openssh/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 char *aixloginmsg;
 163 #endif /* WITH_AIXAUTHENTICATE */
 164
 165 #ifdef HAVE_LOGIN_CAP
 166 static login_cap_t *lc;
 167 #endif
 168
 169 void
 170 do_authenticated(Authctxt *authctxt)
 171 {
 172         /*
 173          * Cancel the alarm we set to limit the time taken for
 174          * authentication.
 175          */
 176         alarm(0);
 177         if (startup_pipe != -1) {
 178                 close(startup_pipe);
 179                 startup_pipe = -1;
 180         }
 181 #if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
 182         if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
 183                 error("unable to get login class");
 184                 return;
 185         }
 186 #ifdef BSD_AUTH
 187         if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
 188                 packet_disconnect("Approval failure for %s",
 189                     authctxt->pw->pw_name);
 190         }
 191 #endif
 192 #endif
 193 #ifdef WITH_AIXAUTHENTICATE
 194         /* We don't have a pty yet, so just label the line as "ssh" */
 195         if (loginsuccess(authctxt->user,
 196             get_canonical_hostname(options.reverse_mapping_check),
 197             "ssh", &aixloginmsg) < 0)
 198                 aixloginmsg = NULL;
 199 #endif /* WITH_AIXAUTHENTICATE */
 200
 201         /* setup the channel layer */
 202         if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
 203                 channel_permit_all_opens();
 204
 205         if (compat20)
 206                 do_authenticated2(authctxt);
 207         else
 208                 do_authenticated1(authctxt);
 209
 210         /* remove agent socket */
 211         if (auth_get_socket_name())
 212                 auth_sock_cleanup_proc(authctxt->pw);
 213 #ifdef KRB4
 214         if (options.kerberos_ticket_cleanup)
 215                 krb4_cleanup_proc(authctxt);
 216 #endif
 217 #ifdef KRB5
 218         if (options.kerberos_ticket_cleanup)
 219                 krb5_cleanup_proc(authctxt);
 220 #endif
 221 }
 222
 223 /*
 224  * Prepares for an interactive session.  This is called after the user has
 225  * been successfully authenticated.  During this message exchange, pseudo
 226  * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
 227  * are requested, etc.
 228  */
 229 static void
 230 do_authenticated1(Authctxt *authctxt)
 231 {
 232         Session *s;
 233         char *command;
 234         int success, type, plen, screen_flag;
 235         int compression_level = 0, enable_compression_after_reply = 0;
 236         u_int proto_len, data_len, dlen;
 237
 238         s = session_new();
 239         s->authctxt = authctxt;
 240         s->pw = authctxt->pw;
 241
 242         /*
 243          * We stay in this loop until the client requests to execute a shell
 244          * or a command.
 245          */
 246         for (;;) {
 247                 success = 0;
 248
 249                 /* Get a packet from the client. */
 250                 type = packet_read(&plen);
 251
 252                 /* Process the packet. */
 253                 switch (type) {
 254                 case SSH_CMSG_REQUEST_COMPRESSION:
 255                         packet_integrity_check(plen, 4, type);
 256                         compression_level = packet_get_int();
 257                         if (compression_level < 1 || compression_level > 9) {
 258                                 packet_send_debug("Received illegal compression level %d.",
 259                                      compression_level);
 260                                 break;
 261                         }
 262                         /* Enable compression after we have responded with SUCCESS. */
 263                         enable_compression_after_reply = 1;
 264                         success = 1;
 265                         break;
 266
 267                 case SSH_CMSG_REQUEST_PTY:
 268                         success = session_pty_req(s);
 269                         break;
 270
 271                 case SSH_CMSG_X11_REQUEST_FORWARDING:
 272                         s->auth_proto = packet_get_string(&proto_len);
 273                         s->auth_data = packet_get_string(&data_len);
 274
 275                         screen_flag = packet_get_protocol_flags() &
 276                             SSH_PROTOFLAG_SCREEN_NUMBER;
 277                         debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
 278
 279                         if (packet_remaining() == 4) {
 280                                 if (!screen_flag)
 281                                         debug2("Buggy client: "
 282                                             "X11 screen flag missing");
 283                                 s->screen = packet_get_int();
 284                         } else {
 285                                 s->screen = 0;
 286                         }
 287                         packet_done();
 288                         success = session_setup_x11fwd(s);
 289                         if (!success) {
 290                                 xfree(s->auth_proto);
 291                                 xfree(s->auth_data);
 292                                 s->auth_proto = NULL;
 293                                 s->auth_data = NULL;
 294                         }
 295                         break;
 296
 297                 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
 298                         if (no_agent_forwarding_flag || compat13) {
 299                                 debug("Authentication agent forwarding not permitted for this authentication.");
 300                                 break;
 301                         }
 302                         debug("Received authentication agent forwarding request.");
 303                         success = auth_input_request_forwarding(s->pw);
 304                         break;
 305
 306                 case SSH_CMSG_PORT_FORWARD_REQUEST:
 307                         if (no_port_forwarding_flag) {
 308                                 debug("Port forwarding not permitted for this authentication.");
 309                                 break;
 310                         }
 311                         if (!options.allow_tcp_forwarding) {
 312                                 debug("Port forwarding not permitted.");
 313                                 break;
 314                         }
 315                         debug("Received TCP/IP port forwarding request.");
 316                         channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
 317                         success = 1;
 318                         break;
 319
 320                 case SSH_CMSG_MAX_PACKET_SIZE:
 321                         if (packet_set_maxsize(packet_get_int()) > 0)
 322                                 success = 1;
 323                         break;
 324
 325 #if defined(AFS) || defined(KRB5)
 326                 case SSH_CMSG_HAVE_KERBEROS_TGT:
 327                         if (!options.kerberos_tgt_passing) {
 328                                 verbose("Kerberos TGT passing disabled.");
 329                         } else {
 330                                 char *kdata = packet_get_string(&dlen);
 331                                 packet_integrity_check(plen, 4 + dlen, type);
 332
 333                                 /* XXX - 0x41, see creds_to_radix version */
 334                                 if (kdata[0] != 0x41) {
 335 #ifdef KRB5
 336                                         krb5_data tgt;
 337                                         tgt.data = kdata;
 338                                         tgt.length = dlen;
 339
 340                                         if (auth_krb5_tgt(s->authctxt, &tgt))
 341                                                 success = 1;
 342                                         else
 343                                                 verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
 344 #endif /* KRB5 */
 345                                 } else {
 346 #ifdef AFS
 347                                         if (auth_krb4_tgt(s->authctxt, kdata))
 348                                                 success = 1;
 349                                         else
 350                                                 verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
 351 #endif /* AFS */
 352                                 }
 353                                 xfree(kdata);
 354                         }
 355                         break;
 356 #endif /* AFS || KRB5 */
 357
 358 #ifdef AFS
 359                 case SSH_CMSG_HAVE_AFS_TOKEN:
 360                         if (!options.afs_token_passing || !k_hasafs()) {
 361                                 verbose("AFS token passing disabled.");
 362                         } else {
 363                                 /* Accept AFS token. */
 364                                 char *token = packet_get_string(&dlen);
 365                                 packet_integrity_check(plen, 4 + dlen, type);
 366
 367                                 if (auth_afs_token(s->authctxt, token))
 368                                         success = 1;
 369                                 else
 370                                         verbose("AFS token refused for %.100s",
 371                                             s->authctxt->user);
 372                                 xfree(token);
 373                         }
 374                         break;
 375 #endif /* AFS */
 376
 377                 case SSH_CMSG_EXEC_SHELL:
 378                 case SSH_CMSG_EXEC_CMD:
 379                         if (type == SSH_CMSG_EXEC_CMD) {
 380                                 command = packet_get_string(&dlen);
 381                                 debug("Exec command '%.500s'", command);
 382                                 do_exec(s, command);
 383                                 xfree(command);
 384                         } else {
 385                                 do_exec(s, NULL);
 386                         }
 387                         packet_done();
 388                         session_close(s);
 389                         return;
 390
 391                 default:
 392                         /*
 393                          * Any unknown messages in this phase are ignored,
 394                          * and a failure message is returned.
