2 * EAP server/peer: EAP-PAX shared routines
3 * Copyright (c) 2005, Jouni Malinen <j@w1.fi>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
12 #include "crypto/sha1.h"
13 #include "eap_pax_common.h"
17 * eap_pax_kdf - PAX Key Derivation Function
18 * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported
19 * @key: Secret key (X)
20 * @key_len: Length of the secret key in bytes
21 * @identifier: Public identifier for the key (Y)
22 * @entropy: Exchanged entropy to seed the KDF (Z)
23 * @entropy_len: Length of the entropy in bytes
24 * @output_len: Output len in bytes (W)
25 * @output: Buffer for the derived key
26 * Returns: 0 on success, -1 failed
28 * RFC 4746, Section 2.6: PAX-KDF-W(X, Y, Z)
30 int eap_pax_kdf(u8 mac_id, const u8 *key, size_t key_len,
31 const char *identifier,
32 const u8 *entropy, size_t entropy_len,
33 size_t output_len, u8 *output)
39 size_t num_blocks, left;
41 num_blocks = (output_len + EAP_PAX_MAC_LEN - 1) / EAP_PAX_MAC_LEN;
42 if (identifier == NULL || num_blocks >= 255)
45 /* TODO: add support for EAP_PAX_HMAC_SHA256_128 */
46 if (mac_id != EAP_PAX_MAC_HMAC_SHA1_128)
49 addr[0] = (const u8 *) identifier;
50 len[0] = os_strlen(identifier);
58 for (counter = 1; counter <= (u8) num_blocks; counter++) {
59 size_t clen = left > EAP_PAX_MAC_LEN ? EAP_PAX_MAC_LEN : left;
60 hmac_sha1_vector(key, key_len, 3, addr, len, mac);
61 os_memcpy(pos, mac, clen);
71 * eap_pax_mac - EAP-PAX MAC
72 * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported
74 * @key_len: Length of the secret key in bytes
75 * @data1: Optional data, first block; %NULL if not used
76 * @data1_len: Length of data1 in bytes
77 * @data2: Optional data, second block; %NULL if not used
78 * @data2_len: Length of data2 in bytes
79 * @data3: Optional data, third block; %NULL if not used
80 * @data3_len: Length of data3 in bytes
81 * @mac: Buffer for the MAC value (EAP_PAX_MAC_LEN = 16 bytes)
82 * Returns: 0 on success, -1 on failure
84 * Wrapper function to calculate EAP-PAX MAC.
86 int eap_pax_mac(u8 mac_id, const u8 *key, size_t key_len,
87 const u8 *data1, size_t data1_len,
88 const u8 *data2, size_t data2_len,
89 const u8 *data3, size_t data3_len,
92 u8 hash[SHA1_MAC_LEN];
97 /* TODO: add support for EAP_PAX_HMAC_SHA256_128 */
98 if (mac_id != EAP_PAX_MAC_HMAC_SHA1_128)
108 count = (data1 ? 1 : 0) + (data2 ? 1 : 0) + (data3 ? 1 : 0);
109 hmac_sha1_vector(key, key_len, count, addr, len, hash);
110 os_memcpy(mac, hash, EAP_PAX_MAC_LEN);
117 * eap_pax_initial_key_derivation - EAP-PAX initial key derivation
118 * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported
119 * @ak: Authentication Key
121 * @mk: Buffer for the derived Master Key
122 * @ck: Buffer for the derived Confirmation Key
123 * @ick: Buffer for the derived Integrity Check Key
124 * Returns: 0 on success, -1 on failure
126 int eap_pax_initial_key_derivation(u8 mac_id, const u8 *ak, const u8 *e,
127 u8 *mk, u8 *ck, u8 *ick)
129 wpa_printf(MSG_DEBUG, "EAP-PAX: initial key derivation");
130 if (eap_pax_kdf(mac_id, ak, EAP_PAX_AK_LEN, "Master Key",
131 e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_MK_LEN, mk) ||
132 eap_pax_kdf(mac_id, mk, EAP_PAX_MK_LEN, "Confirmation Key",
133 e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_CK_LEN, ck) ||
134 eap_pax_kdf(mac_id, mk, EAP_PAX_MK_LEN, "Integrity Check Key",
135 e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_ICK_LEN, ick))
138 wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: AK", ak, EAP_PAX_AK_LEN);
139 wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: MK", mk, EAP_PAX_MK_LEN);
140 wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: CK", ck, EAP_PAX_CK_LEN);
141 wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: ICK", ick, EAP_PAX_ICK_LEN);