xref: /freebsd/contrib/libfido2/fuzz/fuzz_cred.c (revision adf376485712c8fffbf3be330d505a969647f479)
1 /*
2  * Copyright (c) 2019 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  */
6 
7 #include <assert.h>
8 #include <stdint.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <string.h>
12 
13 #include "mutator_aux.h"
14 #include "wiredata_fido2.h"
15 #include "wiredata_u2f.h"
16 #include "dummy.h"
17 
18 #include "../openbsd-compat/openbsd-compat.h"
19 
20 /* Parameter set defining a FIDO2 make credential operation. */
21 struct param {
22 	char pin[MAXSTR];
23 	char rp_id[MAXSTR];
24 	char rp_name[MAXSTR];
25 	char user_icon[MAXSTR];
26 	char user_name[MAXSTR];
27 	char user_nick[MAXSTR];
28 	int ext;
29 	int seed;
30 	struct blob cdh;
31 	struct blob excl_cred;
32 	struct blob user_id;
33 	struct blob wire_data;
34 	uint8_t excl_count;
35 	uint8_t rk;
36 	uint8_t type;
37 	uint8_t opt;
38 	uint8_t uv;
39 };
40 
41 /*
42  * Collection of HID reports from an authenticator issued with a FIDO2
43  * make credential using the example parameters above.
44  */
45 static const uint8_t dummy_wire_data_fido[] = {
46 	WIREDATA_CTAP_INIT,
47 	WIREDATA_CTAP_CBOR_INFO,
48 	WIREDATA_CTAP_CBOR_AUTHKEY,
49 	WIREDATA_CTAP_CBOR_PINTOKEN,
50 	WIREDATA_CTAP_KEEPALIVE,
51 	WIREDATA_CTAP_KEEPALIVE,
52 	WIREDATA_CTAP_KEEPALIVE,
53 	WIREDATA_CTAP_CBOR_CRED,
54 };
55 
56 /*
57  * Collection of HID reports from an authenticator issued with a U2F
58  * registration using the example parameters above.
59  */
60 static const uint8_t dummy_wire_data_u2f[] = {
61 	WIREDATA_CTAP_INIT,
62 	WIREDATA_CTAP_U2F_6985,
63 	WIREDATA_CTAP_U2F_6985,
64 	WIREDATA_CTAP_U2F_6985,
65 	WIREDATA_CTAP_U2F_6985,
66 	WIREDATA_CTAP_U2F_6985,
67 	WIREDATA_CTAP_U2F_REGISTER,
68 };
69 
70 struct param *
71 unpack(const uint8_t *ptr, size_t len)
72 {
73 	cbor_item_t *item = NULL, **v;
74 	struct cbor_load_result cbor;
75 	struct param *p;
76 	int ok = -1;
77 
78 	if ((p = calloc(1, sizeof(*p))) == NULL ||
79 	    (item = cbor_load(ptr, len, &cbor)) == NULL ||
80 	    cbor.read != len ||
81 	    cbor_isa_array(item) == false ||
82 	    cbor_array_is_definite(item) == false ||
83 	    cbor_array_size(item) != 17 ||
84 	    (v = cbor_array_handle(item)) == NULL)
85 		goto fail;
86 
87 	if (unpack_byte(v[0], &p->rk) < 0 ||
88 	    unpack_byte(v[1], &p->type) < 0 ||
89 	    unpack_byte(v[2], &p->opt) < 0 ||
90 	    unpack_byte(v[3], &p->uv) < 0 ||
91 	    unpack_byte(v[4], &p->excl_count) < 0 ||
92 	    unpack_int(v[5], &p->ext) < 0 ||
93 	    unpack_int(v[6], &p->seed) < 0 ||
94 	    unpack_string(v[7], p->pin) < 0 ||
95 	    unpack_string(v[8], p->rp_id) < 0 ||
96 	    unpack_string(v[9], p->rp_name) < 0 ||
97 	    unpack_string(v[10], p->user_icon) < 0 ||
98 	    unpack_string(v[11], p->user_name) < 0 ||
