Annotation of src/usr.bin/ssh/session.c, Revision 1.153
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"
1.153 ! markus 36: RCSID("$OpenBSD: session.c,v 1.152 2002/12/10 08:56:00 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: {
1.153 ! markus 191: setproctitle("%s", authctxt->pw->pw_name);
! 192:
1.65 markus 193: /*
194: * Cancel the alarm we set to limit the time taken for
195: * authentication.
196: */
197: alarm(0);
198: if (startup_pipe != -1) {
199: close(startup_pipe);
200: startup_pipe = -1;
201: }
202: /* setup the channel layer */
203: if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
204: channel_permit_all_opens();
205:
206: if (compat20)
207: do_authenticated2(authctxt);
208: else
209: do_authenticated1(authctxt);
1.79 markus 210:
1.87 markus 211: /* remove agent socket */
1.136 markus 212: if (auth_sock_name != NULL)
1.80 markus 213: auth_sock_cleanup_proc(authctxt->pw);
1.96 dugsong 214: #ifdef KRB4
215: if (options.kerberos_ticket_cleanup)
216: krb4_cleanup_proc(authctxt);
217: #endif
218: #ifdef KRB5
219: if (options.kerberos_ticket_cleanup)
220: krb5_cleanup_proc(authctxt);
221: #endif
1.65 markus 222: }
223:
1.1 markus 224: /*
225: * Prepares for an interactive session. This is called after the user has
226: * been successfully authenticated. During this message exchange, pseudo
227: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
228: * are requested, etc.
229: */
1.94 itojun 230: static void
1.65 markus 231: do_authenticated1(Authctxt *authctxt)
1.1 markus 232: {
233: Session *s;
1.65 markus 234: char *command;
1.117 markus 235: int success, type, screen_flag;
1.139 deraadt 236: int enable_compression_after_reply = 0;
237: u_int proto_len, data_len, dlen, compression_level = 0;
1.1 markus 238:
1.61 markus 239: s = session_new();
1.96 dugsong 240: s->authctxt = authctxt;
1.65 markus 241: s->pw = authctxt->pw;
1.28 millert 242:
1.1 markus 243: /*
244: * We stay in this loop until the client requests to execute a shell
245: * or a command.
246: */
247: for (;;) {
1.65 markus 248: success = 0;
1.1 markus 249:
250: /* Get a packet from the client. */
1.117 markus 251: type = packet_read();
1.1 markus 252:
253: /* Process the packet. */
254: switch (type) {
255: case SSH_CMSG_REQUEST_COMPRESSION:
256: compression_level = packet_get_int();
1.116 markus 257: packet_check_eom();
1.1 markus 258: if (compression_level < 1 || compression_level > 9) {
259: packet_send_debug("Received illegal compression level %d.",
1.112 deraadt 260: compression_level);
1.138 markus 261: break;
262: }
263: if (!options.compression) {
264: debug2("compression disabled");
1.1 markus 265: break;
266: }
267: /* Enable compression after we have responded with SUCCESS. */
268: enable_compression_after_reply = 1;
269: success = 1;
270: break;
271:
272: case SSH_CMSG_REQUEST_PTY:
1.86 markus 273: success = session_pty_req(s);
1.1 markus 274: break;
275:
276: case SSH_CMSG_X11_REQUEST_FORWARDING:
277: s->auth_proto = packet_get_string(&proto_len);
278: s->auth_data = packet_get_string(&data_len);
279:
1.57 markus 280: screen_flag = packet_get_protocol_flags() &
281: SSH_PROTOFLAG_SCREEN_NUMBER;
282: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
283:
284: if (packet_remaining() == 4) {
285: if (!screen_flag)
286: debug2("Buggy client: "
287: "X11 screen flag missing");
1.1 markus 288: s->screen = packet_get_int();
1.56 markus 289: } else {
1.1 markus 290: s->screen = 0;
1.56 markus 291: }
1.116 markus 292: packet_check_eom();
1.81 markus 293: success = session_setup_x11fwd(s);
294: if (!success) {
295: xfree(s->auth_proto);
296: xfree(s->auth_data);
1.84 markus 297: s->auth_proto = NULL;
298: s->auth_data = NULL;
1.1 markus 299: }
300: break;
301:
302: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
303: if (no_agent_forwarding_flag || compat13) {
304: debug("Authentication agent forwarding not permitted for this authentication.");
305: break;
306: }
307: debug("Received authentication agent forwarding request.");
1.65 markus 308: success = auth_input_request_forwarding(s->pw);
1.1 markus 309: break;
310:
311: case SSH_CMSG_PORT_FORWARD_REQUEST:
312: if (no_port_forwarding_flag) {
313: debug("Port forwarding not permitted for this authentication.");
1.39 markus 314: break;
315: }
316: if (!options.allow_tcp_forwarding) {
317: debug("Port forwarding not permitted.");
1.1 markus 318: break;
319: }
320: debug("Received TCP/IP port forwarding request.");
1.65 markus 321: channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
1.1 markus 322: success = 1;
323: break;
324:
325: case SSH_CMSG_MAX_PACKET_SIZE:
326: if (packet_set_maxsize(packet_get_int()) > 0)
327: success = 1;
328: break;
1.112 deraadt 329:
1.96 dugsong 330: #if defined(AFS) || defined(KRB5)
331: case SSH_CMSG_HAVE_KERBEROS_TGT:
332: if (!options.kerberos_tgt_passing) {
333: verbose("Kerberos TGT passing disabled.");
334: } else {
335: char *kdata = packet_get_string(&dlen);
1.116 markus 336: packet_check_eom();
1.112 deraadt 337:
1.96 dugsong 338: /* XXX - 0x41, see creds_to_radix version */
339: if (kdata[0] != 0x41) {
340: #ifdef KRB5
341: krb5_data tgt;
342: tgt.data = kdata;
343: tgt.length = dlen;
1.112 deraadt 344:
1.96 dugsong 345: if (auth_krb5_tgt(s->authctxt, &tgt))
346: success = 1;
347: else
348: verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
349: #endif /* KRB5 */
350: } else {
351: #ifdef AFS
352: if (auth_krb4_tgt(s->authctxt, kdata))
353: success = 1;
354: else
355: verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
356: #endif /* AFS */
357: }
358: xfree(kdata);
359: }
360: break;
361: #endif /* AFS || KRB5 */
1.112 deraadt 362:
1.96 dugsong 363: #ifdef AFS
364: case SSH_CMSG_HAVE_AFS_TOKEN:
365: if (!options.afs_token_passing || !k_hasafs()) {
366: verbose("AFS token passing disabled.");
367: } else {
368: /* Accept AFS token. */
369: char *token = packet_get_string(&dlen);
1.116 markus 370: packet_check_eom();
1.112 deraadt 371:
1.96 dugsong 372: if (auth_afs_token(s->authctxt, token))
373: success = 1;
374: else
375: verbose("AFS token refused for %.100s",
376: s->authctxt->user);
377: xfree(token);
378: }
379: break;
380: #endif /* AFS */
1.1 markus 381:
382: case SSH_CMSG_EXEC_SHELL:
383: case SSH_CMSG_EXEC_CMD:
384: if (type == SSH_CMSG_EXEC_CMD) {
385: command = packet_get_string(&dlen);
386: debug("Exec command '%.500s'", command);
1.92 markus 387: do_exec(s, command);
388: xfree(command);
1.1 markus 389: } else {
1.92 markus 390: do_exec(s, NULL);
1.1 markus 391: }
1.116 markus 392: packet_check_eom();
1.82 markus 393: session_close(s);
1.1 markus 394: return;
395:
396: default:
397: /*
398: * Any unknown messages in this phase are ignored,
399: * and a failure message is returned.
