Annotation of src/usr.bin/ssh/session.c, Revision 1.277
1.277 ! deraadt 1: /* $OpenBSD: session.c,v 1.276 2015/01/14 20:05:27 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:
1.209 stevesk 43: #include <errno.h>
1.253 djm 44: #include <fcntl.h>
1.204 stevesk 45: #include <grp.h>
1.223 djm 46: #include <login_cap.h>
1.272 djm 47: #include <netdb.h>
1.192 stevesk 48: #include <paths.h>
1.206 stevesk 49: #include <pwd.h>
1.195 stevesk 50: #include <signal.h>
1.215 stevesk 51: #include <stdio.h>
1.214 stevesk 52: #include <stdlib.h>
1.212 stevesk 53: #include <string.h>
1.211 stevesk 54: #include <unistd.h>
1.277 ! deraadt 55: #include <limits.h>
1.1 markus 56:
1.216 deraadt 57: #include "xmalloc.h"
1.51 markus 58: #include "ssh.h"
59: #include "ssh1.h"
60: #include "ssh2.h"
1.59 djm 61: #include "sshpty.h"
1.1 markus 62: #include "packet.h"
63: #include "buffer.h"
1.173 djm 64: #include "match.h"
1.1 markus 65: #include "uidswap.h"
66: #include "compat.h"
1.78 markus 67: #include "channels.h"
1.216 deraadt 68: #include "key.h"
69: #include "cipher.h"
70: #include "kex.h"
71: #include "hostfile.h"
1.2 markus 72: #include "auth.h"
1.19 markus 73: #include "auth-options.h"
1.266 markus 74: #include "authfd.h"
1.50 markus 75: #include "pathnames.h"
1.51 markus 76: #include "log.h"
1.274 millert 77: #include "misc.h"
1.51 markus 78: #include "servconf.h"
1.59 djm 79: #include "sshlogin.h"
1.51 markus 80: #include "serverloop.h"
81: #include "canohost.h"
1.55 itojun 82: #include "session.h"
1.216 deraadt 83: #ifdef GSSAPI
84: #include "ssh-gss.h"
85: #endif
1.130 provos 86: #include "monitor_wrap.h"
1.225 markus 87: #include "sftp.h"
1.171 markus 88:
89: #ifdef KRB5
90: #include <kafs.h>
1.161 markus 91: #endif
92:
1.242 djm 93: #define IS_INTERNAL_SFTP(c) \
94: (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
95: (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
96: c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
97: c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
98:
1.1 markus 99: /* func */
100:
101: Session *session_new(void);
1.256 djm 102: void session_set_fds(Session *, int, int, int, int, int);
1.165 markus 103: void session_pty_cleanup(Session *);
1.94 itojun 104: void session_proctitle(Session *);
105: int session_setup_x11fwd(Session *);
1.237 djm 106: int do_exec_pty(Session *, const char *);
107: int do_exec_no_pty(Session *, const char *);
108: int do_exec(Session *, const char *);
1.94 itojun 109: void do_login(Session *, const char *);
110: void do_child(Session *, const char *);
1.73 djm 111: void do_motd(void);
1.94 itojun 112: int check_quietlogin(Session *, const char *);
1.1 markus 113:
1.94 itojun 114: static void do_authenticated1(Authctxt *);
115: static void do_authenticated2(Authctxt *);
116:
117: static int session_pty_req(Session *);
1.65 markus 118:
1.1 markus 119: /* import */
120: extern ServerOptions options;
121: extern char *__progname;
122: extern int log_stderr;
123: extern int debug_flag;
1.45 markus 124: extern u_int utmp_len;
1.21 markus 125: extern int startup_pipe;
1.74 markus 126: extern void destroy_sensitive_data(void);
1.179 dtucker 127: extern Buffer loginmsg;
1.21 markus 128:
1.34 markus 129: /* original command from peer. */
1.92 markus 130: const char *original_command = NULL;
1.34 markus 131:
1.1 markus 132: /* data */
1.237 djm 133: static int sessions_first_unused = -1;
134: static int sessions_nalloc = 0;
135: static Session *sessions = NULL;
1.1 markus 136:
1.248 djm 137: #define SUBSYSTEM_NONE 0
138: #define SUBSYSTEM_EXT 1
139: #define SUBSYSTEM_INT_SFTP 2
140: #define SUBSYSTEM_INT_SFTP_ERROR 3
1.225 markus 141:
1.129 provos 142: login_cap_t *lc;
1.28 millert 143:
1.165 markus 144: static int is_child = 0;
145:
1.136 markus 146: /* Name and directory of socket for authentication agent forwarding. */
147: static char *auth_sock_name = NULL;
148: static char *auth_sock_dir = NULL;
149:
150: /* removes the agent forwarding socket */
151:
152: static void
1.165 markus 153: auth_sock_cleanup_proc(struct passwd *pw)
1.136 markus 154: {
155: if (auth_sock_name != NULL) {
156: temporarily_use_uid(pw);
157: unlink(auth_sock_name);
158: rmdir(auth_sock_dir);
159: auth_sock_name = NULL;
160: restore_uid();
161: }
162: }
163:
164: static int
165: auth_input_request_forwarding(struct passwd * pw)
166: {
167: Channel *nc;
1.237 djm 168: int sock = -1;
1.136 markus 169:
170: if (auth_sock_name != NULL) {
171: error("authentication forwarding requested twice.");
172: return 0;
173: }
174:
175: /* Temporarily drop privileged uid for mkdir/bind. */
176: temporarily_use_uid(pw);
177:
178: /* Allocate a buffer for the socket name, and format the name. */
1.237 djm 179: auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
1.136 markus 180:
181: /* Create private directory for socket */
182: if (mkdtemp(auth_sock_dir) == NULL) {
183: packet_send_debug("Agent forwarding disabled: "
184: "mkdtemp() failed: %.100s", strerror(errno));
185: restore_uid();
1.265 djm 186: free(auth_sock_dir);
1.136 markus 187: auth_sock_dir = NULL;
1.237 djm 188: goto authsock_err;
1.136 markus 189: }
1.237 djm 190:
191: xasprintf(&auth_sock_name, "%s/agent.%ld",
192: auth_sock_dir, (long) getpid());
1.136 markus 193:
1.274 millert 194: /* Start a Unix listener on auth_sock_name. */
195: sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0);
1.136 markus 196:
197: /* Restore the privileged uid. */
198: restore_uid();
199:
1.274 millert 200: /* Check for socket/bind/listen failure. */
201: if (sock < 0)
1.237 djm 202: goto authsock_err;
1.136 markus 203:
204: /* Allocate a channel for the authentication agent socket. */
205: nc = channel_new("auth socket",
206: SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
207: CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1.156 markus 208: 0, "auth socket", 1);
1.245 djm 209: nc->path = xstrdup(auth_sock_name);
1.136 markus 210: return 1;
1.237 djm 211:
212: authsock_err:
1.265 djm 213: free(auth_sock_name);
1.237 djm 214: if (auth_sock_dir != NULL) {
215: rmdir(auth_sock_dir);
1.265 djm 216: free(auth_sock_dir);
1.237 djm 217: }
218: if (sock != -1)
219: close(sock);
220: auth_sock_name = NULL;
221: auth_sock_dir = NULL;
222: return 0;
1.136 markus 223: }
224:
1.179 dtucker 225: static void
226: display_loginmsg(void)
227: {
1.183 djm 228: if (buffer_len(&loginmsg) > 0) {
229: buffer_append(&loginmsg, "\0", 1);
230: printf("%s", (char *)buffer_ptr(&loginmsg));
231: buffer_clear(&loginmsg);
232: }
1.179 dtucker 233: }
1.136 markus 234:
1.65 markus 235: void
236: do_authenticated(Authctxt *authctxt)
237: {
1.153 markus 238: setproctitle("%s", authctxt->pw->pw_name);
239:
1.65 markus 240: /* setup the channel layer */
1.274 millert 241: /* XXX - streamlocal? */
1.261 djm 242: if (no_port_forwarding_flag ||
243: (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
244: channel_disable_adm_local_opens();
245: else
1.65 markus 246: channel_permit_all_opens();
1.252 dtucker 247:
248: auth_debug_send();
1.65 markus 249:
250: if (compat20)
251: do_authenticated2(authctxt);
252: else
253: do_authenticated1(authctxt);
1.79 markus 254:
1.165 markus 255: do_cleanup(authctxt);
1.65 markus 256: }
257:
1.1 markus 258: /*
259: * Prepares for an interactive session. This is called after the user has
260: * been successfully authenticated. During this message exchange, pseudo
261: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
262: * are requested, etc.
263: */
1.94 itojun 264: static void
1.65 markus 265: do_authenticated1(Authctxt *authctxt)
1.1 markus 266: {
267: Session *s;
1.65 markus 268: char *command;
1.117 markus 269: int success, type, screen_flag;
1.139 deraadt 270: int enable_compression_after_reply = 0;
271: u_int proto_len, data_len, dlen, compression_level = 0;
1.1 markus 272:
1.61 markus 273: s = session_new();
1.181 markus 274: if (s == NULL) {
275: error("no more sessions");
276: return;
277: }
1.96 dugsong 278: s->authctxt = authctxt;
1.65 markus 279: s->pw = authctxt->pw;
1.28 millert 280:
1.1 markus 281: /*
282: * We stay in this loop until the client requests to execute a shell
283: * or a command.
284: */
285: for (;;) {
1.65 markus 286: success = 0;
1.1 markus 287:
288: /* Get a packet from the client. */
1.117 markus 289: type = packet_read();
1.1 markus 290:
291: /* Process the packet. */
292: switch (type) {
293: case SSH_CMSG_REQUEST_COMPRESSION:
294: compression_level = packet_get_int();
1.116 markus 295: packet_check_eom();
1.1 markus 296: if (compression_level < 1 || compression_level > 9) {
1.180 markus 297: packet_send_debug("Received invalid compression level %d.",
1.112 deraadt 298: compression_level);
1.138 markus 299: break;
300: }
1.186 markus 301: if (options.compression == COMP_NONE) {
1.138 markus 302: debug2("compression disabled");
1.1 markus 303: break;
304: }
305: /* Enable compression after we have responded with SUCCESS. */
306: enable_compression_after_reply = 1;
307: success = 1;
308: break;
309:
310: case SSH_CMSG_REQUEST_PTY:
1.86 markus 311: success = session_pty_req(s);
1.1 markus 312: break;
313:
314: case SSH_CMSG_X11_REQUEST_FORWARDING:
315: s->auth_proto = packet_get_string(&proto_len);
316: s->auth_data = packet_get_string(&data_len);
317:
1.57 markus 318: screen_flag = packet_get_protocol_flags() &
319: SSH_PROTOFLAG_SCREEN_NUMBER;
320: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
321:
322: if (packet_remaining() == 4) {
323: if (!screen_flag)
324: debug2("Buggy client: "
325: "X11 screen flag missing");
1.1 markus 326: s->screen = packet_get_int();
1.56 markus 327: } else {
1.1 markus 328: s->screen = 0;
1.56 markus 329: }
1.116 markus 330: packet_check_eom();
1.81 markus 331: success = session_setup_x11fwd(s);
332: if (!success) {
1.265 djm 333: free(s->auth_proto);
334: free(s->auth_data);
1.84 markus 335: s->auth_proto = NULL;
336: s->auth_data = NULL;
1.1 markus 337: }
338: break;
339:
340: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1.235 pyr 341: if (!options.allow_agent_forwarding ||
342: no_agent_forwarding_flag || compat13) {
1.1 markus 343: debug("Authentication agent forwarding not permitted for this authentication.");
344: break;
345: }
346: debug("Received authentication agent forwarding request.");
1.65 markus 347: success = auth_input_request_forwarding(s->pw);
1.1 markus 348: break;
349:
350: case SSH_CMSG_PORT_FORWARD_REQUEST:
351: if (no_port_forwarding_flag) {
352: debug("Port forwarding not permitted for this authentication.");
1.39 markus 353: break;
354: }
1.261 djm 355: if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
1.39 markus 356: debug("Port forwarding not permitted.");
1.1 markus 357: break;
358: }
359: debug("Received TCP/IP port forwarding request.");
1.208 markus 360: if (channel_input_port_forward_request(s->pw->pw_uid == 0,
1.274 millert 361: &options.fwd_opts) < 0) {
1.208 markus 362: debug("Port forwarding failed.");
363: break;
364: }
1.1 markus 365: success = 1;
366: break;
367:
368: case SSH_CMSG_MAX_PACKET_SIZE:
369: if (packet_set_maxsize(packet_get_int()) > 0)
370: success = 1;
371: break;
372:
373: case SSH_CMSG_EXEC_SHELL:
374: case SSH_CMSG_EXEC_CMD:
375: if (type == SSH_CMSG_EXEC_CMD) {
376: command = packet_get_string(&dlen);
377: debug("Exec command '%.500s'", command);
1.237 djm 378: if (do_exec(s, command) != 0)
379: packet_disconnect(
380: "command execution failed");
1.265 djm 381: free(command);
1.1 markus 382: } else {
1.237 djm 383: if (do_exec(s, NULL) != 0)
384: packet_disconnect(
385: "shell execution failed");
1.1 markus 386: }
1.116 markus 387: packet_check_eom();
1.82 markus 388: session_close(s);
1.1 markus 389: return;
390:
391: default:
392: /*
393: * Any unknown messages in this phase are ignored,
394: * and a failure message is returned.
395: */
1.155 itojun 396: logit("Unknown packet type received after authentication: %d", type);
1.1 markus 397: }
398: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
399: packet_send();
400: packet_write_wait();
401:
402: /* Enable compression now that we have replied if appropriate. */
403: if (enable_compression_after_reply) {
404: enable_compression_after_reply = 0;
405: packet_start_compression(compression_level);
406: }
407: }
408: }
409:
1.269 dtucker 410: #define USE_PIPES 1
1.1 markus 411: /*
412: * This is called to fork and execute a command when we have no tty. This
413: * will call do_child from the child, and server_loop from the parent after
414: * setting up file descriptors and such.
415: */
1.237 djm 416: int
1.63 markus 417: do_exec_no_pty(Session *s, const char *command)
1.1 markus 418: {
1.137 mpech 419: pid_t pid;
1.238 markus 420: #ifdef USE_PIPES
421: int pin[2], pout[2], perr[2];
422:
1.253 djm 423: if (s == NULL)
424: fatal("do_exec_no_pty: no session");
425:
1.238 markus 426: /* Allocate pipes for communicating with the program. */
427: if (pipe(pin) < 0) {
428: error("%s: pipe in: %.100s", __func__, strerror(errno));
429: return -1;
430: }
431: if (pipe(pout) < 0) {
432: error("%s: pipe out: %.100s", __func__, strerror(errno));
433: close(pin[0]);
434: close(pin[1]);
435: return -1;
436: }
1.256 djm 437: if (pipe(perr) < 0) {
438: error("%s: pipe err: %.100s", __func__,
439: strerror(errno));
440: close(pin[0]);
441: close(pin[1]);
442: close(pout[0]);
443: close(pout[1]);
444: return -1;
1.238 markus 445: }
446: #else
1.237 djm 447: int inout[2], err[2];
1.1 markus 448:
1.253 djm 449: if (s == NULL)
450: fatal("do_exec_no_pty: no session");
451:
1.1 markus 452: /* Uses socket pairs to communicate with the program. */
1.237 djm 453: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
454: error("%s: socketpair #1: %.100s", __func__, strerror(errno));
455: return -1;
456: }
1.256 djm 457: if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
458: error("%s: socketpair #2: %.100s", __func__,
459: strerror(errno));
460: close(inout[0]);
461: close(inout[1]);
462: return -1;
1.237 djm 463: }
1.238 markus 464: #endif
1.237 djm 465:
1.9 markus 466: session_proctitle(s);
1.1 markus 467:
468: /* Fork the child. */
1.237 djm 469: switch ((pid = fork())) {
470: case -1:
471: error("%s: fork: %.100s", __func__, strerror(errno));
1.238 markus 472: #ifdef USE_PIPES
473: close(pin[0]);
474: close(pin[1]);
475: close(pout[0]);
476: close(pout[1]);
1.256 djm 477: close(perr[0]);
1.238 markus 478: close(perr[1]);
479: #else
1.237 djm 480: close(inout[0]);
481: close(inout[1]);
482: close(err[0]);
1.256 djm 483: close(err[1]);
1.238 markus 484: #endif
1.237 djm 485: return -1;
486: case 0:
1.165 markus 487: is_child = 1;
1.144 markus 488:
1.1 markus 489: /* Child. Reinitialize the log since the pid has changed. */
1.237 djm 490: log_init(__progname, options.log_level,
491: options.log_facility, log_stderr);
1.1 markus 492:
493: /*
494: * Create a new session and process group since the 4.4BSD
495: * setlogin() affects the entire process group.
496: */
497: if (setsid() < 0)
498: error("setsid failed: %.100s", strerror(errno));
499:
1.238 markus 500: #ifdef USE_PIPES
501: /*
502: * Redirect stdin. We close the parent side of the socket
503: * pair, and make the child side the standard input.
504: */
505: close(pin[1]);
506: if (dup2(pin[0], 0) < 0)
507: perror("dup2 stdin");
508: close(pin[0]);
509:
510: /* Redirect stdout. */
511: close(pout[0]);
512: if (dup2(pout[1], 1) < 0)
513: perror("dup2 stdout");
514: close(pout[1]);
515:
516: /* Redirect stderr. */
1.256 djm 517: close(perr[0]);
1.238 markus 518: if (dup2(perr[1], 2) < 0)
519: perror("dup2 stderr");
520: close(perr[1]);
521: #else
1.1 markus 522: /*
523: * Redirect stdin, stdout, and stderr. Stdin and stdout will
524: * use the same socket, as some programs (particularly rdist)
525: * seem to depend on it.
526: */
527: close(inout[1]);
1.256 djm 528: close(err[1]);
1.1 markus 529: if (dup2(inout[0], 0) < 0) /* stdin */
530: perror("dup2 stdin");
1.237 djm 531: if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
1.1 markus 532: perror("dup2 stdout");
1.238 markus 533: close(inout[0]);
1.1 markus 534: if (dup2(err[0], 2) < 0) /* stderr */
535: perror("dup2 stderr");
1.238 markus 536: close(err[0]);
537: #endif
1.1 markus 538:
539: /* Do processing for the child (exec command etc). */
1.60 markus 540: do_child(s, command);
1.1 markus 541: /* NOTREACHED */
1.237 djm 542: default:
543: break;
1.1 markus 544: }
1.237 djm 545:
1.1 markus 546: s->pid = pid;
1.47 markus 547: /* Set interactive/non-interactive mode. */
1.257 djm 548: packet_set_interactive(s->display != NULL,
549: options.ip_qos_interactive, options.ip_qos_bulk);
1.1 markus 550:
1.238 markus 551: #ifdef USE_PIPES
552: /* We are the parent. Close the child sides of the pipes. */
553: close(pin[0]);
554: close(pout[1]);
555: close(perr[1]);
556:
557: if (compat20) {
1.256 djm 558: session_set_fds(s, pin[1], pout[0], perr[0],
559: s->is_subsystem, 0);
1.238 markus 560: } else {
561: /* Enter the interactive session. */
562: server_loop(pid, pin[1], pout[0], perr[0]);
563: /* server_loop has closed pin[1], pout[0], and perr[0]. */
564: }
565: #else
1.1 markus 566: /* We are the parent. Close the child sides of the socket pairs. */
567: close(inout[0]);
568: close(err[0]);
569:
570: /*
571: * Enter the interactive session. Note: server_loop must be able to
572: * handle the case that fdin and fdout are the same.
