login.c revision 269066
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 269066 2014-07-24 15:37:31Z 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) 270{ 271 struct pdu *request; 272 struct iscsi_bhs_login_request *bhslr; 273 274 request = pdu_new(conn); 275 bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs; 276 bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_REQUEST | 277 ISCSI_BHS_OPCODE_IMMEDIATE; 278 bhslr->bhslr_flags = BHSLR_FLAGS_TRANSIT; 279 login_set_csg(request, BHSLR_STAGE_SECURITY_NEGOTIATION); 280 login_set_nsg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 281 memcpy(bhslr->bhslr_isid, &conn->conn_isid, sizeof(bhslr->bhslr_isid)); 282 bhslr->bhslr_tsih = htons(conn->conn_tsih); 283 bhslr->bhslr_initiator_task_tag = 0; 284 bhslr->bhslr_cmdsn = 0; 285 bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1); 286 287 return (request); 288} 289 290static int 291login_list_prefers(const char *list, 292 const char *choice1, const char *choice2) 293{ 294 char *tofree, *str, *token; 295 296 tofree = str = checked_strdup(list); 297 298 while ((token = strsep(&str, ",")) != NULL) { 299 if (strcmp(token, choice1) == 0) { 300 free(tofree); 301 return (1); 302 } 303 if (strcmp(token, choice2) == 0) { 304 free(tofree); 305 return (2); 306 } 307 } 308 free(tofree); 309 return (-1); 310} 311 312static int 313login_hex2int(const char hex) 314{ 315 switch (hex) { 316 case '0': 317 return (0x00); 318 case '1': 319 return (0x01); 320 case '2': 321 return (0x02); 322 case '3': 323 return (0x03); 324 case '4': 325 return (0x04); 326 case '5': 327 return (0x05); 328 case '6': 329 return (0x06); 330 case '7': 331 return (0x07); 332 case '8': 333 return (0x08); 334 case '9': 335 return (0x09); 336 case 'a': 337 case 'A': 338 return (0x0a); 339 case 'b': 340 case 'B': 341 return (0x0b); 342 case 'c': 343 case 'C': 344 return (0x0c); 345 case 'd': 346 case 'D': 347 return (0x0d); 348 case 'e': 349 case 'E': 350 return (0x0e); 351 case 'f': 352 case 'F': 353 return (0x0f); 354 default: 355 return (-1); 356 } 357} 358 359/* 360 * XXX: Review this _carefully_. 361 */ 362static int 363login_hex2bin(const char *hex, char **binp, size_t *bin_lenp) 364{ 365 int i, hex_len, nibble; 366 bool lo = true; /* As opposed to 'hi'. */ 367 char *bin; 368 size_t bin_off, bin_len; 369 370 if (strncasecmp(hex, "0x", strlen("0x")) != 0) { 371 log_warnx("malformed variable, should start with \"0x\""); 372 return (-1); 373 } 374 375 hex += strlen("0x"); 376 hex_len = strlen(hex); 377 if (hex_len < 1) { 378 log_warnx("malformed variable; doesn't contain anything " 379 "but \"0x\""); 380 return (-1); 381 } 382 383 bin_len = hex_len / 2 + hex_len % 2; 384 bin = calloc(bin_len, 1); 385 if (bin == NULL) 386 log_err(1, "calloc"); 387 388 bin_off = bin_len - 1; 389 for (i = hex_len - 1; i >= 0; i--) { 390 nibble = login_hex2int(hex[i]); 391 if (nibble < 0) { 392 log_warnx("malformed variable, invalid char \"%c\"", 393 hex[i]); 394 return (-1); 395 } 396 397 assert(bin_off < bin_len); 398 if (lo) { 399 bin[bin_off] = nibble; 400 lo = false; 401 } else { 402 bin[bin_off] |= nibble << 4; 403 bin_off--; 404 lo = true; 405 } 406 } 407 408 *binp = bin; 409 *bin_lenp = bin_len; 410 return (0); 411} 412 413static char * 414login_bin2hex(const char *bin, size_t bin_len) 415{ 416 