400: */
401: log("Unknown packet type received after authentication: %d", type);
402: }
403: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
404: packet_send();
405: packet_write_wait();
406:
407: /* Enable compression now that we have replied if appropriate. */
408: if (enable_compression_after_reply) {
409: enable_compression_after_reply = 0;
410: packet_start_compression(compression_level);
411: }
412: }
413: }
414:
415: /*
416: * This is called to fork and execute a command when we have no tty. This
417: * will call do_child from the child, and server_loop from the parent after
418: * setting up file descriptors and such.
419: */
1.4 markus 420: void
1.63 markus 421: do_exec_no_pty(Session *s, const char *command)
1.1 markus 422: {
1.137 mpech 423: pid_t pid;
1.1 markus 424:
425: #ifdef USE_PIPES
426: int pin[2], pout[2], perr[2];
427: /* Allocate pipes for communicating with the program. */
428: if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
429: packet_disconnect("Could not create pipes: %.100s",
430: strerror(errno));
431: #else /* USE_PIPES */
432: int inout[2], err[2];
433: /* Uses socket pairs to communicate with the program. */
434: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
435: socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
436: packet_disconnect("Could not create socket pairs: %.100s",
437: strerror(errno));
438: #endif /* USE_PIPES */
439: if (s == NULL)
440: fatal("do_exec_no_pty: no session");
441:
1.9 markus 442: session_proctitle(s);
1.1 markus 443:
444: /* Fork the child. */
445: if ((pid = fork()) == 0) {
1.144 markus 446: fatal_remove_all_cleanups();
447:
1.1 markus 448: /* Child. Reinitialize the log since the pid has changed. */
449: log_init(__progname, options.log_level, options.log_facility, log_stderr);
450:
451: /*
452: * Create a new session and process group since the 4.4BSD
453: * setlogin() affects the entire process group.
454: */
455: if (setsid() < 0)
456: error("setsid failed: %.100s", strerror(errno));
457:
458: #ifdef USE_PIPES
459: /*
460: * Redirect stdin. We close the parent side of the socket
461: * pair, and make the child side the standard input.
462: */
463: close(pin[1]);
464: if (dup2(pin[0], 0) < 0)
465: perror("dup2 stdin");
466: close(pin[0]);
467:
468: /* Redirect stdout. */
469: close(pout[0]);
470: if (dup2(pout[1], 1) < 0)
471: perror("dup2 stdout");
472: close(pout[1]);
473:
474: /* Redirect stderr. */
475: close(perr[0]);
476: if (dup2(perr[1], 2) < 0)
477: perror("dup2 stderr");
478: close(perr[1]);
479: #else /* USE_PIPES */
480: /*
481: * Redirect stdin, stdout, and stderr. Stdin and stdout will
482: * use the same socket, as some programs (particularly rdist)
483: * seem to depend on it.
484: */
485: close(inout[1]);
486: close(err[1]);
487: if (dup2(inout[0], 0) < 0) /* stdin */
488: perror("dup2 stdin");
489: if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
490: perror("dup2 stdout");
491: if (dup2(err[0], 2) < 0) /* stderr */
492: perror("dup2 stderr");
493: #endif /* USE_PIPES */
494:
495: /* Do processing for the child (exec command etc). */
1.60 markus 496: do_child(s, command);
1.1 markus 497: /* NOTREACHED */
498: }
499: if (pid < 0)
500: packet_disconnect("fork failed: %.100s", strerror(errno));
501: s->pid = pid;
1.47 markus 502: /* Set interactive/non-interactive mode. */
1.48 markus 503: packet_set_interactive(s->display != NULL);
1.1 markus 504: #ifdef USE_PIPES
505: /* We are the parent. Close the child sides of the pipes. */
506: close(pin[0]);
507: close(pout[1]);
508: close(perr[1]);
509:
1.2 markus 510: if (compat20) {
1.64 markus 511: session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
1.2 markus 512: } else {
513: /* Enter the interactive session. */
514: server_loop(pid, pin[1], pout[0], perr[0]);
1.64 markus 515: /* server_loop has closed pin[1], pout[0], and perr[0]. */
1.2 markus 516: }
1.1 markus 517: #else /* USE_PIPES */
518: /* We are the parent. Close the child sides of the socket pairs. */
519: close(inout[0]);
520: close(err[0]);
521:
522: /*
523: * Enter the interactive session. Note: server_loop must be able to
524: * handle the case that fdin and fdout are the same.
525: */
1.2 markus 526: if (compat20) {
1.64 markus 527: session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
1.2 markus 528: } else {
529: server_loop(pid, inout[1], inout[1], err[1]);
530: /* server_loop has closed inout[1] and err[1]. */
531: }
1.1 markus 532: #endif /* USE_PIPES */
533: }
534:
535: /*
536: * This is called to fork and execute a command when we have a tty. This
537: * will call do_child from the child, and server_loop from the parent after
538: * setting up file descriptors, controlling tty, updating wtmp, utmp,
539: * lastlog, and other such operations.
540: */
1.4 markus 541: void
1.63 markus 542: do_exec_pty(Session *s, const char *command)
1.1 markus 543: {
544: int fdout, ptyfd, ttyfd, ptymaster;
545: pid_t pid;
546:
547: if (s == NULL)
548: fatal("do_exec_pty: no session");
549: ptyfd = s->ptyfd;
550: ttyfd = s->ttyfd;
551:
552: /* Fork the child. */
553: if ((pid = fork()) == 0) {
1.144 markus 554: fatal_remove_all_cleanups();
1.97 markus 555:
1.24 markus 556: /* Child. Reinitialize the log because the pid has changed. */
1.1 markus 557: log_init(__progname, options.log_level, options.log_facility, log_stderr);
558: /* Close the master side of the pseudo tty. */
559: close(ptyfd);
560:
561: /* Make the pseudo tty our controlling tty. */
562: pty_make_controlling_tty(&ttyfd, s->tty);
563:
1.103 markus 564: /* Redirect stdin/stdout/stderr from the pseudo tty. */
565: if (dup2(ttyfd, 0) < 0)
566: error("dup2 stdin: %s", strerror(errno));
567: if (dup2(ttyfd, 1) < 0)
568: error("dup2 stdout: %s", strerror(errno));
569: if (dup2(ttyfd, 2) < 0)
570: error("dup2 stderr: %s", strerror(errno));
1.1 markus 571:
572: /* Close the extra descriptor for the pseudo tty. */
573: close(ttyfd);
574:
1.24 markus 575: /* record login, etc. similar to login(1) */
1.41 markus 576: if (!(options.use_login && command == NULL))
577: do_login(s, command);
1.1 markus 578:
579: /* Do common processing for the child, such as execing the command. */
1.60 markus 580: do_child(s, command);
1.1 markus 581: /* NOTREACHED */
582: }
583: if (pid < 0)
584: packet_disconnect("fork failed: %.100s", strerror(errno));
585: s->pid = pid;
586:
587: /* Parent. Close the slave side of the pseudo tty. */
588: close(ttyfd);
589:
590: /*
591: * Create another descriptor of the pty master side for use as the
592: * standard input. We could use the original descriptor, but this
593: * simplifies code in server_loop. The descriptor is bidirectional.
