Annotation of src/usr.bin/ssh/session.c, Revision 1.152
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"
1.152 ! markus 36: RCSID("$OpenBSD: session.c,v 1.151 2002/12/04 04:36:47 stevesk 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) {
1.144 markus 444: fatal_remove_all_cleanups();
445:
1.1 markus 446: /* Child. Reinitialize the log since the pid has changed. */
447: log_init(__progname, options.log_level, options.log_facility, log_stderr);
448:
449: /*
450: * Create a new session and process group since the 4.4BSD
451: * setlogin() affects the entire process group.
452: */
453: if (setsid() < 0)
454: error("setsid failed: %.100s", strerror(errno));
455:
456: #ifdef USE_PIPES
457: /*
458: * Redirect stdin. We close the parent side of the socket
459: * pair, and make the child side the standard input.
460: */
461: close(pin[1]);
462: if (dup2(pin[0], 0) < 0)
463: perror("dup2 stdin");
464: close(pin[0]);
465:
466: /* Redirect stdout. */
467: close(pout[0]);
468: if (dup2(pout[1], 1) < 0)
469: perror("dup2 stdout");
470: close(pout[1]);
471:
472: /* Redirect stderr. */
473: close(perr[0]);
474: if (dup2(perr[1], 2) < 0)
475: perror("dup2 stderr");
476: close(perr[1]);
477: #else /* USE_PIPES */
478: /*
479: * Redirect stdin, stdout, and stderr. Stdin and stdout will
480: * use the same socket, as some programs (particularly rdist)
481: * seem to depend on it.
482: */
483: close(inout[1]);
484: close(err[1]);
485: if (dup2(inout[0], 0) < 0) /* stdin */
486: perror("dup2 stdin");
487: if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
488: perror("dup2 stdout");
489: if (dup2(err[0], 2) < 0) /* stderr */
490: perror("dup2 stderr");
491: #endif /* USE_PIPES */
492:
493: /* Do processing for the child (exec command etc). */
1.60 markus 494: do_child(s, command);
1.1 markus 495: /* NOTREACHED */
496: }
497: if (pid < 0)
498: packet_disconnect("fork failed: %.100s", strerror(errno));
499: s->pid = pid;
1.47 markus 500: /* Set interactive/non-interactive mode. */
1.48 markus 501: packet_set_interactive(s->display != NULL);
1.1 markus 502: #ifdef USE_PIPES
503: /* We are the parent. Close the child sides of the pipes. */
504: close(pin[0]);
505: close(pout[1]);
506: close(perr[1]);
507:
1.2 markus 508: if (compat20) {
1.64 markus 509: session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
1.2 markus 510: } else {
511: /* Enter the interactive session. */
512: server_loop(pid, pin[1], pout[0], perr[0]);
1.64 markus 513: /* server_loop has closed pin[1], pout[0], and perr[0]. */
1.2 markus 514: }
1.1 markus 515: #else /* USE_PIPES */
516: /* We are the parent. Close the child sides of the socket pairs. */
517: close(inout[0]);
518: close(err[0]);
519:
520: /*
521: * Enter the interactive session. Note: server_loop must be able to
522: * handle the case that fdin and fdout are the same.
523: */
1.2 markus 524: if (compat20) {
1.64 markus 525: session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
1.2 markus 526: } else {
527: server_loop(pid, inout[1], inout[1], err[1]);
528: /* server_loop has closed inout[1] and err[1]. */
529: }
1.1 markus 530: #endif /* USE_PIPES */
531: }
532:
533: /*
534: * This is called to fork and execute a command when we have a tty. This
535: * will call do_child from the child, and server_loop from the parent after
536: * setting up file descriptors, controlling tty, updating wtmp, utmp,
537: * lastlog, and other such operations.
538: */
1.4 markus 539: void
1.63 markus 540: do_exec_pty(Session *s, const char *command)
1.1 markus 541: {
542: int fdout, ptyfd, ttyfd, ptymaster;
543: pid_t pid;
544:
545: if (s == NULL)
546: fatal("do_exec_pty: no session");
547: ptyfd = s->ptyfd;
548: ttyfd = s->ttyfd;
549:
550: /* Fork the child. */
551: if ((pid = fork()) == 0) {
1.144 markus 552: fatal_remove_all_cleanups();
1.97 markus 553:
1.24 markus 554: /* Child. Reinitialize the log because the pid has changed. */
1.1 markus 555: log_init(__progname, options.log_level, options.log_facility, log_stderr);
556: /* Close the master side of the pseudo tty. */
557: close(ptyfd);
558:
559: /* Make the pseudo tty our controlling tty. */
560: pty_make_controlling_tty(&ttyfd, s->tty);
561:
1.103 markus 562: /* Redirect stdin/stdout/stderr from the pseudo tty. */
563: if (dup2(ttyfd, 0) < 0)
564: error("dup2 stdin: %s", strerror(errno));
565: if (dup2(ttyfd, 1) < 0)
566: error("dup2 stdout: %s", strerror(errno));
567: if (dup2(ttyfd, 2) < 0)
568: error("dup2 stderr: %s", strerror(errno));
1.1 markus 569:
570: /* Close the extra descriptor for the pseudo tty. */
571: close(ttyfd);
572:
1.24 markus 573: /* record login, etc. similar to login(1) */
1.41 markus 574: if (!(options.use_login && command == NULL))
575: do_login(s, command);
1.1 markus 576:
577: /* Do common processing for the child, such as execing the command. */
1.60 markus 578: do_child(s, command);
1.1 markus 579: /* NOTREACHED */
580: }
581: if (pid < 0)
582: packet_disconnect("fork failed: %.100s", strerror(errno));
583: s->pid = pid;
584:
585: /* Parent. Close the slave side of the pseudo tty. */
586: close(ttyfd);
587:
588: /*
589: * Create another descriptor of the pty master side for use as the
590: * standard input. We could use the original descriptor, but this
591: * simplifies code in server_loop. The descriptor is bidirectional.
