login.c revision 268703
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 268703 2014-07-15 18:21:26Z mav $ 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_tsih = ntohs(bhslr->bhslr_tsih); 203 conn->conn_statsn = ntohl(bhslr->bhslr_statsn); 204 205 return (response); 206} 207 208static struct pdu * 209login_new_request(struct connection *conn) 210{ 211 struct pdu *request; 212 struct iscsi_bhs_login_request *bhslr; 213 214 request = pdu_new(conn); 215 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 216 bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_REQUEST | 217 ISCSI_BHS_OPCODE_IMMEDIATE; 218 bhslr->bhslr_flags = BHSLR_FLAGS_TRANSIT; 219 login_set_csg(request, BHSLR_STAGE_SECURITY_NEGOTIATION); 220 login_set_nsg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 221 memcpy(bhslr->bhslr_isid, &conn->conn_isid, sizeof(bhslr->bhslr_isid)); 222 bhslr->bhslr_tsih = htons(conn->conn_tsih); 223 bhslr->bhslr_initiator_task_tag = 0; 224 bhslr->bhslr_cmdsn = 0; 225 bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1); 226 227 return (request); 228} 229 230static int 231login_list_prefers(const char *list, 232 const char *choice1, const char *choice2) 233{ 234 char *tofree, *str, *token; 235 236 tofree = str = checked_strdup(list); 237 238 while ((token = strsep(&str, ",")) != NULL) { 239 if (strcmp(token, choice1) == 0) { 240 free(tofree); 241 return (1); 242 } 243 if (strcmp(token, choice2) == 0) { 244 free(tofree); 245 return (2); 246 } 247 } 248 free(tofree); 249 return (-1); 250} 251 252static int 253login_hex2int(const char hex) 254{ 255 switch (hex) { 256 case '0': 257 return (0x00); 258 case '1': 259 return (0x01); 260 case '2': 261 return (0x02); 262 case '3': 263 return (0x03); 264 case '4': 265 return (0x04); 266 case '5': 267 return (0x05); 268 case '6': 269 return (0x06); 270 case '7': 271 return (0x07); 272 case '8': 273 return (0x08); 274 case '9': 275 return (0x09); 276 case 'a': 277 case 'A': 278 return (0x0a); 279 case 'b': 280 case 'B': 281 return (0x0b); 282 case 'c': 283 case 'C': 284 return (0x0c); 285 case 'd': 286 case 'D': 287 return (0x0d); 288 case 'e': 289 case 'E': 290 return (0x0e); 291 case 'f': 292 case 'F': 293 return (0x0f); 294 default: 295 return (-1); 296 } 297} 298 299/* 300 * XXX: Review this _carefully_. 301 */ 302static int 303login_hex2bin(const char *hex, char **binp, size_t *bin_lenp) 304{ 305 int i, hex_len, nibble; 306 bool lo = true; /* As opposed to 'hi'. */ 307 char *bin; 308 size_t bin_off, bin_len; 309 310 if (strncasecmp(hex, "0x", strlen("0x")) != 0) { 311 log_warnx("malformed variable, should start with \"0x\""); 312 return (-1); 313 } 314 315 hex += strlen("0x"); 316 hex_len = strlen(hex); 317 if (hex_len < 1) { 318 log_warnx("malformed variable; doesn't contain anything " 319 "but \"0x\""); 320 return (-1); 321 } 322 323 bin_len = hex_len / 2 + hex_len % 2; 324 bin = calloc(bin_len, 1); 325 if (bin == NULL) 326 log_err(1, "calloc"); 327 328 bin_off = bin_len - 1; 329 for (i = hex_len - 1; i >= 0; i--) { 330 nibble = login_hex2int(hex[i]); 331 if (nibble < 0) { 332 log_warnx("malformed variable, invalid char \"%c\"", 333 hex[i]); 334 return (-1); 335 } 336 337 assert(bin_off < bin_len); 338 if (lo) { 339 bin[bin_off] = nibble; 340 lo = false; 341 } else { 342 bin[bin_off] |= nibble << 4; 343 bin_off--; 344 lo = true; 345 } 346 } 347 348 *binp = bin; 349 *bin_lenp = bin_len; 350 return (0); 351} 352 353static char * 354login_bin2hex(const char *bin, size_t bin_len) 355{ 356 unsigned char *hex, *tmp, ch; 357 size_t hex_len; 358 size_t i; 359 360 hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */ 361 hex = malloc(hex_len); 362 if (hex == NULL) 363 log_err(1, "malloc"); 364 365 tmp = hex; 366 tmp += sprintf(tmp, "0x"); 367 for (i = 0; i < bin_len; i++) { 368 ch = bin[i]; 369 tmp += sprintf(tmp, "%02x", ch); 370 } 371 372 return (hex); 373} 374 375static void 376login_compute_md5(const char id, const char *secret, 377 const void *challenge, size_t challenge_len, void *response, 378 size_t response_len) 379{ 380 MD5_CTX ctx; 381 int rv; 382 383 assert(response_len == MD5_DIGEST_LENGTH); 384 385 MD5_Init(&ctx); 386 MD5_Update(&ctx, &id, sizeof(id)); 387 MD5_Update(&ctx, secret, strlen(secret)); 388 MD5_Update(&ctx, challenge, challenge_len); 389 rv = MD5_Final(response, &ctx); 390 if (rv != 1) 391 log_errx(1, "MD5_Final"); 392} 393 394static void 395login_negotiate_key(struct connection *conn, const char *name, 396 const char *value) 397{ 398 int which, tmp; 399 400 if (strcmp(name, "TargetAlias") == 0) { 401 strlcpy(conn->conn_target_alias, value, 402 sizeof(conn->conn_target_alias)); 403 } else if (strcmp(value, "Irrelevant") == 0) { 404 /* Ignore. */ 405 } else if (strcmp(name, "HeaderDigest") == 0) { 406 which = login_list_prefers(value, "CRC32C", "None"); 407 switch (which) { 408 case 1: 409 log_debugx("target prefers CRC32C " 410 "for header digest; we'll use it"); 411 conn->conn_header_digest = CONN_DIGEST_CRC32C; 412 break; 413 case 2: 414 log_debugx("target prefers not to do " 415 "header digest; we'll comply"); 416 break; 417 default: 418 log_warnx("target sent unrecognized " 419 "HeaderDigest value \"%s\"; will use None", value); 420 break; 421 } 422 } else if (strcmp(name, "DataDigest") == 0) { 423 which = login_list_prefers(value, "CRC32C", "None"); 424 switch (which) { 425 case 1: 426 log_debugx("target prefers CRC32C " 427 "for data digest; we'll use it"); 428 conn->conn_data_digest = CONN_DIGEST_CRC32C; 429 break; 430 case 2: 431 log_debugx("target prefers not to do " 432 "data digest; we'll comply"); 433 break; 434 default: 435 log_warnx("target sent unrecognized " 436 "DataDigest value \"%s\"; will use None", value); 437 break; 438 } 439 } else if (strcmp(name, "MaxConnections") == 0) { 440 /* Ignore. */ 441 } else if (strcmp(name, "InitialR2T") == 0) { 442 if (strcmp(value, "Yes") == 0) 443 conn->conn_initial_r2t = true; 444 else 445 conn->conn_initial_r2t = false; 446 } else if (strcmp(name, "ImmediateData") == 0) { 447 if (strcmp(value, "Yes") == 0) 448 conn->conn_immediate_data = true; 449 else 450 conn->conn_immediate_data = false; 451 } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) { 452 tmp = strtoul(value, NULL, 10); 453 if (tmp <= 0) 454 log_errx(1, "received invalid " 455 "MaxRecvDataSegmentLength"); 456 conn->conn_max_data_segment_length = tmp; 457 } else if (strcmp(name, "MaxBurstLength") == 0) { 458 if (conn->conn_immediate_data) { 459 tmp = strtoul(value, NULL, 10); 460 if (tmp <= 0) 461 log_errx(1, "received invalid MaxBurstLength"); 462 conn->conn_max_burst_length = tmp; 463 } 464 } else if (strcmp(name, "FirstBurstLength") == 0) { 465 tmp = strtoul(value, NULL, 10); 466 if (tmp <= 0) 467 log_errx(1, "received