 395                          */
 396                         log("Unknown packet type received after authentication: %d", type);
 397                 }
 398                 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
 399                 packet_send();
 400                 packet_write_wait();
 401
 402                 /* Enable compression now that we have replied if appropriate. */
 403                 if (enable_compression_after_reply) {
 404                         enable_compression_after_reply = 0;
 405                         packet_start_compression(compression_level);
 406                 }
 407         }
 408 }
 409
 410 /*
 411  * This is called to fork and execute a command when we have no tty.  This
 412  * will call do_child from the child, and server_loop from the parent after
 413  * setting up file descriptors and such.
 414  */
 415 void
 416 do_exec_no_pty(Session *s, const char *command)
 417 {
 418         int pid;
 419
 420 #ifdef USE_PIPES
 421         int pin[2], pout[2], perr[2];
 422         /* Allocate pipes for communicating with the program. */
 423         if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
 424                 packet_disconnect("Could not create pipes: %.100s",
 425                                   strerror(errno));
 426 #else /* USE_PIPES */
 427         int inout[2], err[2];
 428         /* Uses socket pairs to communicate with the program. */
 429         if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
 430             socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
 431                 packet_disconnect("Could not create socket pairs: %.100s",
 432                                   strerror(errno));
 433 #endif /* USE_PIPES */
 434         if (s == NULL)
 435                 fatal("do_exec_no_pty: no session");
 436
 437         session_proctitle(s);
 438
 439 #if defined(USE_PAM)
 440         do_pam_session(s->pw->pw_name, NULL);
 441         do_pam_setcred(1);
 442         if (is_pam_password_change_required())
 443                 packet_disconnect("Password change required but no "
 444                     "TTY available");
 445 #endif /* USE_PAM */
 446
 447         /* Fork the child. */
 448         if ((pid = fork()) == 0) {
 449                 /* Child.  Reinitialize the log since the pid has changed. */
 450                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 451
 452                 /*
 453                  * Create a new session and process group since the 4.4BSD
 454                  * setlogin() affects the entire process group.
 455                  */
 456                 if (setsid() < 0)
 457                         error("setsid failed: %.100s", strerror(errno));
 458
 459 #ifdef USE_PIPES
 460                 /*
 461                  * Redirect stdin.  We close the parent side of the socket
 462                  * pair, and make the child side the standard input.
 463                  */
 464                 close(pin[1]);
 465                 if (dup2(pin[0], 0) < 0)
 466                         perror("dup2 stdin");
 467                 close(pin[0]);
 468
 469                 /* Redirect stdout. */
 470                 close(pout[0]);
 471                 if (dup2(pout[1], 1) < 0)
 472                         perror("dup2 stdout");
 473                 close(pout[1]);
 474
 475                 /* Redirect stderr. */
 476                 close(perr[0]);
 477                 if (dup2(perr[1], 2) < 0)
 478                         perror("dup2 stderr");
 479                 close(perr[1]);
 480 #else /* USE_PIPES */
 481                 /*
 482                  * Redirect stdin, stdout, and stderr.  Stdin and stdout will
 483                  * use the same socket, as some programs (particularly rdist)
 484                  * seem to depend on it.
 485                  */
 486                 close(inout[1]);
 487                 close(err[1]);
 488                 if (dup2(inout[0], 0) < 0)      /* stdin */
 489                         perror("dup2 stdin");
 490                 if (dup2(inout[0], 1) < 0)      /* stdout.  Note: same socket as stdin. */
 491                         perror("dup2 stdout");
 492                 if (dup2(err[0], 2) < 0)        /* stderr */
 493                         perror("dup2 stderr");
 494 #endif /* USE_PIPES */
 495
 496                 /* Do processing for the child (exec command etc). */
 497                 do_child(s, command);
 498                 /* NOTREACHED */
 499         }
 500 #ifdef HAVE_CYGWIN
 501         if (is_winnt)
 502                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 503 #endif
 504         if (pid < 0)
 505                 packet_disconnect("fork failed: %.100s", strerror(errno));
 506         s->pid = pid;
 507         /* Set interactive/non-interactive mode. */
 508         packet_set_interactive(s->display != NULL);
 509 #ifdef USE_PIPES
 510         /* We are the parent.  Close the child sides of the pipes. */
 511         close(pin[0]);
 512         close(pout[1]);
 513         close(perr[1]);
 514
 515         if (compat20) {
 516                 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
 517         } else {
 518                 /* Enter the interactive session. */
 519                 server_loop(pid, pin[1], pout[0], perr[0]);
 520                 /* server_loop has closed pin[1], pout[0], and perr[0]. */
 521         }
 522 #else /* USE_PIPES */
 523         /* We are the parent.  Close the child sides of the socket pairs. */
 524         close(inout[0]);
 525         close(err[0]);
 526
 527         /*
 528          * Enter the interactive session.  Note: server_loop must be able to
 529          * handle the case that fdin and fdout are the same.
 530          */
 531         if (compat20) {
 532                 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
 533         } else {
 534                 server_loop(pid, inout[1], inout[1], err[1]);
 535                 /* server_loop has closed inout[1] and err[1]. */
 536         }
 537 #endif /* USE_PIPES */
 538 }
 539
 540 /*
 541  * This is called to fork and execute a command when we have a tty.  This
 542  * will call do_child from the child, and server_loop from the parent after
 543  * setting up file descriptors, controlling tty, updating wtmp, utmp,
 544  * lastlog, and other such operations.
 545  */
 546 void
 547 do_exec_pty(Session *s, const char *command)
 548 {
 549         int fdout, ptyfd, ttyfd, ptymaster;
 550         pid_t pid;
 551
 552         if (s == NULL)
 553                 fatal("do_exec_pty: no session");
 554         ptyfd = s->ptyfd;
 555         ttyfd = s->ttyfd;
 556
 557 #if defined(USE_PAM)
 558         do_pam_session(s->pw->pw_name, s->tty);
 559         do_pam_setcred(1);
 560 #endif
 561
 562         /* Fork the child. */
 563         if ((pid = fork()) == 0) {
 564
 565                 /* Child.  Reinitialize the log because the pid has changed. */
 566                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 567                 /* Close the master side of the pseudo tty. */
 568                 close(ptyfd);
 569
 570                 /* Make the pseudo tty our controlling tty. */
 571                 pty_make_controlling_tty(&ttyfd, s->tty);
 572
 573                 /* Redirect stdin/stdout/stderr from the pseudo tty. */
 574                 if (dup2(ttyfd, 0) < 0)
 575                         error("dup2 stdin: %s", strerror(errno));
 576                 if (dup2(ttyfd, 1) < 0)
 577                         error("dup2 stdout: %s", strerror(errno));
 578                 if (dup2(ttyfd, 2) < 0)
 579                         error("dup2 stderr: %s", strerror(errno));
 580
 581                 /* Close the extra descriptor for the pseudo tty. */
 582                 close(ttyfd);
 583
 584                 /* record login, etc. similar to login(1) */
 585 #ifndef HAVE_OSF_SIA
 586                 if (!(options.use_login && command == NULL))
 587                         do_login(s, command);
 588 # ifdef LOGIN_NEEDS_UTMPX
 589                 else
 590                         do_pre_login(s);
 591 # endif
 592 #endif
 593
 594                 /* Do common processing for the child, such as execing the command. */
 595                 do_child(s, command);
 596                 /* NOTREACHED */
 597         }
 598 #ifdef HAVE_CYGWIN
 599         if (is_winnt)
 600                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 601 #endif
 602         if (pid < 0)
 603                 packet_disconnect("fork failed: %.100s", strerror(errno));
 604         s->pid = pid;
 605
 606         /* Parent.  Close the slave side of the pseudo tty. */
 607         close(ttyfd);
 608
 609         /*
 610          * Create another descriptor of the pty master side for use as the
 611          * standard input.  We could use the original descriptor, but this
 612          * simplifies code in server_loop.  The descriptor is bidirectional.
