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 * $FreeBSD$ 30 */ 31 32 #include <sys/types.h> 33 #include <sys/ioctl.h> 34 #include <assert.h> 35 #include <stdbool.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <netinet/in.h> 40 #include <openssl/err.h> 41 #include <openssl/md5.h> 42 #include <openssl/rand.h> 43 44 #include "iscsid.h" 45 #include "iscsi_proto.h" 46 47 static int 48 login_nsg(const struct pdu *response) 49 { 50 struct iscsi_bhs_login_response *bhslr; 51 52 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 53 54 return (bhslr->bhslr_flags & 0x03); 55 } 56 57 static void 58 login_set_nsg(struct pdu *request, int nsg) 59 { 60 struct iscsi_bhs_login_request *bhslr; 61 62 assert(nsg == BHSLR_STAGE_SECURITY_NEGOTIATION || 63 nsg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION || 64 nsg == BHSLR_STAGE_FULL_FEATURE_PHASE); 65 66 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 67 68 bhslr->bhslr_flags &= 0xFC; 69 bhslr->bhslr_flags |= nsg; 70 } 71 72 static void 73 login_set_csg(struct pdu *request, int csg) 74 { 75 struct iscsi_bhs_login_request *bhslr; 76 77 assert(csg == BHSLR_STAGE_SECURITY_NEGOTIATION || 78 csg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION || 79 csg == BHSLR_STAGE_FULL_FEATURE_PHASE); 80 81 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 82 83 bhslr->bhslr_flags &= 0xF3; 84 bhslr->bhslr_flags |= csg << 2; 85 } 86 87 static const char * 88 login_target_error_str(int class, int detail) 89 { 90 static char msg[128]; 91 92 /* 93 * RFC 3270, 10.13.5. Status-Class and Status-Detail 94 */ 95 switch (class) { 96 case 0x01: 97 switch (detail) { 98 case 0x01: 99 return ("Target moved temporarily"); 100 case 0x02: 101 return ("Target moved permanently"); 102 default: 103 snprintf(msg, sizeof(msg), "unknown redirection; " 104 "Status-Class 0x%x, Status-Detail 0x%x", 105 class, detail); 106 return (msg); 107 } 108 case 0x02: 109 switch (detail) { 110 case 0x00: 111 return ("Initiator error"); 112 case 0x01: 113 return ("Authentication failure"); 114 case 0x02: 115 return ("Authorization failure"); 116 case 0x03: 117 return ("Not found"); 118 case 0x04: 119 return ("Target removed"); 120 case 0x05: 121 return ("Unsupported version"); 122 case 0x06: 123 return ("Too many connections"); 124 case 0x07: 125 return ("Missing parameter"); 126 case 0x08: 127 return ("Can't include in session"); 128 case 0x09: 129 return ("Session type not supported"); 130 case 0x0a: 131 return ("Session does not exist"); 132 case 0x0b: 133 return ("Invalid during login"); 134 default: 135 snprintf(msg, sizeof(msg), "unknown initiator error; " 136 "Status-Class 0x%x, Status-Detail 0x%x", 137 class, detail); 138 return (msg); 139 } 140 case 0x03: 141 switch (detail) { 142 case 0x00: 143 return ("Target error"); 144 case 0x01: 145 return ("Service unavailable"); 146 case 0x02: 147 return ("Out of resources"); 148 default: 149 snprintf(msg, sizeof(msg), "unknown target error; " 150 "Status-Class 0x%x, Status-Detail 0x%x", 151 class, detail); 152 return (msg); 153 } 154 default: 155 snprintf(msg, sizeof(msg), "unknown error; " 156 "Status-Class 0x%x, Status-Detail 0x%x", 157 class, detail); 158 return (msg); 159 } 160 } 161 162 static void 163 kernel_modify(const struct connection *conn, const char *target_address) 164 { 165 struct iscsi_session_modify ism; 166 int error; 167 168 memset(&ism, 0, sizeof(ism)); 169 