594: */
595: fdout = dup(ptyfd);
596: if (fdout < 0)
597: packet_disconnect("dup #1 failed: %.100s", strerror(errno));
598:
599: /* we keep a reference to the pty master */
600: ptymaster = dup(ptyfd);
601: if (ptymaster < 0)
602: packet_disconnect("dup #2 failed: %.100s", strerror(errno));
603: s->ptymaster = ptymaster;
604:
605: /* Enter interactive session. */
1.47 markus 606: packet_set_interactive(1);
1.2 markus 607: if (compat20) {
608: session_set_fds(s, ptyfd, fdout, -1);
609: } else {
610: server_loop(pid, ptyfd, fdout, -1);
611: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 612: }
613: }
614:
1.90 markus 615: /*
616: * This is called to fork and execute a command. If another command is
617: * to be forced, execute that instead.
618: */
619: void
620: do_exec(Session *s, const char *command)
621: {
622: if (forced_command) {
623: original_command = command;
624: command = forced_command;
625: debug("Forced command '%.900s'", command);
626: }
627:
628: if (s->ttyfd != -1)
629: do_exec_pty(s, command);
630: else
631: do_exec_no_pty(s, command);
632:
1.92 markus 633: original_command = NULL;
1.90 markus 634: }
635:
636:
1.24 markus 637: /* administrative, login(1)-like work */
638: void
1.41 markus 639: do_login(Session *s, const char *command)
1.24 markus 640: {
641: char *time_string;
642: socklen_t fromlen;
643: struct sockaddr_storage from;
644: struct passwd * pw = s->pw;
645: pid_t pid = getpid();
646:
647: /*
648: * Get IP address of client. If the connection is not a socket, let
649: * the address be 0.0.0.0.
650: */
651: memset(&from, 0, sizeof(from));
1.148 stevesk 652: fromlen = sizeof(from);
1.24 markus 653: if (packet_connection_is_on_socket()) {
654: if (getpeername(packet_get_connection_in(),
1.112 deraadt 655: (struct sockaddr *) & from, &fromlen) < 0) {
1.24 markus 656: debug("getpeername: %.100s", strerror(errno));
657: fatal_cleanup();
658: }
659: }
1.25 markus 660:
1.24 markus 661: /* Record that there was a login on that tty from the remote host. */
1.133 markus 662: if (!use_privsep)
663: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
664: get_remote_name_or_ip(utmp_len,
665: options.verify_reverse_mapping),
1.148 stevesk 666: (struct sockaddr *)&from, fromlen);
1.24 markus 667:
1.73 djm 668: if (check_quietlogin(s, command))
1.24 markus 669: return;
1.73 djm 670:
1.134 markus 671: if (options.print_lastlog && s->last_login_time != 0) {
672: time_string = ctime(&s->last_login_time);
1.24 markus 673: if (strchr(time_string, '\n'))
674: *strchr(time_string, '\n') = 0;
1.134 markus 675: if (strcmp(s->hostname, "") == 0)
1.24 markus 676: printf("Last login: %s\r\n", time_string);
677: else
1.134 markus 678: printf("Last login: %s from %s\r\n", time_string,
679: s->hostname);
1.24 markus 680: }
1.73 djm 681:
682: do_motd();
683: }
684:
685: /*
686: * Display the message of the day.
687: */
688: void
689: do_motd(void)
690: {
691: FILE *f;
692: char buf[256];
693:
1.24 markus 694: if (options.print_motd) {
1.28 millert 695: #ifdef HAVE_LOGIN_CAP
696: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
697: "/etc/motd"), "r");
698: #else
1.24 markus 699: f = fopen("/etc/motd", "r");
1.28 millert 700: #endif
1.24 markus 701: if (f) {
702: while (fgets(buf, sizeof(buf), f))
703: fputs(buf, stdout);
704: fclose(f);
705: }
1.2 markus 706: }
1.73 djm 707: }
708:
709:
710: /*
711: * Check for quiet login, either .hushlogin or command given.
712: */
713: int
714: check_quietlogin(Session *s, const char *command)
715: {
716: char buf[256];
1.96 dugsong 717: struct passwd *pw = s->pw;
1.73 djm 718: struct stat st;
719:
720: /* Return 1 if .hushlogin exists or a command given. */
721: if (command != NULL)
722: return 1;
723: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
724: #ifdef HAVE_LOGIN_CAP
725: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
726: return 1;
727: #else
728: if (stat(buf, &st) >= 0)
729: return 1;
730: #endif
731: return 0;
1.1 markus 732: }
733:
734: /*
735: * Sets the value of the given variable in the environment. If the variable
736: * already exists, its value is overriden.
737: */
1.94 itojun 738: static void
1.45 markus 739: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 740: const char *value)
1.1 markus 741: {
1.45 markus 742: u_int i, namelen;
1.1 markus 743: char **env;
744:
745: /*
746: * Find the slot where the value should be stored. If the variable
747: * already exists, we reuse the slot; otherwise we append a new slot
748: * at the end of the array, expanding if necessary.
749: */
750: env = *envp;
751: namelen = strlen(name);
752: for (i = 0; env[i]; i++)
753: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
754: break;
755: if (env[i]) {
756: /* Reuse the slot. */
757: xfree(env[i]);
758: } else {
759: /* New variable. Expand if necessary. */
760: if (i >= (*envsizep) - 1) {
1.141 markus 761: if (*envsizep >= 1000)
762: fatal("child_set_env: too many env vars,"
763: " skipping: %.100s", name);
1.1 markus 764: (*envsizep) += 50;
765: env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
766: }
767: /* Need to set the NULL pointer at end of array beyond the new slot. */
768: env[i + 1] = NULL;
769: }
770:
771: /* Allocate space and format the variable in the appropriate slot. */
772: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
773: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
774: }
775:
776: /*
777: * Reads environment variables from the given file and adds/overrides them
778: * into the environment. If the file does not exist, this does nothing.
779: * Otherwise, it must consist of empty lines, comments (line starts with '#')
780: * and assignments of the form name=value. No other forms are allowed.
