usr.sbin/ctld/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 <assert.h>
  33 #include <stdbool.h>
  34 #include <stdint.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <unistd.h>
  39 #include <netinet/in.h>
  40 #include <openssl/err.h>
  41 #include <openssl/md5.h>
  42 #include <openssl/rand.h>
  43
  44 #include "ctld.h"
  45 #include "iscsi_proto.h"
  46
  47 static void login_send_error(struct pdu *request,
  48     char class, char detail);
  49
  50 static void
  51 login_set_nsg(struct pdu *response, int nsg)
  52 {
  53         struct iscsi_bhs_login_response *bhslr;
  54
  55         assert(nsg == BHSLR_STAGE_SECURITY_NEGOTIATION ||
  56             nsg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION ||
  57             nsg == BHSLR_STAGE_FULL_FEATURE_PHASE);
  58
  59         bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs;
  60
  61         bhslr->bhslr_flags &= 0xFC;
  62         bhslr->bhslr_flags |= nsg;
  63 }
  64
  65 static int
  66 login_csg(const struct pdu *request)
  67 {
  68         struct iscsi_bhs_login_request *bhslr;
  69
  70         bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
  71
  72         return ((bhslr->bhslr_flags & 0x0C) >> 2);
  73 }
  74
  75 static void
  76 login_set_csg(struct pdu *response, int csg)
  77 {
  78         struct iscsi_bhs_login_response *bhslr;
  79
  80         assert(csg == BHSLR_STAGE_SECURITY_NEGOTIATION ||
  81             csg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION ||
  82             csg == BHSLR_STAGE_FULL_FEATURE_PHASE);
  83
  84         bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs;
  85
  86         bhslr->bhslr_flags &= 0xF3;
  87         bhslr->bhslr_flags |= csg << 2;
  88 }
  89
  90 static struct pdu *
  91 login_receive(struct connection *conn, bool initial)
  92 {
  93         struct pdu *request;
  94         struct iscsi_bhs_login_request *bhslr;
  95
  96         request = pdu_new(conn);
  97         pdu_receive(request);
  98         if ((request->pdu_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) !=
  99             ISCSI_BHS_OPCODE_LOGIN_REQUEST) {
 100                 /*
 101                  * The first PDU in session is special - if we receive any PDU
 102                  * different than login request, we have to drop the connection
 103                  * without sending response ("A target receiving any PDU
 104                  * except a Login request before the Login Phase is started MUST
 105                  * immediately terminate the connection on which the PDU
 106                  * was received.")
 107                  */
 108                 if (initial == false)
 109                         login_send_error(request, 0x02, 0x0b);
 110                 log_errx(1, "protocol error: received invalid opcode 0x%x",
 111                     request->pdu_bhs->bhs_opcode);
 112         }
 113         bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
 114         /*
 115          * XXX: Implement the C flag some day.
 116          */
 117         if ((bhslr->bhslr_flags & BHSLR_FLAGS_CONTINUE) != 0) {
 118                 login_send_error(request, 0x03, 0x00);
 119                 log_errx(1, "received Login PDU with unsupported \"C\" flag");
 120         }
 121         if (bhslr->bhslr_version_max != 0x00) {
 122                 login_send_error(request, 0x02, 0x05);
 123                 log_errx(1, "received Login PDU with unsupported "
 124                     "Version-max 0x%x", bhslr->bhslr_version_max);
 125         }
 126         if (bhslr->bhslr_version_min != 0x00) {
 127                 login_send_error(request, 0x02, 0x05);
 128                 log_errx(1, "received Login PDU with unsupported "
 129                     "Version-min 0x%x", bhslr->bhslr_version_min);
 130         }
 131         if (ntohl(bhslr->bhslr_cmdsn) < conn->conn_cmdsn) {
 132                 login_send_error(request, 0x02, 0x05);
 133                 log_errx(1, "received Login PDU with decreasing CmdSN: "
 134                     "was %d, is %d", conn->conn_cmdsn,
 135                     ntohl(bhslr->bhslr_cmdsn));
 136         }
 137         if (initial == false &&
 138             ntohl(bhslr->bhslr_expstatsn) != conn->conn_statsn) {
 139                 login_send_error(request, 0x02, 0x05);
 140                 log_errx(1, "received Login PDU with wrong ExpStatSN: "
 141                     "is %d, should be %d", ntohl(bhslr->bhslr_expstatsn),
 142                     conn->conn_statsn);
 143         }
 144         conn->conn_cmdsn = ntohl(bhslr->bhslr_cmdsn);
 145
 146         return (request);
 147 }
 148
 149 static struct pdu *
 150 login_new_response(struct pdu *request)
 151 {
 152         struct pdu *response;
 153         struct connection *conn;
 154         struct iscsi_bhs_login_request *bhslr;
 155         struct iscsi_bhs_login_response *bhslr2;
 156
 157         bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
 158         conn = request->pdu_connection;
 159
