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Annotation of src/usr.bin/ssh/session.c, Revision 1.230.2.1

1.230.2.1! brad        1: /* $OpenBSD: session.c,v 1.230 2008/02/22 05:58:56 djm Exp $ */
1.1       markus      2: /*
                      3:  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                      4:  *                    All rights reserved
1.37      deraadt     5:  *
                      6:  * As far as I am concerned, the code I have written for this software
                      7:  * can be used freely for any purpose.  Any derived versions of this
                      8:  * software must be clearly marked as such, and if the derived work is
                      9:  * incompatible with the protocol description in the RFC file, it must be
                     10:  * called by a name other than "ssh" or "Secure Shell".
                     11:  *
1.2       markus     12:  * SSH2 support by Markus Friedl.
1.95      markus     13:  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
1.37      deraadt    14:  *
                     15:  * Redistribution and use in source and binary forms, with or without
                     16:  * modification, are permitted provided that the following conditions
                     17:  * are met:
                     18:  * 1. Redistributions of source code must retain the above copyright
                     19:  *    notice, this list of conditions and the following disclaimer.
                     20:  * 2. Redistributions in binary form must reproduce the above copyright
                     21:  *    notice, this list of conditions and the following disclaimer in the
                     22:  *    documentation and/or other materials provided with the distribution.
                     23:  *
                     24:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
                     25:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
                     26:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     27:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
                     28:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
                     29:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
                     30:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
                     31:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
                     32:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
                     33:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.2       markus     34:  */
1.1       markus     35:
1.193     stevesk    36: #include <sys/types.h>
                     37: #include <sys/wait.h>
1.194     stevesk    38: #include <sys/un.h>
1.196     stevesk    39: #include <sys/stat.h>
1.207     stevesk    40: #include <sys/socket.h>
1.213     stevesk    41: #include <sys/param.h>
1.192     stevesk    42:
1.209     stevesk    43: #include <errno.h>
1.204     stevesk    44: #include <grp.h>
1.223     djm        45: #include <login_cap.h>
1.192     stevesk    46: #include <paths.h>
1.206     stevesk    47: #include <pwd.h>
1.195     stevesk    48: #include <signal.h>
1.215     stevesk    49: #include <stdio.h>
1.214     stevesk    50: #include <stdlib.h>
1.212     stevesk    51: #include <string.h>
1.211     stevesk    52: #include <unistd.h>
1.1       markus     53:
1.216     deraadt    54: #include "xmalloc.h"
1.51      markus     55: #include "ssh.h"
                     56: #include "ssh1.h"
                     57: #include "ssh2.h"
1.59      djm        58: #include "sshpty.h"
1.1       markus     59: #include "packet.h"
                     60: #include "buffer.h"
1.173     djm        61: #include "match.h"
1.1       markus     62: #include "uidswap.h"
                     63: #include "compat.h"
1.78      markus     64: #include "channels.h"
1.216     deraadt    65: #include "key.h"
                     66: #include "cipher.h"
                     67: #include "kex.h"
                     68: #include "hostfile.h"
1.2       markus     69: #include "auth.h"
1.19      markus     70: #include "auth-options.h"
1.50      markus     71: #include "pathnames.h"
1.51      markus     72: #include "log.h"
                     73: #include "servconf.h"
1.59      djm        74: #include "sshlogin.h"
1.51      markus     75: #include "serverloop.h"
                     76: #include "canohost.h"
1.226     djm        77: #include "misc.h"
1.55      itojun     78: #include "session.h"
1.216     deraadt    79: #ifdef GSSAPI
                     80: #include "ssh-gss.h"
                     81: #endif
1.130     provos     82: #include "monitor_wrap.h"
1.225     markus     83: #include "sftp.h"
1.171     markus     84:
                     85: #ifdef KRB5
                     86: #include <kafs.h>
1.161     markus     87: #endif
                     88:
1.1       markus     89: /* func */
                     90:
                     91: Session *session_new(void);
1.94      itojun     92: void   session_set_fds(Session *, int, int, int);
1.165     markus     93: void   session_pty_cleanup(Session *);
1.94      itojun     94: void   session_proctitle(Session *);
                     95: int    session_setup_x11fwd(Session *);
                     96: void   do_exec_pty(Session *, const char *);
                     97: void   do_exec_no_pty(Session *, const char *);
                     98: void   do_exec(Session *, const char *);
                     99: void   do_login(Session *, const char *);
                    100: void   do_child(Session *, const char *);
1.73      djm       101: void   do_motd(void);
1.94      itojun    102: int    check_quietlogin(Session *, const char *);
1.1       markus    103:
1.94      itojun    104: static void do_authenticated1(Authctxt *);
                    105: static void do_authenticated2(Authctxt *);
                    106:
                    107: static int session_pty_req(Session *);
1.65      markus    108:
1.1       markus    109: /* import */
                    110: extern ServerOptions options;
                    111: extern char *__progname;
                    112: extern int log_stderr;
                    113: extern int debug_flag;
1.45      markus    114: extern u_int utmp_len;
1.21      markus    115: extern int startup_pipe;
1.74      markus    116: extern void destroy_sensitive_data(void);
1.179     dtucker   117: extern Buffer loginmsg;
1.21      markus    118:
1.34      markus    119: /* original command from peer. */
1.92      markus    120: const char *original_command = NULL;
1.34      markus    121:
1.1       markus    122: /* data */
                    123: #define MAX_SESSIONS 10
                    124: Session        sessions[MAX_SESSIONS];
                    125:
1.225     markus    126: #define SUBSYSTEM_NONE         0
                    127: #define SUBSYSTEM_EXT          1
                    128: #define SUBSYSTEM_INT_SFTP     2
                    129:
1.129     provos    130: login_cap_t *lc;
1.28      millert   131:
1.165     markus    132: static int is_child = 0;
                    133:
1.136     markus    134: /* Name and directory of socket for authentication agent forwarding. */
                    135: static char *auth_sock_name = NULL;
                    136: static char *auth_sock_dir = NULL;
                    137:
                    138: /* removes the agent forwarding socket */
                    139:
                    140: static void
1.165     markus    141: auth_sock_cleanup_proc(struct passwd *pw)
1.136     markus    142: {
                    143:        if (auth_sock_name != NULL) {
                    144:                temporarily_use_uid(pw);
                    145:                unlink(auth_sock_name);
                    146:                rmdir(auth_sock_dir);
                    147:                auth_sock_name = NULL;
                    148:                restore_uid();
                    149:        }
                    150: }
                    151:
                    152: static int
                    153: auth_input_request_forwarding(struct passwd * pw)
                    154: {
                    155:        Channel *nc;
                    156:        int sock;
                    157:        struct sockaddr_un sunaddr;
                    158:
                    159:        if (auth_sock_name != NULL) {
                    160:                error("authentication forwarding requested twice.");
                    161:                return 0;
                    162:        }
                    163:
                    164:        /* Temporarily drop privileged uid for mkdir/bind. */
                    165:        temporarily_use_uid(pw);
                    166:
                    167:        /* Allocate a buffer for the socket name, and format the name. */
                    168:        auth_sock_name = xmalloc(MAXPATHLEN);
                    169:        auth_sock_dir = xmalloc(MAXPATHLEN);
1.166     markus    170:        strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
1.136     markus    171:
                    172:        /* Create private directory for socket */
                    173:        if (mkdtemp(auth_sock_dir) == NULL) {
                    174:                packet_send_debug("Agent forwarding disabled: "
                    175:                    "mkdtemp() failed: %.100s", strerror(errno));
                    176:                restore_uid();
                    177:                xfree(auth_sock_name);
                    178:                xfree(auth_sock_dir);
                    179:                auth_sock_name = NULL;
                    180:                auth_sock_dir = NULL;
                    181:                return 0;
                    182:        }
1.137     mpech     183:        snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
                    184:                 auth_sock_dir, (long) getpid());
1.136     markus    185:
                    186:        /* Create the socket. */
                    187:        sock = socket(AF_UNIX, SOCK_STREAM, 0);
                    188:        if (sock < 0)
                    189:                packet_disconnect("socket: %.100s", strerror(errno));
                    190:
                    191:        /* Bind it to the name. */
                    192:        memset(&sunaddr, 0, sizeof(sunaddr));
                    193:        sunaddr.sun_family = AF_UNIX;
                    194:        strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
                    195:
1.200     deraadt   196:        if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0)
1.136     markus    197:                packet_disconnect("bind: %.100s", strerror(errno));
                    198:
                    199:        /* Restore the privileged uid. */
                    200:        restore_uid();
                    201:
                    202:        /* Start listening on the socket. */
1.169     markus    203:        if (listen(sock, SSH_LISTEN_BACKLOG) < 0)
1.136     markus    204:                packet_disconnect("listen: %.100s", strerror(errno));
                    205:
                    206:        /* Allocate a channel for the authentication agent socket. */
                    207:        nc = channel_new("auth socket",
                    208:            SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
                    209:            CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1.156     markus    210:            0, "auth socket", 1);
1.136     markus    211:        strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
                    212:        return 1;
                    213: }
                    214:
1.179     dtucker   215: static void
                    216: display_loginmsg(void)
                    217: {
1.183     djm       218:        if (buffer_len(&loginmsg) > 0) {
                    219:                buffer_append(&loginmsg, "\0", 1);
                    220:                printf("%s", (char *)buffer_ptr(&loginmsg));
                    221:                buffer_clear(&loginmsg);
                    222:        }
1.179     dtucker   223: }
1.136     markus    224:
1.65      markus    225: void
                    226: do_authenticated(Authctxt *authctxt)
                    227: {
1.153     markus    228:        setproctitle("%s", authctxt->pw->pw_name);
                    229:
1.65      markus    230:        /* setup the channel layer */
                    231:        if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
                    232:                channel_permit_all_opens();
                    233:
                    234:        if (compat20)
                    235:                do_authenticated2(authctxt);
                    236:        else
                    237:                do_authenticated1(authctxt);
1.79      markus    238:
1.165     markus    239:        do_cleanup(authctxt);
1.65      markus    240: }
                    241:
1.1       markus    242: /*
                    243:  * Prepares for an interactive session.  This is called after the user has
                    244:  * been successfully authenticated.  During this message exchange, pseudo
                    245:  * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
                    246:  * are requested, etc.
                    247:  */
1.94      itojun    248: static void
1.65      markus    249: do_authenticated1(Authctxt *authctxt)
1.1       markus    250: {
                    251:        Session *s;
1.65      markus    252:        char *command;
1.117     markus    253:        int success, type, screen_flag;
1.139     deraadt   254:        int enable_compression_after_reply = 0;
                    255:        u_int proto_len, data_len, dlen, compression_level = 0;
1.1       markus    256:
1.61      markus    257:        s = session_new();
1.181     markus    258:        if (s == NULL) {
                    259:                error("no more sessions");
                    260:                return;
                    261:        }
1.96      dugsong   262:        s->authctxt = authctxt;
1.65      markus    263:        s->pw = authctxt->pw;
1.28      millert   264:
1.1       markus    265:        /*
                    266:         * We stay in this loop until the client requests to execute a shell
                    267:         * or a command.
