login.c revision 269068
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 269068 2014-07-24 15:41:16Z mav $ 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 47static int 48login_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 57static void 58login_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 72static void 73login_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 87static const char * 88login_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 162static void 163kernel_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 */ 190static void 191login_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 216static struct pdu * 217login_receive(struct connection *conn, bool initial) 218{ 219 struct pdu *response; 220 struct iscsi_bhs_login_response *bhslr; 221 const char *errorstr; 222 223 response = pdu_new(conn); 224 pdu_receive(response); 225 if (response->pdu_bhs->bhs_opcode != ISCSI_BHS_OPCODE_LOGIN_RESPONSE) { 226 log_errx(1, "protocol error: received invalid opcode 0x%x", 227 response->pdu_bhs->bhs_opcode); 228 } 229 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 230 /* 231 * XXX: Implement the C flag some day. 232 */ 233 if ((bhslr->bhslr_flags & BHSLR_FLAGS_CONTINUE) != 0) 234 log_errx(1, "received Login PDU with unsupported \"C\" flag"); 235 if (bhslr->bhslr_version_max != 0x00) 236 log_errx(1, "received Login PDU with unsupported " 237 "Version-max 0x%x", bhslr->bhslr_version_max); 238 if (bhslr->bhslr_version_active != 0x00) 239 log_errx(1, "received Login PDU with unsupported " 240 "Version-active 0x%x", bhslr->bhslr_version_active); 241 if (bhslr->bhslr_status_class == 1) { 242 login_handle_redirection(conn, response); 243 log_debugx("redirection handled; exiting"); 244 exit(0); 245 } 246 if (bhslr->bhslr_status_class != 0) { 247 errorstr = login_target_error_str(bhslr->bhslr_status_class, 248 bhslr->bhslr_status_detail); 249 fail(conn, errorstr); 250 log_errx(1, "target returned error: %s", errorstr); 251 } 252 if (initial == false && 253 ntohl(bhslr->bhslr_statsn) != conn->conn_statsn + 1) { 254 /* 255 * It's a warning, not an error, to work around what seems 256 * to be bug in NetBSD iSCSI target. 257 */ 258 log_warnx("received Login PDU with wrong StatSN: " 259 "is %d, should be %d", ntohl(bhslr->bhslr_statsn), 260 conn->conn_statsn + 1); 261 } 262 conn->conn_tsih = ntohs(bhslr->bhslr_tsih); 263 conn->conn_statsn = ntohl(bhslr->bhslr_statsn); 264 265 return (response); 266} 267 268static struct pdu * 269login_new_request(struct connection *conn, int csg) 270{ 271 struct pdu *request; 272 struct iscsi_bhs_login_request *bhslr; 273 int nsg; 274 275 request = pdu_new(conn); 276 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 277 bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_REQUEST | 278 ISCSI_BHS_OPCODE_IMMEDIATE; 279 280 bhslr->bhslr_flags = BHSLR_FLAGS_TRANSIT; 281 switch (csg) { 282 case BHSLR_STAGE_SECURITY_NEGOTIATION: 283 nsg = BHSLR_STAGE_OPERATIONAL_NEGOTIATION; 284 break; 285 case BHSLR_STAGE_OPERATIONAL_NEGOTIATION: 286 nsg = BHSLR_STAGE_FULL_FEATURE_PHASE; 287 break; 288 default: 289 assert(!"invalid csg"); 290 log_errx(1, "invalid csg %d", csg); 291 } 292 login_set_csg(request, csg); 293 login_set_nsg(request, nsg); 294 295 memcpy(bhslr->bhslr_isid, &conn->conn_isid, sizeof(bhslr->bhslr_isid)); 296 bhslr->bhslr_tsih = htons(conn->conn_tsih); 297 bhslr->bhslr_initiator_task_tag = 0; 298 bhslr->bhslr_cmdsn = 0; 299 bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1); 300 301 return (request); 302} 303 304static int 305login_list_prefers(const char *list, 306 const char *choice1, const char *choice2) 307{ 308 char *tofree, *str, *token; 309 310 tofree = str = checked_strdup(list); 311 312 while ((token = strsep(&str, ",")) != NULL) { 