Annotation of src/usr.bin/ssh/session.c, Revision 1.277.2.1
1.277.2.1! djm 1: /* $OpenBSD: session.c,v 1.277 2015/01/16 06:40:12 deraadt 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:
1.277.2.1! 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;
146:
1.136 markus 147: /* Name and directory of socket for authentication agent forwarding. */
148: static char *auth_sock_name = NULL;
149: static char *auth_sock_dir = NULL;
150:
151: /* removes the agent forwarding socket */
152:
153: static void
1.165 markus 154: auth_sock_cleanup_proc(struct passwd *pw)
1.136 markus 155: {
156: if (auth_sock_name != NULL) {
157: temporarily_use_uid(pw);
158: unlink(auth_sock_name);
159: rmdir(auth_sock_dir);
160: auth_sock_name = NULL;
161: restore_uid();
162: }
163: }
164:
165: static int
166: auth_input_request_forwarding(struct passwd * pw)
167: {
168: Channel *nc;
1.237 djm 169: int sock = -1;
1.136 markus 170:
171: if (auth_sock_name != NULL) {
172: error("authentication forwarding requested twice.");
173: return 0;
174: }
175:
176: /* Temporarily drop privileged uid for mkdir/bind. */
177: temporarily_use_uid(pw);
178:
179: /* Allocate a buffer for the socket name, and format the name. */
1.237 djm 180: auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
1.136 markus 181:
182: /* Create private directory for socket */
183: if (mkdtemp(auth_sock_dir) == NULL) {
184: packet_send_debug("Agent forwarding disabled: "
185: "mkdtemp() failed: %.100s", strerror(errno));
186: restore_uid();
1.265 djm 187: free(auth_sock_dir);
1.136 markus 188: auth_sock_dir = NULL;
1.237 djm 189: goto authsock_err;
1.136 markus 190: }
1.237 djm 191:
192: xasprintf(&auth_sock_name, "%s/agent.%ld",
193: auth_sock_dir, (long) getpid());
1.136 markus 194:
1.274 millert 195: /* Start a Unix listener on auth_sock_name. */
196: sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0);
1.136 markus 197:
198: /* Restore the privileged uid. */
199: restore_uid();
200:
1.274 millert 201: /* Check for socket/bind/listen failure. */
202: if (sock < 0)
1.237 djm 203: goto authsock_err;
1.136 markus 204:
205: /* Allocate a channel for the authentication agent socket. */
206: nc = channel_new("auth socket",
207: SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
208: CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1.156 markus 209: 0, "auth socket", 1);
1.245 djm 210: nc->path = xstrdup(auth_sock_name);
1.136 markus 211: return 1;
1.237 djm 212:
213: authsock_err:
1.265 djm 214: free(auth_sock_name);
1.237 djm 215: if (auth_sock_dir != NULL) {
216: rmdir(auth_sock_dir);
1.265 djm 217: free(auth_sock_dir);
1.237 djm 218: }
219: if (sock != -1)
220: close(sock);
221: auth_sock_name = NULL;
222: auth_sock_dir = NULL;
223: return 0;
1.136 markus 224: }
225:
1.179 dtucker 226: static void
227: display_loginmsg(void)
228: {
1.183 djm 229: if (buffer_len(&loginmsg) > 0) {
230: buffer_append(&loginmsg, "\0", 1);
231: printf("%s", (char *)buffer_ptr(&loginmsg));
232: buffer_clear(&loginmsg);
233: }
1.179 dtucker 234: }
1.136 markus 235:
1.65 markus 236: void
237: do_authenticated(Authctxt *authctxt)
238: {
1.153 markus 239: setproctitle("%s", authctxt->pw->pw_name);
240:
1.65 markus 241: /* setup the channel layer */
1.274 millert 242: /* XXX - streamlocal? */
1.261 djm 243: if (no_port_forwarding_flag ||
244: (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
245: channel_disable_adm_local_opens();
246: else
1.65 markus 247: channel_permit_all_opens();
1.252 dtucker 248:
249: auth_debug_send();
1.65 markus 250:
251: if (compat20)
252: do_authenticated2(authctxt);
253: else
254: do_authenticated1(authctxt);
1.79 markus 255:
1.165 markus 256: do_cleanup(authctxt);
1.65 markus 257: }
258:
1.277.2.1! djm 259: /* Check untrusted xauth strings for metacharacters */
! 260: static int
! 261: xauth_valid_string(const char *s)
! 262: {
! 263: size_t i;
! 264:
! 265: for (i = 0; s[i] != '\0'; i++) {
! 266: if (!isalnum((u_char)s[i]) &&
! 267: s[i] != '.' && s[i] != ':' && s[i] != '/' &&
! 268: s[i] != '-' && s[i] != '_')
! 269: return 0;
! 270: }
! 271: return 1;
! 272: }
! 273:
1.1 markus 274: /*
275: * Prepares for an interactive session. This is called after the user has
276: * been successfully authenticated. During this message exchange, pseudo
277: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
278: * are requested, etc.
279: */
1.94 itojun 280: static void
1.65 markus 281: do_authenticated1(Authctxt *authctxt)
1.1 markus 282: {
283: Session *s;
1.65 markus 284: char *command;
1.117 markus 285: int success, type, screen_flag;
1.139 deraadt 286: int enable_compression_after_reply = 0;
287: u_int proto_len, data_len, dlen, compression_level = 0;
1.1 markus 288:
1.61 markus 289: s = session_new();
1.181 markus 290: if (s == NULL) {
291: error("no more sessions");
292: return;
293: }
1.96 dugsong 294: s->authctxt = authctxt;
1.65 markus 295: s->pw = authctxt->pw;
1.28 millert 296:
1.1 markus 297: /*
298: * We stay in this loop until the client requests to execute a shell
299: * or a command.
300: */
301: for (;;) {
1.65 markus 302: success = 0;
1.1 markus 303:
304: /* Get a packet from the client. */
1.117 markus 305: type = packet_read();
1.1 markus 306:
307: /* Process the packet. */
308: switch (type) {
309: case SSH_CMSG_REQUEST_COMPRESSION:
310: compression_level = packet_get_int();
1.116 markus 311: packet_check_eom();
1.1 markus 312: if (compression_level < 1 || compression_level > 9) {
1.180 markus 313: packet_send_debug("Received invalid compression level %d.",
1.112 deraadt 314: compression_level);
1.138 markus 315: break;
316: }
1.186 markus 317: if (options.compression == COMP_NONE) {
1.138 markus 318: debug2("compression disabled");
1.1 markus 319: break;
320: }
321: /* Enable compression after we have responded with SUCCESS. */
322: enable_compression_after_reply = 1;
323: success = 1;
324: break;
325:
326: case SSH_CMSG_REQUEST_PTY:
1.86 markus 327: success = session_pty_req(s);
1.1 markus 328: break;
329:
330: case SSH_CMSG_X11_REQUEST_FORWARDING:
331: s->auth_proto = packet_get_string(&proto_len);
332: s->auth_data = packet_get_string(&data_len);
333:
1.57 markus 334: screen_flag = packet_get_protocol_flags() &
335: SSH_PROTOFLAG_SCREEN_NUMBER;
336: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
337:
338: if (packet_remaining() == 4) {
339: if (!screen_flag)
340: debug2("Buggy client: "
341: "X11 screen flag missing");
1.1 markus 342: s->screen = packet_get_int();
1.56 markus 343: } else {
1.1 markus 344: s->screen = 0;
1.56 markus 345: }
1.116 markus 346: packet_check_eom();
1.277.2.1! djm 347: if (xauth_valid_string(s->auth_proto) &&
! 348: xauth_valid_string(s->auth_data))
! 349: success = session_setup_x11fwd(s);
! 350: else {
! 351: success = 0;
! 352: error("Invalid X11 forwarding data");
! 353: }
1.81 markus 354: if (!success) {
1.265 djm 355: free(s->auth_proto);
356: free(s->auth_data);
1.84 markus 357: s->auth_proto = NULL;
358: s->auth_data = NULL;
1.1 markus 359: }
360: break;
361:
362: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1.235 pyr 363: if (!options.allow_agent_forwarding ||
364: no_agent_forwarding_flag || compat13) {
1.1 markus 365: debug("Authentication agent forwarding not permitted for this authentication.");
366: break;
367: }
368: debug("Received authentication agent forwarding request.");
1.65 markus 369: success = auth_input_request_forwarding(s->pw);
1.1 markus 370: break;
371:
372: case SSH_CMSG_PORT_FORWARD_REQUEST:
373: if (no_port_forwarding_flag) {
374: debug("Port forwarding not permitted for this authentication.");
1.39 markus 375: break;
376: }
1.261 djm 377: if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
1.39 markus 378: debug("Port forwarding not permitted.");
1.1 markus 379: break;
380: }
381: debug("Received TCP/IP port forwarding request.");
1.208 markus 382: if (channel_input_port_forward_request(s->pw->pw_uid == 0,
1.274 millert 383: &options.fwd_opts) < 0) {
1.208 markus 384: debug("Port forwarding failed.");
385: break;
386: }
1.1 markus 387: success = 1;
388: break;
389:
390: case SSH_CMSG_MAX_PACKET_SIZE:
391: if (packet_set_maxsize(packet_get_int()) > 0)
392: success = 1;
393: break;
394:
395: case SSH_CMSG_EXEC_SHELL:
396: case SSH_CMSG_EXEC_CMD:
397: if (type == SSH_CMSG_EXEC_CMD) {
398: command = packet_get_string(&dlen);
399: debug("Exec command '%.500s'", command);
1.237 djm 400: if (do_exec(s, command) != 0)
401: packet_disconnect(
402: "command execution failed");
1.265 djm 403: free(command);
1.1 markus 404: } else {
1.237 djm 405: if (do_exec(s, NULL) != 0)
406: packet_disconnect(
407: "shell execution failed");
1.1 markus 408: }
1.116 markus 409: packet_check_eom();
1.82 markus 410: session_close(s);
1.1 markus 411: return;
412:
413: default:
414: /*
415: * Any unknown messages in this phase are ignored,
416: * and a failure message is returned.
