sgsn: Add a subscriber based authentication phase
This implements the MAP way of subscriber validation when the MS
tries to perform an Attach Request:
1. perform authentication (optionally invoke the sendAuthInfo
procedure), starts the Auth & Ciph procedure
2. perform update location
3. insert subscriber data
4. finish the update location
5. Attach Accept / Attach Reject
The authentication triplets are used and eventually updated if all of
them have been used.
This is currently accessible via the VTY interface by the following
commands:
- update-subscriber imsi IMSI update-auth-info
- update-subscriber imsi IMSI update-location-result (ok|ERR-CAUSE)
Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/gprs/sgsn_auth.c b/openbsc/src/gprs/sgsn_auth.c
index b065c06..3755a51 100644
--- a/openbsc/src/gprs/sgsn_auth.c
+++ b/openbsc/src/gprs/sgsn_auth.c
@@ -23,7 +23,7 @@
#include <openbsc/gprs_sgsn.h>
#include <openbsc/gprs_gmm.h>
#include <openbsc/gsm_subscriber.h>
-
+#include <openbsc/gsm_04_08_gprs.h>
#include <openbsc/debug.h>
const struct value_string auth_state_names[] = {
@@ -107,11 +107,12 @@
if (!mmctx->subscr)
return mmctx->auth_state;
- if (mmctx->subscr->flags & GPRS_SUBSCRIBER_UPDATE_PENDING)
+ if (mmctx->subscr->flags & GPRS_SUBSCRIBER_UPDATE_PENDING_MASK)
return mmctx->auth_state;
if (mmctx->subscr->sgsn_data->authenticate &&
- !mmctx->is_authenticated)
+ (!mmctx->is_authenticated ||
+ mmctx->subscr->sgsn_data->auth_triplets_updated))
return SGSN_AUTH_AUTHENTICATE;
if (mmctx->subscr->authorized)
@@ -141,20 +142,60 @@
return SGSN_AUTH_REJECTED;
}
+/*
+ * This function is directly called by e.g. the GMM layer. It returns either
+ * after calling sgsn_auth_update directly or after triggering an asynchronous
+ * procedure which will call sgsn_auth_update later on.
+ */
int sgsn_auth_request(struct sgsn_mm_ctx *mmctx)
{
+ struct gsm_subscriber *subscr;
+ struct gsm_auth_tuple *at;
+ int need_update_location;
+ int rc;
+
LOGMMCTXP(LOGL_DEBUG, mmctx, "Requesting authorization\n");
- if (sgsn->cfg.auth_policy == SGSN_AUTH_POLICY_REMOTE && !mmctx->subscr) {
- if (gprs_subscr_request_update(mmctx) >= 0) {
+ if (sgsn->cfg.auth_policy != SGSN_AUTH_POLICY_REMOTE) {
+ sgsn_auth_update(mmctx);
+ return 0;
+ }
+
+ need_update_location =
+ mmctx->subscr == NULL ||
+ mmctx->pending_req == GSM48_MT_GMM_ATTACH_REQ;
+
+ /* This has the side effect of registering the subscr with the mmctx */
+ subscr = gprs_subscr_get_or_create_by_mmctx(mmctx);
+ subscr_put(subscr);
+
+ OSMO_ASSERT(mmctx->subscr != NULL);
+
+ if (mmctx->subscr->sgsn_data->authenticate && !mmctx->is_authenticated) {
+ /* Find next tuple */
+ at = sgsn_auth_get_tuple(mmctx, mmctx->auth_triplet.key_seq);
+
+ if (!at) {
+ /* No valid tuple found, request fresh ones */
+ mmctx->auth_triplet.key_seq = GSM_KEY_SEQ_INVAL;
LOGMMCTXP(LOGL_INFO, mmctx,
- "Missing information, requesting subscriber data\n");
- return 0;
+ "Requesting authentication tuples\n");
+ rc = gprs_subscr_request_auth_info(mmctx);
+ if (rc >= 0)
+ return 0;
+
+ return rc;
}
+
+ mmctx->auth_triplet = *at;
+ } else if (need_update_location) {
+ LOGMMCTXP(LOGL_INFO, mmctx,
+ "Missing information, requesting subscriber data\n");
+ if (gprs_subscr_request_update_location(mmctx) >= 0)
+ return 0;
}
sgsn_auth_update(mmctx);
-
return 0;
}
@@ -162,6 +203,7 @@
{
enum sgsn_auth_state auth_state;
struct gsm_subscriber *subscr = mmctx->subscr;
+ struct gsm_auth_tuple *at;
auth_state = sgsn_auth_state(mmctx);
@@ -170,13 +212,27 @@
get_value_string(sgsn_auth_state_names, auth_state));
if (auth_state == SGSN_AUTH_UNKNOWN && subscr &&
- !(subscr->flags & GPRS_SUBSCRIBER_UPDATE_PENDING)) {
- /* Reject requests if gprs_subscr_request_update fails */
+ !(subscr->flags & GPRS_SUBSCRIBER_UPDATE_PENDING_MASK)) {
+ /* Reject requests if gprs_subscr_request_update_location fails */
LOGMMCTXP(LOGL_ERROR, mmctx,
"Missing information, authorization not possible\n");
auth_state = SGSN_AUTH_REJECTED;
}
+ if (auth_state == SGSN_AUTH_AUTHENTICATE &&
+ mmctx->auth_triplet.key_seq == GSM_KEY_SEQ_INVAL) {
+ /* The current tuple is not valid, but we are possibly called
+ * because new auth tuples have been received */
+ at = sgsn_auth_get_tuple(mmctx, mmctx->auth_triplet.key_seq);
+ if (!at) {
+ LOGMMCTXP(LOGL_ERROR, mmctx,
+ "Missing auth tuples, authorization not possible\n");
+ auth_state = SGSN_AUTH_REJECTED;
+ } else {
+ mmctx->auth_triplet = *at;
+ }
+ }
+
if (mmctx->auth_state == auth_state)
return;
@@ -188,6 +244,9 @@
switch (auth_state) {
case SGSN_AUTH_AUTHENTICATE:
+ if (subscr)
+ subscr->sgsn_data->auth_triplets_updated = 0;
+
gsm0408_gprs_authenticate(mmctx);
break;
case SGSN_AUTH_ACCEPTED: