Line data Source code
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 :
16 1646 : 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 1646 : if (authenticator == NULL) {
24 0 : wpa_printf(MSG_DEBUG, "WPS: No Authenticator attribute "
25 : "included");
26 0 : return -1;
27 : }
28 :
29 1646 : if (wps->last_msg == NULL) {
30 0 : wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
31 : "validating authenticator");
32 0 : 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 1646 : addr[0] = wpabuf_head(wps->last_msg);
39 1646 : len[0] = wpabuf_len(wps->last_msg);
40 1646 : addr[1] = wpabuf_head(msg);
41 1646 : len[1] = wpabuf_len(msg) - 4 - WPS_AUTHENTICATOR_LEN;
42 1646 : hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
43 :
44 1646 : if (os_memcmp_const(hash, authenticator, WPS_AUTHENTICATOR_LEN) != 0) {
45 0 : wpa_printf(MSG_DEBUG, "WPS: Incorrect Authenticator");
46 0 : return -1;
47 : }
48 :
49 1646 : return 0;
50 : }
51 :
52 :
53 1160 : 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 1160 : if (key_wrap_auth == NULL) {
61 0 : wpa_printf(MSG_DEBUG, "WPS: No KWA in decrypted attribute");
62 0 : return -1;
63 : }
64 :
65 1160 : head = wpabuf_head(msg);
66 1160 : len = wpabuf_len(msg) - 4 - WPS_KWA_LEN;
67 1160 : if (head + len != key_wrap_auth - 4) {
68 0 : wpa_printf(MSG_DEBUG, "WPS: KWA not in the end of the "
69 : "decrypted attribute");
70 0 : return -1;
71 : }
72 :
73 1160 : hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, head, len, hash);
74 1160 : if (os_memcmp_const(hash, key_wrap_auth, WPS_KWA_LEN) != 0) {
75 0 : wpa_printf(MSG_DEBUG, "WPS: Invalid KWA");
76 0 : return -1;
77 : }
78 :
79 1160 : return 0;
80 : }
81 :
82 :
83 222 : static int wps_process_cred_network_idx(struct wps_credential *cred,
84 : const u8 *idx)
85 : {
86 222 : if (idx == NULL) {
87 2 : wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
88 : "Network Index");
89 2 : return -1;
90 : }
91 :
92 220 : wpa_printf(MSG_DEBUG, "WPS: Network Index: %d", *idx);
93 :
94 220 : return 0;
95 : }
96 :
97 :
98 256 : static int wps_process_cred_ssid(struct wps_credential *cred, const u8 *ssid,
99 : size_t ssid_len)
100 : {
101 256 : if (ssid == NULL) {
102 0 : wpa_printf(MSG_DEBUG, "WPS: Credential did not include SSID");
103 0 : return -1;
104 : }
105 :
106 : /* Remove zero-padding since some Registrar implementations seem to use
107 : * hardcoded 32-octet length for this attribute */
108 512 : while (ssid_len > 0 && ssid[ssid_len - 1] == 0)
109 0 : ssid_len--;
110 :
111 256 : wpa_hexdump_ascii(MSG_DEBUG, "WPS: SSID", ssid, ssid_len);
112 256 : if (ssid_len <= sizeof(cred->ssid)) {
113 256 : os_memcpy(cred->ssid, ssid, ssid_len);
114 256 : cred->ssid_len = ssid_len;
115 : }
116 :
117 256 : return 0;
118 : }
119 :
120 :
121 256 : static int wps_process_cred_auth_type(struct wps_credential *cred,
122 : const u8 *auth_type)
123 : {
124 256 : if (auth_type == NULL) {
125 0 : wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
126 : "Authentication Type");
127 0 : return -1;
128 : }
129 :
130 256 : cred->auth_type = WPA_GET_BE16(auth_type);
131 256 : wpa_printf(MSG_DEBUG, "WPS: Authentication Type: 0x%x",
132 256 : cred->auth_type);
133 :
134 256 : return 0;
135 : }
136 :
137 :
138 256 : static int wps_process_cred_encr_type(struct wps_credential *cred,
139 : const u8 *encr_type)
140 : {
141 256 : if (encr_type == NULL) {
142 0 : wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
143 : "Encryption Type");
144 0 : return -1;
145 : }
146 :
147 256 : cred->encr_type = WPA_GET_BE16(encr_type);
148 256 : wpa_printf(MSG_DEBUG, "WPS: Encryption Type: 0x%x",
149 256 : cred->encr_type);
150 :
151 256 : return 0;
152 : }
153 :
154 :
155 256 : static int wps_process_cred_network_key_idx(struct wps_credential *cred,
156 : const u8 *key_idx)
157 : {
158 256 : if (key_idx == NULL)
159 253 : return 0; /* optional attribute */
160 :