417: */
1.155 itojun 418: logit("Unknown packet type received after authentication: %d", type);
1.1 markus 419: }
420: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
421: packet_send();
422: packet_write_wait();
423:
424: /* Enable compression now that we have replied if appropriate. */
425: if (enable_compression_after_reply) {
426: enable_compression_after_reply = 0;
427: packet_start_compression(compression_level);
428: }
429: }
430: }
431:
1.269 dtucker 432: #define USE_PIPES 1
1.1 markus 433: /*
434: * This is called to fork and execute a command when we have no tty. This
435: * will call do_child from the child, and server_loop from the parent after
436: * setting up file descriptors and such.
437: */
1.237 djm 438: int
1.63 markus 439: do_exec_no_pty(Session *s, const char *command)
1.1 markus 440: {
1.137 mpech 441: pid_t pid;
1.238 markus 442: #ifdef USE_PIPES
443: int pin[2], pout[2], perr[2];
444:
1.253 djm 445: if (s == NULL)
446: fatal("do_exec_no_pty: no session");
447:
1.238 markus 448: /* Allocate pipes for communicating with the program. */
449: if (pipe(pin) < 0) {
450: error("%s: pipe in: %.100s", __func__, strerror(errno));
451: return -1;
452: }
453: if (pipe(pout) < 0) {
454: error("%s: pipe out: %.100s", __func__, strerror(errno));
455: close(pin[0]);
456: close(pin[1]);
457: return -1;
458: }
1.256 djm 459: if (pipe(perr) < 0) {
460: error("%s: pipe err: %.100s", __func__,
461: strerror(errno));
462: close(pin[0]);
463: close(pin[1]);
464: close(pout[0]);
465: close(pout[1]);
466: return -1;
1.238 markus 467: }
468: #else
1.237 djm 469: int inout[2], err[2];
1.1 markus 470:
1.253 djm 471: if (s == NULL)
472: fatal("do_exec_no_pty: no session");
473:
1.1 markus 474: /* Uses socket pairs to communicate with the program. */
1.237 djm 475: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
476: error("%s: socketpair #1: %.100s", __func__, strerror(errno));
477: return -1;
478: }
1.256 djm 479: if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
480: error("%s: socketpair #2: %.100s", __func__,
481: strerror(errno));
482: close(inout[0]);
483: close(inout[1]);
484: return -1;
1.237 djm 485: }
1.238 markus 486: #endif
1.237 djm 487:
1.9 markus 488: session_proctitle(s);
1.1 markus 489:
490: /* Fork the child. */
1.237 djm 491: switch ((pid = fork())) {
492: case -1:
493: error("%s: fork: %.100s", __func__, strerror(errno));
1.238 markus 494: #ifdef USE_PIPES
495: close(pin[0]);
496: close(pin[1]);
497: close(pout[0]);
498: close(pout[1]);
1.256 djm 499: close(perr[0]);
1.238 markus 500: close(perr[1]);
501: #else
1.237 djm 502: close(inout[0]);
503: close(inout[1]);
504: close(err[0]);
1.256 djm 505: close(err[1]);
1.238 markus 506: #endif
1.237 djm 507: return -1;
508: case 0:
1.165 markus 509: is_child = 1;
1.144 markus 510:
1.1 markus 511: /* Child. Reinitialize the log since the pid has changed. */
1.237 djm 512: log_init(__progname, options.log_level,
513: options.log_facility, log_stderr);
1.1 markus 514:
515: /*
516: * Create a new session and process group since the 4.4BSD
517: * setlogin() affects the entire process group.
518: */
519: if (setsid() < 0)
520: error("setsid failed: %.100s", strerror(errno));
521:
1.238 markus 522: #ifdef USE_PIPES
523: /*
524: * Redirect stdin. We close the parent side of the socket
525: * pair, and make the child side the standard input.
526: */
527: close(pin[1]);
528: if (dup2(pin[0], 0) < 0)
529: perror("dup2 stdin");
530: close(pin[0]);
531:
532: /* Redirect stdout. */
533: close(pout[0]);
534: if (dup2(pout[1], 1) < 0)
535: perror("dup2 stdout");
536: close(pout[1]);
537:
538: /* Redirect stderr. */
1.256 djm 539: close(perr[0]);
1.238 markus 540: if (dup2(perr[1], 2) < 0)
541: perror("dup2 stderr");
542: close(perr[1]);
543: #else
1.1 markus 544: /*
545: * Redirect stdin, stdout, and stderr. Stdin and stdout will
546: * use the same socket, as some programs (particularly rdist)
547: * seem to depend on it.
548: */
549: close(inout[1]);
1.256 djm 550: close(err[1]);
1.1 markus 551: if (dup2(inout[0], 0) < 0) /* stdin */
552: perror("dup2 stdin");
1.237 djm 553: if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
1.1 markus 554: perror("dup2 stdout");
1.238 markus 555: close(inout[0]);
1.1 markus 556: if (dup2(err[0], 2) < 0) /* stderr */
557: perror("dup2 stderr");
1.238 markus 558: close(err[0]);
559: #endif
1.1 markus 560:
561: /* Do processing for the child (exec command etc). */
1.60 markus 562: do_child(s, command);
1.1 markus 563: /* NOTREACHED */
1.237 djm 564: default:
565: break;
1.1 markus 566: }
1.237 djm 567:
1.1 markus 568: s->pid = pid;
1.47 markus 569: /* Set interactive/non-interactive mode. */
1.257 djm 570: packet_set_interactive(s->display != NULL,
571: options.ip_qos_interactive, options.ip_qos_bulk);
1.1 markus 572:
1.238 markus 573: #ifdef USE_PIPES
574: /* We are the parent. Close the child sides of the pipes. */
575: close(pin[0]);
576: close(pout[1]);
577: close(perr[1]);
578:
579: if (compat20) {
1.256 djm 580: session_set_fds(s, pin[1], pout[0], perr[0],
581: s->is_subsystem, 0);
1.238 markus 582: } else {
583: /* Enter the interactive session. */
584: server_loop(pid, pin[1], pout[0], perr[0]);
585: /* server_loop has closed pin[1], pout[0], and perr[0]. */
586: }
587: #else
1.1 markus 588: /* We are the parent. Close the child sides of the socket pairs. */
589: close(inout[0]);
590: close(err[0]);
591:
592: /*
593: * Enter the interactive session. Note: server_loop must be able to
594: * handle the case that fdin and fdout are the same.
595: */
1.2 markus 596: if (compat20) {
1.256 djm 597: session_set_fds(s, inout[1], inout[1], err[1],
598: s->is_subsystem, 0);
1.2 markus 599: } else {
600: server_loop(pid, inout[1], inout[1], err[1]);
601: /* server_loop has closed inout[1] and err[1]. */
602: }
1.238 markus 603: #endif
1.237 djm 604: return 0;
1.1 markus 605: }
606:
607: /*
608: * This is called to fork and execute a command when we have a tty. This
609: * will call do_child from the child, and server_loop from the parent after
610: * setting up file descriptors, controlling tty, updating wtmp, utmp,
611: * lastlog, and other such operations.
612: */
1.237 djm 613: int
1.63 markus 614: do_exec_pty(Session *s, const char *command)
1.1 markus 615: {
616: int fdout, ptyfd, ttyfd, ptymaster;
617: pid_t pid;
618:
619: if (s == NULL)
620: fatal("do_exec_pty: no session");
621: ptyfd = s->ptyfd;
622: ttyfd = s->ttyfd;
623:
1.237 djm 624: /*
625: * Create another descriptor of the pty master side for use as the
626: * standard input. We could use the original descriptor, but this
627: * simplifies code in server_loop. The descriptor is bidirectional.
628: * Do this before forking (and cleanup in the child) so as to
629: * detect and gracefully fail out-of-fd conditions.
630: */
631: if ((fdout = dup(ptyfd)) < 0) {
632: error("%s: dup #1: %s", __func__, strerror(errno));
633: close(ttyfd);
634: close(ptyfd);
635: return -1;
636: }
637: /* we keep a reference to the pty master */
638: if ((ptymaster = dup(ptyfd)) < 0) {
639: error("%s: dup #2: %s", __func__, strerror(errno));
640: close(ttyfd);
641: close(ptyfd);
642: close(fdout);
643: return -1;
644: }
645:
1.1 markus 646: /* Fork the child. */
1.237 djm 647: switch ((pid = fork())) {
648: case -1:
649: error("%s: fork: %.100s", __func__, strerror(errno));
650: close(fdout);
651: close(ptymaster);
652: close(ttyfd);
653: close(ptyfd);
654: return -1;
655: case 0:
1.165 markus 656: is_child = 1;
1.97 markus 657:
1.237 djm 658: close(fdout);
659: close(ptymaster);
660:
1.24 markus 661: /* Child. Reinitialize the log because the pid has changed. */
1.237 djm 662: log_init(__progname, options.log_level,
663: options.log_facility, log_stderr);
1.1 markus 664: /* Close the master side of the pseudo tty. */
665: close(ptyfd);
666:
667: /* Make the pseudo tty our controlling tty. */
668: pty_make_controlling_tty(&ttyfd, s->tty);
669:
1.103 markus 670: /* Redirect stdin/stdout/stderr from the pseudo tty. */
671: if (dup2(ttyfd, 0) < 0)
672: error("dup2 stdin: %s", strerror(errno));
673: if (dup2(ttyfd, 1) < 0)
674: error("dup2 stdout: %s", strerror(errno));
675: if (dup2(ttyfd, 2) < 0)
676: error("dup2 stderr: %s", strerror(errno));
1.1 markus 677:
678: /* Close the extra descriptor for the pseudo tty. */
679: close(ttyfd);
680:
1.24 markus 681: /* record login, etc. similar to login(1) */
1.41 markus 682: if (!(options.use_login && command == NULL))
683: do_login(s, command);
1.228 djm 684:
1.237 djm 685: /*
686: * Do common processing for the child, such as execing
687: * the command.
