Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * Copyright (c) 2020-2022 Yubico AB. All rights reserved. |
3 | | * Use of this source code is governed by a BSD-style |
4 | | * license that can be found in the LICENSE file. |
5 | | * SPDX-License-Identifier: BSD-2-Clause |
6 | | */ |
7 | | |
8 | | #include <stdio.h> |
9 | | #include <string.h> |
10 | | |
11 | | #include "fido.h" |
12 | | #include "fido/param.h" |
13 | | #include "iso7816.h" |
14 | | |
15 | 4.28k | #define TX_CHUNK_SIZE 240 |
16 | | |
17 | | static const uint8_t aid[] = { 0xa0, 0x00, 0x00, 0x06, 0x47, 0x2f, 0x00, 0x01 }; |
18 | | static const uint8_t v_u2f[] = { 'U', '2', 'F', '_', 'V', '2' }; |
19 | | static const uint8_t v_fido[] = { 'F', 'I', 'D', 'O', '_', '2', '_', '0' }; |
20 | | |
21 | | static int |
22 | | tx_short_apdu(fido_dev_t *d, const iso7816_header_t *h, const uint8_t *payload, |
23 | | uint8_t payload_len, uint8_t cla_flags) |
24 | 4.11k | { |
25 | 4.11k | uint8_t apdu[5 + UINT8_MAX + 1]; |
26 | 4.11k | uint8_t sw[2]; |
27 | 4.11k | size_t apdu_len; |
28 | 4.11k | int ok = -1; |
29 | | |
30 | 4.11k | memset(&apdu, 0, sizeof(apdu)); |
31 | 4.11k | apdu[0] = h->cla | cla_flags; |
32 | 4.11k | apdu[1] = h->ins; |
33 | 4.11k | apdu[2] = h->p1; |
34 | 4.11k | apdu[3] = h->p2; |
35 | 4.11k | apdu[4] = payload_len; |
36 | 4.11k | memcpy(&apdu[5], payload, payload_len); |
37 | 4.11k | apdu_len = (size_t)(5 + payload_len + 1); |
38 | | |
39 | 4.11k | if (d->io.write(d->io_handle, apdu, apdu_len) < 0) { |
40 | 60 | fido_log_debug("%s: write", __func__); |
41 | 60 | goto fail; |
42 | 60 | } |
43 | | |
44 | 4.05k | if (cla_flags & 0x10) { |
45 | 156 | if (d->io.read(d->io_handle, sw, sizeof(sw), -1) != 2) { |
46 | 72 | fido_log_debug("%s: read", __func__); |
47 | 72 | goto fail; |
48 | 72 | } |
49 | 84 | if ((sw[0] << 8 | sw[1]) != SW_NO_ERROR) { |
50 | 76 | fido_log_debug("%s: unexpected sw", __func__); |
51 | 76 | goto fail; |
52 | 76 | } |
53 | 84 | } |
54 | | |
55 | 3.90k | ok = 0; |
56 | 4.11k | fail: |
57 | 4.11k | explicit_bzero(apdu, sizeof(apdu)); |
58 | | |
59 | 4.11k | return ok; |
60 | 3.90k | } |
61 | | |
62 | | static int |
63 | | nfc_do_tx(fido_dev_t *d, const uint8_t *apdu_ptr, size_t apdu_len) |
64 | 4.18k | { |
65 | 4.18k | iso7816_header_t h; |
66 | | |
67 | 4.18k | if (fido_buf_read(&apdu_ptr, &apdu_len, &h, sizeof(h)) < 0) { |
68 | 79 | fido_log_debug("%s: header", __func__); |
69 | 79 | return -1; |
70 | 79 | } |
71 | 4.10k | if (apdu_len < 2) { |
72 | 2 | fido_log_debug("%s: apdu_len %zu", __func__, apdu_len); |
73 | 2 | return -1; |
74 | 2 | } |
75 | | |
76 | 4.10k | apdu_len -= 2; /* trim le1 le2 */ |
77 | | |
78 | 4.11k | while (apdu_len > TX_CHUNK_SIZE) { |
79 | 156 | if (tx_short_apdu(d, &h, apdu_ptr, TX_CHUNK_SIZE, 0x10) < 0) { |
80 | 148 | fido_log_debug("%s: chain", __func__); |
