login.c revision 262845
1/*- 2 * Copyright (c) 2012 The FreeBSD Foundation 3 * All rights reserved. 4 * 5 * This software was developed by Edward Tomasz Napierala under sponsorship 6 * from the FreeBSD Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD: stable/10/usr.sbin/iscsid/login.c 262845 2014-03-06 11:14:36Z trasz $ 30 */ 31 32#include <sys/types.h> 33#include <assert.h> 34#include <stdbool.h> 35#include <stdio.h> 36#include <stdlib.h> 37#include <string.h> 38#include <netinet/in.h> 39#include <openssl/err.h> 40#include <openssl/md5.h> 41#include <openssl/rand.h> 42 43#include "iscsid.h" 44#include "iscsi_proto.h" 45 46static int 47login_nsg(const struct pdu *response) 48{ 49 struct iscsi_bhs_login_response *bhslr; 50 51 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 52 53 return (bhslr->bhslr_flags & 0x03); 54} 55 56static void 57login_set_nsg(struct pdu *request, int nsg) 58{ 59 struct iscsi_bhs_login_request *bhslr; 60 61 assert(nsg == BHSLR_STAGE_SECURITY_NEGOTIATION || 62 nsg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION || 63 nsg == BHSLR_STAGE_FULL_FEATURE_PHASE); 64 65 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 66 67 bhslr->bhslr_flags &= 0xFC; 68 bhslr->bhslr_flags |= nsg; 69} 70 71static void 72login_set_csg(struct pdu *request, int csg) 73{ 74 struct iscsi_bhs_login_request *bhslr; 75 76 assert(csg == BHSLR_STAGE_SECURITY_NEGOTIATION || 77 csg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION || 78 csg == BHSLR_STAGE_FULL_FEATURE_PHASE); 79 80 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 81 82 bhslr->bhslr_flags &= 0xF3; 83 bhslr->bhslr_flags |= csg << 2; 84} 85 86static const char * 87login_target_error_str(int class, int detail) 88{ 89 static char msg[128]; 90 91 /* 92 * RFC 3270, 10.13.5. Status-Class and Status-Detail 93 */ 94 switch (class) { 95 case 0x01: 96 switch (detail) { 97 case 0x01: 98 return ("Target moved temporarily"); 99 case 0x02: 100 return ("Target moved permanently"); 101 default: 102 snprintf(msg, sizeof(msg), "unknown redirection; " 103 "Status-Class 0x%x, Status-Detail 0x%x", 104 class, detail); 105 return (msg); 106 } 107 case 0x02: 108 switch (detail) { 109 case 0x00: 110 return ("Initiator error"); 111 case 0x01: 112 return ("Authentication failure"); 113 case 0x02: 114 return ("Authorization failure"); 115 case 0x03: 116 return ("Not found"); 117 case 0x04: 118 return ("Target removed"); 119 case 0x05: 120 return ("Unsupported version"); 121 case 0x06: 122 return ("Too many connections"); 123 case 0x07: 124 return ("Missing parameter"); 125 case 0x08: 126 return ("Can't include in session"); 127 case 0x09: 128 return ("Session type not supported"); 129 case 0x0a: 130 return ("Session does not exist"); 131 case 0x0b: 132 return ("Invalid during login"); 133 default: 134 snprintf(msg, sizeof(msg), "unknown initiator error; " 135 "Status-Class 0x%x, Status-Detail 0x%x", 136 class, detail); 137 return (msg); 138 } 139 case 0x03: 140 switch (detail) { 141 case 0x00: 142 return ("Target error"); 143 case 0x01: 144 return ("Service unavailable"); 145 case 0x02: 146 return ("Out of resources"); 147 default: 148 snprintf(msg, sizeof(msg), "unknown target error; " 149 "Status-Class 0x%x, Status-Detail 0x%x", 150 class, detail); 151 return (msg); 152 } 153 default: 154 snprintf(msg, sizeof(msg), "unknown error; " 155 "Status-Class 0x%x, Status-Detail 0x%x", 156 class, detail); 157 return (msg); 158 } 159} 160 161static struct pdu * 162login_receive(struct connection *conn, bool initial) 163{ 164 struct pdu *response; 165 struct iscsi_bhs_login_response *bhslr; 166 const char *errorstr; 