 160         response = pdu_new_response(request);
 161         bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
 162         bhslr2->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_RESPONSE;
 163         login_set_csg(response, BHSLR_STAGE_SECURITY_NEGOTIATION);
 164         memcpy(bhslr2->bhslr_isid,
 165             bhslr->bhslr_isid, sizeof(bhslr2->bhslr_isid));
 166         bhslr2->bhslr_initiator_task_tag = bhslr->bhslr_initiator_task_tag;
 167         bhslr2->bhslr_statsn = htonl(conn->conn_statsn++);
 168         bhslr2->bhslr_expcmdsn = htonl(conn->conn_cmdsn);
 169         bhslr2->bhslr_maxcmdsn = htonl(conn->conn_cmdsn);
 170
 171         return (response);
 172 }
 173
 174 static void
 175 login_send_error(struct pdu *request, char class, char detail)
 176 {
 177         struct pdu *response;
 178         struct iscsi_bhs_login_response *bhslr2;
 179
 180         log_debugx("sending Login Response PDU with failure class 0x%x/0x%x; "
 181             "see next line for reason", class, detail);
 182         response = login_new_response(request);
 183         bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
 184         bhslr2->bhslr_status_class = class;
 185         bhslr2->bhslr_status_detail = detail;
 186
 187         pdu_send(response);
 188         pdu_delete(response);
 189 }
 190
 191 static int
 192 login_list_contains(const char *list, const char *what)
 193 {
 194         char *tofree, *str, *token;
 195
 196         tofree = str = checked_strdup(list);
 197
 198         while ((token = strsep(&str, ",")) != NULL) {
 199                 if (strcmp(token, what) == 0) {
 200                         free(tofree);
 201                         return (1);
 202                 }
 203         }
 204         free(tofree);
 205         return (0);
 206 }
 207
 208 static int
 209 login_list_prefers(const char *list,
 210     const char *choice1, const char *choice2)
 211 {
 212         char *tofree, *str, *token;
 213
 214         tofree = str = checked_strdup(list);
 215
 216         while ((token = strsep(&str, ",")) != NULL) {
 217                 if (strcmp(token, choice1) == 0) {
 218                         free(tofree);
 219                         return (1);
 220                 }
 221                 if (strcmp(token, choice2) == 0) {
 222                         free(tofree);
 223                         return (2);
 224                 }
 225         }
 226         free(tofree);
 227         return (-1);
 228 }
 229
 230 static int
 231 login_hex2int(const char hex)
 232 {
 233         switch (hex) {
 234         case '0':
 235                 return (0x00);
 236         case '1':
 237                 return (0x01);
 238         case '2':
 239                 return (0x02);
 240         case '3':
 241                 return (0x03);
 242         case '4':
 243                 return (0x04);
 244         case '5':
 245                 return (0x05);
 246         case '6':
 247                 return (0x06);
 248         case '7':
 249                 return (0x07);
 250         case '8':
 251                 return (0x08);
 252         case '9':
 253                 return (0x09);
 254         case 'a':
 255         case 'A':
 256                 return (0x0a);
 257         case 'b':
 258         case 'B':
 259                 return (0x0b);
 260         case 'c':
 261         case 'C':
 262                 return (0x0c);
 263         case 'd':
 264         case 'D':
 265                 return (0x0d);
 266         case 'e':
 267         case 'E':
 268                 return (0x0e);
 269         case 'f':
 270         case 'F':
 271                 return (0x0f);
 272         default:
 273                 return (-1);
 274         }
 275 }
 276
 277 /*
 278  * XXX: Review this _carefully_.
 279  */
 280 static int
 281 login_hex2bin(const char *hex, char **binp, size_t *bin_lenp)
 282 {
 283         int i, hex_len, nibble;
 284         bool lo = true; /* As opposed to 'hi'. */
 285         char *bin;
 286         size_t bin_off, bin_len;
 287
 288         if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
 289                 log_warnx("malformed variable, should start with \"0x\"");
 290                 return (-1);
 291         }
 292
 293         hex += strlen("0x");
 294         hex_len = strlen(hex);
 295         if (hex_len < 1) {
 296                 log_warnx("malformed variable; doesn't contain anything "
 297                     "but \"0x\"");
 298                 return (-1);
 299         }
 300
 301         bin_len = hex_len / 2 + hex_len % 2;
 302         bin = calloc(bin_len, 1);
 303         if (bin == NULL)
 304                 log_err(1, "calloc");
 305
 306         bin_off = bin_len - 1;
 307         for (i = hex_len - 1; i >= 0; i--) {
 308                 nibble = login_hex2int(hex[i]);
 309                 if (nibble < 0) {
 310                         log_warnx("malformed variable, invalid char \"%c\"",
 311                             hex[i]);
 312                         return (-1);