ism.ism_session_id = conn->conn_session_id; 170 memcpy(&ism.ism_conf, &conn->conn_conf, sizeof(ism.ism_conf)); 171 strlcpy(ism.ism_conf.isc_target_addr, target_address, 172 sizeof(ism.ism_conf.isc_target)); 173 error = ioctl(conn->conn_iscsi_fd, ISCSISMODIFY, &ism); 174 if (error != 0) { 175 log_err(1, "failed to redirect to %s: ISCSISMODIFY", 176 target_address); 177 } 178 } 179 180 /* 181 * XXX: The way it works is suboptimal; what should happen is described 182 * in draft-gilligan-iscsi-fault-tolerance-00. That, however, would 183 * be much more complicated: we would need to keep "dependencies" 184 * for sessions, so that, in case described in draft and using draft 185 * terminology, we would have three sessions: one for discovery, 186 * one for initial target portal, and one for redirect portal. 187 * This would allow us to "backtrack" on connection failure, 188 * as described in draft. 189 */ 190 static void 191 login_handle_redirection(struct connection *conn, struct pdu *response) 192 { 193 struct iscsi_bhs_login_response *bhslr; 194 struct keys *response_keys; 195 const char *target_address; 196 197 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 198 assert (bhslr->bhslr_status_class == 1); 199 200 response_keys = keys_new(); 201 keys_load(response_keys, response); 202 203 target_address = keys_find(response_keys, "TargetAddress"); 204 if (target_address == NULL) 205 log_errx(1, "received redirection without TargetAddress"); 206 if (target_address[0] == '\0') 207 log_errx(1, "received redirection with empty TargetAddress"); 208 if (strlen(target_address) >= 209 sizeof(conn->conn_conf.isc_target_addr) - 1) 210 log_errx(1, "received TargetAddress is too long"); 211 212 log_debugx("received redirection to \"%s\"", target_address); 213 kernel_modify(conn, target_address); 214 } 215 216 static struct pdu * 217 login_receive(struct connection *conn) 218 { 219 struct pdu *response; 220 struct iscsi_bhs_login_response *bhslr; 221 const char *errorstr; 222 static bool initial = true; 223 224 response = pdu_new(conn); 225 pdu_receive(response); 226 if (response->pdu_bhs->bhs_opcode != ISCSI_BHS_OPCODE_LOGIN_RESPONSE) { 227 log_errx(1, "protocol error: received invalid opcode 0x%x", 228 response->pdu_bhs->bhs_opcode); 229 } 230 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 231 /* 232 * XXX: Implement the C flag some day. 233 */ 234 if ((bhslr->bhslr_flags & BHSLR_FLAGS_CONTINUE) != 0) 235 log_errx(1, "received Login PDU with unsupported \"C\" flag"); 236 if (bhslr->bhslr_version_max != 0x00) 237 log_errx(1, "received Login PDU with unsupported " 238 "Version-max 0x%x", bhslr->bhslr_version_max); 239 if (bhslr->bhslr_version_active != 0x00) 240 log_errx(1, "received Login PDU with unsupported " 241 "Version-active 0x%x", bhslr->bhslr_version_active); 242 if (bhslr->bhslr_status_class == 1) { 243 login_handle_redirection(conn, response); 244 log_debugx("redirection handled; exiting"); 245 exit(0); 246 } 247 if (bhslr->bhslr_status_class != 0) { 248 errorstr = login_target_error_str(bhslr->bhslr_status_class, 249 bhslr->bhslr_status_detail); 250 fail(conn, errorstr); 251 log_errx(1, "target returned error: %s", errorstr); 252 } 253 if (initial == false && 254 ntohl(bhslr->bhslr_statsn) != conn->conn_statsn + 1) { 255 /* 256 * It's a warning, not an error, to work around what seems 257 * to be bug in NetBSD iSCSI target. 