81 | 148 | return -1; |
82 | 148 | } |
83 | 8 | apdu_ptr += TX_CHUNK_SIZE; |
84 | 8 | apdu_len -= TX_CHUNK_SIZE; |
85 | 8 | } |
86 | | |
87 | 3.95k | if (tx_short_apdu(d, &h, apdu_ptr, (uint8_t)apdu_len, 0) < 0) { |
88 | 60 | fido_log_debug("%s: tx_short_apdu", __func__); |
89 | 60 | return -1; |
90 | 60 | } |
91 | | |
92 | 3.89k | return 0; |
93 | 3.95k | } |
94 | | |
95 | | int |
96 | | fido_nfc_tx(fido_dev_t *d, uint8_t cmd, const unsigned char *buf, size_t count) |
97 | 4.58k | { |
98 | 4.58k | iso7816_apdu_t *apdu = NULL; |
99 | 4.58k | const uint8_t *ptr; |
100 | 4.58k | size_t len; |
101 | 4.58k | int ok = -1; |
102 | | |
103 | 4.58k | switch (cmd) { |
104 | 2.40k | case CTAP_CMD_INIT: /* select */ |
105 | 2.40k | if ((apdu = iso7816_new(0, 0xa4, 0x04, sizeof(aid))) == NULL || |
106 | 2.40k | iso7816_add(apdu, aid, sizeof(aid)) < 0) { |
107 | 19 | fido_log_debug("%s: iso7816", __func__); |
108 | 19 | goto fail; |
109 | 19 | } |
110 | 2.38k | break; |
111 | 2.38k | case CTAP_CMD_CBOR: /* wrap cbor */ |
112 | 1.21k | if (count > UINT16_MAX || (apdu = iso7816_new(0x80, 0x10, 0x00, |
113 | 1.20k | (uint16_t)count)) == NULL || |
114 | 1.21k | iso7816_add(apdu, buf, count) < 0) { |
115 | 19 | fido_log_debug("%s: iso7816", __func__); |
116 | 19 | goto fail; |
117 | 19 | } |
118 | 1.19k | break; |
119 | 1.19k | case CTAP_CMD_MSG: /* already an apdu */ |
120 | 609 | break; |
121 | 364 | default: |
122 | 364 | fido_log_debug("%s: cmd=%02x", __func__, cmd); |
123 | 364 | goto fail; |
124 | 4.58k | } |
125 | | |
126 | 4.18k | if (apdu != NULL) { |
127 | 3.57k | ptr = iso7816_ptr(apdu); |
128 | 3.57k | len = iso7816_len(apdu); |
129 | 3.57k | } else { |
130 | 609 | ptr = buf; |
131 | 609 | len = count; |
132 | 609 | } |
133 | | |
134 | 4.18k | if (nfc_do_tx(d, ptr, len) < 0) { |
135 | 289 | fido_log_debug("%s: nfc_do_tx", __func__); |
136 | 289 | goto fail; |
137 | 289 | } |
138 | | |
139 | 3.89k | ok = 0; |
140 | 4.58k | fail: |
141 | 4.58k | iso7816_free(&apdu); |
142 | | |
143 | 4.58k | return ok; |
144 | 3.89k | } |
145 | | |
146 | | static int |
147 | | rx_init(fido_dev_t *d, unsigned char *buf, size_t count, int ms) |
148 | 2.29k | { |
149 | 2.29k | fido_ctap_info_t *attr = (fido_ctap_info_t *)buf; |
150 | 2.29k | uint8_t f[64]; |
151 | 2.29k | int n; |
152 | | |
153 | 2.29k | if (count != sizeof(*attr)) { |
154 | 157 | fido_log_debug("%s: count=%zu", __func__, count); |
155 | 157 | return -1; |
156 | 157 | } |
157 | | |
158 | 2.14k | memset(attr, 0, sizeof(*attr)); |
159 | | |
160 | 2.14k | if ((n = d->io.read(d->io_handle, f, sizeof(f), ms)) < 2 || |
161 | 2.14k | (f[n - 2] << 8 | f[n - 1]) != SW_NO_ERROR) { |
162 | 1.19k | fido_log_debug("%s: read", __func__); |
163 | 1.19k | return -1; |
164 | 1.19k | } |
165 | | |
166 | 943 | n -= 2; |
167 | | |
168 | 943 | if (n == sizeof(v_u2f) && memcmp(f, v_u2f, sizeof(v_u2f)) == 0) |
