Annotation of src/usr.bin/ssh/session.c, Revision 1.87
1.1 markus 1: /*
2: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
3: * All rights reserved
1.37 deraadt 4: *
5: * As far as I am concerned, the code I have written for this software
6: * can be used freely for any purpose. Any derived versions of this
7: * software must be clearly marked as such, and if the derived work is
8: * incompatible with the protocol description in the RFC file, it must be
9: * called by a name other than "ssh" or "Secure Shell".
10: *
1.2 markus 11: * SSH2 support by Markus Friedl.
1.58 deraadt 12: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.37 deraadt 13: *
14: * Redistribution and use in source and binary forms, with or without
15: * modification, are permitted provided that the following conditions
16: * are met:
17: * 1. Redistributions of source code must retain the above copyright
18: * notice, this list of conditions and the following disclaimer.
19: * 2. Redistributions in binary form must reproduce the above copyright
20: * notice, this list of conditions and the following disclaimer in the
21: * documentation and/or other materials provided with the distribution.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.2 markus 33: */
1.1 markus 34:
35: #include "includes.h"
1.87 ! markus 36: RCSID("$OpenBSD: session.c,v 1.86 2001/06/12 16:10:38 markus Exp $");
1.1 markus 37:
1.51 markus 38: #include "ssh.h"
39: #include "ssh1.h"
40: #include "ssh2.h"
1.1 markus 41: #include "xmalloc.h"
1.59 djm 42: #include "sshpty.h"
1.1 markus 43: #include "packet.h"
44: #include "buffer.h"
45: #include "mpaux.h"
46: #include "uidswap.h"
47: #include "compat.h"
1.78 markus 48: #include "channels.h"
1.2 markus 49: #include "bufaux.h"
50: #include "auth.h"
1.19 markus 51: #include "auth-options.h"
1.50 markus 52: #include "pathnames.h"
1.51 markus 53: #include "log.h"
54: #include "servconf.h"
1.59 djm 55: #include "sshlogin.h"
1.51 markus 56: #include "serverloop.h"
57: #include "canohost.h"
1.55 itojun 58: #include "session.h"
1.2 markus 59:
1.1 markus 60: /* types */
61:
62: #define TTYSZ 64
63: typedef struct Session Session;
64: struct Session {
65: int used;
66: int self;
67: struct passwd *pw;
68: pid_t pid;
69: /* tty */
70: char *term;
71: int ptyfd, ttyfd, ptymaster;
72: int row, col, xpixel, ypixel;
73: char tty[TTYSZ];
74: /* X11 */
75: char *display;
76: int screen;
77: char *auth_proto;
78: char *auth_data;
1.7 markus 79: int single_connection;
1.1 markus 80: /* proto 2 */
81: int chanid;
1.64 markus 82: int is_subsystem;
1.1 markus 83: };
84:
85: /* func */
86:
87: Session *session_new(void);
88: void session_set_fds(Session *s, int fdin, int fdout, int fderr);
1.85 markus 89: void session_pty_cleanup(void *session);
1.86 markus 90: int session_pty_req(Session *s);
1.9 markus 91: void session_proctitle(Session *s);
1.81 markus 92: int session_setup_x11fwd(Session *s);
1.82 markus 93: void session_close(Session *s);
1.63 markus 94: void do_exec_pty(Session *s, const char *command);
95: void do_exec_no_pty(Session *s, const char *command);
1.41 markus 96: void do_login(Session *s, const char *command);
1.60 markus 97: void do_child(Session *s, const char *command);
1.73 djm 98: void do_motd(void);
99: int check_quietlogin(Session *s, const char *command);
1.1 markus 100:
1.65 markus 101: void do_authenticated1(Authctxt *authctxt);
102: void do_authenticated2(Authctxt *authctxt);
103:
1.1 markus 104: /* import */
105: extern ServerOptions options;
106: extern char *__progname;
107: extern int log_stderr;
108: extern int debug_flag;
1.45 markus 109: extern u_int utmp_len;
1.21 markus 110: extern int startup_pipe;
1.74 markus 111: extern void destroy_sensitive_data(void);
1.21 markus 112:
1.34 markus 113: /* original command from peer. */
1.53 stevesk 114: char *original_command = NULL;
1.34 markus 115:
1.1 markus 116: /* data */
117: #define MAX_SESSIONS 10
118: Session sessions[MAX_SESSIONS];
119:
1.28 millert 120: #ifdef HAVE_LOGIN_CAP
121: static login_cap_t *lc;
122: #endif
123:
1.65 markus 124: void
125: do_authenticated(Authctxt *authctxt)
126: {
127: /*
128: * Cancel the alarm we set to limit the time taken for
129: * authentication.
130: */
131: alarm(0);
132: if (startup_pipe != -1) {
133: close(startup_pipe);
134: startup_pipe = -1;
135: }
136: #ifdef HAVE_LOGIN_CAP
137: if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
138: error("unable to get login class");
139: return;
140: }
1.74 markus 141: #ifdef BSD_AUTH
142: if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
143: packet_disconnect("Approval failure for %s",
144: authctxt->pw->pw_name);
145: }
146: #endif
1.65 markus 147: #endif
148: /* setup the channel layer */
149: if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
150: channel_permit_all_opens();
151:
152: if (compat20)
153: do_authenticated2(authctxt);
154: else
155: do_authenticated1(authctxt);
1.79 markus 156:
1.87 ! markus 157: /* remove agent socket */
1.79 markus 158: if (auth_get_socket_name())
1.80 markus 159: auth_sock_cleanup_proc(authctxt->pw);
1.65 markus 160: }
161:
1.1 markus 162: /*
163: * Prepares for an interactive session. This is called after the user has
164: * been successfully authenticated. During this message exchange, pseudo
165: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
166: * are requested, etc.
167: */
1.4 markus 168: void
1.65 markus 169: do_authenticated1(Authctxt *authctxt)
1.1 markus 170: {
171: Session *s;
1.65 markus 172: char *command;
1.86 markus 173: int success, type, plen, screen_flag;
1.1 markus 174: int compression_level = 0, enable_compression_after_reply = 0;
1.45 markus 175: u_int proto_len, data_len, dlen;
1.1 markus 176:
1.61 markus 177: s = session_new();
1.65 markus 178: s->pw = authctxt->pw;
1.28 millert 179:
1.1 markus 180: /*
181: * We stay in this loop until the client requests to execute a shell
182: * or a command.