592: */
593: fdout = dup(ptyfd);
594: if (fdout < 0)
595: packet_disconnect("dup #1 failed: %.100s", strerror(errno));
596:
597: /* we keep a reference to the pty master */
598: ptymaster = dup(ptyfd);
599: if (ptymaster < 0)
600: packet_disconnect("dup #2 failed: %.100s", strerror(errno));
601: s->ptymaster = ptymaster;
602:
603: /* Enter interactive session. */
1.47 markus 604: packet_set_interactive(1);
1.2 markus 605: if (compat20) {
606: session_set_fds(s, ptyfd, fdout, -1);
607: } else {
608: server_loop(pid, ptyfd, fdout, -1);
609: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 610: }
611: }
612:
1.90 markus 613: /*
614: * This is called to fork and execute a command. If another command is
615: * to be forced, execute that instead.
616: */
617: void
618: do_exec(Session *s, const char *command)
619: {
620: if (forced_command) {
621: original_command = command;
622: command = forced_command;
623: debug("Forced command '%.900s'", command);
624: }
625:
626: if (s->ttyfd != -1)
627: do_exec_pty(s, command);
628: else
629: do_exec_no_pty(s, command);
630:
1.92 markus 631: original_command = NULL;
1.90 markus 632: }
633:
634:
1.24 markus 635: /* administrative, login(1)-like work */
636: void
1.41 markus 637: do_login(Session *s, const char *command)
1.24 markus 638: {
639: char *time_string;
640: socklen_t fromlen;
641: struct sockaddr_storage from;
642: struct passwd * pw = s->pw;
643: pid_t pid = getpid();
644:
645: /*
646: * Get IP address of client. If the connection is not a socket, let
647: * the address be 0.0.0.0.
648: */
649: memset(&from, 0, sizeof(from));
1.148 stevesk 650: fromlen = sizeof(from);
1.24 markus 651: if (packet_connection_is_on_socket()) {
652: if (getpeername(packet_get_connection_in(),
1.112 deraadt 653: (struct sockaddr *) & from, &fromlen) < 0) {
1.24 markus 654: debug("getpeername: %.100s", strerror(errno));
655: fatal_cleanup();
656: }
657: }
1.25 markus 658:
1.24 markus 659: /* Record that there was a login on that tty from the remote host. */
1.133 markus 660: if (!use_privsep)
661: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
662: get_remote_name_or_ip(utmp_len,
663: options.verify_reverse_mapping),
1.148 stevesk 664: (struct sockaddr *)&from, fromlen);
1.24 markus 665:
1.73 djm 666: if (check_quietlogin(s, command))
1.24 markus 667: return;
1.73 djm 668:
1.134 markus 669: if (options.print_lastlog && s->last_login_time != 0) {
670: time_string = ctime(&s->last_login_time);
1.24 markus 671: if (strchr(time_string, '\n'))
672: *strchr(time_string, '\n') = 0;
1.134 markus 673: if (strcmp(s->hostname, "") == 0)
1.24 markus 674: printf("Last login: %s\r\n", time_string);
675: else
1.134 markus 676: printf("Last login: %s from %s\r\n", time_string,
677: s->hostname);
1.24 markus 678: }
1.73 djm 679:
680: do_motd();
681: }
682:
683: /*
684: * Display the message of the day.
685: */
686: void
687: do_motd(void)
688: {
689: FILE *f;
690: char buf[256];
691:
1.24 markus 692: if (options.print_motd) {
1.28 millert 693: #ifdef HAVE_LOGIN_CAP
694: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
695: "/etc/motd"), "r");
696: #else
1.24 markus 697: f = fopen("/etc/motd", "r");
1.28 millert 698: #endif
1.24 markus 699: if (f) {
700: while (fgets(buf, sizeof(buf), f))
701: fputs(buf, stdout);
702: fclose(f);
703: }
1.2 markus 704: }
1.73 djm 705: }
706:
707:
708: /*
709: * Check for quiet login, either .hushlogin or command given.
710: */
711: int
712: check_quietlogin(Session *s, const char *command)
713: {
714: char buf[256];
1.96 dugsong 715: struct passwd *pw = s->pw;
1.73 djm 716: struct stat st;
717:
718: /* Return 1 if .hushlogin exists or a command given. */
719: if (command != NULL)
720: return 1;
721: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
722: #ifdef HAVE_LOGIN_CAP
723: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
724: return 1;
725: #else
726: if (stat(buf, &st) >= 0)
727: return 1;
728: #endif
729: return 0;
1.1 markus 730: }
731:
732: /*
733: * Sets the value of the given variable in the environment. If the variable
734: * already exists, its value is overriden.
735: */
1.94 itojun 736: static void
1.45 markus 737: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 738: const char *value)
1.1 markus 739: {
1.45 markus 740: u_int i, namelen;
1.1 markus 741: char **env;
742:
743: /*
744: * Find the slot where the value should be stored. If the variable
745: * already exists, we reuse the slot; otherwise we append a new slot
746: * at the end of the array, expanding if necessary.
747: */
748: env = *envp;
749: namelen = strlen(name);
750: for (i = 0; env[i]; i++)
751: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
752: break;
753: if (env[i]) {
754: /* Reuse the slot. */
755: xfree(env[i]);
756: } else {
757: /* New variable. Expand if necessary. */
758: if (i >= (*envsizep) - 1) {
1.141 markus 759: if (*envsizep >= 1000)
760: fatal("child_set_env: too many env vars,"
761: " skipping: %.100s", name);
1.1 markus 762: (*envsizep) += 50;
763: env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
764: }
765: /* Need to set the NULL pointer at end of array beyond the new slot. */
766: env[i + 1] = NULL;
767: }
768:
769: /* Allocate space and format the variable in the appropriate slot. */
770: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
771: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
772: }
773:
774: /*
775: * Reads environment variables from the given file and adds/overrides them
776: * into the environment. If the file does not exist, this does nothing.
777: * Otherwise, it must consist of empty lines, comments (line starts with '#')
778: * and assignments of the form name=value. No other forms are allowed.
