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 1.117 2001/12/28 14:50:54 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         int     display_number;
 112         char    *display;
 113         int     screen;
 114         char    *auth_display[2];
 115         char    *auth_proto;
 116         char    *auth_data;
 117         int     single_connection;
 118         /* proto 2 */
 119         int     chanid;
 120         int     is_subsystem;
 121 };
 122
 123 /* func */
 124
 125 Session *session_new(void);
 126 void    session_set_fds(Session *, int, int, int);
 127 static void     session_pty_cleanup(void *);
 128 void    session_proctitle(Session *);
 129 int     session_setup_x11fwd(Session *);
 130 void    do_exec_pty(Session *, const char *);
 131 void    do_exec_no_pty(Session *, const char *);
 132 void    do_exec(Session *, const char *);
 133 void    do_login(Session *, const char *);
 134 #ifdef LOGIN_NEEDS_UTMPX
 135 static void     do_pre_login(Session *s);
 136 #endif
 137 void    do_child(Session *, const char *);
 138 void    do_motd(void);
 139 int     check_quietlogin(Session *, const char *);
 140
 141 static void do_authenticated1(Authctxt *);
 142 static void do_authenticated2(Authctxt *);
 143
 144 static void session_close(Session *);
 145 static int session_pty_req(Session *);
 146
 147 /* import */
 148 extern ServerOptions options;
 149 extern char *__progname;
 150 extern int log_stderr;
 151 extern int debug_flag;
 152 extern u_int utmp_len;
 153 extern int startup_pipe;
 154 extern void destroy_sensitive_data(void);
 155
 156 /* original command from peer. */
 157 const char *original_command = NULL;
 158
 159 /* data */
 160 #define MAX_SESSIONS 10
 161 Session sessions[MAX_SESSIONS];
 162
 163 #ifdef WITH_AIXAUTHENTICATE
 164 char *aixloginmsg;
 165 #endif /* WITH_AIXAUTHENTICATE */
 166
 167 #ifdef HAVE_LOGIN_CAP
 168 static login_cap_t *lc;
 169 #endif
 170
 171 void
 172 do_authenticated(Authctxt *authctxt)
 173 {
 174         /*
 175          * Cancel the alarm we set to limit the time taken for
 176          * authentication.
 177          */
 178         alarm(0);
 179         if (startup_pipe != -1) {
 180                 close(startup_pipe);
 181                 startup_pipe = -1;
 182         }
 183 #if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
 184         if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
 185                 error("unable to get login class");
 186                 return;
 187         }
 188 #ifdef BSD_AUTH
 189         if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
 190                 packet_disconnect("Approval failure for %s",
 191                     authctxt->pw->pw_name);
 192         }
 193 #endif
 194 #endif
 195 #ifdef WITH_AIXAUTHENTICATE
 196         /* We don't have a pty yet, so just label the line as "ssh" */
 197         if (loginsuccess(authctxt->user,
 198             get_canonical_hostname(options.reverse_mapping_check),
 199             "ssh", &aixloginmsg) < 0)
 200                 aixloginmsg = NULL;
 201 #endif /* WITH_AIXAUTHENTICATE */
 202
 203         /* setup the channel layer */
 204         if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
 205                 channel_permit_all_opens();
 206
 207         if (compat20)
 208                 do_authenticated2(authctxt);
 209         else
 210                 do_authenticated1(authctxt);
 211
 212         /* remove agent socket */
 213         if (auth_get_socket_name())
 214                 auth_sock_cleanup_proc(authctxt->pw);
 215 #ifdef KRB4
 216         if (options.kerberos_ticket_cleanup)
 217                 krb4_cleanup_proc(authctxt);
 218 #endif
 219 #ifdef KRB5
 220         if (options.kerberos_ticket_cleanup)
 221                 krb5_cleanup_proc(authctxt);
 222 #endif
 223 }
 224
 225 /*
 226  * Prepares for an interactive session.  This is called after the user has
 227  * been successfully authenticated.  During this message exchange, pseudo
 228  * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
 229  * are requested, etc.
 230  */
 231 static void
 232 do_authenticated1(Authctxt *authctxt)
 233 {
 234         Session *s;
 235         char *command;
 236         int success, type, screen_flag;
 237         int compression_level = 0, enable_compression_after_reply = 0;
 238         u_int proto_len, data_len, dlen;
 239
 240         s = session_new();
 241         s->authctxt = authctxt;
 242         s->pw = authctxt->pw;
 243
 244         /*
 245          * We stay in this loop until the client requests to execute a shell
 246          * or a command.
 247          */
 248         for (;;) {
 249                 success = 0;
 250
 251                 /* Get a packet from the client. */
 252                 type = packet_read();
 253
 254                 /* Process the packet. */
 255                 switch (type) {
 256                 case SSH_CMSG_REQUEST_COMPRESSION:
 257                         compression_level = packet_get_int();
 258                         packet_check_eom();
 259                         if (compression_level < 1 || compression_level > 9) {
 260                                 packet_send_debug("Received illegal compression level %d.",
 261                                     compression_level);
 262                                 break;
 263                         }
 264                         /* Enable compression after we have responded with SUCCESS. */
 265                         enable_compression_after_reply = 1;
 266                         success = 1;
 267                         break;
 268
 269                 case SSH_CMSG_REQUEST_PTY:
 270                         success = session_pty_req(s);
 271                         break;
 272
 273                 case SSH_CMSG_X11_REQUEST_FORWARDING:
 274                         s->auth_proto = packet_get_string(&proto_len);
 275                         s->auth_data = packet_get_string(&data_len);
 276
 277                         screen_flag = packet_get_protocol_flags() &
 278                             SSH_PROTOFLAG_SCREEN_NUMBER;
 279                         debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
 280
 281                         if (packet_remaining() == 4) {
 282                                 if (!screen_flag)
 283                                         debug2("Buggy client: "
 284                                             "X11 screen flag missing");
 285                                 s->screen = packet_get_int();
 286                         } else {
 287                                 s->screen = 0;
 288                         }
 289                         packet_check_eom();
 290                         success = session_setup_x11fwd(s);
 291                         if (!success) {
 292                                 xfree(s->auth_proto);
 293                                 xfree(s->auth_data);
 294                                 s->auth_proto = NULL;
 295                                 s->auth_data = NULL;
 296                         }
 297                         break;
 298
 299                 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
 300                         if (no_agent_forwarding_flag || compat13) {
 301                                 debug("Authentication agent forwarding not permitted for this authentication.");
 302                                 break;
 303                         }
 304                         debug("Received authentication agent forwarding request.");
 305                         success = auth_input_request_forwarding(s->pw);
 306                         break;
 307
 308                 case SSH_CMSG_PORT_FORWARD_REQUEST:
 309                         if (no_port_forwarding_flag) {
 310                                 debug("Port forwarding not permitted for this authentication.");
 311                                 break;
 312                         }
 313                         if (!options.allow_tcp_forwarding) {
 314                                 debug("Port forwarding not permitted.");
 315                                 break;
 316                         }
 317                         debug("Received TCP/IP port forwarding request.");
 318                         channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
 319                         success = 1;
 320                         break;
 321
 322                 case SSH_CMSG_MAX_PACKET_SIZE:
 323                         if (packet_set_maxsize(packet_get_int()) > 0)
 324                                 success = 1;
 325                         break;
 326
 327 #if defined(AFS) || defined(KRB5)
 328                 case SSH_CMSG_HAVE_KERBEROS_TGT:
 329                         if (!options.kerberos_tgt_passing) {
 330                                 verbose("Kerberos TGT passing disabled.");
 331                         } else {
 332                                 char *kdata = packet_get_string(&dlen);
 333                                 packet_check_eom();
 334
 335                                 /* XXX - 0x41, see creds_to_radix version */
 336                                 if (kdata[0] != 0x41) {
 337 #ifdef KRB5
 338                                         krb5_data tgt;
 339                                         tgt.data = kdata;
 340                                         tgt.length = dlen;
 341
 342                                         if (auth_krb5_tgt(s->authctxt, &tgt))
 343                                                 success = 1;
 344                                         else
 345                                                 verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
 346 #endif /* KRB5 */
 347                                 } else {
 348 #ifdef AFS
 349                                         if (auth_krb4_tgt(s->authctxt, kdata))
 350                                                 success = 1;
 351                                         else
 352                                                 verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
 353 #endif /* AFS */
 354                                 }
 355                                 xfree(kdata);
 356                         }
 357                         break;
 358 #endif /* AFS || KRB5 */
 359
 360 #ifdef AFS
 361                 case SSH_CMSG_HAVE_AFS_TOKEN:
 362                         if (!options.afs_token_passing || !k_hasafs()) {
 363                                 verbose("AFS token passing disabled.");
 364                         } else {
 365                                 /* Accept AFS token. */
 366                                 char *token = packet_get_string(&dlen);
 367                                 packet_check_eom();
 368
 369                                 if (auth_afs_token(s->authctxt, token))
 370                                         success = 1;
 371                                 else
 372                                         verbose("AFS token refused for %.100s",
 373                                             s->authctxt->user);
 374                                 xfree(token);
 375                         }
 376                         break;
 377 #endif /* AFS */
 378
 379                 case SSH_CMSG_EXEC_SHELL:
 380                 case SSH_CMSG_EXEC_CMD:
 381                         if (type == SSH_CMSG_EXEC_CMD) {
 382                                 command = packet_get_string(&dlen);
 383                                 debug("Exec command '%.500s'", command);
 384                                 do_exec(s, command);
 385                                 xfree(command);
 386                         } else {
 387                                 do_exec(s, NULL);
 388                         }
 389                         packet_check_eom();
 390                         session_close(s);
 391                         return;
 392
 393                 default:
 394                         /*
 395                          * Any unknown messages in this phase are ignored,
 396                          * and a failure message is returned.
