Annotation of src/usr.bin/ssh/session.c, Revision 1.271
1.271 ! djm 1: /* $OpenBSD: session.c,v 1.270 2014/01/31 16:39:19 tedu 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:
1.269 dtucker 427: #define USE_PIPES 1
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;
1.267 djm 715: const char *forced = NULL;
716: char session_type[1024], *tty = NULL;
1.237 djm 717:
1.210 dtucker 718: if (options.adm_forced_command) {
719: original_command = command;
720: command = options.adm_forced_command;
1.267 djm 721: forced = "(config)";
1.210 dtucker 722: } else if (forced_command) {
1.90 markus 723: original_command = command;
724: command = forced_command;
1.267 djm 725: forced = "(key-option)";
726: }
727: if (forced != NULL) {
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;
1.267 djm 733: snprintf(session_type, sizeof(session_type),
734: "forced-command %s '%.900s'", forced, command);
735: } else if (s->is_subsystem) {
736: snprintf(session_type, sizeof(session_type),
737: "subsystem '%.900s'", s->subsys);
738: } else if (command == NULL) {
739: snprintf(session_type, sizeof(session_type), "shell");
740: } else {
741: /* NB. we don't log unforced commands to preserve privacy */
742: snprintf(session_type, sizeof(session_type), "command");
1.90 markus 743: }
1.163 markus 744:
1.267 djm 745: if (s->ttyfd != -1) {
746: tty = s->tty;
747: if (strncmp(tty, "/dev/", 5) == 0)
748: tty += 5;
749: }
750:
751: verbose("Starting session: %s%s%s for %s from %.200s port %d",
752: session_type,
753: tty == NULL ? "" : " on ",
754: tty == NULL ? "" : tty,
755: s->pw->pw_name,
756: get_remote_ipaddr(),
757: get_remote_port());
758:
1.163 markus 759: #ifdef GSSAPI
760: if (options.gss_authentication) {
761: temporarily_use_uid(s->pw);
762: ssh_gssapi_storecreds();
763: restore_uid();
764: }
765: #endif
1.90 markus 766: if (s->ttyfd != -1)
1.237 djm 767: ret = do_exec_pty(s, command);
1.90 markus 768: else
1.237 djm 769: ret = do_exec_no_pty(s, command);
1.90 markus 770:
1.92 markus 771: original_command = NULL;
1.179 dtucker 772:
773: /*
774: * Clear loginmsg: it's the child's responsibility to display
775: * it to the user, otherwise multiple sessions may accumulate
776: * multiple copies of the login messages.
777: */
778: buffer_clear(&loginmsg);
1.237 djm 779:
780: return ret;
1.90 markus 781: }
782:
783:
1.24 markus 784: /* administrative, login(1)-like work */
785: void
1.41 markus 786: do_login(Session *s, const char *command)
1.24 markus 787: {
788: socklen_t fromlen;
789: struct sockaddr_storage from;
790: struct passwd * pw = s->pw;
791: pid_t pid = getpid();
792:
793: /*
794: * Get IP address of client. If the connection is not a socket, let
795: * the address be 0.0.0.0.
796: */
797: memset(&from, 0, sizeof(from));
1.148 stevesk 798: fromlen = sizeof(from);
1.24 markus 799: if (packet_connection_is_on_socket()) {
800: if (getpeername(packet_get_connection_in(),
1.200 deraadt 801: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 802: debug("getpeername: %.100s", strerror(errno));
1.165 markus 803: cleanup_exit(255);
1.24 markus 804: }
805: }
1.25 markus 806:
1.24 markus 807: /* Record that there was a login on that tty from the remote host. */
1.133 markus 808: if (!use_privsep)
809: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
810: get_remote_name_or_ip(utmp_len,
1.158 markus 811: options.use_dns),
1.148 stevesk 812: (struct sockaddr *)&from, fromlen);
1.24 markus 813:
1.73 djm 814: if (check_quietlogin(s, command))
1.24 markus 815: return;
1.73 djm 816:
1.179 dtucker 817: display_loginmsg();
1.73 djm 818:
819: do_motd();
820: }
821:
822: /*
823: * Display the message of the day.
824: */
825: void
826: do_motd(void)
827: {
828: FILE *f;
829: char buf[256];
830:
1.24 markus 831: if (options.print_motd) {
1.28 millert 832: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
833: "/etc/motd"), "r");
1.24 markus 834: if (f) {
835: while (fgets(buf, sizeof(buf), f))
836: fputs(buf, stdout);
837: fclose(f);
838: }
1.2 markus 839: }
1.73 djm 840: }
841:
842:
843: /*
844: * Check for quiet login, either .hushlogin or command given.
845: */
846: int
847: check_quietlogin(Session *s, const char *command)
848: {
849: char buf[256];
1.96 dugsong 850: struct passwd *pw = s->pw;
1.73 djm 851: struct stat st;
852:
853: /* Return 1 if .hushlogin exists or a command given. */
854: if (command != NULL)
855: return 1;
856: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
857: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
858: return 1;
859: return 0;
1.1 markus 860: }
861:
862: /*
863: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 864: * already exists, its value is overridden.
1.1 markus 865: */
1.161 markus 866: void
1.45 markus 867: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 868: const char *value)
1.1 markus 869: {
1.164 markus 870: char **env;
871: u_int envsize;
1.45 markus 872: u_int i, namelen;
1.1 markus 873:
1.271 ! djm 874: if (strchr(name, '=') != NULL) {
! 875: error("Invalid environment variable \"%.100s\"", name);
! 876: return;
! 877: }
! 878:
1.1 markus 879: /*
880: * Find the slot where the value should be stored. If the variable
881: * already exists, we reuse the slot; otherwise we append a new slot
882: * at the end of the array, expanding if necessary.
883: */
884: env = *envp;
885: namelen = strlen(name);
886: for (i = 0; env[i]; i++)
887: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
888: break;
889: if (env[i]) {
890: /* Reuse the slot. */
1.265 djm 891: free(env[i]);
1.1 markus 892: } else {
893: /* New variable. Expand if necessary. */
1.164 markus 894: envsize = *envsizep;
895: if (i >= envsize - 1) {
896: if (envsize >= 1000)
897: fatal("child_set_env: too many env vars");
898: envsize += 50;
1.201 djm 899: env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1.164 markus 900: *envsizep = envsize;
1.1 markus 901: }
902: /* Need to set the NULL pointer at end of array beyond the new slot. */
903: env[i + 1] = NULL;
904: }
905:
906: /* Allocate space and format the variable in the appropriate slot. */
907: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
908: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
909: }
910:
911: /*
912: * Reads environment variables from the given file and adds/overrides them
913: * into the environment. If the file does not exist, this does nothing.
914: * Otherwise, it must consist of empty lines, comments (line starts with '#')
915: * and assignments of the form name=value. No other forms are allowed.
