1 /*
2 * Wi-Fi Protected Setup - attribute building
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/dh_groups.h"
19 #include "crypto/sha256.h"
20 #include "crypto/aes_wrap.h"
21 #include "wps_i.h"
22
23
wps_build_public_key(struct wps_data * wps,struct wpabuf * msg)24 int wps_build_public_key(struct wps_data *wps, struct wpabuf *msg)
25 {
26 struct wpabuf *pubkey;
27
28 wpa_printf(MSG_DEBUG, "WPS: * Public Key");
29 pubkey = dh_init(dh_groups_get(WPS_DH_GROUP), &wps->dh_privkey);
30 pubkey = wpabuf_zeropad(pubkey, 192);
31 if (pubkey == NULL) {
32 wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
33 "Diffie-Hellman handshake");
34 return -1;
35 }
36
37 wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
38 wpabuf_put_be16(msg, wpabuf_len(pubkey));
39 wpabuf_put_buf(msg, pubkey);
40
41 if (wps->registrar) {
42 wpabuf_free(wps->dh_pubkey_r);
43 wps->dh_pubkey_r = pubkey;
44 } else {
45 wpabuf_free(wps->dh_pubkey_e);
46 wps->dh_pubkey_e = pubkey;
47 }
48
49 return 0;
50 }
51
52
wps_build_req_type(struct wpabuf * msg,enum wps_request_type type)53 int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
54 {
55 wpa_printf(MSG_DEBUG, "WPS: * Request Type");
56 wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
57 wpabuf_put_be16(msg, 1);
58 wpabuf_put_u8(msg, type);
59 return 0;
60 }
61
62
wps_build_config_methods(struct wpabuf * msg,u16 methods)63 int wps_build_config_methods(struct wpabuf *msg, u16 methods)
64 {
65 wpa_printf(MSG_DEBUG, "WPS: * Config Methods (%x)", methods);
66 wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
67 wpabuf_put_be16(msg, 2);
68 wpabuf_put_be16(msg, methods);
69 return 0;
70 }
71
72
wps_build_uuid_e(struct wpabuf * msg,const u8 * uuid)73 int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
74 {
75 wpa_printf(MSG_DEBUG, "WPS: * UUID-E");
76 wpabuf_put_be16(msg, ATTR_UUID_E);
77 wpabuf_put_be16(msg, WPS_UUID_LEN);
78 wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
79 return 0;
80 }
81
82
wps_build_dev_password_id(struct wpabuf * msg,u16 id)83 int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
84 {
85 wpa_printf(MSG_DEBUG, "WPS: * Device Password ID (%d)", id);
86 wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
87 wpabuf_put_be16(msg, 2);
88 wpabuf_put_be16(msg, id);
89 return 0;
90 }
91
92
wps_build_config_error(struct wpabuf * msg,u16 err)93 int wps_build_config_error(struct wpabuf *msg, u16 err)
94 {
95 wpa_printf(MSG_DEBUG, "WPS: * Configuration Error (%d)", err);
96 wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
97 wpabuf_put_be16(msg, 2);
98 wpabuf_put_be16(msg, err);
99 return 0;
100 }
101
102
wps_build_authenticator(struct wps_data * wps,struct wpabuf * msg)103 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
104 {
105 u8 hash[SHA256_MAC_LEN];
106 const u8 *addr[2];
107 size_t len[2];
108
109 if (wps->last_msg == NULL) {
110 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
111 "building authenticator");
112 return -1;
113 }
114
115 /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
116 * (M_curr* is M_curr without the Authenticator attribute)
117 */
118 addr[0] = wpabuf_head(wps->last_msg);
119 len[0] = wpabuf_len(wps->last_msg);
120 addr[1] = wpabuf_head(msg);
121 len[1] = wpabuf_len(msg);
122 hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
123
124 wpa_printf(MSG_DEBUG, "WPS: * Authenticator");
125 wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
126 wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
127 wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
128
129 return 0;
130 }
131
132
wps_build_version(struct wpabuf * msg)133 int wps_build_version(struct wpabuf *msg)
134 {
135 wpa_printf(MSG_DEBUG, "WPS: * Version");
136 wpabuf_put_be16(msg, ATTR_VERSION);
137 wpabuf_put_be16(msg, 1);
138 wpabuf_put_u8(msg, WPS_VERSION);
139 return 0;
140 }
141
142
