1 /*
2 * Wi-Fi Protected Setup - attribute processing
3 * Copyright (c) 2008, Jouni Malinen <j@w1.fi>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Alternatively, this software may be distributed under the terms of BSD
10 * license.
11 *
12 * See README and COPYING for more details.
13 */
14
15 #include "includes.h"
16
17 #include "common.h"
18 #include "crypto/sha256.h"
19 #include "wps_i.h"
20
21
wps_process_authenticator(struct wps_data * wps,const u8 * authenticator,const struct wpabuf * msg)22 int wps_process_authenticator(struct wps_data *wps, const u8 *authenticator,
23 const struct wpabuf *msg)
24 {
25 u8 hash[SHA256_MAC_LEN];
26 const u8 *addr[2];
27 size_t len[2];
28
29 if (authenticator == NULL) {
30 wpa_printf(MSG_DEBUG, "WPS: No Authenticator attribute "
31 "included");
32 return -1;
33 }
34
35 if (wps->last_msg == NULL) {
36 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
37 "validating authenticator");
38 return -1;
39 }
40
41 /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
42 * (M_curr* is M_curr without the Authenticator attribute)
43 */
44 addr[0] = wpabuf_head(wps->last_msg);
45 len[0] = wpabuf_len(wps->last_msg);
46 addr[1] = wpabuf_head(msg);
47 len[1] = wpabuf_len(msg) - 4 - WPS_AUTHENTICATOR_LEN;
48 hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
49
50 if (os_memcmp(hash, authenticator, WPS_AUTHENTICATOR_LEN) != 0) {
51 wpa_printf(MSG_DEBUG, "WPS: Incorrect Authenticator");
52 return -1;
53 }
54
55 return 0;
56 }
57
58
wps_process_key_wrap_auth(struct wps_data * wps,struct wpabuf * msg,const u8 * key_wrap_auth)59 int wps_process_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg,
60 const u8 *key_wrap_auth)
61 {
62 u8 hash[SHA256_MAC_LEN];
63 const u8 *head;
64 size_t len;
65
66 if (key_wrap_auth == NULL) {
67 wpa_printf(MSG_DEBUG, "WPS: No KWA in decrypted attribute");
68 return -1;
69 }
70
71 head = wpabuf_head(msg);
72 len = wpabuf_len(msg) - 4 - WPS_KWA_LEN;
73 if (head + len != key_wrap_auth - 4) {
74 wpa_printf(MSG_DEBUG, "WPS: KWA not in the end of the "
75 "decrypted attribute");
76 return -1;
77 }
78
79 hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, head, len, hash);
80 if (os_memcmp(hash, key_wrap_auth, WPS_KWA_LEN) != 0) {
81 wpa_printf(MSG_DEBUG, "WPS: Invalid KWA");
82 return -1;
83 }
84
85 return 0;
86 }
87
88
wps_process_cred_network_idx(struct wps_credential * cred,const u8 * idx)89 static int wps_process_cred_network_idx(struct wps_credential *cred,
90 const u8 *idx)
91 {
92 if (idx == NULL) {
93 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
94 "Network Index");
95 return -1;
96 }
97
98 wpa_printf(MSG_DEBUG, "WPS: Network Index: %d", *idx);
99
100 return 0;
101 }
102
103
wps_process_cred_ssid(struct wps_credential * cred,const u8 * ssid,size_t ssid_len)104 static int wps_process_cred_ssid(struct wps_credential *cred, const u8 *ssid,
105 size_t ssid_len)
106 {
107 if (ssid == NULL) {
108 wpa_printf(MSG_DEBUG, "WPS: Credential did not include SSID");
109 return -1;
110 }
111
112 /* Remove zero-padding since some Registrar implementations seem to use
113 * hardcoded 32-octet length for this attribute */
114 while (ssid_len > 0 && ssid[ssid_len - 1] == 0)
115 ssid_len--;
116
117 wpa_hexdump_ascii(MSG_DEBUG, "WPS: SSID", ssid, ssid_len);
