[PATCH] can: raw: fix TX CAN frames show up as RX'ed ones

[Marc Kleine-Budde <mkl@pengutronix.de>]

Fixes: e940e0895a82 ("can: skb: can_skb_set_owner(): fix ref counting if socket was closed before setting skb ownership")
Reported-by: Torin Cooper-Bennun <torin@maxiluxsystems.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
Hey Torin,

this is only compile time tested. Please give it a try.

regards,
Marc

 drivers/net/can/dev/skb.c |  2 ++
 include/linux/can/skb.h   | 14 +++++++++++---
 net/can/raw.c             |  2 +-
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c
index 61660248c69e..9644c0d85bb6 100644
--- a/drivers/net/can/dev/skb.c
+++ b/drivers/net/can/dev/skb.c
@@ -200,6 +200,7 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 	can_skb_reserve(skb);
 	can_skb_prv(skb)->ifindex = dev->ifindex;
 	can_skb_prv(skb)->skbcnt = 0;
+	can_skb_prv(skb)->flags = 0;
 
 	*cf = skb_put_zero(skb, sizeof(struct can_frame));
 
@@ -231,6 +232,7 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 	can_skb_reserve(skb);
 	can_skb_prv(skb)->ifindex = dev->ifindex;
 	can_skb_prv(skb)->skbcnt = 0;
+	can_skb_prv(skb)->flags = 0;
 
 	*cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 
diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
index d311bc369a39..24a3e682b4a2 100644
--- a/include/linux/can/skb.h
+++ b/include/linux/can/skb.h
@@ -51,6 +51,7 @@ struct can_skb_priv {
 	int ifindex;
 	int skbcnt;
 	unsigned int frame_len;
+	unsigned int flags;
 	struct can_frame cf[];
 };
 
@@ -71,9 +72,16 @@ static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
 	 * after the last TX skb has been freed). So only increase
 	 * socket refcount if the refcount is > 0.
 	 */
-	if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) {
-		skb->destructor = sock_efree;
-		skb->sk = sk;
+	if (sk) {
+		struct can_skb_priv *skb_priv;
+
+		skb_priv = can_skb_prv(skb);
+		skb_priv->flags = MSG_DONTROUTE;
+
+		if (refcount_inc_not_zero(&sk->sk_refcnt)) {
+			skb->destructor = sock_efree;
+			skb->sk = sk;
+		}
 	}
 }
 
diff --git a/net/can/raw.c b/net/can/raw.c
index 139d9471ddcf..9bedd0672fae 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -169,7 +169,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
 	/* add CAN specific message flags for raw_recvmsg() */
 	pflags = raw_flags(skb);
 	*pflags = 0;
-	if (oskb->sk)
+	if (can_skb_prv(oskb)->flags == MSG_DONTROUTE)
 		*pflags |= MSG_DONTROUTE;
 	if (oskb->sk == sk)
 		*pflags |= MSG_CONFIRM;
-- 
2.30.2