Annotation of src/usr.bin/ssh/session.c, Revision 1.280.2.1
1.280.2.1! djm 1: /* $OpenBSD: session.c,v 1.280 2016/02/16 03:37:48 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>
1.236 djm 41: #include <sys/queue.h>
1.192 stevesk 42:
1.280.2.1! djm 43: #include <ctype.h>
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>
1.272 djm 48: #include <netdb.h>
1.192 stevesk 49: #include <paths.h>
1.206 stevesk 50: #include <pwd.h>
1.195 stevesk 51: #include <signal.h>
1.215 stevesk 52: #include <stdio.h>
1.214 stevesk 53: #include <stdlib.h>
1.212 stevesk 54: #include <string.h>
1.211 stevesk 55: #include <unistd.h>
1.277 deraadt 56: #include <limits.h>
1.1 markus 57:
1.216 deraadt 58: #include "xmalloc.h"
1.51 markus 59: #include "ssh.h"
60: #include "ssh1.h"
61: #include "ssh2.h"
1.59 djm 62: #include "sshpty.h"
1.1 markus 63: #include "packet.h"
64: #include "buffer.h"
1.173 djm 65: #include "match.h"
1.1 markus 66: #include "uidswap.h"
67: #include "compat.h"
1.78 markus 68: #include "channels.h"
1.216 deraadt 69: #include "key.h"
70: #include "cipher.h"
71: #include "kex.h"
72: #include "hostfile.h"
1.2 markus 73: #include "auth.h"
1.19 markus 74: #include "auth-options.h"
1.266 markus 75: #include "authfd.h"
1.50 markus 76: #include "pathnames.h"
1.51 markus 77: #include "log.h"
1.274 millert 78: #include "misc.h"
1.51 markus 79: #include "servconf.h"
1.59 djm 80: #include "sshlogin.h"
1.51 markus 81: #include "serverloop.h"
82: #include "canohost.h"
1.55 itojun 83: #include "session.h"
1.216 deraadt 84: #ifdef GSSAPI
85: #include "ssh-gss.h"
86: #endif
1.130 provos 87: #include "monitor_wrap.h"
1.225 markus 88: #include "sftp.h"
1.171 markus 89:
90: #ifdef KRB5
91: #include <kafs.h>
1.161 markus 92: #endif
93:
1.242 djm 94: #define IS_INTERNAL_SFTP(c) \
95: (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
96: (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
97: c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
98: c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
99:
1.1 markus 100: /* func */
101:
102: Session *session_new(void);
1.256 djm 103: void session_set_fds(Session *, int, int, int, int, int);
1.165 markus 104: void session_pty_cleanup(Session *);
1.94 itojun 105: void session_proctitle(Session *);
106: int session_setup_x11fwd(Session *);
1.237 djm 107: int do_exec_pty(Session *, const char *);
108: int do_exec_no_pty(Session *, const char *);
109: int do_exec(Session *, const char *);
1.94 itojun 110: void do_login(Session *, const char *);
111: void do_child(Session *, const char *);
1.73 djm 112: void do_motd(void);
1.94 itojun 113: int check_quietlogin(Session *, const char *);
1.1 markus 114:
1.94 itojun 115: static void do_authenticated1(Authctxt *);
116: static void do_authenticated2(Authctxt *);
117:
118: static int session_pty_req(Session *);
1.65 markus 119:
1.1 markus 120: /* import */
121: extern ServerOptions options;
122: extern char *__progname;
123: extern int log_stderr;
124: extern int debug_flag;
1.45 markus 125: extern u_int utmp_len;
1.21 markus 126: extern int startup_pipe;
1.74 markus 127: extern void destroy_sensitive_data(void);
1.179 dtucker 128: extern Buffer loginmsg;
1.21 markus 129:
1.34 markus 130: /* original command from peer. */
1.92 markus 131: const char *original_command = NULL;
1.34 markus 132:
1.1 markus 133: /* data */
1.237 djm 134: static int sessions_first_unused = -1;
135: static int sessions_nalloc = 0;
136: static Session *sessions = NULL;
1.1 markus 137:
1.248 djm 138: #define SUBSYSTEM_NONE 0
139: #define SUBSYSTEM_EXT 1
140: #define SUBSYSTEM_INT_SFTP 2
141: #define SUBSYSTEM_INT_SFTP_ERROR 3
1.225 markus 142:
1.129 provos 143: login_cap_t *lc;
1.28 millert 144:
1.165 markus 145: static int is_child = 0;
1.279 djm 146: static int in_chroot = 0;
1.165 markus 147:
1.136 markus 148: /* Name and directory of socket for authentication agent forwarding. */
149: static char *auth_sock_name = NULL;
150: static char *auth_sock_dir = NULL;
151:
152: /* removes the agent forwarding socket */
153:
154: static void
1.165 markus 155: auth_sock_cleanup_proc(struct passwd *pw)
1.136 markus 156: {
157: if (auth_sock_name != NULL) {
158: temporarily_use_uid(pw);
159: unlink(auth_sock_name);
160: rmdir(auth_sock_dir);
161: auth_sock_name = NULL;
162: restore_uid();
163: }
164: }
165:
166: static int
167: auth_input_request_forwarding(struct passwd * pw)
168: {
169: Channel *nc;
1.237 djm 170: int sock = -1;
1.136 markus 171:
172: if (auth_sock_name != NULL) {
173: error("authentication forwarding requested twice.");
174: return 0;
175: }
176:
177: /* Temporarily drop privileged uid for mkdir/bind. */
178: temporarily_use_uid(pw);
179:
180: /* Allocate a buffer for the socket name, and format the name. */
1.237 djm 181: auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
1.136 markus 182:
183: /* Create private directory for socket */
184: if (mkdtemp(auth_sock_dir) == NULL) {
185: packet_send_debug("Agent forwarding disabled: "
186: "mkdtemp() failed: %.100s", strerror(errno));
187: restore_uid();
1.265 djm 188: free(auth_sock_dir);
1.136 markus 189: auth_sock_dir = NULL;
1.237 djm 190: goto authsock_err;
1.136 markus 191: }
1.237 djm 192:
193: xasprintf(&auth_sock_name, "%s/agent.%ld",
194: auth_sock_dir, (long) getpid());
1.136 markus 195:
1.274 millert 196: /* Start a Unix listener on auth_sock_name. */
197: sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0);
1.136 markus 198:
199: /* Restore the privileged uid. */
200: restore_uid();
201:
1.274 millert 202: /* Check for socket/bind/listen failure. */
203: if (sock < 0)
1.237 djm 204: goto authsock_err;
1.136 markus 205:
206: /* Allocate a channel for the authentication agent socket. */
207: nc = channel_new("auth socket",
208: SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
209: CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1.156 markus 210: 0, "auth socket", 1);
1.245 djm 211: nc->path = xstrdup(auth_sock_name);
1.136 markus 212: return 1;
1.237 djm 213:
214: authsock_err:
1.265 djm 215: free(auth_sock_name);
1.237 djm 216: if (auth_sock_dir != NULL) {
217: rmdir(auth_sock_dir);
1.265 djm 218: free(auth_sock_dir);
1.237 djm 219: }
220: if (sock != -1)
221: close(sock);
222: auth_sock_name = NULL;
223: auth_sock_dir = NULL;
224: return 0;
1.136 markus 225: }
226:
1.179 dtucker 227: static void
228: display_loginmsg(void)
229: {
1.183 djm 230: if (buffer_len(&loginmsg) > 0) {
231: buffer_append(&loginmsg, "\0", 1);
232: printf("%s", (char *)buffer_ptr(&loginmsg));
233: buffer_clear(&loginmsg);
234: }
1.179 dtucker 235: }
1.136 markus 236:
1.65 markus 237: void
238: do_authenticated(Authctxt *authctxt)
239: {
1.153 markus 240: setproctitle("%s", authctxt->pw->pw_name);
241:
1.65 markus 242: /* setup the channel layer */
1.274 millert 243: /* XXX - streamlocal? */
1.261 djm 244: if (no_port_forwarding_flag ||
245: (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
246: channel_disable_adm_local_opens();
247: else
1.65 markus 248: channel_permit_all_opens();
1.252 dtucker 249:
250: auth_debug_send();
1.65 markus 251:
252: if (compat20)
253: do_authenticated2(authctxt);
254: else
255: do_authenticated1(authctxt);
1.79 markus 256:
1.165 markus 257: do_cleanup(authctxt);
1.65 markus 258: }
259:
1.280.2.1! djm 260: /* Check untrusted xauth strings for metacharacters */
! 261: static int
! 262: xauth_valid_string(const char *s)
! 263: {
! 264: size_t i;
! 265:
! 266: for (i = 0; s[i] != '\0'; i++) {
! 267: if (!isalnum((u_char)s[i]) &&
! 268: s[i] != '.' && s[i] != ':' && s[i] != '/' &&
! 269: s[i] != '-' && s[i] != '_')
! 270: return 0;
! 271: }
! 272: return 1;
! 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();
1.280.2.1! djm 348: if (xauth_valid_string(s->auth_proto) &&
! 349: xauth_valid_string(s->auth_data))
! 350: success = session_setup_x11fwd(s);
! 351: else {
! 352: success = 0;
! 353: error("Invalid X11 forwarding data");
! 354: }
1.81 markus 355: if (!success) {
1.265 djm 356: free(s->auth_proto);
357: free(s->auth_data);
1.84 markus 358: s->auth_proto = NULL;
359: s->auth_data = NULL;
1.1 markus 360: }
361: break;
362:
363: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1.235 pyr 364: if (!options.allow_agent_forwarding ||
365: no_agent_forwarding_flag || compat13) {
1.1 markus 366: debug("Authentication agent forwarding not permitted for this authentication.");
367: break;
368: }
369: debug("Received authentication agent forwarding request.");
1.65 markus 370: success = auth_input_request_forwarding(s->pw);
1.1 markus 371: break;
372:
373: case SSH_CMSG_PORT_FORWARD_REQUEST:
374: if (no_port_forwarding_flag) {
375: debug("Port forwarding not permitted for this authentication.");
1.39 markus 376: break;
377: }
1.261 djm 378: if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
1.39 markus 379: debug("Port forwarding not permitted.");
1.1 markus 380: break;
381: }
382: debug("Received TCP/IP port forwarding request.");
1.208 markus 383: if (channel_input_port_forward_request(s->pw->pw_uid == 0,
1.274 millert 384: &options.fwd_opts) < 0) {
1.208 markus 385: debug("Port forwarding failed.");
386: break;
387: }
1.1 markus 388: success = 1;
389: break;
390:
391: case SSH_CMSG_MAX_PACKET_SIZE:
392: if (packet_set_maxsize(packet_get_int()) > 0)
393: success = 1;
394: break;
395:
396: case SSH_CMSG_EXEC_SHELL:
397: case SSH_CMSG_EXEC_CMD:
398: if (type == SSH_CMSG_EXEC_CMD) {
399: command = packet_get_string(&dlen);
400: debug("Exec command '%.500s'", command);
1.237 djm 401: if (do_exec(s, command) != 0)
402: packet_disconnect(
403: "command execution failed");
1.265 djm 404: free(command);
1.1 markus 405: } else {
1.237 djm 406: if (do_exec(s, NULL) != 0)
407: packet_disconnect(
408: "shell execution failed");
1.1 markus 409: }
1.116 markus 410: packet_check_eom();
1.82 markus 411: session_close(s);
1.1 markus 412: return;
413:
414: default:
415: /*
416: * Any unknown messages in this phase are ignored,
417: * and a failure message is returned.
