2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2014 The FreeBSD Foundation
7 * This software was developed by Edward Tomasz Napierala under sponsorship
8 * from the FreeBSD Foundation.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
39 #include <netinet/in.h>
46 chap_compute_md5(const char id, const char *secret,
47 const void *challenge, size_t challenge_len, void *response,
52 assert(response_len == CHAP_DIGEST_LEN);
55 MD5Update(&ctx, &id, sizeof(id));
56 MD5Update(&ctx, secret, strlen(secret));
57 MD5Update(&ctx, challenge, challenge_len);
58 MD5Final(response, &ctx);
62 chap_hex2int(const char hex)
109 chap_b642bin(const char *b64, void **binp, size_t *bin_lenp)
112 int b64_len, bin_len;
114 b64_len = strlen(b64);
115 bin_len = (b64_len + 3) / 4 * 3;
116 bin = calloc(bin_len, 1);
118 log_err(1, "calloc");
120 bin_len = b64_pton(b64, bin, bin_len);
122 log_warnx("malformed base64 variable");
132 * XXX: Review this _carefully_.
135 chap_hex2bin(const char *hex, void **binp, size_t *bin_lenp)
137 int i, hex_len, nibble;
138 bool lo = true; /* As opposed to 'hi'. */
140 size_t bin_off, bin_len;
142 if (strncasecmp(hex, "0b", strlen("0b")) == 0)
143 return (chap_b642bin(hex + 2, binp, bin_lenp));
145 if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
146 log_warnx("malformed variable, should start with \"0x\""
152 hex_len = strlen(hex);
154 log_warnx("malformed variable; doesn't contain anything "
159 bin_len = hex_len / 2 + hex_len % 2;
160 bin = calloc(bin_len, 1);
162 log_err(1, "calloc");
164 bin_off = bin_len - 1;
165 for (i = hex_len - 1; i >= 0; i--) {
166 nibble = chap_hex2int(hex[i]);
168 log_warnx("malformed variable, invalid char \"%c\"",
174 assert(bin_off < bin_len);
176 bin[bin_off] = nibble;
179 bin[bin_off] |= nibble << 4;
192 chap_bin2hex(const char *bin, size_t bin_len)
194 unsigned char *b64, *tmp;
197 b64_len = (bin_len + 2) / 3 * 4 + 3; /* +2 for "0b", +1 for '\0'. */
198 b64 = malloc(b64_len);
200 log_err(1, "malloc");
203 tmp += sprintf(tmp, "0b");
204 b64_ntop(bin, bin_len, tmp, b64_len - 2);
210 chap_bin2hex(const char *bin, size_t bin_len)
212 unsigned char *hex, *tmp, ch;
216 hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
217 hex = malloc(hex_len);
219 log_err(1, "malloc");
222 tmp += sprintf(tmp, "0x");
223 for (i = 0; i < bin_len; i++) {
225 tmp += sprintf(tmp, "%02x", ch);
230 #endif /* !USE_BASE64 */
237 chap = calloc(1, sizeof(*chap));
239 log_err(1, "calloc");
242 * Generate the challenge.
244 arc4random_buf(chap->chap_challenge, sizeof(chap->chap_challenge));
245 arc4random_buf(&chap->chap_id, sizeof(chap->chap_id));
251 chap_get_id(const struct chap *chap)
256 ret = asprintf(&chap_i, "%d", chap->chap_id);
258 log_err(1, "asprintf");
264 chap_get_challenge(const struct chap *chap)
268 chap_c = chap_bin2hex(chap->chap_challenge,
269 sizeof(chap->chap_challenge));
275 chap_receive_bin(struct chap *chap, void *response, size_t response_len)
278 if (response_len != sizeof(chap->chap_response)) {
279 log_debugx("got CHAP response with invalid length; "
280 "got %zd, should be %zd",
281 response_len, sizeof(chap->chap_response));
285 memcpy(chap->chap_response, response, response_len);
290 chap_receive(struct chap *chap, const char *response)
293 size_t response_bin_len;
296 error = chap_hex2bin(response, &response_bin, &response_bin_len);
298 log_debugx("got incorrectly encoded CHAP response \"%s\"",
303 error = chap_receive_bin(chap, response_bin, response_bin_len);
310 chap_authenticate(struct chap *chap, const char *secret)
312 char expected_response[CHAP_DIGEST_LEN];
314 chap_compute_md5(chap->chap_id, secret,
315 chap->chap_challenge, sizeof(chap->chap_challenge),
316 expected_response, sizeof(expected_response));
318 if (memcmp(chap->chap_response,
319 expected_response, sizeof(expected_response)) != 0) {
327 chap_delete(struct chap *chap)
334 rchap_new(const char *secret)
338 rchap = calloc(1, sizeof(*rchap));
340 log_err(1, "calloc");
342 rchap->rchap_secret = checked_strdup(secret);
348 rchap_receive_bin(struct rchap *rchap, const unsigned char id,
349 const void *challenge, size_t challenge_len)
352 rchap->rchap_id = id;
353 rchap->rchap_challenge = calloc(challenge_len, 1);
354 if (rchap->rchap_challenge == NULL)
355 log_err(1, "calloc");
356 memcpy(rchap->rchap_challenge, challenge, challenge_len);
357 rchap->rchap_challenge_len = challenge_len;
361 rchap_receive(struct rchap *rchap, const char *id, const char *challenge)
363 unsigned char id_bin;
365 size_t challenge_bin_len;
369 id_bin = strtoul(id, NULL, 10);
371 error = chap_hex2bin(challenge, &challenge_bin, &challenge_bin_len);
373 log_debugx("got incorrectly encoded CHAP challenge \"%s\"",
378 rchap_receive_bin(rchap, id_bin, challenge_bin, challenge_bin_len);
385 rchap_get_response_bin(struct rchap *rchap,
386 void **responsep, size_t *response_lenp)
389 size_t response_bin_len = CHAP_DIGEST_LEN;
391 response_bin = calloc(response_bin_len, 1);
392 if (response_bin == NULL)
393 log_err(1, "calloc");
395 chap_compute_md5(rchap->rchap_id, rchap->rchap_secret,
396 rchap->rchap_challenge, rchap->rchap_challenge_len,
397 response_bin, response_bin_len);
399 *responsep = response_bin;
400 *response_lenp = response_bin_len;
404 rchap_get_response(struct rchap *rchap)
410 rchap_get_response_bin(rchap, &response, &response_len);
411 chap_r = chap_bin2hex(response, response_len);
418 rchap_delete(struct rchap *rchap)
421 free(rchap->rchap_secret);
422 free(rchap->rchap_challenge);