573: */
1.2 markus 574: if (compat20) {
1.256 djm 575: session_set_fds(s, inout[1], inout[1], err[1],
576: s->is_subsystem, 0);
1.2 markus 577: } else {
578: server_loop(pid, inout[1], inout[1], err[1]);
579: /* server_loop has closed inout[1] and err[1]. */
580: }
1.238 markus 581: #endif
1.237 djm 582: return 0;
1.1 markus 583: }
584:
585: /*
586: * This is called to fork and execute a command when we have a tty. This
587: * will call do_child from the child, and server_loop from the parent after
588: * setting up file descriptors, controlling tty, updating wtmp, utmp,
589: * lastlog, and other such operations.
590: */
1.237 djm 591: int
1.63 markus 592: do_exec_pty(Session *s, const char *command)
1.1 markus 593: {
594: int fdout, ptyfd, ttyfd, ptymaster;
595: pid_t pid;
596:
597: if (s == NULL)
598: fatal("do_exec_pty: no session");
599: ptyfd = s->ptyfd;
600: ttyfd = s->ttyfd;
601:
1.237 djm 602: /*
603: * Create another descriptor of the pty master side for use as the
604: * standard input. We could use the original descriptor, but this
605: * simplifies code in server_loop. The descriptor is bidirectional.
606: * Do this before forking (and cleanup in the child) so as to
607: * detect and gracefully fail out-of-fd conditions.
608: */
609: if ((fdout = dup(ptyfd)) < 0) {
610: error("%s: dup #1: %s", __func__, strerror(errno));
611: close(ttyfd);
612: close(ptyfd);
613: return -1;
614: }
615: /* we keep a reference to the pty master */
616: if ((ptymaster = dup(ptyfd)) < 0) {
617: error("%s: dup #2: %s", __func__, strerror(errno));
618: close(ttyfd);
619: close(ptyfd);
620: close(fdout);
621: return -1;
622: }
623:
1.1 markus 624: /* Fork the child. */
1.237 djm 625: switch ((pid = fork())) {
626: case -1:
627: error("%s: fork: %.100s", __func__, strerror(errno));
628: close(fdout);
629: close(ptymaster);
630: close(ttyfd);
631: close(ptyfd);
632: return -1;
633: case 0:
1.165 markus 634: is_child = 1;
1.97 markus 635:
1.237 djm 636: close(fdout);
637: close(ptymaster);
638:
1.24 markus 639: /* Child. Reinitialize the log because the pid has changed. */
1.237 djm 640: log_init(__progname, options.log_level,
641: options.log_facility, log_stderr);
1.1 markus 642: /* Close the master side of the pseudo tty. */
643: close(ptyfd);
644:
645: /* Make the pseudo tty our controlling tty. */
646: pty_make_controlling_tty(&ttyfd, s->tty);
647:
1.103 markus 648: /* Redirect stdin/stdout/stderr from the pseudo tty. */
649: if (dup2(ttyfd, 0) < 0)
650: error("dup2 stdin: %s", strerror(errno));
651: if (dup2(ttyfd, 1) < 0)
652: error("dup2 stdout: %s", strerror(errno));
653: if (dup2(ttyfd, 2) < 0)
654: error("dup2 stderr: %s", strerror(errno));
1.1 markus 655:
656: /* Close the extra descriptor for the pseudo tty. */
657: close(ttyfd);
658:
1.24 markus 659: /* record login, etc. similar to login(1) */
1.41 markus 660: if (!(options.use_login && command == NULL))
661: do_login(s, command);
1.228 djm 662:
1.237 djm 663: /*
664: * Do common processing for the child, such as execing
665: * the command.
666: */
1.60 markus 667: do_child(s, command);
1.1 markus 668: /* NOTREACHED */
1.237 djm 669: default:
670: break;
1.1 markus 671: }
672: s->pid = pid;
673:
674: /* Parent. Close the slave side of the pseudo tty. */
675: close(ttyfd);
676:
1.237 djm 677: /* Enter interactive session. */
1.1 markus 678: s->ptymaster = ptymaster;
1.257 djm 679: packet_set_interactive(1,
680: options.ip_qos_interactive, options.ip_qos_bulk);
1.2 markus 681: if (compat20) {
1.256 djm 682: session_set_fds(s, ptyfd, fdout, -1, 1, 1);
1.2 markus 683: } else {
684: server_loop(pid, ptyfd, fdout, -1);
685: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 686: }
1.237 djm 687: return 0;
1.24 markus 688: }
689:
1.90 markus 690: /*
691: * This is called to fork and execute a command. If another command is
692: * to be forced, execute that instead.
693: */
1.237 djm 694: int
1.90 markus 695: do_exec(Session *s, const char *command)
696: {
1.237 djm 697: int ret;
1.267 djm 698: const char *forced = NULL;
699: char session_type[1024], *tty = NULL;
1.237 djm 700:
1.210 dtucker 701: if (options.adm_forced_command) {
702: original_command = command;
703: command = options.adm_forced_command;
1.267 djm 704: forced = "(config)";
1.210 dtucker 705: } else if (forced_command) {
1.90 markus 706: original_command = command;
707: command = forced_command;
1.267 djm 708: forced = "(key-option)";
709: }
710: if (forced != NULL) {
1.248 djm 711: if (IS_INTERNAL_SFTP(command)) {
712: s->is_subsystem = s->is_subsystem ?
713: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
714: } else if (s->is_subsystem)
1.225 markus 715: s->is_subsystem = SUBSYSTEM_EXT;
1.267 djm 716: snprintf(session_type, sizeof(session_type),
717: "forced-command %s '%.900s'", forced, command);
718: } else if (s->is_subsystem) {
719: snprintf(session_type, sizeof(session_type),
720: "subsystem '%.900s'", s->subsys);
721: } else if (command == NULL) {
722: snprintf(session_type, sizeof(session_type), "shell");
723: } else {
724: /* NB. we don't log unforced commands to preserve privacy */
725: snprintf(session_type, sizeof(session_type), "command");
1.90 markus 726: }
1.163 markus 727:
1.267 djm 728: if (s->ttyfd != -1) {
729: tty = s->tty;
730: if (strncmp(tty, "/dev/", 5) == 0)
731: tty += 5;
732: }
733:
734: verbose("Starting session: %s%s%s for %s from %.200s port %d",
735: session_type,
736: tty == NULL ? "" : " on ",
737: tty == NULL ? "" : tty,
738: s->pw->pw_name,
739: get_remote_ipaddr(),
740: get_remote_port());
741:
1.163 markus 742: #ifdef GSSAPI
743: if (options.gss_authentication) {
744: temporarily_use_uid(s->pw);
745: ssh_gssapi_storecreds();
746: restore_uid();
747: }
748: #endif
1.90 markus 749: if (s->ttyfd != -1)
1.237 djm 750: ret = do_exec_pty(s, command);
1.90 markus 751: else
1.237 djm 752: ret = do_exec_no_pty(s, command);
1.90 markus 753:
1.92 markus 754: original_command = NULL;
1.179 dtucker 755:
756: /*
757: * Clear loginmsg: it's the child's responsibility to display
758: * it to the user, otherwise multiple sessions may accumulate
759: * multiple copies of the login messages.
760: */
761: buffer_clear(&loginmsg);
1.237 djm 762:
763: return ret;
1.90 markus 764: }
765:
766:
1.24 markus 767: /* administrative, login(1)-like work */
768: void
1.41 markus 769: do_login(Session *s, const char *command)
1.24 markus 770: {
771: socklen_t fromlen;
772: struct sockaddr_storage from;
773: struct passwd * pw = s->pw;
774: pid_t pid = getpid();
775:
776: /*
777: * Get IP address of client. If the connection is not a socket, let
778: * the address be 0.0.0.0.
779: */
780: memset(&from, 0, sizeof(from));
1.148 stevesk 781: fromlen = sizeof(from);
1.24 markus 782: if (packet_connection_is_on_socket()) {
783: if (getpeername(packet_get_connection_in(),
1.200 deraadt 784: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 785: debug("getpeername: %.100s", strerror(errno));
1.165 markus 786: cleanup_exit(255);
1.24 markus 787: }
788: }
1.25 markus 789:
1.24 markus 790: /* Record that there was a login on that tty from the remote host. */
1.133 markus 791: if (!use_privsep)
792: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
793: get_remote_name_or_ip(utmp_len,
1.158 markus 794: options.use_dns),
1.148 stevesk 795: (struct sockaddr *)&from, fromlen);
1.24 markus 796:
1.73 djm 797: if (check_quietlogin(s, command))
1.24 markus 798: return;
1.73 djm 799:
1.179 dtucker 800: display_loginmsg();
1.73 djm 801:
802: do_motd();
803: }
804:
805: /*
806: * Display the message of the day.
807: */
808: void
809: do_motd(void)
810: {
811: FILE *f;
812: char buf[256];
813:
1.24 markus 814: if (options.print_motd) {
1.28 millert 815: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
816: "/etc/motd"), "r");
1.24 markus 817: if (f) {
818: while (fgets(buf, sizeof(buf), f))
819: fputs(buf, stdout);
820: fclose(f);
821: }
1.2 markus 822: }
1.73 djm 823: }
824:
825:
826: /*
827: * Check for quiet login, either .hushlogin or command given.
828: */
829: int
830: check_quietlogin(Session *s, const char *command)
831: {
832: char buf[256];
1.96 dugsong 833: struct passwd *pw = s->pw;
1.73 djm 834: struct stat st;
835:
836: /* Return 1 if .hushlogin exists or a command given. */
837: if (command != NULL)
838: return 1;
839: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
840: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
841: return 1;
842: return 0;
1.1 markus 843: }
844:
845: /*
846: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 847: * already exists, its value is overridden.
1.1 markus 848: */
1.161 markus 849: void
1.45 markus 850: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 851: const char *value)
1.1 markus 852: {
1.164 markus 853: char **env;
854: u_int envsize;
1.45 markus 855: u_int i, namelen;
1.1 markus 856:
1.271 djm 857: if (strchr(name, '=') != NULL) {
858: error("Invalid environment variable \"%.100s\"", name);
859: return;
860: }
861:
1.1 markus 862: /*
863: * Find the slot where the value should be stored. If the variable
864: * already exists, we reuse the slot; otherwise we append a new slot
865: * at the end of the array, expanding if necessary.
