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 */ 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD$"); 33 34#include <sys/types.h> 35#include <sys/ioctl.h> 36#include <assert.h> 37#include <stdbool.h> 38#include <stdio.h> 39#include <stdlib.h> 40#include <string.h> 41#include <netinet/in.h> 42#include <openssl/err.h> 43#include <openssl/md5.h> 44#include <openssl/rand.h> 45 46#include "iscsid.h" 47#include "iscsi_proto.h" 48 49static int 50login_nsg(const struct pdu *response) 51{ 52 struct iscsi_bhs_login_response *bhslr; 53 54 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 55 56 return (bhslr->bhslr_flags & 0x03); 57} 58 59static void 60login_set_nsg(struct pdu *request, int nsg) 61{ 62 struct iscsi_bhs_login_request *bhslr; 63 64 assert(nsg == BHSLR_STAGE_SECURITY_NEGOTIATION || 65 nsg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION || 66 nsg == BHSLR_STAGE_FULL_FEATURE_PHASE); 67 68 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 69 70 bhslr->bhslr_flags &= 0xFC; 71 bhslr->bhslr_flags |= nsg; 72} 73 74static void 75login_set_csg(struct pdu *request, int csg) 76{ 77 struct iscsi_bhs_login_request *bhslr; 78 79 assert(csg == BHSLR_STAGE_SECURITY_NEGOTIATION || 80 csg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION || 81 csg == BHSLR_STAGE_FULL_FEATURE_PHASE); 82 83 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 84 85 bhslr->bhslr_flags &= 0xF3; 86 bhslr->bhslr_flags |= csg << 2; 87} 88 89static const char * 90login_target_error_str(int class, int detail) 91{ 92 static char msg[128]; 93 94 /* 95 * RFC 3270, 10.13.5. Status-Class and Status-Detail 96 */ 97 switch (class) { 98 case 0x01: 99 switch (detail) { 100 case 0x01: 101 return ("Target moved temporarily"); 102 case 0x02: 103 return ("Target moved permanently"); 104 default: 105 snprintf(msg, sizeof(msg), "unknown redirection; " 106 "Status-Class 0x%x, Status-Detail 0x%x", 107 class, detail); 108 return (msg); 109 } 110 case 0x02: 111 switch (detail) { 112 case 0x00: 113 return ("Initiator error"); 114 case 0x01: 115 return ("Authentication failure"); 116 case 0x02: 117 return ("Authorization failure"); 118 case 0x03: 119 return ("Not found"); 120 case 0x04: 121 return ("Target removed"); 122 case 0x05: 123 return ("Unsupported version"); 124 case 0x06: 125 return ("Too many connections"); 126 case 0x07: 127 return ("Missing parameter"); 128 case 0x08: 129 return ("Can't include in session"); 130 case 0x09: 131 return ("Session type not supported"); 132 case 0x0a: 133 return ("Session does not exist"); 134 case 0x0b: 135 return ("Invalid during login"); 136 default: 137 snprintf(msg, sizeof(msg), "unknown initiator error; " 138 "Status-Class 0x%x, Status-Detail 0x%x", 139 class, detail); 140 return (msg); 141 } 142 case 0x03: 143 switch (detail) { 144 case 0x00: 145 return ("Target error"); 146 case 0x01: 147 return ("Service unavailable"); 148 case 0x02: 149 return ("Out of resources"); 150 default: 151 snprintf(msg, sizeof(msg), "unknown target error; " 152 "Status-Class 0x%x, Status-Detail 0x%x", 153 class, detail); 154 return (msg); 155 } 156 default: 157 snprintf(msg, sizeof(msg), "unknown error; " 158 "Status-Class 0x%x, Status-Detail 0x%x", 159 class, detail); 160 return (msg); 161 } 162} 163 164static void 165kernel_modify(const struct connection *conn, const char *target_address) 166{ 167 struct iscsi_session_modify ism; 168 int error; 169 170 memset(&ism, 0, sizeof(ism)); 171 ism.ism_session_id = conn->conn_session_id; 172 memcpy(&ism.ism_conf, &conn->conn_conf, sizeof(ism.ism_conf)); 173 strlcpy(ism.ism_conf.isc_target_addr, target_address, 174 sizeof(ism.ism_conf.isc_target)); 175 error = ioctl(conn->conn_iscsi_fd, ISCSISMODIFY, &ism); 176 if (error != 0) { 177 log_err(1, "failed to redirect to %s: ISCSISMODIFY", 178 target_address); 179 } 180} 181 182/* 183 * XXX: The way it works is suboptimal; what should happen is described 184 * in draft-gilligan-iscsi-fault-tolerance-00. That, however, would 185 * be much more complicated: we would need to keep "dependencies" 186 * for sessions, so that, in case described in draft and using draft 187 * terminology, we would have three sessions: one for discovery, 188 * one for initial target portal, and one for redirect portal. 189 * This would allow us to "backtrack" on connection failure, 190 * as described in draft. 191 */ 192static void 193login_handle_redirection(struct connection *conn, struct pdu *response) 194{ 195 struct iscsi_bhs_login_response *bhslr; 196 struct keys *response_keys; 197 const char *target_address; 198 199 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 200 assert (bhslr->bhslr_status_class == 1); 201 202 response_keys = keys_new(); 203 keys_load(response_keys, response); 204 205 target_address = keys_find(response_keys, "TargetAddress"); 206 if (target_address == NULL) 207 log_errx(1, "received redirection without TargetAddress"); 208 if (target_address[0] == '\0') 209 log_errx(1, "received redirection with empty TargetAddress"); 210 if (strlen(target_address) >= 211 sizeof(conn->conn_conf.isc_target_addr) - 1) 212 log_errx(1, "received TargetAddress is too long"); 213 214 log_debugx("received redirection to \"%s\"", target_address); 215 kernel_modify(conn, target_address); 216} 217 218static struct pdu * 219login_receive(struct connection *conn) 220{ 221 struct pdu *response; 222 struct iscsi_bhs_login_response *bhslr; 223 const char *errorstr; 224 static bool initial = true; 225 226 response = pdu_new(conn); 227 pdu_receive(response); 228 if (response->pdu_bhs->bhs_opcode != ISCSI_BHS_OPCODE_LOGIN_RESPONSE) { 229 log_errx(1, "protocol error: received invalid opcode 0x%x", 230 response->pdu_bhs->bhs_opcode); 231 } 232 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 233 /* 234 * XXX: Implement the C flag some day. 235 */ 236 if ((bhslr->bhslr_flags & BHSLR_FLAGS_CONTINUE) != 0) 237 log_errx(1, "received Login PDU with unsupported \"C\" flag"); 238 if (bhslr->bhslr_version_max != 0x00) 239 log_errx(1, "received Login PDU with unsupported " 240 "Version-max 0x%x", bhslr->bhslr_version_max); 241 if (bhslr->bhslr_version_active != 0x00) 242 log_errx(1, "received Login PDU with unsupported " 243 "Version-active 0x%x", bhslr->bhslr_version_active); 244 if (bhslr->bhslr_status_class == 1) { 245 login_handle_redirection(conn, response); 246 log_debugx("redirection handled; exiting"); 247 exit(0); 248 } 249 if (bhslr->bhslr_status_class != 0) { 250 errorstr = login_target_error_str(bhslr->bhslr_status_class, 251 bhslr->bhslr_status_detail); 252 fail(conn, errorstr); 253 log_errx(1, "target returned error: %s", errorstr); 254 } 255 if (initial == false && 256 ntohl(bhslr->bhslr_statsn) != conn->conn_statsn + 1) { 257 /* 258 * It's a warning, not an error, to work around what seems 259 * to be bug in NetBSD iSCSI target. 