                    268:         */
                    269:        for (;;) {
1.65      markus    270:                success = 0;
1.1       markus    271:
                    272:                /* Get a packet from the client. */
1.117     markus    273:                type = packet_read();
1.1       markus    274:
                    275:                /* Process the packet. */
                    276:                switch (type) {
                    277:                case SSH_CMSG_REQUEST_COMPRESSION:
                    278:                        compression_level = packet_get_int();
1.116     markus    279:                        packet_check_eom();
1.1       markus    280:                        if (compression_level < 1 || compression_level > 9) {
1.180     markus    281:                                packet_send_debug("Received invalid compression level %d.",
1.112     deraadt   282:                                    compression_level);
1.138     markus    283:                                break;
                    284:                        }
1.186     markus    285:                        if (options.compression == COMP_NONE) {
1.138     markus    286:                                debug2("compression disabled");
1.1       markus    287:                                break;
                    288:                        }
                    289:                        /* Enable compression after we have responded with SUCCESS. */
                    290:                        enable_compression_after_reply = 1;
                    291:                        success = 1;
                    292:                        break;
                    293:
                    294:                case SSH_CMSG_REQUEST_PTY:
1.86      markus    295:                        success = session_pty_req(s);
1.1       markus    296:                        break;
                    297:
                    298:                case SSH_CMSG_X11_REQUEST_FORWARDING:
                    299:                        s->auth_proto = packet_get_string(&proto_len);
                    300:                        s->auth_data = packet_get_string(&data_len);
                    301:
1.57      markus    302:                        screen_flag = packet_get_protocol_flags() &
                    303:                            SSH_PROTOFLAG_SCREEN_NUMBER;
                    304:                        debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
                    305:
                    306:                        if (packet_remaining() == 4) {
                    307:                                if (!screen_flag)
                    308:                                        debug2("Buggy client: "
                    309:                                            "X11 screen flag missing");
1.1       markus    310:                                s->screen = packet_get_int();
1.56      markus    311:                        } else {
1.1       markus    312:                                s->screen = 0;
1.56      markus    313:                        }
1.116     markus    314:                        packet_check_eom();
1.81      markus    315:                        success = session_setup_x11fwd(s);
                    316:                        if (!success) {
                    317:                                xfree(s->auth_proto);
                    318:                                xfree(s->auth_data);
1.84      markus    319:                                s->auth_proto = NULL;
                    320:                                s->auth_data = NULL;
1.1       markus    321:                        }
                    322:                        break;
                    323:
                    324:                case SSH_CMSG_AGENT_REQUEST_FORWARDING:
                    325:                        if (no_agent_forwarding_flag || compat13) {
                    326:                                debug("Authentication agent forwarding not permitted for this authentication.");
                    327:                                break;
                    328:                        }
                    329:                        debug("Received authentication agent forwarding request.");
1.65      markus    330:                        success = auth_input_request_forwarding(s->pw);
1.1       markus    331:                        break;
                    332:
                    333:                case SSH_CMSG_PORT_FORWARD_REQUEST:
                    334:                        if (no_port_forwarding_flag) {
                    335:                                debug("Port forwarding not permitted for this authentication.");
1.39      markus    336:                                break;
                    337:                        }
                    338:                        if (!options.allow_tcp_forwarding) {
                    339:                                debug("Port forwarding not permitted.");
1.1       markus    340:                                break;
                    341:                        }
                    342:                        debug("Received TCP/IP port forwarding request.");
1.208     markus    343:                        if (channel_input_port_forward_request(s->pw->pw_uid == 0,
                    344:                            options.gateway_ports) < 0) {
                    345:                                debug("Port forwarding failed.");
                    346:                                break;
                    347:                        }
1.1       markus    348:                        success = 1;
                    349:                        break;
                    350:
                    351:                case SSH_CMSG_MAX_PACKET_SIZE:
                    352:                        if (packet_set_maxsize(packet_get_int()) > 0)
                    353:                                success = 1;
                    354:                        break;
                    355:
                    356:                case SSH_CMSG_EXEC_SHELL:
                    357:                case SSH_CMSG_EXEC_CMD:
                    358:                        if (type == SSH_CMSG_EXEC_CMD) {
                    359:                                command = packet_get_string(&dlen);
                    360:                                debug("Exec command '%.500s'", command);
1.92      markus    361:                                do_exec(s, command);
                    362:                                xfree(command);
1.1       markus    363:                        } else {
1.92      markus    364:                                do_exec(s, NULL);
1.1       markus    365:                        }
1.116     markus    366:                        packet_check_eom();
1.82      markus    367:                        session_close(s);
1.1       markus    368:                        return;
                    369:
                    370:                default:
                    371:                        /*
                    372:                         * Any unknown messages in this phase are ignored,
                    373:                         * and a failure message is returned.
                    374:                         */
1.155     itojun    375:                        logit("Unknown packet type received after authentication: %d", type);
1.1       markus    376:                }
                    377:                packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
                    378:                packet_send();
                    379:                packet_write_wait();
                    380:
                    381:                /* Enable compression now that we have replied if appropriate. */
                    382:                if (enable_compression_after_reply) {
                    383:                        enable_compression_after_reply = 0;
                    384:                        packet_start_compression(compression_level);
                    385:                }
                    386:        }
                    387: }
                    388:
                    389: /*
                    390:  * This is called to fork and execute a command when we have no tty.  This
                    391:  * will call do_child from the child, and server_loop from the parent after
                    392:  * setting up file descriptors and such.
                    393:  */
1.4       markus    394: void
1.63      markus    395: do_exec_no_pty(Session *s, const char *command)
1.1       markus    396: {
1.137     mpech     397:        pid_t pid;
1.1       markus    398:
                    399:        int inout[2], err[2];
                    400:        /* Uses socket pairs to communicate with the program. */
                    401:        if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
                    402:            socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
                    403:                packet_disconnect("Could not create socket pairs: %.100s",
                    404:                                  strerror(errno));
                    405:        if (s == NULL)
                    406:                fatal("do_exec_no_pty: no session");
                    407:
1.9       markus    408:        session_proctitle(s);
1.1       markus    409:
                    410:        /* Fork the child. */
                    411:        if ((pid = fork()) == 0) {
1.165     markus    412:                is_child = 1;
1.144     markus    413:
1.1       markus    414:                /* Child.  Reinitialize the log since the pid has changed. */
                    415:                log_init(__progname, options.log_level, options.log_facility, log_stderr);
                    416:
                    417:                /*
                    418:                 * Create a new session and process group since the 4.4BSD
                    419:                 * setlogin() affects the entire process group.
                    420:                 */
                    421:                if (setsid() < 0)
                    422:                        error("setsid failed: %.100s", strerror(errno));
                    423:
                    424:                /*
                    425:                 * Redirect stdin, stdout, and stderr.  Stdin and stdout will
                    426:                 * use the same socket, as some programs (particularly rdist)
                    427:                 * seem to depend on it.
                    428:                 */
                    429:                close(inout[1]);
                    430:                close(err[1]);
                    431:                if (dup2(inout[0], 0) < 0)      /* stdin */
                    432:                        perror("dup2 stdin");
                    433:                if (dup2(inout[0], 1) < 0)      /* stdout.  Note: same socket as stdin. */
                    434:                        perror("dup2 stdout");
                    435:                if (dup2(err[0], 2) < 0)        /* stderr */
                    436:                        perror("dup2 stderr");
                    437:
                    438:                /* Do processing for the child (exec command etc). */
1.60      markus    439:                do_child(s, command);
1.1       markus    440:                /* NOTREACHED */
                    441:        }
                    442:        if (pid < 0)
                    443:                packet_disconnect("fork failed: %.100s", strerror(errno));
                    444:        s->pid = pid;
1.47      markus    445:        /* Set interactive/non-interactive mode. */
1.48      markus    446:        packet_set_interactive(s->display != NULL);
1.1       markus    447:
                    448:        /* We are the parent.  Close the child sides of the socket pairs. */
                    449:        close(inout[0]);
                    450:        close(err[0]);
                    451:
                    452:        /*
                    453:         * Enter the interactive session.  Note: server_loop must be able to
                    454:         * handle the case that fdin and fdout are the same.
                    455:         */
1.2       markus    456:        if (compat20) {
1.64      markus    457:                session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
1.2       markus    458:        } else {
                    459:                server_loop(pid, inout[1], inout[1], err[1]);
                    460:                /* server_loop has closed inout[1] and err[1]. */
                    461:        }
1.1       markus    462: }
                    463:
                    464: /*
                    465:  * This is called to fork and execute a command when we have a tty.  This
                    466:  * will call do_child from the child, and server_loop from the parent after
                    467:  * setting up file descriptors, controlling tty, updating wtmp, utmp,
                    468:  * lastlog, and other such operations.
                    469:  */
1.4       markus    470: void
1.63      markus    471: do_exec_pty(Session *s, const char *command)
1.1       markus    472: {
                    473:        int fdout, ptyfd, ttyfd, ptymaster;
                    474:        pid_t pid;
                    475:
                    476:        if (s == NULL)
                    477:                fatal("do_exec_pty: no session");
                    478:        ptyfd = s->ptyfd;
                    479:        ttyfd = s->ttyfd;
                    480:
                    481:        /* Fork the child. */
                    482:        if ((pid = fork()) == 0) {
1.165     markus    483:                is_child = 1;
1.97      markus    484:
1.24      markus    485:                /* Child.  Reinitialize the log because the pid has changed. */
1.1       markus    486:                log_init(__progname, options.log_level, options.log_facility, log_stderr);
                    487:                /* Close the master side of the pseudo tty. */
                    488:                close(ptyfd);
                    489:
                    490:                /* Make the pseudo tty our controlling tty. */
                    491:                pty_make_controlling_tty(&ttyfd, s->tty);
                    492:
1.103     markus    493:                /* Redirect stdin/stdout/stderr from the pseudo tty. */
                    494:                if (dup2(ttyfd, 0) < 0)
                    495:                        error("dup2 stdin: %s", strerror(errno));
                    496:                if (dup2(ttyfd, 1) < 0)
                    497:                        error("dup2 stdout: %s", strerror(errno));
                    498:                if (dup2(ttyfd, 2) < 0)
                    499:                        error("dup2 stderr: %s", strerror(errno));
1.1       markus    500:
                    501:                /* Close the extra descriptor for the pseudo tty. */
                    502:                close(ttyfd);
                    503:
1.24      markus    504:                /* record login, etc. similar to login(1) */
1.41      markus    505:                if (!(options.use_login && command == NULL))
                    506:                        do_login(s, command);
1.228     djm       507:
1.1       markus    508:                /* Do common processing for the child, such as execing the command. */
1.60      markus    509:                do_child(s, command);
1.1       markus    510:                /* NOTREACHED */
                    511:        }
                    512:        if (pid < 0)
                    513:                packet_disconnect("fork failed: %.100s", strerror(errno));
                    514:        s->pid = pid;
                    515:
                    516:        /* Parent.  Close the slave side of the pseudo tty. */
                    517:        close(ttyfd);
                    518:
                    519:        /*
                    520:         * Create another descriptor of the pty master side for use as the
                    521:         * standard input.  We could use the original descriptor, but this
                    522:         * simplifies code in server_loop.  The descriptor is bidirectional.