418: */
1.155 itojun 419: logit("Unknown packet type received after authentication: %d", type);
1.1 markus 420: }
421: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
422: packet_send();
423: packet_write_wait();
424:
425: /* Enable compression now that we have replied if appropriate. */
426: if (enable_compression_after_reply) {
427: enable_compression_after_reply = 0;
428: packet_start_compression(compression_level);
429: }
430: }
431: }
432:
1.269 dtucker 433: #define USE_PIPES 1
1.1 markus 434: /*
435: * This is called to fork and execute a command when we have no tty. This
436: * will call do_child from the child, and server_loop from the parent after
437: * setting up file descriptors and such.
438: */
1.237 djm 439: int
1.63 markus 440: do_exec_no_pty(Session *s, const char *command)
1.1 markus 441: {
1.137 mpech 442: pid_t pid;
1.238 markus 443: #ifdef USE_PIPES
444: int pin[2], pout[2], perr[2];
445:
1.253 djm 446: if (s == NULL)
447: fatal("do_exec_no_pty: no session");
448:
1.238 markus 449: /* Allocate pipes for communicating with the program. */
450: if (pipe(pin) < 0) {
451: error("%s: pipe in: %.100s", __func__, strerror(errno));
452: return -1;
453: }
454: if (pipe(pout) < 0) {
455: error("%s: pipe out: %.100s", __func__, strerror(errno));
456: close(pin[0]);
457: close(pin[1]);
458: return -1;
459: }
1.256 djm 460: if (pipe(perr) < 0) {
461: error("%s: pipe err: %.100s", __func__,
462: strerror(errno));
463: close(pin[0]);
464: close(pin[1]);
465: close(pout[0]);
466: close(pout[1]);
467: return -1;
1.238 markus 468: }
469: #else
1.237 djm 470: int inout[2], err[2];
1.1 markus 471:
1.253 djm 472: if (s == NULL)
473: fatal("do_exec_no_pty: no session");
474:
1.1 markus 475: /* Uses socket pairs to communicate with the program. */
1.237 djm 476: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
477: error("%s: socketpair #1: %.100s", __func__, strerror(errno));
478: return -1;
479: }
1.256 djm 480: if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
481: error("%s: socketpair #2: %.100s", __func__,
482: strerror(errno));
483: close(inout[0]);
484: close(inout[1]);
485: return -1;
1.237 djm 486: }
1.238 markus 487: #endif
1.237 djm 488:
1.9 markus 489: session_proctitle(s);
1.1 markus 490:
491: /* Fork the child. */
1.237 djm 492: switch ((pid = fork())) {
493: case -1:
494: error("%s: fork: %.100s", __func__, strerror(errno));
1.238 markus 495: #ifdef USE_PIPES
496: close(pin[0]);
497: close(pin[1]);
498: close(pout[0]);
499: close(pout[1]);
1.256 djm 500: close(perr[0]);
1.238 markus 501: close(perr[1]);
502: #else
1.237 djm 503: close(inout[0]);
504: close(inout[1]);
505: close(err[0]);
1.256 djm 506: close(err[1]);
1.238 markus 507: #endif
1.237 djm 508: return -1;
509: case 0:
1.165 markus 510: is_child = 1;
1.144 markus 511:
1.1 markus 512: /* Child. Reinitialize the log since the pid has changed. */
1.237 djm 513: log_init(__progname, options.log_level,
514: options.log_facility, log_stderr);
1.1 markus 515:
516: /*
517: * Create a new session and process group since the 4.4BSD
518: * setlogin() affects the entire process group.
519: */
520: if (setsid() < 0)
521: error("setsid failed: %.100s", strerror(errno));
522:
1.238 markus 523: #ifdef USE_PIPES
524: /*
525: * Redirect stdin. We close the parent side of the socket
526: * pair, and make the child side the standard input.
527: */
528: close(pin[1]);
529: if (dup2(pin[0], 0) < 0)
530: perror("dup2 stdin");
531: close(pin[0]);
532:
533: /* Redirect stdout. */
534: close(pout[0]);
535: if (dup2(pout[1], 1) < 0)
536: perror("dup2 stdout");
537: close(pout[1]);
538:
539: /* Redirect stderr. */
1.256 djm 540: close(perr[0]);
1.238 markus 541: if (dup2(perr[1], 2) < 0)
542: perror("dup2 stderr");
543: close(perr[1]);
544: #else
1.1 markus 545: /*
546: * Redirect stdin, stdout, and stderr. Stdin and stdout will
547: * use the same socket, as some programs (particularly rdist)
548: * seem to depend on it.
549: */
550: close(inout[1]);
1.256 djm 551: close(err[1]);
1.1 markus 552: if (dup2(inout[0], 0) < 0) /* stdin */
553: perror("dup2 stdin");
1.237 djm 554: if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
1.1 markus 555: perror("dup2 stdout");
1.238 markus 556: close(inout[0]);
1.1 markus 557: if (dup2(err[0], 2) < 0) /* stderr */
558: perror("dup2 stderr");
1.238 markus 559: close(err[0]);
560: #endif
1.1 markus 561:
562: /* Do processing for the child (exec command etc). */
1.60 markus 563: do_child(s, command);
1.1 markus 564: /* NOTREACHED */
1.237 djm 565: default:
566: break;
1.1 markus 567: }
1.237 djm 568:
1.1 markus 569: s->pid = pid;
1.47 markus 570: /* Set interactive/non-interactive mode. */
1.257 djm 571: packet_set_interactive(s->display != NULL,
572: options.ip_qos_interactive, options.ip_qos_bulk);
1.1 markus 573:
1.238 markus 574: #ifdef USE_PIPES
575: /* We are the parent. Close the child sides of the pipes. */
576: close(pin[0]);
577: close(pout[1]);
578: close(perr[1]);
579:
580: if (compat20) {
1.256 djm 581: session_set_fds(s, pin[1], pout[0], perr[0],
582: s->is_subsystem, 0);
1.238 markus 583: } else {
584: /* Enter the interactive session. */
585: server_loop(pid, pin[1], pout[0], perr[0]);
586: /* server_loop has closed pin[1], pout[0], and perr[0]. */
587: }
588: #else
1.1 markus 589: /* We are the parent. Close the child sides of the socket pairs. */
590: close(inout[0]);
591: close(err[0]);
592:
593: /*
594: * Enter the interactive session. Note: server_loop must be able to
595: * handle the case that fdin and fdout are the same.
596: */
1.2 markus 597: if (compat20) {
1.256 djm 598: session_set_fds(s, inout[1], inout[1], err[1],
599: s->is_subsystem, 0);
1.2 markus 600: } else {
601: server_loop(pid, inout[1], inout[1], err[1]);
602: /* server_loop has closed inout[1] and err[1]. */
603: }
1.238 markus 604: #endif
1.237 djm 605: return 0;
1.1 markus 606: }
607:
608: /*
609: * This is called to fork and execute a command when we have a tty. This
610: * will call do_child from the child, and server_loop from the parent after
611: * setting up file descriptors, controlling tty, updating wtmp, utmp,
612: * lastlog, and other such operations.
613: */
1.237 djm 614: int
1.63 markus 615: do_exec_pty(Session *s, const char *command)
1.1 markus 616: {
617: int fdout, ptyfd, ttyfd, ptymaster;
618: pid_t pid;
619:
620: if (s == NULL)
621: fatal("do_exec_pty: no session");
622: ptyfd = s->ptyfd;
623: ttyfd = s->ttyfd;
624:
1.237 djm 625: /*
626: * Create another descriptor of the pty master side for use as the
627: * standard input. We could use the original descriptor, but this
628: * simplifies code in server_loop. The descriptor is bidirectional.
629: * Do this before forking (and cleanup in the child) so as to
630: * detect and gracefully fail out-of-fd conditions.
