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 1.107 2001/10/10 22:18:47 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 #endif /* USE_PAM */
 436
 437         /* Fork the child. */
 438         if ((pid = fork()) == 0) {
 439                 /* Child.  Reinitialize the log since the pid has changed. */
 440                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 441
 442                 /*
 443                  * Create a new session and process group since the 4.4BSD
 444                  * setlogin() affects the entire process group.
 445                  */
 446                 if (setsid() < 0)
 447                         error("setsid failed: %.100s", strerror(errno));
 448
 449 #ifdef USE_PIPES
 450                 /*
 451                  * Redirect stdin.  We close the parent side of the socket
 452                  * pair, and make the child side the standard input.
 453                  */
 454                 close(pin[1]);
 455                 if (dup2(pin[0], 0) < 0)
 456                         perror("dup2 stdin");
 457                 close(pin[0]);
 458
 459                 /* Redirect stdout. */
 460                 close(pout[0]);
 461                 if (dup2(pout[1], 1) < 0)
 462                         perror("dup2 stdout");
 463                 close(pout[1]);
 464
 465                 /* Redirect stderr. */
 466                 close(perr[0]);
 467                 if (dup2(perr[1], 2) < 0)
 468                         perror("dup2 stderr");
 469                 close(perr[1]);
 470 #else /* USE_PIPES */
 471                 /*
 472                  * Redirect stdin, stdout, and stderr.  Stdin and stdout will
 473                  * use the same socket, as some programs (particularly rdist)
 474                  * seem to depend on it.
 475                  */
 476                 close(inout[1]);
 477                 close(err[1]);
 478                 if (dup2(inout[0], 0) < 0)      /* stdin */
 479                         perror("dup2 stdin");
 480                 if (dup2(inout[0], 1) < 0)      /* stdout.  Note: same socket as stdin. */
 481                         perror("dup2 stdout");
 482                 if (dup2(err[0], 2) < 0)        /* stderr */
 483                         perror("dup2 stderr");
 484 #endif /* USE_PIPES */
 485
 486                 /* Do processing for the child (exec command etc). */
 487                 do_child(s, command);
 488                 /* NOTREACHED */
 489         }
 490 #ifdef HAVE_CYGWIN
 491         if (is_winnt)
 492                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 493 #endif
 494         if (pid < 0)
 495                 packet_disconnect("fork failed: %.100s", strerror(errno));
 496         s->pid = pid;
 497         /* Set interactive/non-interactive mode. */
 498         packet_set_interactive(s->display != NULL);
 499 #ifdef USE_PIPES
 500         /* We are the parent.  Close the child sides of the pipes. */
 501         close(pin[0]);
 502         close(pout[1]);
 503         close(perr[1]);
 504
 505         if (compat20) {
 506                 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
 507         } else {
 508                 /* Enter the interactive session. */
 509                 server_loop(pid, pin[1], pout[0], perr[0]);
 510                 /* server_loop has closed pin[1], pout[0], and perr[0]. */
 511         }
 512 #else /* USE_PIPES */
 513         /* We are the parent.  Close the child sides of the socket pairs. */
 514         close(inout[0]);
 515         close(err[0]);
 516
 517         /*
 518          * Enter the interactive session.  Note: server_loop must be able to
 519          * handle the case that fdin and fdout are the same.
 520          */
 521         if (compat20) {
 522                 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
 523         } else {
 524                 server_loop(pid, inout[1], inout[1], err[1]);
 525                 /* server_loop has closed inout[1] and err[1]. */
 526         }
 527 #endif /* USE_PIPES */
 528 }
 529
 530 /*
 531  * This is called to fork and execute a command when we have a tty.  This
 532  * will call do_child from the child, and server_loop from the parent after
 533  * setting up file descriptors, controlling tty, updating wtmp, utmp,
 534  * lastlog, and other such operations.
 535  */
 536 void
 537 do_exec_pty(Session *s, const char *command)
 538 {
 539         int fdout, ptyfd, ttyfd, ptymaster;
 540         pid_t pid;
 541
 542         if (s == NULL)
 543                 fatal("do_exec_pty: no session");
 544         ptyfd = s->ptyfd;
 545         ttyfd = s->ttyfd;
 546
 547 #if defined(USE_PAM)
 548         do_pam_session(s->pw->pw_name, s->tty);
 549         do_pam_setcred(1);
 550 #endif
 551
 552         /* Fork the child. */
 553         if ((pid = fork()) == 0) {
 554
 555                 /* Child.  Reinitialize the log because the pid has changed. */
 556                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 557                 /* Close the master side of the pseudo tty. */
 558                 close(ptyfd);
 559
 560                 /* Make the pseudo tty our controlling tty. */
 561                 pty_make_controlling_tty(&ttyfd, s->tty);
 562
 563                 /* Redirect stdin/stdout/stderr from the pseudo tty. */
 564                 if (dup2(ttyfd, 0) < 0)
 565                         error("dup2 stdin: %s", strerror(errno));
 566                 if (dup2(ttyfd, 1) < 0)
 567                         error("dup2 stdout: %s", strerror(errno));
 568                 if (dup2(ttyfd, 2) < 0)
 569                         error("dup2 stderr: %s", strerror(errno));
 570
 571                 /* Close the extra descriptor for the pseudo tty. */
 572                 close(ttyfd);
 573
 574                 /* record login, etc. similar to login(1) */
 575 #ifndef HAVE_OSF_SIA
 576                 if (!(options.use_login && command == NULL))
 577                         do_login(s, command);
 578 # ifdef LOGIN_NEEDS_UTMPX
 579                 else
 580                         do_pre_login(s);
 581 # endif
 582 #endif
 583
 584                 /* Do common processing for the child, such as execing the command. */
 585                 do_child(s, command);
 586                 /* NOTREACHED */
 587         }
 588 #ifdef HAVE_CYGWIN
 589         if (is_winnt)
 590                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 591 #endif
 592         if (pid < 0)
 593                 packet_disconnect("fork failed: %.100s", strerror(errno));
 594         s->pid = pid;
 595
 596         /* Parent.  Close the slave side of the pseudo tty. */
 597         close(ttyfd);
 598
 599         /*
 600          * Create another descriptor of the pty master side for use as the
 601          * standard input.  We could use the original descriptor, but this
 602          * simplifies code in server_loop.  The descriptor is bidirectional.
 603          */
 604         fdout = dup(ptyfd);
 605         if (fdout < 0)
 606                 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
 607
 608         /* we keep a reference to the pty master */
 609         ptymaster = dup(ptyfd);
 610         if (ptymaster < 0)
 611                 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
 612         s->ptymaster = ptymaster;
 613
 614         /* Enter interactive session. */
 615         packet_set_interactive(1);
 616         if (compat20) {
 617                 session_set_fds(s, ptyfd, fdout, -1);
 618         } else {
 619                 server_loop(pid, ptyfd, fdout, -1);
 620                 /* server_loop _has_ closed ptyfd and fdout. */
 621         }
 622 }
 623
 624 #ifdef LOGIN_NEEDS_UTMPX
 625 static void
 626 do_pre_login(Session *s)
 627 {
 628         socklen_t fromlen;
 629         struct sockaddr_storage from;
 630         pid_t pid = getpid();
 631
 632         /*
 633          * Get IP address of client. If the connection is not a socket, let
 634          * the address be 0.0.0.0.
