Annotation of src/usr.bin/ssh/session.c, Revision 1.78
1.1 markus 1: /*
2: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
3: * All rights reserved
1.37 deraadt 4: *
5: * As far as I am concerned, the code I have written for this software
6: * can be used freely for any purpose. Any derived versions of this
7: * software must be clearly marked as such, and if the derived work is
8: * incompatible with the protocol description in the RFC file, it must be
9: * called by a name other than "ssh" or "Secure Shell".
10: *
1.2 markus 11: * SSH2 support by Markus Friedl.
1.58 deraadt 12: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.37 deraadt 13: *
14: * Redistribution and use in source and binary forms, with or without
15: * modification, are permitted provided that the following conditions
16: * are met:
17: * 1. Redistributions of source code must retain the above copyright
18: * notice, this list of conditions and the following disclaimer.
19: * 2. Redistributions in binary form must reproduce the above copyright
20: * notice, this list of conditions and the following disclaimer in the
21: * documentation and/or other materials provided with the distribution.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.2 markus 33: */
1.1 markus 34:
35: #include "includes.h"
1.78 ! markus 36: RCSID("$OpenBSD: session.c,v 1.77 2001/05/30 12:55:13 markus Exp $");
1.1 markus 37:
1.51 markus 38: #include "ssh.h"
39: #include "ssh1.h"
40: #include "ssh2.h"
1.1 markus 41: #include "xmalloc.h"
1.59 djm 42: #include "sshpty.h"
1.1 markus 43: #include "packet.h"
44: #include "buffer.h"
45: #include "mpaux.h"
46: #include "uidswap.h"
47: #include "compat.h"
1.78 ! markus 48: #include "channels.h"
1.2 markus 49: #include "bufaux.h"
50: #include "auth.h"
1.19 markus 51: #include "auth-options.h"
1.50 markus 52: #include "pathnames.h"
1.51 markus 53: #include "log.h"
54: #include "servconf.h"
1.59 djm 55: #include "sshlogin.h"
1.51 markus 56: #include "serverloop.h"
57: #include "canohost.h"
1.55 itojun 58: #include "session.h"
1.2 markus 59:
1.1 markus 60: /* types */
61:
62: #define TTYSZ 64
63: typedef struct Session Session;
64: struct Session {
65: int used;
66: int self;
67: struct passwd *pw;
68: pid_t pid;
69: /* tty */
70: char *term;
71: int ptyfd, ttyfd, ptymaster;
72: int row, col, xpixel, ypixel;
73: char tty[TTYSZ];
74: /* X11 */
75: char *display;
76: int screen;
77: char *auth_proto;
78: char *auth_data;
1.7 markus 79: int single_connection;
1.1 markus 80: /* proto 2 */
81: int chanid;
1.64 markus 82: int is_subsystem;
1.1 markus 83: };
84:
85: /* func */
86:
87: Session *session_new(void);
88: void session_set_fds(Session *s, int fdin, int fdout, int fderr);
89: void session_pty_cleanup(Session *s);
1.9 markus 90: void session_proctitle(Session *s);
1.63 markus 91: void do_exec_pty(Session *s, const char *command);
92: void do_exec_no_pty(Session *s, const char *command);
1.41 markus 93: void do_login(Session *s, const char *command);
1.60 markus 94: void do_child(Session *s, const char *command);
1.73 djm 95: void do_motd(void);
96: int check_quietlogin(Session *s, const char *command);
1.1 markus 97:
1.65 markus 98: void do_authenticated1(Authctxt *authctxt);
99: void do_authenticated2(Authctxt *authctxt);
100:
1.1 markus 101: /* import */
102: extern ServerOptions options;
103: extern char *__progname;
104: extern int log_stderr;
105: extern int debug_flag;
1.45 markus 106: extern u_int utmp_len;
1.21 markus 107: extern int startup_pipe;
1.74 markus 108: extern void destroy_sensitive_data(void);
1.21 markus 109:
1.1 markus 110: /* Local Xauthority file. */
111: static char *xauthfile;
112:
1.34 markus 113: /* original command from peer. */
1.53 stevesk 114: char *original_command = NULL;
1.34 markus 115:
1.1 markus 116: /* data */
117: #define MAX_SESSIONS 10
118: Session sessions[MAX_SESSIONS];
119:
1.28 millert 120: #ifdef HAVE_LOGIN_CAP
121: static login_cap_t *lc;
122: #endif
123:
1.65 markus 124: void
125: do_authenticated(Authctxt *authctxt)
126: {
127: /*
128: * Cancel the alarm we set to limit the time taken for
129: * authentication.
130: */
131: alarm(0);
132: if (startup_pipe != -1) {
133: close(startup_pipe);
134: startup_pipe = -1;
135: }
136: #ifdef HAVE_LOGIN_CAP
137: if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
138: error("unable to get login class");
139: return;
140: }
1.74 markus 141: #ifdef BSD_AUTH
142: if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
143: packet_disconnect("Approval failure for %s",
144: authctxt->pw->pw_name);
145: }
146: #endif
1.65 markus 147: #endif
148: /* setup the channel layer */
149: if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
150: channel_permit_all_opens();
151:
152: if (compat20)
153: do_authenticated2(authctxt);
154: else
155: do_authenticated1(authctxt);
156: }
157:
1.1 markus 158: /*
159: * Remove local Xauthority file.
160: */
161: void
162: xauthfile_cleanup_proc(void *ignore)
163: {
164: debug("xauthfile_cleanup_proc called");
165:
166: if (xauthfile != NULL) {
167: char *p;
168: unlink(xauthfile);
169: p = strrchr(xauthfile, '/');
170: if (p != NULL) {
171: *p = '\0';
172: rmdir(xauthfile);
173: }
174: xfree(xauthfile);
175: xauthfile = NULL;
176: }
177: }
178:
179: /*
180: * Function to perform cleanup if we get aborted abnormally (e.g., due to a
181: * dropped connection).
182: */
1.4 markus 183: void
1.1 markus 184: pty_cleanup_proc(void *session)
185: {
186: Session *s=session;
187: if (s == NULL)
188: fatal("pty_cleanup_proc: no session");
189: debug("pty_cleanup_proc: %s", s->tty);
190:
191: if (s->pid != 0) {
192: /* Record that the user has logged out. */
193: record_logout(s->pid, s->tty);
194: }
195:
196: /* Release the pseudo-tty. */
197: pty_release(s->tty);
198: }
199:
200: /*
201: * Prepares for an interactive session. This is called after the user has
202: * been successfully authenticated. During this message exchange, pseudo
203: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
204: * are requested, etc.
205: */
1.4 markus 206: void
1.65 markus 207: do_authenticated1(Authctxt *authctxt)
1.1 markus 208: {
209: Session *s;
1.65 markus 210: char *command;
211: int success, type, fd, n_bytes, plen, screen_flag, have_pty = 0;
1.1 markus 212: int compression_level = 0, enable_compression_after_reply = 0;
1.45 markus 213: u_int proto_len, data_len, dlen;
1.76 djm 214: struct stat st;
1.1 markus 215:
1.61 markus 216: s = session_new();
1.65 markus 217: s->pw = authctxt->pw;
1.28 millert 218:
1.1 markus 219: /*
220: * We stay in this loop until the client requests to execute a shell
221: * or a command.
