Annotation of src/usr.bin/ssh/session.c, Revision 1.266
1.266 ! markus 1: /* $OpenBSD: session.c,v 1.265 2013/05/17 00:13:14 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"
1.266 ! markus 73: #include "authfd.h"
1.50 markus 74: #include "pathnames.h"
1.51 markus 75: #include "log.h"
76: #include "servconf.h"
1.59 djm 77: #include "sshlogin.h"
1.51 markus 78: #include "serverloop.h"
79: #include "canohost.h"
1.226 djm 80: #include "misc.h"
1.55 itojun 81: #include "session.h"
1.216 deraadt 82: #ifdef GSSAPI
83: #include "ssh-gss.h"
84: #endif
1.130 provos 85: #include "monitor_wrap.h"
1.225 markus 86: #include "sftp.h"
1.171 markus 87:
88: #ifdef KRB5
89: #include <kafs.h>
1.161 markus 90: #endif
91:
1.242 djm 92: #define IS_INTERNAL_SFTP(c) \
93: (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
94: (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
95: c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
96: c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
97:
1.1 markus 98: /* func */
99:
100: Session *session_new(void);
1.256 djm 101: void session_set_fds(Session *, int, int, int, int, int);
1.165 markus 102: void session_pty_cleanup(Session *);
1.94 itojun 103: void session_proctitle(Session *);
104: int session_setup_x11fwd(Session *);
1.237 djm 105: int do_exec_pty(Session *, const char *);
106: int do_exec_no_pty(Session *, const char *);
107: int do_exec(Session *, const char *);
1.94 itojun 108: void do_login(Session *, const char *);
109: void do_child(Session *, const char *);
1.73 djm 110: void do_motd(void);
1.94 itojun 111: int check_quietlogin(Session *, const char *);
1.1 markus 112:
1.94 itojun 113: static void do_authenticated1(Authctxt *);
114: static void do_authenticated2(Authctxt *);
115:
116: static int session_pty_req(Session *);
1.65 markus 117:
1.1 markus 118: /* import */
119: extern ServerOptions options;
120: extern char *__progname;
121: extern int log_stderr;
122: extern int debug_flag;
1.45 markus 123: extern u_int utmp_len;
1.21 markus 124: extern int startup_pipe;
1.74 markus 125: extern void destroy_sensitive_data(void);
1.179 dtucker 126: extern Buffer loginmsg;
1.21 markus 127:
1.34 markus 128: /* original command from peer. */
1.92 markus 129: const char *original_command = NULL;
1.34 markus 130:
1.1 markus 131: /* data */
1.237 djm 132: static int sessions_first_unused = -1;
133: static int sessions_nalloc = 0;
134: static Session *sessions = NULL;
1.1 markus 135:
1.248 djm 136: #define SUBSYSTEM_NONE 0
137: #define SUBSYSTEM_EXT 1
138: #define SUBSYSTEM_INT_SFTP 2
139: #define SUBSYSTEM_INT_SFTP_ERROR 3
1.225 markus 140:
1.129 provos 141: login_cap_t *lc;
1.28 millert 142:
1.165 markus 143: static int is_child = 0;
144:
1.136 markus 145: /* Name and directory of socket for authentication agent forwarding. */
146: static char *auth_sock_name = NULL;
147: static char *auth_sock_dir = NULL;
148:
149: /* removes the agent forwarding socket */
150:
151: static void
1.165 markus 152: auth_sock_cleanup_proc(struct passwd *pw)
1.136 markus 153: {
154: if (auth_sock_name != NULL) {
155: temporarily_use_uid(pw);
156: unlink(auth_sock_name);
157: rmdir(auth_sock_dir);
158: auth_sock_name = NULL;
159: restore_uid();
160: }
161: }
162:
163: static int
164: auth_input_request_forwarding(struct passwd * pw)
165: {
166: Channel *nc;
1.237 djm 167: int sock = -1;
1.136 markus 168: struct sockaddr_un sunaddr;
169:
170: if (auth_sock_name != NULL) {
171: error("authentication forwarding requested twice.");
172: return 0;
173: }
174:
175: /* Temporarily drop privileged uid for mkdir/bind. */
176: temporarily_use_uid(pw);
177:
178: /* Allocate a buffer for the socket name, and format the name. */
1.237 djm 179: auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
1.136 markus 180:
181: /* Create private directory for socket */
182: if (mkdtemp(auth_sock_dir) == NULL) {
183: packet_send_debug("Agent forwarding disabled: "
184: "mkdtemp() failed: %.100s", strerror(errno));
185: restore_uid();
1.265 djm 186: free(auth_sock_dir);
1.136 markus 187: auth_sock_dir = NULL;
1.237 djm 188: goto authsock_err;
1.136 markus 189: }
1.237 djm 190:
191: xasprintf(&auth_sock_name, "%s/agent.%ld",
192: auth_sock_dir, (long) getpid());
1.136 markus 193:
194: /* Create the socket. */
195: sock = socket(AF_UNIX, SOCK_STREAM, 0);
1.237 djm 196: if (sock < 0) {
197: error("socket: %.100s", strerror(errno));
198: restore_uid();
199: goto authsock_err;
200: }
1.136 markus 201:
202: /* Bind it to the name. */
203: memset(&sunaddr, 0, sizeof(sunaddr));
204: sunaddr.sun_family = AF_UNIX;
205: strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
206:
1.237 djm 207: if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
208: error("bind: %.100s", strerror(errno));
209: restore_uid();
210: goto authsock_err;
211: }
1.136 markus 212:
213: /* Restore the privileged uid. */
214: restore_uid();
215:
216: /* Start listening on the socket. */
1.237 djm 217: if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
218: error("listen: %.100s", strerror(errno));
219: goto authsock_err;
220: }
1.136 markus 221:
222: /* Allocate a channel for the authentication agent socket. */
223: nc = channel_new("auth socket",
224: SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
225: CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1.156 markus 226: 0, "auth socket", 1);
1.245 djm 227: nc->path = xstrdup(auth_sock_name);
1.136 markus 228: return 1;
1.237 djm 229:
230: authsock_err:
1.265 djm 231: free(auth_sock_name);
1.237 djm 232: if (auth_sock_dir != NULL) {
233: rmdir(auth_sock_dir);
1.265 djm 234: free(auth_sock_dir);
1.237 djm 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 */
1.261 djm 259: if (no_port_forwarding_flag ||
260: (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
261: channel_disable_adm_local_opens();
262: else
1.65 markus 263: channel_permit_all_opens();
1.252 dtucker 264:
265: auth_debug_send();
1.65 markus 266:
267: if (compat20)
268: do_authenticated2(authctxt);
269: else
270: do_authenticated1(authctxt);
1.79 markus 271:
1.165 markus 272: do_cleanup(authctxt);
1.65 markus 273: }
274:
1.1 markus 275: /*
276: * Prepares for an interactive session. This is called after the user has
277: * been successfully authenticated. During this message exchange, pseudo
278: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
279: * are requested, etc.
280: */
1.94 itojun 281: static void
1.65 markus 282: do_authenticated1(Authctxt *authctxt)
1.1 markus 283: {
284: Session *s;
1.65 markus 285: char *command;
1.117 markus 286: int success, type, screen_flag;
1.139 deraadt 287: int enable_compression_after_reply = 0;
288: u_int proto_len, data_len, dlen, compression_level = 0;
1.1 markus 289:
1.61 markus 290: s = session_new();
1.181 markus 291: if (s == NULL) {
292: error("no more sessions");
293: return;
294: }
1.96 dugsong 295: s->authctxt = authctxt;
1.65 markus 296: s->pw = authctxt->pw;
1.28 millert 297:
1.1 markus 298: /*
299: * We stay in this loop until the client requests to execute a shell
300: * or a command.
