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sgsn: Move IMSI authorization to gsm48_gmm_authorize 

Currently the IMSI is only checked immediately when an Attach Request
is received that contains an IMSI IE. If it contains a P-TMSI
instead, access is always granted.

This commit moves the IMSI check to gsm48_gmm_authorize where it is
applied when IMSI and IMEI have been acquired. This fixes the
authorization when the Attach Accept doesn't contain an IMSI.

Sponsored-by: On-Waves ehf
This commit is contained in:
Jacob Erlbeck 2014-10-29 22:12:20 +01:00 committed by Holger Hans Peter Freyther
parent b1c074f62c
commit 0c06f98ced
3 changed files with 28 additions and 16 deletions
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2
openbsc/include/openbsc/gprs_sgsn.h
View File

@ -117,6 +117,8 @@ struct sgsn_mm_ctx {
* (refers to the timer) and pending_req (refers to the procedure),
* where mm->T == 3350 => mm->t3350_mode == f(mm->pending_req). Check
* whether one of them can be dropped. */
int is_authorized;
};
#define LOGMMCTXP(level, mm, fmt, args...) \

35
openbsc/src/gprs/gprs_gmm.c
View File

@ -640,9 +640,30 @@ static int gsm48_gmm_authorize(struct sgsn_mm_ctx *ctx)
}
/* All information required for authentication is available */
ctx->t3370_id_type = GSM_MI_TYPE_NONE;
if (!ctx->is_authorized) {
/* As a temorary hack, we simply assume that the IMSI exists,
* as long as it is part of 'our' network */
char mccmnc[16];
int rc;
snprintf(mccmnc, sizeof(mccmnc), "%03d%02d",
ctx->ra.mcc, ctx->ra.mnc);
if (strncmp(mccmnc, ctx->imsi, 5) &&
(sgsn->cfg.acl_enabled &&
!sgsn_acl_lookup(ctx->imsi, &sgsn->cfg))) {
LOGP(DMM, LOGL_NOTICE, "Rejecting ATTACH REQUEST IMSI=%s\n",
ctx->imsi);
rc = gsm48_tx_gmm_att_rej(ctx,
GMM_CAUSE_GPRS_NOTALLOWED);
mm_ctx_cleanup_free(ctx, "ATTACH REJECT");
return rc;
}
ctx->is_authorized = 1;
}
/* The MS is authorized */
switch (ctx->pending_req) {
case 0:
LOGMMCTXP(LOGL_INFO, ctx,
@ -799,18 +820,6 @@ static int gsm48_rx_gmm_att_req(struct sgsn_mm_ctx *ctx, struct msgb *msg,
#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 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) &&
(sgsn->cfg.acl_enabled &&
!sgsn_acl_lookup(mi_string, &sgsn->cfg))) {
LOGP(DMM, LOGL_NOTICE, "Rejecting ATTACH REQUEST 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);

7
openbsc/tests/sgsn/sgsn_test.c
View File

@ -340,6 +340,8 @@ static void test_gmm_attach(void)
/* reset the PRNG used by sgsn_alloc_ptmsi */
srand(1);
sgsn_acl_add("123456789012345", &sgsn->cfg);
foreign_tlli = gprs_tmsi2tlli(0xc0000023, TLLI_FOREIGN);
/* Create a LLE/LLME */
@ -369,9 +371,6 @@ static void test_gmm_attach(void)
send_0408_message(ctx->llme, foreign_tlli,
ident_resp_imsi, ARRAY_SIZE(ident_resp_imsi));
/* FIXME: We are not authorized and should get an Attach Reject, fix
* authorization in gprs_gmm.c */
/* check that the MM context has not been removed due to a failed
* authorization */
OSMO_ASSERT(ctx == sgsn_mm_ctx_by_tlli(foreign_tlli, &raid));
@ -401,6 +400,8 @@ static void test_gmm_attach(void)
OSMO_ASSERT(count(gprs_llme_list()) == 0);
ictx = sgsn_mm_ctx_by_tlli(local_tlli, &raid);
OSMO_ASSERT(!ictx);
sgsn_acl_del("123456789012345", &sgsn->cfg);
}
static struct log_info_cat gprs_categories[] = {