 397                          */
 398                         log("Unknown packet type received after authentication: %d", type);
 399                 }
 400                 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
 401                 packet_send();
 402                 packet_write_wait();
 403
 404                 /* Enable compression now that we have replied if appropriate. */
 405                 if (enable_compression_after_reply) {
 406                         enable_compression_after_reply = 0;
 407                         packet_start_compression(compression_level);
 408                 }
 409         }
 410 }
 411
 412 /*
 413  * This is called to fork and execute a command when we have no tty.  This
 414  * will call do_child from the child, and server_loop from the parent after
 415  * setting up file descriptors and such.
 416  */
 417 void
 418 do_exec_no_pty(Session *s, const char *command)
 419 {
 420         int pid;
 421
 422 #ifdef USE_PIPES
 423         int pin[2], pout[2], perr[2];
 424         /* Allocate pipes for communicating with the program. */
 425         if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
 426                 packet_disconnect("Could not create pipes: %.100s",
 427                                   strerror(errno));
 428 #else /* USE_PIPES */
 429         int inout[2], err[2];
 430         /* Uses socket pairs to communicate with the program. */
 431         if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
 432             socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
 433                 packet_disconnect("Could not create socket pairs: %.100s",
 434                                   strerror(errno));
 435 #endif /* USE_PIPES */
 436         if (s == NULL)
 437                 fatal("do_exec_no_pty: no session");
 438
 439         session_proctitle(s);
 440
 441 #if defined(USE_PAM)
 442         do_pam_session(s->pw->pw_name, NULL);
 443         do_pam_setcred(1);
 444         if (is_pam_password_change_required())
 445                 packet_disconnect("Password change required but no "
 446                     "TTY available");
 447 #endif /* USE_PAM */
 448
 449         /* Fork the child. */
 450         if ((pid = fork()) == 0) {
 451                 /* Child.  Reinitialize the log since the pid has changed. */
 452                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 453
 454                 /*
 455                  * Create a new session and process group since the 4.4BSD
 456                  * setlogin() affects the entire process group.
 457                  */
 458                 if (setsid() < 0)
 459                         error("setsid failed: %.100s", strerror(errno));
 460
 461 #ifdef USE_PIPES
 462                 /*
 463                  * Redirect stdin.  We close the parent side of the socket
 464                  * pair, and make the child side the standard input.
 465                  */
 466                 close(pin[1]);
 467                 if (dup2(pin[0], 0) < 0)
 468                         perror("dup2 stdin");
 469                 close(pin[0]);
 470
 471                 /* Redirect stdout. */
 472                 close(pout[0]);
 473                 if (dup2(pout[1], 1) < 0)
 474                         perror("dup2 stdout");
 475                 close(pout[1]);
 476
 477                 /* Redirect stderr. */
 478                 close(perr[0]);
 479                 if (dup2(perr[1], 2) < 0)
 480                         perror("dup2 stderr");
 481                 close(perr[1]);
 482 #else /* USE_PIPES */
 483                 /*
 484                  * Redirect stdin, stdout, and stderr.  Stdin and stdout will
 485                  * use the same socket, as some programs (particularly rdist)
 486                  * seem to depend on it.
 487                  */
 488                 close(inout[1]);
 489                 close(err[1]);
 490                 if (dup2(inout[0], 0) < 0)      /* stdin */
 491                         perror("dup2 stdin");
 492                 if (dup2(inout[0], 1) < 0)      /* stdout.  Note: same socket as stdin. */
 493                         perror("dup2 stdout");
 494                 if (dup2(err[0], 2) < 0)        /* stderr */
 495                         perror("dup2 stderr");
 496 #endif /* USE_PIPES */
 497
 498                 /* Do processing for the child (exec command etc). */
 499                 do_child(s, command);
 500                 /* NOTREACHED */
 501         }
 502 #ifdef HAVE_CYGWIN
 503         if (is_winnt)
 504                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 505 #endif
 506         if (pid < 0)
 507                 packet_disconnect("fork failed: %.100s", strerror(errno));
 508         s->pid = pid;
 509         /* Set interactive/non-interactive mode. */
 510         packet_set_interactive(s->display != NULL);
 511 #ifdef USE_PIPES
 512         /* We are the parent.  Close the child sides of the pipes. */
 513         close(pin[0]);
 514         close(pout[1]);
 515         close(perr[1]);
 516
 517         if (compat20) {
 518                 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
 519         } else {
 520                 /* Enter the interactive session. */
 521                 server_loop(pid, pin[1], pout[0], perr[0]);
 522                 /* server_loop has closed pin[1], pout[0], and perr[0]. */
 523         }
 524 #else /* USE_PIPES */
 525         /* We are the parent.  Close the child sides of the socket pairs. */
 526         close(inout[0]);
 527         close(err[0]);
 528
 529         /*
 530          * Enter the interactive session.  Note: server_loop must be able to
 531          * handle the case that fdin and fdout are the same.
 532          */
 533         if (compat20) {
 534                 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
 535         } else {
 536                 server_loop(pid, inout[1], inout[1], err[1]);
 537                 /* server_loop has closed inout[1] and err[1]. */
 538         }
 539 #endif /* USE_PIPES */
 540 }
 541
 542 /*
 543  * This is called to fork and execute a command when we have a tty.  This
 544  * will call do_child from the child, and server_loop from the parent after
 545  * setting up file descriptors, controlling tty, updating wtmp, utmp,
 546  * lastlog, and other such operations.
 547  */
 548 void
 549 do_exec_pty(Session *s, const char *command)
 550 {
 551         int fdout, ptyfd, ttyfd, ptymaster;
 552         pid_t pid;
 553
 554         if (s == NULL)
 555                 fatal("do_exec_pty: no session");
 556         ptyfd = s->ptyfd;
 557         ttyfd = s->ttyfd;
 558
 559 #if defined(USE_PAM)
 560         do_pam_session(s->pw->pw_name, s->tty);
 561         do_pam_setcred(1);
 562 #endif
 563
 564         /* Fork the child. */
 565         if ((pid = fork()) == 0) {
 566
 567                 /* Child.  Reinitialize the log because the pid has changed. */
 568                 log_init(__progname, options.log_level, options.log_facility, log_stderr);
 569                 /* Close the master side of the pseudo tty. */
 570                 close(ptyfd);
 571
 572                 /* Make the pseudo tty our controlling tty. */
 573                 pty_make_controlling_tty(&ttyfd, s->tty);
 574
 575                 /* Redirect stdin/stdout/stderr from the pseudo tty. */
 576                 if (dup2(ttyfd, 0) < 0)
 577                         error("dup2 stdin: %s", strerror(errno));
 578                 if (dup2(ttyfd, 1) < 0)
 579                         error("dup2 stdout: %s", strerror(errno));
 580                 if (dup2(ttyfd, 2) < 0)
 581                         error("dup2 stderr: %s", strerror(errno));
 582
 583                 /* Close the extra descriptor for the pseudo tty. */
 584                 close(ttyfd);
 585
 586                 /* record login, etc. similar to login(1) */
 587 #ifndef HAVE_OSF_SIA
 588                 if (!(options.use_login && command == NULL))
 589                         do_login(s, command);
 590 # ifdef LOGIN_NEEDS_UTMPX
 591                 else
 592                         do_pre_login(s);
 593 # endif
 594 #endif
 595
 596                 /* Do common processing for the child, such as execing the command. */
 597                 do_child(s, command);
 598                 /* NOTREACHED */
 599         }
 600 #ifdef HAVE_CYGWIN
 601         if (is_winnt)
 602                 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
 603 #endif
 604         if (pid < 0)
 605                 packet_disconnect("fork failed: %.100s", strerror(errno));
 606         s->pid = pid;
 607
 608         /* Parent.  Close the slave side of the pseudo tty. */
 609         close(ttyfd);
 610
 611         /*
 612          * Create another descriptor of the pty master side for use as the
 613          * standard input.  We could use the original descriptor, but this
 614          * simplifies code in server_loop.  The descriptor is bidirectional.
