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