 635          */
 636         memset(&from, 0, sizeof(from));
 637         if (packet_connection_is_on_socket()) {
 638                 fromlen = sizeof(from);
 639                 if (getpeername(packet_get_connection_in(),
 640                      (struct sockaddr *) & from, &fromlen) < 0) {
 641                         debug("getpeername: %.100s", strerror(errno));
 642                         fatal_cleanup();
 643                 }
 644         }
 645
 646         record_utmp_only(pid, s->tty, s->pw->pw_name,
 647             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 648             (struct sockaddr *)&from);
 649 }
 650 #endif
 651
 652 /*
 653  * This is called to fork and execute a command.  If another command is
 654  * to be forced, execute that instead.
 655  */
 656 void
 657 do_exec(Session *s, const char *command)
 658 {
 659         if (forced_command) {
 660                 original_command = command;
 661                 command = forced_command;
 662                 debug("Forced command '%.900s'", command);
 663         }
 664
 665         if (s->ttyfd != -1)
 666                 do_exec_pty(s, command);
 667         else
 668                 do_exec_no_pty(s, command);
 669
 670         original_command = NULL;
 671 }
 672
 673 /* administrative, login(1)-like work */
 674 void
 675 do_login(Session *s, const char *command)
 676 {
 677         char *time_string;
 678         char hostname[MAXHOSTNAMELEN];
 679         socklen_t fromlen;
 680         struct sockaddr_storage from;
 681         time_t last_login_time;
 682         struct passwd * pw = s->pw;
 683         pid_t pid = getpid();
 684
 685         /*
 686          * Get IP address of client. If the connection is not a socket, let
 687          * the address be 0.0.0.0.
 688          */
 689         memset(&from, 0, sizeof(from));
 690         if (packet_connection_is_on_socket()) {
 691                 fromlen = sizeof(from);
 692                 if (getpeername(packet_get_connection_in(),
 693                      (struct sockaddr *) & from, &fromlen) < 0) {
 694                         debug("getpeername: %.100s", strerror(errno));
 695                         fatal_cleanup();
 696                 }
 697         }
 698
 699         /* Get the time and hostname when the user last logged in. */
 700         if (options.print_lastlog) {
 701                 hostname[0] = '\0';
 702                 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
 703                     hostname, sizeof(hostname));
 704         }
 705
 706         /* Record that there was a login on that tty from the remote host. */
 707         record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
 708             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 709             (struct sockaddr *)&from);
 710
 711 #ifdef USE_PAM
 712         /*
 713          * If password change is needed, do it now.
 714          * This needs to occur before the ~/.hushlogin check.
 715          */
 716         if (is_pam_password_change_required()) {
 717                 print_pam_messages();
 718                 do_pam_chauthtok();
 719         }
 720 #endif
 721
 722         if (check_quietlogin(s, command))
 723                 return;
 724
 725 #ifdef USE_PAM
 726         if (!is_pam_password_change_required())
 727                 print_pam_messages();
 728 #endif /* USE_PAM */
 729 #ifdef WITH_AIXAUTHENTICATE
 730         if (aixloginmsg && *aixloginmsg)
 731                 printf("%s\n", aixloginmsg);
 732 #endif /* WITH_AIXAUTHENTICATE */
 733
 734         if (options.print_lastlog && last_login_time != 0) {
 735                 time_string = ctime(&last_login_time);
 736                 if (strchr(time_string, '\n'))
 737                         *strchr(time_string, '\n') = 0;
 738                 if (strcmp(hostname, "") == 0)
 739                         printf("Last login: %s\r\n", time_string);
 740                 else
 741                         printf("Last login: %s from %s\r\n", time_string, hostname);
 742         }
 743
 744         do_motd();
 745 }
 746
 747 /*
 748  * Display the message of the day.
 749  */
 750 void
 751 do_motd(void)
 752 {
 753         FILE *f;
 754         char buf[256];
 755
 756         if (options.print_motd) {
 757 #ifdef HAVE_LOGIN_CAP
 758                 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
 759                     "/etc/motd"), "r");
 760 #else
 761                 f = fopen("/etc/motd", "r");
 762 #endif
 763                 if (f) {
 764                         while (fgets(buf, sizeof(buf), f))
 765                                 fputs(buf, stdout);
 766                         fclose(f);
 767                 }
 768         }
 769 }
 770
 771
 772 /*
 773  * Check for quiet login, either .hushlogin or command given.
 774  */
 775 int
 776 check_quietlogin(Session *s, const char *command)
 777 {
 778         char buf[256];
 779         struct passwd *pw = s->pw;
 780         struct stat st;
 781
 782         /* Return 1 if .hushlogin exists or a command given. */
 783         if (command != NULL)
 784                 return 1;
 785         snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
 786 #ifdef HAVE_LOGIN_CAP
 787         if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
 788                 return 1;
 789 #else
 790         if (stat(buf, &st) >= 0)
 791                 return 1;
 792 #endif
 793         return 0;
 794 }
 795
 796 /*
 797  * Sets the value of the given variable in the environment.  If the variable
 798  * already exists, its value is overriden.
 799  */
 800 static void
 801 child_set_env(char ***envp, u_int *envsizep, const char *name,
 802               const char *value)
 803 {
 804         u_int i, namelen;
 805         char **env;
 806
 807         /*
 808          * Find the slot where the value should be stored.  If the variable
 809          * already exists, we reuse the slot; otherwise we append a new slot
 810          * at the end of the array, expanding if necessary.
 811          */
 812         env = *envp;
 813         namelen = strlen(name);
 814         for (i = 0; env[i]; i++)
 815                 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
 816                         break;
 817         if (env[i]) {
 818                 /* Reuse the slot. */
 819                 xfree(env[i]);
 820         } else {
 821                 /* New variable.  Expand if necessary. */
 822                 if (i >= (*envsizep) - 1) {
 823                         (*envsizep) += 50;
 824                         env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
 825                 }
 826                 /* Need to set the NULL pointer at end of array beyond the new slot. */
 827                 env[i + 1] = NULL;
 828         }
 829
 830         /* Allocate space and format the variable in the appropriate slot. */
 831         env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
 832         snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
 833 }
 834
 835 /*
 836  * Reads environment variables from the given file and adds/overrides them
 837  * into the environment.  If the file does not exist, this does nothing.
 838  * Otherwise, it must consist of empty lines, comments (line starts with '#')
 839  * and assignments of the form name=value.  No other forms are allowed.