688: */
1.60 markus 689: do_child(s, command);
1.1 markus 690: /* NOTREACHED */
1.237 djm 691: default:
692: break;
1.1 markus 693: }
694: s->pid = pid;
695:
696: /* Parent. Close the slave side of the pseudo tty. */
697: close(ttyfd);
698:
1.237 djm 699: /* Enter interactive session. */
1.1 markus 700: s->ptymaster = ptymaster;
1.257 djm 701: packet_set_interactive(1,
702: options.ip_qos_interactive, options.ip_qos_bulk);
1.2 markus 703: if (compat20) {
1.256 djm 704: session_set_fds(s, ptyfd, fdout, -1, 1, 1);
1.2 markus 705: } else {
706: server_loop(pid, ptyfd, fdout, -1);
707: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 708: }
1.237 djm 709: return 0;
1.24 markus 710: }
711:
1.90 markus 712: /*
713: * This is called to fork and execute a command. If another command is
714: * to be forced, execute that instead.
715: */
1.237 djm 716: int
1.90 markus 717: do_exec(Session *s, const char *command)
718: {
1.237 djm 719: int ret;
1.267 djm 720: const char *forced = NULL;
721: char session_type[1024], *tty = NULL;
1.237 djm 722:
1.210 dtucker 723: if (options.adm_forced_command) {
724: original_command = command;
725: command = options.adm_forced_command;
1.267 djm 726: forced = "(config)";
1.210 dtucker 727: } else if (forced_command) {
1.90 markus 728: original_command = command;
729: command = forced_command;
1.267 djm 730: forced = "(key-option)";
731: }
732: if (forced != NULL) {
1.248 djm 733: if (IS_INTERNAL_SFTP(command)) {
734: s->is_subsystem = s->is_subsystem ?
735: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
736: } else if (s->is_subsystem)
1.225 markus 737: s->is_subsystem = SUBSYSTEM_EXT;
1.267 djm 738: snprintf(session_type, sizeof(session_type),
739: "forced-command %s '%.900s'", forced, command);
740: } else if (s->is_subsystem) {
741: snprintf(session_type, sizeof(session_type),
742: "subsystem '%.900s'", s->subsys);
743: } else if (command == NULL) {
744: snprintf(session_type, sizeof(session_type), "shell");
745: } else {
746: /* NB. we don't log unforced commands to preserve privacy */
747: snprintf(session_type, sizeof(session_type), "command");
1.90 markus 748: }
1.163 markus 749:
1.267 djm 750: if (s->ttyfd != -1) {
751: tty = s->tty;
752: if (strncmp(tty, "/dev/", 5) == 0)
753: tty += 5;
754: }
755:
756: verbose("Starting session: %s%s%s for %s from %.200s port %d",
757: session_type,
758: tty == NULL ? "" : " on ",
759: tty == NULL ? "" : tty,
760: s->pw->pw_name,
761: get_remote_ipaddr(),
762: get_remote_port());
763:
1.163 markus 764: #ifdef GSSAPI
765: if (options.gss_authentication) {
766: temporarily_use_uid(s->pw);
767: ssh_gssapi_storecreds();
768: restore_uid();
769: }
770: #endif
1.90 markus 771: if (s->ttyfd != -1)
1.237 djm 772: ret = do_exec_pty(s, command);
1.90 markus 773: else
1.237 djm 774: ret = do_exec_no_pty(s, command);
1.90 markus 775:
1.92 markus 776: original_command = NULL;
1.179 dtucker 777:
778: /*
779: * Clear loginmsg: it's the child's responsibility to display
780: * it to the user, otherwise multiple sessions may accumulate
781: * multiple copies of the login messages.
782: */
783: buffer_clear(&loginmsg);
1.237 djm 784:
785: return ret;
1.90 markus 786: }
787:
788:
1.24 markus 789: /* administrative, login(1)-like work */
790: void
1.41 markus 791: do_login(Session *s, const char *command)
1.24 markus 792: {
793: socklen_t fromlen;
794: struct sockaddr_storage from;
795: struct passwd * pw = s->pw;
796: pid_t pid = getpid();
797:
798: /*
799: * Get IP address of client. If the connection is not a socket, let
800: * the address be 0.0.0.0.
801: */
802: memset(&from, 0, sizeof(from));
1.148 stevesk 803: fromlen = sizeof(from);
1.24 markus 804: if (packet_connection_is_on_socket()) {
805: if (getpeername(packet_get_connection_in(),
1.200 deraadt 806: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 807: debug("getpeername: %.100s", strerror(errno));
1.165 markus 808: cleanup_exit(255);
1.24 markus 809: }
810: }
1.25 markus 811:
1.24 markus 812: /* Record that there was a login on that tty from the remote host. */
1.133 markus 813: if (!use_privsep)
814: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
815: get_remote_name_or_ip(utmp_len,
1.158 markus 816: options.use_dns),
1.148 stevesk 817: (struct sockaddr *)&from, fromlen);
1.24 markus 818:
1.73 djm 819: if (check_quietlogin(s, command))
1.24 markus 820: return;
1.73 djm 821:
1.179 dtucker 822: display_loginmsg();
1.73 djm 823:
824: do_motd();
825: }
826:
827: /*
828: * Display the message of the day.
829: */
830: void
831: do_motd(void)
832: {
833: FILE *f;
834: char buf[256];
835:
1.24 markus 836: if (options.print_motd) {
1.28 millert 837: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
838: "/etc/motd"), "r");
1.24 markus 839: if (f) {
840: while (fgets(buf, sizeof(buf), f))
841: fputs(buf, stdout);
842: fclose(f);
843: }
1.2 markus 844: }
1.73 djm 845: }
846:
847:
848: /*
849: * Check for quiet login, either .hushlogin or command given.
850: */
851: int
852: check_quietlogin(Session *s, const char *command)
853: {
854: char buf[256];
1.96 dugsong 855: struct passwd *pw = s->pw;
1.73 djm 856: struct stat st;
857:
858: /* Return 1 if .hushlogin exists or a command given. */
859: if (command != NULL)
860: return 1;
861: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
862: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
863: return 1;
864: return 0;
1.1 markus 865: }
866:
867: /*
868: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 869: * already exists, its value is overridden.
1.1 markus 870: */
1.161 markus 871: void
1.45 markus 872: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 873: const char *value)
1.1 markus 874: {
1.164 markus 875: char **env;
876: u_int envsize;
1.45 markus 877: u_int i, namelen;
1.1 markus 878:
1.271 djm 879: if (strchr(name, '=') != NULL) {
880: error("Invalid environment variable \"%.100s\"", name);
881: return;
882: }
883:
1.1 markus 884: /*
885: * Find the slot where the value should be stored. If the variable
886: * already exists, we reuse the slot; otherwise we append a new slot
887: * at the end of the array, expanding if necessary.
888: */
889: env = *envp;
890: namelen = strlen(name);
891: for (i = 0; env[i]; i++)
892: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
893: break;
894: if (env[i]) {
895: /* Reuse the slot. */
1.265 djm 896: free(env[i]);
1.1 markus 897: } else {
898: /* New variable. Expand if necessary. */
1.164 markus 899: envsize = *envsizep;
900: if (i >= envsize - 1) {
901: if (envsize >= 1000)
902: fatal("child_set_env: too many env vars");
903: envsize += 50;
1.201 djm 904: env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1.164 markus 905: *envsizep = envsize;
1.1 markus 906: }
907: /* Need to set the NULL pointer at end of array beyond the new slot. */
908: env[i + 1] = NULL;
909: }
910:
911: /* Allocate space and format the variable in the appropriate slot. */
912: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
913: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
914: }
915:
916: /*
917: * Reads environment variables from the given file and adds/overrides them
918: * into the environment. If the file does not exist, this does nothing.
919: * Otherwise, it must consist of empty lines, comments (line starts with '#')
920: * and assignments of the form name=value. No other forms are allowed.
921: */
1.94 itojun 922: static void
1.45 markus 923: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 924: const char *filename)
1.1 markus 925: {
926: FILE *f;
927: char buf[4096];
928: char *cp, *value;
1.142 deraadt 929: u_int lineno = 0;
1.1 markus 930:
931: f = fopen(filename, "r");
932: if (!f)
933: return;
934:
935: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 936: if (++lineno > 1000)
937: fatal("Too many lines in environment file %s", filename);
1.1 markus 938: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
939: ;
940: if (!*cp || *cp == '#' || *cp == '\n')
941: continue;
1.224 gilles 942:
943: cp[strcspn(cp, "\n")] = '\0';
944:
1.1 markus 945: value = strchr(cp, '=');
946: if (value == NULL) {
1.142 deraadt 947: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
948: filename);
1.1 markus 949: continue;
950: }
1.14 deraadt 951: /*
952: * Replace the equals sign by nul, and advance value to
953: * the value string.