866: */
867: env = *envp;
868: namelen = strlen(name);
869: for (i = 0; env[i]; i++)
870: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
871: break;
872: if (env[i]) {
873: /* Reuse the slot. */
1.265 djm 874: free(env[i]);
1.1 markus 875: } else {
876: /* New variable. Expand if necessary. */
1.164 markus 877: envsize = *envsizep;
878: if (i >= envsize - 1) {
879: if (envsize >= 1000)
880: fatal("child_set_env: too many env vars");
881: envsize += 50;
1.201 djm 882: env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1.164 markus 883: *envsizep = envsize;
1.1 markus 884: }
885: /* Need to set the NULL pointer at end of array beyond the new slot. */
886: env[i + 1] = NULL;
887: }
888:
889: /* Allocate space and format the variable in the appropriate slot. */
890: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
891: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
892: }
893:
894: /*
895: * Reads environment variables from the given file and adds/overrides them
896: * into the environment. If the file does not exist, this does nothing.
897: * Otherwise, it must consist of empty lines, comments (line starts with '#')
898: * and assignments of the form name=value. No other forms are allowed.
899: */
1.94 itojun 900: static void
1.45 markus 901: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 902: const char *filename)
1.1 markus 903: {
904: FILE *f;
905: char buf[4096];
906: char *cp, *value;
1.142 deraadt 907: u_int lineno = 0;
1.1 markus 908:
909: f = fopen(filename, "r");
910: if (!f)
911: return;
912:
913: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 914: if (++lineno > 1000)
915: fatal("Too many lines in environment file %s", filename);
1.1 markus 916: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
917: ;
918: if (!*cp || *cp == '#' || *cp == '\n')
919: continue;
1.224 gilles 920:
921: cp[strcspn(cp, "\n")] = '\0';
922:
1.1 markus 923: value = strchr(cp, '=');
924: if (value == NULL) {
1.142 deraadt 925: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
926: filename);
1.1 markus 927: continue;
928: }
1.14 deraadt 929: /*
930: * Replace the equals sign by nul, and advance value to
931: * the value string.
932: */
1.1 markus 933: *value = '\0';
934: value++;
935: child_set_env(env, envsize, cp, value);
936: }
937: fclose(f);
938: }
939:
1.127 markus 940: static char **
941: do_setup_env(Session *s, const char *shell)
1.1 markus 942: {
943: char buf[256];
1.127 markus 944: u_int i, envsize;
1.154 markus 945: char **env, *laddr;
1.127 markus 946: struct passwd *pw = s->pw;
1.1 markus 947:
948: /* Initialize the environment. */
949: envsize = 100;
1.220 djm 950: env = xcalloc(envsize, sizeof(char *));
1.1 markus 951: env[0] = NULL;
952:
1.161 markus 953: #ifdef GSSAPI
1.168 djm 954: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 955: * the childs environment as they see fit
956: */
957: ssh_gssapi_do_child(&env, &envsize);
958: #endif
959:
1.1 markus 960: if (!options.use_login) {
961: /* Set basic environment. */
1.173 djm 962: for (i = 0; i < s->num_env; i++)
1.178 deraadt 963: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 964: s->env[i].val);
965:
1.1 markus 966: child_set_env(&env, &envsize, "USER", pw->pw_name);
967: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
968: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 969: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
970: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
971: else
972: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 973:
974: snprintf(buf, sizeof buf, "%.200s/%.50s",
975: _PATH_MAILDIR, pw->pw_name);
976: child_set_env(&env, &envsize, "MAIL", buf);
977:
978: /* Normal systems set SHELL by default. */
979: child_set_env(&env, &envsize, "SHELL", shell);
980: }
981: if (getenv("TZ"))
982: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
983:
984: /* Set custom environment options from RSA authentication. */
1.110 markus 985: if (!options.use_login) {
986: while (custom_environment) {
987: struct envstring *ce = custom_environment;
1.143 deraadt 988: char *str = ce->s;
1.127 markus 989:
1.143 deraadt 990: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 991: ;
1.143 deraadt 992: if (str[i] == '=') {
993: str[i] = 0;
994: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 995: }
996: custom_environment = ce->next;
1.265 djm 997: free(ce->s);
998: free(ce);
1.1 markus 999: }
1000: }
1001:
1.149 stevesk 1002: /* SSH_CLIENT deprecated */
1.1 markus 1003: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 1004: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 1005: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1006:
1.154 markus 1007: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1008: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 1009: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1.265 djm 1010: free(laddr);
1.149 stevesk 1011: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1012:
1.60 markus 1013: if (s->ttyfd != -1)
1014: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1015: if (s->term)
1016: child_set_env(&env, &envsize, "TERM", s->term);
1017: if (s->display)
1018: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1019: if (original_command)
1020: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1021: original_command);
1.96 dugsong 1022: #ifdef KRB5
1023: if (s->authctxt->krb5_ticket_file)
1024: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1025: s->authctxt->krb5_ticket_file);
1.96 dugsong 1026: #endif
1.136 markus 1027: if (auth_sock_name != NULL)
1.1 markus 1028: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1029: auth_sock_name);
1.1 markus 1030:
1031: /* read $HOME/.ssh/environment. */
1.146 markus 1032: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1033: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1034: pw->pw_dir);
1.1 markus 1035: read_environment_file(&env, &envsize, buf);
1036: }
1037: if (debug_flag) {
1038: /* dump the environment */
1039: fprintf(stderr, "Environment:\n");
1040: for (i = 0; env[i]; i++)
1041: fprintf(stderr, " %.200s\n", env[i]);
1042: }
1.127 markus 1043: return env;
1044: }
1045:
1046: /*
1047: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1048: * first in this order).
1049: */
1050: static void
1051: do_rc_files(Session *s, const char *shell)
1052: {
1053: FILE *f = NULL;
1054: char cmd[1024];
1055: int do_xauth;
1056: struct stat st;
1057:
1058: do_xauth =
1059: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1060:
1.231 djm 1061: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1062: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.273 djm 1063: !no_user_rc && options.permit_user_rc &&
1064: stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1065: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1066: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1067: if (debug_flag)
1068: fprintf(stderr, "Running %s\n", cmd);
1069: f = popen(cmd, "w");
1070: if (f) {
1071: if (do_xauth)
1072: fprintf(f, "%s %s\n", s->auth_proto,
1073: s->auth_data);
1074: pclose(f);
1075: } else
1076: fprintf(stderr, "Could not run %s\n",
1077: _PATH_SSH_USER_RC);
1078: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1079: if (debug_flag)
1080: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1081: _PATH_SSH_SYSTEM_RC);
1082: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1083: if (f) {
1084: if (do_xauth)
1085: fprintf(f, "%s %s\n", s->auth_proto,
1086: s->auth_data);
1087: pclose(f);
1088: } else
1089: fprintf(stderr, "Could not run %s\n",
1090: _PATH_SSH_SYSTEM_RC);
1091: } else if (do_xauth && options.xauth_location != NULL) {
1092: /* Add authority data to .Xauthority if appropriate. */
1093: if (debug_flag) {
1094: fprintf(stderr,
1.151 stevesk 1095: "Running %.500s remove %.100s\n",
1.165 markus 1096: options.xauth_location, s->auth_display);
1.151 stevesk 1097: fprintf(stderr,
1098: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1099: options.xauth_location, s->auth_display,
1100: s->auth_proto, s->auth_data);
1101: }
1102: snprintf(cmd, sizeof cmd, "%s -q -",
1103: options.xauth_location);
1104: f = popen(cmd, "w");
1105: if (f) {
1.151 stevesk 1106: fprintf(f, "remove %s\n",
1107: s->auth_display);
1.127 markus 1108: fprintf(f, "add %s %s %s\n",
1109: s->auth_display, s->auth_proto,
1110: s->auth_data);
1111: pclose(f);
1112: } else {
1113: fprintf(stderr, "Could not run %s\n",
1114: cmd);
1115: }
1116: }
1117: }
1118:
1119: static void
1120: do_nologin(struct passwd *pw)
1121: {
1122: FILE *f = NULL;
1.251 dtucker 1123: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1124: struct stat sb;
1.127 markus 1125:
1.260 guenther 1126: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1127: return;
1128: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1129:
1130: if (stat(nl, &sb) == -1) {
1131: if (nl != def_nl)
1.265 djm 1132: free(nl);
1.251 dtucker 1133: return;
1134: }
1135:
1136: /* /etc/nologin exists. Print its contents if we can and exit. */
1137: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1138: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1139: while (fgets(buf, sizeof(buf), f))
1140: fputs(buf, stderr);
1141: fclose(f);
1142: }
1.251 dtucker 1143: exit(254);
1.127 markus 1144: }
1145:
1.226 djm 1146: /*
1147: * Chroot into a directory after checking it for safety: all path components
1148: * must be root-owned directories with strict permissions.
1149: */
1150: static void
1151: safely_chroot(const char *path, uid_t uid)
1152: {
1153: const char *cp;
1.277 ! deraadt 1154: char component[PATH_MAX];
1.226 djm 1155: struct stat st;
1156:
1157: if (*path != '/')
1158: fatal("chroot path does not begin at root");
1159: if (strlen(path) >= sizeof(component))
1160: fatal("chroot path too long");
1161:
1162: /*
1163: * Descend the path, checking that each component is a
1164: * root-owned directory with strict permissions.
