diff options
authorNeels Hofmeyr <neels@hofmeyr.de>2017-12-18 01:23:42 +0100
committerNeels Hofmeyr <neels@hofmeyr.de>2017-12-18 05:18:11 +0100
commit2ef2da54abd537cc131aa9815a0d1bb91d0987e0 (patch)
parente3d72d782799700a0544b4fdd7b0bcb3d4a210cd (diff)
cosmetic prep: tell vlr_ops.set_ciph_mode() whether UMTS AKA is used
In case of UMTS AKA, the Kc for ciphering must be derived from the 3G auth tokens. tuple->vec.kc was calculated from the GSM algorithm and is not necessarily a match for the UMTS AKA tokens. To decide (in an upcoming patch) whether to use UMTS AKA derived Kc or the Kc from the auth vector, the set_ciph_mode() from vlr_ops needs to know whether UMTS AKA is being used. This could possibly derived from the msc_conn_ref, but all flags are already available in the vlr_lu_fsm and vlr_access_req_fsm. Hence add a umts_aka flag to the set_ciph_mode() callback invocation. The VLR FSMs thus decide whether UMTS AKA or GSM AKA is to be used during Ciphering Mode Command, which makes more sense than re-implementing the same decision process in the MSC. I considered placing the Kc derivation in vlr_set_ciph_mode() and only tell the MSC's set_ciph_mode() implementation the precise keys it should use, but the RAN particulars, and whether a Kc is used at all, rather belong with the MSC. Related: OS#2745 Prepares: If04e405426c55a81341747a9b450a69188525d5c Change-Id: I983c48347faf4ee1b405d8174b4e006c904157cf
6 files changed, 14 insertions, 2 deletions
diff --git a/include/osmocom/msc/vlr.h b/include/osmocom/msc/vlr.h
index df7d3548b..b6256086c 100644
--- a/include/osmocom/msc/vlr.h
+++ b/include/osmocom/msc/vlr.h
@@ -207,7 +207,7 @@ struct vlr_ops {
int (*tx_cm_serv_rej)(void *msc_conn_ref, enum vlr_proc_arq_result result);
int (*set_ciph_mode)(void *msc_conn_ref, enum vlr_ciph ciph_mode,
- bool retrieve_imeisv);
+ bool umts_aka, bool retrieve_imeisv);
/* UTRAN: send Common Id (when auth+ciph are complete) */
int (*tx_common_id)(void *msc_conn_ref);
@@ -433,6 +433,7 @@ int vlr_set_ciph_mode(struct vlr_instance *vlr,
struct osmo_fsm_inst *fi,
void *msc_conn_ref,
enum vlr_ciph ciph_mode,
+ bool umts_aka,
bool retrieve_imeisv);
bool vlr_use_umts_aka(struct osmo_auth_vector *vec, bool is_r99);
diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index d2c56c5a8..472acf00d 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -3388,6 +3388,7 @@ osmo_static_assert(sizeof(((struct gsm0808_encrypt_info*)0)->key) >= sizeof(((st
/* VLR asks us to start using ciphering */
static int msc_vlr_set_ciph_mode(void *msc_conn_ref,
enum vlr_ciph ciph,
+ bool umts_aka,
bool retrieve_imeisv)
struct gsm_subscriber_connection *conn = msc_conn_ref;
diff --git a/src/libvlr/vlr.c b/src/libvlr/vlr.c
index 55b8de006..670ff839d 100644
--- a/src/libvlr/vlr.c
+++ b/src/libvlr/vlr.c
@@ -1096,6 +1096,7 @@ int vlr_set_ciph_mode(struct vlr_instance *vlr,
struct osmo_fsm_inst *fi,
void *msc_conn_ref,
enum vlr_ciph ciph_mode,
+ bool umts_aka,
bool retrieve_imeisv)
switch (ciph_mode) {
@@ -1108,6 +1109,7 @@ int vlr_set_ciph_mode(struct vlr_instance *vlr,
ciph_mode, vlr_ciph_name(ciph_mode));
return vlr->ops.set_ciph_mode(msc_conn_ref,
+ umts_aka,
case VLR_CIPH_A5_2:
diff --git a/src/libvlr/vlr_access_req_fsm.c b/src/libvlr/vlr_access_req_fsm.c
index e90d8de9f..41e629ed2 100644
--- a/src/libvlr/vlr_access_req_fsm.c
+++ b/src/libvlr/vlr_access_req_fsm.c
@@ -294,6 +294,7 @@ static void _proc_arq_vlr_node2(struct osmo_fsm_inst *fi)
if (vlr_set_ciph_mode(vsub->vlr, fi, par->msc_conn_ref,
+ vlr_use_umts_aka(&vsub->last_tuple->vec, par->is_r99),
vsub->vlr->cfg.retrieve_imeisv_ciphered)) {
"Failed to send Ciphering Mode Command\n");
diff --git a/src/libvlr/vlr_lu_fsm.c b/src/libvlr/vlr_lu_fsm.c
index a3a68ed98..e540e2ae9 100644
--- a/src/libvlr/vlr_lu_fsm.c
+++ b/src/libvlr/vlr_lu_fsm.c
@@ -826,8 +826,15 @@ static void vlr_loc_upd_post_auth(struct osmo_fsm_inst *fi)
+ if (!vsub->last_tuple) {
+ LOGPFSML(fi, LOGL_ERROR, "No auth tuple available\n");
+ vlr_lu_compl_fsm_failure(fi, GSM48_REJECT_NETWORK_FAILURE);
+ return;
+ }
if (vlr_set_ciph_mode(vsub->vlr, fi, lfp->msc_conn_ref,
+ vlr_use_umts_aka(&vsub->last_tuple->vec, lfp->is_r99),
vsub->vlr->cfg.retrieve_imeisv_ciphered)) {
"Failed to send Ciphering Mode Command\n");
diff --git a/tests/msc_vlr/msc_vlr_tests.c b/tests/msc_vlr/msc_vlr_tests.c
index f0a112b2a..9cc61b156 100644
--- a/tests/msc_vlr/msc_vlr_tests.c
+++ b/tests/msc_vlr/msc_vlr_tests.c
@@ -665,7 +665,7 @@ static int fake_vlr_tx_auth_rej(void *msc_conn_ref)
static int fake_vlr_tx_ciph_mode_cmd(void *msc_conn_ref, enum vlr_ciph ciph,
- bool retrieve_imeisv)
+ bool umts_aka, bool retrieve_imeisv)
/* FIXME: we actually would like to see the message bytes checked here,
* not possible while msc_vlr_set_ciph_mode() calls