781: */
1.94 itojun 782: static void
1.45 markus 783: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 784: const char *filename)
1.1 markus 785: {
786: FILE *f;
787: char buf[4096];
788: char *cp, *value;
1.142 deraadt 789: u_int lineno = 0;
1.1 markus 790:
791: f = fopen(filename, "r");
792: if (!f)
793: return;
794:
795: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 796: if (++lineno > 1000)
797: fatal("Too many lines in environment file %s", filename);
1.1 markus 798: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
799: ;
800: if (!*cp || *cp == '#' || *cp == '\n')
801: continue;
802: if (strchr(cp, '\n'))
803: *strchr(cp, '\n') = '\0';
804: value = strchr(cp, '=');
805: if (value == NULL) {
1.142 deraadt 806: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
807: filename);
1.1 markus 808: continue;
809: }
1.14 deraadt 810: /*
811: * Replace the equals sign by nul, and advance value to
812: * the value string.
813: */
1.1 markus 814: *value = '\0';
815: value++;
816: child_set_env(env, envsize, cp, value);
817: }
818: fclose(f);
819: }
820:
1.127 markus 821: static char **
822: do_setup_env(Session *s, const char *shell)
1.1 markus 823: {
824: char buf[256];
1.127 markus 825: u_int i, envsize;
1.1 markus 826: char **env;
1.127 markus 827: struct passwd *pw = s->pw;
1.1 markus 828:
829: /* Initialize the environment. */
830: envsize = 100;
831: env = xmalloc(envsize * sizeof(char *));
832: env[0] = NULL;
833:
834: if (!options.use_login) {
835: /* Set basic environment. */
836: child_set_env(&env, &envsize, "USER", pw->pw_name);
837: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
838: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.28 millert 839: #ifdef HAVE_LOGIN_CAP
1.145 markus 840: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
841: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
842: else
843: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.28 millert 844: #else
1.29 millert 845: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1.28 millert 846: #endif
1.1 markus 847:
848: snprintf(buf, sizeof buf, "%.200s/%.50s",
849: _PATH_MAILDIR, pw->pw_name);
850: child_set_env(&env, &envsize, "MAIL", buf);
851:
852: /* Normal systems set SHELL by default. */
853: child_set_env(&env, &envsize, "SHELL", shell);
854: }
855: if (getenv("TZ"))
856: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
857:
858: /* Set custom environment options from RSA authentication. */
1.110 markus 859: if (!options.use_login) {
860: while (custom_environment) {
861: struct envstring *ce = custom_environment;
1.143 deraadt 862: char *str = ce->s;
1.127 markus 863:
1.143 deraadt 864: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 865: ;
1.143 deraadt 866: if (str[i] == '=') {
867: str[i] = 0;
868: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 869: }
870: custom_environment = ce->next;
871: xfree(ce->s);
872: xfree(ce);
1.1 markus 873: }
874: }
875:
1.149 stevesk 876: /* SSH_CLIENT deprecated */
1.1 markus 877: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 878: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 879: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 880:
881: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
882: get_remote_ipaddr(), get_remote_port(),
883: get_local_ipaddr(packet_get_connection_in()), get_local_port());
884: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 885:
1.60 markus 886: if (s->ttyfd != -1)
887: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
888: if (s->term)
889: child_set_env(&env, &envsize, "TERM", s->term);
890: if (s->display)
891: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 892: if (original_command)
893: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
894: original_command);
1.1 markus 895: #ifdef KRB4
1.96 dugsong 896: if (s->authctxt->krb4_ticket_file)
897: child_set_env(&env, &envsize, "KRBTKFILE",
1.112 deraadt 898: s->authctxt->krb4_ticket_file);
1.96 dugsong 899: #endif
900: #ifdef KRB5
901: if (s->authctxt->krb5_ticket_file)
902: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 903: s->authctxt->krb5_ticket_file);
1.96 dugsong 904: #endif
1.136 markus 905: if (auth_sock_name != NULL)
1.1 markus 906: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 907: auth_sock_name);
1.1 markus 908:
909: /* read $HOME/.ssh/environment. */
1.146 markus 910: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 911: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
912: pw->pw_dir);
1.1 markus 913: read_environment_file(&env, &envsize, buf);
914: }
915: if (debug_flag) {
916: /* dump the environment */
917: fprintf(stderr, "Environment:\n");
918: for (i = 0; env[i]; i++)
919: fprintf(stderr, " %.200s\n", env[i]);
920: }
1.127 markus 921: return env;
922: }
923:
924: /*
925: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
926: * first in this order).
927: */
928: static void
929: do_rc_files(Session *s, const char *shell)
930: {
931: FILE *f = NULL;
932: char cmd[1024];
933: int do_xauth;
934: struct stat st;
935:
936: do_xauth =
937: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
938:
939: /* ignore _PATH_SSH_USER_RC for subsystems */
940: if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
941: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
942: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
943: if (debug_flag)
944: fprintf(stderr, "Running %s\n", cmd);
945: f = popen(cmd, "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_USER_RC);
954: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
955: if (debug_flag)
956: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
957: _PATH_SSH_SYSTEM_RC);
958: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
959: if (f) {
960: if (do_xauth)
961: fprintf(f, "%s %s\n", s->auth_proto,
962: s->auth_data);
963: pclose(f);
964: } else
965: fprintf(stderr, "Could not run %s\n",
966: _PATH_SSH_SYSTEM_RC);
967: } else if (do_xauth && options.xauth_location != NULL) {
968: /* Add authority data to .Xauthority if appropriate. */
969: if (debug_flag) {
970: fprintf(stderr,
1.151 stevesk 971: "Running %.500s remove %.100s\n",
972: options.xauth_location, s->auth_display);
973: fprintf(stderr,
974: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 975: options.xauth_location, s->auth_display,
976: s->auth_proto, s->auth_data);
977: }
978: snprintf(cmd, sizeof cmd, "%s -q -",
979: options.xauth_location);
980: f = popen(cmd, "w");
981: if (f) {
1.151 stevesk 982: fprintf(f, "remove %s\n",
983: s->auth_display);
1.127 markus 984: fprintf(f, "add %s %s %s\n",
985: s->auth_display, s->auth_proto,
986: s->auth_data);
987: pclose(f);
988: } else {
989: fprintf(stderr, "Could not run %s\n",
990: cmd);
991: }
992: }
993: }
994:
995: static void
996: do_nologin(struct passwd *pw)
997: {
998: FILE *f = NULL;
999: char buf[1024];
1000:
1001: #ifdef HAVE_LOGIN_CAP
1002: if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1003: f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1004: _PATH_NOLOGIN), "r");
1005: #else
1006: if (pw->pw_uid)
1007: f = fopen(_PATH_NOLOGIN, "r");
1008: #endif
1009: if (f) {
1010: /* /etc/nologin exists. Print its contents and exit. */
1.150 stevesk 1011: log("User %.100s not allowed because %s exists",
1012: pw->pw_name, _PATH_NOLOGIN);
1.127 markus 1013: while (fgets(buf, sizeof(buf), f))
1014: fputs(buf, stderr);
1015: fclose(f);
1016: exit(254);
1017: }
1018: }
1019:
1020: /* Set login name, uid, gid, and groups. */
1.130 provos 1021: void
1.127 markus 1022: do_setusercontext(struct passwd *pw)
1023: {
1024: if (getuid() == 0 || geteuid() == 0) {
1025: #ifdef HAVE_LOGIN_CAP
1026: if (setusercontext(lc, pw, pw->pw_uid,
1027: (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1028: perror("unable to set user context");
1029: exit(1);
1030: }
1031: #else
1032: if (setlogin(pw->pw_name) < 0)
1033: error("setlogin failed: %s", strerror(errno));
1034: if (setgid(pw->pw_gid) < 0) {
1035: perror("setgid");
1036: exit(1);
1037: }
1038: /* Initialize the group list. */
1039: if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1040: perror("initgroups");
1041: exit(1);
1042: }
1043: endgrent();
1044:
1045: /* Permanently switch to the desired uid. */
1046: permanently_set_uid(pw);
1047: #endif
1048: }
1049: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1050: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1051: }
1052:
1.131 markus 1053: static void
1.130 provos 1054: launch_login(struct passwd *pw, const char *hostname)
1055: {
1056: /* Launch login(1). */
1057:
1058: execl("/usr/bin/login", "login", "-h", hostname,
1059: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1060:
1061: /* Login couldn't be executed, die. */
1062:
1063: perror("login");
1064: exit(1);
1065: }
1066:
1.127 markus 1067: /*
1068: * Performs common processing for the child, such as setting up the
1069: * environment, closing extra file descriptors, setting the user and group
1070: * ids, and executing the command or shell.