 313                 }
 314
 315                 assert(bin_off < bin_len);
 316                 if (lo) {
 317                         bin[bin_off] = nibble;
 318                         lo = false;
 319                 } else {
 320                         bin[bin_off] |= nibble << 4;
 321                         bin_off--;
 322                         lo = true;
 323                 }
 324         }
 325
 326         *binp = bin;
 327         *bin_lenp = bin_len;
 328         return (0);
 329 }
 330
 331 static char *
 332 login_bin2hex(const char *bin, size_t bin_len)
 333 {
 334         unsigned char *hex, *tmp, ch;
 335         size_t hex_len;
 336         size_t i;
 337
 338         hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
 339         hex = malloc(hex_len);
 340         if (hex == NULL)
 341                 log_err(1, "malloc");
 342
 343         tmp = hex;
 344         tmp += sprintf(tmp, "0x");
 345         for (i = 0; i < bin_len; i++) {
 346                 ch = bin[i];
 347                 tmp += sprintf(tmp, "%02x", ch);
 348         }
 349
 350         return (hex);
 351 }
 352
 353 static void
 354 login_compute_md5(const char id, const char *secret,
 355     const void *challenge, size_t challenge_len, void *response,
 356     size_t response_len)
 357 {
 358         MD5_CTX ctx;
 359         int rv;
 360
 361         assert(response_len == MD5_DIGEST_LENGTH);
 362
 363         MD5_Init(&ctx);
 364         MD5_Update(&ctx, &id, sizeof(id));
 365         MD5_Update(&ctx, secret, strlen(secret));
 366         MD5_Update(&ctx, challenge, challenge_len);
 367         rv = MD5_Final(response, &ctx);
 368         if (rv != 1)
 369                 log_errx(1, "MD5_Final");
 370 }
 371
 372 #define LOGIN_CHALLENGE_LEN     1024
 373
 374 static struct pdu *
 375 login_receive_chap_a(struct connection *conn)
 376 {
 377         struct pdu *request;
 378         struct keys *request_keys;
 379         const char *chap_a;
 380
 381         request = login_receive(conn, false);
 382         request_keys = keys_new();
 383         keys_load(request_keys, request);
 384
 385         chap_a = keys_find(request_keys, "CHAP_A");
 386         if (chap_a == NULL) {
 387                 login_send_error(request, 0x02, 0x07);
 388                 log_errx(1, "received CHAP Login PDU without CHAP_A");
 389         }
 390         if (login_list_contains(chap_a, "5") == 0) {
 391                 login_send_error(request, 0x02, 0x01);
 392                 log_errx(1, "received CHAP Login PDU with unsupported CHAP_A "
 393                     "\"%s\"", chap_a);
 394         }
 395         keys_delete(request_keys);
 396
 397         return (request);
 398 }
 399
 400 static void
 401 login_send_chap_c(struct pdu *request, const unsigned char id,
 402     const void *challenge, const size_t challenge_len)
 403 {
 404         struct pdu *response;
 405         struct keys *response_keys;
 406         char *chap_c, chap_i[4];
 407
 408         chap_c = login_bin2hex(challenge, challenge_len);
 409         snprintf(chap_i, sizeof(chap_i), "%d", id);
 410
 411         response = login_new_response(request);
 412         response_keys = keys_new();
 413         keys_add(response_keys, "CHAP_A", "5");
 414         keys_add(response_keys, "CHAP_I", chap_i);
 415         keys_add(response_keys, "CHAP_C", chap_c);
 416         free(chap_c);
 417         keys_save(response_keys, response);
 418         pdu_send(response);
 419         pdu_delete(response);
 420         keys_delete(response_keys);
 421 }
 422
 423 static struct pdu *
 424 login_receive_chap_r(struct connection *conn,
 425     struct auth_group *ag, const unsigned char id, const void *challenge,
 426     const size_t challenge_len, const struct auth **cap)
 427 {
 428         struct pdu *request;
 429         struct keys *request_keys;
 430         const char *chap_n, *chap_r;
 431         char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH];
 432         size_t response_bin_len;
 433         const struct auth *auth;
 434         int error;
 435
 436         request = login_receive(conn, false);
 437         request_keys = keys_new();
 438         keys_load(request_keys, request);
 439
 440         chap_n = keys_find(request_keys, "CHAP_N");
 441         if (chap_n == NULL) {
 442                 login_send_error(request, 0x02, 0x07);
 443                 log_errx(1, "received CHAP Login PDU without CHAP_N");
 444         }
 445         chap_r = keys_find(request_keys, "CHAP_R");
 446         if (chap_r == NULL) {
 447                 login_send_error(request, 0x02, 0x07);
 448                 log_errx(1, "received CHAP Login PDU without CHAP_R");
 449         }
 450         error = login_hex2bin(chap_r, &response_bin, &response_bin_len);
 451         if (error != 0) {
 452                 login_send_error(request, 0x02, 0x07);
 453                 log_errx(1, "received CHAP Login PDU with malformed CHAP_R");
 454         }
 455
 456         /*
 457          * Verify the response.
