Annotation of src/usr.bin/ssh/session.c, Revision 1.257
1.257 ! djm 1: /* $OpenBSD: session.c,v 1.256 2010/06/25 07:20:04 djm Exp $ */
1.1 markus 2: /*
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.37 deraadt 5: *
6: * As far as I am concerned, the code I have written for this software
7: * can be used freely for any purpose. Any derived versions of this
8: * software must be clearly marked as such, and if the derived work is
9: * incompatible with the protocol description in the RFC file, it must be
10: * called by a name other than "ssh" or "Secure Shell".
11: *
1.2 markus 12: * SSH2 support by Markus Friedl.
1.95 markus 13: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.37 deraadt 14: *
15: * Redistribution and use in source and binary forms, with or without
16: * modification, are permitted provided that the following conditions
17: * are met:
18: * 1. Redistributions of source code must retain the above copyright
19: * notice, this list of conditions and the following disclaimer.
20: * 2. Redistributions in binary form must reproduce the above copyright
21: * notice, this list of conditions and the following disclaimer in the
22: * documentation and/or other materials provided with the distribution.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.2 markus 34: */
1.1 markus 35:
1.193 stevesk 36: #include <sys/types.h>
37: #include <sys/wait.h>
1.194 stevesk 38: #include <sys/un.h>
1.196 stevesk 39: #include <sys/stat.h>
1.207 stevesk 40: #include <sys/socket.h>
1.213 stevesk 41: #include <sys/param.h>
1.236 djm 42: #include <sys/queue.h>
1.192 stevesk 43:
1.209 stevesk 44: #include <errno.h>
1.253 djm 45: #include <fcntl.h>
1.204 stevesk 46: #include <grp.h>
1.223 djm 47: #include <login_cap.h>
1.192 stevesk 48: #include <paths.h>
1.206 stevesk 49: #include <pwd.h>
1.195 stevesk 50: #include <signal.h>
1.215 stevesk 51: #include <stdio.h>
1.214 stevesk 52: #include <stdlib.h>
1.212 stevesk 53: #include <string.h>
1.211 stevesk 54: #include <unistd.h>
1.1 markus 55:
1.216 deraadt 56: #include "xmalloc.h"
1.51 markus 57: #include "ssh.h"
58: #include "ssh1.h"
59: #include "ssh2.h"
1.59 djm 60: #include "sshpty.h"
1.1 markus 61: #include "packet.h"
62: #include "buffer.h"
1.173 djm 63: #include "match.h"
1.1 markus 64: #include "uidswap.h"
65: #include "compat.h"
1.78 markus 66: #include "channels.h"
1.216 deraadt 67: #include "key.h"
68: #include "cipher.h"
69: #include "kex.h"
70: #include "hostfile.h"
1.2 markus 71: #include "auth.h"
1.19 markus 72: #include "auth-options.h"
1.50 markus 73: #include "pathnames.h"
1.51 markus 74: #include "log.h"
75: #include "servconf.h"
1.59 djm 76: #include "sshlogin.h"
1.51 markus 77: #include "serverloop.h"
78: #include "canohost.h"
1.226 djm 79: #include "misc.h"
1.55 itojun 80: #include "session.h"
1.216 deraadt 81: #ifdef GSSAPI
82: #include "ssh-gss.h"
83: #endif
1.130 provos 84: #include "monitor_wrap.h"
1.225 markus 85: #include "sftp.h"
1.171 markus 86:
87: #ifdef KRB5
88: #include <kafs.h>
1.161 markus 89: #endif
90:
1.242 djm 91: #define IS_INTERNAL_SFTP(c) \
92: (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
93: (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
94: c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
95: c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
96:
1.1 markus 97: /* func */
98:
99: Session *session_new(void);
1.256 djm 100: void session_set_fds(Session *, int, int, int, int, int);
1.165 markus 101: void session_pty_cleanup(Session *);
1.94 itojun 102: void session_proctitle(Session *);
103: int session_setup_x11fwd(Session *);
1.237 djm 104: int do_exec_pty(Session *, const char *);
105: int do_exec_no_pty(Session *, const char *);
106: int do_exec(Session *, const char *);
1.94 itojun 107: void do_login(Session *, const char *);
108: void do_child(Session *, const char *);
1.73 djm 109: void do_motd(void);
1.94 itojun 110: int check_quietlogin(Session *, const char *);
1.1 markus 111:
1.94 itojun 112: static void do_authenticated1(Authctxt *);
113: static void do_authenticated2(Authctxt *);
114:
115: static int session_pty_req(Session *);
1.65 markus 116:
1.1 markus 117: /* import */
118: extern ServerOptions options;
119: extern char *__progname;
120: extern int log_stderr;
121: extern int debug_flag;
1.45 markus 122: extern u_int utmp_len;
1.21 markus 123: extern int startup_pipe;
1.74 markus 124: extern void destroy_sensitive_data(void);
1.179 dtucker 125: extern Buffer loginmsg;
1.21 markus 126:
1.34 markus 127: /* original command from peer. */
1.92 markus 128: const char *original_command = NULL;
1.34 markus 129:
1.1 markus 130: /* data */
1.237 djm 131: static int sessions_first_unused = -1;
132: static int sessions_nalloc = 0;
133: static Session *sessions = NULL;
1.1 markus 134:
1.248 djm 135: #define SUBSYSTEM_NONE 0
136: #define SUBSYSTEM_EXT 1
137: #define SUBSYSTEM_INT_SFTP 2
138: #define SUBSYSTEM_INT_SFTP_ERROR 3
1.225 markus 139:
1.129 provos 140: login_cap_t *lc;
1.28 millert 141:
1.165 markus 142: static int is_child = 0;
143:
1.136 markus 144: /* Name and directory of socket for authentication agent forwarding. */
145: static char *auth_sock_name = NULL;
146: static char *auth_sock_dir = NULL;
147:
148: /* removes the agent forwarding socket */
149:
150: static void
1.165 markus 151: auth_sock_cleanup_proc(struct passwd *pw)
1.136 markus 152: {
153: if (auth_sock_name != NULL) {
154: temporarily_use_uid(pw);
155: unlink(auth_sock_name);
156: rmdir(auth_sock_dir);
157: auth_sock_name = NULL;
158: restore_uid();
159: }
160: }
161:
162: static int
163: auth_input_request_forwarding(struct passwd * pw)
164: {
165: Channel *nc;
1.237 djm 166: int sock = -1;
1.136 markus 167: struct sockaddr_un sunaddr;
168:
169: if (auth_sock_name != NULL) {
170: error("authentication forwarding requested twice.");
171: return 0;
172: }
173:
174: /* Temporarily drop privileged uid for mkdir/bind. */
175: temporarily_use_uid(pw);
176:
177: /* Allocate a buffer for the socket name, and format the name. */
1.237 djm 178: auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
1.136 markus 179:
180: /* Create private directory for socket */
181: if (mkdtemp(auth_sock_dir) == NULL) {
182: packet_send_debug("Agent forwarding disabled: "
183: "mkdtemp() failed: %.100s", strerror(errno));
184: restore_uid();
185: xfree(auth_sock_dir);
186: auth_sock_dir = NULL;
1.237 djm 187: goto authsock_err;
1.136 markus 188: }
1.237 djm 189:
190: xasprintf(&auth_sock_name, "%s/agent.%ld",
191: auth_sock_dir, (long) getpid());
1.136 markus 192:
193: /* Create the socket. */
194: sock = socket(AF_UNIX, SOCK_STREAM, 0);
1.237 djm 195: if (sock < 0) {
196: error("socket: %.100s", strerror(errno));
197: restore_uid();
198: goto authsock_err;
199: }
1.136 markus 200:
201: /* Bind it to the name. */
202: memset(&sunaddr, 0, sizeof(sunaddr));
203: sunaddr.sun_family = AF_UNIX;
204: strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
205:
1.237 djm 206: if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
207: error("bind: %.100s", strerror(errno));
208: restore_uid();
209: goto authsock_err;
210: }
1.136 markus 211:
212: /* Restore the privileged uid. */
213: restore_uid();
214:
215: /* Start listening on the socket. */
1.237 djm 216: if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
217: error("listen: %.100s", strerror(errno));
218: goto authsock_err;
219: }
1.136 markus 220:
221: /* Allocate a channel for the authentication agent socket. */
222: nc = channel_new("auth socket",
223: SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
224: CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1.156 markus 225: 0, "auth socket", 1);
1.245 djm 226: nc->path = xstrdup(auth_sock_name);
1.136 markus 227: return 1;
1.237 djm 228:
229: authsock_err:
230: if (auth_sock_name != NULL)
231: xfree(auth_sock_name);
232: if (auth_sock_dir != NULL) {
233: rmdir(auth_sock_dir);
234: xfree(auth_sock_dir);
235: }
236: if (sock != -1)
237: close(sock);
238: auth_sock_name = NULL;
239: auth_sock_dir = NULL;
240: return 0;
1.136 markus 241: }
242:
1.179 dtucker 243: static void
244: display_loginmsg(void)
245: {
1.183 djm 246: if (buffer_len(&loginmsg) > 0) {
247: buffer_append(&loginmsg, "\0", 1);
248: printf("%s", (char *)buffer_ptr(&loginmsg));
249: buffer_clear(&loginmsg);
250: }
1.179 dtucker 251: }
1.136 markus 252:
1.65 markus 253: void
254: do_authenticated(Authctxt *authctxt)
255: {
1.153 markus 256: setproctitle("%s", authctxt->pw->pw_name);
257:
1.65 markus 258: /* setup the channel layer */
259: if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
260: channel_permit_all_opens();
1.252 dtucker 261:
262: auth_debug_send();
1.65 markus 263:
264: if (compat20)
265: do_authenticated2(authctxt);
266: else
267: do_authenticated1(authctxt);
1.79 markus 268:
1.165 markus 269: do_cleanup(authctxt);
1.65 markus 270: }
271:
1.1 markus 272: /*
273: * Prepares for an interactive session. This is called after the user has
274: * been successfully authenticated. During this message exchange, pseudo
275: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
276: * are requested, etc.