313 if (strcmp(token, choice1) == 0) { 314 free(tofree); 315 return (1); 316 } 317 if (strcmp(token, choice2) == 0) { 318 free(tofree); 319 return (2); 320 } 321 } 322 free(tofree); 323 return (-1); 324} 325 326static int 327login_hex2int(const char hex) 328{ 329 switch (hex) { 330 case '0': 331 return (0x00); 332 case '1': 333 return (0x01); 334 case '2': 335 return (0x02); 336 case '3': 337 return (0x03); 338 case '4': 339 return (0x04); 340 case '5': 341 return (0x05); 342 case '6': 343 return (0x06); 344 case '7': 345 return (0x07); 346 case '8': 347 return (0x08); 348 case '9': 349 return (0x09); 350 case 'a': 351 case 'A': 352 return (0x0a); 353 case 'b': 354 case 'B': 355 return (0x0b); 356 case 'c': 357 case 'C': 358 return (0x0c); 359 case 'd': 360 case 'D': 361 return (0x0d); 362 case 'e': 363 case 'E': 364 return (0x0e); 365 case 'f': 366 case 'F': 367 return (0x0f); 368 default: 369 return (-1); 370 } 371} 372 373/* 374 * XXX: Review this _carefully_. 375 */ 376static int 377login_hex2bin(const char *hex, char **binp, size_t *bin_lenp) 378{ 379 int i, hex_len, nibble; 380 bool lo = true; /* As opposed to 'hi'. */ 381 char *bin; 382 size_t bin_off, bin_len; 383 384 if (strncasecmp(hex, "0x", strlen("0x")) != 0) { 385 log_warnx("malformed variable, should start with \"0x\""); 386 return (-1); 387 } 388 389 hex += strlen("0x"); 390 hex_len = strlen(hex); 391 if (hex_len < 1) { 392 log_warnx("malformed variable; doesn't contain anything " 393 "but \"0x\""); 394 return (-1); 395 } 396 397 bin_len = hex_len / 2 + hex_len % 2; 398 bin = calloc(bin_len, 1); 399 if (bin == NULL) 400 log_err(1, "calloc"); 401 402 bin_off = bin_len - 1; 403 for (i = hex_len - 1; i >= 0; i--) { 404 nibble = login_hex2int(hex[i]); 405 if (nibble < 0) { 406 log_warnx("malformed variable, invalid char \"%c\"", 407 hex[i]); 408 return (-1); 409 } 410 411 assert(bin_off < bin_len); 412 if (lo) { 413 bin[bin_off] = nibble; 414 lo = false; 415 } else { 416 bin[bin_off] |= nibble << 4; 417 bin_off--; 418 lo = true; 419 } 420 } 421 422 *binp = bin; 423 *bin_lenp = bin_len; 424 return (0); 425} 426 427static char * 428login_bin2hex(const char *bin, size_t bin_len) 429{ 430 unsigned char *hex, *tmp, ch; 431 size_t hex_len; 432 size_t i; 433 434 hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */ 435 hex = malloc(hex_len); 436 if (hex == NULL) 437 log_err(1, "malloc"); 438 439 tmp = hex; 440 tmp += sprintf(tmp, "0x"); 441 for (i = 0; i < bin_len; i++) { 442 ch = bin[i]; 443 tmp += sprintf(tmp, "%02x", ch); 444 } 445 446 return (hex); 447} 448 449static void 450login_compute_md5(const char id, const char *secret, 451 const void *challenge, size_t challenge_len, void *response, 452 size_t response_len) 453{ 454 MD5_CTX ctx; 455 int rv; 456 457 assert(response_len == MD5_DIGEST_LENGTH); 458 459 MD5_Init(&ctx); 460 MD5_Update(&ctx, &id, sizeof(id)); 461 MD5_Update(&ctx, secret, strlen(secret)); 462 MD5_Update(&ctx, challenge, challenge_len); 463 rv = MD5_Final(response, &ctx); 464 if (rv != 1) 465 log_errx(1, "MD5_Final"); 466} 467 468static void 469login_negotiate_key(struct connection *conn, const char *name, 470 const char *value) 471{ 472 int which, tmp; 473 474 if (strcmp(name, "TargetAlias") == 0) { 475 strlcpy(conn->conn_target_alias, value, 476 sizeof(conn->conn_target_alias)); 477 } else if (strcmp(value, "Irrelevant") == 0) { 478 /* Ignore. */ 479 } else if (strcmp(name, "HeaderDigest") == 0) { 480 which = login_list_prefers(value, "CRC32C", "None"); 481 switch (which) { 482 case 1: 483 log_debugx("target prefers CRC32C " 484 "for header digest; we'll use it"); 485 conn->conn_header_digest = CONN_DIGEST_CRC32C; 486 break; 487 case 2: 488 log_debugx("target prefers not to do " 489 "header digest; we'll comply"); 