99 	    unpack_string(v[12], p->user_nick) < 0 ||
100 	    unpack_blob(v[13], &p->cdh) < 0 ||
101 	    unpack_blob(v[14], &p->user_id) < 0 ||
102 	    unpack_blob(v[15], &p->wire_data) < 0 ||
103 	    unpack_blob(v[16], &p->excl_cred) < 0)
104 		goto fail;
105 
106 	ok = 0;
107 fail:
108 	if (ok < 0) {
109 		free(p);
110 		p = NULL;
111 	}
112 
113 	if (item)
114 		cbor_decref(&item);
115 
116 	return p;
117 }
118 
119 size_t
120 pack(uint8_t *ptr, size_t len, const struct param *p)
121 {
122 	cbor_item_t *argv[17], *array = NULL;
123 	size_t cbor_alloc_len, cbor_len = 0;
124 	unsigned char *cbor = NULL;
125 
126 	memset(argv, 0, sizeof(argv));
127 
128 	if ((array = cbor_new_definite_array(17)) == NULL ||
129 	    (argv[0] = pack_byte(p->rk)) == NULL ||
130 	    (argv[1] = pack_byte(p->type)) == NULL ||
131 	    (argv[2] = pack_byte(p->opt)) == NULL ||
132 	    (argv[3] = pack_byte(p->uv)) == NULL ||
133 	    (argv[4] = pack_byte(p->excl_count)) == NULL ||
134 	    (argv[5] = pack_int(p->ext)) == NULL ||
135 	    (argv[6] = pack_int(p->seed)) == NULL ||
136 	    (argv[7] = pack_string(p->pin)) == NULL ||
137 	    (argv[8] = pack_string(p->rp_id)) == NULL ||
138 	    (argv[9] = pack_string(p->rp_name)) == NULL ||
139 	    (argv[10] = pack_string(p->user_icon)) == NULL ||
140 	    (argv[11] = pack_string(p->user_name)) == NULL ||
141 	    (argv[12] = pack_string(p->user_nick)) == NULL ||
142 	    (argv[13] = pack_blob(&p->cdh)) == NULL ||
143 	    (argv[14] = pack_blob(&p->user_id)) == NULL ||
144 	    (argv[15] = pack_blob(&p->wire_data)) == NULL ||
145 	    (argv[16] = pack_blob(&p->excl_cred)) == NULL)
146 		goto fail;
147 
148 	for (size_t i = 0; i < 17; i++)
149 		if (cbor_array_push(array, argv[i]) == false)
150 			goto fail;
151 
152 	if ((cbor_len = cbor_serialize_alloc(array, &cbor,
153 	    &cbor_alloc_len)) > len) {
154 		cbor_len = 0;
155 		goto fail;
156 	}
157 
158 	memcpy(ptr, cbor, cbor_len);
159 fail:
160 	for (size_t i = 0; i < 17; i++)
161 		if (argv[i])
162 			cbor_decref(&argv[i]);
163 
164 	if (array)
165 		cbor_decref(&array);
166 
167 	free(cbor);
168 
169 	return cbor_len;
170 }
171 
172 size_t
173 pack_dummy(uint8_t *ptr, size_t len)
174 {
175 	struct param dummy;
176 	uint8_t blob[4096];
177 	size_t blob_len;
178 
179 	memset(&dummy, 0, sizeof(dummy));
180 
181 	dummy.type = 1;
182 	dummy.ext = FIDO_EXT_HMAC_SECRET;
183 
184 	strlcpy(dummy.pin, dummy_pin, sizeof(dummy.pin));
185 	strlcpy(dummy.rp_id, dummy_rp_id, sizeof(dummy.rp_id));
186 	strlcpy(dummy.rp_name, dummy_rp_name, sizeof(dummy.rp_name));
187 	strlcpy(dummy.user_icon, dummy_user_icon, sizeof(dummy.user_icon));
188 	strlcpy(dummy.user_name, dummy_user_name, sizeof(dummy.user_name));
189 	strlcpy(dummy.user_nick, dummy_user_nick, sizeof(dummy.user_nick));
190 
191 	dummy.cdh.len = sizeof(dummy_cdh);
