The Session-Id derivation for EAP-SIM in RFC 5247 only explained how the Session-Id is derived for regular authentication.
Jouni reported it as an errata with text explaining how to derive it during fast reauthentication.
This patch now exports the Session-Id for EAP-SIM during fast reauthentication.
Signed-off-by: Mohit Sethi <mohit.sethi@xxxxxxxx>
---
src/eap_peer/eap_sim.c | 38 ++++++++++++++++++++++++++++++--------
src/eap_server/eap_server_sim.c | 40 +++++++++++++++++++++++++++++++---------
2 files changed, 61 insertions(+), 17 deletions(-)
diff --git a/src/eap_peer/eap_sim.c b/src/eap_peer/eap_sim.c
index ba5eea9..3b09ee2 100644
--- a/src/eap_peer/eap_sim.c
+++ b/src/eap_peer/eap_sim.c
@@ -32,6 +32,7 @@ struct eap_sim_data {
u8 msk[EAP_SIM_KEYING_DATA_LEN];
u8 emsk[EAP_EMSK_LEN];
u8 rand[3][GSM_RAND_LEN];
+ u8 reauth_mac[EAP_SIM_MAC_LEN];
int num_id_req, num_notification;
u8 *pseudonym;
@@ -958,6 +959,15 @@ static struct wpabuf * eap_sim_process_reauthentication(
EAP_SIM_UNABLE_TO_PROCESS_PACKET);
}
+ /* At this stage the MAC received is verified. Use this mac for
+ * reauth Session-Id calculation if all other checks pass.
+ * Peer does not use local MAC but received MAC
+ * in deriving Session-Id */
+ os_memset(data->reauth_mac, 0, EAP_SIM_MAC_LEN);
+ os_memcpy(data->reauth_mac, attr->mac, EAP_SIM_MAC_LEN);
+ wpa_hexdump(MSG_DEBUG, "EAP-SIM: Server MAC", data->reauth_mac,
+ EAP_SIM_MAC_LEN);
+
if (attr->encr_data == NULL || attr->iv == NULL) {
wpa_printf(MSG_WARNING, "EAP-SIM: Reauthentication "
"message did not include encrypted data");
@@ -1215,16 +1225,28 @@ static u8 * eap_sim_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
if (data->state != SUCCESS)
return NULL;
+
+ if(!data->reauth) {
+ *len = 1 + data->num_chal * GSM_RAND_LEN + EAP_SIM_NONCE_MT_LEN;
+ id = os_malloc(*len);
+ if (id == NULL)
+ return NULL;
- *len = 1 + data->num_chal * GSM_RAND_LEN + EAP_SIM_NONCE_MT_LEN;
- id = os_malloc(*len);
- if (id == NULL)
- return NULL;
+ id[0] = EAP_TYPE_SIM;
+ os_memcpy(id + 1, data->rand, data->num_chal * GSM_RAND_LEN);
+ os_memcpy(id + 1 + data->num_chal * GSM_RAND_LEN, data->nonce_mt,
+ EAP_SIM_NONCE_MT_LEN);
+ } else {
+ *len = 1 + EAP_SIM_NONCE_S_LEN + EAP_SIM_MAC_LEN;
+ id = os_malloc(*len);
+ if (id == NULL)
+ return NULL;
- id[0] = EAP_TYPE_SIM;
- os_memcpy(id + 1, data->rand, data->num_chal * GSM_RAND_LEN);
- os_memcpy(id + 1 + data->num_chal * GSM_RAND_LEN, data->nonce_mt,
- EAP_SIM_NONCE_MT_LEN);
+ id[0] = EAP_TYPE_SIM;
+ os_memcpy(id + 1, data->nonce_s, EAP_SIM_NONCE_S_LEN);
+ os_memcpy(id + 1 + EAP_SIM_NONCE_S_LEN, data->reauth_mac,
+ EAP_SIM_MAC_LEN);
+ }
wpa_hexdump(MSG_DEBUG, "EAP-SIM: Derived Session-Id", id, *len);
return id;
diff --git a/src/eap_server/eap_server_sim.c b/src/eap_server/eap_server_sim.c
index 1287827..7ea208d 100644
--- a/src/eap_server/eap_server_sim.c
+++ b/src/eap_server/eap_server_sim.c
@@ -26,6 +26,7 @@ struct eap_sim_data {
u8 kc[EAP_SIM_MAX_CHAL][EAP_SIM_KC_LEN];
u8 sres[EAP_SIM_MAX_CHAL][EAP_SIM_SRES_LEN];
u8 rand[EAP_SIM_MAX_CHAL][GSM_RAND_LEN];
+ u8 reauth_mac[EAP_SIM_MAC_LEN];
int num_chal;
enum {
START, CHALLENGE, REAUTH, NOTIFICATION, SUCCESS, FAILURE
@@ -278,7 +279,15 @@ static struct wpabuf * eap_sim_build_reauth(struct eap_sm *sm,
wpa_printf(MSG_DEBUG, " AT_MAC");
eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
- return eap_sim_msg_finish(msg, EAP_TYPE_SIM, data->k_aut, NULL, 0);
+ struct wpabuf * buf = eap_sim_msg_finish(msg, EAP_TYPE_SIM, data->k_aut,
+ NULL, 0);
+
+ /* Remember this MAC before sending it to peer. This MAC is used for
+ * Session-Id calculation after receiving response peer and after all
+ * other checks pass. */
+ os_memset(data->reauth_mac, 0, EAP_SIM_MAC_LEN);
+ os_memcpy(data->reauth_mac, buf->buf + (int) (wpabuf_len(buf) -
+ EAP_SIM_MAC_LEN), EAP_SIM_MAC_LEN);
}
@@ -829,15 +838,28 @@ static u8 * eap_sim_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
if (data->state != SUCCESS)
return NULL;
- *len = 1 + data->num_chal * GSM_RAND_LEN + EAP_SIM_NONCE_MT_LEN;
- id = os_malloc(*len);
- if (id == NULL)
- return NULL;
+ if(!data->reauth) {
+ *len = 1 + data->num_chal * GSM_RAND_LEN + EAP_SIM_NONCE_MT_LEN;
+ id = os_malloc(*len);
+ if (id == NULL)
+ return NULL;
- id[0] = EAP_TYPE_SIM;
- os_memcpy(id + 1, data->rand, data->num_chal * GSM_RAND_LEN);
- os_memcpy(id + 1 + data->num_chal * GSM_RAND_LEN, data->nonce_mt,
- EAP_SIM_NONCE_MT_LEN);
+ id[0] = EAP_TYPE_SIM;
+ os_memcpy(id + 1, data->rand, data->num_chal * GSM_RAND_LEN);
+ os_memcpy(id + 1 + data->num_chal * GSM_RAND_LEN, data->nonce_mt,
+ EAP_SIM_NONCE_MT_LEN);
+ } else {
+ *len = 1 + EAP_SIM_NONCE_S_LEN + EAP_SIM_MAC_LEN;
+ id = os_malloc(*len);
+ if (id == NULL)
+ return NULL;
+
+ id[0] = EAP_TYPE_SIM;
+ os_memcpy(id + 1, data->nonce_s, EAP_SIM_NONCE_S_LEN);
+ os_memcpy(id + 1 + EAP_SIM_NONCE_S_LEN, data->reauth_mac,
+ EAP_SIM_MAC_LEN);
+
+ }
wpa_hexdump(MSG_DEBUG, "EAP-SIM: Derived Session-Id", id, *len);
return id;
--
2.7.4
_______________________________________________
Hostap mailing list
Hostap@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/hostap
