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 <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
  47 static int
  48 login_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
  57 static void
  58 login_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
  72 static void
  73 login_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
  87 static const char *
  88 login_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
 162 static void
 163 kernel_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  */
 190 static void
 191 login_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
 216 static struct pdu *
 217 login_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
 268 static struct pdu *
 269 login_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
 290 static int
 291 login_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
 312 static int
 313 login_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  */
 362 static int
 363 login_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
 413 static char *
 414 login_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
 435 static void
 436 login_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
 454 static void
 455 login_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
 552 static void
 553 login_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 operational 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("operational parameter negotiation done; "
 623             "transitioning to Full Feature phase");
 624
 625         keys_delete(response_keys);
 626         pdu_delete(response);
 627 }
 628
 629 static void
 630 login_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
 644 static void
 645 login_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
 739 static void
 740 login_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
 786 static void
 787 login_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
 814 void
 815 login(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 parameter negotiation, "
 894                             "but we require mutual CHAP");
 895                 }
 896
 897                 log_debugx("target requested transition "
 898                     "to operational parameter 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 }