916: */
1.94 itojun 917: static void
1.45 markus 918: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 919: const char *filename)
1.1 markus 920: {
921: FILE *f;
922: char buf[4096];
923: char *cp, *value;
1.142 deraadt 924: u_int lineno = 0;
1.1 markus 925:
926: f = fopen(filename, "r");
927: if (!f)
928: return;
929:
930: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 931: if (++lineno > 1000)
932: fatal("Too many lines in environment file %s", filename);
1.1 markus 933: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
934: ;
935: if (!*cp || *cp == '#' || *cp == '\n')
936: continue;
1.224 gilles 937:
938: cp[strcspn(cp, "\n")] = '\0';
939:
1.1 markus 940: value = strchr(cp, '=');
941: if (value == NULL) {
1.142 deraadt 942: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
943: filename);
1.1 markus 944: continue;
945: }
1.14 deraadt 946: /*
947: * Replace the equals sign by nul, and advance value to
948: * the value string.
949: */
1.1 markus 950: *value = '\0';
951: value++;
952: child_set_env(env, envsize, cp, value);
953: }
954: fclose(f);
955: }
956:
1.127 markus 957: static char **
958: do_setup_env(Session *s, const char *shell)
1.1 markus 959: {
960: char buf[256];
1.127 markus 961: u_int i, envsize;
1.154 markus 962: char **env, *laddr;
1.127 markus 963: struct passwd *pw = s->pw;
1.1 markus 964:
965: /* Initialize the environment. */
966: envsize = 100;
1.220 djm 967: env = xcalloc(envsize, sizeof(char *));
1.1 markus 968: env[0] = NULL;
969:
1.161 markus 970: #ifdef GSSAPI
1.168 djm 971: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 972: * the childs environment as they see fit
973: */
974: ssh_gssapi_do_child(&env, &envsize);
975: #endif
976:
1.1 markus 977: if (!options.use_login) {
978: /* Set basic environment. */
1.173 djm 979: for (i = 0; i < s->num_env; i++)
1.178 deraadt 980: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 981: s->env[i].val);
982:
1.1 markus 983: child_set_env(&env, &envsize, "USER", pw->pw_name);
984: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
985: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 986: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
987: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
988: else
989: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 990:
991: snprintf(buf, sizeof buf, "%.200s/%.50s",
992: _PATH_MAILDIR, pw->pw_name);
993: child_set_env(&env, &envsize, "MAIL", buf);
994:
995: /* Normal systems set SHELL by default. */
996: child_set_env(&env, &envsize, "SHELL", shell);
997: }
998: if (getenv("TZ"))
999: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1000:
1001: /* Set custom environment options from RSA authentication. */
1.110 markus 1002: if (!options.use_login) {
1003: while (custom_environment) {
1004: struct envstring *ce = custom_environment;
1.143 deraadt 1005: char *str = ce->s;
1.127 markus 1006:
1.143 deraadt 1007: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 1008: ;
1.143 deraadt 1009: if (str[i] == '=') {
1010: str[i] = 0;
1011: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 1012: }
1013: custom_environment = ce->next;
1.265 djm 1014: free(ce->s);
1015: free(ce);
1.1 markus 1016: }
1017: }
1018:
1.149 stevesk 1019: /* SSH_CLIENT deprecated */
1.1 markus 1020: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 1021: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 1022: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1023:
1.154 markus 1024: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1025: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 1026: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1.265 djm 1027: free(laddr);
1.149 stevesk 1028: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1029:
1.60 markus 1030: if (s->ttyfd != -1)
1031: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1032: if (s->term)
1033: child_set_env(&env, &envsize, "TERM", s->term);
1034: if (s->display)
1035: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1036: if (original_command)
1037: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1038: original_command);
1.96 dugsong 1039: #ifdef KRB5
1040: if (s->authctxt->krb5_ticket_file)
1041: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1042: s->authctxt->krb5_ticket_file);
1.96 dugsong 1043: #endif
1.136 markus 1044: if (auth_sock_name != NULL)
1.1 markus 1045: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1046: auth_sock_name);
1.1 markus 1047:
1048: /* read $HOME/.ssh/environment. */
1.146 markus 1049: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1050: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1051: pw->pw_dir);
1.1 markus 1052: read_environment_file(&env, &envsize, buf);
1053: }
1054: if (debug_flag) {
1055: /* dump the environment */
1056: fprintf(stderr, "Environment:\n");
1057: for (i = 0; env[i]; i++)
1058: fprintf(stderr, " %.200s\n", env[i]);
1059: }
1.127 markus 1060: return env;
1061: }
1062:
1063: /*
1064: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1065: * first in this order).
1066: */
1067: static void
1068: do_rc_files(Session *s, const char *shell)
1069: {
1070: FILE *f = NULL;
1071: char cmd[1024];
1072: int do_xauth;
1073: struct stat st;
1074:
1075: do_xauth =
1076: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1077:
1.231 djm 1078: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1079: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.234 djm 1080: !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1081: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1082: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1083: if (debug_flag)
1084: fprintf(stderr, "Running %s\n", cmd);
1085: f = popen(cmd, "w");
1086: if (f) {
1087: if (do_xauth)
1088: fprintf(f, "%s %s\n", s->auth_proto,
1089: s->auth_data);
1090: pclose(f);
1091: } else
1092: fprintf(stderr, "Could not run %s\n",
1093: _PATH_SSH_USER_RC);
1094: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1095: if (debug_flag)
1096: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1097: _PATH_SSH_SYSTEM_RC);
1098: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1099: if (f) {
1100: if (do_xauth)
1101: fprintf(f, "%s %s\n", s->auth_proto,
1102: s->auth_data);
1103: pclose(f);
1104: } else
1105: fprintf(stderr, "Could not run %s\n",
1106: _PATH_SSH_SYSTEM_RC);
1107: } else if (do_xauth && options.xauth_location != NULL) {
1108: /* Add authority data to .Xauthority if appropriate. */
1109: if (debug_flag) {
1110: fprintf(stderr,
1.151 stevesk 1111: "Running %.500s remove %.100s\n",
1.165 markus 1112: options.xauth_location, s->auth_display);
1.151 stevesk 1113: fprintf(stderr,
1114: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1115: options.xauth_location, s->auth_display,
1116: s->auth_proto, s->auth_data);
1117: }
1118: snprintf(cmd, sizeof cmd, "%s -q -",
1119: options.xauth_location);
1120: f = popen(cmd, "w");
1121: if (f) {
1.151 stevesk 1122: fprintf(f, "remove %s\n",
1123: s->auth_display);
1.127 markus 1124: fprintf(f, "add %s %s %s\n",
1125: s->auth_display, s->auth_proto,
1126: s->auth_data);
1127: pclose(f);
1128: } else {
1129: fprintf(stderr, "Could not run %s\n",
1130: cmd);
1131: }
1132: }
1133: }
1134:
1135: static void
1136: do_nologin(struct passwd *pw)
1137: {
1138: FILE *f = NULL;
1.251 dtucker 1139: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1140: struct stat sb;
1.127 markus 1141:
1.260 guenther 1142: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1143: return;
1144: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1145:
1146: if (stat(nl, &sb) == -1) {
1147: if (nl != def_nl)
1.265 djm 1148: free(nl);
1.251 dtucker 1149: return;
1150: }
1151:
1152: /* /etc/nologin exists. Print its contents if we can and exit. */
1153: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1154: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1155: while (fgets(buf, sizeof(buf), f))
1156: fputs(buf, stderr);
1157: fclose(f);
1158: }
1.251 dtucker 1159: exit(254);
1.127 markus 1160: }
1161:
1.226 djm 1162: /*
1163: * Chroot into a directory after checking it for safety: all path components
1164: * must be root-owned directories with strict permissions.
1165: */
1166: static void
1167: safely_chroot(const char *path, uid_t uid)
1168: {
1169: const char *cp;
1170: char component[MAXPATHLEN];
1171: struct stat st;
1172:
1173: if (*path != '/')
1174: fatal("chroot path does not begin at root");
1175: if (strlen(path) >= sizeof(component))
1176: fatal("chroot path too long");
1177:
1178: /*
1179: * Descend the path, checking that each component is a
1180: * root-owned directory with strict permissions.
1181: */
1182: for (cp = path; cp != NULL;) {
1183: if ((cp = strchr(cp, '/')) == NULL)
1184: strlcpy(component, path, sizeof(component));
1185: else {
1186: cp++;
1187: memcpy(component, path, cp - path);
1188: component[cp - path] = '\0';
1189: }
1190:
1191: debug3("%s: checking '%s'", __func__, component);
1192:
1193: if (stat(component, &st) != 0)
1194: fatal("%s: stat(\"%s\"): %s", __func__,
1195: component, strerror(errno));
1196: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1197: fatal("bad ownership or modes for chroot "
1198: "directory %s\"%s\"",
1199: cp == NULL ? "" : "component ", component);
1200: if (!S_ISDIR(st.st_mode))
1201: fatal("chroot path %s\"%s\" is not a directory",
1202: cp == NULL ? "" : "component ", component);
1203:
1204: }
1205:
1206: if (chdir(path) == -1)
1207: fatal("Unable to chdir to chroot path \"%s\": "
1208: "%s", path, strerror(errno));
1209: if (chroot(path) == -1)
1210: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1211: if (chdir("/") == -1)
1212: fatal("%s: chdir(/) after chroot: %s",
1213: __func__, strerror(errno));
1214: verbose("Changed root directory to \"%s\"", path);
1215: }
1216:
1.127 markus 1217: /* Set login name, uid, gid, and groups. */
1.130 provos 1218: void
1.127 markus 1219: do_setusercontext(struct passwd *pw)
1220: {
1.227 djm 1221: char *chroot_path, *tmp;
1222:
1.127 markus 1223: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1224: /* Prepare groups */
1.127 markus 1225: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1226: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1227: perror("unable to set user context");
1228: exit(1);
1229: }
1.226 djm 1230:
1231: if (options.chroot_directory != NULL &&
1232: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1233: tmp = tilde_expand_filename(options.chroot_directory,
1234: pw->pw_uid);
1235: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1236: "u", pw->pw_name, (char *)NULL);
1.226 djm 1237: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1238: free(tmp);
1.226 djm 1239: free(chroot_path);
1.264 djm 1240: /* Make sure we don't attempt to chroot again */
1241: free(options.chroot_directory);
1242: options.chroot_directory = NULL;
1.226 djm 1243: }
1244:
1245: /* Set UID */
1246: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1247: perror("unable to set user context (setuser)");
1248: exit(1);
1249: }
1.264 djm 1250: } else if (options.chroot_directory != NULL &&
1251: strcasecmp(options.chroot_directory, "none") != 0) {
1252: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1253: }
1.264 djm 1254:
1.127 markus 1255: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1256: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1257: }
1258:
1.131 markus 1259: static void
1.172 markus 1260: do_pwchange(Session *s)
1261: {
1.179 dtucker 1262: fflush(NULL);
1.172 markus 1263: fprintf(stderr, "WARNING: Your password has expired.\n");
1264: if (s->ttyfd != -1) {
1.178 deraadt 1265: fprintf(stderr,
1.172 markus 1266: "You must change your password now and login again!\n");
1267: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1268: perror("passwd");
1269: } else {
1270: fprintf(stderr,
1271: "Password change required but no TTY available.\n");
1272: }
1273: exit(1);
1274: }
1275:
1276: static void
1.130 provos 1277: launch_login(struct passwd *pw, const char *hostname)
1278: {
1279: /* Launch login(1). */
1280:
1281: execl("/usr/bin/login", "login", "-h", hostname,
1282: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1283:
1284: /* Login couldn't be executed, die. */
1285:
1286: perror("login");
1287: exit(1);
1288: }
1289:
1.172 markus 1290: static void
1291: child_close_fds(void)
1292: {
1.266 markus 1293: extern AuthenticationConnection *auth_conn;
1294:
1295: if (auth_conn) {
1296: ssh_close_authentication_connection(auth_conn);
1297: auth_conn = NULL;
1298: }
1299:
1.172 markus 1300: if (packet_get_connection_in() == packet_get_connection_out())
1301: close(packet_get_connection_in());
1302: else {
1303: close(packet_get_connection_in());
1304: close(packet_get_connection_out());
1305: }
1306: /*
1307: * Close all descriptors related to channels. They will still remain
1308: * open in the parent.
1309: */
1310: /* XXX better use close-on-exec? -markus */
1311: channel_close_all();
1312:
1313: /*
1314: * Close any extra file descriptors. Note that there may still be
1315: * descriptors left by system functions. They will be closed later.
1316: */
1317: endpwent();
1318:
1319: /*
1.188 djm 1320: * Close any extra open file descriptors so that we don't have them
1.172 markus 1321: * hanging around in clients. Note that we want to do this after
1322: * initgroups, because at least on Solaris 2.3 it leaves file
1323: * descriptors open.
1324: */
1.258 djm 1325: closefrom(STDERR_FILENO + 1);
1.172 markus 1326: }
1327:
1.127 markus 1328: /*
1329: * Performs common processing for the child, such as setting up the
1330: * environment, closing extra file descriptors, setting the user and group
1331: * ids, and executing the command or shell.
1332: */
1.225 markus 1333: #define ARGV_MAX 10
1.127 markus 1334: void
1335: do_child(Session *s, const char *command)
1336: {
1337: extern char **environ;
1338: char **env;
1.225 markus 1339: char *argv[ARGV_MAX];
1.127 markus 1340: const char *shell, *shell0, *hostname = NULL;
1341: struct passwd *pw = s->pw;
1.239 djm 1342: int r = 0;
1.127 markus 1343:
1344: /* remove hostkey from the child's memory */
1345: destroy_sensitive_data();
1346:
1.172 markus 1347: /* Force a password change */
1348: if (s->authctxt->force_pwchange) {
1349: do_setusercontext(pw);
1350: child_close_fds();
1351: do_pwchange(s);
1352: exit(1);
1353: }
1354:
1.127 markus 1355: /* login(1) is only called if we execute the login shell */
1356: if (options.use_login && command != NULL)
1357: options.use_login = 0;
1358:
1359: /*
1360: * Login(1) does this as well, and it needs uid 0 for the "-h"
1361: * switch, so we let login(1) to this for us.