 840  */
 841 static void
 842 read_environment_file(char ***env, u_int *envsize,
 843                       const char *filename)
 844 {
 845         FILE *f;
 846         char buf[4096];
 847         char *cp, *value;
 848
 849         f = fopen(filename, "r");
 850         if (!f)
 851                 return;
 852
 853         while (fgets(buf, sizeof(buf), f)) {
 854                 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
 855                         ;
 856                 if (!*cp || *cp == '#' || *cp == '\n')
 857                         continue;
 858                 if (strchr(cp, '\n'))
 859                         *strchr(cp, '\n') = '\0';
 860                 value = strchr(cp, '=');
 861                 if (value == NULL) {
 862                         fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
 863                         continue;
 864                 }
 865                 /*
 866                  * Replace the equals sign by nul, and advance value to
 867                  * the value string.
 868                  */
 869                 *value = '\0';
 870                 value++;
 871                 child_set_env(env, envsize, cp, value);
 872         }
 873         fclose(f);
 874 }
 875
 876 #ifdef USE_PAM
 877 /*
 878  * Sets any environment variables which have been specified by PAM
 879  */
 880 void do_pam_environment(char ***env, u_int *envsize)
 881 {
 882         char *equals, var_name[512], var_val[512];
 883         char **pam_env;
 884         int i;
 885
 886         if ((pam_env = fetch_pam_environment()) == NULL)
 887                 return;
 888
 889         for(i = 0; pam_env[i] != NULL; i++) {
 890                 if ((equals = strstr(pam_env[i], "=")) == NULL)
 891                         continue;
 892
 893                 if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) {
 894                         memset(var_name, '\0', sizeof(var_name));
 895                         memset(var_val, '\0', sizeof(var_val));
 896
 897                         strncpy(var_name, pam_env[i], equals - pam_env[i]);
 898                         strcpy(var_val, equals + 1);
 899
 900                         debug3("PAM environment: %s=%s", var_name, var_val);
 901
 902                         child_set_env(env, envsize, var_name, var_val);
 903                 }
 904         }
 905 }
 906 #endif /* USE_PAM */
 907
 908 #ifdef HAVE_CYGWIN
 909 void copy_environment(char ***env, u_int *envsize)
 910 {
 911         char *equals, var_name[512], var_val[512];
 912         int i;
 913
 914         for(i = 0; environ[i] != NULL; i++) {
 915                 if ((equals = strstr(environ[i], "=")) == NULL)
 916                         continue;
 917
 918                 if (strlen(environ[i]) < (sizeof(var_name) - 1)) {
 919                         memset(var_name, '\0', sizeof(var_name));
 920                         memset(var_val, '\0', sizeof(var_val));
 921
 922                         strncpy(var_name, environ[i], equals - environ[i]);
 923                         strcpy(var_val, equals + 1);
 924
 925                         debug3("Copy environment: %s=%s", var_name, var_val);
 926
 927                         child_set_env(env, envsize, var_name, var_val);
 928                 }
 929         }
 930 }
 931 #endif
 932
 933 #if defined(HAVE_GETUSERATTR)
 934 /*
 935  * AIX-specific login initialisation
 936  */
 937 void set_limit(char *user, char *soft, char *hard, int resource, int mult)
 938 {
 939         struct rlimit rlim;
 940         int slim, hlim;
 941
 942         getrlimit(resource, &rlim);
 943
 944         slim = 0;
 945         if (getuserattr(user, soft, &slim, SEC_INT) != -1) {
 946                 if (slim < 0) {
 947                         rlim.rlim_cur = RLIM_INFINITY;
 948                 } else if (slim != 0) {
 949                         /* See the wackiness below */
 950                         if (rlim.rlim_cur == slim * mult)
 951                                 slim = 0;
 952                         else
 953                                 rlim.rlim_cur = slim * mult;
 954                 }
 955         }
 956
 957         hlim = 0;
 958         if (getuserattr(user, hard, &hlim, SEC_INT) != -1) {
 959                 if (hlim < 0) {
 960                         rlim.rlim_max = RLIM_INFINITY;
 961                 } else if (hlim != 0) {
 962                         rlim.rlim_max = hlim * mult;
 963                 }
 964         }
 965
 966         /*
 967          * XXX For cpu and fsize the soft limit is set to the hard limit
 968          * if the hard limit is left at its default value and the soft limit
 969          * is changed from its default value, either by requesting it
 970          * (slim == 0) or by setting it to the current default.  At least
 971          * that's how rlogind does it.  If you're confused you're not alone.
 972          * Bug or feature? AIX 4.3.1.2
 973          */
 974         if ((!strcmp(soft, "fsize") || !strcmp(soft, "cpu"))
 975             && hlim == 0 && slim != 0)
 976                 rlim.rlim_max = rlim.rlim_cur;
 977         /* A specified hard limit limits the soft limit */
 978         else if (hlim > 0 && rlim.rlim_cur > rlim.rlim_max)
 979                 rlim.rlim_cur = rlim.rlim_max;
 980         /* A soft limit can increase a hard limit */
 981         else if (rlim.rlim_cur > rlim.rlim_max)
 982                 rlim.rlim_max = rlim.rlim_cur;
 983
 984         if (setrlimit(resource, &rlim) != 0)
 985                 error("setrlimit(%.10s) failed: %.100s", soft, strerror(errno));
 986 }
 987
 988 void set_limits_from_userattr(char *user)
 989 {
 990         int mask;
 991         char buf[16];
 992
 993         set_limit(user, S_UFSIZE, S_UFSIZE_HARD, RLIMIT_FSIZE, 512);
 994         set_limit(user, S_UCPU, S_UCPU_HARD, RLIMIT_CPU, 1);
 995         set_limit(user, S_UDATA, S_UDATA_HARD, RLIMIT_DATA, 512);
 996         set_limit(user, S_USTACK, S_USTACK_HARD, RLIMIT_STACK, 512);
 997         set_limit(user, S_URSS, S_URSS_HARD, RLIMIT_RSS, 512);
 998         set_limit(user, S_UCORE, S_UCORE_HARD, RLIMIT_CORE, 512);
 999 #if defined(S_UNOFILE)
1000         set_limit(user, S_UNOFILE, S_UNOFILE_HARD, RLIMIT_NOFILE, 1);
1001 #endif
1002
1003         if (getuserattr(user, S_UMASK, &mask, SEC_INT) != -1) {
1004                 /* Convert decimal to octal */
1005                 (void) snprintf(buf, sizeof(buf), "%d", mask);
1006                 if (sscanf(buf, "%o", &mask) == 1)
1007                         umask(mask);
1008         }
1009 }
1010 #endif /* defined(HAVE_GETUSERATTR) */
1011
1012 /*
1013  * Performs common processing for the child, such as setting up the
1014  * environment, closing extra file descriptors, setting the user and group
1015  * ids, and executing the command or shell.