260 */ 261 log_warnx("received Login PDU with wrong StatSN: " 262 "is %d, should be %d", ntohl(bhslr->bhslr_statsn), 263 conn->conn_statsn + 1); 264 } 265 conn->conn_tsih = ntohs(bhslr->bhslr_tsih); 266 conn->conn_statsn = ntohl(bhslr->bhslr_statsn); 267 268 initial = false; 269 270 return (response); 271} 272 273static struct pdu * 274login_new_request(struct connection *conn, int csg) 275{ 276 struct pdu *request; 277 struct iscsi_bhs_login_request *bhslr; 278 int nsg; 279 280 request = pdu_new(conn); 281 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 282 bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_REQUEST | 283 ISCSI_BHS_OPCODE_IMMEDIATE; 284 285 bhslr->bhslr_flags = BHSLR_FLAGS_TRANSIT; 286 switch (csg) { 287 case BHSLR_STAGE_SECURITY_NEGOTIATION: 288 nsg = BHSLR_STAGE_OPERATIONAL_NEGOTIATION; 289 break; 290 case BHSLR_STAGE_OPERATIONAL_NEGOTIATION: 291 nsg = BHSLR_STAGE_FULL_FEATURE_PHASE; 292 break; 293 default: 294 assert(!"invalid csg"); 295 log_errx(1, "invalid csg %d", csg); 296 } 297 login_set_csg(request, csg); 298 login_set_nsg(request, nsg); 299 300 memcpy(bhslr->bhslr_isid, &conn->conn_isid, sizeof(bhslr->bhslr_isid)); 301 bhslr->bhslr_tsih = htons(conn->conn_tsih); 302 bhslr->bhslr_initiator_task_tag = 0; 303 bhslr->bhslr_cmdsn = 0; 304 bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1); 305 306 return (request); 307} 308 309static int 310login_list_prefers(const char *list, 311 const char *choice1, const char *choice2) 312{ 313 char *tofree, *str, *token; 314 315 tofree = str = checked_strdup(list); 316 317 while ((token = strsep(&str, ",")) != NULL) { 318 if (strcmp(token, choice1) == 0) { 319 free(tofree); 320 return (1); 321 } 322 if (strcmp(token, choice2) == 0) { 323 free(tofree); 324 return (2); 325 } 326 } 327 free(tofree); 328 return (-1); 329} 330 331static int 332login_hex2int(const char hex) 333{ 334 switch (hex) { 335 case '0': 336 return (0x00); 337 case '1': 338 return (0x01); 339 case '2': 340 return (0x02); 341 case '3': 342 return (0x03); 343 case '4': 344 return (0x04); 345 case '5': 346 return (0x05); 347 case '6': 348 return (0x06); 349 case '7': 350 return (0x07); 351 case '8': 352 return (0x08); 353 case '9': 354 return (0x09); 355 case 'a': 356 case 'A': 357 return (0x0a); 358 case 'b': 359 case 'B': 360 return (0x0b); 361 case 'c': 362 case 'C': 363 return (0x0c); 364 case 'd': 365 case 'D': 366 return (0x0d); 367 case 'e': 368 case 'E': 369 return (0x0e); 370 case 'f': 371 case 'F': 372 return (0x0f); 373 default: 374 return (-1); 375 } 376} 377 378/* 379 * XXX: Review this _carefully_. 380 */ 381static int 382login_hex2bin(const char *hex, char **binp, size_t *bin_lenp) 383{ 384 int i, hex_len, nibble; 385 bool lo = true; /* As opposed to 'hi'. */ 386 char *bin; 387 size_t bin_off, bin_len; 388 389 if (strncasecmp(hex, "0x", strlen("0x")) != 0) { 390 log_warnx("malformed variable, should start with \"0x\""); 391 return (-1); 392 } 393 394 hex += strlen("0x"); 395 hex_len = strlen(hex); 396 if (hex_len < 1) { 397 log_warnx("malformed variable; doesn't contain anything " 398 "but \"0x\""); 399 return (-1); 400 } 401 402 bin_len = hex_len / 2 + hex_len % 2; 403 bin = calloc(bin_len, 1); 404 if (bin == NULL) 405 log_err(1, "calloc"); 406 407 bin_off = bin_len - 1; 408 for (i = hex_len - 1; i >= 0; i--) { 409 nibble = login_hex2int(hex[i]); 410 if (nibble < 0) { 411 log_warnx("malformed variable, invalid char \"%c\"", 412 hex[i]); 413 return (-1); 414 } 415 416 assert(bin_off < bin_len); 417 if (lo) { 418 bin[bin_off] = nibble; 419 lo = false; 420 } else { 421 bin[bin_off] |= nibble << 4; 422 bin_off--; 423 lo = true; 424 } 425 } 426 427 *binp = bin; 428 *bin_lenp = bin_len; 429 return (0); 430} 431 432static char * 433login_bin2hex(const char *bin, size_t bin_len) 434{ 435 unsigned char *hex, *tmp, ch; 436 size_t hex_len; 437 size_t i; 438 439 hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */ 440 hex = malloc(hex_len); 441 if (hex == NULL) 442 log_err(1, "malloc"); 443 444 tmp = hex; 445 tmp += sprintf(tmp, "0x"); 446 for (i = 0; i < bin_len; i++) { 447 ch = bin[i]; 448 tmp += sprintf(tmp, "%02x", ch); 449 } 450 451 return (hex); 452} 453 454static void 455login_compute_md5(const char id, const char *secret, 456 const void *challenge, size_t challenge_len, void *response, 457 size_t response_len) 458{ 459 MD5_CTX ctx; 460 int rv; 461 462 assert(response_len == MD5_DIGEST_LENGTH); 463 464 MD5_Init(&ctx); 465 MD5_Update(&ctx, &id, sizeof(id)); 466 MD5_Update(&ctx, secret, strlen(secret)); 467 MD5_Update(&ctx, challenge, challenge_len); 468 rv = MD5_Final(response, &ctx); 469 if (rv != 1) 470 log_errx(1, "MD5_Final"); 471} 472 473static void 474login_negotiate_key(struct connection *conn, const char *name, 475 const char *value) 476{ 477 int which, tmp; 478 479 if (strcmp(name, "TargetAlias") == 0) { 480 strlcpy(conn->conn_target_alias, value, 481 sizeof(conn->conn_target_alias)); 482 } else if (strcmp(value, "Irrelevant") == 0) { 483 /* Ignore. */ 484 } else if (strcmp(name, "HeaderDigest") == 0) { 485 which = login_list_prefers(value, "CRC32C", "None"); 486 switch (which) { 487 case 1: 488 log_debugx("target prefers CRC32C " 489 "for header digest; we'll use it"); 490 conn->conn_header_digest = CONN_DIGEST_CRC32C; 491 break; 492 case 2: 493 log_debugx("target prefers not to do " 494 "header digest; we'll comply"); 495 break; 496 default: 497 log_warnx("target sent unrecognized " 498 "HeaderDigest value \"%s\"; will use None", value); 499 break; 500 } 501 } else if (strcmp(name, "DataDigest") == 0) { 502 which = login_list_prefers(value, "CRC32C", "None"); 503 switch (which) { 504 case 1: 505 log_debugx("target prefers CRC32C " 506 "for data digest; we'll use it"); 507 conn->conn_data_digest = CONN_DIGEST_CRC32C; 508 break; 509 case 2: 510 log_debugx("target prefers not to do " 511 "data digest; we'll comply"); 512 break; 513 default: 514 log_warnx("target sent unrecognized " 515 "DataDigest value \"%s\"; will use None", value); 516 break; 517 } 518 } else if (strcmp(name, "MaxConnections") == 0) { 519 /* Ignore. */ 520 } else if (strcmp(name, "InitialR2T") == 0) { 521 if (strcmp(value, "Yes") == 0) 522 conn->conn_initial_r2t = true; 523 else 524 conn->conn_initial_r2t = false; 525 } else if (strcmp(name, "ImmediateData") == 0) { 526 if (strcmp(value, "Yes") == 0) 527 conn->conn_immediate_data = true; 528 else 529 conn->conn_immediate_data = false; 530 } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) { 531 tmp = strtoul(value, NULL, 10); 532 if (tmp <= 0) 533 log_errx(1, "received invalid " 534 "MaxRecvDataSegmentLength"); 535 conn->conn_max_data_segment_length = tmp; 536 } else if (strcmp(name, "MaxBurstLength") == 0) { 537 if (conn->conn_immediate_data) { 538 tmp = strtoul(value, NULL, 10); 539 if (tmp <= 0) 540 log_errx(1, "received invalid MaxBurstLength"); 541 conn->conn_max_burst_length = tmp; 542 } 543 } else if (strcmp(name, "FirstBurstLength") == 0) { 544 tmp = strtoul(value, NULL, 10); 545 if (tmp <= 0) 546 