277: */
1.94 itojun 278: static void
1.65 markus 279: do_authenticated1(Authctxt *authctxt)
1.1 markus 280: {
281: Session *s;
1.65 markus 282: char *command;
1.117 markus 283: int success, type, screen_flag;
1.139 deraadt 284: int enable_compression_after_reply = 0;
285: u_int proto_len, data_len, dlen, compression_level = 0;
1.1 markus 286:
1.61 markus 287: s = session_new();
1.181 markus 288: if (s == NULL) {
289: error("no more sessions");
290: return;
291: }
1.96 dugsong 292: s->authctxt = authctxt;
1.65 markus 293: s->pw = authctxt->pw;
1.28 millert 294:
1.1 markus 295: /*
296: * We stay in this loop until the client requests to execute a shell
297: * or a command.
298: */
299: for (;;) {
1.65 markus 300: success = 0;
1.1 markus 301:
302: /* Get a packet from the client. */
1.117 markus 303: type = packet_read();
1.1 markus 304:
305: /* Process the packet. */
306: switch (type) {
307: case SSH_CMSG_REQUEST_COMPRESSION:
308: compression_level = packet_get_int();
1.116 markus 309: packet_check_eom();
1.1 markus 310: if (compression_level < 1 || compression_level > 9) {
1.180 markus 311: packet_send_debug("Received invalid compression level %d.",
1.112 deraadt 312: compression_level);
1.138 markus 313: break;
314: }
1.186 markus 315: if (options.compression == COMP_NONE) {
1.138 markus 316: debug2("compression disabled");
1.1 markus 317: break;
318: }
319: /* Enable compression after we have responded with SUCCESS. */
320: enable_compression_after_reply = 1;
321: success = 1;
322: break;
323:
324: case SSH_CMSG_REQUEST_PTY:
1.86 markus 325: success = session_pty_req(s);
1.1 markus 326: break;
327:
328: case SSH_CMSG_X11_REQUEST_FORWARDING:
329: s->auth_proto = packet_get_string(&proto_len);
330: s->auth_data = packet_get_string(&data_len);
331:
1.57 markus 332: screen_flag = packet_get_protocol_flags() &
333: SSH_PROTOFLAG_SCREEN_NUMBER;
334: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
335:
336: if (packet_remaining() == 4) {
337: if (!screen_flag)
338: debug2("Buggy client: "
339: "X11 screen flag missing");
1.1 markus 340: s->screen = packet_get_int();
1.56 markus 341: } else {
1.1 markus 342: s->screen = 0;
1.56 markus 343: }
1.116 markus 344: packet_check_eom();
1.81 markus 345: success = session_setup_x11fwd(s);
346: if (!success) {
347: xfree(s->auth_proto);
348: xfree(s->auth_data);
1.84 markus 349: s->auth_proto = NULL;
350: s->auth_data = NULL;
1.1 markus 351: }
352: break;
353:
354: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1.235 pyr 355: if (!options.allow_agent_forwarding ||
356: no_agent_forwarding_flag || compat13) {
1.1 markus 357: debug("Authentication agent forwarding not permitted for this authentication.");
358: break;
359: }
360: debug("Received authentication agent forwarding request.");
1.65 markus 361: success = auth_input_request_forwarding(s->pw);
1.1 markus 362: break;
363:
364: case SSH_CMSG_PORT_FORWARD_REQUEST:
365: if (no_port_forwarding_flag) {
366: debug("Port forwarding not permitted for this authentication.");
1.39 markus 367: break;
368: }
369: if (!options.allow_tcp_forwarding) {
370: debug("Port forwarding not permitted.");
1.1 markus 371: break;
372: }
373: debug("Received TCP/IP port forwarding request.");
1.208 markus 374: if (channel_input_port_forward_request(s->pw->pw_uid == 0,
375: options.gateway_ports) < 0) {
376: debug("Port forwarding failed.");
377: break;
378: }
1.1 markus 379: success = 1;
380: break;
381:
382: case SSH_CMSG_MAX_PACKET_SIZE:
383: if (packet_set_maxsize(packet_get_int()) > 0)
384: success = 1;
385: break;
386:
387: case SSH_CMSG_EXEC_SHELL:
388: case SSH_CMSG_EXEC_CMD:
389: if (type == SSH_CMSG_EXEC_CMD) {
390: command = packet_get_string(&dlen);
391: debug("Exec command '%.500s'", command);
1.237 djm 392: if (do_exec(s, command) != 0)
393: packet_disconnect(
394: "command execution failed");
1.92 markus 395: xfree(command);
1.1 markus 396: } else {
1.237 djm 397: if (do_exec(s, NULL) != 0)
398: packet_disconnect(
399: "shell execution failed");
1.1 markus 400: }
1.116 markus 401: packet_check_eom();
1.82 markus 402: session_close(s);
1.1 markus 403: return;
404:
405: default:
406: /*
407: * Any unknown messages in this phase are ignored,
408: * and a failure message is returned.
409: */
1.155 itojun 410: logit("Unknown packet type received after authentication: %d", type);
1.1 markus 411: }
412: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
413: packet_send();
414: packet_write_wait();
415:
416: /* Enable compression now that we have replied if appropriate. */
417: if (enable_compression_after_reply) {
418: enable_compression_after_reply = 0;
419: packet_start_compression(compression_level);
420: }
421: }
422: }
423:
1.238 markus 424: #define USE_PIPES
1.1 markus 425: /*
426: * This is called to fork and execute a command when we have no tty. This
427: * will call do_child from the child, and server_loop from the parent after
428: * setting up file descriptors and such.
429: */
1.237 djm 430: int
1.63 markus 431: do_exec_no_pty(Session *s, const char *command)
1.1 markus 432: {
1.137 mpech 433: pid_t pid;
1.238 markus 434: #ifdef USE_PIPES
435: int pin[2], pout[2], perr[2];
436:
1.253 djm 437: if (s == NULL)
438: fatal("do_exec_no_pty: no session");
439:
1.238 markus 440: /* Allocate pipes for communicating with the program. */
441: if (pipe(pin) < 0) {
442: error("%s: pipe in: %.100s", __func__, strerror(errno));
443: return -1;
444: }
445: if (pipe(pout) < 0) {
446: error("%s: pipe out: %.100s", __func__, strerror(errno));
447: close(pin[0]);
448: close(pin[1]);
449: return -1;
450: }
1.256 djm 451: if (pipe(perr) < 0) {
452: error("%s: pipe err: %.100s", __func__,
453: strerror(errno));
454: close(pin[0]);
455: close(pin[1]);
456: close(pout[0]);
457: close(pout[1]);
458: return -1;
1.238 markus 459: }
460: #else
1.237 djm 461: int inout[2], err[2];
1.1 markus 462:
1.253 djm 463: if (s == NULL)
464: fatal("do_exec_no_pty: no session");
465:
1.1 markus 466: /* Uses socket pairs to communicate with the program. */
1.237 djm 467: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
468: error("%s: socketpair #1: %.100s", __func__, strerror(errno));
469: return -1;
470: }
1.256 djm 471: if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
472: error("%s: socketpair #2: %.100s", __func__,
473: strerror(errno));
474: close(inout[0]);
475: close(inout[1]);
476: return -1;
1.237 djm 477: }
1.238 markus 478: #endif
1.237 djm 479:
1.9 markus 480: session_proctitle(s);
1.1 markus 481:
482: /* Fork the child. */
1.237 djm 483: switch ((pid = fork())) {
484: case -1:
485: error("%s: fork: %.100s", __func__, strerror(errno));
1.238 markus 486: #ifdef USE_PIPES
487: close(pin[0]);
488: close(pin[1]);
489: close(pout[0]);
490: close(pout[1]);
1.256 djm 491: close(perr[0]);
1.238 markus 492: close(perr[1]);
493: #else
1.237 djm 494: close(inout[0]);
495: close(inout[1]);
496: close(err[0]);
1.256 djm 497: close(err[1]);
1.238 markus 498: #endif
1.237 djm 499: return -1;
500: case 0:
1.165 markus 501: is_child = 1;
1.144 markus 502:
1.1 markus 503: /* Child. Reinitialize the log since the pid has changed. */
1.237 djm 504: log_init(__progname, options.log_level,
505: options.log_facility, log_stderr);
1.1 markus 506:
507: /*
508: * Create a new session and process group since the 4.4BSD
509: * setlogin() affects the entire process group.
510: */
511: if (setsid() < 0)
512: error("setsid failed: %.100s", strerror(errno));
513:
1.238 markus 514: #ifdef USE_PIPES
515: /*
516: * Redirect stdin. We close the parent side of the socket
517: * pair, and make the child side the standard input.
518: */
519: close(pin[1]);
520: if (dup2(pin[0], 0) < 0)
521: perror("dup2 stdin");
522: close(pin[0]);
523:
524: /* Redirect stdout. */
525: close(pout[0]);
526: if (dup2(pout[1], 1) < 0)
527: perror("dup2 stdout");
528: close(pout[1]);
529:
530: /* Redirect stderr. */
1.256 djm 531: close(perr[0]);
1.238 markus 532: if (dup2(perr[1], 2) < 0)
533: perror("dup2 stderr");
534: close(perr[1]);
535: #else
1.1 markus 536: /*
537: * Redirect stdin, stdout, and stderr. Stdin and stdout will
538: * use the same socket, as some programs (particularly rdist)
539: * seem to depend on it.
