can: add destructor for self generated skbs

Self generated skbuffs in net/can/bcm.c are setting a skb->sk reference but
no explicit destructor which is enforced since Linux 3.11 with commit
376c7311bdb6 (net: add a temporary sanity check in skb_orphan()).

This patch adds some helper functions to make sure that a destructor is
properly defined when a sock reference is assigned to a CAN related skb.
To create an unshared skb owned by the original sock a common helper function
has been introduced to replace open coded functions to create CAN echo skbs.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Andre Naujoks <nautsch2@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 4 insertions, 3 deletions

diff --git a/net/can/af_can.c b/net/can/af_can.c
index d249874a366d..a27f8aad9e99 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -57,6 +57,7 @@
 #include <linux/skbuff.h>
 #include <linux/can.h>
 #include <linux/can/core.h>
+#include <linux/can/skb.h>
 #include <linux/ratelimit.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
@@ -290,7 +291,7 @@ int can_send(struct sk_buff *skb, int loop)
                                 return -ENOMEM;
                         }
 
-                        newskb->sk = skb->sk;
+                        can_skb_set_owner(newskb, skb->sk);
                         newskb->ip_summed = CHECKSUM_UNNECESSARY;
                         newskb->pkt_type = PACKET_BROADCAST;
                 }
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 3fc737b214c7..dcb75c0e66c1 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -268,7 +268,7 @@ static void bcm_can_tx(struct bcm_op *op)
 
         /* send with loopback */
         skb->dev = dev;
-        skb->sk = op->sk;
+        can_skb_set_owner(skb, op->sk);
         can_send(skb, 1);
 
         /* update statistics */
@@ -1223,7 +1223,7 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk)
 
         can_skb_prv(skb)->ifindex = dev->ifindex;
         skb->dev = dev;
-        skb->sk  = sk;
+        can_skb_set_owner(skb, sk);
         err = can_send(skb, 1); /* send with loopback */
         dev_put(dev);