779: */
1.94 itojun 780: static void
1.45 markus 781: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 782: const char *filename)
1.1 markus 783: {
784: FILE *f;
785: char buf[4096];
786: char *cp, *value;
1.142 deraadt 787: u_int lineno = 0;
1.1 markus 788:
789: f = fopen(filename, "r");
790: if (!f)
791: return;
792:
793: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 794: if (++lineno > 1000)
795: fatal("Too many lines in environment file %s", filename);
1.1 markus 796: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
797: ;
798: if (!*cp || *cp == '#' || *cp == '\n')
799: continue;
800: if (strchr(cp, '\n'))
801: *strchr(cp, '\n') = '\0';
802: value = strchr(cp, '=');
803: if (value == NULL) {
1.142 deraadt 804: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
805: filename);
1.1 markus 806: continue;
807: }
1.14 deraadt 808: /*
809: * Replace the equals sign by nul, and advance value to
810: * the value string.
811: */
1.1 markus 812: *value = '\0';
813: value++;
814: child_set_env(env, envsize, cp, value);
815: }
816: fclose(f);
817: }
818:
1.127 markus 819: static char **
820: do_setup_env(Session *s, const char *shell)
1.1 markus 821: {
822: char buf[256];
1.127 markus 823: u_int i, envsize;
1.1 markus 824: char **env;
1.127 markus 825: struct passwd *pw = s->pw;
1.1 markus 826:
827: /* Initialize the environment. */
828: envsize = 100;
829: env = xmalloc(envsize * sizeof(char *));
830: env[0] = NULL;
831:
832: if (!options.use_login) {
833: /* Set basic environment. */
834: child_set_env(&env, &envsize, "USER", pw->pw_name);
835: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
836: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.28 millert 837: #ifdef HAVE_LOGIN_CAP
1.145 markus 838: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
839: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
840: else
841: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.28 millert 842: #else
1.29 millert 843: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1.28 millert 844: #endif
1.1 markus 845:
846: snprintf(buf, sizeof buf, "%.200s/%.50s",
847: _PATH_MAILDIR, pw->pw_name);
848: child_set_env(&env, &envsize, "MAIL", buf);
849:
850: /* Normal systems set SHELL by default. */
851: child_set_env(&env, &envsize, "SHELL", shell);
852: }
853: if (getenv("TZ"))
854: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
855:
856: /* Set custom environment options from RSA authentication. */
1.110 markus 857: if (!options.use_login) {
858: while (custom_environment) {
859: struct envstring *ce = custom_environment;
1.143 deraadt 860: char *str = ce->s;
1.127 markus 861:
1.143 deraadt 862: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 863: ;
1.143 deraadt 864: if (str[i] == '=') {
865: str[i] = 0;
866: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 867: }
868: custom_environment = ce->next;
869: xfree(ce->s);
870: xfree(ce);
1.1 markus 871: }
872: }
873:
1.149 stevesk 874: /* SSH_CLIENT deprecated */
1.1 markus 875: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 876: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 877: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 878:
879: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
880: get_remote_ipaddr(), get_remote_port(),
881: get_local_ipaddr(packet_get_connection_in()), get_local_port());
882: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 883:
1.60 markus 884: if (s->ttyfd != -1)
885: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
886: if (s->term)
887: child_set_env(&env, &envsize, "TERM", s->term);
888: if (s->display)
889: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 890: if (original_command)
891: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
892: original_command);
1.1 markus 893: #ifdef KRB4
1.96 dugsong 894: if (s->authctxt->krb4_ticket_file)
895: child_set_env(&env, &envsize, "KRBTKFILE",
1.112 deraadt 896: s->authctxt->krb4_ticket_file);
1.96 dugsong 897: #endif
898: #ifdef KRB5
899: if (s->authctxt->krb5_ticket_file)
900: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 901: s->authctxt->krb5_ticket_file);
1.96 dugsong 902: #endif
1.136 markus 903: if (auth_sock_name != NULL)
1.1 markus 904: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 905: auth_sock_name);
1.1 markus 906:
907: /* read $HOME/.ssh/environment. */
1.146 markus 908: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 909: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
910: pw->pw_dir);
1.1 markus 911: read_environment_file(&env, &envsize, buf);
912: }
913: if (debug_flag) {
914: /* dump the environment */
915: fprintf(stderr, "Environment:\n");
916: for (i = 0; env[i]; i++)
917: fprintf(stderr, " %.200s\n", env[i]);
918: }
1.127 markus 919: return env;
920: }
921:
922: /*
923: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
924: * first in this order).