954: */
1.1 markus 955: *value = '\0';
956: value++;
957: child_set_env(env, envsize, cp, value);
958: }
959: fclose(f);
960: }
961:
1.127 markus 962: static char **
963: do_setup_env(Session *s, const char *shell)
1.1 markus 964: {
965: char buf[256];
1.127 markus 966: u_int i, envsize;
1.154 markus 967: char **env, *laddr;
1.127 markus 968: struct passwd *pw = s->pw;
1.1 markus 969:
970: /* Initialize the environment. */
971: envsize = 100;
1.220 djm 972: env = xcalloc(envsize, sizeof(char *));
1.1 markus 973: env[0] = NULL;
974:
1.161 markus 975: #ifdef GSSAPI
1.168 djm 976: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 977: * the childs environment as they see fit
978: */
979: ssh_gssapi_do_child(&env, &envsize);
980: #endif
981:
1.1 markus 982: if (!options.use_login) {
983: /* Set basic environment. */
1.173 djm 984: for (i = 0; i < s->num_env; i++)
1.178 deraadt 985: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 986: s->env[i].val);
987:
1.1 markus 988: child_set_env(&env, &envsize, "USER", pw->pw_name);
989: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
990: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 991: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
992: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
993: else
994: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 995:
996: snprintf(buf, sizeof buf, "%.200s/%.50s",
997: _PATH_MAILDIR, pw->pw_name);
998: child_set_env(&env, &envsize, "MAIL", buf);
999:
1000: /* Normal systems set SHELL by default. */
1001: child_set_env(&env, &envsize, "SHELL", shell);
1002: }
1003: if (getenv("TZ"))
1004: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1005:
1006: /* Set custom environment options from RSA authentication. */
1.110 markus 1007: if (!options.use_login) {
1008: while (custom_environment) {
1009: struct envstring *ce = custom_environment;
1.143 deraadt 1010: char *str = ce->s;
1.127 markus 1011:
1.143 deraadt 1012: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 1013: ;
1.143 deraadt 1014: if (str[i] == '=') {
1015: str[i] = 0;
1016: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 1017: }
1018: custom_environment = ce->next;
1.265 djm 1019: free(ce->s);
1020: free(ce);
1.1 markus 1021: }
1022: }
1023:
1.149 stevesk 1024: /* SSH_CLIENT deprecated */
1.1 markus 1025: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 1026: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 1027: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1028:
1.154 markus 1029: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1030: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 1031: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1.265 djm 1032: free(laddr);
1.149 stevesk 1033: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1034:
1.60 markus 1035: if (s->ttyfd != -1)
1036: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1037: if (s->term)
1038: child_set_env(&env, &envsize, "TERM", s->term);
1039: if (s->display)
1040: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1041: if (original_command)
1042: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1043: original_command);
1.96 dugsong 1044: #ifdef KRB5
1045: if (s->authctxt->krb5_ticket_file)
1046: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1047: s->authctxt->krb5_ticket_file);
1.96 dugsong 1048: #endif
1.136 markus 1049: if (auth_sock_name != NULL)
1.1 markus 1050: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1051: auth_sock_name);
1.1 markus 1052:
1053: /* read $HOME/.ssh/environment. */
1.146 markus 1054: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1055: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1056: pw->pw_dir);
1.1 markus 1057: read_environment_file(&env, &envsize, buf);
1058: }
1059: if (debug_flag) {
1060: /* dump the environment */
1061: fprintf(stderr, "Environment:\n");
1062: for (i = 0; env[i]; i++)
1063: fprintf(stderr, " %.200s\n", env[i]);
1064: }
1.127 markus 1065: return env;
1066: }
1067:
1068: /*
1069: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1070: * first in this order).
1071: */
1072: static void
1073: do_rc_files(Session *s, const char *shell)
1074: {
1075: FILE *f = NULL;
1076: char cmd[1024];
1077: int do_xauth;
1078: struct stat st;
1079:
1080: do_xauth =
1081: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1082:
1.231 djm 1083: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1084: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.273 djm 1085: !no_user_rc && options.permit_user_rc &&
1086: stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1087: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1088: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1089: if (debug_flag)
1090: fprintf(stderr, "Running %s\n", cmd);
1091: f = popen(cmd, "w");
1092: if (f) {
1093: if (do_xauth)
1094: fprintf(f, "%s %s\n", s->auth_proto,
1095: s->auth_data);
1096: pclose(f);
1097: } else
1098: fprintf(stderr, "Could not run %s\n",
1099: _PATH_SSH_USER_RC);
1100: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1101: if (debug_flag)
1102: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1103: _PATH_SSH_SYSTEM_RC);
1104: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1105: if (f) {
1106: if (do_xauth)
1107: fprintf(f, "%s %s\n", s->auth_proto,
1108: s->auth_data);
1109: pclose(f);
1110: } else
1111: fprintf(stderr, "Could not run %s\n",
1112: _PATH_SSH_SYSTEM_RC);
1113: } else if (do_xauth && options.xauth_location != NULL) {
1114: /* Add authority data to .Xauthority if appropriate. */
1115: if (debug_flag) {
1116: fprintf(stderr,
1.151 stevesk 1117: "Running %.500s remove %.100s\n",
1.165 markus 1118: options.xauth_location, s->auth_display);
1.151 stevesk 1119: fprintf(stderr,
1120: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1121: options.xauth_location, s->auth_display,
1122: s->auth_proto, s->auth_data);
1123: }
1124: snprintf(cmd, sizeof cmd, "%s -q -",
1125: options.xauth_location);
1126: f = popen(cmd, "w");
1127: if (f) {
1.151 stevesk 1128: fprintf(f, "remove %s\n",
1129: s->auth_display);
1.127 markus 1130: fprintf(f, "add %s %s %s\n",
1131: s->auth_display, s->auth_proto,
1132: s->auth_data);
1133: pclose(f);
1134: } else {
1135: fprintf(stderr, "Could not run %s\n",
1136: cmd);
1137: }
1138: }
1139: }
1140:
1141: static void
1142: do_nologin(struct passwd *pw)
1143: {
1144: FILE *f = NULL;
1.251 dtucker 1145: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1146: struct stat sb;
1.127 markus 1147:
1.260 guenther 1148: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1149: return;
1150: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1151:
1152: if (stat(nl, &sb) == -1) {
1153: if (nl != def_nl)
1.265 djm 1154: free(nl);
1.251 dtucker 1155: return;
1156: }
1157:
1158: /* /etc/nologin exists. Print its contents if we can and exit. */
1159: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1160: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1161: while (fgets(buf, sizeof(buf), f))
1162: fputs(buf, stderr);
1163: fclose(f);
1164: }
1.251 dtucker 1165: exit(254);
1.127 markus 1166: }
1167:
1.226 djm 1168: /*
1169: * Chroot into a directory after checking it for safety: all path components
1170: * must be root-owned directories with strict permissions.
1171: */
1172: static void
1173: safely_chroot(const char *path, uid_t uid)
1174: {
1175: const char *cp;
1.277 deraadt 1176: char component[PATH_MAX];
1.226 djm 1177: struct stat st;
1178:
1179: if (*path != '/')
1180: fatal("chroot path does not begin at root");
1181: if (strlen(path) >= sizeof(component))
1182: fatal("chroot path too long");
1183:
1184: /*
1185: * Descend the path, checking that each component is a
1186: * root-owned directory with strict permissions.
1187: */
1188: for (cp = path; cp != NULL;) {
1189: if ((cp = strchr(cp, '/')) == NULL)
1190: strlcpy(component, path, sizeof(component));
1191: else {
1192: cp++;
1193: memcpy(component, path, cp - path);
1194: component[cp - path] = '\0';
1195: }
1196:
1197: debug3("%s: checking '%s'", __func__, component);
1198:
1199: if (stat(component, &st) != 0)
1200: fatal("%s: stat(\"%s\"): %s", __func__,
1201: component, strerror(errno));
1202: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1203: fatal("bad ownership or modes for chroot "
1204: "directory %s\"%s\"",
1205: cp == NULL ? "" : "component ", component);
1206: if (!S_ISDIR(st.st_mode))
1207: fatal("chroot path %s\"%s\" is not a directory",
1208: cp == NULL ? "" : "component ", component);
1209:
1210: }
1211:
1212: if (chdir(path) == -1)
1213: fatal("Unable to chdir to chroot path \"%s\": "
1214: "%s", path, strerror(errno));
1215: if (chroot(path) == -1)
1216: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1217: if (chdir("/") == -1)
1218: fatal("%s: chdir(/) after chroot: %s",
1219: __func__, strerror(errno));
1220: verbose("Changed root directory to \"%s\"", path);
1221: }
1222:
1.127 markus 1223: /* Set login name, uid, gid, and groups. */
1.130 provos 1224: void
1.127 markus 1225: do_setusercontext(struct passwd *pw)
1226: {
1.227 djm 1227: char *chroot_path, *tmp;
1228:
1.127 markus 1229: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1230: /* Prepare groups */
1.127 markus 1231: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1232: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1233: perror("unable to set user context");
1234: exit(1);
1235: }
1.226 djm 1236:
1237: if (options.chroot_directory != NULL &&
1238: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1239: tmp = tilde_expand_filename(options.chroot_directory,
1240: pw->pw_uid);
1241: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1242: "u", pw->pw_name, (char *)NULL);
1.226 djm 1243: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1244: free(tmp);
1.226 djm 1245: free(chroot_path);
1.264 djm 1246: /* Make sure we don't attempt to chroot again */
1247: free(options.chroot_directory);
1248: options.chroot_directory = NULL;
1.226 djm 1249: }
1250:
1251: /* Set UID */
1252: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1253: perror("unable to set user context (setuser)");
1254: exit(1);
1255: }
1.264 djm 1256: } else if (options.chroot_directory != NULL &&
1257: strcasecmp(options.chroot_directory, "none") != 0) {
1258: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1259: }
1.264 djm 1260:
1.127 markus 1261: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1262: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1263: }
1264:
1.131 markus 1265: static void
1.172 markus 1266: do_pwchange(Session *s)
1267: {
1.179 dtucker 1268: fflush(NULL);
1.172 markus 1269: fprintf(stderr, "WARNING: Your password has expired.\n");
1270: if (s->ttyfd != -1) {
1.178 deraadt 1271: fprintf(stderr,
1.172 markus 1272: "You must change your password now and login again!\n");
1273: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1274: perror("passwd");
1275: } else {
1276: fprintf(stderr,
1277: "Password change required but no TTY available.\n");
1278: }
1279: exit(1);
1280: }
1281:
1282: static void
1.130 provos 1283: launch_login(struct passwd *pw, const char *hostname)
1284: {
1285: /* Launch login(1). */
1286:
1287: execl("/usr/bin/login", "login", "-h", hostname,
1288: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1289:
1290: /* Login couldn't be executed, die. */
1291:
1292: perror("login");
1293: exit(1);
1294: }
1295:
1.172 markus 1296: static void
1297: child_close_fds(void)
1298: {
1.276 djm 1299: extern int auth_sock;
1.266 markus 1300:
1.276 djm 1301: if (auth_sock != -1) {
1302: close(auth_sock);
1303: auth_sock = -1;
1.266 markus 1304: }
1305:
1.172 markus 1306: if (packet_get_connection_in() == packet_get_connection_out())
1307: close(packet_get_connection_in());
1308: else {
1309: close(packet_get_connection_in());
1310: close(packet_get_connection_out());
1311: }
1312: /*
1313: * Close all descriptors related to channels. They will still remain
1314: * open in the parent.
