commit 7b222aa1062aae786c92ea649d945ae8d86bbba2
author Harald Welte <laforge@gnumonks.org> Sat Dec 23 19:30:32 2017 +0100
committer Harald Welte <laforge@gnumonks.org> Sun Jan 28 00:09:42 2018 +0000
tree cd6429a67e8d31508ef7eb2b3201bf3524cd7208
parent 71c51df07dfbc60cb41cb43385576a9d89c0c269

Permit a set of multiple different A5 ciphers

So far, the administrator had to pick one particular cipher which
would then be used throughout all subscribers/phones. This is a bit
impractical, as e.g. not all phones support A5/3.  Extend the VTY
command syntax in a backwards-compatible way to permit for multiple
ciphers.

NOTE: Like the previous code, OsmoMSC does *not yet check* whether
the configured cipher is compatible with the MS capabilities as
reported in CLASSMARK!  The network hence might choose an algorithm
not supported by the phone.  Fixing this is subject to another patch.

Closes: OS#2460
Change-Id: I79a4e2892eb5fbecc3d84e11dceffb7149db264b

src/libmsc/gsm_04_08.c

diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index c37aeb7..3574583 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -339,7 +339,7 @@
 				net->vlr, conn, vlr_lu_type, tmsi, imsi,
 				&old_lai, &new_lai,
 				is_utran || conn->network->authentication_required,
-				is_utran || conn->network->a5_encryption,
+				is_utran || conn->network->a5_encryption_mask > 0x01,
 				classmark_is_r99(&conn->classmark),
 				is_utran,
 				net->vlr->cfg.assign_tmsi);
@@ -723,7 +723,7 @@
 			 net->vlr, conn,
 			 VLR_PR_ARQ_T_CM_SERV_REQ, mi-1, &lai,
 			 is_utran || conn->network->authentication_required,
-			 is_utran || conn->network->a5_encryption,
+			 is_utran || conn->network->a5_encryption_mask > 0x01,
 			 classmark_is_r99(&conn->classmark),
 			 is_utran);
 
@@ -1127,7 +1127,7 @@
 			 net->vlr, conn,
 			 VLR_PR_ARQ_T_PAGING_RESP, mi_lv, &lai,
 			 is_utran || conn->network->authentication_required,
-			 is_utran || conn->network->a5_encryption,
+			 is_utran || conn->network->a5_encryption_mask > 0x01,
 			 classmark_is_r99(&conn->classmark),
 			 is_utran);
 
@@ -3447,10 +3447,15 @@
 		DEBUGP(DMM, "-> CIPHER MODE COMMAND %s\n",
 		       vlr_subscr_name(conn->vsub));
 		{
+			struct gsm_network *net = conn->network;
 			struct gsm0808_encrypt_info ei;
+			int i, j = 0;
 
-			ei.perm_algo[0] = vlr_ciph_to_gsm0808_alg_id(conn->network->a5_encryption);
-			ei.perm_algo_len = 1;
+			for (i = 0; i < 8; i++) {
+				if (net->a5_encryption_mask & (1 << i))
+					ei.perm_algo[j++] = vlr_ciph_to_gsm0808_alg_id(i);
+			}
+			ei.perm_algo_len = j;
 
 			/* 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