Annotation of src/usr.bin/ssh/session.c, Revision 1.253
1.253 ! djm 1: /* $OpenBSD: session.c,v 1.252 2010/03/07 11:57:13 dtucker 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);
1.240 djm 100: void session_set_fds(Session *, 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: }
1.253 ! djm 451: if (s->is_subsystem) {
! 452: if ((perr[1] = open(_PATH_DEVNULL, O_WRONLY)) == -1) {
! 453: error("%s: open(%s): %s", __func__, _PATH_DEVNULL,
! 454: strerror(errno));
! 455: close(pin[0]);
! 456: close(pin[1]);
! 457: close(pout[0]);
! 458: close(pout[1]);
! 459: return -1;
! 460: }
! 461: perr[0] = -1;
! 462: } else {
! 463: if (pipe(perr) < 0) {
! 464: error("%s: pipe err: %.100s", __func__,
! 465: strerror(errno));
! 466: close(pin[0]);
! 467: close(pin[1]);
! 468: close(pout[0]);
! 469: close(pout[1]);
! 470: return -1;
! 471: }
1.238 markus 472: }
473: #else
1.237 djm 474: int inout[2], err[2];
1.1 markus 475:
1.253 ! djm 476: if (s == NULL)
! 477: fatal("do_exec_no_pty: no session");
! 478:
1.1 markus 479: /* Uses socket pairs to communicate with the program. */
1.237 djm 480: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
481: error("%s: socketpair #1: %.100s", __func__, strerror(errno));
482: return -1;
483: }
1.253 ! djm 484: if (s->is_subsystem) {
! 485: if ((err[0] = open(_PATH_DEVNULL, O_WRONLY)) == -1) {
! 486: error("%s: open(%s): %s", __func__, _PATH_DEVNULL,
! 487: strerror(errno));
! 488: close(inout[0]);
! 489: close(inout[1]);
! 490: return -1;
! 491: }
! 492: err[1] = -1;
! 493: } else {
! 494: if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
! 495: error("%s: socketpair #2: %.100s", __func__,
! 496: strerror(errno));
! 497: close(inout[0]);
! 498: close(inout[1]);
! 499: return -1;
! 500: }
1.237 djm 501: }
1.238 markus 502: #endif
1.237 djm 503:
1.9 markus 504: session_proctitle(s);
1.1 markus 505:
506: /* Fork the child. */
1.237 djm 507: switch ((pid = fork())) {
508: case -1:
509: error("%s: fork: %.100s", __func__, strerror(errno));
1.238 markus 510: #ifdef USE_PIPES
511: close(pin[0]);
512: close(pin[1]);
513: close(pout[0]);
514: close(pout[1]);
1.253 ! djm 515: if (perr[0] != -1)
! 516: close(perr[0]);
1.238 markus 517: close(perr[1]);
518: #else
1.237 djm 519: close(inout[0]);
520: close(inout[1]);
521: close(err[0]);
1.253 ! djm 522: if (err[1] != -1)
! 523: close(err[1]);
1.238 markus 524: #endif
1.237 djm 525: return -1;
526: case 0:
1.165 markus 527: is_child = 1;
1.144 markus 528:
1.1 markus 529: /* Child. Reinitialize the log since the pid has changed. */
1.237 djm 530: log_init(__progname, options.log_level,
531: options.log_facility, log_stderr);
1.1 markus 532:
533: /*
534: * Create a new session and process group since the 4.4BSD
535: * setlogin() affects the entire process group.
536: */
537: if (setsid() < 0)
538: error("setsid failed: %.100s", strerror(errno));
539:
1.238 markus 540: #ifdef USE_PIPES
541: /*
542: * Redirect stdin. We close the parent side of the socket
543: * pair, and make the child side the standard input.
544: */
545: close(pin[1]);
546: if (dup2(pin[0], 0) < 0)
547: perror("dup2 stdin");
548: close(pin[0]);
549:
550: /* Redirect stdout. */
551: close(pout[0]);
552: if (dup2(pout[1], 1) < 0)
553: perror("dup2 stdout");
554: close(pout[1]);
555:
556: /* Redirect stderr. */
1.253 ! djm 557: if (perr[0] != -1)
! 558: close(perr[0]);
1.238 markus 559: if (dup2(perr[1], 2) < 0)
560: perror("dup2 stderr");
561: close(perr[1]);
562: #else
1.1 markus 563: /*
564: * Redirect stdin, stdout, and stderr. Stdin and stdout will
565: * use the same socket, as some programs (particularly rdist)
566: * seem to depend on it.
567: */
568: close(inout[1]);
1.253 ! djm 569: if (err[1] != -1)
! 570: close(err[1]);
1.1 markus 571: if (dup2(inout[0], 0) < 0) /* stdin */
572: perror("dup2 stdin");
1.237 djm 573: if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
1.1 markus 574: perror("dup2 stdout");
1.238 markus 575: close(inout[0]);
1.1 markus 576: if (dup2(err[0], 2) < 0) /* stderr */
577: perror("dup2 stderr");
1.238 markus 578: close(err[0]);
579: #endif
1.1 markus 580:
581: /* Do processing for the child (exec command etc). */
1.60 markus 582: do_child(s, command);
1.1 markus 583: /* NOTREACHED */
1.237 djm 584: default:
585: break;
1.1 markus 586: }
1.237 djm 587:
1.1 markus 588: s->pid = pid;
1.47 markus 589: /* Set interactive/non-interactive mode. */
1.48 markus 590: packet_set_interactive(s->display != NULL);
1.1 markus 591:
1.238 markus 592: #ifdef USE_PIPES
593: /* We are the parent. Close the child sides of the pipes. */
594: close(pin[0]);
595: close(pout[1]);
596: close(perr[1]);
597:
598: if (compat20) {
1.240 djm 599: session_set_fds(s, pin[1], pout[0], perr[0], 0);
1.238 markus 600: } else {
601: /* Enter the interactive session. */
602: server_loop(pid, pin[1], pout[0], perr[0]);
603: /* server_loop has closed pin[1], pout[0], and perr[0]. */
604: }
605: #else
1.1 markus 606: /* We are the parent. Close the child sides of the socket pairs. */
607: close(inout[0]);
608: close(err[0]);
609:
610: /*
611: * Enter the interactive session. Note: server_loop must be able to
612: * handle the case that fdin and fdout are the same.
613: */
1.2 markus 614: if (compat20) {
1.253 ! djm 615: session_set_fds(s, inout[1], inout[1], err[1], 0);
1.2 markus 616: } else {
617: server_loop(pid, inout[1], inout[1], err[1]);
618: /* server_loop has closed inout[1] and err[1]. */
619: }
1.238 markus 620: #endif
1.237 djm 621: return 0;
1.1 markus 622: }
623:
624: /*
625: * This is called to fork and execute a command when we have a tty. This
626: * will call do_child from the child, and server_loop from the parent after
627: * setting up file descriptors, controlling tty, updating wtmp, utmp,
628: * lastlog, and other such operations.
629: */
1.237 djm 630: int
1.63 markus 631: do_exec_pty(Session *s, const char *command)
1.1 markus 632: {
633: int fdout, ptyfd, ttyfd, ptymaster;
634: pid_t pid;
635:
636: if (s == NULL)
637: fatal("do_exec_pty: no session");
638: ptyfd = s->ptyfd;
639: ttyfd = s->ttyfd;
640:
1.237 djm 641: /*
642: * Create another descriptor of the pty master side for use as the
643: * standard input. We could use the original descriptor, but this
644: * simplifies code in server_loop. The descriptor is bidirectional.
645: * Do this before forking (and cleanup in the child) so as to
646: * detect and gracefully fail out-of-fd conditions.
