session.c

   1 /*
   2  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   3  *                    All rights reserved
   4  *
   5  * As far as I am concerned, the code I have written for this software
   6  * can be used freely for any purpose.  Any derived versions of this
   7  * software must be clearly marked as such, and if the derived work is
   8  * incompatible with the protocol description in the RFC file, it must be
   9  * called by a name other than "ssh" or "Secure Shell".
  10  *
  11  * SSH2 support by Markus Friedl.
  12  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions
  16  * are met:
  17  * 1. Redistributions of source code must retain the above copyright
  18  *    notice, this list of conditions and the following disclaimer.
  19  * 2. Redistributions in binary form must reproduce the above copyright
  20  *    notice, this list of conditions and the following disclaimer in the
  21  *    documentation and/or other materials provided with the distribution.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #include "includes.h"
  36 RCSID("$OpenBSD: session.c,v 1.108 2001/10/11 13:45:21 markus Exp $");
  37
  38 #include "ssh.h"
  39 #include "ssh1.h"
  40 #include "ssh2.h"
  41 #include "xmalloc.h"
  42 #include "sshpty.h"
  43 #include "packet.h"
  44 #include "buffer.h"
  45 #include "mpaux.h"
  46 #include "uidswap.h"
  47 #include "compat.h"
  48 #include "channels.h"
  49 #include "bufaux.h"
  50 #include "auth.h"
  51 #include "auth-options.h"
  52 #include "pathnames.h"
  53 #include "log.h"
  54 #include "servconf.h"
  55 #include "sshlogin.h"
  56 #include "serverloop.h"
  57 #include "canohost.h"
  58 #include "session.h"
  59
  60 #ifdef WITH_IRIX_PROJECT
  61 #include <proj.h>
  62 #endif /* WITH_IRIX_PROJECT */
  63 #ifdef WITH_IRIX_JOBS
  64 #include <sys/resource.h>
  65 #endif
  66 #ifdef WITH_IRIX_AUDIT
  67 #include <sat.h>
  68 #endif /* WITH_IRIX_AUDIT */
  69
  70 #if defined(HAVE_USERSEC_H)
  71 #include <usersec.h>
  72 #endif
  73
  74 #ifdef HAVE_CYGWIN
  75 #include <windows.h>
  76 #include <sys/cygwin.h>
  77 #define is_winnt       (GetVersion() < 0x80000000)
  78 #endif
  79
  80 /* AIX limits */
  81 #if defined(HAVE_GETUSERATTR) && !defined(S_UFSIZE_HARD) && defined(S_UFSIZE)
  82 # define S_UFSIZE_HARD  S_UFSIZE "_hard"
  83 # define S_UCPU_HARD  S_UCPU "_hard"
  84 # define S_UDATA_HARD  S_UDATA "_hard"
  85 # define S_USTACK_HARD  S_USTACK "_hard"
  86 # define S_URSS_HARD  S_URSS "_hard"
  87 # define S_UCORE_HARD  S_UCORE "_hard"
  88 # define S_UNOFILE_HARD S_UNOFILE "_hard"
  89 #endif
  90
  91 #ifdef _AIX
  92 # include <uinfo.h>
  93 #endif
  94
  95 /* types */
  96
  97 #define TTYSZ 64
  98 typedef struct Session Session;
  99 struct Session {
 100         int     used;
 101         int     self;
 102         struct passwd *pw;
 103         Authctxt *authctxt;
 104         pid_t   pid;
 105         /* tty */
 106         char    *term;
 107         int     ptyfd, ttyfd, ptymaster;
 108         int     row, col, xpixel, ypixel;
 109         char    tty[TTYSZ];
 110         /* X11 */
 111         char    *display;
 112         int     screen;
 113         char    *auth_proto;
 114         char    *auth_data;
 115         int     single_connection;
 116         /* proto 2 */
 117         int     chanid;
 118         int     is_subsystem;
 119 };
 120
 121 /* func */
 122
 123 Session *session_new(void);
 124 void    session_set_fds(Session *, int, int, int);
 125 static void     session_pty_cleanup(void *);
 126 void    session_proctitle(Session *);
 127 int     session_setup_x11fwd(Session *);
 128 void    do_exec_pty(Session *, const char *);
 129 void    do_exec_no_pty(Session *, const char *);
 130 void    do_exec(Session *, const char *);
 131 void    do_login(Session *, const char *);
 132 #ifdef LOGIN_NEEDS_UTMPX
 133 static void     do_pre_login(Session *s);
 134 #endif
 135 void    do_child(Session *, const char *);
 136 void    do_motd(void);
 137 int     check_quietlogin(Session *, const char *);
 138
 139 static void do_authenticated1(Authctxt *);
 140 static void do_authenticated2(Authctxt *);
 141
 142 static void session_close(Session *);
 143 static int session_pty_req(Session *);
 144
 145 /* import */
 146 extern ServerOptions options;
 147 extern char *__progname;
 148 extern int log_stderr;
 149 extern int debug_flag;
 150 extern u_int utmp_len;
 151 extern int startup_pipe;
 152 extern void destroy_sensitive_data(void);
 153
 154 /* original command from peer. */
 155 const char *original_command = NULL;
 156
 157 /* data */
 158 #define MAX_SESSIONS 10
 159 Session sessions[MAX_SESSIONS];
 160
 161 #ifdef WITH_AIXAUTHENTICATE
 162 /* AIX's lastlogin message, set in auth1.c */
 163 char *aixloginmsg;
 164 #endif /* WITH_AIXAUTHENTICATE */
 165
 166 #ifdef HAVE_LOGIN_CAP
 167 static login_cap_t *lc;
 168 #endif
 169
 170 void
 171 do_authenticated(Authctxt *authctxt)
 172 {
 173         /*
 174          * Cancel the alarm we set to limit the time taken for
 175          * authentication.
 176          */
 177         alarm(0);
 178         if (startup_pipe != -1) {
 179                 close(startup_pipe);
 180                 startup_pipe = -1;
 181         }
 182 #if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
 183         if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
 184                 error("unable to get login class");
 185                 return;
 186         }
 187 #ifdef BSD_AUTH
 188         if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
 189                 packet_disconnect("Approval failure for %s",
 190                     authctxt->pw->pw_name);
 191         }
 192 #endif
 193 #endif
 194         /* setup the channel layer */
 195         if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
 196                 channel_permit_all_opens();
 197
 198         if (compat20)
 199                 do_authenticated2(authctxt);
 200         else
 201                 do_authenticated1(authctxt);
 202
 203         /* remove agent socket */
 204         if (auth_get_socket_name())
 205                 auth_sock_cleanup_proc(authctxt->pw);
 206 #ifdef KRB4
 207         if (options.kerberos_ticket_cleanup)
 208                 krb4_cleanup_proc(authctxt);
 209 #endif
 210 #ifdef KRB5
 211         if (options.kerberos_ticket_cleanup)
 212                 krb5_cleanup_proc(authctxt);
 213 #endif
 214 }
 215
 216 /*
 217  * Prepares for an interactive session.  This is called after the user has
 218  * been successfully authenticated.  During this message exchange, pseudo
 219  * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
 220  * are requested, etc.
 221  */
 222 static void
 223 do_authenticated1(Authctxt *authctxt)
 224 {
 225         Session *s;
 226         char *command;
 227         int success, type, plen, screen_flag;
 228         int compression_level = 0, enable_compression_after_reply = 0;
 229         u_int proto_len, data_len, dlen;
 230
 231         s = session_new();
 232         s->authctxt = authctxt;
 233         s->pw = authctxt->pw;
 234
 235         /*
 236          * We stay in this loop until the client requests to execute a shell
 237          * or a command.