invalid FirstBurstLength"); 468 conn->conn_first_burst_length = tmp; 469 } else if (strcmp(name, "DefaultTime2Wait") == 0) { 470 /* Ignore */ 471 } else if (strcmp(name, "DefaultTime2Retain") == 0) { 472 /* Ignore */ 473 } else if (strcmp(name, "MaxOutstandingR2T") == 0) { 474 /* Ignore */ 475 } else if (strcmp(name, "DataPDUInOrder") == 0) { 476 /* Ignore */ 477 } else if (strcmp(name, "DataSequenceInOrder") == 0) { 478 /* Ignore */ 479 } else if (strcmp(name, "ErrorRecoveryLevel") == 0) { 480 /* Ignore */ 481 } else if (strcmp(name, "OFMarker") == 0) { 482 /* Ignore */ 483 } else if (strcmp(name, "IFMarker") == 0) { 484 /* Ignore */ 485 } else if (strcmp(name, "TargetPortalGroupTag") == 0) { 486 /* Ignore */ 487 } else { 488 log_debugx("unknown key \"%s\"; ignoring", name); 489 } 490} 491 492static void 493login_negotiate(struct connection *conn) 494{ 495 struct pdu *request, *response; 496 struct keys *request_keys, *response_keys; 497 struct iscsi_bhs_login_response *bhslr; 498 int i; 499 500 log_debugx("beginning parameter negotiation"); 501 request = login_new_request(conn); 502 login_set_csg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 503 login_set_nsg(request, BHSLR_STAGE_FULL_FEATURE_PHASE); 504 request_keys = keys_new(); 505 506 /* 507 * The following keys are irrelevant for discovery sessions. 508 */ 509 if (conn->conn_conf.isc_discovery == 0) { 510 if (conn->conn_conf.isc_header_digest != 0) 511 keys_add(request_keys, "HeaderDigest", "CRC32C"); 512 else 513 keys_add(request_keys, "HeaderDigest", "None"); 514 if (conn->conn_conf.isc_data_digest != 0) 515 keys_add(request_keys, "DataDigest", "CRC32C"); 516 else 517 keys_add(request_keys, "DataDigest", "None"); 518 519 keys_add(request_keys, "ImmediateData", "Yes"); 520 keys_add_int(request_keys, "MaxBurstLength", 521 ISCSI_MAX_DATA_SEGMENT_LENGTH); 522 keys_add_int(request_keys, "FirstBurstLength", 523 ISCSI_MAX_DATA_SEGMENT_LENGTH); 524 keys_add(request_keys, "InitialR2T", "Yes"); 525 } else { 526 keys_add(request_keys, "HeaderDigest", "None"); 527 keys_add(request_keys, "DataDigest", "None"); 528 } 529 530 keys_add_int(request_keys, "MaxRecvDataSegmentLength", 531 ISCSI_MAX_DATA_SEGMENT_LENGTH); 532 keys_add(request_keys, "DefaultTime2Wait", "0"); 533 keys_add(request_keys, "DefaultTime2Retain", "0"); 534 keys_add(request_keys, "ErrorRecoveryLevel", "0"); 535 keys_add(request_keys, "MaxOutstandingR2T", "1"); 536 keys_save(request_keys, request); 537 keys_delete(request_keys); 538 request_keys = NULL; 539 pdu_send(request); 540 pdu_delete(request); 541 request = NULL; 542 543 response = login_receive(conn, false); 544 response_keys = keys_new(); 545 keys_load(response_keys, response); 546 for (i = 0; i < KEYS_MAX; i++) { 547 if (response_keys->keys_names[i] == NULL) 548 break; 549 550 login_negotiate_key(conn, 551 response_keys->keys_names[i], response_keys->keys_values[i]); 552 } 553 554 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 555 if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0) 556 log_warnx("received final login response " 557 "without the \"T\" flag"); 558 else if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE) 559 log_warnx("received final login response with wrong NSG 0x%x", 560 login_nsg(response)); 561 562 log_debugx("parameter negotiation done; " 563 "transitioning to Full Feature phase"); 564 565 