net: lwm2m: Make sure that endpoint string is NULL terminated

In case the endpoint string provided by the application is longer or
equal to CLIENT_EP_LEN - 1, the strncpy() function will not add the NULL
terminator. As the endpoint buffer is treated as a C-string in other
places in the code, make sure it's NULL terminated by adding NULL
explicitly at the end of the buffer.

Signed-off-by: Robert Lubos <[email protected]>

Author: rlubos

subsys/net/lib/lwm2m/lwm2m_rd_client.c

@@ -1040,6 +1040,7 @@ void lwm2m_rd_client_start(struct lwm2m_ctx *client_ctx, const char *ep_name,
 
 	set_sm_state(ENGINE_INIT);
 	strncpy(client.ep_name, ep_name, CLIENT_EP_LEN - 1);
+	client.ep_name[CLIENT_EP_LEN - 1] = '\0';
 	LOG_INF("Start LWM2M Client: %s", log_strdup(client.ep_name));
 }