Annotation of src/usr.bin/ssh/session.c, Revision 1.142
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.
1.95 markus 12: * Copyright (c) 2000, 2001 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"
1.142 ! deraadt 36: RCSID("$OpenBSD: session.c,v 1.141 2002/06/26 08:58:26 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"
1.130 provos 59: #include "monitor_wrap.h"
1.1 markus 60:
61: /* func */
62:
63: Session *session_new(void);
1.94 itojun 64: void session_set_fds(Session *, int, int, int);
1.130 provos 65: void session_pty_cleanup(void *);
1.94 itojun 66: void session_proctitle(Session *);
67: int session_setup_x11fwd(Session *);
68: void do_exec_pty(Session *, const char *);
69: void do_exec_no_pty(Session *, const char *);
70: void do_exec(Session *, const char *);
71: void do_login(Session *, const char *);
72: void do_child(Session *, const char *);
1.73 djm 73: void do_motd(void);
1.94 itojun 74: int check_quietlogin(Session *, const char *);
1.1 markus 75:
1.94 itojun 76: static void do_authenticated1(Authctxt *);
77: static void do_authenticated2(Authctxt *);
78:
79: static int session_pty_req(Session *);
1.65 markus 80:
1.1 markus 81: /* import */
82: extern ServerOptions options;
83: extern char *__progname;
84: extern int log_stderr;
85: extern int debug_flag;
1.45 markus 86: extern u_int utmp_len;
1.21 markus 87: extern int startup_pipe;
1.74 markus 88: extern void destroy_sensitive_data(void);
1.21 markus 89:
1.34 markus 90: /* original command from peer. */
1.92 markus 91: const char *original_command = NULL;
1.34 markus 92:
1.1 markus 93: /* data */
94: #define MAX_SESSIONS 10
95: Session sessions[MAX_SESSIONS];
96:
1.28 millert 97: #ifdef HAVE_LOGIN_CAP
1.129 provos 98: login_cap_t *lc;
1.28 millert 99: #endif
100:
1.136 markus 101: /* Name and directory of socket for authentication agent forwarding. */
102: static char *auth_sock_name = NULL;
103: static char *auth_sock_dir = NULL;
104:
105: /* removes the agent forwarding socket */
106:
107: static void
108: auth_sock_cleanup_proc(void *_pw)
109: {
110: struct passwd *pw = _pw;
111:
112: if (auth_sock_name != NULL) {
113: temporarily_use_uid(pw);
114: unlink(auth_sock_name);
115: rmdir(auth_sock_dir);
116: auth_sock_name = NULL;
117: restore_uid();
118: }
119: }
120:
121: static int
122: auth_input_request_forwarding(struct passwd * pw)
123: {
124: Channel *nc;
125: int sock;
126: struct sockaddr_un sunaddr;
127:
128: if (auth_sock_name != NULL) {
129: error("authentication forwarding requested twice.");
130: return 0;
131: }
132:
133: /* Temporarily drop privileged uid for mkdir/bind. */
134: temporarily_use_uid(pw);
135:
136: /* Allocate a buffer for the socket name, and format the name. */
137: auth_sock_name = xmalloc(MAXPATHLEN);
138: auth_sock_dir = xmalloc(MAXPATHLEN);
139: strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
140:
141: /* Create private directory for socket */
142: if (mkdtemp(auth_sock_dir) == NULL) {
143: packet_send_debug("Agent forwarding disabled: "
144: "mkdtemp() failed: %.100s", strerror(errno));
145: restore_uid();
146: xfree(auth_sock_name);
147: xfree(auth_sock_dir);
148: auth_sock_name = NULL;
149: auth_sock_dir = NULL;
150: return 0;
151: }
1.137 mpech 152: snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
153: auth_sock_dir, (long) getpid());
1.136 markus 154:
155: /* delete agent socket on fatal() */
156: fatal_add_cleanup(auth_sock_cleanup_proc, pw);
157:
158: /* Create the socket. */
159: sock = socket(AF_UNIX, SOCK_STREAM, 0);
160: if (sock < 0)
161: packet_disconnect("socket: %.100s", strerror(errno));
162:
163: /* Bind it to the name. */
164: memset(&sunaddr, 0, sizeof(sunaddr));
165: sunaddr.sun_family = AF_UNIX;
166: strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
167:
168: if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
169: packet_disconnect("bind: %.100s", strerror(errno));
170:
171: /* Restore the privileged uid. */
172: restore_uid();
173:
174: /* Start listening on the socket. */
175: if (listen(sock, 5) < 0)
176: packet_disconnect("listen: %.100s", strerror(errno));
177:
178: /* Allocate a channel for the authentication agent socket. */
179: nc = channel_new("auth socket",
180: SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
181: CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
182: 0, xstrdup("auth socket"), 1);
183: strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
184: return 1;
185: }
186:
187:
1.65 markus 188: void
189: do_authenticated(Authctxt *authctxt)
190: {
191: /*
192: * Cancel the alarm we set to limit the time taken for
193: * authentication.
194: */
195: alarm(0);
196: if (startup_pipe != -1) {
197: close(startup_pipe);
198: startup_pipe = -1;
199: }
200: /* setup the channel layer */
201: if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
202: channel_permit_all_opens();
203:
204: if (compat20)
205: do_authenticated2(authctxt);
206: else
207: do_authenticated1(authctxt);
1.79 markus 208:
1.87 markus 209: /* remove agent socket */
1.136 markus 210: if (auth_sock_name != NULL)
1.80 markus 211: auth_sock_cleanup_proc(authctxt->pw);
1.96 dugsong 212: #ifdef KRB4
213: if (options.kerberos_ticket_cleanup)
214: krb4_cleanup_proc(authctxt);
215: #endif
216: #ifdef KRB5
217: if (options.kerberos_ticket_cleanup)
218: krb5_cleanup_proc(authctxt);
219: #endif
1.65 markus 220: }
221:
1.1 markus 222: /*
223: * Prepares for an interactive session. This is called after the user has
224: * been successfully authenticated. During this message exchange, pseudo
225: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
226: * are requested, etc.
227: */
1.94 itojun 228: static void
1.65 markus 229: do_authenticated1(Authctxt *authctxt)
1.1 markus 230: {
231: Session *s;
1.65 markus 232: char *command;
1.117 markus 233: int success, type, screen_flag;
1.139 deraadt 234: int enable_compression_after_reply = 0;
235: u_int proto_len, data_len, dlen, compression_level = 0;
1.1 markus 236:
1.61 markus 237: s = session_new();
1.96 dugsong 238: s->authctxt = authctxt;
1.65 markus 239: s->pw = authctxt->pw;
1.28 millert 240:
1.1 markus 241: /*
242: * We stay in this loop until the client requests to execute a shell
243: * or a command.