1315: */
1316: /* XXX better use close-on-exec? -markus */
1317: channel_close_all();
1318:
1319: /*
1320: * Close any extra file descriptors. Note that there may still be
1321: * descriptors left by system functions. They will be closed later.
1322: */
1323: endpwent();
1324:
1325: /*
1.188 djm 1326: * Close any extra open file descriptors so that we don't have them
1.172 markus 1327: * hanging around in clients. Note that we want to do this after
1328: * initgroups, because at least on Solaris 2.3 it leaves file
1329: * descriptors open.
1330: */
1.258 djm 1331: closefrom(STDERR_FILENO + 1);
1.172 markus 1332: }
1333:
1.127 markus 1334: /*
1335: * Performs common processing for the child, such as setting up the
1336: * environment, closing extra file descriptors, setting the user and group
1337: * ids, and executing the command or shell.
1338: */
1.225 markus 1339: #define ARGV_MAX 10
1.127 markus 1340: void
1341: do_child(Session *s, const char *command)
1342: {
1343: extern char **environ;
1344: char **env;
1.225 markus 1345: char *argv[ARGV_MAX];
1.127 markus 1346: const char *shell, *shell0, *hostname = NULL;
1347: struct passwd *pw = s->pw;
1.239 djm 1348: int r = 0;
1.127 markus 1349:
1350: /* remove hostkey from the child's memory */
1351: destroy_sensitive_data();
1352:
1.172 markus 1353: /* Force a password change */
1354: if (s->authctxt->force_pwchange) {
1355: do_setusercontext(pw);
1356: child_close_fds();
1357: do_pwchange(s);
1358: exit(1);
1359: }
1360:
1.127 markus 1361: /* login(1) is only called if we execute the login shell */
1362: if (options.use_login && command != NULL)
1363: options.use_login = 0;
1364:
1365: /*
1366: * Login(1) does this as well, and it needs uid 0 for the "-h"
1367: * switch, so we let login(1) to this for us.
1368: */
1369: if (!options.use_login) {
1370: do_nologin(pw);
1371: do_setusercontext(pw);
1372: }
1373:
1374: /*
1375: * Get the shell from the password data. An empty shell field is
1376: * legal, and means /bin/sh.
1377: */
1378: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1379:
1380: /*
1381: * Make sure $SHELL points to the shell from the password file,
1382: * even if shell is overridden from login.conf
1383: */
1384: env = do_setup_env(s, shell);
1385:
1.127 markus 1386: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1387:
1.26 millert 1388: /* we have to stash the hostname before we close our socket. */
1389: if (options.use_login)
1.70 stevesk 1390: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1391: options.use_dns);
1.1 markus 1392: /*
1393: * Close the connection descriptors; note that this is the child, and
1394: * the server will still have the socket open, and it is important
1395: * that we do not shutdown it. Note that the descriptors cannot be
1396: * closed before building the environment, as we call
1397: * get_remote_ipaddr there.
1398: */
1.172 markus 1399: child_close_fds();
1.1 markus 1400:
1401: /*
1.125 deraadt 1402: * Must take new environment into use so that .ssh/rc,
1403: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1404: */
1405: environ = env;
1.170 jakob 1406:
1407: #ifdef KRB5
1408: /*
1409: * At this point, we check to see if AFS is active and if we have
1410: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1411: * if we can (and need to) extend the ticket into an AFS token. If
1412: * we don't do this, we run into potential problems if the user's
1413: * home directory is in AFS and it's not world-readable.
1414: */
1415:
1416: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1417: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1418: char cell[64];
1419:
1420: debug("Getting AFS token");
1421:
1422: k_setpag();
1423:
1424: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1425: krb5_afslog(s->authctxt->krb5_ctx,
1426: s->authctxt->krb5_fwd_ccache, cell, NULL);
1427:
1428: krb5_afslog_home(s->authctxt->krb5_ctx,
1429: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1430: }
1431: #endif
1.104 markus 1432:
1.188 djm 1433: /* Change current directory to the user's home directory. */
1.104 markus 1434: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1435: /* Suppress missing homedir warning for chroot case */
1436: r = login_getcapbool(lc, "requirehome", 0);
1.254 djm 1437: if (r || options.chroot_directory == NULL ||
1438: strcasecmp(options.chroot_directory, "none") == 0)
1.239 djm 1439: fprintf(stderr, "Could not chdir to home "
1440: "directory %s: %s\n", pw->pw_dir,
1441: strerror(errno));
1442: if (r)
1.104 markus 1443: exit(1);
1444: }
1.230 djm 1445:
1446: closefrom(STDERR_FILENO + 1);
1.1 markus 1447:
1.127 markus 1448: if (!options.use_login)
1449: do_rc_files(s, shell);
1.67 markus 1450:
1451: /* restore SIGPIPE for child */
1.217 stevesk 1452: signal(SIGPIPE, SIG_DFL);
1.67 markus 1453:
1.248 djm 1454: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1455: printf("This service allows sftp connections only.\n");
1456: fflush(NULL);
1457: exit(1);
1458: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1459: extern int optind, optreset;
1460: int i;
1461: char *p, *args;
1462:
1.246 stevesk 1463: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1464: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1465: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1466: if (i < ARGV_MAX - 1)
1467: argv[i++] = p;
1468: argv[i] = NULL;
1469: optind = optreset = 1;
1470: __progname = argv[0];
1.226 djm 1471: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1472: }
1.247 djm 1473:
1474: fflush(NULL);
1.225 markus 1475:
1.127 markus 1476: if (options.use_login) {
1.130 provos 1477: launch_login(pw, hostname);
1478: /* NEVERREACHED */
1.127 markus 1479: }
1480:
1481: /* Get the last component of the shell name. */
1482: if ((shell0 = strrchr(shell, '/')) != NULL)
1483: shell0++;
1484: else
1485: shell0 = shell;
1486:
1.1 markus 1487: /*
1488: * If we have no command, execute the shell. In this case, the shell
1489: * name to be passed in argv[0] is preceded by '-' to indicate that
1490: * this is a login shell.
1491: */
1492: if (!command) {
1.127 markus 1493: char argv0[256];
1.1 markus 1494:
1.127 markus 1495: /* Start the shell. Set initial character to '-'. */
1496: argv0[0] = '-';
1.1 markus 1497:
1.127 markus 1498: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1499: >= sizeof(argv0) - 1) {
1.127 markus 1500: errno = EINVAL;
1.1 markus 1501: perror(shell);
1502: exit(1);
1.127 markus 1503: }
1.1 markus 1504:
1.127 markus 1505: /* Execute the shell. */
1506: argv[0] = argv0;
1507: argv[1] = NULL;
1508: execve(shell, argv, env);
1509:
1510: /* Executing the shell failed. */
1511: perror(shell);
1512: exit(1);
1.1 markus 1513: }
1514: /*
1515: * Execute the command using the user's shell. This uses the -c
1516: * option to execute the command.