222: */
223: for (;;) {
1.65 markus 224: success = 0;
1.1 markus 225:
226: /* Get a packet from the client. */
227: type = packet_read(&plen);
228:
229: /* Process the packet. */
230: switch (type) {
231: case SSH_CMSG_REQUEST_COMPRESSION:
232: packet_integrity_check(plen, 4, type);
233: compression_level = packet_get_int();
234: if (compression_level < 1 || compression_level > 9) {
235: packet_send_debug("Received illegal compression level %d.",
236: compression_level);
237: break;
238: }
239: /* Enable compression after we have responded with SUCCESS. */
240: enable_compression_after_reply = 1;
241: success = 1;
242: break;
243:
244: case SSH_CMSG_REQUEST_PTY:
245: if (no_pty_flag) {
246: debug("Allocating a pty not permitted for this authentication.");
247: break;
248: }
249: if (have_pty)
250: packet_disconnect("Protocol error: you already have a pty.");
251:
252: debug("Allocating pty.");
253:
254: /* Allocate a pty and open it. */
255: if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
256: sizeof(s->tty))) {
257: error("Failed to allocate pty.");
258: break;
259: }
260: fatal_add_cleanup(pty_cleanup_proc, (void *)s);
1.65 markus 261: pty_setowner(s->pw, s->tty);
1.1 markus 262:
263: /* Get TERM from the packet. Note that the value may be of arbitrary length. */
264: s->term = packet_get_string(&dlen);
265: packet_integrity_check(dlen, strlen(s->term), type);
266: /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
267: /* Remaining bytes */
268: n_bytes = plen - (4 + dlen + 4 * 4);
269:
270: if (strcmp(s->term, "") == 0) {
271: xfree(s->term);
272: s->term = NULL;
273: }
274: /* Get window size from the packet. */
275: s->row = packet_get_int();
276: s->col = packet_get_int();
277: s->xpixel = packet_get_int();
278: s->ypixel = packet_get_int();
279: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
280:
281: /* Get tty modes from the packet. */
282: tty_parse_modes(s->ttyfd, &n_bytes);
283: packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
1.10 markus 284:
285: session_proctitle(s);
1.1 markus 286:
287: /* Indicate that we now have a pty. */
288: success = 1;
289: have_pty = 1;
290: break;
291:
292: case SSH_CMSG_X11_REQUEST_FORWARDING:
293: if (!options.x11_forwarding) {
294: packet_send_debug("X11 forwarding disabled in server configuration file.");
295: break;
296: }
1.76 djm 297: if (!options.xauth_location ||
298: (stat(options.xauth_location, &st) == -1)) {
1.16 markus 299: packet_send_debug("No xauth program; cannot forward with spoofing.");
300: break;
301: }
1.1 markus 302: if (no_x11_forwarding_flag) {
303: packet_send_debug("X11 forwarding not permitted for this authentication.");
304: break;
305: }
306: debug("Received request for X11 forwarding with auth spoofing.");
307: if (s->display != NULL)
308: packet_disconnect("Protocol error: X11 display already set.");
309:
310: s->auth_proto = packet_get_string(&proto_len);
311: s->auth_data = packet_get_string(&data_len);
312:
1.57 markus 313: screen_flag = packet_get_protocol_flags() &
314: SSH_PROTOFLAG_SCREEN_NUMBER;
315: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
316:
317: if (packet_remaining() == 4) {
318: if (!screen_flag)
319: debug2("Buggy client: "
320: "X11 screen flag missing");
1.56 markus 321: packet_integrity_check(plen,
322: 4 + proto_len + 4 + data_len + 4, type);
1.1 markus 323: s->screen = packet_get_int();
1.56 markus 324: } else {
325: packet_integrity_check(plen,
326: 4 + proto_len + 4 + data_len, type);
1.1 markus 327: s->screen = 0;
1.56 markus 328: }
1.1 markus 329: s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
330:
331: if (s->display == NULL)
332: break;
333:
334: /* Setup to always have a local .Xauthority. */
335: xauthfile = xmalloc(MAXPATHLEN);
336: strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
1.71 markus 337: temporarily_use_uid(s->pw);
1.1 markus 338: if (mkdtemp(xauthfile) == NULL) {
339: restore_uid();
340: error("private X11 dir: mkdtemp %s failed: %s",
341: xauthfile, strerror(errno));
342: xfree(xauthfile);
343: xauthfile = NULL;
1.7 markus 344: /* XXXX remove listening channels */
1.1 markus 345: break;
346: }
347: strlcat(xauthfile, "/cookies", MAXPATHLEN);
1.33 markus 348: fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
349: if (fd >= 0)
350: close(fd);
1.1 markus 351: restore_uid();
352: fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
353: success = 1;
354: break;
355:
356: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
357: if (no_agent_forwarding_flag || compat13) {
358: debug("Authentication agent forwarding not permitted for this authentication.");
359: break;
360: }
361: debug("Received authentication agent forwarding request.");
1.65 markus 362: success = auth_input_request_forwarding(s->pw);
1.1 markus 363: break;
364:
365: case SSH_CMSG_PORT_FORWARD_REQUEST:
366: if (no_port_forwarding_flag) {
367: debug("Port forwarding not permitted for this authentication.");
1.39 markus 368: break;
369: }
370: if (!options.allow_tcp_forwarding) {
371: debug("Port forwarding not permitted.");
1.1 markus 372: break;
373: }
374: debug("Received TCP/IP port forwarding request.");
1.65 markus 375: channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
1.1 markus 376: success = 1;
377: break;
378:
379: case SSH_CMSG_MAX_PACKET_SIZE:
380: if (packet_set_maxsize(packet_get_int()) > 0)
381: success = 1;
382: break;
383:
384: case SSH_CMSG_EXEC_SHELL:
385: case SSH_CMSG_EXEC_CMD:
386: if (type == SSH_CMSG_EXEC_CMD) {
387: command = packet_get_string(&dlen);
388: debug("Exec command '%.500s'", command);
389: packet_integrity_check(plen, 4 + dlen, type);
390: } else {
391: command = NULL;
392: packet_integrity_check(plen, 0, type);
393: }
394: if (forced_command != NULL) {
1.34 markus 395: original_command = command;
1.1 markus 396: command = forced_command;
397: debug("Forced command '%.500s'", forced_command);
398: }
399: if (have_pty)
1.63 markus 400: do_exec_pty(s, command);
1.1 markus 401: else
1.63 markus 402: do_exec_no_pty(s, command);
1.1 markus 403:
404: if (command != NULL)
405: xfree(command);
406: /* Cleanup user's local Xauthority file. */
407: if (xauthfile)
408: xauthfile_cleanup_proc(NULL);
409: return;
410:
411: default:
412: /*
413: * Any unknown messages in this phase are ignored,
414: * and a failure message is returned.
415: */
416: log("Unknown packet type received after authentication: %d", type);
417: }
418: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
419: packet_send();
420: packet_write_wait();
421:
422: /* Enable compression now that we have replied if appropriate. */
423: if (enable_compression_after_reply) {
424: enable_compression_after_reply = 0;
425: packet_start_compression(compression_level);
426: }
427: }
428: }
429:
430: /*
431: * This is called to fork and execute a command when we have no tty. This
432: * will call do_child from the child, and server_loop from the parent after
433: * setting up file descriptors and such.