wps_build_msg_type(struct wpabuf * msg,enum wps_msg_type msg_type)143 int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
144 {
145 wpa_printf(MSG_DEBUG, "WPS: * Message Type (%d)", msg_type);
146 wpabuf_put_be16(msg, ATTR_MSG_TYPE);
147 wpabuf_put_be16(msg, 1);
148 wpabuf_put_u8(msg, msg_type);
149 return 0;
150 }
151
152
wps_build_enrollee_nonce(struct wps_data * wps,struct wpabuf * msg)153 int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
154 {
155 wpa_printf(MSG_DEBUG, "WPS: * Enrollee Nonce");
156 wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
157 wpabuf_put_be16(msg, WPS_NONCE_LEN);
158 wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
159 return 0;
160 }
161
162
wps_build_registrar_nonce(struct wps_data * wps,struct wpabuf * msg)163 int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
164 {
165 wpa_printf(MSG_DEBUG, "WPS: * Registrar Nonce");
166 wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
167 wpabuf_put_be16(msg, WPS_NONCE_LEN);
168 wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
169 return 0;
170 }
171
172
wps_build_auth_type_flags(struct wps_data * wps,struct wpabuf * msg)173 int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
174 {
175 wpa_printf(MSG_DEBUG, "WPS: * Authentication Type Flags");
176 wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
177 wpabuf_put_be16(msg, 2);
178 wpabuf_put_be16(msg, WPS_AUTH_TYPES);
179 return 0;
180 }
181
182
wps_build_encr_type_flags(struct wps_data * wps,struct wpabuf * msg)183 int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
184 {
185 wpa_printf(MSG_DEBUG, "WPS: * Encryption Type Flags");
186 wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
187 wpabuf_put_be16(msg, 2);
188 wpabuf_put_be16(msg, WPS_ENCR_TYPES);
189 return 0;
190 }
191
192
wps_build_conn_type_flags(struct wps_data * wps,struct wpabuf * msg)193 int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
194 {
195 wpa_printf(MSG_DEBUG, "WPS: * Connection Type Flags");
196 wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
197 wpabuf_put_be16(msg, 1);
198 wpabuf_put_u8(msg, WPS_CONN_ESS);
199 return 0;
200 }
201
202
wps_build_assoc_state(struct wps_data * wps,struct wpabuf * msg)203 int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
204 {
205 wpa_printf(MSG_DEBUG, "WPS: * Association State");
206 wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
207 wpabuf_put_be16(msg, 2);
208 wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
209 return 0;
210 }
211
212
wps_build_key_wrap_auth(struct wps_data * wps,struct wpabuf * msg)213 int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
214 {
215 u8 hash[SHA256_MAC_LEN];
216
217 wpa_printf(MSG_DEBUG, "WPS: * Key Wrap Authenticator");
218 hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
219 wpabuf_len(msg), hash);
220
221 wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
222 wpabuf_put_be16(msg, WPS_KWA_LEN);
223 wpabuf_put_data(msg, hash, WPS_KWA_LEN);
224 return 0;
225 }
226
227
wps_build_encr_settings(struct wps_data * wps,struct wpabuf * msg,struct wpabuf * plain)228 int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
229 struct wpabuf *plain)
230 {
231 size_t pad_len;
232 const size_t block_size = 16;
233 u8 *iv, *data;
234
235 wpa_printf(MSG_DEBUG, "WPS: * Encrypted Settings");
236
237 /* PKCS#5 v2.0 pad */
238 pad_len = block_size - wpabuf_len(plain) % block_size;
239 os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
240
241 wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
242 wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
243
244 iv = wpabuf_put(msg, block_size);
245 if (os_get_random(iv, block_size) < 0)
246 return -1;
247
248 data = wpabuf_put(msg, 0);
249 wpabuf_put_buf(msg, plain);
250 if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
251 return -1;
252
253 return 0;
254 }
255