Annotation of src/usr.bin/ssh/session.c, Revision 1.157
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"
1.157 ! markus 36: RCSID("$OpenBSD: session.c,v 1.156 2003/05/11 20:30:25 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,
1.156 markus 182: 0, "auth socket", 1);
1.136 markus 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: */
1.155 itojun 401: logit("Unknown packet type received after authentication: %d", type);
1.1 markus 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;
1.154 markus 826: char **env, *laddr;
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:
1.154 markus 881: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 882: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 883: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
884: xfree(laddr);
1.149 stevesk 885: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 886:
1.60 markus 887: if (s->ttyfd != -1)
888: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
889: if (s->term)
890: child_set_env(&env, &envsize, "TERM", s->term);
891: if (s->display)
892: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 893: if (original_command)
894: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
895: original_command);
1.1 markus 896: #ifdef KRB4
1.96 dugsong 897: if (s->authctxt->krb4_ticket_file)
898: child_set_env(&env, &envsize, "KRBTKFILE",
1.112 deraadt 899: s->authctxt->krb4_ticket_file);
1.96 dugsong 900: #endif
901: #ifdef KRB5
902: if (s->authctxt->krb5_ticket_file)
903: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 904: s->authctxt->krb5_ticket_file);
1.96 dugsong 905: #endif
1.136 markus 906: if (auth_sock_name != NULL)
1.1 markus 907: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 908: auth_sock_name);
1.1 markus 909:
910: /* read $HOME/.ssh/environment. */
1.146 markus 911: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 912: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
913: pw->pw_dir);
1.1 markus 914: read_environment_file(&env, &envsize, buf);
915: }
916: if (debug_flag) {
917: /* dump the environment */
918: fprintf(stderr, "Environment:\n");
919: for (i = 0; env[i]; i++)
920: fprintf(stderr, " %.200s\n", env[i]);
921: }
1.127 markus 922: return env;
923: }
924:
925: /*
926: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
927: * first in this order).
928: */
929: static void
930: do_rc_files(Session *s, const char *shell)
931: {
932: FILE *f = NULL;
933: char cmd[1024];
934: int do_xauth;
935: struct stat st;
936:
937: do_xauth =
938: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
939:
940: /* ignore _PATH_SSH_USER_RC for subsystems */
941: if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
942: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
943: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
944: if (debug_flag)
945: fprintf(stderr, "Running %s\n", cmd);
946: f = popen(cmd, "w");
947: if (f) {
948: if (do_xauth)
949: fprintf(f, "%s %s\n", s->auth_proto,
950: s->auth_data);
951: pclose(f);
952: } else
953: fprintf(stderr, "Could not run %s\n",
954: _PATH_SSH_USER_RC);
955: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
956: if (debug_flag)
957: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
958: _PATH_SSH_SYSTEM_RC);
959: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
960: if (f) {
961: if (do_xauth)
962: fprintf(f, "%s %s\n", s->auth_proto,
963: s->auth_data);
964: pclose(f);
965: } else
966: fprintf(stderr, "Could not run %s\n",
967: _PATH_SSH_SYSTEM_RC);
968: } else if (do_xauth && options.xauth_location != NULL) {
969: /* Add authority data to .Xauthority if appropriate. */
970: if (debug_flag) {
971: fprintf(stderr,
1.151 stevesk 972: "Running %.500s remove %.100s\n",
973: options.xauth_location, s->auth_display);
974: fprintf(stderr,
975: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 976: options.xauth_location, s->auth_display,
977: s->auth_proto, s->auth_data);
978: }
979: snprintf(cmd, sizeof cmd, "%s -q -",
980: options.xauth_location);
981: f = popen(cmd, "w");
982: if (f) {
1.151 stevesk 983: fprintf(f, "remove %s\n",
984: s->auth_display);
1.127 markus 985: fprintf(f, "add %s %s %s\n",
986: s->auth_display, s->auth_proto,
987: s->auth_data);
988: pclose(f);
989: } else {
990: fprintf(stderr, "Could not run %s\n",
991: cmd);
992: }
993: }
994: }
995:
996: static void
997: do_nologin(struct passwd *pw)
998: {
999: FILE *f = NULL;
1000: char buf[1024];
1001:
1002: #ifdef HAVE_LOGIN_CAP
