nfs: Avoid overrun when copying client IP address string

As seen in <http://bugs.debian.org/549002>, nfs4_init_client() can
overrun the source string when copying the client IP address from
nfs_parsed_mount_data::client_address to nfs_client::cl_ipaddr.  Since
these are both treated as null-terminated strings elsewhere, the copy
should be done with strlcpy() not memcpy().
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/client.c

@@ -1180,7 +1180,7 @@ static int nfs4_init_client(struct nfs_client *clp,
 				      1, flags & NFS_MOUNT_NORESVPORT);
 	if (error < 0)
 		goto error;
-	memcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
+	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
 
 	error = nfs_idmap_new(clp);
 	if (error < 0) {