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1/* $OpenBSD: jpake.c,v 1.1 2008/11/04 08:22:12 djm Exp $ */
2/*
3 * Copyright (c) 2008 Damien Miller. All rights reserved.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/*
19 * Shared components of zero-knowledge password auth using J-PAKE protocol
20 * as described in:
21 *
22 * F. Hao, P. Ryan, "Password Authenticated Key Exchange by Juggling",
23 * 16th Workshop on Security Protocols, Cambridge, April 2008
24 *
25 * http://grouper.ieee.org/groups/1363/Research/contributions/hao-ryan-2008.pdf
26 */
27
28#include "includes.h"
29
30#include <sys/types.h>
31
32#include <stdio.h>
33#include <string.h>
34#include <stdarg.h>
35
36#include <openssl/bn.h>
37#include <openssl/evp.h>
38
39#include "xmalloc.h"
40#include "ssh2.h"
41#include "key.h"
42#include "hostfile.h"
43#include "auth.h"
44#include "buffer.h"
45#include "packet.h"
46#include "dispatch.h"
47#include "log.h"
48
49#include "jpake.h"
50
51#ifdef JPAKE
52
53/* RFC3526 group 5, 1536 bits */
54#define JPAKE_GROUP_G "2"
55#define JPAKE_GROUP_P \
56 "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74" \
57 "020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F1437" \
58 "4FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \
59 "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF05" \
60 "98DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB" \
61 "9ED529077096966D670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF"
62
63struct jpake_group *
64jpake_default_group(void)
65{
66 struct jpake_group *ret;
67
68 ret = xmalloc(sizeof(*ret));
69 ret->p = ret->q = ret->g = NULL;
70 if (BN_hex2bn(&ret->p, JPAKE_GROUP_P) == 0 ||
71 BN_hex2bn(&ret->g, JPAKE_GROUP_G) == 0)
72 fatal("%s: BN_hex2bn", __func__);
73 /* Subgroup order is p/2 (p is a safe prime) */
74 if ((ret->q = BN_new()) == NULL)
75 fatal("%s: BN_new", __func__);
76 if (BN_rshift1(ret->q, ret->p) != 1)
77 fatal("%s: BN_rshift1", __func__);
78
79 return ret;
80}
81
82/*
83 * Generate uniformly distributed random number in range (1, high).
84 * Return number on success, NULL on failure.
85 */
86BIGNUM *
87bn_rand_range_gt_one(const BIGNUM *high)
88{
89 BIGNUM *r, *tmp;
90 int success = -1;
91
92 if ((tmp = BN_new()) == NULL) {
93 error("%s: BN_new", __func__);
94 return NULL;
95 }
96 if ((r = BN_new()) == NULL) {
97 error("%s: BN_new failed", __func__);
98 goto out;
99 }
100 if (BN_set_word(tmp, 2) != 1) {
101 error("%s: BN_set_word(tmp, 2)", __func__);
102 goto out;
103 }
104 if (BN_sub(tmp, high, tmp) == -1) {
105 error("%s: BN_sub failed (tmp = high - 2)", __func__);
106 goto out;
107 }
108 if (BN_rand_range(r, tmp) == -1) {
109 error("%s: BN_rand_range failed", __func__);
110 goto out;
111 }
112 if (BN_set_word(tmp, 2) != 1) {
113 error("%s: BN_set_word(tmp, 2)", __func__);
114 goto out;
115 }
116 if (BN_add(r, r, tmp) == -1) {
117 error("%s: BN_add failed (r = r + 2)", __func__);
118 goto out;
119 }
120 success = 0;
121 out:
122 BN_clear_free(tmp);
123 if (success == 0)
124 return r;
125 BN_clear_free(r);
126 return NULL;
127}
128
129/*
130 * Hash contents of buffer 'b' with hash 'md'. Returns 0 on success,
131 * with digest via 'digestp' (caller to free) and length via 'lenp'.
132 * Returns -1 on failure.
