usr.sbin/iscsid/login.c

   1 /*-
   2  * Copyright (c) 2012 The FreeBSD Foundation
   3  * All rights reserved.
   4  *
   5  * This software was developed by Edward Tomasz Napierala under sponsorship
   6  * from the FreeBSD Foundation.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD$
  30  */
  31
  32 #include <sys/types.h>
  33 #include <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
  46 static int
  47 login_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
  56 static void
  57 login_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
  71 static void
  72 login_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
  86 static const char *
  87 login_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
 161 static struct pdu *
 162 login_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_statsn = ntohl(bhslr->bhslr_statsn);
 203
 204         return (response);
 205 }
 206
 207 static struct pdu *
 208 login_new_request(struct connection *conn)
 209 {
 210         struct pdu *request;
 211         struct iscsi_bhs_login_request *bhslr;
 212
 213         request = pdu_new(conn);
 214         bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
 215         bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_REQUEST |
 216             ISCSI_BHS_OPCODE_IMMEDIATE;
 217         bhslr->bhslr_flags = BHSLR_FLAGS_TRANSIT;
 218         login_set_csg(request, BHSLR_STAGE_SECURITY_NEGOTIATION);
 219         login_set_nsg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
 220         memcpy(bhslr->bhslr_isid, &conn->conn_isid, sizeof(bhslr->bhslr_isid));
 221         bhslr->bhslr_initiator_task_tag = 0;
 222         bhslr->bhslr_cmdsn = 0;
 223         bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1);
 224
 225         return (request);
 226 }
 227
 228 static int
 229 login_list_prefers(const char *list,
 230     const char *choice1, const char *choice2)
 231 {
 232         char *tofree, *str, *token;
 233
 234         tofree = str = checked_strdup(list);
 235
 236         while ((token = strsep(&str, ",")) != NULL) {
 237                 if (strcmp(token, choice1) == 0) {
 238                         free(tofree);
 239                         return (1);
 240                 }
 241                 if (strcmp(token, choice2) == 0) {
 242                         free(tofree);
 243                         return (2);
 244                 }
 245         }
 246         free(tofree);
 247         return (-1);
 248 }
 249
 250 static int
 251 login_hex2int(const char hex)
 252 {
 253         switch (hex) {
 254         case '0':
 255                 return (0x00);
 256         case '1':
 257                 return (0x01);
 258         case '2':
 259                 return (0x02);
 260         case '3':
 261                 return (0x03);
 262         case '4':
 263                 return (0x04);
 264         case '5':
 265                 return (0x05);
 266         case '6':
 267                 return (0x06);
 268         case '7':
 269                 return (0x07);
 270         case '8':
 271                 return (0x08);
 272         case '9':
 273                 return (0x09);
 274         case 'a':
 275         case 'A':
 276                 return (0x0a);
 277         case 'b':
 278         case 'B':
 279                 return (0x0b);
 280         case 'c':
 281         case 'C':
 282                 return (0x0c);
 283         case 'd':
 284         case 'D':
 285                 return (0x0d);
 286         case 'e':
 287         case 'E':
 288                 return (0x0e);
 289         case 'f':
 290         case 'F':
 291                 return (0x0f);
 292         default:
 293                 return (-1);
 294         }
 295 }
 296
 297 /*
 298  * XXX: Review this _carefully_.