301: */
302: for (;;) {
1.65 markus 303: success = 0;
1.1 markus 304:
305: /* Get a packet from the client. */
1.117 markus 306: type = packet_read();
1.1 markus 307:
308: /* Process the packet. */
309: switch (type) {
310: case SSH_CMSG_REQUEST_COMPRESSION:
311: compression_level = packet_get_int();
1.116 markus 312: packet_check_eom();
1.1 markus 313: if (compression_level < 1 || compression_level > 9) {
1.180 markus 314: packet_send_debug("Received invalid compression level %d.",
1.112 deraadt 315: compression_level);
1.138 markus 316: break;
317: }
1.186 markus 318: if (options.compression == COMP_NONE) {
1.138 markus 319: debug2("compression disabled");
1.1 markus 320: break;
321: }
322: /* Enable compression after we have responded with SUCCESS. */
323: enable_compression_after_reply = 1;
324: success = 1;
325: break;
326:
327: case SSH_CMSG_REQUEST_PTY:
1.86 markus 328: success = session_pty_req(s);
1.1 markus 329: break;
330:
331: case SSH_CMSG_X11_REQUEST_FORWARDING:
332: s->auth_proto = packet_get_string(&proto_len);
333: s->auth_data = packet_get_string(&data_len);
334:
1.57 markus 335: screen_flag = packet_get_protocol_flags() &
336: SSH_PROTOFLAG_SCREEN_NUMBER;
337: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
338:
339: if (packet_remaining() == 4) {
340: if (!screen_flag)
341: debug2("Buggy client: "
342: "X11 screen flag missing");
1.1 markus 343: s->screen = packet_get_int();
1.56 markus 344: } else {
1.1 markus 345: s->screen = 0;
1.56 markus 346: }
1.116 markus 347: packet_check_eom();
1.81 markus 348: success = session_setup_x11fwd(s);
349: if (!success) {
1.265 djm 350: free(s->auth_proto);
351: free(s->auth_data);
1.84 markus 352: s->auth_proto = NULL;
353: s->auth_data = NULL;
1.1 markus 354: }
355: break;
356:
357: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1.235 pyr 358: if (!options.allow_agent_forwarding ||
359: no_agent_forwarding_flag || compat13) {
1.1 markus 360: debug("Authentication agent forwarding not permitted for this authentication.");
361: break;
362: }
363: debug("Received authentication agent forwarding request.");
1.65 markus 364: success = auth_input_request_forwarding(s->pw);
1.1 markus 365: break;
366:
367: case SSH_CMSG_PORT_FORWARD_REQUEST:
368: if (no_port_forwarding_flag) {
369: debug("Port forwarding not permitted for this authentication.");
1.39 markus 370: break;
371: }
1.261 djm 372: if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
1.39 markus 373: debug("Port forwarding not permitted.");
1.1 markus 374: break;
375: }
376: debug("Received TCP/IP port forwarding request.");
1.208 markus 377: if (channel_input_port_forward_request(s->pw->pw_uid == 0,
378: options.gateway_ports) < 0) {
379: debug("Port forwarding failed.");
380: break;
381: }
1.1 markus 382: success = 1;
383: break;
384:
385: case SSH_CMSG_MAX_PACKET_SIZE:
386: if (packet_set_maxsize(packet_get_int()) > 0)
387: success = 1;
388: break;
389:
390: case SSH_CMSG_EXEC_SHELL:
391: case SSH_CMSG_EXEC_CMD:
392: if (type == SSH_CMSG_EXEC_CMD) {
393: command = packet_get_string(&dlen);
394: debug("Exec command '%.500s'", command);
1.237 djm 395: if (do_exec(s, command) != 0)
396: packet_disconnect(
397: "command execution failed");
1.265 djm 398: free(command);
1.1 markus 399: } else {
1.237 djm 400: if (do_exec(s, NULL) != 0)
401: packet_disconnect(
402: "shell execution failed");
1.1 markus 403: }
1.116 markus 404: packet_check_eom();
1.82 markus 405: session_close(s);
1.1 markus 406: return;
407:
408: default:
409: /*
410: * Any unknown messages in this phase are ignored,
411: * and a failure message is returned.
412: */
1.155 itojun 413: logit("Unknown packet type received after authentication: %d", type);
1.1 markus 414: }
415: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
416: packet_send();
417: packet_write_wait();
418:
419: /* Enable compression now that we have replied if appropriate. */
420: if (enable_compression_after_reply) {
421: enable_compression_after_reply = 0;
422: packet_start_compression(compression_level);
423: }
424: }
425: }
426:
1.238 markus 427: #define USE_PIPES
1.1 markus 428: /*
429: * This is called to fork and execute a command when we have no tty. This
430: * will call do_child from the child, and server_loop from the parent after
431: * setting up file descriptors and such.
432: */
1.237 djm 433: int
1.63 markus 434: do_exec_no_pty(Session *s, const char *command)
1.1 markus 435: {
1.137 mpech 436: pid_t pid;
1.238 markus 437: #ifdef USE_PIPES
438: int pin[2], pout[2], perr[2];
439:
1.253 djm 440: if (s == NULL)
441: fatal("do_exec_no_pty: no session");
442:
1.238 markus 443: /* Allocate pipes for communicating with the program. */
444: if (pipe(pin) < 0) {
445: error("%s: pipe in: %.100s", __func__, strerror(errno));
446: return -1;
447: }
448: if (pipe(pout) < 0) {
449: error("%s: pipe out: %.100s", __func__, strerror(errno));
450: close(pin[0]);
451: close(pin[1]);
452: return -1;
453: }
1.256 djm 454: if (pipe(perr) < 0) {
455: error("%s: pipe err: %.100s", __func__,
456: strerror(errno));
457: close(pin[0]);
458: close(pin[1]);
459: close(pout[0]);
460: close(pout[1]);
461: return -1;
1.238 markus 462: }
463: #else
1.237 djm 464: int inout[2], err[2];
1.1 markus 465:
1.253 djm 466: if (s == NULL)
467: fatal("do_exec_no_pty: no session");
468:
1.1 markus 469: /* Uses socket pairs to communicate with the program. */
1.237 djm 470: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
471: error("%s: socketpair #1: %.100s", __func__, strerror(errno));
472: return -1;
473: }
1.256 djm 474: if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
475: error("%s: socketpair #2: %.100s", __func__,
476: strerror(errno));
477: close(inout[0]);
478: close(inout[1]);
479: return -1;
1.237 djm 480: }
1.238 markus 481: #endif
1.237 djm 482:
1.9 markus 483: session_proctitle(s);
1.1 markus 484:
485: /* Fork the child. */
1.237 djm 486: switch ((pid = fork())) {
487: case -1:
488: error("%s: fork: %.100s", __func__, strerror(errno));
1.238 markus 489: #ifdef USE_PIPES
490: close(pin[0]);
491: close(pin[1]);
492: close(pout[0]);
493: close(pout[1]);
1.256 djm 494: close(perr[0]);
1.238 markus 495: close(perr[1]);
496: #else
1.237 djm 497: close(inout[0]);
498: close(inout[1]);
499: close(err[0]);
1.256 djm 500: close(err[1]);
1.238 markus 501: #endif
1.237 djm 502: return -1;
503: case 0:
1.165 markus 504: is_child = 1;
1.144 markus 505:
1.1 markus 506: /* Child. Reinitialize the log since the pid has changed. */
1.237 djm 507: log_init(__progname, options.log_level,
508: options.log_facility, log_stderr);
1.1 markus 509:
510: /*
511: * Create a new session and process group since the 4.4BSD
512: * setlogin() affects the entire process group.
513: */
514: if (setsid() < 0)
515: error("setsid failed: %.100s", strerror(errno));
516:
1.238 markus 517: #ifdef USE_PIPES
518: /*
519: * Redirect stdin. We close the parent side of the socket
520: * pair, and make the child side the standard input.
521: */
522: close(pin[1]);
523: if (dup2(pin[0], 0) < 0)
524: perror("dup2 stdin");
525: close(pin[0]);
526:
527: /* Redirect stdout. */
528: close(pout[0]);
529: if (dup2(pout[1], 1) < 0)
530: perror("dup2 stdout");
531: close(pout[1]);
532:
533: /* Redirect stderr. */
1.256 djm 534: close(perr[0]);
1.238 markus 535: if (dup2(perr[1], 2) < 0)
536: perror("dup2 stderr");
537: close(perr[1]);
538: #else
1.1 markus 539: /*
540: * Redirect stdin, stdout, and stderr. Stdin and stdout will
541: * use the same socket, as some programs (particularly rdist)
542: * seem to depend on it.
543: */
544: close(inout[1]);
1.256 djm 545: close(err[1]);
1.1 markus 546: if (dup2(inout[0], 0) < 0) /* stdin */
547: perror("dup2 stdin");
1.237 djm 548: if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
1.1 markus 549: perror("dup2 stdout");
1.238 markus 550: close(inout[0]);
1.1 markus 551: if (dup2(err[0], 2) < 0) /* stderr */
552: perror("dup2 stderr");
1.238 markus 553: close(err[0]);
554: #endif
1.1 markus 555:
556: /* Do processing for the child (exec command etc). */
1.60 markus 557: do_child(s, command);
1.1 markus 558: /* NOTREACHED */
1.237 djm 559: default:
560: break;
1.1 markus 561: }
1.237 djm 562:
1.1 markus 563: s->pid = pid;
1.47 markus 564: /* Set interactive/non-interactive mode. */
1.257 djm 565: packet_set_interactive(s->display != NULL,
566: options.ip_qos_interactive, options.ip_qos_bulk);
1.1 markus 567:
1.238 markus 568: #ifdef USE_PIPES
569: /* We are the parent. Close the child sides of the pipes. */
570: close(pin[0]);
571: close(pout[1]);
572: close(perr[1]);
573:
574: if (compat20) {
1.256 djm 575: session_set_fds(s, pin[1], pout[0], perr[0],
576: s->is_subsystem, 0);
1.238 markus 577: } else {
578: /* Enter the interactive session. */
579: server_loop(pid, pin[1], pout[0], perr[0]);
580: /* server_loop has closed pin[1], pout[0], and perr[0]. */
581: }
582: #else
1.1 markus 583: /* We are the parent. Close the child sides of the socket pairs. */
584: close(inout[0]);
585: close(err[0]);
586:
587: /*
588: * Enter the interactive session. Note: server_loop must be able to
589: * handle the case that fdin and fdout are the same.
590: */
1.2 markus 591: if (compat20) {
1.256 djm 592: session_set_fds(s, inout[1], inout[1], err[1],
593: s->is_subsystem, 0);
1.2 markus 594: } else {
595: server_loop(pid, inout[1], inout[1], err[1]);
596: /* server_loop has closed inout[1] and err[1]. */
597: }
1.238 markus 598: #endif
1.237 djm 599: return 0;
1.1 markus 600: }
601:
602: /*
603: * This is called to fork and execute a command when we have a tty. This
604: * will call do_child from the child, and server_loop from the parent after
605: * setting up file descriptors, controlling tty, updating wtmp, utmp,
606: * lastlog, and other such operations.
607: */
1.237 djm 608: int
1.63 markus 609: do_exec_pty(Session *s, const char *command)
1.1 markus 610: {
611: int fdout, ptyfd, ttyfd, ptymaster;
612: pid_t pid;
613:
614: if (s == NULL)
615: fatal("do_exec_pty: no session");
616: ptyfd = s->ptyfd;
617: ttyfd = s->ttyfd;
618:
1.237 djm 619: /*
620: * Create another descriptor of the pty master side for use as the
621: * standard input. We could use the original descriptor, but this
622: * simplifies code in server_loop. The descriptor is bidirectional.
623: * Do this before forking (and cleanup in the child) so as to
624: * detect and gracefully fail out-of-fd conditions.
625: */
626: if ((fdout = dup(ptyfd)) < 0) {
627: error("%s: dup #1: %s", __func__, strerror(errno));
628: close(ttyfd);
629: close(ptyfd);
630: return -1;
631: }
632: /* we keep a reference to the pty master */
633: if ((ptymaster = dup(ptyfd)) < 0) {
634: error("%s: dup #2: %s", __func__, strerror(errno));
635: close(ttyfd);
636: close(ptyfd);
637: close(fdout);
638: return -1;
639: }
640:
1.1 markus 641: /* Fork the child. */
1.237 djm 642: switch ((pid = fork())) {
643: case -1:
644: error("%s: fork: %.100s", __func__, strerror(errno));
645: close(fdout);
646: close(ptymaster);
647: close(ttyfd);
648: close(ptyfd);
649: return -1;
650: case 0:
1.165 markus 651: is_child = 1;
1.97 markus 652:
1.237 djm 653: close(fdout);
654: close(ptymaster);
655:
1.24 markus 656: /* Child. Reinitialize the log because the pid has changed. */
1.237 djm 657: log_init(__progname, options.log_level,
658: options.log_facility, log_stderr);
1.1 markus 659: /* Close the master side of the pseudo tty. */
660: close(ptyfd);
661:
662: /* Make the pseudo tty our controlling tty. */
663: pty_make_controlling_tty(&ttyfd, s->tty);
664:
1.103 markus 665: /* Redirect stdin/stdout/stderr from the pseudo tty. */
666: if (dup2(ttyfd, 0) < 0)
667: error("dup2 stdin: %s", strerror(errno));
668: if (dup2(ttyfd, 1) < 0)
669: error("dup2 stdout: %s", strerror(errno));
670: if (dup2(ttyfd, 2) < 0)
671: error("dup2 stderr: %s", strerror(errno));
1.1 markus 672:
673: /* Close the extra descriptor for the pseudo tty. */
674: close(ttyfd);
675:
1.24 markus 676: /* record login, etc. similar to login(1) */
1.41 markus 677: if (!(options.use_login && command == NULL))
678: do_login(s, command);
1.228 djm 679:
1.237 djm 680: /*
681: * Do common processing for the child, such as execing
682: * the command.
683: */
1.60 markus 684: do_child(s, command);
1.1 markus 685: /* NOTREACHED */
1.237 djm 686: default:
687: break;
1.1 markus 688: }
689: s->pid = pid;
690:
691: /* Parent. Close the slave side of the pseudo tty. */
692: close(ttyfd);
693:
1.237 djm 694: /* Enter interactive session. */
1.1 markus 695: s->ptymaster = ptymaster;
1.257 djm 696: packet_set_interactive(1,
697: options.ip_qos_interactive, options.ip_qos_bulk);
1.2 markus 698: if (compat20) {
1.256 djm 699: session_set_fds(s, ptyfd, fdout, -1, 1, 1);
1.2 markus 700: } else {
701: server_loop(pid, ptyfd, fdout, -1);
702: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 703: }
1.237 djm 704: return 0;
1.24 markus 705: }
706:
1.90 markus 707: /*
708: * This is called to fork and execute a command. If another command is
709: * to be forced, execute that instead.
710: */
1.237 djm 711: int
1.90 markus 712: do_exec(Session *s, const char *command)
713: {
1.237 djm 714: int ret;
715:
1.210 dtucker 716: if (options.adm_forced_command) {
717: original_command = command;
718: command = options.adm_forced_command;
1.248 djm 719: if (IS_INTERNAL_SFTP(command)) {
720: s->is_subsystem = s->is_subsystem ?
721: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
722: } else if (s->is_subsystem)
1.225 markus 723: s->is_subsystem = SUBSYSTEM_EXT;
1.210 dtucker 724: debug("Forced command (config) '%.900s'", command);
725: } else if (forced_command) {
1.90 markus 726: original_command = command;
727: command = forced_command;
1.248 djm 728: if (IS_INTERNAL_SFTP(command)) {
729: s->is_subsystem = s->is_subsystem ?
730: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
731: } else if (s->is_subsystem)
1.225 markus 732: s->is_subsystem = SUBSYSTEM_EXT;
1.210 dtucker 733: debug("Forced command (key option) '%.900s'", command);
1.90 markus 734: }
1.163 markus 735:
736: #ifdef GSSAPI
737: if (options.gss_authentication) {
738: temporarily_use_uid(s->pw);
739: ssh_gssapi_storecreds();
740: restore_uid();
741: }
742: #endif
1.90 markus 743: if (s->ttyfd != -1)
1.237 djm 744: ret = do_exec_pty(s, command);
1.90 markus 745: else
1.237 djm 746: ret = do_exec_no_pty(s, command);
1.90 markus 747:
1.92 markus 748: original_command = NULL;
1.179 dtucker 749:
750: /*
751: * Clear loginmsg: it's the child's responsibility to display
752: * it to the user, otherwise multiple sessions may accumulate
753: * multiple copies of the login messages.
754: */
755: buffer_clear(&loginmsg);
1.237 djm 756:
757: return ret;
1.90 markus 758: }
759:
760:
1.24 markus 761: /* administrative, login(1)-like work */
762: void
1.41 markus 763: do_login(Session *s, const char *command)
1.24 markus 764: {
765: socklen_t fromlen;
766: struct sockaddr_storage from;
767: struct passwd * pw = s->pw;
768: pid_t pid = getpid();
769:
770: /*
771: * Get IP address of client. If the connection is not a socket, let
772: * the address be 0.0.0.0.
773: */
774: memset(&from, 0, sizeof(from));
1.148 stevesk 775: fromlen = sizeof(from);
1.24 markus 776: if (packet_connection_is_on_socket()) {
777: if (getpeername(packet_get_connection_in(),
1.200 deraadt 778: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 779: debug("getpeername: %.100s", strerror(errno));
1.165 markus 780: cleanup_exit(255);
1.24 markus 781: }
782: }
1.25 markus 783:
1.24 markus 784: /* Record that there was a login on that tty from the remote host. */
1.133 markus 785: if (!use_privsep)
786: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
787: get_remote_name_or_ip(utmp_len,
1.158 markus 788: options.use_dns),
1.148 stevesk 789: (struct sockaddr *)&from, fromlen);
1.24 markus 790:
1.73 djm 791: if (check_quietlogin(s, command))
1.24 markus 792: return;
1.73 djm 793:
1.179 dtucker 794: display_loginmsg();
1.73 djm 795:
796: do_motd();
797: }
798:
799: /*
800: * Display the message of the day.
801: */
802: void
803: do_motd(void)
804: {
805: FILE *f;
806: char buf[256];
807:
1.24 markus 808: if (options.print_motd) {
1.28 millert 809: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
810: "/etc/motd"), "r");
1.24 markus 811: if (f) {
812: while (fgets(buf, sizeof(buf), f))
813: fputs(buf, stdout);
814: fclose(f);
815: }
1.2 markus 816: }
1.73 djm 817: }
818:
819:
820: /*
821: * Check for quiet login, either .hushlogin or command given.
822: */
823: int
824: check_quietlogin(Session *s, const char *command)
825: {
826: char buf[256];
1.96 dugsong 827: struct passwd *pw = s->pw;
1.73 djm 828: struct stat st;
829:
830: /* Return 1 if .hushlogin exists or a command given. */
831: if (command != NULL)
832: return 1;
833: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
834: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
835: return 1;
836: return 0;
1.1 markus 837: }
838:
839: /*
840: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 841: * already exists, its value is overridden.
1.1 markus 842: */
1.161 markus 843: void
1.45 markus 844: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 845: const char *value)
1.1 markus 846: {
1.164 markus 847: char **env;
848: u_int envsize;
1.45 markus 849: u_int i, namelen;
1.1 markus 850:
851: /*
852: * Find the slot where the value should be stored. If the variable
853: * already exists, we reuse the slot; otherwise we append a new slot
854: * at the end of the array, expanding if necessary.
855: */
856: env = *envp;
857: namelen = strlen(name);
858: for (i = 0; env[i]; i++)
859: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
860: break;
861: if (env[i]) {
862: /* Reuse the slot. */
1.265 djm 863: free(env[i]);
1.1 markus 864: } else {
865: /* New variable. Expand if necessary. */
1.164 markus 866: envsize = *envsizep;
867: if (i >= envsize - 1) {
868: if (envsize >= 1000)
869: fatal("child_set_env: too many env vars");
870: envsize += 50;
1.201 djm 871: env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1.164 markus 872: *envsizep = envsize;
1.1 markus 873: }
874: /* Need to set the NULL pointer at end of array beyond the new slot. */
875: env[i + 1] = NULL;
876: }
877:
878: /* Allocate space and format the variable in the appropriate slot. */
879: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
880: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
881: }
882:
883: /*
884: * Reads environment variables from the given file and adds/overrides them
885: * into the environment. If the file does not exist, this does nothing.
886: * Otherwise, it must consist of empty lines, comments (line starts with '#')
887: * and assignments of the form name=value. No other forms are allowed.
