appl/rsh/rshd.c

   1 /*
   2  * Copyright (c) 1997-2007 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  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  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "rsh_locl.h"
  35 #include "login_locl.h"
  36 RCSID("$Id$");
  37
  38 int
  39 login_access( struct passwd *user, char *from);
  40 int
  41 read_limits_conf(const char *file, const struct passwd *pwd);
  42
  43 #ifdef NEED_IRUSEROK_PROTO
  44 int iruserok(uint32_t, int, const char *, const char *);
  45 #endif
  46
  47 enum auth_method auth_method;
  48
  49 #ifdef KRB5
  50 krb5_context context;
  51 krb5_keyblock *keyblock;
  52 krb5_crypto crypto;
  53 #endif
  54
  55 #ifdef KRB5
  56 krb5_ccache ccache, ccache2;
  57 int kerberos_status = 0;
  58 #endif
  59
  60 int do_encrypt = 0;
  61
  62 static int do_unique_tkfile           = 0;
  63 static char tkfile[MAXPATHLEN] = "";
  64
  65 static int do_inetd = 1;
  66 static char *port_str;
  67 static int do_rhosts = 1;
  68 static int do_kerberos = 0;
  69 #define DO_KRB5 4
  70 static int do_vacuous = 0;
  71 static int do_log = 1;
  72 static int do_newpag = 1;
  73 static int do_addr_verify = 0;
  74 static int do_keepalive = 1;
  75 static int do_version;
  76 static int do_help = 0;
  77
  78 static void
  79 syslog_and_die (const char *m, ...)
  80     __attribute__ ((format (printf, 1, 2)));
  81
  82 static void
  83 syslog_and_die (const char *m, ...)
  84 {
  85     va_list args;
  86
  87     va_start(args, m);
  88     vsyslog (LOG_ERR, m, args);
  89     va_end(args);
  90     exit (1);
  91 }
  92
  93 static void
  94 fatal (int, const char*, const char *, ...)
  95     __attribute__ ((noreturn, format (printf, 3, 4)));
  96
  97 static void
  98 fatal (int sock, const char *what, const char *m, ...)
  99 {
 100     va_list args;
 101     char buf[BUFSIZ];
 102     size_t len;
 103
 104     *buf = 1;
 105     va_start(args, m);
 106     len = vsnprintf (buf + 1, sizeof(buf) - 1, m, args);
 107     len = min(len, sizeof(buf) - 1);
 108     va_end(args);
 109     if(what != NULL)
 110         syslog (LOG_ERR, "%s: %s: %s", what, strerror(errno), buf + 1);
 111     else
 112         syslog (LOG_ERR, "%s", buf + 1);
 113     net_write (sock, buf, len + 1);
 114     exit (1);
 115 }
 116
 117 static char *
 118 read_str (int s, size_t sz, char *expl)
 119 {
 120     char *str = malloc(sz);
 121     char *p = str;
 122     if(str == NULL)
 123         fatal(s, NULL, "%s too long", expl);
 124     while(p < str + sz) {
 125         if(net_read(s, p, 1) != 1)
 126             syslog_and_die("read: %s", strerror(errno));
 127         if(*p == '\0')
 128             return str;
 129         p++;
 130     }
 131     fatal(s, NULL, "%s too long", expl);
 132 }
 133
 134 static int
 135 recv_bsd_auth (int s, u_char *buf,
 136                struct sockaddr_in *thisaddr,
 137                struct sockaddr_in *thataddr,
 138                char **client_username,
 139                char **server_username,
 140                char **cmd)
 141 {
 142     struct passwd *pwd;
 143
 144     *client_username = read_str (s, USERNAME_SZ, "local username");
 145     *server_username = read_str (s, USERNAME_SZ, "remote username");
 146     *cmd = read_str (s, ARG_MAX + 1, "command");
 147     pwd = getpwnam(*server_username);
 148     if (pwd == NULL)
 149         fatal(s, NULL, "Login incorrect.");
 150     if (iruserok(thataddr->sin_addr.s_addr, pwd->pw_uid == 0,
 151                  *client_username, *server_username))
 152         fatal(s, NULL, "Login incorrect.");
 153     return 0;
 154 }
 155
 156 #ifdef KRB5
 157 static int
 158 save_krb5_creds (int s,
 159                  krb5_auth_context auth_context,
 160                  krb5_principal client)
 161
 162 {
 163     int ret;
 164     krb5_data remote_cred;
 165
 166     krb5_data_zero (&remote_cred);
 167     ret= krb5_read_message (context, (void *)&s, &remote_cred);
 168     if (ret) {
 169         krb5_data_free(&remote_cred);
 170         return 0;
 171     }
 172     if (remote_cred.length == 0)
 173         return 0;
 174
 175     ret = krb5_cc_new_unique(context, krb5_cc_type_memory, NULL, &ccache);
 176     if (ret) {
 177         krb5_data_free(&remote_cred);
 178         return 0;
 179     }
 180
