Annotation of src/usr.bin/ssh/session.c, Revision 1.279
1.279 ! djm 1: /* $OpenBSD: session.c,v 1.278 2015/04/24 01:36:00 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:
1.209 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;
1.279 ! djm 145: static int in_chroot = 0;
1.165 markus 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:
1.1 markus 259: /*
260: * Prepares for an interactive session. This is called after the user has
261: * been successfully authenticated. During this message exchange, pseudo
262: * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
263: * are requested, etc.
264: */
1.94 itojun 265: static void
1.65 markus 266: do_authenticated1(Authctxt *authctxt)
1.1 markus 267: {
268: Session *s;
1.65 markus 269: char *command;
1.117 markus 270: int success, type, screen_flag;
1.139 deraadt 271: int enable_compression_after_reply = 0;
272: u_int proto_len, data_len, dlen, compression_level = 0;
1.1 markus 273:
1.61 markus 274: s = session_new();
1.181 markus 275: if (s == NULL) {
276: error("no more sessions");
277: return;
278: }
1.96 dugsong 279: s->authctxt = authctxt;
1.65 markus 280: s->pw = authctxt->pw;
1.28 millert 281:
1.1 markus 282: /*
283: * We stay in this loop until the client requests to execute a shell
284: * or a command.
285: */
286: for (;;) {
1.65 markus 287: success = 0;
1.1 markus 288:
289: /* Get a packet from the client. */
1.117 markus 290: type = packet_read();
1.1 markus 291:
292: /* Process the packet. */
293: switch (type) {
294: case SSH_CMSG_REQUEST_COMPRESSION:
295: compression_level = packet_get_int();
1.116 markus 296: packet_check_eom();
1.1 markus 297: if (compression_level < 1 || compression_level > 9) {
1.180 markus 298: packet_send_debug("Received invalid compression level %d.",
1.112 deraadt 299: compression_level);
1.138 markus 300: break;
301: }
1.186 markus 302: if (options.compression == COMP_NONE) {
1.138 markus 303: debug2("compression disabled");
1.1 markus 304: break;
305: }
306: /* Enable compression after we have responded with SUCCESS. */
307: enable_compression_after_reply = 1;
308: success = 1;
309: break;
310:
311: case SSH_CMSG_REQUEST_PTY:
1.86 markus 312: success = session_pty_req(s);
1.1 markus 313: break;
314:
315: case SSH_CMSG_X11_REQUEST_FORWARDING:
316: s->auth_proto = packet_get_string(&proto_len);
317: s->auth_data = packet_get_string(&data_len);
318:
1.57 markus 319: screen_flag = packet_get_protocol_flags() &
320: SSH_PROTOFLAG_SCREEN_NUMBER;
321: debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
322:
323: if (packet_remaining() == 4) {
324: if (!screen_flag)
325: debug2("Buggy client: "
326: "X11 screen flag missing");
1.1 markus 327: s->screen = packet_get_int();
1.56 markus 328: } else {
1.1 markus 329: s->screen = 0;
1.56 markus 330: }
1.116 markus 331: packet_check_eom();
1.81 markus 332: success = session_setup_x11fwd(s);
333: if (!success) {
1.265 djm 334: free(s->auth_proto);
335: free(s->auth_data);
1.84 markus 336: s->auth_proto = NULL;
337: s->auth_data = NULL;
1.1 markus 338: }
339: break;
340:
341: case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1.235 pyr 342: if (!options.allow_agent_forwarding ||
343: no_agent_forwarding_flag || compat13) {
1.1 markus 344: debug("Authentication agent forwarding not permitted for this authentication.");
345: break;
346: }
347: debug("Received authentication agent forwarding request.");
1.65 markus 348: success = auth_input_request_forwarding(s->pw);
1.1 markus 349: break;
350:
351: case SSH_CMSG_PORT_FORWARD_REQUEST:
352: if (no_port_forwarding_flag) {
353: debug("Port forwarding not permitted for this authentication.");
1.39 markus 354: break;
355: }
1.261 djm 356: if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
1.39 markus 357: debug("Port forwarding not permitted.");
1.1 markus 358: break;
359: }
360: debug("Received TCP/IP port forwarding request.");
1.208 markus 361: if (channel_input_port_forward_request(s->pw->pw_uid == 0,
1.274 millert 362: &options.fwd_opts) < 0) {
1.208 markus 363: debug("Port forwarding failed.");
364: break;
365: }
1.1 markus 366: success = 1;
367: break;
368:
369: case SSH_CMSG_MAX_PACKET_SIZE:
370: if (packet_set_maxsize(packet_get_int()) > 0)
371: success = 1;
372: break;
373:
374: case SSH_CMSG_EXEC_SHELL:
375: case SSH_CMSG_EXEC_CMD:
376: if (type == SSH_CMSG_EXEC_CMD) {
377: command = packet_get_string(&dlen);
378: debug("Exec command '%.500s'", command);
1.237 djm 379: if (do_exec(s, command) != 0)
380: packet_disconnect(
381: "command execution failed");
1.265 djm 382: free(command);
1.1 markus 383: } else {
1.237 djm 384: if (do_exec(s, NULL) != 0)
385: packet_disconnect(
386: "shell execution failed");
1.1 markus 387: }
1.116 markus 388: packet_check_eom();
1.82 markus 389: session_close(s);
1.1 markus 390: return;
391:
392: default:
393: /*
394: * Any unknown messages in this phase are ignored,
395: * and a failure message is returned.
