1 /*
2 * Wi-Fi Protected Setup - attribute processing
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/sha256.h"
13 #include "wps_i.h"
14
15
wps_process_authenticator(struct wps_data * wps,const u8 * authenticator,const struct wpabuf * msg)16 int wps_process_authenticator(struct wps_data *wps, const u8 *authenticator,
17 const struct wpabuf *msg)
18 {
19 u8 hash[SHA256_MAC_LEN];
20 const u8 *addr[2];
21 size_t len[2];
22
23 if (authenticator == NULL) {
24 wpa_printf(MSG_DEBUG, "WPS: No Authenticator attribute "
25 "included");
26 return -1;
27 }
28
29 if (wps->last_msg == NULL) {
30 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
31 "validating authenticator");
32 return -1;
33 }
34
35 /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
36 * (M_curr* is M_curr without the Authenticator attribute)
37 */
38 addr[0] = wpabuf_head(wps->last_msg);
39 len[0] = wpabuf_len(wps->last_msg);
40 addr[1] = wpabuf_head(msg);
41 len[1] = wpabuf_len(msg) - 4 - WPS_AUTHENTICATOR_LEN;
42 hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
43
44 if (os_memcmp(hash, authenticator, WPS_AUTHENTICATOR_LEN) != 0) {
45 wpa_printf(MSG_DEBUG, "WPS: Incorrect Authenticator");
46 return -1;
47 }
48
49 return 0;
50 }
51
52
wps_process_key_wrap_auth(struct wps_data * wps,struct wpabuf * msg,const u8 * key_wrap_auth)53 int wps_process_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg,
54 const u8 *key_wrap_auth)
55 {
56 u8 hash[SHA256_MAC_LEN];
57 const u8 *head;
58 size_t len;
59
60 if (key_wrap_auth == NULL) {
61 wpa_printf(MSG_DEBUG, "WPS: No KWA in decrypted attribute");
62 return -1;
63 }
64
65 head = wpabuf_head(msg);
66 len = wpabuf_len(msg) - 4 - WPS_KWA_LEN;
67 if (head + len != key_wrap_auth - 4) {
68 wpa_printf(MSG_DEBUG, "WPS: KWA not in the end of the "
69 "decrypted attribute");
70 return -1;
71 }
72
73 hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, head, len, hash);
74 if (os_memcmp(hash, key_wrap_auth, WPS_KWA_LEN) != 0) {
75 wpa_printf(MSG_DEBUG, "WPS: Invalid KWA");
76 return -1;
77 }
78
79 return 0;
80 }
81
82
wps_process_cred_network_idx(struct wps_credential * cred,const u8 * idx)83 static int wps_process_cred_network_idx(struct wps_credential *cred,
84 const u8 *idx)
85 {
86 if (idx == NULL) {
87 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
88 "Network Index");
89 return -1;
90 }
91
92 wpa_printf(MSG_DEBUG, "WPS: Network Index: %d", *idx);
93
94 return 0;
95 }
96
97
wps_process_cred_ssid(struct wps_credential * cred,const u8 * ssid,size_t ssid_len)98 static int wps_process_cred_ssid(struct wps_credential *cred, const u8 *ssid,
99 size_t ssid_len)
100 {
101 if (ssid == NULL) {
102 wpa_printf(MSG_DEBUG, "WPS: Credential did not include SSID");
103 return -1;
104 }
105
106 /* Remove zero-padding since some Registrar implementations seem to use
107 * hardcoded 32-octet length for this attribute */
108 while (ssid_len > 0 && ssid[ssid_len - 1] == 0)
109 ssid_len--;
110
111 wpa_hexdump_ascii(MSG_DEBUG, "WPS: SSID", ssid, ssid_len);
112 if (ssid_len <= sizeof(cred->ssid)) {
113 os_memcpy(cred->ssid, ssid, ssid_len);
114 cred->ssid_len = ssid_len;
115 }
116
117 return 0;
118 }
119
120
wps_process_cred_auth_type(struct wps_credential * cred,const u8 * auth_type)121 static int wps_process_cred_auth_type(struct wps_credential *cred,
122 const u8 *auth_type)
123 {
124 if (auth_type == NULL) {
125 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
126 "Authentication Type");
127 return -1;
128 }
129
130 cred->auth_type = WPA_GET_BE16(auth_type);