888: */
1.94 itojun 889: static void
1.45 markus 890: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 891: const char *filename)
1.1 markus 892: {
893: FILE *f;
894: char buf[4096];
895: char *cp, *value;
1.142 deraadt 896: u_int lineno = 0;
1.1 markus 897:
898: f = fopen(filename, "r");
899: if (!f)
900: return;
901:
902: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 903: if (++lineno > 1000)
904: fatal("Too many lines in environment file %s", filename);
1.1 markus 905: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
906: ;
907: if (!*cp || *cp == '#' || *cp == '\n')
908: continue;
1.224 gilles 909:
910: cp[strcspn(cp, "\n")] = '\0';
911:
1.1 markus 912: value = strchr(cp, '=');
913: if (value == NULL) {
1.142 deraadt 914: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
915: filename);
1.1 markus 916: continue;
917: }
1.14 deraadt 918: /*
919: * Replace the equals sign by nul, and advance value to
920: * the value string.
921: */
1.1 markus 922: *value = '\0';
923: value++;
924: child_set_env(env, envsize, cp, value);
925: }
926: fclose(f);
927: }
928:
1.127 markus 929: static char **
930: do_setup_env(Session *s, const char *shell)
1.1 markus 931: {
932: char buf[256];
1.127 markus 933: u_int i, envsize;
1.154 markus 934: char **env, *laddr;
1.127 markus 935: struct passwd *pw = s->pw;
1.1 markus 936:
937: /* Initialize the environment. */
938: envsize = 100;
1.220 djm 939: env = xcalloc(envsize, sizeof(char *));
1.1 markus 940: env[0] = NULL;
941:
1.161 markus 942: #ifdef GSSAPI
1.168 djm 943: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 944: * the childs environment as they see fit
945: */
946: ssh_gssapi_do_child(&env, &envsize);
947: #endif
948:
1.1 markus 949: if (!options.use_login) {
950: /* Set basic environment. */
1.173 djm 951: for (i = 0; i < s->num_env; i++)
1.178 deraadt 952: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 953: s->env[i].val);
954:
1.1 markus 955: child_set_env(&env, &envsize, "USER", pw->pw_name);
956: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
957: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 958: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
959: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
960: else
961: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 962:
963: snprintf(buf, sizeof buf, "%.200s/%.50s",
964: _PATH_MAILDIR, pw->pw_name);
965: child_set_env(&env, &envsize, "MAIL", buf);
966:
967: /* Normal systems set SHELL by default. */
968: child_set_env(&env, &envsize, "SHELL", shell);
969: }
970: if (getenv("TZ"))
971: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
972:
973: /* Set custom environment options from RSA authentication. */
1.110 markus 974: if (!options.use_login) {
975: while (custom_environment) {
976: struct envstring *ce = custom_environment;
1.143 deraadt 977: char *str = ce->s;
1.127 markus 978:
1.143 deraadt 979: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 980: ;
1.143 deraadt 981: if (str[i] == '=') {
982: str[i] = 0;
983: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 984: }
985: custom_environment = ce->next;
1.265 djm 986: free(ce->s);
987: free(ce);
1.1 markus 988: }
989: }
990:
1.149 stevesk 991: /* SSH_CLIENT deprecated */
1.1 markus 992: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 993: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 994: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 995:
1.154 markus 996: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 997: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 998: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1.265 djm 999: free(laddr);
1.149 stevesk 1000: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1001:
1.60 markus 1002: if (s->ttyfd != -1)
1003: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1004: if (s->term)
1005: child_set_env(&env, &envsize, "TERM", s->term);
1006: if (s->display)
1007: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1008: if (original_command)
1009: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1010: original_command);
1.96 dugsong 1011: #ifdef KRB5
1012: if (s->authctxt->krb5_ticket_file)
1013: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1014: s->authctxt->krb5_ticket_file);
1.96 dugsong 1015: #endif
1.136 markus 1016: if (auth_sock_name != NULL)
1.1 markus 1017: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1018: auth_sock_name);
1.1 markus 1019:
1020: /* read $HOME/.ssh/environment. */
1.146 markus 1021: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1022: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1023: pw->pw_dir);
1.1 markus 1024: read_environment_file(&env, &envsize, buf);
1025: }
1026: if (debug_flag) {
1027: /* dump the environment */
1028: fprintf(stderr, "Environment:\n");
1029: for (i = 0; env[i]; i++)
1030: fprintf(stderr, " %.200s\n", env[i]);
1031: }
1.127 markus 1032: return env;
1033: }
1034:
1035: /*
1036: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1037: * first in this order).
1038: */
1039: static void
1040: do_rc_files(Session *s, const char *shell)
1041: {
1042: FILE *f = NULL;
1043: char cmd[1024];
1044: int do_xauth;
1045: struct stat st;
1046:
1047: do_xauth =
1048: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1049:
1.231 djm 1050: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1051: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.234 djm 1052: !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1053: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1054: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1055: if (debug_flag)
1056: fprintf(stderr, "Running %s\n", cmd);
1057: f = popen(cmd, "w");
1058: if (f) {
1059: if (do_xauth)
1060: fprintf(f, "%s %s\n", s->auth_proto,
1061: s->auth_data);
1062: pclose(f);
1063: } else
1064: fprintf(stderr, "Could not run %s\n",
1065: _PATH_SSH_USER_RC);
1066: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1067: if (debug_flag)
1068: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1069: _PATH_SSH_SYSTEM_RC);
1070: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1071: if (f) {
1072: if (do_xauth)
1073: fprintf(f, "%s %s\n", s->auth_proto,
1074: s->auth_data);
1075: pclose(f);
1076: } else
1077: fprintf(stderr, "Could not run %s\n",
1078: _PATH_SSH_SYSTEM_RC);
1079: } else if (do_xauth && options.xauth_location != NULL) {
1080: /* Add authority data to .Xauthority if appropriate. */
1081: if (debug_flag) {
1082: fprintf(stderr,
1.151 stevesk 1083: "Running %.500s remove %.100s\n",
1.165 markus 1084: options.xauth_location, s->auth_display);
1.151 stevesk 1085: fprintf(stderr,
1086: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1087: options.xauth_location, s->auth_display,
1088: s->auth_proto, s->auth_data);
1089: }
1090: snprintf(cmd, sizeof cmd, "%s -q -",
1091: options.xauth_location);
1092: f = popen(cmd, "w");
1093: if (f) {
1.151 stevesk 1094: fprintf(f, "remove %s\n",
1095: s->auth_display);
1.127 markus 1096: fprintf(f, "add %s %s %s\n",
1097: s->auth_display, s->auth_proto,
1098: s->auth_data);
1099: pclose(f);
1100: } else {
1101: fprintf(stderr, "Could not run %s\n",
1102: cmd);
1103: }
1104: }
1105: }
1106:
1107: static void
1108: do_nologin(struct passwd *pw)
1109: {
1110: FILE *f = NULL;
1.251 dtucker 1111: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1112: struct stat sb;
1.127 markus 1113:
1.260 guenther 1114: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1115: return;
1116: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1117:
1118: if (stat(nl, &sb) == -1) {
1119: if (nl != def_nl)
1.265 djm 1120: free(nl);
1.251 dtucker 1121: return;
1122: }
1123:
1124: /* /etc/nologin exists. Print its contents if we can and exit. */
1125: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1126: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1127: while (fgets(buf, sizeof(buf), f))
1128: fputs(buf, stderr);
1129: fclose(f);
1130: }
1.251 dtucker 1131: exit(254);
1.127 markus 1132: }
1133:
1.226 djm 1134: /*
1135: * Chroot into a directory after checking it for safety: all path components
1136: * must be root-owned directories with strict permissions.
1137: */
1138: static void
1139: safely_chroot(const char *path, uid_t uid)
1140: {
1141: const char *cp;
1142: char component[MAXPATHLEN];
1143: struct stat st;
1144:
1145: if (*path != '/')
1146: fatal("chroot path does not begin at root");
1147: if (strlen(path) >= sizeof(component))
1148: fatal("chroot path too long");
1149:
1150: /*
1151: * Descend the path, checking that each component is a
1152: * root-owned directory with strict permissions.