 613          */
 614         fdout = dup(ptyfd);
 615         if (fdout < 0)
 616                 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
 617
 618         /* we keep a reference to the pty master */
 619         ptymaster = dup(ptyfd);
 620         if (ptymaster < 0)
 621                 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
 622         s->ptymaster = ptymaster;
 623
 624         /* Enter interactive session. */
 625         packet_set_interactive(1);
 626         if (compat20) {
 627                 session_set_fds(s, ptyfd, fdout, -1);
 628         } else {
 629                 server_loop(pid, ptyfd, fdout, -1);
 630                 /* server_loop _has_ closed ptyfd and fdout. */
 631         }
 632 }
 633
 634 #ifdef LOGIN_NEEDS_UTMPX
 635 static void
 636 do_pre_login(Session *s)
 637 {
 638         socklen_t fromlen;
 639         struct sockaddr_storage from;
 640         pid_t pid = getpid();
 641
 642         /*
 643          * Get IP address of client. If the connection is not a socket, let
 644          * the address be 0.0.0.0.
 645          */
 646         memset(&from, 0, sizeof(from));
 647         if (packet_connection_is_on_socket()) {
 648                 fromlen = sizeof(from);
 649                 if (getpeername(packet_get_connection_in(),
 650                      (struct sockaddr *) & from, &fromlen) < 0) {
 651                         debug("getpeername: %.100s", strerror(errno));
 652                         fatal_cleanup();
 653                 }
 654         }
 655
 656         record_utmp_only(pid, s->tty, s->pw->pw_name,
 657             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 658             (struct sockaddr *)&from);
 659 }
 660 #endif
 661
 662 /*
 663  * This is called to fork and execute a command.  If another command is
 664  * to be forced, execute that instead.
 665  */
 666 void
 667 do_exec(Session *s, const char *command)
 668 {
 669         if (forced_command) {
 670                 original_command = command;
 671                 command = forced_command;
 672                 debug("Forced command '%.900s'", command);
 673         }
 674
 675         if (s->ttyfd != -1)
 676                 do_exec_pty(s, command);
 677         else
 678                 do_exec_no_pty(s, command);
 679
 680         original_command = NULL;
 681 }
 682
 683 /* administrative, login(1)-like work */
 684 void
 685 do_login(Session *s, const char *command)
 686 {
 687         char *time_string;
 688         char hostname[MAXHOSTNAMELEN];
 689         socklen_t fromlen;
 690         struct sockaddr_storage from;
 691         time_t last_login_time;
 692         struct passwd * pw = s->pw;
 693         pid_t pid = getpid();
 694
 695         /*
 696          * Get IP address of client. If the connection is not a socket, let
 697          * the address be 0.0.0.0.
 698          */
 699         memset(&from, 0, sizeof(from));
 700         if (packet_connection_is_on_socket()) {
 701                 fromlen = sizeof(from);
 702                 if (getpeername(packet_get_connection_in(),
 703                      (struct sockaddr *) & from, &fromlen) < 0) {
 704                         debug("getpeername: %.100s", strerror(errno));
 705                         fatal_cleanup();
 706                 }
 707         }
 708
 709         /* Get the time and hostname when the user last logged in. */
 710         if (options.print_lastlog) {
 711                 hostname[0] = '\0';
 712                 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
 713                     hostname, sizeof(hostname));
 714         }
 715
 716         /* Record that there was a login on that tty from the remote host. */
 717         record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
 718             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 719             (struct sockaddr *)&from);
 720
 721 #ifdef USE_PAM
 722         /*
 723          * If password change is needed, do it now.
 724          * This needs to occur before the ~/.hushlogin check.
 725          */
 726         if (is_pam_password_change_required()) {
 727                 print_pam_messages();
 728                 do_pam_chauthtok();
 729         }
 730 #endif
 731
 732         if (check_quietlogin(s, command))
 733                 return;
 734
 735 #ifdef USE_PAM
 736         if (!is_pam_password_change_required())
 737                 print_pam_messages();
 738 #endif /* USE_PAM */
 739 #ifdef WITH_AIXAUTHENTICATE
 740         if (aixloginmsg && *aixloginmsg)
 741                 printf("%s\n", aixloginmsg);
 742 #endif /* WITH_AIXAUTHENTICATE */
 743
 744         if (options.print_lastlog && last_login_time != 0) {
 745                 time_string = ctime(&last_login_time);
 746                 if (strchr(time_string, '\n'))
 747                         *strchr(time_string, '\n') = 0;
 748                 if (strcmp(hostname, "") == 0)
 749                         printf("Last login: %s\r\n", time_string);
 750                 else
 751                         printf("Last login: %s from %s\r\n", time_string, hostname);
 752         }
 753
 754         do_motd();
 755 }
 756
 757 /*
 758  * Display the message of the day.
 759  */
 760 void
 761 do_motd(void)
 762 {
 763         FILE *f;
 764         char buf[256];
 765
 766         if (options.print_motd) {
 767 #ifdef HAVE_LOGIN_CAP
 768                 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
 769                     "/etc/motd"), "r");
 770 #else
 771                 f = fopen("/etc/motd", "r");
 772 #endif
 773                 if (f) {
 774                         while (fgets(buf, sizeof(buf), f))
 775                                 fputs(buf, stdout);
 776                         fclose(f);
 777                 }
 778         }
 779 }
 780
 781
 782 /*
 783  * Check for quiet login, either .hushlogin or command given.
 784  */
 785 int
 786 check_quietlogin(Session *s, const char *command)
 787 {
 788         char buf[256];
 789         struct passwd *pw = s->pw;
 790         struct stat st;
 791
 792         /* Return 1 if .hushlogin exists or a command given. */
 793         if (command != NULL)
 794                 return 1;
 795         snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
 796 #ifdef HAVE_LOGIN_CAP
 797         if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
 798                 return 1;
 799 #else
 800         if (stat(buf, &st) >= 0)
 801                 return 1;
 802 #endif
 803         return 0;
 804 }
 805
 806 /*
 807  * Sets the value of the given variable in the environment.  If the variable
 808  * already exists, its value is overriden.
 809  */
 810 static void
 811 child_set_env(char ***envp, u_int *envsizep, const char *name,
 812               const char *value)
 813 {
 814         u_int i, namelen;
 815         char **env;
 816
 817         /*
 818          * Find the slot where the value should be stored.  If the variable
 819          * already exists, we reuse the slot; otherwise we append a new slot
 820          * at the end of the array, expanding if necessary.
 821          */
 822         env = *envp;
 823         namelen = strlen(name);
 824         for (i = 0; env[i]; i++)
 825                 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
 826                         break;
 827         if (env[i]) {
 828                 /* Reuse the slot. */
 829                 xfree(env[i]);
 830         } else {
 831                 /* New variable.  Expand if necessary. */
 832                 if (i >= (*envsizep) - 1) {
 833                         (*envsizep) += 50;
 834                         env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
 835                 }
 836                 /* Need to set the NULL pointer at end of array beyond the new slot. */
 837                 env[i + 1] = NULL;
 838         }
 839
 840         /* Allocate space and format the variable in the appropriate slot. */
 841         env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
 842         snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
 843 }
 844
 845 /*
 846  * Reads environment variables from the given file and adds/overrides them
 847  * into the environment.  If the file does not exist, this does nothing.
 848  * Otherwise, it must consist of empty lines, comments (line starts with '#')
 849  * and assignments of the form name=value.  No other forms are allowed.
 850  */
 851 static void
 852 read_environment_file(char ***env, u_int *envsize,
 853                       const char *filename)
 854 {
 855         FILE *f;
 856         char buf[4096];
 857         char *cp, *value;
 858
 859         f = fopen(filename, "r");
 860         if (!f)
 861                 return;
 862
 863         while (fgets(buf, sizeof(buf), f)) {
 864                 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
 865                         ;
 866                 if (!*cp || *cp == '#' || *cp == '\n')
 867                         continue;
 868                 if (strchr(cp, '\n'))
 869                         *strchr(cp, '\n') = '\0';
 870                 value = strchr(cp, '=');
 871                 if (value == NULL) {
 872                         fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
 873                         continue;
 874                 }
 875                 /*
 876                  * Replace the equals sign by nul, and advance value to
 877                  * the value string.