1003: if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1004: f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1005: _PATH_NOLOGIN), "r");
1006: #else
1007: if (pw->pw_uid)
1008: f = fopen(_PATH_NOLOGIN, "r");
1009: #endif
1010: if (f) {
1011: /* /etc/nologin exists. Print its contents and exit. */
1.155 itojun 1012: logit("User %.100s not allowed because %s exists",
1.150 stevesk 1013: pw->pw_name, _PATH_NOLOGIN);
1.127 markus 1014: while (fgets(buf, sizeof(buf), f))
1015: fputs(buf, stderr);
1016: fclose(f);
1017: exit(254);
1018: }
1019: }
1020:
1021: /* Set login name, uid, gid, and groups. */
1.130 provos 1022: void
1.127 markus 1023: do_setusercontext(struct passwd *pw)
1024: {
1025: if (getuid() == 0 || geteuid() == 0) {
1026: #ifdef HAVE_LOGIN_CAP
1027: if (setusercontext(lc, pw, pw->pw_uid,
1028: (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1029: perror("unable to set user context");
1030: exit(1);
1031: }
1032: #else
1033: if (setlogin(pw->pw_name) < 0)
1034: error("setlogin failed: %s", strerror(errno));
1035: if (setgid(pw->pw_gid) < 0) {
1036: perror("setgid");
1037: exit(1);
1038: }
1039: /* Initialize the group list. */
1040: if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1041: perror("initgroups");
1042: exit(1);
1043: }
1044: endgrent();
1045:
1046: /* Permanently switch to the desired uid. */
1047: permanently_set_uid(pw);
1048: #endif
1049: }
1050: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1051: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1052: }
1053:
1.131 markus 1054: static void
1.130 provos 1055: launch_login(struct passwd *pw, const char *hostname)
1056: {
1057: /* Launch login(1). */
1058:
1059: execl("/usr/bin/login", "login", "-h", hostname,
1060: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1061:
1062: /* Login couldn't be executed, die. */
1063:
1064: perror("login");
1065: exit(1);
1066: }
1067:
1.127 markus 1068: /*
1069: * Performs common processing for the child, such as setting up the
1070: * environment, closing extra file descriptors, setting the user and group
1071: * ids, and executing the command or shell.
1072: */
1073: void
1074: do_child(Session *s, const char *command)
1075: {
1076: extern char **environ;
1077: char **env;
1078: char *argv[10];
1079: const char *shell, *shell0, *hostname = NULL;
1080: struct passwd *pw = s->pw;
1081: u_int i;
1082:
1083: /* remove hostkey from the child's memory */
1084: destroy_sensitive_data();
1085:
1086: /* login(1) is only called if we execute the login shell */
1087: if (options.use_login && command != NULL)
1088: options.use_login = 0;
1089:
1090: /*
1091: * Login(1) does this as well, and it needs uid 0 for the "-h"
1092: * switch, so we let login(1) to this for us.
1093: */
1094: if (!options.use_login) {
1095: do_nologin(pw);
1096: do_setusercontext(pw);
1097: }
1098:
1099: /*
1100: * Get the shell from the password data. An empty shell field is
1101: * legal, and means /bin/sh.
1102: */
1103: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1104:
1105: /*
1106: * Make sure $SHELL points to the shell from the password file,
1107: * even if shell is overridden from login.conf
1108: */
1109: env = do_setup_env(s, shell);
1110:
1.127 markus 1111: #ifdef HAVE_LOGIN_CAP
1112: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1113: #endif
1114:
1.26 millert 1115: /* we have to stash the hostname before we close our socket. */
1116: if (options.use_login)
1.70 stevesk 1117: hostname = get_remote_name_or_ip(utmp_len,
1.120 markus 1118: options.verify_reverse_mapping);
1.1 markus 1119: /*
1120: * Close the connection descriptors; note that this is the child, and
1121: * the server will still have the socket open, and it is important
1122: * that we do not shutdown it. Note that the descriptors cannot be
1123: * closed before building the environment, as we call
1124: * get_remote_ipaddr there.
1125: */
1126: if (packet_get_connection_in() == packet_get_connection_out())
1127: close(packet_get_connection_in());
1128: else {
1129: close(packet_get_connection_in());
1130: close(packet_get_connection_out());
1131: }
1132: /*
1133: * Close all descriptors related to channels. They will still remain
1134: * open in the parent.
1135: */
1136: /* XXX better use close-on-exec? -markus */
1137: channel_close_all();
1138:
1139: /*
1140: * Close any extra file descriptors. Note that there may still be
1141: * descriptors left by system functions. They will be closed later.
