381 lines
10 KiB
C
381 lines
10 KiB
C
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/*
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* EAP server/peer: EAP-SAKE shared routines
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* Copyright (c) 2006, Jouni Malinen <j@w1.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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#include "includes.h"
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#include "common.h"
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#include "sha1.h"
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#include "eap_defs.h"
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#include "eap_sake_common.h"
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static int eap_sake_parse_add_attr(struct eap_sake_parse_attr *attr,
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const u8 *pos)
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{
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size_t i;
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switch (pos[0]) {
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case EAP_SAKE_AT_RAND_S:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_RAND_S");
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if (pos[1] != 2 + EAP_SAKE_RAND_LEN) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_RAND_S with "
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"invalid length %d", pos[1]);
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return -1;
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}
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attr->rand_s = pos + 2;
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break;
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case EAP_SAKE_AT_RAND_P:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_RAND_P");
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if (pos[1] != 2 + EAP_SAKE_RAND_LEN) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_RAND_P with "
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"invalid length %d", pos[1]);
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return -1;
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}
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attr->rand_p = pos + 2;
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break;
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case EAP_SAKE_AT_MIC_S:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_MIC_S");
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if (pos[1] != 2 + EAP_SAKE_MIC_LEN) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_MIC_S with "
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"invalid length %d", pos[1]);
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return -1;
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}
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attr->mic_s = pos + 2;
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break;
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case EAP_SAKE_AT_MIC_P:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_MIC_P");
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if (pos[1] != 2 + EAP_SAKE_MIC_LEN) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_MIC_P with "
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"invalid length %d", pos[1]);
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return -1;
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}
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attr->mic_p = pos + 2;
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break;
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case EAP_SAKE_AT_SERVERID:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_SERVERID");
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attr->serverid = pos + 2;
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attr->serverid_len = pos[1] - 2;
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break;
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case EAP_SAKE_AT_PEERID:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_PEERID");
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attr->peerid = pos + 2;
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attr->peerid_len = pos[1] - 2;
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break;
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case EAP_SAKE_AT_SPI_S:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_SPI_S");
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attr->spi_s = pos + 2;
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attr->spi_s_len = pos[1] - 2;
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break;
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case EAP_SAKE_AT_SPI_P:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_SPI_P");
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attr->spi_p = pos + 2;
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attr->spi_p_len = pos[1] - 2;
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break;
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case EAP_SAKE_AT_ANY_ID_REQ:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_ANY_ID_REQ");
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if (pos[1] != 4) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid AT_ANY_ID_REQ"
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" length %d", pos[1]);
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return -1;
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}
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attr->any_id_req = pos + 2;
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break;
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case EAP_SAKE_AT_PERM_ID_REQ:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_PERM_ID_REQ");
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if (pos[1] != 4) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid "
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"AT_PERM_ID_REQ length %d", pos[1]);
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return -1;
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}
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attr->perm_id_req = pos + 2;
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break;
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case EAP_SAKE_AT_ENCR_DATA:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_ENCR_DATA");
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attr->encr_data = pos + 2;
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attr->encr_data_len = pos[1] - 2;
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break;
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case EAP_SAKE_AT_IV:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_IV");
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attr->iv = pos + 2;
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attr->iv_len = pos[1] - 2;
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break;
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case EAP_SAKE_AT_PADDING:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_PADDING");
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for (i = 2; i < pos[1]; i++) {
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if (pos[i]) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_PADDING "
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"with non-zero pad byte");
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return -1;
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}
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}
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break;
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case EAP_SAKE_AT_NEXT_TMPID:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_NEXT_TMPID");
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attr->next_tmpid = pos + 2;
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attr->next_tmpid_len = pos[1] - 2;
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break;
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case EAP_SAKE_AT_MSK_LIFE:
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_IV");
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if (pos[1] != 6) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid "
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"AT_MSK_LIFE length %d", pos[1]);
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return -1;
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}
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attr->msk_life = pos + 2;
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break;
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default:
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if (pos[0] < 128) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Unknown non-skippable"
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" attribute %d", pos[0]);
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return -1;
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}
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring unknown skippable "
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"attribute %d", pos[0]);
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break;
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}
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if (attr->iv && !attr->encr_data) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_IV included without "
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"AT_ENCR_DATA");
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return -1;
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}
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return 0;
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}
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/**
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* eap_sake_parse_attributes - Parse EAP-SAKE attributes
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* @buf: Packet payload (starting with the first attribute)
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* @len: Payload length
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* @attr: Structure to be filled with found attributes
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* Returns: 0 on success or -1 on failure
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*/
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int eap_sake_parse_attributes(const u8 *buf, size_t len,
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struct eap_sake_parse_attr *attr)
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{
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const u8 *pos = buf, *end = buf + len;
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os_memset(attr, 0, sizeof(*attr));
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while (pos < end) {
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if (end - pos < 2) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Too short attribute");
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return -1;
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}
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if (pos[1] < 2) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid attribute "
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"length (%d)", pos[1]);
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return -1;
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}
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if (pos + pos[1] > end) {
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Attribute underflow");
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return -1;
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}
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if (eap_sake_parse_add_attr(attr, pos))
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return -1;
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pos += pos[1];
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}
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return 0;
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}
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/**
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* eap_sake_kdf - EAP-SAKE Key Derivation Function (KDF)
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* @key: Key for KDF
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* @key_len: Length of the key in bytes
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* @label: A unique label for each purpose of the KDF
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* @data: Extra data (start) to bind into the key
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* @data_len: Length of the data
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* @data2: Extra data (end) to bind into the key
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* @data2_len: Length of the data2
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* @buf: Buffer for the generated pseudo-random key
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* @buf_len: Number of bytes of key to generate
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*
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* This function is used to derive new, cryptographically separate keys from a
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* given key (e.g., SMS). This is identical to the PRF used in IEEE 802.11i.