631: */
632: if ((fdout = dup(ptyfd)) < 0) {
633: error("%s: dup #1: %s", __func__, strerror(errno));
634: close(ttyfd);
635: close(ptyfd);
636: return -1;
637: }
638: /* we keep a reference to the pty master */
639: if ((ptymaster = dup(ptyfd)) < 0) {
640: error("%s: dup #2: %s", __func__, strerror(errno));
641: close(ttyfd);
642: close(ptyfd);
643: close(fdout);
644: return -1;
645: }
646:
1.1 markus 647: /* Fork the child. */
1.237 djm 648: switch ((pid = fork())) {
649: case -1:
650: error("%s: fork: %.100s", __func__, strerror(errno));
651: close(fdout);
652: close(ptymaster);
653: close(ttyfd);
654: close(ptyfd);
655: return -1;
656: case 0:
1.165 markus 657: is_child = 1;
1.97 markus 658:
1.237 djm 659: close(fdout);
660: close(ptymaster);
661:
1.24 markus 662: /* Child. Reinitialize the log because the pid has changed. */
1.237 djm 663: log_init(__progname, options.log_level,
664: options.log_facility, log_stderr);
1.1 markus 665: /* Close the master side of the pseudo tty. */
666: close(ptyfd);
667:
668: /* Make the pseudo tty our controlling tty. */
669: pty_make_controlling_tty(&ttyfd, s->tty);
670:
1.103 markus 671: /* Redirect stdin/stdout/stderr from the pseudo tty. */
672: if (dup2(ttyfd, 0) < 0)
673: error("dup2 stdin: %s", strerror(errno));
674: if (dup2(ttyfd, 1) < 0)
675: error("dup2 stdout: %s", strerror(errno));
676: if (dup2(ttyfd, 2) < 0)
677: error("dup2 stderr: %s", strerror(errno));
1.1 markus 678:
679: /* Close the extra descriptor for the pseudo tty. */
680: close(ttyfd);
681:
1.24 markus 682: /* record login, etc. similar to login(1) */
1.41 markus 683: if (!(options.use_login && command == NULL))
684: do_login(s, command);
1.228 djm 685:
1.237 djm 686: /*
687: * Do common processing for the child, such as execing
688: * the command.
689: */
1.60 markus 690: do_child(s, command);
1.1 markus 691: /* NOTREACHED */
1.237 djm 692: default:
693: break;
1.1 markus 694: }
695: s->pid = pid;
696:
697: /* Parent. Close the slave side of the pseudo tty. */
698: close(ttyfd);
699:
1.237 djm 700: /* Enter interactive session. */
1.1 markus 701: s->ptymaster = ptymaster;
1.257 djm 702: packet_set_interactive(1,
703: options.ip_qos_interactive, options.ip_qos_bulk);
1.2 markus 704: if (compat20) {
1.256 djm 705: session_set_fds(s, ptyfd, fdout, -1, 1, 1);
1.2 markus 706: } else {
707: server_loop(pid, ptyfd, fdout, -1);
708: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 709: }
1.237 djm 710: return 0;
1.24 markus 711: }
712:
1.90 markus 713: /*
714: * This is called to fork and execute a command. If another command is
715: * to be forced, execute that instead.
716: */
1.237 djm 717: int
1.90 markus 718: do_exec(Session *s, const char *command)
719: {
1.237 djm 720: int ret;
1.280 djm 721: const char *forced = NULL, *tty = NULL;
722: char session_type[1024];
1.237 djm 723:
1.210 dtucker 724: if (options.adm_forced_command) {
725: original_command = command;
726: command = options.adm_forced_command;
1.267 djm 727: forced = "(config)";
1.210 dtucker 728: } else if (forced_command) {
1.90 markus 729: original_command = command;
730: command = forced_command;
1.267 djm 731: forced = "(key-option)";
732: }
733: if (forced != NULL) {
1.248 djm 734: if (IS_INTERNAL_SFTP(command)) {
735: s->is_subsystem = s->is_subsystem ?
736: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
737: } else if (s->is_subsystem)
1.225 markus 738: s->is_subsystem = SUBSYSTEM_EXT;
1.267 djm 739: snprintf(session_type, sizeof(session_type),
740: "forced-command %s '%.900s'", forced, command);
741: } else if (s->is_subsystem) {
742: snprintf(session_type, sizeof(session_type),
743: "subsystem '%.900s'", s->subsys);
744: } else if (command == NULL) {
745: snprintf(session_type, sizeof(session_type), "shell");
746: } else {
747: /* NB. we don't log unforced commands to preserve privacy */
748: snprintf(session_type, sizeof(session_type), "command");
1.90 markus 749: }
1.163 markus 750:
1.267 djm 751: if (s->ttyfd != -1) {
752: tty = s->tty;
753: if (strncmp(tty, "/dev/", 5) == 0)
754: tty += 5;
755: }
756:
1.280 djm 757: verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
1.267 djm 758: session_type,
759: tty == NULL ? "" : " on ",
760: tty == NULL ? "" : tty,
761: s->pw->pw_name,
762: get_remote_ipaddr(),
1.280 djm 763: get_remote_port(),
764: s->self);
1.267 djm 765:
1.163 markus 766: #ifdef GSSAPI
767: if (options.gss_authentication) {
768: temporarily_use_uid(s->pw);
769: ssh_gssapi_storecreds();
770: restore_uid();
771: }
772: #endif
1.90 markus 773: if (s->ttyfd != -1)
1.237 djm 774: ret = do_exec_pty(s, command);
1.90 markus 775: else
1.237 djm 776: ret = do_exec_no_pty(s, command);
1.90 markus 777:
1.92 markus 778: original_command = NULL;
1.179 dtucker 779:
780: /*
781: * Clear loginmsg: it's the child's responsibility to display
782: * it to the user, otherwise multiple sessions may accumulate
783: * multiple copies of the login messages.
784: */
785: buffer_clear(&loginmsg);
1.237 djm 786:
787: return ret;
1.90 markus 788: }
789:
790:
1.24 markus 791: /* administrative, login(1)-like work */
792: void
1.41 markus 793: do_login(Session *s, const char *command)
1.24 markus 794: {
795: socklen_t fromlen;
796: struct sockaddr_storage from;
797: struct passwd * pw = s->pw;
798: pid_t pid = getpid();
799:
800: /*
801: * Get IP address of client. If the connection is not a socket, let
802: * the address be 0.0.0.0.
803: */
804: memset(&from, 0, sizeof(from));
1.148 stevesk 805: fromlen = sizeof(from);
1.24 markus 806: if (packet_connection_is_on_socket()) {
807: if (getpeername(packet_get_connection_in(),
1.200 deraadt 808: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 809: debug("getpeername: %.100s", strerror(errno));
1.165 markus 810: cleanup_exit(255);
1.24 markus 811: }
812: }
1.25 markus 813:
1.24 markus 814: /* Record that there was a login on that tty from the remote host. */
1.133 markus 815: if (!use_privsep)
816: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
817: get_remote_name_or_ip(utmp_len,
1.158 markus 818: options.use_dns),
1.148 stevesk 819: (struct sockaddr *)&from, fromlen);
1.24 markus 820:
1.73 djm 821: if (check_quietlogin(s, command))
1.24 markus 822: return;
1.73 djm 823:
1.179 dtucker 824: display_loginmsg();
1.73 djm 825:
826: do_motd();
827: }
828:
829: /*
830: * Display the message of the day.
831: */
832: void
833: do_motd(void)
834: {
835: FILE *f;
836: char buf[256];
837:
1.24 markus 838: if (options.print_motd) {
1.28 millert 839: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
840: "/etc/motd"), "r");
1.24 markus 841: if (f) {
842: while (fgets(buf, sizeof(buf), f))
843: fputs(buf, stdout);
844: fclose(f);
845: }
1.2 markus 846: }
1.73 djm 847: }
848:
849:
850: /*
851: * Check for quiet login, either .hushlogin or command given.
852: */
853: int
854: check_quietlogin(Session *s, const char *command)
855: {
856: char buf[256];
1.96 dugsong 857: struct passwd *pw = s->pw;
1.73 djm 858: struct stat st;
859:
860: /* Return 1 if .hushlogin exists or a command given. */
861: if (command != NULL)
862: return 1;
863: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
864: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
865: return 1;
866: return 0;
1.1 markus 867: }
868:
869: /*
870: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 871: * already exists, its value is overridden.
1.1 markus 872: */
1.161 markus 873: void
1.45 markus 874: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 875: const char *value)
1.1 markus 876: {
1.164 markus 877: char **env;
878: u_int envsize;
1.45 markus 879: u_int i, namelen;
1.1 markus 880:
1.271 djm 881: if (strchr(name, '=') != NULL) {
882: error("Invalid environment variable \"%.100s\"", name);
883: return;
884: }
885:
1.1 markus 886: /*
887: * Find the slot where the value should be stored. If the variable
888: * already exists, we reuse the slot; otherwise we append a new slot
889: * at the end of the array, expanding if necessary.
890: */
891: env = *envp;
892: namelen = strlen(name);
893: for (i = 0; env[i]; i++)
894: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
895: break;
896: if (env[i]) {
897: /* Reuse the slot. */
1.265 djm 898: free(env[i]);
1.1 markus 899: } else {
900: /* New variable. Expand if necessary. */
1.164 markus 901: envsize = *envsizep;
902: if (i >= envsize - 1) {
903: if (envsize >= 1000)
904: fatal("child_set_env: too many env vars");
905: envsize += 50;
1.278 deraadt 906: env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1.164 markus 907: *envsizep = envsize;
1.1 markus 908: }
909: /* Need to set the NULL pointer at end of array beyond the new slot. */
910: env[i + 1] = NULL;
911: }
912:
913: /* Allocate space and format the variable in the appropriate slot. */
914: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
915: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
916: }
917:
918: /*
919: * Reads environment variables from the given file and adds/overrides them
920: * into the environment. If the file does not exist, this does nothing.
921: * Otherwise, it must consist of empty lines, comments (line starts with '#')
922: * and assignments of the form name=value. No other forms are allowed.