1517: */
1.127 markus 1518: argv[0] = (char *) shell0;
1.1 markus 1519: argv[1] = "-c";
1520: argv[2] = (char *) command;
1521: argv[3] = NULL;
1522: execve(shell, argv, env);
1523: perror(shell);
1524: exit(1);
1525: }
1526:
1.237 djm 1527: void
1528: session_unused(int id)
1529: {
1530: debug3("%s: session id %d unused", __func__, id);
1531: if (id >= options.max_sessions ||
1532: id >= sessions_nalloc) {
1533: fatal("%s: insane session id %d (max %d nalloc %d)",
1534: __func__, id, options.max_sessions, sessions_nalloc);
1535: }
1.270 tedu 1536: memset(&sessions[id], 0, sizeof(*sessions));
1.237 djm 1537: sessions[id].self = id;
1538: sessions[id].used = 0;
1539: sessions[id].chanid = -1;
1540: sessions[id].ptyfd = -1;
1541: sessions[id].ttyfd = -1;
1542: sessions[id].ptymaster = -1;
1543: sessions[id].x11_chanids = NULL;
1544: sessions[id].next_unused = sessions_first_unused;
1545: sessions_first_unused = id;
1546: }
1547:
1.1 markus 1548: Session *
1549: session_new(void)
1550: {
1.237 djm 1551: Session *s, *tmp;
1552:
1553: if (sessions_first_unused == -1) {
1554: if (sessions_nalloc >= options.max_sessions)
1555: return NULL;
1556: debug2("%s: allocate (allocated %d max %d)",
1557: __func__, sessions_nalloc, options.max_sessions);
1558: tmp = xrealloc(sessions, sessions_nalloc + 1,
1559: sizeof(*sessions));
1560: if (tmp == NULL) {
1561: error("%s: cannot allocate %d sessions",
1562: __func__, sessions_nalloc + 1);
1563: return NULL;
1564: }
1565: sessions = tmp;
1566: session_unused(sessions_nalloc++);
1567: }
1568:
1569: if (sessions_first_unused >= sessions_nalloc ||
1570: sessions_first_unused < 0) {
1571: fatal("%s: insane first_unused %d max %d nalloc %d",
1572: __func__, sessions_first_unused, options.max_sessions,
1573: sessions_nalloc);
1574: }
1575:
1576: s = &sessions[sessions_first_unused];
1577: if (s->used) {
1578: fatal("%s: session %d already used",
1579: __func__, sessions_first_unused);
1580: }
1581: sessions_first_unused = s->next_unused;
1582: s->used = 1;
1583: s->next_unused = -1;
1584: debug("session_new: session %d", s->self);
1585:
1586: return s;
1.1 markus 1587: }
1588:
1.94 itojun 1589: static void
1.1 markus 1590: session_dump(void)
1591: {
1592: int i;
1.237 djm 1593: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1594: Session *s = &sessions[i];
1.237 djm 1595:
1596: debug("dump: used %d next_unused %d session %d %p "
1597: "channel %d pid %ld",
1.1 markus 1598: s->used,
1.237 djm 1599: s->next_unused,
1.1 markus 1600: s->self,
1601: s,
1602: s->chanid,
1.137 mpech 1603: (long)s->pid);
1.1 markus 1604: }
1605: }
1606:
1.2 markus 1607: int
1.97 markus 1608: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1609: {
1610: Session *s = session_new();
1611: debug("session_open: channel %d", chanid);
1612: if (s == NULL) {
1613: error("no more sessions");
1614: return 0;
1615: }
1.97 markus 1616: s->authctxt = authctxt;
1617: s->pw = authctxt->pw;
1.167 djm 1618: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1619: fatal("no user for session %d", s->self);
1.2 markus 1620: debug("session_open: session %d: link with channel %d", s->self, chanid);
1621: s->chanid = chanid;
1622: return 1;
1623: }
1624:
1.130 provos 1625: Session *
1626: session_by_tty(char *tty)
1627: {
1628: int i;
1.237 djm 1629: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1630: Session *s = &sessions[i];
1631: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1632: debug("session_by_tty: session %d tty %s", i, tty);
1633: return s;
1634: }
1635: }
1636: debug("session_by_tty: unknown tty %.100s", tty);
1637: session_dump();
1638: return NULL;
1639: }
1640:
1.94 itojun 1641: static Session *
1.2 markus 1642: session_by_channel(int id)
1643: {
1644: int i;
1.237 djm 1645: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1646: Session *s = &sessions[i];
1647: if (s->used && s->chanid == id) {
1.237 djm 1648: debug("session_by_channel: session %d channel %d",
1649: i, id);
1.2 markus 1650: return s;
1651: }
1652: }
1653: debug("session_by_channel: unknown channel %d", id);
1654: session_dump();
1655: return NULL;
1656: }
1657:
1.94 itojun 1658: static Session *
1.184 djm 1659: session_by_x11_channel(int id)
1660: {
1661: int i, j;
1662:
1.237 djm 1663: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1664: Session *s = &sessions[i];
1665:
1666: if (s->x11_chanids == NULL || !s->used)
1667: continue;
1668: for (j = 0; s->x11_chanids[j] != -1; j++) {
1669: if (s->x11_chanids[j] == id) {
1670: debug("session_by_x11_channel: session %d "
1671: "channel %d", s->self, id);
1672: return s;
1673: }
1674: }
1675: }
1676: debug("session_by_x11_channel: unknown channel %d", id);
1677: session_dump();
1678: return NULL;
1679: }
1680:
1681: static Session *
1.2 markus 1682: session_by_pid(pid_t pid)
1683: {
1684: int i;
1.137 mpech 1685: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1686: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1687: Session *s = &sessions[i];
1688: if (s->used && s->pid == pid)
1689: return s;
1690: }
1.137 mpech 1691: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1692: session_dump();
1693: return NULL;
1694: }
1695:
1.94 itojun 1696: static int
1.2 markus 1697: session_window_change_req(Session *s)
1698: {
1699: s->col = packet_get_int();
1700: s->row = packet_get_int();
1701: s->xpixel = packet_get_int();
1702: s->ypixel = packet_get_int();
1.116 markus 1703: packet_check_eom();
1.2 markus 1704: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1705: return 1;
1706: }
1707:
1.94 itojun 1708: static int
1.2 markus 1709: session_pty_req(Session *s)
1710: {
1.45 markus 1711: u_int len;
1.72 stevesk 1712: int n_bytes;
1.132 markus 1713:
1.268 djm 1714: if (no_pty_flag || !options.permit_tty) {
1.86 markus 1715: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1716: return 0;
1.86 markus 1717: }
1718: if (s->ttyfd != -1) {
1719: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1720: return 0;
1.86 markus 1721: }
1722:
1.2 markus 1723: s->term = packet_get_string(&len);
1.86 markus 1724:
1725: if (compat20) {
1726: s->col = packet_get_int();
1727: s->row = packet_get_int();
1728: } else {
1729: s->row = packet_get_int();
1730: s->col = packet_get_int();
1731: }
1.2 markus 1732: s->xpixel = packet_get_int();
1733: s->ypixel = packet_get_int();
1734:
1735: if (strcmp(s->term, "") == 0) {
1.265 djm 1736: free(s->term);
1.2 markus 1737: s->term = NULL;
1738: }
1.86 markus 1739:
1.2 markus 1740: /* Allocate a pty and open it. */
1.86 markus 1741: debug("Allocating pty.");
1.237 djm 1742: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1743: sizeof(s->tty)))) {
1.265 djm 1744: free(s->term);
1.2 markus 1745: s->term = NULL;
1746: s->ptyfd = -1;
1747: s->ttyfd = -1;
1748: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1749: return 0;
1.2 markus 1750: }
1751: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1752:
1753: /* for SSH1 the tty modes length is not given */
1754: if (!compat20)
1755: n_bytes = packet_remaining();
1756: tty_parse_modes(s->ttyfd, &n_bytes);
1757:
1.130 provos 1758: if (!use_privsep)
1759: pty_setowner(s->pw, s->tty);
1.86 markus 1760:
1761: /* Set window size from the packet. */
1.2 markus 1762: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1763:
1.116 markus 1764: packet_check_eom();
1.9 markus 1765: session_proctitle(s);
1.2 markus 1766: return 1;
1767: }
1768:
1.94 itojun 1769: static int
1.7 markus 1770: session_subsystem_req(Session *s)
1771: {
1.105 markus 1772: struct stat st;
1.45 markus 1773: u_int len;
1.7 markus 1774: int success = 0;
1.267 djm 1775: char *prog, *cmd;
1.182 djm 1776: u_int i;
1.7 markus 1777:
1.267 djm 1778: s->subsys = packet_get_string(&len);
1.116 markus 1779: packet_check_eom();
1.267 djm 1780: debug2("subsystem request for %.100s by user %s", s->subsys,
1.255 djm 1781: s->pw->pw_name);
1.18 jakob 1782:
1783: for (i = 0; i < options.num_subsystems; i++) {
1.267 djm 1784: if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1785: prog = options.subsystem_command[i];
1786: cmd = options.subsystem_args[i];
1.249 dtucker 1787: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1788: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1789: debug("subsystem: %s", prog);
1.225 markus 1790: } else {
1.249 dtucker 1791: if (stat(prog, &st) < 0)
1792: debug("subsystem: cannot stat %s: %s",
1793: prog, strerror(errno));
1.225 markus 1794: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1795: debug("subsystem: exec() %s", cmd);
1.105 markus 1796: }
1.237 djm 1797: success = do_exec(s, cmd) == 0;
1.122 markus 1798: break;
1.18 jakob 1799: }
1800: }
1801:
1802: if (!success)