 181     krb5_cc_initialize(context,ccache,client);
 182     ret = krb5_rd_cred2(context, auth_context, ccache, &remote_cred);
 183     if(ret != 0)
 184         syslog(LOG_INFO|LOG_AUTH,
 185                "reading creds: %s", krb5_get_err_text(context, ret));
 186     krb5_data_free (&remote_cred);
 187     if (ret)
 188         return 0;
 189     return 1;
 190 }
 191
 192 static void
 193 krb5_start_session (void)
 194 {
 195     krb5_error_code ret;
 196     char *estr;
 197
 198     ret = krb5_cc_resolve (context, tkfile, &ccache2);
 199     if (ret) {
 200         estr = krb5_get_error_string(context);
 201         syslog(LOG_WARNING, "resolve cred cache %s: %s",
 202                tkfile,
 203                estr ? estr : krb5_get_err_text(context, ret));
 204         free(estr);
 205         krb5_cc_destroy(context, ccache);
 206         return;
 207     }
 208
 209     ret = krb5_cc_copy_cache (context, ccache, ccache2);
 210     if (ret) {
 211         estr = krb5_get_error_string(context);
 212         syslog(LOG_WARNING, "storing credentials: %s",
 213                estr ? estr : krb5_get_err_text(context, ret));
 214         free(estr);
 215         krb5_cc_destroy(context, ccache);
 216         return ;
 217     }
 218
 219     krb5_cc_close(context, ccache2);
 220     krb5_cc_destroy(context, ccache);
 221     return;
 222 }
 223
 224 static int protocol_version;
 225
 226 static krb5_boolean
 227 match_kcmd_version(const void *data, const char *version)
 228 {
 229     if(strcmp(version, KCMD_NEW_VERSION) == 0) {
 230         protocol_version = 2;
 231         return TRUE;
 232     }
 233     if(strcmp(version, KCMD_OLD_VERSION) == 0) {
 234         protocol_version = 1;
 235         key_usage = KRB5_KU_OTHER_ENCRYPTED;
 236         return TRUE;
 237     }
 238     return FALSE;
 239 }
 240
 241
 242 static int
 243 recv_krb5_auth (int s, u_char *buf,
 244                 struct sockaddr *thisaddr,
 245                 struct sockaddr *thataddr,
 246                 char **client_username,
 247                 char **server_username,
 248                 char **cmd)
 249 {
 250     uint32_t len;
 251     krb5_auth_context auth_context = NULL;
 252     krb5_ticket *ticket;
 253     krb5_error_code status;
 254     krb5_data cksum_data;
 255     krb5_principal server;
 256     char *str;
 257
 258     if (memcmp (buf, "\x00\x00\x00\x13", 4) != 0)
 259         return -1;
 260     len = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | (buf[3]);
 261
 262     if (net_read(s, buf, len) != len)
 263         syslog_and_die ("reading auth info: %s", strerror(errno));
 264     if (len != sizeof(KRB5_SENDAUTH_VERSION)
 265         || memcmp (buf, KRB5_SENDAUTH_VERSION, len) != 0)
 266         syslog_and_die ("bad sendauth version: %.8s", buf);
 267
 268     status = krb5_sock_to_principal (context,
 269                                      s,
 270                                      "host",
 271                                      KRB5_NT_SRV_HST,
 272                                      &server);
 273     if (status)
 274         syslog_and_die ("krb5_sock_to_principal: %s",
 275                         krb5_get_err_text(context, status));
 276
 277     status = krb5_recvauth_match_version(context,
 278                                          &auth_context,
 279                                          &s,
 280                                          match_kcmd_version,
 281                                          NULL,
 282                                          server,
 283                                          KRB5_RECVAUTH_IGNORE_VERSION,
 284                                          NULL,
 285                                          &ticket);
 286     krb5_free_principal (context, server);
 287     if (status)
 288         syslog_and_die ("krb5_recvauth: %s",
 289                         krb5_get_err_text(context, status));
 290
 291     *server_username = read_str (s, USERNAME_SZ, "remote username");
 292     *cmd = read_str (s, ARG_MAX + 1, "command");
 293     *client_username = read_str (s, ARG_MAX + 1, "local username");
 294
 295     if(protocol_version == 2) {
 296         status = krb5_auth_con_getremotesubkey(context, auth_context,
 297                                                &keyblock);