396: */
1.155 itojun 397: logit("Unknown packet type received after authentication: %d", type);
1.1 markus 398: }
399: packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
400: packet_send();
401: packet_write_wait();
402:
403: /* Enable compression now that we have replied if appropriate. */
404: if (enable_compression_after_reply) {
405: enable_compression_after_reply = 0;
406: packet_start_compression(compression_level);
407: }
408: }
409: }
410:
1.269 dtucker 411: #define USE_PIPES 1
1.1 markus 412: /*
413: * This is called to fork and execute a command when we have no tty. This
414: * will call do_child from the child, and server_loop from the parent after
415: * setting up file descriptors and such.
416: */
1.237 djm 417: int
1.63 markus 418: do_exec_no_pty(Session *s, const char *command)
1.1 markus 419: {
1.137 mpech 420: pid_t pid;
1.238 markus 421: #ifdef USE_PIPES
422: int pin[2], pout[2], perr[2];
423:
1.253 djm 424: if (s == NULL)
425: fatal("do_exec_no_pty: no session");
426:
1.238 markus 427: /* Allocate pipes for communicating with the program. */
428: if (pipe(pin) < 0) {
429: error("%s: pipe in: %.100s", __func__, strerror(errno));
430: return -1;
431: }
432: if (pipe(pout) < 0) {
433: error("%s: pipe out: %.100s", __func__, strerror(errno));
434: close(pin[0]);
435: close(pin[1]);
436: return -1;
437: }
1.256 djm 438: if (pipe(perr) < 0) {
439: error("%s: pipe err: %.100s", __func__,
440: strerror(errno));
441: close(pin[0]);
442: close(pin[1]);
443: close(pout[0]);
444: close(pout[1]);
445: return -1;
1.238 markus 446: }
447: #else
1.237 djm 448: int inout[2], err[2];
1.1 markus 449:
1.253 djm 450: if (s == NULL)
451: fatal("do_exec_no_pty: no session");
452:
1.1 markus 453: /* Uses socket pairs to communicate with the program. */
1.237 djm 454: if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
455: error("%s: socketpair #1: %.100s", __func__, strerror(errno));
456: return -1;
457: }
1.256 djm 458: if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
459: error("%s: socketpair #2: %.100s", __func__,
460: strerror(errno));
461: close(inout[0]);
462: close(inout[1]);
463: return -1;
1.237 djm 464: }
1.238 markus 465: #endif
1.237 djm 466:
1.9 markus 467: session_proctitle(s);
1.1 markus 468:
469: /* Fork the child. */
1.237 djm 470: switch ((pid = fork())) {
471: case -1:
472: error("%s: fork: %.100s", __func__, strerror(errno));
1.238 markus 473: #ifdef USE_PIPES
474: close(pin[0]);
475: close(pin[1]);
476: close(pout[0]);
477: close(pout[1]);
1.256 djm 478: close(perr[0]);
1.238 markus 479: close(perr[1]);
480: #else
1.237 djm 481: close(inout[0]);
482: close(inout[1]);
483: close(err[0]);
1.256 djm 484: close(err[1]);
1.238 markus 485: #endif
1.237 djm 486: return -1;
487: case 0:
1.165 markus 488: is_child = 1;
1.144 markus 489:
1.1 markus 490: /* Child. Reinitialize the log since the pid has changed. */
1.237 djm 491: log_init(__progname, options.log_level,
492: options.log_facility, log_stderr);
1.1 markus 493:
494: /*
495: * Create a new session and process group since the 4.4BSD
496: * setlogin() affects the entire process group.
497: */
498: if (setsid() < 0)
499: error("setsid failed: %.100s", strerror(errno));
500:
1.238 markus 501: #ifdef USE_PIPES
502: /*
503: * Redirect stdin. We close the parent side of the socket
504: * pair, and make the child side the standard input.