161 3 : wpa_printf(MSG_DEBUG, "WPS: Network Key Index: %d", *key_idx);
162 3 : cred->key_idx = *key_idx;
163 :
164 3 : return 0;
165 : }
166 :
167 :
168 256 : static int wps_process_cred_network_key(struct wps_credential *cred,
169 : const u8 *key, size_t key_len)
170 : {
171 256 : if (key == NULL) {
172 0 : wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
173 : "Network Key");
174 0 : if (cred->auth_type == WPS_AUTH_OPEN &&
175 0 : cred->encr_type == WPS_ENCR_NONE) {
176 0 : wpa_printf(MSG_DEBUG, "WPS: Workaround - Allow "
177 : "missing mandatory Network Key attribute "
178 : "for open network");
179 0 : return 0;
180 : }
181 0 : return -1;
182 : }
183 :
184 256 : wpa_hexdump_key(MSG_DEBUG, "WPS: Network Key", key, key_len);
185 256 : if (key_len <= sizeof(cred->key)) {
186 256 : os_memcpy(cred->key, key, key_len);
187 256 : cred->key_len = key_len;
188 : }
189 :
190 256 : return 0;
191 : }
192 :
193 :
194 256 : static int wps_process_cred_mac_addr(struct wps_credential *cred,
195 : const u8 *mac_addr)
196 : {
197 256 : if (mac_addr == NULL) {
198 0 : wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
199 : "MAC Address");
200 0 : return -1;
201 : }
202 :
203 256 : wpa_printf(MSG_DEBUG, "WPS: MAC Address " MACSTR, MAC2STR(mac_addr));
204 256 : os_memcpy(cred->mac_addr, mac_addr, ETH_ALEN);
205 :
206 256 : return 0;
207 : }
208 :
209 :
210 256 : static int wps_workaround_cred_key(struct wps_credential *cred)
211 : {
212 503 : if (cred->auth_type & (WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK) &&
213 456 : cred->key_len > 8 && cred->key_len < 64 &&
214 19 : cred->key[cred->key_len - 1] == 0) {
215 : #ifdef CONFIG_WPS_STRICT
216 : wpa_printf(MSG_INFO, "WPS: WPA/WPA2-Personal passphrase uses "
217 : "forbidden NULL termination");
218 : wpa_hexdump_ascii_key(MSG_INFO, "WPS: Network Key",
219 : cred->key, cred->key_len);
220 : return -1;
221 : #else /* CONFIG_WPS_STRICT */
222 : /*
223 : * A deployed external registrar is known to encode ASCII
224 : * passphrases incorrectly. Remove the extra NULL termination
225 : * to fix the encoding.
226 : */
227 0 : wpa_printf(MSG_DEBUG, "WPS: Workaround - remove NULL "
228 : "termination from ASCII passphrase");
229 0 : cred->key_len--;
230 : #endif /* CONFIG_WPS_STRICT */
231 : }
232 256 : return 0;
233 : }
234 :
235 :
236 222 : int wps_process_cred(struct wps_parse_attr *attr,
237 : struct wps_credential *cred)
238 : {
239 222 : wpa_printf(MSG_DEBUG, "WPS: Process Credential");
240 :
241 : /* TODO: support multiple Network Keys */
242 442 : if (wps_process_cred_network_idx(cred, attr->network_idx) ||
243 440 : wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
244 440 : wps_process_cred_auth_type(cred, attr->auth_type) ||
245 440 : wps_process_cred_encr_type(cred, attr->encr_type) ||
246 440 : wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
247 220 : wps_process_cred_network_key(cred, attr->network_key,
248 220 : attr->network_key_len) ||
249 220 : wps_process_cred_mac_addr(cred, attr->mac_addr))
250 2 : return -1;
251 :
252 220 : return wps_workaround_cred_key(cred);
253 : }
254 :
255 :
256 36 : int wps_process_ap_settings(struct wps_parse_attr *attr,
257 : struct wps_credential *cred)
258 : {
259 36 : wpa_printf(MSG_DEBUG, "WPS: Processing AP Settings");
260 36 : os_memset(cred, 0, sizeof(*cred));
261 : /* TODO: optional attributes New Password and Device Password ID */
262 72 : if (wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
263 72 : wps_process_cred_auth_type(cred, attr->auth_type) ||
264 72 : wps_process_cred_encr_type(cred, attr->encr_type) ||
265 72 : wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
266 36 : wps_process_cred_network_key(cred, attr->network_key,
267 36 : attr->network_key_len) ||
268 36 : wps_process_cred_mac_addr(cred, attr->mac_addr))
269 0 : return -1;
270 :
271 36 : return wps_workaround_cred_key(cred);
272 : }
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