1142: */
1143: endpwent();
1144:
1145: /*
1146: * Close any extra open file descriptors so that we don\'t have them
1147: * hanging around in clients. Note that we want to do this after
1148: * initgroups, because at least on Solaris 2.3 it leaves file
1149: * descriptors open.
1150: */
1151: for (i = 3; i < 64; i++)
1152: close(i);
1153:
1154: /*
1.125 deraadt 1155: * Must take new environment into use so that .ssh/rc,
1156: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1157: */
1158: environ = env;
1.102 markus 1159:
1160: #ifdef AFS
1161: /* Try to get AFS tokens for the local cell. */
1162: if (k_hasafs()) {
1163: char cell[64];
1.112 deraadt 1164:
1.102 markus 1165: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1166: krb_afslog(cell, 0);
1.112 deraadt 1167:
1.102 markus 1168: krb_afslog(0, 0);
1169: }
1170: #endif /* AFS */
1.104 markus 1171:
1172: /* Change current directory to the user\'s home directory. */
1173: if (chdir(pw->pw_dir) < 0) {
1174: fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1175: pw->pw_dir, strerror(errno));
1176: #ifdef HAVE_LOGIN_CAP
1177: if (login_getcapbool(lc, "requirehome", 0))
1178: exit(1);
1179: #endif
1180: }
1.1 markus 1181:
1.127 markus 1182: if (!options.use_login)
1183: do_rc_files(s, shell);
1.67 markus 1184:
1185: /* restore SIGPIPE for child */
1186: signal(SIGPIPE, SIG_DFL);
1187:
1.127 markus 1188: if (options.use_login) {
1.130 provos 1189: launch_login(pw, hostname);
1190: /* NEVERREACHED */
1.127 markus 1191: }
1192:
1193: /* Get the last component of the shell name. */
1194: if ((shell0 = strrchr(shell, '/')) != NULL)
1195: shell0++;
1196: else
1197: shell0 = shell;
1198:
1.1 markus 1199: /*
1200: * If we have no command, execute the shell. In this case, the shell
1201: * name to be passed in argv[0] is preceded by '-' to indicate that
1202: * this is a login shell.
1203: */
1204: if (!command) {
1.127 markus 1205: char argv0[256];
1.1 markus 1206:
1.127 markus 1207: /* Start the shell. Set initial character to '-'. */
1208: argv0[0] = '-';
1.1 markus 1209:
1.127 markus 1210: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1211: >= sizeof(argv0) - 1) {
1.127 markus 1212: errno = EINVAL;
1.1 markus 1213: perror(shell);
1214: exit(1);
1.127 markus 1215: }
1.1 markus 1216:
1.127 markus 1217: /* Execute the shell. */
1218: argv[0] = argv0;
1219: argv[1] = NULL;
1220: execve(shell, argv, env);
1221:
1222: /* Executing the shell failed. */
1223: perror(shell);
1224: exit(1);
1.1 markus 1225: }
1226: /*
1227: * Execute the command using the user's shell. This uses the -c
1228: * option to execute the command.
