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EAP-AKA': Added CK',IK' derivation

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This is based on a change request 3GPP TS 33.402 CR 0033 for version
8.1.1. The hardcoded ANID is now 'WLAN' since that is used in
3GPP TS 24.302.
This commit is contained in:
Jouni Malinen 2008-12-04 21:50:56 +02:00
parent a49c428a1b
commit a478ef0d12
4 changed files with 101 additions and 3 deletions
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70
src/eap_common/eap_sim_common.c
View file

@ -426,6 +426,76 @@ void eap_sim_add_mac_sha256(const u8 *k_aut, const u8 *msg, size_t msg_len,
wpa_hexdump(MSG_MSGDUMP, "EAP-AKA': Add MAC: MAC",
mac, EAP_SIM_MAC_LEN);
}
void eap_aka_prime_derive_ck_ik_prime(u8 *ck, u8 *ik, const u8 *sqn_ak,
const u8 *network_name,
size_t network_name_len)
{
u8 key[EAP_AKA_CK_LEN + EAP_AKA_IK_LEN];
u8 hash[SHA256_MAC_LEN];
const u8 *addr[5];
size_t len[5];
u8 fc;
u8 l0[2], l1[2];
/* 3GPP TS 33.402 V8.0.0
* (CK', IK') = F(CK, IK, <access network identity>)
*/
/* TODO: CK', IK' generation should really be moved into the actual
* AKA procedure with network name passed in there and option to use
* AMF separation bit = 1 (3GPP TS 33.401). */
/* Change Request 334.02 CR 0033 to version 8.1.1 from
* 3GPP TSG-SA WG3 Meeting #53 in September 2008:
*
* CK' || IK' = HMAC-SHA-256(Key, S)
* S = FC || P0 || L0 || P1 || L1 || ... || Pn || Ln
* Key = CK || IK
* FC = 0x20
* P0 = access network identity (3GPP TS 24.302)
* L0 = length of acceess network identity (2 octets, big endian)
* P1 = SQN xor AK (if AK is not used, AK is treaded as 000..0
* L1 = 0x00 0x06
*/
fc = 0x20;
wpa_printf(MSG_DEBUG, "EAP-AKA': Derive (CK',IK') from (CK,IK)");
wpa_hexdump_key(MSG_DEBUG, "EAP-AKA': CK", ck, EAP_AKA_CK_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-AKA': IK", ik, EAP_AKA_IK_LEN);
wpa_printf(MSG_DEBUG, "EAP-AKA': FC = 0x%x", fc);
wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA': P0 = Access network identity",
network_name, network_name_len);
wpa_hexdump(MSG_DEBUG, "EAP-AKA': P1 = SQN xor AK", sqn_ak, 6);
os_memcpy(key, ck, EAP_AKA_CK_LEN);
os_memcpy(key + EAP_AKA_CK_LEN, ik, EAP_AKA_IK_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-AKA': Key = CK || IK",
key, sizeof(key));
addr[0] = &fc;
len[0] = 1;
addr[1] = network_name;
len[1] = network_name_len;
WPA_PUT_BE16(l0, network_name_len);
addr[2] = l0;
len[2] = 2;
addr[3] = sqn_ak;
len[3] = 6;
WPA_PUT_BE16(l1, 6);
addr[4] = l1;
len[4] = 2;
hmac_sha256_vector(key, sizeof(key), 5, addr, len, hash);
wpa_hexdump_key(MSG_DEBUG, "EAP-AKA': KDF output (CK' || IK')",
hash, sizeof(hash));
os_memcpy(ck, hash, EAP_AKA_CK_LEN);
os_memcpy(ik, hash + EAP_AKA_CK_LEN, EAP_AKA_IK_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-AKA': CK'", ck, EAP_AKA_CK_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-AKA': IK'", ik, EAP_AKA_IK_LEN);
}
#endif /* EAP_AKA_PRIME */

4
src/eap_common/eap_sim_common.h
View file

@ -106,6 +106,10 @@ int eap_sim_verify_mac_sha256(const u8 *k_aut, const struct wpabuf *req,
void eap_sim_add_mac_sha256(const u8 *k_aut, const u8 *msg, size_t msg_len,
u8 *mac, const u8 *extra, size_t extra_len);
void eap_aka_prime_derive_ck_ik_prime(u8 *ck, u8 *ik, const u8 *sqn_ak,
const u8 *network_name,
size_t network_name_len);
/* EAP-SIM/AKA Attributes (0..127 non-skippable) */
#define EAP_SIM_AT_RAND 1

10
src/eap_peer/eap_aka_prime.c
View file

@ -820,6 +820,16 @@ static struct wpabuf * eap_aka_process_challenge(struct eap_sm *sm,
return eap_aka_client_error(data, id,
EAP_AKA_UNABLE_TO_PROCESS_PACKET);
}
#ifdef EAP_AKA_PRIME
if (data->eap_method == EAP_TYPE_AKA_PRIME) {
/* Note: AUTN = (SQN ^ AK) || AMF || MAC which gives us the
* needed 6-octet SQN ^AK for CK',IK' derivation */
eap_aka_prime_derive_ck_ik_prime(data->ck, data->ik,
data->autn,
data->network_name,
data->network_name_len);
}
#endif /* EAP_AKA_PRIME */
if (data->last_eap_identity) {
identity = data->last_eap_identity;
identity_len = data->last_eap_identity_len;

20
src/eap_server/eap_aka_prime.c
View file

@ -122,6 +122,8 @@ static void * eap_aka_init(struct eap_sm *sm)
static void * eap_aka_prime_init(struct eap_sm *sm)
{
struct eap_aka_data *data;
/* TODO: make ANID configurable; see 3GPP TS 24.302 */
char *network_name = "WLAN";
if (sm->eap_sim_db_priv == NULL) {
wpa_printf(MSG_WARNING, "EAP-AKA: eap_sim_db not configured");
@ -133,13 +135,14 @@ static void * eap_aka_prime_init(struct eap_sm *sm)
return NULL;
data->eap_method = EAP_TYPE_AKA_PRIME;
data->network_name = os_malloc(3);
data->network_name = os_malloc(os_strlen(network_name));
if (data->network_name == NULL) {
os_free(data);
return NULL;
}
os_memcpy(data->network_name, "FOO", 3); /* FIX: 3GPP.24.302 */
data->network_name_len = 3;
data->network_name_len = os_strlen(network_name);
os_memcpy(data->network_name, network_name, data->network_name_len);
data->state = IDENTITY;
eap_aka_determine_identity(sm, data, 1, 0);
@ -666,6 +669,17 @@ static void eap_aka_determine_identity(struct eap_sm *sm,
return;
}
#ifdef EAP_AKA_PRIME
if (data->eap_method == EAP_TYPE_AKA_PRIME) {
/* Note: AUTN = (SQN ^ AK) || AMF || MAC which gives us the
* needed 6-octet SQN ^AK for CK',IK' derivation */
eap_aka_prime_derive_ck_ik_prime(data->ck, data->ik,
data->autn,
data->network_name,
data->network_name_len);
}
#endif /* EAP_AKA_PRIME */
data->reauth = NULL;
data->counter = 0; /* reset re-auth counter since this is full auth */