2 * IEEE 802.1X-2010 Key Hierarchy
3 * Copyright (c) 2013, Qualcomm Atheros, Inc.
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
8 * SAK derivation specified in IEEE Std 802.1X-2010, Clause 6.2
11 #include "utils/includes.h"
13 #include "utils/common.h"
14 #include "crypto/md5.h"
15 #include "crypto/sha1.h"
16 #include "crypto/aes_wrap.h"
17 #include "crypto/crypto.h"
18 #include "ieee802_1x_key.h"
21 static void joint_two_mac(const u8 *mac1, const u8 *mac2, u8 *out)
23 if (os_memcmp(mac1, mac2, ETH_ALEN) < 0) {
24 os_memcpy(out, mac1, ETH_ALEN);
25 os_memcpy(out + ETH_ALEN, mac2, ETH_ALEN);
27 os_memcpy(out, mac2, ETH_ALEN);
28 os_memcpy(out + ETH_ALEN, mac1, ETH_ALEN);
33 /* IEEE Std 802.1X-2010, 6.2.1 KDF */
34 static int aes_kdf_128(const u8 *kdk, const char *label, const u8 *context,
35 int ctx_bits, int ret_bits, u8 *ret)
40 int lab_len, ctx_len, ret_len, buf_len;
43 lab_len = os_strlen(label);
44 ctx_len = (ctx_bits + 7) / 8;
45 ret_len = ((ret_bits & 0xffff) + 7) / 8;
46 buf_len = lab_len + ctx_len + 4;
48 os_memset(ret, 0, ret_len);
50 n = (ret_bits + h - 1) / h;
51 if (n > ((0x1 << r) - 1))
54 buf = os_zalloc(buf_len);
58 os_memcpy(buf + 1, label, lab_len);
59 os_memcpy(buf + lab_len + 2, context, ctx_len);
60 WPA_PUT_BE16(&buf[buf_len - 2], ret_bits);
62 for (i = 0; i < n; i++) {
63 buf[0] = (u8) (i + 1);
64 if (omac1_aes_128(kdk, buf, buf_len, ret)) {
75 /********** AES-CMAC-128 **********/
77 * ieee802_1x_cak_128bits_aes_cmac
79 * IEEE Std 802.1X-2010, 6.2.2
80 * CAK = KDF(Key, Label, mac1 | mac2, CAKlength)
82 int ieee802_1x_cak_128bits_aes_cmac(const u8 *msk, const u8 *mac1,
83 const u8 *mac2, u8 *cak)
85 u8 context[2 * ETH_ALEN];
87 joint_two_mac(mac1, mac2, context);
88 return aes_kdf_128(msk, "IEEE8021 EAP CAK",
89 context, sizeof(context) * 8, 128, cak);
94 * ieee802_1x_ckn_128bits_aes_cmac
96 * IEEE Std 802.1X-2010, 6.2.2
97 * CKN = KDF(Key, Label, ID | mac1 | mac2, CKNlength)
99 int ieee802_1x_ckn_128bits_aes_cmac(const u8 *msk, const u8 *mac1,
100 const u8 *mac2, const u8 *sid,
101 size_t sid_bytes, u8 *ckn)
105 size_t ctx_len = sid_bytes + ETH_ALEN * 2;
107 context = os_zalloc(ctx_len);
109 wpa_printf(MSG_ERROR, "MKA-%s: out of memory", __func__);
112 os_memcpy(context, sid, sid_bytes);
113 joint_two_mac(mac1, mac2, context + sid_bytes);
115 res = aes_kdf_128(msk, "IEEE8021 EAP CKN", context, ctx_len * 8,
123 * ieee802_1x_kek_128bits_aes_cmac
125 * IEEE Std 802.1X-2010, 9.3.3
126 * KEK = KDF(Key, Label, Keyid, KEKLength)
128 int ieee802_1x_kek_128bits_aes_cmac(const u8 *cak, const u8 *ckn,
129 size_t ckn_bytes, u8 *kek)
133 /* First 16 octets of CKN, with null octets appended to pad if needed */
134 os_memset(context, 0, sizeof(context));
135 os_memcpy(context, ckn, (ckn_bytes < 16) ? ckn_bytes : 16);
137 return aes_kdf_128(cak, "IEEE8021 KEK", context, sizeof(context) * 8,
143 * ieee802_1x_ick_128bits_aes_cmac
145 * IEEE Std 802.1X-2010, 9.3.3
146 * ICK = KDF(Key, Label, Keyid, ICKLength)
148 int ieee802_1x_ick_128bits_aes_cmac(const u8 *cak, const u8 *ckn,
149 size_t ckn_bytes, u8 *ick)
153 /* First 16 octets of CKN, with null octets appended to pad if needed */
154 os_memset(context, 0, sizeof(context));
155 os_memcpy(context, ckn, (ckn_bytes < 16) ? ckn_bytes : 16);
157 return aes_kdf_128(cak, "IEEE8021 ICK", context, sizeof(context) * 8,
163 * ieee802_1x_icv_128bits_aes_cmac
165 * IEEE Std 802.1X-2010, 9.4.1
166 * ICV = AES-CMAC(ICK, M, 128)
168 int ieee802_1x_icv_128bits_aes_cmac(const u8 *ick, const u8 *msg,
169 size_t msg_bytes, u8 *icv)
171 if (omac1_aes_128(ick, msg, msg_bytes, icv)) {
172 wpa_printf(MSG_ERROR, "MKA: omac1_aes_128 failed");
180 * ieee802_1x_sak_128bits_aes_cmac
182 * IEEE Std 802.1X-2010, 9.8.1
183 * SAK = KDF(Key, Label, KS-nonce | MI-value list | KN, SAKLength)
185 int ieee802_1x_sak_128bits_aes_cmac(const u8 *cak, const u8 *ctx,
186 size_t ctx_bytes, u8 *sak)
188 return aes_kdf_128(cak, "IEEE8021 SAK", ctx, ctx_bytes * 8, 128, sak);