 298         if(status != 0 || keyblock == NULL)
 299             syslog_and_die("failed to get remote subkey");
 300     } else if(protocol_version == 1) {
 301         status = krb5_auth_con_getkey (context, auth_context, &keyblock);
 302         if(status != 0 || keyblock == NULL)
 303             syslog_and_die("failed to get key");
 304     }
 305     if (status != 0 || keyblock == NULL)
 306        syslog_and_die ("krb5_auth_con_getkey: %s",
 307                        krb5_get_err_text(context, status));
 308
 309     status = krb5_crypto_init(context, keyblock, 0, &crypto);
 310     if(status)
 311         syslog_and_die("krb5_crypto_init: %s",
 312                        krb5_get_err_text(context, status));
 313
 314
 315     cksum_data.length = asprintf (&str,
 316                                   "%u:%s%s",
 317                                   ntohs(socket_get_port (thisaddr)),
 318                                   *cmd,
 319                                   *server_username);
 320     if (str == NULL)
 321         syslog_and_die ("asprintf: out of memory");
 322     cksum_data.data = str;
 323
 324     status = krb5_verify_authenticator_checksum(context,
 325                                                 auth_context,
 326                                                 cksum_data.data,
 327                                                 cksum_data.length);
 328
 329     if (status)
 330         syslog_and_die ("krb5_verify_authenticator_checksum: %s",
 331                         krb5_get_err_text(context, status));
 332
 333     free (cksum_data.data);
 334
 335     if (strncmp (*client_username, "-u ", 3) == 0) {
 336         do_unique_tkfile = 1;
 337         memmove (*client_username, *client_username + 3,
 338                  strlen(*client_username) - 2);
 339     }
 340
 341     if (strncmp (*client_username, "-U ", 3) == 0) {
 342         char *end, *temp_tkfile;
 343
 344         do_unique_tkfile = 1;
 345         if (strncmp (*client_username + 3, "FILE:", 5) == 0) {
 346             temp_tkfile = tkfile;
 347         } else {
 348             strlcpy (tkfile, "FILE:", sizeof(tkfile));
 349             temp_tkfile = tkfile + 5;
 350         }
 351         end = strchr(*client_username + 3,' ');
 352         if (end == NULL)
 353             syslog_and_die("missing argument after -U");
 354         snprintf(temp_tkfile, sizeof(tkfile) - (temp_tkfile - tkfile),
 355                  "%.*s",
 356                  (int)(end - *client_username - 3),
 357                  *client_username + 3);
 358         memmove (*client_username, end + 1, strlen(end+1)+1);
 359     }
 360
 361     kerberos_status = save_krb5_creds (s, auth_context, ticket->client);
 362
 363     if(!krb5_kuserok (context,
 364                       ticket->client,
 365                       *server_username))
 366         fatal (s, NULL, "Permission denied.");
 367
 368     if (strncmp (*cmd, "-x ", 3) == 0) {
 369         do_encrypt = 1;
 370         memmove (*cmd, *cmd + 3, strlen(*cmd) - 2);
 371     } else {
 372         if(do_encrypt)
 373             fatal (s, NULL, "Encryption is required.");
 374         do_encrypt = 0;
 375     }
 376
 377     {
 378         char *name;
 379
 380         if (krb5_unparse_name (context, ticket->client, &name) == 0) {
 381             char addr_str[256];
 382
 383             if (inet_ntop (thataddr->sa_family,
 384                            socket_get_address (thataddr),
 385                            addr_str, sizeof(addr_str)) == NULL)
 386                 strlcpy (addr_str, "unknown address",
 387                                  sizeof(addr_str));
 388
 389             syslog(LOG_INFO|LOG_AUTH,
 390                    "kerberos v5 shell from %s on %s as %s, cmd '%.80s'",
 391                    name,
 392                    addr_str,
 393                    *server_username,
 394                    *cmd);
 395             free (name);
 396         }
 397     }
 398
 399     return 0;
 400 }
 401 #endif /* KRB5 */
 402
 403 static void
 404 rshd_loop (int from0, int to0,
 405            int to1,   int from1,
 406            int to2,   int from2,
 407            int have_errsock)
 408 {
 409     fd_set real_readset;
 410     int max_fd;
 411     int count = 2;
 412     char *buf;
 413