258 */ 259 log_warnx("received Login PDU with wrong StatSN: " 260 "is %d, should be %d", ntohl(bhslr->bhslr_statsn), 261 conn->conn_statsn + 1); 262 } 263 conn->conn_tsih = ntohs(bhslr->bhslr_tsih); 264 conn->conn_statsn = ntohl(bhslr->bhslr_statsn); 265 266 initial = false; 267 268 return (response); 269 } 270 271 static struct pdu * 272 login_new_request(struct connection *conn, int csg) 273 { 274 struct pdu *request; 275 struct iscsi_bhs_login_request *bhslr; 276 int nsg; 277 278 request = pdu_new(conn); 279 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 280 bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_REQUEST | 281 ISCSI_BHS_OPCODE_IMMEDIATE; 282 283 bhslr->bhslr_flags = BHSLR_FLAGS_TRANSIT; 284 switch (csg) { 285 case BHSLR_STAGE_SECURITY_NEGOTIATION: 286 nsg = BHSLR_STAGE_OPERATIONAL_NEGOTIATION; 287 break; 288 case BHSLR_STAGE_OPERATIONAL_NEGOTIATION: 289 nsg = BHSLR_STAGE_FULL_FEATURE_PHASE; 290 break; 291 default: 292 assert(!"invalid csg"); 293 log_errx(1, "invalid csg %d", csg); 294 } 295 login_set_csg(request, csg); 296 login_set_nsg(request, nsg); 297 298 memcpy(bhslr->bhslr_isid, &conn->conn_isid, sizeof(bhslr->bhslr_isid)); 299 bhslr->bhslr_tsih = htons(conn->conn_tsih); 300 bhslr->bhslr_initiator_task_tag = 0; 301 bhslr->bhslr_cmdsn = 0; 302 bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1); 303 304 return (request); 305 } 306 307 static int 308 login_list_prefers(const char *list, 309 const char *choice1, const char *choice2) 310 { 311 char *tofree, *str, *token; 312 313 tofree = str = checked_strdup(list); 314 315 while ((token = strsep(&str, ",")) != NULL) { 316 if (strcmp(token, choice1) == 0) { 317 free(tofree); 318 return (1); 319 } 320 if (strcmp(token, choice2) == 0) { 321 free(tofree); 322 return (2); 323 } 324 } 325 free(tofree); 326 return (-1); 327 } 328 329 static int 330 login_hex2int(const char hex) 331 { 332 switch (hex) { 333 case '0': 334 return (0x00); 335 case '1': 336 return (0x01); 337 case '2': 338 return (0x02); 339 case '3': 340 return (0x03); 341 case '4': 342 return (0x04); 343 case '5': 344 return (0x05); 345 case '6': 346 return (0x06); 347 case '7': 348 return (0x07); 349 case '8': 350 return (0x08); 351 case '9': 352 return (0x09); 353 case 'a': 354 case 'A': 355 return (0x0a); 356 case 'b': 357 case 'B': 358 return (0x0b); 359 case 'c': 360 case 'C': 361 return (0x0c); 362 case 'd': 363 case 'D': 364 return (0x0d); 365 case 'e': 366 case 'E': 367 return (0x0e); 368 case 'f': 369 case 'F': 370 return (0x0f); 371 default: 372 return (-1); 373 } 374 } 375 376 /* 377 * XXX: Review this _carefully_. 378 */ 379 static int 380 login_hex2bin(const char *hex, char **binp, size_t *bin_lenp) 381 { 382 int i, hex_len, nibble; 383 bool lo = true; /* As opposed to 'hi'. */ 384 char *bin; 385 size_t bin_off, bin_len; 386 387 if (strncasecmp(hex, "0x", strlen("0x")) != 0) { 388 log_warnx("malformed variable, should start with \"0x\""); 389 return (-1); 390 } 391 392 hex += strlen("0x"); 393 hex_len = strlen(hex); 394 if (hex_len < 1) { 395 log_warnx("malformed variable; doesn't contain anything " 396 "but \"0x\""); 397 return (-1); 398 } 399 400 bin_len = hex_len / 2 + hex_len % 2; 401 bin = calloc(bin_len, 1); 402 if (bin == NULL) 403 log_err(1, "calloc"); 404 405 bin_off = bin_len - 1; 406 for (i = hex_len - 1; i >= 0; i--) { 407 nibble = login_hex2int(hex[i]); 408 if (nibble < 0) { 409 log_warnx("malformed