647: */
648: if ((fdout = dup(ptyfd)) < 0) {
649: error("%s: dup #1: %s", __func__, strerror(errno));
650: close(ttyfd);
651: close(ptyfd);
652: return -1;
653: }
654: /* we keep a reference to the pty master */
655: if ((ptymaster = dup(ptyfd)) < 0) {
656: error("%s: dup #2: %s", __func__, strerror(errno));
657: close(ttyfd);
658: close(ptyfd);
659: close(fdout);
660: return -1;
661: }
662:
1.1 markus 663: /* Fork the child. */
1.237 djm 664: switch ((pid = fork())) {
665: case -1:
666: error("%s: fork: %.100s", __func__, strerror(errno));
667: close(fdout);
668: close(ptymaster);
669: close(ttyfd);
670: close(ptyfd);
671: return -1;
672: case 0:
1.165 markus 673: is_child = 1;
1.97 markus 674:
1.237 djm 675: close(fdout);
676: close(ptymaster);
677:
1.24 markus 678: /* Child. Reinitialize the log because the pid has changed. */
1.237 djm 679: log_init(__progname, options.log_level,
680: options.log_facility, log_stderr);
1.1 markus 681: /* Close the master side of the pseudo tty. */
682: close(ptyfd);
683:
684: /* Make the pseudo tty our controlling tty. */
685: pty_make_controlling_tty(&ttyfd, s->tty);
686:
1.103 markus 687: /* Redirect stdin/stdout/stderr from the pseudo tty. */
688: if (dup2(ttyfd, 0) < 0)
689: error("dup2 stdin: %s", strerror(errno));
690: if (dup2(ttyfd, 1) < 0)
691: error("dup2 stdout: %s", strerror(errno));
692: if (dup2(ttyfd, 2) < 0)
693: error("dup2 stderr: %s", strerror(errno));
1.1 markus 694:
695: /* Close the extra descriptor for the pseudo tty. */
696: close(ttyfd);
697:
1.24 markus 698: /* record login, etc. similar to login(1) */
1.41 markus 699: if (!(options.use_login && command == NULL))
700: do_login(s, command);
1.228 djm 701:
1.237 djm 702: /*
703: * Do common processing for the child, such as execing
704: * the command.
705: */
1.60 markus 706: do_child(s, command);
1.1 markus 707: /* NOTREACHED */
1.237 djm 708: default:
709: break;
1.1 markus 710: }
711: s->pid = pid;
712:
713: /* Parent. Close the slave side of the pseudo tty. */
714: close(ttyfd);
715:
1.237 djm 716: /* Enter interactive session. */
1.1 markus 717: s->ptymaster = ptymaster;
1.47 markus 718: packet_set_interactive(1);
1.2 markus 719: if (compat20) {
1.240 djm 720: session_set_fds(s, ptyfd, fdout, -1, 1);
1.2 markus 721: } else {
722: server_loop(pid, ptyfd, fdout, -1);
723: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 724: }
1.237 djm 725: return 0;
1.24 markus 726: }
727:
1.90 markus 728: /*
729: * This is called to fork and execute a command. If another command is
730: * to be forced, execute that instead.
731: */
1.237 djm 732: int
1.90 markus 733: do_exec(Session *s, const char *command)
734: {
1.237 djm 735: int ret;
736:
1.210 dtucker 737: if (options.adm_forced_command) {
738: original_command = command;
739: command = options.adm_forced_command;
1.248 djm 740: if (IS_INTERNAL_SFTP(command)) {
741: s->is_subsystem = s->is_subsystem ?
742: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
743: } else if (s->is_subsystem)
1.225 markus 744: s->is_subsystem = SUBSYSTEM_EXT;
1.210 dtucker 745: debug("Forced command (config) '%.900s'", command);
746: } else if (forced_command) {
1.90 markus 747: original_command = command;
748: command = forced_command;
1.248 djm 749: if (IS_INTERNAL_SFTP(command)) {
750: s->is_subsystem = s->is_subsystem ?
751: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
752: } else if (s->is_subsystem)
1.225 markus 753: s->is_subsystem = SUBSYSTEM_EXT;
1.210 dtucker 754: debug("Forced command (key option) '%.900s'", command);
1.90 markus 755: }
1.163 markus 756:
757: #ifdef GSSAPI
758: if (options.gss_authentication) {
759: temporarily_use_uid(s->pw);
760: ssh_gssapi_storecreds();
761: restore_uid();
762: }
763: #endif
1.90 markus 764: if (s->ttyfd != -1)
1.237 djm 765: ret = do_exec_pty(s, command);
1.90 markus 766: else
1.237 djm 767: ret = do_exec_no_pty(s, command);
1.90 markus 768:
1.92 markus 769: original_command = NULL;
1.179 dtucker 770:
771: /*
772: * Clear loginmsg: it's the child's responsibility to display
773: * it to the user, otherwise multiple sessions may accumulate
774: * multiple copies of the login messages.
775: */
776: buffer_clear(&loginmsg);
1.237 djm 777:
778: return ret;
1.90 markus 779: }
780:
781:
1.24 markus 782: /* administrative, login(1)-like work */
783: void
1.41 markus 784: do_login(Session *s, const char *command)
1.24 markus 785: {
786: socklen_t fromlen;
787: struct sockaddr_storage from;
788: struct passwd * pw = s->pw;
789: pid_t pid = getpid();
790:
791: /*
792: * Get IP address of client. If the connection is not a socket, let
793: * the address be 0.0.0.0.
794: */
795: memset(&from, 0, sizeof(from));
1.148 stevesk 796: fromlen = sizeof(from);
1.24 markus 797: if (packet_connection_is_on_socket()) {
798: if (getpeername(packet_get_connection_in(),
1.200 deraadt 799: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 800: debug("getpeername: %.100s", strerror(errno));
1.165 markus 801: cleanup_exit(255);
1.24 markus 802: }
803: }
1.25 markus 804:
1.24 markus 805: /* Record that there was a login on that tty from the remote host. */
1.133 markus 806: if (!use_privsep)
807: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
808: get_remote_name_or_ip(utmp_len,
1.158 markus 809: options.use_dns),
1.148 stevesk 810: (struct sockaddr *)&from, fromlen);
1.24 markus 811:
1.73 djm 812: if (check_quietlogin(s, command))
1.24 markus 813: return;
1.73 djm 814:
1.179 dtucker 815: display_loginmsg();
1.73 djm 816:
817: do_motd();
818: }
819:
820: /*
821: * Display the message of the day.
822: */
823: void
824: do_motd(void)
825: {
826: FILE *f;
827: char buf[256];
828:
1.24 markus 829: if (options.print_motd) {
1.28 millert 830: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
831: "/etc/motd"), "r");
1.24 markus 832: if (f) {
833: while (fgets(buf, sizeof(buf), f))
834: fputs(buf, stdout);
835: fclose(f);
836: }
1.2 markus 837: }
1.73 djm 838: }
839:
840:
841: /*
842: * Check for quiet login, either .hushlogin or command given.
843: */
844: int
845: check_quietlogin(Session *s, const char *command)
846: {
847: char buf[256];
1.96 dugsong 848: struct passwd *pw = s->pw;
1.73 djm 849: struct stat st;
850:
851: /* Return 1 if .hushlogin exists or a command given. */
852: if (command != NULL)
853: return 1;
854: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
855: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
856: return 1;
857: return 0;
1.1 markus 858: }
859:
860: /*
861: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 862: * already exists, its value is overridden.
1.1 markus 863: */
1.161 markus 864: void
1.45 markus 865: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 866: const char *value)
1.1 markus 867: {
1.164 markus 868: char **env;
869: u_int envsize;
1.45 markus 870: u_int i, namelen;
1.1 markus 871:
872: /*
873: * Find the slot where the value should be stored. If the variable
874: * already exists, we reuse the slot; otherwise we append a new slot
875: * at the end of the array, expanding if necessary.
876: */
877: env = *envp;
878: namelen = strlen(name);
879: for (i = 0; env[i]; i++)
880: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
881: break;
882: if (env[i]) {
883: /* Reuse the slot. */
884: xfree(env[i]);
885: } else {
886: /* New variable. Expand if necessary. */
1.164 markus 887: envsize = *envsizep;
888: if (i >= envsize - 1) {
889: if (envsize >= 1000)
890: fatal("child_set_env: too many env vars");
891: envsize += 50;
1.201 djm 892: env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1.164 markus 893: *envsizep = envsize;
1.1 markus 894: }
895: /* Need to set the NULL pointer at end of array beyond the new slot. */
896: env[i + 1] = NULL;
897: }
898:
899: /* Allocate space and format the variable in the appropriate slot. */
900: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
901: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
902: }
903:
904: /*
905: * Reads environment variables from the given file and adds/overrides them
906: * into the environment. If the file does not exist, this does nothing.
