1 /*
2 * EAP-FAST common helper functions (RFC 4851)
3 * Copyright (c) 2008, 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/sha1.h"
13 #include "tls/tls.h"
14 #include "eap_peer/eap_defs.h"
15 #include "eap_peer/eap_tlv_common.h"
16 #include "eap_peer/eap_fast_common.h"
17
18
eap_fast_put_tlv_hdr(struct wpabuf * buf,u16 type,u16 len)19 void eap_fast_put_tlv_hdr(struct wpabuf *buf, u16 type, u16 len)
20 {
21 struct pac_tlv_hdr hdr;
22 hdr.type = host_to_be16(type);
23 hdr.len = host_to_be16(len);
24 wpabuf_put_data(buf, &hdr, sizeof(hdr));
25 }
26
27
eap_fast_put_tlv(struct wpabuf * buf,u16 type,const void * data,u16 len)28 void eap_fast_put_tlv(struct wpabuf *buf, u16 type, const void *data,
29 u16 len)
30 {
31 eap_fast_put_tlv_hdr(buf, type, len);
32 wpabuf_put_data(buf, data, len);
33 }
34
35
eap_fast_put_tlv_buf(struct wpabuf * buf,u16 type,const struct wpabuf * data)36 void eap_fast_put_tlv_buf(struct wpabuf *buf, u16 type,
37 const struct wpabuf *data)
38 {
39 eap_fast_put_tlv_hdr(buf, type, wpabuf_len(data));
40 wpabuf_put_buf(buf, data);
41 }
42
43
eap_fast_tlv_eap_payload(struct wpabuf * buf)44 struct wpabuf * eap_fast_tlv_eap_payload(struct wpabuf *buf)
45 {
46 struct wpabuf *e;
47
48 if (buf == NULL)
49 return NULL;
50
51 /* Encapsulate EAP packet in EAP-Payload TLV */
52 wpa_printf(MSG_DEBUG, "EAP-FAST: Add EAP-Payload TLV");
53 e = wpabuf_alloc(sizeof(struct pac_tlv_hdr) + wpabuf_len(buf));
54 if (e == NULL) {
55 wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to allocate memory "
56 "for TLV encapsulation");
57 wpabuf_free(buf);
58 return NULL;
59 }
60 eap_fast_put_tlv_buf(e,
61 EAP_TLV_TYPE_MANDATORY | EAP_TLV_EAP_PAYLOAD_TLV,
62 buf);
63 wpabuf_free(buf);
64 return e;
65 }
66
67
eap_fast_derive_master_secret(const u8 * pac_key,const u8 * server_random,const u8 * client_random,u8 * master_secret)68 void eap_fast_derive_master_secret(const u8 *pac_key, const u8 *server_random,
69 const u8 *client_random, u8 *master_secret)
70 {
71 #define TLS_RANDOM_LEN 32
72 #define TLS_MASTER_SECRET_LEN 48
73 u8 seed[2 * TLS_RANDOM_LEN];
74
75 wpa_hexdump(MSG_DEBUG, "EAP-FAST: client_random",
76 client_random, TLS_RANDOM_LEN);
77 wpa_hexdump(MSG_DEBUG, "EAP-FAST: server_random",
78 server_random, TLS_RANDOM_LEN);
79
80 /*
81 * RFC 4851, Section 5.1:
82 * master_secret = T-PRF(PAC-Key, "PAC to master secret label hash",
83 * server_random + client_random, 48)
84 */
85 os_memcpy(seed, server_random, TLS_RANDOM_LEN);
86 os_memcpy(seed + TLS_RANDOM_LEN, client_random, TLS_RANDOM_LEN);
87 sha1_t_prf(pac_key, EAP_FAST_PAC_KEY_LEN,
88 "PAC to master secret label hash",
89 seed, sizeof(seed), master_secret, TLS_MASTER_SECRET_LEN);
90
91 wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: master_secret",
92 master_secret, TLS_MASTER_SECRET_LEN);
93 }
94
95
eap_fast_derive_key(void * ssl_ctx,struct tls_connection * conn,size_t len)96 u8 * eap_fast_derive_key(void *ssl_ctx, struct tls_connection *conn, size_t len)
97 {
98 u8 *out;
99
100 out = os_malloc(len);
101 if (out == NULL)
102 return NULL;
103
104 if (tls_connection_get_eap_fast_key(ssl_ctx, conn, out, len)) {
105 os_free(out);
106 return NULL;
107 }
108
109 return out;
110 }
111
112
eap_fast_derive_eap_msk(const u8 * simck,u8 * msk)113 int eap_fast_derive_eap_msk(const u8 *simck, u8 *msk)
114 {
115 /*
116 * RFC 4851, Section 5.4: EAP Master Session Key Generation
117 * MSK = T-PRF(S-IMCK[j], "Session Key Generating Function", 64)
118 */
119
120 if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
121 "Session Key Generating Function", (u8 *) "", 0,
122 msk, EAP_FAST_KEY_LEN) < 0)
123 return -1;
124 wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (MSK)",
125 msk, EAP_FAST_KEY_LEN);
126 return 0;
127 }
128
129
eap_fast_derive_eap_emsk(const u8 * simck,u8 * emsk)130 int eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk)
131 {
132 /*
133 * RFC 4851, Section 5.4: EAP Master Session Key Genreration
134 * EMSK = T-PRF(S-IMCK[j],
135 * "Extended Session Key Generating Function", 64)
136 */
137
138 if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
139 "Extended Session Key Generating Function", (u8 *) "", 0,
140 emsk, EAP_EMSK_LEN) < 0)
141 return -1;