                    523:         */
                    524:        fdout = dup(ptyfd);
                    525:        if (fdout < 0)
                    526:                packet_disconnect("dup #1 failed: %.100s", strerror(errno));
                    527:
                    528:        /* we keep a reference to the pty master */
                    529:        ptymaster = dup(ptyfd);
                    530:        if (ptymaster < 0)
                    531:                packet_disconnect("dup #2 failed: %.100s", strerror(errno));
                    532:        s->ptymaster = ptymaster;
                    533:
                    534:        /* Enter interactive session. */
1.47      markus    535:        packet_set_interactive(1);
1.2       markus    536:        if (compat20) {
                    537:                session_set_fds(s, ptyfd, fdout, -1);
                    538:        } else {
                    539:                server_loop(pid, ptyfd, fdout, -1);
                    540:                /* server_loop _has_ closed ptyfd and fdout. */
1.24      markus    541:        }
                    542: }
                    543:
1.90      markus    544: /*
                    545:  * This is called to fork and execute a command.  If another command is
                    546:  * to be forced, execute that instead.
                    547:  */
                    548: void
                    549: do_exec(Session *s, const char *command)
                    550: {
1.210     dtucker   551:        if (options.adm_forced_command) {
                    552:                original_command = command;
                    553:                command = options.adm_forced_command;
1.226     djm       554:                if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
                    555:                        s->is_subsystem = SUBSYSTEM_INT_SFTP;
                    556:                else if (s->is_subsystem)
1.225     markus    557:                        s->is_subsystem = SUBSYSTEM_EXT;
1.210     dtucker   558:                debug("Forced command (config) '%.900s'", command);
                    559:        } else if (forced_command) {
1.90      markus    560:                original_command = command;
                    561:                command = forced_command;
1.226     djm       562:                if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
                    563:                        s->is_subsystem = SUBSYSTEM_INT_SFTP;
                    564:                else if (s->is_subsystem)
1.225     markus    565:                        s->is_subsystem = SUBSYSTEM_EXT;
1.210     dtucker   566:                debug("Forced command (key option) '%.900s'", command);
1.90      markus    567:        }
1.163     markus    568:
                    569: #ifdef GSSAPI
                    570:        if (options.gss_authentication) {
                    571:                temporarily_use_uid(s->pw);
                    572:                ssh_gssapi_storecreds();
                    573:                restore_uid();
                    574:        }
                    575: #endif
1.90      markus    576:        if (s->ttyfd != -1)
                    577:                do_exec_pty(s, command);
                    578:        else
                    579:                do_exec_no_pty(s, command);
                    580:
1.92      markus    581:        original_command = NULL;
1.179     dtucker   582:
                    583:        /*
                    584:         * Clear loginmsg: it's the child's responsibility to display
                    585:         * it to the user, otherwise multiple sessions may accumulate
                    586:         * multiple copies of the login messages.
                    587:         */
                    588:        buffer_clear(&loginmsg);
1.90      markus    589: }
                    590:
                    591:
1.24      markus    592: /* administrative, login(1)-like work */
                    593: void
1.41      markus    594: do_login(Session *s, const char *command)
1.24      markus    595: {
                    596:        socklen_t fromlen;
                    597:        struct sockaddr_storage from;
                    598:        struct passwd * pw = s->pw;
                    599:        pid_t pid = getpid();
                    600:
                    601:        /*
                    602:         * Get IP address of client. If the connection is not a socket, let
                    603:         * the address be 0.0.0.0.
                    604:         */
                    605:        memset(&from, 0, sizeof(from));
1.148     stevesk   606:        fromlen = sizeof(from);
1.24      markus    607:        if (packet_connection_is_on_socket()) {
                    608:                if (getpeername(packet_get_connection_in(),
1.200     deraadt   609:                    (struct sockaddr *)&from, &fromlen) < 0) {
1.24      markus    610:                        debug("getpeername: %.100s", strerror(errno));
1.165     markus    611:                        cleanup_exit(255);
1.24      markus    612:                }
                    613:        }
1.25      markus    614:
1.24      markus    615:        /* Record that there was a login on that tty from the remote host. */
1.133     markus    616:        if (!use_privsep)
                    617:                record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
                    618:                    get_remote_name_or_ip(utmp_len,
1.158     markus    619:                    options.use_dns),
1.148     stevesk   620:                    (struct sockaddr *)&from, fromlen);
1.24      markus    621:
1.73      djm       622:        if (check_quietlogin(s, command))
1.24      markus    623:                return;
1.73      djm       624:
1.179     dtucker   625:        display_loginmsg();
1.73      djm       626:
                    627:        do_motd();
                    628: }
                    629:
                    630: /*
                    631:  * Display the message of the day.
                    632:  */
                    633: void
                    634: do_motd(void)
                    635: {
                    636:        FILE *f;
                    637:        char buf[256];
                    638:
1.24      markus    639:        if (options.print_motd) {
1.28      millert   640:                f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
                    641:                    "/etc/motd"), "r");
1.24      markus    642:                if (f) {
                    643:                        while (fgets(buf, sizeof(buf), f))
                    644:                                fputs(buf, stdout);
                    645:                        fclose(f);
                    646:                }
1.2       markus    647:        }
1.73      djm       648: }
                    649:
                    650:
                    651: /*
                    652:  * Check for quiet login, either .hushlogin or command given.
                    653:  */
                    654: int
                    655: check_quietlogin(Session *s, const char *command)
                    656: {
                    657:        char buf[256];
1.96      dugsong   658:        struct passwd *pw = s->pw;
1.73      djm       659:        struct stat st;
                    660:
                    661:        /* Return 1 if .hushlogin exists or a command given. */
                    662:        if (command != NULL)
                    663:                return 1;
                    664:        snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
                    665:        if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
                    666:                return 1;
                    667:        return 0;
1.1       markus    668: }
                    669:
                    670: /*
                    671:  * Sets the value of the given variable in the environment.  If the variable
                    672:  * already exists, its value is overriden.
                    673:  */
1.161     markus    674: void
1.45      markus    675: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112     deraadt   676:        const char *value)
1.1       markus    677: {
1.164     markus    678:        char **env;
                    679:        u_int envsize;
1.45      markus    680:        u_int i, namelen;
1.1       markus    681:
                    682:        /*
                    683:         * Find the slot where the value should be stored.  If the variable
                    684:         * already exists, we reuse the slot; otherwise we append a new slot
                    685:         * at the end of the array, expanding if necessary.
                    686:         */
                    687:        env = *envp;
                    688:        namelen = strlen(name);
                    689:        for (i = 0; env[i]; i++)
                    690:                if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
                    691:                        break;
                    692:        if (env[i]) {
                    693:                /* Reuse the slot. */
                    694:                xfree(env[i]);
                    695:        } else {
                    696:                /* New variable.  Expand if necessary. */
1.164     markus    697:                envsize = *envsizep;
                    698:                if (i >= envsize - 1) {
                    699:                        if (envsize >= 1000)
                    700:                                fatal("child_set_env: too many env vars");
                    701:                        envsize += 50;
1.201     djm       702:                        env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1.164     markus    703:                        *envsizep = envsize;
1.1       markus    704:                }
                    705:                /* Need to set the NULL pointer at end of array beyond the new slot. */
                    706:                env[i + 1] = NULL;
                    707:        }
                    708:
                    709:        /* Allocate space and format the variable in the appropriate slot. */
                    710:        env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
                    711:        snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
                    712: }
                    713:
                    714: /*
                    715:  * Reads environment variables from the given file and adds/overrides them
                    716:  * into the environment.  If the file does not exist, this does nothing.
                    717:  * Otherwise, it must consist of empty lines, comments (line starts with '#')
                    718:  * and assignments of the form name=value.  No other forms are allowed.
                    719:  */
1.94      itojun    720: static void
1.45      markus    721: read_environment_file(char ***env, u_int *envsize,
1.112     deraadt   722:        const char *filename)
1.1       markus    723: {
                    724:        FILE *f;
                    725:        char buf[4096];
                    726:        char *cp, *value;
1.142     deraadt   727:        u_int lineno = 0;
1.1       markus    728:
                    729:        f = fopen(filename, "r");
                    730:        if (!f)
                    731:                return;
                    732:
                    733:        while (fgets(buf, sizeof(buf), f)) {
1.142     deraadt   734:                if (++lineno > 1000)
                    735:                        fatal("Too many lines in environment file %s", filename);
1.1       markus    736:                for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
                    737:                        ;
                    738:                if (!*cp || *cp == '#' || *cp == '\n')
                    739:                        continue;
1.224     gilles    740:
                    741:                cp[strcspn(cp, "\n")] = '\0';
                    742:
1.1       markus    743:                value = strchr(cp, '=');
                    744:                if (value == NULL) {
1.142     deraadt   745:                        fprintf(stderr, "Bad line %u in %.100s\n", lineno,
                    746:                            filename);
1.1       markus    747:                        continue;
                    748:                }
1.14      deraadt   749:                /*
                    750:                 * Replace the equals sign by nul, and advance value to
                    751:                 * the value string.