1229: */
1.127 markus 1230: argv[0] = (char *) shell0;
1.1 markus 1231: argv[1] = "-c";
1232: argv[2] = (char *) command;
1233: argv[3] = NULL;
1234: execve(shell, argv, env);
1235: perror(shell);
1236: exit(1);
1237: }
1238:
1239: Session *
1240: session_new(void)
1241: {
1242: int i;
1243: static int did_init = 0;
1244: if (!did_init) {
1245: debug("session_new: init");
1.112 deraadt 1246: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1247: sessions[i].used = 0;
1248: }
1249: did_init = 1;
1250: }
1.112 deraadt 1251: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1252: Session *s = &sessions[i];
1253: if (! s->used) {
1.68 djm 1254: memset(s, 0, sizeof(*s));
1.1 markus 1255: s->chanid = -1;
1256: s->ptyfd = -1;
1257: s->ttyfd = -1;
1258: s->used = 1;
1.85 markus 1259: s->self = i;
1.1 markus 1260: debug("session_new: session %d", i);
1261: return s;
1262: }
1263: }
1264: return NULL;
1265: }
1266:
1.94 itojun 1267: static void
1.1 markus 1268: session_dump(void)
1269: {
1270: int i;
1.112 deraadt 1271: for (i = 0; i < MAX_SESSIONS; i++) {
1.1 markus 1272: Session *s = &sessions[i];
1.137 mpech 1273: debug("dump: used %d session %d %p channel %d pid %ld",
1.1 markus 1274: s->used,
1275: s->self,
1276: s,
1277: s->chanid,
1.137 mpech 1278: (long)s->pid);
1.1 markus 1279: }
1280: }
1281:
1.2 markus 1282: int
1.97 markus 1283: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1284: {
1285: Session *s = session_new();
1286: debug("session_open: channel %d", chanid);
1287: if (s == NULL) {
1288: error("no more sessions");
1289: return 0;
1290: }
1.97 markus 1291: s->authctxt = authctxt;
1292: s->pw = authctxt->pw;
1.7 markus 1293: if (s->pw == NULL)
1.54 stevesk 1294: fatal("no user for session %d", s->self);
1.2 markus 1295: debug("session_open: session %d: link with channel %d", s->self, chanid);
1296: s->chanid = chanid;
1297: return 1;
1298: }
1299:
1.130 provos 1300: Session *
1301: session_by_tty(char *tty)
1302: {
1303: int i;
1304: for (i = 0; i < MAX_SESSIONS; i++) {
1305: Session *s = &sessions[i];
1306: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1307: debug("session_by_tty: session %d tty %s", i, tty);
1308: return s;
1309: }
1310: }
1311: debug("session_by_tty: unknown tty %.100s", tty);
1312: session_dump();
1313: return NULL;
1314: }
1315:
1.94 itojun 1316: static Session *
1.2 markus 1317: session_by_channel(int id)
1318: {
1319: int i;
1.112 deraadt 1320: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1321: Session *s = &sessions[i];
1322: if (s->used && s->chanid == id) {
1323: debug("session_by_channel: session %d channel %d", i, id);
1324: return s;
1325: }
1326: }
1327: debug("session_by_channel: unknown channel %d", id);
1328: session_dump();
1329: return NULL;
1330: }
1331:
1.94 itojun 1332: static Session *
1.2 markus 1333: session_by_pid(pid_t pid)
1334: {
1335: int i;
1.137 mpech 1336: debug("session_by_pid: pid %ld", (long)pid);
1.112 deraadt 1337: for (i = 0; i < MAX_SESSIONS; i++) {
1.2 markus 1338: Session *s = &sessions[i];
1339: if (s->used && s->pid == pid)
1340: return s;
1341: }
1.137 mpech 1342: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1343: session_dump();
1344: return NULL;
1345: }
1346:
1.94 itojun 1347: static int
1.2 markus 1348: session_window_change_req(Session *s)
1349: {
1350: s->col = packet_get_int();
1351: s->row = packet_get_int();
1352: s->xpixel = packet_get_int();
1353: s->ypixel = packet_get_int();
1.116 markus 1354: packet_check_eom();
1.2 markus 1355: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1356: return 1;
1357: }
1358:
1.94 itojun 1359: static int
1.2 markus 1360: session_pty_req(Session *s)
1361: {
1.45 markus 1362: u_int len;
1.72 stevesk 1363: int n_bytes;
1.132 markus 1364:
1.86 markus 1365: if (no_pty_flag) {
1366: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1367: return 0;
1.86 markus 1368: }
1369: if (s->ttyfd != -1) {
1370: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1371: return 0;
1.134 markus 1372: }
1373: /* Get the time and hostname when the user last logged in. */
1374: if (options.print_lastlog) {
1375: s->hostname[0] = '\0';
1376: s->last_login_time = get_last_login_time(s->pw->pw_uid,
1377: s->pw->pw_name, s->hostname, sizeof(s->hostname));
1.86 markus 1378: }
1379:
1.2 markus 1380: s->term = packet_get_string(&len);
1.86 markus 1381:
1382: if (compat20) {
1383: s->col = packet_get_int();
1384: s->row = packet_get_int();
1385: } else {
1386: s->row = packet_get_int();
1387: s->col = packet_get_int();
1388: }
1.2 markus 1389: s->xpixel = packet_get_int();
1390: s->ypixel = packet_get_int();
1391:
1392: if (strcmp(s->term, "") == 0) {
1393: xfree(s->term);
1394: s->term = NULL;
1395: }
1.86 markus 1396:
1.2 markus 1397: /* Allocate a pty and open it. */
1.86 markus 1398: debug("Allocating pty.");
1.130 provos 1399: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1.86 markus 1400: if (s->term)
1401: xfree(s->term);
1.2 markus 1402: s->term = NULL;
1403: s->ptyfd = -1;
1404: s->ttyfd = -1;
1405: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1406: return 0;
1.2 markus 1407: }
1408: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1409:
1410: /* for SSH1 the tty modes length is not given */
1411: if (!compat20)
1412: n_bytes = packet_remaining();
1413: tty_parse_modes(s->ttyfd, &n_bytes);
1414:
1.2 markus 1415: /*
1416: * Add a cleanup function to clear the utmp entry and record logout
1417: * time in case we call fatal() (e.g., the connection gets closed).
