linux-kernel - [PATCH AUTOSEL 4.19 095/206] Bluetooth: guard against controllers sending zero'd events

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Message-Id: <20200918020802.2065198-95-sashal@kernel.org>
Date:   Thu, 17 Sep 2020 22:06:11 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Alain Michaud <alainm@...omium.org>,
        Marcel Holtmann <marcel@...tmann.org>,
        Sasha Levin <sashal@...nel.org>,
        linux-bluetooth@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 095/206] Bluetooth: guard against controllers sending zero'd events

From: Alain Michaud <alainm@...omium.org>

[ Upstream commit 08bb4da90150e2a225f35e0f642cdc463958d696 ]

Some controllers have been observed to send zero'd events under some
conditions.  This change guards against this condition as well as adding
a trace to facilitate diagnosability of this condition.

Signed-off-by: Alain Michaud <alainm@...omium.org>
Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/bluetooth/hci_event.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 2b4a7cf03041b..ec6b3a87b3e7f 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5738,6 +5738,11 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 	u8 status = 0, event = hdr->evt, req_evt = 0;
 	u16 opcode = HCI_OP_NOP;
 
+	if (!event) {
+		bt_dev_warn(hdev, "Received unexpected HCI Event 00000000");
+		goto done;
+	}
+
 	if (hdev->sent_cmd && bt_cb(hdev->sent_cmd)->hci.req_event == event) {
 		struct hci_command_hdr *cmd_hdr = (void *) hdev->sent_cmd->data;
 		opcode = __le16_to_cpu(cmd_hdr->opcode);
@@ -5949,6 +5954,7 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 		req_complete_skb(hdev, status, opcode, orig_skb);
 	}
 
+done:
 	kfree_skb(orig_skb);
 	kfree_skb(skb);
 	hdev->stat.evt_rx++;
-- 
2.25.1