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EAP-SAKE: Report hash function failures to callers

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While this is mostly theoretical, the hash functions can fail and it is
better for the upper layer code to explicitly check for such failures.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2019-04-19 16:50:42 +03:00
parent 24b06511e2
commit 848718ddde
4 changed files with 82 additions and 53 deletions
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47
src/eap_common/eap_sake_common.c
View file

@ -1,6 +1,6 @@
/*
* EAP server/peer: EAP-SAKE shared routines
* Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
* Copyright (c) 2006-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@ -201,11 +201,12 @@ int eap_sake_parse_attributes(const u8 *buf, size_t len,
* @data2_len: Length of the data2
* @buf: Buffer for the generated pseudo-random key
* @buf_len: Number of bytes of key to generate
* Returns: 0 on success or -1 on failure
*
* This function is used to derive new, cryptographically separate keys from a
* given key (e.g., SMS). This is identical to the PRF used in IEEE 802.11i.
*/
static void eap_sake_kdf(const u8 *key, size_t key_len, const char *label,
static int eap_sake_kdf(const u8 *key, size_t key_len, const char *label,
const u8 *data, size_t data_len,
const u8 *data2, size_t data2_len,
u8 *buf, size_t buf_len)
@ -230,17 +231,21 @@ static void eap_sake_kdf(const u8 *key, size_t key_len, const char *label,
while (pos < buf_len) {
plen = buf_len - pos;
if (plen >= SHA1_MAC_LEN) {
hmac_sha1_vector(key, key_len, 4, addr, len,
&buf[pos]);
if (hmac_sha1_vector(key, key_len, 4, addr, len,
&buf[pos]) < 0)
return -1;
pos += SHA1_MAC_LEN;
} else {
hmac_sha1_vector(key, key_len, 4, addr, len,
hash);
if (hmac_sha1_vector(key, key_len, 4, addr, len,
hash) < 0)
return -1;
os_memcpy(&buf[pos], hash, plen);
break;
}
counter++;
}
return 0;
}
@ -253,10 +258,11 @@ static void eap_sake_kdf(const u8 *key, size_t key_len, const char *label,
* @tek: Buffer for Temporary EAK Keys (TEK-Auth[16] | TEK-Cipher[16])
* @msk: Buffer for 64-byte MSK
* @emsk: Buffer for 64-byte EMSK
* Returns: 0 on success or -1 on failure
*
* This function derives EAP-SAKE keys as defined in RFC 4763, section 3.2.6.
*/
void eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
int eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
const u8 *rand_s, const u8 *rand_p, u8 *tek, u8 *msk,
u8 *emsk)
{
@ -268,14 +274,16 @@ void eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: Root-Secret-A",
root_secret_a, EAP_SAKE_ROOT_SECRET_LEN);
eap_sake_kdf(root_secret_a, EAP_SAKE_ROOT_SECRET_LEN,
if (eap_sake_kdf(root_secret_a, EAP_SAKE_ROOT_SECRET_LEN,
"SAKE Master Secret A",
rand_p, EAP_SAKE_RAND_LEN, rand_s, EAP_SAKE_RAND_LEN,
sms_a, EAP_SAKE_SMS_LEN);
sms_a, EAP_SAKE_SMS_LEN) < 0)
return -1;
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: SMS-A", sms_a, EAP_SAKE_SMS_LEN);
eap_sake_kdf(sms_a, EAP_SAKE_SMS_LEN, "Transient EAP Key",
if (eap_sake_kdf(sms_a, EAP_SAKE_SMS_LEN, "Transient EAP Key",
rand_s, EAP_SAKE_RAND_LEN, rand_p, EAP_SAKE_RAND_LEN,
tek, EAP_SAKE_TEK_LEN);
tek, EAP_SAKE_TEK_LEN) < 0)
return -1;
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: TEK-Auth",
tek, EAP_SAKE_TEK_AUTH_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: TEK-Cipher",
@ -283,18 +291,21 @@ void eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: Root-Secret-B",
root_secret_b, EAP_SAKE_ROOT_SECRET_LEN);
eap_sake_kdf(root_secret_b, EAP_SAKE_ROOT_SECRET_LEN,
if (eap_sake_kdf(root_secret_b, EAP_SAKE_ROOT_SECRET_LEN,
"SAKE Master Secret B",
rand_p, EAP_SAKE_RAND_LEN, rand_s, EAP_SAKE_RAND_LEN,
sms_b, EAP_SAKE_SMS_LEN);
sms_b, EAP_SAKE_SMS_LEN) < 0)
return -1;
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: SMS-B", sms_b, EAP_SAKE_SMS_LEN);
eap_sake_kdf(sms_b, EAP_SAKE_SMS_LEN, "Master Session Key",
if (eap_sake_kdf(sms_b, EAP_SAKE_SMS_LEN, "Master Session Key",
rand_s, EAP_SAKE_RAND_LEN, rand_p, EAP_SAKE_RAND_LEN,
key_buf, sizeof(key_buf));
key_buf, sizeof(key_buf)) < 0)
return -1;
os_memcpy(msk, key_buf, EAP_MSK_LEN);
os_memcpy(emsk, key_buf + EAP_MSK_LEN, EAP_EMSK_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: MSK", msk, EAP_MSK_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: EMSK", emsk, EAP_EMSK_LEN);
return 0;
}
@ -312,6 +323,7 @@ void eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
* @eap_len: EAP packet length
* @mic_pos: MIC position in the EAP packet (must be [eap .. eap + eap_len])
* @mic: Buffer for the computed 16-byte MIC
* Returns: 0 on success or -1 on failure
*/
int eap_sake_compute_mic(const u8 *tek_auth,
const u8 *rand_s, const u8 *rand_p,
@ -323,6 +335,7 @@ int eap_sake_compute_mic(const u8 *tek_auth,
u8 _rand[2 * EAP_SAKE_RAND_LEN];
u8 *tmp, *pos;
size_t tmplen;
int ret;
tmplen = serverid_len + 1 + peerid_len + 1 + eap_len;
tmp = os_malloc(tmplen);
@ -364,14 +377,14 @@ int eap_sake_compute_mic(const u8 *tek_auth,
os_memcpy(pos, eap, eap_len);
os_memset(pos + (mic_pos - eap), 0, EAP_SAKE_MIC_LEN);
eap_sake_kdf(tek_auth, EAP_SAKE_TEK_AUTH_LEN,
ret = eap_sake_kdf(tek_auth, EAP_SAKE_TEK_AUTH_LEN,
peer ? "Peer MIC" : "Server MIC",
_rand, 2 * EAP_SAKE_RAND_LEN, tmp, tmplen,
mic, EAP_SAKE_MIC_LEN);
os_free(tmp);
return 0;
return ret;
}

