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 char wifi_handover_type[] = "application/vnd.wfa.wsc";
33 : static char p2p_handover_type[] = "application/vnd.wfa.p2p";
34 :
35 93 : static int ndef_parse_record(const u8 *data, u32 size,
36 : struct ndef_record *record)
37 : {
38 93 : const u8 *pos = data + 1;
39 :
40 93 : if (size < 2)
41 2 : return -1;
42 91 : record->type_length = *pos++;
43 91 : if (data[0] & FLAG_SHORT_RECORD) {
44 80 : if (size < 3)
45 2 : return -1;
46 78 : record->payload_length = *pos++;
47 : } else {
48 11 : if (size < 6)
49 5 : return -1;
50 6 : record->payload_length = ntohl(*(u32 *)pos);
51 6 : pos += sizeof(u32);
52 : }
53 :
54 84 : if (data[0] & FLAG_ID_LENGTH_PRESENT) {
55 10 : if ((int) size < pos - data + 1)
56 2 : return -1;
57 8 : record->id_length = *pos++;
58 : } else
59 74 : record->id_length = 0;
60 :
61 82 : record->type = record->type_length == 0 ? NULL : pos;
62 82 : pos += record->type_length;
63 :
64 82 : record->id = record->id_length == 0 ? NULL : pos;
65 82 : pos += record->id_length;
66 :
67 82 : record->payload = record->payload_length == 0 ? NULL : pos;
68 82 : pos += record->payload_length;
69 :
70 82 : record->total_length = pos - data;
71 82 : if (record->total_length > size)
72 8 : return -1;
73 74 : return 0;
74 : }
75 :
76 :
77 89 : static struct wpabuf * ndef_parse_records(const struct wpabuf *buf,
78 : int (*filter)(struct ndef_record *))
79 : {
80 : struct ndef_record record;
81 89 : int len = wpabuf_len(buf);
82 89 : const u8 *data = wpabuf_head(buf);
83 :
84 197 : while (len > 0) {
85 93 : if (ndef_parse_record(data, len, &record) < 0) {
86 19 : wpa_printf(MSG_ERROR, "NDEF : Failed to parse");
87 19 : return NULL;
88 : }
89 74 : if (filter == NULL || filter(&record))
90 55 : return wpabuf_alloc_copy(record.payload,
91 55 : record.payload_length);
92 19 : data += record.total_length;
93 19 : len -= record.total_length;
94 : }
95 15 : wpa_printf(MSG_ERROR, "NDEF : Record not found");
96 15 : return NULL;
97 : }
98 :
99 :
100 69 : static struct wpabuf * ndef_build_record(u8 flags, void *type,
101 : u8 type_length, void *id,
102 : u8 id_length,
103 : const struct wpabuf *payload)
104 : {
105 : struct wpabuf *record;
106 : size_t total_len;
107 : int short_record;
108 : u8 local_flag;
109 69 : size_t payload_length = wpabuf_len(payload);
110 :
111 69 : short_record = payload_length < 256 ? 1 : 0;
112 :
113 69 : total_len = 2; /* flag + type length */
114 : /* payload length */
115 69 : total_len += short_record ? sizeof(u8) : sizeof(u32);
116 69 : if (id_length > 0)
117 0 : total_len += 1;
118 69 : total_len += type_length + id_length + payload_length;
119 69 : record = wpabuf_alloc(total_len);
120 69 : if (record == NULL) {
121 0 : wpa_printf(MSG_ERROR, "NDEF : Failed to allocate "
122 : "record for build");
123 0 : return NULL;
124 : }
125 :
126 69 : local_flag = flags;
127 69 : if (id_length > 0)
128 0 : local_flag |= FLAG_ID_LENGTH_PRESENT;
129 69 : if (short_record)
130 69 : local_flag |= FLAG_SHORT_RECORD;
131 69 : wpabuf_put_u8(record, local_flag);
132 :
133 69 : wpabuf_put_u8(record, type_length);
134 :
135 69 : if (short_record)
136 69 : wpabuf_put_u8(record, payload_length);
137 : else
138 0 : wpabuf_put_be32(record, payload_length);
139 :
140 69 : if (id_length > 0)
141 0 : wpabuf_put_u8(record, id_length);
142 69 : wpabuf_put_data(record, type, type_length);
143 69 : wpabuf_put_data(record, id, id_length);
144 69 : wpabuf_put_buf(record, payload);
145 69 : return record;
146 : }
147 :
148 :
149 44 : static int wifi_filter(struct ndef_record *record)
150 : {
151 85 : if (record->type == NULL ||
152 41 : record->type_length != os_strlen(wifi_handover_type))
153 5 : return 0;
154 39 : if (os_memcmp(record->type, wifi_handover_type,
155 : os_strlen(wifi_handover_type)) != 0)
156 9 : return 0;
157 30 : return 1;
158 : }
159 :
160 :
161 52 : struct wpabuf * ndef_parse_wifi(const struct wpabuf *buf)
162 : {
163 52 : return ndef_parse_records(buf, wifi_filter);
164 : }
165 :
166 :
167 42 : struct wpabuf * ndef_build_wifi(const struct wpabuf *buf)
168 : {
169 42 : return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
170 : FLAG_TNF_RFC2046, wifi_handover_type,
171 42 : os_strlen(wifi_handover_type), NULL, 0, buf);
172 : }
173 :
174 :
175 30 : static int p2p_filter(struct ndef_record *record)
176 : {
177 57 : if (record->type == NULL ||
178 27 : record->type_length != os_strlen(p2p_handover_type))
179 5 : return 0;
180 25 : if (os_memcmp(record->type, p2p_handover_type,
181 : os_strlen(p2p_handover_type)) != 0)
182 0 : return 0;
183 25 : return 1;
184 : }
185 :
186 :
187 37 : struct wpabuf * ndef_parse_p2p(const struct wpabuf *buf)
188 : {
189 37 : return ndef_parse_records(buf, p2p_filter);
190 : }
191 :
192 :
193 27 : struct wpabuf * ndef_build_p2p(const struct wpabuf *buf)
194 : {
195 27 : return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END |
196 : FLAG_TNF_RFC2046, p2p_handover_type,
197 27 : os_strlen(p2p_handover_type), NULL, 0, buf);
198 : }
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