 299  */
 300 static int
 301 login_hex2bin(const char *hex, char **binp, size_t *bin_lenp)
 302 {
 303         int i, hex_len, nibble;
 304         bool lo = true; /* As opposed to 'hi'. */
 305         char *bin;
 306         size_t bin_off, bin_len;
 307
 308         if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
 309                 log_warnx("malformed variable, should start with \"0x\"");
 310                 return (-1);
 311         }
 312
 313         hex += strlen("0x");
 314         hex_len = strlen(hex);
 315         if (hex_len < 1) {
 316                 log_warnx("malformed variable; doesn't contain anything "
 317                     "but \"0x\"");
 318                 return (-1);
 319         }
 320
 321         bin_len = hex_len / 2 + hex_len % 2;
 322         bin = calloc(bin_len, 1);
 323         if (bin == NULL)
 324                 log_err(1, "calloc");
 325
 326         bin_off = bin_len - 1;
 327         for (i = hex_len - 1; i >= 0; i--) {
 328                 nibble = login_hex2int(hex[i]);
 329                 if (nibble < 0) {
 330                         log_warnx("malformed variable, invalid char \"%c\"",
 331                             hex[i]);
 332                         return (-1);
 333                 }
 334
 335                 assert(bin_off < bin_len);
 336                 if (lo) {
 337                         bin[bin_off] = nibble;
 338                         lo = false;
 339                 } else {
 340                         bin[bin_off] |= nibble << 4;
 341                         bin_off--;
 342                         lo = true;
 343                 }
 344         }
 345
 346         *binp = bin;
 347         *bin_lenp = bin_len;
 348         return (0);
 349 }
 350
 351 static char *
 352 login_bin2hex(const char *bin, size_t bin_len)
 353 {
 354         unsigned char *hex, *tmp, ch;
 355         size_t hex_len;
 356         size_t i;
 357
 358         hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
 359         hex = malloc(hex_len);
 360         if (hex == NULL)
 361                 log_err(1, "malloc");
 362
 363         tmp = hex;
 364         tmp += sprintf(tmp, "0x");
 365         for (i = 0; i < bin_len; i++) {
 366                 ch = bin[i];
 367                 tmp += sprintf(tmp, "%02x", ch);
 368         }
 369
 370         return (hex);
 371 }
 372
 373 static void
 374 login_compute_md5(const char id, const char *secret,
 375     const void *challenge, size_t challenge_len, void *response,
 376     size_t response_len)
 377 {
 378         MD5_CTX ctx;
 379         int rv;
 380
 381         assert(response_len == MD5_DIGEST_LENGTH);
 382
 383         MD5_Init(&ctx);
 384         MD5_Update(&ctx, &id, sizeof(id));
 385         MD5_Update(&ctx, secret, strlen(secret));
 386         MD5_Update(&ctx, challenge, challenge_len);
 387         rv = MD5_Final(response, &ctx);
 388         if (rv != 1)
 389                 log_errx(1, "MD5_Final");
 390 }
 391
 392 static void
 393 login_negotiate_key(struct connection *conn, const char *name,
 394     const char *value)
 395 {
 396         int which, tmp;
 397
 398         if (strcmp(name, "TargetAlias") == 0) {
 399                 strlcpy(conn->conn_target_alias, value,
 400                     sizeof(conn->conn_target_alias));
 401         } else if (strcmp(value, "Irrelevant") == 0) {
 402                 /* Ignore. */
 403         } else if (strcmp(name, "HeaderDigest") == 0) {
 404                 which = login_list_prefers(value, "CRC32C", "None");
 405                 switch (which) {
 406                 case 1:
 407                         log_debugx("target prefers CRC32C "
 408                             "for header digest; we'll use it");
 409                         conn->conn_header_digest = CONN_DIGEST_CRC32C;
 410                         break;
 411                 case 2:
 412                         log_debugx("target prefers not to do "
 413                             "header digest; we'll comply");
 414                         break;
 415                 default:
 416                         log_warnx("target sent unrecognized "
 417                             "HeaderDigest value \"%s\"; will use None", value);