167 168 response = pdu_new(conn); 169 pdu_receive(response); 170 if (response->pdu_bhs->bhs_opcode != ISCSI_BHS_OPCODE_LOGIN_RESPONSE) { 171 log_errx(1, "protocol error: received invalid opcode 0x%x", 172 response->pdu_bhs->bhs_opcode); 173 } 174 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 175 /* 176 * XXX: Implement the C flag some day. 177 */ 178 if ((bhslr->bhslr_flags & BHSLR_FLAGS_CONTINUE) != 0) 179 log_errx(1, "received Login PDU with unsupported \"C\" flag"); 180 if (bhslr->bhslr_version_max != 0x00) 181 log_errx(1, "received Login PDU with unsupported " 182 "Version-max 0x%x", bhslr->bhslr_version_max); 183 if (bhslr->bhslr_version_active != 0x00) 184 log_errx(1, "received Login PDU with unsupported " 185 "Version-active 0x%x", bhslr->bhslr_version_active); 186 if (bhslr->bhslr_status_class != 0) { 187 errorstr = login_target_error_str(bhslr->bhslr_status_class, 188 bhslr->bhslr_status_detail); 189 fail(conn, errorstr); 190 log_errx(1, "target returned error: %s", errorstr); 191 } 192 if (initial == false && 193 ntohl(bhslr->bhslr_statsn) != conn->conn_statsn + 1) { 194 /* 195 * It's a warning, not an error, to work around what seems 196 * to be bug in NetBSD iSCSI target. 197 */ 198 log_warnx("received Login PDU with wrong StatSN: " 199 "is %d, should be %d", ntohl(bhslr->bhslr_statsn), 200 conn->conn_statsn + 1); 201 } 202 conn->conn_statsn = ntohl(bhslr->bhslr_statsn); 203 204 return (response); 205} 206 207static struct pdu * 208login_new_request(struct connection *conn) 209{ 210 struct pdu *request; 211 struct iscsi_bhs_login_request *bhslr; 212 213 request = pdu_new(conn); 214 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 215 bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_REQUEST | 216 ISCSI_BHS_OPCODE_IMMEDIATE; 217 bhslr->bhslr_flags = BHSLR_FLAGS_TRANSIT; 218 login_set_csg(request, BHSLR_STAGE_SECURITY_NEGOTIATION); 219 login_set_nsg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 220 memcpy(bhslr->bhslr_isid, &conn->conn_isid, sizeof(bhslr->bhslr_isid)); 221 bhslr->bhslr_initiator_task_tag = 0; 222 bhslr->bhslr_cmdsn = 0; 223 bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1); 224 225 return (request); 226} 227 228static int 229login_list_prefers(const char *list, 230 const char *choice1, const char *choice2) 231{ 232 char *tofree, *str, *token; 233 234 tofree = str = checked_strdup(list); 235 236 while ((token = strsep(&str, ",")) != NULL) { 237 if (strcmp(token, choice1) == 0) { 238 free(tofree); 239 return (1); 240 } 241 if (strcmp(token, choice2) == 0) { 242 free(tofree); 243 return (2); 244 } 245 } 246 free(tofree); 247 return (-1); 248} 249 250static int 251login_hex2int(const char hex) 252{ 253 switch (hex) { 254 case '0': 255 return (0x00); 256 case '1': 257 return (0x01); 258 case '2': 259 return (0x02); 260 case '3': 261 return (0x03); 262 case '4': 263 return (0x04); 264 case '5': 265 return (0x05); 266 case '6': 267 return (0x06); 268 case '7': 269 return (0x07); 270 case '8': 271 return (0x08); 272 case '9': 273 return (0x09); 274 case 'a': 275 case 'A': 276 return (0x0a); 277 case 'b': 278 case 'B': 279 return (0x0b); 280 case 'c': 281 case 'C': 282 return (0x0c); 283 case 'd': 284 case 'D': 285 return (0x0d); 286 case 'e': 287 case 'E': 288 return (0x0e); 289 case 'f': 290 case 'F': 291 return (0x0f); 292 default: 293 return (-1); 294 } 295} 296 297/* 298 * XXX: Review this _carefully_. 