unsigned char *hex, *tmp, ch; 417 size_t hex_len; 418 size_t i; 419 420 hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */ 421 hex = malloc(hex_len); 422 if (hex == NULL) 423 log_err(1, "malloc"); 424 425 tmp = hex; 426 tmp += sprintf(tmp, "0x"); 427 for (i = 0; i < bin_len; i++) { 428 ch = bin[i]; 429 tmp += sprintf(tmp, "%02x", ch); 430 } 431 432 return (hex); 433} 434 435static void 436login_compute_md5(const char id, const char *secret, 437 const void *challenge, size_t challenge_len, void *response, 438 size_t response_len) 439{ 440 MD5_CTX ctx; 441 int rv; 442 443 assert(response_len == MD5_DIGEST_LENGTH); 444 445 MD5_Init(&ctx); 446 MD5_Update(&ctx, &id, sizeof(id)); 447 MD5_Update(&ctx, secret, strlen(secret)); 448 MD5_Update(&ctx, challenge, challenge_len); 449 rv = MD5_Final(response, &ctx); 450 if (rv != 1) 451 log_errx(1, "MD5_Final"); 452} 453 454static void 455login_negotiate_key(struct connection *conn, const char *name, 456 const char *value) 457{ 458 int which, tmp; 459 460 if (strcmp(name, "TargetAlias") == 0) { 461 strlcpy(conn->conn_target_alias, value, 462 sizeof(conn->conn_target_alias)); 463 } else if (strcmp(value, "Irrelevant") == 0) { 464 /* Ignore. */ 465 } else if (strcmp(name, "HeaderDigest") == 0) { 466 which = login_list_prefers(value, "CRC32C", "None"); 467 switch (which) { 468 case 1: 469 log_debugx("target prefers CRC32C " 470 "for header digest; we'll use it"); 471 conn->conn_header_digest = CONN_DIGEST_CRC32C; 472 break; 473 case 2: 474 log_debugx("target prefers not to do " 475 "header digest; we'll comply"); 476 break; 477 default: 478 log_warnx("target sent unrecognized " 479 "HeaderDigest value \"%s\"; will use None", value); 480 break; 481 } 482 } else if (strcmp(name, "DataDigest") == 0) { 483 which = login_list_prefers(value, "CRC32C", "None"); 484 switch (which) { 485 case 1: 486 log_debugx("target prefers CRC32C " 487 "for data digest; we'll use it"); 488 conn->conn_data_digest = CONN_DIGEST_CRC32C; 489 break; 490 case 2: 491 log_debugx("target prefers not to do " 492 "data digest; we'll comply"); 493 break; 494 default: 495 log_warnx("target sent unrecognized " 496 "DataDigest value \"%s\"; will use None", value); 497 break; 498 } 499 } else if (strcmp(name, "MaxConnections") == 0) { 500 /* Ignore. */ 501 } else if (strcmp(name, "InitialR2T") == 0) { 502 if (strcmp(value, "Yes") == 0) 503 conn->conn_initial_r2t = true; 504 else 505 conn->conn_initial_r2t = false; 506 } else if (strcmp(name, "ImmediateData") == 0) { 507 if (strcmp(value, "Yes") == 0) 508 conn->conn_immediate_data = true; 509 else 510 conn->conn_immediate_data = false; 511 } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) { 512 tmp = strtoul(value, NULL, 10); 513 if (tmp <= 0) 514 log_errx(1, "received invalid " 515 "MaxRecvDataSegmentLength"); 516 conn->conn_max_data_segment_length = tmp; 517 } else if (strcmp(name, "MaxBurstLength") == 0) { 518 if (conn->conn_immediate_data) { 519 tmp = strtoul(value, NULL, 10); 520 if (tmp <= 0) 521 log_errx(1, "received invalid MaxBurstLength"); 522 conn->conn_max_burst_length = tmp; 523 } 524 } else if (strcmp(name, "FirstBurstLength") == 0) { 525 tmp = strtoul(value, NULL, 10); 526 if (tmp <= 0) 527 log_errx(1, "received invalid FirstBurstLength"); 528 conn->conn_first_burst_length = tmp; 529 } else if (strcmp(name, "DefaultTime2Wait") == 0) { 530 /* Ignore */ 531 } else if (strcmp(name, "DefaultTime2Retain") == 0) { 532 /* Ignore */ 533 } else if (strcmp(name, "MaxOutstandingR2T") == 0) { 534 /* Ignore */ 535 } else if (strcmp(name, "DataPDUInOrder") == 0) { 536 /* Ignore */ 537 } else if (strcmp(name, "DataSequenceInOrder") == 0) { 538 /* Ignore */ 539 } else if (strcmp(name, "ErrorRecoveryLevel") == 0) { 540 /* Ignore */ 541 } else if (strcmp(name, "OFMarker") == 0) { 542 /* Ignore */ 543 } else if (strcmp(name, "IFMarker") == 0) { 544 /* Ignore */ 545 } else if (strcmp(name, "TargetPortalGroupTag") == 0) { 546 /* Ignore */ 547 } else { 548 log_debugx("unknown key \"%s\"; ignoring", name); 549 } 550} 551 552static void 553login_negotiate(struct connection *conn) 554{ 555 struct pdu *request, *response; 556 struct keys *request_keys, *response_keys; 557 struct iscsi_bhs_login_response *bhslr; 558 int i; 559 560 log_debugx("beginning parameter negotiation"); 561 request = login_new_request(conn); 562 login_set_csg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION); 563 login_set_nsg(request, BHSLR_STAGE_FULL_FEATURE_PHASE); 564 request_keys = keys_new(); 565 566 /* 567 * The following keys are irrelevant for discovery sessions. 568 */ 569 if (conn->conn_conf.isc_discovery == 0) { 570 if (conn->conn_conf.isc_header_digest != 0) 571 keys_add(request_keys, "HeaderDigest", "CRC32C"); 572 else 573 keys_add(request_keys, "HeaderDigest", "None"); 574 if (conn->conn_conf.isc_data_digest != 0) 575 keys_add(request_keys, "DataDigest", "CRC32C"); 576 else 577 keys_add(request_keys, "DataDigest", "None"); 578 579 keys_add(request_keys, "ImmediateData", "Yes"); 580 keys_add_int(request_keys, "MaxBurstLength", 581 ISCSI_MAX_DATA_SEGMENT_LENGTH); 582 keys_add_int(request_keys, "FirstBurstLength", 583 ISCSI_MAX_DATA_SEGMENT_LENGTH); 584 keys_add(request_keys, "InitialR2T", "Yes"); 585 } else { 586 keys_add(request_keys, "HeaderDigest", "None"); 587 keys_add(request_keys, "DataDigest", "None"); 588 } 589 590 keys_add_int(request_keys, "MaxRecvDataSegmentLength", 591 ISCSI_MAX_DATA_SEGMENT_LENGTH); 592 keys_add(request_keys, "DefaultTime2Wait", "0"); 593 keys_add(request_keys, "DefaultTime2Retain", "0"); 594 keys_add(request_keys, "ErrorRecoveryLevel", "0"); 595 keys_add(request_keys, "MaxOutstandingR2T", "1"); 596 keys_save(request_keys, request); 597 keys_delete(request_keys); 598 request_keys = NULL; 599 pdu_send(request); 600 pdu_delete(request); 601 request = NULL; 602 603 response = login_receive(conn, false); 604 response_keys = keys_new(); 605 keys_load(response_keys, response); 606 for (i = 0; i < KEYS_MAX; i++) { 607 if (response_keys->keys_names[i] == NULL) 608 break; 609 610 login_negotiate_key(conn, 611 response_keys->keys_names[i], response_keys->keys_values[i]); 612 } 613 614 bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs; 615 if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0) 616 log_warnx("received final login response " 617 "without the \"T\" flag"); 618 else if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE) 619 log_warnx("received final login response with wrong NSG 0x%x", 620 login_nsg(response)); 621 622 log_debugx("parameter negotiation done; " 623 "transitioning to Full Feature phase"); 624 625 keys_delete(response_keys); 626 