 418                         break;
 419                 }
 420         } else if (strcmp(name, "DataDigest") == 0) {
 421                 which = login_list_prefers(value, "CRC32C", "None");
 422                 switch (which) {
 423                 case 1:
 424                         log_debugx("target prefers CRC32C "
 425                             "for data digest; we'll use it");
 426                         conn->conn_data_digest = CONN_DIGEST_CRC32C;
 427                         break;
 428                 case 2:
 429                         log_debugx("target prefers not to do "
 430                             "data digest; we'll comply");
 431                         break;
 432                 default:
 433                         log_warnx("target sent unrecognized "
 434                             "DataDigest value \"%s\"; will use None", value);
 435                         break;
 436                 }
 437         } else if (strcmp(name, "MaxConnections") == 0) {
 438                 /* Ignore. */
 439         } else if (strcmp(name, "InitialR2T") == 0) {
 440                 if (strcmp(value, "Yes") == 0)
 441                         conn->conn_initial_r2t = true;
 442                 else
 443                         conn->conn_initial_r2t = false;
 444         } else if (strcmp(name, "ImmediateData") == 0) {
 445                 if (strcmp(value, "Yes") == 0)
 446                         conn->conn_immediate_data = true;
 447                 else
 448                         conn->conn_immediate_data = false;
 449         } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) {
 450                 tmp = strtoul(value, NULL, 10);
 451                 if (tmp <= 0)
 452                         log_errx(1, "received invalid "
 453                             "MaxRecvDataSegmentLength");
 454                 conn->conn_max_data_segment_length = tmp;
 455         } else if (strcmp(name, "MaxBurstLength") == 0) {
 456                 if (conn->conn_immediate_data) {
 457                         tmp = strtoul(value, NULL, 10);
 458                         if (tmp <= 0)
 459                                 log_errx(1, "received invalid MaxBurstLength");
 460                         conn->conn_max_burst_length = tmp;
 461                 }
 462         } else if (strcmp(name, "FirstBurstLength") == 0) {
 463                 tmp = strtoul(value, NULL, 10);
 464                 if (tmp <= 0)
 465                         log_errx(1, "received invalid FirstBurstLength");
 466                 conn->conn_first_burst_length = tmp;
 467         } else if (strcmp(name, "DefaultTime2Wait") == 0) {
 468                 /* Ignore */
 469         } else if (strcmp(name, "DefaultTime2Retain") == 0) {
 470                 /* Ignore */
 471         } else if (strcmp(name, "MaxOutstandingR2T") == 0) {
 472                 /* Ignore */
 473         } else if (strcmp(name, "DataPDUInOrder") == 0) {
 474                 /* Ignore */
 475         } else if (strcmp(name, "DataSequenceInOrder") == 0) {
 476                 /* Ignore */
 477         } else if (strcmp(name, "ErrorRecoveryLevel") == 0) {
 478                 /* Ignore */
 479         } else if (strcmp(name, "OFMarker") == 0) {
 480                 /* Ignore */
 481         } else if (strcmp(name, "IFMarker") == 0) {
 482                 /* Ignore */
 483         } else if (strcmp(name, "TargetPortalGroupTag") == 0) {
 484                 /* Ignore */
 485         } else {
 486                 log_debugx("unknown key \"%s\"; ignoring",  name);
 487         }
 488 }
 489
 490 static void
 491 login_negotiate(struct connection *conn)
 492 {
 493         struct pdu *request, *response;
 494         struct keys *request_keys, *response_keys;
 495         struct iscsi_bhs_login_response *bhslr;
 496         int i;
 497
 498         log_debugx("beginning parameter negotiation");
 499         request = login_new_request(conn);
 500         login_set_csg(request, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
 501         login_set_nsg(request, BHSLR_STAGE_FULL_FEATURE_PHASE);
 502         request_keys = keys_new();
 503
 504         /*
 505          * The following keys are irrelevant for discovery sessions.