                    752:                 */
1.1       markus    753:                *value = '\0';
                    754:                value++;
                    755:                child_set_env(env, envsize, cp, value);
                    756:        }
                    757:        fclose(f);
                    758: }
                    759:
1.127     markus    760: static char **
                    761: do_setup_env(Session *s, const char *shell)
1.1       markus    762: {
                    763:        char buf[256];
1.127     markus    764:        u_int i, envsize;
1.154     markus    765:        char **env, *laddr;
1.127     markus    766:        struct passwd *pw = s->pw;
1.1       markus    767:
                    768:        /* Initialize the environment. */
                    769:        envsize = 100;
1.220     djm       770:        env = xcalloc(envsize, sizeof(char *));
1.1       markus    771:        env[0] = NULL;
                    772:
1.161     markus    773: #ifdef GSSAPI
1.168     djm       774:        /* Allow any GSSAPI methods that we've used to alter
1.161     markus    775:         * the childs environment as they see fit
                    776:         */
                    777:        ssh_gssapi_do_child(&env, &envsize);
                    778: #endif
                    779:
1.1       markus    780:        if (!options.use_login) {
                    781:                /* Set basic environment. */
1.173     djm       782:                for (i = 0; i < s->num_env; i++)
1.178     deraadt   783:                        child_set_env(&env, &envsize, s->env[i].name,
1.173     djm       784:                            s->env[i].val);
                    785:
1.1       markus    786:                child_set_env(&env, &envsize, "USER", pw->pw_name);
                    787:                child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
                    788:                child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145     markus    789:                if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
                    790:                        child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
                    791:                else
                    792:                        child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1       markus    793:
                    794:                snprintf(buf, sizeof buf, "%.200s/%.50s",
                    795:                         _PATH_MAILDIR, pw->pw_name);
                    796:                child_set_env(&env, &envsize, "MAIL", buf);
                    797:
                    798:                /* Normal systems set SHELL by default. */
                    799:                child_set_env(&env, &envsize, "SHELL", shell);
                    800:        }
                    801:        if (getenv("TZ"))
                    802:                child_set_env(&env, &envsize, "TZ", getenv("TZ"));
                    803:
                    804:        /* Set custom environment options from RSA authentication. */
1.110     markus    805:        if (!options.use_login) {
                    806:                while (custom_environment) {
                    807:                        struct envstring *ce = custom_environment;
1.143     deraadt   808:                        char *str = ce->s;
1.127     markus    809:
1.143     deraadt   810:                        for (i = 0; str[i] != '=' && str[i]; i++)
1.110     markus    811:                                ;
1.143     deraadt   812:                        if (str[i] == '=') {
                    813:                                str[i] = 0;
                    814:                                child_set_env(&env, &envsize, str, str + i + 1);
1.110     markus    815:                        }
                    816:                        custom_environment = ce->next;
                    817:                        xfree(ce->s);
                    818:                        xfree(ce);
1.1       markus    819:                }
                    820:        }
                    821:
1.149     stevesk   822:        /* SSH_CLIENT deprecated */
1.1       markus    823:        snprintf(buf, sizeof buf, "%.50s %d %d",
1.127     markus    824:            get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1       markus    825:        child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149     stevesk   826:
1.154     markus    827:        laddr = get_local_ipaddr(packet_get_connection_in());
1.149     stevesk   828:        snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154     markus    829:            get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
                    830:        xfree(laddr);
1.149     stevesk   831:        child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1       markus    832:
1.60      markus    833:        if (s->ttyfd != -1)
                    834:                child_set_env(&env, &envsize, "SSH_TTY", s->tty);
                    835:        if (s->term)
                    836:                child_set_env(&env, &envsize, "TERM", s->term);
                    837:        if (s->display)
                    838:                child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34      markus    839:        if (original_command)
                    840:                child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
                    841:                    original_command);
1.96      dugsong   842: #ifdef KRB5
                    843:        if (s->authctxt->krb5_ticket_file)
                    844:                child_set_env(&env, &envsize, "KRB5CCNAME",
1.112     deraadt   845:                    s->authctxt->krb5_ticket_file);
1.96      dugsong   846: #endif
1.136     markus    847:        if (auth_sock_name != NULL)
1.1       markus    848:                child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136     markus    849:                    auth_sock_name);
1.1       markus    850:
                    851:        /* read $HOME/.ssh/environment. */
1.146     markus    852:        if (options.permit_user_env && !options.use_login) {
1.14      deraadt   853:                snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
                    854:                    pw->pw_dir);
1.1       markus    855:                read_environment_file(&env, &envsize, buf);
                    856:        }
                    857:        if (debug_flag) {
                    858:                /* dump the environment */
                    859:                fprintf(stderr, "Environment:\n");
                    860:                for (i = 0; env[i]; i++)
                    861:                        fprintf(stderr, "  %.200s\n", env[i]);
                    862:        }
1.127     markus    863:        return env;
                    864: }
                    865:
                    866: /*
                    867:  * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
                    868:  * first in this order).
                    869:  */
                    870: static void
                    871: do_rc_files(Session *s, const char *shell)
                    872: {
                    873:        FILE *f = NULL;
                    874:        char cmd[1024];
                    875:        int do_xauth;
                    876:        struct stat st;
                    877:
                    878:        do_xauth =
                    879:            s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
                    880:
1.230.2.1! brad      881:        /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
        !           882:        if (!s->is_subsystem && options.adm_forced_command == NULL &&
        !           883:            (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1.127     markus    884:                snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
                    885:                    shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
                    886:                if (debug_flag)
                    887:                        fprintf(stderr, "Running %s\n", cmd);
                    888:                f = popen(cmd, "w");
                    889:                if (f) {
                    890:                        if (do_xauth)
                    891:                                fprintf(f, "%s %s\n", s->auth_proto,
                    892:                                    s->auth_data);
                    893:                        pclose(f);
                    894:                } else
                    895:                        fprintf(stderr, "Could not run %s\n",
                    896:                            _PATH_SSH_USER_RC);
                    897:        } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
                    898:                if (debug_flag)
                    899:                        fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
                    900:                            _PATH_SSH_SYSTEM_RC);
                    901:                f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
                    902:                if (f) {
                    903:                        if (do_xauth)
                    904:                                fprintf(f, "%s %s\n", s->auth_proto,
                    905:                                    s->auth_data);
                    906:                        pclose(f);
                    907:                } else
                    908:                        fprintf(stderr, "Could not run %s\n",
                    909:                            _PATH_SSH_SYSTEM_RC);
                    910:        } else if (do_xauth && options.xauth_location != NULL) {
                    911:                /* Add authority data to .Xauthority if appropriate. */
                    912:                if (debug_flag) {
                    913:                        fprintf(stderr,
1.151     stevesk   914:                            "Running %.500s remove %.100s\n",
1.165     markus    915:                            options.xauth_location, s->auth_display);
1.151     stevesk   916:                        fprintf(stderr,
                    917:                            "%.500s add %.100s %.100s %.100s\n",
1.127     markus    918:                            options.xauth_location, s->auth_display,
                    919:                            s->auth_proto, s->auth_data);
                    920:                }
                    921:                snprintf(cmd, sizeof cmd, "%s -q -",
                    922:                    options.xauth_location);
                    923:                f = popen(cmd, "w");
                    924:                if (f) {
1.151     stevesk   925:                        fprintf(f, "remove %s\n",
                    926:                            s->auth_display);
1.127     markus    927:                        fprintf(f, "add %s %s %s\n",
                    928:                            s->auth_display, s->auth_proto,
                    929:                            s->auth_data);
                    930:                        pclose(f);
                    931:                } else {
                    932:                        fprintf(stderr, "Could not run %s\n",
                    933:                            cmd);
                    934:                }
                    935:        }
                    936: }
                    937:
                    938: static void
                    939: do_nologin(struct passwd *pw)
                    940: {
                    941:        FILE *f = NULL;
                    942:        char buf[1024];
                    943:
                    944:        if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
                    945:                f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
                    946:                    _PATH_NOLOGIN), "r");
                    947:        if (f) {
                    948:                /* /etc/nologin exists.  Print its contents and exit. */
1.155     itojun    949:                logit("User %.100s not allowed because %s exists",
1.150     stevesk   950:                    pw->pw_name, _PATH_NOLOGIN);
1.127     markus    951:                while (fgets(buf, sizeof(buf), f))
                    952:                        fputs(buf, stderr);
                    953:                fclose(f);
                    954:                exit(254);
                    955:        }
                    956: }
                    957:
1.226     djm       958: /*
                    959:  * Chroot into a directory after checking it for safety: all path components
                    960:  * must be root-owned directories with strict permissions.
                    961:  */
                    962: static void
                    963: safely_chroot(const char *path, uid_t uid)
                    964: {
                    965:        const char *cp;
                    966:        char component[MAXPATHLEN];
                    967:        struct stat st;
                    968:
                    969:        if (*path != '/')
                    970:                fatal("chroot path does not begin at root");
                    971:        if (strlen(path) >= sizeof(component))
                    972:                fatal("chroot path too long");
                    973:
                    974:        /*
                    975:         * Descend the path, checking that each component is a
                    976:         * root-owned directory with strict permissions.
                    977:         */
                    978:        for (cp = path; cp != NULL;) {
                    979:                if ((cp = strchr(cp, '/')) == NULL)
                    980:                        strlcpy(component, path, sizeof(component));
                    981:                else {
                    982:                        cp++;
                    983:                        memcpy(component, path, cp - path);
                    984:                        component[cp - path] = '\0';
                    985:                }
                    986:
                    987:                debug3("%s: checking '%s'", __func__, component);
                    988:
                    989:                if (stat(component, &st) != 0)
                    990:                        fatal("%s: stat(\"%s\"): %s", __func__,
                    991:                            component, strerror(errno));
                    992:                if (st.st_uid != 0 || (st.st_mode & 022) != 0)
                    993:                        fatal("bad ownership or modes for chroot "
                    994:                            "directory %s\"%s\"",
                    995:                            cp == NULL ? "" : "component ", component);
                    996:                if (!S_ISDIR(st.st_mode))
                    997:                        fatal("chroot path %s\"%s\" is not a directory",
                    998:                            cp == NULL ? "" : "component ", component);
                    999:
                   1000:        }
                   1001:
                   1002:        if (chdir(path) == -1)
                   1003:                fatal("Unable to chdir to chroot path \"%s\": "
                   1004:                    "%s", path, strerror(errno));
                   1005:        if (chroot(path) == -1)
                   1006:                fatal("chroot(\"%s\"): %s", path, strerror(errno));
                   1007:        if (chdir("/") == -1)
                   1008:                fatal("%s: chdir(/) after chroot: %s",
                   1009:                    __func__, strerror(errno));
                   1010:        verbose("Changed root directory to \"%s\"", path);
                   1011: }
                   1012:
1.127     markus   1013: /* Set login name, uid, gid, and groups. */
1.130     provos   1014: void
1.127     markus   1015: do_setusercontext(struct passwd *pw)
                   1016: {
1.227     djm      1017:        char *chroot_path, *tmp;
                   1018:
1.127     markus   1019:        if (getuid() == 0 || geteuid() == 0) {
1.226     djm      1020:                /* Prepare groups */
1.127     markus   1021:                if (setusercontext(lc, pw, pw->pw_uid,
1.226     djm      1022:                    (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127     markus   1023:                        perror("unable to set user context");
                   1024:                        exit(1);
                   1025:                }
1.226     djm      1026:
                   1027:                if (options.chroot_directory != NULL &&
                   1028:                    strcasecmp(options.chroot_directory, "none") != 0) {
1.227     djm      1029:                         tmp = tilde_expand_filename(options.chroot_directory,
                   1030:                            pw->pw_uid);
                   1031:                        chroot_path = percent_expand(tmp, "h", pw->pw_dir,
                   1032:                            "u", pw->pw_name, (char *)NULL);
1.226     djm      1033:                        safely_chroot(chroot_path, pw->pw_uid);
1.227     djm      1034:                        free(tmp);
1.226     djm      1035:                        free(chroot_path);
                   1036:                }
                   1037:
                   1038:                /* Set UID */
                   1039:                if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
                   1040:                        perror("unable to set user context (setuser)");
                   1041:                        exit(1);
                   1042:                }
1.127     markus   1043:        }
                   1044:        if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
                   1045:                fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
                   1046: }
                   1047:
1.131     markus   1048: static void
1.172     markus   1049: do_pwchange(Session *s)
                   1050: {
1.179     dtucker  1051:        fflush(NULL);
1.172     markus   1052:        fprintf(stderr, "WARNING: Your password has expired.\n");
                   1053:        if (s->ttyfd != -1) {
1.178     deraadt  1054:                fprintf(stderr,
1.172     markus   1055:                    "You must change your password now and login again!\n");
                   1056:                execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
                   1057:                perror("passwd");
                   1058:        } else {
                   1059:                fprintf(stderr,
                   1060:                    "Password change required but no TTY available.\n");
                   1061:        }
                   1062:        exit(1);
                   1063: }
                   1064:
                   1065: static void
1.130     provos   1066: launch_login(struct passwd *pw, const char *hostname)
                   1067: {
                   1068:        /* Launch login(1). */
                   1069:
                   1070:        execl("/usr/bin/login", "login", "-h", hostname,
                   1071:            "-p", "-f", "--", pw->pw_name, (char *)NULL);
                   1072:
                   1073:        /* Login couldn't be executed, die. */
                   1074:
                   1075:        perror("login");
                   1076:        exit(1);
                   1077: }
                   1078:
1.172     markus   1079: static void
                   1080: child_close_fds(void)
                   1081: {
                   1082:        int i;
                   1083:
                   1084:        if (packet_get_connection_in() == packet_get_connection_out())
                   1085:                close(packet_get_connection_in());
                   1086:        else {
                   1087:                close(packet_get_connection_in());
                   1088:                close(packet_get_connection_out());
                   1089:        }
                   1090:        /*
                   1091:         * Close all descriptors related to channels.  They will still remain
                   1092:         * open in the parent.