1071: */
1072: void
1073: do_child(Session *s, const char *command)
1074: {
1075: extern char **environ;
1076: char **env;
1077: char *argv[10];
1078: const char *shell, *shell0, *hostname = NULL;
1079: struct passwd *pw = s->pw;
1080: u_int i;
1081:
1082: /* remove hostkey from the child's memory */
1083: destroy_sensitive_data();
1084:
1085: /* login(1) is only called if we execute the login shell */
1086: if (options.use_login && command != NULL)
1087: options.use_login = 0;
1088:
1089: /*
1090: * Login(1) does this as well, and it needs uid 0 for the "-h"
1091: * switch, so we let login(1) to this for us.
1092: */
1093: if (!options.use_login) {
1094: do_nologin(pw);
1095: do_setusercontext(pw);
1096: }
1097:
1098: /*
1099: * Get the shell from the password data. An empty shell field is
1100: * legal, and means /bin/sh.
1101: */
1102: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1103:
1104: /*
1105: * Make sure $SHELL points to the shell from the password file,
1106: * even if shell is overridden from login.conf
1107: */
1108: env = do_setup_env(s, shell);
1109:
1.127 markus 1110: #ifdef HAVE_LOGIN_CAP
1111: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1112: #endif
1113:
1.26 millert 1114: /* we have to stash the hostname before we close our socket. */
1115: if (options.use_login)
1.70 stevesk 1116: hostname = get_remote_name_or_ip(utmp_len,
1.120 markus 1117: options.verify_reverse_mapping);
1.1 markus 1118: /*
1119: * Close the connection descriptors; note that this is the child, and
1120: * the server will still have the socket open, and it is important
1121: * that we do not shutdown it. Note that the descriptors cannot be
1122: * closed before building the environment, as we call
1123: * get_remote_ipaddr there.
1124: */
1125: if (packet_get_connection_in() == packet_get_connection_out())
1126: close(packet_get_connection_in());
1127: else {
1128: close(packet_get_connection_in());
1129: close(packet_get_connection_out());
1130: }
1131: /*
1132: * Close all descriptors related to channels. They will still remain
1133: * open in the parent.
1134: */
1135: /* XXX better use close-on-exec? -markus */
1136: channel_close_all();
1137:
1138: /*
1139: * Close any extra file descriptors. Note that there may still be
1140: * descriptors left by system functions. They will be closed later.
1141: */
1142: endpwent();
1143:
1144: /*
1145: * Close any extra open file descriptors so that we don\'t have them
1146: * hanging around in clients. Note that we want to do this after
1147: * initgroups, because at least on Solaris 2.3 it leaves file
1148: * descriptors open.
1149: */
1150: for (i = 3; i < 64; i++)
1151: close(i);
1152:
1153: /*
1.125 deraadt 1154: * Must take new environment into use so that .ssh/rc,
1155: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1156: */
1157: environ = env;
1.102 markus 1158:
1159: #ifdef AFS
1160: /* Try to get AFS tokens for the local cell. */
1161: if (k_hasafs()) {
1162: char cell[64];
1.112 deraadt 1163:
1.102 markus 1164: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1165: krb_afslog(cell, 0);
1.112 deraadt 1166:
1.102 markus 1167: krb_afslog(0, 0);
1168: }
1169: #endif /* AFS */
1.104 markus 1170:
1171: /* Change current directory to the user\'s home directory. */
1172: if (chdir(pw->pw_dir) < 0) {
1173: fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1174: pw->pw_dir, strerror(errno));
1175: #ifdef HAVE_LOGIN_CAP
1176: if (login_getcapbool(lc, "requirehome", 0))
1177: exit(1);
1178: #endif
1179: }
1.1 markus 1180:
1.127 markus 1181: if (!options.use_login)
1182: do_rc_files(s, shell);
1.67 markus 1183:
1184: /* restore SIGPIPE for child */
1185: signal(SIGPIPE, SIG_DFL);
1186:
1.127 markus 1187: if (options.use_login) {
1.130 provos 1188: launch_login(pw, hostname);
1189: /* NEVERREACHED */
1.127 markus 1190: }
1191:
1192: /* Get the last component of the shell name. */
1193: if ((shell0 = strrchr(shell, '/')) != NULL)
1194: shell0++;
1195: else
1196: shell0 = shell;
1197:
1.1 markus 1198: /*
1199: * If we have no command, execute the shell. In this case, the shell
1200: * name to be passed in argv[0] is preceded by '-' to indicate that
1201: * this is a login shell.
1202: */
1203: if (!command) {
1.127 markus 1204: char argv0[256];
1.1 markus 1205:
1.127 markus 1206: /* Start the shell. Set initial character to '-'. */
1207: argv0[0] = '-';
1.1 markus 1208:
1.127 markus 1209: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1210: >= sizeof(argv0) - 1) {
1.127 markus 1211: errno = EINVAL;
1.1 markus 1212: perror(shell);
1213: exit(1);
1.127 markus 1214: }
1.1 markus 1215:
1.127 markus 1216: /* Execute the shell. */
1217: argv[0] = argv0;
1218: argv[1] = NULL;
1219: execve(shell, argv, env);
1220:
1221: /* Executing the shell failed. */
1222: perror(shell);
1223: exit(1);
1.1 markus 1224: }
1225: /*
1226: * Execute the command using the user's shell. This uses the -c
1227: * option to execute the command.