 878                  */
 879                 *value = '\0';
 880                 value++;
 881                 child_set_env(env, envsize, cp, value);
 882         }
 883         fclose(f);
 884 }
 885
 886 #ifdef USE_PAM
 887 /*
 888  * Sets any environment variables which have been specified by PAM
 889  */
 890 void do_pam_environment(char ***env, u_int *envsize)
 891 {
 892         char *equals, var_name[512], var_val[512];
 893         char **pam_env;
 894         int i;
 895
 896         if ((pam_env = fetch_pam_environment()) == NULL)
 897                 return;
 898
 899         for(i = 0; pam_env[i] != NULL; i++) {
 900                 if ((equals = strstr(pam_env[i], "=")) == NULL)
 901                         continue;
 902
 903                 if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) {
 904                         memset(var_name, '\0', sizeof(var_name));
 905                         memset(var_val, '\0', sizeof(var_val));
 906
 907                         strncpy(var_name, pam_env[i], equals - pam_env[i]);
 908                         strcpy(var_val, equals + 1);
 909
 910                         debug3("PAM environment: %s=%s", var_name, var_val);
 911
 912                         child_set_env(env, envsize, var_name, var_val);
 913                 }
 914         }
 915 }
 916 #endif /* USE_PAM */
 917
 918 #ifdef HAVE_CYGWIN
 919 void copy_environment(char ***env, u_int *envsize)
 920 {
 921         char *equals, var_name[512], var_val[512];
 922         int i;
 923
 924         for(i = 0; environ[i] != NULL; i++) {
 925                 if ((equals = strstr(environ[i], "=")) == NULL)
 926                         continue;
 927
 928                 if (strlen(environ[i]) < (sizeof(var_name) - 1)) {
 929                         memset(var_name, '\0', sizeof(var_name));
 930                         memset(var_val, '\0', sizeof(var_val));
 931
 932                         strncpy(var_name, environ[i], equals - environ[i]);
 933                         strcpy(var_val, equals + 1);
 934
 935                         debug3("Copy environment: %s=%s", var_name, var_val);
 936
 937                         child_set_env(env, envsize, var_name, var_val);
 938                 }
 939         }
 940 }
 941 #endif
 942
 943 #if defined(HAVE_GETUSERATTR)
 944 /*
 945  * AIX-specific login initialisation
 946  */
 947 void set_limit(char *user, char *soft, char *hard, int resource, int mult)
 948 {
 949         struct rlimit rlim;
 950         int slim, hlim;
 951
 952         getrlimit(resource, &rlim);
 953
 954         slim = 0;
 955         if (getuserattr(user, soft, &slim, SEC_INT) != -1) {
 956                 if (slim < 0) {
 957                         rlim.rlim_cur = RLIM_INFINITY;
 958                 } else if (slim != 0) {
 959                         /* See the wackiness below */
 960                         if (rlim.rlim_cur == slim * mult)
 961                                 slim = 0;
 962                         else
 963                                 rlim.rlim_cur = slim * mult;
 964                 }
 965         }
 966
 967         hlim = 0;
 968         if (getuserattr(user, hard, &hlim, SEC_INT) != -1) {
 969                 if (hlim < 0) {
 970                         rlim.rlim_max = RLIM_INFINITY;
 971                 } else if (hlim != 0) {
 972                         rlim.rlim_max = hlim * mult;
 973                 }
 974         }
 975
 976         /*
 977          * XXX For cpu and fsize the soft limit is set to the hard limit
 978          * if the hard limit is left at its default value and the soft limit
 979          * is changed from its default value, either by requesting it
 980          * (slim == 0) or by setting it to the current default.  At least
 981          * that's how rlogind does it.  If you're confused you're not alone.
 982          * Bug or feature? AIX 4.3.1.2
 983          */
 984         if ((!strcmp(soft, "fsize") || !strcmp(soft, "cpu"))
 985             && hlim == 0 && slim != 0)
 986                 rlim.rlim_max = rlim.rlim_cur;
 987         /* A specified hard limit limits the soft limit */
 988         else if (hlim > 0 && rlim.rlim_cur > rlim.rlim_max)
 989                 rlim.rlim_cur = rlim.rlim_max;
 990         /* A soft limit can increase a hard limit */
 991         else if (rlim.rlim_cur > rlim.rlim_max)
 992                 rlim.rlim_max = rlim.rlim_cur;
 993
 994         if (setrlimit(resource, &rlim) != 0)
 995                 error("setrlimit(%.10s) failed: %.100s", soft, strerror(errno));
 996 }
 997
 998 void set_limits_from_userattr(char *user)
 999 {
1000         int mask;
1001         char buf[16];
1002
1003         set_limit(user, S_UFSIZE, S_UFSIZE_HARD, RLIMIT_FSIZE, 512);
1004         set_limit(user, S_UCPU, S_UCPU_HARD, RLIMIT_CPU, 1);
1005         set_limit(user, S_UDATA, S_UDATA_HARD, RLIMIT_DATA, 512);
1006         set_limit(user, S_USTACK, S_USTACK_HARD, RLIMIT_STACK, 512);
1007         set_limit(user, S_URSS, S_URSS_HARD, RLIMIT_RSS, 512);
1008         set_limit(user, S_UCORE, S_UCORE_HARD, RLIMIT_CORE, 512);
1009 #if defined(S_UNOFILE)
1010         set_limit(user, S_UNOFILE, S_UNOFILE_HARD, RLIMIT_NOFILE, 1);
1011 #endif
1012
1013         if (getuserattr(user, S_UMASK, &mask, SEC_INT) != -1) {
1014                 /* Convert decimal to octal */
1015                 (void) snprintf(buf, sizeof(buf), "%d", mask);
1016                 if (sscanf(buf, "%o", &mask) == 1)
1017                         umask(mask);
1018         }
1019 }
1020 #endif /* defined(HAVE_GETUSERATTR) */
1021
1022 /*
1023  * Performs common processing for the child, such as setting up the
1024  * environment, closing extra file descriptors, setting the user and group
1025  * ids, and executing the command or shell.
1026  */
1027 void
1028 do_child(Session *s, const char *command)
1029 {
1030         const char *shell, *hostname = NULL, *cp = NULL;
1031         struct passwd *pw = s->pw;
1032         char buf[256];
1033         char cmd[1024];
1034         FILE *f = NULL;
1035         u_int envsize, i;
1036         char **env;
1037         extern char **environ;
1038         struct stat st;
1039         char *argv[10];
1040         int do_xauth;
1041 #ifdef WITH_IRIX_PROJECT
1042         prid_t projid;
1043 #endif /* WITH_IRIX_PROJECT */
1044 #ifdef WITH_IRIX_JOBS
1045         jid_t jid = 0;
1046 #else
1047 #ifdef WITH_IRIX_ARRAY
1048         int jid = 0;
1049 #endif /* WITH_IRIX_ARRAY */
1050 #endif /* WITH_IRIX_JOBS */
1051
1052         do_xauth =
1053             s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1054
1055         /* remove hostkey from the child's memory */
1056         destroy_sensitive_data();
1057
1058         /* login(1) is only called if we execute the login shell */
1059         if (options.use_login && command != NULL)
1060                 options.use_login = 0;
1061
1062 #if !defined(HAVE_OSF_SIA)
1063         if (!options.use_login) {
1064 # ifdef HAVE_LOGIN_CAP
1065                 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1066                         f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1067                             _PATH_NOLOGIN), "r");
1068 # else /* HAVE_LOGIN_CAP */
1069                 if (pw->pw_uid)
1070                         f = fopen(_PATH_NOLOGIN, "r");
1071 # endif /* HAVE_LOGIN_CAP */
1072                 if (f) {
1073                         /* /etc/nologin exists.  Print its contents and exit. */
1074                         while (fgets(buf, sizeof(buf), f))
1075                                 fputs(buf, stderr);
1076                         fclose(f);
1077                         exit(254);
1078                 }
1079         }
1080 #endif /* HAVE_OSF_SIA */
1081
1082         /* Set login name, uid, gid, and groups. */
1083         /* Login(1) does this as well, and it needs uid 0 for the "-h"
1084            switch, so we let login(1) to this for us. */
1085         if (!options.use_login) {
1086 #ifdef HAVE_OSF_SIA
1087                 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1088                 if (!check_quietlogin(s, command))
1089                         do_motd();
1090 #else /* HAVE_OSF_SIA */
1091 #ifdef HAVE_CYGWIN
1092                 if (is_winnt) {
1093 #else
1094                 if (getuid() == 0 || geteuid() == 0) {
1095 #endif
1096 # ifdef HAVE_GETUSERATTR
1097                         set_limits_from_userattr(pw->pw_name);
1098 # endif /* HAVE_GETUSERATTR */
1099 # ifdef HAVE_LOGIN_CAP
1100                         if (setusercontext(lc, pw, pw->pw_uid,
1101                             (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1102                                 perror("unable to set user context");
1103                                 exit(1);
1104                         }
1105 # else /* HAVE_LOGIN_CAP */
1106 #if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1107                         /* Sets login uid for accounting */
1108                         if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1109                                 error("setluid: %s", strerror(errno));
1110 #endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1111
1112                         if (setlogin(pw->pw_name) < 0)
1113                                 error("setlogin failed: %s", strerror(errno));
1114                         if (setgid(pw->pw_gid) < 0) {
1115                                 perror("setgid");
1116                                 exit(1);
1117                         }
1118                         /* Initialize the group list. */
1119                         if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1120                                 perror("initgroups");
1121                                 exit(1);
1122                         }
1123                         endgrent();
1124 #  ifdef USE_PAM
1125                         /*
1126                          * PAM credentials may take the form of
1127                          * supplementary groups. These will have been
1128                          * wiped by the above initgroups() call.