183: */
184: for (;;) {
1.65 markus 185: success = 0;
1.1 markus 186:
187: /* Get a packet from the client. */
188: type = packet_read(&plen);
189:
190: /* Process the packet. */
191: switch (type) {
192: case SSH_CMSG_REQUEST_COMPRESSION:
193: packet_integrity_check(plen, 4, type);
194: compression_level = packet_get_int();
195: if (compression_level < 1 || compression_level > 9) {
196: packet_send_debug("Received illegal compression level %d.",
197: compression_level);
198: break;
199: }
200: /* Enable compression after we have responded with SUCCESS. */
201: enable_compression_after_reply = 1;
202: success = 1;
203: break;
204:
205: case SSH_CMSG_REQUEST_PTY:
1.86 markus 206: success = session_pty_req(s);
1.1 markus 207: break;
208:
209: case SSH_CMSG_X11_REQUEST_FORWARDING:
210: s->auth_proto = packet_get_string(&proto_len);
211: s->auth_data = packet_get_string(&data_len);
212:
1.57 markus 213: screen_flag = packet_get_protocol_flags() &
214: SSH_PROTOFLAG_SCREEN_NUMBER;
215: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
216:
217: if (packet_remaining() == 4) {
218: if (!screen_flag)
219: debug2("Buggy client: "
220: "X11 screen flag missing");
1.1 markus 221: s->screen = packet_get_int();
1.56 markus 222: } else {
1.1 markus 223: s->screen = 0;
1.56 markus 224: }
1.81 markus 225: packet_done();
226: success = session_setup_x11fwd(s);
227: if (!success) {
228: xfree(s->auth_proto);
229: xfree(s->auth_data);
1.84 markus 230: s->auth_proto = NULL;
231: s->auth_data = NULL;
1.1 markus 232: }
233: break;
234:
235: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
236: if (no_agent_forwarding_flag || compat13) {
237: debug("Authentication agent forwarding not permitted for this authentication.");
238: break;
239: }
240: debug("Received authentication agent forwarding request.");
1.65 markus 241: success = auth_input_request_forwarding(s->pw);
1.1 markus 242: break;
243:
244: case SSH_CMSG_PORT_FORWARD_REQUEST:
245: if (no_port_forwarding_flag) {
246: debug("Port forwarding not permitted for this authentication.");
1.39 markus 247: break;
248: }
249: if (!options.allow_tcp_forwarding) {
250: debug("Port forwarding not permitted.");
1.1 markus 251: break;
252: }
253: debug("Received TCP/IP port forwarding request.");
1.65 markus 254: channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
1.1 markus 255: success = 1;
256: break;
257:
258: case SSH_CMSG_MAX_PACKET_SIZE:
259: if (packet_set_maxsize(packet_get_int()) > 0)
260: success = 1;
261: break;
262:
263: case SSH_CMSG_EXEC_SHELL:
264: case SSH_CMSG_EXEC_CMD:
265: if (type == SSH_CMSG_EXEC_CMD) {
266: command = packet_get_string(&dlen);
267: debug("Exec command '%.500s'", command);
268: packet_integrity_check(plen, 4 + dlen, type);
269: } else {
270: command = NULL;
271: packet_integrity_check(plen, 0, type);
272: }
273: if (forced_command != NULL) {
1.34 markus 274: original_command = command;
1.1 markus 275: command = forced_command;
276: debug("Forced command '%.500s'", forced_command);
277: }
1.86 markus 278: if (s->ttyfd != -1)
1.63 markus 279: do_exec_pty(s, command);
1.1 markus 280: else
1.63 markus 281: do_exec_no_pty(s, command);
1.1 markus 282: if (command != NULL)
283: xfree(command);
1.82 markus 284: session_close(s);
1.1 markus 285: return;
286:
287: default:
288: /*
289: * Any unknown messages in this phase are ignored,
290: * and a failure message is returned.
291: */
292: log("Unknown packet type received after authentication: %d", type);
293: }
294: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
295: packet_send();
296: packet_write_wait();
297:
298: /* Enable compression now that we have replied if appropriate. */
299: if (enable_compression_after_reply) {
300: enable_compression_after_reply = 0;
301: packet_start_compression(compression_level);
302: }
303: }
304: }
305:
306: /*
307: * This is called to fork and execute a command when we have no tty. This
308: * will call do_child from the child, and server_loop from the parent after
309: * setting up file descriptors and such.
310: */
1.4 markus 311: void
1.63 markus 312: do_exec_no_pty(Session *s, const char *command)
1.1 markus 313: {
314: int pid;
315:
316: #ifdef USE_PIPES
317: int pin[2], pout[2], perr[2];
318: /* Allocate pipes for communicating with the program. */
319: if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
320: packet_disconnect("Could not create pipes: %.100s",
321: strerror(errno));
322: #else /* USE_PIPES */
323: int inout[2], err[2];
324: /* Uses socket pairs to communicate with the program. */
325: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
326: socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
327: packet_disconnect("Could not create socket pairs: %.100s",
328: strerror(errno));
329: #endif /* USE_PIPES */
330: if (s == NULL)
331: fatal("do_exec_no_pty: no session");
332:
1.9 markus 333: session_proctitle(s);
1.1 markus 334:
335: /* Fork the child. */
336: if ((pid = fork()) == 0) {
337: /* Child. Reinitialize the log since the pid has changed. */
338: log_init(__progname, options.log_level, options.log_facility, log_stderr);
339:
340: /*
341: * Create a new session and process group since the 4.4BSD
342: * setlogin() affects the entire process group.
343: */
344: if (setsid() < 0)
345: error("setsid failed: %.100s", strerror(errno));
346:
347: #ifdef USE_PIPES
348: /*
349: * Redirect stdin. We close the parent side of the socket
350: * pair, and make the child side the standard input.
351: */
352: close(pin[1]);
353: if (dup2(pin[0], 0) < 0)
354: perror("dup2 stdin");
355: close(pin[0]);
356:
357: /* Redirect stdout. */
358: close(pout[0]);
359: if (dup2(pout[1], 1) < 0)
360: perror("dup2 stdout");
361: close(pout[1]);
362:
363: /* Redirect stderr. */
364: close(perr[0]);
365: if (dup2(perr[1], 2) < 0)
366: perror("dup2 stderr");
367: close(perr[1]);
368: #else /* USE_PIPES */
369: /*
370: * Redirect stdin, stdout, and stderr. Stdin and stdout will
371: * use the same socket, as some programs (particularly rdist)
372: * seem to depend on it.
373: */
374: close(inout[1]);
375: close(err[1]);
376: if (dup2(inout[0], 0) < 0) /* stdin */
377: perror("dup2 stdin");
378: if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
379: perror("dup2 stdout");
380: if (dup2(err[0], 2) < 0) /* stderr */
381: perror("dup2 stderr");
382: #endif /* USE_PIPES */
383:
384: /* Do processing for the child (exec command etc). */
1.60 markus 385: do_child(s, command);
1.1 markus 386: /* NOTREACHED */
387: }
388: if (pid < 0)
389: packet_disconnect("fork failed: %.100s", strerror(errno));
390: s->pid = pid;
1.47 markus 391: /* Set interactive/non-interactive mode. */
1.48 markus 392: packet_set_interactive(s->display != NULL);
1.1 markus 393: #ifdef USE_PIPES
394: /* We are the parent. Close the child sides of the pipes. */
395: close(pin[0]);
396: close(pout[1]);
397: close(perr[1]);
398:
1.2 markus 399: if (compat20) {
1.64 markus 400: session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
1.2 markus 401: } else {
402: /* Enter the interactive session. */
403: server_loop(pid, pin[1], pout[0], perr[0]);
1.64 markus 404: /* server_loop has closed pin[1], pout[0], and perr[0]. */
1.2 markus 405: }
1.1 markus 406: #else /* USE_PIPES */
407: /* We are the parent. Close the child sides of the socket pairs. */
408: close(inout[0]);
409: close(err[0]);
410:
411: /*
412: * Enter the interactive session. Note: server_loop must be able to
413: * handle the case that fdin and fdout are the same.
