1189251Ssam/* 2189251Ssam * EAP server/peer: EAP-PAX shared routines 3189251Ssam * Copyright (c) 2005, Jouni Malinen <j@w1.fi> 4189251Ssam * 5189251Ssam * This program is free software; you can redistribute it and/or modify 6189251Ssam * it under the terms of the GNU General Public License version 2 as 7189251Ssam * published by the Free Software Foundation. 8189251Ssam * 9189251Ssam * Alternatively, this software may be distributed under the terms of BSD 10189251Ssam * license. 11189251Ssam * 12189251Ssam * See README and COPYING for more details. 13189251Ssam */ 14189251Ssam 15189251Ssam#include "includes.h" 16189251Ssam 17189251Ssam#include "common.h" 18214734Srpaulo#include "crypto/sha1.h" 19189251Ssam#include "eap_pax_common.h" 20189251Ssam 21189251Ssam 22189251Ssam/** 23189251Ssam * eap_pax_kdf - PAX Key Derivation Function 24189251Ssam * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported 25189251Ssam * @key: Secret key (X) 26189251Ssam * @key_len: Length of the secret key in bytes 27189251Ssam * @identifier: Public identifier for the key (Y) 28189251Ssam * @entropy: Exchanged entropy to seed the KDF (Z) 29189251Ssam * @entropy_len: Length of the entropy in bytes 30189251Ssam * @output_len: Output len in bytes (W) 31189251Ssam * @output: Buffer for the derived key 32189251Ssam * Returns: 0 on success, -1 failed 33189251Ssam * 34189251Ssam * RFC 4746, Section 2.6: PAX-KDF-W(X, Y, Z) 35189251Ssam */ 36189251Ssamint eap_pax_kdf(u8 mac_id, const u8 *key, size_t key_len, 37189251Ssam const char *identifier, 38189251Ssam const u8 *entropy, size_t entropy_len, 39189251Ssam size_t output_len, u8 *output) 40189251Ssam{ 41189251Ssam u8 mac[SHA1_MAC_LEN]; 42189251Ssam u8 counter, *pos; 43189251Ssam const u8 *addr[3]; 44189251Ssam size_t len[3]; 45189251Ssam size_t num_blocks, left; 46189251Ssam 47189251Ssam num_blocks = (output_len + EAP_PAX_MAC_LEN - 1) / EAP_PAX_MAC_LEN; 48189251Ssam if (identifier == NULL || num_blocks >= 255) 49189251Ssam return -1; 50189251Ssam 51189251Ssam /* TODO: add support for EAP_PAX_HMAC_SHA256_128 */ 52189251Ssam if (mac_id != EAP_PAX_MAC_HMAC_SHA1_128) 53189251Ssam return -1; 54189251Ssam 55189251Ssam addr[0] = (const u8 *) identifier; 56189251Ssam len[0] = os_strlen(identifier); 57189251Ssam addr[1] = entropy; 58189251Ssam len[1] = entropy_len; 59189251Ssam addr[2] = &counter; 60189251Ssam len[2] = 1; 61189251Ssam 62189251Ssam pos = output; 63189251Ssam left = output_len; 64189251Ssam for (counter = 1; counter <= (u8) num_blocks; counter++) { 65189251Ssam size_t clen = left > EAP_PAX_MAC_LEN ? EAP_PAX_MAC_LEN : left; 66189251Ssam hmac_sha1_vector(key, key_len, 3, addr, len, mac); 67189251Ssam os_memcpy(pos, mac, clen); 68189251Ssam pos += clen; 69189251Ssam left -= clen; 70189251Ssam } 71189251Ssam 72189251Ssam return 0; 73189251Ssam} 74189251Ssam 75189251Ssam 76189251Ssam/** 77189251Ssam * eap_pax_mac - EAP-PAX MAC 78189251Ssam * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported 79189251Ssam * @key: Secret key 80189251Ssam * @key_len: Length of the secret key in bytes 81189251Ssam * @data1: Optional data, first block; %NULL if not used 82189251Ssam * @data1_len: Length