 458          */
 459         assert(ag->ag_type == AG_TYPE_CHAP ||
 460             ag->ag_type == AG_TYPE_CHAP_MUTUAL);
 461         auth = auth_find(ag, chap_n);
 462         if (auth == NULL) {
 463                 login_send_error(request, 0x02, 0x01);
 464                 log_errx(1, "received CHAP Login with invalid user \"%s\"",
 465                     chap_n);
 466         }
 467
 468         assert(auth->a_secret != NULL);
 469         assert(strlen(auth->a_secret) > 0);
 470         login_compute_md5(id, auth->a_secret, challenge,
 471             challenge_len, expected_response_bin,
 472             sizeof(expected_response_bin));
 473
 474         if (memcmp(response_bin, expected_response_bin,
 475             sizeof(expected_response_bin)) != 0) {
 476                 login_send_error(request, 0x02, 0x01);
 477                 log_errx(1, "CHAP authentication failed for user \"%s\"",
 478                     auth->a_user);
 479         }
 480
 481         keys_delete(request_keys);
 482         free(response_bin);
 483
 484         *cap = auth;
 485         return (request);
 486 }
 487
 488 static void
 489 login_send_chap_success(struct pdu *request,
 490     const struct auth *auth)
 491 {
 492         struct pdu *response;
 493         struct keys *request_keys, *response_keys;
 494         struct iscsi_bhs_login_response *bhslr2;
 495         const char *chap_i, *chap_c;
 496         char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH];
 497         size_t challenge_len;
 498         unsigned char id;
 499         int error;
 500
 501         response = login_new_response(request);
 502         bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
 503         bhslr2->bhslr_flags |= BHSLR_FLAGS_TRANSIT;
 504         login_set_nsg(response, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
 505
 506         /*
 507          * Actually, one more thing: mutual authentication.
 508          */
 509         request_keys = keys_new();
 510         keys_load(request_keys, request);
 511         chap_i = keys_find(request_keys, "CHAP_I");
 512         chap_c = keys_find(request_keys, "CHAP_C");
 513         if (chap_i != NULL || chap_c != NULL) {
 514                 if (chap_i == NULL) {
 515                         login_send_error(request, 0x02, 0x07);
 516                         log_errx(1, "initiator requested target "
 517                             "authentication, but didn't send CHAP_I");
 518                 }
 519                 if (chap_c == NULL) {
 520                         login_send_error(request, 0x02, 0x07);
 521                         log_errx(1, "initiator requested target "
 522                             "authentication, but didn't send CHAP_C");
 523                 }
 524                 if (auth->a_auth_group->ag_type != AG_TYPE_CHAP_MUTUAL) {
 525                         login_send_error(request, 0x02, 0x01);
 526                         log_errx(1, "initiator requests target authentication "
 527                             "for user \"%s\", but mutual user/secret "
 528                             "is not set", auth->a_user);
 529                 }
 530
 531                 id = strtoul(chap_i, NULL, 10);
 532                 error = login_hex2bin(chap_c, &challenge, &challenge_len);
 533                 if (error != 0) {
 534                         login_send_error(request, 0x02, 0x07);
 535                         log_errx(1, "received CHAP Login PDU with malformed "
 536                             "CHAP_C");
 537                 }
 538
 539                 log_debugx("performing mutual authentication as user \"%s\"",
 540                     auth->a_mutual_user);
 541                 login_compute_md5(id, auth->a_mutual_secret, challenge,
 542                     challenge_len, response_bin, sizeof(response_bin));
 543
 544                 chap_r = login_bin2hex(response_bin,
 545                     sizeof(response_bin));
 546                 response_keys = keys_new();
 547                 keys_add(response_keys, "CHAP_N", auth->a_mutual_user);
 548                 keys_add(response_keys, "CHAP_R", chap_r);
 549                 free(chap_r);
 550                 keys_save(response_keys, response);
 551                 keys_delete(response_keys);
 552         } else {
 553                 log_debugx("initiator did not request target authentication");
 554         }
 555
 556         keys_delete(request_keys);
 557         pdu_send(response);
 558         pdu_delete(response);
 559 }
 560
 561 static void
 562 login_chap(struct connection *conn, struct auth_group *ag)
 563 {
 564         const struct auth *auth;
 565         struct pdu *request;
 566         char challenge_bin[LOGIN_CHALLENGE_LEN];
 567         unsigned char id;
 568         int rv;
 569
 570         /*
 571          * Receive CHAP_A PDU.
 572          */
 573         log_debugx("beginning CHAP authentication; waiting for CHAP_A");
 574         request = login_receive_chap_a(conn);
 575
 576         /*
 577          * Generate the challenge.
 578          */
 579         rv = RAND_bytes(challenge_bin, sizeof(challenge_bin));
 580         if (rv != 1) {
 581                 login_send_error(request, 0x03, 0x02);
 582                 log_errx(1, "RAND_bytes failed: %s",
 583                     ERR_error_string(ERR_get_error(), NULL));
 584         }
 585         rv = RAND_bytes(&id, sizeof(id));
 586         if (rv != 1) {
 587                 login_send_error(request, 0x03, 0x02);
 588                 log_errx(1, "RAND_bytes failed: %s",
 589                     ERR_error_string(ERR_get_error(), NULL));
 590         }
 591
 592         /*
 593          * Send the challenge.
 594          */
 595         log_debugx("sending CHAP_C, binary challenge size is %zd bytes",
 596             sizeof(challenge_bin));
 597         login_send_chap_c(request, id, challenge_bin,
 598             sizeof(challenge_bin));
 599         pdu_delete(request);
 600
 601         /*
 602          * Receive CHAP_N/CHAP_R PDU and authenticate.
 603          */
 604         log_debugx("waiting for CHAP_N/CHAP_R");
 605         request = login_receive_chap_r(conn, ag, id, challenge_bin,
 606             sizeof(challenge_bin), &auth);
 607
 608         /*
 609          * Yay, authentication succeeded!