414: */
1.2 markus 415: if (compat20) {
1.64 markus 416: session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
1.2 markus 417: } else {
418: server_loop(pid, inout[1], inout[1], err[1]);
419: /* server_loop has closed inout[1] and err[1]. */
420: }
1.1 markus 421: #endif /* USE_PIPES */
422: }
423:
424: /*
425: * This is called to fork and execute a command when we have a tty. This
426: * will call do_child from the child, and server_loop from the parent after
427: * setting up file descriptors, controlling tty, updating wtmp, utmp,
428: * lastlog, and other such operations.
429: */
1.4 markus 430: void
1.63 markus 431: do_exec_pty(Session *s, const char *command)
1.1 markus 432: {
433: int fdout, ptyfd, ttyfd, ptymaster;
434: pid_t pid;
435:
436: if (s == NULL)
437: fatal("do_exec_pty: no session");
438: ptyfd = s->ptyfd;
439: ttyfd = s->ttyfd;
440:
441: /* Fork the child. */
442: if ((pid = fork()) == 0) {
1.24 markus 443: /* Child. Reinitialize the log because the pid has changed. */
1.1 markus 444: log_init(__progname, options.log_level, options.log_facility, log_stderr);
445:
446: /* Close the master side of the pseudo tty. */
447: close(ptyfd);
448:
449: /* Make the pseudo tty our controlling tty. */
450: pty_make_controlling_tty(&ttyfd, s->tty);
451:
452: /* Redirect stdin from the pseudo tty. */
453: if (dup2(ttyfd, fileno(stdin)) < 0)
454: error("dup2 stdin failed: %.100s", strerror(errno));
455:
456: /* Redirect stdout to the pseudo tty. */
457: if (dup2(ttyfd, fileno(stdout)) < 0)
458: error("dup2 stdin failed: %.100s", strerror(errno));
459:
460: /* Redirect stderr to the pseudo tty. */
461: if (dup2(ttyfd, fileno(stderr)) < 0)
462: error("dup2 stdin failed: %.100s", strerror(errno));
463:
464: /* Close the extra descriptor for the pseudo tty. */
465: close(ttyfd);
466:
1.24 markus 467: /* record login, etc. similar to login(1) */
1.41 markus 468: if (!(options.use_login && command == NULL))
469: do_login(s, command);
1.1 markus 470:
471: /* Do common processing for the child, such as execing the command. */
1.60 markus 472: do_child(s, command);
1.1 markus 473: /* NOTREACHED */
474: }
475: if (pid < 0)
476: packet_disconnect("fork failed: %.100s", strerror(errno));
477: s->pid = pid;
478:
479: /* Parent. Close the slave side of the pseudo tty. */
480: close(ttyfd);
481:
482: /*
483: * Create another descriptor of the pty master side for use as the
484: * standard input. We could use the original descriptor, but this
485: * simplifies code in server_loop. The descriptor is bidirectional.
486: */
487: fdout = dup(ptyfd);
488: if (fdout < 0)
489: packet_disconnect("dup #1 failed: %.100s", strerror(errno));
490:
491: /* we keep a reference to the pty master */
492: ptymaster = dup(ptyfd);
493: if (ptymaster < 0)
494: packet_disconnect("dup #2 failed: %.100s", strerror(errno));
495: s->ptymaster = ptymaster;
496:
497: /* Enter interactive session. */
1.47 markus 498: packet_set_interactive(1);
1.2 markus 499: if (compat20) {
500: session_set_fds(s, ptyfd, fdout, -1);
501: } else {
502: server_loop(pid, ptyfd, fdout, -1);
503: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 504: }
505: }
506:
507: /* administrative, login(1)-like work */
508: void
1.41 markus 509: do_login(Session *s, const char *command)
1.24 markus 510: {
511: char *time_string;
1.35 markus 512: char hostname[MAXHOSTNAMELEN];
1.24 markus 513: socklen_t fromlen;
514: struct sockaddr_storage from;
515: time_t last_login_time;
516: struct passwd * pw = s->pw;
517: pid_t pid = getpid();
518:
519: /*
520: * Get IP address of client. If the connection is not a socket, let
521: * the address be 0.0.0.0.
522: */
523: memset(&from, 0, sizeof(from));
524: if (packet_connection_is_on_socket()) {
525: fromlen = sizeof(from);
526: if (getpeername(packet_get_connection_in(),
527: (struct sockaddr *) & from, &fromlen) < 0) {
528: debug("getpeername: %.100s", strerror(errno));
529: fatal_cleanup();
530: }
531: }
1.25 markus 532:
1.35 markus 533: /* Get the time and hostname when the user last logged in. */
1.69 stevesk 534: if (options.print_lastlog) {
535: hostname[0] = '\0';
536: last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
537: hostname, sizeof(hostname));
538: }
1.35 markus 539:
1.24 markus 540: /* Record that there was a login on that tty from the remote host. */
541: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
1.70 stevesk 542: get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
543: (struct sockaddr *)&from);
1.24 markus 544:
1.73 djm 545: if (check_quietlogin(s, command))
1.24 markus 546: return;
1.73 djm 547:
1.69 stevesk 548: if (options.print_lastlog && last_login_time != 0) {
1.24 markus 549: time_string = ctime(&last_login_time);
550: if (strchr(time_string, '\n'))
551: *strchr(time_string, '\n') = 0;
1.40 markus 552: if (strcmp(hostname, "") == 0)
1.24 markus 553: printf("Last login: %s\r\n", time_string);
554: else
1.36 markus 555: printf("Last login: %s from %s\r\n", time_string, hostname);
1.24 markus 556: }
1.73 djm 557:
558: do_motd();
559: }
560:
561: /*
562: * Display the message of the day.
563: */
564: void
565: do_motd(void)
566: {
567: FILE *f;
568: char buf[256];
569:
1.24 markus 570: if (options.print_motd) {
1.28 millert 571: #ifdef HAVE_LOGIN_CAP
572: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
573: "/etc/motd"), "r");
574: #else
1.24 markus 575: f = fopen("/etc/motd", "r");
1.28 millert 576: #endif
1.24 markus 577: if (f) {
578: while (fgets(buf, sizeof(buf), f))
579: fputs(buf, stdout);
580: fclose(f);
581: }
1.2 markus 582: }
1.73 djm 583: }
584:
585:
586: /*
587: * Check for quiet login, either .hushlogin or command given.