                   1093:         */
                   1094:        /* XXX better use close-on-exec? -markus */
                   1095:        channel_close_all();
                   1096:
                   1097:        /*
                   1098:         * Close any extra file descriptors.  Note that there may still be
                   1099:         * descriptors left by system functions.  They will be closed later.
                   1100:         */
                   1101:        endpwent();
                   1102:
                   1103:        /*
1.188     djm      1104:         * Close any extra open file descriptors so that we don't have them
1.172     markus   1105:         * hanging around in clients.  Note that we want to do this after
                   1106:         * initgroups, because at least on Solaris 2.3 it leaves file
                   1107:         * descriptors open.
                   1108:         */
                   1109:        for (i = 3; i < 64; i++)
                   1110:                close(i);
                   1111: }
                   1112:
1.127     markus   1113: /*
                   1114:  * Performs common processing for the child, such as setting up the
                   1115:  * environment, closing extra file descriptors, setting the user and group
                   1116:  * ids, and executing the command or shell.
                   1117:  */
1.225     markus   1118: #define ARGV_MAX 10
1.127     markus   1119: void
                   1120: do_child(Session *s, const char *command)
                   1121: {
                   1122:        extern char **environ;
                   1123:        char **env;
1.225     markus   1124:        char *argv[ARGV_MAX];
1.127     markus   1125:        const char *shell, *shell0, *hostname = NULL;
                   1126:        struct passwd *pw = s->pw;
                   1127:
                   1128:        /* remove hostkey from the child's memory */
                   1129:        destroy_sensitive_data();
                   1130:
1.172     markus   1131:        /* Force a password change */
                   1132:        if (s->authctxt->force_pwchange) {
                   1133:                do_setusercontext(pw);
                   1134:                child_close_fds();
                   1135:                do_pwchange(s);
                   1136:                exit(1);
                   1137:        }
                   1138:
1.127     markus   1139:        /* login(1) is only called if we execute the login shell */
                   1140:        if (options.use_login && command != NULL)
                   1141:                options.use_login = 0;
                   1142:
                   1143:        /*
                   1144:         * Login(1) does this as well, and it needs uid 0 for the "-h"
                   1145:         * switch, so we let login(1) to this for us.
                   1146:         */
                   1147:        if (!options.use_login) {
                   1148:                do_nologin(pw);
                   1149:                do_setusercontext(pw);
                   1150:        }
                   1151:
                   1152:        /*
                   1153:         * Get the shell from the password data.  An empty shell field is
                   1154:         * legal, and means /bin/sh.
                   1155:         */
                   1156:        shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152     markus   1157:
                   1158:        /*
                   1159:         * Make sure $SHELL points to the shell from the password file,
                   1160:         * even if shell is overridden from login.conf
                   1161:         */
                   1162:        env = do_setup_env(s, shell);
                   1163:
1.127     markus   1164:        shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
                   1165:
1.26      millert  1166:        /* we have to stash the hostname before we close our socket. */
                   1167:        if (options.use_login)
1.70      stevesk  1168:                hostname = get_remote_name_or_ip(utmp_len,
1.158     markus   1169:                    options.use_dns);
1.1       markus   1170:        /*
                   1171:         * Close the connection descriptors; note that this is the child, and
                   1172:         * the server will still have the socket open, and it is important
                   1173:         * that we do not shutdown it.  Note that the descriptors cannot be
                   1174:         * closed before building the environment, as we call
                   1175:         * get_remote_ipaddr there.
                   1176:         */
1.172     markus   1177:        child_close_fds();
1.1       markus   1178:
                   1179:        /*
1.125     deraadt  1180:         * Must take new environment into use so that .ssh/rc,
                   1181:         * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1       markus   1182:         */
                   1183:        environ = env;
1.170     jakob    1184:
                   1185: #ifdef KRB5
                   1186:        /*
                   1187:         * At this point, we check to see if AFS is active and if we have
                   1188:         * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
                   1189:         * if we can (and need to) extend the ticket into an AFS token. If
                   1190:         * we don't do this, we run into potential problems if the user's
                   1191:         * home directory is in AFS and it's not world-readable.
                   1192:         */
                   1193:
                   1194:        if (options.kerberos_get_afs_token && k_hasafs() &&
1.185     djm      1195:            (s->authctxt->krb5_ctx != NULL)) {
1.170     jakob    1196:                char cell[64];
                   1197:
                   1198:                debug("Getting AFS token");
                   1199:
                   1200:                k_setpag();
                   1201:
                   1202:                if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
                   1203:                        krb5_afslog(s->authctxt->krb5_ctx,
                   1204:                            s->authctxt->krb5_fwd_ccache, cell, NULL);
                   1205:
                   1206:                krb5_afslog_home(s->authctxt->krb5_ctx,
                   1207:                    s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
                   1208:        }
                   1209: #endif
1.104     markus   1210:
1.188     djm      1211:        /* Change current directory to the user's home directory. */
1.104     markus   1212:        if (chdir(pw->pw_dir) < 0) {
                   1213:                fprintf(stderr, "Could not chdir to home directory %s: %s\n",
                   1214:                    pw->pw_dir, strerror(errno));
                   1215:                if (login_getcapbool(lc, "requirehome", 0))
                   1216:                        exit(1);
                   1217:        }
1.230     djm      1218:
                   1219:        closefrom(STDERR_FILENO + 1);
1.1       markus   1220:
1.127     markus   1221:        if (!options.use_login)
                   1222:                do_rc_files(s, shell);
1.67      markus   1223:
                   1224:        /* restore SIGPIPE for child */
1.217     stevesk  1225:        signal(SIGPIPE, SIG_DFL);
1.67      markus   1226:
1.225     markus   1227:        if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
                   1228:                extern int optind, optreset;
                   1229:                int i;
                   1230:                char *p, *args;
                   1231:
                   1232:                setproctitle("%s@internal-sftp-server", s->pw->pw_name);
                   1233:                args = strdup(command ? command : "sftp-server");
                   1234:                for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
                   1235:                        if (i < ARGV_MAX - 1)
                   1236:                                argv[i++] = p;
                   1237:                argv[i] = NULL;
                   1238:                optind = optreset = 1;
                   1239:                __progname = argv[0];
1.226     djm      1240:                exit(sftp_server_main(i, argv, s->pw));
1.225     markus   1241:        }
                   1242:
1.127     markus   1243:        if (options.use_login) {
1.130     provos   1244:                launch_login(pw, hostname);
                   1245:                /* NEVERREACHED */
1.127     markus   1246:        }
                   1247:
                   1248:        /* Get the last component of the shell name. */
                   1249:        if ((shell0 = strrchr(shell, '/')) != NULL)
                   1250:                shell0++;
                   1251:        else
                   1252:                shell0 = shell;
                   1253:
1.1       markus   1254:        /*
                   1255:         * If we have no command, execute the shell.  In this case, the shell
                   1256:         * name to be passed in argv[0] is preceded by '-' to indicate that
                   1257:         * this is a login shell.
                   1258:         */
                   1259:        if (!command) {
1.127     markus   1260:                char argv0[256];
1.1       markus   1261:
1.127     markus   1262:                /* Start the shell.  Set initial character to '-'. */
                   1263:                argv0[0] = '-';
1.1       markus   1264:
1.127     markus   1265:                if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128     markus   1266:                    >= sizeof(argv0) - 1) {
1.127     markus   1267:                        errno = EINVAL;
1.1       markus   1268:                        perror(shell);
                   1269:                        exit(1);
1.127     markus   1270:                }
1.1       markus   1271:
1.127     markus   1272:                /* Execute the shell. */
                   1273:                argv[0] = argv0;
                   1274:                argv[1] = NULL;
                   1275:                execve(shell, argv, env);
                   1276:
                   1277:                /* Executing the shell failed. */
                   1278:                perror(shell);
                   1279:                exit(1);
1.1       markus   1280:        }
                   1281:        /*
                   1282:         * Execute the command using the user's shell.  This uses the -c
                   1283:         * option to execute the command.