keys_delete(response_keys); 566 pdu_delete(response); 567} 568 569static void 570login_send_chap_a(struct connection *conn) 571{ 572 struct pdu *request; 573 struct keys *request_keys; 574 575 request = login_new_request(conn); 576 request_keys = keys_new(); 577 keys_add(request_keys, "CHAP_A", "5"); 578 keys_save(request_keys, request); 579 keys_delete(request_keys); 580 pdu_send(request); 581 pdu_delete(request); 582} 583 584static void 585login_send_chap_r(struct pdu *response) 586{ 587 struct connection *conn; 588 struct pdu *request; 589 struct keys *request_keys, *response_keys; 590 const char *chap_a, *chap_c, *chap_i; 591 char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH]; 592 size_t challenge_len; 593 int error, rv; 594 unsigned char id; 595 char *mutual_chap_c, mutual_chap_i[4]; 596 597 /* 598 * As in the rest of the initiator, 'request' means 599 * 'initiator -> target', and 'response' means 'target -> initiator', 600 * 601 * So, here the 'response' from the target is the packet that contains 602 * CHAP challenge; our CHAP response goes into 'request'. 603 */ 604 605 conn = response->pdu_connection; 606 607 response_keys = keys_new(); 608 keys_load(response_keys, response); 609 610 /* 611 * First, compute the response. 612 */ 613 chap_a = keys_find(response_keys, "CHAP_A"); 614 if (chap_a == NULL) 615 log_errx(1, "received CHAP packet without CHAP_A"); 616 chap_c = keys_find(response_keys, "CHAP_C"); 617 if (chap_c == NULL) 618 log_errx(1, "received CHAP packet without CHAP_C"); 619 chap_i = keys_find(response_keys, "CHAP_I"); 620 if (chap_i == NULL) 621 log_errx(1, "received CHAP packet without CHAP_I"); 622 623 if (strcmp(chap_a, "5") != 0) 624 log_errx(1, "received CHAP packet " 625 "with unsupported CHAP_A \"%s\"", chap_a); 626 id = strtoul(chap_i, NULL, 10); 627 error = login_hex2bin(chap_c, &challenge, &challenge_len); 628 if (error != 0) 629 log_errx(1, "received CHAP packet with malformed CHAP_C"); 630 login_compute_md5(id, conn->conn_conf.isc_secret, 631 challenge, challenge_len, response_bin, sizeof(response_bin)); 632 free(challenge); 633 chap_r = login_bin2hex(response_bin, sizeof(response_bin)); 634 635 keys_delete(response_keys); 636 637 request = login_new_request(conn); 638 request_keys = keys_new(); 639 keys_add(request_keys, "CHAP_N", conn->conn_conf.isc_user); 640 keys_add(request_keys, "CHAP_R", chap_r); 641 free(chap_r); 642 643 /* 644 * If we want mutual authentication, we're expected to send 645 * our CHAP_I/CHAP_C now. 646 */ 647 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 648 log_debugx("requesting mutual authentication; " 649 "binary challenge size is %zd bytes", 650 sizeof(conn->conn_mutual_challenge)); 651 652 rv = RAND_bytes(conn->conn_mutual_challenge, 653 sizeof(conn->conn_mutual_challenge)); 654 if (rv != 1) { 655 log_errx(1, "RAND_bytes failed: %s", 656 ERR_error_string(ERR_get_error(), NULL)); 657 } 658 rv = RAND_bytes(&conn->conn_mutual_id, 659 sizeof(conn->conn_mutual_id)); 660 if (rv != 1) { 661 log_errx(1, "RAND_bytes failed: %s", 662 ERR_error_string(ERR_get_error(), NULL)); 663 } 664 mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge, 665 sizeof(conn->conn_mutual_challenge)); 666 snprintf(mutual_chap_i, sizeof(mutual_chap_i), 667 "%d", conn->conn_mutual_id); 668 keys_add(request_keys, "CHAP_I", mutual_chap_i); 669 