588: */
589: int
590: check_quietlogin(Session *s, const char *command)
591: {
592: char buf[256];
593: struct passwd * pw = s->pw;
594: struct stat st;
595:
596: /* Return 1 if .hushlogin exists or a command given. */
597: if (command != NULL)
598: return 1;
599: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
600: #ifdef HAVE_LOGIN_CAP
601: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
602: return 1;
603: #else
604: if (stat(buf, &st) >= 0)
605: return 1;
606: #endif
607: return 0;
1.1 markus 608: }
609:
610: /*
611: * Sets the value of the given variable in the environment. If the variable
612: * already exists, its value is overriden.
613: */
1.4 markus 614: void
1.45 markus 615: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.1 markus 616: const char *value)
617: {
1.45 markus 618: u_int i, namelen;
1.1 markus 619: char **env;
620:
621: /*
622: * Find the slot where the value should be stored. If the variable
623: * already exists, we reuse the slot; otherwise we append a new slot
624: * at the end of the array, expanding if necessary.
625: */
626: env = *envp;
627: namelen = strlen(name);
628: for (i = 0; env[i]; i++)
629: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
630: break;
631: if (env[i]) {
632: /* Reuse the slot. */
633: xfree(env[i]);
634: } else {
635: /* New variable. Expand if necessary. */
636: if (i >= (*envsizep) - 1) {
637: (*envsizep) += 50;
638: env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
639: }
640: /* Need to set the NULL pointer at end of array beyond the new slot. */
641: env[i + 1] = NULL;
642: }
643:
644: /* Allocate space and format the variable in the appropriate slot. */
645: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
646: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
647: }
648:
649: /*
650: * Reads environment variables from the given file and adds/overrides them
651: * into the environment. If the file does not exist, this does nothing.
652: * Otherwise, it must consist of empty lines, comments (line starts with '#')
653: * and assignments of the form name=value. No other forms are allowed.
654: */
1.4 markus 655: void
1.45 markus 656: read_environment_file(char ***env, u_int *envsize,
1.1 markus 657: const char *filename)
658: {
659: FILE *f;
660: char buf[4096];
661: char *cp, *value;
662:
663: f = fopen(filename, "r");
664: if (!f)
665: return;
666:
667: while (fgets(buf, sizeof(buf), f)) {
668: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
669: ;
670: if (!*cp || *cp == '#' || *cp == '\n')
671: continue;
672: if (strchr(cp, '\n'))
673: *strchr(cp, '\n') = '\0';
674: value = strchr(cp, '=');
675: if (value == NULL) {
676: fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
677: continue;
678: }
1.14 deraadt 679: /*
680: * Replace the equals sign by nul, and advance value to
681: * the value string.
682: */
1.1 markus 683: *value = '\0';
684: value++;
685: child_set_env(env, envsize, cp, value);
686: }
687: fclose(f);
688: }
689:
690: /*
691: * Performs common processing for the child, such as setting up the
692: * environment, closing extra file descriptors, setting the user and group
693: * ids, and executing the command or shell.
694: */
1.4 markus 695: void
1.60 markus 696: do_child(Session *s, const char *command)
1.1 markus 697: {
1.32 markus 698: const char *shell, *hostname = NULL, *cp = NULL;
1.60 markus 699: struct passwd * pw = s->pw;
1.1 markus 700: char buf[256];
1.16 markus 701: char cmd[1024];
1.27 millert 702: FILE *f = NULL;
1.45 markus 703: u_int envsize, i;
1.1 markus 704: char **env;
705: extern char **environ;
706: struct stat st;
707: char *argv[10];
1.84 markus 708: int do_xauth;
709:
710: do_xauth =
711: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1.17 markus 712:
1.74 markus 713: /* remove hostkey from the child's memory */
714: destroy_sensitive_data();
715:
1.17 markus 716: /* login(1) is only called if we execute the login shell */
717: if (options.use_login && command != NULL)
718: options.use_login = 0;
1.1 markus 719:
1.27 millert 720: if (!options.use_login) {
1.28 millert 721: #ifdef HAVE_LOGIN_CAP
722: if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
723: f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
724: _PATH_NOLOGIN), "r");
725: #else
1.27 millert 726: if (pw->pw_uid)
727: f = fopen(_PATH_NOLOGIN, "r");
1.28 millert 728: #endif
1.27 millert 729: if (f) {
730: /* /etc/nologin exists. Print its contents and exit. */
731: while (fgets(buf, sizeof(buf), f))
732: fputs(buf, stderr);
733: fclose(f);
1.1 markus 734: exit(254);
1.27 millert 735: }
1.1 markus 736: }
1.28 millert 737: /* Set login name, uid, gid, and groups. */
1.1 markus 738: /* Login(1) does this as well, and it needs uid 0 for the "-h"
739: switch, so we let login(1) to this for us. */
740: if (!options.use_login) {
741: if (getuid() == 0 || geteuid() == 0) {
1.28 millert 742: #ifdef HAVE_LOGIN_CAP
743: if (setusercontext(lc, pw, pw->pw_uid,
744: (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
745: perror("unable to set user context");
746: exit(1);
747: }
748: #else
749: if (setlogin(pw->pw_name) < 0)
750: error("setlogin failed: %s", strerror(errno));
1.1 markus 751: if (setgid(pw->pw_gid) < 0) {
752: perror("setgid");
753: exit(1);
754: }
755: /* Initialize the group list. */
756: if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
757: perror("initgroups");
758: exit(1);
759: }
760: endgrent();
761:
762: /* Permanently switch to the desired uid. */
1.71 markus 763: permanently_set_uid(pw);
1.28 millert 764: #endif
1.1 markus 765: }
766: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1.31 deraadt 767: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1.1 markus 768: }
769: /*
770: * Get the shell from the password data. An empty shell field is
771: * legal, and means /bin/sh.