505: */
506: close(pin[1]);
507: if (dup2(pin[0], 0) < 0)
508: perror("dup2 stdin");
509: close(pin[0]);
510:
511: /* Redirect stdout. */
512: close(pout[0]);
513: if (dup2(pout[1], 1) < 0)
514: perror("dup2 stdout");
515: close(pout[1]);
516:
517: /* Redirect stderr. */
1.256 djm 518: close(perr[0]);
1.238 markus 519: if (dup2(perr[1], 2) < 0)
520: perror("dup2 stderr");
521: close(perr[1]);
522: #else
1.1 markus 523: /*
524: * Redirect stdin, stdout, and stderr. Stdin and stdout will
525: * use the same socket, as some programs (particularly rdist)
526: * seem to depend on it.
527: */
528: close(inout[1]);
1.256 djm 529: close(err[1]);
1.1 markus 530: if (dup2(inout[0], 0) < 0) /* stdin */
531: perror("dup2 stdin");
1.237 djm 532: if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
1.1 markus 533: perror("dup2 stdout");
1.238 markus 534: close(inout[0]);
1.1 markus 535: if (dup2(err[0], 2) < 0) /* stderr */
536: perror("dup2 stderr");
1.238 markus 537: close(err[0]);
538: #endif
1.1 markus 539:
540: /* Do processing for the child (exec command etc). */
1.60 markus 541: do_child(s, command);
1.1 markus 542: /* NOTREACHED */
1.237 djm 543: default:
544: break;
1.1 markus 545: }
1.237 djm 546:
1.1 markus 547: s->pid = pid;
1.47 markus 548: /* Set interactive/non-interactive mode. */
1.257 djm 549: packet_set_interactive(s->display != NULL,
550: options.ip_qos_interactive, options.ip_qos_bulk);
1.1 markus 551:
1.238 markus 552: #ifdef USE_PIPES
553: /* We are the parent. Close the child sides of the pipes. */
554: close(pin[0]);
555: close(pout[1]);
556: close(perr[1]);
557:
558: if (compat20) {
1.256 djm 559: session_set_fds(s, pin[1], pout[0], perr[0],
560: s->is_subsystem, 0);
1.238 markus 561: } else {
562: /* Enter the interactive session. */
563: server_loop(pid, pin[1], pout[0], perr[0]);
564: /* server_loop has closed pin[1], pout[0], and perr[0]. */
565: }
566: #else
1.1 markus 567: /* We are the parent. Close the child sides of the socket pairs. */
568: close(inout[0]);
569: close(err[0]);
570:
571: /*
572: * Enter the interactive session. Note: server_loop must be able to
573: * handle the case that fdin and fdout are the same.
574: */
1.2 markus 575: if (compat20) {
1.256 djm 576: session_set_fds(s, inout[1], inout[1], err[1],
577: s->is_subsystem, 0);
1.2 markus 578: } else {
579: server_loop(pid, inout[1], inout[1], err[1]);
580: /* server_loop has closed inout[1] and err[1]. */
581: }
1.238 markus 582: #endif
1.237 djm 583: return 0;
1.1 markus 584: }
585:
586: /*
587: * This is called to fork and execute a command when we have a tty. This
588: * will call do_child from the child, and server_loop from the parent after
589: * setting up file descriptors, controlling tty, updating wtmp, utmp,
590: * lastlog, and other such operations.
591: */
1.237 djm 592: int
1.63 markus 593: do_exec_pty(Session *s, const char *command)
1.1 markus 594: {
595: int fdout, ptyfd, ttyfd, ptymaster;
596: pid_t pid;
597:
598: if (s == NULL)
599: fatal("do_exec_pty: no session");
600: ptyfd = s->ptyfd;
601: ttyfd = s->ttyfd;
602:
1.237 djm 603: /*
604: * Create another descriptor of the pty master side for use as the
605: * standard input. We could use the original descriptor, but this
606: * simplifies code in server_loop. The descriptor is bidirectional.
607: * Do this before forking (and cleanup in the child) so as to
608: * detect and gracefully fail out-of-fd conditions.