169 | 7 | attr->flags = FIDO_CAP_CBOR; |
170 | 936 | else if (n == sizeof(v_fido) && memcmp(f, v_fido, sizeof(v_fido)) == 0) |
171 | 7 | attr->flags = FIDO_CAP_CBOR | FIDO_CAP_NMSG; |
172 | 929 | else { |
173 | 929 | fido_log_debug("%s: unknown version string", __func__); |
174 | 929 | #ifdef FIDO_FUZZ |
175 | 929 | attr->flags = FIDO_CAP_CBOR | FIDO_CAP_NMSG; |
176 | | #else |
177 | | return -1; |
178 | | #endif |
179 | 929 | } |
180 | | |
181 | 943 | memcpy(&attr->nonce, &d->nonce, sizeof(attr->nonce)); /* XXX */ |
182 | | |
183 | 943 | return (int)count; |
184 | 2.14k | } |
185 | | |
186 | | static int |
187 | | tx_get_response(fido_dev_t *d, uint8_t count) |
188 | 154 | { |
189 | 154 | uint8_t apdu[5]; |
190 | | |
191 | 154 | memset(apdu, 0, sizeof(apdu)); |
192 | 154 | apdu[1] = 0xc0; /* GET_RESPONSE */ |
193 | 154 | apdu[4] = count; |
194 | | |
195 | 154 | if (d->io.write(d->io_handle, apdu, sizeof(apdu)) < 0) { |
196 | 9 | fido_log_debug("%s: write", __func__); |
197 | 9 | return -1; |
198 | 9 | } |
199 | | |
200 | 145 | return 0; |
201 | 154 | } |
202 | | |
203 | | static int |
204 | | rx_apdu(fido_dev_t *d, uint8_t sw[2], unsigned char **buf, size_t *count, int *ms) |
205 | 1.84k | { |
206 | 1.84k | uint8_t f[256 + 2]; |
207 | 1.84k | struct timespec ts; |
208 | 1.84k | int n, ok = -1; |
209 | | |
210 | 1.84k | if (fido_time_now(&ts) != 0) |
211 | 24 | goto fail; |
212 | | |
213 | 1.82k | if ((n = d->io.read(d->io_handle, f, sizeof(f), *ms)) < 2) { |
214 | 1.15k | fido_log_debug("%s: read", __func__); |
215 | 1.15k | goto fail; |
216 | 1.15k | } |
217 | | |
218 | 666 | if (fido_time_delta(&ts, ms) != 0) |
219 | 19 | goto fail; |
220 | | |
221 | 647 | if (fido_buf_write(buf, count, f, (size_t)(n - 2)) < 0) { |
222 | 0 | fido_log_debug("%s: fido_buf_write", __func__); |
223 | 0 | goto fail; |
224 | 0 | } |
225 | | |
226 | 647 | memcpy(sw, f + n - 2, 2); |
227 | | |
228 | 647 | ok = 0; |
229 | 1.84k | fail: |
230 | 1.84k | explicit_bzero(f, sizeof(f)); |
231 | | |
232 | 1.84k | return ok; |
233 | 647 | } |
234 | | |
235 | | static int |
236 | | rx_msg(fido_dev_t *d, unsigned char *buf, size_t count, int ms) |
237 | 1.70k | { |
238 | 1.70k | uint8_t sw[2]; |
239 | 1.70k | const size_t bufsiz = count; |
240 | | |
241 | 1.70k | if (rx_apdu(d, sw, &buf, &count, &ms) < 0) { |
242 | 1.11k | fido_log_debug("%s: preamble", __func__); |
243 | 1.11k | return -1; |
244 | 1.11k | } |
245 | | |
246 | 647 | while (sw[0] == SW1_MORE_DATA) |
247 | 154 | if (tx_get_response(d, sw[1]) < 0 || |
248 | 154 | rx_apdu(d, sw, &buf, &count, &ms) < 0) { |
249 | 89 | fido_log_debug("%s: chain", __func__); |
250 | 89 | return -1; |
251 | 89 | } |
252 | | |
253 | 493 | if (fido_buf_write(&buf, &count, sw, sizeof(sw)) < 0) { |
254 | 0 | fido_log_debug("%s: sw", __func__); |