907: * Otherwise, it must consist of empty lines, comments (line starts with '#')
908: * and assignments of the form name=value. No other forms are allowed.
909: */
1.94 itojun 910: static void
1.45 markus 911: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 912: const char *filename)
1.1 markus 913: {
914: FILE *f;
915: char buf[4096];
916: char *cp, *value;
1.142 deraadt 917: u_int lineno = 0;
1.1 markus 918:
919: f = fopen(filename, "r");
920: if (!f)
921: return;
922:
923: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 924: if (++lineno > 1000)
925: fatal("Too many lines in environment file %s", filename);
1.1 markus 926: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
927: ;
928: if (!*cp || *cp == '#' || *cp == '\n')
929: continue;
1.224 gilles 930:
931: cp[strcspn(cp, "\n")] = '\0';
932:
1.1 markus 933: value = strchr(cp, '=');
934: if (value == NULL) {
1.142 deraadt 935: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
936: filename);
1.1 markus 937: continue;
938: }
1.14 deraadt 939: /*
940: * Replace the equals sign by nul, and advance value to
941: * the value string.
942: */
1.1 markus 943: *value = '\0';
944: value++;
945: child_set_env(env, envsize, cp, value);
946: }
947: fclose(f);
948: }
949:
1.127 markus 950: static char **
951: do_setup_env(Session *s, const char *shell)
1.1 markus 952: {
953: char buf[256];
1.127 markus 954: u_int i, envsize;
1.154 markus 955: char **env, *laddr;
1.127 markus 956: struct passwd *pw = s->pw;
1.1 markus 957:
958: /* Initialize the environment. */
959: envsize = 100;
1.220 djm 960: env = xcalloc(envsize, sizeof(char *));
1.1 markus 961: env[0] = NULL;
962:
1.161 markus 963: #ifdef GSSAPI
1.168 djm 964: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 965: * the childs environment as they see fit
966: */
967: ssh_gssapi_do_child(&env, &envsize);
968: #endif
969:
1.1 markus 970: if (!options.use_login) {
971: /* Set basic environment. */
1.173 djm 972: for (i = 0; i < s->num_env; i++)
1.178 deraadt 973: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 974: s->env[i].val);
975:
1.1 markus 976: child_set_env(&env, &envsize, "USER", pw->pw_name);
977: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
978: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 979: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
980: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
981: else
982: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 983:
984: snprintf(buf, sizeof buf, "%.200s/%.50s",
985: _PATH_MAILDIR, pw->pw_name);
986: child_set_env(&env, &envsize, "MAIL", buf);
987:
988: /* Normal systems set SHELL by default. */
989: child_set_env(&env, &envsize, "SHELL", shell);
990: }
991: if (getenv("TZ"))
992: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
993:
994: /* Set custom environment options from RSA authentication. */
1.110 markus 995: if (!options.use_login) {
996: while (custom_environment) {
997: struct envstring *ce = custom_environment;
1.143 deraadt 998: char *str = ce->s;
1.127 markus 999:
1.143 deraadt 1000: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 1001: ;
1.143 deraadt 1002: if (str[i] == '=') {
1003: str[i] = 0;
1004: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 1005: }
1006: custom_environment = ce->next;
1007: xfree(ce->s);
1008: xfree(ce);
1.1 markus 1009: }
1010: }
1011:
1.149 stevesk 1012: /* SSH_CLIENT deprecated */
1.1 markus 1013: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 1014: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 1015: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1016:
1.154 markus 1017: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1018: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 1019: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1020: xfree(laddr);
1.149 stevesk 1021: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1022:
1.60 markus 1023: if (s->ttyfd != -1)
1024: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1025: if (s->term)
1026: child_set_env(&env, &envsize, "TERM", s->term);
1027: if (s->display)
1028: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1029: if (original_command)
1030: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1031: original_command);
1.96 dugsong 1032: #ifdef KRB5
1033: if (s->authctxt->krb5_ticket_file)
1034: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1035: s->authctxt->krb5_ticket_file);
1.96 dugsong 1036: #endif
1.136 markus 1037: if (auth_sock_name != NULL)
1.1 markus 1038: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1039: auth_sock_name);
1.1 markus 1040:
1041: /* read $HOME/.ssh/environment. */
1.146 markus 1042: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1043: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1044: pw->pw_dir);
1.1 markus 1045: read_environment_file(&env, &envsize, buf);
1046: }
1047: if (debug_flag) {
1048: /* dump the environment */
1049: fprintf(stderr, "Environment:\n");
1050: for (i = 0; env[i]; i++)
1051: fprintf(stderr, " %.200s\n", env[i]);
1052: }
1.127 markus 1053: return env;
1054: }
1055:
1056: /*
1057: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1058: * first in this order).
1059: */
1060: static void
1061: do_rc_files(Session *s, const char *shell)
1062: {
1063: FILE *f = NULL;
1064: char cmd[1024];
1065: int do_xauth;
1066: struct stat st;
1067:
1068: do_xauth =
1069: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1070:
1.231 djm 1071: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1072: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.234 djm 1073: !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1074: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1075: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1076: if (debug_flag)
1077: fprintf(stderr, "Running %s\n", cmd);
1078: f = popen(cmd, "w");
1079: if (f) {
1080: if (do_xauth)
1081: fprintf(f, "%s %s\n", s->auth_proto,
1082: s->auth_data);
1083: pclose(f);
1084: } else
1085: fprintf(stderr, "Could not run %s\n",
1086: _PATH_SSH_USER_RC);
1087: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1088: if (debug_flag)
1089: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1090: _PATH_SSH_SYSTEM_RC);
1091: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1092: if (f) {
1093: if (do_xauth)
1094: fprintf(f, "%s %s\n", s->auth_proto,
1095: s->auth_data);
1096: pclose(f);
1097: } else
1098: fprintf(stderr, "Could not run %s\n",
1099: _PATH_SSH_SYSTEM_RC);
1100: } else if (do_xauth && options.xauth_location != NULL) {
1101: /* Add authority data to .Xauthority if appropriate. */
1102: if (debug_flag) {
1103: fprintf(stderr,
1.151 stevesk 1104: "Running %.500s remove %.100s\n",
1.165 markus 1105: options.xauth_location, s->auth_display);
1.151 stevesk 1106: fprintf(stderr,
1107: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1108: options.xauth_location, s->auth_display,
1109: s->auth_proto, s->auth_data);
1110: }
1111: snprintf(cmd, sizeof cmd, "%s -q -",
1112: options.xauth_location);
1113: f = popen(cmd, "w");
1114: if (f) {
1.151 stevesk 1115: fprintf(f, "remove %s\n",
1116: s->auth_display);
1.127 markus 1117: fprintf(f, "add %s %s %s\n",
1118: s->auth_display, s->auth_proto,
1119: s->auth_data);
1120: pclose(f);
1121: } else {
1122: fprintf(stderr, "Could not run %s\n",
1123: cmd);
1124: }
1125: }
1126: }
1127:
1128: static void
1129: do_nologin(struct passwd *pw)
1130: {
1131: FILE *f = NULL;
1.251 dtucker 1132: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1133: struct stat sb;
1.127 markus 1134:
1.251 dtucker 1135: if (login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1136: return;
1137: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1138:
1139: if (stat(nl, &sb) == -1) {
1140: if (nl != def_nl)
1141: xfree(nl);
1142: return;
1143: }
1144:
1145: /* /etc/nologin exists. Print its contents if we can and exit. */
1146: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1147: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1148: while (fgets(buf, sizeof(buf), f))
1149: fputs(buf, stderr);
1150: fclose(f);
1151: }
1.251 dtucker 1152: exit(254);
1.127 markus 1153: }
1154:
1.226 djm 1155: /*
1156: * Chroot into a directory after checking it for safety: all path components
1157: * must be root-owned directories with strict permissions.