 238          */
 239         for (;;) {
 240                 success = 0;
 241
 242                 /* Get a packet from the client. */
 243                 type = packet_read(&plen);
 244
 245                 /* Process the packet. */
 246                 switch (type) {
 247                 case SSH_CMSG_REQUEST_COMPRESSION:
 248                         packet_integrity_check(plen, 4, type);
 249                         compression_level = packet_get_int();
 250                         if (compression_level < 1 || compression_level > 9) {
 251                                 packet_send_debug("Received illegal compression level %d.",
 252                                      compression_level);
 253                                 break;
 254                         }
 255                         /* Enable compression after we have responded with SUCCESS. */
 256                         enable_compression_after_reply = 1;
 257                         success = 1;
 258                         break;
 259
 260                 case SSH_CMSG_REQUEST_PTY:
 261                         success = session_pty_req(s);
 262                         break;
 263
 264                 case SSH_CMSG_X11_REQUEST_FORWARDING:
 265                         s->auth_proto = packet_get_string(&proto_len);
 266                         s->auth_data = packet_get_string(&data_len);
 267
 268                         screen_flag = packet_get_protocol_flags() &
 269                             SSH_PROTOFLAG_SCREEN_NUMBER;
 270                         debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
 271
 272                         if (packet_remaining() == 4) {
 273                                 if (!screen_flag)
 274                                         debug2("Buggy client: "
 275                                             "X11 screen flag missing");
 276                                 s->screen = packet_get_int();
 277                         } else {
 278                                 s->screen = 0;
 279                         }
 280                         packet_done();
 281                         success = session_setup_x11fwd(s);
 282                         if (!success) {
 283                                 xfree(s->auth_proto);
 284                                 xfree(s->auth_data);
 285                                 s->auth_proto = NULL;
 286                                 s->auth_data = NULL;
 287                         }
 288                         break;
 289
 290                 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
 291                         if (no_agent_forwarding_flag || compat13) {
 292                                 debug("Authentication agent forwarding not permitted for this authentication.");
 293                                 break;
 294                         }
 295                         debug("Received authentication agent forwarding request.");
 296                         success = auth_input_request_forwarding(s->pw);
 297                         break;
 298
 299                 case SSH_CMSG_PORT_FORWARD_REQUEST:
 300                         if (no_port_forwarding_flag) {
 301                                 debug("Port forwarding not permitted for this authentication.");
 302                                 break;
 303                         }
 304                         if (!options.allow_tcp_forwarding) {
 305                                 debug("Port forwarding not permitted.");
 306                                 break;
 307                         }
 308                         debug("Received TCP/IP port forwarding request.");
 309                         channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
 310                         success = 1;
 311                         break;
 312
 313                 case SSH_CMSG_MAX_PACKET_SIZE:
 314                         if (packet_set_maxsize(packet_get_int()) > 0)
 315                                 success = 1;
 316                         break;
 317
 318 #if defined(AFS) || defined(KRB5)
 319                 case SSH_CMSG_HAVE_KERBEROS_TGT:
 320                         if (!options.kerberos_tgt_passing) {
 321                                 verbose("Kerberos TGT passing disabled.");
 322                         } else {
 323                                 char *kdata = packet_get_string(&dlen);
 324                                 packet_integrity_check(plen, 4 + dlen, type);
 325
 326                                 /* XXX - 0x41, see creds_to_radix version */
 327                                 if (kdata[0] != 0x41) {
 328 #ifdef KRB5
 329                                         krb5_data tgt;
 330                                         tgt.data = kdata;
 331                                         tgt.length = dlen;
 332
 333                                         if (auth_krb5_tgt(s->authctxt, &tgt))
 334                                                 success = 1;
 335                                         else
 336                                                 verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
 337 #endif /* KRB5 */
 338                                 } else {
 339 #ifdef AFS
 340                                         if (auth_krb4_tgt(s->authctxt, kdata))
 341                                                 success = 1;
 342                                         else
 343                                                 verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
 344 #endif /* AFS */
 345                                 }
 346                                 xfree(kdata);
 347                         }
 348                         break;
 349 #endif /* AFS || KRB5 */
 350
 351 #ifdef AFS
 352                 case SSH_CMSG_HAVE_AFS_TOKEN:
 353                         if (!options.afs_token_passing || !k_hasafs()) {
 354                                 verbose("AFS token passing disabled.");
 355                         } else {
 356                                 /* Accept AFS token. */
 357                                 char *token = packet_get_string(&dlen);
 358                                 packet_integrity_check(plen, 4 + dlen, type);
 359
 360                                 if (auth_afs_token(s->authctxt, token))
 361                                         success = 1;
 362                                 else
 363                                         verbose("AFS token refused for %.100s",
 364                                             s->authctxt->user);
 365                                 xfree(token);
 366                         }
 367                         break;
 368 #endif /* AFS */
 369
 370                 case SSH_CMSG_EXEC_SHELL:
 371                 case SSH_CMSG_EXEC_CMD:
 372                         if (type == SSH_CMSG_EXEC_CMD) {
 373                                 command = packet_get_string(&dlen);
 374                                 debug("Exec command '%.500s'", command);
 375                                 do_exec(s, command);
 376                                 xfree(command);
 377                         } else {
 378                                 do_exec(s, NULL);
 379                         }
 380                         packet_done();
 381                         session_close(s);
 382                         return;
 383
 384                 default:
 385                         /*
 386                          * Any unknown messages in this phase are ignored,
 387                          * and a failure message is returned.
 388                          */
 389                         log("Unknown packet type received after authentication: %d", type);
 390                 }
 391                 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
 392                 packet_send();
 393                 packet_write_wait();
 394
 395                 /* Enable compression now that we have replied if appropriate. */
 396                 if (enable_compression_after_reply) {
 397                         enable_compression_after_reply = 0;
 398                         packet_start_compression(compression_level);
 399                 }
 400         }
 401 }
 402
 403 /*
 404  * This is called to fork and execute a command when we have no tty.  This
 405  * will call do_child from the child, and server_loop from the parent after
 406  * setting up file descriptors and such.
 407  */
 408 void
 409 do_exec_no_pty(Session *s, const char *command)
 410 {
 411         int pid;
 412
 413 #ifdef USE_PIPES
 414         int pin[2], pout[2], perr[2];
 415         /* Allocate pipes for communicating with the program. */
 416         if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
 417                 packet_disconnect("Could not create pipes: %.100s",
 418                                   strerror(errno));
 419 #else /* USE_PIPES */
 420         int inout[2], err[2];
 421         /* Uses socket pairs to communicate with the program. */
 422         if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
 423             socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
 424                 packet_disconnect("Could not create socket pairs: %.100s",
 425                                   strerror(errno));
 426 #endif /* USE_PIPES */
 427         if (s == NULL)
 428                 fatal("do_exec_no_pty: no session");
 429
 430         session_proctitle(s);
 431
 432 #if defined(USE_PAM)
 433         do_pam_session(s->pw->pw_name, NULL);
 434         do_pam_setcred(1);
 435         if (is_pam_password_change_required())
 436                 packet_disconnect("Password change required but no "
 437                     "TTY available");
 438 #endif /* USE_PAM */
 439
 440         /* Fork the child. */
 441         if ((pid = fork()) == 0) {
 442                 /* Child.  Reinitialize the log since the pid has changed. */
 443                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 444
 445                 /*
 446                  * Create a new session and process group since the 4.4BSD
 447                  * setlogin() affects the entire process group.
 448                  */
 449                 if (setsid() < 0)
 450                         error("setsid failed: %.100s", strerror(errno));
 451
 452 #ifdef USE_PIPES
 453                 /*
 454                  * Redirect stdin.  We close the parent side of the socket
 455                  * pair, and make the child side the standard input.
 456                  */
 457                 close(pin[1]);
 458                 if (dup2(pin[0], 0) < 0)
 459                         perror("dup2 stdin");
 460                 close(pin[0]);
 461
 462                 /* Redirect stdout. */
 463                 close(pout[0]);
 464                 if (dup2(pout[1], 1) < 0)
 465                         perror("dup2 stdout");
 466                 close(pout[1]);
 467
 468                 /* Redirect stderr. */
 469                 close(perr[0]);
 470                 if (dup2(perr[1], 2) < 0)
 471                         perror("dup2 stderr");
 472                 close(perr[1]);
 473 #else /* USE_PIPES */
 474                 /*
 475                  * Redirect stdin, stdout, and stderr.  Stdin and stdout will
 476                  * use the same socket, as some programs (particularly rdist)
 477                  * seem to depend on it.
 478                  */
 479                 close(inout[1]);
 480                 close(err[1]);
 481                 if (dup2(inout[0], 0) < 0)      /* stdin */
 482                         perror("dup2 stdin");
 483                 if (dup2(inout[0], 1) < 0)      /* stdout.  Note: same socket as stdin. */
 484                         perror("dup2 stdout");
 485                 if (dup2(err[0], 2) < 0)        /* stderr */
 486                         perror("dup2 stderr");
 487 #endif /* USE_PIPES */
 488
 489                 /* Do processing for the child (exec command etc). */
 490                 do_child(s, command);
 491                 /* NOTREACHED */
 492         }
 493 #ifdef HAVE_CYGWIN
 494         if (is_winnt)
 495                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 496 #endif
 497         if (pid < 0)
 498                 packet_disconnect("fork failed: %.100s", strerror(errno));
 499         s->pid = pid;
 500         /* Set interactive/non-interactive mode. */
 501         packet_set_interactive(s->display != NULL);
 502 #ifdef USE_PIPES
 503         /* We are the parent.  Close the child sides of the pipes. */
 504         close(pin[0]);
 505         close(pout[1]);
 506         close(perr[1]);
 507
 508         if (compat20) {
 509                 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
 510         } else {
 511                 /* Enter the interactive session. */
 512                 server_loop(pid, pin[1], pout[0], perr[0]);
 513                 /* server_loop has closed pin[1], pout[0], and perr[0]. */
 514         }
 515 #else /* USE_PIPES */
 516         /* We are the parent.  Close the child sides of the socket pairs. */
 517         close(inout[0]);
 518         close(err[0]);
 519
 520         /*
 521          * Enter the interactive session.  Note: server_loop must be able to
 522          * handle the case that fdin and fdout are the same.