1016  */
1017 void
1018 do_child(Session *s, const char *command)
1019 {
1020         const char *shell, *hostname = NULL, *cp = NULL;
1021         struct passwd *pw = s->pw;
1022         char buf[256];
1023         char cmd[1024];
1024         FILE *f = NULL;
1025         u_int envsize, i;
1026         char **env;
1027         extern char **environ;
1028         struct stat st;
1029         char *argv[10];
1030         int do_xauth;
1031 #ifdef WITH_IRIX_PROJECT
1032         prid_t projid;
1033 #endif /* WITH_IRIX_PROJECT */
1034 #ifdef WITH_IRIX_JOBS
1035         jid_t jid = 0;
1036 #else
1037 #ifdef WITH_IRIX_ARRAY
1038         int jid = 0;
1039 #endif /* WITH_IRIX_ARRAY */
1040 #endif /* WITH_IRIX_JOBS */
1041
1042         do_xauth =
1043             s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1044
1045         /* remove hostkey from the child's memory */
1046         destroy_sensitive_data();
1047
1048         /* login(1) is only called if we execute the login shell */
1049         if (options.use_login && command != NULL)
1050                 options.use_login = 0;
1051
1052 #if !defined(HAVE_OSF_SIA)
1053         if (!options.use_login) {
1054 # ifdef HAVE_LOGIN_CAP
1055                 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1056                         f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1057                             _PATH_NOLOGIN), "r");
1058 # else /* HAVE_LOGIN_CAP */
1059                 if (pw->pw_uid)
1060                         f = fopen(_PATH_NOLOGIN, "r");
1061 # endif /* HAVE_LOGIN_CAP */
1062                 if (f) {
1063                         /* /etc/nologin exists.  Print its contents and exit. */
1064                         while (fgets(buf, sizeof(buf), f))
1065                                 fputs(buf, stderr);
1066                         fclose(f);
1067                         exit(254);
1068                 }
1069         }
1070 #endif /* HAVE_OSF_SIA */
1071
1072         /* Set login name, uid, gid, and groups. */
1073         /* Login(1) does this as well, and it needs uid 0 for the "-h"
1074            switch, so we let login(1) to this for us. */
1075         if (!options.use_login) {
1076 #ifdef HAVE_OSF_SIA
1077                 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1078                 if (!check_quietlogin(s, command))
1079                         do_motd();
1080 #else /* HAVE_OSF_SIA */
1081 #ifdef HAVE_CYGWIN
1082                 if (is_winnt) {
1083 #else
1084                 if (getuid() == 0 || geteuid() == 0) {
1085 #endif
1086 # ifdef HAVE_GETUSERATTR
1087                         set_limits_from_userattr(pw->pw_name);
1088 # endif /* HAVE_GETUSERATTR */
1089 # ifdef HAVE_LOGIN_CAP
1090                         if (setusercontext(lc, pw, pw->pw_uid,
1091                             (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1092                                 perror("unable to set user context");
1093                                 exit(1);
1094                         }
1095 # else /* HAVE_LOGIN_CAP */
1096 #if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1097                         /* Sets login uid for accounting */
1098                         if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1099                                 error("setluid: %s", strerror(errno));
1100 #endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1101
1102                         if (setlogin(pw->pw_name) < 0)
1103                                 error("setlogin failed: %s", strerror(errno));
1104                         if (setgid(pw->pw_gid) < 0) {
1105                                 perror("setgid");
1106                                 exit(1);
1107                         }
1108                         /* Initialize the group list. */
1109                         if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1110                                 perror("initgroups");
1111                                 exit(1);
1112                         }
1113                         endgrent();
1114 #  ifdef USE_PAM
1115                         /*
1116                          * PAM credentials may take the form of
1117                          * supplementary groups. These will have been
1118                          * wiped by the above initgroups() call.
1119                          * Reestablish them here.
1120                          */
1121                         do_pam_setcred(0);
1122 #  endif /* USE_PAM */
1123 #  ifdef WITH_IRIX_JOBS
1124                         jid = jlimit_startjob(pw->pw_name, pw->pw_uid, "interactive");
1125                         if (jid == -1) {
1126                                 fatal("Failed to create job container: %.100s",
1127                                       strerror(errno));
1128                         }
1129 #  endif /* WITH_IRIX_JOBS */
1130 #  ifdef WITH_IRIX_ARRAY
1131                         /* initialize array session */
1132                         if (jid == 0) {
1133                                 if (newarraysess() != 0)
1134                                         fatal("Failed to set up new array session: %.100s",
1135                                               strerror(errno));
1136                         }
1137 #  endif /* WITH_IRIX_ARRAY */
1138 #  ifdef WITH_IRIX_PROJECT
1139                         /* initialize irix project info */
1140                         if ((projid = getdfltprojuser(pw->pw_name)) == -1) {
1141                           debug("Failed to get project id, using projid 0");
1142                           projid = 0;
1143                         }
1144                         if (setprid(projid))
1145                           fatal("Failed to initialize project %d for %s: %.100s",
1146                                 (int)projid, pw->pw_name, strerror(errno));
1147 #  endif /* WITH_IRIX_PROJECT */
1148 #ifdef WITH_IRIX_AUDIT
1149                         if (sysconf(_SC_AUDIT)) {
1150                                 debug("Setting sat id to %d", (int) pw->pw_uid);
1151                                 if (satsetid(pw->pw_uid))
1152                                         debug("error setting satid: %.100s", strerror(errno));
1153                         }
1154 #endif /* WITH_IRIX_AUDIT */
1155
1156 #ifdef _AIX
1157                         /*
1158                          * AIX has a "usrinfo" area where logname and
1159                          * other stuff is stored - a few applications
1160                          * actually use this and die if it's not set
1161                          */
1162                         if (s->ttyfd == -1)
1163                                 s->tty[0] = '\0';
1164                         cp = xmalloc(22 + strlen(s->tty) +
1165                             2 * strlen(pw->pw_name));
1166                         i = sprintf(cp, "LOGNAME=%s%cNAME=%s%cTTY=%s%c%c",
1167                             pw->pw_name, 0, pw->pw_name, 0, s->tty, 0, 0);
1168                         if (usrinfo(SETUINFO, cp, i) == -1)
1169                                 fatal("Couldn't set usrinfo: %s",
1170                                     strerror(errno));
1171                         debug3("AIX/UsrInfo: set len %d", i);
1172                         xfree(cp);
1173 #endif
1174
1175                         /* Permanently switch to the desired uid. */
1176                         permanently_set_uid(pw);
1177 # endif /* HAVE_LOGIN_CAP */
1178                 }
1179 #endif /* HAVE_OSF_SIA */
1180
1181 #ifdef HAVE_CYGWIN
1182                 if (is_winnt)
1183 #endif
1184                 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1185                         fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1186         }
1187         /*
1188          * Get the shell from the password data.  An empty shell field is
1189          * legal, and means /bin/sh.