133 */
134int
135hash_buffer(const u_char *buf, u_int len, const EVP_MD *md,
136 u_char **digestp, u_int *lenp)
137{
138 u_char digest[EVP_MAX_MD_SIZE];
139 u_int digest_len;
140 EVP_MD_CTX evp_md_ctx;
141 int success = -1;
142
143 EVP_MD_CTX_init(&evp_md_ctx);
144
145 if (EVP_DigestInit_ex(&evp_md_ctx, md, NULL) != 1) {
146 error("%s: EVP_DigestInit_ex", __func__);
147 goto out;
148 }
149 if (EVP_DigestUpdate(&evp_md_ctx, buf, len) != 1) {
150 error("%s: EVP_DigestUpdate", __func__);
151 goto out;
152 }
153 if (EVP_DigestFinal_ex(&evp_md_ctx, digest, &digest_len) != 1) {
154 error("%s: EVP_DigestFinal_ex", __func__);
155 goto out;
156 }
157 *digestp = xmalloc(digest_len);
158 *lenp = digest_len;
159 memcpy(*digestp, digest, *lenp);
160 success = 0;
161 out:
162 EVP_MD_CTX_cleanup(&evp_md_ctx);
163 bzero(digest, sizeof(digest));
164 digest_len = 0;
165 return success;
166}
167
168/* print formatted string followed by bignum */
169void
170jpake_debug3_bn(const BIGNUM *n, const char *fmt, ...)
171{
172 char *out, *h;
173 va_list args;
174
175 out = NULL;
176 va_start(args, fmt);
177 vasprintf(&out, fmt, args);
178 va_end(args);
179 if (out == NULL)
180 fatal("%s: vasprintf failed", __func__);
181
182 if (n == NULL)
183 debug3("%s(null)", out);
184 else {
185 h = BN_bn2hex(n);
186 debug3("%s0x%s", out, h);
187 free(h);
188 }
189 free(out);
190}
191
192/* print formatted string followed by buffer contents in hex */
193void
194jpake_debug3_buf(const u_char *buf, u_int len, const char *fmt, ...)
195{
196 char *out, h[65];
197 u_int i, j;
198 va_list args;
199
200 out = NULL;
201 va_start(args, fmt);
202 vasprintf(&out, fmt, args);
203 va_end(args);
204 if (out == NULL)
205 fatal("%s: vasprintf failed", __func__);
206
207 debug3("%s length %u%s", out, len, buf == NULL ? " (null)" : "");
208 free(out);
209 if (buf == NULL)
210 return;
211
212 *h = '\0';
213 for (i = j = 0; i < len; i++) {
214 snprintf(h + j, sizeof(h) - j, "%02x", buf[i]);
215 j += 2;
216 if (j >= sizeof(h) - 1 || i == len - 1) {
217 debug3(" %s", h);
218 *h = '\0';
219 j = 0;
220 }
221 }
222}
223
224struct jpake_ctx *
225jpake_new(void)
226{
227 struct jpake_ctx *ret;
228
229 ret = xcalloc(1, sizeof(*ret));
230
231 ret->grp = jpake_default_group();
232
233 ret->s = ret->k = NULL;
234 ret->x1 = ret->x2 = ret->x3 = ret->x4 = NULL;
235 ret->g_x1 = ret->g_x2 = ret->g_x3 = ret->g_x4 = NULL;
236 ret->a = ret->b = NULL;
237
238 ret->client_id = ret->server_id = NULL;
239 ret->h_k_cid_sessid = ret->h_k_sid_sessid = NULL;
240
241 debug3("%s: alloc %p", __func__, ret);
242
243 return ret;
244}
245
246
247void
248jpake_free(struct jpake_ctx *pctx)
249{
250 debug3("%s: free %p", __func__, pctx);
251
252#define JPAKE_BN_CLEAR_FREE(v) \
253 do { \
254 if ((v) != NULL) { \
255 BN_clear_free(v); \
256 (v) = NULL; \
257 } \
258 } while (0)
259#define JPAKE_BUF_CLEAR_FREE(v, l) \
260 do { \
261 if ((v) != NULL) { \
262 bzero((v), (l)); \
263 xfree(v); \
264 (v) = NULL; \
265 (l) = 0; \
266 } \
267 } while (0)