pdu_delete(response); 627} 628 629static void 630login_send_chap_a(struct connection *conn) 631{ 632 struct pdu *request; 633 struct keys *request_keys; 634 635 request = login_new_request(conn); 636 request_keys = keys_new(); 637 keys_add(request_keys, "CHAP_A", "5"); 638 keys_save(request_keys, request); 639 keys_delete(request_keys); 640 pdu_send(request); 641 pdu_delete(request); 642} 643 644static void 645login_send_chap_r(struct pdu *response) 646{ 647 struct connection *conn; 648 struct pdu *request; 649 struct keys *request_keys, *response_keys; 650 const char *chap_a, *chap_c, *chap_i; 651 char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH]; 652 size_t challenge_len; 653 int error, rv; 654 unsigned char id; 655 char *mutual_chap_c, mutual_chap_i[4]; 656 657 /* 658 * As in the rest of the initiator, 'request' means 659 * 'initiator -> target', and 'response' means 'target -> initiator', 660 * 661 * So, here the 'response' from the target is the packet that contains 662 * CHAP challenge; our CHAP response goes into 'request'. 663 */ 664 665 conn = response->pdu_connection; 666 667 response_keys = keys_new(); 668 keys_load(response_keys, response); 669 670 /* 671 * First, compute the response. 672 */ 673 chap_a = keys_find(response_keys, "CHAP_A"); 674 if (chap_a == NULL) 675 log_errx(1, "received CHAP packet without CHAP_A"); 676 chap_c = keys_find(response_keys, "CHAP_C"); 677 if (chap_c == NULL) 678 log_errx(1, "received CHAP packet without CHAP_C"); 679 chap_i = keys_find(response_keys, "CHAP_I"); 680 if (chap_i == NULL) 681 log_errx(1, "received CHAP packet without CHAP_I"); 682 683 if (strcmp(chap_a, "5") != 0) 684 log_errx(1, "received CHAP packet " 685 "with unsupported CHAP_A \"%s\"", chap_a); 686 id = strtoul(chap_i, NULL, 10); 687 error = login_hex2bin(chap_c, &challenge, &challenge_len); 688 if (error != 0) 689 log_errx(1, "received CHAP packet with malformed CHAP_C"); 690 login_compute_md5(id, conn->conn_conf.isc_secret, 691 challenge, challenge_len, response_bin, sizeof(response_bin)); 692 free(challenge); 693 chap_r = login_bin2hex(response_bin, sizeof(response_bin)); 694 695 keys_delete(response_keys); 696 697 request = login_new_request(conn); 698 request_keys = keys_new(); 699 keys_add(request_keys, "CHAP_N", conn->conn_conf.isc_user); 700 keys_add(request_keys, "CHAP_R", chap_r); 701 free(chap_r); 702 703 /* 704 * If we want mutual authentication, we're expected to send 705 * our CHAP_I/CHAP_C now. 706 */ 707 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 708 log_debugx("requesting mutual authentication; " 709 "binary challenge size is %zd bytes", 710 sizeof(conn->conn_mutual_challenge)); 711 712 rv = RAND_bytes(conn->conn_mutual_challenge, 713 sizeof(conn->conn_mutual_challenge)); 714 if (rv != 1) { 715 log_errx(1, "RAND_bytes failed: %s", 716 ERR_error_string(ERR_get_error(), NULL)); 717 } 718 rv = RAND_bytes(&conn->conn_mutual_id, 719 sizeof(conn->conn_mutual_id)); 720 if (rv != 1) { 721 log_errx(1, "RAND_bytes failed: %s", 722 ERR_error_string(ERR_get_error(), NULL)); 723 } 724 mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge, 725 sizeof(conn->conn_mutual_challenge)); 726 snprintf(mutual_chap_i, sizeof(mutual_chap_i), 727 "%d", conn->conn_mutual_id); 728 keys_add(request_keys, "CHAP_I", mutual_chap_i); 729 