925: */
926: static void
927: do_rc_files(Session *s, const char *shell)
928: {
929: FILE *f = NULL;
930: char cmd[1024];
931: int do_xauth;
932: struct stat st;
933:
934: do_xauth =
935: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
936:
937: /* ignore _PATH_SSH_USER_RC for subsystems */
938: if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
939: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
940: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
941: if (debug_flag)
942: fprintf(stderr, "Running %s\n", cmd);
943: f = popen(cmd, "w");
944: if (f) {
945: if (do_xauth)
946: fprintf(f, "%s %s\n", s->auth_proto,
947: s->auth_data);
948: pclose(f);
949: } else
950: fprintf(stderr, "Could not run %s\n",
951: _PATH_SSH_USER_RC);
952: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
953: if (debug_flag)
954: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
955: _PATH_SSH_SYSTEM_RC);
956: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
957: if (f) {
958: if (do_xauth)
959: fprintf(f, "%s %s\n", s->auth_proto,
960: s->auth_data);
961: pclose(f);
962: } else
963: fprintf(stderr, "Could not run %s\n",
964: _PATH_SSH_SYSTEM_RC);
965: } else if (do_xauth && options.xauth_location != NULL) {
966: /* Add authority data to .Xauthority if appropriate. */
967: if (debug_flag) {
968: fprintf(stderr,
1.151 stevesk 969: "Running %.500s remove %.100s\n",
970: options.xauth_location, s->auth_display);
971: fprintf(stderr,
972: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 973: options.xauth_location, s->auth_display,
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) {
1.151 stevesk 980: fprintf(f, "remove %s\n",
981: s->auth_display);
1.127 markus 982: fprintf(f, "add %s %s %s\n",
983: s->auth_display, s->auth_proto,
984: s->auth_data);
985: pclose(f);
986: } else {
987: fprintf(stderr, "Could not run %s\n",
988: cmd);
989: }
990: }
991: }
992:
993: static void
994: do_nologin(struct passwd *pw)
995: {
996: FILE *f = NULL;
997: char buf[1024];
998:
999: #ifdef HAVE_LOGIN_CAP
1000: if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1001: f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1002: _PATH_NOLOGIN), "r");
1003: #else
1004: if (pw->pw_uid)
1005: f = fopen(_PATH_NOLOGIN, "r");
1006: #endif
1007: if (f) {
1008: /* /etc/nologin exists. Print its contents and exit. */
1.150 stevesk 1009: log("User %.100s not allowed because %s exists",
1010: pw->pw_name, _PATH_NOLOGIN);
1.127 markus 1011: while (fgets(buf, sizeof(buf), f))
1012: fputs(buf, stderr);
1013: fclose(f);
1014: exit(254);
1015: }
1016: }
1017:
1018: /* Set login name, uid, gid, and groups. */
1.130 provos 1019: void
1.127 markus 1020: do_setusercontext(struct passwd *pw)
1021: {
1022: if (getuid() == 0 || geteuid() == 0) {
1023: #ifdef HAVE_LOGIN_CAP
1024: if (setusercontext(lc, pw, pw->pw_uid,
1025: (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1026: perror("unable to set user context");
1027: exit(1);
1028: }
1029: #else
1030: if (setlogin(pw->pw_name) < 0)
1031: error("setlogin failed: %s", strerror(errno));
1032: if (setgid(pw->pw_gid) < 0) {
1033: perror("setgid");
1034: exit(1);
1035: }
1036: /* Initialize the group list. */
1037: if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1038: perror("initgroups");
1039: exit(1);
1040: }
1041: endgrent();
1042:
1043: /* Permanently switch to the desired uid. */
1044: permanently_set_uid(pw);
1045: #endif
1046: }
1047: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1048: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1049: }
1050:
1.131 markus 1051: static void
1.130 provos 1052: launch_login(struct passwd *pw, const char *hostname)
1053: {
1054: /* Launch login(1). */
1055:
1056: execl("/usr/bin/login", "login", "-h", hostname,
1057: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1058:
1059: /* Login couldn't be executed, die. */
1060:
1061: perror("login");
1062: exit(1);
1063: }
1064:
1.127 markus 1065: /*
1066: * Performs common processing for the child, such as setting up the
1067: * environment, closing extra file descriptors, setting the user and group
1068: * ids, and executing the command or shell.
1069: */
1070: void
1071: do_child(Session *s, const char *command)
1072: {
1073: extern char **environ;
1074: char **env;
1075: char *argv[10];
1076: const char *shell, *shell0, *hostname = NULL;
1077: struct passwd *pw = s->pw;
1078: u_int i;
1079:
1080: /* remove hostkey from the child's memory */
1081: destroy_sensitive_data();
1082:
1083: /* login(1) is only called if we execute the login shell */
1084: if (options.use_login && command != NULL)
1085: options.use_login = 0;
1086:
1087: /*
1088: * Login(1) does this as well, and it needs uid 0 for the "-h"
1089: * switch, so we let login(1) to this for us.
1090: */
1091: if (!options.use_login) {
1092: do_nologin(pw);
1093: do_setusercontext(pw);
1094: }
1095:
1096: /*
1097: * Get the shell from the password data. An empty shell field is
1098: * legal, and means /bin/sh.
1099: */
1100: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 ! markus 1101:
! 1102: /*
! 1103: * Make sure $SHELL points to the shell from the password file,
! 1104: * even if shell is overridden from login.conf
! 1105: */
! 1106: env = do_setup_env(s, shell);
! 1107:
1.127 markus 1108: #ifdef HAVE_LOGIN_CAP
1109: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1110: #endif
1111:
1.26 millert 1112: /* we have to stash the hostname before we close our socket. */
1113: if (options.use_login)
1.70 stevesk 1114: hostname = get_remote_name_or_ip(utmp_len,
1.120 markus 1115: options.verify_reverse_mapping);
1.1 markus 1116: /*
1117: * Close the connection descriptors; note that this is the child, and
1118: * the server will still have the socket open, and it is important
1119: * that we do not shutdown it. Note that the descriptors cannot be
1120: * closed before building the environment, as we call
1121: * get_remote_ipaddr there.
1122: */
1123: if (packet_get_connection_in() == packet_get_connection_out())
1124: close(packet_get_connection_in());
1125: else {
1126: close(packet_get_connection_in());
1127: close(packet_get_connection_out());
1128: }
1129: /*
1130: * Close all descriptors related to channels. They will still remain
1131: * open in the parent.
1132: */
1133: /* XXX better use close-on-exec? -markus */
1134: channel_close_all();
1135:
1136: /*
1137: * Close any extra file descriptors. Note that there may still be
1138: * descriptors left by system functions. They will be closed later.
1139: */
1140: endpwent();
1141:
1142: /*
1143: * Close any extra open file descriptors so that we don\'t have them
1144: * hanging around in clients. Note that we want to do this after
1145: * initgroups, because at least on Solaris 2.3 it leaves file
1146: * descriptors open.