1228: */
1.127 markus 1229: argv[0] = (char *) shell0;
1.1 markus 1230: argv[1] = "-c";
1231: argv[2] = (char *) command;
1232: argv[3] = NULL;
1233: execve(shell, argv, env);
1234: perror(shell);
1235: exit(1);
1236: }
1237:
1238: Session *
1239: session_new(void)
1240: {
1241: int i;
1242: static int did_init = 0;
1243: if (!did_init) {
1244: debug("session_new: init");
1.112 deraadt 1245: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1246: sessions[i].used = 0;
1247: }
1248: did_init = 1;
1249: }
1.112 deraadt 1250: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1251: Session *s = &sessions[i];
1252: if (! s->used) {
1.68 djm 1253: memset(s, 0, sizeof(*s));
1.1 markus 1254: s->chanid = -1;
1255: s->ptyfd = -1;
1256: s->ttyfd = -1;
1257: s->used = 1;
1.85 markus 1258: s->self = i;
1.1 markus 1259: debug("session_new: session %d", i);
1260: return s;
1261: }
1262: }
1263: return NULL;
1264: }
1265:
1.94 itojun 1266: static void
1.1 markus 1267: session_dump(void)
1268: {
1269: int i;
1.112 deraadt 1270: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1271: Session *s = &sessions[i];
1.137 mpech 1272: debug("dump: used %d session %d %p channel %d pid %ld",
1.1 markus 1273: s->used,
1274: s->self,
1275: s,
1276: s->chanid,
1.137 mpech 1277: (long)s->pid);
1.1 markus 1278: }
1279: }
1280:
1.2 markus 1281: int
1.97 markus 1282: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1283: {
1284: Session *s = session_new();
1285: debug("session_open: channel %d", chanid);
1286: if (s == NULL) {
1287: error("no more sessions");
1288: return 0;
1289: }
1.97 markus 1290: s->authctxt = authctxt;
1291: s->pw = authctxt->pw;
1.7 markus 1292: if (s->pw == NULL)
1.54 stevesk 1293: fatal("no user for session %d", s->self);
1.2 markus 1294: debug("session_open: session %d: link with channel %d", s->self, chanid);
1295: s->chanid = chanid;
1296: return 1;
1297: }
1298:
1.130 provos 1299: Session *
1300: session_by_tty(char *tty)
1301: {
1302: int i;
1303: for (i = 0; i < MAX_SESSIONS; i++) {
1304: Session *s = &sessions[i];
1305: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1306: debug("session_by_tty: session %d tty %s", i, tty);
1307: return s;
1308: }
1309: }
1310: debug("session_by_tty: unknown tty %.100s", tty);
1311: session_dump();
1312: return NULL;
1313: }
1314:
1.94 itojun 1315: static Session *
1.2 markus 1316: session_by_channel(int id)
1317: {
1318: int i;
1.112 deraadt 1319: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1320: Session *s = &sessions[i];
1321: if (s->used && s->chanid == id) {
1322: debug("session_by_channel: session %d channel %d", i, id);
1323: return s;
1324: }
1325: }
1326: debug("session_by_channel: unknown channel %d", id);
1327: session_dump();
1328: return NULL;
1329: }
1330:
1.94 itojun 1331: static Session *
1.2 markus 1332: session_by_pid(pid_t pid)
1333: {
1334: int i;
1.137 mpech 1335: debug("session_by_pid: pid %ld", (long)pid);
1.112 deraadt 1336: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1337: Session *s = &sessions[i];
1338: if (s->used && s->pid == pid)
1339: return s;
1340: }
1.137 mpech 1341: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1342: session_dump();
1343: return NULL;
1344: }
1345:
1.94 itojun 1346: static int
1.2 markus 1347: session_window_change_req(Session *s)
1348: {
1349: s->col = packet_get_int();
1350: s->row = packet_get_int();
1351: s->xpixel = packet_get_int();
1352: s->ypixel = packet_get_int();
1.116 markus 1353: packet_check_eom();
1.2 markus 1354: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1355: return 1;
1356: }
1357:
1.94 itojun 1358: static int
1.2 markus 1359: session_pty_req(Session *s)
1360: {
1.45 markus 1361: u_int len;
1.72 stevesk 1362: int n_bytes;
1.132 markus 1363:
1.86 markus 1364: if (no_pty_flag) {
1365: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1366: return 0;
1.86 markus 1367: }
1368: if (s->ttyfd != -1) {
1369: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1370: return 0;
1.134 markus 1371: }
1372: /* Get the time and hostname when the user last logged in. */
1373: if (options.print_lastlog) {
1374: s->hostname[0] = '\0';
1375: s->last_login_time = get_last_login_time(s->pw->pw_uid,
1376: s->pw->pw_name, s->hostname, sizeof(s->hostname));
1.86 markus 1377: }
1378:
1.2 markus 1379: s->term = packet_get_string(&len);
1.86 markus 1380:
1381: if (compat20) {
1382: s->col = packet_get_int();
1383: s->row = packet_get_int();
1384: } else {
1385: s->row = packet_get_int();
1386: s->col = packet_get_int();
1387: }
1.2 markus 1388: s->xpixel = packet_get_int();
1389: s->ypixel = packet_get_int();
1390:
1391: if (strcmp(s->term, "") == 0) {
1392: xfree(s->term);
1393: s->term = NULL;
1394: }
1.86 markus 1395:
1.2 markus 1396: /* Allocate a pty and open it. */
1.86 markus 1397: debug("Allocating pty.");
1.130 provos 1398: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1.86 markus 1399: if (s->term)
1400: xfree(s->term);
1.2 markus 1401: s->term = NULL;
1402: s->ptyfd = -1;
1403: s->ttyfd = -1;
1404: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1405: return 0;
1.2 markus 1406: }
1407: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1408:
1409: /* for SSH1 the tty modes length is not given */
1410: if (!compat20)
1411: n_bytes = packet_remaining();
1412: tty_parse_modes(s->ttyfd, &n_bytes);
1413:
1.2 markus 1414: /*
1415: * Add a cleanup function to clear the utmp entry and record logout
1416: * time in case we call fatal() (e.g., the connection gets closed).