131 wpa_printf(MSG_DEBUG, "WPS: Authentication Type: 0x%x",
132 cred->auth_type);
133
134 return 0;
135 }
136
137
wps_process_cred_encr_type(struct wps_credential * cred,const u8 * encr_type)138 static int wps_process_cred_encr_type(struct wps_credential *cred,
139 const u8 *encr_type)
140 {
141 if (encr_type == NULL) {
142 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
143 "Encryption Type");
144 return -1;
145 }
146
147 cred->encr_type = WPA_GET_BE16(encr_type);
148 wpa_printf(MSG_DEBUG, "WPS: Encryption Type: 0x%x",
149 cred->encr_type);
150
151 return 0;
152 }
153
154
wps_process_cred_network_key_idx(struct wps_credential * cred,const u8 * key_idx)155 static int wps_process_cred_network_key_idx(struct wps_credential *cred,
156 const u8 *key_idx)
157 {
158 if (key_idx == NULL)
159 return 0; /* optional attribute */
160
161 wpa_printf(MSG_DEBUG, "WPS: Network Key Index: %d", *key_idx);
162 cred->key_idx = *key_idx;
163
164 return 0;
165 }
166
167
wps_process_cred_network_key(struct wps_credential * cred,const u8 * key,size_t key_len)168 static int wps_process_cred_network_key(struct wps_credential *cred,
169 const u8 *key, size_t key_len)
170 {
171 if (key == NULL) {
172 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
173 "Network Key");
174 if (cred->auth_type == WPS_AUTH_OPEN &&
175 cred->encr_type == WPS_ENCR_NONE) {
176 wpa_printf(MSG_DEBUG, "WPS: Workaround - Allow "
177 "missing mandatory Network Key attribute "
178 "for open network");
179 return 0;
180 }
181 return -1;
182 }
183
184 wpa_hexdump_key(MSG_DEBUG, "WPS: Network Key", key, key_len);
185 if (key_len <= sizeof(cred->key)) {
186 os_memcpy(cred->key, key, key_len);
187 cred->key_len = key_len;
188 }
189
190 return 0;
191 }
192
193
wps_process_cred_mac_addr(struct wps_credential * cred,const u8 * mac_addr)194 static int wps_process_cred_mac_addr(struct wps_credential *cred,
195 const u8 *mac_addr)
196 {
197 if (mac_addr == NULL) {
198 wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
199 "MAC Address");
200 return -1;
201 }
202
203 wpa_printf(MSG_DEBUG, "WPS: MAC Address " MACSTR, MAC2STR(mac_addr));
204 os_memcpy(cred->mac_addr, mac_addr, ETH_ALEN);
205
206 return 0;
207 }
208
209
wps_process_cred_eap_type(struct wps_credential * cred,const u8 * eap_type,size_t eap_type_len)210 static int wps_process_cred_eap_type(struct wps_credential *cred,
211 const u8 *eap_type, size_t eap_type_len)
212 {
213 if (eap_type == NULL)
214 return 0; /* optional attribute */
215
216 wpa_hexdump(MSG_DEBUG, "WPS: EAP Type", eap_type, eap_type_len);
217
218 return 0;
219 }
220
221
wps_process_cred_eap_identity(struct wps_credential * cred,const u8 * identity,size_t identity_len)222 static int wps_process_cred_eap_identity(struct wps_credential *cred,
223 const u8 *identity,
224 size_t identity_len)
225 {
226 if (identity == NULL)
227 return 0; /* optional attribute */
228
229 wpa_hexdump_ascii(MSG_DEBUG, "WPS: EAP Identity",
230 identity, identity_len);
231
232 return 0;
233 }
234
235
wps_process_cred_key_prov_auto(struct wps_credential * cred,const u8 * key_prov_auto)236 static int wps_process_cred_key_prov_auto(struct wps_credential *cred,
237 const u8 *key_prov_auto)
238 {
239 if (key_prov_auto == NULL)
240 return 0; /* optional attribute */
241
242 wpa_printf(MSG_DEBUG, "WPS: Key Provided Automatically: %d",
243 *key_prov_auto);
244
245 return 0;
246 }
247
248
wps_process_cred_802_1x_enabled(struct wps_credential * cred,const u8 * dot1x_enabled)249 static int wps_process_cred_802_1x_enabled(struct wps_credential *cred,