1129                          * Reestablish them here.
1130                          */
1131                         do_pam_setcred(0);
1132 #  endif /* USE_PAM */
1133 #  ifdef WITH_IRIX_JOBS
1134                         jid = jlimit_startjob(pw->pw_name, pw->pw_uid, "interactive");
1135                         if (jid == -1) {
1136                                 fatal("Failed to create job container: %.100s",
1137                                       strerror(errno));
1138                         }
1139 #  endif /* WITH_IRIX_JOBS */
1140 #  ifdef WITH_IRIX_ARRAY
1141                         /* initialize array session */
1142                         if (jid == 0) {
1143                                 if (newarraysess() != 0)
1144                                         fatal("Failed to set up new array session: %.100s",
1145                                               strerror(errno));
1146                         }
1147 #  endif /* WITH_IRIX_ARRAY */
1148 #  ifdef WITH_IRIX_PROJECT
1149                         /* initialize irix project info */
1150                         if ((projid = getdfltprojuser(pw->pw_name)) == -1) {
1151                           debug("Failed to get project id, using projid 0");
1152                           projid = 0;
1153                         }
1154                         if (setprid(projid))
1155                           fatal("Failed to initialize project %d for %s: %.100s",
1156                                 (int)projid, pw->pw_name, strerror(errno));
1157 #  endif /* WITH_IRIX_PROJECT */
1158 #ifdef WITH_IRIX_AUDIT
1159                         if (sysconf(_SC_AUDIT)) {
1160                                 debug("Setting sat id to %d", (int) pw->pw_uid);
1161                                 if (satsetid(pw->pw_uid))
1162                                         debug("error setting satid: %.100s", strerror(errno));
1163                         }
1164 #endif /* WITH_IRIX_AUDIT */
1165
1166 #ifdef _AIX
1167                         /*
1168                          * AIX has a "usrinfo" area where logname and
1169                          * other stuff is stored - a few applications
1170                          * actually use this and die if it's not set
1171                          */
1172                         if (s->ttyfd == -1)
1173                                 s->tty[0] = '\0';
1174                         cp = xmalloc(22 + strlen(s->tty) +
1175                             2 * strlen(pw->pw_name));
1176                         i = sprintf(cp, "LOGNAME=%s%cNAME=%s%cTTY=%s%c%c",
1177                             pw->pw_name, 0, pw->pw_name, 0, s->tty, 0, 0);
1178                         if (usrinfo(SETUINFO, cp, i) == -1)
1179                                 fatal("Couldn't set usrinfo: %s",
1180                                     strerror(errno));
1181                         debug3("AIX/UsrInfo: set len %d", i);
1182                         xfree(cp);
1183 #endif
1184
1185                         /* Permanently switch to the desired uid. */
1186                         permanently_set_uid(pw);
1187 # endif /* HAVE_LOGIN_CAP */
1188                 }
1189 #endif /* HAVE_OSF_SIA */
1190
1191 #ifdef HAVE_CYGWIN
1192                 if (is_winnt)
1193 #endif
1194                 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1195                         fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1196         }
1197         /*
1198          * Get the shell from the password data.  An empty shell field is
1199          * legal, and means /bin/sh.
1200          */
1201         shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1202 #ifdef HAVE_LOGIN_CAP
1203         shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1204 #endif
1205
1206         /* Initialize the environment. */
1207         envsize = 100;
1208         env = xmalloc(envsize * sizeof(char *));
1209         env[0] = NULL;
1210
1211 #ifdef HAVE_CYGWIN
1212         /*
1213          * The Windows environment contains some setting which are
1214          * important for a running system. They must not be dropped.
1215          */
1216         copy_environment(&env, &envsize);
1217 #endif
1218
1219         if (!options.use_login) {
1220                 /* Set basic environment. */
1221                 child_set_env(&env, &envsize, "USER", pw->pw_name);
1222                 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1223                 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1224 #ifdef HAVE_LOGIN_CAP
1225                 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
1226                 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1227 #else /* HAVE_LOGIN_CAP */
1228 # ifndef HAVE_CYGWIN
1229                 /*
1230                  * There's no standard path on Windows. The path contains
1231                  * important components pointing to the system directories,
1232                  * needed for loading shared libraries. So the path better
1233                  * remains intact here.
1234                  */
1235                 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1236 # endif /* HAVE_CYGWIN */
1237 #endif /* HAVE_LOGIN_CAP */
1238
1239                 snprintf(buf, sizeof buf, "%.200s/%.50s",
1240                          _PATH_MAILDIR, pw->pw_name);
1241                 child_set_env(&env, &envsize, "MAIL", buf);
1242
1243                 /* Normal systems set SHELL by default. */
1244                 child_set_env(&env, &envsize, "SHELL", shell);
1245         }
1246         if (getenv("TZ"))
1247                 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1248
1249         /* Set custom environment options from RSA authentication. */
1250         if (!options.use_login) {
1251                 while (custom_environment) {
1252                         struct envstring *ce = custom_environment;
1253                         char *s = ce->s;
1254                         int i;
1255                         for (i = 0; s[i] != '=' && s[i]; i++)
1256                                 ;
1257                         if (s[i] == '=') {
1258                                 s[i] = 0;
1259                                 child_set_env(&env, &envsize, s, s + i + 1);
1260                         }
1261                         custom_environment = ce->next;
1262                         xfree(ce->s);
1263                         xfree(ce);
1264                 }
1265         }
1266
1267         snprintf(buf, sizeof buf, "%.50s %d %d",
1268                  get_remote_ipaddr(), get_remote_port(), get_local_port());
1269         child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1270
1271         if (s->ttyfd != -1)
1272                 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1273         if (s->term)
1274                 child_set_env(&env, &envsize, "TERM", s->term);
1275         if (s->display)
1276                 child_set_env(&env, &envsize, "DISPLAY", s->display);
1277         if (original_command)
1278                 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1279                     original_command);
1280
1281 #ifdef _AIX
1282         if ((cp = getenv("AUTHSTATE")) != NULL)
1283                 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1284         if ((cp = getenv("KRB5CCNAME")) != NULL)
1285                 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1286         read_environment_file(&env, &envsize, "/etc/environment");
1287 #endif
1288 #ifdef KRB4
1289         if (s->authctxt->krb4_ticket_file)
1290                 child_set_env(&env, &envsize, "KRBTKFILE",
1291                     s->authctxt->krb4_ticket_file);
1292 #endif
1293 #ifdef KRB5
1294         if (s->authctxt->krb5_ticket_file)
1295                 child_set_env(&env, &envsize, "KRB5CCNAME",
1296                     s->authctxt->krb5_ticket_file);
1297 #endif
1298 #ifdef USE_PAM
1299         /* Pull in any environment variables that may have been set by PAM. */
1300         do_pam_environment(&env, &envsize);
1301 #endif /* USE_PAM */
1302
1303         if (auth_get_socket_name() != NULL)
1304                 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1305                               auth_get_socket_name());
1306
1307         /* read $HOME/.ssh/environment. */
1308         if (!options.use_login) {
1309                 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1310                     pw->pw_dir);
1311                 read_environment_file(&env, &envsize, buf);
1312         }
1313         if (debug_flag) {
1314                 /* dump the environment */
1315                 fprintf(stderr, "Environment:\n");
1316                 for (i = 0; env[i]; i++)
1317                         fprintf(stderr, "  %.200s\n", env[i]);
1318         }
1319         /* we have to stash the hostname before we close our socket. */
1320         if (options.use_login)
1321                 hostname = get_remote_name_or_ip(utmp_len,
1322                     options.reverse_mapping_check);
1323         /*
1324          * Close the connection descriptors; note that this is the child, and
1325          * the server will still have the socket open, and it is important
1326          * that we do not shutdown it.  Note that the descriptors cannot be
1327          * closed before building the environment, as we call
1328          * get_remote_ipaddr there.
