diff options
author | Max <msuraev@sysmocom.de> | 2016-07-05 15:19:12 +0200 |
---|---|---|
committer | Harald Welte <laforge@gnumonks.org> | 2016-07-16 21:03:30 +0000 |
commit | 4011e728d22a9affbe41fb2bfc8e69c14bd706ab (patch) | |
tree | b0d6d66b7511cbd52a8204bb19535732e14f2d65 /openbsc/src | |
parent | 9759374adbb632ff5f8a4b739e0f62a9c9017622 (diff) |
SGSN: use unique AUTH REQ reference
The A&C reference number specified in 3GPP TS 24.008 § 10.5.5.19
identifies particular request sent by network with the related response
sent by MS. The value transparently copied from request to response by
MS: the spec do not specify what exactly should be in there so we use
rand() to decrease chance for collisions.
Note: variable named 'rand' clashes with standard function rand() so it
was renamed.
Change-Id: I3638821a9b4a0532b28dbbb50faa30c4082579f6
Related: OS#1582
Diffstat (limited to 'openbsc/src')
-rw-r--r-- | openbsc/src/gprs/gprs_gmm.c | 30 | ||||
-rw-r--r-- | openbsc/src/gprs/sgsn_main.c | 2 |
2 files changed, 24 insertions, 8 deletions
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c index 5db69ddad..7f10b0712 100644 --- a/openbsc/src/gprs/gprs_gmm.c +++ b/openbsc/src/gprs/gprs_gmm.c @@ -31,6 +31,8 @@ #include <arpa/inet.h> #include <netdb.h> +#include <openssl/rand.h> + #include <openbsc/db.h> #include <osmocom/core/msgb.h> #include <osmocom/gsm/tlv.h> @@ -417,16 +419,16 @@ static int gsm48_tx_gmm_id_req(struct sgsn_mm_ctx *mm, uint8_t id_type) } /* Section 9.4.9: Authentication and Ciphering Request */ -static int gsm48_tx_gmm_auth_ciph_req(struct sgsn_mm_ctx *mm, uint8_t *rand, +static int gsm48_tx_gmm_auth_ciph_req(struct sgsn_mm_ctx *mm, uint8_t *rnd, uint8_t key_seq, uint8_t algo) { struct msgb *msg = gsm48_msgb_alloc_name("GSM 04.08 AUTH CIPH REQ"); struct gsm48_hdr *gh; struct gsm48_auth_ciph_req *acreq; - uint8_t *m_rand, *m_cksn; + uint8_t *m_rand, *m_cksn, rbyte; LOGMMCTXP(LOGL_INFO, mm, "<- GPRS AUTH AND CIPHERING REQ (rand = %s)\n", - osmo_hexdump(rand, 16)); + osmo_hexdump(rnd, 16)); mmctx2msgid(msg, mm); @@ -438,13 +440,20 @@ static int gsm48_tx_gmm_auth_ciph_req(struct sgsn_mm_ctx *mm, uint8_t *rand, acreq->ciph_alg = algo & 0xf; acreq->imeisv_req = 0x1; acreq->force_stby = 0x0; - acreq->ac_ref_nr = 0x0; /* FIXME: increment this? */ + /* 3GPP TS 24.008 § 10.5.5.19: */ + if (RAND_bytes(&rbyte, 1) != 1) { + LOGP(DMM, LOGL_NOTICE, "RAND_bytes failed for A&C ref, falling " + "back to rand()\n"); + acreq->ac_ref_nr = rand(); + } else + acreq->ac_ref_nr = rbyte; + mm->ac_ref_nr_used = acreq->ac_ref_nr; /* Only if authentication is requested we need to set RAND + CKSN */ - if (rand) { + if (rnd) { m_rand = msgb_put(msg, 16+1); m_rand[0] = GSM48_IE_GMM_AUTH_RAND; - memcpy(m_rand+1, rand, 16); + memcpy(m_rand + 1, rnd, 16); m_cksn = msgb_put(msg, 1); m_cksn[0] = (GSM48_IE_GMM_CIPH_CKSN << 4) | (key_seq & 0x07); @@ -490,14 +499,19 @@ static int gsm48_rx_gmm_auth_ciph_resp(struct sgsn_mm_ctx *ctx, return 0; } + if (acr->ac_ref_nr != ctx->ac_ref_nr_used) { + LOGMMCTXP(LOGL_NOTICE, ctx, "Reference mismatch for Auth & Ciph" + " Response: %u received, %u expected\n", + acr->ac_ref_nr, ctx->ac_ref_nr_used); + return 0; + } + /* Stop T3360 */ mmctx_timer_stop(ctx, 3360); tlv_parse(&tp, &gsm48_gmm_att_tlvdef, acr->data, (msg->data + msg->len) - acr->data, 0, 0); - /* FIXME: compare ac_ref? */ - if (!TLVP_PRESENT(&tp, GSM48_IE_GMM_AUTH_SRES) || !TLVP_PRESENT(&tp, GSM48_IE_GMM_IMEISV)) { /* TODO: missing mandatory IE, return STATUS or REJ? */ diff --git a/openbsc/src/gprs/sgsn_main.c b/openbsc/src/gprs/sgsn_main.c index c852840db..44751363c 100644 --- a/openbsc/src/gprs/sgsn_main.c +++ b/openbsc/src/gprs/sgsn_main.c @@ -21,6 +21,7 @@ #include <unistd.h> #include <stdio.h> +#include <time.h> #include <stdlib.h> #include <string.h> #include <getopt.h> @@ -306,6 +307,7 @@ int main(int argc, char **argv) struct gsm_network dummy_network; int rc; + srand(time(NULL)); tall_bsc_ctx = talloc_named_const(NULL, 0, "osmo_sgsn"); tall_msgb_ctx = talloc_named_const(tall_bsc_ctx, 0, "msgb"); |