299 */ 300static int 301login_hex2bin(const char *hex, char **binp, size_t *bin_lenp) 302{ 303 int i, hex_len, nibble; 304 bool lo = true; /* As opposed to 'hi'. */ 305 char *bin; 306 size_t bin_off, bin_len; 307 308 if (strncasecmp(hex, "0x", strlen("0x")) != 0) { 309 log_warnx("malformed variable, should start with \"0x\""); 310 return (-1); 311 } 312 313 hex += strlen("0x"); 314 hex_len = strlen(hex); 315 if (hex_len < 1) { 316 log_warnx("malformed variable; doesn't contain anything " 317 "but \"0x\""); 318 return (-1); 319 } 320 321 bin_len = hex_len / 2 + hex_len % 2; 322 bin = calloc(bin_len, 1); 323 if (bin == NULL) 324 log_err(1, "calloc"); 325 326 bin_off = bin_len - 1; 327 for (i = hex_len - 1; i >= 0; i--) { 328 nibble = login_hex2int(hex[i]); 329 if (nibble < 0) { 330 log_warnx("malformed variable, invalid char \"%c\"", 331 hex[i]); 332 return (-1); 333 } 334 335 assert(bin_off < bin_len); 336 if (lo) { 337 bin[bin_off] = nibble; 338 lo = false; 339 } else { 340 bin[bin_off] |= nibble << 4; 341 bin_off--; 342 lo = true; 343 } 344 } 345 346 *binp = bin; 347 *bin_lenp = bin_len; 348 return (0); 349} 350 351static char * 352login_bin2hex(const char *bin, size_t bin_len) 353{ 354 unsigned char *hex, *tmp, ch; 355 size_t hex_len; 356 size_t i; 357 358 hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */ 359 hex = malloc(hex_len); 360 if (hex == NULL) 361 log_err(1, "malloc"); 362 363 tmp = hex; 364 tmp += sprintf(tmp, "0x"); 365 for (i = 0; i < bin_len; i++) { 366 ch = bin[i]; 367 tmp += sprintf(tmp, "%02x", ch); 368 } 369 370 return (hex); 371} 372 373static void 374login_compute_md5(const char id, const char *secret, 375 const void *challenge, size_t challenge_len, void *response, 376 size_t response_len) 377{ 378 MD5_CTX ctx; 379 int rv; 380 381 assert(response_len == MD5_DIGEST_LENGTH); 382 383 MD5_Init(&ctx); 384 MD5_Update(&ctx, &id, sizeof(id)); 385 MD5_Update(&ctx, secret, strlen(secret)); 386 MD5_Update(&ctx, challenge, challenge_len); 387 rv = MD5_Final(response, &ctx); 388 if (rv != 1) 389 log_errx(1, "MD5_Final"); 390} 391 392static void 393login_negotiate_key(struct connection *conn, const char *name, 394 const char *value) 395{ 396 int which, tmp; 397 398 if (strcmp(name, "TargetAlias") == 0) { 399 strlcpy(conn->conn_target_alias, value, 400 sizeof(conn->conn_target_alias)); 401 } else if (strcmp(value, "Irrelevant") == 0) { 402 /* Ignore. */ 403 } else if (strcmp(name, "HeaderDigest") == 0) { 404 which = login_list_prefers(value, "CRC32C", "None"); 405 switch (which) { 406 case 1: 407 log_debugx("target prefers CRC32C " 408 "for header digest; we'll use it"); 409 conn->conn_header_digest = CONN_DIGEST_CRC32C; 410 break; 411 case 2: 412 log_debugx("target prefers not to do " 413 "header digest; we'll comply"); 414 break; 415 default: 416 log_warnx("target sent unrecognized " 417 "HeaderDigest value \"%s\"; will use None", value); 418 break; 419 } 420 } else if (strcmp(name, "DataDigest") == 0) { 421 which = login_list_prefers(value, "CRC32C", "None"); 422 switch (which) { 423 case 1: 424 log_debugx("target prefers CRC32C " 425 "for data digest; we'll use it"); 426 conn->conn_data_digest = CONN_DIGEST_CRC32C; 427 break; 428 case 2: 429 log_debugx("target prefers not to do " 430 "data digest; we'll comply"); 431 break; 432 default: 433 log_warnx("target sent unrecognized " 434 "DataDigest value \"%s\"; will use None", value); 435 break; 436 } 437 } else if (strcmp(name, "MaxConnections") == 0) { 438 /* Ignore. */ 439 } else if (strcmp(name, "InitialR2T") == 0) { 440 if (strcmp(value, "Yes") == 0) 441 conn->conn_initial_r2t = true; 442 else 443 conn->conn_initial_r2t = false; 444 } else if (strcmp(name, "ImmediateData") == 0) { 445 if (strcmp(value, "Yes") == 0) 446 conn->conn_immediate_data = true; 447 else 448 conn->conn_immediate_data = false; 