1329          */
1330         if (packet_get_connection_in() == packet_get_connection_out())
1331                 close(packet_get_connection_in());
1332         else {
1333                 close(packet_get_connection_in());
1334                 close(packet_get_connection_out());
1335         }
1336         /*
1337          * Close all descriptors related to channels.  They will still remain
1338          * open in the parent.
1339          */
1340         /* XXX better use close-on-exec? -markus */
1341         channel_close_all();
1342
1343         /*
1344          * Close any extra file descriptors.  Note that there may still be
1345          * descriptors left by system functions.  They will be closed later.
1346          */
1347         endpwent();
1348
1349         /*
1350          * Close any extra open file descriptors so that we don\'t have them
1351          * hanging around in clients.  Note that we want to do this after
1352          * initgroups, because at least on Solaris 2.3 it leaves file
1353          * descriptors open.
1354          */
1355         for (i = 3; i < 64; i++)
1356                 close(i);
1357
1358         /*
1359          * Must take new environment into use so that .ssh/rc, /etc/sshrc and
1360          * xauth are run in the proper environment.
1361          */
1362         environ = env;
1363
1364 #ifdef AFS
1365         /* Try to get AFS tokens for the local cell. */
1366         if (k_hasafs()) {
1367                 char cell[64];
1368
1369                 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1370                         krb_afslog(cell, 0);
1371
1372                 krb_afslog(0, 0);
1373         }
1374 #endif /* AFS */
1375
1376         /* Change current directory to the user\'s home directory. */
1377         if (chdir(pw->pw_dir) < 0) {
1378                 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1379                     pw->pw_dir, strerror(errno));
1380 #ifdef HAVE_LOGIN_CAP
1381                 if (login_getcapbool(lc, "requirehome", 0))
1382                         exit(1);
1383 #endif
1384         }
1385
1386         /*
1387          * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
1388          * in this order).
1389          */
1390         if (!options.use_login) {
1391                 /* ignore _PATH_SSH_USER_RC for subsystems */
1392                 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1393                         snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1394                             shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1395                         if (debug_flag)
1396                                 fprintf(stderr, "Running %s\n", cmd);
1397                         f = popen(cmd, "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_USER_RC);
1406                 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1407                         if (debug_flag)
1408                                 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1409                                     _PATH_SSH_SYSTEM_RC);
1410                         f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1411                         if (f) {
1412                                 if (do_xauth)
1413                                         fprintf(f, "%s %s\n", s->auth_proto,
1414                                             s->auth_data);
1415                                 pclose(f);
1416                         } else
1417                                 fprintf(stderr, "Could not run %s\n",
1418                                     _PATH_SSH_SYSTEM_RC);
1419                 } else if (do_xauth && options.xauth_location != NULL) {
1420                         /* Add authority data to .Xauthority if appropriate. */
1421                         char *screen = strchr(s->display, ':');
1422
1423                         if (debug_flag) {
1424                                 fprintf(stderr,
1425                                     "Running %.100s add "
1426                                     "%.100s %.100s %.100s\n",
1427                                     options.xauth_location, s->display,
1428                                     s->auth_proto, s->auth_data);
1429                                 if (screen != NULL)
1430                                         fprintf(stderr,
1431                                             "Adding %.*s/unix%s %s %s\n",
1432                                             (int)(screen - s->display),
1433                                             s->display, screen,
1434                                             s->auth_proto, s->auth_data);
1435                         }
1436                         snprintf(cmd, sizeof cmd, "%s -q -",
1437                             options.xauth_location);
1438                         f = popen(cmd, "w");
1439                         if (f) {
1440                                 fprintf(f, "add %s %s %s\n", s->display,
1441                                     s->auth_proto, s->auth_data);
1442                                 if (screen != NULL)
1443                                         fprintf(f, "add %.*s/unix%s %s %s\n",
1444                                             (int)(screen - s->display),
1445                                             s->display, screen,
1446                                             s->auth_proto,
1447                                             s->auth_data);
1448                                 pclose(f);
1449                         } else {
1450                                 fprintf(stderr, "Could not run %s\n",
1451                                     cmd);
1452                         }
1453                 }
1454                 /* Get the last component of the shell name. */
1455                 cp = strrchr(shell, '/');
1456                 if (cp)
1457                         cp++;
1458                 else
1459                         cp = shell;
1460         }
1461
1462         /* restore SIGPIPE for child */
1463         signal(SIGPIPE,  SIG_DFL);
1464
1465         /*
1466          * If we have no command, execute the shell.  In this case, the shell
1467          * name to be passed in argv[0] is preceded by '-' to indicate that
1468          * this is a login shell.
1469          */
1470         if (!command) {
1471                 if (!options.use_login) {
1472                         char buf[256];
1473
1474                         /* Start the shell.  Set initial character to '-'. */
1475                         buf[0] = '-';
1476                         strncpy(buf + 1, cp, sizeof(buf) - 1);
1477                         buf[sizeof(buf) - 1] = 0;
1478
1479                         /* Execute the shell. */
1480                         argv[0] = buf;
1481                         argv[1] = NULL;
1482                         execve(shell, argv, env);
1483
1484                         /* Executing the shell failed. */
1485                         perror(shell);
1486                         exit(1);
1487
1488                 } else {
1489                         /* Launch login(1). */
1490
1491                         execl(LOGIN_PROGRAM, "login", "-h", hostname,
1492 #ifdef LOGIN_NEEDS_TERM
1493                              s->term? s->term : "unknown",
1494 #endif
1495                              "-p", "-f", "--", pw->pw_name, (char *)NULL);
1496
1497                         /* Login couldn't be executed, die. */
1498
1499                         perror("login");
1500                         exit(1);
1501                 }
1502         }
1503         /*
1504          * Execute the command using the user's shell.  This uses the -c
1505          * option to execute the command.