1418: */
1.85 markus 1419: fatal_add_cleanup(session_pty_cleanup, (void *)s);
1.130 provos 1420: if (!use_privsep)
1421: pty_setowner(s->pw, s->tty);
1.86 markus 1422:
1423: /* Set window size from the packet. */
1.2 markus 1424: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1425:
1.116 markus 1426: packet_check_eom();
1.9 markus 1427: session_proctitle(s);
1.2 markus 1428: return 1;
1429: }
1430:
1.94 itojun 1431: static int
1.7 markus 1432: session_subsystem_req(Session *s)
1433: {
1.105 markus 1434: struct stat st;
1.45 markus 1435: u_int len;
1.7 markus 1436: int success = 0;
1.105 markus 1437: char *cmd, *subsys = packet_get_string(&len);
1.18 jakob 1438: int i;
1.7 markus 1439:
1.116 markus 1440: packet_check_eom();
1.155 itojun 1441: logit("subsystem request for %.100s", subsys);
1.18 jakob 1442:
1443: for (i = 0; i < options.num_subsystems; i++) {
1.105 markus 1444: if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1445: cmd = options.subsystem_command[i];
1446: if (stat(cmd, &st) < 0) {
1447: error("subsystem: cannot stat %s: %s", cmd,
1448: strerror(errno));
1449: break;
1450: }
1451: debug("subsystem: exec() %s", cmd);
1.64 markus 1452: s->is_subsystem = 1;
1.105 markus 1453: do_exec(s, cmd);
1.18 jakob 1454: success = 1;
1.122 markus 1455: break;
1.18 jakob 1456: }
1457: }
1458:
1459: if (!success)
1.155 itojun 1460: logit("subsystem request for %.100s failed, subsystem not found",
1.105 markus 1461: subsys);
1.7 markus 1462:
1463: xfree(subsys);
1464: return success;
1465: }
1466:
1.94 itojun 1467: static int
1.7 markus 1468: session_x11_req(Session *s)
1469: {
1.81 markus 1470: int success;
1.7 markus 1471:
1472: s->single_connection = packet_get_char();
1473: s->auth_proto = packet_get_string(NULL);
1474: s->auth_data = packet_get_string(NULL);
1475: s->screen = packet_get_int();
1.116 markus 1476: packet_check_eom();
1.7 markus 1477:
1.81 markus 1478: success = session_setup_x11fwd(s);
1479: if (!success) {
1.7 markus 1480: xfree(s->auth_proto);
1481: xfree(s->auth_data);
1.84 markus 1482: s->auth_proto = NULL;
1483: s->auth_data = NULL;
1.7 markus 1484: }
1.81 markus 1485: return success;
1.7 markus 1486: }
1487:
1.94 itojun 1488: static int
1.19 markus 1489: session_shell_req(Session *s)
1490: {
1.116 markus 1491: packet_check_eom();
1.90 markus 1492: do_exec(s, NULL);
1.19 markus 1493: return 1;
1494: }
1495:
1.94 itojun 1496: static int
1.19 markus 1497: session_exec_req(Session *s)
1498: {
1.45 markus 1499: u_int len;
1.19 markus 1500: char *command = packet_get_string(&len);
1.116 markus 1501: packet_check_eom();
1.90 markus 1502: do_exec(s, command);
1.92 markus 1503: xfree(command);
1.19 markus 1504: return 1;
1505: }
1506:
1.94 itojun 1507: static int
1.157 ! markus 1508: session_break_req(Session *s)
! 1509: {
! 1510: u_int break_length;
! 1511:
! 1512: break_length = packet_get_int();
! 1513: packet_check_eom();
! 1514:
! 1515: if (s->ttyfd == -1)
! 1516: return 0;
! 1517: /* we will sleep from 500ms to 3000ms */
! 1518: break_length = MIN(break_length, 3000);
! 1519: break_length = MAX(break_length, 500);
! 1520: ioctl(s->ttyfd, TIOCSBRK, NULL);
! 1521: /* should we care about EINTR? */
! 1522: usleep(break_length * 1000);
! 1523: ioctl(s->ttyfd, TIOCCBRK, NULL);
! 1524: return 1;
! 1525: }
! 1526:
! 1527: static int
1.43 markus 1528: session_auth_agent_req(Session *s)
1529: {