434: */
1.4 markus 435: void
1.63 markus 436: do_exec_no_pty(Session *s, const char *command)
1.1 markus 437: {
438: int pid;
439:
440: #ifdef USE_PIPES
441: int pin[2], pout[2], perr[2];
442: /* Allocate pipes for communicating with the program. */
443: if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
444: packet_disconnect("Could not create pipes: %.100s",
445: strerror(errno));
446: #else /* USE_PIPES */
447: int inout[2], err[2];
448: /* Uses socket pairs to communicate with the program. */
449: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
450: socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
451: packet_disconnect("Could not create socket pairs: %.100s",
452: strerror(errno));
453: #endif /* USE_PIPES */
454: if (s == NULL)
455: fatal("do_exec_no_pty: no session");
456:
1.9 markus 457: session_proctitle(s);
1.1 markus 458:
459: /* Fork the child. */
460: if ((pid = fork()) == 0) {
461: /* Child. Reinitialize the log since the pid has changed. */
462: log_init(__progname, options.log_level, options.log_facility, log_stderr);
463:
464: /*
465: * Create a new session and process group since the 4.4BSD
466: * setlogin() affects the entire process group.
467: */
468: if (setsid() < 0)
469: error("setsid failed: %.100s", strerror(errno));
470:
471: #ifdef USE_PIPES
472: /*
473: * Redirect stdin. We close the parent side of the socket
474: * pair, and make the child side the standard input.
475: */
476: close(pin[1]);
477: if (dup2(pin[0], 0) < 0)
478: perror("dup2 stdin");
479: close(pin[0]);
480:
481: /* Redirect stdout. */
482: close(pout[0]);
483: if (dup2(pout[1], 1) < 0)
484: perror("dup2 stdout");
485: close(pout[1]);
486:
487: /* Redirect stderr. */
488: close(perr[0]);
489: if (dup2(perr[1], 2) < 0)
490: perror("dup2 stderr");
491: close(perr[1]);
492: #else /* USE_PIPES */
493: /*
494: * Redirect stdin, stdout, and stderr. Stdin and stdout will
495: * use the same socket, as some programs (particularly rdist)
496: * seem to depend on it.
497: */
498: close(inout[1]);
499: close(err[1]);
500: if (dup2(inout[0], 0) < 0) /* stdin */
501: perror("dup2 stdin");
502: if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
503: perror("dup2 stdout");
504: if (dup2(err[0], 2) < 0) /* stderr */
505: perror("dup2 stderr");
506: #endif /* USE_PIPES */
507:
508: /* Do processing for the child (exec command etc). */
1.60 markus 509: do_child(s, command);
1.1 markus 510: /* NOTREACHED */
511: }
512: if (pid < 0)
513: packet_disconnect("fork failed: %.100s", strerror(errno));
514: s->pid = pid;
1.47 markus 515: /* Set interactive/non-interactive mode. */
1.48 markus 516: packet_set_interactive(s->display != NULL);
1.1 markus 517: #ifdef USE_PIPES
518: /* We are the parent. Close the child sides of the pipes. */
519: close(pin[0]);
520: close(pout[1]);
521: close(perr[1]);
522:
1.2 markus 523: if (compat20) {
1.64 markus 524: session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
1.2 markus 525: } else {
526: /* Enter the interactive session. */
527: server_loop(pid, pin[1], pout[0], perr[0]);
1.64 markus 528: /* server_loop has closed pin[1], pout[0], and perr[0]. */
1.2 markus 529: }
1.1 markus 530: #else /* USE_PIPES */
531: /* We are the parent. Close the child sides of the socket pairs. */
532: close(inout[0]);
533: close(err[0]);
534:
535: /*
536: * Enter the interactive session. Note: server_loop must be able to
537: * handle the case that fdin and fdout are the same.
538: */
1.2 markus 539: if (compat20) {
1.64 markus 540: session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
1.2 markus 541: } else {
542: server_loop(pid, inout[1], inout[1], err[1]);
543: /* server_loop has closed inout[1] and err[1]. */
544: }
1.1 markus 545: #endif /* USE_PIPES */
546: }
547:
548: /*
549: * This is called to fork and execute a command when we have a tty. This
550: * will call do_child from the child, and server_loop from the parent after
551: * setting up file descriptors, controlling tty, updating wtmp, utmp,
552: * lastlog, and other such operations.
553: */
1.4 markus 554: void
1.63 markus 555: do_exec_pty(Session *s, const char *command)
1.1 markus 556: {
557: int fdout, ptyfd, ttyfd, ptymaster;
558: pid_t pid;
559:
560: if (s == NULL)
561: fatal("do_exec_pty: no session");
562: ptyfd = s->ptyfd;
563: ttyfd = s->ttyfd;
564:
565: /* Fork the child. */
566: if ((pid = fork()) == 0) {
1.24 markus 567: /* Child. Reinitialize the log because the pid has changed. */
1.1 markus 568: log_init(__progname, options.log_level, options.log_facility, log_stderr);
569:
570: /* Close the master side of the pseudo tty. */
571: close(ptyfd);
572:
573: /* Make the pseudo tty our controlling tty. */
574: pty_make_controlling_tty(&ttyfd, s->tty);
575:
576: /* Redirect stdin from the pseudo tty. */
577: if (dup2(ttyfd, fileno(stdin)) < 0)
578: error("dup2 stdin failed: %.100s", strerror(errno));
579:
580: /* Redirect stdout to the pseudo tty. */
581: if (dup2(ttyfd, fileno(stdout)) < 0)
582: error("dup2 stdin failed: %.100s", strerror(errno));
583:
584: /* Redirect stderr to the pseudo tty. */
585: if (dup2(ttyfd, fileno(stderr)) < 0)
586: error("dup2 stdin failed: %.100s", strerror(errno));
587:
588: /* Close the extra descriptor for the pseudo tty. */
589: close(ttyfd);
590:
1.24 markus 591: /* record login, etc. similar to login(1) */
1.41 markus 592: if (!(options.use_login && command == NULL))
593: do_login(s, command);
1.1 markus 594:
595: /* Do common processing for the child, such as execing the command. */
1.60 markus 596: do_child(s, command);
1.1 markus 597: /* NOTREACHED */
598: }
599: if (pid < 0)
600: packet_disconnect("fork failed: %.100s", strerror(errno));
601: s->pid = pid;
602:
603: /* Parent. Close the slave side of the pseudo tty. */
604: close(ttyfd);
605:
606: /*
607: * Create another descriptor of the pty master side for use as the
608: * standard input. We could use the original descriptor, but this
609: * simplifies code in server_loop. The descriptor is bidirectional.
610: */
611: fdout = dup(ptyfd);
612: if (fdout < 0)
613: packet_disconnect("dup #1 failed: %.100s", strerror(errno));
614:
615: /* we keep a reference to the pty master */
616: ptymaster = dup(ptyfd);
617: if (ptymaster < 0)
618: packet_disconnect("dup #2 failed: %.100s", strerror(errno));
619: s->ptymaster = ptymaster;
620:
621: /* Enter interactive session. */
1.47 markus 622: packet_set_interactive(1);
1.2 markus 623: if (compat20) {
624: session_set_fds(s, ptyfd, fdout, -1);
625: } else {
626: server_loop(pid, ptyfd, fdout, -1);
627: /* server_loop _has_ closed ptyfd and fdout. */
628: session_pty_cleanup(s);
1.24 markus 629: }
630: }
631:
632: /* administrative, login(1)-like work */
633: void
1.41 markus 634: do_login(Session *s, const char *command)
1.24 markus 635: {
636: char *time_string;
1.35 markus 637: char hostname[MAXHOSTNAMELEN];
1.24 markus 638: socklen_t fromlen;
639: struct sockaddr_storage from;
640: time_t last_login_time;
641: struct passwd * pw = s->pw;
642: pid_t pid = getpid();
643:
644: /*
645: * Get IP address of client. If the connection is not a socket, let
646: * the address be 0.0.0.0.