609: */
610: if ((fdout = dup(ptyfd)) < 0) {
611: error("%s: dup #1: %s", __func__, strerror(errno));
612: close(ttyfd);
613: close(ptyfd);
614: return -1;
615: }
616: /* we keep a reference to the pty master */
617: if ((ptymaster = dup(ptyfd)) < 0) {
618: error("%s: dup #2: %s", __func__, strerror(errno));
619: close(ttyfd);
620: close(ptyfd);
621: close(fdout);
622: return -1;
623: }
624:
1.1 markus 625: /* Fork the child. */
1.237 djm 626: switch ((pid = fork())) {
627: case -1:
628: error("%s: fork: %.100s", __func__, strerror(errno));
629: close(fdout);
630: close(ptymaster);
631: close(ttyfd);
632: close(ptyfd);
633: return -1;
634: case 0:
1.165 markus 635: is_child = 1;
1.97 markus 636:
1.237 djm 637: close(fdout);
638: close(ptymaster);
639:
1.24 markus 640: /* Child. Reinitialize the log because the pid has changed. */
1.237 djm 641: log_init(__progname, options.log_level,
642: options.log_facility, log_stderr);
1.1 markus 643: /* Close the master side of the pseudo tty. */
644: close(ptyfd);
645:
646: /* Make the pseudo tty our controlling tty. */
647: pty_make_controlling_tty(&ttyfd, s->tty);
648:
1.103 markus 649: /* Redirect stdin/stdout/stderr from the pseudo tty. */
650: if (dup2(ttyfd, 0) < 0)
651: error("dup2 stdin: %s", strerror(errno));
652: if (dup2(ttyfd, 1) < 0)
653: error("dup2 stdout: %s", strerror(errno));
654: if (dup2(ttyfd, 2) < 0)
655: error("dup2 stderr: %s", strerror(errno));
1.1 markus 656:
657: /* Close the extra descriptor for the pseudo tty. */
658: close(ttyfd);
659:
1.24 markus 660: /* record login, etc. similar to login(1) */
1.41 markus 661: if (!(options.use_login && command == NULL))
662: do_login(s, command);
1.228 djm 663:
1.237 djm 664: /*
665: * Do common processing for the child, such as execing
666: * the command.
667: */
1.60 markus 668: do_child(s, command);
1.1 markus 669: /* NOTREACHED */
1.237 djm 670: default:
671: break;
1.1 markus 672: }
673: s->pid = pid;
674:
675: /* Parent. Close the slave side of the pseudo tty. */
676: close(ttyfd);
677:
1.237 djm 678: /* Enter interactive session. */
1.1 markus 679: s->ptymaster = ptymaster;
1.257 djm 680: packet_set_interactive(1,
681: options.ip_qos_interactive, options.ip_qos_bulk);
1.2 markus 682: if (compat20) {
1.256 djm 683: session_set_fds(s, ptyfd, fdout, -1, 1, 1);
1.2 markus 684: } else {
685: server_loop(pid, ptyfd, fdout, -1);
686: /* server_loop _has_ closed ptyfd and fdout. */
1.24 markus 687: }
1.237 djm 688: return 0;
1.24 markus 689: }
690:
1.90 markus 691: /*
692: * This is called to fork and execute a command. If another command is
693: * to be forced, execute that instead.
694: */
1.237 djm 695: int
1.90 markus 696: do_exec(Session *s, const char *command)
697: {
1.237 djm 698: int ret;
1.267 djm 699: const char *forced = NULL;
700: char session_type[1024], *tty = NULL;
1.237 djm 701:
1.210 dtucker 702: if (options.adm_forced_command) {
703: original_command = command;
704: command = options.adm_forced_command;
1.267 djm 705: forced = "(config)";
1.210 dtucker 706: } else if (forced_command) {
1.90 markus 707: original_command = command;
708: command = forced_command;
1.267 djm 709: forced = "(key-option)";
710: }
711: if (forced != NULL) {
1.248 djm 712: if (IS_INTERNAL_SFTP(command)) {
713: s->is_subsystem = s->is_subsystem ?
714: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
715: } else if (s->is_subsystem)
1.225 markus 716: s->is_subsystem = SUBSYSTEM_EXT;
1.267 djm 717: snprintf(session_type, sizeof(session_type),
718: "forced-command %s '%.900s'", forced, command);
719: } else if (s->is_subsystem) {
720: snprintf(session_type, sizeof(session_type),
721: "subsystem '%.900s'", s->subsys);
722: } else if (command == NULL) {
723: snprintf(session_type, sizeof(session_type), "shell");
724: } else {
725: /* NB. we don't log unforced commands to preserve privacy */
726: snprintf(session_type, sizeof(session_type), "command");
1.90 markus 727: }
1.163 markus 728:
1.267 djm 729: if (s->ttyfd != -1) {
730: tty = s->tty;
731: if (strncmp(tty, "/dev/", 5) == 0)
732: tty += 5;
733: }
734:
735: verbose("Starting session: %s%s%s for %s from %.200s port %d",
736: session_type,
737: tty == NULL ? "" : " on ",
738: tty == NULL ? "" : tty,
739: s->pw->pw_name,
740: get_remote_ipaddr(),
741: get_remote_port());
742:
1.163 markus 743: #ifdef GSSAPI
744: if (options.gss_authentication) {
745: temporarily_use_uid(s->pw);
746: ssh_gssapi_storecreds();
747: restore_uid();
748: }
749: #endif
1.90 markus 750: if (s->ttyfd != -1)
1.237 djm 751: ret = do_exec_pty(s, command);
1.90 markus 752: else
1.237 djm 753: ret = do_exec_no_pty(s, command);
1.90 markus 754:
1.92 markus 755: original_command = NULL;
1.179 dtucker 756:
757: /*
758: * Clear loginmsg: it's the child's responsibility to display
759: * it to the user, otherwise multiple sessions may accumulate
760: * multiple copies of the login messages.
