Merge tag 'linux-can-fixes-for-5.11-20210120' of...

Merge tag 'linux-can-fixes-for-5.11-20210120' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
linux-can-fixes-for-5.11-20210120

All three patches are by Vincent Mailhol and fix a potential use after free bug
in the CAN device infrastructure, the vxcan driver, and the peak_usk driver. In
the TX-path the skb is used to read from after it was passed to the networking
stack with netif_rx_ni().

* tag 'linux-can-fixes-for-5.11-20210120' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
  can: peak_usb: fix use after free bugs
  can: vxcan: vxcan_xmit: fix use after free bug
  can: dev: can_restart: fix use after free bug
====================

Link: https://lore.kernel.org/r/20210120125202.2187358-1-mkl@pengutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/can/dev.c

@@ -592,11 +592,11 @@ static void can_restart(struct net_device *dev)
 
 	cf->can_id |= CAN_ERR_RESTARTED;
 
-	netif_rx_ni(skb);
-
 	stats->rx_packets++;
 	stats->rx_bytes += cf->len;
 
+	netif_rx_ni(skb);
+
 restart:
 	netdev_dbg(dev, "restarted\n");
 	priv->can_stats.restarts++;

drivers/net/can/usb/peak_usb/pcan_usb_fd.c

@@ -514,11 +514,11 @@ static int pcan_usb_fd_decode_canmsg(struct pcan_usb_fd_if *usb_if,
 	else
 		memcpy(cfd->data, rm->d, cfd->len);
 
-	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(rm->ts_low));
-
 	netdev->stats.rx_packets++;
 	netdev->stats.rx_bytes += cfd->len;
 
+	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(rm->ts_low));
+
 	return 0;
 }
 
@@ -580,11 +580,11 @@ static int pcan_usb_fd_decode_status(struct pcan_usb_fd_if *usb_if,
 	if (!skb)
 		return -ENOMEM;
 
-	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(sm->ts_low));
-
 	netdev->stats.rx_packets++;
 	netdev->stats.rx_bytes += cf->len;
 
+	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(sm->ts_low));
+
 	return 0;
 }
 

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: