net: lwm2m_client_utils: Don't return unknown FOTA errors

We should take care to not return any other error than
what lwm2m_obj_firmware.c handles. If we for example return
-EACCESS, then LwM2M content format writer ignores that as
it is supposed to skip over write requests to read-only
resources. So we now default to -EFAULT, so we don't
cause any undefined behaviour.

Signed-off-by: Seppo Takalo <[email protected]>

Author: SeppoTakalo

subsys/net/lib/lwm2m_client_utils/lwm2m/lwm2m_firmware.c

@@ -845,6 +845,24 @@ static int firmware_block_received_cb(uint16_t obj_inst_id, uint16_t res_id, uin
 		if (dfu_target_reset() < 0) {
 			LOG_ERR("Failed to reset DFU target");
 		}
+		/* We must return only known values for LwM2M firmware handler. */
+		switch (ret) {
+		case -ENOMEM:
+		case -ENOSPC:
+		case -EFAULT:
+		case -ENOMSG:
+			break;
+		case -EFBIG:
+		case -E2BIG:
+			ret = -ENOSPC;
+			break;
+		case -EINVAL:
+			ret = -ENOMSG;
+			break;
+		default:
+			ret = -EFAULT;
+			break;
+		}
 	}
 
 	return ret;