761: */
762: buffer_clear(&loginmsg);
1.237 djm 763:
764: return ret;
1.90 markus 765: }
766:
767:
1.24 markus 768: /* administrative, login(1)-like work */
769: void
1.41 markus 770: do_login(Session *s, const char *command)
1.24 markus 771: {
772: socklen_t fromlen;
773: struct sockaddr_storage from;
774: struct passwd * pw = s->pw;
775: pid_t pid = getpid();
776:
777: /*
778: * Get IP address of client. If the connection is not a socket, let
779: * the address be 0.0.0.0.
780: */
781: memset(&from, 0, sizeof(from));
1.148 stevesk 782: fromlen = sizeof(from);
1.24 markus 783: if (packet_connection_is_on_socket()) {
784: if (getpeername(packet_get_connection_in(),
1.200 deraadt 785: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 786: debug("getpeername: %.100s", strerror(errno));
1.165 markus 787: cleanup_exit(255);
1.24 markus 788: }
789: }
1.25 markus 790:
1.24 markus 791: /* Record that there was a login on that tty from the remote host. */
1.133 markus 792: if (!use_privsep)
793: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
794: get_remote_name_or_ip(utmp_len,
1.158 markus 795: options.use_dns),
1.148 stevesk 796: (struct sockaddr *)&from, fromlen);
1.24 markus 797:
1.73 djm 798: if (check_quietlogin(s, command))
1.24 markus 799: return;
1.73 djm 800:
1.179 dtucker 801: display_loginmsg();
1.73 djm 802:
803: do_motd();
804: }
805:
806: /*
807: * Display the message of the day.
808: */
809: void
810: do_motd(void)
811: {
812: FILE *f;
813: char buf[256];
814:
1.24 markus 815: if (options.print_motd) {
1.28 millert 816: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
817: "/etc/motd"), "r");
1.24 markus 818: if (f) {
819: while (fgets(buf, sizeof(buf), f))
820: fputs(buf, stdout);
821: fclose(f);
822: }
1.2 markus 823: }
1.73 djm 824: }
825:
826:
827: /*
828: * Check for quiet login, either .hushlogin or command given.
829: */
830: int
831: check_quietlogin(Session *s, const char *command)
832: {
833: char buf[256];
1.96 dugsong 834: struct passwd *pw = s->pw;
1.73 djm 835: struct stat st;
836:
837: /* Return 1 if .hushlogin exists or a command given. */
838: if (command != NULL)
839: return 1;
840: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
841: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
842: return 1;
843: return 0;
1.1 markus 844: }
845:
846: /*
847: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 848: * already exists, its value is overridden.
1.1 markus 849: */
1.161 markus 850: void
1.45 markus 851: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 852: const char *value)
1.1 markus 853: {
1.164 markus 854: char **env;
855: u_int envsize;
1.45 markus 856: u_int i, namelen;
1.1 markus 857:
1.271 djm 858: if (strchr(name, '=') != NULL) {
859: error("Invalid environment variable \"%.100s\"", name);
860: return;
861: }
862:
1.1 markus 863: /*
864: * Find the slot where the value should be stored. If the variable
865: * already exists, we reuse the slot; otherwise we append a new slot
866: * at the end of the array, expanding if necessary.
867: */
868: env = *envp;
869: namelen = strlen(name);
870: for (i = 0; env[i]; i++)
871: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
872: break;
873: if (env[i]) {
874: /* Reuse the slot. */
1.265 djm 875: free(env[i]);
1.1 markus 876: } else {
877: /* New variable. Expand if necessary. */
1.164 markus 878: envsize = *envsizep;
879: if (i >= envsize - 1) {
880: if (envsize >= 1000)
881: fatal("child_set_env: too many env vars");
882: envsize += 50;
1.278 deraadt 883: env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1.164 markus 884: *envsizep = envsize;
1.1 markus 885: }
886: /* Need to set the NULL pointer at end of array beyond the new slot. */
887: env[i + 1] = NULL;
888: }
889:
890: /* Allocate space and format the variable in the appropriate slot. */
891: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
892: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
893: }
894:
895: /*
896: * Reads environment variables from the given file and adds/overrides them
897: * into the environment. If the file does not exist, this does nothing.
898: * Otherwise, it must consist of empty lines, comments (line starts with '#')
899: * and assignments of the form name=value. No other forms are allowed.