4
src/eap_common/eap_sake_common.h
View file

@ -1,6 +1,6 @@
/*
* EAP server/peer: EAP-SAKE shared routines
* Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
* Copyright (c) 2006-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@ -81,7 +81,7 @@ struct eap_sake_parse_attr {
int eap_sake_parse_attributes(const u8 *buf, size_t len,
struct eap_sake_parse_attr *attr);
void eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
int eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
const u8 *rand_s, const u8 *rand_p,
u8 *tek, u8 *msk, u8 *emsk);
int eap_sake_compute_mic(const u8 *tek_auth,

10
src/eap_peer/eap_sake.c
View file

@ -1,6 +1,6 @@
/*
* EAP peer method: EAP-SAKE (RFC 4763)
* Copyright (c) 2006-2008, Jouni Malinen <j@w1.fi>
* Copyright (c) 2006-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@ -235,9 +235,13 @@ static struct wpabuf * eap_sake_process_challenge(struct eap_sm *sm,
data->serverid_len = attr.serverid_len;
}
eap_sake_derive_keys(data->root_secret_a, data->root_secret_b,
if (eap_sake_derive_keys(data->root_secret_a, data->root_secret_b,
data->rand_s, data->rand_p,
(u8 *) &data->tek, data->msk, data->emsk);
(u8 *) &data->tek, data->msk,
data->emsk) < 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Failed to derive keys");
return NULL;
}
wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Challenge");

24
src/eap_server/eap_server_sake.c
View file

@ -340,16 +340,25 @@ static void eap_sake_process_challenge(struct eap_sm *sm,
data->state = FAILURE;
return;
}
eap_sake_derive_keys(sm->user->password,
if (eap_sake_derive_keys(sm->user->password,
sm->user->password + EAP_SAKE_ROOT_SECRET_LEN,
data->rand_s, data->rand_p,
(u8 *) &data->tek, data->msk, data->emsk);
(u8 *) &data->tek, data->msk,
data->emsk) < 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Failed to derive keys");
data->state = FAILURE;
return;
}
eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
sm->server_id, sm->server_id_len,
data->peerid, data->peerid_len, 1,
wpabuf_head(respData), wpabuf_len(respData),
attr.mic_p, mic_p);
attr.mic_p, mic_p) < 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
data->state = FAILURE;
return;
}
if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
eap_sake_state(data, FAILURE);
@ -382,11 +391,14 @@ static void eap_sake_process_confirm(struct eap_sm *sm,
return;
}
eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
sm->server_id, sm->server_id_len,
data->peerid, data->peerid_len, 1,
wpabuf_head(respData), wpabuf_len(respData),
attr.mic_p, mic_p);
attr.mic_p, mic_p) < 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
return;
}
if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
eap_sake_state(data, FAILURE);