192 	dummy.user_id.len = sizeof(dummy_user_id);
193 	dummy.wire_data.len = sizeof(dummy_wire_data_fido);
194 
195 	memcpy(&dummy.cdh.body, &dummy_cdh, dummy.cdh.len);
196 	memcpy(&dummy.user_id.body, &dummy_user_id, dummy.user_id.len);
197 	memcpy(&dummy.wire_data.body, &dummy_wire_data_fido,
198 	    dummy.wire_data.len);
199 
200 	assert((blob_len = pack(blob, sizeof(blob), &dummy)) != 0);
201 
202 	if (blob_len > len) {
203 		memcpy(ptr, blob, len);
204 		return len;
205 	}
206 
207 	memcpy(ptr, blob, blob_len);
208 
209 	return blob_len;
210 }
211 
212 static void
213 make_cred(fido_cred_t *cred, uint8_t opt, int type, const struct blob *cdh,
214     const char *rp_id, const char *rp_name, const struct blob *user_id,
215     const char *user_name, const char *user_nick, const char *user_icon,
216     int ext, uint8_t rk, uint8_t uv, const char *pin, uint8_t excl_count,
217     const struct blob *excl_cred)
218 {
219 	fido_dev_t *dev;
220 
221 	if ((dev = open_dev(opt & 2)) == NULL)
222 		return;
223 	if (opt & 1)
224 		fido_dev_force_u2f(dev);
225 
226 	for (uint8_t i = 0; i < excl_count; i++)
227 		fido_cred_exclude(cred, excl_cred->body, excl_cred->len);
228 
229 	fido_cred_set_type(cred, type);
230 	fido_cred_set_clientdata_hash(cred, cdh->body, cdh->len);
231 	fido_cred_set_rp(cred, rp_id, rp_name);
232 	fido_cred_set_user(cred, user_id->body, user_id->len, user_name,
233 	    user_nick, user_icon);
234 	if (ext & FIDO_EXT_HMAC_SECRET)
235 		fido_cred_set_extensions(cred, FIDO_EXT_HMAC_SECRET);
236 	if (ext & FIDO_EXT_CRED_BLOB)
237 		fido_cred_set_blob(cred, user_id->body, user_id->len);
238 	if (ext & FIDO_EXT_LARGEBLOB_KEY)
239 		fido_cred_set_extensions(cred, FIDO_EXT_LARGEBLOB_KEY);
240 
241 	if (rk & 1)
242 		fido_cred_set_rk(cred, FIDO_OPT_TRUE);
243 	if (uv & 1)
244 		fido_cred_set_uv(cred, FIDO_OPT_TRUE);
245 	if (user_id->len)
246 		fido_cred_set_prot(cred, user_id->body[0] & 0x03);
247 
248 	/* repeat memory operations to trigger reallocation paths */
249 	fido_cred_set_type(cred, type);
250 	fido_cred_set_clientdata_hash(cred, cdh->body, cdh->len);
251 	fido_cred_set_rp(cred, rp_id, rp_name);
252 	fido_cred_set_user(cred, user_id->body, user_id->len, user_name,
253 	    user_nick, user_icon);
254 
255 	if (strlen(pin) == 0)
256 		pin = NULL;
257 
258 	fido_dev_make_cred(dev, cred, (opt & 1) ? NULL : pin);
259 
260 	fido_dev_cancel(dev);
261 	fido_dev_close(dev);
262 	fido_dev_free(&dev);
263 }
264 
265 static void
266 verify_cred(int type, const unsigned char *cdh_ptr, size_t cdh_len,
267     const char *rp_id, const char *rp_name, const unsigned char *authdata_ptr,
268     size_t authdata_len, const unsigned char *authdata_raw_ptr,
269     size_t authdata_raw_len, int ext, uint8_t rk, uint8_t uv,