772: */
773: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.28 millert 774: #ifdef HAVE_LOGIN_CAP
775: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
776: #endif
1.1 markus 777:
778: #ifdef AFS
779: /* Try to get AFS tokens for the local cell. */
780: if (k_hasafs()) {
781: char cell[64];
782:
783: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
784: krb_afslog(cell, 0);
785:
786: krb_afslog(0, 0);
787: }
788: #endif /* AFS */
789:
790: /* Initialize the environment. */
791: envsize = 100;
792: env = xmalloc(envsize * sizeof(char *));
793: env[0] = NULL;
794:
795: if (!options.use_login) {
796: /* Set basic environment. */
797: child_set_env(&env, &envsize, "USER", pw->pw_name);
798: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
799: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.28 millert 800: #ifdef HAVE_LOGIN_CAP
1.29 millert 801: (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
802: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.28 millert 803: #else
1.29 millert 804: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1.28 millert 805: #endif
1.1 markus 806:
807: snprintf(buf, sizeof buf, "%.200s/%.50s",
808: _PATH_MAILDIR, pw->pw_name);
809: child_set_env(&env, &envsize, "MAIL", buf);
810:
811: /* Normal systems set SHELL by default. */
812: child_set_env(&env, &envsize, "SHELL", shell);
813: }
814: if (getenv("TZ"))
815: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
816:
817: /* Set custom environment options from RSA authentication. */
818: while (custom_environment) {
819: struct envstring *ce = custom_environment;
820: char *s = ce->s;
821: int i;
822: for (i = 0; s[i] != '=' && s[i]; i++);
823: if (s[i] == '=') {
824: s[i] = 0;
825: child_set_env(&env, &envsize, s, s + i + 1);
826: }
827: custom_environment = ce->next;
828: xfree(ce->s);
829: xfree(ce);
830: }
831:
832: snprintf(buf, sizeof buf, "%.50s %d %d",
833: get_remote_ipaddr(), get_remote_port(), get_local_port());
834: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
835:
1.60 markus 836: if (s->ttyfd != -1)
837: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
838: if (s->term)
839: child_set_env(&env, &envsize, "TERM", s->term);
840: if (s->display)
841: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 842: if (original_command)
843: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
844: original_command);
1.1 markus 845:
846: #ifdef KRB4
847: {
848: extern char *ticket;
849:
850: if (ticket)
851: child_set_env(&env, &envsize, "KRBTKFILE", ticket);
852: }
853: #endif /* KRB4 */
854:
855: if (auth_get_socket_name() != NULL)
856: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
857: auth_get_socket_name());
858:
859: /* read $HOME/.ssh/environment. */
860: if (!options.use_login) {
1.14 deraadt 861: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
862: pw->pw_dir);
1.1 markus 863: read_environment_file(&env, &envsize, buf);
864: }
865: if (debug_flag) {
866: /* dump the environment */
867: fprintf(stderr, "Environment:\n");
868: for (i = 0; env[i]; i++)
869: fprintf(stderr, " %.200s\n", env[i]);
870: }
1.26 millert 871: /* we have to stash the hostname before we close our socket. */
872: if (options.use_login)
1.70 stevesk 873: hostname = get_remote_name_or_ip(utmp_len,
874: options.reverse_mapping_check);
1.1 markus 875: /*
876: * Close the connection descriptors; note that this is the child, and
877: * the server will still have the socket open, and it is important
878: * that we do not shutdown it. Note that the descriptors cannot be
879: * closed before building the environment, as we call
880: * get_remote_ipaddr there.
881: */
882: if (packet_get_connection_in() == packet_get_connection_out())
883: close(packet_get_connection_in());
884: else {
885: close(packet_get_connection_in());
886: close(packet_get_connection_out());
887: }
888: /*
889: * Close all descriptors related to channels. They will still remain
890: * open in the parent.
891: */
892: /* XXX better use close-on-exec? -markus */
893: channel_close_all();
894:
895: /*
896: * Close any extra file descriptors. Note that there may still be
897: * descriptors left by system functions. They will be closed later.
898: */
899: endpwent();
900:
901: /*
902: * Close any extra open file descriptors so that we don\'t have them
903: * hanging around in clients. Note that we want to do this after
904: * initgroups, because at least on Solaris 2.3 it leaves file
905: * descriptors open.
906: */
907: for (i = 3; i < 64; i++)
908: close(i);
909:
910: /* Change current directory to the user\'s home directory. */
1.28 millert 911: if (chdir(pw->pw_dir) < 0) {
1.1 markus 912: fprintf(stderr, "Could not chdir to home directory %s: %s\n",
913: pw->pw_dir, strerror(errno));
1.28 millert 914: #ifdef HAVE_LOGIN_CAP
915: if (login_getcapbool(lc, "requirehome", 0))
916: exit(1);
917: #endif
918: }
1.1 markus 919:
920: /*
921: * Must take new environment into use so that .ssh/rc, /etc/sshrc and
922: * xauth are run in the proper environment.
923: */
924: environ = env;
925:
926: /*
927: * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
928: * in this order).
929: */
930: if (!options.use_login) {
1.74 markus 931: /* ignore _PATH_SSH_USER_RC for subsystems */
932: if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1.75 markus 933: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
934: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1.1 markus 935: if (debug_flag)
1.75 markus 936: fprintf(stderr, "Running %s\n", cmd);
937: f = popen(cmd, "w");
1.1 markus 938: if (f) {
1.60 markus 939: if (do_xauth)
940: fprintf(f, "%s %s\n", s->auth_proto,
941: s->auth_data);
1.1 markus 942: pclose(f);
943: } else
1.60 markus 944: fprintf(stderr, "Could not run %s\n",
945: _PATH_SSH_USER_RC);
1.50 markus 946: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1.1 markus 947: if (debug_flag)
1.60 markus 948: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
949: _PATH_SSH_SYSTEM_RC);
1.50 markus 950: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1.1 markus 951: if (f) {
1.60 markus 952: if (do_xauth)
953: fprintf(f, "%s %s\n", s->auth_proto,
954: s->auth_data);
1.1 markus 955: pclose(f);
956: } else
1.60 markus 957: fprintf(stderr, "Could not run %s\n",
958: _PATH_SSH_SYSTEM_RC);
959: } else if (do_xauth && options.xauth_location != NULL) {
1.1 markus 960: /* Add authority data to .Xauthority if appropriate. */
1.60 markus 961: char *screen = strchr(s->display, ':');
962:
963: if (debug_flag) {
964: fprintf(stderr,
965: "Running %.100s add "
966: "%.100s %.100s %.100s\n",
967: options.xauth_location, s->display,
968: s->auth_proto, s->auth_data);
969: if (screen != NULL)
1.14 deraadt 970: fprintf(stderr,
1.60 markus 971: "Adding %.*s/unix%s %s %s\n",
972: (int)(screen - s->display),
973: s->display, screen,
974: s->auth_proto, s->auth_data);
975: }
976: snprintf(cmd, sizeof cmd, "%s -q -",
977: options.xauth_location);
978: f = popen(cmd, "w");
979: if (f) {
980: fprintf(f, "add %s %s %s\n", s->display,
981: s->auth_proto, s->auth_data);
982: if (screen != NULL)
983: fprintf(f, "add %.*s/unix%s %s %s\n",
984: (int)(screen - s->display),
985: s->display, screen,
986: s->auth_proto,
987: s->auth_data);
988: pclose(f);
989: } else {
990: fprintf(stderr, "Could not run %s\n",
991: cmd);
1.1 markus 992: }
993: }
994: /* Get the last component of the shell name. */
995: cp = strrchr(shell, '/');
996: if (cp)
997: cp++;
998: else
999: cp = shell;
1000: }
1.67 markus 1001:
1002: /* restore SIGPIPE for child */
1003: signal(SIGPIPE, SIG_DFL);
1004:
1.1 markus 1005: /*
1006: * If we have no command, execute the shell. In this case, the shell
1007: * name to be passed in argv[0] is preceded by '-' to indicate that
1008: * this is a login shell.