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*/
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static void eap_sake_kdf(const u8 *key, size_t key_len, const char *label,
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const u8 *data, size_t data_len,
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const u8 *data2, size_t data2_len,
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u8 *buf, size_t buf_len)
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{
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u8 counter = 0;
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size_t pos, plen;
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u8 hash[SHA1_MAC_LEN];
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size_t label_len = os_strlen(label) + 1;
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const unsigned char *addr[4];
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size_t len[4];
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addr[0] = (u8 *) label; /* Label | Y */
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len[0] = label_len;
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addr[1] = data; /* Msg[start] */
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len[1] = data_len;
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addr[2] = data2; /* Msg[end] */
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len[2] = data2_len;
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addr[3] = &counter; /* Length */
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len[3] = 1;
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pos = 0;
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while (pos < buf_len) {
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plen = buf_len - pos;
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if (plen >= SHA1_MAC_LEN) {
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hmac_sha1_vector(key, key_len, 4, addr, len,
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&buf[pos]);
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pos += SHA1_MAC_LEN;
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} else {
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hmac_sha1_vector(key, key_len, 4, addr, len,
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hash);
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os_memcpy(&buf[pos], hash, plen);
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break;
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}
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counter++;
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}
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}
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/**
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* eap_sake_derive_keys - Derive EAP-SAKE keys
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* @root_secret_a: 16-byte Root-Secret-A
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* @root_secret_b: 16-byte Root-Secret-B
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* @rand_s: 16-byte RAND_S
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* @rand_p: 16-byte RAND_P
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* @tek: Buffer for Temporary EAK Keys (TEK-Auth[16] | TEK-Cipher[16])
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* @msk: Buffer for 64-byte MSK
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* @emsk: Buffer for 64-byte EMSK
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*
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* This function derives EAP-SAKE keys as defined in RFC 4763, section 3.2.6.
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*/
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void eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
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const u8 *rand_s, const u8 *rand_p, u8 *tek, u8 *msk,
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u8 *emsk)
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{
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u8 sms_a[EAP_SAKE_SMS_LEN];
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u8 sms_b[EAP_SAKE_SMS_LEN];
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u8 key_buf[EAP_MSK_LEN + EAP_EMSK_LEN];
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wpa_printf(MSG_DEBUG, "EAP-SAKE: Deriving keys");
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: Root-Secret-A",
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root_secret_a, EAP_SAKE_ROOT_SECRET_LEN);
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eap_sake_kdf(root_secret_a, EAP_SAKE_ROOT_SECRET_LEN,
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"SAKE Master Secret A",
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rand_p, EAP_SAKE_RAND_LEN, rand_s, EAP_SAKE_RAND_LEN,
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sms_a, EAP_SAKE_SMS_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: SMS-A", sms_a, EAP_SAKE_SMS_LEN);
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eap_sake_kdf(sms_a, EAP_SAKE_SMS_LEN, "Transient EAP Key",
