can: introduce CAN_REQUIRED_SIZE macro

The size of this structure will be increased with J1939 support. To stay binary compatible, the CAN_REQUIRED_SIZE macro is introduced for existing CAN protocols. Signed-off-by: Kurt Van Dijck <[email protected]> Signed-off-by: Oleksij Rempel <[email protected]> Acked-by: Oliver Hartkopp <[email protected]> Signed-off-by: Marc Kleine-Budde <[email protected]>
Netflix-Skunkworks · Sep 4, 2019 · 9868b5d · 9868b5d
1 parent 4f746fb
commit 9868b5d
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Showing 3 changed files with 12 additions and 4 deletions.
diff --git a/include/linux/can/core.h b/include/linux/can/core.h
@@ -41,6 +41,14 @@ struct can_proto {
 	struct proto *prot;
 };
 
+/* required_size
+ * macro to find the minimum size of a struct
+ * that includes a requested member
+ */
+#define CAN_REQUIRED_SIZE(struct_type, member) \
+	(offsetof(typeof(struct_type), member) + \
+	 sizeof(((typeof(struct_type) *)(NULL))->member))
+
 /* function prototypes for the CAN networklayer core (af_can.c) */
 
 extern int  can_proto_register(const struct can_proto *cp);

diff --git a/net/can/bcm.c b/net/can/bcm.c
@@ -1294,7 +1294,7 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 		/* no bound device as default => check msg_name */
 		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
 
-		if (msg->msg_namelen < sizeof(*addr))
+		if (msg->msg_namelen < CAN_REQUIRED_SIZE(*addr, can_ifindex))
 			return -EINVAL;
 
 		if (addr->can_family != AF_CAN)
@@ -1536,7 +1536,7 @@ static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
 	struct net *net = sock_net(sk);
 	int ret = 0;
 
-	if (len < sizeof(*addr))
+	if (len < CAN_REQUIRED_SIZE(*addr, can_ifindex))
 		return -EINVAL;
 
 	lock_sock(sk);

diff --git a/net/can/raw.c b/net/can/raw.c
@@ -396,7 +396,7 @@ static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
 	int err = 0;
 	int notify_enetdown = 0;
 
-	if (len < sizeof(*addr))
+	if (len < CAN_REQUIRED_SIZE(*addr, can_ifindex))
 		return -EINVAL;
 	if (addr->can_family != AF_CAN)
 		return -EINVAL;
@@ -733,7 +733,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	if (msg->msg_name) {
 		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
 
-		if (msg->msg_namelen < sizeof(*addr))
+		if (msg->msg_namelen < CAN_REQUIRED_SIZE(*addr, can_ifindex))
 			return -EINVAL;
 
 		if (addr->can_family != AF_CAN)