 615          */
 616         fdout = dup(ptyfd);
 617         if (fdout < 0)
 618                 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
 619
 620         /* we keep a reference to the pty master */
 621         ptymaster = dup(ptyfd);
 622         if (ptymaster < 0)
 623                 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
 624         s->ptymaster = ptymaster;
 625
 626         /* Enter interactive session. */
 627         packet_set_interactive(1);
 628         if (compat20) {
 629                 session_set_fds(s, ptyfd, fdout, -1);
 630         } else {
 631                 server_loop(pid, ptyfd, fdout, -1);
 632                 /* server_loop _has_ closed ptyfd and fdout. */
 633         }
 634 }
 635
 636 #ifdef LOGIN_NEEDS_UTMPX
 637 static void
 638 do_pre_login(Session *s)
 639 {
 640         socklen_t fromlen;
 641         struct sockaddr_storage from;
 642         pid_t pid = getpid();
 643
 644         /*
 645          * Get IP address of client. If the connection is not a socket, let
 646          * the address be 0.0.0.0.
 647          */
 648         memset(&from, 0, sizeof(from));
 649         if (packet_connection_is_on_socket()) {
 650                 fromlen = sizeof(from);
 651                 if (getpeername(packet_get_connection_in(),
 652                     (struct sockaddr *) & from, &fromlen) < 0) {
 653                         debug("getpeername: %.100s", strerror(errno));
 654                         fatal_cleanup();
 655                 }
 656         }
 657
 658         record_utmp_only(pid, s->tty, s->pw->pw_name,
 659             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 660             (struct sockaddr *)&from);
 661 }
 662 #endif
 663
 664 /*
 665  * This is called to fork and execute a command.  If another command is
 666  * to be forced, execute that instead.
 667  */
 668 void
 669 do_exec(Session *s, const char *command)
 670 {
 671         if (forced_command) {
 672                 original_command = command;
 673                 command = forced_command;
 674                 debug("Forced command '%.900s'", command);
 675         }
 676
 677         if (s->ttyfd != -1)
 678                 do_exec_pty(s, command);
 679         else
 680                 do_exec_no_pty(s, command);
 681
 682         original_command = NULL;
 683 }
 684
 685 /* administrative, login(1)-like work */
 686 void
 687 do_login(Session *s, const char *command)
 688 {
 689         char *time_string;
 690         char hostname[MAXHOSTNAMELEN];
 691         socklen_t fromlen;
 692         struct sockaddr_storage from;
 693         time_t last_login_time;
 694         struct passwd * pw = s->pw;
 695         pid_t pid = getpid();
 696
 697         /*
 698          * Get IP address of client. If the connection is not a socket, let
 699          * the address be 0.0.0.0.
 700          */
 701         memset(&from, 0, sizeof(from));
 702         if (packet_connection_is_on_socket()) {
 703                 fromlen = sizeof(from);
 704                 if (getpeername(packet_get_connection_in(),
 705                      (struct sockaddr *) & from, &fromlen) < 0) {
 706                         debug("getpeername: %.100s", strerror(errno));
 707                         fatal_cleanup();
 708                 }
 709         }
 710
 711         /* Get the time and hostname when the user last logged in. */
 712         if (options.print_lastlog) {
 713                 hostname[0] = '\0';
 714                 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
 715                     hostname, sizeof(hostname));
 716         }
 717
 718         /* Record that there was a login on that tty from the remote host. */
 719         record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
 720             get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
 721             (struct sockaddr *)&from);
 722
 723 #ifdef USE_PAM
 724         /*
 725          * If password change is needed, do it now.
 726          * This needs to occur before the ~/.hushlogin check.
 727          */
 728         if (is_pam_password_change_required()) {
 729                 print_pam_messages();
 730                 do_pam_chauthtok();
 731         }
 732 #endif
 733
 734         if (check_quietlogin(s, command))
 735                 return;
 736
 737 #ifdef USE_PAM
 738         if (!is_pam_password_change_required())
 739                 print_pam_messages();
 740 #endif /* USE_PAM */
 741 #ifdef WITH_AIXAUTHENTICATE
 742         if (aixloginmsg && *aixloginmsg)
 743                 printf("%s\n", aixloginmsg);
 744 #endif /* WITH_AIXAUTHENTICATE */
 745
 746         if (options.print_lastlog && last_login_time != 0) {
 747                 time_string = ctime(&last_login_time);
 748                 if (strchr(time_string, '\n'))
 749                         *strchr(time_string, '\n') = 0;
 750                 if (strcmp(hostname, "") == 0)
 751                         printf("Last login: %s\r\n", time_string);
 752                 else
 753                         printf("Last login: %s from %s\r\n", time_string, hostname);
 754         }
 755
 756         do_motd();
 757 }
 758
 759 /*
 760  * Display the message of the day.
 761  */
 762 void
 763 do_motd(void)
 764 {
 765         FILE *f;
 766         char buf[256];
 767
 768         if (options.print_motd) {
 769 #ifdef HAVE_LOGIN_CAP
 770                 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
 771                     "/etc/motd"), "r");
 772 #else
 773                 f = fopen("/etc/motd", "r");
 774 #endif
 775                 if (f) {
 776                         while (fgets(buf, sizeof(buf), f))
 777                                 fputs(buf, stdout);
 778                         fclose(f);
 779                 }
 780         }
 781 }
 782
 783
 784 /*
 785  * Check for quiet login, either .hushlogin or command given.
 786  */
 787 int
 788 check_quietlogin(Session *s, const char *command)
 789 {
 790         char buf[256];
 791         struct passwd *pw = s->pw;
 792         struct stat st;
 793
 794         /* Return 1 if .hushlogin exists or a command given. */
 795         if (command != NULL)
 796                 return 1;
 797         snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
 798 #ifdef HAVE_LOGIN_CAP
 799         if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
 800                 return 1;
 801 #else
 802         if (stat(buf, &st) >= 0)
 803                 return 1;
 804 #endif
 805         return 0;
 806 }
 807
 808 /*
 809  * Sets the value of the given variable in the environment.  If the variable
 810  * already exists, its value is overriden.
 811  */
 812 static void
 813 child_set_env(char ***envp, u_int *envsizep, const char *name,
 814         const char *value)
 815 {
 816         u_int i, namelen;
 817         char **env;
 818
 819         /*
 820          * Find the slot where the value should be stored.  If the variable
 821          * already exists, we reuse the slot; otherwise we append a new slot
 822          * at the end of the array, expanding if necessary.
 823          */
 824         env = *envp;
 825         namelen = strlen(name);
 826         for (i = 0; env[i]; i++)
 827                 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
 828                         break;
 829         if (env[i]) {
 830                 /* Reuse the slot. */
 831                 xfree(env[i]);
 832         } else {
 833                 /* New variable.  Expand if necessary. */
 834                 if (i >= (*envsizep) - 1) {
 835                         (*envsizep) += 50;
 836                         env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
 837                 }
 838                 /* Need to set the NULL pointer at end of array beyond the new slot. */
 839                 env[i + 1] = NULL;
 840         }
 841
 842         /* Allocate space and format the variable in the appropriate slot. */
 843         env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
 844         snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
 845 }
 846
 847 /*
 848  * Reads environment variables from the given file and adds/overrides them
 849  * into the environment.  If the file does not exist, this does nothing.
 850  * Otherwise, it must consist of empty lines, comments (line starts with '#')
 851  * and assignments of the form name=value.  No other forms are allowed.
 852  */
 853 static void
 854 read_environment_file(char ***env, u_int *envsize,
 855         const char *filename)
 856 {
 857         FILE *f;
 858         char buf[4096];
 859         char *cp, *value;
 860
 861         f = fopen(filename, "r");
 862         if (!f)
 863                 return;
 864
 865         while (fgets(buf, sizeof(buf), f)) {
 866                 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
 867                         ;
 868                 if (!*cp || *cp == '#' || *cp == '\n')
 869                         continue;
 870                 if (strchr(cp, '\n'))
 871                         *strchr(cp, '\n') = '\0';
 872                 value = strchr(cp, '=');
 873                 if (value == NULL) {
 874                         fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
 875                         continue;
 876                 }
 877                 /*
 878                  * Replace the equals sign by nul, and advance value to
 879                  * the value string.