540: */
541: close(inout[1]);
1.256 djm 542: close(err[1]);
1.1 markus 543: if (dup2(inout[0], 0) < 0) /* stdin */
544: perror("dup2 stdin");
1.237 djm 545: if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
1.1 markus 546: perror("dup2 stdout");
1.238 markus 547: close(inout[0]);
1.1 markus 548: if (dup2(err[0], 2) < 0) /* stderr */
549: perror("dup2 stderr");
1.238 markus 550: close(err[0]);
551: #endif
1.1 markus 552:
553: /* Do processing for the child (exec command etc). */
1.60 markus 554: do_child(s, command);
1.1 markus 555: /* NOTREACHED */
1.237 djm 556: default:
557: break;
1.1 markus 558: }
1.237 djm 559:
1.1 markus 560: s->pid = pid;
1.47 markus 561: /* Set interactive/non-interactive mode. */
1.257 ! djm 562: packet_set_interactive(s->display != NULL,
! 563: options.ip_qos_interactive, options.ip_qos_bulk);
1.1 markus 564:
1.238 markus 565: #ifdef USE_PIPES
566: /* We are the parent. Close the child sides of the pipes. */
567: close(pin[0]);
568: close(pout[1]);
569: close(perr[1]);
570:
571: if (compat20) {
1.256 djm 572: session_set_fds(s, pin[1], pout[0], perr[0],
573: s->is_subsystem, 0);
1.238 markus 574: } else {
575: /* Enter the interactive session. */
576: server_loop(pid, pin[1], pout[0], perr[0]);
577: /* server_loop has closed pin[1], pout[0], and perr[0]. */
578: }
579: #else
1.1 markus 580: /* We are the parent. Close the child sides of the socket pairs. */
581: close(inout[0]);
582: close(err[0]);
583:
584: /*
585: * Enter the interactive session. Note: server_loop must be able to
586: * handle the case that fdin and fdout are the same.
587: */
1.2 markus 588: if (compat20) {
1.256 djm 589: session_set_fds(s, inout[1], inout[1], err[1],
590: s->is_subsystem, 0);
1.2 markus 591: } else {
592: server_loop(pid, inout[1], inout[1], err[1]);
593: /* server_loop has closed inout[1] and err[1]. */
594: }
1.238 markus 595: #endif
1.237 djm 596: return 0;
1.1 markus 597: }
598:
599: /*
600: * This is called to fork and execute a command when we have a tty. This
601: * will call do_child from the child, and server_loop from the parent after
602: * setting up file descriptors, controlling tty, updating wtmp, utmp,
603: * lastlog, and other such operations.
604: */
1.237 djm 605: int
1.63 markus 606: do_exec_pty(Session *s, const char *command)
1.1 markus 607: {
608: int fdout, ptyfd, ttyfd, ptymaster;
609: pid_t pid;
610:
611: if (s == NULL)
612: fatal("do_exec_pty: no session");
613: ptyfd = s->ptyfd;
614: ttyfd = s->ttyfd;
615:
1.237 djm 616: /*
617: * Create another descriptor of the pty master side for use as the
618: * standard input. We could use the original descriptor, but this
619: * simplifies code in server_loop. The descriptor is bidirectional.
620: * Do this before forking (and cleanup in the child) so as to
621: * detect and gracefully fail out-of-fd conditions.
622: */
623: if ((fdout = dup(ptyfd)) < 0) {
624: error("%s: dup #1: %s", __func__, strerror(errno));
625: close(ttyfd);
626: close(ptyfd);
627: return -1;
628: }
629: /* we keep a reference to the pty master */
630: if ((ptymaster = dup(ptyfd)) < 0) {
631: error("%s: dup #2: %s", __func__, strerror(errno));
632: close(ttyfd);
633: close(ptyfd);
634: close(fdout);
635: return -1;
636: }
637:
1.1 markus 638: /* Fork the child. */
1.237 djm 639: switch ((pid = fork())) {
640: case -1:
641: error("%s: fork: %.100s", __func__, strerror(errno));
642: close(fdout);
643: close(ptymaster);
644: close(ttyfd);
645: close(ptyfd);
646: return -1;
647: case 0:
1.165 markus 648: is_child = 1;
1.97 markus 649:
1.237 djm 650: close(fdout);
651: close(ptymaster);
652:
1.24 markus 653: /* Child. Reinitialize the log because the pid has changed. */
1.237 djm 654: log_init(__progname, options.log_level,
655: options.log_facility, log_stderr);
1.1 markus 656: /* Close the master side of the pseudo tty. */
657: close(ptyfd);
658:
659: /* Make the pseudo tty our controlling tty. */
660: pty_make_controlling_tty(&ttyfd, s->tty);
661:
1.103 markus 662: /* Redirect stdin/stdout/stderr from the pseudo tty. */
663: if (dup2(ttyfd, 0) < 0)
664: error("dup2 stdin: %s", strerror(errno));
665: if (dup2(ttyfd, 1) < 0)
666: error("dup2 stdout: %s", strerror(errno));
667: if (dup2(ttyfd, 2) < 0)
668: error("dup2 stderr: %s", strerror(errno));
1.1 markus 669:
670: /* Close the extra descriptor for the pseudo tty. */
671: close(ttyfd);
672:
1.24 markus 673: /* record login, etc. similar to login(1) */
1.41 markus 674: if (!(options.use_login && command == NULL))
675: do_login(s, command);
1.228 djm 676:
1.237 djm 677: /*
678: * Do common processing for the child, such as execing
679: * the command.
680: */
1.60 markus 681: do_child(s, command);
1.1 markus 682: /* NOTREACHED */
1.237 djm 683: default:
684: break;
1.1 markus 685: }
686: s->pid = pid;
687:
688: /* Parent. Close the slave side of the pseudo tty. */
689: close(ttyfd);
690:
1.237 djm 691: /* Enter interactive session. */
1.1 markus 692: s->ptymaster = ptymaster;
1.257 ! djm 693: packet_set_interactive(1,
! 694: options.ip_qos_interactive, options.ip_qos_bulk);
1.2 markus 695: if (compat20) {
1.256 djm 696: session_set_fds(s, ptyfd, fdout, -1, 1, 1);
1.2 markus 697: } else {
698: server_loop(pid, ptyfd, fdout, -1);
699: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 700: }
1.237 djm 701: return 0;
1.24 markus 702: }
703:
1.90 markus 704: /*
705: * This is called to fork and execute a command. If another command is
706: * to be forced, execute that instead.
707: */
1.237 djm 708: int
1.90 markus 709: do_exec(Session *s, const char *command)
710: {
1.237 djm 711: int ret;
712:
1.210 dtucker 713: if (options.adm_forced_command) {
714: original_command = command;
715: command = options.adm_forced_command;
1.248 djm 716: if (IS_INTERNAL_SFTP(command)) {
717: s->is_subsystem = s->is_subsystem ?
718: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
719: } else if (s->is_subsystem)
1.225 markus 720: s->is_subsystem = SUBSYSTEM_EXT;
1.210 dtucker 721: debug("Forced command (config) '%.900s'", command);
722: } else if (forced_command) {
1.90 markus 723: original_command = command;
724: command = forced_command;
1.248 djm 725: if (IS_INTERNAL_SFTP(command)) {
726: s->is_subsystem = s->is_subsystem ?
727: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
728: } else if (s->is_subsystem)
1.225 markus 729: s->is_subsystem = SUBSYSTEM_EXT;
1.210 dtucker 730: debug("Forced command (key option) '%.900s'", command);
1.90 markus 731: }
1.163 markus 732:
733: #ifdef GSSAPI
734: if (options.gss_authentication) {
735: temporarily_use_uid(s->pw);
736: ssh_gssapi_storecreds();
737: restore_uid();
738: }
739: #endif
1.90 markus 740: if (s->ttyfd != -1)
1.237 djm 741: ret = do_exec_pty(s, command);
1.90 markus 742: else
1.237 djm 743: ret = do_exec_no_pty(s, command);
1.90 markus 744:
1.92 markus 745: original_command = NULL;
1.179 dtucker 746:
747: /*
748: * Clear loginmsg: it's the child's responsibility to display
749: * it to the user, otherwise multiple sessions may accumulate
750: * multiple copies of the login messages.
751: */
752: buffer_clear(&loginmsg);
1.237 djm 753:
754: return ret;
1.90 markus 755: }
756:
757:
1.24 markus 758: /* administrative, login(1)-like work */
759: void
1.41 markus 760: do_login(Session *s, const char *command)
1.24 markus 761: {
762: socklen_t fromlen;
763: struct sockaddr_storage from;
764: struct passwd * pw = s->pw;
765: pid_t pid = getpid();
766:
767: /*
768: * Get IP address of client. If the connection is not a socket, let
769: * the address be 0.0.0.0.
770: */
771: memset(&from, 0, sizeof(from));
1.148 stevesk 772: fromlen = sizeof(from);
1.24 markus 773: if (packet_connection_is_on_socket()) {
774: if (getpeername(packet_get_connection_in(),
1.200 deraadt 775: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 776: debug("getpeername: %.100s", strerror(errno));
1.165 markus 777: cleanup_exit(255);
1.24 markus 778: }
779: }
1.25 markus 780:
1.24 markus 781: /* Record that there was a login on that tty from the remote host. */
1.133 markus 782: if (!use_privsep)
783: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
784: get_remote_name_or_ip(utmp_len,
1.158 markus 785: options.use_dns),
1.148 stevesk 786: (struct sockaddr *)&from, fromlen);
1.24 markus 787:
1.73 djm 788: if (check_quietlogin(s, command))
1.24 markus 789: return;
1.73 djm 790:
1.179 dtucker 791: display_loginmsg();
1.73 djm 792:
793: do_motd();
794: }
795:
796: /*
797: * Display the message of the day.
798: */
799: void
800: do_motd(void)
801: {
802: FILE *f;
803: char buf[256];
804:
1.24 markus 805: if (options.print_motd) {
1.28 millert 806: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
807: "/etc/motd"), "r");
1.24 markus 808: if (f) {
809: while (fgets(buf, sizeof(buf), f))
810: fputs(buf, stdout);
811: fclose(f);
812: }
1.2 markus 813: }
1.73 djm 814: }
815:
816:
817: /*
818: * Check for quiet login, either .hushlogin or command given.