647: */
648: memset(&from, 0, sizeof(from));
649: if (packet_connection_is_on_socket()) {
650: fromlen = sizeof(from);
651: if (getpeername(packet_get_connection_in(),
652: (struct sockaddr *) & from, &fromlen) < 0) {
653: debug("getpeername: %.100s", strerror(errno));
654: fatal_cleanup();
655: }
656: }
1.25 markus 657:
1.35 markus 658: /* Get the time and hostname when the user last logged in. */
1.69 stevesk 659: if (options.print_lastlog) {
660: hostname[0] = '\0';
661: last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
662: hostname, sizeof(hostname));
663: }
1.35 markus 664:
1.24 markus 665: /* Record that there was a login on that tty from the remote host. */
666: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
1.70 stevesk 667: get_remote_name_or_ip(utmp_len, options.reverse_mapping_check),
668: (struct sockaddr *)&from);
1.24 markus 669:
1.73 djm 670: if (check_quietlogin(s, command))
1.24 markus 671: return;
1.73 djm 672:
1.69 stevesk 673: if (options.print_lastlog && last_login_time != 0) {
1.24 markus 674: time_string = ctime(&last_login_time);
675: if (strchr(time_string, '\n'))
676: *strchr(time_string, '\n') = 0;
1.40 markus 677: if (strcmp(hostname, "") == 0)
1.24 markus 678: printf("Last login: %s\r\n", time_string);
679: else
1.36 markus 680: printf("Last login: %s from %s\r\n", time_string, hostname);
1.24 markus 681: }
1.73 djm 682:
683: do_motd();
684: }
685:
686: /*
687: * Display the message of the day.
688: */
689: void
690: do_motd(void)
691: {
692: FILE *f;
693: char buf[256];
694:
1.24 markus 695: if (options.print_motd) {
1.28 millert 696: #ifdef HAVE_LOGIN_CAP
697: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
698: "/etc/motd"), "r");
699: #else
1.24 markus 700: f = fopen("/etc/motd", "r");
1.28 millert 701: #endif
1.24 markus 702: if (f) {
703: while (fgets(buf, sizeof(buf), f))
704: fputs(buf, stdout);
705: fclose(f);
706: }
1.2 markus 707: }
1.73 djm 708: }
709:
710:
711: /*
712: * Check for quiet login, either .hushlogin or command given.
713: */
714: int
715: check_quietlogin(Session *s, const char *command)
716: {
717: char buf[256];
718: struct passwd * pw = s->pw;
719: struct stat st;
720:
721: /* Return 1 if .hushlogin exists or a command given. */
722: if (command != NULL)
723: return 1;
724: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
725: #ifdef HAVE_LOGIN_CAP
726: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
727: return 1;
728: #else
729: if (stat(buf, &st) >= 0)
730: return 1;
731: #endif
732: return 0;
1.1 markus 733: }
734:
735: /*
736: * Sets the value of the given variable in the environment. If the variable
737: * already exists, its value is overriden.
738: */
1.4 markus 739: void
1.45 markus 740: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.1 markus 741: const char *value)
742: {
1.45 markus 743: u_int i, namelen;
1.1 markus 744: char **env;
745:
746: /*
747: * Find the slot where the value should be stored. If the variable
748: * already exists, we reuse the slot; otherwise we append a new slot
749: * at the end of the array, expanding if necessary.
750: */
751: env = *envp;
752: namelen = strlen(name);
753: for (i = 0; env[i]; i++)
754: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
755: break;
756: if (env[i]) {
757: /* Reuse the slot. */
758: xfree(env[i]);
759: } else {
760: /* New variable. Expand if necessary. */
761: if (i >= (*envsizep) - 1) {
762: (*envsizep) += 50;
763: env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
764: }
765: /* Need to set the NULL pointer at end of array beyond the new slot. */
766: env[i + 1] = NULL;
767: }
768:
769: /* Allocate space and format the variable in the appropriate slot. */
770: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
771: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
772: }
773:
774: /*
775: * Reads environment variables from the given file and adds/overrides them
776: * into the environment. If the file does not exist, this does nothing.
777: * Otherwise, it must consist of empty lines, comments (line starts with '#')
778: * and assignments of the form name=value. No other forms are allowed.
779: */
1.4 markus 780: void
1.45 markus 781: read_environment_file(char ***env, u_int *envsize,
1.1 markus 782: const char *filename)
783: {
784: FILE *f;
785: char buf[4096];
786: char *cp, *value;
787:
788: f = fopen(filename, "r");
789: if (!f)
790: return;
791:
792: while (fgets(buf, sizeof(buf), f)) {
793: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
794: ;
795: if (!*cp || *cp == '#' || *cp == '\n')
796: continue;
797: if (strchr(cp, '\n'))
798: *strchr(cp, '\n') = '\0';
799: value = strchr(cp, '=');
800: if (value == NULL) {
801: fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
802: continue;
803: }
1.14 deraadt 804: /*
805: * Replace the equals sign by nul, and advance value to
806: * the value string.
807: */
1.1 markus 808: *value = '\0';
809: value++;
810: child_set_env(env, envsize, cp, value);
811: }
812: fclose(f);
813: }
814:
815: /*
816: * Performs common processing for the child, such as setting up the
817: * environment, closing extra file descriptors, setting the user and group
818: * ids, and executing the command or shell.
819: */
1.4 markus 820: void
1.60 markus 821: do_child(Session *s, const char *command)
1.1 markus 822: {
1.32 markus 823: const char *shell, *hostname = NULL, *cp = NULL;
1.60 markus 824: struct passwd * pw = s->pw;
1.1 markus 825: char buf[256];
1.16 markus 826: char cmd[1024];
1.27 millert 827: FILE *f = NULL;
1.45 markus 828: u_int envsize, i;
1.1 markus 829: char **env;
830: extern char **environ;
831: struct stat st;
832: char *argv[10];
1.60 markus 833: int do_xauth = s->auth_proto != NULL && s->auth_data != NULL;
1.17 markus 834:
1.74 markus 835: /* remove hostkey from the child's memory */
836: destroy_sensitive_data();
837:
1.17 markus 838: /* login(1) is only called if we execute the login shell */
839: if (options.use_login && command != NULL)
840: options.use_login = 0;
1.1 markus 841:
1.27 millert 842: if (!options.use_login) {
1.28 millert 843: #ifdef HAVE_LOGIN_CAP
844: if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
845: f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
846: _PATH_NOLOGIN), "r");
847: #else
1.27 millert 848: if (pw->pw_uid)
849: f = fopen(_PATH_NOLOGIN, "r");
1.28 millert 850: #endif
1.27 millert 851: if (f) {
852: /* /etc/nologin exists. Print its contents and exit. */
853: while (fgets(buf, sizeof(buf), f))
854: fputs(buf, stderr);
855: fclose(f);
1.1 markus 856: exit(254);
1.27 millert 857: }
1.1 markus 858: }
1.28 millert 859: /* Set login name, uid, gid, and groups. */
1.1 markus 860: /* Login(1) does this as well, and it needs uid 0 for the "-h"
861: switch, so we let login(1) to this for us. */
862: if (!options.use_login) {
863: if (getuid() == 0 || geteuid() == 0) {
1.28 millert 864: #ifdef HAVE_LOGIN_CAP
865: if (setusercontext(lc, pw, pw->pw_uid,
866: (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
867: perror("unable to set user context");
868: exit(1);
869: }
870: #else
871: if (setlogin(pw->pw_name) < 0)
872: error("setlogin failed: %s", strerror(errno));
1.1 markus 873: if (setgid(pw->pw_gid) < 0) {
874: perror("setgid");
875: exit(1);
876: }
877: /* Initialize the group list. */
878: if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
879: perror("initgroups");
880: exit(1);
881: }
882: endgrent();
883:
884: /* Permanently switch to the desired uid. */
1.71 markus 885: permanently_set_uid(pw);
1.28 millert 886: #endif
1.1 markus 887: }
888: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1.31 deraadt 889: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1.1 markus 890: }
891: /*
892: * Get the shell from the password data. An empty shell field is
893: * legal, and means /bin/sh.