variable, invalid char \"%c\"", 410 hex[i]); 411 return (-1); 412 } 413 414 assert(bin_off < bin_len); 415 if (lo) { 416 bin[bin_off] = nibble; 417 lo = false; 418 } else { 419 bin[bin_off] |= nibble << 4; 420 bin_off--; 421 lo = true; 422 } 423 } 424 425 *binp = bin; 426 *bin_lenp = bin_len; 427 return (0); 428 } 429 430 static char * 431 login_bin2hex(const char *bin, size_t bin_len) 432 { 433 unsigned char *hex, *tmp, ch; 434 size_t hex_len; 435 size_t i; 436 437 hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */ 438 hex = malloc(hex_len); 439 if (hex == NULL) 440 log_err(1, "malloc"); 441 442 tmp = hex; 443 tmp += sprintf(tmp, "0x"); 444 for (i = 0; i < bin_len; i++) { 445 ch = bin[i]; 446 tmp += sprintf(tmp, "%02x", ch); 447 } 448 449 return (hex); 450 } 451 452 static void 453 login_compute_md5(const char id, const char *secret, 454 const void *challenge, size_t challenge_len, void *response, 455 size_t response_len) 456 { 457 MD5_CTX ctx; 458 int rv; 459 460 assert(response_len == MD5_DIGEST_LENGTH); 461 462 MD5_Init(&ctx); 463 MD5_Update(&ctx, &id, sizeof(id)); 464 MD5_Update(&ctx, secret, strlen(secret)); 465 MD5_Update(&ctx, challenge, challenge_len); 466 rv = MD5_Final(response, &ctx); 467 if (rv != 1) 468 log_errx(1, "MD5_Final"); 469 } 470 471 static void 472 login_negotiate_key(struct connection *conn, const char *name, 473 const char *value) 474 { 475 int which, tmp; 476 477 if (strcmp(name, "TargetAlias") == 0) { 478 strlcpy(conn->conn_target_alias, value, 479 sizeof(conn->conn_target_alias)); 480 } else if (strcmp(value, "Irrelevant") == 0) { 481 /* Ignore. */ 482 } else if (strcmp(name, "HeaderDigest") == 0) { 483 which = login_list_prefers(value, "CRC32C", "None"); 484 switch (which) { 485 case 1: 486 log_debugx("target prefers CRC32C " 487 "for header digest; we'll use it"); 488 conn->conn_header_digest = CONN_DIGEST_CRC32C; 489 break; 490 case 2: 491 log_debugx("target prefers not to do " 492 "header digest; we'll comply"); 493 break; 494 default: 495 log_warnx("target sent unrecognized " 496 "HeaderDigest value \"%s\"; will use None", value); 497 break; 498 } 499 } else if (strcmp(name, "DataDigest") == 0) { 500 which = login_list_prefers(value, "CRC32C", "None"); 501 switch (which) { 502 case 1: 503 log_debugx("target prefers CRC32C " 504 "for data digest; we'll use it"); 505 conn->conn_data_digest = CONN_DIGEST_CRC32C; 506 break; 507 case 2: 508 log_debugx("target prefers not to do " 509 "data digest; we'll comply"); 510 break; 511 default: 512 log_warnx("target sent unrecognized " 513 "DataDigest value \"%s\"; will use None", value); 514 break; 515 } 516 } else if (strcmp(name, "MaxConnections") == 0) { 517 /* Ignore. */ 518 } else if (strcmp(name, "InitialR2T") == 0) { 519 if (strcmp(value, "Yes") == 0) 520 conn->conn_initial_r2t = true; 521 else 522 conn->conn_initial_r2t = false; 523 } else if (strcmp(name, "ImmediateData") == 0) { 524 if (strcmp(value, "Yes") == 0) 525 conn->conn_immediate_data = true; 526 else 527 conn->conn_immediate_data = false; 528 } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) { 529 tmp = strtoul(value, NULL, 10); 530 if (tmp <= 0) 531 log_errx(1, "received invalid " 532 "MaxRecvDataSegmentLength"); 533 conn->conn_max_data_segment_length = tmp; 534 } else if (strcmp(name, "MaxBurstLength") == 0) { 535 if (conn->conn_immediate_data) { 536 tmp = strtoul(value, NULL, 10); 537 if (tmp <= 0) 538 log_errx(1, "received invalid MaxBurstLength"); 539 conn->conn_max_burst_length = tmp; 540 } 541 } else if (strcmp(name, "FirstBurstLength") == 0) { 542 tmp = strtoul(value, NULL, 10); 543 if (tmp <= 0) 544 log_errx(1, "received invalid FirstBurstLength"); 545 conn->conn_first_burst_length = tmp; 546 } else if (strcmp(name, "DefaultTime2Wait") == 0) { 547 /* Ignore */ 548 } else if (strcmp(name, "DefaultTime2Retain") == 0) { 549 /* Ignore */ 550 } else if (strcmp(name, "MaxOutstandingR2T") == 0) { 551 /* Ignore */ 552 } else if (strcmp(name, "DataPDUInOrder") == 0) { 553 /* Ignore */ 554 } else if (strcmp(name, "DataSequenceInOrder") == 0) { 555 /* Ignore */ 556 } else if (strcmp(name, "ErrorRecoveryLevel") == 0) { 557 /* Ignore */ 558 } else if (strcmp(name, "OFMarker") == 0) { 559 /* Ignore */ 560 } else if (strcmp(name, "IFMarker") == 0) { 561 /* Ignore */ 562 } else if (strcmp(name, "TargetPortalGroupTag") == 0) { 563 /* Ignore */ 564 } else { 565 log_debugx("unknown key \"%s\"; ignoring", name); 566 } 567 } 568 569 static void 570 login_negotiate(struct connection *conn) 571 { 572 struct pdu *request, *response; 573 struct keys *request_keys, *response_keys; 574 struct iscsi_bhs_login_response *bhslr; 575 int i; 576 577 log_debugx("beginning operational parameter negotiation"); 578 request = login_new_request(conn, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 579 request_keys = keys_new(); 580 581 /* 582 * The following keys are irrelevant for discovery sessions. 583 */ 584 if (conn->conn_conf.isc_discovery == 0) { 585 if (conn->conn_conf.isc_header_digest != 0) 586 keys_add(request_keys, "HeaderDigest", "CRC32C"); 587 else 588 keys_add(request_keys, "HeaderDigest", "None"); 589 if (conn->conn_conf.isc_data_digest != 0) 590 keys_add(request_keys, "DataDigest", "CRC32C"); 591 else 592 keys_add(request_keys, "DataDigest", "None"); 593 594 keys_add(request_keys, "ImmediateData", "Yes"); 595 keys_add_int(request_keys, "MaxBurstLength", 596 ISCSI_MAX_DATA_SEGMENT_LENGTH); 597 keys_add_int(request_keys, "FirstBurstLength", 598 ISCSI_MAX_DATA_SEGMENT_LENGTH); 599 keys_add(request_keys, "InitialR2T", "Yes"); 600 } else { 601 keys_add(request_keys, "HeaderDigest", "None"); 602 keys_add(request_keys, "DataDigest", "None"); 603 } 604 605 keys_add_int(request_keys, "MaxRecvDataSegmentLength", 606 ISCSI_MAX_DATA_SEGMENT_LENGTH); 607 keys_add(request_keys, "DefaultTime2Wait", "0"); 608 keys_add(request_keys, "DefaultTime2Retain", "0"); 609 keys_add(request_keys, "ErrorRecoveryLevel", "0"); 610 keys_add(request_keys, "MaxOutstandingR2T", "1"); 611 keys_save(request_keys, request); 612 keys_delete(request_keys); 613 request_keys = NULL; 614 pdu_send(request); 615 pdu_delete(request); 616 request = NULL; 617 618 response = login_receive(conn); 619 response_keys = keys_new(); 620 keys_load(response_keys, response); 621 for (i = 0; i < KEYS_MAX; i++) { 622 if (response_keys->keys_names[i] == NULL) 623 break; 624 625 login_negotiate_key(conn, 626 response_keys->keys_names[i], response_keys->keys_values[i]); 627 } 628 629 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 630 if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0) 631 log_warnx("received final login response " 632 "without the \"T\" flag"); 633 else if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE) 634 log_warnx("received final login response with wrong NSG 0x%x", 