diff --git a/openbsc/src/libcommon/gsm_subscriber_base.c b/openbsc/src/libcommon/gsm_subscriber_base.c
index 3c56101..a455824 100644
--- a/openbsc/src/libcommon/gsm_subscriber_base.c
+++ b/openbsc/src/libcommon/gsm_subscriber_base.c
@@ -112,8 +112,7 @@
 	if (!subscr)
 		return NULL;
 
-	strncpy(subscr->imsi, imsi, GSM_IMSI_LENGTH);
-	subscr->imsi[GSM_IMSI_LENGTH - 1] = '\0';
+	strncpy(subscr->imsi, imsi, GSM_IMSI_LENGTH-1);
 	subscr->group = sgrp;
 	return subscr;
 }
diff --git a/openbsc/src/libmsc/db.c b/openbsc/src/libmsc/db.c
index bdecbb4..428f99b 100644
--- a/openbsc/src/libmsc/db.c
+++ b/openbsc/src/libmsc/db.c
@@ -565,7 +565,7 @@
 
 	string = dbi_result_get_string(result, "imei");
 	if (string)
-		strncpy(equip->imei, string, sizeof(equip->imei));
+		strncpy(equip->imei, string, sizeof(equip->imei)-1);
 
 	string = dbi_result_get_string(result, "classmark1");
 	if (string) {
@@ -802,7 +802,7 @@
 	const char *string;
 	string = dbi_result_get_string(result, "imsi");
 	if (string)
-		strncpy(subscr->imsi, string, GSM_IMSI_LENGTH);
+		strncpy(subscr->imsi, string, GSM_IMSI_LENGTH-1);
 
 	string = dbi_result_get_string(result, "tmsi");
 	if (string)
diff --git a/openbsc/src/osmo-bsc_nat/bsc_ussd.c b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
index ac5a9f5..67844b8 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_ussd.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
@@ -399,7 +399,7 @@
 	if (parsed->bssap != BSSAP_MSG_DTAP)
 		return 0;
 
-	if (strlen(con->imsi) > GSM_IMSI_LENGTH)
+	if (strlen(con->imsi) >= GSM_IMSI_LENGTH)
 		return 0;
 
 	hdr48 = bsc_unpack_dtap(parsed, msg, &len);