1362: */
1363: if (!options.use_login) {
1364: do_nologin(pw);
1365: do_setusercontext(pw);
1366: }
1367:
1368: /*
1369: * Get the shell from the password data. An empty shell field is
1370: * legal, and means /bin/sh.
1371: */
1372: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1373:
1374: /*
1375: * Make sure $SHELL points to the shell from the password file,
1376: * even if shell is overridden from login.conf
1377: */
1378: env = do_setup_env(s, shell);
1379:
1.127 markus 1380: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1381:
1.26 millert 1382: /* we have to stash the hostname before we close our socket. */
1383: if (options.use_login)
1.70 stevesk 1384: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1385: options.use_dns);
1.1 markus 1386: /*
1387: * Close the connection descriptors; note that this is the child, and
1388: * the server will still have the socket open, and it is important
1389: * that we do not shutdown it. Note that the descriptors cannot be
1390: * closed before building the environment, as we call
1391: * get_remote_ipaddr there.
1392: */
1.172 markus 1393: child_close_fds();
1.1 markus 1394:
1395: /*
1.125 deraadt 1396: * Must take new environment into use so that .ssh/rc,
1397: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1398: */
1399: environ = env;
1.170 jakob 1400:
1401: #ifdef KRB5
1402: /*
1403: * At this point, we check to see if AFS is active and if we have
1404: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1405: * if we can (and need to) extend the ticket into an AFS token. If
1406: * we don't do this, we run into potential problems if the user's
1407: * home directory is in AFS and it's not world-readable.
1408: */
1409:
1410: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1411: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1412: char cell[64];
1413:
1414: debug("Getting AFS token");
1415:
1416: k_setpag();
1417:
1418: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1419: krb5_afslog(s->authctxt->krb5_ctx,
1420: s->authctxt->krb5_fwd_ccache, cell, NULL);
1421:
1422: krb5_afslog_home(s->authctxt->krb5_ctx,
1423: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1424: }
1425: #endif
1.104 markus 1426:
1.188 djm 1427: /* Change current directory to the user's home directory. */
1.104 markus 1428: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1429: /* Suppress missing homedir warning for chroot case */
1430: r = login_getcapbool(lc, "requirehome", 0);
1.254 djm 1431: if (r || options.chroot_directory == NULL ||
1432: strcasecmp(options.chroot_directory, "none") == 0)
1.239 djm 1433: fprintf(stderr, "Could not chdir to home "
1434: "directory %s: %s\n", pw->pw_dir,
1435: strerror(errno));
1436: if (r)
1.104 markus 1437: exit(1);
1438: }
1.230 djm 1439:
1440: closefrom(STDERR_FILENO + 1);
1.1 markus 1441:
1.127 markus 1442: if (!options.use_login)
1443: do_rc_files(s, shell);
1.67 markus 1444:
1445: /* restore SIGPIPE for child */
1.217 stevesk 1446: signal(SIGPIPE, SIG_DFL);
1.67 markus 1447:
1.248 djm 1448: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1449: printf("This service allows sftp connections only.\n");
1450: fflush(NULL);
1451: exit(1);
1452: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1453: extern int optind, optreset;
1454: int i;
1455: char *p, *args;
1456:
1.246 stevesk 1457: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1458: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1459: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1460: if (i < ARGV_MAX - 1)
1461: argv[i++] = p;
1462: argv[i] = NULL;
1463: optind = optreset = 1;
1464: __progname = argv[0];
1.226 djm 1465: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1466: }
1.247 djm 1467:
1468: fflush(NULL);
1.225 markus 1469:
1.127 markus 1470: if (options.use_login) {
1.130 provos 1471: launch_login(pw, hostname);
1472: /* NEVERREACHED */
1.127 markus 1473: }
1474:
1475: /* Get the last component of the shell name. */
1476: if ((shell0 = strrchr(shell, '/')) != NULL)
1477: shell0++;
1478: else
1479: shell0 = shell;
1480:
1.1 markus 1481: /*
1482: * If we have no command, execute the shell. In this case, the shell
1483: * name to be passed in argv[0] is preceded by '-' to indicate that
1484: * this is a login shell.
1485: */
1486: if (!command) {
1.127 markus 1487: char argv0[256];
1.1 markus 1488:
1.127 markus 1489: /* Start the shell. Set initial character to '-'. */
1490: argv0[0] = '-';
1.1 markus 1491:
1.127 markus 1492: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1493: >= sizeof(argv0) - 1) {
1.127 markus 1494: errno = EINVAL;
1.1 markus 1495: perror(shell);
1496: exit(1);
1.127 markus 1497: }
1.1 markus 1498:
1.127 markus 1499: /* Execute the shell. */
1500: argv[0] = argv0;
1501: argv[1] = NULL;
1502: execve(shell, argv, env);
1503:
1504: /* Executing the shell failed. */
1505: perror(shell);
1506: exit(1);
1.1 markus 1507: }
1508: /*
1509: * Execute the command using the user's shell. This uses the -c
1510: * option to execute the command.