1.267 djm 1803: logit("subsystem request for %.100s by user %s failed, "
1804: "subsystem not found", s->subsys, s->pw->pw_name);
1.7 markus 1805:
1806: return success;
1807: }
1808:
1.94 itojun 1809: static int
1.7 markus 1810: session_x11_req(Session *s)
1811: {
1.81 markus 1812: int success;
1.7 markus 1813:
1.184 djm 1814: if (s->auth_proto != NULL || s->auth_data != NULL) {
1815: error("session_x11_req: session %d: "
1.190 stevesk 1816: "x11 forwarding already active", s->self);
1.184 djm 1817: return 0;
1818: }
1.7 markus 1819: s->single_connection = packet_get_char();
1820: s->auth_proto = packet_get_string(NULL);
1821: s->auth_data = packet_get_string(NULL);
1822: s->screen = packet_get_int();
1.116 markus 1823: packet_check_eom();
1.7 markus 1824:
1.277.2.1! djm 1825: if (xauth_valid_string(s->auth_proto) &&
! 1826: xauth_valid_string(s->auth_data))
! 1827: success = session_setup_x11fwd(s);
! 1828: else {
! 1829: success = 0;
! 1830: error("Invalid X11 forwarding data");
! 1831: }
1.81 markus 1832: if (!success) {
1.265 djm 1833: free(s->auth_proto);
1834: free(s->auth_data);
1.84 markus 1835: s->auth_proto = NULL;
1836: s->auth_data = NULL;
1.7 markus 1837: }
1.81 markus 1838: return success;
1.7 markus 1839: }
1840:
1.94 itojun 1841: static int
1.19 markus 1842: session_shell_req(Session *s)
1843: {
1.116 markus 1844: packet_check_eom();
1.237 djm 1845: return do_exec(s, NULL) == 0;
1.19 markus 1846: }
1847:
1.94 itojun 1848: static int
1.19 markus 1849: session_exec_req(Session *s)
1850: {
1.237 djm 1851: u_int len, success;
1852:
1.19 markus 1853: char *command = packet_get_string(&len);
1.116 markus 1854: packet_check_eom();
1.237 djm 1855: success = do_exec(s, command) == 0;
1.265 djm 1856: free(command);
1.237 djm 1857: return success;
1.19 markus 1858: }
1859:
1.94 itojun 1860: static int
1.157 markus 1861: session_break_req(Session *s)
1862: {
1863:
1.175 deraadt 1864: packet_get_int(); /* ignored */
1.157 markus 1865: packet_check_eom();
1866:
1.259 djm 1867: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1868: return 0;
1869: return 1;
1870: }
1871:
1872: static int
1.173 djm 1873: session_env_req(Session *s)
1874: {
1875: char *name, *val;
1876: u_int name_len, val_len, i;
1877:
1.271 djm 1878: name = packet_get_cstring(&name_len);
1879: val = packet_get_cstring(&val_len);
1.173 djm 1880: packet_check_eom();
1881:
1882: /* Don't set too many environment variables */
1883: if (s->num_env > 128) {
1884: debug2("Ignoring env request %s: too many env vars", name);
1885: goto fail;
1886: }
1887:
1888: for (i = 0; i < options.num_accept_env; i++) {
1889: if (match_pattern(name, options.accept_env[i])) {
1890: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.201 djm 1891: s->env = xrealloc(s->env, s->num_env + 1,
1892: sizeof(*s->env));
1.173 djm 1893: s->env[s->num_env].name = name;
1894: s->env[s->num_env].val = val;
1895: s->num_env++;
1896: return (1);
1897: }
1898: }
1899: debug2("Ignoring env request %s: disallowed name", name);
1900:
1901: fail:
1.265 djm 1902: free(name);
1903: free(val);
1.173 djm 1904: return (0);
1905: }
1906:
1907: static int
1.43 markus 1908: session_auth_agent_req(Session *s)
1909: {
1910: static int called = 0;
1.116 markus 1911: packet_check_eom();
1.235 pyr 1912: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1913: debug("session_auth_agent_req: no_agent_forwarding_flag");
1914: return 0;
1915: }
1.43 markus 1916: if (called) {
1917: return 0;
1918: } else {
1919: called = 1;
1920: return auth_input_request_forwarding(s->pw);
1921: }
1922: }
1923:
1.123 markus 1924: int
1925: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1926: {
1927: int success = 0;
1928: Session *s;
1929:
1.123 markus 1930: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1931: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1932: c->self, rtype);
1933: return 0;
1934: }
1935: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1936:
1937: /*
1.64 markus 1938: * a session is in LARVAL state until a shell, a command
1939: * or a subsystem is executed
1.2 markus 1940: */
1941: if (c->type == SSH_CHANNEL_LARVAL) {
1942: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1943: success = session_shell_req(s);
1.2 markus 1944: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1945: success = session_exec_req(s);
1.2 markus 1946: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1947: success = session_pty_req(s);
1.7 markus 1948: } else if (strcmp(rtype, "x11-req") == 0) {
1949: success = session_x11_req(s);
1.43 markus 1950: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1951: success = session_auth_agent_req(s);
1.7 markus 1952: } else if (strcmp(rtype, "subsystem") == 0) {
1953: success = session_subsystem_req(s);
1.173 djm 1954: } else if (strcmp(rtype, "env") == 0) {
1955: success = session_env_req(s);
1.2 markus 1956: }
1957: }
1958: if (strcmp(rtype, "window-change") == 0) {
1959: success = session_window_change_req(s);
1.177 djm 1960: } else if (strcmp(rtype, "break") == 0) {
1961: success = session_break_req(s);
1.2 markus 1962: }
1.177 djm 1963:
1.123 markus 1964: return success;
1.2 markus 1965: }
1966:
1967: void
1.256 djm 1968: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1969: int is_tty)
1.2 markus 1970: {
1971: if (!compat20)
1972: fatal("session_set_fds: called for proto != 2.0");
1973: /*
1974: * now that have a child and a pipe to the child,
1975: * we can activate our channel and register the fd's
1976: */
1977: if (s->chanid == -1)
1978: fatal("no channel for session %d", s->self);
1979: channel_set_fds(s->chanid,
1980: fdout, fdin, fderr,
1.256 djm 1981: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1982: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1983: }
1984:
1.85 markus 1985: /*
1986: * Function to perform pty cleanup. Also called if we get aborted abnormally
1987: * (e.g., due to a dropped connection).
1988: */
1.130 provos 1989: void
1.165 markus 1990: session_pty_cleanup2(Session *s)
1.1 markus 1991: {
1.85 markus 1992: if (s == NULL) {
1993: error("session_pty_cleanup: no session");
1994: return;
1995: }
1996: if (s->ttyfd == -1)
1.1 markus 1997: return;
1998:
1.54 stevesk 1999: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 2000:
2001: /* Record that the user has logged out. */
1.85 markus 2002: if (s->pid != 0)
2003: record_logout(s->pid, s->tty);
1.1 markus 2004:
2005: /* Release the pseudo-tty. */
1.130 provos 2006: if (getuid() == 0)
2007: pty_release(s->tty);
1.1 markus 2008:
2009: /*
2010: * Close the server side of the socket pairs. We must do this after
2011: * the pty cleanup, so that another process doesn't get this pty
2012: * while we're still cleaning up.
2013: */
1.237 djm 2014: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2015: error("close(s->ptymaster/%d): %s",
2016: s->ptymaster, strerror(errno));
1.108 markus 2017:
2018: /* unlink pty from session */
2019: s->ttyfd = -1;
1.2 markus 2020: }
2021:
1.130 provos 2022: void
1.165 markus 2023: session_pty_cleanup(Session *s)
1.130 provos 2024: {
1.165 markus 2025: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 2026: }
2027:
1.147 markus 2028: static char *
2029: sig2name(int sig)
2030: {
2031: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2032: SSH_SIG(ABRT);
2033: SSH_SIG(ALRM);
2034: SSH_SIG(FPE);
2035: SSH_SIG(HUP);
2036: SSH_SIG(ILL);
2037: SSH_SIG(INT);
2038: SSH_SIG(KILL);
2039: SSH_SIG(PIPE);
2040: SSH_SIG(QUIT);
2041: SSH_SIG(SEGV);
2042: SSH_SIG(TERM);
2043: SSH_SIG(USR1);
2044: SSH_SIG(USR2);
2045: #undef SSH_SIG
2046: return "SIG@openssh.com";
2047: }
2048:
1.94 itojun 2049: static void
1.184 djm 2050: session_close_x11(int id)
2051: {
2052: Channel *c;
2053:
1.189 markus 2054: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2055: debug("session_close_x11: x11 channel %d missing", id);
2056: } else {
2057: /* Detach X11 listener */
2058: debug("session_close_x11: detach x11 channel %d", id);
2059: channel_cancel_cleanup(id);
2060: if (c->ostate != CHAN_OUTPUT_CLOSED)
2061: chan_mark_dead(c);
2062: }
2063: }
2064:
2065: static void
2066: session_close_single_x11(int id, void *arg)
2067: {
2068: Session *s;
2069: u_int i;
2070:
2071: debug3("session_close_single_x11: channel %d", id);
2072: channel_cancel_cleanup(id);
1.221 stevesk 2073: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2074: fatal("session_close_single_x11: no x11 channel %d", id);
2075: for (i = 0; s->x11_chanids[i] != -1; i++) {
2076: debug("session_close_single_x11: session %d: "
2077: "closing channel %d", s->self, s->x11_chanids[i]);
2078: /*
2079: * The channel "id" is already closing, but make sure we
2080: * close all of its siblings.