819: */
820: int
821: check_quietlogin(Session *s, const char *command)
822: {
823: char buf[256];
1.96 dugsong 824: struct passwd *pw = s->pw;
1.73 djm 825: struct stat st;
826:
827: /* Return 1 if .hushlogin exists or a command given. */
828: if (command != NULL)
829: return 1;
830: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
831: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
832: return 1;
833: return 0;
1.1 markus 834: }
835:
836: /*
837: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 838: * already exists, its value is overridden.
1.1 markus 839: */
1.161 markus 840: void
1.45 markus 841: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 842: const char *value)
1.1 markus 843: {
1.164 markus 844: char **env;
845: u_int envsize;
1.45 markus 846: u_int i, namelen;
1.1 markus 847:
848: /*
849: * Find the slot where the value should be stored. If the variable
850: * already exists, we reuse the slot; otherwise we append a new slot
851: * at the end of the array, expanding if necessary.
852: */
853: env = *envp;
854: namelen = strlen(name);
855: for (i = 0; env[i]; i++)
856: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
857: break;
858: if (env[i]) {
859: /* Reuse the slot. */
860: xfree(env[i]);
861: } else {
862: /* New variable. Expand if necessary. */
1.164 markus 863: envsize = *envsizep;
864: if (i >= envsize - 1) {
865: if (envsize >= 1000)
866: fatal("child_set_env: too many env vars");
867: envsize += 50;
1.201 djm 868: env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1.164 markus 869: *envsizep = envsize;
1.1 markus 870: }
871: /* Need to set the NULL pointer at end of array beyond the new slot. */
872: env[i + 1] = NULL;
873: }
874:
875: /* Allocate space and format the variable in the appropriate slot. */
876: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
877: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
878: }
879:
880: /*
881: * Reads environment variables from the given file and adds/overrides them
882: * into the environment. If the file does not exist, this does nothing.
883: * Otherwise, it must consist of empty lines, comments (line starts with '#')
884: * and assignments of the form name=value. No other forms are allowed.
885: */
1.94 itojun 886: static void
1.45 markus 887: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 888: const char *filename)
1.1 markus 889: {
890: FILE *f;
891: char buf[4096];
892: char *cp, *value;
1.142 deraadt 893: u_int lineno = 0;
1.1 markus 894:
895: f = fopen(filename, "r");
896: if (!f)
897: return;
898:
899: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 900: if (++lineno > 1000)
901: fatal("Too many lines in environment file %s", filename);
1.1 markus 902: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
903: ;
904: if (!*cp || *cp == '#' || *cp == '\n')
905: continue;
1.224 gilles 906:
907: cp[strcspn(cp, "\n")] = '\0';
908:
1.1 markus 909: value = strchr(cp, '=');
910: if (value == NULL) {
1.142 deraadt 911: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
912: filename);
1.1 markus 913: continue;
914: }
1.14 deraadt 915: /*
916: * Replace the equals sign by nul, and advance value to
917: * the value string.
918: */
1.1 markus 919: *value = '\0';
920: value++;
921: child_set_env(env, envsize, cp, value);
922: }
923: fclose(f);
924: }
925:
1.127 markus 926: static char **
927: do_setup_env(Session *s, const char *shell)
1.1 markus 928: {
929: char buf[256];
1.127 markus 930: u_int i, envsize;
1.154 markus 931: char **env, *laddr;
1.127 markus 932: struct passwd *pw = s->pw;
1.1 markus 933:
934: /* Initialize the environment. */
935: envsize = 100;
1.220 djm 936: env = xcalloc(envsize, sizeof(char *));
1.1 markus 937: env[0] = NULL;
938:
1.161 markus 939: #ifdef GSSAPI
1.168 djm 940: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 941: * the childs environment as they see fit
942: */
943: ssh_gssapi_do_child(&env, &envsize);
944: #endif
945:
1.1 markus 946: if (!options.use_login) {
947: /* Set basic environment. */
1.173 djm 948: for (i = 0; i < s->num_env; i++)
1.178 deraadt 949: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 950: s->env[i].val);
951:
1.1 markus 952: child_set_env(&env, &envsize, "USER", pw->pw_name);
953: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
954: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 955: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
956: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
957: else
958: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 959:
960: snprintf(buf, sizeof buf, "%.200s/%.50s",
961: _PATH_MAILDIR, pw->pw_name);
962: child_set_env(&env, &envsize, "MAIL", buf);
963:
964: /* Normal systems set SHELL by default. */
965: child_set_env(&env, &envsize, "SHELL", shell);
966: }
967: if (getenv("TZ"))
968: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
969:
970: /* Set custom environment options from RSA authentication. */
1.110 markus 971: if (!options.use_login) {
972: while (custom_environment) {
973: struct envstring *ce = custom_environment;
1.143 deraadt 974: char *str = ce->s;
1.127 markus 975:
1.143 deraadt 976: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 977: ;
1.143 deraadt 978: if (str[i] == '=') {
979: str[i] = 0;
980: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 981: }
982: custom_environment = ce->next;
983: xfree(ce->s);
984: xfree(ce);
1.1 markus 985: }
986: }
987:
1.149 stevesk 988: /* SSH_CLIENT deprecated */
1.1 markus 989: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 990: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 991: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 992:
1.154 markus 993: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 994: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 995: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
996: xfree(laddr);
1.149 stevesk 997: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 998:
1.60 markus 999: if (s->ttyfd != -1)
1000: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1001: if (s->term)
1002: child_set_env(&env, &envsize, "TERM", s->term);
1003: if (s->display)
1004: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1005: if (original_command)
1006: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1007: original_command);
1.96 dugsong 1008: #ifdef KRB5
1009: if (s->authctxt->krb5_ticket_file)
1010: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1011: s->authctxt->krb5_ticket_file);
1.96 dugsong 1012: #endif
1.136 markus 1013: if (auth_sock_name != NULL)
1.1 markus 1014: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1015: auth_sock_name);
1.1 markus 1016:
1017: /* read $HOME/.ssh/environment. */
1.146 markus 1018: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1019: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1020: pw->pw_dir);
1.1 markus 1021: read_environment_file(&env, &envsize, buf);
1022: }
1023: if (debug_flag) {
1024: /* dump the environment */
1025: fprintf(stderr, "Environment:\n");
1026: for (i = 0; env[i]; i++)
1027: fprintf(stderr, " %.200s\n", env[i]);
1028: }
1.127 markus 1029: return env;
1030: }
1031:
1032: /*
1033: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1034: * first in this order).
1035: */
1036: static void
1037: do_rc_files(Session *s, const char *shell)
1038: {
1039: FILE *f = NULL;
1040: char cmd[1024];
1041: int do_xauth;
1042: struct stat st;
1043:
1044: do_xauth =
1045: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1046:
1.231 djm 1047: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1048: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.234 djm 1049: !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1050: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1051: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1052: if (debug_flag)
1053: fprintf(stderr, "Running %s\n", cmd);
1054: f = popen(cmd, "w");
1055: if (f) {
1056: if (do_xauth)
1057: fprintf(f, "%s %s\n", s->auth_proto,
1058: s->auth_data);
1059: pclose(f);
1060: } else
1061: fprintf(stderr, "Could not run %s\n",
1062: _PATH_SSH_USER_RC);
1063: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1064: if (debug_flag)
1065: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1066: _PATH_SSH_SYSTEM_RC);
1067: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1068: if (f) {
1069: if (do_xauth)
1070: fprintf(f, "%s %s\n", s->auth_proto,
1071: s->auth_data);
1072: pclose(f);
1073: } else
1074: fprintf(stderr, "Could not run %s\n",
1075: _PATH_SSH_SYSTEM_RC);
1076: } else if (do_xauth && options.xauth_location != NULL) {
1077: /* Add authority data to .Xauthority if appropriate. */
1078: if (debug_flag) {
1079: fprintf(stderr,
1.151 stevesk 1080: "Running %.500s remove %.100s\n",
1.165 markus 1081: options.xauth_location, s->auth_display);
1.151 stevesk 1082: fprintf(stderr,
1083: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1084: options.xauth_location, s->auth_display,
1085: s->auth_proto, s->auth_data);
1086: }
1087: snprintf(cmd, sizeof cmd, "%s -q -",
1088: options.xauth_location);
1089: f = popen(cmd, "w");
1090: if (f) {
1.151 stevesk 1091: fprintf(f, "remove %s\n",
1092: s->auth_display);
1.127 markus 1093: fprintf(f, "add %s %s %s\n",
1094: s->auth_display, s->auth_proto,
1095: s->auth_data);
1096: pclose(f);
1097: } else {
1098: fprintf(stderr, "Could not run %s\n",
1099: cmd);
1100: }
1101: }
1102: }
1103:
1104: static void
1105: do_nologin(struct passwd *pw)
1106: {
1107: FILE *f = NULL;
1.251 dtucker 1108: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1109: struct stat sb;
1.127 markus 1110:
1.251 dtucker 1111: if (login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1112: return;
1113: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1114:
1115: if (stat(nl, &sb) == -1) {
1116: if (nl != def_nl)
1117: xfree(nl);
1118: return;
1119: }
1120:
1121: /* /etc/nologin exists. Print its contents if we can and exit. */
1122: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1123: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1124: while (fgets(buf, sizeof(buf), f))
1125: fputs(buf, stderr);
1126: fclose(f);
1127: }
1.251 dtucker 1128: exit(254);
1.127 markus 1129: }
1130:
1.226 djm 1131: /*
1132: * Chroot into a directory after checking it for safety: all path components
1133: * must be root-owned directories with strict permissions.
1134: */
1135: static void
1136: safely_chroot(const char *path, uid_t uid)
1137: {
1138: const char *cp;
1139: char component[MAXPATHLEN];
1140: struct stat st;
1141:
1142: if (*path != '/')
1143: fatal("chroot path does not begin at root");
1144: if (strlen(path) >= sizeof(component))
1145: fatal("chroot path too long");
1146:
1147: /*
1148: * Descend the path, checking that each component is a
1149: * root-owned directory with strict permissions.