1511: */
1.127 markus 1512: argv[0] = (char *) shell0;
1.1 markus 1513: argv[1] = "-c";
1514: argv[2] = (char *) command;
1515: argv[3] = NULL;
1516: execve(shell, argv, env);
1517: perror(shell);
1518: exit(1);
1519: }
1520:
1.237 djm 1521: void
1522: session_unused(int id)
1523: {
1524: debug3("%s: session id %d unused", __func__, id);
1525: if (id >= options.max_sessions ||
1526: id >= sessions_nalloc) {
1527: fatal("%s: insane session id %d (max %d nalloc %d)",
1528: __func__, id, options.max_sessions, sessions_nalloc);
1529: }
1.270 tedu 1530: memset(&sessions[id], 0, sizeof(*sessions));
1.237 djm 1531: sessions[id].self = id;
1532: sessions[id].used = 0;
1533: sessions[id].chanid = -1;
1534: sessions[id].ptyfd = -1;
1535: sessions[id].ttyfd = -1;
1536: sessions[id].ptymaster = -1;
1537: sessions[id].x11_chanids = NULL;
1538: sessions[id].next_unused = sessions_first_unused;
1539: sessions_first_unused = id;
1540: }
1541:
1.1 markus 1542: Session *
1543: session_new(void)
1544: {
1.237 djm 1545: Session *s, *tmp;
1546:
1547: if (sessions_first_unused == -1) {
1548: if (sessions_nalloc >= options.max_sessions)
1549: return NULL;
1550: debug2("%s: allocate (allocated %d max %d)",
1551: __func__, sessions_nalloc, options.max_sessions);
1552: tmp = xrealloc(sessions, sessions_nalloc + 1,
1553: sizeof(*sessions));
1554: if (tmp == NULL) {
1555: error("%s: cannot allocate %d sessions",
1556: __func__, sessions_nalloc + 1);
1557: return NULL;
1558: }
1559: sessions = tmp;
1560: session_unused(sessions_nalloc++);
1561: }
1562:
1563: if (sessions_first_unused >= sessions_nalloc ||
1564: sessions_first_unused < 0) {
1565: fatal("%s: insane first_unused %d max %d nalloc %d",
1566: __func__, sessions_first_unused, options.max_sessions,
1567: sessions_nalloc);
1568: }
1569:
1570: s = &sessions[sessions_first_unused];
1571: if (s->used) {
1572: fatal("%s: session %d already used",
1573: __func__, sessions_first_unused);
1574: }
1575: sessions_first_unused = s->next_unused;
1576: s->used = 1;
1577: s->next_unused = -1;
1578: debug("session_new: session %d", s->self);
1579:
1580: return s;
1.1 markus 1581: }
1582:
1.94 itojun 1583: static void
1.1 markus 1584: session_dump(void)
1585: {
1586: int i;
1.237 djm 1587: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1588: Session *s = &sessions[i];
1.237 djm 1589:
1590: debug("dump: used %d next_unused %d session %d %p "
1591: "channel %d pid %ld",
1.1 markus 1592: s->used,
1.237 djm 1593: s->next_unused,
1.1 markus 1594: s->self,
1595: s,
1596: s->chanid,
1.137 mpech 1597: (long)s->pid);
1.1 markus 1598: }
1599: }
1600:
1.2 markus 1601: int
1.97 markus 1602: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1603: {
1604: Session *s = session_new();
1605: debug("session_open: channel %d", chanid);
1606: if (s == NULL) {
1607: error("no more sessions");
1608: return 0;
1609: }
1.97 markus 1610: s->authctxt = authctxt;
1611: s->pw = authctxt->pw;
1.167 djm 1612: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1613: fatal("no user for session %d", s->self);
1.2 markus 1614: debug("session_open: session %d: link with channel %d", s->self, chanid);
1615: s->chanid = chanid;
1616: return 1;
1617: }
1618:
1.130 provos 1619: Session *
1620: session_by_tty(char *tty)
1621: {
1622: int i;
1.237 djm 1623: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1624: Session *s = &sessions[i];
1625: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1626: debug("session_by_tty: session %d tty %s", i, tty);
1627: return s;
1628: }
1629: }
1630: debug("session_by_tty: unknown tty %.100s", tty);
1631: session_dump();
1632: return NULL;
1633: }
1634:
1.94 itojun 1635: static Session *
1.2 markus 1636: session_by_channel(int id)
1637: {
1638: int i;
1.237 djm 1639: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1640: Session *s = &sessions[i];
1641: if (s->used && s->chanid == id) {
1.237 djm 1642: debug("session_by_channel: session %d channel %d",
1643: i, id);
1.2 markus 1644: return s;
1645: }
1646: }
1647: debug("session_by_channel: unknown channel %d", id);
1648: session_dump();
1649: return NULL;
1650: }
1651:
1.94 itojun 1652: static Session *
1.184 djm 1653: session_by_x11_channel(int id)
1654: {
1655: int i, j;
1656:
1.237 djm 1657: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1658: Session *s = &sessions[i];
1659:
1660: if (s->x11_chanids == NULL || !s->used)
1661: continue;
1662: for (j = 0; s->x11_chanids[j] != -1; j++) {
1663: if (s->x11_chanids[j] == id) {
1664: debug("session_by_x11_channel: session %d "
1665: "channel %d", s->self, id);
1666: return s;
1667: }
1668: }
1669: }
1670: debug("session_by_x11_channel: unknown channel %d", id);
1671: session_dump();
1672: return NULL;
1673: }
1674:
1675: static Session *
1.2 markus 1676: session_by_pid(pid_t pid)
1677: {
1678: int i;
1.137 mpech 1679: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1680: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1681: Session *s = &sessions[i];
1682: if (s->used && s->pid == pid)
1683: return s;
1684: }
1.137 mpech 1685: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1686: session_dump();
1687: return NULL;
1688: }
1689:
1.94 itojun 1690: static int
1.2 markus 1691: session_window_change_req(Session *s)
1692: {
1693: s->col = packet_get_int();
1694: s->row = packet_get_int();
1695: s->xpixel = packet_get_int();
1696: s->ypixel = packet_get_int();
1.116 markus 1697: packet_check_eom();
1.2 markus 1698: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1699: return 1;
1700: }
1701:
1.94 itojun 1702: static int
1.2 markus 1703: session_pty_req(Session *s)
1704: {
1.45 markus 1705: u_int len;
1.72 stevesk 1706: int n_bytes;
1.132 markus 1707:
1.268 djm 1708: if (no_pty_flag || !options.permit_tty) {
1.86 markus 1709: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1710: return 0;
1.86 markus 1711: }
1712: if (s->ttyfd != -1) {
1713: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1714: return 0;
1.86 markus 1715: }
1716:
1.2 markus 1717: s->term = packet_get_string(&len);
1.86 markus 1718:
1719: if (compat20) {
1720: s->col = packet_get_int();
1721: s->row = packet_get_int();
1722: } else {
1723: s->row = packet_get_int();
1724: s->col = packet_get_int();
1725: }
1.2 markus 1726: s->xpixel = packet_get_int();
1727: s->ypixel = packet_get_int();
1728:
1729: if (strcmp(s->term, "") == 0) {
1.265 djm 1730: free(s->term);
1.2 markus 1731: s->term = NULL;
1732: }
1.86 markus 1733:
1.2 markus 1734: /* Allocate a pty and open it. */
1.86 markus 1735: debug("Allocating pty.");
1.237 djm 1736: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1737: sizeof(s->tty)))) {
1.265 djm 1738: free(s->term);
1.2 markus 1739: s->term = NULL;
1740: s->ptyfd = -1;
1741: s->ttyfd = -1;
1742: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1743: return 0;
1.2 markus 1744: }
1745: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1746:
1747: /* for SSH1 the tty modes length is not given */
1748: if (!compat20)
1749: n_bytes = packet_remaining();
1750: tty_parse_modes(s->ttyfd, &n_bytes);
1751:
1.130 provos 1752: if (!use_privsep)
1753: pty_setowner(s->pw, s->tty);
1.86 markus 1754:
1755: /* Set window size from the packet. */
1.2 markus 1756: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1757:
1.116 markus 1758: packet_check_eom();
1.9 markus 1759: session_proctitle(s);
1.2 markus 1760: return 1;
1761: }
1762:
1.94 itojun 1763: static int
1.7 markus 1764: session_subsystem_req(Session *s)
1765: {
1.105 markus 1766: struct stat st;
1.45 markus 1767: u_int len;
1.7 markus 1768: int success = 0;
1.267 djm 1769: char *prog, *cmd;
1.182 djm 1770: u_int i;
1.7 markus 1771:
1.267 djm 1772: s->subsys = packet_get_string(&len);
1.116 markus 1773: packet_check_eom();
1.267 djm 1774: debug2("subsystem request for %.100s by user %s", s->subsys,
1.255 djm 1775: s->pw->pw_name);
1.18 jakob 1776:
1777: for (i = 0; i < options.num_subsystems; i++) {
1.267 djm 1778: if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1779: prog = options.subsystem_command[i];
1780: cmd = options.subsystem_args[i];
1.249 dtucker 1781: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1782: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1783: debug("subsystem: %s", prog);
1.225 markus 1784: } else {
1.249 dtucker 1785: if (stat(prog, &st) < 0)
1786: debug("subsystem: cannot stat %s: %s",
1787: prog, strerror(errno));
1.225 markus 1788: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1789: debug("subsystem: exec() %s", cmd);
1.105 markus 1790: }
1.237 djm 1791: success = do_exec(s, cmd) == 0;
1.122 markus 1792: break;
1.18 jakob 1793: }
1794: }
1795:
1796: if (!success)
1.267 djm 1797: logit("subsystem request for %.100s by user %s failed, "
1798: "subsystem not found", s->subsys, s->pw->pw_name);
1.7 markus 1799:
1800: return success;
1801: }
1802:
1.94 itojun 1803: static int
1.7 markus 1804: session_x11_req(Session *s)
1805: {
1.81 markus 1806: int success;
1.7 markus 1807:
1.184 djm 1808: if (s->auth_proto != NULL || s->auth_data != NULL) {
1809: error("session_x11_req: session %d: "
1.190 stevesk 1810: "x11 forwarding already active", s->self);
1.184 djm 1811: return 0;
1812: }
1.7 markus 1813: s->single_connection = packet_get_char();
1814: s->auth_proto = packet_get_string(NULL);
1815: s->auth_data = packet_get_string(NULL);
1816: s->screen = packet_get_int();
1.116 markus 1817: packet_check_eom();
1.7 markus 1818:
1.81 markus 1819: success = session_setup_x11fwd(s);
1820: if (!success) {
1.265 djm 1821: free(s->auth_proto);
1822: free(s->auth_data);
1.84 markus 1823: s->auth_proto = NULL;
1824: s->auth_data = NULL;
1.7 markus 1825: }
1.81 markus 1826: return success;
1.7 markus 1827: }
1828:
1.94 itojun 1829: static int
1.19 markus 1830: session_shell_req(Session *s)
1831: {
1.116 markus 1832: packet_check_eom();
1.237 djm 1833: return do_exec(s, NULL) == 0;
1.19 markus 1834: }
1835:
1.94 itojun 1836: static int
1.19 markus 1837: session_exec_req(Session *s)
1838: {
1.237 djm 1839: u_int len, success;
1840:
1.19 markus 1841: char *command = packet_get_string(&len);
1.116 markus 1842: packet_check_eom();
1.237 djm 1843: success = do_exec(s, command) == 0;
1.265 djm 1844: free(command);
1.237 djm 1845: return success;
1.19 markus 1846: }
1847:
1.94 itojun 1848: static int
1.157 markus 1849: session_break_req(Session *s)
1850: {
1851:
1.175 deraadt 1852: packet_get_int(); /* ignored */
1.157 markus 1853: packet_check_eom();
1854:
1.259 djm 1855: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1856: return 0;
1857: return 1;
1858: }
1859:
1860: static int
1.173 djm 1861: session_env_req(Session *s)
1862: {
1863: char *name, *val;
1864: u_int name_len, val_len, i;
1865:
1.271 ! djm 1866: name = packet_get_cstring(&name_len);
! 1867: val = packet_get_cstring(&val_len);
1.173 djm 1868: packet_check_eom();
1869:
1870: /* Don't set too many environment variables */
1871: if (s->num_env > 128) {
1872: debug2("Ignoring env request %s: too many env vars", name);
1873: goto fail;
1874: }
1875:
1876: for (i = 0; i < options.num_accept_env; i++) {
1877: if (match_pattern(name, options.accept_env[i])) {
1878: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.201 djm 1879: s->env = xrealloc(s->env, s->num_env + 1,
1880: sizeof(*s->env));
1.173 djm 1881: s->env[s->num_env].name = name;
1882: s->env[s->num_env].val = val;
1883: s->num_env++;
1884: return (1);
1885: }
1886: }
1887: debug2("Ignoring env request %s: disallowed name", name);
1888:
1889: fail:
1.265 djm 1890: free(name);
1891: free(val);
1.173 djm 1892: return (0);
1893: }
1894:
1895: static int
1.43 markus 1896: session_auth_agent_req(Session *s)
1897: {
1898: static int called = 0;
1.116 markus 1899: packet_check_eom();
1.235 pyr 1900: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1901: debug("session_auth_agent_req: no_agent_forwarding_flag");
1902: return 0;
1903: }
1.43 markus 1904: if (called) {
1905: return 0;
1906: } else {
1907: called = 1;
1908: return auth_input_request_forwarding(s->pw);
1909: }
1910: }
1911:
1.123 markus 1912: int
1913: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1914: {
1915: int success = 0;
1916: Session *s;
1917:
1.123 markus 1918: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1919: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1920: c->self, rtype);
1921: return 0;
1922: }
1923: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1924:
1925: /*
1.64 markus 1926: * a session is in LARVAL state until a shell, a command
1927: * or a subsystem is executed
1.2 markus 1928: */
1929: if (c->type == SSH_CHANNEL_LARVAL) {
1930: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1931: success = session_shell_req(s);
1.2 markus 1932: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1933: success = session_exec_req(s);
1.2 markus 1934: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1935: success = session_pty_req(s);
1.7 markus 1936: } else if (strcmp(rtype, "x11-req") == 0) {
1937: success = session_x11_req(s);
1.43 markus 1938: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1939: success = session_auth_agent_req(s);
1.7 markus 1940: } else if (strcmp(rtype, "subsystem") == 0) {
1941: success = session_subsystem_req(s);
1.173 djm 1942: } else if (strcmp(rtype, "env") == 0) {
1943: success = session_env_req(s);
1.2 markus 1944: }
1945: }
1946: if (strcmp(rtype, "window-change") == 0) {
1947: success = session_window_change_req(s);
1.177 djm 1948: } else if (strcmp(rtype, "break") == 0) {
1949: success = session_break_req(s);
1.2 markus 1950: }
1.177 djm 1951:
1.123 markus 1952: return success;
1.2 markus 1953: }
1954:
1955: void
1.256 djm 1956: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1957: int is_tty)
1.2 markus 1958: {
1959: if (!compat20)
1960: fatal("session_set_fds: called for proto != 2.0");
1961: /*
1962: * now that have a child and a pipe to the child,
1963: * we can activate our channel and register the fd's
1964: */
1965: if (s->chanid == -1)
1966: fatal("no channel for session %d", s->self);
1967: channel_set_fds(s->chanid,
1968: fdout, fdin, fderr,
1.256 djm 1969: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1970: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1971: }
1972:
1.85 markus 1973: /*
1974: * Function to perform pty cleanup. Also called if we get aborted abnormally
1975: * (e.g., due to a dropped connection).