268
269 JPAKE_BN_CLEAR_FREE(pctx->s);
270 JPAKE_BN_CLEAR_FREE(pctx->k);
271 JPAKE_BN_CLEAR_FREE(pctx->x1);
272 JPAKE_BN_CLEAR_FREE(pctx->x2);
273 JPAKE_BN_CLEAR_FREE(pctx->x3);
274 JPAKE_BN_CLEAR_FREE(pctx->x4);
275 JPAKE_BN_CLEAR_FREE(pctx->g_x1);
276 JPAKE_BN_CLEAR_FREE(pctx->g_x2);
277 JPAKE_BN_CLEAR_FREE(pctx->g_x3);
278 JPAKE_BN_CLEAR_FREE(pctx->g_x4);
279 JPAKE_BN_CLEAR_FREE(pctx->a);
280 JPAKE_BN_CLEAR_FREE(pctx->b);
281
282 JPAKE_BUF_CLEAR_FREE(pctx->client_id, pctx->client_id_len);
283 JPAKE_BUF_CLEAR_FREE(pctx->server_id, pctx->server_id_len);
284 JPAKE_BUF_CLEAR_FREE(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
285 JPAKE_BUF_CLEAR_FREE(pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len);
286
287#undef JPAKE_BN_CLEAR_FREE
288#undef JPAKE_BUF_CLEAR_FREE
289
290 bzero(pctx, sizeof(pctx));
291 xfree(pctx);
292}
293
294/* dump entire jpake_ctx. NB. includes private values! */
295void
296jpake_dump(struct jpake_ctx *pctx, const char *fmt, ...)
297{
298 char *out;
299 va_list args;
300
301 out = NULL;
302 va_start(args, fmt);
303 vasprintf(&out, fmt, args);
304 va_end(args);
305 if (out == NULL)
306 fatal("%s: vasprintf failed", __func__);
307
308 debug3("%s: %s (ctx at %p)", __func__, out, pctx);
309 if (pctx == NULL) {
310 free(out);
311 return;
312 }
313
314#define JPAKE_DUMP_BN(a) do { \
315 if ((a) != NULL) \
316 JPAKE_DEBUG_BN(((a), "%s = ", #a)); \
317 } while (0)
318#define JPAKE_DUMP_BUF(a, b) do { \
319 if ((a) != NULL) \
320 JPAKE_DEBUG_BUF((a, b, "%s", #a)); \
321 } while (0)
322
323 JPAKE_DUMP_BN(pctx->s);
324 JPAKE_DUMP_BN(pctx->k);
325 JPAKE_DUMP_BN(pctx->x1);
326 JPAKE_DUMP_BN(pctx->x2);
327 JPAKE_DUMP_BN(pctx->x3);
328 JPAKE_DUMP_BN(pctx->x4);
329 JPAKE_DUMP_BN(pctx->g_x1);
330 JPAKE_DUMP_BN(pctx->g_x2);
331 JPAKE_DUMP_BN(pctx->g_x3);
332 JPAKE_DUMP_BN(pctx->g_x4);
333 JPAKE_DUMP_BN(pctx->a);
334 JPAKE_DUMP_BN(pctx->b);
335
336 JPAKE_DUMP_BUF(pctx->client_id, pctx->client_id_len);
337 JPAKE_DUMP_BUF(pctx->server_id, pctx->server_id_len);
338 JPAKE_DUMP_BUF(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
339 JPAKE_DUMP_BUF(pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len);
340
341 debug3("%s: %s done", __func__, out);
342 free(out);
343}
344
345/* Shared parts of step 1 exchange calculation */
346void
347jpake_step1(struct jpake_group *grp,
348 u_char **id, u_int *id_len,
349 BIGNUM **priv1, BIGNUM **priv2, BIGNUM **g_priv1, BIGNUM **g_priv2,
350 u_char **priv1_proof, u_int *priv1_proof_len,
351 u_char **priv2_proof, u_int *priv2_proof_len)
352{
353 BN_CTX *bn_ctx;
354
355 if ((bn_ctx = BN_CTX_new()) == NULL)
356 fatal("%s: BN_CTX_new", __func__);
357
358 /* Random nonce to prevent replay */
359 *id = xmalloc(KZP_ID_LEN);
360 *id_len = KZP_ID_LEN;
361 arc4random_buf(*id, *id_len);
362
363 /*
364 * x1/x3 is a random element of Zq
365 * x2/x4 is a random element of Z*q
366 * We also exclude [1] from x1/x3 candidates and [0, 1] from
367 * x2/x4 candiates to avoid possible degeneracy (i.e. g^0, g^1).