244: */
245: for (;;) {
1.65 markus 246: success = 0;
1.1 markus 247:
248: /* Get a packet from the client. */
1.117 markus 249: type = packet_read();
1.1 markus 250:
251: /* Process the packet. */
252: switch (type) {
253: case SSH_CMSG_REQUEST_COMPRESSION:
254: compression_level = packet_get_int();
1.116 markus 255: packet_check_eom();
1.1 markus 256: if (compression_level < 1 || compression_level > 9) {
257: packet_send_debug("Received illegal compression level %d.",
1.112 deraadt 258: compression_level);
1.138 markus 259: break;
260: }
261: if (!options.compression) {
262: debug2("compression disabled");
1.1 markus 263: break;
264: }
265: /* Enable compression after we have responded with SUCCESS. */
266: enable_compression_after_reply = 1;
267: success = 1;
268: break;
269:
270: case SSH_CMSG_REQUEST_PTY:
1.86 markus 271: success = session_pty_req(s);
1.1 markus 272: break;
273:
274: case SSH_CMSG_X11_REQUEST_FORWARDING:
275: s->auth_proto = packet_get_string(&proto_len);
276: s->auth_data = packet_get_string(&data_len);
277:
1.57 markus 278: screen_flag = packet_get_protocol_flags() &
279: SSH_PROTOFLAG_SCREEN_NUMBER;
280: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
281:
282: if (packet_remaining() == 4) {
283: if (!screen_flag)
284: debug2("Buggy client: "
285: "X11 screen flag missing");
1.1 markus 286: s->screen = packet_get_int();
1.56 markus 287: } else {
1.1 markus 288: s->screen = 0;
1.56 markus 289: }
1.116 markus 290: packet_check_eom();
1.81 markus 291: success = session_setup_x11fwd(s);
292: if (!success) {
293: xfree(s->auth_proto);
294: xfree(s->auth_data);
1.84 markus 295: s->auth_proto = NULL;
296: s->auth_data = NULL;
1.1 markus 297: }
298: break;
299:
300: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
301: if (no_agent_forwarding_flag || compat13) {
302: debug("Authentication agent forwarding not permitted for this authentication.");
303: break;
304: }
305: debug("Received authentication agent forwarding request.");
1.65 markus 306: success = auth_input_request_forwarding(s->pw);
1.1 markus 307: break;
308:
309: case SSH_CMSG_PORT_FORWARD_REQUEST:
310: if (no_port_forwarding_flag) {
311: debug("Port forwarding not permitted for this authentication.");
1.39 markus 312: break;
313: }
314: if (!options.allow_tcp_forwarding) {
315: debug("Port forwarding not permitted.");
1.1 markus 316: break;
317: }
318: debug("Received TCP/IP port forwarding request.");
1.65 markus 319: channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
1.1 markus 320: success = 1;
321: break;
322:
323: case SSH_CMSG_MAX_PACKET_SIZE:
324: if (packet_set_maxsize(packet_get_int()) > 0)
325: success = 1;
326: break;
1.112 deraadt 327:
1.96 dugsong 328: #if defined(AFS) || defined(KRB5)
329: case SSH_CMSG_HAVE_KERBEROS_TGT:
330: if (!options.kerberos_tgt_passing) {
331: verbose("Kerberos TGT passing disabled.");
332: } else {
333: char *kdata = packet_get_string(&dlen);
1.116 markus 334: packet_check_eom();
1.112 deraadt 335:
1.96 dugsong 336: /* XXX - 0x41, see creds_to_radix version */
337: if (kdata[0] != 0x41) {
338: #ifdef KRB5
339: krb5_data tgt;
340: tgt.data = kdata;
341: tgt.length = dlen;
1.112 deraadt 342:
1.96 dugsong 343: if (auth_krb5_tgt(s->authctxt, &tgt))
344: success = 1;
345: else
346: verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
347: #endif /* KRB5 */
348: } else {
349: #ifdef AFS
350: if (auth_krb4_tgt(s->authctxt, kdata))
351: success = 1;
352: else
353: verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
354: #endif /* AFS */
355: }
356: xfree(kdata);
357: }
358: break;
359: #endif /* AFS || KRB5 */
1.112 deraadt 360:
1.96 dugsong 361: #ifdef AFS
362: case SSH_CMSG_HAVE_AFS_TOKEN:
363: if (!options.afs_token_passing || !k_hasafs()) {
364: verbose("AFS token passing disabled.");
365: } else {
366: /* Accept AFS token. */
367: char *token = packet_get_string(&dlen);
1.116 markus 368: packet_check_eom();
1.112 deraadt 369:
1.96 dugsong 370: if (auth_afs_token(s->authctxt, token))
371: success = 1;
372: else
373: verbose("AFS token refused for %.100s",
374: s->authctxt->user);
375: xfree(token);
376: }
377: break;
378: #endif /* AFS */
1.1 markus 379:
380: case SSH_CMSG_EXEC_SHELL:
381: case SSH_CMSG_EXEC_CMD:
382: if (type == SSH_CMSG_EXEC_CMD) {
383: command = packet_get_string(&dlen);
384: debug("Exec command '%.500s'", command);
1.92 markus 385: do_exec(s, command);
386: xfree(command);
1.1 markus 387: } else {
1.92 markus 388: do_exec(s, NULL);
1.1 markus 389: }
1.116 markus 390: packet_check_eom();
1.82 markus 391: session_close(s);
1.1 markus 392: return;
393:
394: default:
395: /*
396: * Any unknown messages in this phase are ignored,
397: * and a failure message is returned.
398: */
399: log("Unknown packet type received after authentication: %d", type);
400: }
401: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
402: packet_send();
403: packet_write_wait();
404:
405: /* Enable compression now that we have replied if appropriate. */
406: if (enable_compression_after_reply) {
407: enable_compression_after_reply = 0;
408: packet_start_compression(compression_level);
409: }
410: }
411: }
412:
413: /*
414: * This is called to fork and execute a command when we have no tty. This
415: * will call do_child from the child, and server_loop from the parent after
416: * setting up file descriptors and such.
417: */
1.4 markus 418: void
1.63 markus 419: do_exec_no_pty(Session *s, const char *command)
1.1 markus 420: {
1.137 mpech 421: pid_t pid;
1.1 markus 422:
423: #ifdef USE_PIPES
424: int pin[2], pout[2], perr[2];
425: /* Allocate pipes for communicating with the program. */
426: if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
427: packet_disconnect("Could not create pipes: %.100s",
428: strerror(errno));
429: #else /* USE_PIPES */
430: int inout[2], err[2];
431: /* Uses socket pairs to communicate with the program. */
432: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
433: socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
434: packet_disconnect("Could not create socket pairs: %.100s",
435: strerror(errno));
436: #endif /* USE_PIPES */
437: if (s == NULL)
438: fatal("do_exec_no_pty: no session");
439:
1.9 markus 440: session_proctitle(s);
1.1 markus 441:
442: /* Fork the child. */
443: if ((pid = fork()) == 0) {
444: /* Child. Reinitialize the log since the pid has changed. */
445: log_init(__progname, options.log_level, options.log_facility, log_stderr);
446:
447: /*
448: * Create a new session and process group since the 4.4BSD
449: * setlogin() affects the entire process group.
450: */
451: if (setsid() < 0)
452: error("setsid failed: %.100s", strerror(errno));
453:
454: #ifdef USE_PIPES
455: /*
456: * Redirect stdin. We close the parent side of the socket
457: * pair, and make the child side the standard input.
458: */
459: close(pin[1]);
460: if (dup2(pin[0], 0) < 0)
461: perror("dup2 stdin");
462: close(pin[0]);
463:
464: /* Redirect stdout. */
465: close(pout[0]);
466: if (dup2(pout[1], 1) < 0)
467: perror("dup2 stdout");
468: close(pout[1]);
469:
470: /* Redirect stderr. */
471: close(perr[0]);
472: if (dup2(perr[1], 2) < 0)
473: perror("dup2 stderr");
474: close(perr[1]);
475: #else /* USE_PIPES */
476: /*
477: * Redirect stdin, stdout, and stderr. Stdin and stdout will
478: * use the same socket, as some programs (particularly rdist)
479: * seem to depend on it.