1165: */
1166: for (cp = path; cp != NULL;) {
1167: if ((cp = strchr(cp, '/')) == NULL)
1168: strlcpy(component, path, sizeof(component));
1169: else {
1170: cp++;
1171: memcpy(component, path, cp - path);
1172: component[cp - path] = '\0';
1173: }
1174:
1175: debug3("%s: checking '%s'", __func__, component);
1176:
1177: if (stat(component, &st) != 0)
1178: fatal("%s: stat(\"%s\"): %s", __func__,
1179: component, strerror(errno));
1180: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1181: fatal("bad ownership or modes for chroot "
1182: "directory %s\"%s\"",
1183: cp == NULL ? "" : "component ", component);
1184: if (!S_ISDIR(st.st_mode))
1185: fatal("chroot path %s\"%s\" is not a directory",
1186: cp == NULL ? "" : "component ", component);
1187:
1188: }
1189:
1190: if (chdir(path) == -1)
1191: fatal("Unable to chdir to chroot path \"%s\": "
1192: "%s", path, strerror(errno));
1193: if (chroot(path) == -1)
1194: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1195: if (chdir("/") == -1)
1196: fatal("%s: chdir(/) after chroot: %s",
1197: __func__, strerror(errno));
1198: verbose("Changed root directory to \"%s\"", path);
1199: }
1200:
1.127 markus 1201: /* Set login name, uid, gid, and groups. */
1.130 provos 1202: void
1.127 markus 1203: do_setusercontext(struct passwd *pw)
1204: {
1.227 djm 1205: char *chroot_path, *tmp;
1206:
1.127 markus 1207: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1208: /* Prepare groups */
1.127 markus 1209: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1210: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1211: perror("unable to set user context");
1212: exit(1);
1213: }
1.226 djm 1214:
1215: if (options.chroot_directory != NULL &&
1216: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1217: tmp = tilde_expand_filename(options.chroot_directory,
1218: pw->pw_uid);
1219: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1220: "u", pw->pw_name, (char *)NULL);
1.226 djm 1221: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1222: free(tmp);
1.226 djm 1223: free(chroot_path);
1.264 djm 1224: /* Make sure we don't attempt to chroot again */
1225: free(options.chroot_directory);
1226: options.chroot_directory = NULL;
1.226 djm 1227: }
1228:
1229: /* Set UID */
1230: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1231: perror("unable to set user context (setuser)");
1232: exit(1);
1233: }
1.264 djm 1234: } else if (options.chroot_directory != NULL &&
1235: strcasecmp(options.chroot_directory, "none") != 0) {
1236: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1237: }
1.264 djm 1238:
1.127 markus 1239: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1240: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1241: }
1242:
1.131 markus 1243: static void
1.172 markus 1244: do_pwchange(Session *s)
1245: {
1.179 dtucker 1246: fflush(NULL);
1.172 markus 1247: fprintf(stderr, "WARNING: Your password has expired.\n");
1248: if (s->ttyfd != -1) {
1.178 deraadt 1249: fprintf(stderr,
1.172 markus 1250: "You must change your password now and login again!\n");
1251: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1252: perror("passwd");
1253: } else {
1254: fprintf(stderr,
1255: "Password change required but no TTY available.\n");
1256: }
1257: exit(1);
1258: }
1259:
1260: static void
1.130 provos 1261: launch_login(struct passwd *pw, const char *hostname)
1262: {
1263: /* Launch login(1). */
1264:
1265: execl("/usr/bin/login", "login", "-h", hostname,
1266: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1267:
1268: /* Login couldn't be executed, die. */
1269:
1270: perror("login");
1271: exit(1);
1272: }
1273:
1.172 markus 1274: static void
1275: child_close_fds(void)
1276: {
1.276 djm 1277: extern int auth_sock;
1.266 markus 1278:
1.276 djm 1279: if (auth_sock != -1) {
1280: close(auth_sock);
1281: auth_sock = -1;
1.266 markus 1282: }
1283:
1.172 markus 1284: if (packet_get_connection_in() == packet_get_connection_out())
1285: close(packet_get_connection_in());
1286: else {
1287: close(packet_get_connection_in());
1288: close(packet_get_connection_out());
1289: }
1290: /*
1291: * Close all descriptors related to channels. They will still remain
1292: * open in the parent.
1293: */
1294: /* XXX better use close-on-exec? -markus */
1295: channel_close_all();
1296:
1297: /*
1298: * Close any extra file descriptors. Note that there may still be
1299: * descriptors left by system functions. They will be closed later.
1300: */
1301: endpwent();
1302:
1303: /*
1.188 djm 1304: * Close any extra open file descriptors so that we don't have them
1.172 markus 1305: * hanging around in clients. Note that we want to do this after
1306: * initgroups, because at least on Solaris 2.3 it leaves file
1307: * descriptors open.
1308: */
1.258 djm 1309: closefrom(STDERR_FILENO + 1);
1.172 markus 1310: }
1311:
1.127 markus 1312: /*
1313: * Performs common processing for the child, such as setting up the
1314: * environment, closing extra file descriptors, setting the user and group
1315: * ids, and executing the command or shell.
1316: */
1.225 markus 1317: #define ARGV_MAX 10
1.127 markus 1318: void
1319: do_child(Session *s, const char *command)
1320: {
1321: extern char **environ;
1322: char **env;
1.225 markus 1323: char *argv[ARGV_MAX];
1.127 markus 1324: const char *shell, *shell0, *hostname = NULL;
1325: struct passwd *pw = s->pw;
1.239 djm 1326: int r = 0;
1.127 markus 1327:
1328: /* remove hostkey from the child's memory */
1329: destroy_sensitive_data();
1330:
1.172 markus 1331: /* Force a password change */
1332: if (s->authctxt->force_pwchange) {
1333: do_setusercontext(pw);
1334: child_close_fds();
1335: do_pwchange(s);
1336: exit(1);
1337: }
1338:
1.127 markus 1339: /* login(1) is only called if we execute the login shell */
1340: if (options.use_login && command != NULL)
1341: options.use_login = 0;
1342:
1343: /*
1344: * Login(1) does this as well, and it needs uid 0 for the "-h"
1345: * switch, so we let login(1) to this for us.
1346: */
1347: if (!options.use_login) {
1348: do_nologin(pw);
1349: do_setusercontext(pw);
1350: }
1351:
1352: /*
1353: * Get the shell from the password data. An empty shell field is
1354: * legal, and means /bin/sh.
1355: */
1356: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1357:
1358: /*
1359: * Make sure $SHELL points to the shell from the password file,
1360: * even if shell is overridden from login.conf
1361: */
1362: env = do_setup_env(s, shell);
1363:
1.127 markus 1364: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1365:
1.26 millert 1366: /* we have to stash the hostname before we close our socket. */
1367: if (options.use_login)
1.70 stevesk 1368: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1369: options.use_dns);
1.1 markus 1370: /*
1371: * Close the connection descriptors; note that this is the child, and
1372: * the server will still have the socket open, and it is important
1373: * that we do not shutdown it. Note that the descriptors cannot be
1374: * closed before building the environment, as we call
1375: * get_remote_ipaddr there.
1376: */
1.172 markus 1377: child_close_fds();
1.1 markus 1378:
1379: /*
1.125 deraadt 1380: * Must take new environment into use so that .ssh/rc,
1381: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1382: */
1383: environ = env;
1.170 jakob 1384:
1385: #ifdef KRB5
1386: /*
1387: * At this point, we check to see if AFS is active and if we have
1388: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1389: * if we can (and need to) extend the ticket into an AFS token. If
1390: * we don't do this, we run into potential problems if the user's
1391: * home directory is in AFS and it's not world-readable.
1392: */
1393:
1394: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1395: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1396: char cell[64];
1397:
1398: debug("Getting AFS token");
1399:
1400: k_setpag();
1401:
1402: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1403: krb5_afslog(s->authctxt->krb5_ctx,
1404: s->authctxt->krb5_fwd_ccache, cell, NULL);
1405:
1406: krb5_afslog_home(s->authctxt->krb5_ctx,
1407: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1408: }
1409: #endif
1.104 markus 1410:
1.188 djm 1411: /* Change current directory to the user's home directory. */
1.104 markus 1412: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1413: /* Suppress missing homedir warning for chroot case */
1414: r = login_getcapbool(lc, "requirehome", 0);
1.254 djm 1415: if (r || options.chroot_directory == NULL ||
1416: strcasecmp(options.chroot_directory, "none") == 0)
1.239 djm 1417: fprintf(stderr, "Could not chdir to home "
1418: "directory %s: %s\n", pw->pw_dir,
1419: strerror(errno));
1420: if (r)
1.104 markus 1421: exit(1);
1422: }
1.230 djm 1423:
1424: closefrom(STDERR_FILENO + 1);
1.1 markus 1425:
1.127 markus 1426: if (!options.use_login)
1427: do_rc_files(s, shell);
1.67 markus 1428:
1429: /* restore SIGPIPE for child */
1.217 stevesk 1430: signal(SIGPIPE, SIG_DFL);
1.67 markus 1431:
1.248 djm 1432: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1433: printf("This service allows sftp connections only.\n");
1434: fflush(NULL);
1435: exit(1);
1436: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1437: extern int optind, optreset;
1438: int i;
1439: char *p, *args;
1440:
1.246 stevesk 1441: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1442: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1443: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1444: if (i < ARGV_MAX - 1)
1445: argv[i++] = p;
1446: argv[i] = NULL;
1447: optind = optreset = 1;
1448: __progname = argv[0];
1.226 djm 1449: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1450: }
1.247 djm 1451:
1452: fflush(NULL);
1.225 markus 1453:
1.127 markus 1454: if (options.use_login) {
1.130 provos 1455: launch_login(pw, hostname);
1456: /* NEVERREACHED */
1.127 markus 1457: }
1458:
1459: /* Get the last component of the shell name. */
1460: if ((shell0 = strrchr(shell, '/')) != NULL)
1461: shell0++;
1462: else
1463: shell0 = shell;
1464:
1.1 markus 1465: /*
1466: * If we have no command, execute the shell. In this case, the shell
1467: * name to be passed in argv[0] is preceded by '-' to indicate that
1468: * this is a login shell.