894: */
895: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.28 millert 896: #ifdef HAVE_LOGIN_CAP
897: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
898: #endif
1.1 markus 899:
900: #ifdef AFS
901: /* Try to get AFS tokens for the local cell. */
902: if (k_hasafs()) {
903: char cell[64];
904:
905: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
906: krb_afslog(cell, 0);
907:
908: krb_afslog(0, 0);
909: }
910: #endif /* AFS */
911:
912: /* Initialize the environment. */
913: envsize = 100;
914: env = xmalloc(envsize * sizeof(char *));
915: env[0] = NULL;
916:
917: if (!options.use_login) {
918: /* Set basic environment. */
919: child_set_env(&env, &envsize, "USER", pw->pw_name);
920: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
921: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.28 millert 922: #ifdef HAVE_LOGIN_CAP
1.29 millert 923: (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
924: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.28 millert 925: #else
1.29 millert 926: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1.28 millert 927: #endif
1.1 markus 928:
929: snprintf(buf, sizeof buf, "%.200s/%.50s",
930: _PATH_MAILDIR, pw->pw_name);
931: child_set_env(&env, &envsize, "MAIL", buf);
932:
933: /* Normal systems set SHELL by default. */
934: child_set_env(&env, &envsize, "SHELL", shell);
935: }
936: if (getenv("TZ"))
937: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
938:
939: /* Set custom environment options from RSA authentication. */
940: while (custom_environment) {
941: struct envstring *ce = custom_environment;
942: char *s = ce->s;
943: int i;
944: for (i = 0; s[i] != '=' && s[i]; i++);
945: if (s[i] == '=') {
946: s[i] = 0;
947: child_set_env(&env, &envsize, s, s + i + 1);
948: }
949: custom_environment = ce->next;
950: xfree(ce->s);
951: xfree(ce);
952: }
953:
954: snprintf(buf, sizeof buf, "%.50s %d %d",
955: get_remote_ipaddr(), get_remote_port(), get_local_port());
956: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
957:
1.60 markus 958: if (s->ttyfd != -1)
959: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
960: if (s->term)
961: child_set_env(&env, &envsize, "TERM", s->term);
962: if (s->display)
963: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 964: if (original_command)
965: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
966: original_command);
1.1 markus 967:
968: #ifdef KRB4
969: {
970: extern char *ticket;
971:
972: if (ticket)
973: child_set_env(&env, &envsize, "KRBTKFILE", ticket);
974: }
975: #endif /* KRB4 */
976:
977: if (xauthfile)
978: child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
979: if (auth_get_socket_name() != NULL)
980: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
981: auth_get_socket_name());
982:
983: /* read $HOME/.ssh/environment. */
984: if (!options.use_login) {
1.14 deraadt 985: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
986: pw->pw_dir);
1.1 markus 987: read_environment_file(&env, &envsize, buf);
988: }
989: if (debug_flag) {
990: /* dump the environment */
991: fprintf(stderr, "Environment:\n");
992: for (i = 0; env[i]; i++)
993: fprintf(stderr, " %.200s\n", env[i]);
994: }
1.26 millert 995: /* we have to stash the hostname before we close our socket. */
996: if (options.use_login)
1.70 stevesk 997: hostname = get_remote_name_or_ip(utmp_len,
998: options.reverse_mapping_check);
1.1 markus 999: /*
1000: * Close the connection descriptors; note that this is the child, and
1001: * the server will still have the socket open, and it is important
1002: * that we do not shutdown it. Note that the descriptors cannot be
1003: * closed before building the environment, as we call
1004: * get_remote_ipaddr there.
1005: */
1006: if (packet_get_connection_in() == packet_get_connection_out())
1007: close(packet_get_connection_in());
1008: else {
1009: close(packet_get_connection_in());
1010: close(packet_get_connection_out());
1011: }
1012: /*
1013: * Close all descriptors related to channels. They will still remain
1014: * open in the parent.
1015: */
1016: /* XXX better use close-on-exec? -markus */
1017: channel_close_all();
1018:
1019: /*
1020: * Close any extra file descriptors. Note that there may still be
1021: * descriptors left by system functions. They will be closed later.
1022: */
1023: endpwent();
1024:
1025: /*
1026: * Close any extra open file descriptors so that we don\'t have them
1027: * hanging around in clients. Note that we want to do this after
1028: * initgroups, because at least on Solaris 2.3 it leaves file
1029: * descriptors open.
1030: */
1031: for (i = 3; i < 64; i++)
1032: close(i);
1033:
1034: /* Change current directory to the user\'s home directory. */
1.28 millert 1035: if (chdir(pw->pw_dir) < 0) {
1.1 markus 1036: fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1037: pw->pw_dir, strerror(errno));
1.28 millert 1038: #ifdef HAVE_LOGIN_CAP
1039: if (login_getcapbool(lc, "requirehome", 0))
1040: exit(1);
1041: #endif
1042: }
1.1 markus 1043:
1044: /*
1045: * Must take new environment into use so that .ssh/rc, /etc/sshrc and
1046: * xauth are run in the proper environment.
1047: */
1048: environ = env;
1049:
1050: /*
1051: * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
1052: * in this order).