 523          */
 524         if (compat20) {
 525                 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
 526         } else {
 527                 server_loop(pid, inout[1], inout[1], err[1]);
 528                 /* server_loop has closed inout[1] and err[1]. */
 529         }
 530 #endif /* USE_PIPES */
 531 }
 532
 533 /*
 534  * This is called to fork and execute a command when we have a tty.  This
 535  * will call do_child from the child, and server_loop from the parent after
 536  * setting up file descriptors, controlling tty, updating wtmp, utmp,
 537  * lastlog, and other such operations.
 538  */
 539 void
 540 do_exec_pty(Session *s, const char *command)
 541 {
 542         int fdout, ptyfd, ttyfd, ptymaster;
 543         pid_t pid;
 544
 545         if (s == NULL)
 546                 fatal("do_exec_pty: no session");
 547         ptyfd = s->ptyfd;
 548         ttyfd = s->ttyfd;
 549
 550 #if defined(USE_PAM)
 551         do_pam_session(s->pw->pw_name, s->tty);
 552         do_pam_setcred(1);
 553 #endif
 554
 555         /* Fork the child. */
 556         if ((pid = fork()) == 0) {
 557
 558                 /* Child.  Reinitialize the log because the pid has changed. */
 559                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 560                 /* Close the master side of the pseudo tty. */
 561                 close(ptyfd);
 562
 563                 /* Make the pseudo tty our controlling tty. */
 564                 pty_make_controlling_tty(&ttyfd, s->tty);
 565
 566                 /* Redirect stdin/stdout/stderr from the pseudo tty. */
 567                 if (dup2(ttyfd, 0) < 0)
 568                         error("dup2 stdin: %s", strerror(errno));
 569                 if (dup2(ttyfd, 1) < 0)
 570                         error("dup2 stdout: %s", strerror(errno));
 571                 if (dup2(ttyfd, 2) < 0)
 572                         error("dup2 stderr: %s", strerror(errno));
 573
 574                 /* Close the extra descriptor for the pseudo tty. */
 575                 close(ttyfd);
 576
 577                 /* record login, etc. similar to login(1) */
 578 #ifndef HAVE_OSF_SIA
 579                 if (!(options.use_login && command == NULL))
 580                         do_login(s, command);
 581 # ifdef LOGIN_NEEDS_UTMPX
 582                 else
 583                         do_pre_login(s);
 584 # endif
 585 #endif
 586
 587                 /* Do common processing for the child, such as execing the command. */
 588                 do_child(s, command);
 589                 /* NOTREACHED */
 590         }
 591 #ifdef HAVE_CYGWIN
 592         if (is_winnt)
 593                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 594 #endif
 595         if (pid < 0)
 596                 packet_disconnect("fork failed: %.100s", strerror(errno));
 597         s->pid = pid;
 598
 599         /* Parent.  Close the slave side of the pseudo tty. */
 600         close(ttyfd);
 601
 602         /*
 603          * Create another descriptor of the pty master side for use as the
 604          * standard input.  We could use the original descriptor, but this
 605          * simplifies code in server_loop.  The descriptor is bidirectional.
 606          */
 607         fdout = dup(ptyfd);
 608         if (fdout < 0)
 609                 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
 610
 611         /* we keep a reference to the pty master */
 612         ptymaster = dup(ptyfd);
 613         if (ptymaster < 0)
 614                 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
 615         s->ptymaster = ptymaster;
 616
 617         /* Enter interactive session. */
 618         packet_set_interactive(1);
 619         if (compat20) {
 620                 session_set_fds(s, ptyfd, fdout, -1);
 621         } else {
 622                 server_loop(pid, ptyfd, fdout, -1);
 623                 /* server_loop _has_ closed ptyfd and fdout. */
 624         }
 625 }
 626
 627 #ifdef LOGIN_NEEDS_UTMPX
 628 static void
 629 do_pre_login(Session *s)
 630 {
 631         socklen_t fromlen;
 632         struct sockaddr_storage from;
 633         pid_t pid = getpid();
 634
 635         /*
 636          * Get IP address of client. If the connection is not a socket, let
 637          * the address be 0.0.0.0.
 638          */
 639         memset(&from, 0, sizeof(from));
 640         if (packet_connection_is_on_socket()) {
 641                 fromlen = sizeof(from);
 642                 if (getpeername(packet_get_connection_in(),
 643                      (struct sockaddr *) & from, &fromlen) < 0) {
 644                         debug("getpeername: %.100s", strerror(errno));
 645                         fatal_cleanup();
 646                 }
 647         }
 648
 649         record_utmp_only(pid, s->tty, s->pw->pw_name,
 650             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 651             (struct sockaddr *)&from);
 652 }
 653 #endif
 654
 655 /*
 656  * This is called to fork and execute a command.  If another command is
 657  * to be forced, execute that instead.
 658  */
 659 void
 660 do_exec(Session *s, const char *command)
 661 {
 662         if (forced_command) {
 663                 original_command = command;
 664                 command = forced_command;
 665                 debug("Forced command '%.900s'", command);
 666         }
 667
 668         if (s->ttyfd != -1)
 669                 do_exec_pty(s, command);
 670         else
 671                 do_exec_no_pty(s, command);
 672
 673         original_command = NULL;
 674 }
 675
 676 /* administrative, login(1)-like work */
 677 void
 678 do_login(Session *s, const char *command)
 679 {
 680         char *time_string;
 681         char hostname[MAXHOSTNAMELEN];
 682         socklen_t fromlen;
 683         struct sockaddr_storage from;
 684         time_t last_login_time;
 685         struct passwd * pw = s->pw;
 686         pid_t pid = getpid();
 687
 688         /*
 689          * Get IP address of client. If the connection is not a socket, let
 690          * the address be 0.0.0.0.
 691          */
 692         memset(&from, 0, sizeof(from));
 693         if (packet_connection_is_on_socket()) {
 694                 fromlen = sizeof(from);
 695                 if (getpeername(packet_get_connection_in(),
 696                      (struct sockaddr *) & from, &fromlen) < 0) {
 697                         debug("getpeername: %.100s", strerror(errno));
 698                         fatal_cleanup();
 699                 }
 700         }
 701
 702         /* Get the time and hostname when the user last logged in. */
 703         if (options.print_lastlog) {
 704                 hostname[0] = '\0';
 705                 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
 706                     hostname, sizeof(hostname));
 707         }
 708
 709         /* Record that there was a login on that tty from the remote host. */
 710         record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
 711             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 712             (struct sockaddr *)&from);
 713
 714 #ifdef USE_PAM
 715         /*
 716          * If password change is needed, do it now.
 717          * This needs to occur before the ~/.hushlogin check.
 718          */
 719         if (is_pam_password_change_required()) {
 720                 print_pam_messages();
 721                 do_pam_chauthtok();
 722         }
 723 #endif
 724
 725         if (check_quietlogin(s, command))
 726                 return;
 727
 728 #ifdef USE_PAM
 729         if (!is_pam_password_change_required())
 730                 print_pam_messages();
 731 #endif /* USE_PAM */
 732 #ifdef WITH_AIXAUTHENTICATE
 733         if (aixloginmsg && *aixloginmsg)
 734                 printf("%s\n", aixloginmsg);
 735 #endif /* WITH_AIXAUTHENTICATE */
 736
 737         if (options.print_lastlog && last_login_time != 0) {
 738                 time_string = ctime(&last_login_time);
 739                 if (strchr(time_string, '\n'))
 740                         *strchr(time_string, '\n') = 0;
 741                 if (strcmp(hostname, "") == 0)
 742                         printf("Last login: %s\r\n", time_string);
 743                 else
 744                         printf("Last login: %s from %s\r\n", time_string, hostname);
 745         }
 746
 747         do_motd();
 748 }
 749
 750 /*
 751  * Display the message of the day.
 752  */
 753 void
 754 do_motd(void)
 755 {
 756         FILE *f;
 757         char buf[256];
 758
 759         if (options.print_motd) {
 760 #ifdef HAVE_LOGIN_CAP
 761                 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
 762                     "/etc/motd"), "r");
 763 #else
 764                 f = fopen("/etc/motd", "r");
 765 #endif
 766                 if (f) {
 767                         while (fgets(buf, sizeof(buf), f))
 768                                 fputs(buf, stdout);
 769                         fclose(f);
 770                 }
 771         }
 772 }
 773
 774
 775 /*
 776  * Check for quiet login, either .hushlogin or command given.