log_errx(1, "received invalid FirstBurstLength"); 547 conn->conn_first_burst_length = tmp; 548 } else if (strcmp(name, "DefaultTime2Wait") == 0) { 549 /* Ignore */ 550 } else if (strcmp(name, "DefaultTime2Retain") == 0) { 551 /* Ignore */ 552 } else if (strcmp(name, "MaxOutstandingR2T") == 0) { 553 /* Ignore */ 554 } else if (strcmp(name, "DataPDUInOrder") == 0) { 555 /* Ignore */ 556 } else if (strcmp(name, "DataSequenceInOrder") == 0) { 557 /* Ignore */ 558 } else if (strcmp(name, "ErrorRecoveryLevel") == 0) { 559 /* Ignore */ 560 } else if (strcmp(name, "OFMarker") == 0) { 561 /* Ignore */ 562 } else if (strcmp(name, "IFMarker") == 0) { 563 /* Ignore */ 564 } else if (strcmp(name, "TargetPortalGroupTag") == 0) { 565 /* Ignore */ 566 } else { 567 log_debugx("unknown key \"%s\"; ignoring", name); 568 } 569} 570 571static void 572login_negotiate(struct connection *conn) 573{ 574 struct pdu *request, *response; 575 struct keys *request_keys, *response_keys; 576 struct iscsi_bhs_login_response *bhslr; 577 int i, nrequests = 0; 578 579 log_debugx("beginning operational parameter negotiation"); 580 request = login_new_request(conn, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 581 request_keys = keys_new(); 582 583 /* 584 * The following keys are irrelevant for discovery sessions. 585 */ 586 if (conn->conn_conf.isc_discovery == 0) { 587 if (conn->conn_conf.isc_header_digest != 0) 588 keys_add(request_keys, "HeaderDigest", "CRC32C"); 589 else 590 keys_add(request_keys, "HeaderDigest", "None"); 591 if (conn->conn_conf.isc_data_digest != 0) 592 keys_add(request_keys, "DataDigest", "CRC32C"); 593 else 594 keys_add(request_keys, "DataDigest", "None"); 595 596 keys_add(request_keys, "ImmediateData", "Yes"); 597 keys_add_int(request_keys, "MaxBurstLength", 598 ISCSI_MAX_DATA_SEGMENT_LENGTH); 599 keys_add_int(request_keys, "FirstBurstLength", 600 ISCSI_MAX_DATA_SEGMENT_LENGTH); 601 keys_add(request_keys, "InitialR2T", "Yes"); 602 } else { 603 keys_add(request_keys, "HeaderDigest", "None"); 604 keys_add(request_keys, "DataDigest", "None"); 605 } 606 607 keys_add_int(request_keys, "MaxRecvDataSegmentLength", 608 ISCSI_MAX_DATA_SEGMENT_LENGTH); 609 keys_add(request_keys, "DefaultTime2Wait", "0"); 610 keys_add(request_keys, "DefaultTime2Retain", "0"); 611 keys_add(request_keys, "ErrorRecoveryLevel", "0"); 612 keys_add(request_keys, "MaxOutstandingR2T", "1"); 613 keys_save(request_keys, request); 614 keys_delete(request_keys); 615 request_keys = NULL; 616 pdu_send(request); 617 pdu_delete(request); 618 request = NULL; 619 620 response = login_receive(conn); 621 response_keys = keys_new(); 622 keys_load(response_keys, response); 623 for (i = 0; i < KEYS_MAX; i++) { 624 if (response_keys->keys_names[i] == NULL) 625 break; 626 627 login_negotiate_key(conn, 628 response_keys->keys_names[i], response_keys->keys_values[i]); 629 } 630 631 keys_delete(response_keys); 632 response_keys = NULL; 633 634 for (;;) { 635 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 636 if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0) 637 break; 638 639 nrequests++; 640 if (nrequests > 5) { 641 log_warnx("received login response " 642 "without the \"T\" flag too many times; giving up"); 643 break; 644 } 645 646 log_debugx("received login response " 647 "without the \"T\" flag; sending another request"); 648 649 pdu_delete(response); 650 651 request = login_new_request(conn, 652 BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 