smc: ETH_ALEN as memcpy length for mac addresses

When creating an SMC connection, there is a CLC (connection layer control)
handshake to prepare for RDMA traffic. The corresponding code is part of
commit 0cfdd8f92cac ("smc: connection and link group creation").
Mac addresses to be exchanged in the handshake are copied with a wrong
length of 12 instead of 6 bytes. Following code overwrites the wrongly
copied code, but nevertheless the correct length should already be used for
the preceding mac address copying. Use ETH_ALEN for the memcpy length with
mac addresses.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Fixes: 0cfdd8f92cac ("smc: connection and link group creation")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_clc.c

@@ -10,6 +10,7 @@
  */
 
 #include <linux/in.h>
+#include <linux/if_ether.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 
@@ -151,8 +152,7 @@ int smc_clc_send_proposal(struct smc_sock *smc,
 	pclc.hdr.version = SMC_CLC_V1;		/* SMC version */
 	memcpy(pclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 	memcpy(&pclc.lcl.gid, &smcibdev->gid[ibport - 1], SMC_GID_SIZE);
-	memcpy(&pclc.lcl.mac, &smcibdev->mac[ibport - 1],
-	       sizeof(smcibdev->mac[ibport - 1]));
+	memcpy(&pclc.lcl.mac, &smcibdev->mac[ibport - 1], ETH_ALEN);
 
 	/* determine subnet and mask from internal TCP socket */
 	rc = smc_netinfo_by_tcpsk(smc->clcsock, &pclc.outgoing_subnet,
@@ -199,8 +199,7 @@ int smc_clc_send_confirm(struct smc_sock *smc)
 	memcpy(cclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 	memcpy(&cclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
 	       SMC_GID_SIZE);
-	memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
-	       sizeof(link->smcibdev->mac));
+	memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
 	hton24(cclc.qpn, link->roce_qp->qp_num);
 	cclc.rmb_rkey =
 		htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
@@ -252,8 +251,7 @@ int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
 	memcpy(aclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 	memcpy(&aclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
 	       SMC_GID_SIZE);
-	memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1],
-	       sizeof(link->smcibdev->mac[link->ibport - 1]));
+	memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
 	hton24(aclc.qpn, link->roce_qp->qp_num);
 	aclc.rmb_rkey =
 		htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);

net/smc/smc_ib.h

@@ -11,6 +11,7 @@
 #ifndef _SMC_IB_H
 #define _SMC_IB_H
 
+#include <linux/if_ether.h>
 #include <rdma/ib_verbs.h>
 
 #define SMC_MAX_PORTS			2	/* Max # of ports */
@@ -34,7 +35,8 @@ struct smc_ib_device {				/* ib-device infos for smc */
 	struct ib_cq		*roce_cq_recv;	/* recv completion queue */
 	struct tasklet_struct	send_tasklet;	/* called by send cq handler */
 	struct tasklet_struct	recv_tasklet;	/* called by recv cq handler */
-	char			mac[SMC_MAX_PORTS][6]; /* mac address per port*/
+	char			mac[SMC_MAX_PORTS][ETH_ALEN];
+						/* mac address per port*/
 	union ib_gid		gid[SMC_MAX_PORTS]; /* gid per port */
 	u8			initialized : 1; /* ib dev CQ, evthdl done */
 	struct work_struct	port_event_work;