1053: */
1054: if (!options.use_login) {
1.74 markus 1055: /* ignore _PATH_SSH_USER_RC for subsystems */
1056: if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1.75 markus 1057: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1058: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1.1 markus 1059: if (debug_flag)
1.75 markus 1060: fprintf(stderr, "Running %s\n", cmd);
1061: f = popen(cmd, "w");
1.1 markus 1062: if (f) {
1.60 markus 1063: if (do_xauth)
1064: fprintf(f, "%s %s\n", s->auth_proto,
1065: s->auth_data);
1.1 markus 1066: pclose(f);
1067: } else
1.60 markus 1068: fprintf(stderr, "Could not run %s\n",
1069: _PATH_SSH_USER_RC);
1.50 markus 1070: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1.1 markus 1071: if (debug_flag)
1.60 markus 1072: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1073: _PATH_SSH_SYSTEM_RC);
1.50 markus 1074: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1.1 markus 1075: if (f) {
1.60 markus 1076: if (do_xauth)
1077: fprintf(f, "%s %s\n", s->auth_proto,
1078: s->auth_data);
1.1 markus 1079: pclose(f);
1080: } else
1.60 markus 1081: fprintf(stderr, "Could not run %s\n",
1082: _PATH_SSH_SYSTEM_RC);
1083: } else if (do_xauth && options.xauth_location != NULL) {
1.1 markus 1084: /* Add authority data to .Xauthority if appropriate. */
1.60 markus 1085: char *screen = strchr(s->display, ':');
1086:
1087: if (debug_flag) {
1088: fprintf(stderr,
1089: "Running %.100s add "
1090: "%.100s %.100s %.100s\n",
1091: options.xauth_location, s->display,
1092: s->auth_proto, s->auth_data);
1093: if (screen != NULL)
1.14 deraadt 1094: fprintf(stderr,
1.60 markus 1095: "Adding %.*s/unix%s %s %s\n",
1096: (int)(screen - s->display),
1097: s->display, screen,
1098: s->auth_proto, s->auth_data);
1099: }
1100: snprintf(cmd, sizeof cmd, "%s -q -",
1101: options.xauth_location);
1102: f = popen(cmd, "w");
1103: if (f) {
1104: fprintf(f, "add %s %s %s\n", s->display,
1105: s->auth_proto, s->auth_data);
1106: if (screen != NULL)
1107: fprintf(f, "add %.*s/unix%s %s %s\n",
1108: (int)(screen - s->display),
1109: s->display, screen,
1110: s->auth_proto,
1111: s->auth_data);
1112: pclose(f);
1113: } else {
1114: fprintf(stderr, "Could not run %s\n",
1115: cmd);
1.1 markus 1116: }
1117: }
1118: /* Get the last component of the shell name. */
1119: cp = strrchr(shell, '/');
1120: if (cp)
1121: cp++;
1122: else
1123: cp = shell;
1124: }
1.67 markus 1125:
1126: /* restore SIGPIPE for child */
1127: signal(SIGPIPE, SIG_DFL);
1128:
1.1 markus 1129: /*
1130: * If we have no command, execute the shell. In this case, the shell
1131: * name to be passed in argv[0] is preceded by '-' to indicate that
1132: * this is a login shell.
1133: */
1134: if (!command) {
1135: if (!options.use_login) {
1136: char buf[256];
1137:
1138: /*
1139: * Check for mail if we have a tty and it was enabled
1140: * in server options.
1141: */
1.60 markus 1142: if (s->ttyfd != -1 && options.check_mail) {
1.1 markus 1143: char *mailbox;
1144: struct stat mailstat;
1.60 markus 1145:
1.1 markus 1146: mailbox = getenv("MAIL");
1147: if (mailbox != NULL) {
1.14 deraadt 1148: if (stat(mailbox, &mailstat) != 0 ||
1149: mailstat.st_size == 0)
1.1 markus 1150: printf("No mail.\n");
1151: else if (mailstat.st_mtime < mailstat.st_atime)
1152: printf("You have mail.\n");
1153: else
1154: printf("You have new mail.\n");
1155: }
1156: }
1157: /* Start the shell. Set initial character to '-'. */
1158: buf[0] = '-';
1159: strncpy(buf + 1, cp, sizeof(buf) - 1);
1160: buf[sizeof(buf) - 1] = 0;
1161:
1162: /* Execute the shell. */
1163: argv[0] = buf;
1164: argv[1] = NULL;
1165: execve(shell, argv, env);
1166:
1167: /* Executing the shell failed. */
1168: perror(shell);
1169: exit(1);
1170:
1171: } else {
1172: /* Launch login(1). */
1173:
1.26 millert 1174: execl("/usr/bin/login", "login", "-h", hostname,
1.25 markus 1175: "-p", "-f", "--", pw->pw_name, NULL);
1.1 markus 1176:
1177: /* Login couldn't be executed, die. */
1178:
1179: perror("login");
1180: exit(1);
1181: }
1182: }
1183: /*
1184: * Execute the command using the user's shell. This uses the -c
1185: * option to execute the command.
1186: */
1187: argv[0] = (char *) cp;
1188: argv[1] = "-c";
1189: argv[2] = (char *) command;
1190: argv[3] = NULL;
1191: execve(shell, argv, env);
1192: perror(shell);
1193: exit(1);
1194: }
1195:
1196: Session *
1197: session_new(void)
1198: {
1199: int i;
1200: static int did_init = 0;
1201: if (!did_init) {
1202: debug("session_new: init");
1203: for(i = 0; i < MAX_SESSIONS; i++) {
1204: sessions[i].used = 0;
1205: sessions[i].self = i;
1206: }
1207: did_init = 1;
1208: }
1209: for(i = 0; i < MAX_SESSIONS; i++) {
1210: Session *s = &sessions[i];
1211: if (! s->used) {
1.68 djm 1212: memset(s, 0, sizeof(*s));
1.1 markus 1213: s->chanid = -1;
1214: s->ptyfd = -1;
1215: s->ttyfd = -1;
1216: s->used = 1;
1217: debug("session_new: session %d", i);
1218: return s;
1219: }
1220: }
1221: return NULL;
1222: }
1223:
1224: void
1225: session_dump(void)
1226: {
1227: int i;
1228: for(i = 0; i < MAX_SESSIONS; i++) {
1229: Session *s = &sessions[i];
1230: debug("dump: used %d session %d %p channel %d pid %d",
1231: s->used,
1232: s->self,
1233: s,
1234: s->chanid,
1235: s->pid);
1236: }
1237: }
1238:
1.2 markus 1239: int
1240: session_open(int chanid)
1241: {
1242: Session *s = session_new();
1243: debug("session_open: channel %d", chanid);
1244: if (s == NULL) {
1245: error("no more sessions");
1246: return 0;
1247: }
1.7 markus 1248: s->pw = auth_get_user();
1249: if (s->pw == NULL)
1.54 stevesk 1250: fatal("no user for session %d", s->self);
1.2 markus 1251: debug("session_open: session %d: link with channel %d", s->self, chanid);
1252: s->chanid = chanid;
1253: return 1;
1254: }
1255:
1256: Session *
1257: session_by_channel(int id)
1258: {
1259: int i;
1260: for(i = 0; i < MAX_SESSIONS; i++) {
1261: Session *s = &sessions[i];
1262: if (s->used && s->chanid == id) {
1263: debug("session_by_channel: session %d channel %d", i, id);
1264: return s;
1265: }
1266: }
1267: debug("session_by_channel: unknown channel %d", id);
1268: session_dump();
1269: return NULL;
1270: }
1271:
1272: Session *
1273: session_by_pid(pid_t pid)
1274: {
1275: int i;
1276: debug("session_by_pid: pid %d", pid);
1277: for(i = 0; i < MAX_SESSIONS; i++) {
1278: Session *s = &sessions[i];
1279: if (s->used && s->pid == pid)
1280: return s;
1281: }
1282: error("session_by_pid: unknown pid %d", pid);
1283: session_dump();
1284: return NULL;
1285: }
1286:
1287: int
1288: session_window_change_req(Session *s)
1289: {
1290: s->col = packet_get_int();
1291: s->row = packet_get_int();
1292: s->xpixel = packet_get_int();
1293: s->ypixel = packet_get_int();
1.3 markus 1294: packet_done();
1.2 markus 1295: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1296: return 1;
1297: }
1298:
1299: int
1300: session_pty_req(Session *s)
1301: {
1.45 markus 1302: u_int len;
1.72 stevesk 1303: int n_bytes;
1.2 markus 1304:
1.19 markus 1305: if (no_pty_flag)
1306: return 0;
1.2 markus 1307: if (s->ttyfd != -1)
1.3 markus 1308: return 0;
1.2 markus 1309: s->term = packet_get_string(&len);
1310: s->col = packet_get_int();
1311: s->row = packet_get_int();
1312: s->xpixel = packet_get_int();
1313: s->ypixel = packet_get_int();
1314:
1315: if (strcmp(s->term, "") == 0) {
1316: xfree(s->term);
1317: s->term = NULL;
1318: }
1319: /* Allocate a pty and open it. */
1320: if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1321: xfree(s->term);
1322: s->term = NULL;
1323: s->ptyfd = -1;
1324: s->ttyfd = -1;
1325: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1326: return 0;
1.2 markus 1327: }
1328: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1329: /*
1330: * Add a cleanup function to clear the utmp entry and record logout
1331: * time in case we call fatal() (e.g., the connection gets closed).