1530: static int called = 0;
1.116 markus 1531: packet_check_eom();
1.44 markus 1532: if (no_agent_forwarding_flag) {
1533: debug("session_auth_agent_req: no_agent_forwarding_flag");
1534: return 0;
1535: }
1.43 markus 1536: if (called) {
1537: return 0;
1538: } else {
1539: called = 1;
1540: return auth_input_request_forwarding(s->pw);
1541: }
1542: }
1543:
1.123 markus 1544: int
1545: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1546: {
1547: int success = 0;
1548: Session *s;
1549:
1.123 markus 1550: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1551: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1552: c->self, rtype);
1553: return 0;
1554: }
1555: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1556:
1557: /*
1.64 markus 1558: * a session is in LARVAL state until a shell, a command
1559: * or a subsystem is executed
1.2 markus 1560: */
1561: if (c->type == SSH_CHANNEL_LARVAL) {
1562: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1563: success = session_shell_req(s);
1.2 markus 1564: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1565: success = session_exec_req(s);
1.2 markus 1566: } else if (strcmp(rtype, "pty-req") == 0) {
1.3 markus 1567: success = session_pty_req(s);
1.7 markus 1568: } else if (strcmp(rtype, "x11-req") == 0) {
1569: success = session_x11_req(s);
1.43 markus 1570: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1571: success = session_auth_agent_req(s);
1.7 markus 1572: } else if (strcmp(rtype, "subsystem") == 0) {
1573: success = session_subsystem_req(s);
1.157 ! markus 1574: } else if (strcmp(rtype, "break") == 0) {
! 1575: success = session_break_req(s);
1.2 markus 1576: }
1577: }
1578: if (strcmp(rtype, "window-change") == 0) {
1579: success = session_window_change_req(s);
1580: }
1.123 markus 1581: return success;
1.2 markus 1582: }
1583:
1584: void
1585: session_set_fds(Session *s, int fdin, int fdout, int fderr)
1586: {
1587: if (!compat20)
1588: fatal("session_set_fds: called for proto != 2.0");
1589: /*
1590: * now that have a child and a pipe to the child,
1591: * we can activate our channel and register the fd's
1592: */
1593: if (s->chanid == -1)
1594: fatal("no channel for session %d", s->self);
1595: channel_set_fds(s->chanid,
1596: fdout, fdin, fderr,
1.42 markus 1597: fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.126 markus 1598: 1,
1599: CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1600: }
1601:
1.85 markus 1602: /*
1603: * Function to perform pty cleanup. Also called if we get aborted abnormally
1604: * (e.g., due to a dropped connection).
1605: */
1.130 provos 1606: void
1607: session_pty_cleanup2(void *session)
1.1 markus 1608: {
1.85 markus 1609: Session *s = session;
1610:
1611: if (s == NULL) {
1612: error("session_pty_cleanup: no session");
1613: return;
1614: }
1615: if (s->ttyfd == -1)
1.1 markus 1616: return;
1617:
1.54 stevesk 1618: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1619:
1620: /* Record that the user has logged out. */
1.85 markus 1621: if (s->pid != 0)
1622: record_logout(s->pid, s->tty);
1.1 markus 1623:
1624: /* Release the pseudo-tty. */
1.130 provos 1625: if (getuid() == 0)
1626: pty_release(s->tty);
1.1 markus 1627:
1628: /*
1629: * Close the server side of the socket pairs. We must do this after
1630: * the pty cleanup, so that another process doesn't get this pty
1631: * while we're still cleaning up.