118 if (ssid_len <= sizeof(cred->ssid)) {
119 os_memcpy(cred->ssid, ssid, ssid_len);
120 cred->ssid_len = ssid_len;
121 }
122
123 return 0;
124 }
125
126
wps_process_cred_auth_type(struct wps_credential * cred,const u8 * auth_type)127 static int wps_process_cred_auth_type(struct wps_credential *cred,
128 const u8 *auth_type)
129 {
130 if (auth_type == NULL) {
131 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
132 "Authentication Type");
133 return -1;
134 }
135
136 cred->auth_type = WPA_GET_BE16(auth_type);
137 wpa_printf(MSG_DEBUG, "WPS: Authentication Type: 0x%x",
138 cred->auth_type);
139
140 return 0;
141 }
142
143
wps_process_cred_encr_type(struct wps_credential * cred,const u8 * encr_type)144 static int wps_process_cred_encr_type(struct wps_credential *cred,
145 const u8 *encr_type)
146 {
147 if (encr_type == NULL) {
148 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
149 "Encryption Type");
150 return -1;
151 }
152
153 cred->encr_type = WPA_GET_BE16(encr_type);
154 wpa_printf(MSG_DEBUG, "WPS: Encryption Type: 0x%x",
155 cred->encr_type);
156
157 return 0;
158 }
159
160
wps_process_cred_network_key_idx(struct wps_credential * cred,const u8 * key_idx)161 static int wps_process_cred_network_key_idx(struct wps_credential *cred,
162 const u8 *key_idx)
163 {
164 if (key_idx == NULL)
165 return 0; /* optional attribute */
166
167 wpa_printf(MSG_DEBUG, "WPS: Network Key Index: %d", *key_idx);
168 cred->key_idx = *key_idx;
169
170 return 0;
171 }
172
173
wps_process_cred_network_key(struct wps_credential * cred,const u8 * key,size_t key_len)174 static int wps_process_cred_network_key(struct wps_credential *cred,
175 const u8 *key, size_t key_len)
176 {
177 if (key == NULL) {
178 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
179 "Network Key");
180 return -1;
181 }
182
183 wpa_hexdump_key(MSG_DEBUG, "WPS: Network Key", key, key_len);
184 if (key_len <= sizeof(cred->key)) {
185 os_memcpy(cred->key, key, key_len);
186 cred->key_len = key_len;
187 }
188
189 return 0;
190 }
191
192
wps_process_cred_mac_addr(struct wps_credential * cred,const u8 * mac_addr)193 static int wps_process_cred_mac_addr(struct wps_credential *cred,
194 const u8 *mac_addr)
195 {
196 if (mac_addr == NULL) {
197 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
198 "MAC Address");
199 return -1;
200 }
201
202 wpa_printf(MSG_DEBUG, "WPS: MAC Address " MACSTR, MAC2STR(mac_addr));
203 os_memcpy(cred->mac_addr, mac_addr, ETH_ALEN);
204
205 return 0;
206 }
207
208
wps_process_cred_eap_type(struct wps_credential * cred,const u8 * eap_type,size_t eap_type_len)209 static int wps_process_cred_eap_type(struct wps_credential *cred,
210 const u8 *eap_type, size_t eap_type_len)
211 {
212 if (eap_type == NULL)
213 return 0; /* optional attribute */
214
215 wpa_hexdump(MSG_DEBUG, "WPS: EAP Type", eap_type, eap_type_len);
216
217 return 0;
218 }
219
220
wps_process_cred_eap_identity(struct wps_credential * cred,const u8 * identity,size_t identity_len)221 static int wps_process_cred_eap_identity(struct wps_credential *cred,
222 const u8 *identity,
223 size_t identity_len)
224 {
225 if (identity == NULL)
226 return 0; /* optional attribute */
227
228 wpa_hexdump_ascii(MSG_DEBUG, "WPS: EAP Identity",
229 identity, identity_len);
230
231 return 0;
232 }
233