1417: */
1.85 markus 1418: fatal_add_cleanup(session_pty_cleanup, (void *)s);
1.130 provos 1419: if (!use_privsep)
1420: pty_setowner(s->pw, s->tty);
1.86 markus 1421:
1422: /* Set window size from the packet. */
1.2 markus 1423: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1424:
1.116 markus 1425: packet_check_eom();
1.9 markus 1426: session_proctitle(s);
1.2 markus 1427: return 1;
1428: }
1429:
1.94 itojun 1430: static int
1.7 markus 1431: session_subsystem_req(Session *s)
1432: {
1.105 markus 1433: struct stat st;
1.45 markus 1434: u_int len;
1.7 markus 1435: int success = 0;
1.105 markus 1436: char *cmd, *subsys = packet_get_string(&len);
1.18 jakob 1437: int i;
1.7 markus 1438:
1.116 markus 1439: packet_check_eom();
1.121 stevesk 1440: log("subsystem request for %.100s", subsys);
1.18 jakob 1441:
1442: for (i = 0; i < options.num_subsystems; i++) {
1.105 markus 1443: if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1444: cmd = options.subsystem_command[i];
1445: if (stat(cmd, &st) < 0) {
1446: error("subsystem: cannot stat %s: %s", cmd,
1447: strerror(errno));
1448: break;
1449: }
1450: debug("subsystem: exec() %s", cmd);
1.64 markus 1451: s->is_subsystem = 1;
1.105 markus 1452: do_exec(s, cmd);
1.18 jakob 1453: success = 1;
1.122 markus 1454: break;
1.18 jakob 1455: }
1456: }
1457:
1458: if (!success)
1.121 stevesk 1459: log("subsystem request for %.100s failed, subsystem not found",
1.105 markus 1460: subsys);
1.7 markus 1461:
1462: xfree(subsys);
1463: return success;
1464: }
1465:
1.94 itojun 1466: static int
1.7 markus 1467: session_x11_req(Session *s)
1468: {
1.81 markus 1469: int success;
1.7 markus 1470:
1471: s->single_connection = packet_get_char();
1472: s->auth_proto = packet_get_string(NULL);
1473: s->auth_data = packet_get_string(NULL);
1474: s->screen = packet_get_int();
1.116 markus 1475: packet_check_eom();
1.7 markus 1476:
1.81 markus 1477: success = session_setup_x11fwd(s);
1478: if (!success) {
1.7 markus 1479: xfree(s->auth_proto);
1480: xfree(s->auth_data);
1.84 markus 1481: s->auth_proto = NULL;
1482: s->auth_data = NULL;
1.7 markus 1483: }
1.81 markus 1484: return success;
1.7 markus 1485: }
1486:
1.94 itojun 1487: static int
1.19 markus 1488: session_shell_req(Session *s)
1489: {
1.116 markus 1490: packet_check_eom();
1.90 markus 1491: do_exec(s, NULL);
1.19 markus 1492: return 1;
1493: }
1494:
1.94 itojun 1495: static int
1.19 markus 1496: session_exec_req(Session *s)
1497: {
1.45 markus 1498: u_int len;
1.19 markus 1499: char *command = packet_get_string(&len);
1.116 markus 1500: packet_check_eom();
1.90 markus 1501: do_exec(s, command);
1.92 markus 1502: xfree(command);
1.19 markus 1503: return 1;
1504: }
1505:
1.94 itojun 1506: static int
1.43 markus 1507: session_auth_agent_req(Session *s)
1508: {
1509: static int called = 0;
1.116 markus 1510: packet_check_eom();
1.44 markus 1511: if (no_agent_forwarding_flag) {
1512: debug("session_auth_agent_req: no_agent_forwarding_flag");
1513: return 0;
1514: }
1.43 markus 1515: if (called) {
1516: return 0;
1517: } else {
1518: called = 1;
1519: return auth_input_request_forwarding(s->pw);
1520: }
1521: }
1522:
1.123 markus 1523: int
1524: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1525: {
1526: int success = 0;
1527: Session *s;
1528:
1.123 markus 1529: if ((s = session_by_channel(c->self)) == NULL) {
1530: log("session_input_channel_req: no session %d req %.100s",
1531: c->self, rtype);
1532: return 0;
1533: }
1534: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1535:
1536: /*
1.64 markus 1537: * a session is in LARVAL state until a shell, a command
1538: * or a subsystem is executed
1.2 markus 1539: */
1540: if (c->type == SSH_CHANNEL_LARVAL) {
1541: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1542: success = session_shell_req(s);
1.2 markus 1543: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1544: success = session_exec_req(s);
1.2 markus 1545: } else if (strcmp(rtype, "pty-req") == 0) {
1.3 markus 1546: success = session_pty_req(s);
1.7 markus 1547: } else if (strcmp(rtype, "x11-req") == 0) {
1548: success = session_x11_req(s);
1.43 markus 1549: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1550: success = session_auth_agent_req(s);
1.7 markus 1551: } else if (strcmp(rtype, "subsystem") == 0) {
1552: success = session_subsystem_req(s);
1.2 markus 1553: }
1554: }
1555: if (strcmp(rtype, "window-change") == 0) {
1556: success = session_window_change_req(s);
1557: }
1.123 markus 1558: return success;
1.2 markus 1559: }
1560:
1561: void
1562: session_set_fds(Session *s, int fdin, int fdout, int fderr)
1563: {
1564: if (!compat20)
1565: fatal("session_set_fds: called for proto != 2.0");
1566: /*
1567: * now that have a child and a pipe to the child,
1568: * we can activate our channel and register the fd's
1569: */
1570: if (s->chanid == -1)
1571: fatal("no channel for session %d", s->self);
1572: channel_set_fds(s->chanid,
1573: fdout, fdin, fderr,
1.42 markus 1574: fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.126 markus 1575: 1,
1576: CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1577: }
1578:
1.85 markus 1579: /*
1580: * Function to perform pty cleanup. Also called if we get aborted abnormally
1581: * (e.g., due to a dropped connection).
1582: */
1.130 provos 1583: void
1584: session_pty_cleanup2(void *session)
1.1 markus 1585: {
1.85 markus 1586: Session *s = session;
1587:
1588: if (s == NULL) {
1589: error("session_pty_cleanup: no session");
1590: return;
1591: }
1592: if (s->ttyfd == -1)
1.1 markus 1593: return;
1594:
1.54 stevesk 1595: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1596:
1597: /* Record that the user has logged out. */
1.85 markus 1598: if (s->pid != 0)
1599: record_logout(s->pid, s->tty);
1.1 markus 1600:
1601: /* Release the pseudo-tty. */
1.130 provos 1602: if (getuid() == 0)
1603: pty_release(s->tty);
1.1 markus 1604:
1605: /*
1606: * Close the server side of the socket pairs. We must do this after
1607: * the pty cleanup, so that another process doesn't get this pty
1608: * while we're still cleaning up.
1609: */
1610: if (close(s->ptymaster) < 0)
1.130 provos 1611: error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1.108 markus 1612:
1613: /* unlink pty from session */
1614: s->ttyfd = -1;
1.2 markus 1615: }
1616:
1.130 provos 1617: void
1618: session_pty_cleanup(void *session)
1619: {
1620: PRIVSEP(session_pty_cleanup2(session));
1621: }
1622:
1.147 markus 1623: static char *
1624: sig2name(int sig)
1625: {
1626: #define SSH_SIG(x) if (sig == SIG ## x) return #x
1627: SSH_SIG(ABRT);
1628: SSH_SIG(ALRM);
1629: SSH_SIG(FPE);
1630: SSH_SIG(HUP);
1631: SSH_SIG(ILL);
1632: SSH_SIG(INT);
1633: SSH_SIG(KILL);
1634: SSH_SIG(PIPE);
1635: SSH_SIG(QUIT);
1636: SSH_SIG(SEGV);
1637: SSH_SIG(TERM);
1638: SSH_SIG(USR1);
1639: SSH_SIG(USR2);
1640: #undef SSH_SIG
1641: return "SIG@openssh.com";
1642: }
1643:
1.94 itojun 1644: static void
1.2 markus 1645: session_exit_message(Session *s, int status)
1646: {
1647: Channel *c;
1.124 markus 1648:
1649: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 1650: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 1651: s->self, s->chanid);
1.137 mpech 1652: debug("session_exit_message: session %d channel %d pid %ld",
1653: s->self, s->chanid, (long)s->pid);
1.2 markus 1654:
1655: if (WIFEXITED(status)) {
1.124 markus 1656: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 1657: packet_put_int(WEXITSTATUS(status));
1658: packet_send();
1659: } else if (WIFSIGNALED(status)) {
1.124 markus 1660: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 1661: packet_put_cstring(sig2name(WTERMSIG(status)));
1.2 markus 1662: packet_put_char(WCOREDUMP(status));
1663: packet_put_cstring("");
1664: packet_put_cstring("");
1665: packet_send();
1666: } else {
1667: /* Some weird exit cause. Just exit. */
1668: packet_disconnect("wait returned status %04x.", status);
1669: }
1670:
1671: /* disconnect channel */
1672: debug("session_exit_message: release channel %d", s->chanid);
1673: channel_cancel_cleanup(s->chanid);
1.5 markus 1674: /*
1675: * emulate a write failure with 'chan_write_failed', nobody will be
1676: * interested in data we write.