923: */
1.94 itojun 924: static void
1.45 markus 925: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 926: const char *filename)
1.1 markus 927: {
928: FILE *f;
929: char buf[4096];
930: char *cp, *value;
1.142 deraadt 931: u_int lineno = 0;
1.1 markus 932:
933: f = fopen(filename, "r");
934: if (!f)
935: return;
936:
937: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 938: if (++lineno > 1000)
939: fatal("Too many lines in environment file %s", filename);
1.1 markus 940: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
941: ;
942: if (!*cp || *cp == '#' || *cp == '\n')
943: continue;
1.224 gilles 944:
945: cp[strcspn(cp, "\n")] = '\0';
946:
1.1 markus 947: value = strchr(cp, '=');
948: if (value == NULL) {
1.142 deraadt 949: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
950: filename);
1.1 markus 951: continue;
952: }
1.14 deraadt 953: /*
954: * Replace the equals sign by nul, and advance value to
955: * the value string.
956: */
1.1 markus 957: *value = '\0';
958: value++;
959: child_set_env(env, envsize, cp, value);
960: }
961: fclose(f);
962: }
963:
1.127 markus 964: static char **
965: do_setup_env(Session *s, const char *shell)
1.1 markus 966: {
967: char buf[256];
1.127 markus 968: u_int i, envsize;
1.154 markus 969: char **env, *laddr;
1.127 markus 970: struct passwd *pw = s->pw;
1.1 markus 971:
972: /* Initialize the environment. */
973: envsize = 100;
1.220 djm 974: env = xcalloc(envsize, sizeof(char *));
1.1 markus 975: env[0] = NULL;
976:
1.161 markus 977: #ifdef GSSAPI
1.168 djm 978: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 979: * the childs environment as they see fit
980: */
981: ssh_gssapi_do_child(&env, &envsize);
982: #endif
983:
1.1 markus 984: if (!options.use_login) {
985: /* Set basic environment. */
1.173 djm 986: for (i = 0; i < s->num_env; i++)
1.178 deraadt 987: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 988: s->env[i].val);
989:
1.1 markus 990: child_set_env(&env, &envsize, "USER", pw->pw_name);
991: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
992: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 993: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
994: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
995: else
996: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 997:
998: snprintf(buf, sizeof buf, "%.200s/%.50s",
999: _PATH_MAILDIR, pw->pw_name);
1000: child_set_env(&env, &envsize, "MAIL", buf);
1001:
1002: /* Normal systems set SHELL by default. */
1003: child_set_env(&env, &envsize, "SHELL", shell);
1004: }
1005: if (getenv("TZ"))
1006: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1007:
1008: /* Set custom environment options from RSA authentication. */
1.110 markus 1009: if (!options.use_login) {
1010: while (custom_environment) {
1011: struct envstring *ce = custom_environment;
1.143 deraadt 1012: char *str = ce->s;
1.127 markus 1013:
1.143 deraadt 1014: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 1015: ;
1.143 deraadt 1016: if (str[i] == '=') {
1017: str[i] = 0;
1018: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 1019: }
1020: custom_environment = ce->next;
1.265 djm 1021: free(ce->s);
1022: free(ce);
1.1 markus 1023: }
1024: }
1025:
1.149 stevesk 1026: /* SSH_CLIENT deprecated */
1.1 markus 1027: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 1028: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 1029: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1030:
1.154 markus 1031: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1032: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 1033: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1.265 djm 1034: free(laddr);
1.149 stevesk 1035: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1036:
1.60 markus 1037: if (s->ttyfd != -1)
1038: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1039: if (s->term)
1040: child_set_env(&env, &envsize, "TERM", s->term);
1041: if (s->display)
1042: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1043: if (original_command)
1044: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1045: original_command);
1.96 dugsong 1046: #ifdef KRB5
1047: if (s->authctxt->krb5_ticket_file)
1048: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1049: s->authctxt->krb5_ticket_file);
1.96 dugsong 1050: #endif
1.136 markus 1051: if (auth_sock_name != NULL)
1.1 markus 1052: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1053: auth_sock_name);
1.1 markus 1054:
1055: /* read $HOME/.ssh/environment. */
1.146 markus 1056: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1057: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1058: pw->pw_dir);
1.1 markus 1059: read_environment_file(&env, &envsize, buf);
1060: }
1061: if (debug_flag) {
1062: /* dump the environment */
1063: fprintf(stderr, "Environment:\n");
1064: for (i = 0; env[i]; i++)
1065: fprintf(stderr, " %.200s\n", env[i]);
1066: }
1.127 markus 1067: return env;
1068: }
1069:
1070: /*
1071: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1072: * first in this order).
1073: */
1074: static void
1075: do_rc_files(Session *s, const char *shell)
1076: {
1077: FILE *f = NULL;
1078: char cmd[1024];
1079: int do_xauth;
1080: struct stat st;
1081:
1082: do_xauth =
1083: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1084:
1.231 djm 1085: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1086: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.273 djm 1087: !no_user_rc && options.permit_user_rc &&
1088: stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1089: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1090: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1091: if (debug_flag)
1092: fprintf(stderr, "Running %s\n", cmd);
1093: f = popen(cmd, "w");
1094: if (f) {
1095: if (do_xauth)
1096: fprintf(f, "%s %s\n", s->auth_proto,
1097: s->auth_data);
1098: pclose(f);
1099: } else
1100: fprintf(stderr, "Could not run %s\n",
1101: _PATH_SSH_USER_RC);
1102: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1103: if (debug_flag)
1104: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1105: _PATH_SSH_SYSTEM_RC);
1106: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1107: if (f) {
1108: if (do_xauth)
1109: fprintf(f, "%s %s\n", s->auth_proto,
1110: s->auth_data);
1111: pclose(f);
1112: } else
1113: fprintf(stderr, "Could not run %s\n",
1114: _PATH_SSH_SYSTEM_RC);
1115: } else if (do_xauth && options.xauth_location != NULL) {
1116: /* Add authority data to .Xauthority if appropriate. */
1117: if (debug_flag) {
1118: fprintf(stderr,
1.151 stevesk 1119: "Running %.500s remove %.100s\n",
1.165 markus 1120: options.xauth_location, s->auth_display);
1.151 stevesk 1121: fprintf(stderr,
1122: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1123: options.xauth_location, s->auth_display,
1124: s->auth_proto, s->auth_data);
1125: }
1126: snprintf(cmd, sizeof cmd, "%s -q -",
1127: options.xauth_location);
1128: f = popen(cmd, "w");
1129: if (f) {
1.151 stevesk 1130: fprintf(f, "remove %s\n",
1131: s->auth_display);
1.127 markus 1132: fprintf(f, "add %s %s %s\n",
1133: s->auth_display, s->auth_proto,
1134: s->auth_data);
1135: pclose(f);
1136: } else {
1137: fprintf(stderr, "Could not run %s\n",
1138: cmd);
1139: }
1140: }
1141: }
1142:
1143: static void
1144: do_nologin(struct passwd *pw)
1145: {
1146: FILE *f = NULL;
1.251 dtucker 1147: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1148: struct stat sb;
1.127 markus 1149:
1.260 guenther 1150: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1151: return;
1152: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1153:
1154: if (stat(nl, &sb) == -1) {
1155: if (nl != def_nl)
1.265 djm 1156: free(nl);
1.251 dtucker 1157: return;
1158: }
1159:
1160: /* /etc/nologin exists. Print its contents if we can and exit. */
1161: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1162: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1163: while (fgets(buf, sizeof(buf), f))
1164: fputs(buf, stderr);
1165: fclose(f);
1166: }
1.251 dtucker 1167: exit(254);
1.127 markus 1168: }
1169:
1.226 djm 1170: /*
1171: * Chroot into a directory after checking it for safety: all path components
1172: * must be root-owned directories with strict permissions.
1173: */
1174: static void
1175: safely_chroot(const char *path, uid_t uid)
1176: {
1177: const char *cp;
1.277 deraadt 1178: char component[PATH_MAX];
1.226 djm 1179: struct stat st;
1180:
1181: if (*path != '/')
1182: fatal("chroot path does not begin at root");
1183: if (strlen(path) >= sizeof(component))
1184: fatal("chroot path too long");
1185:
1186: /*
1187: * Descend the path, checking that each component is a
1188: * root-owned directory with strict permissions.
