1 /*
2 * EAP server/peer: EAP-PSK shared routines
3 * Copyright (c) 2004-2006, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #include "includes.h"
10
11 #include "common.h"
12 #include "crypto/aes_wrap.h"
13 #include "eap_defs.h"
14 #include "eap_psk_common.h"
15
16 #define aes_block_size 16
17
18
eap_psk_key_setup(const u8 * psk,u8 * ak,u8 * kdk)19 int eap_psk_key_setup(const u8 *psk, u8 *ak, u8 *kdk)
20 {
21 os_memset(ak, 0, aes_block_size);
22 if (aes_128_encrypt_block(psk, ak, ak))
23 return -1;
24 os_memcpy(kdk, ak, aes_block_size);
25 ak[aes_block_size - 1] ^= 0x01;
26 kdk[aes_block_size - 1] ^= 0x02;
27 if (aes_128_encrypt_block(psk, ak, ak) ||
28 aes_128_encrypt_block(psk, kdk, kdk))
29 return -1;
30 return 0;
31 }
32
33
eap_psk_derive_keys(const u8 * kdk,const u8 * rand_p,u8 * tek,u8 * msk,u8 * emsk)34 int eap_psk_derive_keys(const u8 *kdk, const u8 *rand_p, u8 *tek, u8 *msk,
35 u8 *emsk)
36 {
37 u8 hash[aes_block_size];
38 u8 counter = 1;
39 int i;
40
41 if (aes_128_encrypt_block(kdk, rand_p, hash))
42 return -1;
43
44 hash[aes_block_size - 1] ^= counter;
45 if (aes_128_encrypt_block(kdk, hash, tek))
46 return -1;
47 hash[aes_block_size - 1] ^= counter;
48 counter++;
49
50 for (i = 0; i < EAP_MSK_LEN / aes_block_size; i++) {
51 hash[aes_block_size - 1] ^= counter;
52 if (aes_128_encrypt_block(kdk, hash, &msk[i * aes_block_size]))
53 return -1;
54 hash[aes_block_size - 1] ^= counter;
55 counter++;
56 }
57
58 for (i = 0; i < EAP_EMSK_LEN / aes_block_size; i++) {
59 hash[aes_block_size - 1] ^= counter;
60 if (aes_128_encrypt_block(kdk, hash,
61 &emsk[i * aes_block_size]))
62 return -1;
63 hash[aes_block_size - 1] ^= counter;
64 counter++;
65 }
66
67 return 0;
68 }
69