1506          */
1507         argv[0] = (char *) cp;
1508         argv[1] = "-c";
1509         argv[2] = (char *) command;
1510         argv[3] = NULL;
1511         execve(shell, argv, env);
1512         perror(shell);
1513         exit(1);
1514 }
1515
1516 Session *
1517 session_new(void)
1518 {
1519         int i;
1520         static int did_init = 0;
1521         if (!did_init) {
1522                 debug("session_new: init");
1523                 for(i = 0; i < MAX_SESSIONS; i++) {
1524                         sessions[i].used = 0;
1525                 }
1526                 did_init = 1;
1527         }
1528         for(i = 0; i < MAX_SESSIONS; i++) {
1529                 Session *s = &sessions[i];
1530                 if (! s->used) {
1531                         memset(s, 0, sizeof(*s));
1532                         s->chanid = -1;
1533                         s->ptyfd = -1;
1534                         s->ttyfd = -1;
1535                         s->used = 1;
1536                         s->self = i;
1537                         debug("session_new: session %d", i);
1538                         return s;
1539                 }
1540         }
1541         return NULL;
1542 }
1543
1544 static void
1545 session_dump(void)
1546 {
1547         int i;
1548         for(i = 0; i < MAX_SESSIONS; i++) {
1549                 Session *s = &sessions[i];
1550                 debug("dump: used %d session %d %p channel %d pid %d",
1551                     s->used,
1552                     s->self,
1553                     s,
1554                     s->chanid,
1555                     s->pid);
1556         }
1557 }
1558
1559 int
1560 session_open(Authctxt *authctxt, int chanid)
1561 {
1562         Session *s = session_new();
1563         debug("session_open: channel %d", chanid);
1564         if (s == NULL) {
1565                 error("no more sessions");
1566                 return 0;
1567         }
1568         s->authctxt = authctxt;
1569         s->pw = authctxt->pw;
1570         if (s->pw == NULL)
1571                 fatal("no user for session %d", s->self);
1572         debug("session_open: session %d: link with channel %d", s->self, chanid);
1573         s->chanid = chanid;
1574         return 1;
1575 }
1576
1577 static Session *
1578 session_by_channel(int id)
1579 {
1580         int i;
1581         for(i = 0; i < MAX_SESSIONS; i++) {
1582                 Session *s = &sessions[i];
1583                 if (s->used && s->chanid == id) {
1584                         debug("session_by_channel: session %d channel %d", i, id);
1585                         return s;
1586                 }
1587         }
1588         debug("session_by_channel: unknown channel %d", id);
1589         session_dump();
1590         return NULL;
1591 }
1592
1593 static Session *
1594 session_by_pid(pid_t pid)
1595 {
1596         int i;
1597         debug("session_by_pid: pid %d", pid);
1598         for(i = 0; i < MAX_SESSIONS; i++) {
1599                 Session *s = &sessions[i];
1600                 if (s->used && s->pid == pid)
1601                         return s;
1602         }
1603         error("session_by_pid: unknown pid %d", pid);
1604         session_dump();
1605         return NULL;
1606 }
1607
1608 static int
1609 session_window_change_req(Session *s)
1610 {
1611         s->col = packet_get_int();
1612         s->row = packet_get_int();
1613         s->xpixel = packet_get_int();
1614         s->ypixel = packet_get_int();
1615         packet_done();
1616         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1617         return 1;
1618 }
1619
1620 static int
1621 session_pty_req(Session *s)
1622 {
1623         u_int len;
1624         int n_bytes;
1625
1626         if (no_pty_flag) {
1627                 debug("Allocating a pty not permitted for this authentication.");
1628                 return 0;
1629         }
1630         if (s->ttyfd != -1) {
1631                 packet_disconnect("Protocol error: you already have a pty.");
1632                 return 0;
1633         }
1634
1635         s->term = packet_get_string(&len);
1636
1637         if (compat20) {
1638                 s->col = packet_get_int();
1639                 s->row = packet_get_int();
1640         } else {
1641                 s->row = packet_get_int();
1642                 s->col = packet_get_int();
1643         }
1644         s->xpixel = packet_get_int();
1645         s->ypixel = packet_get_int();
1646
1647         if (strcmp(s->term, "") == 0) {
1648                 xfree(s->term);
1649                 s->term = NULL;
1650         }
1651
1652         /* Allocate a pty and open it. */
1653         debug("Allocating pty.");
1654         if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1655                 if (s->term)
1656                         xfree(s->term);
1657                 s->term = NULL;
1658                 s->ptyfd = -1;
1659                 s->ttyfd = -1;
1660                 error("session_pty_req: session %d alloc failed", s->self);
1661                 return 0;
1662         }
1663         debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1664
1665         /* for SSH1 the tty modes length is not given */
1666         if (!compat20)
1667                 n_bytes = packet_remaining();
1668         tty_parse_modes(s->ttyfd, &n_bytes);
1669
1670         /*
1671          * Add a cleanup function to clear the utmp entry and record logout
1672          * time in case we call fatal() (e.g., the connection gets closed).
1673          */
1674         fatal_add_cleanup(session_pty_cleanup, (void *)s);
1675         pty_setowner(s->pw, s->tty);
1676
1677         /* Set window size from the packet. */
1678         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1679
1680         packet_done();
1681         session_proctitle(s);
1682         return 1;
1683 }
1684
1685 static int
1686 session_subsystem_req(Session *s)
1687 {
1688         struct stat st;
1689         u_int len;
1690         int success = 0;
1691         char *cmd, *subsys = packet_get_string(&len);
1692         int i;
1693
1694         packet_done();
1695         log("subsystem request for %s", subsys);
1696
1697         for (i = 0; i < options.num_subsystems; i++) {
1698                 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1699                         cmd = options.subsystem_command[i];
1700                         if (stat(cmd, &st) < 0) {
1701                                 error("subsystem: cannot stat %s: %s", cmd,
1702                                     strerror(errno));
1703                                 break;
1704                         }
1705                         debug("subsystem: exec() %s", cmd);
1706                         s->is_subsystem = 1;
1707                         do_exec(s, cmd);
1708                         success = 1;
1709                 }
1710         }
1711
1712         if (!success)
1713                 log("subsystem request for %s failed, subsystem not found",
1714                     subsys);
1715
1716         xfree(subsys);
1717         return success;
1718 }
1719
1720 static int
1721 session_x11_req(Session *s)
1722 {
1723         int success;
1724
1725         s->single_connection = packet_get_char();
1726         s->auth_proto = packet_get_string(NULL);
1727         s->auth_data = packet_get_string(NULL);
1728         s->screen = packet_get_int();
1729         packet_done();
1730
1731         success = session_setup_x11fwd(s);
1732         if (!success) {
1733                 xfree(s->auth_proto);
1734                 xfree(s->auth_data);
1735                 s->auth_proto = NULL;
1736                 s->auth_data = NULL;
1737         }
1738         return success;
1739 }
1740
1741 static int
1742 session_shell_req(Session *s)
1743 {
1744         packet_done();
1745         do_exec(s, NULL);
1746         return 1;
1747 }
1748
1749 static int
1750 session_exec_req(Session *s)
1751 {
1752         u_int len;
1753         char *command = packet_get_string(&len);
1754         packet_done();
1755         do_exec(s, command);
1756         xfree(command);
1757         return 1;
1758 }
1759
1760 static int
1761 session_auth_agent_req(Session *s)
1762 {
1763         static int called = 0;
1764         packet_done();
1765         if (no_agent_forwarding_flag) {
1766                 debug("session_auth_agent_req: no_agent_forwarding_flag");
1767                 return 0;
1768         }
1769         if (called) {
1770                 return 0;
1771         } else {
1772                 called = 1;
1773                 return auth_input_request_forwarding(s->pw);
1774         }
1775 }
1776
1777 void
1778 session_input_channel_req(int id, void *arg)
1779 {
1780         u_int len;
1781         int reply;
1782         int success = 0;
1783         char *rtype;
1784         Session *s;
1785         Channel *c;
1786
1787         rtype = packet_get_string(&len);
1788         reply = packet_get_char();
1789
1790         s = session_by_channel(id);
1791         if (s == NULL)
1792                 fatal("session_input_channel_req: channel %d: no session", id);
1793         c = channel_lookup(id);
1794         if (c == NULL)
1795                 fatal("session_input_channel_req: channel %d: bad channel", id);
1796
1797         debug("session_input_channel_req: session %d channel %d request %s reply %d",
1798             s->self, id, rtype, reply);
1799
1800         /*
1801          * a session is in LARVAL state until a shell, a command
1802          * or a subsystem is executed
1803          */
1804         if (c->type == SSH_CHANNEL_LARVAL) {
1805                 if (strcmp(rtype, "shell") == 0) {
1806                         success = session_shell_req(s);
1807                 } else if (strcmp(rtype, "exec") == 0) {
1808                         success = session_exec_req(s);
1809                 } else if (strcmp(rtype, "pty-req") == 0) {
1810                         success =  session_pty_req(s);
1811                 } else if (strcmp(rtype, "x11-req") == 0) {
1812                         success = session_x11_req(s);
1813                 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1814                         success = session_auth_agent_req(s);
1815                 } else if (strcmp(rtype, "subsystem") == 0) {
1816                         success = session_subsystem_req(s);
1817                 }
1818         }
1819         if (strcmp(rtype, "window-change") == 0) {
1820                 success = session_window_change_req(s);
1821         }
1822
1823         if (reply) {
1824                 packet_start(success ?