2081: */
2082: if (s->x11_chanids[i] != id)
2083: session_close_x11(s->x11_chanids[i]);
2084: }
1.265 djm 2085: free(s->x11_chanids);
1.184 djm 2086: s->x11_chanids = NULL;
1.265 djm 2087: free(s->display);
2088: s->display = NULL;
2089: free(s->auth_proto);
2090: s->auth_proto = NULL;
2091: free(s->auth_data);
2092: s->auth_data = NULL;
2093: free(s->auth_display);
2094: s->auth_display = NULL;
1.184 djm 2095: }
2096:
2097: static void
1.2 markus 2098: session_exit_message(Session *s, int status)
2099: {
2100: Channel *c;
1.124 markus 2101:
2102: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2103: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2104: s->self, s->chanid);
1.137 mpech 2105: debug("session_exit_message: session %d channel %d pid %ld",
2106: s->self, s->chanid, (long)s->pid);
1.2 markus 2107:
2108: if (WIFEXITED(status)) {
1.124 markus 2109: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2110: packet_put_int(WEXITSTATUS(status));
2111: packet_send();
2112: } else if (WIFSIGNALED(status)) {
1.124 markus 2113: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2114: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2115: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2116: packet_put_cstring("");
2117: packet_put_cstring("");
2118: packet_send();
2119: } else {
2120: /* Some weird exit cause. Just exit. */
2121: packet_disconnect("wait returned status %04x.", status);
2122: }
2123:
2124: /* disconnect channel */
2125: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2126:
2127: /*
2128: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2129: * the channel gets EOF. The session will be then be closed
1.187 djm 2130: * by session_close_by_channel when the childs close their fds.
2131: */
2132: channel_register_cleanup(c->self, session_close_by_channel, 1);
2133:
1.5 markus 2134: /*
2135: * emulate a write failure with 'chan_write_failed', nobody will be
2136: * interested in data we write.
2137: * Note that we must not call 'chan_read_failed', since there could
2138: * be some more data waiting in the pipe.
2139: */
1.8 markus 2140: if (c->ostate != CHAN_OUTPUT_CLOSED)
2141: chan_write_failed(c);
1.2 markus 2142: }
2143:
1.130 provos 2144: void
1.85 markus 2145: session_close(Session *s)
1.2 markus 2146: {
1.182 djm 2147: u_int i;
1.173 djm 2148:
1.137 mpech 2149: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165 markus 2150: if (s->ttyfd != -1)
1.85 markus 2151: session_pty_cleanup(s);
1.265 djm 2152: free(s->term);
2153: free(s->display);
2154: free(s->x11_chanids);
2155: free(s->auth_display);
2156: free(s->auth_data);
2157: free(s->auth_proto);
1.267 djm 2158: free(s->subsys);
1.219 djm 2159: if (s->env != NULL) {
2160: for (i = 0; i < s->num_env; i++) {
1.265 djm 2161: free(s->env[i].name);
2162: free(s->env[i].val);
1.219 djm 2163: }
1.265 djm 2164: free(s->env);
1.173 djm 2165: }
1.9 markus 2166: session_proctitle(s);
1.237 djm 2167: session_unused(s->self);
1.2 markus 2168: }
2169:
2170: void
2171: session_close_by_pid(pid_t pid, int status)
2172: {
2173: Session *s = session_by_pid(pid);
2174: if (s == NULL) {
1.137 mpech 2175: debug("session_close_by_pid: no session for pid %ld",
2176: (long)pid);
1.2 markus 2177: return;
2178: }
2179: if (s->chanid != -1)
2180: session_exit_message(s, status);
1.187 djm 2181: if (s->ttyfd != -1)
2182: session_pty_cleanup(s);
1.197 djm 2183: s->pid = 0;
1.98 markus 2184: }
2185:
1.2 markus 2186: /*
2187: * this is called when a channel dies before
2188: * the session 'child' itself dies
2189: */
2190: void
2191: session_close_by_channel(int id, void *arg)
2192: {
2193: Session *s = session_by_channel(id);
1.187 djm 2194: u_int i;
1.184 djm 2195:
1.2 markus 2196: if (s == NULL) {
1.107 markus 2197: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2198: return;
2199: }
1.137 mpech 2200: debug("session_close_by_channel: channel %d child %ld",
2201: id, (long)s->pid);
1.107 markus 2202: if (s->pid != 0) {
2203: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2204: /*
2205: * delay detach of session, but release pty, since
2206: * the fd's to the child are already closed
2207: */
1.165 markus 2208: if (s->ttyfd != -1)
1.108 markus 2209: session_pty_cleanup(s);
1.107 markus 2210: return;
2211: }
2212: /* detach by removing callback */
1.2 markus 2213: channel_cancel_cleanup(s->chanid);
1.187 djm 2214:
2215: /* Close any X11 listeners associated with this session */
2216: if (s->x11_chanids != NULL) {
2217: for (i = 0; s->x11_chanids[i] != -1; i++) {
2218: session_close_x11(s->x11_chanids[i]);
2219: s->x11_chanids[i] = -1;
2220: }
2221: }
2222:
1.2 markus 2223: s->chanid = -1;
1.106 markus 2224: session_close(s);
2225: }
2226:
2227: void
1.130 provos 2228: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2229: {
2230: int i;
1.237 djm 2231: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2232: Session *s = &sessions[i];
1.130 provos 2233: if (s->used) {
2234: if (closefunc != NULL)
2235: closefunc(s);
2236: else
2237: session_close(s);
2238: }
1.2 markus 2239: }
1.9 markus 2240: }
2241:
1.94 itojun 2242: static char *
1.9 markus 2243: session_tty_list(void)
2244: {
2245: static char buf[1024];
2246: int i;
2247: buf[0] = '\0';
1.237 djm 2248: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2249: Session *s = &sessions[i];
2250: if (s->used && s->ttyfd != -1) {
2251: if (buf[0] != '\0')
2252: strlcat(buf, ",", sizeof buf);
2253: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2254: }
2255: }
2256: if (buf[0] == '\0')
2257: strlcpy(buf, "notty", sizeof buf);
2258: return buf;
2259: }
2260:
2261: void
2262: session_proctitle(Session *s)
2263: {
2264: if (s->pw == NULL)
2265: error("no user for session %d", s->self);
2266: else
2267: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2268: }
2269:
2270: int
2271: session_setup_x11fwd(Session *s)
2272: {
2273: struct stat st;
1.109 stevesk 2274: char display[512], auth_display[512];
1.272 djm 2275: char hostname[NI_MAXHOST];
1.184 djm 2276: u_int i;
1.81 markus 2277:
2278: if (no_x11_forwarding_flag) {
2279: packet_send_debug("X11 forwarding disabled in user configuration file.");
2280: return 0;
2281: }
2282: if (!options.x11_forwarding) {
2283: debug("X11 forwarding disabled in server configuration file.");
2284: return 0;
2285: }
1.275 djm 2286: if (options.xauth_location == NULL ||
1.81 markus 2287: (stat(options.xauth_location, &st) == -1)) {
2288: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2289: return 0;
2290: }
2291: if (options.use_login) {
2292: packet_send_debug("X11 forwarding disabled; "
2293: "not compatible with UseLogin=yes.");
1.81 markus 2294: return 0;
2295: }
1.87 markus 2296: if (s->display != NULL) {
1.81 markus 2297: debug("X11 display already set.");
2298: return 0;
2299: }
1.140 deraadt 2300: if (x11_create_display_inet(options.x11_display_offset,
2301: options.x11_use_localhost, s->single_connection,
1.184 djm 2302: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2303: debug("x11_create_display_inet failed.");
1.81 markus 2304: return 0;
1.184 djm 2305: }
2306: for (i = 0; s->x11_chanids[i] != -1; i++) {
2307: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2308: session_close_single_x11, 0);
1.81 markus 2309: }
1.109 stevesk 2310:
2311: /* Set up a suitable value for the DISPLAY variable. */
2312: if (gethostname(hostname, sizeof(hostname)) < 0)
2313: fatal("gethostname: %.100s", strerror(errno));
2314: /*
2315: * auth_display must be used as the displayname when the
2316: * authorization entry is added with xauth(1). This will be
2317: * different than the DISPLAY string for localhost displays.
2318: */
1.119 stevesk 2319: if (options.x11_use_localhost) {
1.140 deraadt 2320: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2321: s->display_number, s->screen);
1.140 deraadt 2322: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2323: s->display_number, s->screen);
1.109 stevesk 2324: s->display = xstrdup(display);
1.118 stevesk 2325: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2326: } else {
1.140 deraadt 2327: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2328: s->display_number, s->screen);
2329: s->display = xstrdup(display);
1.118 stevesk 2330: s->auth_display = xstrdup(display);
1.109 stevesk 2331: }
2332:
1.81 markus 2333: return 1;
1.2 markus 2334: }
2335:
1.94 itojun 2336: static void
1.49 markus 2337: do_authenticated2(Authctxt *authctxt)
1.2 markus 2338: {
1.97 markus 2339: server_loop2(authctxt);
1.165 markus 2340: }
2341:
2342: void
2343: do_cleanup(Authctxt *authctxt)
2344: {
2345: static int called = 0;
2346:
2347: debug("do_cleanup");
2348:
2349: /* no cleanup if we're in the child for login shell */
2350: if (is_child)
2351: return;
2352:
2353: /* avoid double cleanup */
2354: if (called)
2355: return;
2356: called = 1;
2357:
1.218 markus 2358: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2359: return;
2360: #ifdef KRB5
2361: if (options.kerberos_ticket_cleanup &&
2362: authctxt->krb5_ctx)
2363: krb5_cleanup_proc(authctxt);
1.161 markus 2364: #endif
1.165 markus 2365:
2366: #ifdef GSSAPI
2367: if (compat20 && options.gss_cleanup_creds)
2368: ssh_gssapi_cleanup_creds();
2369: #endif
2370:
2371: /* remove agent socket */
2372: auth_sock_cleanup_proc(authctxt->pw);
2373:
2374: /*
2375: * Cleanup ptys/utmp only if privsep is disabled,
2376: * or if running in monitor.
2377: */
2378: if (!use_privsep || mm_is_monitor())
2379: session_destroy_all(session_pty_cleanup2);
1.1 markus 2380: }
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