1976: */
1.130 provos 1977: void
1.165 markus 1978: session_pty_cleanup2(Session *s)
1.1 markus 1979: {
1.85 markus 1980: if (s == NULL) {
1981: error("session_pty_cleanup: no session");
1982: return;
1983: }
1984: if (s->ttyfd == -1)
1.1 markus 1985: return;
1986:
1.54 stevesk 1987: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1988:
1989: /* Record that the user has logged out. */
1.85 markus 1990: if (s->pid != 0)
1991: record_logout(s->pid, s->tty);
1.1 markus 1992:
1993: /* Release the pseudo-tty. */
1.130 provos 1994: if (getuid() == 0)
1995: pty_release(s->tty);
1.1 markus 1996:
1997: /*
1998: * Close the server side of the socket pairs. We must do this after
1999: * the pty cleanup, so that another process doesn't get this pty
2000: * while we're still cleaning up.
2001: */
1.237 djm 2002: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2003: error("close(s->ptymaster/%d): %s",
2004: s->ptymaster, strerror(errno));
1.108 markus 2005:
2006: /* unlink pty from session */
2007: s->ttyfd = -1;
1.2 markus 2008: }
2009:
1.130 provos 2010: void
1.165 markus 2011: session_pty_cleanup(Session *s)
1.130 provos 2012: {
1.165 markus 2013: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 2014: }
2015:
1.147 markus 2016: static char *
2017: sig2name(int sig)
2018: {
2019: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2020: SSH_SIG(ABRT);
2021: SSH_SIG(ALRM);
2022: SSH_SIG(FPE);
2023: SSH_SIG(HUP);
2024: SSH_SIG(ILL);
2025: SSH_SIG(INT);
2026: SSH_SIG(KILL);
2027: SSH_SIG(PIPE);
2028: SSH_SIG(QUIT);
2029: SSH_SIG(SEGV);
2030: SSH_SIG(TERM);
2031: SSH_SIG(USR1);
2032: SSH_SIG(USR2);
2033: #undef SSH_SIG
2034: return "SIG@openssh.com";
2035: }
2036:
1.94 itojun 2037: static void
1.184 djm 2038: session_close_x11(int id)
2039: {
2040: Channel *c;
2041:
1.189 markus 2042: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2043: debug("session_close_x11: x11 channel %d missing", id);
2044: } else {
2045: /* Detach X11 listener */
2046: debug("session_close_x11: detach x11 channel %d", id);
2047: channel_cancel_cleanup(id);
2048: if (c->ostate != CHAN_OUTPUT_CLOSED)
2049: chan_mark_dead(c);
2050: }
2051: }
2052:
2053: static void
2054: session_close_single_x11(int id, void *arg)
2055: {
2056: Session *s;
2057: u_int i;
2058:
2059: debug3("session_close_single_x11: channel %d", id);
2060: channel_cancel_cleanup(id);
1.221 stevesk 2061: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2062: fatal("session_close_single_x11: no x11 channel %d", id);
2063: for (i = 0; s->x11_chanids[i] != -1; i++) {
2064: debug("session_close_single_x11: session %d: "
2065: "closing channel %d", s->self, s->x11_chanids[i]);
2066: /*
2067: * The channel "id" is already closing, but make sure we
2068: * close all of its siblings.
2069: */
2070: if (s->x11_chanids[i] != id)
2071: session_close_x11(s->x11_chanids[i]);
2072: }
1.265 djm 2073: free(s->x11_chanids);
1.184 djm 2074: s->x11_chanids = NULL;
1.265 djm 2075: free(s->display);
2076: s->display = NULL;
2077: free(s->auth_proto);
2078: s->auth_proto = NULL;
2079: free(s->auth_data);
2080: s->auth_data = NULL;
2081: free(s->auth_display);
2082: s->auth_display = NULL;
1.184 djm 2083: }
2084:
2085: static void
1.2 markus 2086: session_exit_message(Session *s, int status)
2087: {
2088: Channel *c;
1.124 markus 2089:
2090: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2091: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2092: s->self, s->chanid);
1.137 mpech 2093: debug("session_exit_message: session %d channel %d pid %ld",
2094: s->self, s->chanid, (long)s->pid);
1.2 markus 2095:
2096: if (WIFEXITED(status)) {
1.124 markus 2097: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2098: packet_put_int(WEXITSTATUS(status));
2099: packet_send();
2100: } else if (WIFSIGNALED(status)) {
1.124 markus 2101: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2102: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2103: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2104: packet_put_cstring("");
2105: packet_put_cstring("");
2106: packet_send();
2107: } else {
2108: /* Some weird exit cause. Just exit. */
2109: packet_disconnect("wait returned status %04x.", status);
2110: }
2111:
2112: /* disconnect channel */
2113: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2114:
2115: /*
2116: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2117: * the channel gets EOF. The session will be then be closed
1.187 djm 2118: * by session_close_by_channel when the childs close their fds.
2119: */
2120: channel_register_cleanup(c->self, session_close_by_channel, 1);
2121:
1.5 markus 2122: /*
2123: * emulate a write failure with 'chan_write_failed', nobody will be
2124: * interested in data we write.
2125: * Note that we must not call 'chan_read_failed', since there could
2126: * be some more data waiting in the pipe.