 414     if(from0 >= FD_SETSIZE || from1 >= FD_SETSIZE || from2 >= FD_SETSIZE)
 415         errx (1, "fd too large");
 416
 417 #ifdef KRB5
 418     if(auth_method == AUTH_KRB5 && protocol_version == 2)
 419         init_ivecs(0, have_errsock);
 420 #endif
 421
 422     FD_ZERO(&real_readset);
 423     FD_SET(from0, &real_readset);
 424     FD_SET(from1, &real_readset);
 425     FD_SET(from2, &real_readset);
 426     max_fd = max(from0, max(from1, from2)) + 1;
 427
 428     buf = malloc(max(RSHD_BUFSIZ, RSH_BUFSIZ));
 429     if (buf == NULL)
 430         syslog_and_die("out of memory");
 431
 432     for (;;) {
 433         int ret;
 434         fd_set readset = real_readset;
 435
 436         ret = select (max_fd, &readset, NULL, NULL, NULL);
 437         if (ret < 0) {
 438             if (errno == EINTR)
 439                 continue;
 440             else
 441                 syslog_and_die ("select: %s", strerror(errno));
 442         }
 443         if (FD_ISSET(from0, &readset)) {
 444             ret = do_read (from0, buf, RSHD_BUFSIZ, ivec_in[0]);
 445             if (ret < 0)
 446                 syslog_and_die ("read: %s", strerror(errno));
 447             else if (ret == 0) {
 448                 close (from0);
 449                 close (to0);
 450                 FD_CLR(from0, &real_readset);
 451             } else
 452                 net_write (to0, buf, ret);
 453         }
 454         if (FD_ISSET(from1, &readset)) {
 455             ret = read (from1, buf, RSH_BUFSIZ);
 456             if (ret < 0)
 457                 syslog_and_die ("read: %s", strerror(errno));
 458             else if (ret == 0) {
 459                 close (from1);
 460                 close (to1);
 461                 FD_CLR(from1, &real_readset);
 462                 if (--count == 0)
 463                     exit (0);
 464             } else
 465                 do_write (to1, buf, ret, ivec_out[0]);
 466         }
 467         if (FD_ISSET(from2, &readset)) {
 468             ret = read (from2, buf, RSH_BUFSIZ);
 469             if (ret < 0)
 470                 syslog_and_die ("read: %s", strerror(errno));
 471             else if (ret == 0) {
 472                 close (from2);
 473                 close (to2);
 474                 FD_CLR(from2, &real_readset);
 475                 if (--count == 0)
 476                     exit (0);
 477             } else
 478                 do_write (to2, buf, ret, ivec_out[1]);
 479         }
 480    }
 481 }
 482
 483 /*
 484  * Used by `setup_copier' to create some pipe-like means of
 485  * communcation.  Real pipes would probably be the best thing, but
 486  * then the shell doesn't understand it's talking to rshd.  If
 487  * socketpair doesn't work everywhere, some autoconf magic would have
 488  * to be added here.
 489  *
 490  * If it fails creating the `pipe', it aborts by calling fatal.
 491  */
 492
 493 static void
 494 pipe_a_like (int fd[2])
 495 {
 496     if (socketpair (AF_UNIX, SOCK_STREAM, 0, fd) < 0)
 497         fatal (STDOUT_FILENO, "socketpair", "Pipe creation failed.");
 498 }
 499
 500 /*
 501  * Start a child process and leave the parent copying data to and from it.  */
 502
 503 static void
 504 setup_copier (int have_errsock)
 505 {
 506     int p0[2], p1[2], p2[2];
 507     pid_t pid;
 508
 509     pipe_a_like(p0);
 510     pipe_a_like(p1);
 511     pipe_a_like(p2);
 512     pid = fork ();
 513     if (pid < 0)
 514         fatal (STDOUT_FILENO, "fork", "Could not create child process.");
 515     if (pid == 0) { /* child */
 516         close (p0[1]);
 517         close (p1[0]);
 518         close (p2[0]);
 519         dup2 (p0[0], STDIN_FILENO);
 520         dup2 (p1[1], STDOUT_FILENO);
 521         dup2 (p2[1], STDERR_FILENO);
 522         close (p0[0]);
 523         close (p1[1]);
 524         close (p2[1]);
 525     } else { /* parent */
 526         close (p0[0]);
 527         close (p1[1]);
 528         close (p2[1]);
 529
 530         if (net_write (STDOUT_FILENO, "", 1) != 1)
 531             fatal (STDOUT_FILENO, "net_write", "Write failure.");
 532
 533         rshd_loop (STDIN_FILENO, p0[1],
 534               STDOUT_FILENO, p1[0],
 535               STDERR_FILENO, p2[0],
 536               have_errsock);
 537     }
 538 }
 539
 540 /*
 541  * Is `port' a ``reserverd'' port?