of data1 in bytes 83189251Ssam * @data2: Optional data, second block; %NULL if not used 84189251Ssam * @data2_len: Length of data2 in bytes 85189251Ssam * @data3: Optional data, third block; %NULL if not used 86189251Ssam * @data3_len: Length of data3 in bytes 87189251Ssam * @mac: Buffer for the MAC value (EAP_PAX_MAC_LEN = 16 bytes) 88189251Ssam * Returns: 0 on success, -1 on failure 89189251Ssam * 90189251Ssam * Wrapper function to calculate EAP-PAX MAC. 91189251Ssam */ 92189251Ssamint eap_pax_mac(u8 mac_id, const u8 *key, size_t key_len, 93189251Ssam const u8 *data1, size_t data1_len, 94189251Ssam const u8 *data2, size_t data2_len, 95189251Ssam const u8 *data3, size_t data3_len, 96189251Ssam u8 *mac) 97189251Ssam{ 98189251Ssam u8 hash[SHA1_MAC_LEN]; 99189251Ssam const u8 *addr[3]; 100189251Ssam size_t len[3]; 101189251Ssam size_t count; 102189251Ssam 103189251Ssam /* TODO: add support for EAP_PAX_HMAC_SHA256_128 */ 104189251Ssam if (mac_id != EAP_PAX_MAC_HMAC_SHA1_128) 105189251Ssam return -1; 106189251Ssam 107189251Ssam addr[0] = data1; 108189251Ssam len[0] = data1_len; 109189251Ssam addr[1] = data2; 110189251Ssam len[1] = data2_len; 111189251Ssam addr[2] = data3; 112189251Ssam len[2] = data3_len; 113189251Ssam 114189251Ssam count = (data1 ? 1 : 0) + (data2 ? 1 : 0) + (data3 ? 1 : 0); 115189251Ssam hmac_sha1_vector(key, key_len, count, addr, len, hash); 116189251Ssam os_memcpy(mac, hash, EAP_PAX_MAC_LEN); 117189251Ssam 118189251Ssam return 0; 119189251Ssam} 120189251Ssam 121189251Ssam 122189251Ssam/** 123189251Ssam * eap_pax_initial_key_derivation - EAP-PAX initial key derivation 124189251Ssam * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported 125189251Ssam * @ak: Authentication Key 126189251Ssam * @e: Entropy 127189251Ssam * @mk: Buffer for the derived Master Key 128189251Ssam * @ck: Buffer for the derived Confirmation Key 129189251Ssam * @ick: Buffer for the derived Integrity Check Key 130189251Ssam * Returns: 0 on success, -1 on failure 131189251Ssam */ 132189251Ssamint eap_pax_initial_key_derivation(u8 mac_id, const u8 *ak, const u8 *e, 133189251Ssam u8 *mk, u8 *ck, u8 *ick) 134189251Ssam{ 135189251Ssam wpa_printf(MSG_DEBUG, "EAP-PAX: initial key derivation"); 136189251Ssam if (eap_pax_kdf(mac_id, ak, EAP_PAX_AK_LEN, "Master Key", 137189251Ssam e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_MK_LEN, mk) || 138189251Ssam eap_pax_kdf(mac_id, mk, EAP_PAX_MK_LEN, "Confirmation Key", 139189251Ssam e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_CK_LEN, ck) || 140189251Ssam eap_pax_kdf(mac_id, mk, EAP_PAX_MK_LEN, "Integrity Check Key", 141189251Ssam e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_ICK_LEN, ick)) 142189251Ssam return -1; 143189251Ssam 144189251Ssam wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: AK", ak, EAP_PAX_AK_LEN); 145189251Ssam wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: MK", mk, EAP_PAX_MK_LEN); 146189251Ssam wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: CK", ck, EAP_PAX_CK_LEN); 147189251Ssam wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: ICK", ick, EAP_PAX_ICK_LEN); 148189251Ssam 149189251Ssam return 0; 150189251Ssam} 151