keys_add(request_keys, "CHAP_C", mutual_chap_c); 730 free(mutual_chap_c); 731 } 732 733 keys_save(request_keys, request); 734 keys_delete(request_keys); 735 pdu_send(request); 736 pdu_delete(request); 737} 738 739static void 740login_verify_mutual(const struct pdu *response) 741{ 742 struct connection *conn; 743 struct keys *response_keys; 744 const char *chap_n, *chap_r; 745 char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH]; 746 size_t response_bin_len; 747 int error; 748 749 conn = response->pdu_connection; 750 751 response_keys = keys_new(); 752 keys_load(response_keys, response); 753 754 chap_n = keys_find(response_keys, "CHAP_N"); 755 if (chap_n == NULL) 756 log_errx(1, "received CHAP Response PDU without CHAP_N"); 757 chap_r = keys_find(response_keys, "CHAP_R"); 758 if (chap_r == NULL) 759 log_errx(1, "received CHAP Response PDU without CHAP_R"); 760 error = login_hex2bin(chap_r, &response_bin, &response_bin_len); 761 if (error != 0) 762 log_errx(1, "received CHAP Response PDU with malformed CHAP_R"); 763 764 if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) { 765 fail(conn, "Mutual CHAP failed"); 766 log_errx(1, "mutual CHAP authentication failed: wrong user"); 767 } 768 769 login_compute_md5(conn->conn_mutual_id, 770 conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge, 771 sizeof(conn->conn_mutual_challenge), expected_response_bin, 772 sizeof(expected_response_bin)); 773 774 if (memcmp(response_bin, expected_response_bin, 775 sizeof(expected_response_bin)) != 0) { 776 fail(conn, "Mutual CHAP failed"); 777 log_errx(1, "mutual CHAP authentication failed: wrong secret"); 778 } 779 780 keys_delete(response_keys); 781 free(response_bin); 782 783 log_debugx("mutual CHAP authentication succeeded"); 784} 785 786static void 787login_chap(struct connection *conn) 788{ 789 struct pdu *response; 790 791 log_debugx("beginning CHAP authentication; sending CHAP_A"); 792 login_send_chap_a(conn); 793 794 log_debugx("waiting for CHAP_A/CHAP_C/CHAP_I"); 795 response = login_receive(conn, false); 796 797 log_debugx("sending CHAP_N/CHAP_R"); 798 login_send_chap_r(response); 799 pdu_delete(response); 800 801 /* 802 * XXX: Make sure this is not susceptible to MITM. 803 */ 804 805 log_debugx("waiting for CHAP result"); 806 response = login_receive(conn, false); 807 if (conn->conn_conf.isc_mutual_user[0] != '\0') 808 login_verify_mutual(response); 809 pdu_delete(response); 810 811 log_debugx("CHAP authentication done"); 812} 813 814void 815login(struct connection *conn) 816{ 817 struct pdu *request, *response; 818 struct keys *request_keys, *response_keys; 819 struct iscsi_bhs_login_response *bhslr2; 820 const char *auth_method; 821 int i; 822 823 log_debugx("beginning Login phase; sending Login PDU"); 824 request = login_new_request(conn); 825 request_keys = keys_new(); 826 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 827 keys_add(request_keys, "AuthMethod", "CHAP"); 828 } else if (conn->conn_conf.isc_user[0] != '\0') { 829 /* 830 * Give target a chance to skip authentication if it 831 * doesn't feel like it. 832 * 833 * None is first, CHAP second; this is to work around 834 * what seems to be LIO (Linux target) bug: otherwise, 835 * if target is configured with no authentication, 836 * and we are configured to authenticate, the target 837 * will erroneously respond with AuthMethod=CHAP 838 * instead of AuthMethod=None, and will subsequently 839 * fail the connection. This usually happens with 840 * Discovery sessions, which default to no authentication. 