can: dev: fix skb drop check

In commit a6d190f8c7 ("can: skb: drop tx skb if in listen only
mode") the priv->ctrlmode element is read even on virtual CAN
interfaces that do not create the struct can_priv at startup. This
out-of-bounds read may lead to CAN frame drops for virtual CAN
interfaces like vcan and vxcan.

This patch mainly reverts the original commit and adds a new helper
for CAN interface drivers that provide the required information in
struct can_priv.

Fixes: a6d190f8c7 ("can: skb: drop tx skb if in listen only mode")
Reported-by: Dariusz Stojaczyk <Dariusz.Stojaczyk@opensynergy.com>
Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Cc: Max Staudt <max@enpas.org>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20221102095431.36831-1-socketcan@hartkopp.net
Cc: stable@vger.kernel.org # 6.0.x
[mkl: patch pch_can, too]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/at91_can.c

@@ -452,7 +452,7 @@ static netdev_tx_t at91_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	unsigned int mb, prio;
 	u32 reg_mid, reg_mcr;
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	mb = get_tx_next_mb(priv);

drivers/net/can/c_can/c_can_main.c

@@ -457,7 +457,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
 	struct c_can_tx_ring *tx_ring = &priv->tx;
 	u32 idx, obj, cmd = IF_COMM_TX;
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	if (c_can_tx_busy(priv, tx_ring))

drivers/net/can/can327.c

@@ -813,7 +813,7 @@ static netdev_tx_t can327_netdev_start_xmit(struct sk_buff *skb,
 	struct can327 *elm = netdev_priv(dev);
 	struct can_frame *frame = (struct can_frame *)skb->data;
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	/* We shouldn't get here after a hardware fault:

drivers/net/can/cc770/cc770.c

@@ -429,7 +429,7 @@ static netdev_tx_t cc770_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct cc770_priv *priv = netdev_priv(dev);
 	unsigned int mo = obj2msgobj(CC770_OBJ_TX);
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	netif_stop_queue(dev);

drivers/net/can/ctucanfd/ctucanfd_base.c

@@ -600,7 +600,7 @@ static netdev_tx_t ctucan_start_xmit(struct sk_buff *skb, struct net_device *nde
 	bool ok;
 	unsigned long flags;
 
-	if (can_dropped_invalid_skb(ndev, skb))
+	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
 	if (unlikely(!CTU_CAN_FD_TXTNF(priv))) {

drivers/net/can/dev/skb.c

@@ -5,7 +5,6 @@
  */
 
 #include <linux/can/dev.h>
-#include <linux/can/netlink.h>
 #include <linux/module.h>
 
 #define MOD_DESC "CAN device driver interface"
@@ -337,8 +336,6 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb)
 /* Drop a given socketbuffer if it does not contain a valid CAN frame. */
 bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)
 {
-	struct can_priv *priv = netdev_priv(dev);
-
 	switch (ntohs(skb->protocol)) {
 	case ETH_P_CAN:
 		if (!can_is_can_skb(skb))
@@ -359,13 +356,8 @@ bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)
 		goto inval_skb;
 	}
 
-	if (!can_skb_headroom_valid(dev, skb)) {
+	if (!can_skb_headroom_valid(dev, skb))
 		goto inval_skb;
-	} else if (priv->ctrlmode & CAN_CTRLMODE_LISTENONLY) {
-		netdev_info_once(dev,
-				 "interface in listen only mode, dropping skb\n");
-		goto inval_skb;
-	}
 
 	return false;
 

drivers/net/can/flexcan/flexcan-core.c

@@ -742,7 +742,7 @@ static netdev_tx_t flexcan_start_xmit(struct sk_buff *skb, struct net_device *de
 	u32 ctrl = FLEXCAN_MB_CODE_TX_DATA | ((can_fd_len2dlc(cfd->len)) << 16);
 	int i;
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	netif_stop_queue(dev);

drivers/net/can/grcan.c

@@ -1345,7 +1345,7 @@ static netdev_tx_t grcan_start_xmit(struct sk_buff *skb,
 	unsigned long flags;
 	u32 oneshotmode = priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT;
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	/* Trying to transmit in silent mode will generate error interrupts, but

drivers/net/can/ifi_canfd/ifi_canfd.c

@@ -860,7 +860,7 @@ static netdev_tx_t ifi_canfd_start_xmit(struct sk_buff *skb,
 	u32 txst, txid, txdlc;
 	int i;
 
