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 "crypto/tls.h"
14 #include "eap_defs.h"
15 #include "eap_tlv_common.h"
16 #include "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,const char * label,size_t len)96 u8 * eap_fast_derive_key(void *ssl_ctx, struct tls_connection *conn,
97 const char *label, size_t len)
98 {
99 u8 *out;
100
101 out = os_malloc(len);
102 if (out == NULL)
103 return NULL;
104
105 if (tls_connection_prf(ssl_ctx, conn, label, 1, 1, out, len)) {
106 os_free(out);
107 return NULL;
108 }
109
110 return out;
111 }
112
113
eap_fast_derive_eap_msk(const u8 * simck,u8 * msk)114 int eap_fast_derive_eap_msk(const u8 *simck, u8 *msk)
115 {
116 /*
117 * RFC 4851, Section 5.4: EAP Master Session Key Generation
118 * MSK = T-PRF(S-IMCK[j], "Session Key Generating Function", 64)
119 */
120
121 if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
122 "Session Key Generating Function", (u8 *) "", 0,
123 msk, EAP_FAST_KEY_LEN) < 0)
124 return -1;
125 wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (MSK)",
126 msk, EAP_FAST_KEY_LEN);
127 return 0;
128 }
129
130
eap_fast_derive_eap_emsk(const u8 * simck,u8 * emsk)131 int eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk)
132 {
133 /*
134 * RFC 4851, Section 5.4: EAP Master Session Key Genreration
135 * EMSK = T-PRF(S-IMCK[j],
136 * "Extended Session Key Generating Function", 64)
137 */
138
139 if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
140 "Extended Session Key Generating Function", (u8 *) "", 0,
141 emsk, EAP_EMSK_LEN) < 0)
142 return -1;
143 wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (EMSK)",
144 emsk, EAP_EMSK_LEN);
145 return 0;
146 }
147
148
eap_fast_parse_tlv(struct eap_fast_tlv_parse * tlv,int tlv_type,u8 * pos,size_t len)149 int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv,
150 int tlv_type, u8 *pos, size_t len)
151 {
152 switch (tlv_type) {
153 case EAP_TLV_EAP_PAYLOAD_TLV:
154 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: EAP-Payload TLV",
155 pos, len);
156 if (tlv->eap_payload_tlv) {
157 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
158 "EAP-Payload TLV in the message");
159 tlv->iresult = EAP_TLV_RESULT_FAILURE;
160 return -2;
161 }
162 tlv->eap_payload_tlv = pos;
163 tlv->eap_payload_tlv_len = len;
164 break;
165 case EAP_TLV_RESULT_TLV:
166 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Result TLV", pos, len);
167 if (tlv->result) {
168 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
169 "Result TLV in the message");
170 tlv->result = EAP_TLV_RESULT_FAILURE;
171 return -2;
172 }
173 if (len < 2) {
174 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
175 "Result TLV");
176 tlv->result = EAP_TLV_RESULT_FAILURE;
177 break;
178 }
179 tlv->result = WPA_GET_BE16(pos);
180 if (tlv->result != EAP_TLV_RESULT_SUCCESS &&
181 tlv->result != EAP_TLV_RESULT_FAILURE) {
182 wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Result %d",
183 tlv->result);
184 tlv->result = EAP_TLV_RESULT_FAILURE;
185 }
186 wpa_printf(MSG_DEBUG, "EAP-FAST: Result: %s",
187 tlv->result == EAP_TLV_RESULT_SUCCESS ?
188 "Success" : "Failure");
189 break;
190 case EAP_TLV_INTERMEDIATE_RESULT_TLV:
191 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Intermediate Result TLV",
192 pos, len);
193 if (len < 2) {
194 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
195 "Intermediate-Result TLV");
196 tlv->iresult = EAP_TLV_RESULT_FAILURE;
197 break;
198 }
199 if (tlv->iresult) {
200 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
201 "Intermediate-Result TLV in the message");
202 tlv->iresult = EAP_TLV_RESULT_FAILURE;
203 return -2;
204 }
205 tlv->iresult = WPA_GET_BE16(pos);
206 if (tlv->iresult != EAP_TLV_RESULT_SUCCESS &&
207 tlv->iresult != EAP_TLV_RESULT_FAILURE) {
208 wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Intermediate "
209 "Result %d", tlv->iresult);
210 tlv->iresult = EAP_TLV_RESULT_FAILURE;
211 }
212 wpa_printf(MSG_DEBUG, "EAP-FAST: Intermediate Result: %s",
213 tlv->iresult == EAP_TLV_RESULT_SUCCESS ?
214 "Success" : "Failure");
215 break;
216 case EAP_TLV_CRYPTO_BINDING_TLV:
217 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV",
218 pos, len);
219 if (tlv->crypto_binding) {
220 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
221 "Crypto-Binding TLV in the message");
222 tlv->iresult = EAP_TLV_RESULT_FAILURE;
223 return -2;
224 }
225 tlv->crypto_binding_len = sizeof(struct eap_tlv_hdr) + len;
226 if (tlv->crypto_binding_len < sizeof(*tlv->crypto_binding)) {
227 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
228 "Crypto-Binding TLV");
229 tlv->iresult = EAP_TLV_RESULT_FAILURE;
230 return -2;
231 }
232 tlv->crypto_binding = (struct eap_tlv_crypto_binding_tlv *)
233 (pos - sizeof(struct eap_tlv_hdr));
234 break;
235 case EAP_TLV_REQUEST_ACTION_TLV:
236 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Request-Action TLV",
237 pos, len);
238 if (tlv->request_action) {
239 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
240 "Request-Action TLV in the message");
241 tlv->iresult = EAP_TLV_RESULT_FAILURE;
242 return -2;
243 }
244 if (len < 2) {
245 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
246 "Request-Action TLV");
247 tlv->iresult = EAP_TLV_RESULT_FAILURE;
248 break;
249 }
250 tlv->request_action = WPA_GET_BE16(pos);
251 wpa_printf(MSG_DEBUG, "EAP-FAST: Request-Action: %d",
252 tlv->request_action);
253 break;
254 case EAP_TLV_PAC_TLV:
255 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: PAC TLV", pos, len);
256 if (tlv->pac) {
257 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
258 "PAC TLV in the message");
259 tlv->iresult = EAP_TLV_RESULT_FAILURE;
260 return -2;
261 }
262 tlv->pac = pos;
263 tlv->pac_len = len;
264 break;
265 default:
266 /* Unknown TLV */
267 return -1;
268 }
269
270 return 0;
271 }
272