jpake.c revision 189006
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 */ 604 605