1190          */
1191         shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1192 #ifdef HAVE_LOGIN_CAP
1193         shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1194 #endif
1195
1196         /* Initialize the environment. */
1197         envsize = 100;
1198         env = xmalloc(envsize * sizeof(char *));
1199         env[0] = NULL;
1200
1201 #ifdef HAVE_CYGWIN
1202         /*
1203          * The Windows environment contains some setting which are
1204          * important for a running system. They must not be dropped.
1205          */
1206         copy_environment(&env, &envsize);
1207 #endif
1208
1209         if (!options.use_login) {
1210                 /* Set basic environment. */
1211                 child_set_env(&env, &envsize, "USER", pw->pw_name);
1212                 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1213                 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1214 #ifdef HAVE_LOGIN_CAP
1215                 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
1216                 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1217 #else /* HAVE_LOGIN_CAP */
1218 # ifndef HAVE_CYGWIN
1219                 /*
1220                  * There's no standard path on Windows. The path contains
1221                  * important components pointing to the system directories,
1222                  * needed for loading shared libraries. So the path better
1223                  * remains intact here.
1224                  */
1225                 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1226 # endif /* HAVE_CYGWIN */
1227 #endif /* HAVE_LOGIN_CAP */
1228
1229                 snprintf(buf, sizeof buf, "%.200s/%.50s",
1230                          _PATH_MAILDIR, pw->pw_name);
1231                 child_set_env(&env, &envsize, "MAIL", buf);
1232
1233                 /* Normal systems set SHELL by default. */
1234                 child_set_env(&env, &envsize, "SHELL", shell);
1235         }
1236         if (getenv("TZ"))
1237                 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1238
1239         /* Set custom environment options from RSA authentication. */
1240         while (custom_environment) {
1241                 struct envstring *ce = custom_environment;
1242                 char *s = ce->s;
1243                 int i;
1244                 for (i = 0; s[i] != '=' && s[i]; i++);
1245                 if (s[i] == '=') {
1246                         s[i] = 0;
1247                         child_set_env(&env, &envsize, s, s + i + 1);
1248                 }
1249                 custom_environment = ce->next;
1250                 xfree(ce->s);
1251                 xfree(ce);
1252         }
1253
1254         snprintf(buf, sizeof buf, "%.50s %d %d",
1255                  get_remote_ipaddr(), get_remote_port(), get_local_port());
1256         child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1257
1258         if (s->ttyfd != -1)
1259                 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1260         if (s->term)
1261                 child_set_env(&env, &envsize, "TERM", s->term);
1262         if (s->display)
1263                 child_set_env(&env, &envsize, "DISPLAY", s->display);
1264         if (original_command)
1265                 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1266                     original_command);
1267
1268 #ifdef _AIX
1269         if ((cp = getenv("AUTHSTATE")) != NULL)
1270                 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1271         if ((cp = getenv("KRB5CCNAME")) != NULL)
1272                 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1273         read_environment_file(&env, &envsize, "/etc/environment");
1274 #endif
1275 #ifdef KRB4
1276         if (s->authctxt->krb4_ticket_file)
1277                 child_set_env(&env, &envsize, "KRBTKFILE",
1278                     s->authctxt->krb4_ticket_file);
1279 #endif
1280 #ifdef KRB5
1281         if (s->authctxt->krb5_ticket_file)
1282                 child_set_env(&env, &envsize, "KRB5CCNAME",
1283                     s->authctxt->krb5_ticket_file);
1284 #endif
1285 #ifdef USE_PAM
1286         /* Pull in any environment variables that may have been set by PAM. */
1287         do_pam_environment(&env, &envsize);
1288 #endif /* USE_PAM */
1289
1290         if (auth_get_socket_name() != NULL)
1291                 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1292                               auth_get_socket_name());
1293
1294         /* read $HOME/.ssh/environment. */
1295         if (!options.use_login) {
1296                 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1297                     pw->pw_dir);
1298                 read_environment_file(&env, &envsize, buf);
1299         }
1300         if (debug_flag) {
1301                 /* dump the environment */
1302                 fprintf(stderr, "Environment:\n");
1303                 for (i = 0; env[i]; i++)
1304                         fprintf(stderr, "  %.200s\n", env[i]);
1305         }
1306         /* we have to stash the hostname before we close our socket. */
1307         if (options.use_login)
1308                 hostname = get_remote_name_or_ip(utmp_len,
1309                     options.reverse_mapping_check);
1310         /*
1311          * Close the connection descriptors; note that this is the child, and
1312          * the server will still have the socket open, and it is important
1313          * that we do not shutdown it.  Note that the descriptors cannot be
1314          * closed before building the environment, as we call
1315          * get_remote_ipaddr there.
1316          */
1317         if (packet_get_connection_in() == packet_get_connection_out())
1318                 close(packet_get_connection_in());
1319         else {
1320                 close(packet_get_connection_in());
1321                 close(packet_get_connection_out());
1322         }
1323         /*
1324          * Close all descriptors related to channels.  They will still remain
1325          * open in the parent.
1326          */
1327         /* XXX better use close-on-exec? -markus */
1328         channel_close_all();
1329
1330         /*
1331          * Close any extra file descriptors.  Note that there may still be
1332          * descriptors left by system functions.  They will be closed later.
1333          */
1334         endpwent();
1335
1336         /*
1337          * Close any extra open file descriptors so that we don\'t have them
1338          * hanging around in clients.  Note that we want to do this after
1339          * initgroups, because at least on Solaris 2.3 it leaves file
1340          * descriptors open.
1341          */
1342         for (i = 3; i < 64; i++)
1343                 close(i);
1344
1345         /*
1346          * Must take new environment into use so that .ssh/rc, /etc/sshrc and
1347          * xauth are run in the proper environment.
1348          */
1349         environ = env;
1350
1351 #ifdef AFS
1352         /* Try to get AFS tokens for the local cell. */
1353         if (k_hasafs()) {
1354                 char cell[64];
1355
1356                 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1357                         krb_afslog(cell, 0);
1358
1359                 krb_afslog(0, 0);
1360         }
1361 #endif /* AFS */
1362
1363         /* Change current directory to the user\'s home directory. */
1364         if (chdir(pw->pw_dir) < 0) {
1365                 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1366                     pw->pw_dir, strerror(errno));
1367 #ifdef HAVE_LOGIN_CAP
1368                 if (login_getcapbool(lc, "requirehome", 0))
1369                         exit(1);
1370 #endif
1371         }
1372
1373         /*
1374          * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
1375          * in this order).