480: */
481: close(inout[1]);
482: close(err[1]);
483: if (dup2(inout[0], 0) < 0) /* stdin */
484: perror("dup2 stdin");
485: if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
486: perror("dup2 stdout");
487: if (dup2(err[0], 2) < 0) /* stderr */
488: perror("dup2 stderr");
489: #endif /* USE_PIPES */
490:
491: /* Do processing for the child (exec command etc). */
1.60 markus 492: do_child(s, command);
1.1 markus 493: /* NOTREACHED */
494: }
495: if (pid < 0)
496: packet_disconnect("fork failed: %.100s", strerror(errno));
497: s->pid = pid;
1.47 markus 498: /* Set interactive/non-interactive mode. */
1.48 markus 499: packet_set_interactive(s->display != NULL);
1.1 markus 500: #ifdef USE_PIPES
501: /* We are the parent. Close the child sides of the pipes. */
502: close(pin[0]);
503: close(pout[1]);
504: close(perr[1]);
505:
1.2 markus 506: if (compat20) {
1.64 markus 507: session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
1.2 markus 508: } else {
509: /* Enter the interactive session. */
510: server_loop(pid, pin[1], pout[0], perr[0]);
1.64 markus 511: /* server_loop has closed pin[1], pout[0], and perr[0]. */
1.2 markus 512: }
1.1 markus 513: #else /* USE_PIPES */
514: /* We are the parent. Close the child sides of the socket pairs. */
515: close(inout[0]);
516: close(err[0]);
517:
518: /*
519: * Enter the interactive session. Note: server_loop must be able to
520: * handle the case that fdin and fdout are the same.
521: */
1.2 markus 522: if (compat20) {
1.64 markus 523: session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
1.2 markus 524: } else {
525: server_loop(pid, inout[1], inout[1], err[1]);
526: /* server_loop has closed inout[1] and err[1]. */
527: }
1.1 markus 528: #endif /* USE_PIPES */
529: }
530:
531: /*
532: * This is called to fork and execute a command when we have a tty. This
533: * will call do_child from the child, and server_loop from the parent after
534: * setting up file descriptors, controlling tty, updating wtmp, utmp,
535: * lastlog, and other such operations.
536: */
1.4 markus 537: void
1.63 markus 538: do_exec_pty(Session *s, const char *command)
1.1 markus 539: {
540: int fdout, ptyfd, ttyfd, ptymaster;
541: pid_t pid;
542:
543: if (s == NULL)
544: fatal("do_exec_pty: no session");
545: ptyfd = s->ptyfd;
546: ttyfd = s->ttyfd;
547:
548: /* Fork the child. */
549: if ((pid = fork()) == 0) {
1.97 markus 550:
1.24 markus 551: /* Child. Reinitialize the log because the pid has changed. */
1.1 markus 552: log_init(__progname, options.log_level, options.log_facility, log_stderr);
553: /* Close the master side of the pseudo tty. */
554: close(ptyfd);
555:
556: /* Make the pseudo tty our controlling tty. */
557: pty_make_controlling_tty(&ttyfd, s->tty);
558:
1.103 markus 559: /* Redirect stdin/stdout/stderr from the pseudo tty. */
560: if (dup2(ttyfd, 0) < 0)
561: error("dup2 stdin: %s", strerror(errno));
562: if (dup2(ttyfd, 1) < 0)
563: error("dup2 stdout: %s", strerror(errno));
564: if (dup2(ttyfd, 2) < 0)
565: error("dup2 stderr: %s", strerror(errno));
1.1 markus 566:
567: /* Close the extra descriptor for the pseudo tty. */
568: close(ttyfd);
569:
1.24 markus 570: /* record login, etc. similar to login(1) */
1.41 markus 571: if (!(options.use_login && command == NULL))
572: do_login(s, command);
1.1 markus 573:
574: /* Do common processing for the child, such as execing the command. */
1.60 markus 575: do_child(s, command);
1.1 markus 576: /* NOTREACHED */
577: }
578: if (pid < 0)
579: packet_disconnect("fork failed: %.100s", strerror(errno));
580: s->pid = pid;
581:
582: /* Parent. Close the slave side of the pseudo tty. */
583: close(ttyfd);
584:
585: /*
586: * Create another descriptor of the pty master side for use as the
587: * standard input. We could use the original descriptor, but this
588: * simplifies code in server_loop. The descriptor is bidirectional.
589: */
590: fdout = dup(ptyfd);
591: if (fdout < 0)
592: packet_disconnect("dup #1 failed: %.100s", strerror(errno));
593:
594: /* we keep a reference to the pty master */
595: ptymaster = dup(ptyfd);
596: if (ptymaster < 0)
597: packet_disconnect("dup #2 failed: %.100s", strerror(errno));
598: s->ptymaster = ptymaster;
599:
600: /* Enter interactive session. */
1.47 markus 601: packet_set_interactive(1);
1.2 markus 602: if (compat20) {
603: session_set_fds(s, ptyfd, fdout, -1);
604: } else {
605: server_loop(pid, ptyfd, fdout, -1);
606: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 607: }
608: }
609:
1.90 markus 610: /*
611: * This is called to fork and execute a command. If another command is
612: * to be forced, execute that instead.
613: */
614: void
615: do_exec(Session *s, const char *command)
616: {
617: if (forced_command) {
618: original_command = command;
619: command = forced_command;
620: debug("Forced command '%.900s'", command);
621: }
622:
623: if (s->ttyfd != -1)
624: do_exec_pty(s, command);
625: else
626: do_exec_no_pty(s, command);
627:
1.92 markus 628: original_command = NULL;
1.90 markus 629: }
630:
631:
1.24 markus 632: /* administrative, login(1)-like work */
633: void
1.41 markus 634: do_login(Session *s, const char *command)
1.24 markus 635: {
636: char *time_string;
637: socklen_t fromlen;
638: struct sockaddr_storage from;
639: struct passwd * pw = s->pw;
640: pid_t pid = getpid();
641:
642: /*
643: * Get IP address of client. If the connection is not a socket, let
644: * the address be 0.0.0.0.
645: */
646: memset(&from, 0, sizeof(from));
647: if (packet_connection_is_on_socket()) {
648: fromlen = sizeof(from);
649: if (getpeername(packet_get_connection_in(),
1.112 deraadt 650: (struct sockaddr *) & from, &fromlen) < 0) {
1.24 markus 651: debug("getpeername: %.100s", strerror(errno));
652: fatal_cleanup();
653: }
654: }
1.25 markus 655:
1.24 markus 656: /* Record that there was a login on that tty from the remote host. */
1.133 markus 657: if (!use_privsep)
658: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
659: get_remote_name_or_ip(utmp_len,
660: options.verify_reverse_mapping),
661: (struct sockaddr *)&from);
1.24 markus 662:
1.73 djm 663: if (check_quietlogin(s, command))
1.24 markus 664: return;
1.73 djm 665:
1.134 markus 666: if (options.print_lastlog && s->last_login_time != 0) {
667: time_string = ctime(&s->last_login_time);
1.24 markus 668: if (strchr(time_string, '\n'))
669: *strchr(time_string, '\n') = 0;
1.134 markus 670: if (strcmp(s->hostname, "") == 0)
1.24 markus 671: printf("Last login: %s\r\n", time_string);
672: else
1.134 markus 673: printf("Last login: %s from %s\r\n", time_string,
674: s->hostname);
1.24 markus 675: }
1.73 djm 676:
677: do_motd();
678: }
679:
680: /*
681: * Display the message of the day.