1469: */
1470: if (!command) {
1.127 markus 1471: char argv0[256];
1.1 markus 1472:
1.127 markus 1473: /* Start the shell. Set initial character to '-'. */
1474: argv0[0] = '-';
1.1 markus 1475:
1.127 markus 1476: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1477: >= sizeof(argv0) - 1) {
1.127 markus 1478: errno = EINVAL;
1.1 markus 1479: perror(shell);
1480: exit(1);
1.127 markus 1481: }
1.1 markus 1482:
1.127 markus 1483: /* Execute the shell. */
1484: argv[0] = argv0;
1485: argv[1] = NULL;
1486: execve(shell, argv, env);
1487:
1488: /* Executing the shell failed. */
1489: perror(shell);
1490: exit(1);
1.1 markus 1491: }
1492: /*
1493: * Execute the command using the user's shell. This uses the -c
1494: * option to execute the command.
1495: */
1.127 markus 1496: argv[0] = (char *) shell0;
1.1 markus 1497: argv[1] = "-c";
1498: argv[2] = (char *) command;
1499: argv[3] = NULL;
1500: execve(shell, argv, env);
1501: perror(shell);
1502: exit(1);
1503: }
1504:
1.237 djm 1505: void
1506: session_unused(int id)
1507: {
1508: debug3("%s: session id %d unused", __func__, id);
1509: if (id >= options.max_sessions ||
1510: id >= sessions_nalloc) {
1511: fatal("%s: insane session id %d (max %d nalloc %d)",
1512: __func__, id, options.max_sessions, sessions_nalloc);
1513: }
1.270 tedu 1514: memset(&sessions[id], 0, sizeof(*sessions));
1.237 djm 1515: sessions[id].self = id;
1516: sessions[id].used = 0;
1517: sessions[id].chanid = -1;
1518: sessions[id].ptyfd = -1;
1519: sessions[id].ttyfd = -1;
1520: sessions[id].ptymaster = -1;
1521: sessions[id].x11_chanids = NULL;
1522: sessions[id].next_unused = sessions_first_unused;
1523: sessions_first_unused = id;
1524: }
1525:
1.1 markus 1526: Session *
1527: session_new(void)
1528: {
1.237 djm 1529: Session *s, *tmp;
1530:
1531: if (sessions_first_unused == -1) {
1532: if (sessions_nalloc >= options.max_sessions)
1533: return NULL;
1534: debug2("%s: allocate (allocated %d max %d)",
1535: __func__, sessions_nalloc, options.max_sessions);
1536: tmp = xrealloc(sessions, sessions_nalloc + 1,
1537: sizeof(*sessions));
1538: if (tmp == NULL) {
1539: error("%s: cannot allocate %d sessions",
1540: __func__, sessions_nalloc + 1);
1541: return NULL;
1542: }
1543: sessions = tmp;
1544: session_unused(sessions_nalloc++);
1545: }
1546:
1547: if (sessions_first_unused >= sessions_nalloc ||
1548: sessions_first_unused < 0) {
1549: fatal("%s: insane first_unused %d max %d nalloc %d",
1550: __func__, sessions_first_unused, options.max_sessions,
1551: sessions_nalloc);
1552: }
1553:
1554: s = &sessions[sessions_first_unused];
1555: if (s->used) {
1556: fatal("%s: session %d already used",
1557: __func__, sessions_first_unused);
1558: }
1559: sessions_first_unused = s->next_unused;
1560: s->used = 1;
1561: s->next_unused = -1;
1562: debug("session_new: session %d", s->self);
1563:
1564: return s;
1.1 markus 1565: }
1566:
1.94 itojun 1567: static void
1.1 markus 1568: session_dump(void)
1569: {
1570: int i;
1.237 djm 1571: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1572: Session *s = &sessions[i];
1.237 djm 1573:
1574: debug("dump: used %d next_unused %d session %d %p "
1575: "channel %d pid %ld",
1.1 markus 1576: s->used,
1.237 djm 1577: s->next_unused,
1.1 markus 1578: s->self,
1579: s,
1580: s->chanid,
1.137 mpech 1581: (long)s->pid);
1.1 markus 1582: }
1583: }
1584:
1.2 markus 1585: int
1.97 markus 1586: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1587: {
1588: Session *s = session_new();
1589: debug("session_open: channel %d", chanid);
1590: if (s == NULL) {
1591: error("no more sessions");
1592: return 0;
1593: }
1.97 markus 1594: s->authctxt = authctxt;
1595: s->pw = authctxt->pw;
1.167 djm 1596: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1597: fatal("no user for session %d", s->self);
1.2 markus 1598: debug("session_open: session %d: link with channel %d", s->self, chanid);
1599: s->chanid = chanid;
1600: return 1;
1601: }
1602:
1.130 provos 1603: Session *
1604: session_by_tty(char *tty)
1605: {
1606: int i;
1.237 djm 1607: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1608: Session *s = &sessions[i];
1609: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1610: debug("session_by_tty: session %d tty %s", i, tty);
1611: return s;
1612: }
1613: }
1614: debug("session_by_tty: unknown tty %.100s", tty);
1615: session_dump();
1616: return NULL;
1617: }
1618:
1.94 itojun 1619: static Session *
1.2 markus 1620: session_by_channel(int id)
1621: {
1622: int i;
1.237 djm 1623: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1624: Session *s = &sessions[i];
1625: if (s->used && s->chanid == id) {
1.237 djm 1626: debug("session_by_channel: session %d channel %d",
1627: i, id);
1.2 markus 1628: return s;
1629: }
1630: }
1631: debug("session_by_channel: unknown channel %d", id);
1632: session_dump();
1633: return NULL;
1634: }
1635:
1.94 itojun 1636: static Session *
1.184 djm 1637: session_by_x11_channel(int id)
1638: {
1639: int i, j;
1640:
1.237 djm 1641: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1642: Session *s = &sessions[i];
1643:
1644: if (s->x11_chanids == NULL || !s->used)
1645: continue;
1646: for (j = 0; s->x11_chanids[j] != -1; j++) {
1647: if (s->x11_chanids[j] == id) {
1648: debug("session_by_x11_channel: session %d "
1649: "channel %d", s->self, id);
1650: return s;
1651: }
1652: }
1653: }
1654: debug("session_by_x11_channel: unknown channel %d", id);
1655: session_dump();
1656: return NULL;
1657: }
1658:
1659: static Session *
1.2 markus 1660: session_by_pid(pid_t pid)
1661: {
1662: int i;
1.137 mpech 1663: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1664: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1665: Session *s = &sessions[i];
1666: if (s->used && s->pid == pid)
1667: return s;
1668: }
1.137 mpech 1669: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1670: session_dump();
1671: return NULL;
1672: }
1673:
1.94 itojun 1674: static int
1.2 markus 1675: session_window_change_req(Session *s)
1676: {
1677: s->col = packet_get_int();
1678: s->row = packet_get_int();
1679: s->xpixel = packet_get_int();
1680: s->ypixel = packet_get_int();
1.116 markus 1681: packet_check_eom();
1.2 markus 1682: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1683: return 1;
1684: }
1685:
1.94 itojun 1686: static int
1.2 markus 1687: session_pty_req(Session *s)
1688: {
1.45 markus 1689: u_int len;
1.72 stevesk 1690: int n_bytes;
1.132 markus 1691:
1.268 djm 1692: if (no_pty_flag || !options.permit_tty) {
1.86 markus 1693: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1694: return 0;
1.86 markus 1695: }
1696: if (s->ttyfd != -1) {
1697: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1698: return 0;
1.86 markus 1699: }
1700:
1.2 markus 1701: s->term = packet_get_string(&len);
1.86 markus 1702:
1703: if (compat20) {
1704: s->col = packet_get_int();
1705: s->row = packet_get_int();
1706: } else {
1707: s->row = packet_get_int();
1708: s->col = packet_get_int();
1709: }
1.2 markus 1710: s->xpixel = packet_get_int();
1711: s->ypixel = packet_get_int();
1712:
1713: if (strcmp(s->term, "") == 0) {
1.265 djm 1714: free(s->term);
1.2 markus 1715: s->term = NULL;
1716: }
1.86 markus 1717:
1.2 markus 1718: /* Allocate a pty and open it. */
1.86 markus 1719: debug("Allocating pty.");
1.237 djm 1720: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1721: sizeof(s->tty)))) {
1.265 djm 1722: free(s->term);
1.2 markus 1723: s->term = NULL;
1724: s->ptyfd = -1;
1725: s->ttyfd = -1;
1726: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1727: return 0;
1.2 markus 1728: }
1729: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1730:
1731: /* for SSH1 the tty modes length is not given */
1732: if (!compat20)
1733: n_bytes = packet_remaining();
1734: tty_parse_modes(s->ttyfd, &n_bytes);
1735:
1.130 provos 1736: if (!use_privsep)
1737: pty_setowner(s->pw, s->tty);
1.86 markus 1738:
1739: /* Set window size from the packet. */
1.2 markus 1740: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1741:
1.116 markus 1742: packet_check_eom();
1.9 markus 1743: session_proctitle(s);
1.2 markus 1744: return 1;
1745: }
1746:
1.94 itojun 1747: static int
1.7 markus 1748: session_subsystem_req(Session *s)
1749: {
1.105 markus 1750: struct stat st;
1.45 markus 1751: u_int len;
1.7 markus 1752: int success = 0;
1.267 djm 1753: char *prog, *cmd;
1.182 djm 1754: u_int i;
1.7 markus 1755:
1.267 djm 1756: s->subsys = packet_get_string(&len);
1.116 markus 1757: packet_check_eom();
1.267 djm 1758: debug2("subsystem request for %.100s by user %s", s->subsys,
1.255 djm 1759: s->pw->pw_name);
1.18 jakob 1760:
1761: for (i = 0; i < options.num_subsystems; i++) {
1.267 djm 1762: if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1763: prog = options.subsystem_command[i];
1764: cmd = options.subsystem_args[i];
1.249 dtucker 1765: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1766: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1767: debug("subsystem: %s", prog);