368 */
369 if ((*priv1 = bn_rand_range_gt_one(grp->q)) == NULL ||
370 (*priv2 = bn_rand_range_gt_one(grp->q)) == NULL)
371 fatal("%s: bn_rand_range_gt_one", __func__);
372
373 /*
374 * client: g_x1 = g^x1 mod p / server: g_x3 = g^x3 mod p
375 * client: g_x2 = g^x2 mod p / server: g_x4 = g^x4 mod p
376 */
377 if ((*g_priv1 = BN_new()) == NULL ||
378 (*g_priv2 = BN_new()) == NULL)
379 fatal("%s: BN_new", __func__);
380 if (BN_mod_exp(*g_priv1, grp->g, *priv1, grp->p, bn_ctx) == -1)
381 fatal("%s: BN_mod_exp", __func__);
382 if (BN_mod_exp(*g_priv2, grp->g, *priv2, grp->p, bn_ctx) == -1)
383 fatal("%s: BN_mod_exp", __func__);
384
385 /* Generate proofs for holding x1/x3 and x2/x4 */
386 if (schnorr_sign(grp->p, grp->q, grp->g,
387 *priv1, *g_priv1, *id, *id_len,
388 priv1_proof, priv1_proof_len) != 0)
389 fatal("%s: schnorr_sign", __func__);
390 if (schnorr_sign(grp->p, grp->q, grp->g,
391 *priv2, *g_priv2, *id, *id_len,
392 priv2_proof, priv2_proof_len) != 0)
393 fatal("%s: schnorr_sign", __func__);
394
395 BN_CTX_free(bn_ctx);
396}
397
398/* Shared parts of step 2 exchange calculation */
399void
400jpake_step2(struct jpake_group *grp, BIGNUM *s,
401 BIGNUM *mypub1, BIGNUM *theirpub1, BIGNUM *theirpub2, BIGNUM *mypriv2,
402 const u_char *theirid, u_int theirid_len,
403 const u_char *myid, u_int myid_len,
404 const u_char *theirpub1_proof, u_int theirpub1_proof_len,
405 const u_char *theirpub2_proof, u_int theirpub2_proof_len,
406 BIGNUM **newpub,
407 u_char **newpub_exponent_proof, u_int *newpub_exponent_proof_len)
408{
409 BN_CTX *bn_ctx;
410 BIGNUM *tmp, *exponent;
411
412 /* Validate peer's step 1 values */
413 if (BN_cmp(theirpub1, BN_value_one()) <= 0)
414 fatal("%s: theirpub1 <= 1", __func__);
415 if (BN_cmp(theirpub2, BN_value_one()) <= 0)
416 fatal("%s: theirpub2 <= 1", __func__);
417
418 if (schnorr_verify(grp->p, grp->q, grp->g, theirpub1,
419 theirid, theirid_len, theirpub1_proof, theirpub1_proof_len) != 1)
420 fatal("%s: schnorr_verify theirpub1 failed", __func__);
421 if (schnorr_verify(grp->p, grp->q, grp->g, theirpub2,
422 theirid, theirid_len, theirpub2_proof, theirpub2_proof_len) != 1)
423 fatal("%s: schnorr_verify theirpub2 failed", __func__);
424
425 if ((bn_ctx = BN_CTX_new()) == NULL)
426 fatal("%s: BN_CTX_new", __func__);
427
428 if ((*newpub = BN_new()) == NULL ||
429 (tmp = BN_new()) == NULL ||
430 (exponent = BN_new()) == NULL)
431 fatal("%s: BN_new", __func__);
432
433 /*
434 * client: exponent = x2 * s mod p
435 * server: exponent = x4 * s mod p
436 */
437 if (BN_mod_mul(exponent, mypriv2, s, grp->q, bn_ctx) != 1)
438 fatal("%s: BN_mod_mul (exponent = mypriv2 * s mod p)",
439 __func__);
440
441 /*
442 * client: tmp = g^(x1 + x3 + x4) mod p
443 * server: tmp = g^(x1 + x2 + x3) mod p
444 */
445 if (BN_mod_mul(tmp, mypub1, theirpub1, grp->p, bn_ctx) != 1)