682: */
683: void
684: do_motd(void)
685: {
686: FILE *f;
687: char buf[256];
688:
1.24 markus 689: if (options.print_motd) {
1.28 millert 690: #ifdef HAVE_LOGIN_CAP
691: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
692: "/etc/motd"), "r");
693: #else
1.24 markus 694: f = fopen("/etc/motd", "r");
1.28 millert 695: #endif
1.24 markus 696: if (f) {
697: while (fgets(buf, sizeof(buf), f))
698: fputs(buf, stdout);
699: fclose(f);
700: }
1.2 markus 701: }
1.73 djm 702: }
703:
704:
705: /*
706: * Check for quiet login, either .hushlogin or command given.
707: */
708: int
709: check_quietlogin(Session *s, const char *command)
710: {
711: char buf[256];
1.96 dugsong 712: struct passwd *pw = s->pw;
1.73 djm 713: struct stat st;
714:
715: /* Return 1 if .hushlogin exists or a command given. */
716: if (command != NULL)
717: return 1;
718: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
719: #ifdef HAVE_LOGIN_CAP
720: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
721: return 1;
722: #else
723: if (stat(buf, &st) >= 0)
724: return 1;
725: #endif
726: return 0;
1.1 markus 727: }
728:
729: /*
730: * Sets the value of the given variable in the environment. If the variable
731: * already exists, its value is overriden.
732: */
1.94 itojun 733: static void
1.45 markus 734: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 735: const char *value)
1.1 markus 736: {
1.45 markus 737: u_int i, namelen;
1.1 markus 738: char **env;
739:
740: /*
741: * Find the slot where the value should be stored. If the variable
742: * already exists, we reuse the slot; otherwise we append a new slot
743: * at the end of the array, expanding if necessary.
744: */
745: env = *envp;
746: namelen = strlen(name);
747: for (i = 0; env[i]; i++)
748: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
749: break;
750: if (env[i]) {
751: /* Reuse the slot. */
752: xfree(env[i]);
753: } else {
754: /* New variable. Expand if necessary. */
755: if (i >= (*envsizep) - 1) {
1.141 markus 756: if (*envsizep >= 1000)
757: fatal("child_set_env: too many env vars,"
758: " skipping: %.100s", name);
1.1 markus 759: (*envsizep) += 50;
760: env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
761: }
762: /* Need to set the NULL pointer at end of array beyond the new slot. */
763: env[i + 1] = NULL;
764: }
765:
766: /* Allocate space and format the variable in the appropriate slot. */
767: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
768: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
769: }
770:
771: /*
772: * Reads environment variables from the given file and adds/overrides them
773: * into the environment. If the file does not exist, this does nothing.
774: * Otherwise, it must consist of empty lines, comments (line starts with '#')
775: * and assignments of the form name=value. No other forms are allowed.
776: */
1.94 itojun 777: static void
1.45 markus 778: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 779: const char *filename)
1.1 markus 780: {
781: FILE *f;
782: char buf[4096];
783: char *cp, *value;
1.142 ! deraadt 784: u_int lineno = 0;
1.1 markus 785:
786: f = fopen(filename, "r");
787: if (!f)
788: return;
789:
790: while (fgets(buf, sizeof(buf), f)) {
1.142 ! deraadt 791: if (++lineno > 1000)
! 792: fatal("Too many lines in environment file %s", filename);
1.1 markus 793: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
794: ;
795: if (!*cp || *cp == '#' || *cp == '\n')
796: continue;
797: if (strchr(cp, '\n'))
798: *strchr(cp, '\n') = '\0';
799: value = strchr(cp, '=');
800: if (value == NULL) {
1.142 ! deraadt 801: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
! 802: filename);
1.1 markus 803: continue;
804: }
1.14 deraadt 805: /*
806: * Replace the equals sign by nul, and advance value to
807: * the value string.
808: */
1.1 markus 809: *value = '\0';
810: value++;
811: child_set_env(env, envsize, cp, value);
812: }
813: fclose(f);
814: }
815:
1.127 markus 816: static char **
817: do_setup_env(Session *s, const char *shell)
1.1 markus 818: {
819: char buf[256];
1.127 markus 820: u_int i, envsize;
1.1 markus 821: char **env;
1.127 markus 822: struct passwd *pw = s->pw;
1.1 markus 823:
824: /* Initialize the environment. */
825: envsize = 100;
826: env = xmalloc(envsize * sizeof(char *));
827: env[0] = NULL;
828:
829: if (!options.use_login) {
830: /* Set basic environment. */
831: child_set_env(&env, &envsize, "USER", pw->pw_name);
832: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
833: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.28 millert 834: #ifdef HAVE_LOGIN_CAP
1.29 millert 835: (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
836: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.28 millert 837: #else
1.29 millert 838: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1.28 millert 839: #endif
1.1 markus 840:
841: snprintf(buf, sizeof buf, "%.200s/%.50s",
842: _PATH_MAILDIR, pw->pw_name);
843: child_set_env(&env, &envsize, "MAIL", buf);
844:
845: /* Normal systems set SHELL by default. */
846: child_set_env(&env, &envsize, "SHELL", shell);
847: }
848: if (getenv("TZ"))
849: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
850:
851: /* Set custom environment options from RSA authentication. */
1.110 markus 852: if (!options.use_login) {
853: while (custom_environment) {
854: struct envstring *ce = custom_environment;
855: char *s = ce->s;
1.127 markus 856:
1.110 markus 857: for (i = 0; s[i] != '=' && s[i]; i++)
858: ;
859: if (s[i] == '=') {
860: s[i] = 0;
861: child_set_env(&env, &envsize, s, s + i + 1);
862: }
863: custom_environment = ce->next;
864: xfree(ce->s);
865: xfree(ce);
1.1 markus 866: }
867: }
868:
869: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 870: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 871: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
872:
1.60 markus 873: if (s->ttyfd != -1)
874: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
875: if (s->term)
876: child_set_env(&env, &envsize, "TERM", s->term);
877: if (s->display)
878: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 879: if (original_command)
880: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
881: original_command);
1.1 markus 882: #ifdef KRB4
1.96 dugsong 883: if (s->authctxt->krb4_ticket_file)
884: child_set_env(&env, &envsize, "KRBTKFILE",
1.112 deraadt 885: s->authctxt->krb4_ticket_file);
1.96 dugsong 886: #endif
887: #ifdef KRB5
888: if (s->authctxt->krb5_ticket_file)
889: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 890: s->authctxt->krb5_ticket_file);
1.96 dugsong 891: #endif
1.136 markus 892: if (auth_sock_name != NULL)
1.1 markus 893: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 894: auth_sock_name);
1.1 markus 895:
896: /* read $HOME/.ssh/environment. */
897: if (!options.use_login) {
1.14 deraadt 898: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
899: pw->pw_dir);
1.1 markus 900: read_environment_file(&env, &envsize, buf);
901: }
902: if (debug_flag) {
903: /* dump the environment */
904: fprintf(stderr, "Environment:\n");
905: for (i = 0; env[i]; i++)
906: fprintf(stderr, " %.200s\n", env[i]);
907: }
1.127 markus 908: return env;
909: }
910:
911: /*
912: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
913: * first in this order).