 506          */
 507         if (conn->conn_conf.isc_discovery == 0) {
 508                 if (conn->conn_conf.isc_header_digest != 0)
 509                         keys_add(request_keys, "HeaderDigest", "CRC32C");
 510                 else
 511                         keys_add(request_keys, "HeaderDigest", "None");
 512                 if (conn->conn_conf.isc_data_digest != 0)
 513                         keys_add(request_keys, "DataDigest", "CRC32C");
 514                 else
 515                         keys_add(request_keys, "DataDigest", "None");
 516
 517                 keys_add(request_keys, "ImmediateData", "Yes");
 518                 keys_add_int(request_keys, "MaxBurstLength",
 519                     ISCSI_MAX_DATA_SEGMENT_LENGTH);
 520                 keys_add_int(request_keys, "FirstBurstLength",
 521                     ISCSI_MAX_DATA_SEGMENT_LENGTH);
 522                 keys_add(request_keys, "InitialR2T", "Yes");
 523         } else {
 524                 keys_add(request_keys, "HeaderDigest", "None");
 525                 keys_add(request_keys, "DataDigest", "None");
 526         }
 527
 528         keys_add_int(request_keys, "MaxRecvDataSegmentLength",
 529             ISCSI_MAX_DATA_SEGMENT_LENGTH);
 530         keys_add(request_keys, "DefaultTime2Wait", "0");
 531         keys_add(request_keys, "DefaultTime2Retain", "0");
 532         keys_add(request_keys, "ErrorRecoveryLevel", "0");
 533         keys_add(request_keys, "MaxOutstandingR2T", "1");
 534         keys_save(request_keys, request);
 535         keys_delete(request_keys);
 536         request_keys = NULL;
 537         pdu_send(request);
 538         pdu_delete(request);
 539         request = NULL;
 540
 541         response = login_receive(conn, false);
 542         response_keys = keys_new();
 543         keys_load(response_keys, response);
 544         for (i = 0; i < KEYS_MAX; i++) {
 545                 if (response_keys->keys_names[i] == NULL)
 546                         break;
 547
 548                 login_negotiate_key(conn,
 549                     response_keys->keys_names[i], response_keys->keys_values[i]);
 550         }
 551
 552         bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs;
 553         if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0)
 554                 log_warnx("received final login response "
 555                     "without the \"T\" flag");
 556         else if (login_nsg(response) != BHSLR_STAGE_FULL_FEATURE_PHASE)
 557                 log_warnx("received final login response with wrong NSG 0x%x",
 558                     login_nsg(response));
 559
 560         log_debugx("parameter negotiation done; "
 561             "transitioning to Full Feature phase");
 562
 563         keys_delete(response_keys);
 564         pdu_delete(response);
 565 }
 566
 567 static void
 568 login_send_chap_a(struct connection *conn)
 569 {
 570         struct pdu *request;
 571         struct keys *request_keys;
 572
 573         request = login_new_request(conn);
 574         request_keys = keys_new();
 575         keys_add(request_keys, "CHAP_A", "5");
 576         keys_save(request_keys, request);
 577         keys_delete(request_keys);
 578         pdu_send(request);
 579         pdu_delete(request);
 580 }
 581
 582 static void
 583 login_send_chap_r(struct pdu *response)
 584 {
 585         struct connection *conn;
 586         struct pdu *request;
 587         struct keys *request_keys, *response_keys;
 588         const char *chap_a, *chap_c, *chap_i;
 589         char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH];
 590         size_t challenge_len;
 591         int error, rv;
 592         unsigned char id;
 593         char *mutual_chap_c, mutual_chap_i[4];
 594
 595         /*
 596          * As in the rest of the initiator, 'request' means
 597          * 'initiator -> target', and 'response' means 'target -> initiator',
 598          *
 599          * So, here the 'response' from the target is the packet that contains
 600          * CHAP challenge; our CHAP response goes into 'request'.
 601          */
 602
 603         conn = response->pdu_connection;
 604
 605         response_keys = keys_new();
 606         keys_load(response_keys, response);
 607
 608         /*
 609          * First, compute the response.
