hostap/src/eap_common/eap_fast_common.c

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/*
* EAP-FAST common helper functions (RFC 4851)
* Copyright (c) 2008, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/sha1.h"
#include "crypto/tls.h"
#include "eap_defs.h"
#include "eap_tlv_common.h"
#include "eap_fast_common.h"
void eap_fast_put_tlv_hdr(struct wpabuf *buf, u16 type, u16 len)
{
struct pac_tlv_hdr hdr;
hdr.type = host_to_be16(type);
hdr.len = host_to_be16(len);
wpabuf_put_data(buf, &hdr, sizeof(hdr));
}
void eap_fast_put_tlv(struct wpabuf *buf, u16 type, const void *data,
u16 len)
{
eap_fast_put_tlv_hdr(buf, type, len);
wpabuf_put_data(buf, data, len);
}
void eap_fast_put_tlv_buf(struct wpabuf *buf, u16 type,
const struct wpabuf *data)
{
eap_fast_put_tlv_hdr(buf, type, wpabuf_len(data));
wpabuf_put_buf(buf, data);
}
struct wpabuf * eap_fast_tlv_eap_payload(struct wpabuf *buf)
{
struct wpabuf *e;
if (buf == NULL)
return NULL;
/* Encapsulate EAP packet in EAP-Payload TLV */
wpa_printf(MSG_DEBUG, "EAP-FAST: Add EAP-Payload TLV");
e = wpabuf_alloc(sizeof(struct pac_tlv_hdr) + wpabuf_len(buf));
if (e == NULL) {
wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to allocate memory "
"for TLV encapsulation");
wpabuf_free(buf);
return NULL;
}
eap_fast_put_tlv_buf(e,
EAP_TLV_TYPE_MANDATORY | EAP_TLV_EAP_PAYLOAD_TLV,
buf);
wpabuf_free(buf);
return e;
}
void eap_fast_derive_master_secret(const u8 *pac_key, const u8 *server_random,
const u8 *client_random, u8 *master_secret)
{
#define TLS_RANDOM_LEN 32
#define TLS_MASTER_SECRET_LEN 48
u8 seed[2 * TLS_RANDOM_LEN];
wpa_hexdump(MSG_DEBUG, "EAP-FAST: client_random",
client_random, TLS_RANDOM_LEN);
wpa_hexdump(MSG_DEBUG, "EAP-FAST: server_random",
server_random, TLS_RANDOM_LEN);
/*
* RFC 4851, Section 5.1:
* master_secret = T-PRF(PAC-Key, "PAC to master secret label hash",
* server_random + client_random, 48)
*/
os_memcpy(seed, server_random, TLS_RANDOM_LEN);
os_memcpy(seed + TLS_RANDOM_LEN, client_random, TLS_RANDOM_LEN);
sha1_t_prf(pac_key, EAP_FAST_PAC_KEY_LEN,
"PAC to master secret label hash",
seed, sizeof(seed), master_secret, TLS_MASTER_SECRET_LEN);
wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: master_secret",
master_secret, TLS_MASTER_SECRET_LEN);
}
u8 * eap_fast_derive_key(void *ssl_ctx, struct tls_connection *conn, size_t len)
{
u8 *out;
out = os_malloc(len);
if (out == NULL)
return NULL;
if (tls_connection_get_eap_fast_key(ssl_ctx, conn, out, len)) {
os_free(out);
return NULL;
}
return out;
}
int eap_fast_derive_eap_msk(const u8 *simck, u8 *msk)
{
/*
* RFC 4851, Section 5.4: EAP Master Session Key Generation
* MSK = T-PRF(S-IMCK[j], "Session Key Generating Function", 64)
*/
if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
"Session Key Generating Function", (u8 *) "", 0,
msk, EAP_FAST_KEY_LEN) < 0)
return -1;
wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (MSK)",
msk, EAP_FAST_KEY_LEN);
return 0;
}
int eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk)
{
/*
* RFC 4851, Section 5.4: EAP Master Session Key Genreration
* EMSK = T-PRF(S-IMCK[j],
* "Extended Session Key Generating Function", 64)
*/
if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
"Extended Session Key Generating Function", (u8 *) "", 0,
emsk, EAP_EMSK_LEN) < 0)
return -1;
wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (EMSK)",
emsk, EAP_EMSK_LEN);
return 0;
}
int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv,
int tlv_type, u8 *pos, size_t len)
{
switch (tlv_type) {
case EAP_TLV_EAP_PAYLOAD_TLV:
wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: EAP-Payload TLV",
pos, len);
if (tlv->eap_payload_tlv) {
wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
"EAP-Payload TLV in the message");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
return -2;
}
tlv->eap_payload_tlv = pos;
tlv->eap_payload_tlv_len = len;
break;
case EAP_TLV_RESULT_TLV:
wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Result TLV", pos, len);
if (tlv->result) {
wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
"Result TLV in the message");
tlv->result = EAP_TLV_RESULT_FAILURE;
return -2;
}
if (len < 2) {
wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
"Result TLV");
tlv->result = EAP_TLV_RESULT_FAILURE;
break;
}
tlv->result = WPA_GET_BE16(pos);
if (tlv->result != EAP_TLV_RESULT_SUCCESS &&
tlv->result != EAP_TLV_RESULT_FAILURE) {
wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Result %d",
tlv->result);
tlv->result = EAP_TLV_RESULT_FAILURE;
}
wpa_printf(MSG_DEBUG, "EAP-FAST: Result: %s",
tlv->result == EAP_TLV_RESULT_SUCCESS ?
"Success" : "Failure");
break;
case EAP_TLV_INTERMEDIATE_RESULT_TLV:
wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Intermediate Result TLV",
pos, len);
if (len < 2) {
wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
"Intermediate-Result TLV");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
break;
}
if (tlv->iresult) {
wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
"Intermediate-Result TLV in the message");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
return -2;
}
tlv->iresult = WPA_GET_BE16(pos);
if (tlv->iresult != EAP_TLV_RESULT_SUCCESS &&
tlv->iresult != EAP_TLV_RESULT_FAILURE) {
wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Intermediate "
"Result %d", tlv->iresult);
tlv->iresult = EAP_TLV_RESULT_FAILURE;
}
wpa_printf(MSG_DEBUG, "EAP-FAST: Intermediate Result: %s",
tlv->iresult == EAP_TLV_RESULT_SUCCESS ?
"Success" : "Failure");
break;
case EAP_TLV_CRYPTO_BINDING_TLV:
wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV",
pos, len);
if (tlv->crypto_binding) {
wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
"Crypto-Binding TLV in the message");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
return -2;
}
tlv->crypto_binding_len = sizeof(struct eap_tlv_hdr) + len;
if (tlv->crypto_binding_len < sizeof(*tlv->crypto_binding)) {
wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
"Crypto-Binding TLV");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
return -2;
}
tlv->crypto_binding = (struct eap_tlv_crypto_binding_tlv *)
(pos - sizeof(struct eap_tlv_hdr));
break;
case EAP_TLV_REQUEST_ACTION_TLV:
wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Request-Action TLV",
pos, len);
if (tlv->request_action) {
wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
"Request-Action TLV in the message");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
return -2;
}
if (len < 2) {
wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
"Request-Action TLV");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
break;
}
tlv->request_action = WPA_GET_BE16(pos);
wpa_printf(MSG_DEBUG, "EAP-FAST: Request-Action: %d",
tlv->request_action);
break;
case EAP_TLV_PAC_TLV:
wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: PAC TLV", pos, len);
if (tlv->pac) {
wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
"PAC TLV in the message");
tlv->iresult = EAP_TLV_RESULT_FAILURE;
return -2;
}
tlv->pac = pos;
tlv->pac_len = len;
break;
default:
/* Unknown TLV */
return -1;
}
return 0;
}