 880                  */
 881                 *value = '\0';
 882                 value++;
 883                 child_set_env(env, envsize, cp, value);
 884         }
 885         fclose(f);
 886 }
 887
 888 void copy_environment(char **source, char ***env, u_int *envsize)
 889 {
 890         char *var_name, *var_val;
 891         int i;
 892
 893         if (source == NULL)
 894                 return;
 895
 896         for(i = 0; source[i] != NULL; i++) {
 897                 var_name = xstrdup(source[i]);
 898                 if ((var_val = strstr(var_name, "=")) == NULL) {
 899                         xfree(var_name);
 900                         continue;
 901                 }
 902                 *var_val++ = '\0';
 903
 904                 debug3("Copy environment: %s=%s", var_name, var_val);
 905                 child_set_env(env, envsize, var_name, var_val);
 906
 907                 xfree(var_name);
 908         }
 909 }
 910
 911 #if defined(HAVE_GETUSERATTR)
 912 /*
 913  * AIX-specific login initialisation
 914  */
 915 void set_limit(char *user, char *soft, char *hard, int resource, int mult)
 916 {
 917         struct rlimit rlim;
 918         int slim, hlim;
 919
 920         getrlimit(resource, &rlim);
 921
 922         slim = 0;
 923         if (getuserattr(user, soft, &slim, SEC_INT) != -1) {
 924                 if (slim < 0) {
 925                         rlim.rlim_cur = RLIM_INFINITY;
 926                 } else if (slim != 0) {
 927                         /* See the wackiness below */
 928                         if (rlim.rlim_cur == slim * mult)
 929                                 slim = 0;
 930                         else
 931                                 rlim.rlim_cur = slim * mult;
 932                 }
 933         }
 934
 935         hlim = 0;
 936         if (getuserattr(user, hard, &hlim, SEC_INT) != -1) {
 937                 if (hlim < 0) {
 938                         rlim.rlim_max = RLIM_INFINITY;
 939                 } else if (hlim != 0) {
 940                         rlim.rlim_max = hlim * mult;
 941                 }
 942         }
 943
 944         /*
 945          * XXX For cpu and fsize the soft limit is set to the hard limit
 946          * if the hard limit is left at its default value and the soft limit
 947          * is changed from its default value, either by requesting it
 948          * (slim == 0) or by setting it to the current default.  At least
 949          * that's how rlogind does it.  If you're confused you're not alone.
 950          * Bug or feature? AIX 4.3.1.2
 951          */
 952         if ((!strcmp(soft, "fsize") || !strcmp(soft, "cpu"))
 953             && hlim == 0 && slim != 0)
 954                 rlim.rlim_max = rlim.rlim_cur;
 955         /* A specified hard limit limits the soft limit */
 956         else if (hlim > 0 && rlim.rlim_cur > rlim.rlim_max)
 957                 rlim.rlim_cur = rlim.rlim_max;
 958         /* A soft limit can increase a hard limit */
 959         else if (rlim.rlim_cur > rlim.rlim_max)
 960                 rlim.rlim_max = rlim.rlim_cur;
 961
 962         if (setrlimit(resource, &rlim) != 0)
 963                 error("setrlimit(%.10s) failed: %.100s", soft, strerror(errno));
 964 }
 965
 966 void set_limits_from_userattr(char *user)
 967 {
 968         int mask;
 969         char buf[16];
 970
 971         set_limit(user, S_UFSIZE, S_UFSIZE_HARD, RLIMIT_FSIZE, 512);
 972         set_limit(user, S_UCPU, S_UCPU_HARD, RLIMIT_CPU, 1);
 973         set_limit(user, S_UDATA, S_UDATA_HARD, RLIMIT_DATA, 512);
 974         set_limit(user, S_USTACK, S_USTACK_HARD, RLIMIT_STACK, 512);
 975         set_limit(user, S_URSS, S_URSS_HARD, RLIMIT_RSS, 512);
 976         set_limit(user, S_UCORE, S_UCORE_HARD, RLIMIT_CORE, 512);
 977 #if defined(S_UNOFILE)
 978         set_limit(user, S_UNOFILE, S_UNOFILE_HARD, RLIMIT_NOFILE, 1);
 979 #endif
 980
 981         if (getuserattr(user, S_UMASK, &mask, SEC_INT) != -1) {
 982                 /* Convert decimal to octal */
 983                 (void) snprintf(buf, sizeof(buf), "%d", mask);
 984                 if (sscanf(buf, "%o", &mask) == 1)
 985                         umask(mask);
 986         }
 987 }
 988 #endif /* defined(HAVE_GETUSERATTR) */
 989
 990 /*
 991  * Performs common processing for the child, such as setting up the
 992  * environment, closing extra file descriptors, setting the user and group
 993  * ids, and executing the command or shell.
 994  */
 995 void
 996 do_child(Session *s, const char *command)
 997 {
 998         const char *shell, *hostname = NULL, *cp = NULL;
 999         struct passwd *pw = s->pw;
1000         char buf[256];
1001         char cmd[1024];
1002         FILE *f = NULL;
1003         u_int envsize, i;
1004         char **env;
1005         extern char **environ;
1006         struct stat st;
1007         char *argv[10];
1008         int do_xauth;
1009 #ifdef WITH_IRIX_PROJECT
1010         prid_t projid;
1011 #endif /* WITH_IRIX_PROJECT */
1012 #ifdef WITH_IRIX_JOBS
1013         jid_t jid = 0;
1014 #else
1015 #ifdef WITH_IRIX_ARRAY
1016         int jid = 0;
1017 #endif /* WITH_IRIX_ARRAY */
1018 #endif /* WITH_IRIX_JOBS */
1019
1020         do_xauth =
1021             s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1022
1023         /* remove hostkey from the child's memory */
1024         destroy_sensitive_data();
1025
1026         /* login(1) is only called if we execute the login shell */
1027         if (options.use_login && command != NULL)
1028                 options.use_login = 0;
1029
1030 #if !defined(HAVE_OSF_SIA)
1031         if (!options.use_login) {
1032 # ifdef HAVE_LOGIN_CAP
1033                 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1034                         f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1035                             _PATH_NOLOGIN), "r");
1036 # else /* HAVE_LOGIN_CAP */
1037                 if (pw->pw_uid)
1038                         f = fopen(_PATH_NOLOGIN, "r");
1039 # endif /* HAVE_LOGIN_CAP */
1040                 if (f) {
1041                         /* /etc/nologin exists.  Print its contents and exit. */
1042                         while (fgets(buf, sizeof(buf), f))
1043                                 fputs(buf, stderr);
1044                         fclose(f);
1045                         exit(254);
1046                 }
1047         }
1048 #endif /* HAVE_OSF_SIA */
1049
1050         /* Set login name, uid, gid, and groups. */
1051         /* Login(1) does this as well, and it needs uid 0 for the "-h"
1052            switch, so we let login(1) to this for us. */
1053         if (!options.use_login) {
1054 #ifdef HAVE_OSF_SIA
1055                 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1056                 if (!check_quietlogin(s, command))
1057                         do_motd();
1058 #else /* HAVE_OSF_SIA */
1059 #ifdef HAVE_CYGWIN
1060                 if (is_winnt) {
1061 #else
1062                 if (getuid() == 0 || geteuid() == 0) {
1063 #endif
1064 # ifdef HAVE_GETUSERATTR
1065                         set_limits_from_userattr(pw->pw_name);
1066 # endif /* HAVE_GETUSERATTR */
1067 # ifdef HAVE_LOGIN_CAP
1068                         if (setusercontext(lc, pw, pw->pw_uid,
1069                             (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1070                                 perror("unable to set user context");
1071                                 exit(1);
1072                         }
1073 # else /* HAVE_LOGIN_CAP */
1074 #if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1075                         /* Sets login uid for accounting */
1076                         if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1077                                 error("setluid: %s", strerror(errno));
1078 #endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1079
1080                         if (setlogin(pw->pw_name) < 0)
1081                                 error("setlogin failed: %s", strerror(errno));
1082                         if (setgid(pw->pw_gid) < 0) {
1083                                 perror("setgid");
1084                                 exit(1);
1085                         }
1086                         /* Initialize the group list. */
1087                         if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1088                                 perror("initgroups");
1089                                 exit(1);
1090                         }
1091                         endgrent();
1092 #  ifdef USE_PAM
1093                         /*
1094                          * PAM credentials may take the form of
1095                          * supplementary groups. These will have been
1096                          * wiped by the above initgroups() call.
