1 /*
2  * EAP-IKEv2 common routines
3  * Copyright (c) 2007, 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 "eap_defs.h"
13 #include "eap_common.h"
14 #include "ikev2_common.h"
15 #include "eap_ikev2_common.h"
16 
17 
18 int eap_ikev2_derive_keymat(int prf, struct ikev2_keys *keys,
19 			    const u8 *i_nonce, size_t i_nonce_len,
20 			    const u8 *r_nonce, size_t r_nonce_len,
21 			    u8 *keymat)
22 {
23 	u8 *nonces;
24 	size_t nlen;
25 
26 	/* KEYMAT = prf+(SK_d, Ni | Nr) */
27 	if (keys->SK_d == NULL || i_nonce == NULL || r_nonce == NULL)
28 		return -1;
29 
30 	nlen = i_nonce_len + r_nonce_len;
31 	nonces = os_malloc(nlen);
32 	if (nonces == NULL)
33 		return -1;
34 	os_memcpy(nonces, i_nonce, i_nonce_len);
35 	os_memcpy(nonces + i_nonce_len, r_nonce, r_nonce_len);
36 
37 	if (ikev2_prf_plus(prf, keys->SK_d, keys->SK_d_len, nonces, nlen,
38 			   keymat, EAP_MSK_LEN + EAP_EMSK_LEN)) {
39 		os_free(nonces);
40 		return -1;
41 	}
42 	os_free(nonces);
43 
44 	wpa_hexdump_key(MSG_DEBUG, "EAP-IKEV2: KEYMAT",
45 			keymat, EAP_MSK_LEN + EAP_EMSK_LEN);
46 
47 	return 0;
48 }
49 
50 
51 struct wpabuf * eap_ikev2_build_frag_ack(u8 id, u8 code)
52 {
53 	struct wpabuf *msg;
54 
55 	msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, 0, code, id);
56 	if (msg == NULL) {
57 		wpa_printf(MSG_ERROR, "EAP-IKEV2: Failed to allocate memory "
58 			   "for fragment ack");
59 		return NULL;
60 	}
61 
62 	wpa_printf(MSG_DEBUG, "EAP-IKEV2: Send fragment ack");
63 
64 	return msg;
65 }
66 
67 
68 int eap_ikev2_validate_icv(int integ_alg, struct ikev2_keys *keys,
69 			   int initiator, const struct wpabuf *msg,
70 			   const u8 *pos, const u8 *end)
71 {
72 	const struct ikev2_integ_alg *integ;
73 	size_t icv_len;
74 	u8 icv[IKEV2_MAX_HASH_LEN];
75 	const u8 *SK_a = initiator ? keys->SK_ai : keys->SK_ar;
76 
77 	integ = ikev2_get_integ(integ_alg);
78 	if (integ == NULL) {
79 		wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
80 			   "transform / cannot validate ICV");
81 		return -1;
82 	}
83 	icv_len = integ->hash_len;
84 
85 	if (end - pos < (int) icv_len) {
86 		wpa_printf(MSG_DEBUG, "EAP-IKEV2: Not enough room in the "
87 			   "message for Integrity Checksum Data");
88 		return -1;
89 	}
90 
91 	if (SK_a == NULL) {
92 		wpa_printf(MSG_DEBUG, "EAP-IKEV2: No SK_a for ICV validation");
93 		return -1;
94 	}
95 
96 	if (ikev2_integ_hash(integ_alg, SK_a, keys->SK_integ_len,
97 			     wpabuf_head(msg),
98 			     wpabuf_len(msg) - icv_len, icv) < 0) {
99 		wpa_printf(MSG_INFO, "EAP-IKEV2: Could not calculate ICV");
100 		return -1;
101 	}
102 
103 	if (os_memcmp_const(icv, end - icv_len, icv_len) != 0) {
104 		wpa_printf(MSG_INFO, "EAP-IKEV2: Invalid ICV");
105 		wpa_hexdump(MSG_DEBUG, "EAP-IKEV2: Calculated ICV",
106 			    icv, icv_len);
107 		wpa_hexdump(MSG_DEBUG, "EAP-IKEV2: Received ICV",
108 			    end - icv_len, icv_len);
109 		return -1;
110 	}
111 
112 	wpa_printf(MSG_DEBUG, "EAP-IKEV2: Valid Integrity Checksum Data in "
113 		   "the received message");
114 
115 	return icv_len;
116 }
117