Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2014 The FreeBSD Foundation
 *
 * This software was developed by Edward Tomasz Napierala under sponsorship
 * from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <resolv.h>
#include <md5.h>

#include "ctld.h"

static void
chap_compute_md5(const char id, const char *secret,
    const void *challenge, size_t challenge_len, void *response,
    size_t response_len)
{
	MD5_CTX ctx;

	assert(response_len == CHAP_DIGEST_LEN);

	MD5Init(&ctx);
	MD5Update(&ctx, &id, sizeof(id));
	MD5Update(&ctx, secret, strlen(secret));
	MD5Update(&ctx, challenge, challenge_len);
	MD5Final(response, &ctx);
}

static int
chap_hex2int(const char hex)
{
	switch (hex) {
	case '0':
		return (0x00);
	case '1':
		return (0x01);
	case '2':
		return (0x02);
	case '3':
		return (0x03);
	case '4':
		return (0x04);
	case '5':
		return (0x05);
	case '6':
		return (0x06);
	case '7':
		return (0x07);
	case '8':
		return (0x08);
	case '9':
		return (0x09);
	case 'a':
	case 'A':
		return (0x0a);
	case 'b':
	case 'B':
		return (0x0b);
	case 'c':
	case 'C':
		return (0x0c);
	case 'd':
	case 'D':
		return (0x0d);
	case 'e':
	case 'E':
		return (0x0e);
	case 'f':
	case 'F':
		return (0x0f);
	default:
		return (-1);
	}
}

static int
chap_b642bin(const char *b64, void **binp, size_t *bin_lenp)
{
	char *bin;
	int b64_len, bin_len;

	b64_len = strlen(b64);
	bin_len = (b64_len + 3) / 4 * 3;
	bin = calloc(bin_len, 1);
	if (bin == NULL)
		log_err(1, "calloc");

	bin_len = b64_pton(b64, bin, bin_len);
	if (bin_len < 0) {
		log_warnx("malformed base64 variable");
		free(bin);
		return (-1);
	}
	*binp = bin;
	*bin_lenp = bin_len;
	return (0);
}

/*
 * XXX: Review this _carefully_.
 */
static int
chap_hex2bin(const char *hex, void **binp, size_t *bin_lenp)
{
	int i, hex_len, nibble;
	bool lo = true; /* As opposed to 'hi'. */
	char *bin;
	size_t bin_off, bin_len;

	if (strncasecmp(hex, "0b", strlen("0b")) == 0)
		return (chap_b642bin(hex + 2, binp, bin_lenp));

	if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
		log_warnx("malformed variable, should start with \"0x\""
		    " or \"0b\"");
		return (-1);
	}

	hex += strlen("0x");
	hex_len = strlen(hex);
	if (hex_len < 1) {
		log_warnx("malformed variable; doesn't contain anything "
		    "but \"0x\"");
		return (-1);
	}

	bin_len = hex_len / 2 + hex_len % 2;
	bin = calloc(bin_len, 1);
	if (bin == NULL)
		log_err(1, "calloc");

	bin_off = bin_len - 1;
	for (i = hex_len - 1; i >= 0; i--) {
		nibble = chap_hex2int(hex[i]);
		if (nibble < 0) {
			log_warnx("malformed variable, invalid char \"%c\"",
			    hex[i]);
			free(bin);
			return (-1);
		}

		assert(bin_off < bin_len);
		if (lo) {
			bin[bin_off] = nibble;
			lo = false;
		} else {
			bin[bin_off] |= nibble << 4;
			bin_off--;
			lo = true;
		}
	}

	*binp = bin;
	*bin_lenp = bin_len;
	return (0);
}

#ifdef USE_BASE64
static char *
chap_bin2hex(const char *bin, size_t bin_len)
{
	unsigned char *b64, *tmp;
	size_t b64_len;

	b64_len = (bin_len + 2) / 3 * 4 + 3; /* +2 for "0b", +1 for '\0'. */
	b64 = malloc(b64_len);
	if (b64 == NULL)
		log_err(1, "malloc");

	tmp = b64;
	tmp += sprintf(tmp, "0b");
	b64_ntop(bin, bin_len, tmp, b64_len - 2);

	return (b64);
}
#else
static char *
chap_bin2hex(const char *bin, size_t bin_len)
{
	unsigned char *hex, *tmp, ch;
	size_t hex_len;
	size_t i;

	hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
	hex = malloc(hex_len);
	if (hex == NULL)
		log_err(1, "malloc");

	tmp = hex;
	tmp += sprintf(tmp, "0x");
	for (i = 0; i < bin_len; i++) {
		ch = bin[i];
		tmp += sprintf(tmp, "%02x", ch);
	}

	return (hex);
}
#endif /* !USE_BASE64 */

struct chap *
chap_new(void)
{
	struct chap *chap;

	chap = calloc(1, sizeof(*chap));
	if (chap == NULL)
		log_err(1, "calloc");