-	if (can_dropped_invalid_skb(ndev, skb))
+	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
 	/* Check if the TX buffer is full */

drivers/net/can/janz-ican3.c

@@ -1693,7 +1693,7 @@ static netdev_tx_t ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
 	void __iomem *desc_addr;
 	unsigned long flags;
 
-	if (can_dropped_invalid_skb(ndev, skb))
+	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
 	spin_lock_irqsave(&mod->lock, flags);

drivers/net/can/kvaser_pciefd.c

@@ -772,7 +772,7 @@ static netdev_tx_t kvaser_pciefd_start_xmit(struct sk_buff *skb,
 	int nwords;
 	u8 count;
 
-	if (can_dropped_invalid_skb(netdev, skb))
+	if (can_dev_dropped_skb(netdev, skb))
 		return NETDEV_TX_OK;
 
 	nwords = kvaser_pciefd_prepare_tx_packet(&packet, can, skb);

drivers/net/can/m_can/m_can.c

@@ -1721,7 +1721,7 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
 {
 	struct m_can_classdev *cdev = netdev_priv(dev);
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	if (cdev->is_peripheral) {

drivers/net/can/mscan/mscan.c

@@ -191,7 +191,7 @@ static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	int i, rtr, buf_id;
 	u32 can_id;
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	out_8(&regs->cantier, 0);

drivers/net/can/pch_can.c

@@ -882,7 +882,7 @@ static netdev_tx_t pch_xmit(struct sk_buff *skb, struct net_device *ndev)
 	int i;
 	u32 id2;
 
-	if (can_dropped_invalid_skb(ndev, skb))
+	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
 	tx_obj_no = priv->tx_obj;

drivers/net/can/peak_canfd/peak_canfd.c

@@ -651,7 +651,7 @@ static netdev_tx_t peak_canfd_start_xmit(struct sk_buff *skb,
 	int room_left;
 	u8 len;
 
-	if (can_dropped_invalid_skb(ndev, skb))
+	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
 	msg_size = ALIGN(sizeof(*msg) + cf->len, 4);

drivers/net/can/rcar/rcar_can.c

@@ -590,7 +590,7 @@ static netdev_tx_t rcar_can_start_xmit(struct sk_buff *skb,
 	struct can_frame *cf = (struct can_frame *)skb->data;
 	u32 data, i;
 
-	if (can_dropped_invalid_skb(ndev, skb))
+	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
 	if (cf->can_id & CAN_EFF_FLAG)	/* Extended frame format */

drivers/net/can/rcar/rcar_canfd.c

@@ -1481,7 +1481,7 @@ static netdev_tx_t rcar_canfd_start_xmit(struct sk_buff *skb,
 	unsigned long flags;
 	u32 ch = priv->channel;
 
-	if (can_dropped_invalid_skb(ndev, skb))
+	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
 	if (cf->can_id & CAN_EFF_FLAG) {

drivers/net/can/sja1000/sja1000.c

@@ -291,7 +291,7 @@ static netdev_tx_t sja1000_start_xmit(struct sk_buff *skb,
 	u8 cmd_reg_val = 0x00;
 	int i;
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	netif_stop_queue(dev);

drivers/net/can/slcan/slcan-core.c

@@ -594,7 +594,7 @@ static netdev_tx_t slcan_netdev_xmit(struct sk_buff *skb,
 {
 	struct slcan *sl = netdev_priv(dev);
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	spin_lock(&sl->lock);

drivers/net/can/softing/softing_main.c

@@ -60,7 +60,7 @@ static netdev_tx_t softing_netdev_start_xmit(struct sk_buff *skb,
 	struct can_frame *cf = (struct can_frame *)skb->data;
 	uint8_t buf[DPRAM_TX_SIZE];
 
-	if (can_dropped_invalid_skb(dev, skb))
+	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
 
 	spin_lock(&card->spin);