2127: */
1.8 markus 2128: if (c->ostate != CHAN_OUTPUT_CLOSED)
2129: chan_write_failed(c);
1.2 markus 2130: }
2131:
1.130 provos 2132: void
1.85 markus 2133: session_close(Session *s)
1.2 markus 2134: {
1.182 djm 2135: u_int i;
1.173 djm 2136:
1.137 mpech 2137: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165 markus 2138: if (s->ttyfd != -1)
1.85 markus 2139: session_pty_cleanup(s);
1.265 djm 2140: free(s->term);
2141: free(s->display);
2142: free(s->x11_chanids);
2143: free(s->auth_display);
2144: free(s->auth_data);
2145: free(s->auth_proto);
1.267 djm 2146: free(s->subsys);
1.219 djm 2147: if (s->env != NULL) {
2148: for (i = 0; i < s->num_env; i++) {
1.265 djm 2149: free(s->env[i].name);
2150: free(s->env[i].val);
1.219 djm 2151: }
1.265 djm 2152: free(s->env);
1.173 djm 2153: }
1.9 markus 2154: session_proctitle(s);
1.237 djm 2155: session_unused(s->self);
1.2 markus 2156: }
2157:
2158: void
2159: session_close_by_pid(pid_t pid, int status)
2160: {
2161: Session *s = session_by_pid(pid);
2162: if (s == NULL) {
1.137 mpech 2163: debug("session_close_by_pid: no session for pid %ld",
2164: (long)pid);
1.2 markus 2165: return;
2166: }
2167: if (s->chanid != -1)
2168: session_exit_message(s, status);
1.187 djm 2169: if (s->ttyfd != -1)
2170: session_pty_cleanup(s);
1.197 djm 2171: s->pid = 0;
1.98 markus 2172: }
2173:
1.2 markus 2174: /*
2175: * this is called when a channel dies before
2176: * the session 'child' itself dies
2177: */
2178: void
2179: session_close_by_channel(int id, void *arg)
2180: {
2181: Session *s = session_by_channel(id);
1.187 djm 2182: u_int i;
1.184 djm 2183:
1.2 markus 2184: if (s == NULL) {
1.107 markus 2185: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2186: return;
2187: }
1.137 mpech 2188: debug("session_close_by_channel: channel %d child %ld",
2189: id, (long)s->pid);
1.107 markus 2190: if (s->pid != 0) {
2191: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2192: /*
2193: * delay detach of session, but release pty, since
2194: * the fd's to the child are already closed
2195: */
1.165 markus 2196: if (s->ttyfd != -1)
1.108 markus 2197: session_pty_cleanup(s);
1.107 markus 2198: return;
2199: }
2200: /* detach by removing callback */
1.2 markus 2201: channel_cancel_cleanup(s->chanid);
1.187 djm 2202:
2203: /* Close any X11 listeners associated with this session */
2204: if (s->x11_chanids != NULL) {
2205: for (i = 0; s->x11_chanids[i] != -1; i++) {
2206: session_close_x11(s->x11_chanids[i]);
2207: s->x11_chanids[i] = -1;
2208: }
2209: }
2210:
1.2 markus 2211: s->chanid = -1;
1.106 markus 2212: session_close(s);
2213: }
2214:
2215: void
1.130 provos 2216: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2217: {
2218: int i;
1.237 djm 2219: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2220: Session *s = &sessions[i];
1.130 provos 2221: if (s->used) {
2222: if (closefunc != NULL)
2223: closefunc(s);
2224: else
2225: session_close(s);
2226: }
1.2 markus 2227: }
1.9 markus 2228: }
2229:
1.94 itojun 2230: static char *
1.9 markus 2231: session_tty_list(void)
2232: {
2233: static char buf[1024];
2234: int i;
2235: buf[0] = '\0';
1.237 djm 2236: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2237: Session *s = &sessions[i];
2238: if (s->used && s->ttyfd != -1) {
2239: if (buf[0] != '\0')
2240: strlcat(buf, ",", sizeof buf);
2241: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2242: }
2243: }
2244: if (buf[0] == '\0')
2245: strlcpy(buf, "notty", sizeof buf);
2246: return buf;
2247: }
2248:
2249: void
2250: session_proctitle(Session *s)
2251: {
2252: if (s->pw == NULL)
2253: error("no user for session %d", s->self);
2254: else
2255: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2256: }
2257:
2258: int
2259: session_setup_x11fwd(Session *s)
2260: {
2261: struct stat st;
1.109 stevesk 2262: char display[512], auth_display[512];
2263: char hostname[MAXHOSTNAMELEN];
1.184 djm 2264: u_int i;
1.81 markus 2265:
2266: if (no_x11_forwarding_flag) {
2267: packet_send_debug("X11 forwarding disabled in user configuration file.");
2268: return 0;
2269: }
2270: if (!options.x11_forwarding) {
2271: debug("X11 forwarding disabled in server configuration file.");
2272: return 0;
2273: }
2274: if (!options.xauth_location ||
2275: (stat(options.xauth_location, &st) == -1)) {
2276: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2277: return 0;
2278: }
2279: if (options.use_login) {
2280: packet_send_debug("X11 forwarding disabled; "
2281: "not compatible with UseLogin=yes.");
1.81 markus 2282: return 0;
2283: }
1.87 markus 2284: if (s->display != NULL) {
1.81 markus 2285: debug("X11 display already set.");
2286: return 0;
2287: }
1.140 deraadt 2288: if (x11_create_display_inet(options.x11_display_offset,
2289: options.x11_use_localhost, s->single_connection,
1.184 djm 2290: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2291: debug("x11_create_display_inet failed.");
1.81 markus 2292: return 0;
1.184 djm 2293: }
2294: for (i = 0; s->x11_chanids[i] != -1; i++) {
2295: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2296: session_close_single_x11, 0);
1.81 markus 2297: }
1.109 stevesk 2298:
2299: /* Set up a suitable value for the DISPLAY variable. */
2300: if (gethostname(hostname, sizeof(hostname)) < 0)
2301: fatal("gethostname: %.100s", strerror(errno));
2302: /*
2303: * auth_display must be used as the displayname when the
2304: * authorization entry is added with xauth(1). This will be
2305: * different than the DISPLAY string for localhost displays.
2306: */
1.119 stevesk 2307: if (options.x11_use_localhost) {
1.140 deraadt 2308: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2309: s->display_number, s->screen);
1.140 deraadt 2310: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2311: s->display_number, s->screen);
1.109 stevesk 2312: s->display = xstrdup(display);
1.118 stevesk 2313: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2314: } else {
1.140 deraadt 2315: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2316: s->display_number, s->screen);
2317: s->display = xstrdup(display);
1.118 stevesk 2318: s->auth_display = xstrdup(display);
1.109 stevesk 2319: }
2320:
1.81 markus 2321: return 1;
1.2 markus 2322: }
2323:
1.94 itojun 2324: static void
1.49 markus 2325: do_authenticated2(Authctxt *authctxt)
1.2 markus 2326: {
1.97 markus 2327: server_loop2(authctxt);
1.165 markus 2328: }
2329:
2330: void
2331: do_cleanup(Authctxt *authctxt)
2332: {
2333: static int called = 0;
2334:
2335: debug("do_cleanup");
2336:
2337: /* no cleanup if we're in the child for login shell */
2338: if (is_child)
2339: return;
2340:
2341: /* avoid double cleanup */
2342: if (called)
2343: return;
2344: called = 1;
2345:
1.218 markus 2346: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2347: return;
2348: #ifdef KRB5
2349: if (options.kerberos_ticket_cleanup &&
2350: authctxt->krb5_ctx)
2351: krb5_cleanup_proc(authctxt);
1.161 markus 2352: #endif
1.165 markus 2353:
2354: #ifdef GSSAPI
2355: if (compat20 && options.gss_cleanup_creds)
2356: ssh_gssapi_cleanup_creds();
2357: #endif
2358:
2359: /* remove agent socket */
2360: auth_sock_cleanup_proc(authctxt->pw);
2361:
2362: /*
2363: * Cleanup ptys/utmp only if privsep is disabled,
2364: * or if running in monitor.
2365: */
2366: if (!use_privsep || mm_is_monitor())
2367: session_destroy_all(session_pty_cleanup2);
1.1 markus 2368: }
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