1376          */
1377         if (!options.use_login) {
1378                 /* ignore _PATH_SSH_USER_RC for subsystems */
1379                 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1380                         snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1381                             shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1382                         if (debug_flag)
1383                                 fprintf(stderr, "Running %s\n", cmd);
1384                         f = popen(cmd, "w");
1385                         if (f) {
1386                                 if (do_xauth)
1387                                         fprintf(f, "%s %s\n", s->auth_proto,
1388                                             s->auth_data);
1389                                 pclose(f);
1390                         } else
1391                                 fprintf(stderr, "Could not run %s\n",
1392                                     _PATH_SSH_USER_RC);
1393                 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1394                         if (debug_flag)
1395                                 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1396                                     _PATH_SSH_SYSTEM_RC);
1397                         f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1398                         if (f) {
1399                                 if (do_xauth)
1400                                         fprintf(f, "%s %s\n", s->auth_proto,
1401                                             s->auth_data);
1402                                 pclose(f);
1403                         } else
1404                                 fprintf(stderr, "Could not run %s\n",
1405                                     _PATH_SSH_SYSTEM_RC);
1406                 } else if (do_xauth && options.xauth_location != NULL) {
1407                         /* Add authority data to .Xauthority if appropriate. */
1408                         char *screen = strchr(s->display, ':');
1409
1410                         if (debug_flag) {
1411                                 fprintf(stderr,
1412                                     "Running %.100s add "
1413                                     "%.100s %.100s %.100s\n",
1414                                     options.xauth_location, s->display,
1415                                     s->auth_proto, s->auth_data);
1416                                 if (screen != NULL)
1417                                         fprintf(stderr,
1418                                             "Adding %.*s/unix%s %s %s\n",
1419                                             (int)(screen - s->display),
1420                                             s->display, screen,
1421                                             s->auth_proto, s->auth_data);
1422                         }
1423                         snprintf(cmd, sizeof cmd, "%s -q -",
1424                             options.xauth_location);
1425                         f = popen(cmd, "w");
1426                         if (f) {
1427                                 fprintf(f, "add %s %s %s\n", s->display,
1428                                     s->auth_proto, s->auth_data);
1429                                 if (screen != NULL)
1430                                         fprintf(f, "add %.*s/unix%s %s %s\n",
1431                                             (int)(screen - s->display),
1432                                             s->display, screen,
1433                                             s->auth_proto,
1434                                             s->auth_data);
1435                                 pclose(f);
1436                         } else {
1437                                 fprintf(stderr, "Could not run %s\n",
1438                                     cmd);
1439                         }
1440                 }
1441                 /* Get the last component of the shell name. */
1442                 cp = strrchr(shell, '/');
1443                 if (cp)
1444                         cp++;
1445                 else
1446                         cp = shell;
1447         }
1448
1449         /* restore SIGPIPE for child */
1450         signal(SIGPIPE,  SIG_DFL);
1451
1452         /*
1453          * If we have no command, execute the shell.  In this case, the shell
1454          * name to be passed in argv[0] is preceded by '-' to indicate that
1455          * this is a login shell.
1456          */
1457         if (!command) {
1458                 if (!options.use_login) {
1459                         char buf[256];
1460
1461                         /* Start the shell.  Set initial character to '-'. */
1462                         buf[0] = '-';
1463                         strncpy(buf + 1, cp, sizeof(buf) - 1);
1464                         buf[sizeof(buf) - 1] = 0;
1465
1466                         /* Execute the shell. */
1467                         argv[0] = buf;
1468                         argv[1] = NULL;
1469                         execve(shell, argv, env);
1470
1471                         /* Executing the shell failed. */
1472                         perror(shell);
1473                         exit(1);
1474
1475                 } else {
1476                         /* Launch login(1). */
1477
1478                         execl(LOGIN_PROGRAM, "login", "-h", hostname,
1479 #ifdef LOGIN_NEEDS_TERM
1480                              s->term? s->term : "unknown",
1481 #endif
1482                              "-p", "-f", "--", pw->pw_name, (char *)NULL);
1483
1484                         /* Login couldn't be executed, die. */
1485
1486                         perror("login");
1487                         exit(1);
1488                 }
1489         }
1490         /*
1491          * Execute the command using the user's shell.  This uses the -c
1492          * option to execute the command.
1493          */
1494         argv[0] = (char *) cp;
1495         argv[1] = "-c";
1496         argv[2] = (char *) command;
1497         argv[3] = NULL;
1498         execve(shell, argv, env);
1499         perror(shell);
1500         exit(1);
1501 }
1502
1503 Session *
1504 session_new(void)
1505 {
1506         int i;
1507         static int did_init = 0;
1508         if (!did_init) {
1509                 debug("session_new: init");
1510                 for(i = 0; i < MAX_SESSIONS; i++) {
1511                         sessions[i].used = 0;
1512                 }
1513                 did_init = 1;
1514         }
1515         for(i = 0; i < MAX_SESSIONS; i++) {
1516                 Session *s = &sessions[i];
1517                 if (! s->used) {
1518                         memset(s, 0, sizeof(*s));
1519                         s->chanid = -1;
1520                         s->ptyfd = -1;
1521                         s->ttyfd = -1;
1522                         s->used = 1;
1523                         s->self = i;
1524                         debug("session_new: session %d", i);
1525                         return s;
1526                 }
1527         }
1528         return NULL;
1529 }
1530
1531 static void
1532 session_dump(void)
1533 {
1534         int i;
1535         for(i = 0; i < MAX_SESSIONS; i++) {
1536                 Session *s = &sessions[i];
1537                 debug("dump: used %d session %d %p channel %d pid %d",
1538                     s->used,
1539                     s->self,
1540                     s,
1541                     s->chanid,
1542                     s->pid);
1543         }
1544 }
1545
1546 int
1547 session_open(Authctxt *authctxt, int chanid)
1548 {
1549         Session *s = session_new();
1550         debug("session_open: channel %d", chanid);
1551         if (s == NULL) {
1552                 error("no more sessions");
1553                 return 0;
1554         }
1555         s->authctxt = authctxt;
1556         s->pw = authctxt->pw;
1557         if (s->pw == NULL)
1558                 fatal("no user for session %d", s->self);
1559         debug("session_open: session %d: link with channel %d", s->self, chanid);
1560         s->chanid = chanid;
1561         return 1;
1562 }
1563
1564 static Session *
1565 session_by_channel(int id)
1566 {
1567         int i;
1568         for(i = 0; i < MAX_SESSIONS; i++) {
1569                 Session *s = &sessions[i];
1570                 if (s->used && s->chanid == id) {
1571                         debug("session_by_channel: session %d channel %d", i, id);
1572                         return s;
1573                 }
1574         }
1575         debug("session_by_channel: unknown channel %d", id);
1576         session_dump();
1577         return NULL;
1578 }
1579
1580 static Session *
1581 session_by_pid(pid_t pid)
1582 {
1583         int i;
1584         debug("session_by_pid: pid %d", pid);
1585         for(i = 0; i < MAX_SESSIONS; i++) {
1586                 Session *s = &sessions[i];
1587                 if (s->used && s->pid == pid)
1588                         return s;
1589         }
1590         error("session_by_pid: unknown pid %d", pid);
1591         session_dump();
1592         return NULL;
1593 }
1594
1595 static int
1596 session_window_change_req(Session *s)
1597 {
1598         s->col = packet_get_int();
1599         s->row = packet_get_int();
1600         s->xpixel = packet_get_int();
1601         s->ypixel = packet_get_int();
1602         packet_done();
1603         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1604         return 1;
1605 }
1606
1607 static int
1608 session_pty_req(Session *s)
1609 {
1610         u_int len;
1611         int n_bytes;
1612
1613         if (no_pty_flag) {
1614                 debug("Allocating a pty not permitted for this authentication.");
1615                 return 0;
1616         }
1617         if (s->ttyfd != -1) {
1618                 packet_disconnect("Protocol error: you already have a pty.");
1619                 return 0;
1620         }
1621
1622         s->term = packet_get_string(&len);
1623
1624         if (compat20) {
1625                 s->col = packet_get_int();
1626                 s->row = packet_get_int();
1627         } else {
1628                 s->row = packet_get_int();
1629                 s->col = packet_get_int();
1630         }
1631         s->xpixel = packet_get_int();
1632         s->ypixel = packet_get_int();
1633
1634         if (strcmp(s->term, "") == 0) {
1635                 xfree(s->term);
1636                 s->term = NULL;
1637         }
1638
1639         /* Allocate a pty and open it. */
1640         debug("Allocating pty.");
1641         if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1642                 if (s->term)
1643                         xfree(s->term);
1644                 s->term = NULL;
1645                 s->ptyfd = -1;
1646                 s->ttyfd = -1;
1647                 error("session_pty_req: session %d alloc failed", s->self);
1648                 return 0;
1649         }
1650         debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1651
1652         /* for SSH1 the tty modes length is not given */
1653         if (!compat20)
1654                 n_bytes = packet_remaining();
1655         tty_parse_modes(s->ttyfd, &n_bytes);
1656
1657         /*
1658          * Add a cleanup function to clear the utmp entry and record logout
1659          * time in case we call fatal() (e.g., the connection gets closed).