1097                          * Reestablish them here.
1098                          */
1099                         do_pam_setcred(0);
1100 #  endif /* USE_PAM */
1101 #  ifdef WITH_IRIX_JOBS
1102                         jid = jlimit_startjob(pw->pw_name, pw->pw_uid, "interactive");
1103                         if (jid == -1) {
1104                                 fatal("Failed to create job container: %.100s",
1105                                       strerror(errno));
1106                         }
1107 #  endif /* WITH_IRIX_JOBS */
1108 #  ifdef WITH_IRIX_ARRAY
1109                         /* initialize array session */
1110                         if (jid == 0) {
1111                                 if (newarraysess() != 0)
1112                                         fatal("Failed to set up new array session: %.100s",
1113                                               strerror(errno));
1114                         }
1115 #  endif /* WITH_IRIX_ARRAY */
1116 #  ifdef WITH_IRIX_PROJECT
1117                         /* initialize irix project info */
1118                         if ((projid = getdfltprojuser(pw->pw_name)) == -1) {
1119                           debug("Failed to get project id, using projid 0");
1120                           projid = 0;
1121                         }
1122                         if (setprid(projid))
1123                           fatal("Failed to initialize project %d for %s: %.100s",
1124                                 (int)projid, pw->pw_name, strerror(errno));
1125 #  endif /* WITH_IRIX_PROJECT */
1126 #ifdef WITH_IRIX_AUDIT
1127                         if (sysconf(_SC_AUDIT)) {
1128                                 debug("Setting sat id to %d", (int) pw->pw_uid);
1129                                 if (satsetid(pw->pw_uid))
1130                                         debug("error setting satid: %.100s", strerror(errno));
1131                         }
1132 #endif /* WITH_IRIX_AUDIT */
1133
1134 #ifdef _AIX
1135                         /*
1136                          * AIX has a "usrinfo" area where logname and
1137                          * other stuff is stored - a few applications
1138                          * actually use this and die if it's not set
1139                          */
1140                         if (s->ttyfd == -1)
1141                                 s->tty[0] = '\0';
1142                         cp = xmalloc(22 + strlen(s->tty) +
1143                             2 * strlen(pw->pw_name));
1144                         i = sprintf(cp, "LOGNAME=%s%cNAME=%s%cTTY=%s%c%c",
1145                             pw->pw_name, 0, pw->pw_name, 0, s->tty, 0, 0);
1146                         if (usrinfo(SETUINFO, cp, i) == -1)
1147                                 fatal("Couldn't set usrinfo: %s",
1148                                     strerror(errno));
1149                         debug3("AIX/UsrInfo: set len %d", i);
1150                         xfree(cp);
1151 #endif
1152
1153                         /* Permanently switch to the desired uid. */
1154                         permanently_set_uid(pw);
1155 # endif /* HAVE_LOGIN_CAP */
1156                 }
1157 #endif /* HAVE_OSF_SIA */
1158
1159 #ifdef HAVE_CYGWIN
1160                 if (is_winnt)
1161 #endif
1162                 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1163                         fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1164         }
1165         /*
1166          * Get the shell from the password data.  An empty shell field is
1167          * legal, and means /bin/sh.
1168          */
1169         shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1170 #ifdef HAVE_LOGIN_CAP
1171         shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1172 #endif
1173
1174         /* Initialize the environment. */
1175         envsize = 100;
1176         env = xmalloc(envsize * sizeof(char *));
1177         env[0] = NULL;
1178
1179 #ifdef HAVE_CYGWIN
1180         /*
1181          * The Windows environment contains some setting which are
1182          * important for a running system. They must not be dropped.
1183          */
1184         copy_environment(environ, &env, &envsize);
1185 #endif
1186
1187         if (!options.use_login) {
1188                 /* Set basic environment. */
1189                 child_set_env(&env, &envsize, "USER", pw->pw_name);
1190                 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1191                 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1192 #ifdef HAVE_LOGIN_CAP
1193                 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
1194                 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1195 #else /* HAVE_LOGIN_CAP */
1196 # ifndef HAVE_CYGWIN
1197                 /*
1198                  * There's no standard path on Windows. The path contains
1199                  * important components pointing to the system directories,
1200                  * needed for loading shared libraries. So the path better
1201                  * remains intact here.
1202                  */
1203                 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1204 # endif /* HAVE_CYGWIN */
1205 #endif /* HAVE_LOGIN_CAP */
1206
1207                 snprintf(buf, sizeof buf, "%.200s/%.50s",
1208                          _PATH_MAILDIR, pw->pw_name);
1209                 child_set_env(&env, &envsize, "MAIL", buf);
1210
1211                 /* Normal systems set SHELL by default. */
1212                 child_set_env(&env, &envsize, "SHELL", shell);
1213         }
1214         if (getenv("TZ"))
1215                 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1216
1217         /* Set custom environment options from RSA authentication. */
1218         if (!options.use_login) {
1219                 while (custom_environment) {
1220                         struct envstring *ce = custom_environment;
1221                         char *s = ce->s;
1222                         int i;
1223                         for (i = 0; s[i] != '=' && s[i]; i++)
1224                                 ;
1225                         if (s[i] == '=') {
1226                                 s[i] = 0;
1227                                 child_set_env(&env, &envsize, s, s + i + 1);
1228                         }
1229                         custom_environment = ce->next;
1230                         xfree(ce->s);
1231                         xfree(ce);
1232                 }
1233         }
1234
1235         snprintf(buf, sizeof buf, "%.50s %d %d",
1236                  get_remote_ipaddr(), get_remote_port(), get_local_port());
1237         child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1238
1239         if (s->ttyfd != -1)
1240                 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1241         if (s->term)
1242                 child_set_env(&env, &envsize, "TERM", s->term);
1243         if (s->display)
1244                 child_set_env(&env, &envsize, "DISPLAY", s->display);
1245         if (original_command)
1246                 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1247                     original_command);
1248
1249 #ifdef _AIX
1250         if ((cp = getenv("AUTHSTATE")) != NULL)
1251                 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1252         if ((cp = getenv("KRB5CCNAME")) != NULL)
1253                 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1254         read_environment_file(&env, &envsize, "/etc/environment");
1255 #endif
1256 #ifdef KRB4
1257         if (s->authctxt->krb4_ticket_file)
1258                 child_set_env(&env, &envsize, "KRBTKFILE",
1259                     s->authctxt->krb4_ticket_file);
1260 #endif
1261 #ifdef KRB5
1262         if (s->authctxt->krb5_ticket_file)
1263                 child_set_env(&env, &envsize, "KRB5CCNAME",
1264                     s->authctxt->krb5_ticket_file);
1265 #endif
1266 #ifdef USE_PAM
1267         /* Pull in any environment variables that may have been set by PAM. */
1268         copy_environment(fetch_pam_environment(), &env, &envsize);
1269 #endif /* USE_PAM */
1270
1271         if (auth_get_socket_name() != NULL)
1272                 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1273                     auth_get_socket_name());
1274
1275         /* read $HOME/.ssh/environment. */
1276         if (!options.use_login) {
1277                 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1278                     pw->pw_dir);
1279                 read_environment_file(&env, &envsize, buf);
1280         }
1281         if (debug_flag) {
1282                 /* dump the environment */
1283                 fprintf(stderr, "Environment:\n");
1284                 for (i = 0; env[i]; i++)
1285                         fprintf(stderr, "  %.200s\n", env[i]);
1286         }
1287         /* we have to stash the hostname before we close our socket. */
1288         if (options.use_login)
1289                 hostname = get_remote_name_or_ip(utmp_len,
1290                     options.reverse_mapping_check);
1291         /*
1292          * Close the connection descriptors; note that this is the child, and
1293          * the server will still have the socket open, and it is important
1294          * that we do not shutdown it.  Note that the descriptors cannot be
1295          * closed before building the environment, as we call
1296          * get_remote_ipaddr there.
1297          */
1298         if (packet_get_connection_in() == packet_get_connection_out())
1299                 close(packet_get_connection_in());
1300         else {
1301                 close(packet_get_connection_in());
1302                 close(packet_get_connection_out());
1303         }
1304         /*
1305          * Close all descriptors related to channels.  They will still remain
1306          * open in the parent.