 542  */
 543
 544 static int
 545 is_reserved(u_short port)
 546 {
 547     return ntohs(port) < IPPORT_RESERVED;
 548 }
 549
 550 /*
 551  * Set the necessary part of the environment in `env'.
 552  */
 553
 554 static void
 555 setup_environment (char ***env, const struct passwd *pwd)
 556 {
 557     int i, j, path;
 558     char **e;
 559
 560     i = 0;
 561     path = 0;
 562     *env = NULL;
 563
 564     i = read_environment(_PATH_ETC_ENVIRONMENT, env);
 565     e = *env;
 566     for (j = 0; j < i; j++) {
 567         if (!strncmp(e[j], "PATH=", 5)) {
 568             path = 1;
 569         }
 570     }
 571
 572     e = *env;
 573     e = realloc(e, (i + 7) * sizeof(char *));
 574
 575     if (asprintf (&e[i++], "USER=%s",  pwd->pw_name) == -1)
 576         syslog_and_die ("asprintf: out of memory");
 577     if (asprintf (&e[i++], "HOME=%s",  pwd->pw_dir) == -1)
 578         syslog_and_die ("asprintf: out of memory");
 579     if (asprintf (&e[i++], "SHELL=%s", pwd->pw_shell) == -1)
 580         syslog_and_die ("asprintf: out of memory");
 581     if (! path) {
 582         if (asprintf (&e[i++], "PATH=%s",  _PATH_DEFPATH) == -1)
 583             syslog_and_die ("asprintf: out of memory");
 584     }
 585     asprintf (&e[i++], "SSH_CLIENT=only_to_make_bash_happy");
 586     if (do_unique_tkfile)
 587         if (asprintf (&e[i++], "KRB5CCNAME=%s", tkfile) == -1)
 588             syslog_and_die ("asprintf: out of memory");
 589     e[i++] = NULL;
 590     *env = e;
 591 }
 592
 593 static void
 594 doit (void)
 595 {
 596     u_char buf[BUFSIZ];
 597     u_char *p;
 598     struct sockaddr_storage thisaddr_ss;
 599     struct sockaddr *thisaddr = (struct sockaddr *)&thisaddr_ss;
 600     struct sockaddr_storage thataddr_ss;
 601     struct sockaddr *thataddr = (struct sockaddr *)&thataddr_ss;
 602     struct sockaddr_storage erraddr_ss;
 603     struct sockaddr *erraddr = (struct sockaddr *)&erraddr_ss;
 604     socklen_t thisaddr_len, thataddr_len;
 605     int port;
 606     int errsock = -1;
 607     char *client_user = NULL, *server_user = NULL, *cmd = NULL;
 608     struct passwd *pwd;
 609     int s = STDIN_FILENO;
 610     char **env;
 611     int ret;
 612     char that_host[NI_MAXHOST];
 613
 614     thisaddr_len = sizeof(thisaddr_ss);
 615     if (getsockname (s, thisaddr, &thisaddr_len) < 0)
 616         syslog_and_die("getsockname: %s", strerror(errno));
 617     thataddr_len = sizeof(thataddr_ss);
 618     if (getpeername (s, thataddr, &thataddr_len) < 0)
 619         syslog_and_die ("getpeername: %s", strerror(errno));
 620
 621     /* check for V4MAPPED addresses? */
 622
 623     if (do_kerberos == 0 && !is_reserved(socket_get_port(thataddr)))
 624         fatal(s, NULL, "Permission denied.");
 625
 626     p = buf;
 627     port = 0;
 628     for(;;) {
 629         if (net_read (s, p, 1) != 1)
 630             syslog_and_die ("reading port number: %s", strerror(errno));
 631         if (*p == '\0')
 632             break;
 633         else if (isdigit(*p))
 634             port = port * 10 + *p - '0';
 635         else
 636             syslog_and_die ("non-digit in port number: %c", *p);
 637     }
 638
 639     if (do_kerberos  == 0 && !is_reserved(htons(port)))
 640         fatal(s, NULL, "Permission denied.");
 641
 642     if (port) {
 643         int priv_port = IPPORT_RESERVED - 1;
 644
 645         /*
 646          * There's no reason to require a ``privileged'' port number
 647          * here, but for some reason the brain dead rsh clients
 648          * do... :-(
 649          */
 650
 651         erraddr->sa_family = thataddr->sa_family;
 652         socket_set_address_and_port (erraddr,
 653                                      socket_get_address (thataddr),
 654                                      htons(port));