keys_add(request_keys, "CHAP_C", mutual_chap_c); 670 free(mutual_chap_c); 671 } 672 673 keys_save(request_keys, request); 674 keys_delete(request_keys); 675 pdu_send(request); 676 pdu_delete(request); 677} 678 679static void 680login_verify_mutual(const struct pdu *response) 681{ 682 struct connection *conn; 683 struct keys *response_keys; 684 const char *chap_n, *chap_r; 685 char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH]; 686 size_t response_bin_len; 687 int error; 688 689 conn = response->pdu_connection; 690 691 response_keys = keys_new(); 692 keys_load(response_keys, response); 693 694 chap_n = keys_find(response_keys, "CHAP_N"); 695 if (chap_n == NULL) 696 log_errx(1, "received CHAP Response PDU without CHAP_N"); 697 chap_r = keys_find(response_keys, "CHAP_R"); 698 if (chap_r == NULL) 699 log_errx(1, "received CHAP Response PDU without CHAP_R"); 700 error = login_hex2bin(chap_r, &response_bin, &response_bin_len); 701 if (error != 0) 702 log_errx(1, "received CHAP Response PDU with malformed CHAP_R"); 703 704 if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) { 705 fail(conn, "Mutual CHAP failed"); 706 log_errx(1, "mutual CHAP authentication failed: wrong user"); 707 } 708 709 login_compute_md5(conn->conn_mutual_id, 710 conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge, 711 sizeof(conn->conn_mutual_challenge), expected_response_bin, 712 sizeof(expected_response_bin)); 713 714 if (memcmp(response_bin, expected_response_bin, 715 sizeof(expected_response_bin)) != 0) { 716 fail(conn, "Mutual CHAP failed"); 717 log_errx(1, "mutual CHAP authentication failed: wrong secret"); 718 } 719 720 keys_delete(response_keys); 721 free(response_bin); 722 723 log_debugx("mutual CHAP authentication succeeded"); 724} 725 726static void 727login_chap(struct connection *conn) 728{ 729 struct pdu *response; 730 731 log_debugx("beginning CHAP authentication; sending CHAP_A"); 732 login_send_chap_a(conn); 733 734 log_debugx("waiting for CHAP_A/CHAP_C/CHAP_I"); 735 response = login_receive(conn, false); 736 737 log_debugx("sending CHAP_N/CHAP_R"); 738 login_send_chap_r(response); 739 pdu_delete(response); 740 741 /* 742 * XXX: Make sure this is not susceptible to MITM. 743 */ 744 745 log_debugx("waiting for CHAP result"); 746 response = login_receive(conn, false); 747 if (conn->conn_conf.isc_mutual_user[0] != '\0') 748 login_verify_mutual(response); 749 pdu_delete(response); 750 751 log_debugx("CHAP authentication done"); 752} 753 754void 755login(struct connection *conn) 756{ 757 struct pdu *request, *response; 758 struct keys *request_keys, *response_keys; 759 struct iscsi_bhs_login_request *bhslr; 760 struct iscsi_bhs_login_response *bhslr2; 761 const char *auth_method; 762 int i; 763 764 log_debugx("beginning Login phase; sending Login PDU"); 765 request = login_new_request(conn); 766 767 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 768 769 request_keys = keys_new(); 770 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 771 keys_add(request_keys, "AuthMethod", "CHAP"); 772 } else if (conn->conn_conf.isc_user[0] != '\0') { 773 /* 774 * Give target a chance to skip authentication if it 775 * doesn't feel like it. 776 * 777 * None is first, CHAP second; this is to work around 778 * what seems to be LIO (Linux target) bug: otherwise, 779 * if target is configured with no authentication, 780 * and we are configured to authenticate, the target 781 * will erroneously respond with AuthMethod=CHAP 782 * instead of AuthMethod=None, and will subsequently 783 * fail the connection. This usually happens with 784 * Discovery sessions, which default to no authentication. 