 610          */
 611         log_debugx("authentication succeeded for user \"%s\"; "
 612             "transitioning to Negotiation Phase", auth->a_user);
 613         login_send_chap_success(request, auth);
 614         pdu_delete(request);
 615 }
 616
 617 static void
 618 login_negotiate_key(struct pdu *request, const char *name,
 619     const char *value, bool skipped_security, struct keys *response_keys)
 620 {
 621         int which, tmp;
 622         struct connection *conn;
 623
 624         conn = request->pdu_connection;
 625
 626         if (strcmp(name, "InitiatorName") == 0) {
 627                 if (!skipped_security)
 628                         log_errx(1, "initiator resent InitiatorName");
 629         } else if (strcmp(name, "SessionType") == 0) {
 630                 if (!skipped_security)
 631                         log_errx(1, "initiator resent SessionType");
 632         } else if (strcmp(name, "TargetName") == 0) {
 633                 if (!skipped_security)
 634                         log_errx(1, "initiator resent TargetName");
 635         } else if (strcmp(name, "InitiatorAlias") == 0) {
 636                 if (conn->conn_initiator_alias != NULL)
 637                         free(conn->conn_initiator_alias);
 638                 conn->conn_initiator_alias = checked_strdup(value);
 639         } else if (strcmp(value, "Irrelevant") == 0) {
 640                 /* Ignore. */
 641         } else if (strcmp(name, "HeaderDigest") == 0) {
 642                 /*
 643                  * We don't handle digests for discovery sessions.
 644                  */
 645                 if (conn->conn_session_type == CONN_SESSION_TYPE_DISCOVERY) {
 646                         log_debugx("discovery session; digests disabled");
 647                         keys_add(response_keys, name, "None");
 648                         return;
 649                 }
 650
 651                 which = login_list_prefers(value, "CRC32C", "None");
 652                 switch (which) {
 653                 case 1:
 654                         log_debugx("initiator prefers CRC32C "
 655                             "for header digest; we'll use it");
 656                         conn->conn_header_digest = CONN_DIGEST_CRC32C;
 657                         keys_add(response_keys, name, "CRC32C");
 658                         break;
 659                 case 2:
 660                         log_debugx("initiator prefers not to do "
 661                             "header digest; we'll comply");
 662                         keys_add(response_keys, name, "None");
 663                         break;
 664                 default:
 665                         log_warnx("initiator sent unrecognized "
 666                             "HeaderDigest value \"%s\"; will use None", value);
 667                         keys_add(response_keys, name, "None");
 668                         break;
 669                 }
 670         } else if (strcmp(name, "DataDigest") == 0) {
 671                 if (conn->conn_session_type == CONN_SESSION_TYPE_DISCOVERY) {
 672                         log_debugx("discovery session; digests disabled");
 673                         keys_add(response_keys, name, "None");
 674                         return;
 675                 }
 676
 677                 which = login_list_prefers(value, "CRC32C", "None");
 678                 switch (which) {
 679                 case 1:
 680                         log_debugx("initiator prefers CRC32C "
 681                             "for data digest; we'll use it");
 682                         conn->conn_data_digest = CONN_DIGEST_CRC32C;
 683                         keys_add(response_keys, name, "CRC32C");
 684                         break;
 685                 case 2:
 686                         log_debugx("initiator prefers not to do "
 687                             "data digest; we'll comply");
 688                         keys_add(response_keys, name, "None");
 689                         break;
 690                 default:
 691                         log_warnx("initiator sent unrecognized "
 692                             "DataDigest value \"%s\"; will use None", value);
 693                         keys_add(response_keys, name, "None");
 694                         break;
 695                 }
 696         } else if (strcmp(name, "MaxConnections") == 0) {
 697                 keys_add(response_keys, name, "1");
 698         } else if (strcmp(name, "InitialR2T") == 0) {
 699                 keys_add(response_keys, name, "Yes");
 700         } else if (strcmp(name, "ImmediateData") == 0) {
 701                 if (conn->conn_session_type == CONN_SESSION_TYPE_DISCOVERY) {
 702                         log_debugx("discovery session; ImmediateData irrelevant");
 703                         keys_add(response_keys, name, "Irrelevant");
 704                 } else {
 705                         if (strcmp(value, "Yes") == 0) {
 706                                 conn->conn_immediate_data = true;
 707                                 keys_add(response_keys, name, "Yes");
 708                         } else {
 709                                 conn->conn_immediate_data = false;
 710                                 keys_add(response_keys, name, "No");
 711                         }
 712                 }
 713         } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) {
 714                 tmp = strtoul(value, NULL, 10);
 715                 if (tmp <= 0) {
 716                         login_send_error(request, 0x02, 0x00);
 717                         log_errx(1, "received invalid "
 718                             "MaxRecvDataSegmentLength");
 719                 }
 720                 if (tmp > MAX_DATA_SEGMENT_LENGTH) {