446 fatal("%s: BN_mod_mul (tmp = mypub1 * theirpub1 mod p)",
447 __func__);
448 if (BN_mod_mul(tmp, tmp, theirpub2, grp->p, bn_ctx) != 1)
449 fatal("%s: BN_mod_mul (tmp = tmp * theirpub2 mod p)", __func__);
450
451 /*
452 * client: a = tmp^exponent = g^((x1+x3+x4) * x2 * s) mod p
453 * server: b = tmp^exponent = g^((x1+x2+x3) * x4 * s) mod p
454 */
455 if (BN_mod_exp(*newpub, tmp, exponent, grp->p, bn_ctx) != 1)
456 fatal("%s: BN_mod_mul (newpub = tmp^exponent mod p)", __func__);
457
458 JPAKE_DEBUG_BN((tmp, "%s: tmp = ", __func__));
459 JPAKE_DEBUG_BN((exponent, "%s: exponent = ", __func__));
460
461 /* Note the generator here is 'tmp', not g */
462 if (schnorr_sign(grp->p, grp->q, tmp, exponent, *newpub,
463 myid, myid_len,
464 newpub_exponent_proof, newpub_exponent_proof_len) != 0)
465 fatal("%s: schnorr_sign newpub", __func__);
466
467 BN_clear_free(tmp); /* XXX stash for later use? */
468 BN_clear_free(exponent); /* XXX stash for later use? (yes, in conf) */
469
470 BN_CTX_free(bn_ctx);
471}
472
473/* Confirmation hash calculation */
474void
475jpake_confirm_hash(const BIGNUM *k,
476 const u_char *endpoint_id, u_int endpoint_id_len,
477 const u_char *sess_id, u_int sess_id_len,
478 u_char **confirm_hash, u_int *confirm_hash_len)
479{
480 Buffer b;
481
482 /*
483 * Calculate confirmation proof:
484 * client: H(k || client_id || session_id)
485 * server: H(k || server_id || session_id)
486 */
487 buffer_init(&b);
488 buffer_put_bignum2(&b, k);
489 buffer_put_string(&b, endpoint_id, endpoint_id_len);
490 buffer_put_string(&b, sess_id, sess_id_len);
491 if (hash_buffer(buffer_ptr(&b), buffer_len(&b), EVP_sha256(),
492 confirm_hash, confirm_hash_len) != 0)
493 fatal("%s: hash_buffer", __func__);
494 buffer_free(&b);
495}
496
497/* Shared parts of key derivation and confirmation calculation */
498void
499jpake_key_confirm(struct jpake_group *grp, BIGNUM *s, BIGNUM *step2_val,
500 BIGNUM *mypriv2, BIGNUM *mypub1, BIGNUM *mypub2,
501 BIGNUM *theirpub1, BIGNUM *theirpub2,
502 const u_char *my_id, u_int my_id_len,
503 const u_char *their_id, u_int their_id_len,
504 const u_char *sess_id, u_int sess_id_len,
505 const u_char *theirpriv2_s_proof, u_int theirpriv2_s_proof_len,
506 BIGNUM **k,
507 u_char **confirm_hash, u_int *confirm_hash_len)
508{
509 BN_CTX *bn_ctx;
510 BIGNUM *tmp;
511
512 if ((bn_ctx = BN_CTX_new()) == NULL)
513 fatal("%s: BN_CTX_new", __func__);
514 if ((tmp = BN_new()) == NULL ||
515 (*k = BN_new()) == NULL)
516 fatal("%s: BN_new", __func__);
517
518 /* Validate step 2 values */
519 if (BN_cmp(step2_val, BN_value_one()) <= 0)
520 fatal("%s: step2_val <= 1", __func__);
521
522 /*
523 * theirpriv2_s_proof is calculated with a different generator:
524 * tmp = g^(mypriv1+mypriv2+theirpub1) = g^mypub1*g^mypub2*g^theirpub1
525 * Calculate it here so we can check the signature.