 777  */
 778 int
 779 check_quietlogin(Session *s, const char *command)
 780 {
 781         char buf[256];
 782         struct passwd *pw = s->pw;
 783         struct stat st;
 784
 785         /* Return 1 if .hushlogin exists or a command given. */
 786         if (command != NULL)
 787                 return 1;
 788         snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
 789 #ifdef HAVE_LOGIN_CAP
 790         if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
 791                 return 1;
 792 #else
 793         if (stat(buf, &st) >= 0)
 794                 return 1;
 795 #endif
 796         return 0;
 797 }
 798
 799 /*
 800  * Sets the value of the given variable in the environment.  If the variable
 801  * already exists, its value is overriden.
 802  */
 803 static void
 804 child_set_env(char ***envp, u_int *envsizep, const char *name,
 805               const char *value)
 806 {
 807         u_int i, namelen;
 808         char **env;
 809
 810         /*
 811          * Find the slot where the value should be stored.  If the variable
 812          * already exists, we reuse the slot; otherwise we append a new slot
 813          * at the end of the array, expanding if necessary.
 814          */
 815         env = *envp;
 816         namelen = strlen(name);
 817         for (i = 0; env[i]; i++)
 818                 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
 819                         break;
 820         if (env[i]) {
 821                 /* Reuse the slot. */
 822                 xfree(env[i]);
 823         } else {
 824                 /* New variable.  Expand if necessary. */
 825                 if (i >= (*envsizep) - 1) {
 826                         (*envsizep) += 50;
 827                         env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
 828                 }
 829                 /* Need to set the NULL pointer at end of array beyond the new slot. */
 830                 env[i + 1] = NULL;
 831         }
 832
 833         /* Allocate space and format the variable in the appropriate slot. */
 834         env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
 835         snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
 836 }
 837
 838 /*
 839  * Reads environment variables from the given file and adds/overrides them
 840  * into the environment.  If the file does not exist, this does nothing.
 841  * Otherwise, it must consist of empty lines, comments (line starts with '#')
 842  * and assignments of the form name=value.  No other forms are allowed.
 843  */
 844 static void
 845 read_environment_file(char ***env, u_int *envsize,
 846                       const char *filename)
 847 {
 848         FILE *f;
 849         char buf[4096];
 850         char *cp, *value;
 851
 852         f = fopen(filename, "r");
 853         if (!f)
 854                 return;
 855
 856         while (fgets(buf, sizeof(buf), f)) {
 857                 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
 858                         ;
 859                 if (!*cp || *cp == '#' || *cp == '\n')
 860                         continue;
 861                 if (strchr(cp, '\n'))
 862                         *strchr(cp, '\n') = '\0';
 863                 value = strchr(cp, '=');
 864                 if (value == NULL) {
 865                         fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
 866                         continue;
 867                 }
 868                 /*
 869                  * Replace the equals sign by nul, and advance value to
 870                  * the value string.
 871                  */
 872                 *value = '\0';
 873                 value++;
 874                 child_set_env(env, envsize, cp, value);
 875         }
 876         fclose(f);
 877 }
 878
 879 #ifdef USE_PAM
 880 /*
 881  * Sets any environment variables which have been specified by PAM
 882  */
 883 void do_pam_environment(char ***env, u_int *envsize)
 884 {
 885         char *equals, var_name[512], var_val[512];
 886         char **pam_env;
 887         int i;
 888
 889         if ((pam_env = fetch_pam_environment()) == NULL)
 890                 return;
 891
 892         for(i = 0; pam_env[i] != NULL; i++) {
 893                 if ((equals = strstr(pam_env[i], "=")) == NULL)
 894                         continue;
 895
 896                 if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) {
 897                         memset(var_name, '\0', sizeof(var_name));
 898                         memset(var_val, '\0', sizeof(var_val));
 899
 900                         strncpy(var_name, pam_env[i], equals - pam_env[i]);
 901                         strcpy(var_val, equals + 1);
 902
 903                         debug3("PAM environment: %s=%s", var_name, var_val);
 904
 905                         child_set_env(env, envsize, var_name, var_val);
 906                 }
 907         }
 908 }
 909 #endif /* USE_PAM */
 910
 911 #ifdef HAVE_CYGWIN
 912 void copy_environment(char ***env, u_int *envsize)
 913 {
 914         char *equals, var_name[512], var_val[512];
 915         int i;
 916
 917         for(i = 0; environ[i] != NULL; i++) {
 918                 if ((equals = strstr(environ[i], "=")) == NULL)
 919                         continue;
 920
 921                 if (strlen(environ[i]) < (sizeof(var_name) - 1)) {
 922                         memset(var_name, '\0', sizeof(var_name));
 923                         memset(var_val, '\0', sizeof(var_val));
 924
 925                         strncpy(var_name, environ[i], equals - environ[i]);
 926                         strcpy(var_val, equals + 1);
 927
 928                         debug3("Copy environment: %s=%s", var_name, var_val);
 929
 930                         child_set_env(env, envsize, var_name, var_val);
 931                 }
 932         }
 933 }
 934 #endif
 935
 936 #if defined(HAVE_GETUSERATTR)
 937 /*
 938  * AIX-specific login initialisation
 939  */
 940 void set_limit(char *user, char *soft, char *hard, int resource, int mult)
 941 {
 942         struct rlimit rlim;
 943         int slim, hlim;
 944
 945         getrlimit(resource, &rlim);
 946
 947         slim = 0;
 948         if (getuserattr(user, soft, &slim, SEC_INT) != -1) {
 949                 if (slim < 0) {
 950                         rlim.rlim_cur = RLIM_INFINITY;
 951                 } else if (slim != 0) {
 952                         /* See the wackiness below */
 953                         if (rlim.rlim_cur == slim * mult)
 954                                 slim = 0;
 955                         else
 956                                 rlim.rlim_cur = slim * mult;
 957                 }
 958         }
 959
 960         hlim = 0;
 961         if (getuserattr(user, hard, &hlim, SEC_INT) != -1) {
 962                 if (hlim < 0) {
 963                         rlim.rlim_max = RLIM_INFINITY;
 964                 } else if (hlim != 0) {
 965                         rlim.rlim_max = hlim * mult;
 966                 }
 967         }
 968
 969         /*
 970          * XXX For cpu and fsize the soft limit is set to the hard limit
 971          * if the hard limit is left at its default value and the soft limit
 972          * is changed from its default value, either by requesting it
 973          * (slim == 0) or by setting it to the current default.  At least
 974          * that's how rlogind does it.  If you're confused you're not alone.
 975          * Bug or feature? AIX 4.3.1.2
 976          */
 977         if ((!strcmp(soft, "fsize") || !strcmp(soft, "cpu"))
 978             && hlim == 0 && slim != 0)
 979                 rlim.rlim_max = rlim.rlim_cur;
 980         /* A specified hard limit limits the soft limit */
 981         else if (hlim > 0 && rlim.rlim_cur > rlim.rlim_max)
 982                 rlim.rlim_cur = rlim.rlim_max;
 983         /* A soft limit can increase a hard limit */
 984         else if (rlim.rlim_cur > rlim.rlim_max)
 985                 rlim.rlim_max = rlim.rlim_cur;
 986
 987         if (setrlimit(resource, &rlim) != 0)
 988                 error("setrlimit(%.10s) failed: %.100s", soft, strerror(errno));
 989 }
 990
 991 void set_limits_from_userattr(char *user)
 992 {
 993         int mask;
 994         char buf[16];
 995
 996         set_limit(user, S_UFSIZE, S_UFSIZE_HARD, RLIMIT_FSIZE, 512);
 997         set_limit(user, S_UCPU, S_UCPU_HARD, RLIMIT_CPU, 1);
 998         set_limit(user, S_UDATA, S_UDATA_HARD, RLIMIT_DATA, 512);
 999         set_limit(user, S_USTACK, S_USTACK_HARD, RLIMIT_STACK, 512);
1000         set_limit(user, S_URSS, S_URSS_HARD, RLIMIT_RSS, 512);
1001         set_limit(user, S_UCORE, S_UCORE_HARD, RLIMIT_CORE, 512);
1002 #if defined(S_UNOFILE)
1003         set_limit(user, S_UNOFILE, S_UNOFILE_HARD, RLIMIT_NOFILE, 1);
1004 #endif
1005
1006         if (getuserattr(user, S_UMASK, &mask, SEC_INT) != -1) {
1007                 /* Convert decimal to octal */
1008                 (void) snprintf(buf, sizeof(buf), "%d", mask);
1009                 if (sscanf(buf, "%o", &mask) == 1)
1010                         umask(mask);
1011         }
1012 }
1013 #endif /* defined(HAVE_GETUSERATTR) */
1014
1015 /*
1016  * Performs common processing for the child, such as setting up the
1017  * environment, closing extra file descriptors, setting the user and group
1018  * ids, and executing the command or shell.