1009: */
1010: if (!command) {
1011: if (!options.use_login) {
1012: char buf[256];
1013:
1014: /*
1015: * Check for mail if we have a tty and it was enabled
1016: * in server options.
1017: */
1.60 markus 1018: if (s->ttyfd != -1 && options.check_mail) {
1.1 markus 1019: char *mailbox;
1020: struct stat mailstat;
1.60 markus 1021:
1.1 markus 1022: mailbox = getenv("MAIL");
1023: if (mailbox != NULL) {
1.14 deraadt 1024: if (stat(mailbox, &mailstat) != 0 ||
1025: mailstat.st_size == 0)
1.1 markus 1026: printf("No mail.\n");
1027: else if (mailstat.st_mtime < mailstat.st_atime)
1028: printf("You have mail.\n");
1029: else
1030: printf("You have new mail.\n");
1031: }
1032: }
1033: /* Start the shell. Set initial character to '-'. */
1034: buf[0] = '-';
1035: strncpy(buf + 1, cp, sizeof(buf) - 1);
1036: buf[sizeof(buf) - 1] = 0;
1037:
1038: /* Execute the shell. */
1039: argv[0] = buf;
1040: argv[1] = NULL;
1041: execve(shell, argv, env);
1042:
1043: /* Executing the shell failed. */
1044: perror(shell);
1045: exit(1);
1046:
1047: } else {
1048: /* Launch login(1). */
1049:
1.26 millert 1050: execl("/usr/bin/login", "login", "-h", hostname,
1.25 markus 1051: "-p", "-f", "--", pw->pw_name, NULL);
1.1 markus 1052:
1053: /* Login couldn't be executed, die. */
1054:
1055: perror("login");
1056: exit(1);
1057: }
1058: }
1059: /*
1060: * Execute the command using the user's shell. This uses the -c
1061: * option to execute the command.
1062: */
1063: argv[0] = (char *) cp;
1064: argv[1] = "-c";
1065: argv[2] = (char *) command;
1066: argv[3] = NULL;
1067: execve(shell, argv, env);
1068: perror(shell);
1069: exit(1);
1070: }
1071:
1072: Session *
1073: session_new(void)
1074: {
1075: int i;
1076: static int did_init = 0;
1077: if (!did_init) {
1078: debug("session_new: init");
1079: for(i = 0; i < MAX_SESSIONS; i++) {
1080: sessions[i].used = 0;
1081: }
1082: did_init = 1;
1083: }
1084: for(i = 0; i < MAX_SESSIONS; i++) {
1085: Session *s = &sessions[i];
1086: if (! s->used) {
1.68 djm 1087: memset(s, 0, sizeof(*s));
1.1 markus 1088: s->chanid = -1;
1089: s->ptyfd = -1;
1090: s->ttyfd = -1;
1091: s->used = 1;
1.85 markus 1092: s->self = i;
1.1 markus 1093: debug("session_new: session %d", i);
1094: return s;
1095: }
1096: }
1097: return NULL;
1098: }
1099:
1100: void
1101: session_dump(void)
1102: {
1103: int i;
1104: for(i = 0; i < MAX_SESSIONS; i++) {
1105: Session *s = &sessions[i];
1106: debug("dump: used %d session %d %p channel %d pid %d",
1107: s->used,
1108: s->self,
1109: s,
1110: s->chanid,
1111: s->pid);
1112: }
1113: }
1114:
1.2 markus 1115: int
1116: session_open(int chanid)
1117: {
1118: Session *s = session_new();
1119: debug("session_open: channel %d", chanid);
1120: if (s == NULL) {
1121: error("no more sessions");
1122: return 0;
1123: }
1.7 markus 1124: s->pw = auth_get_user();
1125: if (s->pw == NULL)
1.54 stevesk 1126: fatal("no user for session %d", s->self);
1.2 markus 1127: debug("session_open: session %d: link with channel %d", s->self, chanid);
1128: s->chanid = chanid;
1129: return 1;
1130: }
1131:
1132: Session *
1133: session_by_channel(int id)
1134: {
1135: int i;
1136: for(i = 0; i < MAX_SESSIONS; i++) {
1137: Session *s = &sessions[i];
1138: if (s->used && s->chanid == id) {
1139: debug("session_by_channel: session %d channel %d", i, id);
1140: return s;
1141: }
1142: }
1143: debug("session_by_channel: unknown channel %d", id);
1144: session_dump();
1145: return NULL;
1146: }
1147:
1148: Session *
1149: session_by_pid(pid_t pid)
1150: {
1151: int i;
1152: debug("session_by_pid: pid %d", pid);
1153: for(i = 0; i < MAX_SESSIONS; i++) {
1154: Session *s = &sessions[i];
1155: if (s->used && s->pid == pid)
1156: return s;
1157: }
1158: error("session_by_pid: unknown pid %d", pid);
1159: session_dump();
1160: return NULL;
1161: }
1162:
1163: int
1164: session_window_change_req(Session *s)
1165: {
1166: s->col = packet_get_int();
1167: s->row = packet_get_int();
1168: s->xpixel = packet_get_int();
1169: s->ypixel = packet_get_int();
1.3 markus 1170: packet_done();
1.2 markus 1171: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1172: return 1;
1173: }
1174:
1175: int
1176: session_pty_req(Session *s)
1177: {
1.45 markus 1178: u_int len;
1.72 stevesk 1179: int n_bytes;
1.2 markus 1180:
1.86 markus 1181: if (no_pty_flag) {
1182: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1183: return 0;
1.86 markus 1184: }
1185: if (s->ttyfd != -1) {
1186: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1187: return 0;
1.86 markus 1188: }
1189:
1.2 markus 1190: s->term = packet_get_string(&len);
1.86 markus 1191:
1192: if (compat20) {
1193: s->col = packet_get_int();
1194: s->row = packet_get_int();
1195: } else {
1196: s->row = packet_get_int();
1197: s->col = packet_get_int();
1198: }
1.2 markus 1199: s->xpixel = packet_get_int();
1200: s->ypixel = packet_get_int();
1201:
1202: if (strcmp(s->term, "") == 0) {
1203: xfree(s->term);
1204: s->term = NULL;
1205: }
1.86 markus 1206:
1.2 markus 1207: /* Allocate a pty and open it. */
1.86 markus 1208: debug("Allocating pty.");
1.2 markus 1209: if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1.86 markus 1210: if (s->term)
1211: xfree(s->term);
1.2 markus 1212: s->term = NULL;
1213: s->ptyfd = -1;
1214: s->ttyfd = -1;
1215: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1216: return 0;
1.2 markus 1217: }
1218: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1219:
1220: /* for SSH1 the tty modes length is not given */
1221: if (!compat20)
1222: n_bytes = packet_remaining();
1223: tty_parse_modes(s->ttyfd, &n_bytes);
1224:
1.2 markus 1225: /*
1226: * Add a cleanup function to clear the utmp entry and record logout
1227: * time in case we call fatal() (e.g., the connection gets closed).
