From f43e64076ff1b1dcb893fb77ad1204105f710a29 Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Thu, 17 Mar 2022 08:57:35 +0100 Subject: [PATCH] can: m_can: m_can_tx_handler(): fix use after free of skb commit 2e8e79c416aae1de224c0f1860f2e3350fa171f8 upstream. 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 Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- 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 25713d623215..bff33a619acd 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1640,8 +1640,6 @@ 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; @@ -1658,6 +1656,9 @@ 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 {