linux-kernel - Re: [PATCH] can: mcba_usb: fix memory leak in mcba

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Date:   Tue, 15 Jun 2021 09:33:19 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     Pavel Skripkin <paskripkin@...il.com>
Cc:     wg@...ndegger.com, davem@...emloft.net, linux-can@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzbot+57281c762a3922e14dfe@...kaller.appspotmail.com
Subject: Re: [PATCH] can: mcba_usb: fix memory leak in mcba_usb

On 10.06.2021 00:58:33, Pavel Skripkin wrote:
> Syzbot reported memory leak in SocketCAN driver
> for Microchip CAN BUS Analyzer Tool. The problem
> was in unfreed usb_coherent.
> 
> In mcba_usb_start() 20 coherent buffers are allocated
> and there is nothing, that frees them:
> 
> 	1) In callback function the urb is resubmitted and that's all
> 	2) In disconnect function urbs are simply killed, but
> 	   URB_FREE_BUFFER is not set (see mcba_usb_start)
>            and this flag cannot be used with coherent buffers.
> 
> Fail log:
> [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: device disconnected
> [ 1367.059384][ T8420] kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem)
> 
> So, all allocated buffers should be freed with usb_free_coherent()
> explicitly
> 
> NOTE:
> The same pattern for allocating and freeing coherent buffers
> is used in drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
> 
> Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
> Reported-and-tested-by: syzbot+57281c762a3922e14dfe@...kaller.appspotmail.com
> Signed-off-by: Pavel Skripkin <paskripkin@...il.com>

Applied to linux-can/testing.

Tnx,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
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