1660          */
1661         fatal_add_cleanup(session_pty_cleanup, (void *)s);
1662         pty_setowner(s->pw, s->tty);
1663
1664         /* Set window size from the packet. */
1665         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1666
1667         packet_done();
1668         session_proctitle(s);
1669         return 1;
1670 }
1671
1672 static int
1673 session_subsystem_req(Session *s)
1674 {
1675         struct stat st;
1676         u_int len;
1677         int success = 0;
1678         char *cmd, *subsys = packet_get_string(&len);
1679         int i;
1680
1681         packet_done();
1682         log("subsystem request for %s", subsys);
1683
1684         for (i = 0; i < options.num_subsystems; i++) {
1685                 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1686                         cmd = options.subsystem_command[i];
1687                         if (stat(cmd, &st) < 0) {
1688                                 error("subsystem: cannot stat %s: %s", cmd,
1689                                     strerror(errno));
1690                                 break;
1691                         }
1692                         debug("subsystem: exec() %s", cmd);
1693                         s->is_subsystem = 1;
1694                         do_exec(s, cmd);
1695                         success = 1;
1696                 }
1697         }
1698
1699         if (!success)
1700                 log("subsystem request for %s failed, subsystem not found",
1701                     subsys);
1702
1703         xfree(subsys);
1704         return success;
1705 }
1706
1707 static int
1708 session_x11_req(Session *s)
1709 {
1710         int success;
1711
1712         s->single_connection = packet_get_char();
1713         s->auth_proto = packet_get_string(NULL);
1714         s->auth_data = packet_get_string(NULL);
1715         s->screen = packet_get_int();
1716         packet_done();
1717
1718         success = session_setup_x11fwd(s);
1719         if (!success) {
1720                 xfree(s->auth_proto);
1721                 xfree(s->auth_data);
1722                 s->auth_proto = NULL;
1723                 s->auth_data = NULL;
1724         }
1725         return success;
1726 }
1727
1728 static int
1729 session_shell_req(Session *s)
1730 {
1731         packet_done();
1732         do_exec(s, NULL);
1733         return 1;
1734 }
1735
1736 static int
1737 session_exec_req(Session *s)
1738 {
1739         u_int len;
1740         char *command = packet_get_string(&len);
1741         packet_done();
1742         do_exec(s, command);
1743         xfree(command);
1744         return 1;
1745 }
1746
1747 static int
1748 session_auth_agent_req(Session *s)
1749 {
1750         static int called = 0;
1751         packet_done();
1752         if (no_agent_forwarding_flag) {
1753                 debug("session_auth_agent_req: no_agent_forwarding_flag");
1754                 return 0;
1755         }
1756         if (called) {
1757                 return 0;
1758         } else {
1759                 called = 1;
1760                 return auth_input_request_forwarding(s->pw);
1761         }
1762 }
1763
1764 void
1765 session_input_channel_req(int id, void *arg)
1766 {
1767         u_int len;
1768         int reply;
1769         int success = 0;
1770         char *rtype;
1771         Session *s;
1772         Channel *c;
1773
1774         rtype = packet_get_string(&len);
1775         reply = packet_get_char();
1776
1777         s = session_by_channel(id);
1778         if (s == NULL)
1779                 fatal("session_input_channel_req: channel %d: no session", id);
1780         c = channel_lookup(id);
1781         if (c == NULL)
1782                 fatal("session_input_channel_req: channel %d: bad channel", id);
1783
1784         debug("session_input_channel_req: session %d channel %d request %s reply %d",
1785             s->self, id, rtype, reply);
1786
1787         /*
1788          * a session is in LARVAL state until a shell, a command
1789          * or a subsystem is executed
1790          */
1791         if (c->type == SSH_CHANNEL_LARVAL) {
1792                 if (strcmp(rtype, "shell") == 0) {
1793                         success = session_shell_req(s);
1794                 } else if (strcmp(rtype, "exec") == 0) {
1795                         success = session_exec_req(s);
1796                 } else if (strcmp(rtype, "pty-req") == 0) {
1797                         success =  session_pty_req(s);
1798                 } else if (strcmp(rtype, "x11-req") == 0) {
1799                         success = session_x11_req(s);
1800                 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1801                         success = session_auth_agent_req(s);
1802                 } else if (strcmp(rtype, "subsystem") == 0) {
1803                         success = session_subsystem_req(s);
1804                 }
1805         }
1806         if (strcmp(rtype, "window-change") == 0) {
1807                 success = session_window_change_req(s);
1808         }
1809
1810         if (reply) {
1811                 packet_start(success ?
1812                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1813                 packet_put_int(c->remote_id);
1814                 packet_send();
1815         }
1816         xfree(rtype);
1817 }
1818
1819 void
1820 session_set_fds(Session *s, int fdin, int fdout, int fderr)
1821 {
1822         if (!compat20)
1823                 fatal("session_set_fds: called for proto != 2.0");
1824         /*
1825          * now that have a child and a pipe to the child,
1826          * we can activate our channel and register the fd's
1827          */
1828         if (s->chanid == -1)
1829                 fatal("no channel for session %d", s->self);
1830         channel_set_fds(s->chanid,
1831             fdout, fdin, fderr,
1832             fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1833             1);
1834 }
1835
1836 /*
1837  * Function to perform pty cleanup. Also called if we get aborted abnormally
1838  * (e.g., due to a dropped connection).