1.225 markus 1768: } else {
1.249 dtucker 1769: if (stat(prog, &st) < 0)
1770: debug("subsystem: cannot stat %s: %s",
1771: prog, strerror(errno));
1.225 markus 1772: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1773: debug("subsystem: exec() %s", cmd);
1.105 markus 1774: }
1.237 djm 1775: success = do_exec(s, cmd) == 0;
1.122 markus 1776: break;
1.18 jakob 1777: }
1778: }
1779:
1780: if (!success)
1.267 djm 1781: logit("subsystem request for %.100s by user %s failed, "
1782: "subsystem not found", s->subsys, s->pw->pw_name);
1.7 markus 1783:
1784: return success;
1785: }
1786:
1.94 itojun 1787: static int
1.7 markus 1788: session_x11_req(Session *s)
1789: {
1.81 markus 1790: int success;
1.7 markus 1791:
1.184 djm 1792: if (s->auth_proto != NULL || s->auth_data != NULL) {
1793: error("session_x11_req: session %d: "
1.190 stevesk 1794: "x11 forwarding already active", s->self);
1.184 djm 1795: return 0;
1796: }
1.7 markus 1797: s->single_connection = packet_get_char();
1798: s->auth_proto = packet_get_string(NULL);
1799: s->auth_data = packet_get_string(NULL);
1800: s->screen = packet_get_int();
1.116 markus 1801: packet_check_eom();
1.7 markus 1802:
1.81 markus 1803: success = session_setup_x11fwd(s);
1804: if (!success) {
1.265 djm 1805: free(s->auth_proto);
1806: free(s->auth_data);
1.84 markus 1807: s->auth_proto = NULL;
1808: s->auth_data = NULL;
1.7 markus 1809: }
1.81 markus 1810: return success;
1.7 markus 1811: }
1812:
1.94 itojun 1813: static int
1.19 markus 1814: session_shell_req(Session *s)
1815: {
1.116 markus 1816: packet_check_eom();
1.237 djm 1817: return do_exec(s, NULL) == 0;
1.19 markus 1818: }
1819:
1.94 itojun 1820: static int
1.19 markus 1821: session_exec_req(Session *s)
1822: {
1.237 djm 1823: u_int len, success;
1824:
1.19 markus 1825: char *command = packet_get_string(&len);
1.116 markus 1826: packet_check_eom();
1.237 djm 1827: success = do_exec(s, command) == 0;
1.265 djm 1828: free(command);
1.237 djm 1829: return success;
1.19 markus 1830: }
1831:
1.94 itojun 1832: static int
1.157 markus 1833: session_break_req(Session *s)
1834: {
1835:
1.175 deraadt 1836: packet_get_int(); /* ignored */
1.157 markus 1837: packet_check_eom();
1838:
1.259 djm 1839: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1840: return 0;
1841: return 1;
1842: }
1843:
1844: static int
1.173 djm 1845: session_env_req(Session *s)
1846: {
1847: char *name, *val;
1848: u_int name_len, val_len, i;
1849:
1.271 djm 1850: name = packet_get_cstring(&name_len);
1851: val = packet_get_cstring(&val_len);
1.173 djm 1852: packet_check_eom();
1853:
1854: /* Don't set too many environment variables */
1855: if (s->num_env > 128) {
1856: debug2("Ignoring env request %s: too many env vars", name);
1857: goto fail;
1858: }
1859:
1860: for (i = 0; i < options.num_accept_env; i++) {
1861: if (match_pattern(name, options.accept_env[i])) {
1862: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.201 djm 1863: s->env = xrealloc(s->env, s->num_env + 1,
1864: sizeof(*s->env));
1.173 djm 1865: s->env[s->num_env].name = name;
1866: s->env[s->num_env].val = val;
1867: s->num_env++;
1868: return (1);
1869: }
1870: }
1871: debug2("Ignoring env request %s: disallowed name", name);
1872:
1873: fail:
1.265 djm 1874: free(name);
1875: free(val);
1.173 djm 1876: return (0);
1877: }
1878:
1879: static int
1.43 markus 1880: session_auth_agent_req(Session *s)
1881: {
1882: static int called = 0;
1.116 markus 1883: packet_check_eom();
1.235 pyr 1884: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1885: debug("session_auth_agent_req: no_agent_forwarding_flag");
1886: return 0;
1887: }
1.43 markus 1888: if (called) {
1889: return 0;
1890: } else {
1891: called = 1;
1892: return auth_input_request_forwarding(s->pw);
1893: }
1894: }
1895:
1.123 markus 1896: int
1897: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1898: {
1899: int success = 0;
1900: Session *s;
1901:
1.123 markus 1902: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1903: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1904: c->self, rtype);
1905: return 0;
1906: }
1907: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1908:
1909: /*
1.64 markus 1910: * a session is in LARVAL state until a shell, a command
1911: * or a subsystem is executed
1.2 markus 1912: */
1913: if (c->type == SSH_CHANNEL_LARVAL) {
1914: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1915: success = session_shell_req(s);
1.2 markus 1916: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1917: success = session_exec_req(s);
1.2 markus 1918: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1919: success = session_pty_req(s);
1.7 markus 1920: } else if (strcmp(rtype, "x11-req") == 0) {
1921: success = session_x11_req(s);
1.43 markus 1922: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1923: success = session_auth_agent_req(s);
1.7 markus 1924: } else if (strcmp(rtype, "subsystem") == 0) {
1925: success = session_subsystem_req(s);
1.173 djm 1926: } else if (strcmp(rtype, "env") == 0) {
1927: success = session_env_req(s);
1.2 markus 1928: }
1929: }
1930: if (strcmp(rtype, "window-change") == 0) {
1931: success = session_window_change_req(s);
1.177 djm 1932: } else if (strcmp(rtype, "break") == 0) {
1933: success = session_break_req(s);
1.2 markus 1934: }
1.177 djm 1935:
1.123 markus 1936: return success;
1.2 markus 1937: }
1938:
1939: void
1.256 djm 1940: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1941: int is_tty)
1.2 markus 1942: {
1943: if (!compat20)
1944: fatal("session_set_fds: called for proto != 2.0");
1945: /*
1946: * now that have a child and a pipe to the child,
1947: * we can activate our channel and register the fd's
1948: */
1949: if (s->chanid == -1)
1950: fatal("no channel for session %d", s->self);
1951: channel_set_fds(s->chanid,
1952: fdout, fdin, fderr,
1.256 djm 1953: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1954: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1955: }
1956:
1.85 markus 1957: /*
1958: * Function to perform pty cleanup. Also called if we get aborted abnormally
1959: * (e.g., due to a dropped connection).
1960: */
1.130 provos 1961: void
1.165 markus 1962: session_pty_cleanup2(Session *s)
1.1 markus 1963: {
1.85 markus 1964: if (s == NULL) {
1965: error("session_pty_cleanup: no session");
1966: return;
1967: }
1968: if (s->ttyfd == -1)
1.1 markus 1969: return;
1970:
1.54 stevesk 1971: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1972:
1973: /* Record that the user has logged out. */
1.85 markus 1974: if (s->pid != 0)
1975: record_logout(s->pid, s->tty);
1.1 markus 1976:
1977: /* Release the pseudo-tty. */
1.130 provos 1978: if (getuid() == 0)
1979: pty_release(s->tty);
1.1 markus 1980:
1981: /*
1982: * Close the server side of the socket pairs. We must do this after
1983: * the pty cleanup, so that another process doesn't get this pty
1984: * while we're still cleaning up.
1985: */
1.237 djm 1986: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
1987: error("close(s->ptymaster/%d): %s",
1988: s->ptymaster, strerror(errno));
1.108 markus 1989:
1990: /* unlink pty from session */
1991: s->ttyfd = -1;
1.2 markus 1992: }
1993:
1.130 provos 1994: void
1.165 markus 1995: session_pty_cleanup(Session *s)
1.130 provos 1996: {
1.165 markus 1997: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 1998: }
1999:
1.147 markus 2000: static char *
2001: sig2name(int sig)
2002: {
2003: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2004: SSH_SIG(ABRT);
2005: SSH_SIG(ALRM);
2006: SSH_SIG(FPE);
2007: SSH_SIG(HUP);
2008: SSH_SIG(ILL);
2009: SSH_SIG(INT);
2010: SSH_SIG(KILL);
2011: SSH_SIG(PIPE);
2012: SSH_SIG(QUIT);
2013: SSH_SIG(SEGV);
2014: SSH_SIG(TERM);
2015: SSH_SIG(USR1);
2016: SSH_SIG(USR2);
2017: #undef SSH_SIG
2018: return "SIG@openssh.com";
2019: }
2020:
1.94 itojun 2021: static void
1.184 djm 2022: session_close_x11(int id)
2023: {
2024: Channel *c;
2025:
1.189 markus 2026: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2027: debug("session_close_x11: x11 channel %d missing", id);
2028: } else {
2029: /* Detach X11 listener */
2030: debug("session_close_x11: detach x11 channel %d", id);
2031: channel_cancel_cleanup(id);
2032: if (c->ostate != CHAN_OUTPUT_CLOSED)
2033: chan_mark_dead(c);
2034: }
2035: }
2036:
2037: static void
2038: session_close_single_x11(int id, void *arg)
2039: {
2040: Session *s;
2041: u_int i;
2042:
2043: debug3("session_close_single_x11: channel %d", id);
2044: channel_cancel_cleanup(id);
1.221 stevesk 2045: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2046: fatal("session_close_single_x11: no x11 channel %d", id);
2047: for (i = 0; s->x11_chanids[i] != -1; i++) {
2048: debug("session_close_single_x11: session %d: "
2049: "closing channel %d", s->self, s->x11_chanids[i]);
2050: /*
2051: * The channel "id" is already closing, but make sure we
2052: * close all of its siblings.