1189: */
1190: for (cp = path; cp != NULL;) {
1191: if ((cp = strchr(cp, '/')) == NULL)
1192: strlcpy(component, path, sizeof(component));
1193: else {
1194: cp++;
1195: memcpy(component, path, cp - path);
1196: component[cp - path] = '\0';
1197: }
1198:
1199: debug3("%s: checking '%s'", __func__, component);
1200:
1201: if (stat(component, &st) != 0)
1202: fatal("%s: stat(\"%s\"): %s", __func__,
1203: component, strerror(errno));
1204: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1205: fatal("bad ownership or modes for chroot "
1206: "directory %s\"%s\"",
1207: cp == NULL ? "" : "component ", component);
1208: if (!S_ISDIR(st.st_mode))
1209: fatal("chroot path %s\"%s\" is not a directory",
1210: cp == NULL ? "" : "component ", component);
1211:
1212: }
1213:
1214: if (chdir(path) == -1)
1215: fatal("Unable to chdir to chroot path \"%s\": "
1216: "%s", path, strerror(errno));
1217: if (chroot(path) == -1)
1218: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1219: if (chdir("/") == -1)
1220: fatal("%s: chdir(/) after chroot: %s",
1221: __func__, strerror(errno));
1222: verbose("Changed root directory to \"%s\"", path);
1223: }
1224:
1.127 markus 1225: /* Set login name, uid, gid, and groups. */
1.130 provos 1226: void
1.127 markus 1227: do_setusercontext(struct passwd *pw)
1228: {
1.227 djm 1229: char *chroot_path, *tmp;
1230:
1.127 markus 1231: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1232: /* Prepare groups */
1.127 markus 1233: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1234: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1235: perror("unable to set user context");
1236: exit(1);
1237: }
1.226 djm 1238:
1.279 djm 1239: if (!in_chroot && options.chroot_directory != NULL &&
1.226 djm 1240: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1241: tmp = tilde_expand_filename(options.chroot_directory,
1242: pw->pw_uid);
1243: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1244: "u", pw->pw_name, (char *)NULL);
1.226 djm 1245: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1246: free(tmp);
1.226 djm 1247: free(chroot_path);
1.264 djm 1248: /* Make sure we don't attempt to chroot again */
1249: free(options.chroot_directory);
1250: options.chroot_directory = NULL;
1.279 djm 1251: in_chroot = 1;
1.226 djm 1252: }
1253:
1254: /* Set UID */
1255: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1256: perror("unable to set user context (setuser)");
1257: exit(1);
1258: }
1.264 djm 1259: } else if (options.chroot_directory != NULL &&
1260: strcasecmp(options.chroot_directory, "none") != 0) {
1261: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1262: }
1.264 djm 1263:
1.127 markus 1264: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1265: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1266: }
1267:
1.131 markus 1268: static void
1.172 markus 1269: do_pwchange(Session *s)
1270: {
1.179 dtucker 1271: fflush(NULL);
1.172 markus 1272: fprintf(stderr, "WARNING: Your password has expired.\n");
1273: if (s->ttyfd != -1) {
1.178 deraadt 1274: fprintf(stderr,
1.172 markus 1275: "You must change your password now and login again!\n");
1276: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1277: perror("passwd");
1278: } else {
1279: fprintf(stderr,
1280: "Password change required but no TTY available.\n");
1281: }
1282: exit(1);
1283: }
1284:
1285: static void
1.130 provos 1286: launch_login(struct passwd *pw, const char *hostname)
1287: {
1288: /* Launch login(1). */
1289:
1290: execl("/usr/bin/login", "login", "-h", hostname,
1291: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1292:
1293: /* Login couldn't be executed, die. */
1294:
1295: perror("login");
1296: exit(1);
1297: }
1298:
1.172 markus 1299: static void
1300: child_close_fds(void)
1301: {
1.276 djm 1302: extern int auth_sock;
1.266 markus 1303:
1.276 djm 1304: if (auth_sock != -1) {
1305: close(auth_sock);
1306: auth_sock = -1;
1.266 markus 1307: }
1308:
1.172 markus 1309: if (packet_get_connection_in() == packet_get_connection_out())
1310: close(packet_get_connection_in());
1311: else {
1312: close(packet_get_connection_in());
1313: close(packet_get_connection_out());
1314: }
1315: /*
1316: * Close all descriptors related to channels. They will still remain
1317: * open in the parent.
1318: */
1319: /* XXX better use close-on-exec? -markus */
1320: channel_close_all();
1321:
1322: /*
1323: * Close any extra file descriptors. Note that there may still be
1324: * descriptors left by system functions. They will be closed later.
1325: */
1326: endpwent();
1327:
1328: /*
1.188 djm 1329: * Close any extra open file descriptors so that we don't have them
1.172 markus 1330: * hanging around in clients. Note that we want to do this after
1331: * initgroups, because at least on Solaris 2.3 it leaves file
1332: * descriptors open.
1333: */
1.258 djm 1334: closefrom(STDERR_FILENO + 1);
1.172 markus 1335: }
1336:
1.127 markus 1337: /*
1338: * Performs common processing for the child, such as setting up the
1339: * environment, closing extra file descriptors, setting the user and group
1340: * ids, and executing the command or shell.
1341: */
1.225 markus 1342: #define ARGV_MAX 10
1.127 markus 1343: void
1344: do_child(Session *s, const char *command)
1345: {
1346: extern char **environ;
1347: char **env;
1.225 markus 1348: char *argv[ARGV_MAX];
1.127 markus 1349: const char *shell, *shell0, *hostname = NULL;
1350: struct passwd *pw = s->pw;
1.239 djm 1351: int r = 0;
1.127 markus 1352:
1353: /* remove hostkey from the child's memory */
1354: destroy_sensitive_data();
1355:
1.172 markus 1356: /* Force a password change */
1357: if (s->authctxt->force_pwchange) {
1358: do_setusercontext(pw);
1359: child_close_fds();
1360: do_pwchange(s);
1361: exit(1);
1362: }
1363:
1.127 markus 1364: /* login(1) is only called if we execute the login shell */
1365: if (options.use_login && command != NULL)
1366: options.use_login = 0;
1367:
1368: /*
1369: * Login(1) does this as well, and it needs uid 0 for the "-h"
1370: * switch, so we let login(1) to this for us.
1371: */
1372: if (!options.use_login) {
1373: do_nologin(pw);
1374: do_setusercontext(pw);
1375: }
1376:
1377: /*
1378: * Get the shell from the password data. An empty shell field is
1379: * legal, and means /bin/sh.
1380: */
1381: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1382:
1383: /*
1384: * Make sure $SHELL points to the shell from the password file,
1385: * even if shell is overridden from login.conf
1386: */
1387: env = do_setup_env(s, shell);
1388:
1.127 markus 1389: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1390:
1.26 millert 1391: /* we have to stash the hostname before we close our socket. */
1392: if (options.use_login)
1.70 stevesk 1393: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1394: options.use_dns);
1.1 markus 1395: /*
1396: * Close the connection descriptors; note that this is the child, and
1397: * the server will still have the socket open, and it is important
1398: * that we do not shutdown it. Note that the descriptors cannot be
1399: * closed before building the environment, as we call
1400: * get_remote_ipaddr there.
1401: */
1.172 markus 1402: child_close_fds();
1.1 markus 1403:
1404: /*
1.125 deraadt 1405: * Must take new environment into use so that .ssh/rc,
1406: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1407: */
1408: environ = env;
1.170 jakob 1409:
1410: #ifdef KRB5
1411: /*
1412: * At this point, we check to see if AFS is active and if we have
1413: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1414: * if we can (and need to) extend the ticket into an AFS token. If
1415: * we don't do this, we run into potential problems if the user's
1416: * home directory is in AFS and it's not world-readable.
1417: */
1418:
1419: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1420: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1421: char cell[64];
1422:
1423: debug("Getting AFS token");
1424:
1425: k_setpag();
1426:
1427: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1428: krb5_afslog(s->authctxt->krb5_ctx,
1429: s->authctxt->krb5_fwd_ccache, cell, NULL);
1430:
1431: krb5_afslog_home(s->authctxt->krb5_ctx,
1432: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1433: }
1434: #endif
1.104 markus 1435:
1.188 djm 1436: /* Change current directory to the user's home directory. */
1.104 markus 1437: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1438: /* Suppress missing homedir warning for chroot case */
1439: r = login_getcapbool(lc, "requirehome", 0);
1.279 djm 1440: if (r || !in_chroot) {
1.239 djm 1441: fprintf(stderr, "Could not chdir to home "
1442: "directory %s: %s\n", pw->pw_dir,
1443: strerror(errno));
1.279 djm 1444: }
1.239 djm 1445: if (r)
1.104 markus 1446: exit(1);
1447: }
1.230 djm 1448:
1449: closefrom(STDERR_FILENO + 1);
1.1 markus 1450:
1.127 markus 1451: if (!options.use_login)
1452: do_rc_files(s, shell);
1.67 markus 1453:
1454: /* restore SIGPIPE for child */
1.217 stevesk 1455: signal(SIGPIPE, SIG_DFL);
1.67 markus 1456:
1.248 djm 1457: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1458: printf("This service allows sftp connections only.\n");
1459: fflush(NULL);
1460: exit(1);
1461: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1462: extern int optind, optreset;
1463: int i;
1464: char *p, *args;
1465:
1.246 stevesk 1466: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1467: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1468: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1469: if (i < ARGV_MAX - 1)
1470: argv[i++] = p;
1471: argv[i] = NULL;
1472: optind = optreset = 1;
1473: __progname = argv[0];
1.226 djm 1474: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1475: }
1.247 djm 1476:
1477: fflush(NULL);
1.225 markus 1478:
1.127 markus 1479: if (options.use_login) {
1.130 provos 1480: launch_login(pw, hostname);
1481: /* NEVERREACHED */
1.127 markus 1482: }
1483:
1484: /* Get the last component of the shell name. */
1485: if ((shell0 = strrchr(shell, '/')) != NULL)
1486: shell0++;
1487: else
1488: shell0 = shell;
1489:
1.1 markus 1490: /*
1491: * If we have no command, execute the shell. In this case, the shell
1492: * name to be passed in argv[0] is preceded by '-' to indicate that
1493: * this is a login shell.
1494: */
1495: if (!command) {
1.127 markus 1496: char argv0[256];
1.1 markus 1497:
1.127 markus 1498: /* Start the shell. Set initial character to '-'. */
1499: argv0[0] = '-';
1.1 markus 1500:
1.127 markus 1501: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1502: >= sizeof(argv0) - 1) {
1.127 markus 1503: errno = EINVAL;
1.1 markus 1504: perror(shell);
1505: exit(1);
1.127 markus 1506: }
1.1 markus 1507:
1.127 markus 1508: /* Execute the shell. */
1509: argv[0] = argv0;
1510: argv[1] = NULL;
1511: execve(shell, argv, env);
1512:
1513: /* Executing the shell failed. */
1514: perror(shell);
1515: exit(1);
1.1 markus 1516: }
1517: /*
1518: * Execute the command using the user's shell. This uses the -c
1519: * option to execute the command.