1839  */
1840 static void
1841 session_pty_cleanup(void *session)
1842 {
1843         Session *s = session;
1844
1845         if (s == NULL) {
1846                 error("session_pty_cleanup: no session");
1847                 return;
1848         }
1849         if (s->ttyfd == -1)
1850                 return;
1851
1852         debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1853
1854         /* Record that the user has logged out. */
1855         if (s->pid != 0)
1856                 record_logout(s->pid, s->tty);
1857
1858         /* Release the pseudo-tty. */
1859         pty_release(s->tty);
1860
1861         /*
1862          * Close the server side of the socket pairs.  We must do this after
1863          * the pty cleanup, so that another process doesn't get this pty
1864          * while we're still cleaning up.
1865          */
1866         if (close(s->ptymaster) < 0)
1867                 error("close(s->ptymaster): %s", strerror(errno));
1868 }
1869
1870 static void
1871 session_exit_message(Session *s, int status)
1872 {
1873         Channel *c;
1874         if (s == NULL)
1875                 fatal("session_close: no session");
1876         c = channel_lookup(s->chanid);
1877         if (c == NULL)
1878                 fatal("session_exit_message: session %d: no channel %d",
1879                     s->self, s->chanid);
1880         debug("session_exit_message: session %d channel %d pid %d",
1881             s->self, s->chanid, s->pid);
1882
1883         if (WIFEXITED(status)) {
1884                 channel_request_start(s->chanid,
1885                     "exit-status", 0);
1886                 packet_put_int(WEXITSTATUS(status));
1887                 packet_send();
1888         } else if (WIFSIGNALED(status)) {
1889                 channel_request_start(s->chanid,
1890                     "exit-signal", 0);
1891                 packet_put_int(WTERMSIG(status));
1892 #ifdef WCOREDUMP
1893                 packet_put_char(WCOREDUMP(status));
1894 #else /* WCOREDUMP */
1895                 packet_put_char(0);
1896 #endif /* WCOREDUMP */
1897                 packet_put_cstring("");
1898                 packet_put_cstring("");
1899                 packet_send();
1900         } else {
1901                 /* Some weird exit cause.  Just exit. */
1902                 packet_disconnect("wait returned status %04x.", status);
1903         }
1904
1905         /* disconnect channel */
1906         debug("session_exit_message: release channel %d", s->chanid);
1907         channel_cancel_cleanup(s->chanid);
1908         /*
1909          * emulate a write failure with 'chan_write_failed', nobody will be
1910          * interested in data we write.
1911          * Note that we must not call 'chan_read_failed', since there could
1912          * be some more data waiting in the pipe.
1913          */
1914         if (c->ostate != CHAN_OUTPUT_CLOSED)
1915                 chan_write_failed(c);
1916         s->chanid = -1;
1917 }
1918
1919 static void
1920 session_close(Session *s)
1921 {
1922         debug("session_close: session %d pid %d", s->self, s->pid);
1923         if (s->ttyfd != -1) {
1924                 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1925                 session_pty_cleanup(s);
1926         }
1927         if (s->term)
1928                 xfree(s->term);
1929         if (s->display)
1930                 xfree(s->display);
1931         if (s->auth_data)
1932                 xfree(s->auth_data);
1933         if (s->auth_proto)
1934                 xfree(s->auth_proto);
1935         s->used = 0;
1936         session_proctitle(s);
1937 }
1938
1939 void
1940 session_close_by_pid(pid_t pid, int status)
1941 {
1942         Session *s = session_by_pid(pid);
1943         if (s == NULL) {
1944                 debug("session_close_by_pid: no session for pid %d", pid);
1945                 return;
1946         }
1947         if (s->chanid != -1)
1948                 session_exit_message(s, status);
1949         session_close(s);
1950 }
1951
1952 /*
1953  * this is called when a channel dies before
1954  * the session 'child' itself dies
1955  */
1956 void
1957 session_close_by_channel(int id, void *arg)
1958 {
1959         Session *s = session_by_channel(id);
1960         if (s == NULL) {
1961                 debug("session_close_by_channel: no session for id %d", id);
1962                 return;
1963         }
1964         debug("session_close_by_channel: channel %d child %d", id, s->pid);
1965         if (s->pid != 0) {
1966                 /* delay detach */
1967                 debug("session_close_by_channel: channel %d: has child", id);
1968                 return;
1969         }
1970         /* detach by removing callback */
1971         channel_cancel_cleanup(s->chanid);
1972         s->chanid = -1;
1973         session_close(s);
1974 }
1975
1976 void
1977 session_destroy_all(void)
1978 {
1979         int i;
1980         for(i = 0; i < MAX_SESSIONS; i++) {
1981                 Session *s = &sessions[i];
1982                 if (s->used)
1983                         session_close(s);
1984         }
1985 }
1986
1987 static char *
1988 session_tty_list(void)
1989 {
1990         static char buf[1024];
1991         int i;
1992         buf[0] = '\0';
1993         for(i = 0; i < MAX_SESSIONS; i++) {
1994                 Session *s = &sessions[i];
1995                 if (s->used && s->ttyfd != -1) {
1996                         if (buf[0] != '\0')
1997                                 strlcat(buf, ",", sizeof buf);
1998                         strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1999                 }
2000         }
2001         if (buf[0] == '\0')
2002                 strlcpy(buf, "notty", sizeof buf);
2003         return buf;
2004 }
2005
2006 void
2007 session_proctitle(Session *s)
2008 {
2009         if (s->pw == NULL)
2010                 error("no user for session %d", s->self);
2011         else
2012                 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2013 }
2014
2015 int
2016 session_setup_x11fwd(Session *s)
2017 {
2018         struct stat st;
2019
2020         if (no_x11_forwarding_flag) {
2021                 packet_send_debug("X11 forwarding disabled in user configuration file.");
2022                 return 0;
2023         }
2024         if (!options.x11_forwarding) {
2025                 debug("X11 forwarding disabled in server configuration file.");
2026                 return 0;
2027         }
2028         if (!options.xauth_location ||
2029             (stat(options.xauth_location, &st) == -1)) {
2030                 packet_send_debug("No xauth program; cannot forward with spoofing.");
2031                 return 0;
2032         }
2033         if (options.use_login) {
2034                 packet_send_debug("X11 forwarding disabled; "
2035                     "not compatible with UseLogin=yes.");
2036                 return 0;
2037         }
2038         if (s->display != NULL) {
2039                 debug("X11 display already set.");
2040                 return 0;
2041         }
2042         s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
2043         if (s->display == NULL) {
2044                 debug("x11_create_display_inet failed.");
2045                 return 0;
2046         }
2047         return 1;
2048 }
2049
2050 static void
2051 do_authenticated2(Authctxt *authctxt)
2052 {
2053         server_loop2(authctxt);
2054 }