1632: */
1633: if (close(s->ptymaster) < 0)
1.130 provos 1634: error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1.108 markus 1635:
1636: /* unlink pty from session */
1637: s->ttyfd = -1;
1.2 markus 1638: }
1639:
1.130 provos 1640: void
1641: session_pty_cleanup(void *session)
1642: {
1643: PRIVSEP(session_pty_cleanup2(session));
1644: }
1645:
1.147 markus 1646: static char *
1647: sig2name(int sig)
1648: {
1649: #define SSH_SIG(x) if (sig == SIG ## x) return #x
1650: SSH_SIG(ABRT);
1651: SSH_SIG(ALRM);
1652: SSH_SIG(FPE);
1653: SSH_SIG(HUP);
1654: SSH_SIG(ILL);
1655: SSH_SIG(INT);
1656: SSH_SIG(KILL);
1657: SSH_SIG(PIPE);
1658: SSH_SIG(QUIT);
1659: SSH_SIG(SEGV);
1660: SSH_SIG(TERM);
1661: SSH_SIG(USR1);
1662: SSH_SIG(USR2);
1663: #undef SSH_SIG
1664: return "SIG@openssh.com";
1665: }
1666:
1.94 itojun 1667: static void
1.2 markus 1668: session_exit_message(Session *s, int status)
1669: {
1670: Channel *c;
1.124 markus 1671:
1672: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 1673: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 1674: s->self, s->chanid);
1.137 mpech 1675: debug("session_exit_message: session %d channel %d pid %ld",
1676: s->self, s->chanid, (long)s->pid);
1.2 markus 1677:
1678: if (WIFEXITED(status)) {
1.124 markus 1679: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 1680: packet_put_int(WEXITSTATUS(status));
1681: packet_send();
1682: } else if (WIFSIGNALED(status)) {
1.124 markus 1683: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 1684: packet_put_cstring(sig2name(WTERMSIG(status)));
1.2 markus 1685: packet_put_char(WCOREDUMP(status));
1686: packet_put_cstring("");
1687: packet_put_cstring("");
1688: packet_send();
1689: } else {
1690: /* Some weird exit cause. Just exit. */
1691: packet_disconnect("wait returned status %04x.", status);
1692: }
1693:
1694: /* disconnect channel */
1695: debug("session_exit_message: release channel %d", s->chanid);
1696: channel_cancel_cleanup(s->chanid);
1.5 markus 1697: /*
1698: * emulate a write failure with 'chan_write_failed', nobody will be
1699: * interested in data we write.
1700: * Note that we must not call 'chan_read_failed', since there could
1701: * be some more data waiting in the pipe.
1702: */
1.8 markus 1703: if (c->ostate != CHAN_OUTPUT_CLOSED)
1704: chan_write_failed(c);
1.2 markus 1705: s->chanid = -1;
1706: }
1707:
1.130 provos 1708: void
1.85 markus 1709: session_close(Session *s)
1.2 markus 1710: {
1.137 mpech 1711: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.85 markus 1712: if (s->ttyfd != -1) {
1713: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1714: session_pty_cleanup(s);
1715: }
1.2 markus 1716: if (s->term)
1717: xfree(s->term);
1718: if (s->display)
1719: xfree(s->display);
1.118 stevesk 1720: if (s->auth_display)
1721: xfree(s->auth_display);
1.2 markus 1722: if (s->auth_data)
1723: xfree(s->auth_data);
1724: if (s->auth_proto)
1725: xfree(s->auth_proto);
1726: s->used = 0;
1.9 markus 1727: session_proctitle(s);
1.2 markus 1728: }
1729:
1730: void
1731: session_close_by_pid(pid_t pid, int status)
1732: {
1733: Session *s = session_by_pid(pid);
1734: if (s == NULL) {
1.137 mpech 1735: debug("session_close_by_pid: no session for pid %ld",
1736: (long)pid);
1.2 markus 1737: return;
1738: }
1739: if (s->chanid != -1)
1740: session_exit_message(s, status);
1741: session_close(s);
1.98 markus 1742: }
1743:
1.2 markus 1744: /*
1745: * this is called when a channel dies before
1746: * the session 'child' itself dies
1747: */
1748: void
1749: session_close_by_channel(int id, void *arg)
1750: {
1751: Session *s = session_by_channel(id);
1752: if (s == NULL) {
1.107 markus 1753: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 1754: return;
1755: }
1.137 mpech 1756: debug("session_close_by_channel: channel %d child %ld",
1757: id, (long)s->pid);
1.107 markus 1758: if (s->pid != 0) {
1759: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 1760: /*
1761: * delay detach of session, but release pty, since