 610          */
 611         chap_a = keys_find(response_keys, "CHAP_A");
 612         if (chap_a == NULL)
 613                 log_errx(1, "received CHAP packet without CHAP_A");
 614         chap_c = keys_find(response_keys, "CHAP_C");
 615         if (chap_c == NULL)
 616                 log_errx(1, "received CHAP packet without CHAP_C");
 617         chap_i = keys_find(response_keys, "CHAP_I");
 618         if (chap_i == NULL)
 619                 log_errx(1, "received CHAP packet without CHAP_I");
 620
 621         if (strcmp(chap_a, "5") != 0)
 622                 log_errx(1, "received CHAP packet "
 623                     "with unsupported CHAP_A \"%s\"", chap_a);
 624         id = strtoul(chap_i, NULL, 10);
 625         error = login_hex2bin(chap_c, &challenge, &challenge_len);
 626         if (error != 0)
 627                 log_errx(1, "received CHAP packet with malformed CHAP_C");
 628         login_compute_md5(id, conn->conn_conf.isc_secret,
 629             challenge, challenge_len, response_bin, sizeof(response_bin));
 630         free(challenge);
 631         chap_r = login_bin2hex(response_bin, sizeof(response_bin));
 632
 633         keys_delete(response_keys);
 634
 635         request = login_new_request(conn);
 636         request_keys = keys_new();
 637         keys_add(request_keys, "CHAP_N", conn->conn_conf.isc_user);
 638         keys_add(request_keys, "CHAP_R", chap_r);
 639         free(chap_r);
 640
 641         /*
 642          * If we want mutual authentication, we're expected to send
 643          * our CHAP_I/CHAP_C now.
 644          */
 645         if (conn->conn_conf.isc_mutual_user[0] != '\0') {
 646                 log_debugx("requesting mutual authentication; "
 647                     "binary challenge size is %zd bytes",
 648                     sizeof(conn->conn_mutual_challenge));
 649
 650                 rv = RAND_bytes(conn->conn_mutual_challenge,
 651                     sizeof(conn->conn_mutual_challenge));
 652                 if (rv != 1) {
 653                         log_errx(1, "RAND_bytes failed: %s",
 654                             ERR_error_string(ERR_get_error(), NULL));
 655                 }
 656                 rv = RAND_bytes(&conn->conn_mutual_id,
 657                     sizeof(conn->conn_mutual_id));
 658                 if (rv != 1) {
 659                         log_errx(1, "RAND_bytes failed: %s",
 660                             ERR_error_string(ERR_get_error(), NULL));
 661                 }
 662                 mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge,
 663                     sizeof(conn->conn_mutual_challenge));
 664                 snprintf(mutual_chap_i, sizeof(mutual_chap_i),
 665                     "%d", conn->conn_mutual_id);
 666                 keys_add(request_keys, "CHAP_I", mutual_chap_i);
 667                 keys_add(request_keys, "CHAP_C", mutual_chap_c);
 668                 free(mutual_chap_c);
 669         }
 670
 671         keys_save(request_keys, request);
 672         keys_delete(request_keys);
 673         pdu_send(request);
 674         pdu_delete(request);
 675 }
 676
 677 static void
 678 login_verify_mutual(const struct pdu *response)
 679 {
 680         struct connection *conn;
 681         struct keys *response_keys;
 682         const char *chap_n, *chap_r;
 683         char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH];
 684         size_t response_bin_len;
 685         int error;
 686
 687         conn = response->pdu_connection;
 688
 689         response_keys = keys_new();
 690         keys_load(response_keys, response);
 691
 692         chap_n = keys_find(response_keys, "CHAP_N");
 693         if (chap_n == NULL)
 694                 log_errx(1, "received CHAP Response PDU without CHAP_N");
 695         chap_r = keys_find(response_keys, "CHAP_R");
 696         if (chap_r == NULL)
 697                 log_errx(1, "received CHAP Response PDU without CHAP_R");
 698         error = login_hex2bin(chap_r, &response_bin, &response_bin_len);
