diff options
| author | Anssi Hannula <anssi.hannula@bitwise.fi> | 2025-08-22 12:50:02 +0300 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2025-09-10 17:12:05 +0200 |
| commit | ef79f00be72bd81d2e1e6f060d83cf7e425deee4 (patch) | |
| tree | bee29abea0cf676381551e89cbbd263c0cf3f821 | |
| parent | 06e02da29f6f1a45fc07bd60c7eaf172dc21e334 (diff) | |
can: xilinx_can: xcan_write_frame(): fix use-after-free of transmitted SKB
can_put_echo_skb() takes ownership of the SKB and it may be freed
during or after the call.
However, xilinx_can xcan_write_frame() keeps using SKB after the call.
Fix that by only calling can_put_echo_skb() after the code is done
touching the SKB.
The tx_lock is held for the entire xcan_write_frame() execution and
also on the can_get_echo_skb() side so the order of operations does not
matter.
An earlier fix commit 3d3c817c3a40 ("can: xilinx_can: Fix usage of skb
memory") did not move the can_put_echo_skb() call far enough.
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Fixes: 1598efe57b3e ("can: xilinx_can: refactor code in preparation for CAN FD support")
Link: https://patch.msgid.link/20250822095002.168389-1-anssi.hannula@bitwise.fi
[mkl: add "commit" in front of sha1 in patch description]
[mkl: fix indention]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
| -rw-r--r-- | drivers/net/can/xilinx_can.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index 81baec8eb1e5..a25a3ca62c12 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -690,14 +690,6 @@ static void xcan_write_frame(struct net_device *ndev, struct sk_buff *skb, dlc |= XCAN_DLCR_EDL_MASK; } - if (!(priv->devtype.flags & XCAN_FLAG_TX_MAILBOXES) && - (priv->devtype.flags & XCAN_FLAG_TXFEMP)) - can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max, 0); - else - can_put_echo_skb(skb, ndev, 0, 0); - - priv->tx_head++; - priv->write_reg(priv, XCAN_FRAME_ID_OFFSET(frame_offset), id); /* If the CAN frame is RTR frame this write triggers transmission * (not on CAN FD) @@ -730,6 +722,14 @@ static void xcan_write_frame(struct net_device *ndev, struct sk_buff *skb, data[1]); } } + + if (!(priv->devtype.flags & XCAN_FLAG_TX_MAILBOXES) && + (priv->devtype.flags & XCAN_FLAG_TXFEMP)) + can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max, 0); + else + can_put_echo_skb(skb, ndev, 0, 0); + + priv->tx_head++; } /** |