900: */
1.94 itojun 901: static void
1.45 markus 902: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 903: const char *filename)
1.1 markus 904: {
905: FILE *f;
906: char buf[4096];
907: char *cp, *value;
1.142 deraadt 908: u_int lineno = 0;
1.1 markus 909:
910: f = fopen(filename, "r");
911: if (!f)
912: return;
913:
914: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 915: if (++lineno > 1000)
916: fatal("Too many lines in environment file %s", filename);
1.1 markus 917: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
918: ;
919: if (!*cp || *cp == '#' || *cp == '\n')
920: continue;
1.224 gilles 921:
922: cp[strcspn(cp, "\n")] = '\0';
923:
1.1 markus 924: value = strchr(cp, '=');
925: if (value == NULL) {
1.142 deraadt 926: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
927: filename);
1.1 markus 928: continue;
929: }
1.14 deraadt 930: /*
931: * Replace the equals sign by nul, and advance value to
932: * the value string.
933: */
1.1 markus 934: *value = '\0';
935: value++;
936: child_set_env(env, envsize, cp, value);
937: }
938: fclose(f);
939: }
940:
1.127 markus 941: static char **
942: do_setup_env(Session *s, const char *shell)
1.1 markus 943: {
944: char buf[256];
1.127 markus 945: u_int i, envsize;
1.154 markus 946: char **env, *laddr;
1.127 markus 947: struct passwd *pw = s->pw;
1.1 markus 948:
949: /* Initialize the environment. */
950: envsize = 100;
1.220 djm 951: env = xcalloc(envsize, sizeof(char *));
1.1 markus 952: env[0] = NULL;
953:
1.161 markus 954: #ifdef GSSAPI
1.168 djm 955: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 956: * the childs environment as they see fit
957: */
958: ssh_gssapi_do_child(&env, &envsize);
959: #endif
960:
1.1 markus 961: if (!options.use_login) {
962: /* Set basic environment. */
1.173 djm 963: for (i = 0; i < s->num_env; i++)
1.178 deraadt 964: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 965: s->env[i].val);
966:
1.1 markus 967: child_set_env(&env, &envsize, "USER", pw->pw_name);
968: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
969: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 970: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
971: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
972: else
973: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 974:
975: snprintf(buf, sizeof buf, "%.200s/%.50s",
976: _PATH_MAILDIR, pw->pw_name);
977: child_set_env(&env, &envsize, "MAIL", buf);
978:
979: /* Normal systems set SHELL by default. */
980: child_set_env(&env, &envsize, "SHELL", shell);
981: }
982: if (getenv("TZ"))
983: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
984:
985: /* Set custom environment options from RSA authentication. */
1.110 markus 986: if (!options.use_login) {
987: while (custom_environment) {
988: struct envstring *ce = custom_environment;
1.143 deraadt 989: char *str = ce->s;
1.127 markus 990:
1.143 deraadt 991: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 992: ;
1.143 deraadt 993: if (str[i] == '=') {
994: str[i] = 0;
995: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 996: }
997: custom_environment = ce->next;
1.265 djm 998: free(ce->s);
999: free(ce);
1.1 markus 1000: }
1001: }
1002:
1.149 stevesk 1003: /* SSH_CLIENT deprecated */
1.1 markus 1004: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 1005: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 1006: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1007:
1.154 markus 1008: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1009: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 1010: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1.265 djm 1011: free(laddr);
1.149 stevesk 1012: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1013:
1.60 markus 1014: if (s->ttyfd != -1)
1015: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1016: if (s->term)
1017: child_set_env(&env, &envsize, "TERM", s->term);
1018: if (s->display)
1019: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1020: if (original_command)
1021: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1022: original_command);
1.96 dugsong 1023: #ifdef KRB5
1024: if (s->authctxt->krb5_ticket_file)
1025: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1026: s->authctxt->krb5_ticket_file);
1.96 dugsong 1027: #endif
1.136 markus 1028: if (auth_sock_name != NULL)
1.1 markus 1029: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1030: auth_sock_name);
1.1 markus 1031:
1032: /* read $HOME/.ssh/environment. */
1.146 markus 1033: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1034: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1035: pw->pw_dir);
1.1 markus 1036: read_environment_file(&env, &envsize, buf);
1037: }
1038: if (debug_flag) {
1039: /* dump the environment */
1040: fprintf(stderr, "Environment:\n");
1041: for (i = 0; env[i]; i++)
1042: fprintf(stderr, " %.200s\n", env[i]);
1043: }
1.127 markus 1044: return env;
1045: }
1046:
1047: /*
1048: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1049: * first in this order).