1147: */
1148: for (i = 3; i < 64; i++)
1149: close(i);
1150:
1151: /*
1.125 deraadt 1152: * Must take new environment into use so that .ssh/rc,
1153: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1154: */
1155: environ = env;
1.102 markus 1156:
1157: #ifdef AFS
1158: /* Try to get AFS tokens for the local cell. */
1159: if (k_hasafs()) {
1160: char cell[64];
1.112 deraadt 1161:
1.102 markus 1162: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1163: krb_afslog(cell, 0);
1.112 deraadt 1164:
1.102 markus 1165: krb_afslog(0, 0);
1166: }
1167: #endif /* AFS */
1.104 markus 1168:
1169: /* Change current directory to the user\'s home directory. */
1170: if (chdir(pw->pw_dir) < 0) {
1171: fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1172: pw->pw_dir, strerror(errno));
1173: #ifdef HAVE_LOGIN_CAP
1174: if (login_getcapbool(lc, "requirehome", 0))
1175: exit(1);
1176: #endif
1177: }
1.1 markus 1178:
1.127 markus 1179: if (!options.use_login)
1180: do_rc_files(s, shell);
1.67 markus 1181:
1182: /* restore SIGPIPE for child */
1183: signal(SIGPIPE, SIG_DFL);
1184:
1.127 markus 1185: if (options.use_login) {
1.130 provos 1186: launch_login(pw, hostname);
1187: /* NEVERREACHED */
1.127 markus 1188: }
1189:
1190: /* Get the last component of the shell name. */
1191: if ((shell0 = strrchr(shell, '/')) != NULL)
1192: shell0++;
1193: else
1194: shell0 = shell;
1195:
1.1 markus 1196: /*
1197: * If we have no command, execute the shell. In this case, the shell
1198: * name to be passed in argv[0] is preceded by '-' to indicate that
1199: * this is a login shell.
1200: */
1201: if (!command) {
1.127 markus 1202: char argv0[256];
1.1 markus 1203:
1.127 markus 1204: /* Start the shell. Set initial character to '-'. */
1205: argv0[0] = '-';
1.1 markus 1206:
1.127 markus 1207: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1208: >= sizeof(argv0) - 1) {
1.127 markus 1209: errno = EINVAL;
1.1 markus 1210: perror(shell);
1211: exit(1);
1.127 markus 1212: }
1.1 markus 1213:
1.127 markus 1214: /* Execute the shell. */
1215: argv[0] = argv0;
1216: argv[1] = NULL;
1217: execve(shell, argv, env);
1218:
1219: /* Executing the shell failed. */
1220: perror(shell);
1221: exit(1);
1.1 markus 1222: }
1223: /*
1224: * Execute the command using the user's shell. This uses the -c
1225: * option to execute the command.
1226: */
1.127 markus 1227: argv[0] = (char *) shell0;
1.1 markus 1228: argv[1] = "-c";
1229: argv[2] = (char *) command;
1230: argv[3] = NULL;
1231: execve(shell, argv, env);
1232: perror(shell);
1233: exit(1);
1234: }
1235:
1236: Session *
1237: session_new(void)
1238: {
1239: int i;
1240: static int did_init = 0;
1241: if (!did_init) {
1242: debug("session_new: init");
1.112 deraadt 1243: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1244: sessions[i].used = 0;
1245: }
1246: did_init = 1;
1247: }
1.112 deraadt 1248: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1249: Session *s = &sessions[i];
1250: if (! s->used) {
1.68 djm 1251: memset(s, 0, sizeof(*s));
1.1 markus 1252: s->chanid = -1;
1253: s->ptyfd = -1;
1254: s->ttyfd = -1;
1255: s->used = 1;
1.85 markus 1256: s->self = i;
1.1 markus 1257: debug("session_new: session %d", i);
1258: return s;
1259: }
1260: }
1261: return NULL;
1262: }
1263:
1.94 itojun 1264: static void
1.1 markus 1265: session_dump(void)
1266: {
1267: int i;
1.112 deraadt 1268: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1269: Session *s = &sessions[i];
1.137 mpech 1270: debug("dump: used %d session %d %p channel %d pid %ld",
1.1 markus 1271: s->used,
1272: s->self,
1273: s,
1274: s->chanid,
1.137 mpech 1275: (long)s->pid);
1.1 markus 1276: }
1277: }
1278:
1.2 markus 1279: int
1.97 markus 1280: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1281: {
1282: Session *s = session_new();
1283: debug("session_open: channel %d", chanid);
1284: if (s == NULL) {
1285: error("no more sessions");
1286: return 0;
1287: }
1.97 markus 1288: s->authctxt = authctxt;
1289: s->pw = authctxt->pw;
1.7 markus 1290: if (s->pw == NULL)
1.54 stevesk 1291: fatal("no user for session %d", s->self);
1.2 markus 1292: debug("session_open: session %d: link with channel %d", s->self, chanid);
1293: s->chanid = chanid;
1294: return 1;
1295: }
1296:
1.130 provos 1297: Session *
1298: session_by_tty(char *tty)
1299: {
1300: int i;
1301: for (i = 0; i < MAX_SESSIONS; i++) {
1302: Session *s = &sessions[i];
1303: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1304: debug("session_by_tty: session %d tty %s", i, tty);
1305: return s;
1306: }
1307: }
1308: debug("session_by_tty: unknown tty %.100s", tty);
1309: session_dump();
1310: return NULL;
1311: }
1312:
1.94 itojun 1313: static Session *
1.2 markus 1314: session_by_channel(int id)
1315: {
1316: int i;
1.112 deraadt 1317: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1318: Session *s = &sessions[i];
1319: if (s->used && s->chanid == id) {
1320: debug("session_by_channel: session %d channel %d", i, id);
1321: return s;
1322: }
1323: }
1324: debug("session_by_channel: unknown channel %d", id);
1325: session_dump();
1326: return NULL;
1327: }
1328:
1.94 itojun 1329: static Session *
1.2 markus 1330: session_by_pid(pid_t pid)
1331: {
1332: int i;
1.137 mpech 1333: debug("session_by_pid: pid %ld", (long)pid);
1.112 deraadt 1334: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1335: Session *s = &sessions[i];