1677: * Note that we must not call 'chan_read_failed', since there could
1678: * be some more data waiting in the pipe.
1679: */
1.8 markus 1680: if (c->ostate != CHAN_OUTPUT_CLOSED)
1681: chan_write_failed(c);
1.2 markus 1682: s->chanid = -1;
1683: }
1684:
1.130 provos 1685: void
1.85 markus 1686: session_close(Session *s)
1.2 markus 1687: {
1.137 mpech 1688: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.85 markus 1689: if (s->ttyfd != -1) {
1690: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1691: session_pty_cleanup(s);
1692: }
1.2 markus 1693: if (s->term)
1694: xfree(s->term);
1695: if (s->display)
1696: xfree(s->display);
1.118 stevesk 1697: if (s->auth_display)
1698: xfree(s->auth_display);
1.2 markus 1699: if (s->auth_data)
1700: xfree(s->auth_data);
1701: if (s->auth_proto)
1702: xfree(s->auth_proto);
1703: s->used = 0;
1.9 markus 1704: session_proctitle(s);
1.2 markus 1705: }
1706:
1707: void
1708: session_close_by_pid(pid_t pid, int status)
1709: {
1710: Session *s = session_by_pid(pid);
1711: if (s == NULL) {
1.137 mpech 1712: debug("session_close_by_pid: no session for pid %ld",
1713: (long)pid);
1.2 markus 1714: return;
1715: }
1716: if (s->chanid != -1)
1717: session_exit_message(s, status);
1718: session_close(s);
1.98 markus 1719: }
1720:
1.2 markus 1721: /*
1722: * this is called when a channel dies before
1723: * the session 'child' itself dies
1724: */
1725: void
1726: session_close_by_channel(int id, void *arg)
1727: {
1728: Session *s = session_by_channel(id);
1729: if (s == NULL) {
1.107 markus 1730: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 1731: return;
1732: }
1.137 mpech 1733: debug("session_close_by_channel: channel %d child %ld",
1734: id, (long)s->pid);
1.107 markus 1735: if (s->pid != 0) {
1736: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 1737: /*
1738: * delay detach of session, but release pty, since
1739: * the fd's to the child are already closed
1740: */
1741: if (s->ttyfd != -1) {
1742: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1743: session_pty_cleanup(s);
1744: }
1.107 markus 1745: return;
1746: }
1747: /* detach by removing callback */
1.2 markus 1748: channel_cancel_cleanup(s->chanid);
1749: s->chanid = -1;
1.106 markus 1750: session_close(s);
1751: }
1752:
1753: void
1.130 provos 1754: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 1755: {
1756: int i;
1.112 deraadt 1757: for (i = 0; i < MAX_SESSIONS; i++) {
1.106 markus 1758: Session *s = &sessions[i];
1.130 provos 1759: if (s->used) {
1760: if (closefunc != NULL)
1761: closefunc(s);
1762: else
1763: session_close(s);
1764: }
1.2 markus 1765: }
1.9 markus 1766: }
1767:
1.94 itojun 1768: static char *
1.9 markus 1769: session_tty_list(void)
1770: {
1771: static char buf[1024];
1772: int i;
1773: buf[0] = '\0';
1.112 deraadt 1774: for (i = 0; i < MAX_SESSIONS; i++) {
1.9 markus 1775: Session *s = &sessions[i];
1776: if (s->used && s->ttyfd != -1) {
1777: if (buf[0] != '\0')
1778: strlcat(buf, ",", sizeof buf);
1779: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1780: }
1781: }
1782: if (buf[0] == '\0')
1783: strlcpy(buf, "notty", sizeof buf);
1784: return buf;
1785: }
1786:
1787: void
1788: session_proctitle(Session *s)
1789: {
1790: if (s->pw == NULL)
1791: error("no user for session %d", s->self);
1792: else
1793: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 1794: }
1795:
1796: int
1797: session_setup_x11fwd(Session *s)
1798: {
1799: struct stat st;
1.109 stevesk 1800: char display[512], auth_display[512];
1801: char hostname[MAXHOSTNAMELEN];
1.81 markus 1802:
1803: if (no_x11_forwarding_flag) {
1804: packet_send_debug("X11 forwarding disabled in user configuration file.");
1805: return 0;
1806: }
1807: if (!options.x11_forwarding) {
1808: debug("X11 forwarding disabled in server configuration file.");
1809: return 0;
1810: }
1811: if (!options.xauth_location ||
1812: (stat(options.xauth_location, &st) == -1)) {
1813: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 1814: return 0;
1815: }
1816: if (options.use_login) {
1817: packet_send_debug("X11 forwarding disabled; "
1818: "not compatible with UseLogin=yes.");
1.81 markus 1819: return 0;
1820: }
1.87 markus 1821: if (s->display != NULL) {
1.81 markus 1822: debug("X11 display already set.");
1823: return 0;
1824: }
1.140 deraadt 1825: if (x11_create_display_inet(options.x11_display_offset,
1826: options.x11_use_localhost, s->single_connection,
1827: &s->display_number) == -1) {
1.87 markus 1828: debug("x11_create_display_inet failed.");
1.81 markus 1829: return 0;
1830: }
1.109 stevesk 1831:
1832: /* Set up a suitable value for the DISPLAY variable. */
1833: if (gethostname(hostname, sizeof(hostname)) < 0)
1834: fatal("gethostname: %.100s", strerror(errno));
1835: /*
1836: * auth_display must be used as the displayname when the
1837: * authorization entry is added with xauth(1). This will be
1838: * different than the DISPLAY string for localhost displays.
1839: */
1.119 stevesk 1840: if (options.x11_use_localhost) {
1.140 deraadt 1841: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 1842: s->display_number, s->screen);
1.140 deraadt 1843: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 1844: s->display_number, s->screen);
1.109 stevesk 1845: s->display = xstrdup(display);
1.118 stevesk 1846: s->auth_display = xstrdup(auth_display);
1.109 stevesk 1847: } else {
1.140 deraadt 1848: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 1849: s->display_number, s->screen);
1850: s->display = xstrdup(display);
1.118 stevesk 1851: s->auth_display = xstrdup(display);
1.109 stevesk 1852: }
1853:
1.81 markus 1854: return 1;
1.2 markus 1855: }
1856:
1.94 itojun 1857: static void
1.49 markus 1858: do_authenticated2(Authctxt *authctxt)
1.2 markus 1859: {
1.97 markus 1860: server_loop2(authctxt);
1.1 markus 1861: }
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