nat: Use memcmp for the token on the USSD interface as well
This is similar to the token on the A-interface. There are no more
token based authentication in the NAT.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_ussd.c b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
index f6dbef2..f972ba5 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_ussd.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_ussd.c
@@ -159,12 +159,13 @@
token = (const char *) TLVP_VAL(tvp, IPAC_IDTAG_UNITNAME);
len = TLVP_LEN(tvp, IPAC_IDTAG_UNITNAME);
- if (strncmp(conn->nat->ussd_token, token, len) != 0) {
- LOGP(DNAT, LOGL_ERROR, "Wrong USSD token by client: %d\n",
- conn->queue.bfd.fd);
- bsc_nat_ussd_destroy(conn);
- return;
- }
+
+ /* last byte should be a NULL */
+ if (strlen(conn->nat->ussd_token) != len - 1)
+ goto disconnect;
+ /* compare everything including the null byte */
+ if (memcmp(conn->nat->ussd_token, token, len) != 0)
+ goto disconnect;
/* it is authenticated now */
if (conn->nat->ussd_con && conn->nat->ussd_con != conn)
@@ -174,6 +175,12 @@
osmo_timer_del(&conn->auth_timeout);
conn->authorized = 1;
conn->nat->ussd_con = conn;
+ return;
+
+disconnect:
+ LOGP(DNAT, LOGL_ERROR, "Wrong USSD token by client: %d\n",
+ conn->queue.bfd.fd);
+ bsc_nat_ussd_destroy(conn);
}
static void ussd_start_auth(struct bsc_nat_ussd_con *conn)