1825                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1826                 packet_put_int(c->remote_id);
1827                 packet_send();
1828         }
1829         xfree(rtype);
1830 }
1831
1832 void
1833 session_set_fds(Session *s, int fdin, int fdout, int fderr)
1834 {
1835         if (!compat20)
1836                 fatal("session_set_fds: called for proto != 2.0");
1837         /*
1838          * now that have a child and a pipe to the child,
1839          * we can activate our channel and register the fd's
1840          */
1841         if (s->chanid == -1)
1842                 fatal("no channel for session %d", s->self);
1843         channel_set_fds(s->chanid,
1844             fdout, fdin, fderr,
1845             fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1846             1);
1847 }
1848
1849 /*
1850  * Function to perform pty cleanup. Also called if we get aborted abnormally
1851  * (e.g., due to a dropped connection).
1852  */
1853 static void
1854 session_pty_cleanup(void *session)
1855 {
1856         Session *s = session;
1857
1858         if (s == NULL) {
1859                 error("session_pty_cleanup: no session");
1860                 return;
1861         }
1862         if (s->ttyfd == -1)
1863                 return;
1864
1865         debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1866
1867         /* Record that the user has logged out. */
1868         if (s->pid != 0)
1869                 record_logout(s->pid, s->tty);
1870
1871         /* Release the pseudo-tty. */
1872         pty_release(s->tty);
1873
1874         /*
1875          * Close the server side of the socket pairs.  We must do this after
1876          * the pty cleanup, so that another process doesn't get this pty
1877          * while we're still cleaning up.
1878          */
1879         if (close(s->ptymaster) < 0)
1880                 error("close(s->ptymaster): %s", strerror(errno));
1881
1882         /* unlink pty from session */
1883         s->ttyfd = -1;
1884 }
1885
1886 static void
1887 session_exit_message(Session *s, int status)
1888 {
1889         Channel *c;
1890         if (s == NULL)
1891                 fatal("session_close: no session");
1892         c = channel_lookup(s->chanid);
1893         if (c == NULL)
1894                 fatal("session_exit_message: session %d: no channel %d",
1895                     s->self, s->chanid);
1896         debug("session_exit_message: session %d channel %d pid %d",
1897             s->self, s->chanid, s->pid);
1898
1899         if (WIFEXITED(status)) {
1900                 channel_request_start(s->chanid,
1901                     "exit-status", 0);
1902                 packet_put_int(WEXITSTATUS(status));
1903                 packet_send();
1904         } else if (WIFSIGNALED(status)) {
1905                 channel_request_start(s->chanid,
1906                     "exit-signal", 0);
1907                 packet_put_int(WTERMSIG(status));
1908 #ifdef WCOREDUMP
1909                 packet_put_char(WCOREDUMP(status));
1910 #else /* WCOREDUMP */
1911                 packet_put_char(0);
1912 #endif /* WCOREDUMP */
1913                 packet_put_cstring("");
1914                 packet_put_cstring("");
1915                 packet_send();
1916         } else {
1917                 /* Some weird exit cause.  Just exit. */
1918                 packet_disconnect("wait returned status %04x.", status);
1919         }
1920
1921         /* disconnect channel */
1922         debug("session_exit_message: release channel %d", s->chanid);
1923         channel_cancel_cleanup(s->chanid);
1924         /*
1925          * emulate a write failure with 'chan_write_failed', nobody will be
1926          * interested in data we write.
1927          * Note that we must not call 'chan_read_failed', since there could
1928          * be some more data waiting in the pipe.
1929          */
1930         if (c->ostate != CHAN_OUTPUT_CLOSED)
1931                 chan_write_failed(c);
1932         s->chanid = -1;
1933 }
1934
1935 static void
1936 session_close(Session *s)
1937 {
1938         debug("session_close: session %d pid %d", s->self, s->pid);
1939         if (s->ttyfd != -1) {
1940                 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1941                 session_pty_cleanup(s);
1942         }
1943         if (s->term)
1944                 xfree(s->term);
1945         if (s->display)
1946                 xfree(s->display);
1947         if (s->auth_data)
1948                 xfree(s->auth_data);
1949         if (s->auth_proto)
1950                 xfree(s->auth_proto);
1951         s->used = 0;
1952         session_proctitle(s);
1953 }
1954
1955 void
1956 session_close_by_pid(pid_t pid, int status)
1957 {
1958         Session *s = session_by_pid(pid);
1959         if (s == NULL) {
1960                 debug("session_close_by_pid: no session for pid %d", pid);
1961                 return;
1962         }
1963         if (s->chanid != -1)
1964                 session_exit_message(s, status);
1965         session_close(s);
1966 }
1967
1968 /*
1969  * this is called when a channel dies before
1970  * the session 'child' itself dies
1971  */
1972 void
1973 session_close_by_channel(int id, void *arg)
1974 {
1975         Session *s = session_by_channel(id);
1976         if (s == NULL) {
1977                 debug("session_close_by_channel: no session for id %d", id);
1978                 return;
1979         }
1980         debug("session_close_by_channel: channel %d child %d", id, s->pid);
1981         if (s->pid != 0) {
1982                 debug("session_close_by_channel: channel %d: has child", id);
1983                 /*
1984                  * delay detach of session, but release pty, since
1985                  * the fd's to the child are already closed
1986                  */
1987                 if (s->ttyfd != -1) {
1988                         fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1989                         session_pty_cleanup(s);
1990                 }
1991                 return;
1992         }
1993         /* detach by removing callback */
1994         channel_cancel_cleanup(s->chanid);
1995         s->chanid = -1;
1996         session_close(s);
1997 }
1998
1999 void
2000 session_destroy_all(void)
2001 {
2002         int i;
2003         for(i = 0; i < MAX_SESSIONS; i++) {
2004                 Session *s = &sessions[i];
2005                 if (s->used)
2006                         session_close(s);
2007         }
2008 }
2009
2010 static char *
2011 session_tty_list(void)
2012 {
2013         static char buf[1024];
2014         int i;
2015         buf[0] = '\0';
2016         for(i = 0; i < MAX_SESSIONS; i++) {
2017                 Session *s = &sessions[i];
2018                 if (s->used && s->ttyfd != -1) {
2019                         if (buf[0] != '\0')
2020                                 strlcat(buf, ",", sizeof buf);
2021                         strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2022                 }
2023         }
2024         if (buf[0] == '\0')
2025                 strlcpy(buf, "notty", sizeof buf);
2026         return buf;
2027 }
2028
2029 void
2030 session_proctitle(Session *s)
2031 {
2032         if (s->pw == NULL)
2033                 error("no user for session %d", s->self);
2034         else
2035                 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2036 }
2037
2038 int
2039 session_setup_x11fwd(Session *s)
2040 {
2041         struct stat st;
2042
2043         if (no_x11_forwarding_flag) {
2044                 packet_send_debug("X11 forwarding disabled in user configuration file.");
2045                 return 0;
2046         }
2047         if (!options.x11_forwarding) {
2048                 debug("X11 forwarding disabled in server configuration file.");
2049                 return 0;
2050         }
2051         if (!options.xauth_location ||
2052             (stat(options.xauth_location, &st) == -1)) {
2053                 packet_send_debug("No xauth program; cannot forward with spoofing.");
2054                 return 0;
2055         }
2056         if (options.use_login) {
2057                 packet_send_debug("X11 forwarding disabled; "
2058                     "not compatible with UseLogin=yes.");
2059                 return 0;
2060         }
2061         if (s->display != NULL) {
2062                 debug("X11 display already set.");
2063                 return 0;
2064         }
2065         s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
2066         if (s->display == NULL) {
2067                 debug("x11_create_display_inet failed.");
2068                 return 0;
2069         }
2070         return 1;
2071 }
2072
2073 static void
2074 do_authenticated2(Authctxt *authctxt)
2075 {
2076         server_loop2(authctxt);
2077 }