1336: if (s->used && s->pid == pid)
1337: return s;
1338: }
1.137 mpech 1339: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1340: session_dump();
1341: return NULL;
1342: }
1343:
1.94 itojun 1344: static int
1.2 markus 1345: session_window_change_req(Session *s)
1346: {
1347: s->col = packet_get_int();
1348: s->row = packet_get_int();
1349: s->xpixel = packet_get_int();
1350: s->ypixel = packet_get_int();
1.116 markus 1351: packet_check_eom();
1.2 markus 1352: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1353: return 1;
1354: }
1355:
1.94 itojun 1356: static int
1.2 markus 1357: session_pty_req(Session *s)
1358: {
1.45 markus 1359: u_int len;
1.72 stevesk 1360: int n_bytes;
1.132 markus 1361:
1.86 markus 1362: if (no_pty_flag) {
1363: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1364: return 0;
1.86 markus 1365: }
1366: if (s->ttyfd != -1) {
1367: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1368: return 0;
1.134 markus 1369: }
1370: /* Get the time and hostname when the user last logged in. */
1371: if (options.print_lastlog) {
1372: s->hostname[0] = '\0';
1373: s->last_login_time = get_last_login_time(s->pw->pw_uid,
1374: s->pw->pw_name, s->hostname, sizeof(s->hostname));
1.86 markus 1375: }
1376:
1.2 markus 1377: s->term = packet_get_string(&len);
1.86 markus 1378:
1379: if (compat20) {
1380: s->col = packet_get_int();
1381: s->row = packet_get_int();
1382: } else {
1383: s->row = packet_get_int();
1384: s->col = packet_get_int();
1385: }
1.2 markus 1386: s->xpixel = packet_get_int();
1387: s->ypixel = packet_get_int();
1388:
1389: if (strcmp(s->term, "") == 0) {
1390: xfree(s->term);
1391: s->term = NULL;
1392: }
1.86 markus 1393:
1.2 markus 1394: /* Allocate a pty and open it. */
1.86 markus 1395: debug("Allocating pty.");
1.130 provos 1396: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1.86 markus 1397: if (s->term)
1398: xfree(s->term);
1.2 markus 1399: s->term = NULL;
1400: s->ptyfd = -1;
1401: s->ttyfd = -1;
1402: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1403: return 0;
1.2 markus 1404: }
1405: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1406:
1407: /* for SSH1 the tty modes length is not given */
1408: if (!compat20)
1409: n_bytes = packet_remaining();
1410: tty_parse_modes(s->ttyfd, &n_bytes);
1411:
1.2 markus 1412: /*
1413: * Add a cleanup function to clear the utmp entry and record logout
1414: * time in case we call fatal() (e.g., the connection gets closed).
1415: */
1.85 markus 1416: fatal_add_cleanup(session_pty_cleanup, (void *)s);
1.130 provos 1417: if (!use_privsep)
1418: pty_setowner(s->pw, s->tty);
1.86 markus 1419:
1420: /* Set window size from the packet. */
1.2 markus 1421: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1422:
1.116 markus 1423: packet_check_eom();
1.9 markus 1424: session_proctitle(s);
1.2 markus 1425: return 1;
1426: }
1427:
1.94 itojun 1428: static int
1.7 markus 1429: session_subsystem_req(Session *s)
1430: {
1.105 markus 1431: struct stat st;
1.45 markus 1432: u_int len;
1.7 markus 1433: int success = 0;
1.105 markus 1434: char *cmd, *subsys = packet_get_string(&len);
1.18 jakob 1435: int i;
1.7 markus 1436:
1.116 markus 1437: packet_check_eom();
1.121 stevesk 1438: log("subsystem request for %.100s", subsys);
1.18 jakob 1439:
1440: for (i = 0; i < options.num_subsystems; i++) {
1.105 markus 1441: if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1442: cmd = options.subsystem_command[i];
1443: if (stat(cmd, &st) < 0) {
1444: error("subsystem: cannot stat %s: %s", cmd,
1445: strerror(errno));
1446: break;
1447: }
1448: debug("subsystem: exec() %s", cmd);
1.64 markus 1449: s->is_subsystem = 1;
1.105 markus 1450: do_exec(s, cmd);
1.18 jakob 1451: success = 1;
1.122 markus 1452: break;
1.18 jakob 1453: }
1454: }
1455:
1456: if (!success)
1.121 stevesk 1457: log("subsystem request for %.100s failed, subsystem not found",
1.105 markus 1458: subsys);
1.7 markus 1459:
1460: xfree(subsys);
1461: return success;
1462: }
1463:
1.94 itojun 1464: static int
1.7 markus 1465: session_x11_req(Session *s)
1466: {
1.81 markus 1467: int success;
1.7 markus 1468:
1469: s->single_connection = packet_get_char();
1470: s->auth_proto = packet_get_string(NULL);
1471: s->auth_data = packet_get_string(NULL);
1472: s->screen = packet_get_int();
1.116 markus 1473: packet_check_eom();
1.7 markus 1474:
1.81 markus 1475: success = session_setup_x11fwd(s);
1476: if (!success) {
1.7 markus 1477: xfree(s->auth_proto);
1478: xfree(s->auth_data);
1.84 markus 1479: s->auth_proto = NULL;
1480: s->auth_data = NULL;
1.7 markus 1481: }
1.81 markus 1482: return success;
1.7 markus 1483: }
1484:
1.94 itojun 1485: static int
1.19 markus 1486: session_shell_req(Session *s)
1487: {
1.116 markus 1488: packet_check_eom();
1.90 markus 1489: do_exec(s, NULL);
1.19 markus 1490: return 1;
1491: }
1492:
1.94 itojun 1493: static int
1.19 markus 1494: session_exec_req(Session *s)
1495: {
1.45 markus 1496: u_int len;
1.19 markus 1497: char *command = packet_get_string(&len);
1.116 markus 1498: packet_check_eom();
1.90 markus 1499: do_exec(s, command);
1.92 markus 1500: xfree(command);
1.19 markus 1501: return 1;
1502: }
1503:
1.94 itojun 1504: static int
1.43 markus 1505: session_auth_agent_req(Session *s)
1506: {
1507: static int called = 0;
1.116 markus 1508: packet_check_eom();
1.44 markus 1509: if (no_agent_forwarding_flag) {