653 pdu_send(request); 654 pdu_delete(request); 655 656 response = login_receive(conn); 657 } 658 659 if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE) 660 log_warnx("received final login response with wrong NSG 0x%x", 661 login_nsg(response)); 662 pdu_delete(response); 663 664 log_debugx("operational parameter negotiation done; " 665 "transitioning to Full Feature phase"); 666} 667 668static void 669login_send_chap_a(struct connection *conn) 670{ 671 struct pdu *request; 672 struct keys *request_keys; 673 674 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 675 request_keys = keys_new(); 676 keys_add(request_keys, "CHAP_A", "5"); 677 keys_save(request_keys, request); 678 keys_delete(request_keys); 679 pdu_send(request); 680 pdu_delete(request); 681} 682 683static void 684login_send_chap_r(struct pdu *response) 685{ 686 struct connection *conn; 687 struct pdu *request; 688 struct keys *request_keys, *response_keys; 689 const char *chap_a, *chap_c, *chap_i; 690 char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH]; 691 size_t challenge_len; 692 int error, rv; 693 unsigned char id; 694 char *mutual_chap_c, mutual_chap_i[4]; 695 696 /* 697 * As in the rest of the initiator, 'request' means 698 * 'initiator -> target', and 'response' means 'target -> initiator', 699 * 700 * So, here the 'response' from the target is the packet that contains 701 * CHAP challenge; our CHAP response goes into 'request'. 702 */ 703 704 conn = response->pdu_connection; 705 706 response_keys = keys_new(); 707 keys_load(response_keys, response); 708 709 /* 710 * First, compute the response. 711 */ 712 chap_a = keys_find(response_keys, "CHAP_A"); 713 if (chap_a == NULL) 714 log_errx(1, "received CHAP packet without CHAP_A"); 715 chap_c = keys_find(response_keys, "CHAP_C"); 716 if (chap_c == NULL) 717 log_errx(1, "received CHAP packet without CHAP_C"); 718 chap_i = keys_find(response_keys, "CHAP_I"); 719 if (chap_i == NULL) 720 log_errx(1, "received CHAP packet without CHAP_I"); 721 722 if (strcmp(chap_a, "5") != 0) 723 log_errx(1, "received CHAP packet " 724 "with unsupported CHAP_A \"%s\"", chap_a); 725 id = strtoul(chap_i, NULL, 10); 726 error = login_hex2bin(chap_c, &challenge, &challenge_len); 727 if (error != 0) 728 log_errx(1, "received CHAP packet with malformed CHAP_C"); 729 login_compute_md5(id, conn->conn_conf.isc_secret, 730 challenge, challenge_len, response_bin, sizeof(response_bin)); 731 free(challenge); 732 chap_r = login_bin2hex(response_bin, sizeof(response_bin)); 733 734 keys_delete(response_keys); 735 736 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 737 request_keys = keys_new(); 738 keys_add(request_keys, "CHAP_N", conn->conn_conf.isc_user); 739 keys_add(request_keys, "CHAP_R", chap_r); 740 free(chap_r); 741 742 /* 743 * If we want mutual authentication, we're expected to send 744 * our CHAP_I/CHAP_C now. 745 */ 746 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 747 log_debugx("requesting mutual authentication; " 748 "binary challenge size is %zd bytes", 749 sizeof(conn->conn_mutual_challenge)); 750 751 rv = RAND_bytes(conn->conn_mutual_challenge, 752 sizeof(conn->conn_mutual_challenge)); 753 if (rv != 1) { 754 log_errx(1, "RAND_bytes failed: %s", 755 ERR_error_string(ERR_get_error(), NULL)); 756 } 757 rv = RAND_bytes(&conn->conn_mutual_id, 758 sizeof(conn->conn_mutual_id)); 759 if (rv != 1) { 760 log_errx(1, "RAND_bytes failed: %s", 761 ERR_error_string(ERR_get_error(), NULL)); 