449 } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) { 450 tmp = strtoul(value, NULL, 10); 451 if (tmp <= 0) 452 log_errx(1, "received invalid " 453 "MaxRecvDataSegmentLength"); 454 conn->conn_max_data_segment_length = tmp; 455 } else if (strcmp(name, "MaxBurstLength") == 0) { 456 if (conn->conn_immediate_data) { 457 tmp = strtoul(value, NULL, 10); 458 if (tmp <= 0) 459 log_errx(1, "received invalid MaxBurstLength"); 460 conn->conn_max_burst_length = tmp; 461 } 462 } else if (strcmp(name, "FirstBurstLength") == 0) { 463 tmp = strtoul(value, NULL, 10); 464 if (tmp <= 0) 465 log_errx(1, "received invalid FirstBurstLength"); 466 conn->conn_first_burst_length = tmp; 467 } else if (strcmp(name, "DefaultTime2Wait") == 0) { 468 /* Ignore */ 469 } else if (strcmp(name, "DefaultTime2Retain") == 0) { 470 /* Ignore */ 471 } else if (strcmp(name, "MaxOutstandingR2T") == 0) { 472 /* Ignore */ 473 } else if (strcmp(name, "DataPDUInOrder") == 0) { 474 /* Ignore */ 475 } else if (strcmp(name, "DataSequenceInOrder") == 0) { 476 /* Ignore */ 477 } else if (strcmp(name, "ErrorRecoveryLevel") == 0) { 478 /* Ignore */ 479 } else if (strcmp(name, "OFMarker") == 0) { 480 /* Ignore */ 481 } else if (strcmp(name, "IFMarker") == 0) { 482 /* Ignore */ 483 } else if (strcmp(name, "TargetPortalGroupTag") == 0) { 484 /* Ignore */ 485 } else { 486 log_debugx("unknown key \"%s\"; ignoring", name); 487 } 488} 489 490static void 491login_negotiate(struct connection *conn) 492{ 493 struct pdu *request, *response; 494 struct keys *request_keys, *response_keys; 495 struct iscsi_bhs_login_response *bhslr; 496 int i; 497 498 log_debugx("beginning parameter negotiation"); 499 request = login_new_request(conn); 500 login_set_csg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 501 login_set_nsg(request, BHSLR_STAGE_FULL_FEATURE_PHASE); 502 request_keys = keys_new(); 503 504 /* 505 * The following keys are irrelevant for discovery sessions. 506 */ 507 if (conn->conn_conf.isc_discovery == 0) { 508 if (conn->conn_conf.isc_header_digest != 0) 509 keys_add(request_keys, "HeaderDigest", "CRC32C"); 510 else 511 keys_add(request_keys, "HeaderDigest", "None"); 512 if (conn->conn_conf.isc_data_digest != 0) 513 keys_add(request_keys, "DataDigest", "CRC32C"); 514 else 515 keys_add(request_keys, "DataDigest", "None"); 516 517 keys_add(request_keys, "ImmediateData", "Yes"); 518 keys_add_int(request_keys, "MaxBurstLength", 519 ISCSI_MAX_DATA_SEGMENT_LENGTH); 520 keys_add_int(request_keys, "FirstBurstLength", 521 ISCSI_MAX_DATA_SEGMENT_LENGTH); 522 keys_add(request_keys, "InitialR2T", "Yes"); 523 } else { 524 keys_add(request_keys, "HeaderDigest", "None"); 525 keys_add(request_keys, "DataDigest", "None"); 526 } 527 528 keys_add_int(request_keys, "MaxRecvDataSegmentLength", 529 ISCSI_MAX_DATA_SEGMENT_LENGTH); 530 keys_add(request_keys, "DefaultTime2Wait", "0"); 531 keys_add(request_keys, "DefaultTime2Retain", "0"); 532 keys_add(request_keys, "ErrorRecoveryLevel", "0"); 533 keys_add(request_keys, "MaxOutstandingR2T", "1"); 534 keys_save(request_keys, request); 535 keys_delete(request_keys); 536 request_keys = NULL; 537 pdu_send(request); 538 pdu_delete(request); 539 request = NULL; 540 541 response = login_receive(conn, false); 542 response_keys = keys_new(); 543 keys_load(response_keys, response); 544 for (i = 0; i < KEYS_MAX; i++) { 545 if (response_keys->keys_names[i] == NULL) 546 break; 547 548 login_negotiate_key(conn, 549 response_keys->keys_names[i], response_keys->keys_values[i]); 550 } 551 552 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 553 if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0) 