1050: */
1051: static void
1052: do_rc_files(Session *s, const char *shell)
1053: {
1054: FILE *f = NULL;
1055: char cmd[1024];
1056: int do_xauth;
1057: struct stat st;
1058:
1059: do_xauth =
1060: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1061:
1.231 djm 1062: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1063: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.273 djm 1064: !no_user_rc && options.permit_user_rc &&
1065: stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1066: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1067: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1068: if (debug_flag)
1069: fprintf(stderr, "Running %s\n", cmd);
1070: f = popen(cmd, "w");
1071: if (f) {
1072: if (do_xauth)
1073: fprintf(f, "%s %s\n", s->auth_proto,
1074: s->auth_data);
1075: pclose(f);
1076: } else
1077: fprintf(stderr, "Could not run %s\n",
1078: _PATH_SSH_USER_RC);
1079: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1080: if (debug_flag)
1081: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1082: _PATH_SSH_SYSTEM_RC);
1083: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1084: if (f) {
1085: if (do_xauth)
1086: fprintf(f, "%s %s\n", s->auth_proto,
1087: s->auth_data);
1088: pclose(f);
1089: } else
1090: fprintf(stderr, "Could not run %s\n",
1091: _PATH_SSH_SYSTEM_RC);
1092: } else if (do_xauth && options.xauth_location != NULL) {
1093: /* Add authority data to .Xauthority if appropriate. */
1094: if (debug_flag) {
1095: fprintf(stderr,
1.151 stevesk 1096: "Running %.500s remove %.100s\n",
1.165 markus 1097: options.xauth_location, s->auth_display);
1.151 stevesk 1098: fprintf(stderr,
1099: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1100: options.xauth_location, s->auth_display,
1101: s->auth_proto, s->auth_data);
1102: }
1103: snprintf(cmd, sizeof cmd, "%s -q -",
1104: options.xauth_location);
1105: f = popen(cmd, "w");
1106: if (f) {
1.151 stevesk 1107: fprintf(f, "remove %s\n",
1108: s->auth_display);
1.127 markus 1109: fprintf(f, "add %s %s %s\n",
1110: s->auth_display, s->auth_proto,
1111: s->auth_data);
1112: pclose(f);
1113: } else {
1114: fprintf(stderr, "Could not run %s\n",
1115: cmd);
1116: }
1117: }
1118: }
1119:
1120: static void
1121: do_nologin(struct passwd *pw)
1122: {
1123: FILE *f = NULL;
1.251 dtucker 1124: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1125: struct stat sb;
1.127 markus 1126:
1.260 guenther 1127: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1128: return;
1129: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1130:
1131: if (stat(nl, &sb) == -1) {
1132: if (nl != def_nl)
1.265 djm 1133: free(nl);
1.251 dtucker 1134: return;
1135: }
1136:
1137: /* /etc/nologin exists. Print its contents if we can and exit. */
1138: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1139: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1140: while (fgets(buf, sizeof(buf), f))
1141: fputs(buf, stderr);
1142: fclose(f);
1143: }
1.251 dtucker 1144: exit(254);
1.127 markus 1145: }
1146:
1.226 djm 1147: /*
1148: * Chroot into a directory after checking it for safety: all path components
1149: * must be root-owned directories with strict permissions.
1150: */
1151: static void
1152: safely_chroot(const char *path, uid_t uid)
1153: {
1154: const char *cp;
1.277 deraadt 1155: char component[PATH_MAX];
1.226 djm 1156: struct stat st;
1157:
1158: if (*path != '/')
1159: fatal("chroot path does not begin at root");
1160: if (strlen(path) >= sizeof(component))
1161: fatal("chroot path too long");
1162:
1163: /*
1164: * Descend the path, checking that each component is a
1165: * root-owned directory with strict permissions.
1166: */
1167: for (cp = path; cp != NULL;) {
1168: if ((cp = strchr(cp, '/')) == NULL)
1169: strlcpy(component, path, sizeof(component));
1170: else {
1171: cp++;
1172: memcpy(component, path, cp - path);
1173: component[cp - path] = '\0';
1174: }
1175:
1176: debug3("%s: checking '%s'", __func__, component);
1177:
1178: if (stat(component, &st) != 0)
1179: fatal("%s: stat(\"%s\"): %s", __func__,
1180: component, strerror(errno));
1181: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1182: fatal("bad ownership or modes for chroot "
1183: "directory %s\"%s\"",
1184: cp == NULL ? "" : "component ", component);
1185: if (!S_ISDIR(st.st_mode))
1186: fatal("chroot path %s\"%s\" is not a directory",
1187: cp == NULL ? "" : "component ", component);
1188:
1189: }
1190:
1191: if (chdir(path) == -1)
1192: fatal("Unable to chdir to chroot path \"%s\": "
1193: "%s", path, strerror(errno));
1194: if (chroot(path) == -1)
1195: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1196: if (chdir("/") == -1)
1197: fatal("%s: chdir(/) after chroot: %s",
1198: __func__, strerror(errno));
1199: verbose("Changed root directory to \"%s\"", path);
1200: }
1201:
1.127 markus 1202: /* Set login name, uid, gid, and groups. */
1.130 provos 1203: void
