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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [PATCH 05/10] Bluetooth: HCI: Use skb_pull to parse Inquiry Result with RSSI event
Date:   Fri, 16 Apr 2021 14:18:18 -0700
Message-Id: <20210416211823.3776677-6-luiz.dentz@gmail.com>
In-Reply-To: <20210416211823.3776677-1-luiz.dentz@gmail.com>
References: <20210416211823.3776677-1-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 Inquiry Result with RSSI events
received have the minimum required length.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci.h | 12 +++++++++--
 net/bluetooth/hci_event.c   | 40 +++++++++++++++++++++----------------
 2 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index b65205b4d830..53e16ad79698 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -2076,7 +2076,7 @@ struct hci_ev_pscan_rep_mode {
 } __packed;
 
 #define HCI_EV_INQUIRY_RESULT_WITH_RSSI	0x22
-struct inquiry_info_with_rssi {
+struct inquiry_info_rssi {
 	bdaddr_t bdaddr;
 	__u8     pscan_rep_mode;
 	__u8     pscan_period_mode;
@@ -2084,7 +2084,7 @@ struct inquiry_info_with_rssi {
 	__le16   clock_offset;
 	__s8     rssi;
 } __packed;
-struct inquiry_info_with_rssi_and_pscan_mode {
+struct inquiry_info_rssi_pscan {
 	bdaddr_t bdaddr;
 	__u8     pscan_rep_mode;
 	__u8     pscan_period_mode;
@@ -2093,6 +2093,14 @@ struct inquiry_info_with_rssi_and_pscan_mode {
 	__le16   clock_offset;
 	__s8     rssi;
 } __packed;
+struct hci_ev_inquiry_result_rssi {
+	__u8     num;
+	struct inquiry_info_rssi info[];
+} __packed;
+struct hci_ev_inquiry_result_rssi_pscan {
+	__u8     num;
+	struct inquiry_info_rssi_pscan info[];
+} __packed;
 
 #define HCI_EV_REMOTE_EXT_FEATURES	0x23
 struct hci_ev_remote_ext_features {
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 8fa11e99b1cb..d0e7744e9e7e 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4721,12 +4721,21 @@ static void hci_pscan_rep_mode_evt(struct hci_dev *hdev, struct sk_buff *skb)
 static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 					     struct sk_buff *skb)
 {
+	union {
+		struct hci_ev_inquiry_result_rssi *res1;
+		struct hci_ev_inquiry_result_rssi_pscan *res2;
+	} *ev;
 	struct inquiry_data data;
-	int num_rsp = *((__u8 *) skb->data);
+	int i;
 
-	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
+	ev = hci_ev_skb_pull(hdev, skb, HCI_EV_INQUIRY_RESULT_WITH_RSSI,
+			     sizeof(*ev));
+	if (!ev)
+		return;
+
+	BT_DBG("%s num_rsp %d", hdev->name, ev->res1->num);
 
-	if (!num_rsp)
+	if (!ev->res1->num)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
@@ -4734,16 +4743,13 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 
 	hci_dev_lock(hdev);
 
-	if ((skb->len - 1) / num_rsp != sizeof(struct inquiry_info_with_rssi)) {
-		struct inquiry_info_with_rssi_and_pscan_mode *info;
-		info = (void *) (skb->data + 1);
+	if (skb->len == flex_array_size(ev, res2->info, ev->res2->num)) {
+		struct inquiry_info_rssi_pscan *info;
 
-		if (skb->len < num_rsp * sizeof(*info) + 1)
-			goto unlock;
-
-		for (; num_rsp; num_rsp--, info++) {
+		for (i = 0; i < ev->res2->num; i++) {
 			u32 flags;
 
+			info = &ev->res2->info[i];
 			bacpy(&data.bdaddr, &info->bdaddr);
 			data.pscan_rep_mode	= info->pscan_rep_mode;
 			data.pscan_period_mode	= info->pscan_period_mode;
@@ -4759,15 +4765,13 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 					  info->dev_class, info->rssi,
 					  flags, NULL, 0, NULL, 0);
 		}
-	} else {
-		struct inquiry_info_with_rssi *info = (void *) (skb->data + 1);
+	} else if (skb->len == flex_array_size(ev, res1->info, ev->res1->num)) {
+		struct inquiry_info_rssi *info;
 
-		if (skb->len < num_rsp * sizeof(*info) + 1)
-			goto unlock;
-
-		for (; num_rsp; num_rsp--, info++) {
+		for (i = 0; i < ev->res1->num; i++) {
 			u32 flags;
 
+			info = &ev->res1->info[i];
 			bacpy(&data.bdaddr, &info->bdaddr);
 			data.pscan_rep_mode	= info->pscan_rep_mode;
 			data.pscan_period_mode	= info->pscan_period_mode;
@@ -4783,9 +4787,11 @@ static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev,
 					  info->dev_class, info->rssi,
 					  flags, NULL, 0, NULL, 0);
 		}
+	} else {
+		bt_dev_err(hdev, "Malformed HCI Event: 0x%2.2x",
+			   HCI_EV_INQUIRY_RESULT_WITH_RSSI);
 	}
 
-unlock:
 	hci_dev_unlock(hdev);
 }
 
-- 
2.30.2