From: Marc Kleine-Budde Date: Thu, 17 Mar 2022 07:57:35 +0000 (+0100) Subject: can: m_can: m_can_tx_handler(): fix use after free of skb X-Git-Tag: v4.19.253~1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7728d937ec403a1ceff9483023252d2cb8777f81;p=thirdparty%2Fkernel%2Fstable.git 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 [sudip: adjust context] Signed-off-by: Sudip Mukherjee Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index f5f1367d40d5c..4b88fabbdcbaa 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1438,8 +1438,6 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb, M_CAN_FIFO_DATA(i / 4), *(u32 *)(cf->data + i)); - can_put_echo_skb(skb, dev, 0); - if (priv->can.ctrlmode & CAN_CTRLMODE_FD) { cccr = m_can_read(priv, M_CAN_CCCR); cccr &= ~(CCCR_CMR_MASK << CCCR_CMR_SHIFT); @@ -1456,6 +1454,9 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb, m_can_write(priv, M_CAN_CCCR, cccr); } m_can_write(priv, M_CAN_TXBTIE, 0x1); + + can_put_echo_skb(skb, dev, 0); + m_can_write(priv, M_CAN_TXBAR, 0x1); /* End of xmit function for version 3.0.x */ } else {