785 */ 786 keys_add(request_keys, "AuthMethod", "None,CHAP"); 787 } else { 788 keys_add(request_keys, "AuthMethod", "None"); 789 } 790 keys_add(request_keys, "InitiatorName", 791 conn->conn_conf.isc_initiator); 792 if (conn->conn_conf.isc_initiator_alias[0] != '\0') { 793 keys_add(request_keys, "InitiatorAlias", 794 conn->conn_conf.isc_initiator_alias); 795 } 796 if (conn->conn_conf.isc_discovery == 0) { 797 keys_add(request_keys, "SessionType", "Normal"); 798 keys_add(request_keys, 799 "TargetName", conn->conn_conf.isc_target); 800 } else { 801 keys_add(request_keys, "SessionType", "Discovery"); 802 } 803 keys_save(request_keys, request); 804 keys_delete(request_keys); 805 pdu_send(request); 806 pdu_delete(request); 807 808 response = login_receive(conn, true); 809 810 response_keys = keys_new(); 811 keys_load(response_keys, response); 812 813 for (i = 0; i < KEYS_MAX; i++) { 814 if (response_keys->keys_names[i] == NULL) 815 break; 816 817 /* 818 * Not interested in AuthMethod at this point; we only need 819 * to parse things such as TargetAlias. 820 * 821 * XXX: This is somewhat ugly. We should have a way to apply 822 * all the keys to the session and use that by default 823 * instead of discarding them. 824 */ 825 if (strcmp(response_keys->keys_names[i], "AuthMethod") == 0) 826 continue; 827 828 login_negotiate_key(conn, 829 response_keys->keys_names[i], response_keys->keys_values[i]); 830 } 831 832 bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs; 833 if ((bhslr2->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0 && 834 login_nsg(response) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) { 835 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 836 log_errx(1, "target requested transition " 837 "to operational negotiation, but we require " 838 "mutual CHAP"); 839 } 840 841 log_debugx("target requested transition " 842 "to operational negotiation"); 843 keys_delete(response_keys); 844 pdu_delete(response); 845 login_negotiate(conn); 846 return; 847 } 848 849 auth_method = keys_find(response_keys, "AuthMethod"); 850 if (auth_method == NULL) 851 log_errx(1, "received response without AuthMethod"); 852 if (strcmp(auth_method, "None") == 0) { 853 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 854 log_errx(1, "target does not require authantication, " 855 "but we require mutual CHAP"); 856 } 857 858 log_debugx("target does not require authentication"); 859 keys_delete(response_keys); 860 pdu_delete(response); 861 login_negotiate(conn); 862 return; 863 } 864 865 if (strcmp(auth_method, "CHAP") != 0) { 866 fail(conn, "Unsupported AuthMethod"); 867 log_errx(1, "received response " 868 "with unsupported AuthMethod \"%s\"", auth_method); 869 } 870 871 if (conn->conn_conf.isc_user[0] == '\0' || 872 conn->conn_conf.isc_secret[0] == '\0') { 873 fail(conn, "Authentication required"); 874 log_errx(1, "target requests CHAP authentication, but we don't " 875 "have user and secret"); 876 } 877 878 keys_delete(response_keys); 879 response_keys = NULL; 880 pdu_delete(response); 881 response = NULL; 882 883 login_chap(conn); 884 login_negotiate(conn); 885} 886