1019  */
1020 void
1021 do_child(Session *s, const char *command)
1022 {
1023         const char *shell, *hostname = NULL, *cp = NULL;
1024         struct passwd *pw = s->pw;
1025         char buf[256];
1026         char cmd[1024];
1027         FILE *f = NULL;
1028         u_int envsize, i;
1029         char **env;
1030         extern char **environ;
1031         struct stat st;
1032         char *argv[10];
1033         int do_xauth;
1034 #ifdef WITH_IRIX_PROJECT
1035         prid_t projid;
1036 #endif /* WITH_IRIX_PROJECT */
1037 #ifdef WITH_IRIX_JOBS
1038         jid_t jid = 0;
1039 #else
1040 #ifdef WITH_IRIX_ARRAY
1041         int jid = 0;
1042 #endif /* WITH_IRIX_ARRAY */
1043 #endif /* WITH_IRIX_JOBS */
1044
1045         do_xauth =
1046             s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1047
1048         /* remove hostkey from the child's memory */
1049         destroy_sensitive_data();
1050
1051         /* login(1) is only called if we execute the login shell */
1052         if (options.use_login && command != NULL)
1053                 options.use_login = 0;
1054
1055 #if !defined(HAVE_OSF_SIA)
1056         if (!options.use_login) {
1057 # ifdef HAVE_LOGIN_CAP
1058                 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1059                         f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1060                             _PATH_NOLOGIN), "r");
1061 # else /* HAVE_LOGIN_CAP */
1062                 if (pw->pw_uid)
1063                         f = fopen(_PATH_NOLOGIN, "r");
1064 # endif /* HAVE_LOGIN_CAP */
1065                 if (f) {
1066                         /* /etc/nologin exists.  Print its contents and exit. */
1067                         while (fgets(buf, sizeof(buf), f))
1068                                 fputs(buf, stderr);
1069                         fclose(f);
1070                         exit(254);
1071                 }
1072         }
1073 #endif /* HAVE_OSF_SIA */
1074
1075         /* Set login name, uid, gid, and groups. */
1076         /* Login(1) does this as well, and it needs uid 0 for the "-h"
1077            switch, so we let login(1) to this for us. */
1078         if (!options.use_login) {
1079 #ifdef HAVE_OSF_SIA
1080                 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1081                 if (!check_quietlogin(s, command))
1082                         do_motd();
1083 #else /* HAVE_OSF_SIA */
1084 #ifdef HAVE_CYGWIN
1085                 if (is_winnt) {
1086 #else
1087                 if (getuid() == 0 || geteuid() == 0) {
1088 #endif
1089 # ifdef HAVE_GETUSERATTR
1090                         set_limits_from_userattr(pw->pw_name);
1091 # endif /* HAVE_GETUSERATTR */
1092 # ifdef HAVE_LOGIN_CAP
1093                         if (setusercontext(lc, pw, pw->pw_uid,
1094                             (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1095                                 perror("unable to set user context");
1096                                 exit(1);
1097                         }
1098 # else /* HAVE_LOGIN_CAP */
1099 #if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1100                         /* Sets login uid for accounting */
1101                         if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1102                                 error("setluid: %s", strerror(errno));
1103 #endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1104
1105                         if (setlogin(pw->pw_name) < 0)
1106                                 error("setlogin failed: %s", strerror(errno));
1107                         if (setgid(pw->pw_gid) < 0) {
1108                                 perror("setgid");
1109                                 exit(1);
1110                         }
1111                         /* Initialize the group list. */
1112                         if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1113                                 perror("initgroups");
1114                                 exit(1);
1115                         }
1116                         endgrent();
1117 #  ifdef USE_PAM
1118                         /*
1119                          * PAM credentials may take the form of
1120                          * supplementary groups. These will have been
1121                          * wiped by the above initgroups() call.
1122                          * Reestablish them here.
1123                          */
1124                         do_pam_setcred(0);
1125 #  endif /* USE_PAM */
1126 #  ifdef WITH_IRIX_JOBS
1127                         jid = jlimit_startjob(pw->pw_name, pw->pw_uid, "interactive");
1128                         if (jid == -1) {
1129                                 fatal("Failed to create job container: %.100s",
1130                                       strerror(errno));
1131                         }
1132 #  endif /* WITH_IRIX_JOBS */
1133 #  ifdef WITH_IRIX_ARRAY
1134                         /* initialize array session */
1135                         if (jid == 0) {
1136                                 if (newarraysess() != 0)
1137                                         fatal("Failed to set up new array session: %.100s",
1138                                               strerror(errno));
1139                         }
1140 #  endif /* WITH_IRIX_ARRAY */
1141 #  ifdef WITH_IRIX_PROJECT
1142                         /* initialize irix project info */
1143                         if ((projid = getdfltprojuser(pw->pw_name)) == -1) {
1144                           debug("Failed to get project id, using projid 0");
1145                           projid = 0;
1146                         }
1147                         if (setprid(projid))
1148                           fatal("Failed to initialize project %d for %s: %.100s",
1149                                 (int)projid, pw->pw_name, strerror(errno));
1150 #  endif /* WITH_IRIX_PROJECT */
1151 #ifdef WITH_IRIX_AUDIT
1152                         if (sysconf(_SC_AUDIT)) {
1153                                 debug("Setting sat id to %d", (int) pw->pw_uid);
1154                                 if (satsetid(pw->pw_uid))
1155                                         debug("error setting satid: %.100s", strerror(errno));
1156                         }
1157 #endif /* WITH_IRIX_AUDIT */
1158
1159 #ifdef _AIX
1160                         /*
1161                          * AIX has a "usrinfo" area where logname and
1162                          * other stuff is stored - a few applications
1163                          * actually use this and die if it's not set
1164                          */
1165                         if (s->ttyfd == -1)
1166                                 s->tty[0] = '\0';
1167                         cp = xmalloc(22 + strlen(s->tty) +
1168                             2 * strlen(pw->pw_name));
1169                         i = sprintf(cp, "LOGNAME=%s%cNAME=%s%cTTY=%s%c%c",
1170                             pw->pw_name, 0, pw->pw_name, 0, s->tty, 0, 0);
1171                         if (usrinfo(SETUINFO, cp, i) == -1)
1172                                 fatal("Couldn't set usrinfo: %s",
1173                                     strerror(errno));
1174                         debug3("AIX/UsrInfo: set len %d", i);
1175                         xfree(cp);
1176 #endif
1177
1178                         /* Permanently switch to the desired uid. */
1179                         permanently_set_uid(pw);
1180 # endif /* HAVE_LOGIN_CAP */
1181                 }
1182 #endif /* HAVE_OSF_SIA */
1183
1184 #ifdef HAVE_CYGWIN
1185                 if (is_winnt)
1186 #endif
1187                 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1188                         fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1189         }
1190         /*
1191          * Get the shell from the password data.  An empty shell field is
1192          * legal, and means /bin/sh.
1193          */
1194         shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1195 #ifdef HAVE_LOGIN_CAP
1196         shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1197 #endif
1198
1199         /* Initialize the environment. */
1200         envsize = 100;
1201         env = xmalloc(envsize * sizeof(char *));
1202         env[0] = NULL;
1203
1204 #ifdef HAVE_CYGWIN
1205         /*
1206          * The Windows environment contains some setting which are
1207          * important for a running system. They must not be dropped.
1208          */
1209         copy_environment(&env, &envsize);
1210 #endif
1211
1212         if (!options.use_login) {
1213                 /* Set basic environment. */
1214                 child_set_env(&env, &envsize, "USER", pw->pw_name);
1215                 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1216                 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1217 #ifdef HAVE_LOGIN_CAP
1218                 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
1219                 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1220 #else /* HAVE_LOGIN_CAP */
1221 # ifndef HAVE_CYGWIN
1222                 /*
1223                  * There's no standard path on Windows. The path contains
1224                  * important components pointing to the system directories,
1225                  * needed for loading shared libraries. So the path better
1226                  * remains intact here.