762 } 763 mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge, 764 sizeof(conn->conn_mutual_challenge)); 765 snprintf(mutual_chap_i, sizeof(mutual_chap_i), 766 "%d", conn->conn_mutual_id); 767 keys_add(request_keys, "CHAP_I", mutual_chap_i); 768 keys_add(request_keys, "CHAP_C", mutual_chap_c); 769 free(mutual_chap_c); 770 } 771 772 keys_save(request_keys, request); 773 keys_delete(request_keys); 774 pdu_send(request); 775 pdu_delete(request); 776} 777 778static void 779login_verify_mutual(const struct pdu *response) 780{ 781 struct connection *conn; 782 struct keys *response_keys; 783 const char *chap_n, *chap_r; 784 char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH]; 785 size_t response_bin_len; 786 int error; 787 788 conn = response->pdu_connection; 789 790 response_keys = keys_new(); 791 keys_load(response_keys, response); 792 793 chap_n = keys_find(response_keys, "CHAP_N"); 794 if (chap_n == NULL) 795 log_errx(1, "received CHAP Response PDU without CHAP_N"); 796 chap_r = keys_find(response_keys, "CHAP_R"); 797 if (chap_r == NULL) 798 log_errx(1, "received CHAP Response PDU without CHAP_R"); 799 error = login_hex2bin(chap_r, &response_bin, &response_bin_len); 800 if (error != 0) 801 log_errx(1, "received CHAP Response PDU with malformed CHAP_R"); 802 803 if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) { 804 fail(conn, "Mutual CHAP failed"); 805 log_errx(1, "mutual CHAP authentication failed: wrong user"); 806 } 807 808 login_compute_md5(conn->conn_mutual_id, 809 conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge, 810 sizeof(conn->conn_mutual_challenge), expected_response_bin, 811 sizeof(expected_response_bin)); 812 813 if (memcmp(response_bin, expected_response_bin, 814 sizeof(expected_response_bin)) != 0) { 815 fail(conn, "Mutual CHAP failed"); 816 log_errx(1, "mutual CHAP authentication failed: wrong secret"); 817 } 818 819 keys_delete(response_keys); 820 free(response_bin); 821 822 log_debugx("mutual CHAP authentication succeeded"); 823} 824 825static void 826login_chap(struct connection *conn) 827{ 828 struct pdu *response; 829 830 log_debugx("beginning CHAP authentication; sending CHAP_A"); 831 login_send_chap_a(conn); 832 833 log_debugx("waiting for CHAP_A/CHAP_C/CHAP_I"); 834 response = login_receive(conn); 835 836 log_debugx("sending CHAP_N/CHAP_R"); 837 login_send_chap_r(response); 838 pdu_delete(response); 839 840 /* 841 * XXX: Make sure this is not susceptible to MITM. 842 */ 843 844 log_debugx("waiting for CHAP result"); 845 response = login_receive(conn); 846 if (conn->conn_conf.isc_mutual_user[0] != '\0') 847 login_verify_mutual(response); 848 pdu_delete(response); 849 850 log_debugx("CHAP authentication done"); 851} 852 853void 854login(struct connection *conn) 855{ 856 struct pdu *request, *response; 857 struct keys *request_keys, *response_keys; 858 struct iscsi_bhs_login_response *bhslr2; 859 const char *auth_method; 860 int i; 861 862 log_debugx("beginning Login phase; sending Login PDU"); 863 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 864 request_keys = keys_new(); 865 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 866 keys_add(request_keys, "AuthMethod", "CHAP"); 867 } else if (conn->conn_conf.isc_user[0] != '\0') { 868 /* 869 * Give target a chance to skip authentication if it 870 * doesn't feel like it. 871 * 872 * None is first, CHAP second; this is to work around 873 * what seems to be LIO (Linux target) bug: otherwise, 874 * if target is configured with no authentication, 875 * and we are configured to authenticate, the target 876 * will erroneously respond with AuthMethod=CHAP 877 * instead of AuthMethod=None, and will subsequently 878 * fail the connection. This usually happens with 879 * Discovery sessions, which default to no authentication. 