490 break; 491 default: 492 log_warnx("target sent unrecognized " 493 "HeaderDigest value \"%s\"; will use None", value); 494 break; 495 } 496 } else if (strcmp(name, "DataDigest") == 0) { 497 which = login_list_prefers(value, "CRC32C", "None"); 498 switch (which) { 499 case 1: 500 log_debugx("target prefers CRC32C " 501 "for data digest; we'll use it"); 502 conn->conn_data_digest = CONN_DIGEST_CRC32C; 503 break; 504 case 2: 505 log_debugx("target prefers not to do " 506 "data digest; we'll comply"); 507 break; 508 default: 509 log_warnx("target sent unrecognized " 510 "DataDigest value \"%s\"; will use None", value); 511 break; 512 } 513 } else if (strcmp(name, "MaxConnections") == 0) { 514 /* Ignore. */ 515 } else if (strcmp(name, "InitialR2T") == 0) { 516 if (strcmp(value, "Yes") == 0) 517 conn->conn_initial_r2t = true; 518 else 519 conn->conn_initial_r2t = false; 520 } else if (strcmp(name, "ImmediateData") == 0) { 521 if (strcmp(value, "Yes") == 0) 522 conn->conn_immediate_data = true; 523 else 524 conn->conn_immediate_data = false; 525 } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) { 526 tmp = strtoul(value, NULL, 10); 527 if (tmp <= 0) 528 log_errx(1, "received invalid " 529 "MaxRecvDataSegmentLength"); 530 conn->conn_max_data_segment_length = tmp; 531 } else if (strcmp(name, "MaxBurstLength") == 0) { 532 if (conn->conn_immediate_data) { 533 tmp = strtoul(value, NULL, 10); 534 if (tmp <= 0) 535 log_errx(1, "received invalid MaxBurstLength"); 536 conn->conn_max_burst_length = tmp; 537 } 538 } else if (strcmp(name, "FirstBurstLength") == 0) { 539 tmp = strtoul(value, NULL, 10); 540 if (tmp <= 0) 541 log_errx(1, "received invalid FirstBurstLength"); 542 conn->conn_first_burst_length = tmp; 543 } else if (strcmp(name, "DefaultTime2Wait") == 0) { 544 /* Ignore */ 545 } else if (strcmp(name, "DefaultTime2Retain") == 0) { 546 /* Ignore */ 547 } else if (strcmp(name, "MaxOutstandingR2T") == 0) { 548 /* Ignore */ 549 } else if (strcmp(name, "DataPDUInOrder") == 0) { 550 /* Ignore */ 551 } else if (strcmp(name, "DataSequenceInOrder") == 0) { 552 /* Ignore */ 553 } else if (strcmp(name, "ErrorRecoveryLevel") == 0) { 554 /* Ignore */ 555 } else if (strcmp(name, "OFMarker") == 0) { 556 /* Ignore */ 557 } else if (strcmp(name, "IFMarker") == 0) { 558 /* Ignore */ 559 } else if (strcmp(name, "TargetPortalGroupTag") == 0) { 560 /* Ignore */ 561 } else { 562 log_debugx("unknown key \"%s\"; ignoring", name); 563 } 564} 565 566static void 567login_negotiate(struct connection *conn) 568{ 569 struct pdu *request, *response; 570 struct keys *request_keys, *response_keys; 571 struct iscsi_bhs_login_response *bhslr; 572 int i; 573 574 log_debugx("beginning operational parameter negotiation"); 575 request = login_new_request(conn, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 576 request_keys = keys_new(); 577 578 /* 579 * The following keys are irrelevant for discovery sessions. 580 */ 581 if (conn->conn_conf.isc_discovery == 0) { 582 if (conn->conn_conf.isc_header_digest != 0) 583 keys_add(request_keys, "HeaderDigest", "CRC32C"); 584 else 585 keys_add(request_keys, "HeaderDigest", "None"); 586 if (conn->conn_conf.isc_data_digest != 0) 587 keys_add(request_keys, "DataDigest", "CRC32C"); 588 else 589 keys_add(request_keys, "DataDigest", "None"); 590 591 keys_add(request_keys, "ImmediateData", "Yes"); 592 keys_add_int(request_keys, "MaxBurstLength", 593 ISCSI_MAX_DATA_SEGMENT_LENGTH); 594 keys_add_int(request_keys, "FirstBurstLength", 595 ISCSI_MAX_DATA_SEGMENT_LENGTH); 596 keys_add(request_keys, "InitialR2T", "Yes"); 597 } else { 598 keys_add(request_keys, "HeaderDigest", "None"); 599 keys_add(request_keys, "DataDigest", "None"); 600 } 601 602 keys_add_int(request_keys, "MaxRecvDataSegmentLength", 603 