554 log_warnx("received final login response " 555 "without the \"T\" flag"); 556 else if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE) 557 log_warnx("received final login response with wrong NSG 0x%x", 558 login_nsg(response)); 559 560 log_debugx("parameter negotiation done; " 561 "transitioning to Full Feature phase"); 562 563 keys_delete(response_keys); 564 pdu_delete(response); 565} 566 567static void 568login_send_chap_a(struct connection *conn) 569{ 570 struct pdu *request; 571 struct keys *request_keys; 572 573 request = login_new_request(conn); 574 request_keys = keys_new(); 575 keys_add(request_keys, "CHAP_A", "5"); 576 keys_save(request_keys, request); 577 keys_delete(request_keys); 578 pdu_send(request); 579 pdu_delete(request); 580} 581 582static void 583login_send_chap_r(struct pdu *response) 584{ 585 struct connection *conn; 586 struct pdu *request; 587 struct keys *request_keys, *response_keys; 588 const char *chap_a, *chap_c, *chap_i; 589 char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH]; 590 size_t challenge_len; 591 int error, rv; 592 unsigned char id; 593 char *mutual_chap_c, mutual_chap_i[4]; 594 595 /* 596 * As in the rest of the initiator, 'request' means 597 * 'initiator -> target', and 'response' means 'target -> initiator', 598 * 599 * So, here the 'response' from the target is the packet that contains 600 * CHAP challenge; our CHAP response goes into 'request'. 601 */ 602 603 conn = response->pdu_connection; 604 605 response_keys = keys_new(); 606 keys_load(response_keys, response); 607 608 /* 609 * First, compute the response. 610 */ 611 chap_a = keys_find(response_keys, "CHAP_A"); 612 if (chap_a == NULL) 613 log_errx(1, "received CHAP packet without CHAP_A"); 614 chap_c = keys_find(response_keys, "CHAP_C"); 615 if (chap_c == NULL) 616 log_errx(1, "received CHAP packet without CHAP_C"); 617 chap_i = keys_find(response_keys, "CHAP_I"); 618 if (chap_i == NULL) 619 log_errx(1, "received CHAP packet without CHAP_I"); 620 621 if (strcmp(chap_a, "5") != 0) 622 log_errx(1, "received CHAP packet " 623 "with unsupported CHAP_A \"%s\"", chap_a); 624 id = strtoul(chap_i, NULL, 10); 625 error = login_hex2bin(chap_c, &challenge, &challenge_len); 626 if (error != 0) 627 log_errx(1, "received CHAP packet with malformed CHAP_C"); 628 login_compute_md5(id, conn->conn_conf.isc_secret, 629 challenge, challenge_len, response_bin, sizeof(response_bin)); 630 free(challenge); 631 chap_r = login_bin2hex(response_bin, sizeof(response_bin)); 632 633 keys_delete(response_keys); 634 635 request = login_new_request(conn); 636 request_keys = keys_new(); 637 keys_add(request_keys, "CHAP_N", conn->conn_conf.isc_user); 638 keys_add(request_keys, "CHAP_R", chap_r); 639 free(chap_r); 640 641 /* 642 * If we want mutual authentication, we're expected to send 643 * our CHAP_I/CHAP_C now. 644 */ 645 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 646 log_debugx("requesting mutual authentication; " 647 "binary challenge size is %zd bytes", 648 sizeof(conn->conn_mutual_challenge)); 649 650 rv = RAND_bytes(conn->conn_mutual_challenge, 651 sizeof(conn->conn_mutual_challenge)); 652 if (rv != 1) { 653 log_errx(1, "RAND_bytes failed: %s", 654 ERR_error_string(ERR_get_error(), NULL)); 655 } 656 rv = RAND_bytes(&conn->conn_mutual_id, 657 sizeof(conn->conn_mutual_id)); 658 if (rv != 1) { 659 log_errx(1, "RAND_bytes failed: %s", 660 ERR_error_string(ERR_get_error(), NULL)); 661 } 662 mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge, 663 sizeof(conn->conn_mutual_challenge)); 664 snprintf(mutual_chap_i, sizeof(mutual_chap_i), 665 "%d", conn->conn_mutual_id); 