	/*
	 * Generate the challenge.
	 */
	arc4random_buf(chap->chap_challenge, sizeof(chap->chap_challenge));
	arc4random_buf(&chap->chap_id, sizeof(chap->chap_id));

	return (chap);
}

char *
chap_get_id(const struct chap *chap)
{
	char *chap_i;
	int ret;

	ret = asprintf(&chap_i, "%d", chap->chap_id);
	if (ret < 0)
		log_err(1, "asprintf");

	return (chap_i);
}

char *
chap_get_challenge(const struct chap *chap)
{
	char *chap_c;

	chap_c = chap_bin2hex(chap->chap_challenge,
	    sizeof(chap->chap_challenge));

	return (chap_c);
}

static int
chap_receive_bin(struct chap *chap, void *response, size_t response_len)
{

	if (response_len != sizeof(chap->chap_response)) {
		log_debugx("got CHAP response with invalid length; "
		    "got %zd, should be %zd",
		    response_len, sizeof(chap->chap_response));
		return (1);
	}

	memcpy(chap->chap_response, response, response_len);
	return (0);
}

int
chap_receive(struct chap *chap, const char *response)
{
	void *response_bin;
	size_t response_bin_len;
	int error;

	error = chap_hex2bin(response, &response_bin, &response_bin_len);
	if (error != 0) {
		log_debugx("got incorrectly encoded CHAP response \"%s\"",
		    response);
		return (1);
	}

	error = chap_receive_bin(chap, response_bin, response_bin_len);
	free(response_bin);

	return (error);
}

int
chap_authenticate(struct chap *chap, const char *secret)
{
	char expected_response[CHAP_DIGEST_LEN];

	chap_compute_md5(chap->chap_id, secret,
	    chap->chap_challenge, sizeof(chap->chap_challenge),
	    expected_response, sizeof(expected_response));

	if (memcmp(chap->chap_response,
	    expected_response, sizeof(expected_response)) != 0) {
		return (-1);
	}

	return (0);
}

void
chap_delete(struct chap *chap)
{

	free(chap);
}

struct rchap *
rchap_new(const char *secret)
{
	struct rchap *rchap;

	rchap = calloc(1, sizeof(*rchap));
	if (rchap == NULL)
		log_err(1, "calloc");

	rchap->rchap_secret = checked_strdup(secret);

	return (rchap);
}

static void
rchap_receive_bin(struct rchap *rchap, const unsigned char id,
    const void *challenge, size_t challenge_len)
{

	rchap->rchap_id = id;
	rchap->rchap_challenge = calloc(challenge_len, 1);
	if (rchap->rchap_challenge == NULL)
		log_err(1, "calloc");
	memcpy(rchap->rchap_challenge, challenge, challenge_len);
	rchap->rchap_challenge_len = challenge_len;
}

int
rchap_receive(struct rchap *rchap, const char *id, const char *challenge)
{
	unsigned char id_bin;
	void *challenge_bin;
	size_t challenge_bin_len;

	int error;

	id_bin = strtoul(id, NULL, 10);

	error = chap_hex2bin(challenge, &challenge_bin, &challenge_bin_len);
	if (error != 0) {
		log_debugx("got incorrectly encoded CHAP challenge \"%s\"",
		    challenge);
		return (1);
	}

	rchap_receive_bin(rchap, id_bin, challenge_bin, challenge_bin_len);
	free(challenge_bin);

	return (0);
}

static void
rchap_get_response_bin(struct rchap *rchap,
    void **responsep, size_t *response_lenp)
{
	void *response_bin;
	size_t response_bin_len = CHAP_DIGEST_LEN;

	response_bin = calloc(response_bin_len, 1);
	if (response_bin == NULL)
		log_err(1, "calloc");

	chap_compute_md5(rchap->rchap_id, rchap->rchap_secret,
	    rchap->rchap_challenge, rchap->rchap_challenge_len,
	    response_bin, response_bin_len);

	*responsep = response_bin;
	*response_lenp = response_bin_len;
}

char *
rchap_get_response(struct rchap *rchap)
{
	void *response;
	size_t response_len;
	char *chap_r;

	rchap_get_response_bin(rchap, &response, &response_len);
	chap_r = chap_bin2hex(response, response_len);
	free(response);

	return (chap_r);
}

void
rchap_delete(struct rchap *rchap)
{

	free(rchap->rchap_secret);
	free(rchap->rchap_challenge);
	free(rchap);
}