914: */
915: static void
916: do_rc_files(Session *s, const char *shell)
917: {
918: FILE *f = NULL;
919: char cmd[1024];
920: int do_xauth;
921: struct stat st;
922:
923: do_xauth =
924: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
925:
926: /* ignore _PATH_SSH_USER_RC for subsystems */
927: if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
928: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
929: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
930: if (debug_flag)
931: fprintf(stderr, "Running %s\n", cmd);
932: f = popen(cmd, "w");
933: if (f) {
934: if (do_xauth)
935: fprintf(f, "%s %s\n", s->auth_proto,
936: s->auth_data);
937: pclose(f);
938: } else
939: fprintf(stderr, "Could not run %s\n",
940: _PATH_SSH_USER_RC);
941: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
942: if (debug_flag)
943: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
944: _PATH_SSH_SYSTEM_RC);
945: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
946: if (f) {
947: if (do_xauth)
948: fprintf(f, "%s %s\n", s->auth_proto,
949: s->auth_data);
950: pclose(f);
951: } else
952: fprintf(stderr, "Could not run %s\n",
953: _PATH_SSH_SYSTEM_RC);
954: } else if (do_xauth && options.xauth_location != NULL) {
955: /* Add authority data to .Xauthority if appropriate. */
956: if (debug_flag) {
957: fprintf(stderr,
1.135 stevesk 958: "Running %.500s add "
1.127 markus 959: "%.100s %.100s %.100s\n",
960: options.xauth_location, s->auth_display,
961: s->auth_proto, s->auth_data);
962: }
963: snprintf(cmd, sizeof cmd, "%s -q -",
964: options.xauth_location);
965: f = popen(cmd, "w");
966: if (f) {
967: fprintf(f, "add %s %s %s\n",
968: s->auth_display, s->auth_proto,
969: s->auth_data);
970: pclose(f);
971: } else {
972: fprintf(stderr, "Could not run %s\n",
973: cmd);
974: }
975: }
976: }
977:
978: static void
979: do_nologin(struct passwd *pw)
980: {
981: FILE *f = NULL;
982: char buf[1024];
983:
984: #ifdef HAVE_LOGIN_CAP
985: if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
986: f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
987: _PATH_NOLOGIN), "r");
988: #else
989: if (pw->pw_uid)
990: f = fopen(_PATH_NOLOGIN, "r");
991: #endif
992: if (f) {
993: /* /etc/nologin exists. Print its contents and exit. */
994: while (fgets(buf, sizeof(buf), f))
995: fputs(buf, stderr);
996: fclose(f);
997: exit(254);
998: }
999: }
1000:
1001: /* Set login name, uid, gid, and groups. */
1.130 provos 1002: void
1.127 markus 1003: do_setusercontext(struct passwd *pw)
1004: {
1005: if (getuid() == 0 || geteuid() == 0) {
1006: #ifdef HAVE_LOGIN_CAP
1007: if (setusercontext(lc, pw, pw->pw_uid,
1008: (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1009: perror("unable to set user context");
1010: exit(1);
1011: }
1012: #else
1013: if (setlogin(pw->pw_name) < 0)
1014: error("setlogin failed: %s", strerror(errno));
1015: if (setgid(pw->pw_gid) < 0) {
1016: perror("setgid");
1017: exit(1);
1018: }
1019: /* Initialize the group list. */
1020: if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1021: perror("initgroups");
1022: exit(1);
1023: }
1024: endgrent();
1025:
1026: /* Permanently switch to the desired uid. */
1027: permanently_set_uid(pw);
1028: #endif
1029: }
1030: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1031: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1032: }
1033:
1.131 markus 1034: static void
1.130 provos 1035: launch_login(struct passwd *pw, const char *hostname)
1036: {
1037: /* Launch login(1). */
1038:
1039: execl("/usr/bin/login", "login", "-h", hostname,
1040: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1041:
1042: /* Login couldn't be executed, die. */
1043:
1044: perror("login");
1045: exit(1);
1046: }
1047:
1.127 markus 1048: /*
1049: * Performs common processing for the child, such as setting up the
1050: * environment, closing extra file descriptors, setting the user and group
1051: * ids, and executing the command or shell.
1052: */
1053: void
1054: do_child(Session *s, const char *command)
1055: {
1056: extern char **environ;
1057: char **env;
1058: char *argv[10];
1059: const char *shell, *shell0, *hostname = NULL;
1060: struct passwd *pw = s->pw;
1061: u_int i;
1062:
1063: /* remove hostkey from the child's memory */
1064: destroy_sensitive_data();
1065:
1066: /* login(1) is only called if we execute the login shell */
1067: if (options.use_login && command != NULL)
1068: options.use_login = 0;
1069:
1070: /*
1071: * Login(1) does this as well, and it needs uid 0 for the "-h"
1072: * switch, so we let login(1) to this for us.
1073: */
1074: if (!options.use_login) {
1075: do_nologin(pw);
1076: do_setusercontext(pw);
1077: }
1078:
1079: /*
1080: * Get the shell from the password data. An empty shell field is
1081: * legal, and means /bin/sh.
1082: */
1083: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1084: #ifdef HAVE_LOGIN_CAP
1085: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1086: #endif
1087:
1088: env = do_setup_env(s, shell);
1089:
1.26 millert 1090: /* we have to stash the hostname before we close our socket. */
1091: if (options.use_login)
1.70 stevesk 1092: hostname = get_remote_name_or_ip(utmp_len,
1.120 markus 1093: options.verify_reverse_mapping);
1.1 markus 1094: /*
1095: * Close the connection descriptors; note that this is the child, and
1096: * the server will still have the socket open, and it is important
1097: * that we do not shutdown it. Note that the descriptors cannot be
1098: * closed before building the environment, as we call
1099: * get_remote_ipaddr there.
1100: */
1101: if (packet_get_connection_in() == packet_get_connection_out())
1102: close(packet_get_connection_in());
1103: else {
1104: close(packet_get_connection_in());
1105: close(packet_get_connection_out());
1106: }
1107: /*
1108: * Close all descriptors related to channels. They will still remain
1109: * open in the parent.
1110: */
1111: /* XXX better use close-on-exec? -markus */
1112: channel_close_all();
1113:
1114: /*
1115: * Close any extra file descriptors. Note that there may still be
1116: * descriptors left by system functions. They will be closed later.
1117: */
1118: endpwent();
1119:
1120: /*
1121: * Close any extra open file descriptors so that we don\'t have them
1122: * hanging around in clients. Note that we want to do this after
1123: * initgroups, because at least on Solaris 2.3 it leaves file
1124: * descriptors open.
1125: */
1126: for (i = 3; i < 64; i++)
1127: close(i);
1128:
1129: /*
1.125 deraadt 1130: * Must take new environment into use so that .ssh/rc,
1131: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1132: */
1133: environ = env;
1.102 markus 1134:
1135: #ifdef AFS
1136: /* Try to get AFS tokens for the local cell. */
1137: if (k_hasafs()) {
1138: char cell[64];
1.112 deraadt 1139:
1.102 markus 1140: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1141: krb_afslog(cell, 0);
1.112 deraadt 1142:
1.102 markus 1143: krb_afslog(0, 0);
1144: }
1145: #endif /* AFS */
1.104 markus 1146:
1147: /* Change current directory to the user\'s home directory. */
1148: if (chdir(pw->pw_dir) < 0) {
1149: fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1150: pw->pw_dir, strerror(errno));
1151: #ifdef HAVE_LOGIN_CAP
1152: if (login_getcapbool(lc, "requirehome", 0))
1153: exit(1);
1154: #endif
1155: }
1.1 markus 1156:
1.127 markus 1157: if (!options.use_login)
1158: do_rc_files(s, shell);
1.67 markus 1159:
1160: /* restore SIGPIPE for child */
1161: signal(SIGPIPE, SIG_DFL);
1162:
1.127 markus 1163: if (options.use_login) {
1.130 provos 1164: launch_login(pw, hostname);
1165: /* NEVERREACHED */
1.127 markus 1166: }
1167:
1168: /* Get the last component of the shell name. */
1169: if ((shell0 = strrchr(shell, '/')) != NULL)
1170: shell0++;
1171: else
1172: shell0 = shell;
1173:
1.1 markus 1174: /*
1175: * If we have no command, execute the shell. In this case, the shell
1176: * name to be passed in argv[0] is preceded by '-' to indicate that
1177: * this is a login shell.
