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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [PATCH v2 06/10] Bluetooth: HCI: Use skb_pull to parse Extended Inquiry Result event
Date:   Mon, 19 Apr 2021 10:12:53 -0700
Message-Id: <20210419171257.3865181-7-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 Extended Inquiry Result events
received have the minimum required length.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci.h |  5 +++++
 net/bluetooth/hci_event.c   | 20 +++++++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 53e16ad79698..f416ad71fd2d 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -2155,6 +2155,11 @@ struct extended_inquiry_info {
 	__u8     data[240];
 } __packed;
 
+struct hci_ev_ext_inquiry_result {
+	__u8     num;
+	struct extended_inquiry_info info[];
+} __packed;
+
 #define HCI_EV_KEY_REFRESH_COMPLETE	0x30
 struct hci_ev_key_refresh_complete {
 	__u8	status;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 05d680a5f9c3..9776c395412c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4968,14 +4968,23 @@ static inline size_t eir_get_length(u8 *eir, size_t eir_len)
 static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,
 					    struct sk_buff *skb)
 {
+	struct hci_ev_ext_inquiry_result *ev;
 	struct inquiry_data data;
-	struct extended_inquiry_info *info = (void *) (skb->data + 1);
-	int num_rsp = *((__u8 *) skb->data);
 	size_t eir_len;
+	int i;
 
-	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
+	ev = hci_ev_skb_pull(hdev, skb, HCI_EV_EXTENDED_INQUIRY_RESULT,
+			     sizeof(*ev));
+	if (!ev)
+		return;
 
-	if (!num_rsp || skb->len < num_rsp * sizeof(*info) + 1)
+	if (!hci_ev_skb_pull(hdev, skb, HCI_EV_EXTENDED_INQUIRY_RESULT,
+			     flex_array_size(ev, info, ev->num)))
+		return;
+
+	BT_DBG("%s num %d", hdev->name, ev->num);
+
+	if (!ev->num)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
@@ -4983,7 +4992,8 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,
 
 	hci_dev_lock(hdev);
 
-	for (; num_rsp; num_rsp--, info++) {
+	for (i = 0; i < ev->num; i++) {
+		struct extended_inquiry_info *info = &ev->info[i];
 		u32 flags;
 		bool name_known;
 
-- 
2.30.2