 655
 656         /*
 657          * we only do reserved port for IPv4
 658          */
 659
 660         if (erraddr->sa_family == AF_INET)
 661             errsock = rresvport (&priv_port);
 662         else
 663             errsock = socket (erraddr->sa_family, SOCK_STREAM, 0);
 664         if (errsock < 0)
 665             syslog_and_die ("socket: %s", strerror(errno));
 666         if (connect (errsock,
 667                      erraddr,
 668                      socket_sockaddr_size (erraddr)) < 0) {
 669             syslog (LOG_WARNING, "connect: %s", strerror(errno));
 670             close (errsock);
 671         }
 672     }
 673
 674     if(do_kerberos) {
 675         if (net_read (s, buf, 4) != 4)
 676             syslog_and_die ("reading auth info: %s", strerror(errno));
 677
 678 #ifdef KRB5
 679             if((do_kerberos & DO_KRB5) &&
 680                recv_krb5_auth (s, buf, thisaddr, thataddr,
 681                                &client_user,
 682                                &server_user,
 683                                &cmd) == 0)
 684                 auth_method = AUTH_KRB5;
 685             else
 686 #endif /* KRB5 */
 687                 syslog_and_die ("unrecognized auth protocol: %x %x %x %x",
 688                                 buf[0], buf[1], buf[2], buf[3]);
 689     } else {
 690         if(recv_bsd_auth (s, buf,
 691                           (struct sockaddr_in *)thisaddr,
 692                           (struct sockaddr_in *)thataddr,
 693                           &client_user,
 694                           &server_user,
 695                           &cmd) == 0) {
 696             auth_method = AUTH_BROKEN;
 697             if(do_vacuous) {
 698                 printf("Remote host requires Kerberos authentication\n");
 699                 exit(0);
 700             }
 701         } else
 702             syslog_and_die("recv_bsd_auth failed");
 703     }
 704
 705     if (client_user == NULL || server_user == NULL || cmd == NULL)
 706         syslog_and_die("mising client/server/cmd");
 707
 708     pwd = getpwnam (server_user);
 709     if (pwd == NULL)
 710         fatal (s, NULL, "Login incorrect.");
 711
 712     if (*pwd->pw_shell == '\0')
 713         pwd->pw_shell = _PATH_BSHELL;
 714
 715     if (pwd->pw_uid != 0 && access (_PATH_NOLOGIN, F_OK) == 0)
 716         fatal (s, NULL, "Login disabled.");
 717
 718
 719     ret = getnameinfo_verified (thataddr, thataddr_len,
 720                                 that_host, sizeof(that_host),
 721                                 NULL, 0, 0);
 722     if (ret)
 723         fatal (s, NULL, "getnameinfo: %s", gai_strerror(ret));
 724
 725     if (login_access(pwd, that_host) == 0) {
 726         syslog(LOG_NOTICE, "Kerberos rsh denied to %s from %s",
 727                server_user, that_host);
 728         fatal(s, NULL, "Permission denied.");
 729     }
 730
 731 #ifdef HAVE_GETSPNAM
 732     {
 733         struct spwd *sp;
 734         long    today;
 735
 736         sp = getspnam(server_user);
 737         if (sp != NULL) {
 738             today = time(0)/(24L * 60 * 60);
 739             if (sp->sp_expire > 0)
 740                 if (today > sp->sp_expire)
 741                     fatal(s, NULL, "Account has expired.");
 742         }
 743     }
 744 #endif
 745
 746
 747 #ifdef HAVE_SETLOGIN
 748     if (setlogin(pwd->pw_name) < 0)
 749         syslog(LOG_ERR, "setlogin() failed: %s", strerror(errno));
 750 #endif
 751
 752 #ifdef HAVE_SETPCRED
 753     if (setpcred (pwd->pw_name, NULL) == -1)
 754         syslog(LOG_ERR, "setpcred() failure: %s", strerror(errno));
 755 #endif /* HAVE_SETPCRED */
 756
 757     /* Apply limits if not root */
 758     if(pwd->pw_uid != 0) {
 759          const char *file = _PATH_LIMITS_CONF;