1178: */
1179: if (!command) {
1.127 markus 1180: char argv0[256];
1.1 markus 1181:
1.127 markus 1182: /* Start the shell. Set initial character to '-'. */
1183: argv0[0] = '-';
1.1 markus 1184:
1.127 markus 1185: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1186: >= sizeof(argv0) - 1) {
1.127 markus 1187: errno = EINVAL;
1.1 markus 1188: perror(shell);
1189: exit(1);
1.127 markus 1190: }
1.1 markus 1191:
1.127 markus 1192: /* Execute the shell. */
1193: argv[0] = argv0;
1194: argv[1] = NULL;
1195: execve(shell, argv, env);
1196:
1197: /* Executing the shell failed. */
1198: perror(shell);
1199: exit(1);
1.1 markus 1200: }
1201: /*
1202: * Execute the command using the user's shell. This uses the -c
1203: * option to execute the command.
1204: */
1.127 markus 1205: argv[0] = (char *) shell0;
1.1 markus 1206: argv[1] = "-c";
1207: argv[2] = (char *) command;
1208: argv[3] = NULL;
1209: execve(shell, argv, env);
1210: perror(shell);
1211: exit(1);
1212: }
1213:
1214: Session *
1215: session_new(void)
1216: {
1217: int i;
1218: static int did_init = 0;
1219: if (!did_init) {
1220: debug("session_new: init");
1.112 deraadt 1221: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1222: sessions[i].used = 0;
1223: }
1224: did_init = 1;
1225: }
1.112 deraadt 1226: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1227: Session *s = &sessions[i];
1228: if (! s->used) {
1.68 djm 1229: memset(s, 0, sizeof(*s));
1.1 markus 1230: s->chanid = -1;
1231: s->ptyfd = -1;
1232: s->ttyfd = -1;
1233: s->used = 1;
1.85 markus 1234: s->self = i;
1.1 markus 1235: debug("session_new: session %d", i);
1236: return s;
1237: }
1238: }
1239: return NULL;
1240: }
1241:
1.94 itojun 1242: static void
1.1 markus 1243: session_dump(void)
1244: {
1245: int i;
1.112 deraadt 1246: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1247: Session *s = &sessions[i];
1.137 mpech 1248: debug("dump: used %d session %d %p channel %d pid %ld",
1.1 markus 1249: s->used,
1250: s->self,
1251: s,
1252: s->chanid,
1.137 mpech 1253: (long)s->pid);
1.1 markus 1254: }
1255: }
1256:
1.2 markus 1257: int
1.97 markus 1258: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1259: {
1260: Session *s = session_new();
1261: debug("session_open: channel %d", chanid);
1262: if (s == NULL) {
1263: error("no more sessions");
1264: return 0;
1265: }
1.97 markus 1266: s->authctxt = authctxt;
1267: s->pw = authctxt->pw;
1.7 markus 1268: if (s->pw == NULL)
1.54 stevesk 1269: fatal("no user for session %d", s->self);
1.2 markus 1270: debug("session_open: session %d: link with channel %d", s->self, chanid);
1271: s->chanid = chanid;
1272: return 1;
1273: }
1274:
1.130 provos 1275: Session *
1276: session_by_tty(char *tty)
1277: {
1278: int i;
1279: for (i = 0; i < MAX_SESSIONS; i++) {
1280: Session *s = &sessions[i];
1281: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1282: debug("session_by_tty: session %d tty %s", i, tty);
1283: return s;
1284: }
1285: }
1286: debug("session_by_tty: unknown tty %.100s", tty);
1287: session_dump();
1288: return NULL;
1289: }
1290:
1.94 itojun 1291: static Session *
1.2 markus 1292: session_by_channel(int id)
1293: {
1294: int i;
1.112 deraadt 1295: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1296: Session *s = &sessions[i];
1297: if (s->used && s->chanid == id) {
1298: debug("session_by_channel: session %d channel %d", i, id);
1299: return s;
1300: }
1301: }
1302: debug("session_by_channel: unknown channel %d", id);
1303: session_dump();
1304: return NULL;
1305: }
1306:
1.94 itojun 1307: static Session *
1.2 markus 1308: session_by_pid(pid_t pid)
1309: {
1310: int i;
1.137 mpech 1311: debug("session_by_pid: pid %ld", (long)pid);
1.112 deraadt 1312: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1313: Session *s = &sessions[i];
1314: if (s->used && s->pid == pid)
1315: return s;
1316: }
1.137 mpech 1317: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1318: session_dump();
1319: return NULL;
1320: }
1321:
1.94 itojun 1322: static int
1.2 markus 1323: session_window_change_req(Session *s)
1324: {
1325: s->col = packet_get_int();
1326: s->row = packet_get_int();
1327: s->xpixel = packet_get_int();
1328: s->ypixel = packet_get_int();
1.116 markus 1329: packet_check_eom();
1.2 markus 1330: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1331: return 1;
1332: }
1333:
1.94 itojun 1334: static int
1.2 markus 1335: session_pty_req(Session *s)
1336: {
1.45 markus 1337: u_int len;
1.72 stevesk 1338: int n_bytes;
1.132 markus 1339:
1.86 markus 1340: if (no_pty_flag) {
1341: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1342: return 0;
1.86 markus 1343: }
1344: if (s->ttyfd != -1) {
1345: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1346: return 0;
1.134 markus 1347: }
1348: /* Get the time and hostname when the user last logged in. */
1349: if (options.print_lastlog) {
1350: s->hostname[0] = '\0';
1351: s->last_login_time = get_last_login_time(s->pw->pw_uid,
1352: s->pw->pw_name, s->hostname, sizeof(s->hostname));
1.86 markus 1353: }
1354:
1.2 markus 1355: s->term = packet_get_string(&len);
1.86 markus 1356:
1357: if (compat20) {
1358: s->col = packet_get_int();
1359: s->row = packet_get_int();
1360: } else {
1361: s->row = packet_get_int();
1362: s->col = packet_get_int();
1363: }
1.2 markus 1364: s->xpixel = packet_get_int();
1365: s->ypixel = packet_get_int();
1366:
1367: if (strcmp(s->term, "") == 0) {
1368: xfree(s->term);
1369: s->term = NULL;
1370: }
1.86 markus 1371:
1.2 markus 1372: /* Allocate a pty and open it. */
1.86 markus 1373: debug("Allocating pty.");
1.130 provos 1374: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1.86 markus 1375: if (s->term)
1376: xfree(s->term);
1.2 markus 1377: s->term = NULL;
1378: s->ptyfd = -1;
1379: s->ttyfd = -1;
1380: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1381: return 0;
1.2 markus 1382: }
1383: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1384:
1385: /* for SSH1 the tty modes length is not given */
1386: if (!compat20)
1387: n_bytes = packet_remaining();
1388: tty_parse_modes(s->ttyfd, &n_bytes);
1389:
1.2 markus 1390: /*
1391: * Add a cleanup function to clear the utmp entry and record logout
1392: * time in case we call fatal() (e.g., the connection gets closed).
