[MERGED] libosmocore[master]: auth_milenage: Fix non-AUTS case with OP

[Harald Welte]

Harald Welte has submitted this change and it was merged.

Change subject: auth_milenage: Fix non-AUTS case with OP
......................................................................


auth_milenage: Fix non-AUTS case with OP

We only implemented OPC generation from OP in the AUTS case, but not
in the case of normal authentication vector generation.  This never
really was visible so far due to the fact that we use OPC at sysmocom,
and never the shared OP value.

Change-Id: Id3fa038dfc2ff1ba63616fa5e8eab0520481ff26
---
M src/gsm/auth_milenage.c
1 file changed, 24 insertions(+), 12 deletions(-)

Approvals:
  Harald Welte: Looks good to me, approved
  Jenkins Builder: Verified



diff --git a/src/gsm/auth_milenage.c b/src/gsm/auth_milenage.c
index 8d50990..6dd4f45 100644
--- a/src/gsm/auth_milenage.c
+++ b/src/gsm/auth_milenage.c
@@ -30,16 +30,36 @@
  *  @{
  */
 
+static const uint8_t *gen_opc_if_needed(const struct osmo_sub_auth_data *aud, uint8_t *gen_opc)
+{
+	int rc;
+
+	/* Check if we only know OP and compute OPC if required */
+	if (aud->type == OSMO_AUTH_TYPE_UMTS && aud->u.umts.opc_is_op) {
+		rc = milenage_opc_gen(gen_opc, aud->u.umts.k, aud->u.umts.opc);
+		if (rc < 0)
+			return NULL;
+		return gen_opc;
+	} else
+		return aud->u.umts.opc;
+}
+
 static int milenage_gen_vec(struct osmo_auth_vector *vec,
 			    struct osmo_sub_auth_data *aud,
 			    const uint8_t *_rand)
 {
 	size_t res_len = sizeof(vec->res);
 	uint64_t next_sqn;
+	uint8_t gen_opc[16];
+	const uint8_t *opc;
 	uint8_t sqn[6];
 	uint64_t ind_mask;
 	uint64_t seq_1;
 	int rc;
+
+	opc = gen_opc_if_needed(aud, gen_opc);
+	if (!opc)
+		return -1;
 
 	/* Determine next SQN, according to 3GPP TS 33.102:
 	 * SQN consists of SEQ and a lower significant part of IND bits:
@@ -106,11 +126,11 @@
 	next_sqn = ((aud->u.umts.sqn + seq_1) & ind_mask) + aud->u.umts.ind;
 
 	osmo_store64be_ext(next_sqn, sqn, 6);
-	milenage_generate(aud->u.umts.opc, aud->u.umts.amf, aud->u.umts.k,
+	milenage_generate(opc, aud->u.umts.amf, aud->u.umts.k,
 			  sqn, _rand,
 			  vec->autn, vec->ik, vec->ck, vec->res, &res_len);
 	vec->res_len = res_len;
-	rc = gsm_milenage(aud->u.umts.opc, aud->u.umts.k, _rand, vec->sres, vec->kc);
+	rc = gsm_milenage(opc, aud->u.umts.k, _rand, vec->sres, vec->kc);
 	if (rc < 0)
 		return rc;
 
@@ -129,18 +149,10 @@
 {
 	uint8_t sqn_out[6];
 	uint8_t gen_opc[16];
-	uint8_t *opc;
+	const uint8_t *opc;
 	int rc;
 
-	/* Check if we only know OP and compute OPC if required */
-	if (aud->type == OSMO_AUTH_TYPE_UMTS && aud->u.umts.opc_is_op) {
-		rc = milenage_opc_gen(gen_opc, aud->u.umts.k,
-				      aud->u.umts.opc);
-		if (rc < 0)
-			return rc;
-		opc = gen_opc;
-	} else
-		opc = aud->u.umts.opc;
+	opc = gen_opc_if_needed(aud, gen_opc);
 
 	rc = milenage_auts(opc, aud->u.umts.k, rand_auts, auts, sqn_out);
 	if (rc < 0)

-- 
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Gerrit-MessageType: merged
Gerrit-Change-Id: Id3fa038dfc2ff1ba63616fa5e8eab0520481ff26
Gerrit-PatchSet: 2
Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Owner: Harald Welte <laforge at gnumonks.org>
Gerrit-Reviewer: Harald Welte <laforge at gnumonks.org>
Gerrit-Reviewer: Jenkins Builder