1158: */
1159: static void
1160: safely_chroot(const char *path, uid_t uid)
1161: {
1162: const char *cp;
1163: char component[MAXPATHLEN];
1164: struct stat st;
1165:
1166: if (*path != '/')
1167: fatal("chroot path does not begin at root");
1168: if (strlen(path) >= sizeof(component))
1169: fatal("chroot path too long");
1170:
1171: /*
1172: * Descend the path, checking that each component is a
1173: * root-owned directory with strict permissions.
1174: */
1175: for (cp = path; cp != NULL;) {
1176: if ((cp = strchr(cp, '/')) == NULL)
1177: strlcpy(component, path, sizeof(component));
1178: else {
1179: cp++;
1180: memcpy(component, path, cp - path);
1181: component[cp - path] = '\0';
1182: }
1183:
1184: debug3("%s: checking '%s'", __func__, component);
1185:
1186: if (stat(component, &st) != 0)
1187: fatal("%s: stat(\"%s\"): %s", __func__,
1188: component, strerror(errno));
1189: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1190: fatal("bad ownership or modes for chroot "
1191: "directory %s\"%s\"",
1192: cp == NULL ? "" : "component ", component);
1193: if (!S_ISDIR(st.st_mode))
1194: fatal("chroot path %s\"%s\" is not a directory",
1195: cp == NULL ? "" : "component ", component);
1196:
1197: }
1198:
1199: if (chdir(path) == -1)
1200: fatal("Unable to chdir to chroot path \"%s\": "
1201: "%s", path, strerror(errno));
1202: if (chroot(path) == -1)
1203: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1204: if (chdir("/") == -1)
1205: fatal("%s: chdir(/) after chroot: %s",
1206: __func__, strerror(errno));
1207: verbose("Changed root directory to \"%s\"", path);
1208: }
1209:
1.127 markus 1210: /* Set login name, uid, gid, and groups. */
1.130 provos 1211: void
1.127 markus 1212: do_setusercontext(struct passwd *pw)
1213: {
1.227 djm 1214: char *chroot_path, *tmp;
1215:
1.127 markus 1216: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1217: /* Prepare groups */
1.127 markus 1218: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1219: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1220: perror("unable to set user context");
1221: exit(1);
1222: }
1.226 djm 1223:
1224: if (options.chroot_directory != NULL &&
1225: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1226: tmp = tilde_expand_filename(options.chroot_directory,
1227: pw->pw_uid);
1228: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1229: "u", pw->pw_name, (char *)NULL);
1.226 djm 1230: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1231: free(tmp);
1.226 djm 1232: free(chroot_path);
1233: }
1234:
1235: /* Set UID */
1236: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1237: perror("unable to set user context (setuser)");
1238: exit(1);
1239: }
1.127 markus 1240: }
1241: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1242: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1243: }
1244:
1.131 markus 1245: static void
1.172 markus 1246: do_pwchange(Session *s)
1247: {
1.179 dtucker 1248: fflush(NULL);
1.172 markus 1249: fprintf(stderr, "WARNING: Your password has expired.\n");
1250: if (s->ttyfd != -1) {
1.178 deraadt 1251: fprintf(stderr,
1.172 markus 1252: "You must change your password now and login again!\n");
1253: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1254: perror("passwd");
1255: } else {
1256: fprintf(stderr,
1257: "Password change required but no TTY available.\n");
1258: }
1259: exit(1);
1260: }
1261:
1262: static void
1.130 provos 1263: launch_login(struct passwd *pw, const char *hostname)
1264: {
1265: /* Launch login(1). */
1266:
1267: execl("/usr/bin/login", "login", "-h", hostname,
1268: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1269:
1270: /* Login couldn't be executed, die. */
1271:
1272: perror("login");
1273: exit(1);
1274: }
1275:
1.172 markus 1276: static void
1277: child_close_fds(void)
1278: {
1279: int i;
1280:
1281: if (packet_get_connection_in() == packet_get_connection_out())
1282: close(packet_get_connection_in());
1283: else {
1284: close(packet_get_connection_in());
1285: close(packet_get_connection_out());
1286: }
1287: /*
1288: * Close all descriptors related to channels. They will still remain
1289: * open in the parent.
1290: */
1291: /* XXX better use close-on-exec? -markus */
1292: channel_close_all();
1293:
1294: /*
1295: * Close any extra file descriptors. Note that there may still be
1296: * descriptors left by system functions. They will be closed later.
1297: */
1298: endpwent();
1299:
1300: /*
1.188 djm 1301: * Close any extra open file descriptors so that we don't have them
1.172 markus 1302: * hanging around in clients. Note that we want to do this after
1303: * initgroups, because at least on Solaris 2.3 it leaves file
1304: * descriptors open.
1305: */
1306: for (i = 3; i < 64; i++)
1307: close(i);
1308: }
1309:
1.127 markus 1310: /*
1311: * Performs common processing for the child, such as setting up the
1312: * environment, closing extra file descriptors, setting the user and group
1313: * ids, and executing the command or shell.
1314: */
1.225 markus 1315: #define ARGV_MAX 10
1.127 markus 1316: void
1317: do_child(Session *s, const char *command)
1318: {
1319: extern char **environ;
1320: char **env;
1.225 markus 1321: char *argv[ARGV_MAX];
1.127 markus 1322: const char *shell, *shell0, *hostname = NULL;
1323: struct passwd *pw = s->pw;
1.239 djm 1324: int r = 0;
1.127 markus 1325:
1326: /* remove hostkey from the child's memory */
1327: destroy_sensitive_data();
1328:
1.172 markus 1329: /* Force a password change */
1330: if (s->authctxt->force_pwchange) {
1331: do_setusercontext(pw);
1332: child_close_fds();
1333: do_pwchange(s);
1334: exit(1);
1335: }
1336:
1.127 markus 1337: /* login(1) is only called if we execute the login shell */
1338: if (options.use_login && command != NULL)
1339: options.use_login = 0;
1340:
1341: /*
1342: * Login(1) does this as well, and it needs uid 0 for the "-h"
1343: * switch, so we let login(1) to this for us.
1344: */
1345: if (!options.use_login) {
1346: do_nologin(pw);
1347: do_setusercontext(pw);
1348: }
1349:
1350: /*
1351: * Get the shell from the password data. An empty shell field is
1352: * legal, and means /bin/sh.
1353: */
1354: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1355:
1356: /*
1357: * Make sure $SHELL points to the shell from the password file,
1358: * even if shell is overridden from login.conf
1359: */
1360: env = do_setup_env(s, shell);
1361:
1.127 markus 1362: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1363:
1.26 millert 1364: /* we have to stash the hostname before we close our socket. */
1365: if (options.use_login)
1.70 stevesk 1366: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1367: options.use_dns);
1.1 markus 1368: /*
1369: * Close the connection descriptors; note that this is the child, and
1370: * the server will still have the socket open, and it is important
1371: * that we do not shutdown it. Note that the descriptors cannot be
1372: * closed before building the environment, as we call
1373: * get_remote_ipaddr there.
1374: */
1.172 markus 1375: child_close_fds();
1.1 markus 1376:
1377: /*
1.125 deraadt 1378: * Must take new environment into use so that .ssh/rc,
1379: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1380: */
1381: environ = env;
1.170 jakob 1382:
1383: #ifdef KRB5
1384: /*
1385: * At this point, we check to see if AFS is active and if we have
1386: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1387: * if we can (and need to) extend the ticket into an AFS token. If
1388: * we don't do this, we run into potential problems if the user's
1389: * home directory is in AFS and it's not world-readable.