666 keys_add(request_keys, "CHAP_I", mutual_chap_i); 667 keys_add(request_keys, "CHAP_C", mutual_chap_c); 668 free(mutual_chap_c); 669 } 670 671 keys_save(request_keys, request); 672 keys_delete(request_keys); 673 pdu_send(request); 674 pdu_delete(request); 675} 676 677static void 678login_verify_mutual(const struct pdu *response) 679{ 680 struct connection *conn; 681 struct keys *response_keys; 682 const char *chap_n, *chap_r; 683 char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH]; 684 size_t response_bin_len; 685 int error; 686 687 conn = response->pdu_connection; 688 689 response_keys = keys_new(); 690 keys_load(response_keys, response); 691 692 chap_n = keys_find(response_keys, "CHAP_N"); 693 if (chap_n == NULL) 694 log_errx(1, "received CHAP Response PDU without CHAP_N"); 695 chap_r = keys_find(response_keys, "CHAP_R"); 696 if (chap_r == NULL) 697 log_errx(1, "received CHAP Response PDU without CHAP_R"); 698 error = login_hex2bin(chap_r, &response_bin, &response_bin_len); 699 if (error != 0) 700 log_errx(1, "received CHAP Response PDU with malformed CHAP_R"); 701 702 if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) { 703 fail(conn, "Mutual CHAP failed"); 704 log_errx(1, "mutual CHAP authentication failed: wrong user"); 705 } 706 707 login_compute_md5(conn->conn_mutual_id, 708 conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge, 709 sizeof(conn->conn_mutual_challenge), expected_response_bin, 710 sizeof(expected_response_bin)); 711 712 if (memcmp(response_bin, expected_response_bin, 713 sizeof(expected_response_bin)) != 0) { 714 fail(conn, "Mutual CHAP failed"); 715 log_errx(1, "mutual CHAP authentication failed: wrong secret"); 716 } 717 718 keys_delete(response_keys); 719 free(response_bin); 720 721 log_debugx("mutual CHAP authentication succeeded"); 722} 723 724static void 725login_chap(struct connection *conn) 726{ 727 struct pdu *response; 728 729 log_debugx("beginning CHAP authentication; sending CHAP_A"); 730 login_send_chap_a(conn); 731 732 log_debugx("waiting for CHAP_A/CHAP_C/CHAP_I"); 733 response = login_receive(conn, false); 734 735 log_debugx("sending CHAP_N/CHAP_R"); 736 login_send_chap_r(response); 737 pdu_delete(response); 738 739 /* 740 * XXX: Make sure this is not susceptible to MITM. 741 */ 742 743 log_debugx("waiting for CHAP result"); 744 response = login_receive(conn, false); 745 if (conn->conn_conf.isc_mutual_user[0] != '\0') 746 login_verify_mutual(response); 747 pdu_delete(response); 748 749 log_debugx("CHAP authentication done"); 750} 751 752static void 753login_create_isid(struct connection *conn) 754{ 755 int rv; 756 757 /* 758 * RFC 3720, 10.12.5: 10b, "Random" ISID. 759 * 760 */ 761 conn->conn_isid[0] = 0x80; 762 763 rv = RAND_bytes(&conn->conn_isid[1], 3); 764 if (rv != 1) { 765 log_errx(1, "RAND_bytes failed: %s", 766 ERR_error_string(ERR_get_error(), NULL)); 767 } 768} 769 770void 771login(struct connection *conn) 772{ 773 struct pdu *request, *response; 774 struct keys *request_keys, *response_keys; 775 struct iscsi_bhs_login_request *bhslr; 776 struct iscsi_bhs_login_response *bhslr2; 777 const char *auth_method; 778 int i; 779 780 login_create_isid(conn); 781 782 log_debugx("beginning Login phase; sending Login PDU"); 783 request = login_new_request(conn); 784 785 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 786 bhslr->bhslr_flags |= BHSLR_FLAGS_TRANSIT; 787 788 request_keys = keys_new(); 789 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 790 keys_add(request_keys, "AuthMethod", "CHAP"); 791 } else if (conn->conn_conf.isc_user[0] != '\0') { 792 /* 793 * Give target a chance to skip authentication if it 794 * doesn't feel like it. 795 * 796 * None is first, CHAP second; this is to work around 797 * what seems to be LIO (Linux target) bug: otherwise, 798 * if target is configured with no authentication, 799 * and we are configured to authenticate, the target 800 * will erroneously respond with AuthMethod=CHAP 801 * instead of AuthMethod=None, and will subsequently 802 * fail the connection. This usually happens with 803 * Discovery sessions, which default to no authentication. 