A CM service request must be acknowledged also, when encryption is already enabled.

Without encryption enabled, the security status is GSM_SECURITY_NOTAVAIL, which causes a CM service acknowledge. On initial CM service request, the security status is GSM_SECURITY_SUCCEED, if encryption is enabled. This will not lead to an acknowledge, because the cyphering command implies an acknowlege. An additional CM service request requires an acknowledge, so I added a new security status: GSM_SECURITY_ALREADY --- openbsc/include/openbsc/gsm_data.h | 1 + openbsc/src/libmsc/gsm_04_08.c | 8 +++++++- 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h index d7db887..05e0490 100644 --- a/openbsc/include/openbsc/gsm_data.h +++ b/openbsc/include/openbsc/gsm_data.h @@ -21,6 +21,7 @@ enum gsm_security_event { GSM_SECURITY_NOAVAIL, GSM_SECURITY_AUTH_FAILED, GSM_SECURITY_SUCCEEDED, + GSM_SECURITY_ALREADY, };

struct msgb; diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c index 58107e3..3725eb9 100644 --- a/openbsc/src/libmsc/gsm_04_08.c +++ b/openbsc/src/libmsc/gsm_04_08.c @@ -194,7 +194,7 @@ int gsm48_secure_channel(struct gsm_subscriber_connection *conn, int key_seq, status = GSM_SECURITY_NOAVAIL; } else if (conn->lchan->encr.alg_id > RSL_ENC_ALG_A5(0)) { DEBUGP(DMM, "Requesting to secure an already secure channel"); - status = GSM_SECURITY_SUCCEEDED; + status = GSM_SECURITY_ALREADY; } else if (!ms_cm2_a5n_support(subscr->equipment.classmark2, net->a5_encryption)) { DEBUGP(DMM, "Subscriber equipment doesn't support requested encryption"); @@ -302,6 +302,11 @@ static int _gsm0408_authorize_sec_cb(unsigned int hooknum, unsigned int event, release_loc_updating_req(conn); break;

+ case GSM_SECURITY_ALREADY: + LOGP(DMM, LOGL_ERROR, "We don't expect LOCATION " + "UPDATING after CM SERVICE REQUEST\n"); + /* fall through */ + case GSM_SECURITY_NOAVAIL: case GSM_SECURITY_SUCCEEDED: /* We're all good */ @@ -856,6 +861,7 @@ static int _gsm48_rx_mm_serv_req_sec_cb( break;

case GSM_SECURITY_NOAVAIL: + case GSM_SECURITY_ALREADY: rc = gsm48_tx_mm_serv_ack(conn); break;