* [PATCH v2] can: m_can: m_can_tx_handler(): fix use after free of skb
@ 2022-03-17 8:13 Marc Kleine-Budde
2022-03-17 10:41 ` Hangyu Hua
0 siblings, 1 reply; 2+ messages in thread
From: Marc Kleine-Budde @ 2022-03-17 8:13 UTC (permalink / raw)
To: linux-can; +Cc: Marc Kleine-Budde, Hangyu Hua
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.
Reported-by: Hangyu Hua <hbh25y@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
Hello,
picking up Hangyu Hua's work from:
| https://lore.kernel.org/all/20220317030143.14668-1-hbh25y@gmail.com/
Instead of using a temporary variable, move the can_put_echo_skb() instead.
regads,
Marc
drivers/net/can/m_can/m_can.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
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 {
--
2.35.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] can: m_can: m_can_tx_handler(): fix use after free of skb
2022-03-17 8:13 [PATCH v2] can: m_can: m_can_tx_handler(): fix use after free of skb Marc Kleine-Budde
@ 2022-03-17 10:41 ` Hangyu Hua
0 siblings, 0 replies; 2+ messages in thread
From: Hangyu Hua @ 2022-03-17 10:41 UTC (permalink / raw)
To: Marc Kleine-Budde, linux-can
I agree with you.
By the way, i find two similar questions about can_put_echo_skb. I hope
you can also check them out:
mcba_usb:
https://lore.kernel.org/all/20220311080208.45047-1-hbh25y@gmail.com/
usb_8dev:
https://lore.kernel.org/all/20220311080614.45229-1-hbh25y@gmail.com/
They are the same issue as the following patches:
https://lore.kernel.org/all/20220228083639.38183-1-hbh25y@gmail.com/
Thanks,
Hangyu Hua
On 2022/3/17 16:13, Marc Kleine-Budde wrote:
> 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.
>
> Reported-by: Hangyu Hua <hbh25y@gmail.com>
> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
> ---
>
> Hello,
>
> picking up Hangyu Hua's work from:
>
> | https://lore.kernel.org/all/20220317030143.14668-1-hbh25y@gmail.com/
>
> Instead of using a temporary variable, move the can_put_echo_skb() instead.
>
> regads,
> Marc
>
> drivers/net/can/m_can/m_can.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> 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 {
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-03-17 8:13 [PATCH v2] can: m_can: m_can_tx_handler(): fix use after free of skb Marc Kleine-Budde
2022-03-17 10:41 ` Hangyu Hua
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