                   1284:         */
1.127     markus   1285:        argv[0] = (char *) shell0;
1.1       markus   1286:        argv[1] = "-c";
                   1287:        argv[2] = (char *) command;
                   1288:        argv[3] = NULL;
                   1289:        execve(shell, argv, env);
                   1290:        perror(shell);
                   1291:        exit(1);
                   1292: }
                   1293:
                   1294: Session *
                   1295: session_new(void)
                   1296: {
                   1297:        int i;
                   1298:        static int did_init = 0;
                   1299:        if (!did_init) {
                   1300:                debug("session_new: init");
1.112     deraadt  1301:                for (i = 0; i < MAX_SESSIONS; i++) {
1.1       markus   1302:                        sessions[i].used = 0;
                   1303:                }
                   1304:                did_init = 1;
                   1305:        }
1.112     deraadt  1306:        for (i = 0; i < MAX_SESSIONS; i++) {
1.1       markus   1307:                Session *s = &sessions[i];
                   1308:                if (! s->used) {
1.68      djm      1309:                        memset(s, 0, sizeof(*s));
1.1       markus   1310:                        s->chanid = -1;
                   1311:                        s->ptyfd = -1;
                   1312:                        s->ttyfd = -1;
                   1313:                        s->used = 1;
1.85      markus   1314:                        s->self = i;
1.184     djm      1315:                        s->x11_chanids = NULL;
1.1       markus   1316:                        debug("session_new: session %d", i);
                   1317:                        return s;
                   1318:                }
                   1319:        }
                   1320:        return NULL;
                   1321: }
                   1322:
1.94      itojun   1323: static void
1.1       markus   1324: session_dump(void)
                   1325: {
                   1326:        int i;
1.112     deraadt  1327:        for (i = 0; i < MAX_SESSIONS; i++) {
1.1       markus   1328:                Session *s = &sessions[i];
1.137     mpech    1329:                debug("dump: used %d session %d %p channel %d pid %ld",
1.1       markus   1330:                    s->used,
                   1331:                    s->self,
                   1332:                    s,
                   1333:                    s->chanid,
1.137     mpech    1334:                    (long)s->pid);
1.1       markus   1335:        }
                   1336: }
                   1337:
1.2       markus   1338: int
1.97      markus   1339: session_open(Authctxt *authctxt, int chanid)
1.2       markus   1340: {
                   1341:        Session *s = session_new();
                   1342:        debug("session_open: channel %d", chanid);
                   1343:        if (s == NULL) {
                   1344:                error("no more sessions");
                   1345:                return 0;
                   1346:        }
1.97      markus   1347:        s->authctxt = authctxt;
                   1348:        s->pw = authctxt->pw;
1.167     djm      1349:        if (s->pw == NULL || !authctxt->valid)
1.54      stevesk  1350:                fatal("no user for session %d", s->self);
1.2       markus   1351:        debug("session_open: session %d: link with channel %d", s->self, chanid);
                   1352:        s->chanid = chanid;
                   1353:        return 1;
                   1354: }
                   1355:
1.130     provos   1356: Session *
                   1357: session_by_tty(char *tty)
                   1358: {
                   1359:        int i;
                   1360:        for (i = 0; i < MAX_SESSIONS; i++) {
                   1361:                Session *s = &sessions[i];
                   1362:                if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
                   1363:                        debug("session_by_tty: session %d tty %s", i, tty);
                   1364:                        return s;
                   1365:                }
                   1366:        }
                   1367:        debug("session_by_tty: unknown tty %.100s", tty);
                   1368:        session_dump();
                   1369:        return NULL;
                   1370: }
                   1371:
1.94      itojun   1372: static Session *
1.2       markus   1373: session_by_channel(int id)
                   1374: {
                   1375:        int i;
1.112     deraadt  1376:        for (i = 0; i < MAX_SESSIONS; i++) {
1.2       markus   1377:                Session *s = &sessions[i];
                   1378:                if (s->used && s->chanid == id) {
                   1379:                        debug("session_by_channel: session %d channel %d", i, id);
                   1380:                        return s;
                   1381:                }
                   1382:        }
                   1383:        debug("session_by_channel: unknown channel %d", id);
                   1384:        session_dump();
                   1385:        return NULL;
                   1386: }
                   1387:
1.94      itojun   1388: static Session *
1.184     djm      1389: session_by_x11_channel(int id)
                   1390: {
                   1391:        int i, j;
                   1392:
                   1393:        for (i = 0; i < MAX_SESSIONS; i++) {
                   1394:                Session *s = &sessions[i];
                   1395:
                   1396:                if (s->x11_chanids == NULL || !s->used)
                   1397:                        continue;
                   1398:                for (j = 0; s->x11_chanids[j] != -1; j++) {
                   1399:                        if (s->x11_chanids[j] == id) {
                   1400:                                debug("session_by_x11_channel: session %d "
                   1401:                                    "channel %d", s->self, id);
                   1402:                                return s;
                   1403:                        }
                   1404:                }
                   1405:        }
                   1406:        debug("session_by_x11_channel: unknown channel %d", id);
                   1407:        session_dump();
                   1408:        return NULL;
                   1409: }
                   1410:
                   1411: static Session *
1.2       markus   1412: session_by_pid(pid_t pid)
                   1413: {
                   1414:        int i;
1.137     mpech    1415:        debug("session_by_pid: pid %ld", (long)pid);
1.112     deraadt  1416:        for (i = 0; i < MAX_SESSIONS; i++) {
1.2       markus   1417:                Session *s = &sessions[i];
                   1418:                if (s->used && s->pid == pid)
                   1419:                        return s;
                   1420:        }
1.137     mpech    1421:        error("session_by_pid: unknown pid %ld", (long)pid);
1.2       markus   1422:        session_dump();
                   1423:        return NULL;
                   1424: }
                   1425:
1.94      itojun   1426: static int
1.2       markus   1427: session_window_change_req(Session *s)
                   1428: {
                   1429:        s->col = packet_get_int();
                   1430:        s->row = packet_get_int();
                   1431:        s->xpixel = packet_get_int();
                   1432:        s->ypixel = packet_get_int();
1.116     markus   1433:        packet_check_eom();
1.2       markus   1434:        pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
                   1435:        return 1;
                   1436: }
                   1437:
1.94      itojun   1438: static int
1.2       markus   1439: session_pty_req(Session *s)
                   1440: {
1.45      markus   1441:        u_int len;
1.72      stevesk  1442:        int n_bytes;
1.132     markus   1443:
1.86      markus   1444:        if (no_pty_flag) {
                   1445:                debug("Allocating a pty not permitted for this authentication.");
1.19      markus   1446:                return 0;
1.86      markus   1447:        }
                   1448:        if (s->ttyfd != -1) {
                   1449:                packet_disconnect("Protocol error: you already have a pty.");
1.3       markus   1450:                return 0;
1.86      markus   1451:        }
                   1452:
1.2       markus   1453:        s->term = packet_get_string(&len);
1.86      markus   1454:
                   1455:        if (compat20) {
                   1456:                s->col = packet_get_int();
                   1457:                s->row = packet_get_int();
                   1458:        } else {
                   1459:                s->row = packet_get_int();
                   1460:                s->col = packet_get_int();
                   1461:        }
1.2       markus   1462:        s->xpixel = packet_get_int();
                   1463:        s->ypixel = packet_get_int();
                   1464:
                   1465:        if (strcmp(s->term, "") == 0) {
                   1466:                xfree(s->term);
                   1467:                s->term = NULL;
                   1468:        }
1.86      markus   1469:
1.2       markus   1470:        /* Allocate a pty and open it. */
1.86      markus   1471:        debug("Allocating pty.");
1.130     provos   1472:        if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1.86      markus   1473:                if (s->term)
                   1474:                        xfree(s->term);
1.2       markus   1475:                s->term = NULL;
                   1476:                s->ptyfd = -1;
                   1477:                s->ttyfd = -1;
                   1478:                error("session_pty_req: session %d alloc failed", s->self);
1.3       markus   1479:                return 0;
1.2       markus   1480:        }
                   1481:        debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86      markus   1482:
                   1483:        /* for SSH1 the tty modes length is not given */
                   1484:        if (!compat20)
                   1485:                n_bytes = packet_remaining();
                   1486:        tty_parse_modes(s->ttyfd, &n_bytes);
                   1487:
1.130     provos   1488:        if (!use_privsep)
                   1489:                pty_setowner(s->pw, s->tty);
1.86      markus   1490:
                   1491:        /* Set window size from the packet. */
1.2       markus   1492:        pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
                   1493:
1.116     markus   1494:        packet_check_eom();
1.9       markus   1495:        session_proctitle(s);
1.2       markus   1496:        return 1;
                   1497: }
                   1498:
1.94      itojun   1499: static int
1.7       markus   1500: session_subsystem_req(Session *s)
                   1501: {
1.105     markus   1502:        struct stat st;
1.45      markus   1503:        u_int len;
1.7       markus   1504:        int success = 0;
1.205     djm      1505:        char *prog, *cmd, *subsys = packet_get_string(&len);
1.182     djm      1506:        u_int i;
1.7       markus   1507:
1.116     markus   1508:        packet_check_eom();
1.155     itojun   1509:        logit("subsystem request for %.100s", subsys);
1.18      jakob    1510:
                   1511:        for (i = 0; i < options.num_subsystems; i++) {
1.105     markus   1512:                if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1.205     djm      1513:                        prog = options.subsystem_command[i];
                   1514:                        cmd = options.subsystem_args[i];
1.226     djm      1515:                        if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
1.225     markus   1516:                                s->is_subsystem = SUBSYSTEM_INT_SFTP;
                   1517:                        } else if (stat(prog, &st) < 0) {
1.205     djm      1518:                                error("subsystem: cannot stat %s: %s", prog,
1.105     markus   1519:                                    strerror(errno));
                   1520:                                break;
1.225     markus   1521:                        } else {
                   1522:                                s->is_subsystem = SUBSYSTEM_EXT;
1.105     markus   1523:                        }
                   1524:                        debug("subsystem: exec() %s", cmd);
                   1525:                        do_exec(s, cmd);
1.18      jakob    1526:                        success = 1;
1.122     markus   1527:                        break;
1.18      jakob    1528:                }
                   1529:        }
                   1530:
                   1531:        if (!success)
1.155     itojun   1532:                logit("subsystem request for %.100s failed, subsystem not found",
1.105     markus   1533:                    subsys);
1.7       markus   1534:
                   1535:        xfree(subsys);
                   1536:        return success;
                   1537: }
                   1538:
1.94      itojun   1539: static int
1.7       markus   1540: session_x11_req(Session *s)
                   1541: {
1.81      markus   1542:        int success;
1.7       markus   1543:
1.184     djm      1544:        if (s->auth_proto != NULL || s->auth_data != NULL) {
                   1545:                error("session_x11_req: session %d: "
1.190     stevesk  1546:                    "x11 forwarding already active", s->self);
1.184     djm      1547:                return 0;
                   1548:        }
1.7       markus   1549:        s->single_connection = packet_get_char();
                   1550:        s->auth_proto = packet_get_string(NULL);
                   1551:        s->auth_data = packet_get_string(NULL);
                   1552:        s->screen = packet_get_int();
1.116     markus   1553:        packet_check_eom();
1.7       markus   1554:
1.81      markus   1555:        success = session_setup_x11fwd(s);
                   1556:        if (!success) {
1.7       markus   1557:                xfree(s->auth_proto);
                   1558:                xfree(s->auth_data);
1.84      markus   1559:                s->auth_proto = NULL;
                   1560:                s->auth_data = NULL;
1.7       markus   1561:        }
1.81      markus   1562:        return success;
1.7       markus   1563: }
                   1564:
1.94      itojun   1565: static int
1.19      markus   1566: session_shell_req(Session *s)
                   1567: {
1.116     markus   1568:        packet_check_eom();
1.90      markus   1569:        do_exec(s, NULL);
1.19      markus   1570:        return 1;
                   1571: }
                   1572:
1.94      itojun   1573: static int
1.19      markus   1574: session_exec_req(Session *s)
                   1575: {
1.45      markus   1576:        u_int len;
1.19      markus   1577:        char *command = packet_get_string(&len);
1.116     markus   1578:        packet_check_eom();