1153: */
1154: for (cp = path; cp != NULL;) {
1155: if ((cp = strchr(cp, '/')) == NULL)
1156: strlcpy(component, path, sizeof(component));
1157: else {
1158: cp++;
1159: memcpy(component, path, cp - path);
1160: component[cp - path] = '\0';
1161: }
1162:
1163: debug3("%s: checking '%s'", __func__, component);
1164:
1165: if (stat(component, &st) != 0)
1166: fatal("%s: stat(\"%s\"): %s", __func__,
1167: component, strerror(errno));
1168: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1169: fatal("bad ownership or modes for chroot "
1170: "directory %s\"%s\"",
1171: cp == NULL ? "" : "component ", component);
1172: if (!S_ISDIR(st.st_mode))
1173: fatal("chroot path %s\"%s\" is not a directory",
1174: cp == NULL ? "" : "component ", component);
1175:
1176: }
1177:
1178: if (chdir(path) == -1)
1179: fatal("Unable to chdir to chroot path \"%s\": "
1180: "%s", path, strerror(errno));
1181: if (chroot(path) == -1)
1182: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1183: if (chdir("/") == -1)
1184: fatal("%s: chdir(/) after chroot: %s",
1185: __func__, strerror(errno));
1186: verbose("Changed root directory to \"%s\"", path);
1187: }
1188:
1.127 markus 1189: /* Set login name, uid, gid, and groups. */
1.130 provos 1190: void
1.127 markus 1191: do_setusercontext(struct passwd *pw)
1192: {
1.227 djm 1193: char *chroot_path, *tmp;
1194:
1.127 markus 1195: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1196: /* Prepare groups */
1.127 markus 1197: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1198: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1199: perror("unable to set user context");
1200: exit(1);
1201: }
1.226 djm 1202:
1203: if (options.chroot_directory != NULL &&
1204: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1205: tmp = tilde_expand_filename(options.chroot_directory,
1206: pw->pw_uid);
1207: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1208: "u", pw->pw_name, (char *)NULL);
1.226 djm 1209: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1210: free(tmp);
1.226 djm 1211: free(chroot_path);
1.264 djm 1212: /* Make sure we don't attempt to chroot again */
1213: free(options.chroot_directory);
1214: options.chroot_directory = NULL;
1.226 djm 1215: }
1216:
1217: /* Set UID */
1218: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1219: perror("unable to set user context (setuser)");
1220: exit(1);
1221: }
1.264 djm 1222: } else if (options.chroot_directory != NULL &&
1223: strcasecmp(options.chroot_directory, "none") != 0) {
1224: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1225: }
1.264 djm 1226:
1.127 markus 1227: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1228: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1229: }
1230:
1.131 markus 1231: static void
1.172 markus 1232: do_pwchange(Session *s)
1233: {
1.179 dtucker 1234: fflush(NULL);
1.172 markus 1235: fprintf(stderr, "WARNING: Your password has expired.\n");
1236: if (s->ttyfd != -1) {
1.178 deraadt 1237: fprintf(stderr,
1.172 markus 1238: "You must change your password now and login again!\n");
1239: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1240: perror("passwd");
1241: } else {
1242: fprintf(stderr,
1243: "Password change required but no TTY available.\n");
1244: }
1245: exit(1);
1246: }
1247:
1248: static void
1.130 provos 1249: launch_login(struct passwd *pw, const char *hostname)
1250: {
1251: /* Launch login(1). */
1252:
1253: execl("/usr/bin/login", "login", "-h", hostname,
1254: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1255:
1256: /* Login couldn't be executed, die. */
1257:
1258: perror("login");
1259: exit(1);
1260: }
1261:
1.172 markus 1262: static void
1263: child_close_fds(void)
1264: {
1.266 ! markus 1265: extern AuthenticationConnection *auth_conn;
! 1266:
! 1267: if (auth_conn) {
! 1268: ssh_close_authentication_connection(auth_conn);
! 1269: auth_conn = NULL;
! 1270: }
! 1271:
1.172 markus 1272: if (packet_get_connection_in() == packet_get_connection_out())
1273: close(packet_get_connection_in());
1274: else {
1275: close(packet_get_connection_in());
1276: close(packet_get_connection_out());
1277: }
1278: /*
1279: * Close all descriptors related to channels. They will still remain
1280: * open in the parent.
1281: */
1282: /* XXX better use close-on-exec? -markus */
1283: channel_close_all();
1284:
1285: /*
1286: * Close any extra file descriptors. Note that there may still be
1287: * descriptors left by system functions. They will be closed later.
1288: */
1289: endpwent();
1290:
1291: /*
1.188 djm 1292: * Close any extra open file descriptors so that we don't have them
1.172 markus 1293: * hanging around in clients. Note that we want to do this after
1294: * initgroups, because at least on Solaris 2.3 it leaves file
1295: * descriptors open.
1296: */
1.258 djm 1297: closefrom(STDERR_FILENO + 1);
1.172 markus 1298: }
1299:
1.127 markus 1300: /*
1301: * Performs common processing for the child, such as setting up the
1302: * environment, closing extra file descriptors, setting the user and group
1303: * ids, and executing the command or shell.
1304: */
1.225 markus 1305: #define ARGV_MAX 10
1.127 markus 1306: void
1307: do_child(Session *s, const char *command)
1308: {
1309: extern char **environ;
1310: char **env;
1.225 markus 1311: char *argv[ARGV_MAX];
1.127 markus 1312: const char *shell, *shell0, *hostname = NULL;
1313: struct passwd *pw = s->pw;
1.239 djm 1314: int r = 0;
1.127 markus 1315:
1316: /* remove hostkey from the child's memory */
1317: destroy_sensitive_data();
1318:
1.172 markus 1319: /* Force a password change */
1320: if (s->authctxt->force_pwchange) {
1321: do_setusercontext(pw);
1322: child_close_fds();
1323: do_pwchange(s);
1324: exit(1);
1325: }
1326:
1.127 markus 1327: /* login(1) is only called if we execute the login shell */
1328: if (options.use_login && command != NULL)
1329: options.use_login = 0;
1330:
1331: /*
1332: * Login(1) does this as well, and it needs uid 0 for the "-h"
1333: * switch, so we let login(1) to this for us.
1334: */
1335: if (!options.use_login) {
1336: do_nologin(pw);
1337: do_setusercontext(pw);
1338: }
1339:
1340: /*
1341: * Get the shell from the password data. An empty shell field is
1342: * legal, and means /bin/sh.
1343: */
1344: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1345:
1346: /*
1347: * Make sure $SHELL points to the shell from the password file,
1348: * even if shell is overridden from login.conf
1349: */
1350: env = do_setup_env(s, shell);
1351:
1.127 markus 1352: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1353:
1.26 millert 1354: /* we have to stash the hostname before we close our socket. */
1355: if (options.use_login)
1.70 stevesk 1356: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1357: options.use_dns);
1.1 markus 1358: /*
1359: * Close the connection descriptors; note that this is the child, and
1360: * the server will still have the socket open, and it is important
1361: * that we do not shutdown it. Note that the descriptors cannot be
1362: * closed before building the environment, as we call
1363: * get_remote_ipaddr there.
1364: */
1.172 markus 1365: child_close_fds();
1.1 markus 1366:
1367: /*
1.125 deraadt 1368: * Must take new environment into use so that .ssh/rc,
1369: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1370: */
1371: environ = env;
1.170 jakob 1372:
1373: #ifdef KRB5
1374: /*
1375: * At this point, we check to see if AFS is active and if we have
1376: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1377: * if we can (and need to) extend the ticket into an AFS token. If
1378: * we don't do this, we run into potential problems if the user's
1379: * home directory is in AFS and it's not world-readable.
1380: */
1381:
1382: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1383: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1384: char cell[64];
1385:
1386: debug("Getting AFS token");
1387:
1388: k_setpag();
1389:
1390: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1391: krb5_afslog(s->authctxt->krb5_ctx,
1392: s->authctxt->krb5_fwd_ccache, cell, NULL);
1393:
1394: krb5_afslog_home(s->authctxt->krb5_ctx,
1395: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1396: }
1397: #endif
1.104 markus 1398:
1.188 djm 1399: /* Change current directory to the user's home directory. */
1.104 markus 1400: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1401: /* Suppress missing homedir warning for chroot case */
1402: r = login_getcapbool(lc, "requirehome", 0);
1.254 djm 1403: if (r || options.chroot_directory == NULL ||
1404: strcasecmp(options.chroot_directory, "none") == 0)
1.239 djm 1405: fprintf(stderr, "Could not chdir to home "
1406: "directory %s: %s\n", pw->pw_dir,
1407: strerror(errno));
1408: if (r)
1.104 markus 1409: exit(1);
1410: }
1.230 djm 1411:
1412: closefrom(STDERR_FILENO + 1);
1.1 markus 1413:
1.127 markus 1414: if (!options.use_login)
1415: do_rc_files(s, shell);
1.67 markus 1416:
1417: /* restore SIGPIPE for child */
1.217 stevesk 1418: signal(SIGPIPE, SIG_DFL);
1.67 markus 1419:
1.248 djm 1420: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1421: printf("This service allows sftp connections only.\n");
1422: fflush(NULL);
1423: exit(1);
1424: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1425: extern int optind, optreset;
1426: int i;
1427: char *p, *args;
1428:
1.246 stevesk 1429: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1430: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1431: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1432: if (i < ARGV_MAX - 1)
1433: argv[i++] = p;
1434: argv[i] = NULL;
1435: optind = optreset = 1;
1436: __progname = argv[0];
1.226 djm 1437: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1438: }
1.247 djm 1439:
1440: fflush(NULL);
1.225 markus 1441:
1.127 markus 1442: if (options.use_login) {
1.130 provos 1443: launch_login(pw, hostname);
1444: /* NEVERREACHED */
1.127 markus 1445: }
1446:
1447: /* Get the last component of the shell name. */
1448: if ((shell0 = strrchr(shell, '/')) != NULL)
1449: shell0++;
1450: else
1451: shell0 = shell;
1452:
1.1 markus 1453: /*
1454: * If we have no command, execute the shell. In this case, the shell
1455: * name to be passed in argv[0] is preceded by '-' to indicate that
1456: * this is a login shell.
1457: */
1458: if (!command) {
1.127 markus 1459: char argv0[256];
1.1 markus 1460:
1.127 markus 1461: /* Start the shell. Set initial character to '-'. */
1462: argv0[0] = '-';
1.1 markus 1463:
1.127 markus 1464: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1465: >= sizeof(argv0) - 1) {
1.127 markus 1466: errno = EINVAL;
1.1 markus 1467: perror(shell);
1468: exit(1);
1.127 markus 1469: }
1.1 markus 1470:
1.127 markus 1471: /* Execute the shell. */
1472: argv[0] = argv0;
1473: argv[1] = NULL;
1474: execve(shell, argv, env);
1475:
1476: /* Executing the shell failed. */
1477: perror(shell);
1478: exit(1);
1.1 markus 1479: }
1480: /*
1481: * Execute the command using the user's shell. This uses the -c
1482: * option to execute the command.
