From 82c9a0ec198d83452a4232f288e230b59fa1eaf8 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Mon, 13 Mar 2017 17:36:17 +0100 Subject: osmo_auth_gen_vec: UMTS auth: store last used SQN, not next Prepare for the implementation of splitting SQN increments in SEQ and an IND part; particularly to clearly show where the changes in auth/milenage_test's expectations originate. Rationale: the source of UMTS auth vectors, for us usually OsmoHLR, typically stores the last used SQN, not the next one to be used. Particularly with the upcoming fix of the SQN scheme, this change is important: the next SQN will depend on which entity asks for it, because each auth consumer may have a particular slot in the IND part of SQN. It does not make sense to store the next SQN, because we will not know which consumer that will be for. The milenage_test has always calculated a tuple for SQN == 34. To account for the increment now happening before calculating a tuple, lower the test_aud->sqn by one to 0x21 == 33, so that it is still calculating for SQN == 34. Because we are no longer incrementing SQN after the tuple is generated, milenage_test's expected output after doing an AUTS resync to 31 changes to the next SQN = 32, the SQN used for the generated tuple. (BTW, a subsequent patch will illustrate AUTS in detail.) osmo-auc-gen now needs to pass the user requested SQN less one, because the SQN will be incremented befor generating the auth vector. Also the SQN remains the same after generating, so SQN output needs less decrementing. Note that the expected output for osmo-auc-gen_test remains unchanged, hence the same input arguments (particularly -s and -A ) still produce the same results. Note: osmo-hlr regression tests will require adjustments when this patch is merged, because it must now pass desired_sqn - 1 instead of just desired_sqn. See osmo-hlr change-id I4ec5a578537acb1d9e1ebfe00a72417fc3ca5894 . Related: OS#1968 Change-Id: Iadf43f21e0605e9e85f7e8026c40985f7ceff1a3 --- src/gsm/auth_milenage.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'src/gsm/auth_milenage.c') diff --git a/src/gsm/auth_milenage.c b/src/gsm/auth_milenage.c index 1635ac6b..e1807621 100644 --- a/src/gsm/auth_milenage.c +++ b/src/gsm/auth_milenage.c @@ -30,10 +30,14 @@ static int milenage_gen_vec(struct osmo_auth_vector *vec, const uint8_t *_rand) { size_t res_len = sizeof(vec->res); + uint64_t next_sqn; uint8_t sqn[6]; int rc; - osmo_store64be_ext(aud->u.umts.sqn, sqn, 6); + /* keep the incremented SQN local until gsm_milenage() succeeded. */ + next_sqn = aud->u.umts.sqn + 1; + + osmo_store64be_ext(next_sqn, sqn, 6); milenage_generate(aud->u.umts.opc, aud->u.umts.amf, aud->u.umts.k, sqn, _rand, vec->autn, vec->ik, vec->ck, vec->res, &res_len); @@ -43,7 +47,9 @@ static int milenage_gen_vec(struct osmo_auth_vector *vec, return rc; vec->auth_types = OSMO_AUTH_TYPE_UMTS | OSMO_AUTH_TYPE_GSM; - aud->u.umts.sqn++; + + /* for storage in the caller's AUC database */ + aud->u.umts.sqn = next_sqn; return 0; } @@ -72,7 +78,7 @@ static int milenage_gen_vec_auts(struct osmo_auth_vector *vec, if (rc < 0) return rc; - aud->u.umts.sqn = 1 + (osmo_load64be_ext(sqn_out, 6) >> 16); + aud->u.umts.sqn = osmo_load64be_ext(sqn_out, 6) >> 16; return milenage_gen_vec(vec, aud, _rand); } -- cgit v1.2.3