1390: */
1391:
1392: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1393: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1394: char cell[64];
1395:
1396: debug("Getting AFS token");
1397:
1398: k_setpag();
1399:
1400: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1401: krb5_afslog(s->authctxt->krb5_ctx,
1402: s->authctxt->krb5_fwd_ccache, cell, NULL);
1403:
1404: krb5_afslog_home(s->authctxt->krb5_ctx,
1405: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1406: }
1407: #endif
1.104 markus 1408:
1.188 djm 1409: /* Change current directory to the user's home directory. */
1.104 markus 1410: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1411: /* Suppress missing homedir warning for chroot case */
1412: r = login_getcapbool(lc, "requirehome", 0);
1413: if (r || options.chroot_directory == NULL)
1414: fprintf(stderr, "Could not chdir to home "
1415: "directory %s: %s\n", pw->pw_dir,
1416: strerror(errno));
1417: if (r)
1.104 markus 1418: exit(1);
1419: }
1.230 djm 1420:
1421: closefrom(STDERR_FILENO + 1);
1.1 markus 1422:
1.127 markus 1423: if (!options.use_login)
1424: do_rc_files(s, shell);
1.67 markus 1425:
1426: /* restore SIGPIPE for child */
1.217 stevesk 1427: signal(SIGPIPE, SIG_DFL);
1.67 markus 1428:
1.248 djm 1429: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1430: printf("This service allows sftp connections only.\n");
1431: fflush(NULL);
1432: exit(1);
1433: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1434: extern int optind, optreset;
1435: int i;
1436: char *p, *args;
1437:
1.246 stevesk 1438: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1439: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1440: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1441: if (i < ARGV_MAX - 1)
1442: argv[i++] = p;
1443: argv[i] = NULL;
1444: optind = optreset = 1;
1445: __progname = argv[0];
1.226 djm 1446: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1447: }
1.247 djm 1448:
1449: fflush(NULL);
1.225 markus 1450:
1.127 markus 1451: if (options.use_login) {
1.130 provos 1452: launch_login(pw, hostname);
1453: /* NEVERREACHED */
1.127 markus 1454: }
1455:
1456: /* Get the last component of the shell name. */
1457: if ((shell0 = strrchr(shell, '/')) != NULL)
1458: shell0++;
1459: else
1460: shell0 = shell;
1461:
1.1 markus 1462: /*
1463: * If we have no command, execute the shell. In this case, the shell
1464: * name to be passed in argv[0] is preceded by '-' to indicate that
1465: * this is a login shell.
1466: */
1467: if (!command) {
1.127 markus 1468: char argv0[256];
1.1 markus 1469:
1.127 markus 1470: /* Start the shell. Set initial character to '-'. */
1471: argv0[0] = '-';
1.1 markus 1472:
1.127 markus 1473: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1474: >= sizeof(argv0) - 1) {
1.127 markus 1475: errno = EINVAL;
1.1 markus 1476: perror(shell);
1477: exit(1);
1.127 markus 1478: }
1.1 markus 1479:
1.127 markus 1480: /* Execute the shell. */
1481: argv[0] = argv0;
1482: argv[1] = NULL;
1483: execve(shell, argv, env);
1484:
1485: /* Executing the shell failed. */
1486: perror(shell);
1487: exit(1);
1.1 markus 1488: }
1489: /*
1490: * Execute the command using the user's shell. This uses the -c
1491: * option to execute the command.
1492: */
1.127 markus 1493: argv[0] = (char *) shell0;
1.1 markus 1494: argv[1] = "-c";
1495: argv[2] = (char *) command;
1496: argv[3] = NULL;
1497: execve(shell, argv, env);
1498: perror(shell);
1499: exit(1);
1500: }
1501:
1.237 djm 1502: void
1503: session_unused(int id)
1504: {
1505: debug3("%s: session id %d unused", __func__, id);
1506: if (id >= options.max_sessions ||
1507: id >= sessions_nalloc) {
1508: fatal("%s: insane session id %d (max %d nalloc %d)",
1509: __func__, id, options.max_sessions, sessions_nalloc);
1510: }
1511: bzero(&sessions[id], sizeof(*sessions));
1512: sessions[id].self = id;
1513: sessions[id].used = 0;
1514: sessions[id].chanid = -1;
1515: sessions[id].ptyfd = -1;
1516: sessions[id].ttyfd = -1;
1517: sessions[id].ptymaster = -1;
1518: sessions[id].x11_chanids = NULL;
1519: sessions[id].next_unused = sessions_first_unused;
1520: sessions_first_unused = id;
1521: }
1522:
1.1 markus 1523: Session *
1524: session_new(void)
1525: {
1.237 djm 1526: Session *s, *tmp;
1527:
1528: if (sessions_first_unused == -1) {
1529: if (sessions_nalloc >= options.max_sessions)
1530: return NULL;
1531: debug2("%s: allocate (allocated %d max %d)",
1532: __func__, sessions_nalloc, options.max_sessions);
1533: tmp = xrealloc(sessions, sessions_nalloc + 1,
1534: sizeof(*sessions));
1535: if (tmp == NULL) {
1536: error("%s: cannot allocate %d sessions",
1537: __func__, sessions_nalloc + 1);
1538: return NULL;
1539: }
1540: sessions = tmp;
1541: session_unused(sessions_nalloc++);
1542: }
1543:
1544: if (sessions_first_unused >= sessions_nalloc ||
1545: sessions_first_unused < 0) {
1546: fatal("%s: insane first_unused %d max %d nalloc %d",
1547: __func__, sessions_first_unused, options.max_sessions,
1548: sessions_nalloc);
1549: }
1550:
1551: s = &sessions[sessions_first_unused];
1552: if (s->used) {
1553: fatal("%s: session %d already used",
1554: __func__, sessions_first_unused);
1555: }
1556: sessions_first_unused = s->next_unused;
1557: s->used = 1;
1558: s->next_unused = -1;
1559: debug("session_new: session %d", s->self);
1560:
1561: return s;
1.1 markus 1562: }
1563:
1.94 itojun 1564: static void
1.1 markus 1565: session_dump(void)
1566: {
1567: int i;
1.237 djm 1568: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1569: Session *s = &sessions[i];
1.237 djm 1570:
1571: debug("dump: used %d next_unused %d session %d %p "
1572: "channel %d pid %ld",
1.1 markus 1573: s->used,
1.237 djm 1574: s->next_unused,
1.1 markus 1575: s->self,
1576: s,
1577: s->chanid,
1.137 mpech 1578: (long)s->pid);
1.1 markus 1579: }
1580: }
1581:
1.2 markus 1582: int
1.97 markus 1583: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1584: {
1585: Session *s = session_new();
1586: debug("session_open: channel %d", chanid);
1587: if (s == NULL) {
1588: error("no more sessions");
1589: return 0;
1590: }
1.97 markus 1591: s->authctxt = authctxt;
1592: s->pw = authctxt->pw;
1.167 djm 1593: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1594: fatal("no user for session %d", s->self);
1.2 markus 1595: debug("session_open: session %d: link with channel %d", s->self, chanid);
1596: s->chanid = chanid;
1597: return 1;
1598: }
1599:
1.130 provos 1600: Session *
1601: session_by_tty(char *tty)
1602: {
1603: int i;
1.237 djm 1604: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1605: Session *s = &sessions[i];
1606: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1607: debug("session_by_tty: session %d tty %s", i, tty);
1608: return s;
1609: }
1610: }
1611: debug("session_by_tty: unknown tty %.100s", tty);
1612: session_dump();
1613: return NULL;
1614: }
1615:
1.94 itojun 1616: static Session *
1.2 markus 1617: session_by_channel(int id)
1618: {
1619: int i;
1.237 djm 1620: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1621: Session *s = &sessions[i];
1622: if (s->used && s->chanid == id) {
1.237 djm 1623: debug("session_by_channel: session %d channel %d",
1624: i, id);
1.2 markus 1625: return s;
1626: }
1627: }
1628: debug("session_by_channel: unknown channel %d", id);
1629: session_dump();
1630: return NULL;
1631: }
1632:
1.94 itojun 1633: static Session *
1.184 djm 1634: session_by_x11_channel(int id)
1635: {
1636: int i, j;
1637:
1.237 djm 1638: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1639: Session *s = &sessions[i];
1640:
1641: if (s->x11_chanids == NULL || !s->used)
1642: continue;
1643: for (j = 0; s->x11_chanids[j] != -1; j++) {
1644: if (s->x11_chanids[j] == id) {
1645: debug("session_by_x11_channel: session %d "
1646: "channel %d", s->self, id);
1647: return s;
1648: }
1649: }
1650: }
1651: debug("session_by_x11_channel: unknown channel %d", id);
1652: session_dump();
1653: return NULL;
1654: }
1655:
1656: static Session *
1.2 markus 1657: session_by_pid(pid_t pid)
1658: {
1659: int i;
1.137 mpech 1660: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1661: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1662: Session *s = &sessions[i];
1663: if (s->used && s->pid == pid)
1664: return s;
1665: }
1.137 mpech 1666: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1667: session_dump();
1668: return NULL;
1669: }
1670:
1.94 itojun 1671: static int
1.2 markus 1672: session_window_change_req(Session *s)
1673: {
1674: s->col = packet_get_int();
1675: s->row = packet_get_int();
1676: s->xpixel = packet_get_int();
1677: s->ypixel = packet_get_int();
1.116 markus 1678: packet_check_eom();
1.2 markus 1679: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1680: return 1;
