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Message-ID: <dd1c45ad-7af2-8df1-a3ab-0db99dd25934@wanadoo.fr>
Date: Fri, 3 Feb 2023 07:25:45 +0100
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Zheng Wang <zyytlz.wz@....com>, srini.raju@...elifi.com
Cc: kvalo@...nel.org, davem@...emloft.net, edumazet@...gle.com,
kuba@...nel.org, pabeni@...hat.com, linux-wireless@...r.kernel.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] wifi: plfxlc: fix potential NULL pointer dereference in
plfxlc_usb_wreq_async()
Le 03/02/2023 à 05:16, Zheng Wang a écrit :
> Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory
> allocated not to be NULL. But in some low-memory situation, it's still
> possible to return NULL. It'll pass urb as argument in
> usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference.
>
> Fix it by adding additional check.
>
> Note that, as a bug found by static analysis, it can be a false
> positive or hard to trigger.
>
> Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices")
>
> Signed-off-by: Zheng Wang <zyytlz.wz@....com>
> ---
> drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c
> index 76d0a778636a..ac149aa64908 100644
> --- a/drivers/net/wireless/purelifi/plfxlc/usb.c
> +++ b/drivers/net/wireless/purelifi/plfxlc/usb.c
> @@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer,
> struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC);
> int r;
>
> + if (!urb) {
> + r = -ENOMEM;
> + kfree(urb);
Hi,
why kfree() in such a case?
CJ
> + goto out;
> + }
> usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
> (void *)buffer, buffer_len, complete_fn, context);
>
> r = usb_submit_urb(urb, GFP_ATOMIC);
> +
> +out:
> if (r)
> dev_err(&udev->dev, "Async write submit failed (%d)\n", r);
>
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