1510: debug("session_auth_agent_req: no_agent_forwarding_flag");
1511: return 0;
1512: }
1.43 markus 1513: if (called) {
1514: return 0;
1515: } else {
1516: called = 1;
1517: return auth_input_request_forwarding(s->pw);
1518: }
1519: }
1520:
1.123 markus 1521: int
1522: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1523: {
1524: int success = 0;
1525: Session *s;
1526:
1.123 markus 1527: if ((s = session_by_channel(c->self)) == NULL) {
1528: log("session_input_channel_req: no session %d req %.100s",
1529: c->self, rtype);
1530: return 0;
1531: }
1532: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1533:
1534: /*
1.64 markus 1535: * a session is in LARVAL state until a shell, a command
1536: * or a subsystem is executed
1.2 markus 1537: */
1538: if (c->type == SSH_CHANNEL_LARVAL) {
1539: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1540: success = session_shell_req(s);
1.2 markus 1541: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1542: success = session_exec_req(s);
1.2 markus 1543: } else if (strcmp(rtype, "pty-req") == 0) {
1.3 markus 1544: success = session_pty_req(s);
1.7 markus 1545: } else if (strcmp(rtype, "x11-req") == 0) {
1546: success = session_x11_req(s);
1.43 markus 1547: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1548: success = session_auth_agent_req(s);
1.7 markus 1549: } else if (strcmp(rtype, "subsystem") == 0) {
1550: success = session_subsystem_req(s);
1.2 markus 1551: }
1552: }
1553: if (strcmp(rtype, "window-change") == 0) {
1554: success = session_window_change_req(s);
1555: }
1.123 markus 1556: return success;
1.2 markus 1557: }
1558:
1559: void
1560: session_set_fds(Session *s, int fdin, int fdout, int fderr)
1561: {
1562: if (!compat20)
1563: fatal("session_set_fds: called for proto != 2.0");
1564: /*
1565: * now that have a child and a pipe to the child,
1566: * we can activate our channel and register the fd's
1567: */
1568: if (s->chanid == -1)
1569: fatal("no channel for session %d", s->self);
1570: channel_set_fds(s->chanid,
1571: fdout, fdin, fderr,
1.42 markus 1572: fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.126 markus 1573: 1,
1574: CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1575: }
1576:
1.85 markus 1577: /*
1578: * Function to perform pty cleanup. Also called if we get aborted abnormally
1579: * (e.g., due to a dropped connection).
1580: */
1.130 provos 1581: void
1582: session_pty_cleanup2(void *session)
1.1 markus 1583: {
1.85 markus 1584: Session *s = session;
1585:
1586: if (s == NULL) {
1587: error("session_pty_cleanup: no session");
1588: return;
1589: }
1590: if (s->ttyfd == -1)
1.1 markus 1591: return;
1592:
1.54 stevesk 1593: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1594:
1595: /* Record that the user has logged out. */
1.85 markus 1596: if (s->pid != 0)
1597: record_logout(s->pid, s->tty);
1.1 markus 1598:
1599: /* Release the pseudo-tty. */
1.130 provos 1600: if (getuid() == 0)
1601: pty_release(s->tty);
1.1 markus 1602:
1603: /*
1604: * Close the server side of the socket pairs. We must do this after
1605: * the pty cleanup, so that another process doesn't get this pty
1606: * while we're still cleaning up.
1607: */
1608: if (close(s->ptymaster) < 0)
1.130 provos 1609: error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1.108 markus 1610:
1611: /* unlink pty from session */
1612: s->ttyfd = -1;
1.2 markus 1613: }
1614:
1.130 provos 1615: void
1616: session_pty_cleanup(void *session)
1617: {
1618: PRIVSEP(session_pty_cleanup2(session));
1619: }
1620:
1.147 markus 1621: static char *
1622: sig2name(int sig)
1623: {
1624: #define SSH_SIG(x) if (sig == SIG ## x) return #x
1625: SSH_SIG(ABRT);
1626: SSH_SIG(ALRM);
1627: SSH_SIG(FPE);
1628: SSH_SIG(HUP);
1629: SSH_SIG(ILL);
1630: SSH_SIG(INT);
1631: SSH_SIG(KILL);
1632: SSH_SIG(PIPE);
1633: SSH_SIG(QUIT);
1634: SSH_SIG(SEGV);
1635: SSH_SIG(TERM);
1636: SSH_SIG(USR1);
1637: SSH_SIG(USR2);
1638: #undef SSH_SIG
1639: return "SIG@openssh.com";
1640: }
1641:
1.94 itojun 1642: static void
1.2 markus 1643: session_exit_message(Session *s, int status)
1644: {
1645: Channel *c;
1.124 markus 1646:
1647: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 1648: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 1649: s->self, s->chanid);
1.137 mpech 1650: debug("session_exit_message: session %d channel %d pid %ld",
1651: s->self, s->chanid, (long)s->pid);
1.2 markus 1652:
1653: if (WIFEXITED(status)) {
1.124 markus 1654: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 1655: packet_put_int(WEXITSTATUS(status));
1656: packet_send();
1657: } else if (WIFSIGNALED(status)) {
1.124 markus 1658: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 1659: packet_put_cstring(sig2name(WTERMSIG(status)));
1.2 markus 1660: packet_put_char(WCOREDUMP(status));
1661: packet_put_cstring("");
1662: packet_put_cstring("");
1663: packet_send();
1664: } else {
1665: /* Some weird exit cause. Just exit. */
1666: packet_disconnect("wait returned status %04x.", status);
1667: }
1668:
1669: /* disconnect channel */
1670: debug("session_exit_message: release channel %d", s->chanid);
1671: channel_cancel_cleanup(s->chanid);
1.5 markus 1672: /*
1673: * emulate a write failure with 'chan_write_failed', nobody will be
1674: * interested in data we write.
1675: * Note that we must not call 'chan_read_failed', since there could
1676: * be some more data waiting in the pipe.