270     const unsigned char *x5c_ptr, size_t x5c_len, const unsigned char *sig_ptr,
271     size_t sig_len, const char *fmt, int prot)
272 {
273 	fido_cred_t *cred;
274 	uint8_t flags;
275 	uint32_t sigcount;
276 
277 	if ((cred = fido_cred_new()) == NULL)
278 		return;
279 
280 	fido_cred_set_type(cred, type);
281 	fido_cred_set_clientdata_hash(cred, cdh_ptr, cdh_len);
282 	fido_cred_set_rp(cred, rp_id, rp_name);
283 	consume(authdata_ptr, authdata_len);
284 	consume(authdata_raw_ptr, authdata_raw_len);
285 	if (fido_cred_set_authdata(cred, authdata_ptr, authdata_len) != FIDO_OK)
286 		fido_cred_set_authdata_raw(cred, authdata_raw_ptr,
287 		    authdata_raw_len);
288 	fido_cred_set_extensions(cred, ext);
289 	fido_cred_set_x509(cred, x5c_ptr, x5c_len);
290 	fido_cred_set_sig(cred, sig_ptr, sig_len);
291 	fido_cred_set_prot(cred, prot);
292 
293 	if (rk & 1)
294 		fido_cred_set_rk(cred, FIDO_OPT_TRUE);
295 	if (uv & 1)
296 		fido_cred_set_uv(cred, FIDO_OPT_TRUE);
297 	if (fmt)
298 		fido_cred_set_fmt(cred, fmt);
299 
300 	/* repeat memory operations to trigger reallocation paths */
301 	if (fido_cred_set_authdata(cred, authdata_ptr, authdata_len) != FIDO_OK)
302 		fido_cred_set_authdata_raw(cred, authdata_ptr, authdata_len);
303 	fido_cred_set_x509(cred, x5c_ptr, x5c_len);
304 	fido_cred_set_sig(cred, sig_ptr, sig_len);
305 
306 	assert(fido_cred_verify(cred) != FIDO_OK);
307 	assert(fido_cred_verify_self(cred) != FIDO_OK);
308 
309 	consume(fido_cred_pubkey_ptr(cred), fido_cred_pubkey_len(cred));
310 	consume(fido_cred_id_ptr(cred), fido_cred_id_len(cred));
311 	consume(fido_cred_aaguid_ptr(cred), fido_cred_aaguid_len(cred));
312 	consume(fido_cred_user_id_ptr(cred), fido_cred_user_id_len(cred));
313 	consume_str(fido_cred_user_name(cred));
314 	consume_str(fido_cred_display_name(cred));
315 	consume(fido_cred_largeblob_key_ptr(cred),
316 	    fido_cred_largeblob_key_len(cred));
317 
318 	flags = fido_cred_flags(cred);
319 	consume(&flags, sizeof(flags));
320 	sigcount = fido_cred_sigcount(cred);
321 	consume(&sigcount, sizeof(sigcount));
322 	type = fido_cred_type(cred);
323 	consume(&type, sizeof(type));
324 
325 	fido_cred_free(&cred);
326 }
327 
328 static void
329 test_cred(const struct param *p)
330 {
331 	fido_cred_t *cred = NULL;
332 	int cose_alg = 0;
333 
334 	if ((cred = fido_cred_new()) == NULL)
335 		return;
336 
337 	switch (p->type & 3) {
338 	case 0:
339 		cose_alg = COSE_ES256;
340 		break;
341 	case 1:
342 		cose_alg = COSE_RS256;
343 		break;
344 	default:
345 		cose_alg = COSE_EDDSA;
346 		break;
347 	}
348 
349 	set_wire_data(p->wire_data.body, p->wire_data.len);
350 
351 	make_cred(cred, p->opt, cose_alg, &p->cdh, p->rp_id, p->rp_name,
352 	    &p->user_id, p->user_name, p->user_nick, p->user_icon, p->ext,
353 	    p->rk, p->uv, p->pin, p->excl_count, &p->excl_cred);
354 