1227                  */
1228                 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1229 # endif /* HAVE_CYGWIN */
1230 #endif /* HAVE_LOGIN_CAP */
1231
1232                 snprintf(buf, sizeof buf, "%.200s/%.50s",
1233                          _PATH_MAILDIR, pw->pw_name);
1234                 child_set_env(&env, &envsize, "MAIL", buf);
1235
1236                 /* Normal systems set SHELL by default. */
1237                 child_set_env(&env, &envsize, "SHELL", shell);
1238         }
1239         if (getenv("TZ"))
1240                 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1241
1242         /* Set custom environment options from RSA authentication. */
1243         while (custom_environment) {
1244                 struct envstring *ce = custom_environment;
1245                 char *s = ce->s;
1246                 int i;
1247                 for (i = 0; s[i] != '=' && s[i]; i++);
1248                 if (s[i] == '=') {
1249                         s[i] = 0;
1250                         child_set_env(&env, &envsize, s, s + i + 1);
1251                 }
1252                 custom_environment = ce->next;
1253                 xfree(ce->s);
1254                 xfree(ce);
1255         }
1256
1257         snprintf(buf, sizeof buf, "%.50s %d %d",
1258                  get_remote_ipaddr(), get_remote_port(), get_local_port());
1259         child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1260
1261         if (s->ttyfd != -1)
1262                 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1263         if (s->term)
1264                 child_set_env(&env, &envsize, "TERM", s->term);
1265         if (s->display)
1266                 child_set_env(&env, &envsize, "DISPLAY", s->display);
1267         if (original_command)
1268                 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1269                     original_command);
1270
1271 #ifdef _AIX
1272         if ((cp = getenv("AUTHSTATE")) != NULL)
1273                 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1274         if ((cp = getenv("KRB5CCNAME")) != NULL)
1275                 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1276         read_environment_file(&env, &envsize, "/etc/environment");
1277 #endif
1278 #ifdef KRB4
1279         if (s->authctxt->krb4_ticket_file)
1280                 child_set_env(&env, &envsize, "KRBTKFILE",
1281                     s->authctxt->krb4_ticket_file);
1282 #endif
1283 #ifdef KRB5
1284         if (s->authctxt->krb5_ticket_file)
1285                 child_set_env(&env, &envsize, "KRB5CCNAME",
1286                     s->authctxt->krb5_ticket_file);
1287 #endif
1288 #ifdef USE_PAM
1289         /* Pull in any environment variables that may have been set by PAM. */
1290         do_pam_environment(&env, &envsize);
1291 #endif /* USE_PAM */
1292
1293         if (auth_get_socket_name() != NULL)
1294                 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1295                               auth_get_socket_name());
1296
1297         /* read $HOME/.ssh/environment. */
1298         if (!options.use_login) {
1299                 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1300                     pw->pw_dir);
1301                 read_environment_file(&env, &envsize, buf);
1302         }
1303         if (debug_flag) {
1304                 /* dump the environment */
1305                 fprintf(stderr, "Environment:\n");
1306                 for (i = 0; env[i]; i++)
1307                         fprintf(stderr, "  %.200s\n", env[i]);
1308         }
1309         /* we have to stash the hostname before we close our socket. */
1310         if (options.use_login)
1311                 hostname = get_remote_name_or_ip(utmp_len,
1312                     options.reverse_mapping_check);
1313         /*
1314          * Close the connection descriptors; note that this is the child, and
1315          * the server will still have the socket open, and it is important
1316          * that we do not shutdown it.  Note that the descriptors cannot be
1317          * closed before building the environment, as we call
1318          * get_remote_ipaddr there.
1319          */
1320         if (packet_get_connection_in() == packet_get_connection_out())
1321                 close(packet_get_connection_in());
1322         else {
1323                 close(packet_get_connection_in());
1324                 close(packet_get_connection_out());
1325         }
1326         /*
1327          * Close all descriptors related to channels.  They will still remain
1328          * open in the parent.
1329          */
1330         /* XXX better use close-on-exec? -markus */
1331         channel_close_all();
1332
1333         /*
1334          * Close any extra file descriptors.  Note that there may still be
1335          * descriptors left by system functions.  They will be closed later.
1336          */
1337         endpwent();
1338
1339         /*
1340          * Close any extra open file descriptors so that we don\'t have them
1341          * hanging around in clients.  Note that we want to do this after
1342          * initgroups, because at least on Solaris 2.3 it leaves file
1343          * descriptors open.
1344          */
1345         for (i = 3; i < 64; i++)
1346                 close(i);
1347
1348         /*
1349          * Must take new environment into use so that .ssh/rc, /etc/sshrc and
1350          * xauth are run in the proper environment.
1351          */
1352         environ = env;
1353
1354 #ifdef AFS
1355         /* Try to get AFS tokens for the local cell. */
1356         if (k_hasafs()) {
1357                 char cell[64];
1358
1359                 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1360                         krb_afslog(cell, 0);
1361
1362                 krb_afslog(0, 0);
1363         }
1364 #endif /* AFS */
1365
1366         /* Change current directory to the user\'s home directory. */
1367         if (chdir(pw->pw_dir) < 0) {
1368                 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1369                     pw->pw_dir, strerror(errno));
1370 #ifdef HAVE_LOGIN_CAP
1371                 if (login_getcapbool(lc, "requirehome", 0))
1372                         exit(1);
1373 #endif
1374         }
1375
1376         /*
1377          * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
1378          * in this order).
1379          */
1380         if (!options.use_login) {
1381                 /* ignore _PATH_SSH_USER_RC for subsystems */
1382                 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1383                         snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1384                             shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1385                         if (debug_flag)
1386                                 fprintf(stderr, "Running %s\n", cmd);
1387                         f = popen(cmd, "w");
1388                         if (f) {
1389                                 if (do_xauth)
1390                                         fprintf(f, "%s %s\n", s->auth_proto,
1391                                             s->auth_data);
1392                                 pclose(f);
1393                         } else
1394                                 fprintf(stderr, "Could not run %s\n",
1395                                     _PATH_SSH_USER_RC);
1396                 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1397                         if (debug_flag)
1398                                 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1399                                     _PATH_SSH_SYSTEM_RC);
1400                         f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1401                         if (f) {
1402                                 if (do_xauth)
1403                                         fprintf(f, "%s %s\n", s->auth_proto,
1404                                             s->auth_data);
1405                                 pclose(f);
1406                         } else
1407                                 fprintf(stderr, "Could not run %s\n",
1408                                     _PATH_SSH_SYSTEM_RC);
1409                 } else if (do_xauth && options.xauth_location != NULL) {
1410                         /* Add authority data to .Xauthority if appropriate. */
1411                         char *screen = strchr(s->display, ':');
1412
1413                         if (debug_flag) {
1414                                 fprintf(stderr,
1415                                     "Running %.100s add "
1416                                     "%.100s %.100s %.100s\n",
1417                                     options.xauth_location, s->display,
1418                                     s->auth_proto, s->auth_data);
1419                                 if (screen != NULL)
1420                                         fprintf(stderr,
1421                                             "Adding %.*s/unix%s %s %s\n",
1422                                             (int)(screen - s->display),
1423                                             s->display, screen,
1424                                             s->auth_proto, s->auth_data);
1425                         }
1426                         snprintf(cmd, sizeof cmd, "%s -q -",
1427                             options.xauth_location);
1428                         f = popen(cmd, "w");
1429                         if (f) {
1430                                 fprintf(f, "add %s %s %s\n", s->display,
1431                                     s->auth_proto, s->auth_data);
1432                                 if (screen != NULL)
1433                                         fprintf(f, "add %.*s/unix%s %s %s\n",
1434                                             (int)(screen - s->display),
1435                                             s->display, screen,
1436                                             s->auth_proto,
1437                                             s->auth_data);
1438                                 pclose(f);
1439                         } else {
1440                                 fprintf(stderr, "Could not run %s\n",
1441                                     cmd);
1442                         }
1443                 }
1444                 /* Get the last component of the shell name. */
1445                 cp = strrchr(shell, '/');
1446                 if (cp)
1447                         cp++;
1448                 else
1449                         cp = shell;
1450         }
1451
1452         /* restore SIGPIPE for child */
1453         signal(SIGPIPE,  SIG_DFL);
1454
1455         /*
1456          * If we have no command, execute the shell.  In this case, the shell
1457          * name to be passed in argv[0] is preceded by '-' to indicate that
1458          * this is a login shell.
1459          */
1460         if (!command) {
1461                 if (!options.use_login) {
1462                         char buf[256];
1463
1464                         /* Start the shell.  Set initial character to '-'. */
1465                         buf[0] = '-';
1466                         strncpy(buf + 1, cp, sizeof(buf) - 1);
1467                         buf[sizeof(buf) - 1] = 0;
1468
1469                         /* Execute the shell. */
1470                         argv[0] = buf;
1471                         argv[1] = NULL;
1472                         execve(shell, argv, env);
1473
1474                         /* Executing the shell failed. */
1475                         perror(shell);
1476                         exit(1);
1477
1478                 } else {
1479                         /* Launch login(1). */
1480
1481                         execl(LOGIN_PROGRAM, "login", "-h", hostname,
1482 #ifdef LOGIN_NEEDS_TERM
1483                              s->term? s->term : "unknown",
1484 #endif
1485                              "-p", "-f", "--", pw->pw_name, (char *)NULL);
1486
1487                         /* Login couldn't be executed, die. */
1488
1489                         perror("login");
1490                         exit(1);
1491                 }
1492         }
1493         /*
1494          * Execute the command using the user's shell.  This uses the -c
1495          * option to execute the command.