1307          */
1308         /* XXX better use close-on-exec? -markus */
1309         channel_close_all();
1310
1311         /*
1312          * Close any extra file descriptors.  Note that there may still be
1313          * descriptors left by system functions.  They will be closed later.
1314          */
1315         endpwent();
1316
1317         /*
1318          * Close any extra open file descriptors so that we don\'t have them
1319          * hanging around in clients.  Note that we want to do this after
1320          * initgroups, because at least on Solaris 2.3 it leaves file
1321          * descriptors open.
1322          */
1323         for (i = 3; i < 64; i++)
1324                 close(i);
1325
1326         /*
1327          * Must take new environment into use so that .ssh/rc, /etc/sshrc and
1328          * xauth are run in the proper environment.
1329          */
1330         environ = env;
1331
1332 #ifdef AFS
1333         /* Try to get AFS tokens for the local cell. */
1334         if (k_hasafs()) {
1335                 char cell[64];
1336
1337                 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1338                         krb_afslog(cell, 0);
1339
1340                 krb_afslog(0, 0);
1341         }
1342 #endif /* AFS */
1343
1344         /* Change current directory to the user\'s home directory. */
1345         if (chdir(pw->pw_dir) < 0) {
1346                 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1347                     pw->pw_dir, strerror(errno));
1348 #ifdef HAVE_LOGIN_CAP
1349                 if (login_getcapbool(lc, "requirehome", 0))
1350                         exit(1);
1351 #endif
1352         }
1353
1354         /*
1355          * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
1356          * in this order).
1357          */
1358         if (!options.use_login) {
1359                 /* ignore _PATH_SSH_USER_RC for subsystems */
1360                 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1361                         snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1362                             shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1363                         if (debug_flag)
1364                                 fprintf(stderr, "Running %s\n", cmd);
1365                         f = popen(cmd, "w");
1366                         if (f) {
1367                                 if (do_xauth)
1368                                         fprintf(f, "%s %s\n", s->auth_proto,
1369                                             s->auth_data);
1370                                 pclose(f);
1371                         } else
1372                                 fprintf(stderr, "Could not run %s\n",
1373                                     _PATH_SSH_USER_RC);
1374                 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1375                         if (debug_flag)
1376                                 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1377                                     _PATH_SSH_SYSTEM_RC);
1378                         f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1379                         if (f) {
1380                                 if (do_xauth)
1381                                         fprintf(f, "%s %s\n", s->auth_proto,
1382                                             s->auth_data);
1383                                 pclose(f);
1384                         } else
1385                                 fprintf(stderr, "Could not run %s\n",
1386                                     _PATH_SSH_SYSTEM_RC);
1387                 } else if (do_xauth && options.xauth_location != NULL) {
1388                         /* Add authority data to .Xauthority if appropriate. */
1389                         if (debug_flag) {
1390                                 fprintf(stderr,
1391                                     "Running %.100s add "
1392                                     "%.100s %.100s %.100s\n",
1393                                     options.xauth_location, s->auth_display[0],
1394                                     s->auth_proto, s->auth_data);
1395                                 if (s->auth_display[1])
1396                                         fprintf(stderr,
1397                                             "add %.100s %.100s %.100s\n",
1398                                             s->auth_display[1],
1399                                             s->auth_proto, s->auth_data);
1400                         }
1401                         snprintf(cmd, sizeof cmd, "%s -q -",
1402                             options.xauth_location);
1403                         f = popen(cmd, "w");
1404                         if (f) {
1405                                 fprintf(f, "add %s %s %s\n",
1406                                     s->auth_display[0], s->auth_proto,
1407                                     s->auth_data);
1408                                 if (s->auth_display[1])
1409                                         fprintf(f, "add %s %s %s\n",
1410                                             s->auth_display[1], s->auth_proto,
1411                                             s->auth_data);
1412                                 pclose(f);
1413                         } else {
1414                                 fprintf(stderr, "Could not run %s\n",
1415                                     cmd);
1416                         }
1417                 }
1418                 /* Get the last component of the shell name. */
1419                 cp = strrchr(shell, '/');
1420                 if (cp)
1421                         cp++;
1422                 else
1423                         cp = shell;
1424         }
1425
1426         /* restore SIGPIPE for child */
1427         signal(SIGPIPE,  SIG_DFL);
1428
1429         /*
1430          * If we have no command, execute the shell.  In this case, the shell
1431          * name to be passed in argv[0] is preceded by '-' to indicate that
1432          * this is a login shell.
1433          */
1434         if (!command) {
1435                 if (!options.use_login) {
1436                         char buf[256];
1437
1438                         /* Start the shell.  Set initial character to '-'. */
1439                         buf[0] = '-';
1440                         strlcpy(buf + 1, cp, sizeof(buf) - 1);
1441
1442                         /* Execute the shell. */
1443                         argv[0] = buf;
1444                         argv[1] = NULL;
1445                         execve(shell, argv, env);
1446
1447                         /* Executing the shell failed. */
1448                         perror(shell);
1449                         exit(1);
1450
1451                 } else {
1452                         /* Launch login(1). */
1453
1454                         execl(LOGIN_PROGRAM, "login", "-h", hostname,
1455 #ifdef LOGIN_NEEDS_TERM
1456                             s->term? s->term : "unknown",
1457 #endif
1458                             "-p", "-f", "--", pw->pw_name, (char *)NULL);
1459
1460                         /* Login couldn't be executed, die. */
1461
1462                         perror("login");
1463                         exit(1);
1464                 }
1465         }
1466         /*
1467          * Execute the command using the user's shell.  This uses the -c
1468          * option to execute the command.
1469          */
1470         argv[0] = (char *) cp;
1471         argv[1] = "-c";
1472         argv[2] = (char *) command;
1473         argv[3] = NULL;
1474         execve(shell, argv, env);
1475         perror(shell);
1476         exit(1);
1477 }
1478
1479 Session *
1480 session_new(void)
1481 {
1482         int i;
1483         static int did_init = 0;
1484         if (!did_init) {
1485                 debug("session_new: init");
1486                 for (i = 0; i < MAX_SESSIONS; i++) {
1487                         sessions[i].used = 0;
1488                 }
1489                 did_init = 1;
1490         }
1491         for (i = 0; i < MAX_SESSIONS; i++) {
1492                 Session *s = &sessions[i];
1493                 if (! s->used) {
1494                         memset(s, 0, sizeof(*s));
1495                         s->chanid = -1;
1496                         s->ptyfd = -1;
1497                         s->ttyfd = -1;
1498                         s->used = 1;
1499                         s->self = i;
1500                         debug("session_new: session %d", i);
1501                         return s;
1502                 }
1503         }
1504         return NULL;
1505 }
1506
1507 static void
1508 session_dump(void)
1509 {
1510         int i;
1511         for (i = 0; i < MAX_SESSIONS; i++) {
1512                 Session *s = &sessions[i];
1513                 debug("dump: used %d session %d %p channel %d pid %d",
1514                     s->used,
1515                     s->self,
1516                     s,
1517                     s->chanid,
1518                     s->pid);
1519         }
1520 }
1521
1522 int
1523 session_open(Authctxt *authctxt, int chanid)
1524 {
1525         Session *s = session_new();
1526         debug("session_open: channel %d", chanid);
1527         if (s == NULL) {
1528                 error("no more sessions");
1529                 return 0;
1530         }
1531         s->authctxt = authctxt;
1532         s->pw = authctxt->pw;
1533         if (s->pw == NULL)
1534                 fatal("no user for session %d", s->self);
1535         debug("session_open: session %d: link with channel %d", s->self, chanid);
1536         s->chanid = chanid;
1537         return 1;
1538 }
1539
1540 static Session *
1541 session_by_channel(int id)
1542 {
1543         int i;
1544         for (i = 0; i < MAX_SESSIONS; i++) {
1545                 Session *s = &sessions[i];
1546                 if (s->used && s->chanid == id) {
1547                         debug("session_by_channel: session %d channel %d", i, id);
1548                         return s;
1549                 }
1550         }
1551         debug("session_by_channel: unknown channel %d", id);
1552         session_dump();
1553         return NULL;
1554 }
1555
1556 static Session *
1557 session_by_pid(pid_t pid)
1558 {
1559         int i;
1560         debug("session_by_pid: pid %d", pid);
1561         for (i = 0; i < MAX_SESSIONS; i++) {
1562                 Session *s = &sessions[i];
1563                 if (s->used && s->pid == pid)
1564                         return s;
1565         }
1566         error("session_by_pid: unknown pid %d", pid);
1567         session_dump();
1568         return NULL;
1569 }
1570
1571 static int
1572 session_window_change_req(Session *s)
1573 {
1574         s->col = packet_get_int();
1575         s->row = packet_get_int();
1576         s->xpixel = packet_get_int();
1577         s->ypixel = packet_get_int();
1578         packet_check_eom();
1579         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1580         return 1;
1581 }
1582
1583 static int
1584 session_pty_req(Session *s)
1585 {
1586         u_int len;
1587         int n_bytes;
1588
1589         if (no_pty_flag) {
1590                 debug("Allocating a pty not permitted for this authentication.");
1591                 return 0;
1592         }
1593         if (s->ttyfd != -1) {
1594                 packet_disconnect("Protocol error: you already have a pty.");
1595                 return 0;
1596         }
1597
1598         s->term = packet_get_string(&len);
1599
1600         if (compat20) {
1601                 s->col = packet_get_int();
1602                 s->row = packet_get_int();
1603         } else {
1604                 s->row = packet_get_int();
1605                 s->col = packet_get_int();
1606         }
1607         s->xpixel = packet_get_int();
1608         s->ypixel = packet_get_int();
1609
1610         if (strcmp(s->term, "") == 0) {
1611                 xfree(s->term);
1612                 s->term = NULL;
1613         }
1614
1615         /* Allocate a pty and open it. */
1616         debug("Allocating pty.");
1617         if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1618                 if (s->term)
1619                         xfree(s->term);
1620                 s->term = NULL;
1621                 s->ptyfd = -1;
1622                 s->ttyfd = -1;
1623                 error("session_pty_req: session %d alloc failed", s->self);
1624                 return 0;
1625         }
1626         debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1627
1628         /* for SSH1 the tty modes length is not given */
1629         if (!compat20)
1630                 n_bytes = packet_remaining();
1631         tty_parse_modes(s->ttyfd, &n_bytes);
1632
1633         /*
1634          * Add a cleanup function to clear the utmp entry and record logout
1635          * time in case we call fatal() (e.g., the connection gets closed).