1520: */
1.127 markus 1521: argv[0] = (char *) shell0;
1.1 markus 1522: argv[1] = "-c";
1523: argv[2] = (char *) command;
1524: argv[3] = NULL;
1525: execve(shell, argv, env);
1526: perror(shell);
1527: exit(1);
1528: }
1529:
1.237 djm 1530: void
1531: session_unused(int id)
1532: {
1533: debug3("%s: session id %d unused", __func__, id);
1534: if (id >= options.max_sessions ||
1535: id >= sessions_nalloc) {
1536: fatal("%s: insane session id %d (max %d nalloc %d)",
1537: __func__, id, options.max_sessions, sessions_nalloc);
1538: }
1.270 tedu 1539: memset(&sessions[id], 0, sizeof(*sessions));
1.237 djm 1540: sessions[id].self = id;
1541: sessions[id].used = 0;
1542: sessions[id].chanid = -1;
1543: sessions[id].ptyfd = -1;
1544: sessions[id].ttyfd = -1;
1545: sessions[id].ptymaster = -1;
1546: sessions[id].x11_chanids = NULL;
1547: sessions[id].next_unused = sessions_first_unused;
1548: sessions_first_unused = id;
1549: }
1550:
1.1 markus 1551: Session *
1552: session_new(void)
1553: {
1.237 djm 1554: Session *s, *tmp;
1555:
1556: if (sessions_first_unused == -1) {
1557: if (sessions_nalloc >= options.max_sessions)
1558: return NULL;
1559: debug2("%s: allocate (allocated %d max %d)",
1560: __func__, sessions_nalloc, options.max_sessions);
1.278 deraadt 1561: tmp = xreallocarray(sessions, sessions_nalloc + 1,
1.237 djm 1562: sizeof(*sessions));
1563: if (tmp == NULL) {
1564: error("%s: cannot allocate %d sessions",
1565: __func__, sessions_nalloc + 1);
1566: return NULL;
1567: }
1568: sessions = tmp;
1569: session_unused(sessions_nalloc++);
1570: }
1571:
1572: if (sessions_first_unused >= sessions_nalloc ||
1573: sessions_first_unused < 0) {
1574: fatal("%s: insane first_unused %d max %d nalloc %d",
1575: __func__, sessions_first_unused, options.max_sessions,
1576: sessions_nalloc);
1577: }
1578:
1579: s = &sessions[sessions_first_unused];
1580: if (s->used) {
1581: fatal("%s: session %d already used",
1582: __func__, sessions_first_unused);
1583: }
1584: sessions_first_unused = s->next_unused;
1585: s->used = 1;
1586: s->next_unused = -1;
1587: debug("session_new: session %d", s->self);
1588:
1589: return s;
1.1 markus 1590: }
1591:
1.94 itojun 1592: static void
1.1 markus 1593: session_dump(void)
1594: {
1595: int i;
1.237 djm 1596: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1597: Session *s = &sessions[i];
1.237 djm 1598:
1599: debug("dump: used %d next_unused %d session %d %p "
1600: "channel %d pid %ld",
1.1 markus 1601: s->used,
1.237 djm 1602: s->next_unused,
1.1 markus 1603: s->self,
1604: s,
1605: s->chanid,
1.137 mpech 1606: (long)s->pid);
1.1 markus 1607: }
1608: }
1609:
1.2 markus 1610: int
1.97 markus 1611: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1612: {
1613: Session *s = session_new();
1614: debug("session_open: channel %d", chanid);
1615: if (s == NULL) {
1616: error("no more sessions");
1617: return 0;
1618: }
1.97 markus 1619: s->authctxt = authctxt;
1620: s->pw = authctxt->pw;
1.167 djm 1621: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1622: fatal("no user for session %d", s->self);
1.2 markus 1623: debug("session_open: session %d: link with channel %d", s->self, chanid);
1624: s->chanid = chanid;
1625: return 1;
1626: }
1627:
1.130 provos 1628: Session *
1629: session_by_tty(char *tty)
1630: {
1631: int i;
1.237 djm 1632: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1633: Session *s = &sessions[i];
1634: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1635: debug("session_by_tty: session %d tty %s", i, tty);
1636: return s;
1637: }
1638: }
1639: debug("session_by_tty: unknown tty %.100s", tty);
1640: session_dump();
1641: return NULL;
1642: }
1643:
1.94 itojun 1644: static Session *
1.2 markus 1645: session_by_channel(int id)
1646: {
1647: int i;
1.237 djm 1648: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1649: Session *s = &sessions[i];
1650: if (s->used && s->chanid == id) {
1.237 djm 1651: debug("session_by_channel: session %d channel %d",
1652: i, id);
1.2 markus 1653: return s;
1654: }
1655: }
1656: debug("session_by_channel: unknown channel %d", id);
1657: session_dump();
1658: return NULL;
1659: }
1660:
1.94 itojun 1661: static Session *
1.184 djm 1662: session_by_x11_channel(int id)
1663: {
1664: int i, j;
1665:
1.237 djm 1666: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1667: Session *s = &sessions[i];
1668:
1669: if (s->x11_chanids == NULL || !s->used)
1670: continue;
1671: for (j = 0; s->x11_chanids[j] != -1; j++) {
1672: if (s->x11_chanids[j] == id) {
1673: debug("session_by_x11_channel: session %d "
1674: "channel %d", s->self, id);
1675: return s;
1676: }
1677: }
1678: }
1679: debug("session_by_x11_channel: unknown channel %d", id);
1680: session_dump();
1681: return NULL;
1682: }
1683:
1684: static Session *
1.2 markus 1685: session_by_pid(pid_t pid)
1686: {
1687: int i;
1.137 mpech 1688: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1689: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1690: Session *s = &sessions[i];
1691: if (s->used && s->pid == pid)
1692: return s;
1693: }
1.137 mpech 1694: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1695: session_dump();
1696: return NULL;
1697: }
1698:
1.94 itojun 1699: static int
1.2 markus 1700: session_window_change_req(Session *s)
1701: {
1702: s->col = packet_get_int();
1703: s->row = packet_get_int();
1704: s->xpixel = packet_get_int();
1705: s->ypixel = packet_get_int();
1.116 markus 1706: packet_check_eom();
1.2 markus 1707: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1708: return 1;
1709: }
1710:
1.94 itojun 1711: static int
1.2 markus 1712: session_pty_req(Session *s)
1713: {
1.45 markus 1714: u_int len;
1.72 stevesk 1715: int n_bytes;
1.132 markus 1716:
1.268 djm 1717: if (no_pty_flag || !options.permit_tty) {
1.86 markus 1718: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1719: return 0;
1.86 markus 1720: }
1721: if (s->ttyfd != -1) {
1722: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1723: return 0;
1.86 markus 1724: }
1725:
1.2 markus 1726: s->term = packet_get_string(&len);
1.86 markus 1727:
1728: if (compat20) {
1729: s->col = packet_get_int();
1730: s->row = packet_get_int();
1731: } else {
1732: s->row = packet_get_int();
1733: s->col = packet_get_int();
1734: }
1.2 markus 1735: s->xpixel = packet_get_int();
1736: s->ypixel = packet_get_int();
1737:
1738: if (strcmp(s->term, "") == 0) {
1.265 djm 1739: free(s->term);
1.2 markus 1740: s->term = NULL;
1741: }
1.86 markus 1742:
1.2 markus 1743: /* Allocate a pty and open it. */
1.86 markus 1744: debug("Allocating pty.");
1.237 djm 1745: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1746: sizeof(s->tty)))) {
1.265 djm 1747: free(s->term);
1.2 markus 1748: s->term = NULL;
1749: s->ptyfd = -1;
1750: s->ttyfd = -1;
1751: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1752: return 0;
1.2 markus 1753: }
1754: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1755:
1756: /* for SSH1 the tty modes length is not given */
1757: if (!compat20)
1758: n_bytes = packet_remaining();
1759: tty_parse_modes(s->ttyfd, &n_bytes);
1760:
1.130 provos 1761: if (!use_privsep)
1762: pty_setowner(s->pw, s->tty);
1.86 markus 1763:
1764: /* Set window size from the packet. */
1.2 markus 1765: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1766:
1.116 markus 1767: packet_check_eom();
1.9 markus 1768: session_proctitle(s);
1.2 markus 1769: return 1;
1770: }
1771:
1.94 itojun 1772: static int
1.7 markus 1773: session_subsystem_req(Session *s)
1774: {
1.105 markus 1775: struct stat st;
1.45 markus 1776: u_int len;
1.7 markus 1777: int success = 0;
1.267 djm 1778: char *prog, *cmd;
1.182 djm 1779: u_int i;
1.7 markus 1780:
1.267 djm 1781: s->subsys = packet_get_string(&len);
1.116 markus 1782: packet_check_eom();
1.267 djm 1783: debug2("subsystem request for %.100s by user %s", s->subsys,
1.255 djm 1784: s->pw->pw_name);
1.18 jakob 1785:
1786: for (i = 0; i < options.num_subsystems; i++) {
1.267 djm 1787: if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1788: prog = options.subsystem_command[i];
1789: cmd = options.subsystem_args[i];
1.249 dtucker 1790: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1791: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1792: debug("subsystem: %s", prog);
1.225 markus 1793: } else {
1.249 dtucker 1794: if (stat(prog, &st) < 0)
1795: debug("subsystem: cannot stat %s: %s",
1796: prog, strerror(errno));
1.225 markus 1797: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1798: debug("subsystem: exec() %s", cmd);
1.105 markus 1799: }
1.237 djm 1800: success = do_exec(s, cmd) == 0;
1.122 markus 1801: break;
1.18 jakob 1802: }
1803: }
1804:
1805: if (!success)