355 	verify_cred(cose_alg,
356 	    fido_cred_clientdata_hash_ptr(cred),
357 	    fido_cred_clientdata_hash_len(cred), fido_cred_rp_id(cred),
358 	    fido_cred_rp_name(cred), fido_cred_authdata_ptr(cred),
359 	    fido_cred_authdata_len(cred), fido_cred_authdata_raw_ptr(cred),
360 	    fido_cred_authdata_raw_len(cred), p->ext, p->rk, p->uv,
361 	    fido_cred_x5c_ptr(cred), fido_cred_x5c_len(cred),
362 	    fido_cred_sig_ptr(cred), fido_cred_sig_len(cred),
363 	    fido_cred_fmt(cred), fido_cred_prot(cred));
364 
365 	fido_cred_free(&cred);
366 }
367 
368 static void
369 test_touch(const struct param *p)
370 {
371 	fido_dev_t *dev;
372 	int r;
373 	int touched;
374 
375 	set_wire_data(p->wire_data.body, p->wire_data.len);
376 
377 	if ((dev = open_dev(p->opt & 2)) == NULL)
378 		return;
379 	if (p->opt & 1)
380 		fido_dev_force_u2f(dev);
381 
382 	r = fido_dev_get_touch_begin(dev);
383 	consume_str(fido_strerr(r));
384 	r = fido_dev_get_touch_status(dev, &touched, -1);
385 	consume_str(fido_strerr(r));
386 	consume(&touched, sizeof(touched));
387 
388 	fido_dev_cancel(dev);
389 	fido_dev_close(dev);
390 	fido_dev_free(&dev);
391 }
392 
393 static void
394 test_misc(const struct param *p)
395 {
396 	fido_cred_t *cred = NULL;
397 
398 	if ((cred = fido_cred_new()) == NULL)
399 		return;
400 
401 	/* reuse user id as credential id */
402 	fido_cred_set_id(cred, p->user_id.body, p->user_id.len);
403 	consume(fido_cred_id_ptr(cred), fido_cred_id_len(cred));
404 	fido_cred_free(&cred);
405 }
406 
407 void
408 test(const struct param *p)
409 {
410 	prng_init((unsigned int)p->seed);
411 	fido_init(FIDO_DEBUG);
412 	fido_set_log_handler(consume_str);
413 
414 	test_cred(p);
415 	test_touch(p);
416 	test_misc(p);
417 }
418 
419 void
420 mutate(struct param *p, unsigned int seed, unsigned int flags) NO_MSAN
421 {
422 	if (flags & MUTATE_SEED)
423 		p->seed = (int)seed;
424 
425 	if (flags & MUTATE_PARAM) {
426 		mutate_byte(&p->rk);
427 		mutate_byte(&p->type);
428 		mutate_byte(&p->opt);
429 		mutate_byte(&p->uv);
430 		mutate_byte(&p->excl_count);
431 		mutate_int(&p->ext);
432 		mutate_blob(&p->cdh);
433 		mutate_blob(&p->user_id);
434 		mutate_blob(&p->excl_cred);
435 		mutate_string(p->pin);
436 		mutate_string(p->user_icon);
437 		mutate_string(p->user_name);
438 		mutate_string(p->user_nick);
439 		mutate_string(p->rp_id);
440 		mutate_string(p->rp_name);
441 	}
442 
443 	if (flags & MUTATE_WIREDATA) {
444 		if (p->opt & 1) {
445 			p->wire_data.len = sizeof(dummy_wire_data_u2f);
446 			memcpy(&p->wire_data.body, &dummy_wire_data_u2f,
447 			    p->wire_data.len);
448 		} else {
449 			p->wire_data.len = sizeof(dummy_wire_data_fido);
450 			memcpy(&p->wire_data.body, &dummy_wire_data_fido,
451 			    p->wire_data.len);
452 		}
453 		mutate_blob(&p->wire_data);
454 	}
455 }
456