1636          */
1637         fatal_add_cleanup(session_pty_cleanup, (void *)s);
1638         pty_setowner(s->pw, s->tty);
1639
1640         /* Set window size from the packet. */
1641         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1642
1643         packet_check_eom();
1644         session_proctitle(s);
1645         return 1;
1646 }
1647
1648 static int
1649 session_subsystem_req(Session *s)
1650 {
1651         struct stat st;
1652         u_int len;
1653         int success = 0;
1654         char *cmd, *subsys = packet_get_string(&len);
1655         int i;
1656
1657         packet_check_eom();
1658         log("subsystem request for %s", subsys);
1659
1660         for (i = 0; i < options.num_subsystems; i++) {
1661                 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1662                         cmd = options.subsystem_command[i];
1663                         if (stat(cmd, &st) < 0) {
1664                                 error("subsystem: cannot stat %s: %s", cmd,
1665                                     strerror(errno));
1666                                 break;
1667                         }
1668                         debug("subsystem: exec() %s", cmd);
1669                         s->is_subsystem = 1;
1670                         do_exec(s, cmd);
1671                         success = 1;
1672                 }
1673         }
1674
1675         if (!success)
1676                 log("subsystem request for %s failed, subsystem not found",
1677                     subsys);
1678
1679         xfree(subsys);
1680         return success;
1681 }
1682
1683 static int
1684 session_x11_req(Session *s)
1685 {
1686         int success;
1687
1688         s->single_connection = packet_get_char();
1689         s->auth_proto = packet_get_string(NULL);
1690         s->auth_data = packet_get_string(NULL);
1691         s->screen = packet_get_int();
1692         packet_check_eom();
1693
1694         success = session_setup_x11fwd(s);
1695         if (!success) {
1696                 xfree(s->auth_proto);
1697                 xfree(s->auth_data);
1698                 s->auth_proto = NULL;
1699                 s->auth_data = NULL;
1700         }
1701         return success;
1702 }
1703
1704 static int
1705 session_shell_req(Session *s)
1706 {
1707         packet_check_eom();
1708         do_exec(s, NULL);
1709         return 1;
1710 }
1711
1712 static int
1713 session_exec_req(Session *s)
1714 {
1715         u_int len;
1716         char *command = packet_get_string(&len);
1717         packet_check_eom();
1718         do_exec(s, command);
1719         xfree(command);
1720         return 1;
1721 }
1722
1723 static int
1724 session_auth_agent_req(Session *s)
1725 {
1726         static int called = 0;
1727         packet_check_eom();
1728         if (no_agent_forwarding_flag) {
1729                 debug("session_auth_agent_req: no_agent_forwarding_flag");
1730                 return 0;
1731         }
1732         if (called) {
1733                 return 0;
1734         } else {
1735                 called = 1;
1736                 return auth_input_request_forwarding(s->pw);
1737         }
1738 }
1739
1740 void
1741 session_input_channel_req(int id, void *arg)
1742 {
1743         u_int len;
1744         int reply;
1745         int success = 0;
1746         char *rtype;
1747         Session *s;
1748         Channel *c;
1749
1750         rtype = packet_get_string(&len);
1751         reply = packet_get_char();
1752
1753         s = session_by_channel(id);
1754         if (s == NULL)
1755                 fatal("session_input_channel_req: channel %d: no session", id);
1756         c = channel_lookup(id);
1757         if (c == NULL)
1758                 fatal("session_input_channel_req: channel %d: bad channel", id);
1759
1760         debug("session_input_channel_req: session %d channel %d request %s reply %d",
1761             s->self, id, rtype, reply);
1762
1763         /*
1764          * a session is in LARVAL state until a shell, a command
1765          * or a subsystem is executed
1766          */
1767         if (c->type == SSH_CHANNEL_LARVAL) {
1768                 if (strcmp(rtype, "shell") == 0) {
1769                         success = session_shell_req(s);
1770                 } else if (strcmp(rtype, "exec") == 0) {
1771                         success = session_exec_req(s);
1772                 } else if (strcmp(rtype, "pty-req") == 0) {
1773                         success =  session_pty_req(s);
1774                 } else if (strcmp(rtype, "x11-req") == 0) {
1775                         success = session_x11_req(s);
1776                 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1777                         success = session_auth_agent_req(s);
1778                 } else if (strcmp(rtype, "subsystem") == 0) {
1779                         success = session_subsystem_req(s);
1780                 }
1781         }
1782         if (strcmp(rtype, "window-change") == 0) {
1783                 success = session_window_change_req(s);
1784         }
1785
1786         if (reply) {
1787                 packet_start(success ?
1788                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1789                 packet_put_int(c->remote_id);
1790                 packet_send();
1791         }
1792         xfree(rtype);
1793 }
1794
1795 void
1796 session_set_fds(Session *s, int fdin, int fdout, int fderr)
1797 {
1798         if (!compat20)
1799                 fatal("session_set_fds: called for proto != 2.0");
1800         /*
1801          * now that have a child and a pipe to the child,
1802          * we can activate our channel and register the fd's
1803          */
1804         if (s->chanid == -1)
1805                 fatal("no channel for session %d", s->self);
1806         channel_set_fds(s->chanid,
1807             fdout, fdin, fderr,
1808             fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1809             1);
1810 }
1811
1812 /*
1813  * Function to perform pty cleanup. Also called if we get aborted abnormally
1814  * (e.g., due to a dropped connection).
1815  */
1816 static void
1817 session_pty_cleanup(void *session)
1818 {
1819         Session *s = session;
1820
1821         if (s == NULL) {
1822                 error("session_pty_cleanup: no session");
1823                 return;
1824         }
1825         if (s->ttyfd == -1)
1826                 return;
1827
1828         debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1829
1830         /* Record that the user has logged out. */
1831         if (s->pid != 0)
1832                 record_logout(s->pid, s->tty);
1833
1834         /* Release the pseudo-tty. */
1835         pty_release(s->tty);
1836
1837         /*
1838          * Close the server side of the socket pairs.  We must do this after
1839          * the pty cleanup, so that another process doesn't get this pty
1840          * while we're still cleaning up.