635 login_nsg(response)); 636 637 log_debugx("operational parameter negotiation done; " 638 "transitioning to Full Feature phase"); 639 640 keys_delete(response_keys); 641 pdu_delete(response); 642 } 643 644 static void 645 login_send_chap_a(struct connection *conn) 646 { 647 struct pdu *request; 648 struct keys *request_keys; 649 650 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 651 request_keys = keys_new(); 652 keys_add(request_keys, "CHAP_A", "5"); 653 keys_save(request_keys, request); 654 keys_delete(request_keys); 655 pdu_send(request); 656 pdu_delete(request); 657 } 658 659 static void 660 login_send_chap_r(struct pdu *response) 661 { 662 struct connection *conn; 663 struct pdu *request; 664 struct keys *request_keys, *response_keys; 665 const char *chap_a, *chap_c, *chap_i; 666 char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH]; 667 size_t challenge_len; 668 int error, rv; 669 unsigned char id; 670 char *mutual_chap_c, mutual_chap_i[4]; 671 672 /* 673 * As in the rest of the initiator, 'request' means 674 * 'initiator -> target', and 'response' means 'target -> initiator', 675 * 676 * So, here the 'response' from the target is the packet that contains 677 * CHAP challenge; our CHAP response goes into 'request'. 678 */ 679 680 conn = response->pdu_connection; 681 682 response_keys = keys_new(); 683 keys_load(response_keys, response); 684 685 /* 686 * First, compute the response. 687 */ 688 chap_a = keys_find(response_keys, "CHAP_A"); 689 if (chap_a == NULL) 690 log_errx(1, "received CHAP packet without CHAP_A"); 691 chap_c = keys_find(response_keys, "CHAP_C"); 692 if (chap_c == NULL) 693 log_errx(1, "received CHAP packet without CHAP_C"); 694 chap_i = keys_find(response_keys, "CHAP_I"); 695 if (chap_i == NULL) 696 log_errx(1, "received CHAP packet without CHAP_I"); 697 698 if (strcmp(chap_a, "5") != 0) 699 log_errx(1, "received CHAP packet " 700 "with unsupported CHAP_A \"%s\"", chap_a); 701 id = strtoul(chap_i, NULL, 10); 702 error = login_hex2bin(chap_c, &challenge, &challenge_len); 703 if (error != 0) 704 log_errx(1, "received CHAP packet with malformed CHAP_C"); 705 login_compute_md5(id, conn->conn_conf.isc_secret, 706 challenge, challenge_len, response_bin, sizeof(response_bin)); 707 free(challenge); 708 chap_r = login_bin2hex(response_bin, sizeof(response_bin)); 709 710 keys_delete(response_keys); 711 712 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 713 request_keys = keys_new(); 714 keys_add(request_keys, "CHAP_N", conn->conn_conf.isc_user); 715 keys_add(request_keys, "CHAP_R", chap_r); 716 free(chap_r); 717 718 /* 719 * If we want mutual authentication, we're expected to send 720 * our CHAP_I/CHAP_C now. 721 */ 722 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 723 log_debugx("requesting mutual authentication; " 724 "binary challenge size is %zd bytes", 725 sizeof(conn->conn_mutual_challenge)); 726 727 rv = RAND_bytes(conn->conn_mutual_challenge, 728 sizeof(conn->conn_mutual_challenge)); 729 if (rv != 1) { 730 log_errx(1, "RAND_bytes failed: %s", 731 ERR_error_string(ERR_get_error(), NULL)); 732 } 733 rv = RAND_bytes(&conn->conn_mutual_id, 734 sizeof(conn->conn_mutual_id)); 735 if (rv != 1) { 736 log_errx(1, "RAND_bytes failed: %s", 737 ERR_error_string(ERR_get_error(), NULL)); 738 } 739 mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge, 740 sizeof(conn->conn_mutual_challenge)); 741 