1677: */
1.8 markus 1678: if (c->ostate != CHAN_OUTPUT_CLOSED)
1679: chan_write_failed(c);
1.2 markus 1680: s->chanid = -1;
1681: }
1682:
1.130 provos 1683: void
1.85 markus 1684: session_close(Session *s)
1.2 markus 1685: {
1.137 mpech 1686: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.85 markus 1687: if (s->ttyfd != -1) {
1688: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1689: session_pty_cleanup(s);
1690: }
1.2 markus 1691: if (s->term)
1692: xfree(s->term);
1693: if (s->display)
1694: xfree(s->display);
1.118 stevesk 1695: if (s->auth_display)
1696: xfree(s->auth_display);
1.2 markus 1697: if (s->auth_data)
1698: xfree(s->auth_data);
1699: if (s->auth_proto)
1700: xfree(s->auth_proto);
1701: s->used = 0;
1.9 markus 1702: session_proctitle(s);
1.2 markus 1703: }
1704:
1705: void
1706: session_close_by_pid(pid_t pid, int status)
1707: {
1708: Session *s = session_by_pid(pid);
1709: if (s == NULL) {
1.137 mpech 1710: debug("session_close_by_pid: no session for pid %ld",
1711: (long)pid);
1.2 markus 1712: return;
1713: }
1714: if (s->chanid != -1)
1715: session_exit_message(s, status);
1716: session_close(s);
1.98 markus 1717: }
1718:
1.2 markus 1719: /*
1720: * this is called when a channel dies before
1721: * the session 'child' itself dies
1722: */
1723: void
1724: session_close_by_channel(int id, void *arg)
1725: {
1726: Session *s = session_by_channel(id);
1727: if (s == NULL) {
1.107 markus 1728: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 1729: return;
1730: }
1.137 mpech 1731: debug("session_close_by_channel: channel %d child %ld",
1732: id, (long)s->pid);
1.107 markus 1733: if (s->pid != 0) {
1734: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 1735: /*
1736: * delay detach of session, but release pty, since
1737: * the fd's to the child are already closed
1738: */
1739: if (s->ttyfd != -1) {
1740: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1741: session_pty_cleanup(s);
1742: }
1.107 markus 1743: return;
1744: }
1745: /* detach by removing callback */
1.2 markus 1746: channel_cancel_cleanup(s->chanid);
1747: s->chanid = -1;
1.106 markus 1748: session_close(s);
1749: }
1750:
1751: void
1.130 provos 1752: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 1753: {
1754: int i;
1.112 deraadt 1755: for (i = 0; i < MAX_SESSIONS; i++) {
1.106 markus 1756: Session *s = &sessions[i];
1.130 provos 1757: if (s->used) {
1758: if (closefunc != NULL)
1759: closefunc(s);
1760: else
1761: session_close(s);
1762: }
1.2 markus 1763: }
1.9 markus 1764: }
1765:
1.94 itojun 1766: static char *
1.9 markus 1767: session_tty_list(void)
1768: {
1769: static char buf[1024];
1770: int i;
1771: buf[0] = '\0';
1.112 deraadt 1772: for (i = 0; i < MAX_SESSIONS; i++) {
1.9 markus 1773: Session *s = &sessions[i];
1774: if (s->used && s->ttyfd != -1) {
1775: if (buf[0] != '\0')
1776: strlcat(buf, ",", sizeof buf);
1777: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1778: }
1779: }
1780: if (buf[0] == '\0')
1781: strlcpy(buf, "notty", sizeof buf);
1782: return buf;
1783: }
1784:
1785: void
1786: session_proctitle(Session *s)
1787: {
1788: if (s->pw == NULL)
1789: error("no user for session %d", s->self);
1790: else
1791: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 1792: }
1793:
1794: int
1795: session_setup_x11fwd(Session *s)
1796: {
1797: struct stat st;
1.109 stevesk 1798: char display[512], auth_display[512];
1799: char hostname[MAXHOSTNAMELEN];
1.81 markus 1800:
1801: if (no_x11_forwarding_flag) {
1802: packet_send_debug("X11 forwarding disabled in user configuration file.");
1803: return 0;
1804: }
1805: if (!options.x11_forwarding) {
1806: debug("X11 forwarding disabled in server configuration file.");
1807: return 0;
1808: }
1809: if (!options.xauth_location ||
1810: (stat(options.xauth_location, &st) == -1)) {
1811: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 1812: return 0;
1813: }
1814: if (options.use_login) {
1815: packet_send_debug("X11 forwarding disabled; "
1816: "not compatible with UseLogin=yes.");
1.81 markus 1817: return 0;
1818: }
1.87 markus 1819: if (s->display != NULL) {
1.81 markus 1820: debug("X11 display already set.");
1821: return 0;
1822: }
1.140 deraadt 1823: if (x11_create_display_inet(options.x11_display_offset,
1824: options.x11_use_localhost, s->single_connection,
1825: &s->display_number) == -1) {
1.87 markus 1826: debug("x11_create_display_inet failed.");
1.81 markus 1827: return 0;
1828: }
1.109 stevesk 1829:
1830: /* Set up a suitable value for the DISPLAY variable. */
1831: if (gethostname(hostname, sizeof(hostname)) < 0)
1832: fatal("gethostname: %.100s", strerror(errno));
1833: /*
1834: * auth_display must be used as the displayname when the
1835: * authorization entry is added with xauth(1). This will be
1836: * different than the DISPLAY string for localhost displays.
1837: */
1.119 stevesk 1838: if (options.x11_use_localhost) {
1.140 deraadt 1839: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 1840: s->display_number, s->screen);
1.140 deraadt 1841: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 1842: s->display_number, s->screen);
1.109 stevesk 1843: s->display = xstrdup(display);
1.118 stevesk 1844: s->auth_display = xstrdup(auth_display);
1.109 stevesk 1845: } else {
1.140 deraadt 1846: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 1847: s->display_number, s->screen);
1848: s->display = xstrdup(display);
1.118 stevesk 1849: s->auth_display = xstrdup(display);
1.109 stevesk 1850: }
1851:
1.81 markus 1852: return 1;
1.2 markus 1853: }
1854:
1.94 itojun 1855: static void
1.49 markus 1856: do_authenticated2(Authctxt *authctxt)
1.2 markus 1857: {
1.97 markus 1858: server_loop2(authctxt);
1.1 markus 1859: }
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