1762: * the fd's to the child are already closed
1763: */
1764: if (s->ttyfd != -1) {
1765: fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1766: session_pty_cleanup(s);
1767: }
1.107 markus 1768: return;
1769: }
1770: /* detach by removing callback */
1.2 markus 1771: channel_cancel_cleanup(s->chanid);
1772: s->chanid = -1;
1.106 markus 1773: session_close(s);
1774: }
1775:
1776: void
1.130 provos 1777: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 1778: {
1779: int i;
1.112 deraadt 1780: for (i = 0; i < MAX_SESSIONS; i++) {
1.106 markus 1781: Session *s = &sessions[i];
1.130 provos 1782: if (s->used) {
1783: if (closefunc != NULL)
1784: closefunc(s);
1785: else
1786: session_close(s);
1787: }
1.2 markus 1788: }
1.9 markus 1789: }
1790:
1.94 itojun 1791: static char *
1.9 markus 1792: session_tty_list(void)
1793: {
1794: static char buf[1024];
1795: int i;
1796: buf[0] = '\0';
1.112 deraadt 1797: for (i = 0; i < MAX_SESSIONS; i++) {
1.9 markus 1798: Session *s = &sessions[i];
1799: if (s->used && s->ttyfd != -1) {
1800: if (buf[0] != '\0')
1801: strlcat(buf, ",", sizeof buf);
1802: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1803: }
1804: }
1805: if (buf[0] == '\0')
1806: strlcpy(buf, "notty", sizeof buf);
1807: return buf;
1808: }
1809:
1810: void
1811: session_proctitle(Session *s)
1812: {
1813: if (s->pw == NULL)
1814: error("no user for session %d", s->self);
1815: else
1816: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 1817: }
1818:
1819: int
1820: session_setup_x11fwd(Session *s)
1821: {
1822: struct stat st;
1.109 stevesk 1823: char display[512], auth_display[512];
1824: char hostname[MAXHOSTNAMELEN];
1.81 markus 1825:
1826: if (no_x11_forwarding_flag) {
1827: packet_send_debug("X11 forwarding disabled in user configuration file.");
1828: return 0;
1829: }
1830: if (!options.x11_forwarding) {
1831: debug("X11 forwarding disabled in server configuration file.");
1832: return 0;
1833: }
1834: if (!options.xauth_location ||
1835: (stat(options.xauth_location, &st) == -1)) {
1836: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 1837: return 0;
1838: }
1839: if (options.use_login) {
1840: packet_send_debug("X11 forwarding disabled; "
1841: "not compatible with UseLogin=yes.");
1.81 markus 1842: return 0;
1843: }
1.87 markus 1844: if (s->display != NULL) {
1.81 markus 1845: debug("X11 display already set.");
1846: return 0;
1847: }
1.140 deraadt 1848: if (x11_create_display_inet(options.x11_display_offset,
1849: options.x11_use_localhost, s->single_connection,
1850: &s->display_number) == -1) {
1.87 markus 1851: debug("x11_create_display_inet failed.");
1.81 markus 1852: return 0;
1853: }
1.109 stevesk 1854:
1855: /* Set up a suitable value for the DISPLAY variable. */
1856: if (gethostname(hostname, sizeof(hostname)) < 0)
1857: fatal("gethostname: %.100s", strerror(errno));
1858: /*
1859: * auth_display must be used as the displayname when the
1860: * authorization entry is added with xauth(1). This will be
1861: * different than the DISPLAY string for localhost displays.
1862: */
1.119 stevesk 1863: if (options.x11_use_localhost) {
1.140 deraadt 1864: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 1865: s->display_number, s->screen);
1.140 deraadt 1866: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 1867: s->display_number, s->screen);
1.109 stevesk 1868: s->display = xstrdup(display);
1.118 stevesk 1869: s->auth_display = xstrdup(auth_display);
1.109 stevesk 1870: } else {
1.140 deraadt 1871: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 1872: s->display_number, s->screen);
1873: s->display = xstrdup(display);
1.118 stevesk 1874: s->auth_display = xstrdup(display);
1.109 stevesk 1875: }
1876:
1.81 markus 1877: return 1;
1.2 markus 1878: }
1879:
1.94 itojun 1880: static void
1.49 markus 1881: do_authenticated2(Authctxt *authctxt)
1.2 markus 1882: {
1.97 markus 1883: server_loop2(authctxt);
1.1 markus 1884: }
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