1150: */
1151: for (cp = path; cp != NULL;) {
1152: if ((cp = strchr(cp, '/')) == NULL)
1153: strlcpy(component, path, sizeof(component));
1154: else {
1155: cp++;
1156: memcpy(component, path, cp - path);
1157: component[cp - path] = '\0';
1158: }
1159:
1160: debug3("%s: checking '%s'", __func__, component);
1161:
1162: if (stat(component, &st) != 0)
1163: fatal("%s: stat(\"%s\"): %s", __func__,
1164: component, strerror(errno));
1165: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1166: fatal("bad ownership or modes for chroot "
1167: "directory %s\"%s\"",
1168: cp == NULL ? "" : "component ", component);
1169: if (!S_ISDIR(st.st_mode))
1170: fatal("chroot path %s\"%s\" is not a directory",
1171: cp == NULL ? "" : "component ", component);
1172:
1173: }
1174:
1175: if (chdir(path) == -1)
1176: fatal("Unable to chdir to chroot path \"%s\": "
1177: "%s", path, strerror(errno));
1178: if (chroot(path) == -1)
1179: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1180: if (chdir("/") == -1)
1181: fatal("%s: chdir(/) after chroot: %s",
1182: __func__, strerror(errno));
1183: verbose("Changed root directory to \"%s\"", path);
1184: }
1185:
1.127 markus 1186: /* Set login name, uid, gid, and groups. */
1.130 provos 1187: void
1.127 markus 1188: do_setusercontext(struct passwd *pw)
1189: {
1.227 djm 1190: char *chroot_path, *tmp;
1191:
1.127 markus 1192: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1193: /* Prepare groups */
1.127 markus 1194: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1195: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1196: perror("unable to set user context");
1197: exit(1);
1198: }
1.226 djm 1199:
1200: if (options.chroot_directory != NULL &&
1201: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1202: tmp = tilde_expand_filename(options.chroot_directory,
1203: pw->pw_uid);
1204: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1205: "u", pw->pw_name, (char *)NULL);
1.226 djm 1206: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1207: free(tmp);
1.226 djm 1208: free(chroot_path);
1209: }
1210:
1211: /* Set UID */
1212: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1213: perror("unable to set user context (setuser)");
1214: exit(1);
1215: }
1.127 markus 1216: }
1217: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1218: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1219: }
1220:
1.131 markus 1221: static void
1.172 markus 1222: do_pwchange(Session *s)
1223: {
1.179 dtucker 1224: fflush(NULL);
1.172 markus 1225: fprintf(stderr, "WARNING: Your password has expired.\n");
1226: if (s->ttyfd != -1) {
1.178 deraadt 1227: fprintf(stderr,
1.172 markus 1228: "You must change your password now and login again!\n");
1229: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1230: perror("passwd");
1231: } else {
1232: fprintf(stderr,
1233: "Password change required but no TTY available.\n");
1234: }
1235: exit(1);
1236: }
1237:
1238: static void
1.130 provos 1239: launch_login(struct passwd *pw, const char *hostname)
1240: {
1241: /* Launch login(1). */
1242:
1243: execl("/usr/bin/login", "login", "-h", hostname,
1244: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1245:
1246: /* Login couldn't be executed, die. */
1247:
1248: perror("login");
1249: exit(1);
1250: }
1251:
1.172 markus 1252: static void
1253: child_close_fds(void)
1254: {
1255: int i;
1256:
1257: if (packet_get_connection_in() == packet_get_connection_out())
1258: close(packet_get_connection_in());
1259: else {
1260: close(packet_get_connection_in());
1261: close(packet_get_connection_out());
1262: }
1263: /*
1264: * Close all descriptors related to channels. They will still remain
1265: * open in the parent.
1266: */
1267: /* XXX better use close-on-exec? -markus */
1268: channel_close_all();
1269:
1270: /*
1271: * Close any extra file descriptors. Note that there may still be
1272: * descriptors left by system functions. They will be closed later.
1273: */
1274: endpwent();
1275:
1276: /*
1.188 djm 1277: * Close any extra open file descriptors so that we don't have them
1.172 markus 1278: * hanging around in clients. Note that we want to do this after
1279: * initgroups, because at least on Solaris 2.3 it leaves file
1280: * descriptors open.
1281: */
1282: for (i = 3; i < 64; i++)
1283: close(i);
1284: }
1285:
1.127 markus 1286: /*
1287: * Performs common processing for the child, such as setting up the
1288: * environment, closing extra file descriptors, setting the user and group
1289: * ids, and executing the command or shell.
1290: */
1.225 markus 1291: #define ARGV_MAX 10
1.127 markus 1292: void
1293: do_child(Session *s, const char *command)
1294: {
1295: extern char **environ;
1296: char **env;
1.225 markus 1297: char *argv[ARGV_MAX];
1.127 markus 1298: const char *shell, *shell0, *hostname = NULL;
1299: struct passwd *pw = s->pw;
1.239 djm 1300: int r = 0;
1.127 markus 1301:
1302: /* remove hostkey from the child's memory */
1303: destroy_sensitive_data();
1304:
1.172 markus 1305: /* Force a password change */
1306: if (s->authctxt->force_pwchange) {
1307: do_setusercontext(pw);
1308: child_close_fds();
1309: do_pwchange(s);
1310: exit(1);
1311: }
1312:
1.127 markus 1313: /* login(1) is only called if we execute the login shell */
1314: if (options.use_login && command != NULL)
1315: options.use_login = 0;
1316:
1317: /*
1318: * Login(1) does this as well, and it needs uid 0 for the "-h"
1319: * switch, so we let login(1) to this for us.
1320: */
1321: if (!options.use_login) {
1322: do_nologin(pw);
1323: do_setusercontext(pw);
1324: }
1325:
1326: /*
1327: * Get the shell from the password data. An empty shell field is
1328: * legal, and means /bin/sh.
1329: */
1330: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1331:
1332: /*
1333: * Make sure $SHELL points to the shell from the password file,
1334: * even if shell is overridden from login.conf
1335: */
1336: env = do_setup_env(s, shell);
1337:
1.127 markus 1338: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1339:
1.26 millert 1340: /* we have to stash the hostname before we close our socket. */
1341: if (options.use_login)
1.70 stevesk 1342: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1343: options.use_dns);
1.1 markus 1344: /*
1345: * Close the connection descriptors; note that this is the child, and
1346: * the server will still have the socket open, and it is important
1347: * that we do not shutdown it. Note that the descriptors cannot be
1348: * closed before building the environment, as we call
1349: * get_remote_ipaddr there.
1350: */
1.172 markus 1351: child_close_fds();
1.1 markus 1352:
1353: /*
1.125 deraadt 1354: * Must take new environment into use so that .ssh/rc,
1355: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1356: */
1357: environ = env;
1.170 jakob 1358:
1359: #ifdef KRB5
1360: /*
1361: * At this point, we check to see if AFS is active and if we have
1362: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1363: * if we can (and need to) extend the ticket into an AFS token. If
1364: * we don't do this, we run into potential problems if the user's
1365: * home directory is in AFS and it's not world-readable.
1366: */
1367:
1368: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1369: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1370: char cell[64];
1371:
1372: debug("Getting AFS token");
1373:
1374: k_setpag();
1375:
1376: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1377: krb5_afslog(s->authctxt->krb5_ctx,
1378: s->authctxt->krb5_fwd_ccache, cell, NULL);
1379:
1380: krb5_afslog_home(s->authctxt->krb5_ctx,
1381: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1382: }
1383: #endif
1.104 markus 1384:
1.188 djm 1385: /* Change current directory to the user's home directory. */
1.104 markus 1386: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1387: /* Suppress missing homedir warning for chroot case */
1388: r = login_getcapbool(lc, "requirehome", 0);
1.254 djm 1389: if (r || options.chroot_directory == NULL ||
1390: strcasecmp(options.chroot_directory, "none") == 0)
1.239 djm 1391: fprintf(stderr, "Could not chdir to home "
1392: "directory %s: %s\n", pw->pw_dir,
1393: strerror(errno));
1394: if (r)
1.104 markus 1395: exit(1);
1396: }
1.230 djm 1397:
1398: closefrom(STDERR_FILENO + 1);
1.1 markus 1399:
1.127 markus 1400: if (!options.use_login)
1401: do_rc_files(s, shell);
1.67 markus 1402:
1403: /* restore SIGPIPE for child */
1.217 stevesk 1404: signal(SIGPIPE, SIG_DFL);
1.67 markus 1405:
1.248 djm 1406: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1407: printf("This service allows sftp connections only.\n");
1408: fflush(NULL);
1409: exit(1);
1410: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1411: extern int optind, optreset;
1412: int i;
1413: char *p, *args;
1414:
1.246 stevesk 1415: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1416: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1417: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1418: if (i < ARGV_MAX - 1)
1419: argv[i++] = p;
1420: argv[i] = NULL;
1421: optind = optreset = 1;
1422: __progname = argv[0];
1.226 djm 1423: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1424: }
1.247 djm 1425:
1426: fflush(NULL);
1.225 markus 1427:
1.127 markus 1428: if (options.use_login) {
1.130 provos 1429: launch_login(pw, hostname);
1430: /* NEVERREACHED */
1.127 markus 1431: }
1432:
1433: /* Get the last component of the shell name. */
1434: if ((shell0 = strrchr(shell, '/')) != NULL)
1435: shell0++;
1436: else
1437: shell0 = shell;
1438:
1.1 markus 1439: /*
1440: * If we have no command, execute the shell. In this case, the shell
1441: * name to be passed in argv[0] is preceded by '-' to indicate that
1442: * this is a login shell.