1483: */
1.127 markus 1484: argv[0] = (char *) shell0;
1.1 markus 1485: argv[1] = "-c";
1486: argv[2] = (char *) command;
1487: argv[3] = NULL;
1488: execve(shell, argv, env);
1489: perror(shell);
1490: exit(1);
1491: }
1492:
1.237 djm 1493: void
1494: session_unused(int id)
1495: {
1496: debug3("%s: session id %d unused", __func__, id);
1497: if (id >= options.max_sessions ||
1498: id >= sessions_nalloc) {
1499: fatal("%s: insane session id %d (max %d nalloc %d)",
1500: __func__, id, options.max_sessions, sessions_nalloc);
1501: }
1502: bzero(&sessions[id], sizeof(*sessions));
1503: sessions[id].self = id;
1504: sessions[id].used = 0;
1505: sessions[id].chanid = -1;
1506: sessions[id].ptyfd = -1;
1507: sessions[id].ttyfd = -1;
1508: sessions[id].ptymaster = -1;
1509: sessions[id].x11_chanids = NULL;
1510: sessions[id].next_unused = sessions_first_unused;
1511: sessions_first_unused = id;
1512: }
1513:
1.1 markus 1514: Session *
1515: session_new(void)
1516: {
1.237 djm 1517: Session *s, *tmp;
1518:
1519: if (sessions_first_unused == -1) {
1520: if (sessions_nalloc >= options.max_sessions)
1521: return NULL;
1522: debug2("%s: allocate (allocated %d max %d)",
1523: __func__, sessions_nalloc, options.max_sessions);
1524: tmp = xrealloc(sessions, sessions_nalloc + 1,
1525: sizeof(*sessions));
1526: if (tmp == NULL) {
1527: error("%s: cannot allocate %d sessions",
1528: __func__, sessions_nalloc + 1);
1529: return NULL;
1530: }
1531: sessions = tmp;
1532: session_unused(sessions_nalloc++);
1533: }
1534:
1535: if (sessions_first_unused >= sessions_nalloc ||
1536: sessions_first_unused < 0) {
1537: fatal("%s: insane first_unused %d max %d nalloc %d",
1538: __func__, sessions_first_unused, options.max_sessions,
1539: sessions_nalloc);
1540: }
1541:
1542: s = &sessions[sessions_first_unused];
1543: if (s->used) {
1544: fatal("%s: session %d already used",
1545: __func__, sessions_first_unused);
1546: }
1547: sessions_first_unused = s->next_unused;
1548: s->used = 1;
1549: s->next_unused = -1;
1550: debug("session_new: session %d", s->self);
1551:
1552: return s;
1.1 markus 1553: }
1554:
1.94 itojun 1555: static void
1.1 markus 1556: session_dump(void)
1557: {
1558: int i;
1.237 djm 1559: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1560: Session *s = &sessions[i];
1.237 djm 1561:
1562: debug("dump: used %d next_unused %d session %d %p "
1563: "channel %d pid %ld",
1.1 markus 1564: s->used,
1.237 djm 1565: s->next_unused,
1.1 markus 1566: s->self,
1567: s,
1568: s->chanid,
1.137 mpech 1569: (long)s->pid);
1.1 markus 1570: }
1571: }
1572:
1.2 markus 1573: int
1.97 markus 1574: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1575: {
1576: Session *s = session_new();
1577: debug("session_open: channel %d", chanid);
1578: if (s == NULL) {
1579: error("no more sessions");
1580: return 0;
1581: }
1.97 markus 1582: s->authctxt = authctxt;
1583: s->pw = authctxt->pw;
1.167 djm 1584: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1585: fatal("no user for session %d", s->self);
1.2 markus 1586: debug("session_open: session %d: link with channel %d", s->self, chanid);
1587: s->chanid = chanid;
1588: return 1;
1589: }
1590:
1.130 provos 1591: Session *
1592: session_by_tty(char *tty)
1593: {
1594: int i;
1.237 djm 1595: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1596: Session *s = &sessions[i];
1597: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1598: debug("session_by_tty: session %d tty %s", i, tty);
1599: return s;
1600: }
1601: }
1602: debug("session_by_tty: unknown tty %.100s", tty);
1603: session_dump();
1604: return NULL;
1605: }
1606:
1.94 itojun 1607: static Session *
1.2 markus 1608: session_by_channel(int id)
1609: {
1610: int i;
1.237 djm 1611: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1612: Session *s = &sessions[i];
1613: if (s->used && s->chanid == id) {
1.237 djm 1614: debug("session_by_channel: session %d channel %d",
1615: i, id);
1.2 markus 1616: return s;
1617: }
1618: }
1619: debug("session_by_channel: unknown channel %d", id);
1620: session_dump();
1621: return NULL;
1622: }
1623:
1.94 itojun 1624: static Session *
1.184 djm 1625: session_by_x11_channel(int id)
1626: {
1627: int i, j;
1628:
1.237 djm 1629: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1630: Session *s = &sessions[i];
1631:
1632: if (s->x11_chanids == NULL || !s->used)
1633: continue;
1634: for (j = 0; s->x11_chanids[j] != -1; j++) {
1635: if (s->x11_chanids[j] == id) {
1636: debug("session_by_x11_channel: session %d "
1637: "channel %d", s->self, id);
1638: return s;
1639: }
1640: }
1641: }
1642: debug("session_by_x11_channel: unknown channel %d", id);
1643: session_dump();
1644: return NULL;
1645: }
1646:
1647: static Session *
1.2 markus 1648: session_by_pid(pid_t pid)
1649: {
1650: int i;
1.137 mpech 1651: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1652: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1653: Session *s = &sessions[i];
1654: if (s->used && s->pid == pid)
1655: return s;
1656: }
1.137 mpech 1657: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1658: session_dump();
1659: return NULL;
1660: }
1661:
1.94 itojun 1662: static int
1.2 markus 1663: session_window_change_req(Session *s)
1664: {
1665: s->col = packet_get_int();
1666: s->row = packet_get_int();
1667: s->xpixel = packet_get_int();
1668: s->ypixel = packet_get_int();
1.116 markus 1669: packet_check_eom();
1.2 markus 1670: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1671: return 1;
1672: }
1673:
1.94 itojun 1674: static int
1.2 markus 1675: session_pty_req(Session *s)
1676: {
1.45 markus 1677: u_int len;
1.72 stevesk 1678: int n_bytes;
1.132 markus 1679:
1.86 markus 1680: if (no_pty_flag) {
1681: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1682: return 0;
1.86 markus 1683: }
1684: if (s->ttyfd != -1) {
1685: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1686: return 0;
1.86 markus 1687: }
1688:
1.2 markus 1689: s->term = packet_get_string(&len);
1.86 markus 1690:
1691: if (compat20) {
1692: s->col = packet_get_int();
1693: s->row = packet_get_int();
1694: } else {
1695: s->row = packet_get_int();
1696: s->col = packet_get_int();
1697: }
1.2 markus 1698: s->xpixel = packet_get_int();
1699: s->ypixel = packet_get_int();
1700:
1701: if (strcmp(s->term, "") == 0) {
1.265 djm 1702: free(s->term);
1.2 markus 1703: s->term = NULL;
1704: }
1.86 markus 1705:
1.2 markus 1706: /* Allocate a pty and open it. */
1.86 markus 1707: debug("Allocating pty.");
1.237 djm 1708: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1709: sizeof(s->tty)))) {
1.265 djm 1710: free(s->term);
1.2 markus 1711: s->term = NULL;
1712: s->ptyfd = -1;
1713: s->ttyfd = -1;
1714: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1715: return 0;
1.2 markus 1716: }
1717: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1718:
1719: /* for SSH1 the tty modes length is not given */
1720: if (!compat20)
1721: n_bytes = packet_remaining();
1722: tty_parse_modes(s->ttyfd, &n_bytes);
1723:
1.130 provos 1724: if (!use_privsep)
1725: pty_setowner(s->pw, s->tty);
1.86 markus 1726:
1727: /* Set window size from the packet. */
1.2 markus 1728: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1729:
1.116 markus 1730: packet_check_eom();
1.9 markus 1731: session_proctitle(s);
1.2 markus 1732: return 1;
1733: }
1734:
1.94 itojun 1735: static int
1.7 markus 1736: session_subsystem_req(Session *s)
1737: {
1.105 markus 1738: struct stat st;
1.45 markus 1739: u_int len;
1.7 markus 1740: int success = 0;
1.205 djm 1741: char *prog, *cmd, *subsys = packet_get_string(&len);
1.182 djm 1742: u_int i;
1.7 markus 1743:
1.116 markus 1744: packet_check_eom();
1.255 djm 1745: logit("subsystem request for %.100s by user %s", subsys,
1746: s->pw->pw_name);
1.18 jakob 1747:
1748: for (i = 0; i < options.num_subsystems; i++) {
1.105 markus 1749: if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1750: prog = options.subsystem_command[i];
1751: cmd = options.subsystem_args[i];
1.249 dtucker 1752: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1753: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1754: debug("subsystem: %s", prog);
1.225 markus 1755: } else {
1.249 dtucker 1756: if (stat(prog, &st) < 0)
1757: debug("subsystem: cannot stat %s: %s",
1758: prog, strerror(errno));
1.225 markus 1759: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1760: debug("subsystem: exec() %s", cmd);
1.105 markus 1761: }
1.237 djm 1762: success = do_exec(s, cmd) == 0;
1.122 markus 1763: break;