1496          */
1497         argv[0] = (char *) cp;
1498         argv[1] = "-c";
1499         argv[2] = (char *) command;
1500         argv[3] = NULL;
1501         execve(shell, argv, env);
1502         perror(shell);
1503         exit(1);
1504 }
1505
1506 Session *
1507 session_new(void)
1508 {
1509         int i;
1510         static int did_init = 0;
1511         if (!did_init) {
1512                 debug("session_new: init");
1513                 for(i = 0; i < MAX_SESSIONS; i++) {
1514                         sessions[i].used = 0;
1515                 }
1516                 did_init = 1;
1517         }
1518         for(i = 0; i < MAX_SESSIONS; i++) {
1519                 Session *s = &sessions[i];
1520                 if (! s->used) {
1521                         memset(s, 0, sizeof(*s));
1522                         s->chanid = -1;
1523                         s->ptyfd = -1;
1524                         s->ttyfd = -1;
1525                         s->used = 1;
1526                         s->self = i;
1527                         debug("session_new: session %d", i);
1528                         return s;
1529                 }
1530         }
1531         return NULL;
1532 }
1533
1534 static void
1535 session_dump(void)
1536 {
1537         int i;
1538         for(i = 0; i < MAX_SESSIONS; i++) {
1539                 Session *s = &sessions[i];
1540                 debug("dump: used %d session %d %p channel %d pid %d",
1541                     s->used,
1542                     s->self,
1543                     s,
1544                     s->chanid,
1545                     s->pid);
1546         }
1547 }
1548
1549 int
1550 session_open(Authctxt *authctxt, int chanid)
1551 {
1552         Session *s = session_new();
1553         debug("session_open: channel %d", chanid);
1554         if (s == NULL) {
1555                 error("no more sessions");
1556                 return 0;
1557         }
1558         s->authctxt = authctxt;
1559         s->pw = authctxt->pw;
1560         if (s->pw == NULL)
1561                 fatal("no user for session %d", s->self);
1562         debug("session_open: session %d: link with channel %d", s->self, chanid);
1563         s->chanid = chanid;
1564         return 1;
1565 }
1566
1567 static Session *
1568 session_by_channel(int id)
1569 {
1570         int i;
1571         for(i = 0; i < MAX_SESSIONS; i++) {
1572                 Session *s = &sessions[i];
1573                 if (s->used && s->chanid == id) {
1574                         debug("session_by_channel: session %d channel %d", i, id);
1575                         return s;
1576                 }
1577         }
1578         debug("session_by_channel: unknown channel %d", id);
1579         session_dump();
1580         return NULL;
1581 }
1582
1583 static Session *
1584 session_by_pid(pid_t pid)
1585 {
1586         int i;
1587         debug("session_by_pid: pid %d", pid);
1588         for(i = 0; i < MAX_SESSIONS; i++) {
1589                 Session *s = &sessions[i];
1590                 if (s->used && s->pid == pid)
1591                         return s;
1592         }
1593         error("session_by_pid: unknown pid %d", pid);
1594         session_dump();
1595         return NULL;
1596 }
1597
1598 static int
1599 session_window_change_req(Session *s)
1600 {
1601         s->col = packet_get_int();
1602         s->row = packet_get_int();
1603         s->xpixel = packet_get_int();
1604         s->ypixel = packet_get_int();
1605         packet_done();
1606         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1607         return 1;
1608 }
1609
1610 static int
1611 session_pty_req(Session *s)
1612 {
1613         u_int len;
1614         int n_bytes;
1615
1616         if (no_pty_flag) {
1617                 debug("Allocating a pty not permitted for this authentication.");
1618                 return 0;
1619         }
1620         if (s->ttyfd != -1) {
1621                 packet_disconnect("Protocol error: you already have a pty.");
1622                 return 0;
1623         }
1624
1625         s->term = packet_get_string(&len);
1626
1627         if (compat20) {
1628                 s->col = packet_get_int();
1629                 s->row = packet_get_int();
1630         } else {
1631                 s->row = packet_get_int();
1632                 s->col = packet_get_int();
1633         }
1634         s->xpixel = packet_get_int();
1635         s->ypixel = packet_get_int();
1636
1637         if (strcmp(s->term, "") == 0) {
1638                 xfree(s->term);
1639                 s->term = NULL;
1640         }
1641
1642         /* Allocate a pty and open it. */
1643         debug("Allocating pty.");
1644         if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1645                 if (s->term)
1646                         xfree(s->term);
1647                 s->term = NULL;
1648                 s->ptyfd = -1;
1649                 s->ttyfd = -1;
1650                 error("session_pty_req: session %d alloc failed", s->self);
1651                 return 0;
1652         }
1653         debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1654
1655         /* for SSH1 the tty modes length is not given */
1656         if (!compat20)
1657                 n_bytes = packet_remaining();
1658         tty_parse_modes(s->ttyfd, &n_bytes);
1659
1660         /*
1661          * Add a cleanup function to clear the utmp entry and record logout
1662          * time in case we call fatal() (e.g., the connection gets closed).
1663          */
1664         fatal_add_cleanup(session_pty_cleanup, (void *)s);
1665         pty_setowner(s->pw, s->tty);
1666
1667         /* Set window size from the packet. */
1668         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1669
1670         packet_done();
1671         session_proctitle(s);
1672         return 1;
1673 }
1674
1675 static int
1676 session_subsystem_req(Session *s)
1677 {
1678         struct stat st;
1679         u_int len;
1680         int success = 0;
1681         char *cmd, *subsys = packet_get_string(&len);
1682         int i;
1683
1684         packet_done();
1685         log("subsystem request for %s", subsys);
1686
1687         for (i = 0; i < options.num_subsystems; i++) {
1688                 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1689                         cmd = options.subsystem_command[i];
1690                         if (stat(cmd, &st) < 0) {
1691                                 error("subsystem: cannot stat %s: %s", cmd,
1692                                     strerror(errno));
1693                                 break;
1694                         }
1695                         debug("subsystem: exec() %s", cmd);
1696                         s->is_subsystem = 1;
1697                         do_exec(s, cmd);
1698                         success = 1;
1699                 }
1700         }
1701
1702         if (!success)
1703                 log("subsystem request for %s failed, subsystem not found",
1704                     subsys);
1705
1706         xfree(subsys);
1707         return success;
1708 }
1709
1710 static int
1711 session_x11_req(Session *s)
1712 {
1713         int success;
1714
1715         s->single_connection = packet_get_char();
1716         s->auth_proto = packet_get_string(NULL);
1717         s->auth_data = packet_get_string(NULL);
1718         s->screen = packet_get_int();
1719         packet_done();
1720
1721         success = session_setup_x11fwd(s);
1722         if (!success) {
1723                 xfree(s->auth_proto);
1724                 xfree(s->auth_data);
1725                 s->auth_proto = NULL;
1726                 s->auth_data = NULL;
1727         }
1728         return success;
1729 }
1730
1731 static int
1732 session_shell_req(Session *s)
1733 {
1734         packet_done();
1735         do_exec(s, NULL);
1736         return 1;
1737 }
1738
1739 static int
1740 session_exec_req(Session *s)
1741 {
1742         u_int len;
1743         char *command = packet_get_string(&len);
1744         packet_done();
1745         do_exec(s, command);
1746         xfree(command);
1747         return 1;
1748 }
1749
1750 static int
1751 session_auth_agent_req(Session *s)
1752 {
1753         static int called = 0;
1754         packet_done();
1755         if (no_agent_forwarding_flag) {
1756                 debug("session_auth_agent_req: no_agent_forwarding_flag");
1757                 return 0;
1758         }
1759         if (called) {
1760                 return 0;
1761         } else {
1762                 called = 1;
1763                 return auth_input_request_forwarding(s->pw);
1764         }
1765 }
1766
1767 void
1768 session_input_channel_req(int id, void *arg)
1769 {
1770         u_int len;
1771         int reply;
1772         int success = 0;
1773         char *rtype;
1774         Session *s;
1775         Channel *c;
1776
1777         rtype = packet_get_string(&len);
1778         reply = packet_get_char();
1779
1780         s = session_by_channel(id);
1781         if (s == NULL)
1782                 fatal("session_input_channel_req: channel %d: no session", id);
1783         c = channel_lookup(id);
1784         if (c == NULL)
1785                 fatal("session_input_channel_req: channel %d: bad channel", id);
1786
1787         debug("session_input_channel_req: session %d channel %d request %s reply %d",
1788             s->self, id, rtype, reply);
1789
1790         /*
1791          * a session is in LARVAL state until a shell, a command
1792          * or a subsystem is executed
1793          */
1794         if (c->type == SSH_CHANNEL_LARVAL) {
1795                 if (strcmp(rtype, "shell") == 0) {
1796                         success = session_shell_req(s);
1797                 } else if (strcmp(rtype, "exec") == 0) {
1798                         success = session_exec_req(s);
1799                 } else if (strcmp(rtype, "pty-req") == 0) {
1800                         success =  session_pty_req(s);
1801                 } else if (strcmp(rtype, "x11-req") == 0) {
1802                         success = session_x11_req(s);
1803                 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1804                         success = session_auth_agent_req(s);
1805                 } else if (strcmp(rtype, "subsystem") == 0) {
1806                         success = session_subsystem_req(s);
1807                 }
1808         }
1809         if (strcmp(rtype, "window-change") == 0) {
1810                 success = session_window_change_req(s);
1811         }
1812
1813         if (reply) {
1814                 packet_start(success ?