ISCSI_MAX_DATA_SEGMENT_LENGTH); 604 keys_add(request_keys, "DefaultTime2Wait", "0"); 605 keys_add(request_keys, "DefaultTime2Retain", "0"); 606 keys_add(request_keys, "ErrorRecoveryLevel", "0"); 607 keys_add(request_keys, "MaxOutstandingR2T", "1"); 608 keys_save(request_keys, request); 609 keys_delete(request_keys); 610 request_keys = NULL; 611 pdu_send(request); 612 pdu_delete(request); 613 request = NULL; 614 615 response = login_receive(conn, false); 616 response_keys = keys_new(); 617 keys_load(response_keys, response); 618 for (i = 0; i < KEYS_MAX; i++) { 619 if (response_keys->keys_names[i] == NULL) 620 break; 621 622 login_negotiate_key(conn, 623 response_keys->keys_names[i], response_keys->keys_values[i]); 624 } 625 626 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 627 if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0) 628 log_warnx("received final login response " 629 "without the \"T\" flag"); 630 else if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE) 631 log_warnx("received final login response with wrong NSG 0x%x", 632 login_nsg(response)); 633 634 log_debugx("operational parameter negotiation done; " 635 "transitioning to Full Feature phase"); 636 637 keys_delete(response_keys); 638 pdu_delete(response); 639} 640 641static void 642login_send_chap_a(struct connection *conn) 643{ 644 struct pdu *request; 645 struct keys *request_keys; 646 647 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 648 request_keys = keys_new(); 649 keys_add(request_keys, "CHAP_A", "5"); 650 keys_save(request_keys, request); 651 keys_delete(request_keys); 652 pdu_send(request); 653 pdu_delete(request); 654} 655 656static void 657login_send_chap_r(struct pdu *response) 658{ 659 struct connection *conn; 660 struct pdu *request; 661 struct keys *request_keys, *response_keys; 662 const char *chap_a, *chap_c, *chap_i; 663 char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH]; 664 size_t challenge_len; 665 int error, rv; 666 unsigned char id; 667 char *mutual_chap_c, mutual_chap_i[4]; 668 669 /* 670 * As in the rest of the initiator, 'request' means 671 * 'initiator -> target', and 'response' means 'target -> initiator', 672 * 673 * So, here the 'response' from the target is the packet that contains 674 * CHAP challenge; our CHAP response goes into 'request'. 675 */ 676 677 conn = response->pdu_connection; 678 679 response_keys = keys_new(); 680 keys_load(response_keys, response); 681 682 /* 683 * First, compute the response. 684 */ 685 chap_a = keys_find(response_keys, "CHAP_A"); 686 if (chap_a == NULL) 687 log_errx(1, "received CHAP packet without CHAP_A"); 688 chap_c = keys_find(response_keys, "CHAP_C"); 689 if (chap_c == NULL) 690 log_errx(1, "received CHAP packet without CHAP_C"); 691 chap_i = keys_find(response_keys, "CHAP_I"); 692 if (chap_i == NULL) 693 log_errx(1, "received CHAP packet without CHAP_I"); 694 695 if (strcmp(chap_a, "5") != 0) 696 log_errx(1, "received CHAP packet " 697 "with unsupported CHAP_A \"%s\"", chap_a); 698 id = strtoul(chap_i, NULL, 10); 699 error = login_hex2bin(chap_c, &challenge, &challenge_len); 700 if (error != 0) 701 log_errx(1, "received CHAP packet with malformed CHAP_C"); 702 login_compute_md5(id, conn->conn_conf.isc_secret, 703 challenge, challenge_len, response_bin, sizeof(response_bin)); 704 free(challenge); 705 chap_r = login_bin2hex(response_bin, sizeof(response_bin)); 706 707 keys_delete(response_keys); 708 709 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 710 request_keys = keys_new(); 711 keys_add(request_keys, "CHAP_N", conn->conn_conf.isc_user); 712 keys_add(request_keys, "CHAP_R", chap_r); 713 free(chap_r); 714 715 /* 716 * If we want mutual authentication, we're expected to send 717 * our CHAP_I/CHAP_C now. 718 */ 719 