--- /dev/null
+/*
+ * EAP server/peer: EAP-PAX shared routines
+ * Copyright (c) 2005, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "crypto/sha1.h"
+#include "eap_pax_common.h"
+
+
+/**
+ * eap_pax_kdf - PAX Key Derivation Function
+ * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported
+ * @key: Secret key (X)
+ * @key_len: Length of the secret key in bytes
+ * @identifier: Public identifier for the key (Y)
+ * @entropy: Exchanged entropy to seed the KDF (Z)
+ * @entropy_len: Length of the entropy in bytes
+ * @output_len: Output len in bytes (W)
+ * @output: Buffer for the derived key
+ * Returns: 0 on success, -1 failed
+ *
+ * RFC 4746, Section 2.6: PAX-KDF-W(X, Y, Z)
+ */
+int eap_pax_kdf(u8 mac_id, const u8 *key, size_t key_len,
+ const char *identifier,
+ const u8 *entropy, size_t entropy_len,
+ size_t output_len, u8 *output)
+{
+ u8 mac[SHA1_MAC_LEN];
+ u8 counter, *pos;
+ const u8 *addr[3];
+ size_t len[3];
+ size_t num_blocks, left;
+
+ num_blocks = (output_len + EAP_PAX_MAC_LEN - 1) / EAP_PAX_MAC_LEN;
+ if (identifier == NULL || num_blocks >= 255)
+ return -1;
+
+ /* TODO: add support for EAP_PAX_HMAC_SHA256_128 */
+ if (mac_id != EAP_PAX_MAC_HMAC_SHA1_128)
+ return -1;
+
+ addr[0] = (const u8 *) identifier;
+ len[0] = os_strlen(identifier);
+ addr[1] = entropy;
+ len[1] = entropy_len;
+ addr[2] = &counter;
+ len[2] = 1;
+
+ pos = output;
+ left = output_len;
+ for (counter = 1; counter <= (u8) num_blocks; counter++) {
+ size_t clen = left > EAP_PAX_MAC_LEN ? EAP_PAX_MAC_LEN : left;
+ hmac_sha1_vector(key, key_len, 3, addr, len, mac);
+ os_memcpy(pos, mac, clen);
+ pos += clen;
+ left -= clen;
+ }
+
+ return 0;
+}
+
+
+/**
+ * eap_pax_mac - EAP-PAX MAC
+ * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported
+ * @key: Secret key
+ * @key_len: Length of the secret key in bytes
+ * @data1: Optional data, first block; %NULL if not used
+ * @data1_len: Length of data1 in bytes
+ * @data2: Optional data, second block; %NULL if not used
+ * @data2_len: Length of data2 in bytes
+ * @data3: Optional data, third block; %NULL if not used
+ * @data3_len: Length of data3 in bytes
+ * @mac: Buffer for the MAC value (EAP_PAX_MAC_LEN = 16 bytes)
+ * Returns: 0 on success, -1 on failure
+ *
+ * Wrapper function to calculate EAP-PAX MAC.
+ */
+int eap_pax_mac(u8 mac_id, const u8 *key, size_t key_len,
+ const u8 *data1, size_t data1_len,
+ const u8 *data2, size_t data2_len,
+ const u8 *data3, size_t data3_len,
+ u8 *mac)
+{
+ u8 hash[SHA1_MAC_LEN];
+ const u8 *addr[3];
+ size_t len[3];
+ size_t count;
+
+ /* TODO: add support for EAP_PAX_HMAC_SHA256_128 */
+ if (mac_id != EAP_PAX_MAC_HMAC_SHA1_128)
+ return -1;
+
+ addr[0] = data1;
+ len[0] = data1_len;
+ addr[1] = data2;
+ len[1] = data2_len;
+ addr[2] = data3;
+ len[2] = data3_len;
+
+ count = (data1 ? 1 : 0) + (data2 ? 1 : 0) + (data3 ? 1 : 0);
+ hmac_sha1_vector(key, key_len, count, addr, len, hash);
+ os_memcpy(mac, hash, EAP_PAX_MAC_LEN);
+
+ return 0;
+}
+
+
+/**
+ * eap_pax_initial_key_derivation - EAP-PAX initial key derivation
+ * @mac_id: MAC ID (EAP_PAX_MAC_*) / currently, only HMAC_SHA1_128 is supported
+ * @ak: Authentication Key
+ * @e: Entropy
+ * @mk: Buffer for the derived Master Key
+ * @ck: Buffer for the derived Confirmation Key
+ * @ick: Buffer for the derived Integrity Check Key
+ * Returns: 0 on success, -1 on failure
+ */
+int eap_pax_initial_key_derivation(u8 mac_id, const u8 *ak, const u8 *e,
+ u8 *mk, u8 *ck, u8 *ick)
+{
+ wpa_printf(MSG_DEBUG, "EAP-PAX: initial key derivation");
+ if (eap_pax_kdf(mac_id, ak, EAP_PAX_AK_LEN, "Master Key",
+ e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_MK_LEN, mk) ||
+ eap_pax_kdf(mac_id, mk, EAP_PAX_MK_LEN, "Confirmation Key",
+ e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_CK_LEN, ck) ||
+ eap_pax_kdf(mac_id, mk, EAP_PAX_MK_LEN, "Integrity Check Key",
+ e, 2 * EAP_PAX_RAND_LEN, EAP_PAX_ICK_LEN, ick))
+ return -1;
+
+ wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: AK", ak, EAP_PAX_AK_LEN);
+ wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: MK", mk, EAP_PAX_MK_LEN);
+ wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: CK", ck, EAP_PAX_CK_LEN);
+ wpa_hexdump_key(MSG_MSGDUMP, "EAP-PAX: ICK", ick, EAP_PAX_ICK_LEN);
+
+ return 0;
+}
projects / mech_eap.git / blobdiff