1443: */
1444: if (!command) {
1.127 markus 1445: char argv0[256];
1.1 markus 1446:
1.127 markus 1447: /* Start the shell. Set initial character to '-'. */
1448: argv0[0] = '-';
1.1 markus 1449:
1.127 markus 1450: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1451: >= sizeof(argv0) - 1) {
1.127 markus 1452: errno = EINVAL;
1.1 markus 1453: perror(shell);
1454: exit(1);
1.127 markus 1455: }
1.1 markus 1456:
1.127 markus 1457: /* Execute the shell. */
1458: argv[0] = argv0;
1459: argv[1] = NULL;
1460: execve(shell, argv, env);
1461:
1462: /* Executing the shell failed. */
1463: perror(shell);
1464: exit(1);
1.1 markus 1465: }
1466: /*
1467: * Execute the command using the user's shell. This uses the -c
1468: * option to execute the command.
1469: */
1.127 markus 1470: argv[0] = (char *) shell0;
1.1 markus 1471: argv[1] = "-c";
1472: argv[2] = (char *) command;
1473: argv[3] = NULL;
1474: execve(shell, argv, env);
1475: perror(shell);
1476: exit(1);
1477: }
1478:
1.237 djm 1479: void
1480: session_unused(int id)
1481: {
1482: debug3("%s: session id %d unused", __func__, id);
1483: if (id >= options.max_sessions ||
1484: id >= sessions_nalloc) {
1485: fatal("%s: insane session id %d (max %d nalloc %d)",
1486: __func__, id, options.max_sessions, sessions_nalloc);
1487: }
1488: bzero(&sessions[id], sizeof(*sessions));
1489: sessions[id].self = id;
1490: sessions[id].used = 0;
1491: sessions[id].chanid = -1;
1492: sessions[id].ptyfd = -1;
1493: sessions[id].ttyfd = -1;
1494: sessions[id].ptymaster = -1;
1495: sessions[id].x11_chanids = NULL;
1496: sessions[id].next_unused = sessions_first_unused;
1497: sessions_first_unused = id;
1498: }
1499:
1.1 markus 1500: Session *
1501: session_new(void)
1502: {
1.237 djm 1503: Session *s, *tmp;
1504:
1505: if (sessions_first_unused == -1) {
1506: if (sessions_nalloc >= options.max_sessions)
1507: return NULL;
1508: debug2("%s: allocate (allocated %d max %d)",
1509: __func__, sessions_nalloc, options.max_sessions);
1510: tmp = xrealloc(sessions, sessions_nalloc + 1,
1511: sizeof(*sessions));
1512: if (tmp == NULL) {
1513: error("%s: cannot allocate %d sessions",
1514: __func__, sessions_nalloc + 1);
1515: return NULL;
1516: }
1517: sessions = tmp;
1518: session_unused(sessions_nalloc++);
1519: }
1520:
1521: if (sessions_first_unused >= sessions_nalloc ||
1522: sessions_first_unused < 0) {
1523: fatal("%s: insane first_unused %d max %d nalloc %d",
1524: __func__, sessions_first_unused, options.max_sessions,
1525: sessions_nalloc);
1526: }
1527:
1528: s = &sessions[sessions_first_unused];
1529: if (s->used) {
1530: fatal("%s: session %d already used",
1531: __func__, sessions_first_unused);
1532: }
1533: sessions_first_unused = s->next_unused;
1534: s->used = 1;
1535: s->next_unused = -1;
1536: debug("session_new: session %d", s->self);
1537:
1538: return s;
1.1 markus 1539: }
1540:
1.94 itojun 1541: static void
1.1 markus 1542: session_dump(void)
1543: {
1544: int i;
1.237 djm 1545: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1546: Session *s = &sessions[i];
1.237 djm 1547:
1548: debug("dump: used %d next_unused %d session %d %p "
1549: "channel %d pid %ld",
1.1 markus 1550: s->used,
1.237 djm 1551: s->next_unused,
1.1 markus 1552: s->self,
1553: s,
1554: s->chanid,
1.137 mpech 1555: (long)s->pid);
1.1 markus 1556: }
1557: }
1558:
1.2 markus 1559: int
1.97 markus 1560: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1561: {
1562: Session *s = session_new();
1563: debug("session_open: channel %d", chanid);
1564: if (s == NULL) {
1565: error("no more sessions");
1566: return 0;
1567: }
1.97 markus 1568: s->authctxt = authctxt;
1569: s->pw = authctxt->pw;
1.167 djm 1570: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1571: fatal("no user for session %d", s->self);
1.2 markus 1572: debug("session_open: session %d: link with channel %d", s->self, chanid);
1573: s->chanid = chanid;
1574: return 1;
1575: }
1576:
1.130 provos 1577: Session *
1578: session_by_tty(char *tty)
1579: {
1580: int i;
1.237 djm 1581: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1582: Session *s = &sessions[i];
1583: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1584: debug("session_by_tty: session %d tty %s", i, tty);
1585: return s;
1586: }
1587: }
1588: debug("session_by_tty: unknown tty %.100s", tty);
1589: session_dump();
1590: return NULL;
1591: }
1592:
1.94 itojun 1593: static Session *
1.2 markus 1594: session_by_channel(int id)
1595: {
1596: int i;
1.237 djm 1597: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1598: Session *s = &sessions[i];
1599: if (s->used && s->chanid == id) {
1.237 djm 1600: debug("session_by_channel: session %d channel %d",
1601: i, id);
1.2 markus 1602: return s;
1603: }
1604: }
1605: debug("session_by_channel: unknown channel %d", id);
1606: session_dump();
1607: return NULL;
1608: }
1609:
1.94 itojun 1610: static Session *
1.184 djm 1611: session_by_x11_channel(int id)
1612: {
1613: int i, j;
1614:
1.237 djm 1615: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1616: Session *s = &sessions[i];
1617:
1618: if (s->x11_chanids == NULL || !s->used)
1619: continue;
1620: for (j = 0; s->x11_chanids[j] != -1; j++) {
1621: if (s->x11_chanids[j] == id) {
1622: debug("session_by_x11_channel: session %d "
1623: "channel %d", s->self, id);
1624: return s;
1625: }
1626: }
1627: }
1628: debug("session_by_x11_channel: unknown channel %d", id);
1629: session_dump();
1630: return NULL;
1631: }
1632:
1633: static Session *
1.2 markus 1634: session_by_pid(pid_t pid)
1635: {
1636: int i;
1.137 mpech 1637: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1638: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1639: Session *s = &sessions[i];
1640: if (s->used && s->pid == pid)
1641: return s;
1642: }
1.137 mpech 1643: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1644: session_dump();
1645: return NULL;
1646: }
1647:
1.94 itojun 1648: static int
1.2 markus 1649: session_window_change_req(Session *s)
1650: {
1651: s->col = packet_get_int();
1652: s->row = packet_get_int();
1653: s->xpixel = packet_get_int();
1654: s->ypixel = packet_get_int();
1.116 markus 1655: packet_check_eom();
1.2 markus 1656: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1657: return 1;
1658: }
1659:
1.94 itojun 1660: static int
1.2 markus 1661: session_pty_req(Session *s)
1662: {
1.45 markus 1663: u_int len;
1.72 stevesk 1664: int n_bytes;
1.132 markus 1665:
1.86 markus 1666: if (no_pty_flag) {
1667: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1668: return 0;
1.86 markus 1669: }
1670: if (s->ttyfd != -1) {
1671: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1672: return 0;
1.86 markus 1673: }
1674:
1.2 markus 1675: s->term = packet_get_string(&len);
1.86 markus 1676:
1677: if (compat20) {
1678: s->col = packet_get_int();
1679: s->row = packet_get_int();
1680: } else {
1681: s->row = packet_get_int();
1682: s->col = packet_get_int();
1683: }
1.2 markus 1684: s->xpixel = packet_get_int();
1685: s->ypixel = packet_get_int();
1686:
1687: if (strcmp(s->term, "") == 0) {
1688: xfree(s->term);
1689: s->term = NULL;
1690: }
1.86 markus 1691:
1.2 markus 1692: /* Allocate a pty and open it. */
1.86 markus 1693: debug("Allocating pty.");
1.237 djm 1694: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1695: sizeof(s->tty)))) {
1.86 markus 1696: if (s->term)
1697: xfree(s->term);
1.2 markus 1698: s->term = NULL;
1699: s->ptyfd = -1;
1700: s->ttyfd = -1;
1701: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1702: return 0;
1.2 markus 1703: }
1704: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1705:
1706: /* for SSH1 the tty modes length is not given */
1707: if (!compat20)
1708: n_bytes = packet_remaining();
1709: tty_parse_modes(s->ttyfd, &n_bytes);
1710:
1.130 provos 1711: if (!use_privsep)
1712: pty_setowner(s->pw, s->tty);
1.86 markus 1713:
1714: /* Set window size from the packet. */
1.2 markus 1715: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1716:
1.116 markus 1717: packet_check_eom();
1.9 markus 1718: session_proctitle(s);
1.2 markus 1719: return 1;
1720: }
1721:
1.94 itojun 1722: static int
1.7 markus 1723: session_subsystem_req(Session *s)
1724: {
1.105 markus 1725: struct stat st;
1.45 markus 1726: u_int len;
1.7 markus 1727: int success = 0;
1.205 djm 1728: char *prog, *cmd, *subsys = packet_get_string(&len);
1.182 djm 1729: u_int i;
1.7 markus 1730:
1.116 markus 1731: packet_check_eom();
1.255 djm 1732: logit("subsystem request for %.100s by user %s", subsys,
1733: s->pw->pw_name);
1.18 jakob 1734:
1735: for (i = 0; i < options.num_subsystems; i++) {
1.105 markus 1736: if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1737: prog = options.subsystem_command[i];
1738: cmd = options.subsystem_args[i];
1.249 dtucker 1739: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1740: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1741: debug("subsystem: %s", prog);