 699         if (error != 0)
 700                 log_errx(1, "received CHAP Response PDU with malformed CHAP_R");
 701
 702         if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) {
 703                 fail(conn, "Mutual CHAP failed");
 704                 log_errx(1, "mutual CHAP authentication failed: wrong user");
 705         }
 706
 707         login_compute_md5(conn->conn_mutual_id,
 708             conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge,
 709             sizeof(conn->conn_mutual_challenge), expected_response_bin,
 710             sizeof(expected_response_bin));
 711
 712         if (memcmp(response_bin, expected_response_bin,
 713             sizeof(expected_response_bin)) != 0) {
 714                 fail(conn, "Mutual CHAP failed");
 715                 log_errx(1, "mutual CHAP authentication failed: wrong secret");
 716         }
 717
 718         keys_delete(response_keys);
 719         free(response_bin);
 720
 721         log_debugx("mutual CHAP authentication succeeded");
 722 }
 723
 724 static void
 725 login_chap(struct connection *conn)
 726 {
 727         struct pdu *response;
 728
 729         log_debugx("beginning CHAP authentication; sending CHAP_A");
 730         login_send_chap_a(conn);
 731
 732         log_debugx("waiting for CHAP_A/CHAP_C/CHAP_I");
 733         response = login_receive(conn, false);
 734
 735         log_debugx("sending CHAP_N/CHAP_R");
 736         login_send_chap_r(response);
 737         pdu_delete(response);
 738
 739         /*
 740          * XXX: Make sure this is not susceptible to MITM.
 741          */
 742
 743         log_debugx("waiting for CHAP result");
 744         response = login_receive(conn, false);
 745         if (conn->conn_conf.isc_mutual_user[0] != '\0')
 746                 login_verify_mutual(response);
 747         pdu_delete(response);
 748
 749         log_debugx("CHAP authentication done");
 750 }
 751
 752 static void
 753 login_create_isid(struct connection *conn)
 754 {
 755         int rv;
 756
 757         /*
 758          * RFC 3720, 10.12.5: 10b, "Random" ISID.
 759          *
 760          */
 761         conn->conn_isid[0] = 0x80;
 762
 763         rv = RAND_bytes(&conn->conn_isid[1], 3);
 764         if (rv != 1) {
 765                 log_errx(1, "RAND_bytes failed: %s",
 766                     ERR_error_string(ERR_get_error(), NULL));
 767         }
 768 }
 769
 770 void
 771 login(struct connection *conn)
 772 {
 773         struct pdu *request, *response;
 774         struct keys *request_keys, *response_keys;
 775         struct iscsi_bhs_login_request *bhslr;
 776         struct iscsi_bhs_login_response *bhslr2;
 777         const char *auth_method;
 778         int i;
 779
 780         login_create_isid(conn);
 781
 782         log_debugx("beginning Login phase; sending Login PDU");
 783         request = login_new_request(conn);
 784
 785         bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
 786         bhslr->bhslr_flags |= BHSLR_FLAGS_TRANSIT;
 787
 788         request_keys = keys_new();
 789         if (conn->conn_conf.isc_mutual_user[0] != '\0') {
 790                 keys_add(request_keys, "AuthMethod", "CHAP");
 791         } else if (conn->conn_conf.isc_user[0] != '\0') {
 792                 /*
 793                  * Give target a chance to skip authentication if it
 794                  * doesn't feel like it.
 795                  *
 796                  * None is first, CHAP second; this is to work around
 797                  * what seems to be LIO (Linux target) bug: otherwise,
 798                  * if target is configured with no authentication,
 799                  * and we are configured to authenticate, the target
 800                  * will erroneously respond with AuthMethod=CHAP
 801                  * instead of AuthMethod=None, and will subsequently
 802                  * fail the connection.  This usually happens with
 803                  * Discovery sessions, which default to no authentication.