1681: }
1682:
1.94 itojun 1683: static int
1.2 markus 1684: session_pty_req(Session *s)
1685: {
1.45 markus 1686: u_int len;
1.72 stevesk 1687: int n_bytes;
1.132 markus 1688:
1.86 markus 1689: if (no_pty_flag) {
1690: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1691: return 0;
1.86 markus 1692: }
1693: if (s->ttyfd != -1) {
1694: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1695: return 0;
1.86 markus 1696: }
1697:
1.2 markus 1698: s->term = packet_get_string(&len);
1.86 markus 1699:
1700: if (compat20) {
1701: s->col = packet_get_int();
1702: s->row = packet_get_int();
1703: } else {
1704: s->row = packet_get_int();
1705: s->col = packet_get_int();
1706: }
1.2 markus 1707: s->xpixel = packet_get_int();
1708: s->ypixel = packet_get_int();
1709:
1710: if (strcmp(s->term, "") == 0) {
1711: xfree(s->term);
1712: s->term = NULL;
1713: }
1.86 markus 1714:
1.2 markus 1715: /* Allocate a pty and open it. */
1.86 markus 1716: debug("Allocating pty.");
1.237 djm 1717: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1718: sizeof(s->tty)))) {
1.86 markus 1719: if (s->term)
1720: xfree(s->term);
1.2 markus 1721: s->term = NULL;
1722: s->ptyfd = -1;
1723: s->ttyfd = -1;
1724: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1725: return 0;
1.2 markus 1726: }
1727: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1728:
1729: /* for SSH1 the tty modes length is not given */
1730: if (!compat20)
1731: n_bytes = packet_remaining();
1732: tty_parse_modes(s->ttyfd, &n_bytes);
1733:
1.130 provos 1734: if (!use_privsep)
1735: pty_setowner(s->pw, s->tty);
1.86 markus 1736:
1737: /* Set window size from the packet. */
1.2 markus 1738: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1739:
1.116 markus 1740: packet_check_eom();
1.9 markus 1741: session_proctitle(s);
1.2 markus 1742: return 1;
1743: }
1744:
1.94 itojun 1745: static int
1.7 markus 1746: session_subsystem_req(Session *s)
1747: {
1.105 markus 1748: struct stat st;
1.45 markus 1749: u_int len;
1.7 markus 1750: int success = 0;
1.205 djm 1751: char *prog, *cmd, *subsys = packet_get_string(&len);
1.182 djm 1752: u_int i;
1.7 markus 1753:
1.116 markus 1754: packet_check_eom();
1.155 itojun 1755: logit("subsystem request for %.100s", subsys);
1.18 jakob 1756:
1757: for (i = 0; i < options.num_subsystems; i++) {
1.105 markus 1758: if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1759: prog = options.subsystem_command[i];
1760: cmd = options.subsystem_args[i];
1.249 dtucker 1761: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1762: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1763: debug("subsystem: %s", prog);
1.225 markus 1764: } else {
1.249 dtucker 1765: if (stat(prog, &st) < 0)
1766: debug("subsystem: cannot stat %s: %s",
1767: prog, strerror(errno));
1.225 markus 1768: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1769: debug("subsystem: exec() %s", cmd);
1.105 markus 1770: }
1.237 djm 1771: success = do_exec(s, cmd) == 0;
1.122 markus 1772: break;
1.18 jakob 1773: }
1774: }
1775:
1776: if (!success)
1.155 itojun 1777: logit("subsystem request for %.100s failed, subsystem not found",
1.105 markus 1778: subsys);
1.7 markus 1779:
1780: xfree(subsys);
1781: return success;
1782: }
1783:
1.94 itojun 1784: static int
1.7 markus 1785: session_x11_req(Session *s)
1786: {
1.81 markus 1787: int success;
1.7 markus 1788:
1.184 djm 1789: if (s->auth_proto != NULL || s->auth_data != NULL) {
1790: error("session_x11_req: session %d: "
1.190 stevesk 1791: "x11 forwarding already active", s->self);
1.184 djm 1792: return 0;
1793: }
1.7 markus 1794: s->single_connection = packet_get_char();
1795: s->auth_proto = packet_get_string(NULL);
1796: s->auth_data = packet_get_string(NULL);
1797: s->screen = packet_get_int();
1.116 markus 1798: packet_check_eom();
1.7 markus 1799:
1.81 markus 1800: success = session_setup_x11fwd(s);
1801: if (!success) {
1.7 markus 1802: xfree(s->auth_proto);
1803: xfree(s->auth_data);
1.84 markus 1804: s->auth_proto = NULL;
1805: s->auth_data = NULL;
1.7 markus 1806: }
1.81 markus 1807: return success;
1.7 markus 1808: }
1809:
1.94 itojun 1810: static int
1.19 markus 1811: session_shell_req(Session *s)
1812: {
1.116 markus 1813: packet_check_eom();
1.237 djm 1814: return do_exec(s, NULL) == 0;
1.19 markus 1815: }
1816:
1.94 itojun 1817: static int
1.19 markus 1818: session_exec_req(Session *s)
1819: {
1.237 djm 1820: u_int len, success;
1821:
1.19 markus 1822: char *command = packet_get_string(&len);
1.116 markus 1823: packet_check_eom();
1.237 djm 1824: success = do_exec(s, command) == 0;
1.92 markus 1825: xfree(command);
1.237 djm 1826: return success;
1.19 markus 1827: }
1828:
1.94 itojun 1829: static int
1.157 markus 1830: session_break_req(Session *s)
1831: {
1832:
1.175 deraadt 1833: packet_get_int(); /* ignored */
1.157 markus 1834: packet_check_eom();
1835:
1.237 djm 1836: if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
1.157 markus 1837: return 0;
1838: return 1;
1839: }
1840:
1841: static int
1.173 djm 1842: session_env_req(Session *s)
1843: {
1844: char *name, *val;
1845: u_int name_len, val_len, i;
1846:
1847: name = packet_get_string(&name_len);
1848: val = packet_get_string(&val_len);
1849: packet_check_eom();
1850:
1851: /* Don't set too many environment variables */
1852: if (s->num_env > 128) {
1853: debug2("Ignoring env request %s: too many env vars", name);
1854: goto fail;
1855: }
1856:
1857: for (i = 0; i < options.num_accept_env; i++) {
1858: if (match_pattern(name, options.accept_env[i])) {
1859: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.201 djm 1860: s->env = xrealloc(s->env, s->num_env + 1,
1861: sizeof(*s->env));
1.173 djm 1862: s->env[s->num_env].name = name;
1863: s->env[s->num_env].val = val;
1864: s->num_env++;
1865: return (1);
1866: }
1867: }
1868: debug2("Ignoring env request %s: disallowed name", name);
1869:
1870: fail:
1871: xfree(name);
1872: xfree(val);
1873: return (0);
1874: }
1875:
1876: static int
1.43 markus 1877: session_auth_agent_req(Session *s)
1878: {
1879: static int called = 0;
1.116 markus 1880: packet_check_eom();
1.235 pyr 1881: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1882: debug("session_auth_agent_req: no_agent_forwarding_flag");
1883: return 0;
1884: }
1.43 markus 1885: if (called) {
1886: return 0;
1887: } else {
1888: called = 1;
1889: return auth_input_request_forwarding(s->pw);
1890: }
1891: }
1892:
1.123 markus 1893: int
1894: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1895: {
1896: int success = 0;
1897: Session *s;
1898:
1.123 markus 1899: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1900: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1901: c->self, rtype);
1902: return 0;
1903: }
1904: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1905:
1906: /*
1.64 markus 1907: * a session is in LARVAL state until a shell, a command
1908: * or a subsystem is executed
1.2 markus 1909: */
1910: if (c->type == SSH_CHANNEL_LARVAL) {
1911: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1912: success = session_shell_req(s);
1.2 markus 1913: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1914: success = session_exec_req(s);
1.2 markus 1915: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1916: success = session_pty_req(s);
1.7 markus 1917: } else if (strcmp(rtype, "x11-req") == 0) {
1918: success = session_x11_req(s);
1.43 markus 1919: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1920: success = session_auth_agent_req(s);
1.7 markus 1921: } else if (strcmp(rtype, "subsystem") == 0) {
1922: success = session_subsystem_req(s);
1.173 djm 1923: } else if (strcmp(rtype, "env") == 0) {
1924: success = session_env_req(s);
1.2 markus 1925: }
1926: }
1927: if (strcmp(rtype, "window-change") == 0) {
1928: success = session_window_change_req(s);
1.177 djm 1929: } else if (strcmp(rtype, "break") == 0) {
1930: success = session_break_req(s);
1.2 markus 1931: }
1.177 djm 1932:
1.123 markus 1933: return success;
1.2 markus 1934: }
1935:
1936: void
1.241 dtucker 1937: session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
1.2 markus 1938: {
1939: if (!compat20)
1940: fatal("session_set_fds: called for proto != 2.0");
1941: /*
1942: * now that have a child and a pipe to the child,
1943: * we can activate our channel and register the fd's
1944: */
1945: if (s->chanid == -1)
1946: fatal("no channel for session %d", s->self);
1947: channel_set_fds(s->chanid,
1948: fdout, fdin, fderr,
1.42 markus 1949: fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1950: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1951: }
1952:
1.85 markus 1953: /*
1954: * Function to perform pty cleanup. Also called if we get aborted abnormally
1955: * (e.g., due to a dropped connection).