255 | 0 | return -1; |
256 | 0 | } |
257 | | |
258 | 493 | if (bufsiz - count > INT_MAX) { |
259 | 0 | fido_log_debug("%s: bufsiz", __func__); |
260 | 0 | return -1; |
261 | 0 | } |
262 | | |
263 | 493 | return (int)(bufsiz - count); |
264 | 493 | } |
265 | | |
266 | | static int |
267 | | rx_cbor(fido_dev_t *d, unsigned char *buf, size_t count, int ms) |
268 | 1.12k | { |
269 | 1.12k | int r; |
270 | | |
271 | 1.12k | if ((r = rx_msg(d, buf, count, ms)) < 2) |
272 | 728 | return -1; |
273 | | |
274 | 398 | return r - 2; |
275 | 1.12k | } |
276 | | |
277 | | int |
278 | | fido_nfc_rx(fido_dev_t *d, uint8_t cmd, unsigned char *buf, size_t count, int ms) |
279 | 4.18k | { |
280 | 4.18k | switch (cmd) { |
281 | 2.29k | case CTAP_CMD_INIT: |
282 | 2.29k | return rx_init(d, buf, count, ms); |
283 | 1.12k | case CTAP_CMD_CBOR: |
284 | 1.12k | return rx_cbor(d, buf, count, ms); |
285 | 575 | case CTAP_CMD_MSG: |
286 | 575 | return rx_msg(d, buf, count, ms); |
287 | 189 | default: |
288 | 189 | fido_log_debug("%s: cmd=%02x", __func__, cmd); |
289 | 189 | return -1; |
290 | 4.18k | } |
291 | 4.18k | } |
292 | | |
293 | | bool |
294 | | nfc_is_fido(const char *path) |
295 | 554k | { |
296 | 554k | bool fido = false; |
297 | 554k | fido_dev_t *d; |
298 | 554k | int r; |
299 | | |
300 | 554k | if ((d = fido_dev_new()) == NULL) { |
301 | 1.33k | fido_log_debug("%s: fido_dev_new", __func__); |
302 | 1.33k | goto fail; |
303 | 1.33k | } |
304 | | /* fido_dev_open selects the fido applet */ |
305 | 552k | if ((r = fido_dev_open(d, path)) != FIDO_OK) { |
306 | 552k | fido_log_debug("%s: fido_dev_open: 0x%x", __func__, r); |
307 | 552k | goto fail; |
308 | 552k | } |
309 | 94 | if ((r = fido_dev_close(d)) != FIDO_OK) { |
310 | 0 | fido_log_debug("%s: fido_dev_close: 0x%x", __func__, r); |
311 | 0 | goto fail; |
312 | |
|
313 | 0 | } |
314 | | |
315 | 94 | fido = true; |
316 | 554k | fail: |
317 | 554k | fido_dev_free(&d); |
318 | | |
319 | 554k | return fido; |
320 | 94 | } |
321 | | |
322 | | #ifdef USE_NFC |
323 | | bool |
324 | | fido_is_nfc(const char *path) |
325 | 619k | { |
326 | 619k | return strncmp(path, FIDO_NFC_PREFIX, strlen(FIDO_NFC_PREFIX)) == 0; |
327 | 619k | } |
328 | | |
329 | | int |
330 | | fido_dev_set_nfc(fido_dev_t *d) |
331 | 551k | { |
332 | 551k | if (d->io_handle != NULL) { |
333 | 0 | fido_log_debug("%s: device open", __func__); |
334 | 0 | return -1; |
335 | 0 | } |
336 | 551k | d->io_own = true; |
337 | 551k | d->io = (fido_dev_io_t) { |
338 | 551k | fido_nfc_open, |
339 | 551k | fido_nfc_close, |
340 | 551k | fido_nfc_read, |
341 | 551k | fido_nfc_write, |
342 | 551k | }; |
343 | 551k | d->transport = (fido_dev_transport_t) { |
344 | 551k | fido_nfc_rx, |
345 | 551k | fido_nfc_tx, |
346 | 551k | }; |
347 | | |
348 | 551k | return 0; |
349 | 551k | } |
350 | | #endif /* USE_NFC */ |