 721                         log_debugx("capping MaxDataSegmentLength from %d to %d",
 722                             tmp, MAX_DATA_SEGMENT_LENGTH);
 723                         tmp = MAX_DATA_SEGMENT_LENGTH;
 724                 }
 725                 conn->conn_max_data_segment_length = tmp;
 726                 keys_add_int(response_keys, name, tmp);
 727         } else if (strcmp(name, "MaxBurstLength") == 0) {
 728                 tmp = strtoul(value, NULL, 10);
 729                 if (tmp <= 0) {
 730                         login_send_error(request, 0x02, 0x00);
 731                         log_errx(1, "received invalid MaxBurstLength");
 732                 }
 733                 if (tmp > MAX_BURST_LENGTH) {
 734                         log_debugx("capping MaxBurstLength from %d to %d",
 735                             tmp, MAX_BURST_LENGTH);
 736                         tmp = MAX_BURST_LENGTH;
 737                 }
 738                 conn->conn_max_burst_length = tmp;
 739                 keys_add(response_keys, name, value);
 740         } else if (strcmp(name, "FirstBurstLength") == 0) {
 741                 tmp = strtoul(value, NULL, 10);
 742                 if (tmp <= 0) {
 743                         login_send_error(request, 0x02, 0x00);
 744                         log_errx(1, "received invalid "
 745                             "FirstBurstLength");
 746                 }
 747                 if (tmp > MAX_DATA_SEGMENT_LENGTH) {
 748                         log_debugx("capping FirstBurstLength from %d to %d",
 749                             tmp, MAX_DATA_SEGMENT_LENGTH);
 750                         tmp = MAX_DATA_SEGMENT_LENGTH;
 751                 }
 752                 /*
 753                  * We don't pass the value to the kernel; it only enforces
 754                  * hardcoded limit anyway.
 755                  */
 756                 keys_add_int(response_keys, name, tmp);
 757         } else if (strcmp(name, "DefaultTime2Wait") == 0) {
 758                 keys_add(response_keys, name, value);
 759         } else if (strcmp(name, "DefaultTime2Retain") == 0) {
 760                 keys_add(response_keys, name, "0");
 761         } else if (strcmp(name, "MaxOutstandingR2T") == 0) {
 762                 keys_add(response_keys, name, "1");
 763         } else if (strcmp(name, "DataPDUInOrder") == 0) {
 764                 keys_add(response_keys, name, "Yes");
 765         } else if (strcmp(name, "DataSequenceInOrder") == 0) {
 766                 keys_add(response_keys, name, "Yes");
 767         } else if (strcmp(name, "ErrorRecoveryLevel") == 0) {
 768                 keys_add(response_keys, name, "0");
 769         } else if (strcmp(name, "OFMarker") == 0) {
 770                 keys_add(response_keys, name, "No");
 771         } else if (strcmp(name, "IFMarker") == 0) {
 772                 keys_add(response_keys, name, "No");
 773         } else {
 774                 log_debugx("unknown key \"%s\"; responding "
 775                     "with NotUnderstood", name);
 776                 keys_add(response_keys, name, "NotUnderstood");
 777         }
 778 }
 779
 780 static void
 781 login_negotiate(struct connection *conn, struct pdu *request)
 782 {
 783         struct pdu *response;
 784         struct iscsi_bhs_login_response *bhslr2;
 785         struct keys *request_keys, *response_keys;
 786         int i;
 787         bool skipped_security;
 788
 789         if (request == NULL) {
 790                 log_debugx("beginning operational parameter negotiation; "
 791                     "waiting for Login PDU");
 792                 request = login_receive(conn, false);
 793                 skipped_security = false;
 794         } else
 795                 skipped_security = true;
 796
 797         request_keys = keys_new();
 798         keys_load(request_keys, request);
 799
 800         response = login_new_response(request);
 801         bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
 802         bhslr2->bhslr_flags |= BHSLR_FLAGS_TRANSIT;
 803         bhslr2->bhslr_tsih = htons(0xbadd);
 804         login_set_csg(response, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
 805         login_set_nsg(response, BHSLR_STAGE_FULL_FEATURE_PHASE);
 806         response_keys = keys_new();
 807         for (i = 0; i < KEYS_MAX; i++) {
 808                 if (request_keys->keys_names[i] == NULL)
 809                         break;
 810
 811                 login_negotiate_key(request, request_keys->keys_names[i],
 812                     request_keys->keys_values[i], skipped_security,
 813                     response_keys);
 814         }
 815
 816         log_debugx("operational parameter negotiation done; "
 817             "transitioning to Full Feature Phase");
 818
 819         keys_save(response_keys, response);
 820         pdu_send(response);
 821         pdu_delete(response);
 822         keys_delete(response_keys);
 823         pdu_delete(request);
 824         keys_delete(request_keys);
 825 }
 826
 827 void
 828 login(struct connection *conn)
 829 {
 830         struct pdu *request, *response;
 831         struct iscsi_bhs_login_request *bhslr;
 832         struct iscsi_bhs_login_response *bhslr2;
 833         struct keys *request_keys, *response_keys;
 834         struct auth_group *ag;
 835         const char *initiator_name, *initiator_alias, *session_type,
 836             *target_name, *auth_method;
 837         char *portal_group_tag;
 838         int rv;
 839
 840         /*
 841          * Handle the initial Login Request - figure out required authentication
 842          * method and either transition to the next phase, if no authentication
 843          * is required, or call appropriate authentication code.