2053: */
2054: if (s->x11_chanids[i] != id)
2055: session_close_x11(s->x11_chanids[i]);
2056: }
1.265 djm 2057: free(s->x11_chanids);
1.184 djm 2058: s->x11_chanids = NULL;
1.265 djm 2059: free(s->display);
2060: s->display = NULL;
2061: free(s->auth_proto);
2062: s->auth_proto = NULL;
2063: free(s->auth_data);
2064: s->auth_data = NULL;
2065: free(s->auth_display);
2066: s->auth_display = NULL;
1.184 djm 2067: }
2068:
2069: static void
1.2 markus 2070: session_exit_message(Session *s, int status)
2071: {
2072: Channel *c;
1.124 markus 2073:
2074: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2075: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2076: s->self, s->chanid);
1.137 mpech 2077: debug("session_exit_message: session %d channel %d pid %ld",
2078: s->self, s->chanid, (long)s->pid);
1.2 markus 2079:
2080: if (WIFEXITED(status)) {
1.124 markus 2081: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2082: packet_put_int(WEXITSTATUS(status));
2083: packet_send();
2084: } else if (WIFSIGNALED(status)) {
1.124 markus 2085: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2086: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2087: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2088: packet_put_cstring("");
2089: packet_put_cstring("");
2090: packet_send();
2091: } else {
2092: /* Some weird exit cause. Just exit. */
2093: packet_disconnect("wait returned status %04x.", status);
2094: }
2095:
2096: /* disconnect channel */
2097: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2098:
2099: /*
2100: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2101: * the channel gets EOF. The session will be then be closed
1.187 djm 2102: * by session_close_by_channel when the childs close their fds.
2103: */
2104: channel_register_cleanup(c->self, session_close_by_channel, 1);
2105:
1.5 markus 2106: /*
2107: * emulate a write failure with 'chan_write_failed', nobody will be
2108: * interested in data we write.
2109: * Note that we must not call 'chan_read_failed', since there could
2110: * be some more data waiting in the pipe.
2111: */
1.8 markus 2112: if (c->ostate != CHAN_OUTPUT_CLOSED)
2113: chan_write_failed(c);
1.2 markus 2114: }
2115:
1.130 provos 2116: void
1.85 markus 2117: session_close(Session *s)
1.2 markus 2118: {
1.182 djm 2119: u_int i;
1.173 djm 2120:
1.137 mpech 2121: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165 markus 2122: if (s->ttyfd != -1)
1.85 markus 2123: session_pty_cleanup(s);
1.265 djm 2124: free(s->term);
2125: free(s->display);
2126: free(s->x11_chanids);
2127: free(s->auth_display);
2128: free(s->auth_data);
2129: free(s->auth_proto);
1.267 djm 2130: free(s->subsys);
1.219 djm 2131: if (s->env != NULL) {
2132: for (i = 0; i < s->num_env; i++) {
1.265 djm 2133: free(s->env[i].name);
2134: free(s->env[i].val);
1.219 djm 2135: }
1.265 djm 2136: free(s->env);
1.173 djm 2137: }
1.9 markus 2138: session_proctitle(s);
1.237 djm 2139: session_unused(s->self);
1.2 markus 2140: }
2141:
2142: void
2143: session_close_by_pid(pid_t pid, int status)
2144: {
2145: Session *s = session_by_pid(pid);
2146: if (s == NULL) {
1.137 mpech 2147: debug("session_close_by_pid: no session for pid %ld",
2148: (long)pid);
1.2 markus 2149: return;
2150: }
2151: if (s->chanid != -1)
2152: session_exit_message(s, status);
1.187 djm 2153: if (s->ttyfd != -1)
2154: session_pty_cleanup(s);
1.197 djm 2155: s->pid = 0;
1.98 markus 2156: }
2157:
1.2 markus 2158: /*
2159: * this is called when a channel dies before
2160: * the session 'child' itself dies
2161: */
2162: void
2163: session_close_by_channel(int id, void *arg)
2164: {
2165: Session *s = session_by_channel(id);
1.187 djm 2166: u_int i;
1.184 djm 2167:
1.2 markus 2168: if (s == NULL) {
1.107 markus 2169: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2170: return;
2171: }
1.137 mpech 2172: debug("session_close_by_channel: channel %d child %ld",
2173: id, (long)s->pid);
1.107 markus 2174: if (s->pid != 0) {
2175: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2176: /*
2177: * delay detach of session, but release pty, since
2178: * the fd's to the child are already closed
2179: */
1.165 markus 2180: if (s->ttyfd != -1)
1.108 markus 2181: session_pty_cleanup(s);
1.107 markus 2182: return;
2183: }
2184: /* detach by removing callback */
1.2 markus 2185: channel_cancel_cleanup(s->chanid);
1.187 djm 2186:
2187: /* Close any X11 listeners associated with this session */
2188: if (s->x11_chanids != NULL) {
2189: for (i = 0; s->x11_chanids[i] != -1; i++) {
2190: session_close_x11(s->x11_chanids[i]);
2191: s->x11_chanids[i] = -1;
2192: }
2193: }
2194:
1.2 markus 2195: s->chanid = -1;
1.106 markus 2196: session_close(s);
2197: }
2198:
2199: void
1.130 provos 2200: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2201: {
2202: int i;
1.237 djm 2203: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2204: Session *s = &sessions[i];
1.130 provos 2205: if (s->used) {
2206: if (closefunc != NULL)
2207: closefunc(s);
2208: else
2209: session_close(s);
2210: }
1.2 markus 2211: }
1.9 markus 2212: }
2213:
1.94 itojun 2214: static char *
1.9 markus 2215: session_tty_list(void)
2216: {
2217: static char buf[1024];
2218: int i;
2219: buf[0] = '\0';
1.237 djm 2220: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2221: Session *s = &sessions[i];
2222: if (s->used && s->ttyfd != -1) {
2223: if (buf[0] != '\0')
2224: strlcat(buf, ",", sizeof buf);
2225: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2226: }
2227: }
2228: if (buf[0] == '\0')
2229: strlcpy(buf, "notty", sizeof buf);
2230: return buf;
2231: }
2232:
2233: void
2234: session_proctitle(Session *s)
2235: {
2236: if (s->pw == NULL)
2237: error("no user for session %d", s->self);
2238: else
2239: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2240: }
2241:
2242: int
2243: session_setup_x11fwd(Session *s)
2244: {
2245: struct stat st;
1.109 stevesk 2246: char display[512], auth_display[512];
1.272 djm 2247: char hostname[NI_MAXHOST];
1.184 djm 2248: u_int i;
1.81 markus 2249:
2250: if (no_x11_forwarding_flag) {
2251: packet_send_debug("X11 forwarding disabled in user configuration file.");
2252: return 0;
2253: }
2254: if (!options.x11_forwarding) {
2255: debug("X11 forwarding disabled in server configuration file.");
2256: return 0;
2257: }
1.275 djm 2258: if (options.xauth_location == NULL ||
1.81 markus 2259: (stat(options.xauth_location, &st) == -1)) {
2260: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2261: return 0;
2262: }
2263: if (options.use_login) {
2264: packet_send_debug("X11 forwarding disabled; "
2265: "not compatible with UseLogin=yes.");
1.81 markus 2266: return 0;
2267: }
1.87 markus 2268: if (s->display != NULL) {
1.81 markus 2269: debug("X11 display already set.");
2270: return 0;
2271: }
1.140 deraadt 2272: if (x11_create_display_inet(options.x11_display_offset,
2273: options.x11_use_localhost, s->single_connection,
1.184 djm 2274: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2275: debug("x11_create_display_inet failed.");
1.81 markus 2276: return 0;
1.184 djm 2277: }
2278: for (i = 0; s->x11_chanids[i] != -1; i++) {
2279: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2280: session_close_single_x11, 0);
1.81 markus 2281: }
1.109 stevesk 2282:
2283: /* Set up a suitable value for the DISPLAY variable. */
2284: if (gethostname(hostname, sizeof(hostname)) < 0)
2285: fatal("gethostname: %.100s", strerror(errno));
2286: /*
2287: * auth_display must be used as the displayname when the
2288: * authorization entry is added with xauth(1). This will be
2289: * different than the DISPLAY string for localhost displays.
2290: */
1.119 stevesk 2291: if (options.x11_use_localhost) {
1.140 deraadt 2292: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2293: s->display_number, s->screen);
1.140 deraadt 2294: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2295: s->display_number, s->screen);
1.109 stevesk 2296: s->display = xstrdup(display);
1.118 stevesk 2297: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2298: } else {
1.140 deraadt 2299: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2300: s->display_number, s->screen);
2301: s->display = xstrdup(display);
1.118 stevesk 2302: s->auth_display = xstrdup(display);
1.109 stevesk 2303: }
2304:
1.81 markus 2305: return 1;
1.2 markus 2306: }
2307:
1.94 itojun 2308: static void
1.49 markus 2309: do_authenticated2(Authctxt *authctxt)
1.2 markus 2310: {
1.97 markus 2311: server_loop2(authctxt);
1.165 markus 2312: }
2313:
2314: void
2315: do_cleanup(Authctxt *authctxt)
2316: {
2317: static int called = 0;
2318:
2319: debug("do_cleanup");
2320:
2321: /* no cleanup if we're in the child for login shell */
2322: if (is_child)
2323: return;
2324:
2325: /* avoid double cleanup */
2326: if (called)
2327: return;
2328: called = 1;
2329:
1.218 markus 2330: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2331: return;
2332: #ifdef KRB5
2333: if (options.kerberos_ticket_cleanup &&
2334: authctxt->krb5_ctx)
2335: krb5_cleanup_proc(authctxt);
1.161 markus 2336: #endif
1.165 markus 2337:
2338: #ifdef GSSAPI
2339: if (compat20 && options.gss_cleanup_creds)
2340: ssh_gssapi_cleanup_creds();
2341: #endif
2342:
2343: /* remove agent socket */
2344: auth_sock_cleanup_proc(authctxt->pw);
2345:
2346: /*
2347: * Cleanup ptys/utmp only if privsep is disabled,
2348: * or if running in monitor.
2349: */
2350: if (!use_privsep || mm_is_monitor())
2351: session_destroy_all(session_pty_cleanup2);
1.1 markus 2352: }
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