1393: */
1.85 markus 1394: fatal_add_cleanup(session_pty_cleanup, (void *)s);
1.130 provos 1395: if (!use_privsep)
1396: pty_setowner(s->pw, s->tty);
1.86 markus 1397:
1398: /* Set window size from the packet. */
1.2 markus 1399: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1400:
1.116 markus 1401: packet_check_eom();
1.9 markus 1402: session_proctitle(s);
1.2 markus 1403: return 1;
1404: }
1405:
1.94 itojun 1406: static int
1.7 markus 1407: session_subsystem_req(Session *s)
1408: {
1.105 markus 1409: struct stat st;
1.45 markus 1410: u_int len;
1.7 markus 1411: int success = 0;
1.105 markus 1412: char *cmd, *subsys = packet_get_string(&len);
1.18 jakob 1413: int i;
1.7 markus 1414:
1.116 markus 1415: packet_check_eom();
1.121 stevesk 1416: log("subsystem request for %.100s", subsys);
1.18 jakob 1417:
1418: for (i = 0; i < options.num_subsystems; i++) {
1.105 markus 1419: if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1420: cmd = options.subsystem_command[i];
1421: if (stat(cmd, &st) < 0) {
1422: error("subsystem: cannot stat %s: %s", cmd,
1423: strerror(errno));
1424: break;
1425: }
1426: debug("subsystem: exec() %s", cmd);
1.64 markus 1427: s->is_subsystem = 1;
1.105 markus 1428: do_exec(s, cmd);
1.18 jakob 1429: success = 1;
1.122 markus 1430: break;
1.18 jakob 1431: }
1432: }
1433:
1434: if (!success)
1.121 stevesk 1435: log("subsystem request for %.100s failed, subsystem not found",
1.105 markus 1436: subsys);
1.7 markus 1437:
1438: xfree(subsys);
1439: return success;
1440: }
1441:
1.94 itojun 1442: static int
1.7 markus 1443: session_x11_req(Session *s)
1444: {
1.81 markus 1445: int success;
1.7 markus 1446:
1447: s->single_connection = packet_get_char();
1448: s->auth_proto = packet_get_string(NULL);
1449: s->auth_data = packet_get_string(NULL);
1450: s->screen = packet_get_int();
1.116 markus 1451: packet_check_eom();
1.7 markus 1452:
1.81 markus 1453: success = session_setup_x11fwd(s);
1454: if (!success) {
1.7 markus 1455: xfree(s->auth_proto);
1456: xfree(s->auth_data);
1.84 markus 1457: s->auth_proto = NULL;
1458: s->auth_data = NULL;
1.7 markus 1459: }
1.81 markus 1460: return success;
1.7 markus 1461: }
1462:
1.94 itojun 1463: static int
1.19 markus 1464: session_shell_req(Session *s)
1465: {
1.116 markus 1466: packet_check_eom();
1.90 markus 1467: do_exec(s, NULL);
1.19 markus 1468: return 1;
1469: }
1470:
1.94 itojun 1471: static int
1.19 markus 1472: session_exec_req(Session *s)
1473: {
1.45 markus 1474: u_int len;
1.19 markus 1475: char *command = packet_get_string(&len);
1.116 markus 1476: packet_check_eom();
1.90 markus 1477: do_exec(s, command);
1.92 markus 1478: xfree(command);
1.19 markus 1479: return 1;
1480: }
1481:
1.94 itojun 1482: static int
1.43 markus 1483: session_auth_agent_req(Session *s)
1484: {
1485: static int called = 0;
1.116 markus 1486: packet_check_eom();
1.44 markus 1487: if (no_agent_forwarding_flag) {
1488: debug("session_auth_agent_req: no_agent_forwarding_flag");
1489: return 0;
1490: }
1.43 markus 1491: if (called) {
1492: return 0;
1493: } else {
1494: called = 1;
1495: return auth_input_request_forwarding(s->pw);
1496: }
1497: }
1498:
1.123 markus 1499: int
1500: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1501: {
1502: int success = 0;
1503: Session *s;
1504:
1.123 markus 1505: if ((s = session_by_channel(c->self)) == NULL) {
1506: log("session_input_channel_req: no session %d req %.100s",
1507: c->self, rtype);
1508: return 0;
1509: }
1510: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1511:
1512: /*
1.64 markus 1513: * a session is in LARVAL state until a shell, a command
1514: * or a subsystem is executed
1.2 markus 1515: */
1516: if (c->type == SSH_CHANNEL_LARVAL) {
1517: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1518: success = session_shell_req(s);
1.2 markus 1519: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1520: success = session_exec_req(s);
1.2 markus 1521: } else if (strcmp(rtype, "pty-req") == 0) {
1.3 markus 1522: success = session_pty_req(s);
1.7 markus 1523: } else if (strcmp(rtype, "x11-req") == 0) {
1524: success = session_x11_req(s);
1.43 markus 1525: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1526: success = session_auth_agent_req(s);
1.7 markus 1527: } else if (strcmp(rtype, "subsystem") == 0) {
1528: success = session_subsystem_req(s);
1.2 markus 1529: }
1530: }
1531: if (strcmp(rtype, "window-change") == 0) {
1532: success = session_window_change_req(s);
1533: }
1.123 markus 1534: return success;
1.2 markus 1535: }
1536:
1537: void
1538: session_set_fds(Session *s, int fdin, int fdout, int fderr)
1539: {
1540: if (!compat20)
1541: fatal("session_set_fds: called for proto != 2.0");
1542: /*
1543: * now that have a child and a pipe to the child,
1544: * we can activate our channel and register the fd's
1545: */
1546: if (s->chanid == -1)
1547: fatal("no channel for session %d", s->self);
1548: channel_set_fds(s->chanid,
1549: fdout, fdin, fderr,
1.42 markus 1550: fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.126 markus 1551: 1,
1552: CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1553: }
1554:
1.85 markus 1555: /*
1556: * Function to perform pty cleanup. Also called if we get aborted abnormally
1557: * (e.g., due to a dropped connection).
1558: */
1.130 provos 1559: void
1560: session_pty_cleanup2(void *session)
1.1 markus 1561: {
1.85 markus 1562: Session *s = session;
1563:
1564: if (s == NULL) {
1565: error("session_pty_cleanup: no session");
1566: return;
1567: }
1568: if (s->ttyfd == -1)
1.1 markus 1569: return;
1570:
1.54 stevesk 1571: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1572:
1573: /* Record that the user has logged out. */
1.85 markus 1574: if (s->pid != 0)
1575: record_logout(s->pid, s->tty);
1.1 markus 1576:
1577: /* Release the pseudo-tty. */
1.130 provos 1578: if (getuid() == 0)
1579: pty_release(s->tty);
1.1 markus 1580:
1581: /*
1582: * Close the server side of the socket pairs. We must do this after
1583: * the pty cleanup, so that another process doesn't get this pty
1584: * while we're still cleaning up.