 760          read_limits_conf(file, pwd);
 761     }
 762
 763     if (initgroups (pwd->pw_name, pwd->pw_gid) < 0)
 764         fatal (s, "initgroups", "Login incorrect.");
 765
 766     if (setgid(pwd->pw_gid) < 0)
 767         fatal (s, "setgid", "Login incorrect.");
 768
 769     if (setuid (pwd->pw_uid) < 0)
 770         fatal (s, "setuid", "Login incorrect.");
 771
 772     if (chdir (pwd->pw_dir) < 0)
 773         fatal (s, "chdir", "Remote directory.");
 774
 775     if (errsock >= 0) {
 776         if (dup2 (errsock, STDERR_FILENO) < 0)
 777             fatal (s, "dup2", "Cannot dup stderr.");
 778         close (errsock);
 779     } else {
 780         if (dup2 (STDOUT_FILENO, STDERR_FILENO) < 0)
 781             fatal (s, "dup2", "Cannot dup stderr.");
 782     }
 783
 784 #ifdef KRB5
 785     {
 786         int fd;
 787
 788         if (!do_unique_tkfile)
 789             snprintf(tkfile,sizeof(tkfile),"FILE:/tmp/krb5cc_%lu",
 790                      (unsigned long)pwd->pw_uid);
 791         else if (*tkfile=='\0') {
 792             snprintf(tkfile,sizeof(tkfile),"FILE:/tmp/krb5cc_XXXXXX");
 793             fd = mkstemp(tkfile+5);
 794             close(fd);
 795             unlink(tkfile+5);
 796         }
 797
 798         if (kerberos_status)
 799             krb5_start_session();
 800     }
 801 #endif
 802
 803     setup_environment (&env, pwd);
 804
 805     if (do_encrypt) {
 806         setup_copier (errsock >= 0);
 807     } else {
 808         if (net_write (s, "", 1) != 1)
 809             fatal (s, "net_write", "write failed");
 810     }
 811
 812 #if defined(KRB5)
 813     if(k_hasafs()) {
 814         char cell[64];
 815
 816         if(do_newpag)
 817             k_setpag();
 818
 819         /* XXX */
 820        if (kerberos_status) {
 821            krb5_ccache ccache;
 822            krb5_error_code status;
 823
 824            status = krb5_cc_resolve (context, tkfile, &ccache);
 825            if (!status) {
 826                if (k_afs_cell_of_file (pwd->pw_dir, cell, sizeof(cell)) == 0)
 827                    krb5_afslog_uid_home(context, ccache, cell, NULL,
 828                                         pwd->pw_uid, pwd->pw_dir);
 829                krb5_afslog_uid_home(context, ccache, NULL, NULL,
 830                                     pwd->pw_uid, pwd->pw_dir);
 831                krb5_cc_close (context, ccache);
 832            }
 833        }
 834     }
 835 #endif /* KRB5 */
 836     execle (pwd->pw_shell, pwd->pw_shell, "-c", cmd, NULL, env);
 837     err(1, "exec %s", pwd->pw_shell);
 838 }
 839
 840 struct getargs args[] = {
 841     { NULL,             'a',    arg_flag,       &do_addr_verify },
 842     { "keepalive",      'n',    arg_negative_flag,      &do_keepalive },
 843     { "inetd",          'i',    arg_negative_flag,      &do_inetd,
 844       "Not started from inetd" },
 845 #if defined(KRB5)
 846     { "kerberos",       'k',    arg_flag,       &do_kerberos,
 847       "Implement kerberised services" },
 848     { "encrypt",        'x',    arg_flag,               &do_encrypt,
 849       "Implement encrypted service" },
 850 #endif
 851     { "rhosts",         'l',    arg_negative_flag, &do_rhosts,
 852       "Don't check users .rhosts" },
 853     { "port",           'p',    arg_string,     &port_str,      "Use this port",
 854       "port" },
 855     { "vacuous",        'v',    arg_flag, &do_vacuous,
 856       "Don't accept non-kerberised connections" },
 857 #if defined(KRB5)
 858     { NULL,             'P',    arg_negative_flag, &do_newpag,
 859       "Don't put process in new PAG" },
 860 #endif
 861     /* compatibility flag: */
 862     { NULL,             'L',    arg_flag, &do_log },
 863     { "version",        0,      arg_flag,               &do_version },
