netdev - Re: [PATCH] Bluetooth: msft: fix null pointer deref on msft_monitor_device

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Message-Id: <5EE35A0B-5B1F-4ABA-986F-15F73A81141C@holtmann.org>
Date:   Sat, 22 Jan 2022 22:39:19 +0100
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Soenke Huster <soenke.huster@...oes.de>
Cc:     Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        BlueZ <linux-bluetooth@...r.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@...r.kernel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Bluetooth: msft: fix null pointer deref on
 msft_monitor_device_evt

Hi Soenke,

> msft_find_handle_data returns NULL if it can't find the handle.
> Therefore, handle_data must be checked, otherwise a null pointer
> is dereferenced.
> 
> Signed-off-by: Soenke Huster <soenke.huster@...oes.de>
> ---
> net/bluetooth/msft.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
> index 484540855863..d2cf92e834f7 100644
> --- a/net/bluetooth/msft.c
> +++ b/net/bluetooth/msft.c
> @@ -705,6 +705,9 @@ static void msft_monitor_device_evt(struct hci_dev *hdev, struct sk_buff *skb)
> 
> 	handle_data = msft_find_handle_data(hdev, ev->monitor_handle, false);
> 

scrap this empty line. The check can got right after the assignment.

> +	if (!handle_data)
> +		return;
> +
> 	switch (ev->addr_type) {
> 	case ADDR_LE_DEV_PUBLIC:
> 		addr_type = BDADDR_LE_PUBLIC;

Regards

Marcel