SGSN / GMM: Only allow non-roaming IMSIs
As we do not yet use the HLR from the SGSN, we allow all MS to
attach to our GPRS network. However, if this is running in a public
environment, it could cause service interruption to users of commercial
GPRS networks.
Thus, we now check if the first 5 digits of the IMSI match the MCC/MNC
of the cell that they want to register to. Thus, any subscribers with
SIM cards from real operators will no longer be accepted.
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index 82a4ca8..158f577 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -671,7 +671,16 @@
#if 0
return gsm48_tx_gmm_att_rej(msg, GMM_CAUSE_IMSI_UNKNOWN);
#else
- /* As a temorary hack, we simply assume that the IMSI exists */
+ /* As a temorary hack, we simply assume that the IMSI exists,
+ * as long as it is part of 'our' network */
+ char mccmnc[16];
+ snprintf(mccmnc, sizeof(mccmnc), "%03d%02d", ra_id.mcc, ra_id.mnc);
+ if (strncmp(mccmnc, mi_string, 5)) {
+ LOGP(DMM, LOGL_INFO, "Rejecting ATTACH REQUESET IMSI=%s\n",
+ mi_string);
+ return gsm48_tx_gmm_att_rej_oldmsg(msg,
+ GMM_CAUSE_GPRS_NOTALLOWED);
+ }
ctx = sgsn_mm_ctx_alloc(0, &ra_id);
if (!ctx)
return gsm48_tx_gmm_att_rej_oldmsg(msg, GMM_CAUSE_NET_FAIL);