880 */ 881 keys_add(request_keys, "AuthMethod", "None,CHAP"); 882 } else { 883 keys_add(request_keys, "AuthMethod", "None"); 884 } 885 keys_add(request_keys, "InitiatorName", 886 conn->conn_conf.isc_initiator); 887 if (conn->conn_conf.isc_initiator_alias[0] != '\0') { 888 keys_add(request_keys, "InitiatorAlias", 889 conn->conn_conf.isc_initiator_alias); 890 } 891 if (conn->conn_conf.isc_discovery == 0) { 892 keys_add(request_keys, "SessionType", "Normal"); 893 keys_add(request_keys, 894 "TargetName", conn->conn_conf.isc_target); 895 } else { 896 keys_add(request_keys, "SessionType", "Discovery"); 897 } 898 keys_save(request_keys, request); 899 keys_delete(request_keys); 900 pdu_send(request); 901 pdu_delete(request); 902 903 response = login_receive(conn); 904 905 response_keys = keys_new(); 906 keys_load(response_keys, response); 907 908 for (i = 0; i < KEYS_MAX; i++) { 909 if (response_keys->keys_names[i] == NULL) 910 break; 911 912 /* 913 * Not interested in AuthMethod at this point; we only need 914 * to parse things such as TargetAlias. 915 * 916 * XXX: This is somewhat ugly. We should have a way to apply 917 * all the keys to the session and use that by default 918 * instead of discarding them. 919 */ 920 if (strcmp(response_keys->keys_names[i], "AuthMethod") == 0) 921 continue; 922 923 login_negotiate_key(conn, 924 response_keys->keys_names[i], response_keys->keys_values[i]); 925 } 926 927 bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs; 928 if ((bhslr2->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0 && 929 login_nsg(response) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) { 930 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 931 log_errx(1, "target requested transition " 932 "to operational parameter negotiation, " 933 "but we require mutual CHAP"); 934 } 935 936 log_debugx("target requested transition " 937 "to operational parameter negotiation"); 938 keys_delete(response_keys); 939 pdu_delete(response); 940 login_negotiate(conn); 941 return; 942 } 943 944 auth_method = keys_find(response_keys, "AuthMethod"); 945 if (auth_method == NULL) 946 log_errx(1, "received response without AuthMethod"); 947 if (strcmp(auth_method, "None") == 0) { 948 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 949 log_errx(1, "target does not require authantication, " 950 "but we require mutual CHAP"); 951 } 952 953 log_debugx("target does not require authentication"); 954 keys_delete(response_keys); 955 pdu_delete(response); 956 login_negotiate(conn); 957 return; 958 } 959 960 if (strcmp(auth_method, "CHAP") != 0) { 961 fail(conn, "Unsupported AuthMethod"); 962 log_errx(1, "received response " 963 "with unsupported AuthMethod \"%s\"", auth_method); 964 } 965 966 if (conn->conn_conf.isc_user[0] == '\0' || 967 conn->conn_conf.isc_secret[0] == '\0') { 968 fail(conn, "Authentication required"); 969 log_errx(1, "target requests CHAP authentication, but we don't " 970 "have user and secret"); 971 } 972 973 keys_delete(response_keys); 974 response_keys = NULL; 975 pdu_delete(response); 976 response = NULL; 977 978 login_chap(conn); 979 login_negotiate(conn); 980} 981