1332: */
1333: fatal_add_cleanup(pty_cleanup_proc, (void *)s);
1334: pty_setowner(s->pw, s->tty);
1335: /* Get window size from the packet. */
1336: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1337:
1.72 stevesk 1338: /* Get tty modes from the packet. */
1339: tty_parse_modes(s->ttyfd, &n_bytes);
1340: packet_done();
1341:
1.9 markus 1342: session_proctitle(s);
1343:
1.2 markus 1344: return 1;
1345: }
1346:
1.7 markus 1347: int
1348: session_subsystem_req(Session *s)
1349: {
1.45 markus 1350: u_int len;
1.7 markus 1351: int success = 0;
1352: char *subsys = packet_get_string(&len);
1.18 jakob 1353: int i;
1.7 markus 1354:
1355: packet_done();
1356: log("subsystem request for %s", subsys);
1.18 jakob 1357:
1358: for (i = 0; i < options.num_subsystems; i++) {
1359: if(strcmp(subsys, options.subsystem_name[i]) == 0) {
1360: debug("subsystem: exec() %s", options.subsystem_command[i]);
1.64 markus 1361: s->is_subsystem = 1;
1.63 markus 1362: do_exec_no_pty(s, options.subsystem_command[i]);
1.18 jakob 1363: success = 1;
1364: }
1365: }
1366:
1367: if (!success)
1368: log("subsystem request for %s failed, subsystem not found", subsys);
1.7 markus 1369:
1370: xfree(subsys);
1371: return success;
1372: }
1373:
1374: int
1375: session_x11_req(Session *s)
1376: {
1.33 markus 1377: int fd;
1.76 djm 1378: struct stat st;
1.22 deraadt 1379: if (no_x11_forwarding_flag) {
1.19 markus 1380: debug("X11 forwarding disabled in user configuration file.");
1381: return 0;
1382: }
1.7 markus 1383: if (!options.x11_forwarding) {
1384: debug("X11 forwarding disabled in server configuration file.");
1.76 djm 1385: return 0;
1386: }
1387: if (!options.xauth_location ||
1388: (stat(options.xauth_location, &st) == -1)) {
1389: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.7 markus 1390: return 0;
1391: }
1392: if (xauthfile != NULL) {
1393: debug("X11 fwd already started.");
1394: return 0;
1395: }
1396:
1397: debug("Received request for X11 forwarding with auth spoofing.");
1398: if (s->display != NULL)
1399: packet_disconnect("Protocol error: X11 display already set.");
1400:
1401: s->single_connection = packet_get_char();
1402: s->auth_proto = packet_get_string(NULL);
1403: s->auth_data = packet_get_string(NULL);
1404: s->screen = packet_get_int();
1405: packet_done();
1406:
1407: s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
1408: if (s->display == NULL) {
1409: xfree(s->auth_proto);
1410: xfree(s->auth_data);
1411: return 0;
1412: }
1413: xauthfile = xmalloc(MAXPATHLEN);
1414: strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
1.71 markus 1415: temporarily_use_uid(s->pw);
1.7 markus 1416: if (mkdtemp(xauthfile) == NULL) {
1417: restore_uid();
1418: error("private X11 dir: mkdtemp %s failed: %s",
1419: xauthfile, strerror(errno));
1420: xfree(xauthfile);
1421: xauthfile = NULL;
1422: xfree(s->auth_proto);
1423: xfree(s->auth_data);
1424: /* XXXX remove listening channels */
1425: return 0;
1426: }
1427: strlcat(xauthfile, "/cookies", MAXPATHLEN);
1.33 markus 1428: fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
1429: if (fd >= 0)
1430: close(fd);
1.7 markus 1431: restore_uid();
1432: fatal_add_cleanup(xauthfile_cleanup_proc, s);
1433: return 1;
1434: }
1435:
1.19 markus 1436: int
1437: session_shell_req(Session *s)
1438: {
1439: /* if forced_command == NULL, the shell is execed */
1440: char *shell = forced_command;
1441: packet_done();
1442: if (s->ttyfd == -1)
1.63 markus 1443: do_exec_no_pty(s, shell);
1.19 markus 1444: else
1.63 markus 1445: do_exec_pty(s, shell);
1.19 markus 1446: return 1;
1447: }
1448:
1449: int
1450: session_exec_req(Session *s)
1451: {
1.45 markus 1452: u_int len;
1.19 markus 1453: char *command = packet_get_string(&len);
1454: packet_done();
1455: if (forced_command) {
1.34 markus 1456: original_command = command;
1.19 markus 1457: command = forced_command;
1458: debug("Forced command '%.500s'", forced_command);
1459: }
1460: if (s->ttyfd == -1)
1.63 markus 1461: do_exec_no_pty(s, command);
1.19 markus 1462: else
1.63 markus 1463: do_exec_pty(s, command);
1.19 markus 1464: if (forced_command == NULL)
1465: xfree(command);
1466: return 1;
1467: }
1468:
1.43 markus 1469: int
1470: session_auth_agent_req(Session *s)
1471: {
1472: static int called = 0;
1473: packet_done();
1.44 markus 1474: if (no_agent_forwarding_flag) {
1475: debug("session_auth_agent_req: no_agent_forwarding_flag");
1476: return 0;
1477: }
1.43 markus 1478: if (called) {
1479: return 0;
1480: } else {
1481: called = 1;
1482: return auth_input_request_forwarding(s->pw);
1483: }
1484: }
1485:
1.2 markus 1486: void
1487: session_input_channel_req(int id, void *arg)
1488: {
1.45 markus 1489: u_int len;
1.2 markus 1490: int reply;
1491: int success = 0;
1492: char *rtype;
1493: Session *s;
1494: Channel *c;
1495:
1496: rtype = packet_get_string(&len);
1497: reply = packet_get_char();
1498:
1499: s = session_by_channel(id);
1500: if (s == NULL)
1501: fatal("session_input_channel_req: channel %d: no session", id);
1502: c = channel_lookup(id);
1503: if (c == NULL)
1504: fatal("session_input_channel_req: channel %d: bad channel", id);
1505:
1506: debug("session_input_channel_req: session %d channel %d request %s reply %d",
1507: s->self, id, rtype, reply);
1508:
1509: /*
1.64 markus 1510: * a session is in LARVAL state until a shell, a command
1511: * or a subsystem is executed
1.2 markus 1512: */
1513: if (c->type == SSH_CHANNEL_LARVAL) {
1514: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1515: success = session_shell_req(s);
1.2 markus 1516: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1517: success = session_exec_req(s);
1.2 markus 1518: } else if (strcmp(rtype, "pty-req") == 0) {
1.3 markus 1519: success = session_pty_req(s);
1.7 markus 1520: } else if (strcmp(rtype, "x11-req") == 0) {
1521: success = session_x11_req(s);
1.43 markus 1522: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1523: success = session_auth_agent_req(s);
1.7 markus 1524: } else if (strcmp(rtype, "subsystem") == 0) {
1525: success = session_subsystem_req(s);
1.2 markus 1526: }
1527: }
1528: if (strcmp(rtype, "window-change") == 0) {
1529: success = session_window_change_req(s);
1530: }
1531:
1532: if (reply) {
1533: packet_start(success ?