1.225 markus 1742: } else {
1.249 dtucker 1743: if (stat(prog, &st) < 0)
1744: debug("subsystem: cannot stat %s: %s",
1745: prog, strerror(errno));
1.225 markus 1746: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1747: debug("subsystem: exec() %s", cmd);
1.105 markus 1748: }
1.237 djm 1749: success = do_exec(s, cmd) == 0;
1.122 markus 1750: break;
1.18 jakob 1751: }
1752: }
1753:
1754: if (!success)
1.155 itojun 1755: logit("subsystem request for %.100s failed, subsystem not found",
1.105 markus 1756: subsys);
1.7 markus 1757:
1758: xfree(subsys);
1759: return success;
1760: }
1761:
1.94 itojun 1762: static int
1.7 markus 1763: session_x11_req(Session *s)
1764: {
1.81 markus 1765: int success;
1.7 markus 1766:
1.184 djm 1767: if (s->auth_proto != NULL || s->auth_data != NULL) {
1768: error("session_x11_req: session %d: "
1.190 stevesk 1769: "x11 forwarding already active", s->self);
1.184 djm 1770: return 0;
1771: }
1.7 markus 1772: s->single_connection = packet_get_char();
1773: s->auth_proto = packet_get_string(NULL);
1774: s->auth_data = packet_get_string(NULL);
1775: s->screen = packet_get_int();
1.116 markus 1776: packet_check_eom();
1.7 markus 1777:
1.81 markus 1778: success = session_setup_x11fwd(s);
1779: if (!success) {
1.7 markus 1780: xfree(s->auth_proto);
1781: xfree(s->auth_data);
1.84 markus 1782: s->auth_proto = NULL;
1783: s->auth_data = NULL;
1.7 markus 1784: }
1.81 markus 1785: return success;
1.7 markus 1786: }
1787:
1.94 itojun 1788: static int
1.19 markus 1789: session_shell_req(Session *s)
1790: {
1.116 markus 1791: packet_check_eom();
1.237 djm 1792: return do_exec(s, NULL) == 0;
1.19 markus 1793: }
1794:
1.94 itojun 1795: static int
1.19 markus 1796: session_exec_req(Session *s)
1797: {
1.237 djm 1798: u_int len, success;
1799:
1.19 markus 1800: char *command = packet_get_string(&len);
1.116 markus 1801: packet_check_eom();
1.237 djm 1802: success = do_exec(s, command) == 0;
1.92 markus 1803: xfree(command);
1.237 djm 1804: return success;
1.19 markus 1805: }
1806:
1.94 itojun 1807: static int
1.157 markus 1808: session_break_req(Session *s)
1809: {
1810:
1.175 deraadt 1811: packet_get_int(); /* ignored */
1.157 markus 1812: packet_check_eom();
1813:
1.237 djm 1814: if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
1.157 markus 1815: return 0;
1816: return 1;
1817: }
1818:
1819: static int
1.173 djm 1820: session_env_req(Session *s)
1821: {
1822: char *name, *val;
1823: u_int name_len, val_len, i;
1824:
1825: name = packet_get_string(&name_len);
1826: val = packet_get_string(&val_len);
1827: packet_check_eom();
1828:
1829: /* Don't set too many environment variables */
1830: if (s->num_env > 128) {
1831: debug2("Ignoring env request %s: too many env vars", name);
1832: goto fail;
1833: }
1834:
1835: for (i = 0; i < options.num_accept_env; i++) {
1836: if (match_pattern(name, options.accept_env[i])) {
1837: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.201 djm 1838: s->env = xrealloc(s->env, s->num_env + 1,
1839: sizeof(*s->env));
1.173 djm 1840: s->env[s->num_env].name = name;
1841: s->env[s->num_env].val = val;
1842: s->num_env++;
1843: return (1);
1844: }
1845: }
1846: debug2("Ignoring env request %s: disallowed name", name);
1847:
1848: fail:
1849: xfree(name);
1850: xfree(val);
1851: return (0);
1852: }
1853:
1854: static int
1.43 markus 1855: session_auth_agent_req(Session *s)
1856: {
1857: static int called = 0;
1.116 markus 1858: packet_check_eom();
1.235 pyr 1859: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1860: debug("session_auth_agent_req: no_agent_forwarding_flag");
1861: return 0;
1862: }
1.43 markus 1863: if (called) {
1864: return 0;
1865: } else {
1866: called = 1;
1867: return auth_input_request_forwarding(s->pw);
1868: }
1869: }
1870:
1.123 markus 1871: int
1872: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1873: {
1874: int success = 0;
1875: Session *s;
1876:
1.123 markus 1877: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1878: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1879: c->self, rtype);
1880: return 0;
1881: }
1882: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1883:
1884: /*
1.64 markus 1885: * a session is in LARVAL state until a shell, a command
1886: * or a subsystem is executed
1.2 markus 1887: */
1888: if (c->type == SSH_CHANNEL_LARVAL) {
1889: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1890: success = session_shell_req(s);
1.2 markus 1891: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1892: success = session_exec_req(s);
1.2 markus 1893: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1894: success = session_pty_req(s);
1.7 markus 1895: } else if (strcmp(rtype, "x11-req") == 0) {
1896: success = session_x11_req(s);
1.43 markus 1897: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1898: success = session_auth_agent_req(s);
1.7 markus 1899: } else if (strcmp(rtype, "subsystem") == 0) {
1900: success = session_subsystem_req(s);
1.173 djm 1901: } else if (strcmp(rtype, "env") == 0) {
1902: success = session_env_req(s);
1.2 markus 1903: }
1904: }
1905: if (strcmp(rtype, "window-change") == 0) {
1906: success = session_window_change_req(s);
1.177 djm 1907: } else if (strcmp(rtype, "break") == 0) {
1908: success = session_break_req(s);
1.2 markus 1909: }
1.177 djm 1910:
1.123 markus 1911: return success;
1.2 markus 1912: }
1913:
1914: void
1.256 djm 1915: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1916: int is_tty)
1.2 markus 1917: {
1918: if (!compat20)
1919: fatal("session_set_fds: called for proto != 2.0");
1920: /*
1921: * now that have a child and a pipe to the child,
1922: * we can activate our channel and register the fd's
1923: */
1924: if (s->chanid == -1)
1925: fatal("no channel for session %d", s->self);
1926: channel_set_fds(s->chanid,
1927: fdout, fdin, fderr,
1.256 djm 1928: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1929: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1930: }
1931:
1.85 markus 1932: /*
1933: * Function to perform pty cleanup. Also called if we get aborted abnormally
1934: * (e.g., due to a dropped connection).
1935: */
1.130 provos 1936: void
1.165 markus 1937: session_pty_cleanup2(Session *s)
1.1 markus 1938: {
1.85 markus 1939: if (s == NULL) {
1940: error("session_pty_cleanup: no session");
1941: return;
1942: }
1943: if (s->ttyfd == -1)
1.1 markus 1944: return;
1945:
1.54 stevesk 1946: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1947:
1948: /* Record that the user has logged out. */
1.85 markus 1949: if (s->pid != 0)
1950: record_logout(s->pid, s->tty);
1.1 markus 1951:
1952: /* Release the pseudo-tty. */
1.130 provos 1953: if (getuid() == 0)
1954: pty_release(s->tty);
1.1 markus 1955:
1956: /*
1957: * Close the server side of the socket pairs. We must do this after
1958: * the pty cleanup, so that another process doesn't get this pty
1959: * while we're still cleaning up.
1960: */
1.237 djm 1961: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
1962: error("close(s->ptymaster/%d): %s",
1963: s->ptymaster, strerror(errno));
1.108 markus 1964:
1965: /* unlink pty from session */
1966: s->ttyfd = -1;
1.2 markus 1967: }
1968:
1.130 provos 1969: void
1.165 markus 1970: session_pty_cleanup(Session *s)
1.130 provos 1971: {
1.165 markus 1972: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 1973: }
1974:
1.147 markus 1975: static char *
1976: sig2name(int sig)
1977: {
1978: #define SSH_SIG(x) if (sig == SIG ## x) return #x
1979: SSH_SIG(ABRT);
1980: SSH_SIG(ALRM);
1981: SSH_SIG(FPE);
1982: SSH_SIG(HUP);
1983: SSH_SIG(ILL);
1984: SSH_SIG(INT);
1985: SSH_SIG(KILL);
1986: SSH_SIG(PIPE);
1987: SSH_SIG(QUIT);
1988: SSH_SIG(SEGV);
1989: SSH_SIG(TERM);
1990: SSH_SIG(USR1);
1991: SSH_SIG(USR2);
1992: #undef SSH_SIG
1993: return "SIG@openssh.com";
1994: }
1995:
1.94 itojun 1996: static void
1.184 djm 1997: session_close_x11(int id)
1998: {
1999: Channel *c;
2000:
1.189 markus 2001: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2002: debug("session_close_x11: x11 channel %d missing", id);
2003: } else {
2004: /* Detach X11 listener */
2005: debug("session_close_x11: detach x11 channel %d", id);
2006: channel_cancel_cleanup(id);
2007: if (c->ostate != CHAN_OUTPUT_CLOSED)
2008: chan_mark_dead(c);
2009: }
2010: }
2011:
2012: static void
2013: session_close_single_x11(int id, void *arg)
2014: {
2015: Session *s;
2016: u_int i;
2017:
2018: debug3("session_close_single_x11: channel %d", id);
2019: channel_cancel_cleanup(id);
1.221 stevesk 2020: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2021: fatal("session_close_single_x11: no x11 channel %d", id);
2022: for (i = 0; s->x11_chanids[i] != -1; i++) {
2023: debug("session_close_single_x11: session %d: "
2024: "closing channel %d", s->self, s->x11_chanids[i]);
2025: /*
2026: * The channel "id" is already closing, but make sure we
2027: * close all of its siblings.