snprintf(mutual_chap_i, sizeof(mutual_chap_i), 742 "%d", conn->conn_mutual_id); 743 keys_add(request_keys, "CHAP_I", mutual_chap_i); 744 keys_add(request_keys, "CHAP_C", mutual_chap_c); 745 free(mutual_chap_c); 746 } 747 748 keys_save(request_keys, request); 749 keys_delete(request_keys); 750 pdu_send(request); 751 pdu_delete(request); 752 } 753 754 static void 755 login_verify_mutual(const struct pdu *response) 756 { 757 struct connection *conn; 758 struct keys *response_keys; 759 const char *chap_n, *chap_r; 760 char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH]; 761 size_t response_bin_len; 762 int error; 763 764 conn = response->pdu_connection; 765 766 response_keys = keys_new(); 767 keys_load(response_keys, response); 768 769 chap_n = keys_find(response_keys, "CHAP_N"); 770 if (chap_n == NULL) 771 log_errx(1, "received CHAP Response PDU without CHAP_N"); 772 chap_r = keys_find(response_keys, "CHAP_R"); 773 if (chap_r == NULL) 774 log_errx(1, "received CHAP Response PDU without CHAP_R"); 775 error = login_hex2bin(chap_r, &response_bin, &response_bin_len); 776 if (error != 0) 777 log_errx(1, "received CHAP Response PDU with malformed CHAP_R"); 778 779 if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) { 780 fail(conn, "Mutual CHAP failed"); 781 log_errx(1, "mutual CHAP authentication failed: wrong user"); 782 } 783 784 login_compute_md5(conn->conn_mutual_id, 785 conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge, 786 sizeof(conn->conn_mutual_challenge), expected_response_bin, 787 sizeof(expected_response_bin)); 788 789 if (memcmp(response_bin, expected_response_bin, 790 sizeof(expected_response_bin)) != 0) { 791 fail(conn, "Mutual CHAP failed"); 792 log_errx(1, "mutual CHAP authentication failed: wrong secret"); 793 } 794 795 keys_delete(response_keys); 796 free(response_bin); 797 798 log_debugx("mutual CHAP authentication succeeded"); 799 } 800 801 static void 802 login_chap(struct connection *conn) 803 { 804 struct pdu *response; 805 806 log_debugx("beginning CHAP authentication; sending CHAP_A"); 807 login_send_chap_a(conn); 808 809 log_debugx("waiting for CHAP_A/CHAP_C/CHAP_I"); 810 response = login_receive(conn); 811 812 log_debugx("sending CHAP_N/CHAP_R"); 813 login_send_chap_r(response); 814 pdu_delete(response); 815 816 /* 817 * XXX: Make sure this is not susceptible to MITM. 818 */ 819 820 log_debugx("waiting for CHAP result"); 821 response = login_receive(conn); 822 if (conn->conn_conf.isc_mutual_user[0] != '\0') 823 login_verify_mutual(response); 824 pdu_delete(response); 825 826 log_debugx("CHAP authentication done"); 827 } 828 829 void 830 login(struct connection *conn) 831 { 832 struct pdu *request, *response; 833 struct keys *request_keys, *response_keys; 834 struct iscsi_bhs_login_response *bhslr2; 835 const char *auth_method; 836 int i; 837 838 log_debugx("beginning Login phase; sending Login PDU"); 839 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 840 request_keys = keys_new(); 841 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 842 keys_add(request_keys, "AuthMethod", "CHAP"); 843 } else if (conn->conn_conf.isc_user[0] != '\0') { 844 /* 845 * Give target a chance to skip authentication if it 846 * doesn't feel like it. 847 * 848 * None is first, CHAP second; this is to work around 849 * what seems to be LIO (Linux target) bug: otherwise, 850 * if target is configured with no authentication, 851 * and we are configured to authenticate, the target 852 * will erroneously respond with AuthMethod=CHAP 853 * instead of AuthMethod=None, and will subsequently 854 * fail the connection. This usually happens with 855 * Discovery sessions, which default to no authentication. 