1.267 djm 1806: logit("subsystem request for %.100s by user %s failed, "
1807: "subsystem not found", s->subsys, s->pw->pw_name);
1.7 markus 1808:
1809: return success;
1810: }
1811:
1.94 itojun 1812: static int
1.7 markus 1813: session_x11_req(Session *s)
1814: {
1.81 markus 1815: int success;
1.7 markus 1816:
1.184 djm 1817: if (s->auth_proto != NULL || s->auth_data != NULL) {
1818: error("session_x11_req: session %d: "
1.190 stevesk 1819: "x11 forwarding already active", s->self);
1.184 djm 1820: return 0;
1821: }
1.7 markus 1822: s->single_connection = packet_get_char();
1823: s->auth_proto = packet_get_string(NULL);
1824: s->auth_data = packet_get_string(NULL);
1825: s->screen = packet_get_int();
1.116 markus 1826: packet_check_eom();
1.7 markus 1827:
1.280.2.1! djm 1828: if (xauth_valid_string(s->auth_proto) &&
! 1829: xauth_valid_string(s->auth_data))
! 1830: success = session_setup_x11fwd(s);
! 1831: else {
! 1832: success = 0;
! 1833: error("Invalid X11 forwarding data");
! 1834: }
1.81 markus 1835: if (!success) {
1.265 djm 1836: free(s->auth_proto);
1837: free(s->auth_data);
1.84 markus 1838: s->auth_proto = NULL;
1839: s->auth_data = NULL;
1.7 markus 1840: }
1.81 markus 1841: return success;
1.7 markus 1842: }
1843:
1.94 itojun 1844: static int
1.19 markus 1845: session_shell_req(Session *s)
1846: {
1.116 markus 1847: packet_check_eom();
1.237 djm 1848: return do_exec(s, NULL) == 0;
1.19 markus 1849: }
1850:
1.94 itojun 1851: static int
1.19 markus 1852: session_exec_req(Session *s)
1853: {
1.237 djm 1854: u_int len, success;
1855:
1.19 markus 1856: char *command = packet_get_string(&len);
1.116 markus 1857: packet_check_eom();
1.237 djm 1858: success = do_exec(s, command) == 0;
1.265 djm 1859: free(command);
1.237 djm 1860: return success;
1.19 markus 1861: }
1862:
1.94 itojun 1863: static int
1.157 markus 1864: session_break_req(Session *s)
1865: {
1866:
1.175 deraadt 1867: packet_get_int(); /* ignored */
1.157 markus 1868: packet_check_eom();
1869:
1.259 djm 1870: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1871: return 0;
1872: return 1;
1873: }
1874:
1875: static int
1.173 djm 1876: session_env_req(Session *s)
1877: {
1878: char *name, *val;
1879: u_int name_len, val_len, i;
1880:
1.271 djm 1881: name = packet_get_cstring(&name_len);
1882: val = packet_get_cstring(&val_len);
1.173 djm 1883: packet_check_eom();
1884:
1885: /* Don't set too many environment variables */
1886: if (s->num_env > 128) {
1887: debug2("Ignoring env request %s: too many env vars", name);
1888: goto fail;
1889: }
1890:
1891: for (i = 0; i < options.num_accept_env; i++) {
1892: if (match_pattern(name, options.accept_env[i])) {
1893: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.278 deraadt 1894: s->env = xreallocarray(s->env, s->num_env + 1,
1.201 djm 1895: sizeof(*s->env));
1.173 djm 1896: s->env[s->num_env].name = name;
1897: s->env[s->num_env].val = val;
1898: s->num_env++;
1899: return (1);
1900: }
1901: }
1902: debug2("Ignoring env request %s: disallowed name", name);
1903:
1904: fail:
1.265 djm 1905: free(name);
1906: free(val);
1.173 djm 1907: return (0);
1908: }
1909:
1910: static int
1.43 markus 1911: session_auth_agent_req(Session *s)
1912: {
1913: static int called = 0;
1.116 markus 1914: packet_check_eom();
1.235 pyr 1915: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1916: debug("session_auth_agent_req: no_agent_forwarding_flag");
1917: return 0;
1918: }
1.43 markus 1919: if (called) {
1920: return 0;
1921: } else {
1922: called = 1;
1923: return auth_input_request_forwarding(s->pw);
1924: }
1925: }
1926:
1.123 markus 1927: int
1928: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1929: {
1930: int success = 0;
1931: Session *s;
1932:
1.123 markus 1933: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1934: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1935: c->self, rtype);
1936: return 0;
1937: }
1938: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1939:
1940: /*
1.64 markus 1941: * a session is in LARVAL state until a shell, a command
1942: * or a subsystem is executed
1.2 markus 1943: */
1944: if (c->type == SSH_CHANNEL_LARVAL) {
1945: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1946: success = session_shell_req(s);
1.2 markus 1947: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1948: success = session_exec_req(s);
1.2 markus 1949: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1950: success = session_pty_req(s);
1.7 markus 1951: } else if (strcmp(rtype, "x11-req") == 0) {
1952: success = session_x11_req(s);
1.43 markus 1953: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1954: success = session_auth_agent_req(s);
1.7 markus 1955: } else if (strcmp(rtype, "subsystem") == 0) {
1956: success = session_subsystem_req(s);
1.173 djm 1957: } else if (strcmp(rtype, "env") == 0) {
1958: success = session_env_req(s);
1.2 markus 1959: }
1960: }
1961: if (strcmp(rtype, "window-change") == 0) {
1962: success = session_window_change_req(s);
1.177 djm 1963: } else if (strcmp(rtype, "break") == 0) {
1964: success = session_break_req(s);
1.2 markus 1965: }
1.177 djm 1966:
1.123 markus 1967: return success;
1.2 markus 1968: }
1969:
1970: void
1.256 djm 1971: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1972: int is_tty)
1.2 markus 1973: {
1974: if (!compat20)
1975: fatal("session_set_fds: called for proto != 2.0");
1976: /*
1977: * now that have a child and a pipe to the child,
1978: * we can activate our channel and register the fd's
1979: */
1980: if (s->chanid == -1)
1981: fatal("no channel for session %d", s->self);
1982: channel_set_fds(s->chanid,
1983: fdout, fdin, fderr,
1.256 djm 1984: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1985: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1986: }
1987:
1.85 markus 1988: /*
1989: * Function to perform pty cleanup. Also called if we get aborted abnormally
1990: * (e.g., due to a dropped connection).
1991: */
1.130 provos 1992: void
1.165 markus 1993: session_pty_cleanup2(Session *s)
1.1 markus 1994: {
1.85 markus 1995: if (s == NULL) {
1996: error("session_pty_cleanup: no session");
1997: return;
1998: }
1999: if (s->ttyfd == -1)
1.1 markus 2000: return;
2001:
1.54 stevesk 2002: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 2003:
2004: /* Record that the user has logged out. */
1.85 markus 2005: if (s->pid != 0)
2006: record_logout(s->pid, s->tty);
1.1 markus 2007:
2008: /* Release the pseudo-tty. */
1.130 provos 2009: if (getuid() == 0)
2010: pty_release(s->tty);
1.1 markus 2011:
2012: /*
2013: * Close the server side of the socket pairs. We must do this after
2014: * the pty cleanup, so that another process doesn't get this pty
2015: * while we're still cleaning up.
2016: */
1.237 djm 2017: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2018: error("close(s->ptymaster/%d): %s",
2019: s->ptymaster, strerror(errno));
1.108 markus 2020:
2021: /* unlink pty from session */
2022: s->ttyfd = -1;
1.2 markus 2023: }
2024:
1.130 provos 2025: void
1.165 markus 2026: session_pty_cleanup(Session *s)
1.130 provos 2027: {
1.165 markus 2028: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 2029: }
2030:
1.147 markus 2031: static char *
2032: sig2name(int sig)
2033: {
2034: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2035: SSH_SIG(ABRT);
2036: SSH_SIG(ALRM);
2037: SSH_SIG(FPE);
2038: SSH_SIG(HUP);
2039: SSH_SIG(ILL);
2040: SSH_SIG(INT);
2041: SSH_SIG(KILL);
2042: SSH_SIG(PIPE);
2043: SSH_SIG(QUIT);
2044: SSH_SIG(SEGV);
2045: SSH_SIG(TERM);
2046: SSH_SIG(USR1);
2047: SSH_SIG(USR2);
2048: #undef SSH_SIG
2049: return "SIG@openssh.com";
2050: }
2051:
1.94 itojun 2052: static void
1.184 djm 2053: session_close_x11(int id)
2054: {
2055: Channel *c;
2056:
1.189 markus 2057: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2058: debug("session_close_x11: x11 channel %d missing", id);
2059: } else {
2060: /* Detach X11 listener */
2061: debug("session_close_x11: detach x11 channel %d", id);
2062: channel_cancel_cleanup(id);
2063: if (c->ostate != CHAN_OUTPUT_CLOSED)
2064: chan_mark_dead(c);
2065: }
2066: }
2067:
2068: static void
2069: session_close_single_x11(int id, void *arg)
2070: {
2071: Session *s;
2072: u_int i;
2073:
2074: debug3("session_close_single_x11: channel %d", id);
2075: channel_cancel_cleanup(id);
1.221 stevesk 2076: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2077: fatal("session_close_single_x11: no x11 channel %d", id);
2078: for (i = 0; s->x11_chanids[i] != -1; i++) {
2079: debug("session_close_single_x11: session %d: "
2080: "closing channel %d", s->self, s->x11_chanids[i]);
2081: /*
2082: * The channel "id" is already closing, but make sure we
2083: * close all of its siblings.