526 */
527 if (BN_mod_mul(tmp, mypub1, mypub2, grp->p, bn_ctx) != 1)
528 fatal("%s: BN_mod_mul (tmp = mypub1 * mypub2 mod p)", __func__);
529 if (BN_mod_mul(tmp, tmp, theirpub1, grp->p, bn_ctx) != 1)
530 fatal("%s: BN_mod_mul (tmp = tmp * theirpub1 mod p)", __func__);
531
532 JPAKE_DEBUG_BN((tmp, "%s: tmp = ", __func__));
533
534 if (schnorr_verify(grp->p, grp->q, tmp, step2_val,
535 their_id, their_id_len,
536 theirpriv2_s_proof, theirpriv2_s_proof_len) != 1)
537 fatal("%s: schnorr_verify theirpriv2_s_proof failed", __func__);
538
539 /*
540 * Derive shared key:
541 * client: k = (b / g^(x2*x4*s))^x2 = g^((x1+x3)*x2*x4*s)
542 * server: k = (a / g^(x2*x4*s))^x4 = g^((x1+x3)*x2*x4*s)
543 *
544 * Computed as:
545 * client: k = (g_x4^(q - (x2 * s)) * b)^x2 mod p
546 * server: k = (g_x2^(q - (x4 * s)) * b)^x4 mod p
547 */
548 if (BN_mul(tmp, mypriv2, s, bn_ctx) != 1)
549 fatal("%s: BN_mul (tmp = mypriv2 * s)", __func__);
550 if (BN_mod_sub(tmp, grp->q, tmp, grp->q, bn_ctx) != 1)
551 fatal("%s: BN_mod_sub (tmp = q - tmp mod q)", __func__);
552 if (BN_mod_exp(tmp, theirpub2, tmp, grp->p, bn_ctx) != 1)
553 fatal("%s: BN_mod_exp (tmp = theirpub2^tmp) mod p", __func__);
554 if (BN_mod_mul(tmp, tmp, step2_val, grp->p, bn_ctx) != 1)
555 fatal("%s: BN_mod_mul (tmp = tmp * step2_val) mod p", __func__);
556 if (BN_mod_exp(*k, tmp, mypriv2, grp->p, bn_ctx) != 1)
557 fatal("%s: BN_mod_exp (k = tmp^mypriv2) mod p", __func__);
558
559 BN_CTX_free(bn_ctx);
560 BN_clear_free(tmp);
561
562 jpake_confirm_hash(*k, my_id, my_id_len, sess_id, sess_id_len,
563 confirm_hash, confirm_hash_len);
564}
565
566/*
567 * Calculate and check confirmation hash from peer. Returns 1 on success
568 * 0 on failure/mismatch.
569 */
570int
571jpake_check_confirm(const BIGNUM *k,
572 const u_char *peer_id, u_int peer_id_len,
573 const u_char *sess_id, u_int sess_id_len,
574 const u_char *peer_confirm_hash, u_int peer_confirm_hash_len)
575{
576 u_char *expected_confirm_hash;
577 u_int expected_confirm_hash_len;
578 int success = 0;
579
580 /* Calculate and verify expected confirmation hash */
581 jpake_confirm_hash(k, peer_id, peer_id_len, sess_id, sess_id_len,
582 &expected_confirm_hash, &expected_confirm_hash_len);
583
584 JPAKE_DEBUG_BUF((expected_confirm_hash, expected_confirm_hash_len,
585 "%s: expected confirm hash", __func__));
586 JPAKE_DEBUG_BUF((peer_confirm_hash, peer_confirm_hash_len,
587 "%s: received confirm hash", __func__));
588
589 if (peer_confirm_hash_len != expected_confirm_hash_len)
590 error("%s: confirmation length mismatch (my %u them %u)",
591 __func__, expected_confirm_hash_len, peer_confirm_hash_len);
592 else if (memcmp(peer_confirm_hash, expected_confirm_hash,
593 expected_confirm_hash_len) == 0)
594 success = 1;
595 bzero(expected_confirm_hash, expected_confirm_hash_len);
596 xfree(expected_confirm_hash);
597 debug3("%s: success = %d", __func__, success);
598 return success;
599}
600
601/* XXX main() function with tests */
602
603#endif /* JPAKE */
604