Line data Source code
1 : /*
2 : * NDEF(NFC Data Exchange Format) routines for Wi-Fi Protected Setup
3 : * Reference is "NFCForum-TS-NDEF_1.0 2006-07-24".
4 : * Copyright (c) 2009-2012, Masashi Honma <masashi.honma@gmail.com>
5 : *
6 : * This software may be distributed under the terms of the BSD license.
7 : * See README for more details.
8 : */
9 :
10 : #include "includes.h"
11 : #include "common.h"
12 : #include "wps/wps.h"
13 :
14 : #define FLAG_MESSAGE_BEGIN (1 << 7)
15 : #define FLAG_MESSAGE_END (1 << 6)
16 : #define FLAG_CHUNK (1 << 5)
17 : #define FLAG_SHORT_RECORD (1 << 4)
18 : #define FLAG_ID_LENGTH_PRESENT (1 << 3)
19 : #define FLAG_TNF_NFC_FORUM (0x01)
20 : #define FLAG_TNF_RFC2046 (0x02)
21 :
22 : struct ndef_record {
23 : const u8 *type;
24 : const u8 *id;
25 : const u8 *payload;
26 : u8 type_length;
27 : u8 id_length;
28 : u32 payload_length;
29 : u32 total_length;
30 : };
31 :
32 : static const char wifi_handover_type[] = "application/vnd.wfa.wsc";
33 : static const char p2p_handover_type[] = "application/vnd.wfa.p2p";
34 :
35 117 : static int ndef_parse_record(const u8 *data, u32 size,
36 : struct ndef_record *record)
37 : {
38 117 : const u8 *pos = data + 1;
39 :
40 117 : if (size < 2)
41 2 : return -1;
42 115 : record->type_length = *pos++;
43 115 : if (data[0] & FLAG_SHORT_RECORD) {
44 88 : if (size < 3)
45 2 : return -1;
46 86 : record->payload_length = *pos++;
47 : } else {
48 : u32 len;
49 :
50 27 : if (size < 6)
51 5 : return -1;
52 22 : len = WPA_GET_BE32(pos);
53 22 : if (len > size - 6 || len > 20000)
54 18 : return -1;
55 4 : record->payload_length = len;
56 4 : pos += sizeof(u32);
57 : }
58 :
59 90 : if (data[0] & FLAG_ID_LENGTH_PRESENT) {
60 8 : if ((int) size < pos - data + 1)
61 2 : return -1;
62 6 : record->id_length = *pos++;
63 : } else
64 82 : record->id_length = 0;
65 :
66 88 : record->type = record->type_length == 0 ? NULL : pos;
67 88 : pos += record->type_length;
68 :
69 88 : record->id = record->id_length == 0 ? NULL : pos;
70 88 : pos += record->id_length;
71 :
72 88 : record->payload = record->payload_length == 0 ? NULL : pos;
73 88 : pos += record->payload_length;
74 :
75 88 : record->total_length = pos - data;
76 172 : if (record->total_length > size ||
77 84 : record->total_length < record->payload_length)
78 4 : return -1;
79 84 : return 0;
80 : }
81 :
82 :
83 113 : static struct wpabuf * ndef_parse_records(const struct wpabuf *buf,
84 : int (*filter)(struct ndef_record *))
85 : {
86 : struct ndef_record record;
87 113 : int len = wpabuf_len(buf);
88 113 : const u8 *data = wpabuf_head(buf);
89 :
90 250 : while (len > 0) {
91 117 : if (ndef_parse_record(data, len, &record) < 0) {
92 33 : wpa_printf(MSG_ERROR, "NDEF : Failed to parse");
93 33 : return NULL;
94 : }
95 84 : if (filter == NULL || filter(&record))
96 60 : return wpabuf_alloc_copy(record.payload,
97 60 : record.payload_length);
98 24 : data += record.total_length;
99 24 : len -= record.total_length;
100 : }
101 20 : wpa_printf(MSG_ERROR, "NDEF : Record not found");
102 20 : return NULL;
103 : }
104 :