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 720 log_debugx("requesting mutual authentication; " 721 "binary challenge size is %zd bytes", 722 sizeof(conn->conn_mutual_challenge)); 723 724 rv = RAND_bytes(conn->conn_mutual_challenge, 725 sizeof(conn->conn_mutual_challenge)); 726 if (rv != 1) { 727 log_errx(1, "RAND_bytes failed: %s", 728 ERR_error_string(ERR_get_error(), NULL)); 729 } 730 rv = RAND_bytes(&conn->conn_mutual_id, 731 sizeof(conn->conn_mutual_id)); 732 if (rv != 1) { 733 log_errx(1, "RAND_bytes failed: %s", 734 ERR_error_string(ERR_get_error(), NULL)); 735 } 736 mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge, 737 sizeof(conn->conn_mutual_challenge)); 738 snprintf(mutual_chap_i, sizeof(mutual_chap_i), 739 "%d", conn->conn_mutual_id); 740 keys_add(request_keys, "CHAP_I", mutual_chap_i); 741 keys_add(request_keys, "CHAP_C", mutual_chap_c); 742 free(mutual_chap_c); 743 } 744 745 keys_save(request_keys, request); 746 keys_delete(request_keys); 747 pdu_send(request); 748 pdu_delete(request); 749} 750 751static void 752login_verify_mutual(const struct pdu *response) 753{ 754 struct connection *conn; 755 struct keys *response_keys; 756 const char *chap_n, *chap_r; 757 char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH]; 758 size_t response_bin_len; 759 int error; 760 761 conn = response->pdu_connection; 762 763 response_keys = keys_new(); 764 keys_load(response_keys, response); 765 766 chap_n = keys_find(response_keys, "CHAP_N"); 767 if (chap_n == NULL) 768 log_errx(1, "received CHAP Response PDU without CHAP_N"); 769 chap_r = keys_find(response_keys, "CHAP_R"); 770 if (chap_r == NULL) 771 log_errx(1, "received CHAP Response PDU without CHAP_R"); 772 error = login_hex2bin(chap_r, &response_bin, &response_bin_len); 773 if (error != 0) 774 log_errx(1, "received CHAP Response PDU with malformed CHAP_R"); 775 776 if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) { 777 fail(conn, "Mutual CHAP failed"); 778 log_errx(1, "mutual CHAP authentication failed: wrong user"); 779 } 780 781 login_compute_md5(conn->conn_mutual_id, 782 conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge, 783 sizeof(conn->conn_mutual_challenge), expected_response_bin, 784 sizeof(expected_response_bin)); 785 786 if (memcmp(response_bin, expected_response_bin, 787 sizeof(expected_response_bin)) != 0) { 788 fail(conn, "Mutual CHAP failed"); 789 log_errx(1, "mutual CHAP authentication failed: wrong secret"); 790 } 791 792 keys_delete(response_keys); 793 free(response_bin); 794 795 log_debugx("mutual CHAP authentication succeeded"); 796} 797 798static void 799login_chap(struct connection *conn) 800{ 801 struct pdu *response; 802 803 log_debugx("beginning CHAP authentication; sending CHAP_A"); 804 login_send_chap_a(conn); 805 806 log_debugx("waiting for CHAP_A/CHAP_C/CHAP_I"); 807 response = login_receive(conn, false); 808 809 log_debugx("sending CHAP_N/CHAP_R"); 810 login_send_chap_r(response); 811 pdu_delete(response); 812 813 /* 814 * XXX: Make sure this is not susceptible to MITM. 815 */ 816 817 log_debugx("waiting for CHAP result"); 818 response = login_receive(conn, false); 819 if (conn->conn_conf.isc_mutual_user[0] != '\0') 820 login_verify_mutual(response); 821 pdu_delete(response); 822 823 log_debugx("CHAP authentication done"); 824} 825 826void 827login(struct connection *conn) 828{ 829 struct pdu *request, *response; 830 struct keys *request_keys, *response_keys; 831 struct iscsi_bhs_login_response *bhslr2; 832 const char *auth_method; 833 int i; 834 835 log_debugx("beginning Login phase; sending Login PDU"); 836 request = login_new_request(conn, BHSLR_STAGE_SECURITY_NEGOTIATION); 837 request_keys = keys_new(); 838 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 839 