841 */ 842 keys_add(request_keys, "AuthMethod", "None,CHAP"); 843 } else { 844 keys_add(request_keys, "AuthMethod", "None"); 845 } 846 keys_add(request_keys, "InitiatorName", 847 conn->conn_conf.isc_initiator); 848 if (conn->conn_conf.isc_initiator_alias[0] != '\0') { 849 keys_add(request_keys, "InitiatorAlias", 850 conn->conn_conf.isc_initiator_alias); 851 } 852 if (conn->conn_conf.isc_discovery == 0) { 853 keys_add(request_keys, "SessionType", "Normal"); 854 keys_add(request_keys, 855 "TargetName", conn->conn_conf.isc_target); 856 } else { 857 keys_add(request_keys, "SessionType", "Discovery"); 858 } 859 keys_save(request_keys, request); 860 keys_delete(request_keys); 861 pdu_send(request); 862 pdu_delete(request); 863 864 response = login_receive(conn, true); 865 866 response_keys = keys_new(); 867 keys_load(response_keys, response); 868 869 for (i = 0; i < KEYS_MAX; i++) { 870 if (response_keys->keys_names[i] == NULL) 871 break; 872 873 /* 874 * Not interested in AuthMethod at this point; we only need 875 * to parse things such as TargetAlias. 876 * 877 * XXX: This is somewhat ugly. We should have a way to apply 878 * all the keys to the session and use that by default 879 * instead of discarding them. 880 */ 881 if (strcmp(response_keys->keys_names[i], "AuthMethod") == 0) 882 continue; 883 884 login_negotiate_key(conn, 885 response_keys->keys_names[i], response_keys->keys_values[i]); 886 } 887 888 bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs; 889 if ((bhslr2->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0 && 890 login_nsg(response) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) { 891 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 892 log_errx(1, "target requested transition " 893 "to operational negotiation, but we require " 894 "mutual CHAP"); 895 } 896 897 log_debugx("target requested transition " 898 "to operational negotiation"); 899 keys_delete(response_keys); 900 pdu_delete(response); 901 login_negotiate(conn); 902 return; 903 } 904 905 auth_method = keys_find(response_keys, "AuthMethod"); 906 if (auth_method == NULL) 907 log_errx(1, "received response without AuthMethod"); 908 if (strcmp(auth_method, "None") == 0) { 909 if (conn->conn_conf.isc_mutual_user[0] != '\0') { 910 log_errx(1, "target does not require authantication, " 911 "but we require mutual CHAP"); 912 } 913 914 log_debugx("target does not require authentication"); 915 keys_delete(response_keys); 916 pdu_delete(response); 917 login_negotiate(conn); 918 return; 919 } 920 921 if (strcmp(auth_method, "CHAP") != 0) { 922 fail(conn, "Unsupported AuthMethod"); 923 log_errx(1, "received response " 924 "with unsupported AuthMethod \"%s\"", auth_method); 925 } 926 927 if (conn->conn_conf.isc_user[0] == '\0' || 928 conn->conn_conf.isc_secret[0] == '\0') { 929 fail(conn, "Authentication required"); 930 log_errx(1, "target requests CHAP authentication, but we don't " 931 "have user and secret"); 932 } 933 934 keys_delete(response_keys); 935 response_keys = NULL; 936 pdu_delete(response); 937 response = NULL; 938 939 login_chap(conn); 940 login_negotiate(conn); 941} 942