1.90      markus   1579:        do_exec(s, command);
1.92      markus   1580:        xfree(command);
1.19      markus   1581:        return 1;
                   1582: }
                   1583:
1.94      itojun   1584: static int
1.157     markus   1585: session_break_req(Session *s)
                   1586: {
                   1587:
1.175     deraadt  1588:        packet_get_int();       /* ignored */
1.157     markus   1589:        packet_check_eom();
                   1590:
1.160     markus   1591:        if (s->ttyfd == -1 ||
                   1592:            tcsendbreak(s->ttyfd, 0) < 0)
1.157     markus   1593:                return 0;
                   1594:        return 1;
                   1595: }
                   1596:
                   1597: static int
1.173     djm      1598: session_env_req(Session *s)
                   1599: {
                   1600:        char *name, *val;
                   1601:        u_int name_len, val_len, i;
                   1602:
                   1603:        name = packet_get_string(&name_len);
                   1604:        val = packet_get_string(&val_len);
                   1605:        packet_check_eom();
                   1606:
                   1607:        /* Don't set too many environment variables */
                   1608:        if (s->num_env > 128) {
                   1609:                debug2("Ignoring env request %s: too many env vars", name);
                   1610:                goto fail;
                   1611:        }
                   1612:
                   1613:        for (i = 0; i < options.num_accept_env; i++) {
                   1614:                if (match_pattern(name, options.accept_env[i])) {
                   1615:                        debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.201     djm      1616:                        s->env = xrealloc(s->env, s->num_env + 1,
                   1617:                            sizeof(*s->env));
1.173     djm      1618:                        s->env[s->num_env].name = name;
                   1619:                        s->env[s->num_env].val = val;
                   1620:                        s->num_env++;
                   1621:                        return (1);
                   1622:                }
                   1623:        }
                   1624:        debug2("Ignoring env request %s: disallowed name", name);
                   1625:
                   1626:  fail:
                   1627:        xfree(name);
                   1628:        xfree(val);
                   1629:        return (0);
                   1630: }
                   1631:
                   1632: static int
1.43      markus   1633: session_auth_agent_req(Session *s)
                   1634: {
                   1635:        static int called = 0;
1.116     markus   1636:        packet_check_eom();
1.44      markus   1637:        if (no_agent_forwarding_flag) {
                   1638:                debug("session_auth_agent_req: no_agent_forwarding_flag");
                   1639:                return 0;
                   1640:        }
1.43      markus   1641:        if (called) {
                   1642:                return 0;
                   1643:        } else {
                   1644:                called = 1;
                   1645:                return auth_input_request_forwarding(s->pw);
                   1646:        }
                   1647: }
                   1648:
1.123     markus   1649: int
                   1650: session_input_channel_req(Channel *c, const char *rtype)
1.2       markus   1651: {
                   1652:        int success = 0;
                   1653:        Session *s;
                   1654:
1.123     markus   1655:        if ((s = session_by_channel(c->self)) == NULL) {
1.155     itojun   1656:                logit("session_input_channel_req: no session %d req %.100s",
1.123     markus   1657:                    c->self, rtype);
                   1658:                return 0;
                   1659:        }
                   1660:        debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2       markus   1661:
                   1662:        /*
1.64      markus   1663:         * a session is in LARVAL state until a shell, a command
                   1664:         * or a subsystem is executed
1.2       markus   1665:         */
                   1666:        if (c->type == SSH_CHANNEL_LARVAL) {
                   1667:                if (strcmp(rtype, "shell") == 0) {
1.19      markus   1668:                        success = session_shell_req(s);
1.2       markus   1669:                } else if (strcmp(rtype, "exec") == 0) {
1.19      markus   1670:                        success = session_exec_req(s);
1.2       markus   1671:                } else if (strcmp(rtype, "pty-req") == 0) {
1.221     stevesk  1672:                        success = session_pty_req(s);
1.7       markus   1673:                } else if (strcmp(rtype, "x11-req") == 0) {
                   1674:                        success = session_x11_req(s);
1.43      markus   1675:                } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
                   1676:                        success = session_auth_agent_req(s);
1.7       markus   1677:                } else if (strcmp(rtype, "subsystem") == 0) {
                   1678:                        success = session_subsystem_req(s);
1.173     djm      1679:                } else if (strcmp(rtype, "env") == 0) {
                   1680:                        success = session_env_req(s);
1.2       markus   1681:                }
                   1682:        }
                   1683:        if (strcmp(rtype, "window-change") == 0) {
                   1684:                success = session_window_change_req(s);
1.177     djm      1685:        } else if (strcmp(rtype, "break") == 0) {
                   1686:                success = session_break_req(s);
1.2       markus   1687:        }
1.177     djm      1688:
1.123     markus   1689:        return success;
1.2       markus   1690: }
                   1691:
                   1692: void
                   1693: session_set_fds(Session *s, int fdin, int fdout, int fderr)
                   1694: {
                   1695:        if (!compat20)
                   1696:                fatal("session_set_fds: called for proto != 2.0");
                   1697:        /*
                   1698:         * now that have a child and a pipe to the child,
                   1699:         * we can activate our channel and register the fd's
                   1700:         */
                   1701:        if (s->chanid == -1)
                   1702:                fatal("no channel for session %d", s->self);
                   1703:        channel_set_fds(s->chanid,
                   1704:            fdout, fdin, fderr,
1.42      markus   1705:            fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.126     markus   1706:            1,
                   1707:            CHAN_SES_WINDOW_DEFAULT);
1.2       markus   1708: }
                   1709:
1.85      markus   1710: /*
                   1711:  * Function to perform pty cleanup. Also called if we get aborted abnormally
                   1712:  * (e.g., due to a dropped connection).
                   1713:  */
1.130     provos   1714: void
1.165     markus   1715: session_pty_cleanup2(Session *s)
1.1       markus   1716: {
1.85      markus   1717:        if (s == NULL) {
                   1718:                error("session_pty_cleanup: no session");
                   1719:                return;
                   1720:        }
                   1721:        if (s->ttyfd == -1)
1.1       markus   1722:                return;
                   1723:
1.54      stevesk  1724:        debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1       markus   1725:
                   1726:        /* Record that the user has logged out. */
1.85      markus   1727:        if (s->pid != 0)
                   1728:                record_logout(s->pid, s->tty);
1.1       markus   1729:
                   1730:        /* Release the pseudo-tty. */
1.130     provos   1731:        if (getuid() == 0)
                   1732:                pty_release(s->tty);
1.1       markus   1733:
                   1734:        /*
                   1735:         * Close the server side of the socket pairs.  We must do this after
                   1736:         * the pty cleanup, so that another process doesn't get this pty
                   1737:         * while we're still cleaning up.
                   1738:         */
                   1739:        if (close(s->ptymaster) < 0)
1.130     provos   1740:                error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1.108     markus   1741:
                   1742:        /* unlink pty from session */
                   1743:        s->ttyfd = -1;
1.2       markus   1744: }
                   1745:
1.130     provos   1746: void
1.165     markus   1747: session_pty_cleanup(Session *s)
1.130     provos   1748: {
1.165     markus   1749:        PRIVSEP(session_pty_cleanup2(s));
1.130     provos   1750: }
                   1751:
1.147     markus   1752: static char *
                   1753: sig2name(int sig)
                   1754: {
                   1755: #define SSH_SIG(x) if (sig == SIG ## x) return #x
                   1756:        SSH_SIG(ABRT);
                   1757:        SSH_SIG(ALRM);
                   1758:        SSH_SIG(FPE);
                   1759:        SSH_SIG(HUP);
                   1760:        SSH_SIG(ILL);
                   1761:        SSH_SIG(INT);
                   1762:        SSH_SIG(KILL);
                   1763:        SSH_SIG(PIPE);
                   1764:        SSH_SIG(QUIT);
                   1765:        SSH_SIG(SEGV);
                   1766:        SSH_SIG(TERM);
                   1767:        SSH_SIG(USR1);
                   1768:        SSH_SIG(USR2);
                   1769: #undef SSH_SIG
                   1770:        return "SIG@openssh.com";
                   1771: }
                   1772:
1.94      itojun   1773: static void
1.184     djm      1774: session_close_x11(int id)
                   1775: {
                   1776:        Channel *c;
                   1777:
1.189     markus   1778:        if ((c = channel_by_id(id)) == NULL) {
1.184     djm      1779:                debug("session_close_x11: x11 channel %d missing", id);
                   1780:        } else {
                   1781:                /* Detach X11 listener */
                   1782:                debug("session_close_x11: detach x11 channel %d", id);
                   1783:                channel_cancel_cleanup(id);
                   1784:                if (c->ostate != CHAN_OUTPUT_CLOSED)
                   1785:                        chan_mark_dead(c);
                   1786:        }
                   1787: }
                   1788:
                   1789: static void
                   1790: session_close_single_x11(int id, void *arg)
                   1791: {
                   1792:        Session *s;
                   1793:        u_int i;
                   1794:
                   1795:        debug3("session_close_single_x11: channel %d", id);
                   1796:        channel_cancel_cleanup(id);
1.221     stevesk  1797:        if ((s = session_by_x11_channel(id)) == NULL)
1.184     djm      1798:                fatal("session_close_single_x11: no x11 channel %d", id);
                   1799:        for (i = 0; s->x11_chanids[i] != -1; i++) {
                   1800:                debug("session_close_single_x11: session %d: "
                   1801:                    "closing channel %d", s->self, s->x11_chanids[i]);
                   1802:                /*
                   1803:                 * The channel "id" is already closing, but make sure we
                   1804:                 * close all of its siblings.
                   1805:                 */
                   1806:                if (s->x11_chanids[i] != id)
                   1807:                        session_close_x11(s->x11_chanids[i]);
                   1808:        }
                   1809:        xfree(s->x11_chanids);
                   1810:        s->x11_chanids = NULL;
                   1811:        if (s->display) {
                   1812:                xfree(s->display);
                   1813:                s->display = NULL;
                   1814:        }
                   1815:        if (s->auth_proto) {
                   1816:                xfree(s->auth_proto);
                   1817:                s->auth_proto = NULL;
                   1818:        }
                   1819:        if (s->auth_data) {
                   1820:                xfree(s->auth_data);
                   1821:                s->auth_data = NULL;
                   1822:        }
                   1823:        if (s->auth_display) {
                   1824:                xfree(s->auth_display);
                   1825:                s->auth_display = NULL;
                   1826:        }
                   1827: }
                   1828:
                   1829: static void
1.2       markus   1830: session_exit_message(Session *s, int status)
                   1831: {
                   1832:        Channel *c;
1.124     markus   1833:
                   1834:        if ((c = channel_lookup(s->chanid)) == NULL)
1.85      markus   1835:                fatal("session_exit_message: session %d: no channel %d",
1.2       markus   1836:                    s->self, s->chanid);
1.137     mpech    1837:        debug("session_exit_message: session %d channel %d pid %ld",
                   1838:            s->self, s->chanid, (long)s->pid);
1.2       markus   1839:
                   1840:        if (WIFEXITED(status)) {
1.124     markus   1841:                channel_request_start(s->chanid, "exit-status", 0);
1.2       markus   1842:                packet_put_int(WEXITSTATUS(status));
                   1843:                packet_send();
                   1844:        } else if (WIFSIGNALED(status)) {
1.124     markus   1845:                channel_request_start(s->chanid, "exit-signal", 0);
1.147     markus   1846:                packet_put_cstring(sig2name(WTERMSIG(status)));
1.229     markus   1847:                packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2       markus   1848:                packet_put_cstring("");
                   1849:                packet_put_cstring("");
                   1850:                packet_send();
                   1851:        } else {
                   1852:                /* Some weird exit cause.  Just exit. */
                   1853:                packet_disconnect("wait returned status %04x.", status);
                   1854:        }
                   1855:
                   1856:        /* disconnect channel */
                   1857:        debug("session_exit_message: release channel %d", s->chanid);
1.187     djm      1858:
                   1859:        /*
                   1860:         * Adjust cleanup callback attachment to send close messages when
1.199     deraadt  1861:         * the channel gets EOF. The session will be then be closed
1.187     djm      1862:         * by session_close_by_channel when the childs close their fds.
                   1863:         */
                   1864:        channel_register_cleanup(c->self, session_close_by_channel, 1);
                   1865:
1.5       markus   1866:        /*
                   1867:         * emulate a write failure with 'chan_write_failed', nobody will be
                   1868:         * interested in data we write.
                   1869:         * Note that we must not call 'chan_read_failed', since there could
                   1870:         * be some more data waiting in the pipe.
                   1871:         */
1.8       markus   1872:        if (c->ostate != CHAN_OUTPUT_CLOSED)
                   1873:                chan_write_failed(c);
1.2       markus   1874: }
                   1875:
1.130     provos   1876: void
1.85      markus   1877: session_close(Session *s)
1.2       markus   1878: {
1.182     djm      1879:        u_int i;
1.173     djm      1880:
1.137     mpech    1881:        debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165     markus   1882:        if (s->ttyfd != -1)
1.85      markus   1883:                session_pty_cleanup(s);
1.2       markus   1884:        if (s->term)
                   1885:                xfree(s->term);
                   1886:        if (s->display)
                   1887:                xfree(s->display);
1.184     djm      1888:        if (s->x11_chanids)
                   1889:                xfree(s->x11_chanids);
1.118     stevesk  1890:        if (s->auth_display)
                   1891:                xfree(s->auth_display);
1.2       markus   1892:        if (s->auth_data)
                   1893:                xfree(s->auth_data);
                   1894:        if (s->auth_proto)
                   1895:                xfree(s->auth_proto);
                   1896:        s->used = 0;
1.219     djm      1897:        if (s->env != NULL) {
                   1898:                for (i = 0; i < s->num_env; i++) {
                   1899:                        xfree(s->env[i].name);
                   1900:                        xfree(s->env[i].val);
                   1901:                }
                   1902:                xfree(s->env);
1.173     djm      1903:        }
1.9       markus   1904:        session_proctitle(s);
1.2       markus   1905: }
                   1906:
                   1907: void
                   1908: session_close_by_pid(pid_t pid, int status)
                   1909: {
                   1910:        Session *s = session_by_pid(pid);
                   1911:        if (s == NULL) {
1.137     mpech    1912:                debug("session_close_by_pid: no session for pid %ld",
                   1913:                    (long)pid);
1.2       markus   1914:                return;
                   1915:        }
                   1916:        if (s->chanid != -1)
                   1917:                session_exit_message(s, status);
1.187     djm      1918:        if (s->ttyfd != -1)
                   1919:                session_pty_cleanup(s);
1.197     djm      1920:        s->pid = 0;
1.98      markus   1921: }
                   1922:
1.2       markus   1923: /*
                   1924:  * this is called when a channel dies before
                   1925:  * the session 'child' itself dies
                   1926:  */
                   1927: void
                   1928: session_close_by_channel(int id, void *arg)
                   1929: {
                   1930:        Session *s = session_by_channel(id);
1.187     djm      1931:        u_int i;
1.184     djm      1932:
1.2       markus   1933:        if (s == NULL) {
1.107     markus   1934:                debug("session_close_by_channel: no session for id %d", id);
1.2       markus   1935:                return;
                   1936:        }
1.137     mpech    1937:        debug("session_close_by_channel: channel %d child %ld",
                   1938:            id, (long)s->pid);
1.107     markus   1939:        if (s->pid != 0) {
                   1940:                debug("session_close_by_channel: channel %d: has child", id);
1.108     markus   1941:                /*
                   1942:                 * delay detach of session, but release pty, since
                   1943:                 * the fd's to the child are already closed
                   1944:                 */
1.165     markus   1945:                if (s->ttyfd != -1)
1.108     markus   1946:                        session_pty_cleanup(s);
1.107     markus   1947:                return;
                   1948:        }
                   1949:        /* detach by removing callback */
1.2       markus   1950:        channel_cancel_cleanup(s->chanid);
1.187     djm      1951:
                   1952:        /* Close any X11 listeners associated with this session */
                   1953:        if (s->x11_chanids != NULL) {
                   1954:                for (i = 0; s->x11_chanids[i] != -1; i++) {
                   1955:                        session_close_x11(s->x11_chanids[i]);
                   1956:                        s->x11_chanids[i] = -1;
                   1957:                }
                   1958:        }
                   1959:
1.2       markus   1960:        s->chanid = -1;
1.106     markus   1961:        session_close(s);
                   1962: }
                   1963:
                   1964: void
1.130     provos   1965: session_destroy_all(void (*closefunc)(Session *))
1.106     markus   1966: {
                   1967:        int i;
1.112     deraadt  1968:        for (i = 0; i < MAX_SESSIONS; i++) {
1.106     markus   1969:                Session *s = &sessions[i];
1.130     provos   1970:                if (s->used) {
                   1971:                        if (closefunc != NULL)
                   1972:                                closefunc(s);
                   1973:                        else
                   1974:                                session_close(s);
                   1975:                }
1.2       markus   1976:        }
1.9       markus   1977: }
                   1978:
1.94      itojun   1979: static char *
1.9       markus   1980: session_tty_list(void)
                   1981: {
                   1982:        static char buf[1024];
                   1983:        int i;
                   1984:        buf[0] = '\0';
1.112     deraadt  1985:        for (i = 0; i < MAX_SESSIONS; i++) {
1.9       markus   1986:                Session *s = &sessions[i];
                   1987:                if (s->used && s->ttyfd != -1) {
                   1988:                        if (buf[0] != '\0')
                   1989:                                strlcat(buf, ",", sizeof buf);
                   1990:                        strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
                   1991:                }
                   1992:        }
                   1993:        if (buf[0] == '\0')
                   1994:                strlcpy(buf, "notty", sizeof buf);
                   1995:        return buf;
                   1996: }
                   1997:
                   1998: void
                   1999: session_proctitle(Session *s)
                   2000: {
                   2001:        if (s->pw == NULL)
                   2002:                error("no user for session %d", s->self);
                   2003:        else
                   2004:                setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81      markus   2005: }
                   2006:
                   2007: int
                   2008: session_setup_x11fwd(Session *s)
                   2009: {
                   2010:        struct stat st;
1.109     stevesk  2011:        char display[512], auth_display[512];
                   2012:        char hostname[MAXHOSTNAMELEN];
1.184     djm      2013:        u_int i;
1.81      markus   2014:
                   2015:        if (no_x11_forwarding_flag) {
                   2016:                packet_send_debug("X11 forwarding disabled in user configuration file.");
                   2017:                return 0;
                   2018:        }
                   2019:        if (!options.x11_forwarding) {
                   2020:                debug("X11 forwarding disabled in server configuration file.");
                   2021:                return 0;
                   2022:        }
                   2023:        if (!options.xauth_location ||
                   2024:            (stat(options.xauth_location, &st) == -1)) {
                   2025:                packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91      markus   2026:                return 0;
                   2027:        }
                   2028:        if (options.use_login) {
                   2029:                packet_send_debug("X11 forwarding disabled; "
                   2030:                    "not compatible with UseLogin=yes.");
1.81      markus   2031:                return 0;
                   2032:        }
1.87      markus   2033:        if (s->display != NULL) {
1.81      markus   2034:                debug("X11 display already set.");
                   2035:                return 0;
                   2036:        }
1.140     deraadt  2037:        if (x11_create_display_inet(options.x11_display_offset,
                   2038:            options.x11_use_localhost, s->single_connection,
1.184     djm      2039:            &s->display_number, &s->x11_chanids) == -1) {
1.87      markus   2040:                debug("x11_create_display_inet failed.");
1.81      markus   2041:                return 0;
1.184     djm      2042:        }
                   2043:        for (i = 0; s->x11_chanids[i] != -1; i++) {
                   2044:                channel_register_cleanup(s->x11_chanids[i],
1.187     djm      2045:                    session_close_single_x11, 0);
1.81      markus   2046:        }
1.109     stevesk  2047:
                   2048:        /* Set up a suitable value for the DISPLAY variable. */
                   2049:        if (gethostname(hostname, sizeof(hostname)) < 0)
                   2050:                fatal("gethostname: %.100s", strerror(errno));
                   2051:        /*
                   2052:         * auth_display must be used as the displayname when the
                   2053:         * authorization entry is added with xauth(1).  This will be
                   2054:         * different than the DISPLAY string for localhost displays.
                   2055:         */
1.119     stevesk  2056:        if (options.x11_use_localhost) {
1.140     deraadt  2057:                snprintf(display, sizeof display, "localhost:%u.%u",
1.109     stevesk  2058:                    s->display_number, s->screen);
1.140     deraadt  2059:                snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118     stevesk  2060:                    s->display_number, s->screen);
1.109     stevesk  2061:                s->display = xstrdup(display);
1.118     stevesk  2062:                s->auth_display = xstrdup(auth_display);
1.109     stevesk  2063:        } else {
1.140     deraadt  2064:                snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109     stevesk  2065:                    s->display_number, s->screen);
                   2066:                s->display = xstrdup(display);
1.118     stevesk  2067:                s->auth_display = xstrdup(display);
1.109     stevesk  2068:        }
                   2069:
1.81      markus   2070:        return 1;
1.2       markus   2071: }
                   2072:
1.94      itojun   2073: static void
1.49      markus   2074: do_authenticated2(Authctxt *authctxt)
1.2       markus   2075: {
1.97      markus   2076:        server_loop2(authctxt);
1.165     markus   2077: }
                   2078:
                   2079: void
                   2080: do_cleanup(Authctxt *authctxt)
                   2081: {
                   2082:        static int called = 0;
                   2083:
                   2084:        debug("do_cleanup");
                   2085:
                   2086:        /* no cleanup if we're in the child for login shell */
                   2087:        if (is_child)
                   2088:                return;
                   2089:
                   2090:        /* avoid double cleanup */
                   2091:        if (called)
                   2092:                return;
                   2093:        called = 1;
                   2094:
1.218     markus   2095:        if (authctxt == NULL || !authctxt->authenticated)
1.165     markus   2096:                return;
                   2097: #ifdef KRB5
                   2098:        if (options.kerberos_ticket_cleanup &&
                   2099:            authctxt->krb5_ctx)
                   2100:                krb5_cleanup_proc(authctxt);
1.161     markus   2101: #endif
1.165     markus   2102:
                   2103: #ifdef GSSAPI
                   2104:        if (compat20 && options.gss_cleanup_creds)
                   2105:                ssh_gssapi_cleanup_creds();
                   2106: #endif
                   2107:
                   2108:        /* remove agent socket */
                   2109:        auth_sock_cleanup_proc(authctxt->pw);
                   2110:
                   2111:        /*
                   2112:         * Cleanup ptys/utmp only if privsep is disabled,
                   2113:         * or if running in monitor.
                   2114:         */
                   2115:        if (!use_privsep || mm_is_monitor())
                   2116:                session_destroy_all(session_pty_cleanup2);
1.1       markus   2117: }