keys_add(request_keys, "AuthMethod", "CHAP"); 840 } else if (conn->conn_conf.isc_user[0] != '\0') { 841 /* 842 * Give target a chance to skip authentication if it 843 * doesn't feel like it. 844 * 845 * None is first, CHAP second; this is to work around 846 * what seems to be LIO (Linux target) bug: otherwise, 847 * if target is configured with no authentication, 848 * and we are configured to authenticate, the target 849 * will erroneously respond with AuthMethod=CHAP 850 * instead of AuthMethod=None, and will subsequently 851 * fail the connection. This usually happens with 852 * Discovery sessions, which default to no authentication. 853 */ 854 keys_add(request_keys, "AuthMethod", "None,CHAP"); 855 } else { 856 keys_add(request_keys, "AuthMethod", "None"); 857 } 858 keys_add(request_keys, "InitiatorName", 859 conn->conn_conf.isc_initiator); 860 if (conn->conn_conf.isc_initiator_alias[0] != '\0') { 861 keys_add(request_keys, "InitiatorAlias", 862 conn->conn_conf.isc_initiator_alias); 863 } 864 if (conn->conn_conf.isc_discovery == 0) { 865 keys_add(request_keys, "SessionType", "Normal"); 866 keys_add(request_keys, 867 "TargetName", conn->conn_conf.isc_target); 868 } else { 869 keys_add(request_keys, "SessionType", "Discovery"); 870 } 871 keys_save(request_keys, request); 872 keys_delete(request_keys); 873 pdu_send(request); 874 pdu_delete(request); 875 876 response = login_receive(conn, true); 877 878 response_keys = keys_new(); 879 keys_load(response_keys, response); 880 881 for (i = 0; i < KEYS_MAX; i++) { 882 if (response_keys->keys_names[i] == NULL) 883 break; 884 885 /* 886 * Not interested in AuthMethod at this point; we only need 887 * to parse things such as TargetAlias. 888 * 889 * XXX: This is somewhat ugly. We should have a way to apply 890 * all the keys to the session and use that by default 891 * instead of discarding them. 892 */ 893 if (strcmp(response_keys->keys_names[i], "AuthMethod") == 0) 894 continue; 895 896 login_negotiate_key(conn, 897 response_keys->keys_names[i], response_keys->keys_values[i]); 898 } 899 900 bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs; 901 if ((bhslr2->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0 && 902 login_nsg(response) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) { 903 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 904 log_errx(1, "target requested transition " 905 "to operational parameter negotiation, " 906 "but we require mutual CHAP"); 907 } 908 909 log_debugx("target requested transition " 910 "to operational parameter negotiation"); 911 keys_delete(response_keys); 912 pdu_delete(response); 913 login_negotiate(conn); 914 return; 915 } 916 917 auth_method = keys_find(response_keys, "AuthMethod"); 918 if (auth_method == NULL) 919 log_errx(1, "received response without AuthMethod"); 920 if (strcmp(auth_method, "None") == 0) { 921 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 922 log_errx(1, "target does not require authantication, " 923 "but we require mutual CHAP"); 924 } 925 926 log_debugx("target does not require authentication"); 927 keys_delete(response_keys); 928 pdu_delete(response); 929 login_negotiate(conn); 930 return; 931 } 932 933 if (strcmp(auth_method, "CHAP") != 0) { 934 fail(conn, "Unsupported AuthMethod"); 935 log_errx(1, "received response " 936 "with unsupported AuthMethod \"%s\"", auth_method); 937 } 938 939 if (conn->conn_conf.isc_user[0] == '\0' || 940 conn->conn_conf.isc_secret[0] == '\0') { 941 fail(conn, "Authentication required"); 942 log_errx(1, "target requests CHAP authentication, but we don't " 943 "have user and secret"); 944 } 945 946 keys_delete(response_keys); 947 response_keys = NULL; 948 pdu_delete(response); 949 response = NULL; 950 951 login_chap(conn); 952 login_negotiate(conn); 953} 954