804 */ 805 keys_add(request_keys, "AuthMethod", "None,CHAP"); 806 } else { 807 keys_add(request_keys, "AuthMethod", "None"); 808 } 809 keys_add(request_keys, "InitiatorName", 810 conn->conn_conf.isc_initiator); 811 if (conn->conn_conf.isc_initiator_alias[0] != '\0') { 812 keys_add(request_keys, "InitiatorAlias", 813 conn->conn_conf.isc_initiator_alias); 814 } 815 if (conn->conn_conf.isc_discovery == 0) { 816 keys_add(request_keys, "SessionType", "Normal"); 817 keys_add(request_keys, 818 "TargetName", conn->conn_conf.isc_target); 819 } else { 820 keys_add(request_keys, "SessionType", "Discovery"); 821 } 822 keys_save(request_keys, request); 823 keys_delete(request_keys); 824 pdu_send(request); 825 pdu_delete(request); 826 827 response = login_receive(conn, true); 828 829 response_keys = keys_new(); 830 keys_load(response_keys, response); 831 832 for (i = 0; i < KEYS_MAX; i++) { 833 if (response_keys->keys_names[i] == NULL) 834 break; 835 836 /* 837 * Not interested in AuthMethod at this point; we only need 838 * to parse things such as TargetAlias. 839 * 840 * XXX: This is somewhat ugly. We should have a way to apply 841 * all the keys to the session and use that by default 842 * instead of discarding them. 843 */ 844 if (strcmp(response_keys->keys_names[i], "AuthMethod") == 0) 845 continue; 846 847 login_negotiate_key(conn, 848 response_keys->keys_names[i], response_keys->keys_values[i]); 849 } 850 851 bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs; 852 if ((bhslr2->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0 && 853 login_nsg(response) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) { 854 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 855 log_errx(1, "target requested transition " 856 "to operational negotiation, but we require " 857 "mutual CHAP"); 858 } 859 860 log_debugx("target requested transition " 861 "to operational negotiation"); 862 keys_delete(response_keys); 863 pdu_delete(response); 864 login_negotiate(conn); 865 return; 866 } 867 868 auth_method = keys_find(response_keys, "AuthMethod"); 869 if (auth_method == NULL) 870 log_errx(1, "received response without AuthMethod"); 871 if (strcmp(auth_method, "None") == 0) { 872 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 873 log_errx(1, "target does not require authantication, " 874 "but we require mutual CHAP"); 875 } 876 877 log_debugx("target does not require authentication"); 878 keys_delete(response_keys); 879 pdu_delete(response); 880 login_negotiate(conn); 881 return; 882 } 883 884 if (strcmp(auth_method, "CHAP") != 0) { 885 fail(conn, "Unsupported AuthMethod"); 886 log_errx(1, "received response " 887 "with unsupported AuthMethod \"%s\"", auth_method); 888 } 889 890 if (conn->conn_conf.isc_user[0] == '\0' || 891 conn->conn_conf.isc_secret[0] == '\0') { 892 fail(conn, "Authentication required"); 893 log_errx(1, "target requests CHAP authentication, but we don't " 894 "have user and secret"); 895 } 896 897 keys_delete(response_keys); 898 response_keys = NULL; 899 pdu_delete(response); 900 response = NULL; 901 902 login_chap(conn); 903 login_negotiate(conn); 904} 905