1.18 jakob 1764: }
1765: }
1766:
1767: if (!success)
1.155 itojun 1768: logit("subsystem request for %.100s failed, subsystem not found",
1.105 markus 1769: subsys);
1.7 markus 1770:
1.265 djm 1771: free(subsys);
1.7 markus 1772: return success;
1773: }
1774:
1.94 itojun 1775: static int
1.7 markus 1776: session_x11_req(Session *s)
1777: {
1.81 markus 1778: int success;
1.7 markus 1779:
1.184 djm 1780: if (s->auth_proto != NULL || s->auth_data != NULL) {
1781: error("session_x11_req: session %d: "
1.190 stevesk 1782: "x11 forwarding already active", s->self);
1.184 djm 1783: return 0;
1784: }
1.7 markus 1785: s->single_connection = packet_get_char();
1786: s->auth_proto = packet_get_string(NULL);
1787: s->auth_data = packet_get_string(NULL);
1788: s->screen = packet_get_int();
1.116 markus 1789: packet_check_eom();
1.7 markus 1790:
1.81 markus 1791: success = session_setup_x11fwd(s);
1792: if (!success) {
1.265 djm 1793: free(s->auth_proto);
1794: free(s->auth_data);
1.84 markus 1795: s->auth_proto = NULL;
1796: s->auth_data = NULL;
1.7 markus 1797: }
1.81 markus 1798: return success;
1.7 markus 1799: }
1800:
1.94 itojun 1801: static int
1.19 markus 1802: session_shell_req(Session *s)
1803: {
1.116 markus 1804: packet_check_eom();
1.237 djm 1805: return do_exec(s, NULL) == 0;
1.19 markus 1806: }
1807:
1.94 itojun 1808: static int
1.19 markus 1809: session_exec_req(Session *s)
1810: {
1.237 djm 1811: u_int len, success;
1812:
1.19 markus 1813: char *command = packet_get_string(&len);
1.116 markus 1814: packet_check_eom();
1.237 djm 1815: success = do_exec(s, command) == 0;
1.265 djm 1816: free(command);
1.237 djm 1817: return success;
1.19 markus 1818: }
1819:
1.94 itojun 1820: static int
1.157 markus 1821: session_break_req(Session *s)
1822: {
1823:
1.175 deraadt 1824: packet_get_int(); /* ignored */
1.157 markus 1825: packet_check_eom();
1826:
1.259 djm 1827: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1828: return 0;
1829: return 1;
1830: }
1831:
1832: static int
1.173 djm 1833: session_env_req(Session *s)
1834: {
1835: char *name, *val;
1836: u_int name_len, val_len, i;
1837:
1838: name = packet_get_string(&name_len);
1839: val = packet_get_string(&val_len);
1840: packet_check_eom();
1841:
1842: /* Don't set too many environment variables */
1843: if (s->num_env > 128) {
1844: debug2("Ignoring env request %s: too many env vars", name);
1845: goto fail;
1846: }
1847:
1848: for (i = 0; i < options.num_accept_env; i++) {
1849: if (match_pattern(name, options.accept_env[i])) {
1850: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.201 djm 1851: s->env = xrealloc(s->env, s->num_env + 1,
1852: sizeof(*s->env));
1.173 djm 1853: s->env[s->num_env].name = name;
1854: s->env[s->num_env].val = val;
1855: s->num_env++;
1856: return (1);
1857: }
1858: }
1859: debug2("Ignoring env request %s: disallowed name", name);
1860:
1861: fail:
1.265 djm 1862: free(name);
1863: free(val);
1.173 djm 1864: return (0);
1865: }
1866:
1867: static int
1.43 markus 1868: session_auth_agent_req(Session *s)
1869: {
1870: static int called = 0;
1.116 markus 1871: packet_check_eom();
1.235 pyr 1872: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1873: debug("session_auth_agent_req: no_agent_forwarding_flag");
1874: return 0;
1875: }
1.43 markus 1876: if (called) {
1877: return 0;
1878: } else {
1879: called = 1;
1880: return auth_input_request_forwarding(s->pw);
1881: }
1882: }
1883:
1.123 markus 1884: int
1885: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1886: {
1887: int success = 0;
1888: Session *s;
1889:
1.123 markus 1890: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1891: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1892: c->self, rtype);
1893: return 0;
1894: }
1895: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1896:
1897: /*
1.64 markus 1898: * a session is in LARVAL state until a shell, a command
1899: * or a subsystem is executed
1.2 markus 1900: */
1901: if (c->type == SSH_CHANNEL_LARVAL) {
1902: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1903: success = session_shell_req(s);
1.2 markus 1904: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1905: success = session_exec_req(s);
1.2 markus 1906: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1907: success = session_pty_req(s);
1.7 markus 1908: } else if (strcmp(rtype, "x11-req") == 0) {
1909: success = session_x11_req(s);
1.43 markus 1910: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1911: success = session_auth_agent_req(s);
1.7 markus 1912: } else if (strcmp(rtype, "subsystem") == 0) {
1913: success = session_subsystem_req(s);
1.173 djm 1914: } else if (strcmp(rtype, "env") == 0) {
1915: success = session_env_req(s);
1.2 markus 1916: }
1917: }
1918: if (strcmp(rtype, "window-change") == 0) {
1919: success = session_window_change_req(s);
1.177 djm 1920: } else if (strcmp(rtype, "break") == 0) {
1921: success = session_break_req(s);
1.2 markus 1922: }
1.177 djm 1923:
1.123 markus 1924: return success;
1.2 markus 1925: }
1926:
1927: void
1.256 djm 1928: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1929: int is_tty)
1.2 markus 1930: {
1931: if (!compat20)
1932: fatal("session_set_fds: called for proto != 2.0");
1933: /*
1934: * now that have a child and a pipe to the child,
1935: * we can activate our channel and register the fd's
1936: */
1937: if (s->chanid == -1)
1938: fatal("no channel for session %d", s->self);
1939: channel_set_fds(s->chanid,
1940: fdout, fdin, fderr,
1.256 djm 1941: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1942: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1943: }
1944:
1.85 markus 1945: /*
1946: * Function to perform pty cleanup. Also called if we get aborted abnormally
1947: * (e.g., due to a dropped connection).
1948: */
1.130 provos 1949: void
1.165 markus 1950: session_pty_cleanup2(Session *s)
1.1 markus 1951: {
1.85 markus 1952: if (s == NULL) {
1953: error("session_pty_cleanup: no session");
1954: return;
1955: }
1956: if (s->ttyfd == -1)
1.1 markus 1957: return;
1958:
1.54 stevesk 1959: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1960:
1961: /* Record that the user has logged out. */
1.85 markus 1962: if (s->pid != 0)
1963: record_logout(s->pid, s->tty);
1.1 markus 1964:
1965: /* Release the pseudo-tty. */
1.130 provos 1966: if (getuid() == 0)
1967: pty_release(s->tty);
1.1 markus 1968:
1969: /*
1970: * Close the server side of the socket pairs. We must do this after
1971: * the pty cleanup, so that another process doesn't get this pty
1972: * while we're still cleaning up.
1973: */
1.237 djm 1974: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
1975: error("close(s->ptymaster/%d): %s",
1976: s->ptymaster, strerror(errno));
1.108 markus 1977:
1978: /* unlink pty from session */
1979: s->ttyfd = -1;
1.2 markus 1980: }
1981:
1.130 provos 1982: void
1.165 markus 1983: session_pty_cleanup(Session *s)
1.130 provos 1984: {
1.165 markus 1985: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 1986: }
1987:
1.147 markus 1988: static char *
1989: sig2name(int sig)
1990: {
1991: #define SSH_SIG(x) if (sig == SIG ## x) return #x
1992: SSH_SIG(ABRT);
1993: SSH_SIG(ALRM);
1994: SSH_SIG(FPE);
1995: SSH_SIG(HUP);
1996: SSH_SIG(ILL);
1997: SSH_SIG(INT);
1998: SSH_SIG(KILL);
1999: SSH_SIG(PIPE);
2000: SSH_SIG(QUIT);
2001: SSH_SIG(SEGV);
2002: SSH_SIG(TERM);
2003: SSH_SIG(USR1);
2004: SSH_SIG(USR2);
2005: #undef SSH_SIG
2006: return "SIG@openssh.com";
2007: }
2008:
1.94 itojun 2009: static void
1.184 djm 2010: session_close_x11(int id)
2011: {
2012: Channel *c;
2013:
1.189 markus 2014: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2015: debug("session_close_x11: x11 channel %d missing", id);
2016: } else {
2017: /* Detach X11 listener */
2018: debug("session_close_x11: detach x11 channel %d", id);
2019: channel_cancel_cleanup(id);
2020: if (c->ostate != CHAN_OUTPUT_CLOSED)
2021: chan_mark_dead(c);
2022: }
2023: }
2024:
2025: static void
2026: session_close_single_x11(int id, void *arg)
2027: {
2028: Session *s;
2029: u_int i;
2030:
2031: debug3("session_close_single_x11: channel %d", id);
2032: channel_cancel_cleanup(id);
1.221 stevesk 2033: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2034: fatal("session_close_single_x11: no x11 channel %d", id);
2035: for (i = 0; s->x11_chanids[i] != -1; i++) {
2036: debug("session_close_single_x11: session %d: "
2037: "closing channel %d", s->self, s->x11_chanids[i]);
2038: /*
2039: * The channel "id" is already closing, but make sure we
2040: * close all of its siblings.