1956: */
1.130 provos 1957: void
1.165 markus 1958: session_pty_cleanup2(Session *s)
1.1 markus 1959: {
1.85 markus 1960: if (s == NULL) {
1961: error("session_pty_cleanup: no session");
1962: return;
1963: }
1964: if (s->ttyfd == -1)
1.1 markus 1965: return;
1966:
1.54 stevesk 1967: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1968:
1969: /* Record that the user has logged out. */
1.85 markus 1970: if (s->pid != 0)
1971: record_logout(s->pid, s->tty);
1.1 markus 1972:
1973: /* Release the pseudo-tty. */
1.130 provos 1974: if (getuid() == 0)
1975: pty_release(s->tty);
1.1 markus 1976:
1977: /*
1978: * Close the server side of the socket pairs. We must do this after
1979: * the pty cleanup, so that another process doesn't get this pty
1980: * while we're still cleaning up.
1981: */
1.237 djm 1982: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
1983: error("close(s->ptymaster/%d): %s",
1984: s->ptymaster, strerror(errno));
1.108 markus 1985:
1986: /* unlink pty from session */
1987: s->ttyfd = -1;
1.2 markus 1988: }
1989:
1.130 provos 1990: void
1.165 markus 1991: session_pty_cleanup(Session *s)
1.130 provos 1992: {
1.165 markus 1993: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 1994: }
1995:
1.147 markus 1996: static char *
1997: sig2name(int sig)
1998: {
1999: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2000: SSH_SIG(ABRT);
2001: SSH_SIG(ALRM);
2002: SSH_SIG(FPE);
2003: SSH_SIG(HUP);
2004: SSH_SIG(ILL);
2005: SSH_SIG(INT);
2006: SSH_SIG(KILL);
2007: SSH_SIG(PIPE);
2008: SSH_SIG(QUIT);
2009: SSH_SIG(SEGV);
2010: SSH_SIG(TERM);
2011: SSH_SIG(USR1);
2012: SSH_SIG(USR2);
2013: #undef SSH_SIG
2014: return "SIG@openssh.com";
2015: }
2016:
1.94 itojun 2017: static void
1.184 djm 2018: session_close_x11(int id)
2019: {
2020: Channel *c;
2021:
1.189 markus 2022: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2023: debug("session_close_x11: x11 channel %d missing", id);
2024: } else {
2025: /* Detach X11 listener */
2026: debug("session_close_x11: detach x11 channel %d", id);
2027: channel_cancel_cleanup(id);
2028: if (c->ostate != CHAN_OUTPUT_CLOSED)
2029: chan_mark_dead(c);
2030: }
2031: }
2032:
2033: static void
2034: session_close_single_x11(int id, void *arg)
2035: {
2036: Session *s;
2037: u_int i;
2038:
2039: debug3("session_close_single_x11: channel %d", id);
2040: channel_cancel_cleanup(id);
1.221 stevesk 2041: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2042: fatal("session_close_single_x11: no x11 channel %d", id);
2043: for (i = 0; s->x11_chanids[i] != -1; i++) {
2044: debug("session_close_single_x11: session %d: "
2045: "closing channel %d", s->self, s->x11_chanids[i]);
2046: /*
2047: * The channel "id" is already closing, but make sure we
2048: * close all of its siblings.
2049: */
2050: if (s->x11_chanids[i] != id)
2051: session_close_x11(s->x11_chanids[i]);
2052: }
2053: xfree(s->x11_chanids);
2054: s->x11_chanids = NULL;
2055: if (s->display) {
2056: xfree(s->display);
2057: s->display = NULL;
2058: }
2059: if (s->auth_proto) {
2060: xfree(s->auth_proto);
2061: s->auth_proto = NULL;
2062: }
2063: if (s->auth_data) {
2064: xfree(s->auth_data);
2065: s->auth_data = NULL;
2066: }
2067: if (s->auth_display) {
2068: xfree(s->auth_display);
2069: s->auth_display = NULL;
2070: }
2071: }
2072:
2073: static void
1.2 markus 2074: session_exit_message(Session *s, int status)
2075: {
2076: Channel *c;
1.124 markus 2077:
2078: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2079: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2080: s->self, s->chanid);
1.137 mpech 2081: debug("session_exit_message: session %d channel %d pid %ld",
2082: s->self, s->chanid, (long)s->pid);
1.2 markus 2083:
2084: if (WIFEXITED(status)) {
1.124 markus 2085: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2086: packet_put_int(WEXITSTATUS(status));
2087: packet_send();
2088: } else if (WIFSIGNALED(status)) {
1.124 markus 2089: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2090: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2091: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2092: packet_put_cstring("");
2093: packet_put_cstring("");
2094: packet_send();
2095: } else {
2096: /* Some weird exit cause. Just exit. */
2097: packet_disconnect("wait returned status %04x.", status);
2098: }
2099:
2100: /* disconnect channel */
2101: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2102:
2103: /*
2104: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2105: * the channel gets EOF. The session will be then be closed
1.187 djm 2106: * by session_close_by_channel when the childs close their fds.
2107: */
2108: channel_register_cleanup(c->self, session_close_by_channel, 1);
2109:
1.5 markus 2110: /*
2111: * emulate a write failure with 'chan_write_failed', nobody will be
2112: * interested in data we write.
2113: * Note that we must not call 'chan_read_failed', since there could
2114: * be some more data waiting in the pipe.