234
wps_process_cred_key_prov_auto(struct wps_credential * cred,const u8 * key_prov_auto)235 static int wps_process_cred_key_prov_auto(struct wps_credential *cred,
236 const u8 *key_prov_auto)
237 {
238 if (key_prov_auto == NULL)
239 return 0; /* optional attribute */
240
241 wpa_printf(MSG_DEBUG, "WPS: Key Provided Automatically: %d",
242 *key_prov_auto);
243
244 return 0;
245 }
246
247
wps_process_cred_802_1x_enabled(struct wps_credential * cred,const u8 * dot1x_enabled)248 static int wps_process_cred_802_1x_enabled(struct wps_credential *cred,
249 const u8 *dot1x_enabled)
250 {
251 if (dot1x_enabled == NULL)
252 return 0; /* optional attribute */
253
254 wpa_printf(MSG_DEBUG, "WPS: 802.1X Enabled: %d", *dot1x_enabled);
255
256 return 0;
257 }
258
259
wps_workaround_cred_key(struct wps_credential * cred)260 static void wps_workaround_cred_key(struct wps_credential *cred)
261 {
262 if (cred->auth_type & (WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK) &&
263 cred->key_len > 8 && cred->key_len < 64 &&
264 cred->key[cred->key_len - 1] == 0) {
265 /*
266 * A deployed external registrar is known to encode ASCII
267 * passphrases incorrectly. Remove the extra NULL termination
268 * to fix the encoding.
269 */
270 wpa_printf(MSG_DEBUG, "WPS: Workaround - remove NULL "
271 "termination from ASCII passphrase");
272 cred->key_len--;
273 }
274 }
275
276
wps_process_cred(struct wps_parse_attr * attr,struct wps_credential * cred)277 int wps_process_cred(struct wps_parse_attr *attr,
278 struct wps_credential *cred)
279 {
280 wpa_printf(MSG_DEBUG, "WPS: Process Credential");
281
282 /* TODO: support multiple Network Keys */
283 if (wps_process_cred_network_idx(cred, attr->network_idx) ||
284 wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
285 wps_process_cred_auth_type(cred, attr->auth_type) ||
286 wps_process_cred_encr_type(cred, attr->encr_type) ||
287 wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
288 wps_process_cred_network_key(cred, attr->network_key,
289 attr->network_key_len) ||
290 wps_process_cred_mac_addr(cred, attr->mac_addr) ||
291 wps_process_cred_eap_type(cred, attr->eap_type,
292 attr->eap_type_len) ||
293 wps_process_cred_eap_identity(cred, attr->eap_identity,
294 attr->eap_identity_len) ||
295 wps_process_cred_key_prov_auto(cred, attr->key_prov_auto) ||
296 wps_process_cred_802_1x_enabled(cred, attr->dot1x_enabled))
297 return -1;
298
299 wps_workaround_cred_key(cred);
300
301 return 0;
302 }
303
304
wps_process_ap_settings(struct wps_parse_attr * attr,struct wps_credential * cred)305 int wps_process_ap_settings(struct wps_parse_attr *attr,
306 struct wps_credential *cred)
307 {
308 wpa_printf(MSG_DEBUG, "WPS: Processing AP Settings");
309 os_memset(cred, 0, sizeof(*cred));
310 /* TODO: optional attributes New Password and Device Password ID */
311 if (wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
312 wps_process_cred_auth_type(cred, attr->auth_type) ||
313 wps_process_cred_encr_type(cred, attr->encr_type) ||
314 wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
315 wps_process_cred_network_key(cred, attr->network_key,
316 attr->network_key_len) ||
317 wps_process_cred_mac_addr(cred, attr->mac_addr))
318 return -1;
319
320 wps_workaround_cred_key(cred);
321
322 return 0;
323 }
324