 864     { "help",           0,      arg_flag,               &do_help }
 865 };
 866
 867 static void
 868 usage (int ret)
 869 {
 870     if(isatty(STDIN_FILENO))
 871         arg_printusage (args,
 872                         sizeof(args) / sizeof(args[0]),
 873                         NULL,
 874                         "");
 875     else
 876         syslog (LOG_ERR, "Usage: %s [-ikxlvPL] [-p port]", getprogname());
 877     exit (ret);
 878 }
 879
 880
 881 int
 882 main(int argc, char **argv)
 883 {
 884     int optind = 0;
 885     int on = 1;
 886
 887     setprogname (argv[0]);
 888     roken_openlog ("rshd", LOG_ODELAY | LOG_PID, LOG_AUTH);
 889
 890     if (getarg(args, sizeof(args) / sizeof(args[0]), argc, argv,
 891                &optind))
 892         usage(1);
 893
 894     if(do_help)
 895         usage (0);
 896
 897     if (do_version) {
 898         print_version(NULL);
 899         exit(0);
 900     }
 901
 902 #if defined(KRB5)
 903     if (do_encrypt)
 904         do_kerberos = 1;
 905
 906     if(do_kerberos)
 907         do_kerberos = DO_KRB5;
 908 #endif
 909
 910 #ifdef KRB5
 911     if((do_kerberos & DO_KRB5) && krb5_init_context (&context) != 0)
 912         do_kerberos &= ~DO_KRB5;
 913 #endif
 914
 915     if (!do_inetd) {
 916         int error;
 917         struct addrinfo *ai = NULL, hints;
 918         char portstr[NI_MAXSERV];
 919
 920         memset (&hints, 0, sizeof(hints));
 921         hints.ai_flags    = AI_PASSIVE;
 922         hints.ai_socktype = SOCK_STREAM;
 923         hints.ai_family   = PF_UNSPEC;
 924
 925         if(port_str != NULL) {
 926             error = getaddrinfo (NULL, port_str, &hints, &ai);
 927             if (error)
 928                 errx (1, "getaddrinfo: %s", gai_strerror (error));
 929         }
 930         if (ai == NULL) {
 931 #if defined(KRB5)
 932             if (do_kerberos) {
 933                 if (do_encrypt) {
 934                     error = getaddrinfo(NULL, "ekshell", &hints, &ai);
 935                     if(error == EAI_NONAME) {
 936                         snprintf(portstr, sizeof(portstr), "%d", 545);
 937                         error = getaddrinfo(NULL, portstr, &hints, &ai);
 938                     }
 939                     if(error)
 940                         errx (1, "getaddrinfo: %s", gai_strerror (error));
 941                 } else {
 942                     error = getaddrinfo(NULL, "kshell", &hints, &ai);
 943                     if(error == EAI_NONAME) {
 944                         snprintf(portstr, sizeof(portstr), "%d", 544);
 945                         error = getaddrinfo(NULL, portstr, &hints, &ai);
 946                     }
 947                     if(error)
 948                         errx (1, "getaddrinfo: %s", gai_strerror (error));
 949                 }
 950             } else
 951 #endif
 952                 {
 953                     error = getaddrinfo(NULL, "shell", &hints, &ai);
 954                     if(error == EAI_NONAME) {
 955                         snprintf(portstr, sizeof(portstr), "%d", 514);
 956                         error = getaddrinfo(NULL, portstr, &hints, &ai);
 957                     }
 958                     if(error)
 959                         errx (1, "getaddrinfo: %s", gai_strerror (error));
 960                 }
 961         }
 962         mini_inetd_addrinfo (ai);
 963         freeaddrinfo(ai);
 964     }
 965
 966     if (do_keepalive &&
 967         setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&on,
 968                    sizeof(on)) < 0)
 969         syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %s", strerror(errno));
 970
 971     /* set SO_LINGER? */
 972
 973     signal (SIGPIPE, SIG_IGN);
 974
 975     doit ();
 976     return 0;
 977 }