 844          */
 845         log_debugx("beginning Login Phase; waiting for Login PDU");
 846         request = login_receive(conn, true);
 847         bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
 848         if (bhslr->bhslr_tsih != 0) {
 849                 login_send_error(request, 0x02, 0x0a);
 850                 log_errx(1, "received Login PDU with non-zero TSIH");
 851         }
 852
 853         /*
 854          * XXX: Implement the C flag some day.
 855          */
 856         request_keys = keys_new();
 857         keys_load(request_keys, request);
 858
 859         assert(conn->conn_initiator_name == NULL);
 860         initiator_name = keys_find(request_keys, "InitiatorName");
 861         if (initiator_name == NULL) {
 862                 login_send_error(request, 0x02, 0x07);
 863                 log_errx(1, "received Login PDU without InitiatorName");
 864         }
 865         if (valid_iscsi_name(initiator_name) == false) {
 866                 login_send_error(request, 0x02, 0x00);
 867                 log_errx(1, "received Login PDU with invalid InitiatorName");
 868         }
 869         conn->conn_initiator_name = checked_strdup(initiator_name);
 870         log_set_peer_name(conn->conn_initiator_name);
 871         /*
 872          * XXX: This doesn't work (does nothing) because of Capsicum.
 873          */
 874         setproctitle("%s (%s)", conn->conn_initiator_addr, conn->conn_initiator_name);
 875
 876         initiator_alias = keys_find(request_keys, "InitiatorAlias");
 877         if (initiator_alias != NULL)
 878                 conn->conn_initiator_alias = checked_strdup(initiator_alias);
 879
 880         assert(conn->conn_session_type == CONN_SESSION_TYPE_NONE);
 881         session_type = keys_find(request_keys, "SessionType");
 882         if (session_type != NULL) {
 883                 if (strcmp(session_type, "Normal") == 0) {
 884                         conn->conn_session_type = CONN_SESSION_TYPE_NORMAL;
 885                 } else if (strcmp(session_type, "Discovery") == 0) {
 886                         conn->conn_session_type = CONN_SESSION_TYPE_DISCOVERY;
 887                 } else {
 888                         login_send_error(request, 0x02, 0x00);
 889                         log_errx(1, "received Login PDU with invalid "
 890                             "SessionType \"%s\"", session_type);
 891                 }
 892         } else
 893                 conn->conn_session_type = CONN_SESSION_TYPE_NORMAL;
 894
 895         assert(conn->conn_target == NULL);
 896         if (conn->conn_session_type == CONN_SESSION_TYPE_NORMAL) {
 897                 target_name = keys_find(request_keys, "TargetName");
 898                 if (target_name == NULL) {
 899                         login_send_error(request, 0x02, 0x07);
 900                         log_errx(1, "received Login PDU without TargetName");
 901                 }
 902
 903                 conn->conn_target =
 904                     target_find(conn->conn_portal->p_portal_group->pg_conf,
 905                     target_name);
 906                 if (conn->conn_target == NULL) {
 907                         login_send_error(request, 0x02, 0x03);
 908                         log_errx(1, "requested target \"%s\" not found",
 909                             target_name);
 910                 }
 911         }
 912
 913         /*
 914          * At this point we know what kind of authentication we need.
 915          */
 916         if (conn->conn_session_type == CONN_SESSION_TYPE_NORMAL) {
 917                 ag = conn->conn_target->t_auth_group;
 918                 if (ag->ag_name != NULL) {
 919                         log_debugx("initiator requests to connect "
 920                             "to target \"%s\"; auth-group \"%s\"",
 921                             conn->conn_target->t_name,
 922                             conn->conn_target->t_auth_group->ag_name);
 923                 } else {
 924                         log_debugx("initiator requests to connect "
 925                             "to target \"%s\"", conn->conn_target->t_name);
 926                 }
 927         } else {
 928                 assert(conn->conn_session_type == CONN_SESSION_TYPE_DISCOVERY);
 929                 ag = conn->conn_portal->p_portal_group->pg_discovery_auth_group;
 930                 if (ag->ag_name != NULL) {
 931                         log_debugx("initiator requests "
 932                             "discovery session; auth-group \"%s\"", ag->ag_name);
 933                 } else {
 934                         log_debugx("initiator requests discovery session");
 935                 }
 936         }
 937
 938         /*
 939          * Enforce initiator-name and initiator-portal.
 940          */
 941         if (auth_name_defined(ag)) {
 942                 if (auth_name_find(ag, initiator_name) == NULL) {
 943                         login_send_error(request, 0x02, 0x02);
 944                         log_errx(1, "initiator does not match allowed "
 945                             "initiator names");
 946                 }
 947                 log_debugx("initiator matches allowed initiator names");
 948         } else {
 949                 log_debugx("auth-group does not define initiator name "
 950                     "restrictions");
 951         }
 952
 953         if (auth_portal_defined(ag)) {
 954                 if (auth_portal_find(ag, conn->conn_initiator_addr) == NULL) {
 955                         login_send_error(request, 0x02, 0x02);
 956                         log_errx(1, "initiator does not match allowed "
 957                             "initiator portals");
 958                 }
 959                 log_debugx("initiator matches allowed initiator portals");
 960         } else {
 961                 log_debugx("auth-group does not define initiator portal "
 962                     "restrictions");
 963         }
 964
 965         /*
 966          * Let's see if the initiator intends to do any kind of authentication
 967          * at all.