250 const u8 *dot1x_enabled)
251 {
252 if (dot1x_enabled == NULL)
253 return 0; /* optional attribute */
254
255 wpa_printf(MSG_DEBUG, "WPS: 802.1X Enabled: %d", *dot1x_enabled);
256
257 return 0;
258 }
259
260
wps_process_cred_ap_channel(struct wps_credential * cred,const u8 * ap_channel)261 static int wps_process_cred_ap_channel(struct wps_credential *cred,
262 const u8 *ap_channel)
263 {
264 if (ap_channel == NULL)
265 return 0; /* optional attribute */
266
267 cred->ap_channel = WPA_GET_BE16(ap_channel);
268 wpa_printf(MSG_DEBUG, "WPS: AP Channel: %u", cred->ap_channel);
269
270 return 0;
271 }
272
273
wps_workaround_cred_key(struct wps_credential * cred)274 static int wps_workaround_cred_key(struct wps_credential *cred)
275 {
276 if (cred->auth_type & (WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK) &&
277 cred->key_len > 8 && cred->key_len < 64 &&
278 cred->key[cred->key_len - 1] == 0) {
279 #ifdef CONFIG_WPS_STRICT
280 wpa_printf(MSG_INFO, "WPS: WPA/WPA2-Personal passphrase uses "
281 "forbidden NULL termination");
282 wpa_hexdump_ascii_key(MSG_INFO, "WPS: Network Key",
283 cred->key, cred->key_len);
284 return -1;
285 #else /* CONFIG_WPS_STRICT */
286 /*
287 * A deployed external registrar is known to encode ASCII
288 * passphrases incorrectly. Remove the extra NULL termination
289 * to fix the encoding.
290 */
291 wpa_printf(MSG_DEBUG, "WPS: Workaround - remove NULL "
292 "termination from ASCII passphrase");
293 cred->key_len--;
294 #endif /* CONFIG_WPS_STRICT */
295 }
296 return 0;
297 }
298
299
wps_process_cred(struct wps_parse_attr * attr,struct wps_credential * cred)300 int wps_process_cred(struct wps_parse_attr *attr,
301 struct wps_credential *cred)
302 {
303 wpa_printf(MSG_DEBUG, "WPS: Process Credential");
304
305 /* TODO: support multiple Network Keys */
306 if (wps_process_cred_network_idx(cred, attr->network_idx) ||
307 wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
308 wps_process_cred_auth_type(cred, attr->auth_type) ||
309 wps_process_cred_encr_type(cred, attr->encr_type) ||
310 wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
311 wps_process_cred_network_key(cred, attr->network_key,
312 attr->network_key_len) ||
313 wps_process_cred_mac_addr(cred, attr->mac_addr) ||
314 wps_process_cred_eap_type(cred, attr->eap_type,
315 attr->eap_type_len) ||
316 wps_process_cred_eap_identity(cred, attr->eap_identity,
317 attr->eap_identity_len) ||
318 wps_process_cred_key_prov_auto(cred, attr->key_prov_auto) ||
319 wps_process_cred_802_1x_enabled(cred, attr->dot1x_enabled) ||
320 wps_process_cred_ap_channel(cred, attr->ap_channel))
321 return -1;
322
323 return wps_workaround_cred_key(cred);
324 }
325
326
wps_process_ap_settings(struct wps_parse_attr * attr,struct wps_credential * cred)327 int wps_process_ap_settings(struct wps_parse_attr *attr,
328 struct wps_credential *cred)
329 {
330 wpa_printf(MSG_DEBUG, "WPS: Processing AP Settings");
331 os_memset(cred, 0, sizeof(*cred));
332 /* TODO: optional attributes New Password and Device Password ID */
333 if (wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
334 wps_process_cred_auth_type(cred, attr->auth_type) ||
335 wps_process_cred_encr_type(cred, attr->encr_type) ||
336 wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
337 wps_process_cred_network_key(cred, attr->network_key,
338 attr->network_key_len) ||
339 wps_process_cred_mac_addr(cred, attr->mac_addr))
340 return -1;
341
342 return wps_workaround_cred_key(cred);
343 }
344