1228: */
1.85 markus 1229: fatal_add_cleanup(session_pty_cleanup, (void *)s);
1.2 markus 1230: pty_setowner(s->pw, s->tty);
1.86 markus 1231:
1232: /* Set window size from the packet. */
1.2 markus 1233: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1234:
1.72 stevesk 1235: packet_done();
1.9 markus 1236: session_proctitle(s);
1.2 markus 1237: return 1;
1238: }
1239:
1.7 markus 1240: int
1241: session_subsystem_req(Session *s)
1242: {
1.45 markus 1243: u_int len;
1.7 markus 1244: int success = 0;
1245: char *subsys = packet_get_string(&len);
1.18 jakob 1246: int i;
1.7 markus 1247:
1248: packet_done();
1249: log("subsystem request for %s", subsys);
1.18 jakob 1250:
1251: for (i = 0; i < options.num_subsystems; i++) {
1252: if(strcmp(subsys, options.subsystem_name[i]) == 0) {
1253: debug("subsystem: exec() %s", options.subsystem_command[i]);
1.64 markus 1254: s->is_subsystem = 1;
1.63 markus 1255: do_exec_no_pty(s, options.subsystem_command[i]);
1.18 jakob 1256: success = 1;
1257: }
1258: }
1259:
1260: if (!success)
1261: log("subsystem request for %s failed, subsystem not found", subsys);
1.7 markus 1262:
1263: xfree(subsys);
1264: return success;
1265: }
1266:
1267: int
1268: session_x11_req(Session *s)
1269: {
1.81 markus 1270: int success;
1.7 markus 1271:
1272: s->single_connection = packet_get_char();
1273: s->auth_proto = packet_get_string(NULL);
1274: s->auth_data = packet_get_string(NULL);
1275: s->screen = packet_get_int();
1276: packet_done();
1277:
1.81 markus 1278: success = session_setup_x11fwd(s);
1279: if (!success) {
1.7 markus 1280: xfree(s->auth_proto);
1281: xfree(s->auth_data);
1.84 markus 1282: s->auth_proto = NULL;
1283: s->auth_data = NULL;
1.7 markus 1284: }
1.81 markus 1285: return success;
1.7 markus 1286: }
1287:
1.19 markus 1288: int
1289: session_shell_req(Session *s)
1290: {
1291: /* if forced_command == NULL, the shell is execed */
1292: char *shell = forced_command;
1293: packet_done();
1294: if (s->ttyfd == -1)
1.63 markus 1295: do_exec_no_pty(s, shell);
1.19 markus 1296: else
1.63 markus 1297: do_exec_pty(s, shell);
1.19 markus 1298: return 1;
1299: }
1300:
1301: int
1302: session_exec_req(Session *s)
1303: {
1.45 markus 1304: u_int len;
1.19 markus 1305: char *command = packet_get_string(&len);
1306: packet_done();
1307: if (forced_command) {
1.34 markus 1308: original_command = command;
1.19 markus 1309: command = forced_command;
1310: debug("Forced command '%.500s'", forced_command);
1311: }
1312: if (s->ttyfd == -1)
1.63 markus 1313: do_exec_no_pty(s, command);
1.19 markus 1314: else
1.63 markus 1315: do_exec_pty(s, command);
1.19 markus 1316: if (forced_command == NULL)
1317: xfree(command);
1318: return 1;
1319: }
1320:
1.43 markus 1321: int
1322: session_auth_agent_req(Session *s)
1323: {
1324: static int called = 0;
1325: packet_done();
1.44 markus 1326: if (no_agent_forwarding_flag) {
1327: debug("session_auth_agent_req: no_agent_forwarding_flag");
1328: return 0;
1329: }
1.43 markus 1330: if (called) {
1331: return 0;
1332: } else {
1333: called = 1;
1334: return auth_input_request_forwarding(s->pw);
1335: }
1336: }
1337:
1.2 markus 1338: void
1339: session_input_channel_req(int id, void *arg)
1340: {
1.45 markus 1341: u_int len;
1.2 markus 1342: int reply;
1343: int success = 0;
1344: char *rtype;
1345: Session *s;
1346: Channel *c;
1347:
1348: rtype = packet_get_string(&len);
1349: reply = packet_get_char();
1350:
1351: s = session_by_channel(id);
1352: if (s == NULL)
1353: fatal("session_input_channel_req: channel %d: no session", id);
1354: c = channel_lookup(id);
1355: if (c == NULL)
1356: fatal("session_input_channel_req: channel %d: bad channel", id);
1357:
1358: debug("session_input_channel_req: session %d channel %d request %s reply %d",
1359: s->self, id, rtype, reply);
1360:
1361: /*
1.64 markus 1362: * a session is in LARVAL state until a shell, a command
1363: * or a subsystem is executed
1.2 markus 1364: */
1365: if (c->type == SSH_CHANNEL_LARVAL) {
1366: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1367: success = session_shell_req(s);
1.2 markus 1368: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1369: success = session_exec_req(s);
1.2 markus 1370: } else if (strcmp(rtype, "pty-req") == 0) {
1.3 markus 1371: success = session_pty_req(s);
1.7 markus 1372: } else if (strcmp(rtype, "x11-req") == 0) {
1373: success = session_x11_req(s);
1.43 markus 1374: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1375: success = session_auth_agent_req(s);
1.7 markus 1376: } else if (strcmp(rtype, "subsystem") == 0) {
1377: success = session_subsystem_req(s);
1.2 markus 1378: }
1379: }
1380: if (strcmp(rtype, "window-change") == 0) {
1381: success = session_window_change_req(s);
1382: }
1383:
1384: if (reply) {
1385: packet_start(success ?
1386: SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1387: packet_put_int(c->remote_id);
1388: packet_send();
1389: }
1390: xfree(rtype);
1391: }
1392:
1393: void
1394: session_set_fds(Session *s, int fdin, int fdout, int fderr)
1395: {
1396: if (!compat20)
1397: fatal("session_set_fds: called for proto != 2.0");
1398: /*
1399: * now that have a child and a pipe to the child,
1400: * we can activate our channel and register the fd's
1401: */
1402: if (s->chanid == -1)
1403: fatal("no channel for session %d", s->self);
1404: channel_set_fds(s->chanid,
1405: fdout, fdin, fderr,
1.42 markus 1406: fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1407: 1);
1.2 markus 1408: }
1409:
1.85 markus 1410: /*
1411: * Function to perform pty cleanup. Also called if we get aborted abnormally
1412: * (e.g., due to a dropped connection).
