ext_adv_term_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hci_evt_le_ext_adv_set_term *ev = (void *) skb->data;
+	struct hci_evt_le_ext_adv_set_term *ev;
 	struct hci_conn *conn;
 
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_EXT_ADV_SET_TERM,
+				sizeof(*ev));
+	if (!ev)
+		return;
+
 	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 
 	if (ev->status)
@@ -5923,9 +5950,14 @@ static void hci_le_ext_adv_term_evt(struct hci_dev *hdev, struct sk_buff *skb)
 static void hci_le_conn_update_complete_evt(struct hci_dev *hdev,
 					    struct sk_buff *skb)
 {
-	struct hci_ev_le_conn_update_complete *ev = (void *) skb->data;
+	struct hci_ev_le_conn_update_complete *ev;
 	struct hci_conn *conn;
 
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_CONN_UPDATE_COMPLETE,
+				sizeof(*ev));
+	if (!ev)
+		return;
+
 	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 
 	if (ev->status)
@@ -6340,9 +6372,14 @@ static void hci_le_ext_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
 static void hci_le_remote_feat_complete_evt(struct hci_dev *hdev,
 					    struct sk_buff *skb)
 {
-	struct hci_ev_le_remote_feat_complete *ev = (void *)skb->data;
+	struct hci_ev_le_remote_feat_complete *ev;
 	struct hci_conn *conn;
 
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_EXT_ADV_REPORT,
+				sizeof(*ev));
+	if (!ev)
+		return;
+
 	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 
 	hci_dev_lock(hdev);
@@ -6381,12 +6418,16 @@ static void hci_le_remote_feat_complete_evt(struct hci_dev *hdev,
 
 static void hci_le_ltk_request_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hci_ev_le_ltk_req *ev = (void *) skb->data;
+	struct hci_ev_le_ltk_req *ev;
 	struct hci_cp_le_ltk_reply cp;
 	struct hci_cp_le_ltk_neg_reply neg;
 	struct hci_conn *conn;
 	struct smp_ltk *ltk;
 
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_LTK_REQ, sizeof(*ev));
+	if (!ev)
+		return;
+
 	BT_DBG("%s handle 0x%4.4x", hdev->name, __le16_to_cpu(ev->handle));
 
 	hci_dev_lock(hdev);
@@ -6458,11 +6499,16 @@ static void send_conn_param_neg_reply(struct hci_dev *hdev, u16 handle,
 static void hci_le_remote_conn_param_req_evt(struct hci_dev *hdev,
 					     struct sk_buff *skb)
 {
-	struct hci_ev_le_remote_conn_param_req *ev = (void *) skb->data;
+	struct hci_ev_le_remote_conn_param_req *ev;
 	struct hci_cp_le_conn_param_req_reply cp;
 	struct hci_conn *hcon;
 	u16 handle, min, max, latency, timeout;
 
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_REMOTE_CONN_PARAM_REQ,
+				sizeof(*ev));
+	if (!ev)
+		return;
+
 	handle = le16_to_cpu(ev->handle);
 	min = le16_to_cpu(ev->interval_min);
 	max = le16_to_cpu(ev->interval_max);
@@ -6535,9 +6581,14 @@ static void hci_le_direct_adv_report_evt(struct hci_dev *hdev,
 
 static void hci_le_phy_update_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hci_ev_le_phy_update_complete *ev = (void *) skb->data;
+	struct hci_ev_le_phy_update_complete *ev;
 	struct hci_conn *conn;
 
+	ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_PHY_UPDATE_COMPLETE,
+				sizeof(*ev));
+	if (ev)
+		return;
+
 	BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
 
 	if (ev->status)
@@ -6558,11 +6609,13 @@ static void hci_le_phy_update_evt(struct hci_dev *hdev, struct sk_buff *skb)
 
 static void hci_le_meta_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
-	struct hci_ev_le_meta *le_ev = (void *) skb->data;
+	struct hci_ev_le_meta *ev;
 
-	skb_pull(skb, sizeof(*le_ev));
+	ev = hci_ev_skb_pull(hdev, skb, HCI_EV_LE_META, sizeof(*ev));
+	if (!ev)
+		return;
 
-	switch (le_ev->subevent) {
+	switch (ev->subevent) {
 	case HCI_EV_LE_CONN_COMPLETE:
 		hci_le_conn_complete_evt(hdev, skb);
 		break;
-- 
2.30.2