 968          */
 969         if (login_csg(request) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) {
 970                 if (ag->ag_type != AG_TYPE_NO_AUTHENTICATION) {
 971                         login_send_error(request, 0x02, 0x01);
 972                         log_errx(1, "initiator skipped the authentication, "
 973                             "but authentication is required");
 974                 }
 975
 976                 keys_delete(request_keys);
 977
 978                 log_debugx("initiator skipped the authentication, "
 979                     "and we don't need it; proceeding with negotiation");
 980                 login_negotiate(conn, request);
 981                 return;
 982         }
 983
 984         if (ag->ag_type == AG_TYPE_NO_AUTHENTICATION) {
 985                 /*
 986                  * Initiator might want to to authenticate,
 987                  * but we don't need it.
 988                  */
 989                 log_debugx("authentication not required; "
 990                     "transitioning to operational parameter negotiation");
 991
 992                 if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0)
 993                         log_warnx("initiator did not set the \"T\" flag; "
 994                             "transitioning anyway");
 995
 996                 response = login_new_response(request);
 997                 bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
 998                 bhslr2->bhslr_flags |= BHSLR_FLAGS_TRANSIT;
 999                 login_set_nsg(response,
1000                     BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
1001                 response_keys = keys_new();
1002                 /*
1003                  * Required by Linux initiator.
1004                  */
1005                 auth_method = keys_find(request_keys, "AuthMethod");
1006                 if (auth_method != NULL &&
1007                     login_list_contains(auth_method, "None"))
1008                         keys_add(response_keys, "AuthMethod", "None");
1009
1010                 if (conn->conn_session_type == CONN_SESSION_TYPE_NORMAL) {
1011                         if (conn->conn_target->t_alias != NULL)
1012                                 keys_add(response_keys,
1013                                     "TargetAlias", conn->conn_target->t_alias);
1014                         rv = asprintf(&portal_group_tag, "%d",
1015                             conn->conn_portal->p_portal_group->pg_tag);
1016                         if (rv <= 0)
1017                                 log_err(1, "asprintf");
1018                         keys_add(response_keys,
1019                             "TargetPortalGroupTag", portal_group_tag);
1020                         free(portal_group_tag);
1021                 }
1022                 keys_save(response_keys, response);
1023                 pdu_send(response);
1024                 pdu_delete(response);
1025                 keys_delete(response_keys);
1026                 pdu_delete(request);
1027                 keys_delete(request_keys);
1028
1029                 login_negotiate(conn, NULL);
1030                 return;
1031         }
1032
1033         if (ag->ag_type == AG_TYPE_DENY) {
1034                 login_send_error(request, 0x02, 0x01);
1035                 log_errx(1, "auth-type is \"deny\"");
1036         }
1037
1038         if (ag->ag_type == AG_TYPE_UNKNOWN) {
1039                 /*
1040                  * This can happen with empty auth-group.
1041                  */
1042                 login_send_error(request, 0x02, 0x01);
1043                 log_errx(1, "auth-type not set, denying access");
1044         }
1045
1046         log_debugx("CHAP authentication required");
1047
1048         auth_method = keys_find(request_keys, "AuthMethod");
1049         if (auth_method == NULL) {
1050                 login_send_error(request, 0x02, 0x07);
1051                 log_errx(1, "received Login PDU without AuthMethod");
1052         }
1053         /*
1054          * XXX: This should be Reject, not just a login failure (5.3.2).
1055          */
1056         if (login_list_contains(auth_method, "CHAP") == 0) {
1057                 login_send_error(request, 0x02, 0x01);
1058                 log_errx(1, "initiator requests unsupported AuthMethod \"%s\" "
1059                     "instead of \"CHAP\"", auth_method);
1060         }
1061
1062         response = login_new_response(request);
1063
1064         response_keys = keys_new();
1065         keys_add(response_keys, "AuthMethod", "CHAP");
1066         if (conn->conn_session_type == CONN_SESSION_TYPE_NORMAL) {
1067                 rv = asprintf(&portal_group_tag, "%d",
1068                     conn->conn_portal->p_portal_group->pg_tag);
1069                 if (rv <= 0)
1070                         log_err(1, "asprintf");
1071                 keys_add(response_keys,
1072                     "TargetPortalGroupTag", portal_group_tag);
1073                 free(portal_group_tag);
1074                 if (conn->conn_target->t_alias != NULL)
1075                         keys_add(response_keys,
1076                             "TargetAlias", conn->conn_target->t_alias);
1077         }
1078         keys_save(response_keys, response);
1079
1080         pdu_send(response);
1081         pdu_delete(response);
1082         keys_delete(response_keys);
1083         pdu_delete(request);
1084         keys_delete(request_keys);
1085
1086         login_chap(conn, ag);
1087
1088         login_negotiate(conn, NULL);
1089 }