1534: SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1535: packet_put_int(c->remote_id);
1536: packet_send();
1537: }
1538: xfree(rtype);
1539: }
1540:
1541: void
1542: session_set_fds(Session *s, int fdin, int fdout, int fderr)
1543: {
1544: if (!compat20)
1545: fatal("session_set_fds: called for proto != 2.0");
1546: /*
1547: * now that have a child and a pipe to the child,
1548: * we can activate our channel and register the fd's
1549: */
1550: if (s->chanid == -1)
1551: fatal("no channel for session %d", s->self);
1552: channel_set_fds(s->chanid,
1553: fdout, fdin, fderr,
1.42 markus 1554: fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1555: 1);
1.2 markus 1556: }
1557:
1.1 markus 1558: void
1559: session_pty_cleanup(Session *s)
1560: {
1561: if (s == NULL || s->ttyfd == -1)
1562: return;
1563:
1.54 stevesk 1564: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1565:
1566: /* Cancel the cleanup function. */
1567: fatal_remove_cleanup(pty_cleanup_proc, (void *)s);
1568:
1569: /* Record that the user has logged out. */
1570: record_logout(s->pid, s->tty);
1571:
1572: /* Release the pseudo-tty. */
1573: pty_release(s->tty);
1574:
1575: /*
1576: * Close the server side of the socket pairs. We must do this after
1577: * the pty cleanup, so that another process doesn't get this pty
1578: * while we're still cleaning up.
1579: */
1580: if (close(s->ptymaster) < 0)
1581: error("close(s->ptymaster): %s", strerror(errno));
1.2 markus 1582: }
1583:
1584: void
1585: session_exit_message(Session *s, int status)
1586: {
1587: Channel *c;
1588: if (s == NULL)
1589: fatal("session_close: no session");
1590: c = channel_lookup(s->chanid);
1591: if (c == NULL)
1592: fatal("session_close: session %d: no channel %d",
1593: s->self, s->chanid);
1594: debug("session_exit_message: session %d channel %d pid %d",
1595: s->self, s->chanid, s->pid);
1596:
1597: if (WIFEXITED(status)) {
1598: channel_request_start(s->chanid,
1599: "exit-status", 0);
1600: packet_put_int(WEXITSTATUS(status));
1601: packet_send();
1602: } else if (WIFSIGNALED(status)) {
1603: channel_request_start(s->chanid,
1604: "exit-signal", 0);
1605: packet_put_int(WTERMSIG(status));
1606: packet_put_char(WCOREDUMP(status));
1607: packet_put_cstring("");
1608: packet_put_cstring("");
1609: packet_send();
1610: } else {
1611: /* Some weird exit cause. Just exit. */
1612: packet_disconnect("wait returned status %04x.", status);
1613: }
1614:
1615: /* disconnect channel */
1616: debug("session_exit_message: release channel %d", s->chanid);
1617: channel_cancel_cleanup(s->chanid);
1.5 markus 1618: /*
1619: * emulate a write failure with 'chan_write_failed', nobody will be
1620: * interested in data we write.
1621: * Note that we must not call 'chan_read_failed', since there could
1622: * be some more data waiting in the pipe.
1623: */
1.8 markus 1624: if (c->ostate != CHAN_OUTPUT_CLOSED)
1625: chan_write_failed(c);
1.2 markus 1626: s->chanid = -1;
1627: }
1628:
1629: void
1630: session_free(Session *s)
1631: {
1632: debug("session_free: session %d pid %d", s->self, s->pid);
1633: if (s->term)
1634: xfree(s->term);
1635: if (s->display)
1636: xfree(s->display);
1637: if (s->auth_data)
1638: xfree(s->auth_data);
1639: if (s->auth_proto)
1640: xfree(s->auth_proto);
1641: s->used = 0;
1642: }
1643:
1644: void
1645: session_close(Session *s)
1646: {
1647: session_pty_cleanup(s);
1648: session_free(s);
1.9 markus 1649: session_proctitle(s);
1.2 markus 1650: }
1651:
1652: void
1653: session_close_by_pid(pid_t pid, int status)
1654: {
1655: Session *s = session_by_pid(pid);
1656: if (s == NULL) {
1657: debug("session_close_by_pid: no session for pid %d", s->pid);
1658: return;
1659: }
1660: if (s->chanid != -1)
1661: session_exit_message(s, status);
1662: session_close(s);
1663: }
1664:
1665: /*
1666: * this is called when a channel dies before
1667: * the session 'child' itself dies
1668: */
1669: void
1670: session_close_by_channel(int id, void *arg)
1671: {
1672: Session *s = session_by_channel(id);
1673: if (s == NULL) {
1674: debug("session_close_by_channel: no session for channel %d", id);
1675: return;
1676: }
1677: /* disconnect channel */
1678: channel_cancel_cleanup(s->chanid);
1679: s->chanid = -1;
1680:
1681: debug("session_close_by_channel: channel %d kill %d", id, s->pid);
1682: if (s->pid == 0) {
1683: /* close session immediately */
1684: session_close(s);
1685: } else {
1686: /* notify child, delay session cleanup */
1687: if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0)
1688: error("session_close_by_channel: kill %d: %s",
1689: s->pid, strerror(errno));
1690: }
1.9 markus 1691: }
1692:
1693: char *
1694: session_tty_list(void)
1695: {
1696: static char buf[1024];
1697: int i;
1698: buf[0] = '\0';
1699: for(i = 0; i < MAX_SESSIONS; i++) {
1700: Session *s = &sessions[i];
1701: if (s->used && s->ttyfd != -1) {
1702: if (buf[0] != '\0')
1703: strlcat(buf, ",", sizeof buf);
1704: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1705: }
1706: }
1707: if (buf[0] == '\0')
1708: strlcpy(buf, "notty", sizeof buf);
1709: return buf;
1710: }
1711:
1712: void
1713: session_proctitle(Session *s)
1714: {
1715: if (s->pw == NULL)
1716: error("no user for session %d", s->self);
1717: else
1718: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.2 markus 1719: }
1720:
1721: void
1.49 markus 1722: do_authenticated2(Authctxt *authctxt)
1.2 markus 1723: {
1.65 markus 1724:
1.2 markus 1725: server_loop2();
1.7 markus 1726: if (xauthfile)
1727: xauthfile_cleanup_proc(NULL);
1.1 markus 1728: }
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