FAILED: patch "[PATCH] can: m_can: m_can_tx_handler(): fix use after free of skb" failed to apply to 5.10-stable tree

FAILED: patch "[PATCH] can: m_can: m_can_tx_handler(): fix use after free of skb" failed to apply to 5.10-stable tree

[gregkh]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2e8e79c416aae1de224c0f1860f2e3350fa171f8 Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Thu, 17 Mar 2022 08:57:35 +0100
Subject: [PATCH] can: m_can: m_can_tx_handler(): fix use after free of skb

can_put_echo_skb() will clone skb then free the skb. Move the
can_put_echo_skb() for the m_can version 3.0.x directly before the
start of the xmit in hardware, similar to the 3.1.x branch.

Fixes: 80646733f11c ("can: m_can: update to support CAN FD features")
Link: https://lore.kernel.org/all/20220317081305.739554-1-mkl@pengutronix.de
Cc: stable@vger.kernel.org
Reported-by: Hangyu Hua <hbh25y@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 1a4b56f6fa8c..b3b5bc1c803b 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1637,8 +1637,6 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
 		if (err)
 			goto out_fail;
 
-		can_put_echo_skb(skb, dev, 0, 0);
-
 		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) {
 			cccr = m_can_read(cdev, M_CAN_CCCR);
 			cccr &= ~CCCR_CMR_MASK;
@@ -1655,6 +1653,9 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
 			m_can_write(cdev, M_CAN_CCCR, cccr);
 		}
 		m_can_write(cdev, M_CAN_TXBTIE, 0x1);
+
+		can_put_echo_skb(skb, dev, 0, 0);
+
 		m_can_write(cdev, M_CAN_TXBAR, 0x1);
 		/* End of xmit function for version 3.0.x */
 	} else {

Re: FAILED: patch "[PATCH] can: m_can: m_can_tx_handler(): fix use after free of skb" failed to apply to 5.10-stable tree

[Marc Kleine-Budde]

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On 01.04.2022 14:02:18, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.10-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

Here you are...or...it should show up here sooner or later:
https://lore.kernel.org/all/20220404190830.1241263-1-mkl@pengutronix.de

regards,
Marc

> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From 2e8e79c416aae1de224c0f1860f2e3350fa171f8 Mon Sep 17 00:00:00 2001
> From: Marc Kleine-Budde <mkl@pengutronix.de>
> Date: Thu, 17 Mar 2022 08:57:35 +0100
> Subject: [PATCH] can: m_can: m_can_tx_handler(): fix use after free of skb
> 
> can_put_echo_skb() will clone skb then free the skb. Move the
> can_put_echo_skb() for the m_can version 3.0.x directly before the
> start of the xmit in hardware, similar to the 3.1.x branch.
> 
> Fixes: 80646733f11c ("can: m_can: update to support CAN FD features")
> Link: https://lore.kernel.org/all/20220317081305.739554-1-mkl@pengutronix.de
> Cc: stable@vger.kernel.org
> Reported-by: Hangyu Hua <hbh25y@gmail.com>
> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
> 
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index 1a4b56f6fa8c..b3b5bc1c803b 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
> @@ -1637,8 +1637,6 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
>  		if (err)
>  			goto out_fail;
>  
> -		can_put_echo_skb(skb, dev, 0, 0);
> -
>  		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) {
>  			cccr = m_can_read(cdev, M_CAN_CCCR);
>  			cccr &= ~CCCR_CMR_MASK;
> @@ -1655,6 +1653,9 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)
>  			m_can_write(cdev, M_CAN_CCCR, cccr);
>  		}
>  		m_can_write(cdev, M_CAN_TXBTIE, 0x1);
> +
> +		can_put_echo_skb(skb, dev, 0, 0);
> +
>  		m_can_write(cdev, M_CAN_TXBAR, 0x1);
>  		/* End of xmit function for version 3.0.x */
>  	} else {
> 
> 

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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