2084: */
2085: if (s->x11_chanids[i] != id)
2086: session_close_x11(s->x11_chanids[i]);
2087: }
1.265 djm 2088: free(s->x11_chanids);
1.184 djm 2089: s->x11_chanids = NULL;
1.265 djm 2090: free(s->display);
2091: s->display = NULL;
2092: free(s->auth_proto);
2093: s->auth_proto = NULL;
2094: free(s->auth_data);
2095: s->auth_data = NULL;
2096: free(s->auth_display);
2097: s->auth_display = NULL;
1.184 djm 2098: }
2099:
2100: static void
1.2 markus 2101: session_exit_message(Session *s, int status)
2102: {
2103: Channel *c;
1.124 markus 2104:
2105: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2106: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2107: s->self, s->chanid);
1.137 mpech 2108: debug("session_exit_message: session %d channel %d pid %ld",
2109: s->self, s->chanid, (long)s->pid);
1.2 markus 2110:
2111: if (WIFEXITED(status)) {
1.124 markus 2112: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2113: packet_put_int(WEXITSTATUS(status));
2114: packet_send();
2115: } else if (WIFSIGNALED(status)) {
1.124 markus 2116: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2117: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2118: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2119: packet_put_cstring("");
2120: packet_put_cstring("");
2121: packet_send();
2122: } else {
2123: /* Some weird exit cause. Just exit. */
2124: packet_disconnect("wait returned status %04x.", status);
2125: }
2126:
2127: /* disconnect channel */
2128: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2129:
2130: /*
2131: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2132: * the channel gets EOF. The session will be then be closed
1.187 djm 2133: * by session_close_by_channel when the childs close their fds.
2134: */
2135: channel_register_cleanup(c->self, session_close_by_channel, 1);
2136:
1.5 markus 2137: /*
2138: * emulate a write failure with 'chan_write_failed', nobody will be
2139: * interested in data we write.
2140: * Note that we must not call 'chan_read_failed', since there could
2141: * be some more data waiting in the pipe.
2142: */
1.8 markus 2143: if (c->ostate != CHAN_OUTPUT_CLOSED)
2144: chan_write_failed(c);
1.2 markus 2145: }
2146:
1.130 provos 2147: void
1.85 markus 2148: session_close(Session *s)
1.2 markus 2149: {
1.182 djm 2150: u_int i;
1.173 djm 2151:
1.280 djm 2152: verbose("Close session: user %s from %.200s port %d id %d",
2153: s->pw->pw_name,
2154: get_remote_ipaddr(),
2155: get_remote_port(),
2156: s->self);
2157:
1.165 markus 2158: if (s->ttyfd != -1)
1.85 markus 2159: session_pty_cleanup(s);
1.265 djm 2160: free(s->term);
2161: free(s->display);
2162: free(s->x11_chanids);
2163: free(s->auth_display);
2164: free(s->auth_data);
2165: free(s->auth_proto);
1.267 djm 2166: free(s->subsys);
1.219 djm 2167: if (s->env != NULL) {
2168: for (i = 0; i < s->num_env; i++) {
1.265 djm 2169: free(s->env[i].name);
2170: free(s->env[i].val);
1.219 djm 2171: }
1.265 djm 2172: free(s->env);
1.173 djm 2173: }
1.9 markus 2174: session_proctitle(s);
1.237 djm 2175: session_unused(s->self);
1.2 markus 2176: }
2177:
2178: void
2179: session_close_by_pid(pid_t pid, int status)
2180: {
2181: Session *s = session_by_pid(pid);
2182: if (s == NULL) {
1.137 mpech 2183: debug("session_close_by_pid: no session for pid %ld",
2184: (long)pid);
1.2 markus 2185: return;
2186: }
2187: if (s->chanid != -1)
2188: session_exit_message(s, status);
1.187 djm 2189: if (s->ttyfd != -1)
2190: session_pty_cleanup(s);
1.197 djm 2191: s->pid = 0;
1.98 markus 2192: }
2193:
1.2 markus 2194: /*
2195: * this is called when a channel dies before
2196: * the session 'child' itself dies
2197: */
2198: void
2199: session_close_by_channel(int id, void *arg)
2200: {
2201: Session *s = session_by_channel(id);
1.187 djm 2202: u_int i;
1.184 djm 2203:
1.2 markus 2204: if (s == NULL) {
1.107 markus 2205: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2206: return;
2207: }
1.137 mpech 2208: debug("session_close_by_channel: channel %d child %ld",
2209: id, (long)s->pid);
1.107 markus 2210: if (s->pid != 0) {
2211: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2212: /*
2213: * delay detach of session, but release pty, since
2214: * the fd's to the child are already closed
2215: */
1.165 markus 2216: if (s->ttyfd != -1)
1.108 markus 2217: session_pty_cleanup(s);
1.107 markus 2218: return;
2219: }
2220: /* detach by removing callback */
1.2 markus 2221: channel_cancel_cleanup(s->chanid);
1.187 djm 2222:
2223: /* Close any X11 listeners associated with this session */
2224: if (s->x11_chanids != NULL) {
2225: for (i = 0; s->x11_chanids[i] != -1; i++) {
2226: session_close_x11(s->x11_chanids[i]);
2227: s->x11_chanids[i] = -1;
2228: }
2229: }
2230:
1.2 markus 2231: s->chanid = -1;
1.106 markus 2232: session_close(s);
2233: }
2234:
2235: void
1.130 provos 2236: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2237: {
2238: int i;
1.237 djm 2239: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2240: Session *s = &sessions[i];
1.130 provos 2241: if (s->used) {
2242: if (closefunc != NULL)
2243: closefunc(s);
2244: else
2245: session_close(s);
2246: }
1.2 markus 2247: }
1.9 markus 2248: }
2249:
1.94 itojun 2250: static char *
1.9 markus 2251: session_tty_list(void)
2252: {
2253: static char buf[1024];
2254: int i;
2255: buf[0] = '\0';
1.237 djm 2256: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2257: Session *s = &sessions[i];
2258: if (s->used && s->ttyfd != -1) {
2259: if (buf[0] != '\0')
2260: strlcat(buf, ",", sizeof buf);
2261: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2262: }
2263: }
2264: if (buf[0] == '\0')
2265: strlcpy(buf, "notty", sizeof buf);
2266: return buf;
2267: }
2268:
2269: void
2270: session_proctitle(Session *s)
2271: {
2272: if (s->pw == NULL)
2273: error("no user for session %d", s->self);
2274: else
2275: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2276: }
2277:
2278: int
2279: session_setup_x11fwd(Session *s)
2280: {
2281: struct stat st;
1.109 stevesk 2282: char display[512], auth_display[512];
1.272 djm 2283: char hostname[NI_MAXHOST];
1.184 djm 2284: u_int i;
1.81 markus 2285:
2286: if (no_x11_forwarding_flag) {
2287: packet_send_debug("X11 forwarding disabled in user configuration file.");
2288: return 0;
2289: }
2290: if (!options.x11_forwarding) {
2291: debug("X11 forwarding disabled in server configuration file.");
2292: return 0;
2293: }
1.275 djm 2294: if (options.xauth_location == NULL ||
1.81 markus 2295: (stat(options.xauth_location, &st) == -1)) {
2296: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2297: return 0;
2298: }
2299: if (options.use_login) {
2300: packet_send_debug("X11 forwarding disabled; "
2301: "not compatible with UseLogin=yes.");
1.81 markus 2302: return 0;
2303: }
1.87 markus 2304: if (s->display != NULL) {
1.81 markus 2305: debug("X11 display already set.");
2306: return 0;
2307: }
1.140 deraadt 2308: if (x11_create_display_inet(options.x11_display_offset,
2309: options.x11_use_localhost, s->single_connection,
1.184 djm 2310: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2311: debug("x11_create_display_inet failed.");
1.81 markus 2312: return 0;
1.184 djm 2313: }
2314: for (i = 0; s->x11_chanids[i] != -1; i++) {
2315: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2316: session_close_single_x11, 0);
1.81 markus 2317: }
1.109 stevesk 2318:
2319: /* Set up a suitable value for the DISPLAY variable. */
2320: if (gethostname(hostname, sizeof(hostname)) < 0)
2321: fatal("gethostname: %.100s", strerror(errno));
2322: /*
2323: * auth_display must be used as the displayname when the
2324: * authorization entry is added with xauth(1). This will be
2325: * different than the DISPLAY string for localhost displays.
2326: */
1.119 stevesk 2327: if (options.x11_use_localhost) {
1.140 deraadt 2328: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2329: s->display_number, s->screen);
1.140 deraadt 2330: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2331: s->display_number, s->screen);
1.109 stevesk 2332: s->display = xstrdup(display);
1.118 stevesk 2333: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2334: } else {
1.140 deraadt 2335: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2336: s->display_number, s->screen);
2337: s->display = xstrdup(display);
1.118 stevesk 2338: s->auth_display = xstrdup(display);
1.109 stevesk 2339: }
2340:
1.81 markus 2341: return 1;
1.2 markus 2342: }
2343:
1.94 itojun 2344: static void
1.49 markus 2345: do_authenticated2(Authctxt *authctxt)
1.2 markus 2346: {
1.97 markus 2347: server_loop2(authctxt);
1.165 markus 2348: }
2349:
2350: void
2351: do_cleanup(Authctxt *authctxt)
2352: {
2353: static int called = 0;
2354:
2355: debug("do_cleanup");
2356:
2357: /* no cleanup if we're in the child for login shell */
2358: if (is_child)
2359: return;
2360:
2361: /* avoid double cleanup */
2362: if (called)
2363: return;
2364: called = 1;
2365:
1.218 markus 2366: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2367: return;
2368: #ifdef KRB5
2369: if (options.kerberos_ticket_cleanup &&
2370: authctxt->krb5_ctx)
2371: krb5_cleanup_proc(authctxt);
1.161 markus 2372: #endif
1.165 markus 2373:
2374: #ifdef GSSAPI
2375: if (compat20 && options.gss_cleanup_creds)
2376: ssh_gssapi_cleanup_creds();
2377: #endif
2378:
2379: /* remove agent socket */
2380: auth_sock_cleanup_proc(authctxt->pw);
2381:
2382: /*
2383: * Cleanup ptys/utmp only if privsep is disabled,
2384: * or if running in monitor.
2385: */
2386: if (!use_privsep || mm_is_monitor())
2387: session_destroy_all(session_pty_cleanup2);
1.1 markus 2388: }
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