856 */ 857 keys_add(request_keys, "AuthMethod", "None,CHAP"); 858 } else { 859 keys_add(request_keys, "AuthMethod", "None"); 860 } 861 keys_add(request_keys, "InitiatorName", 862 conn->conn_conf.isc_initiator); 863 if (conn->conn_conf.isc_initiator_alias[0] != '\0') { 864 keys_add(request_keys, "InitiatorAlias", 865 conn->conn_conf.isc_initiator_alias); 866 } 867 if (conn->conn_conf.isc_discovery == 0) { 868 keys_add(request_keys, "SessionType", "Normal"); 869 keys_add(request_keys, 870 "TargetName", conn->conn_conf.isc_target); 871 } else { 872 keys_add(request_keys, "SessionType", "Discovery"); 873 } 874 keys_save(request_keys, request); 875 keys_delete(request_keys); 876 pdu_send(request); 877 pdu_delete(request); 878 879 response = login_receive(conn); 880 881 response_keys = keys_new(); 882 keys_load(response_keys, response); 883 884 for (i = 0; i < KEYS_MAX; i++) { 885 if (response_keys->keys_names[i] == NULL) 886 break; 887 888 /* 889 * Not interested in AuthMethod at this point; we only need 890 * to parse things such as TargetAlias. 891 * 892 * XXX: This is somewhat ugly. We should have a way to apply 893 * all the keys to the session and use that by default 894 * instead of discarding them. 895 */ 896 if (strcmp(response_keys->keys_names[i], "AuthMethod") == 0) 897 continue; 898 899 login_negotiate_key(conn, 900 response_keys->keys_names[i], response_keys->keys_values[i]); 901 } 902 903 bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs; 904 if ((bhslr2->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0 && 905 login_nsg(response) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) { 906 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 907 log_errx(1, "target requested transition " 908 "to operational parameter negotiation, " 909 "but we require mutual CHAP"); 910 } 911 912 log_debugx("target requested transition " 913 "to operational parameter negotiation"); 914 keys_delete(response_keys); 915 pdu_delete(response); 916 login_negotiate(conn); 917 return; 918 } 919 920 auth_method = keys_find(response_keys, "AuthMethod"); 921 if (auth_method == NULL) 922 log_errx(1, "received response without AuthMethod"); 923 if (strcmp(auth_method, "None") == 0) { 924 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 925 log_errx(1, "target does not require authantication, " 926 "but we require mutual CHAP"); 927 } 928 929 log_debugx("target does not require authentication"); 930 keys_delete(response_keys); 931 pdu_delete(response); 932 login_negotiate(conn); 933 return; 934 } 935 936 if (strcmp(auth_method, "CHAP") != 0) { 937 fail(conn, "Unsupported AuthMethod"); 938 log_errx(1, "received response " 939 "with unsupported AuthMethod \"%s\"", auth_method); 940 } 941 942 if (conn->conn_conf.isc_user[0] == '\0' || 943 conn->conn_conf.isc_secret[0] == '\0') { 944 fail(conn, "Authentication required"); 945 log_errx(1, "target requests CHAP authentication, but we don't " 946 "have user and secret"); 947 } 948 949 keys_delete(response_keys); 950 response_keys = NULL; 951 pdu_delete(response); 952 response = NULL; 953 954 login_chap(conn); 955 login_negotiate(conn); 956 } 957