2028: */
2029: if (s->x11_chanids[i] != id)
2030: session_close_x11(s->x11_chanids[i]);
2031: }
2032: xfree(s->x11_chanids);
2033: s->x11_chanids = NULL;
2034: if (s->display) {
2035: xfree(s->display);
2036: s->display = NULL;
2037: }
2038: if (s->auth_proto) {
2039: xfree(s->auth_proto);
2040: s->auth_proto = NULL;
2041: }
2042: if (s->auth_data) {
2043: xfree(s->auth_data);
2044: s->auth_data = NULL;
2045: }
2046: if (s->auth_display) {
2047: xfree(s->auth_display);
2048: s->auth_display = NULL;
2049: }
2050: }
2051:
2052: static void
1.2 markus 2053: session_exit_message(Session *s, int status)
2054: {
2055: Channel *c;
1.124 markus 2056:
2057: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2058: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2059: s->self, s->chanid);
1.137 mpech 2060: debug("session_exit_message: session %d channel %d pid %ld",
2061: s->self, s->chanid, (long)s->pid);
1.2 markus 2062:
2063: if (WIFEXITED(status)) {
1.124 markus 2064: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2065: packet_put_int(WEXITSTATUS(status));
2066: packet_send();
2067: } else if (WIFSIGNALED(status)) {
1.124 markus 2068: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2069: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2070: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2071: packet_put_cstring("");
2072: packet_put_cstring("");
2073: packet_send();
2074: } else {
2075: /* Some weird exit cause. Just exit. */
2076: packet_disconnect("wait returned status %04x.", status);
2077: }
2078:
2079: /* disconnect channel */
2080: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2081:
2082: /*
2083: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2084: * the channel gets EOF. The session will be then be closed
1.187 djm 2085: * by session_close_by_channel when the childs close their fds.
2086: */
2087: channel_register_cleanup(c->self, session_close_by_channel, 1);
2088:
1.5 markus 2089: /*
2090: * emulate a write failure with 'chan_write_failed', nobody will be
2091: * interested in data we write.
2092: * Note that we must not call 'chan_read_failed', since there could
2093: * be some more data waiting in the pipe.
2094: */
1.8 markus 2095: if (c->ostate != CHAN_OUTPUT_CLOSED)
2096: chan_write_failed(c);
1.2 markus 2097: }
2098:
1.130 provos 2099: void
1.85 markus 2100: session_close(Session *s)
1.2 markus 2101: {
1.182 djm 2102: u_int i;
1.173 djm 2103:
1.137 mpech 2104: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165 markus 2105: if (s->ttyfd != -1)
1.85 markus 2106: session_pty_cleanup(s);
1.2 markus 2107: if (s->term)
2108: xfree(s->term);
2109: if (s->display)
2110: xfree(s->display);
1.184 djm 2111: if (s->x11_chanids)
2112: xfree(s->x11_chanids);
1.118 stevesk 2113: if (s->auth_display)
2114: xfree(s->auth_display);
1.2 markus 2115: if (s->auth_data)
2116: xfree(s->auth_data);
2117: if (s->auth_proto)
2118: xfree(s->auth_proto);
1.219 djm 2119: if (s->env != NULL) {
2120: for (i = 0; i < s->num_env; i++) {
2121: xfree(s->env[i].name);
2122: xfree(s->env[i].val);
2123: }
2124: xfree(s->env);
1.173 djm 2125: }
1.9 markus 2126: session_proctitle(s);
1.237 djm 2127: session_unused(s->self);
1.2 markus 2128: }
2129:
2130: void
2131: session_close_by_pid(pid_t pid, int status)
2132: {
2133: Session *s = session_by_pid(pid);
2134: if (s == NULL) {
1.137 mpech 2135: debug("session_close_by_pid: no session for pid %ld",
2136: (long)pid);
1.2 markus 2137: return;
2138: }
2139: if (s->chanid != -1)
2140: session_exit_message(s, status);
1.187 djm 2141: if (s->ttyfd != -1)
2142: session_pty_cleanup(s);
1.197 djm 2143: s->pid = 0;
1.98 markus 2144: }
2145:
1.2 markus 2146: /*
2147: * this is called when a channel dies before
2148: * the session 'child' itself dies
2149: */
2150: void
2151: session_close_by_channel(int id, void *arg)
2152: {
2153: Session *s = session_by_channel(id);
1.187 djm 2154: u_int i;
1.184 djm 2155:
1.2 markus 2156: if (s == NULL) {
1.107 markus 2157: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2158: return;
2159: }
1.137 mpech 2160: debug("session_close_by_channel: channel %d child %ld",
2161: id, (long)s->pid);
1.107 markus 2162: if (s->pid != 0) {
2163: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2164: /*
2165: * delay detach of session, but release pty, since
2166: * the fd's to the child are already closed
2167: */
1.165 markus 2168: if (s->ttyfd != -1)
1.108 markus 2169: session_pty_cleanup(s);
1.107 markus 2170: return;
2171: }
2172: /* detach by removing callback */
1.2 markus 2173: channel_cancel_cleanup(s->chanid);
1.187 djm 2174:
2175: /* Close any X11 listeners associated with this session */
2176: if (s->x11_chanids != NULL) {
2177: for (i = 0; s->x11_chanids[i] != -1; i++) {
2178: session_close_x11(s->x11_chanids[i]);
2179: s->x11_chanids[i] = -1;
2180: }
2181: }
2182:
1.2 markus 2183: s->chanid = -1;
1.106 markus 2184: session_close(s);
2185: }
2186:
2187: void
1.130 provos 2188: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2189: {
2190: int i;
1.237 djm 2191: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2192: Session *s = &sessions[i];
1.130 provos 2193: if (s->used) {
2194: if (closefunc != NULL)
2195: closefunc(s);
2196: else
2197: session_close(s);
2198: }
1.2 markus 2199: }
1.9 markus 2200: }
2201:
1.94 itojun 2202: static char *
1.9 markus 2203: session_tty_list(void)
2204: {
2205: static char buf[1024];
2206: int i;
2207: buf[0] = '\0';
1.237 djm 2208: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2209: Session *s = &sessions[i];
2210: if (s->used && s->ttyfd != -1) {
2211: if (buf[0] != '\0')
2212: strlcat(buf, ",", sizeof buf);
2213: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2214: }
2215: }
2216: if (buf[0] == '\0')
2217: strlcpy(buf, "notty", sizeof buf);
2218: return buf;
2219: }
2220:
2221: void
2222: session_proctitle(Session *s)
2223: {
2224: if (s->pw == NULL)
2225: error("no user for session %d", s->self);
2226: else
2227: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2228: }
2229:
2230: int
2231: session_setup_x11fwd(Session *s)
2232: {
2233: struct stat st;
1.109 stevesk 2234: char display[512], auth_display[512];
2235: char hostname[MAXHOSTNAMELEN];
1.184 djm 2236: u_int i;
1.81 markus 2237:
2238: if (no_x11_forwarding_flag) {
2239: packet_send_debug("X11 forwarding disabled in user configuration file.");
2240: return 0;
2241: }
2242: if (!options.x11_forwarding) {
2243: debug("X11 forwarding disabled in server configuration file.");
2244: return 0;
2245: }
2246: if (!options.xauth_location ||
2247: (stat(options.xauth_location, &st) == -1)) {
2248: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2249: return 0;
2250: }
2251: if (options.use_login) {
2252: packet_send_debug("X11 forwarding disabled; "
2253: "not compatible with UseLogin=yes.");
1.81 markus 2254: return 0;
2255: }
1.87 markus 2256: if (s->display != NULL) {
1.81 markus 2257: debug("X11 display already set.");
2258: return 0;
2259: }
1.140 deraadt 2260: if (x11_create_display_inet(options.x11_display_offset,
2261: options.x11_use_localhost, s->single_connection,
1.184 djm 2262: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2263: debug("x11_create_display_inet failed.");
1.81 markus 2264: return 0;
1.184 djm 2265: }
2266: for (i = 0; s->x11_chanids[i] != -1; i++) {
2267: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2268: session_close_single_x11, 0);
1.81 markus 2269: }
1.109 stevesk 2270:
2271: /* Set up a suitable value for the DISPLAY variable. */
2272: if (gethostname(hostname, sizeof(hostname)) < 0)
2273: fatal("gethostname: %.100s", strerror(errno));
2274: /*
2275: * auth_display must be used as the displayname when the
2276: * authorization entry is added with xauth(1). This will be
2277: * different than the DISPLAY string for localhost displays.
2278: */
1.119 stevesk 2279: if (options.x11_use_localhost) {
1.140 deraadt 2280: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2281: s->display_number, s->screen);
1.140 deraadt 2282: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2283: s->display_number, s->screen);
1.109 stevesk 2284: s->display = xstrdup(display);
1.118 stevesk 2285: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2286: } else {
1.140 deraadt 2287: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2288: s->display_number, s->screen);
2289: s->display = xstrdup(display);
1.118 stevesk 2290: s->auth_display = xstrdup(display);
1.109 stevesk 2291: }
2292:
1.81 markus 2293: return 1;
1.2 markus 2294: }
2295:
1.94 itojun 2296: static void
1.49 markus 2297: do_authenticated2(Authctxt *authctxt)
1.2 markus 2298: {
1.97 markus 2299: server_loop2(authctxt);
1.165 markus 2300: }
2301:
2302: void
2303: do_cleanup(Authctxt *authctxt)
2304: {
2305: static int called = 0;
2306:
2307: debug("do_cleanup");
2308:
2309: /* no cleanup if we're in the child for login shell */
2310: if (is_child)
2311: return;
2312:
2313: /* avoid double cleanup */
2314: if (called)
2315: return;
2316: called = 1;
2317:
1.218 markus 2318: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2319: return;
2320: #ifdef KRB5
2321: if (options.kerberos_ticket_cleanup &&
2322: authctxt->krb5_ctx)
2323: krb5_cleanup_proc(authctxt);
1.161 markus 2324: #endif
1.165 markus 2325:
2326: #ifdef GSSAPI
2327: if (compat20 && options.gss_cleanup_creds)
2328: ssh_gssapi_cleanup_creds();
2329: #endif
2330:
2331: /* remove agent socket */
2332: auth_sock_cleanup_proc(authctxt->pw);
2333:
2334: /*
2335: * Cleanup ptys/utmp only if privsep is disabled,
2336: * or if running in monitor.
2337: */
2338: if (!use_privsep || mm_is_monitor())
2339: session_destroy_all(session_pty_cleanup2);
1.1 markus 2340: }
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