1815                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1816                 packet_put_int(c->remote_id);
1817                 packet_send();
1818         }
1819         xfree(rtype);
1820 }
1821
1822 void
1823 session_set_fds(Session *s, int fdin, int fdout, int fderr)
1824 {
1825         if (!compat20)
1826                 fatal("session_set_fds: called for proto != 2.0");
1827         /*
1828          * now that have a child and a pipe to the child,
1829          * we can activate our channel and register the fd's
1830          */
1831         if (s->chanid == -1)
1832                 fatal("no channel for session %d", s->self);
1833         channel_set_fds(s->chanid,
1834             fdout, fdin, fderr,
1835             fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1836             1);
1837 }
1838
1839 /*
1840  * Function to perform pty cleanup. Also called if we get aborted abnormally
1841  * (e.g., due to a dropped connection).
1842  */
1843 static void
1844 session_pty_cleanup(void *session)
1845 {
1846         Session *s = session;
1847
1848         if (s == NULL) {
1849                 error("session_pty_cleanup: no session");
1850                 return;
1851         }
1852         if (s->ttyfd == -1)
1853                 return;
1854
1855         debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1856
1857         /* Record that the user has logged out. */
1858         if (s->pid != 0)
1859                 record_logout(s->pid, s->tty);
1860
1861         /* Release the pseudo-tty. */
1862         pty_release(s->tty);
1863
1864         /*
1865          * Close the server side of the socket pairs.  We must do this after
1866          * the pty cleanup, so that another process doesn't get this pty
1867          * while we're still cleaning up.
1868          */
1869         if (close(s->ptymaster) < 0)
1870                 error("close(s->ptymaster): %s", strerror(errno));
1871
1872         /* unlink pty from session */
1873         s->ttyfd = -1;
1874 }
1875
1876 static void
1877 session_exit_message(Session *s, int status)
1878 {
1879         Channel *c;
1880         if (s == NULL)
1881                 fatal("session_close: no session");
1882         c = channel_lookup(s->chanid);
1883         if (c == NULL)
1884                 fatal("session_exit_message: session %d: no channel %d",
1885                     s->self, s->chanid);
1886         debug("session_exit_message: session %d channel %d pid %d",
1887             s->self, s->chanid, s->pid);
1888
1889         if (WIFEXITED(status)) {
1890                 channel_request_start(s->chanid,
1891                     "exit-status", 0);
1892                 packet_put_int(WEXITSTATUS(status));
1893                 packet_send();
1894         } else if (WIFSIGNALED(status)) {
1895                 channel_request_start(s->chanid,
1896                     "exit-signal", 0);
1897                 packet_put_int(WTERMSIG(status));
1898 #ifdef WCOREDUMP
1899                 packet_put_char(WCOREDUMP(status));
1900 #else /* WCOREDUMP */
1901                 packet_put_char(0);
1902 #endif /* WCOREDUMP */
1903                 packet_put_cstring("");
1904                 packet_put_cstring("");
1905                 packet_send();
1906         } else {
1907                 /* Some weird exit cause.  Just exit. */
1908                 packet_disconnect("wait returned status %04x.", status);
1909         }
1910
1911         /* disconnect channel */
1912         debug("session_exit_message: release channel %d", s->chanid);
1913         channel_cancel_cleanup(s->chanid);
1914         /*
1915          * emulate a write failure with 'chan_write_failed', nobody will be
1916          * interested in data we write.
1917          * Note that we must not call 'chan_read_failed', since there could
1918          * be some more data waiting in the pipe.
1919          */
1920         if (c->ostate != CHAN_OUTPUT_CLOSED)
1921                 chan_write_failed(c);
1922         s->chanid = -1;
1923 }
1924
1925 static void
1926 session_close(Session *s)
1927 {
1928         debug("session_close: session %d pid %d", s->self, s->pid);
1929         if (s->ttyfd != -1) {
1930                 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1931                 session_pty_cleanup(s);
1932         }
1933         if (s->term)
1934                 xfree(s->term);
1935         if (s->display)
1936                 xfree(s->display);
1937         if (s->auth_data)
1938                 xfree(s->auth_data);
1939         if (s->auth_proto)
1940                 xfree(s->auth_proto);
1941         s->used = 0;
1942         session_proctitle(s);
1943 }
1944
1945 void
1946 session_close_by_pid(pid_t pid, int status)
1947 {
1948         Session *s = session_by_pid(pid);
1949         if (s == NULL) {
1950                 debug("session_close_by_pid: no session for pid %d", pid);
1951                 return;
1952         }
1953         if (s->chanid != -1)
1954                 session_exit_message(s, status);
1955         session_close(s);
1956 }
1957
1958 /*
1959  * this is called when a channel dies before
1960  * the session 'child' itself dies
1961  */
1962 void
1963 session_close_by_channel(int id, void *arg)
1964 {
1965         Session *s = session_by_channel(id);
1966         if (s == NULL) {
1967                 debug("session_close_by_channel: no session for id %d", id);
1968                 return;
1969         }
1970         debug("session_close_by_channel: channel %d child %d", id, s->pid);
1971         if (s->pid != 0) {
1972                 debug("session_close_by_channel: channel %d: has child", id);
1973                 /*
1974                  * delay detach of session, but release pty, since
1975                  * the fd's to the child are already closed
1976                  */
1977                 if (s->ttyfd != -1) {
1978                         fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1979                         session_pty_cleanup(s);
1980                 }
1981                 return;
1982         }
1983         /* detach by removing callback */
1984         channel_cancel_cleanup(s->chanid);
1985         s->chanid = -1;
1986         session_close(s);
1987 }
1988
1989 void
1990 session_destroy_all(void)
1991 {
1992         int i;
1993         for(i = 0; i < MAX_SESSIONS; i++) {
1994                 Session *s = &sessions[i];
1995                 if (s->used)
1996                         session_close(s);
1997         }
1998 }
1999
2000 static char *
2001 session_tty_list(void)
2002 {
2003         static char buf[1024];
2004         int i;
2005         buf[0] = '\0';
2006         for(i = 0; i < MAX_SESSIONS; i++) {
2007                 Session *s = &sessions[i];
2008                 if (s->used && s->ttyfd != -1) {
2009                         if (buf[0] != '\0')
2010                                 strlcat(buf, ",", sizeof buf);
2011                         strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2012                 }
2013         }
2014         if (buf[0] == '\0')
2015                 strlcpy(buf, "notty", sizeof buf);
2016         return buf;
2017 }
2018
2019 void
2020 session_proctitle(Session *s)
2021 {
2022         if (s->pw == NULL)
2023                 error("no user for session %d", s->self);
2024         else
2025                 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2026 }
2027
2028 int
2029 session_setup_x11fwd(Session *s)
2030 {
2031         struct stat st;
2032
2033         if (no_x11_forwarding_flag) {
2034                 packet_send_debug("X11 forwarding disabled in user configuration file.");
2035                 return 0;
2036         }
2037         if (!options.x11_forwarding) {
2038                 debug("X11 forwarding disabled in server configuration file.");
2039                 return 0;
2040         }
2041         if (!options.xauth_location ||
2042             (stat(options.xauth_location, &st) == -1)) {
2043                 packet_send_debug("No xauth program; cannot forward with spoofing.");
2044                 return 0;
2045         }
2046         if (options.use_login) {
2047                 packet_send_debug("X11 forwarding disabled; "
2048                     "not compatible with UseLogin=yes.");
2049                 return 0;
2050         }
2051         if (s->display != NULL) {
2052                 debug("X11 display already set.");
2053                 return 0;
2054         }
2055         s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
2056         if (s->display == NULL) {
2057                 debug("x11_create_display_inet failed.");
2058                 return 0;
2059         }
2060         return 1;
2061 }
2062
2063 static void
2064 do_authenticated2(Authctxt *authctxt)
2065 {
2066         server_loop2(authctxt);
2067 }