[PATCH 5.10 107/199] can: vxcan: vxcan_xmit: fix use after free bug
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-01-26 09:45:47
Also in:
lkml
Subsystem:
can network drivers, the rest · Maintainers:
Marc Kleine-Budde, Vincent Mailhol, Linus Torvalds
From: Vincent Mailhol <redacted>
[ Upstream commit 75854cad5d80976f6ea0f0431f8cedd3bcc475cb ]
After calling netif_rx_ni(skb), dereferencing skb is unsafe.
Especially, the canfd_frame cfd which aliases skb memory is accessed
after the netif_rx_ni().
Fixes: a8f820a380a2 ("can: add Virtual CAN Tunnel driver (vxcan)")
Link: https://lore.kernel.org/r/20210120114137.200019-3-mailhol.vincent@wanadoo.fr (local)
Signed-off-by: Vincent Mailhol <redacted>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/can/vxcan.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c
index d6ba9426be4de..b1baa4ac1d537 100644
--- a/drivers/net/can/vxcan.c
+++ b/drivers/net/can/vxcan.c@@ -39,6 +39,7 @@ static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev) struct net_device *peer; struct canfd_frame *cfd = (struct canfd_frame *)skb->data; struct net_device_stats *peerstats, *srcstats = &dev->stats; + u8 len; if (can_dropped_invalid_skb(dev, skb)) return NETDEV_TX_OK;
@@ -61,12 +62,13 @@ static netdev_tx_t vxcan_xmit(struct sk_buff *skb, struct net_device *dev) skb->dev = peer; skb->ip_summed = CHECKSUM_UNNECESSARY; + len = cfd->len; if (netif_rx_ni(skb) == NET_RX_SUCCESS) { srcstats->tx_packets++; - srcstats->tx_bytes += cfd->len; + srcstats->tx_bytes += len; peerstats = &peer->stats; peerstats->rx_packets++; - peerstats->rx_bytes += cfd->len; + peerstats->rx_bytes += len; } out_unlock:
--
2.27.0