1841          */
1842         if (close(s->ptymaster) < 0)
1843                 error("close(s->ptymaster): %s", strerror(errno));
1844
1845         /* unlink pty from session */
1846         s->ttyfd = -1;
1847 }
1848
1849 static void
1850 session_exit_message(Session *s, int status)
1851 {
1852         Channel *c;
1853         if (s == NULL)
1854                 fatal("session_close: no session");
1855         c = channel_lookup(s->chanid);
1856         if (c == NULL)
1857                 fatal("session_exit_message: session %d: no channel %d",
1858                     s->self, s->chanid);
1859         debug("session_exit_message: session %d channel %d pid %d",
1860             s->self, s->chanid, s->pid);
1861
1862         if (WIFEXITED(status)) {
1863                 channel_request_start(s->chanid,
1864                     "exit-status", 0);
1865                 packet_put_int(WEXITSTATUS(status));
1866                 packet_send();
1867         } else if (WIFSIGNALED(status)) {
1868                 channel_request_start(s->chanid,
1869                     "exit-signal", 0);
1870                 packet_put_int(WTERMSIG(status));
1871 #ifdef WCOREDUMP
1872                 packet_put_char(WCOREDUMP(status));
1873 #else /* WCOREDUMP */
1874                 packet_put_char(0);
1875 #endif /* WCOREDUMP */
1876                 packet_put_cstring("");
1877                 packet_put_cstring("");
1878                 packet_send();
1879         } else {
1880                 /* Some weird exit cause.  Just exit. */
1881                 packet_disconnect("wait returned status %04x.", status);
1882         }
1883
1884         /* disconnect channel */
1885         debug("session_exit_message: release channel %d", s->chanid);
1886         channel_cancel_cleanup(s->chanid);
1887         /*
1888          * emulate a write failure with 'chan_write_failed', nobody will be
1889          * interested in data we write.
1890          * Note that we must not call 'chan_read_failed', since there could
1891          * be some more data waiting in the pipe.
1892          */
1893         if (c->ostate != CHAN_OUTPUT_CLOSED)
1894                 chan_write_failed(c);
1895         s->chanid = -1;
1896 }
1897
1898 static void
1899 session_close(Session *s)
1900 {
1901         debug("session_close: session %d pid %d", s->self, s->pid);
1902         if (s->ttyfd != -1) {
1903                 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1904                 session_pty_cleanup(s);
1905         }
1906         if (s->term)
1907                 xfree(s->term);
1908         if (s->display)
1909                 xfree(s->display);
1910         if (s->auth_display[0])
1911                 xfree(s->auth_display[0]);
1912         if (s->auth_display[1])
1913                 xfree(s->auth_display[1]);
1914         if (s->auth_data)
1915                 xfree(s->auth_data);
1916         if (s->auth_proto)
1917                 xfree(s->auth_proto);
1918         s->used = 0;
1919         session_proctitle(s);
1920 }
1921
1922 void
1923 session_close_by_pid(pid_t pid, int status)
1924 {
1925         Session *s = session_by_pid(pid);
1926         if (s == NULL) {
1927                 debug("session_close_by_pid: no session for pid %d", pid);
1928                 return;
1929         }
1930         if (s->chanid != -1)
1931                 session_exit_message(s, status);
1932         session_close(s);
1933 }
1934
1935 /*
1936  * this is called when a channel dies before
1937  * the session 'child' itself dies
1938  */
1939 void
1940 session_close_by_channel(int id, void *arg)
1941 {
1942         Session *s = session_by_channel(id);
1943         if (s == NULL) {
1944                 debug("session_close_by_channel: no session for id %d", id);
1945                 return;
1946         }
1947         debug("session_close_by_channel: channel %d child %d", id, s->pid);
1948         if (s->pid != 0) {
1949                 debug("session_close_by_channel: channel %d: has child", id);
1950                 /*
1951                  * delay detach of session, but release pty, since
1952                  * the fd's to the child are already closed
1953                  */
1954                 if (s->ttyfd != -1) {
1955                         fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1956                         session_pty_cleanup(s);
1957                 }
1958                 return;
1959         }
1960         /* detach by removing callback */
1961         channel_cancel_cleanup(s->chanid);
1962         s->chanid = -1;
1963         session_close(s);
1964 }
1965
1966 void
1967 session_destroy_all(void)
1968 {
1969         int i;
1970         for (i = 0; i < MAX_SESSIONS; i++) {
1971                 Session *s = &sessions[i];
1972                 if (s->used)
1973                         session_close(s);
1974         }
1975 }
1976
1977 static char *
1978 session_tty_list(void)
1979 {
1980         static char buf[1024];
1981         int i;
1982         buf[0] = '\0';
1983         for (i = 0; i < MAX_SESSIONS; i++) {
1984                 Session *s = &sessions[i];
1985                 if (s->used && s->ttyfd != -1) {
1986                         if (buf[0] != '\0')
1987                                 strlcat(buf, ",", sizeof buf);
1988                         strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1989                 }
1990         }
1991         if (buf[0] == '\0')
1992                 strlcpy(buf, "notty", sizeof buf);
1993         return buf;
1994 }
1995
1996 void
1997 session_proctitle(Session *s)
1998 {
1999         if (s->pw == NULL)
2000                 error("no user for session %d", s->self);
2001         else
2002                 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2003 }
2004
2005 int
2006 session_setup_x11fwd(Session *s)
2007 {
2008         struct stat st;
2009         char display[512], auth_display[512];
2010         char hostname[MAXHOSTNAMELEN];
2011
2012         if (no_x11_forwarding_flag) {
2013                 packet_send_debug("X11 forwarding disabled in user configuration file.");
2014                 return 0;
2015         }
2016         if (!options.x11_forwarding) {
2017                 debug("X11 forwarding disabled in server configuration file.");
2018                 return 0;
2019         }
2020         if (!options.xauth_location ||
2021             (stat(options.xauth_location, &st) == -1)) {
2022                 packet_send_debug("No xauth program; cannot forward with spoofing.");
2023                 return 0;
2024         }
2025         if (options.use_login) {
2026                 packet_send_debug("X11 forwarding disabled; "
2027                     "not compatible with UseLogin=yes.");
2028                 return 0;
2029         }
2030         if (s->display != NULL) {
2031                 debug("X11 display already set.");
2032                 return 0;
2033         }
2034         s->display_number = x11_create_display_inet(options.x11_display_offset,
2035             options.gateway_ports, s->single_connection);
2036         if (s->display_number == -1) {
2037                 debug("x11_create_display_inet failed.");
2038                 return 0;
2039         }
2040
2041         /* Set up a suitable value for the DISPLAY variable. */
2042         if (gethostname(hostname, sizeof(hostname)) < 0)
2043                 fatal("gethostname: %.100s", strerror(errno));
2044         /*
2045          * auth_display must be used as the displayname when the
2046          * authorization entry is added with xauth(1).  This will be
2047          * different than the DISPLAY string for localhost displays.
2048          */
2049         s->auth_display[1] = NULL;
2050         if (!options.gateway_ports) {
2051                 struct utsname uts;
2052
2053                 snprintf(display, sizeof display, "localhost:%d.%d",
2054                     s->display_number, s->screen);
2055                 snprintf(auth_display, sizeof auth_display, "%.400s/unix:%d.%d",
2056                     hostname, s->display_number, s->screen);
2057                 s->display = xstrdup(display);
2058                 s->auth_display[0] = xstrdup(auth_display);
2059                 /*
2060                  * Xlib may use gethostbyname() or uname() hostname to
2061                  * look up authorization data for FamilyLocal; see:
2062                  * xc/lib/xtrans/Xtrans.c:TRANS(GetHostname)
2063                  * We just add authorization entries with both
2064                  * hostname and nodename if they are different.
2065                  */
2066                 if (uname(&uts) == -1)
2067                         fatal("uname: %.100s", strerror(errno));
2068                 if (strcmp(hostname, uts.nodename) != 0) {
2069                         snprintf(auth_display, sizeof auth_display,
2070                             "%.400s/unix:%d.%d", uts.nodename,
2071                             s->display_number, s->screen);
2072                         s->auth_display[1] = xstrdup(auth_display);
2073                 }
2074         } else {
2075 #ifdef IPADDR_IN_DISPLAY
2076                 struct hostent *he;
2077                 struct in_addr my_addr;
2078
2079                 he = gethostbyname(hostname);
2080                 if (he == NULL) {
2081                         error("Can't get IP address for X11 DISPLAY.");
2082                         packet_send_debug("Can't get IP address for X11 DISPLAY.");
2083                         return 0;
2084                 }
2085                 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2086                 snprintf(display, sizeof display, "%.50s:%d.%d", inet_ntoa(my_addr),
2087                     s->display_number, s->screen);
2088 #else
2089                 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2090                     s->display_number, s->screen);
2091 #endif
2092                 s->display = xstrdup(display);
2093                 s->auth_display[0] = xstrdup(display);
2094         }
2095
2096         return 1;
2097 }
2098
2099 static void
2100 do_authenticated2(Authctxt *authctxt)
2101 {
2102         server_loop2(authctxt);
2103 }