 804                  */
 805                 keys_add(request_keys, "AuthMethod", "None,CHAP");
 806         } else {
 807                 keys_add(request_keys, "AuthMethod", "None");
 808         }
 809         keys_add(request_keys, "InitiatorName",
 810             conn->conn_conf.isc_initiator);
 811         if (conn->conn_conf.isc_initiator_alias[0] != '\0') {
 812                 keys_add(request_keys, "InitiatorAlias",
 813                     conn->conn_conf.isc_initiator_alias);
 814         }
 815         if (conn->conn_conf.isc_discovery == 0) {
 816                 keys_add(request_keys, "SessionType", "Normal");
 817                 keys_add(request_keys,
 818                     "TargetName", conn->conn_conf.isc_target);
 819         } else {
 820                 keys_add(request_keys, "SessionType", "Discovery");
 821         }
 822         keys_save(request_keys, request);
 823         keys_delete(request_keys);
 824         pdu_send(request);
 825         pdu_delete(request);
 826
 827         response = login_receive(conn, true);
 828
 829         response_keys = keys_new();
 830         keys_load(response_keys, response);
 831
 832         for (i = 0; i < KEYS_MAX; i++) {
 833                 if (response_keys->keys_names[i] == NULL)
 834                         break;
 835
 836                 /*
 837                  * Not interested in AuthMethod at this point; we only need
 838                  * to parse things such as TargetAlias.
 839                  *
 840                  * XXX: This is somewhat ugly.  We should have a way to apply
 841                  *      all the keys to the session and use that by default
 842                  *      instead of discarding them.
 843                  */
 844                 if (strcmp(response_keys->keys_names[i], "AuthMethod") == 0)
 845                         continue;
 846
 847                 login_negotiate_key(conn,
 848                     response_keys->keys_names[i], response_keys->keys_values[i]);
 849         }
 850
 851         bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
 852         if ((bhslr2->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0 &&
 853             login_nsg(response) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) {
 854                 if (conn->conn_conf.isc_mutual_user[0] != '\0') {
 855                         log_errx(1, "target requested transition "
 856                             "to operational negotiation, but we require "
 857                             "mutual CHAP");
 858                 }
 859
 860                 log_debugx("target requested transition "
 861                     "to operational negotiation");
 862                 keys_delete(response_keys);
 863                 pdu_delete(response);
 864                 login_negotiate(conn);
 865                 return;
 866         }
 867
 868         auth_method = keys_find(response_keys, "AuthMethod");
 869         if (auth_method == NULL)
 870                 log_errx(1, "received response without AuthMethod");
 871         if (strcmp(auth_method, "None") == 0) {
 872                 if (conn->conn_conf.isc_mutual_user[0] != '\0') {
 873                         log_errx(1, "target does not require authantication, "
 874                             "but we require mutual CHAP");
 875                 }
 876
 877                 log_debugx("target does not require authentication");
 878                 keys_delete(response_keys);
 879                 pdu_delete(response);
 880                 login_negotiate(conn);
 881                 return;
 882         }
 883
 884         if (strcmp(auth_method, "CHAP") != 0) {
 885                 fail(conn, "Unsupported AuthMethod");
 886                 log_errx(1, "received response "
 887                     "with unsupported AuthMethod \"%s\"", auth_method);
 888         }
 889
 890         if (conn->conn_conf.isc_user[0] == '\0' ||
 891             conn->conn_conf.isc_secret[0] == '\0') {
 892                 fail(conn, "Authentication required");
 893                 log_errx(1, "target requests CHAP authentication, but we don't "
 894                     "have user and secret");
 895         }
 896
 897         keys_delete(response_keys);
 898         response_keys = NULL;
 899         pdu_delete(response);
 900         response = NULL;
 901
 902         login_chap(conn);
 903         login_negotiate(conn);
 904 }