1585: */
1586: if (close(s->ptymaster) < 0)
1.130 provos 1587: error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1.108 markus 1588:
1589: /* unlink pty from session */
1590: s->ttyfd = -1;
1.2 markus 1591: }
1592:
1.130 provos 1593: void
1594: session_pty_cleanup(void *session)
1595: {
1596: PRIVSEP(session_pty_cleanup2(session));
1597: }
1598:
1.94 itojun 1599: static void
1.2 markus 1600: session_exit_message(Session *s, int status)
1601: {
1602: Channel *c;
1.124 markus 1603:
1604: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 1605: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 1606: s->self, s->chanid);
1.137 mpech 1607: debug("session_exit_message: session %d channel %d pid %ld",
1608: s->self, s->chanid, (long)s->pid);
1.2 markus 1609:
1610: if (WIFEXITED(status)) {
1.124 markus 1611: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 1612: packet_put_int(WEXITSTATUS(status));
1613: packet_send();
1614: } else if (WIFSIGNALED(status)) {
1.124 markus 1615: channel_request_start(s->chanid, "exit-signal", 0);
1.2 markus 1616: packet_put_int(WTERMSIG(status));
1617: packet_put_char(WCOREDUMP(status));
1618: packet_put_cstring("");
1619: packet_put_cstring("");
1620: packet_send();
1621: } else {
1622: /* Some weird exit cause. Just exit. */
1623: packet_disconnect("wait returned status %04x.", status);
1624: }
1625:
1626: /* disconnect channel */
1627: debug("session_exit_message: release channel %d", s->chanid);
1628: channel_cancel_cleanup(s->chanid);
1.5 markus 1629: /*
1630: * emulate a write failure with 'chan_write_failed', nobody will be
1631: * interested in data we write.
1632: * Note that we must not call 'chan_read_failed', since there could
1633: * be some more data waiting in the pipe.
1634: */
1.8 markus 1635: if (c->ostate != CHAN_OUTPUT_CLOSED)
1636: chan_write_failed(c);
1.2 markus 1637: s->chanid = -1;
1638: }
1639:
1.130 provos 1640: void
1.85 markus 1641: session_close(Session *s)
1.2 markus 1642: {
1.137 mpech 1643: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.85 markus 1644: if (s->ttyfd != -1) {
1645: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1646: session_pty_cleanup(s);
1647: }
1.2 markus 1648: if (s->term)
1649: xfree(s->term);
1650: if (s->display)
1651: xfree(s->display);
1.118 stevesk 1652: if (s->auth_display)
1653: xfree(s->auth_display);
1.2 markus 1654: if (s->auth_data)
1655: xfree(s->auth_data);
1656: if (s->auth_proto)
1657: xfree(s->auth_proto);
1658: s->used = 0;
1.9 markus 1659: session_proctitle(s);
1.2 markus 1660: }
1661:
1662: void
1663: session_close_by_pid(pid_t pid, int status)
1664: {
1665: Session *s = session_by_pid(pid);
1666: if (s == NULL) {
1.137 mpech 1667: debug("session_close_by_pid: no session for pid %ld",
1668: (long)pid);
1.2 markus 1669: return;
1670: }
1671: if (s->chanid != -1)
1672: session_exit_message(s, status);
1673: session_close(s);
1.98 markus 1674: }
1675:
1.2 markus 1676: /*
1677: * this is called when a channel dies before
1678: * the session 'child' itself dies
1679: */
1680: void
1681: session_close_by_channel(int id, void *arg)
1682: {
1683: Session *s = session_by_channel(id);
1684: if (s == NULL) {
1.107 markus 1685: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 1686: return;
1687: }
1.137 mpech 1688: debug("session_close_by_channel: channel %d child %ld",
1689: id, (long)s->pid);
1.107 markus 1690: if (s->pid != 0) {
1691: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 1692: /*
1693: * delay detach of session, but release pty, since
1694: * the fd's to the child are already closed
1695: */
1696: if (s->ttyfd != -1) {
1697: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1698: session_pty_cleanup(s);
1699: }
1.107 markus 1700: return;
1701: }
1702: /* detach by removing callback */
1.2 markus 1703: channel_cancel_cleanup(s->chanid);
1704: s->chanid = -1;
1.106 markus 1705: session_close(s);
1706: }
1707:
1708: void
1.130 provos 1709: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 1710: {
1711: int i;
1.112 deraadt 1712: for (i = 0; i < MAX_SESSIONS; i++) {
1.106 markus 1713: Session *s = &sessions[i];
1.130 provos 1714: if (s->used) {
1715: if (closefunc != NULL)
1716: closefunc(s);
1717: else
1718: session_close(s);
1719: }
1.2 markus 1720: }
1.9 markus 1721: }
1722:
1.94 itojun 1723: static char *
1.9 markus 1724: session_tty_list(void)
1725: {
1726: static char buf[1024];
1727: int i;
1728: buf[0] = '\0';
1.112 deraadt 1729: for (i = 0; i < MAX_SESSIONS; i++) {
1.9 markus 1730: Session *s = &sessions[i];
1731: if (s->used && s->ttyfd != -1) {
1732: if (buf[0] != '\0')
1733: strlcat(buf, ",", sizeof buf);
1734: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1735: }
1736: }
1737: if (buf[0] == '\0')
1738: strlcpy(buf, "notty", sizeof buf);
1739: return buf;
1740: }
1741:
1742: void
1743: session_proctitle(Session *s)
1744: {
1745: if (s->pw == NULL)
1746: error("no user for session %d", s->self);
1747: else
1748: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 1749: }
1750:
1751: int
1752: session_setup_x11fwd(Session *s)
1753: {
1754: struct stat st;
1.109 stevesk 1755: char display[512], auth_display[512];
1756: char hostname[MAXHOSTNAMELEN];
1.81 markus 1757:
1758: if (no_x11_forwarding_flag) {
1759: packet_send_debug("X11 forwarding disabled in user configuration file.");
1760: return 0;
1761: }
1762: if (!options.x11_forwarding) {
1763: debug("X11 forwarding disabled in server configuration file.");
1764: return 0;
1765: }
1766: if (!options.xauth_location ||
1767: (stat(options.xauth_location, &st) == -1)) {
1768: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 1769: return 0;
1770: }
1771: if (options.use_login) {
1772: packet_send_debug("X11 forwarding disabled; "
1773: "not compatible with UseLogin=yes.");
1.81 markus 1774: return 0;
1775: }
1.87 markus 1776: if (s->display != NULL) {
1.81 markus 1777: debug("X11 display already set.");
1778: return 0;
1779: }
1.140 deraadt 1780: if (x11_create_display_inet(options.x11_display_offset,
1781: options.x11_use_localhost, s->single_connection,
1782: &s->display_number) == -1) {
1.87 markus 1783: debug("x11_create_display_inet failed.");
1.81 markus 1784: return 0;
1785: }
1.109 stevesk 1786:
1787: /* Set up a suitable value for the DISPLAY variable. */
1788: if (gethostname(hostname, sizeof(hostname)) < 0)
1789: fatal("gethostname: %.100s", strerror(errno));
1790: /*
1791: * auth_display must be used as the displayname when the
1792: * authorization entry is added with xauth(1). This will be
1793: * different than the DISPLAY string for localhost displays.
1794: */
1.119 stevesk 1795: if (options.x11_use_localhost) {
1.140 deraadt 1796: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 1797: s->display_number, s->screen);
1.140 deraadt 1798: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 1799: s->display_number, s->screen);
1.109 stevesk 1800: s->display = xstrdup(display);
1.118 stevesk 1801: s->auth_display = xstrdup(auth_display);
1.109 stevesk 1802: } else {
1.140 deraadt 1803: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 1804: s->display_number, s->screen);
1805: s->display = xstrdup(display);
1.118 stevesk 1806: s->auth_display = xstrdup(display);
1.109 stevesk 1807: }
1808:
1.81 markus 1809: return 1;
1.2 markus 1810: }
1811:
1.94 itojun 1812: static void
1.49 markus 1813: do_authenticated2(Authctxt *authctxt)
1.2 markus 1814: {
1.97 markus 1815: server_loop2(authctxt);
1.1 markus 1816: }
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