1413: */
1.1 markus 1414: void
1.85 markus 1415: session_pty_cleanup(void *session)
1.1 markus 1416: {
1.85 markus 1417: Session *s = session;
1418:
1419: if (s == NULL) {
1420: error("session_pty_cleanup: no session");
1421: return;
1422: }
1423: if (s->ttyfd == -1)
1.1 markus 1424: return;
1425:
1.54 stevesk 1426: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1427:
1428: /* Record that the user has logged out. */
1.85 markus 1429: if (s->pid != 0)
1430: record_logout(s->pid, s->tty);
1.1 markus 1431:
1432: /* Release the pseudo-tty. */
1433: pty_release(s->tty);
1434:
1435: /*
1436: * Close the server side of the socket pairs. We must do this after
1437: * the pty cleanup, so that another process doesn't get this pty
1438: * while we're still cleaning up.
1439: */
1440: if (close(s->ptymaster) < 0)
1441: error("close(s->ptymaster): %s", strerror(errno));
1.2 markus 1442: }
1443:
1444: void
1445: session_exit_message(Session *s, int status)
1446: {
1447: Channel *c;
1448: if (s == NULL)
1449: fatal("session_close: no session");
1450: c = channel_lookup(s->chanid);
1451: if (c == NULL)
1.85 markus 1452: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 1453: s->self, s->chanid);
1454: debug("session_exit_message: session %d channel %d pid %d",
1455: s->self, s->chanid, s->pid);
1456:
1457: if (WIFEXITED(status)) {
1458: channel_request_start(s->chanid,
1459: "exit-status", 0);
1460: packet_put_int(WEXITSTATUS(status));
1461: packet_send();
1462: } else if (WIFSIGNALED(status)) {
1463: channel_request_start(s->chanid,
1464: "exit-signal", 0);
1465: packet_put_int(WTERMSIG(status));
1466: packet_put_char(WCOREDUMP(status));
1467: packet_put_cstring("");
1468: packet_put_cstring("");
1469: packet_send();
1470: } else {
1471: /* Some weird exit cause. Just exit. */
1472: packet_disconnect("wait returned status %04x.", status);
1473: }
1474:
1475: /* disconnect channel */
1476: debug("session_exit_message: release channel %d", s->chanid);
1477: channel_cancel_cleanup(s->chanid);
1.5 markus 1478: /*
1479: * emulate a write failure with 'chan_write_failed', nobody will be
1480: * interested in data we write.
1481: * Note that we must not call 'chan_read_failed', since there could
1482: * be some more data waiting in the pipe.
1483: */
1.8 markus 1484: if (c->ostate != CHAN_OUTPUT_CLOSED)
1485: chan_write_failed(c);
1.2 markus 1486: s->chanid = -1;
1487: }
1488:
1489: void
1.85 markus 1490: session_close(Session *s)
1.2 markus 1491: {
1.85 markus 1492: debug("session_close: session %d pid %d", s->self, s->pid);
1493: if (s->ttyfd != -1) {
1494: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1495: session_pty_cleanup(s);
1496: }
1.2 markus 1497: if (s->term)
1498: xfree(s->term);
1499: if (s->display)
1500: xfree(s->display);
1501: if (s->auth_data)
1502: xfree(s->auth_data);
1503: if (s->auth_proto)
1504: xfree(s->auth_proto);
1505: s->used = 0;
1.9 markus 1506: session_proctitle(s);
1.2 markus 1507: }
1508:
1509: void
1510: session_close_by_pid(pid_t pid, int status)
1511: {
1512: Session *s = session_by_pid(pid);
1513: if (s == NULL) {
1514: debug("session_close_by_pid: no session for pid %d", s->pid);
1515: return;
1516: }
1517: if (s->chanid != -1)
1518: session_exit_message(s, status);
1519: session_close(s);
1520: }
1521:
1522: /*
1523: * this is called when a channel dies before
1524: * the session 'child' itself dies
1525: */
1526: void
1527: session_close_by_channel(int id, void *arg)
1528: {
1529: Session *s = session_by_channel(id);
1530: if (s == NULL) {
1531: debug("session_close_by_channel: no session for channel %d", id);
1532: return;
1533: }
1534: /* disconnect channel */
1535: channel_cancel_cleanup(s->chanid);
1536: s->chanid = -1;
1537:
1538: debug("session_close_by_channel: channel %d kill %d", id, s->pid);
1539: if (s->pid == 0) {
1540: /* close session immediately */
1541: session_close(s);
1542: } else {
1543: /* notify child, delay session cleanup */
1544: if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0)
1545: error("session_close_by_channel: kill %d: %s",
1546: s->pid, strerror(errno));
1547: }
1.9 markus 1548: }
1549:
1550: char *
1551: session_tty_list(void)
1552: {
1553: static char buf[1024];
1554: int i;
1555: buf[0] = '\0';
1556: for(i = 0; i < MAX_SESSIONS; i++) {
1557: Session *s = &sessions[i];
1558: if (s->used && s->ttyfd != -1) {
1559: if (buf[0] != '\0')
1560: strlcat(buf, ",", sizeof buf);
1561: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1562: }
1563: }
1564: if (buf[0] == '\0')
1565: strlcpy(buf, "notty", sizeof buf);
1566: return buf;
1567: }
1568:
1569: void
1570: session_proctitle(Session *s)
1571: {
1572: if (s->pw == NULL)
1573: error("no user for session %d", s->self);
1574: else
1575: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 1576: }
1577:
1578: int
1579: session_setup_x11fwd(Session *s)
1580: {
1581: int fd;
1582: struct stat st;
1583:
1584: if (no_x11_forwarding_flag) {
1585: packet_send_debug("X11 forwarding disabled in user configuration file.");
1586: return 0;
1587: }
1588: if (!options.x11_forwarding) {
1589: debug("X11 forwarding disabled in server configuration file.");
1590: return 0;
1591: }
1592: if (!options.xauth_location ||
1593: (stat(options.xauth_location, &st) == -1)) {
1594: packet_send_debug("No xauth program; cannot forward with spoofing.");
1595: return 0;
1596: }
1.87 ! markus 1597: if (s->display != NULL) {
1.81 markus 1598: debug("X11 display already set.");
1599: return 0;
1600: }
1601: s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
1602: if (s->display == NULL) {
1.87 ! markus 1603: debug("x11_create_display_inet failed.");
1.81 markus 1604: return 0;
1605: }
1606: return 1;
1.2 markus 1607: }
1608:
1609: void
1.49 markus 1610: do_authenticated2(Authctxt *authctxt)
1.2 markus 1611: {
1612: server_loop2();
1.1 markus 1613: }
![[BACK]](/icons/back.gif){kind=icon}
Return to session.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh