Commit 7728d937 authored Mar 17, 2022 by Marc Kleine-Budde Committed by Greg Kroah-Hartman Jul 21, 2022

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: 80646733 ("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>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent c44117bf

drivers/net/can/m_can/m_can.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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 {