105 :
106 80 : static struct wpabuf * ndef_build_record(u8 flags, const void *type,
107 : u8 type_length, void *id,
108 : u8 id_length,
109 : const struct wpabuf *payload)
110 : {
111 : struct wpabuf *record;
112 : size_t total_len;
113 : int short_record;
114 : u8 local_flag;
115 80 : size_t payload_length = wpabuf_len(payload);
116 :
117 80 : short_record = payload_length < 256 ? 1 : 0;
118 :
119 80 : total_len = 2; /* flag + type length */
120 : /* payload length */
121 80 : total_len += short_record ? sizeof(u8) : sizeof(u32);
122 80 : if (id_length > 0)
123 0 : total_len += 1;
124 80 : total_len += type_length + id_length + payload_length;
125 80 : record = wpabuf_alloc(total_len);
126 80 : if (record == NULL) {
127 5 : wpa_printf(MSG_ERROR, "NDEF : Failed to allocate "
128 : "record for build");
129 5 : return NULL;
130 : }
131 :
132 75 : local_flag = flags;
133 75 : if (id_length > 0)
134 0 : local_flag |= FLAG_ID_LENGTH_PRESENT;
135 75 : if (short_record)
136 75 : local_flag |= FLAG_SHORT_RECORD;
137 75 : wpabuf_put_u8(record, local_flag);
138 :
139 75 : wpabuf_put_u8(record, type_length);
140 :
141 75 : if (short_record)
142 75 : wpabuf_put_u8(record, payload_length);
143 : else
144 0 : wpabuf_put_be32(record, payload_length);
145 :
146 75 : if (id_length > 0)
147 0 : wpabuf_put_u8(record, id_length);
148 75 : wpabuf_put_data(record, type, type_length);
149 75 : wpabuf_put_data(record, id, id_length);
150 75 : wpabuf_put_buf(record, payload);
151 75 : return record;
152 : }
153 :
154 :
155 48 : static int wifi_filter(struct ndef_record *record)
156 : {
157 93 : if (record->type == NULL ||
158 45 : record->type_length != os_strlen(wifi_handover_type))
159 5 : return 0;
160 43 : if (os_memcmp(record->type, wifi_handover_type,
161 : os_strlen(wifi_handover_type)) != 0)
162 13 : return 0;
163 30 : return 1;
164 : }
165 :
166 :
167 63 : struct wpabuf * ndef_parse_wifi(const struct wpabuf *buf)
168 : {
169 63 : return ndef_parse_records(buf, wifi_filter);
170 : }
171 :
172 :
173 44 : struct wpabuf * ndef_build_wifi(const struct wpabuf *buf)
174 : {
175 44 : return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
176 : FLAG_TNF_RFC2046, wifi_handover_type,
177 : os_strlen(wifi_handover_type), NULL, 0, buf);
178 : }
179 :
180 :
181 36 : static int p2p_filter(struct ndef_record *record)
182 : {
183 69 : if (record->type == NULL ||
184 33 : record->type_length != os_strlen(p2p_handover_type))
185 5 : return 0;
186 31 : if (os_memcmp(record->type, p2p_handover_type,
187 : os_strlen(p2p_handover_type)) != 0)
188 1 : return 0;
189 30 : return 1;
190 : }
191 :
192 :
193 50 : struct wpabuf * ndef_parse_p2p(const struct wpabuf *buf)
194 : {
195 50 : return ndef_parse_records(buf, p2p_filter);
196 : }
197 :
198 :
199 36 : struct wpabuf * ndef_build_p2p(const struct wpabuf *buf)
200 : {
201 36 : return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
202 : FLAG_TNF_RFC2046, p2p_handover_type,
203 : os_strlen(p2p_handover_type), NULL, 0, buf);
204 : }
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