142 wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (EMSK)",
143 emsk, EAP_EMSK_LEN);
144 return 0;
145 }
146
147
eap_fast_parse_tlv(struct eap_fast_tlv_parse * tlv,int tlv_type,u8 * pos,size_t len)148 int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv,
149 int tlv_type, u8 *pos, size_t len)
150 {
151 switch (tlv_type) {
152 case EAP_TLV_EAP_PAYLOAD_TLV:
153 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: EAP-Payload TLV",
154 pos, len);
155 if (tlv->eap_payload_tlv) {
156 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
157 "EAP-Payload TLV in the message");
158 tlv->iresult = EAP_TLV_RESULT_FAILURE;
159 return -2;
160 }
161 tlv->eap_payload_tlv = pos;
162 tlv->eap_payload_tlv_len = len;
163 break;
164 case EAP_TLV_RESULT_TLV:
165 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Result TLV", pos, len);
166 if (tlv->result) {
167 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
168 "Result TLV in the message");
169 tlv->result = EAP_TLV_RESULT_FAILURE;
170 return -2;
171 }
172 if (len < 2) {
173 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
174 "Result TLV");
175 tlv->result = EAP_TLV_RESULT_FAILURE;
176 break;
177 }
178 tlv->result = WPA_GET_BE16(pos);
179 if (tlv->result != EAP_TLV_RESULT_SUCCESS &&
180 tlv->result != EAP_TLV_RESULT_FAILURE) {
181 wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Result %d",
182 tlv->result);
183 tlv->result = EAP_TLV_RESULT_FAILURE;
184 }
185 wpa_printf(MSG_DEBUG, "EAP-FAST: Result: %s",
186 tlv->result == EAP_TLV_RESULT_SUCCESS ?
187 "Success" : "Failure");
188 break;
189 case EAP_TLV_INTERMEDIATE_RESULT_TLV:
190 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Intermediate Result TLV",
191 pos, len);
192 if (len < 2) {
193 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
194 "Intermediate-Result TLV");
195 tlv->iresult = EAP_TLV_RESULT_FAILURE;
196 break;
197 }
198 if (tlv->iresult) {
199 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
200 "Intermediate-Result TLV in the message");
201 tlv->iresult = EAP_TLV_RESULT_FAILURE;
202 return -2;
203 }
204 tlv->iresult = WPA_GET_BE16(pos);
205 if (tlv->iresult != EAP_TLV_RESULT_SUCCESS &&
206 tlv->iresult != EAP_TLV_RESULT_FAILURE) {
207 wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Intermediate "
208 "Result %d", tlv->iresult);
209 tlv->iresult = EAP_TLV_RESULT_FAILURE;
210 }
211 wpa_printf(MSG_DEBUG, "EAP-FAST: Intermediate Result: %s",
212 tlv->iresult == EAP_TLV_RESULT_SUCCESS ?
213 "Success" : "Failure");
214 break;
215 case EAP_TLV_CRYPTO_BINDING_TLV:
216 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV",
217 pos, len);
218 if (tlv->crypto_binding) {
219 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
220 "Crypto-Binding TLV in the message");
221 tlv->iresult = EAP_TLV_RESULT_FAILURE;
222 return -2;
223 }
224 tlv->crypto_binding_len = sizeof(struct eap_tlv_hdr) + len;
225 if (tlv->crypto_binding_len < sizeof(*tlv->crypto_binding)) {
226 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
227 "Crypto-Binding TLV");
228 tlv->iresult = EAP_TLV_RESULT_FAILURE;
229 return -2;
230 }
231 tlv->crypto_binding = (struct eap_tlv_crypto_binding_tlv *)
232 (pos - sizeof(struct eap_tlv_hdr));
233 break;
234 case EAP_TLV_REQUEST_ACTION_TLV:
235 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Request-Action TLV",
236 pos, len);
237 if (tlv->request_action) {
238 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
239 "Request-Action TLV in the message");
240 tlv->iresult = EAP_TLV_RESULT_FAILURE;
241 return -2;
242 }
243 if (len < 2) {
244 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
245 "Request-Action TLV");
246 tlv->iresult = EAP_TLV_RESULT_FAILURE;
247 break;
248 }
249 tlv->request_action = WPA_GET_BE16(pos);
250 wpa_printf(MSG_DEBUG, "EAP-FAST: Request-Action: %d",
251 tlv->request_action);
252 break;
253 case EAP_TLV_PAC_TLV:
254 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: PAC TLV", pos, len);
255 if (tlv->pac) {
256 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
257 "PAC TLV in the message");
258 tlv->iresult = EAP_TLV_RESULT_FAILURE;
259 return -2;
260 }
261 tlv->pac = pos;
262 tlv->pac_len = len;
263 break;
264 default:
265 /* Unknown TLV */
266 return -1;
267 }
268
269 return 0;
270 }
271