2041: */
2042: if (s->x11_chanids[i] != id)
2043: session_close_x11(s->x11_chanids[i]);
2044: }
1.265 djm 2045: free(s->x11_chanids);
1.184 djm 2046: s->x11_chanids = NULL;
1.265 djm 2047: free(s->display);
2048: s->display = NULL;
2049: free(s->auth_proto);
2050: s->auth_proto = NULL;
2051: free(s->auth_data);
2052: s->auth_data = NULL;
2053: free(s->auth_display);
2054: s->auth_display = NULL;
1.184 djm 2055: }
2056:
2057: static void
1.2 markus 2058: session_exit_message(Session *s, int status)
2059: {
2060: Channel *c;
1.124 markus 2061:
2062: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2063: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2064: s->self, s->chanid);
1.137 mpech 2065: debug("session_exit_message: session %d channel %d pid %ld",
2066: s->self, s->chanid, (long)s->pid);
1.2 markus 2067:
2068: if (WIFEXITED(status)) {
1.124 markus 2069: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2070: packet_put_int(WEXITSTATUS(status));
2071: packet_send();
2072: } else if (WIFSIGNALED(status)) {
1.124 markus 2073: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2074: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2075: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2076: packet_put_cstring("");
2077: packet_put_cstring("");
2078: packet_send();
2079: } else {
2080: /* Some weird exit cause. Just exit. */
2081: packet_disconnect("wait returned status %04x.", status);
2082: }
2083:
2084: /* disconnect channel */
2085: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2086:
2087: /*
2088: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2089: * the channel gets EOF. The session will be then be closed
1.187 djm 2090: * by session_close_by_channel when the childs close their fds.
2091: */
2092: channel_register_cleanup(c->self, session_close_by_channel, 1);
2093:
1.5 markus 2094: /*
2095: * emulate a write failure with 'chan_write_failed', nobody will be
2096: * interested in data we write.
2097: * Note that we must not call 'chan_read_failed', since there could
2098: * be some more data waiting in the pipe.
2099: */
1.8 markus 2100: if (c->ostate != CHAN_OUTPUT_CLOSED)
2101: chan_write_failed(c);
1.2 markus 2102: }
2103:
1.130 provos 2104: void
1.85 markus 2105: session_close(Session *s)
1.2 markus 2106: {
1.182 djm 2107: u_int i;
1.173 djm 2108:
1.137 mpech 2109: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165 markus 2110: if (s->ttyfd != -1)
1.85 markus 2111: session_pty_cleanup(s);
1.265 djm 2112: free(s->term);
2113: free(s->display);
2114: free(s->x11_chanids);
2115: free(s->auth_display);
2116: free(s->auth_data);
2117: free(s->auth_proto);
1.219 djm 2118: if (s->env != NULL) {
2119: for (i = 0; i < s->num_env; i++) {
1.265 djm 2120: free(s->env[i].name);
2121: free(s->env[i].val);
1.219 djm 2122: }
1.265 djm 2123: free(s->env);
1.173 djm 2124: }
1.9 markus 2125: session_proctitle(s);
1.237 djm 2126: session_unused(s->self);
1.2 markus 2127: }
2128:
2129: void
2130: session_close_by_pid(pid_t pid, int status)
2131: {
2132: Session *s = session_by_pid(pid);
2133: if (s == NULL) {
1.137 mpech 2134: debug("session_close_by_pid: no session for pid %ld",
2135: (long)pid);
1.2 markus 2136: return;
2137: }
2138: if (s->chanid != -1)
2139: session_exit_message(s, status);
1.187 djm 2140: if (s->ttyfd != -1)
2141: session_pty_cleanup(s);
1.197 djm 2142: s->pid = 0;
1.98 markus 2143: }
2144:
1.2 markus 2145: /*
2146: * this is called when a channel dies before
2147: * the session 'child' itself dies
2148: */
2149: void
2150: session_close_by_channel(int id, void *arg)
2151: {
2152: Session *s = session_by_channel(id);
1.187 djm 2153: u_int i;
1.184 djm 2154:
1.2 markus 2155: if (s == NULL) {
1.107 markus 2156: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2157: return;
2158: }
1.137 mpech 2159: debug("session_close_by_channel: channel %d child %ld",
2160: id, (long)s->pid);
1.107 markus 2161: if (s->pid != 0) {
2162: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2163: /*
2164: * delay detach of session, but release pty, since
2165: * the fd's to the child are already closed
2166: */
1.165 markus 2167: if (s->ttyfd != -1)
1.108 markus 2168: session_pty_cleanup(s);
1.107 markus 2169: return;
2170: }
2171: /* detach by removing callback */
1.2 markus 2172: channel_cancel_cleanup(s->chanid);
1.187 djm 2173:
2174: /* Close any X11 listeners associated with this session */
2175: if (s->x11_chanids != NULL) {
2176: for (i = 0; s->x11_chanids[i] != -1; i++) {
2177: session_close_x11(s->x11_chanids[i]);
2178: s->x11_chanids[i] = -1;
2179: }
2180: }
2181:
1.2 markus 2182: s->chanid = -1;
1.106 markus 2183: session_close(s);
2184: }
2185:
2186: void
1.130 provos 2187: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2188: {
2189: int i;
1.237 djm 2190: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2191: Session *s = &sessions[i];
1.130 provos 2192: if (s->used) {
2193: if (closefunc != NULL)
2194: closefunc(s);
2195: else
2196: session_close(s);
2197: }
1.2 markus 2198: }
1.9 markus 2199: }
2200:
1.94 itojun 2201: static char *
1.9 markus 2202: session_tty_list(void)
2203: {
2204: static char buf[1024];
2205: int i;
2206: buf[0] = '\0';
1.237 djm 2207: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2208: Session *s = &sessions[i];
2209: if (s->used && s->ttyfd != -1) {
2210: if (buf[0] != '\0')
2211: strlcat(buf, ",", sizeof buf);
2212: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2213: }
2214: }
2215: if (buf[0] == '\0')
2216: strlcpy(buf, "notty", sizeof buf);
2217: return buf;
2218: }
2219:
2220: void
2221: session_proctitle(Session *s)
2222: {
2223: if (s->pw == NULL)
2224: error("no user for session %d", s->self);
2225: else
2226: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2227: }
2228:
2229: int
2230: session_setup_x11fwd(Session *s)
2231: {
2232: struct stat st;
1.109 stevesk 2233: char display[512], auth_display[512];
2234: char hostname[MAXHOSTNAMELEN];
1.184 djm 2235: u_int i;
1.81 markus 2236:
2237: if (no_x11_forwarding_flag) {
2238: packet_send_debug("X11 forwarding disabled in user configuration file.");
2239: return 0;
2240: }
2241: if (!options.x11_forwarding) {
2242: debug("X11 forwarding disabled in server configuration file.");
2243: return 0;
2244: }
2245: if (!options.xauth_location ||
2246: (stat(options.xauth_location, &st) == -1)) {
2247: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2248: return 0;
2249: }
2250: if (options.use_login) {
2251: packet_send_debug("X11 forwarding disabled; "
2252: "not compatible with UseLogin=yes.");
1.81 markus 2253: return 0;
2254: }
1.87 markus 2255: if (s->display != NULL) {
1.81 markus 2256: debug("X11 display already set.");
2257: return 0;
2258: }
1.140 deraadt 2259: if (x11_create_display_inet(options.x11_display_offset,
2260: options.x11_use_localhost, s->single_connection,
1.184 djm 2261: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2262: debug("x11_create_display_inet failed.");
1.81 markus 2263: return 0;
1.184 djm 2264: }
2265: for (i = 0; s->x11_chanids[i] != -1; i++) {
2266: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2267: session_close_single_x11, 0);
1.81 markus 2268: }
1.109 stevesk 2269:
2270: /* Set up a suitable value for the DISPLAY variable. */
2271: if (gethostname(hostname, sizeof(hostname)) < 0)
2272: fatal("gethostname: %.100s", strerror(errno));
2273: /*
2274: * auth_display must be used as the displayname when the
2275: * authorization entry is added with xauth(1). This will be
2276: * different than the DISPLAY string for localhost displays.
2277: */
1.119 stevesk 2278: if (options.x11_use_localhost) {
1.140 deraadt 2279: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2280: s->display_number, s->screen);
1.140 deraadt 2281: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2282: s->display_number, s->screen);
1.109 stevesk 2283: s->display = xstrdup(display);
1.118 stevesk 2284: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2285: } else {
1.140 deraadt 2286: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2287: s->display_number, s->screen);
2288: s->display = xstrdup(display);
1.118 stevesk 2289: s->auth_display = xstrdup(display);
1.109 stevesk 2290: }
2291:
1.81 markus 2292: return 1;
1.2 markus 2293: }
2294:
1.94 itojun 2295: static void
1.49 markus 2296: do_authenticated2(Authctxt *authctxt)
1.2 markus 2297: {
1.97 markus 2298: server_loop2(authctxt);
1.165 markus 2299: }
2300:
2301: void
2302: do_cleanup(Authctxt *authctxt)
2303: {
2304: static int called = 0;
2305:
2306: debug("do_cleanup");
2307:
2308: /* no cleanup if we're in the child for login shell */
2309: if (is_child)
2310: return;
2311:
2312: /* avoid double cleanup */
2313: if (called)
2314: return;
2315: called = 1;
2316:
1.218 markus 2317: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2318: return;
2319: #ifdef KRB5
2320: if (options.kerberos_ticket_cleanup &&
2321: authctxt->krb5_ctx)
2322: krb5_cleanup_proc(authctxt);
1.161 markus 2323: #endif
1.165 markus 2324:
2325: #ifdef GSSAPI
2326: if (compat20 && options.gss_cleanup_creds)
2327: ssh_gssapi_cleanup_creds();
2328: #endif
2329:
2330: /* remove agent socket */
2331: auth_sock_cleanup_proc(authctxt->pw);
2332:
2333: /*
2334: * Cleanup ptys/utmp only if privsep is disabled,
2335: * or if running in monitor.
2336: */
2337: if (!use_privsep || mm_is_monitor())
2338: session_destroy_all(session_pty_cleanup2);
1.1 markus 2339: }
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