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rand_s, EAP_SAKE_RAND_LEN, rand_p, EAP_SAKE_RAND_LEN,
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tek, EAP_SAKE_TEK_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: TEK-Auth",
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tek, EAP_SAKE_TEK_AUTH_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: TEK-Cipher",
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tek + EAP_SAKE_TEK_AUTH_LEN, EAP_SAKE_TEK_CIPHER_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: Root-Secret-B",
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root_secret_b, EAP_SAKE_ROOT_SECRET_LEN);
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eap_sake_kdf(root_secret_b, EAP_SAKE_ROOT_SECRET_LEN,
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"SAKE Master Secret B",
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rand_p, EAP_SAKE_RAND_LEN, rand_s, EAP_SAKE_RAND_LEN,
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sms_b, EAP_SAKE_SMS_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: SMS-B", sms_b, EAP_SAKE_SMS_LEN);
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eap_sake_kdf(sms_b, EAP_SAKE_SMS_LEN, "Master Session Key",
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rand_s, EAP_SAKE_RAND_LEN, rand_p, EAP_SAKE_RAND_LEN,
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key_buf, sizeof(key_buf));
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os_memcpy(msk, key_buf, EAP_MSK_LEN);
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os_memcpy(emsk, key_buf + EAP_MSK_LEN, EAP_EMSK_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: MSK", msk, EAP_MSK_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: EMSK", emsk, EAP_EMSK_LEN);
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}
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/**
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* eap_sake_compute_mic - Compute EAP-SAKE MIC for an EAP packet
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* @tek_auth: 16-byte TEK-Auth
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* @rand_s: 16-byte RAND_S
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* @rand_p: 16-byte RAND_P
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* @serverid: SERVERID
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* @serverid_len: SERVERID length
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* @peerid: PEERID
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* @peerid_len: PEERID length
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* @peer: MIC calculation for 0 = Server, 1 = Peer message
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* @eap: EAP packet
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* @eap_len: EAP packet length
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* @mic_pos: MIC position in the EAP packet (must be [eap .. eap + eap_len])
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* @mic: Buffer for the computed 16-byte MIC
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*/
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int eap_sake_compute_mic(const u8 *tek_auth,
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const u8 *rand_s, const u8 *rand_p,
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const u8 *serverid, size_t serverid_len,
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const u8 *peerid, size_t peerid_len,
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int peer, const u8 *eap, size_t eap_len,
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const u8 *mic_pos, u8 *mic)
|
||
|
|
{
|
||
|
|
u8 _rand[2 * EAP_SAKE_RAND_LEN];
|
||
|
|
u8 *tmp, *pos;
|
||
|
|
size_t tmplen;
|
||
|
|
|
||
|
|
tmplen = serverid_len + 1 + peerid_len + 1 + eap_len;
|
||
|
|
tmp = os_malloc(tmplen);
|
||
|
|
if (tmp == NULL)
|
||
|
|
return -1;
|
||
|
|
pos = tmp;
|
||
|
|
if (peer) {
|
||
|
|
if (peerid) {
|
||
|
|
os_memcpy(pos, peerid, peerid_len);
|
||
|
|
pos += peerid_len;
|
||
|
|
}
|
||
|
|
*pos++ = 0x00;
|
||
|
|
if (serverid) {
|
||
|
|
os_memcpy(pos, serverid, serverid_len);
|
||
|
|
pos += serverid_len;
|
||
|
|
}
|
||
|
|
*pos++ = 0x00;
|
||
|
|
|
||
|
|
os_memcpy(_rand, rand_s, EAP_SAKE_RAND_LEN);
|
||
|
|
os_memcpy(_rand + EAP_SAKE_RAND_LEN, rand_p,
|
||
|
|
EAP_SAKE_RAND_LEN);
|
||
|
|
} else {
|
||
|
|
if (serverid) {
|
||
|
|
os_memcpy(pos, serverid, serverid_len);
|
||
|
|
pos += serverid_len;
|
||
|
|
}
|
||
|
|
*pos++ = 0x00;
|
||
|
|
if (peerid) {
|
||
|
|
os_memcpy(pos, peerid, peerid_len);
|
||
|
|
pos += peerid_len;
|
||
|
|
}
|
||
|
|
*pos++ = 0x00;
|
||
|
|
|
||
|
|
os_memcpy(_rand, rand_p, EAP_SAKE_RAND_LEN);
|
||
|
|
os_memcpy(_rand + EAP_SAKE_RAND_LEN, rand_s,
|
||
|
|
EAP_SAKE_RAND_LEN);
|
||
|
|
}
|
||
|
|
|
||
|
|
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,
|
||
|
|
peer ? "Peer MIC" : "Server MIC",
|
||
|
|
_rand, 2 * EAP_SAKE_RAND_LEN, tmp, tmplen,
|
||
|
|
mic, EAP_SAKE_MIC_LEN);
|
||
|
|
|
||
|
|
os_free(tmp);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|