2115: */
1.8 markus 2116: if (c->ostate != CHAN_OUTPUT_CLOSED)
2117: chan_write_failed(c);
1.2 markus 2118: }
2119:
1.130 provos 2120: void
1.85 markus 2121: session_close(Session *s)
1.2 markus 2122: {
1.182 djm 2123: u_int i;
1.173 djm 2124:
1.137 mpech 2125: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165 markus 2126: if (s->ttyfd != -1)
1.85 markus 2127: session_pty_cleanup(s);
1.2 markus 2128: if (s->term)
2129: xfree(s->term);
2130: if (s->display)
2131: xfree(s->display);
1.184 djm 2132: if (s->x11_chanids)
2133: xfree(s->x11_chanids);
1.118 stevesk 2134: if (s->auth_display)
2135: xfree(s->auth_display);
1.2 markus 2136: if (s->auth_data)
2137: xfree(s->auth_data);
2138: if (s->auth_proto)
2139: xfree(s->auth_proto);
1.219 djm 2140: if (s->env != NULL) {
2141: for (i = 0; i < s->num_env; i++) {
2142: xfree(s->env[i].name);
2143: xfree(s->env[i].val);
2144: }
2145: xfree(s->env);
1.173 djm 2146: }
1.9 markus 2147: session_proctitle(s);
1.237 djm 2148: session_unused(s->self);
1.2 markus 2149: }
2150:
2151: void
2152: session_close_by_pid(pid_t pid, int status)
2153: {
2154: Session *s = session_by_pid(pid);
2155: if (s == NULL) {
1.137 mpech 2156: debug("session_close_by_pid: no session for pid %ld",
2157: (long)pid);
1.2 markus 2158: return;
2159: }
2160: if (s->chanid != -1)
2161: session_exit_message(s, status);
1.187 djm 2162: if (s->ttyfd != -1)
2163: session_pty_cleanup(s);
1.197 djm 2164: s->pid = 0;
1.98 markus 2165: }
2166:
1.2 markus 2167: /*
2168: * this is called when a channel dies before
2169: * the session 'child' itself dies
2170: */
2171: void
2172: session_close_by_channel(int id, void *arg)
2173: {
2174: Session *s = session_by_channel(id);
1.187 djm 2175: u_int i;
1.184 djm 2176:
1.2 markus 2177: if (s == NULL) {
1.107 markus 2178: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2179: return;
2180: }
1.137 mpech 2181: debug("session_close_by_channel: channel %d child %ld",
2182: id, (long)s->pid);
1.107 markus 2183: if (s->pid != 0) {
2184: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2185: /*
2186: * delay detach of session, but release pty, since
2187: * the fd's to the child are already closed
2188: */
1.165 markus 2189: if (s->ttyfd != -1)
1.108 markus 2190: session_pty_cleanup(s);
1.107 markus 2191: return;
2192: }
2193: /* detach by removing callback */
1.2 markus 2194: channel_cancel_cleanup(s->chanid);
1.187 djm 2195:
2196: /* Close any X11 listeners associated with this session */
2197: if (s->x11_chanids != NULL) {
2198: for (i = 0; s->x11_chanids[i] != -1; i++) {
2199: session_close_x11(s->x11_chanids[i]);
2200: s->x11_chanids[i] = -1;
2201: }
2202: }
2203:
1.2 markus 2204: s->chanid = -1;
1.106 markus 2205: session_close(s);
2206: }
2207:
2208: void
1.130 provos 2209: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2210: {
2211: int i;
1.237 djm 2212: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2213: Session *s = &sessions[i];
1.130 provos 2214: if (s->used) {
2215: if (closefunc != NULL)
2216: closefunc(s);
2217: else
2218: session_close(s);
2219: }
1.2 markus 2220: }
1.9 markus 2221: }
2222:
1.94 itojun 2223: static char *
1.9 markus 2224: session_tty_list(void)
2225: {
2226: static char buf[1024];
2227: int i;
2228: buf[0] = '\0';
1.237 djm 2229: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2230: Session *s = &sessions[i];
2231: if (s->used && s->ttyfd != -1) {
2232: if (buf[0] != '\0')
2233: strlcat(buf, ",", sizeof buf);
2234: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2235: }
2236: }
2237: if (buf[0] == '\0')
2238: strlcpy(buf, "notty", sizeof buf);
2239: return buf;
2240: }
2241:
2242: void
2243: session_proctitle(Session *s)
2244: {
2245: if (s->pw == NULL)
2246: error("no user for session %d", s->self);
2247: else
2248: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2249: }
2250:
2251: int
2252: session_setup_x11fwd(Session *s)
2253: {
2254: struct stat st;
1.109 stevesk 2255: char display[512], auth_display[512];
2256: char hostname[MAXHOSTNAMELEN];
1.184 djm 2257: u_int i;
1.81 markus 2258:
2259: if (no_x11_forwarding_flag) {
2260: packet_send_debug("X11 forwarding disabled in user configuration file.");
2261: return 0;
2262: }
2263: if (!options.x11_forwarding) {
2264: debug("X11 forwarding disabled in server configuration file.");
2265: return 0;
2266: }
2267: if (!options.xauth_location ||
2268: (stat(options.xauth_location, &st) == -1)) {
2269: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2270: return 0;
2271: }
2272: if (options.use_login) {
2273: packet_send_debug("X11 forwarding disabled; "
2274: "not compatible with UseLogin=yes.");
1.81 markus 2275: return 0;
2276: }
1.87 markus 2277: if (s->display != NULL) {
1.81 markus 2278: debug("X11 display already set.");
2279: return 0;
2280: }
1.140 deraadt 2281: if (x11_create_display_inet(options.x11_display_offset,
2282: options.x11_use_localhost, s->single_connection,
1.184 djm 2283: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2284: debug("x11_create_display_inet failed.");
1.81 markus 2285: return 0;
1.184 djm 2286: }
2287: for (i = 0; s->x11_chanids[i] != -1; i++) {
2288: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2289: session_close_single_x11, 0);
1.81 markus 2290: }
1.109 stevesk 2291:
2292: /* Set up a suitable value for the DISPLAY variable. */
2293: if (gethostname(hostname, sizeof(hostname)) < 0)
2294: fatal("gethostname: %.100s", strerror(errno));
2295: /*
2296: * auth_display must be used as the displayname when the
2297: * authorization entry is added with xauth(1). This will be
2298: * different than the DISPLAY string for localhost displays.
2299: */
1.119 stevesk 2300: if (options.x11_use_localhost) {
1.140 deraadt 2301: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2302: s->display_number, s->screen);
1.140 deraadt 2303: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2304: s->display_number, s->screen);
1.109 stevesk 2305: s->display = xstrdup(display);
1.118 stevesk 2306: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2307: } else {
1.140 deraadt 2308: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2309: s->display_number, s->screen);
2310: s->display = xstrdup(display);
1.118 stevesk 2311: s->auth_display = xstrdup(display);
1.109 stevesk 2312: }
2313:
1.81 markus 2314: return 1;
1.2 markus 2315: }
2316:
1.94 itojun 2317: static void
1.49 markus 2318: do_authenticated2(Authctxt *authctxt)
1.2 markus 2319: {
1.97 markus 2320: server_loop2(authctxt);
1.165 markus 2321: }
2322:
2323: void
2324: do_cleanup(Authctxt *authctxt)
2325: {
2326: static int called = 0;
2327:
2328: debug("do_cleanup");
2329:
2330: /* no cleanup if we're in the child for login shell */
2331: if (is_child)
2332: return;
2333:
2334: /* avoid double cleanup */
2335: if (called)
2336: return;
2337: called = 1;
2338:
1.218 markus 2339: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2340: return;
2341: #ifdef KRB5
2342: if (options.kerberos_ticket_cleanup &&
2343: authctxt->krb5_ctx)
2344: krb5_cleanup_proc(authctxt);
1.161 markus 2345: #endif
1.165 markus 2346:
2347: #ifdef GSSAPI
2348: if (compat20 && options.gss_cleanup_creds)
2349: ssh_gssapi_cleanup_creds();
2350: #endif
2351:
2352: /* remove agent socket */
2353: auth_sock_cleanup_proc(authctxt->pw);
2354:
2355: /*
2356: * Cleanup ptys/utmp only if privsep is disabled,
2357: * or if running in monitor.
2358: */
2359: if (!use_privsep || mm_is_monitor())
2360: session_destroy_all(session_pty_cleanup2);
1.1 markus 2361: }
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