1.127 markus 1204: do_setusercontext(struct passwd *pw)
1205: {
1.227 djm 1206: char *chroot_path, *tmp;
1207:
1.127 markus 1208: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1209: /* Prepare groups */
1.127 markus 1210: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1211: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1212: perror("unable to set user context");
1213: exit(1);
1214: }
1.226 djm 1215:
1.279 ! djm 1216: if (!in_chroot && options.chroot_directory != NULL &&
1.226 djm 1217: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1218: tmp = tilde_expand_filename(options.chroot_directory,
1219: pw->pw_uid);
1220: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1221: "u", pw->pw_name, (char *)NULL);
1.226 djm 1222: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1223: free(tmp);
1.226 djm 1224: free(chroot_path);
1.264 djm 1225: /* Make sure we don't attempt to chroot again */
1226: free(options.chroot_directory);
1227: options.chroot_directory = NULL;
1.279 ! djm 1228: in_chroot = 1;
1.226 djm 1229: }
1230:
1231: /* Set UID */
1232: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1233: perror("unable to set user context (setuser)");
1234: exit(1);
1235: }
1.264 djm 1236: } else if (options.chroot_directory != NULL &&
1237: strcasecmp(options.chroot_directory, "none") != 0) {
1238: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1239: }
1.264 djm 1240:
1.127 markus 1241: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1242: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1243: }
1244:
1.131 markus 1245: static void
1.172 markus 1246: do_pwchange(Session *s)
1247: {
1.179 dtucker 1248: fflush(NULL);
1.172 markus 1249: fprintf(stderr, "WARNING: Your password has expired.\n");
1250: if (s->ttyfd != -1) {
1.178 deraadt 1251: fprintf(stderr,
1.172 markus 1252: "You must change your password now and login again!\n");
1253: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1254: perror("passwd");
1255: } else {
1256: fprintf(stderr,
1257: "Password change required but no TTY available.\n");
1258: }
1259: exit(1);
1260: }
1261:
1262: static void
1.130 provos 1263: launch_login(struct passwd *pw, const char *hostname)
1264: {
1265: /* Launch login(1). */
1266:
1267: execl("/usr/bin/login", "login", "-h", hostname,
1268: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1269:
1270: /* Login couldn't be executed, die. */
1271:
1272: perror("login");
1273: exit(1);
1274: }
1275:
1.172 markus 1276: static void
1277: child_close_fds(void)
1278: {
1.276 djm 1279: extern int auth_sock;
1.266 markus 1280:
1.276 djm 1281: if (auth_sock != -1) {
1282: close(auth_sock);
1283: auth_sock = -1;
1.266 markus 1284: }
1285:
1.172 markus 1286: if (packet_get_connection_in() == packet_get_connection_out())
1287: close(packet_get_connection_in());
1288: else {
1289: close(packet_get_connection_in());
1290: close(packet_get_connection_out());
1291: }
1292: /*
1293: * Close all descriptors related to channels. They will still remain
1294: * open in the parent.
1295: */
1296: /* XXX better use close-on-exec? -markus */
1297: channel_close_all();
1298:
1299: /*
1300: * Close any extra file descriptors. Note that there may still be
1301: * descriptors left by system functions. They will be closed later.
1302: */
1303: endpwent();
1304:
1305: /*
1.188 djm 1306: * Close any extra open file descriptors so that we don't have them
1.172 markus 1307: * hanging around in clients. Note that we want to do this after
1308: * initgroups, because at least on Solaris 2.3 it leaves file
1309: * descriptors open.
1310: */
1.258 djm 1311: closefrom(STDERR_FILENO + 1);
1.172 markus 1312: }
1313:
1.127 markus 1314: /*
1315: * Performs common processing for the child, such as setting up the
1316: * environment, closing extra file descriptors, setting the user and group
1317: * ids, and executing the command or shell.
1318: */
1.225 markus 1319: #define ARGV_MAX 10
1.127 markus 1320: void
1321: do_child(Session *s, const char *command)
1322: {
1323: extern char **environ;
1324: char **env;
1.225 markus 1325: char *argv[ARGV_MAX];
1.127 markus 1326: const char *shell, *shell0, *hostname = NULL;
1327: struct passwd *pw = s->pw;
1.239 djm 1328: int r = 0;
1.127 markus 1329:
1330: /* remove hostkey from the child's memory */
1331: destroy_sensitive_data();
1332:
1.172 markus 1333: /* Force a password change */
1334: if (s->authctxt->force_pwchange) {
1335: do_setusercontext(pw);
1336: child_close_fds();
1337: do_pwchange(s);
1338: exit(1);
1339: }
1340:
1.127 markus 1341: /* login(1) is only called if we execute the login shell */
1342: if (options.use_login && command != NULL)
1343: options.use_login = 0;
1344:
1345: /*
1346: * Login(1) does this as well, and it needs uid 0 for the "-h"
1347: * switch, so we let login(1) to this for us.
1348: */
1349: if (!options.use_login) {
1350: do_nologin(pw);
1351: do_setusercontext(pw);
1352: }
1353:
1354: /*
1355: * Get the shell from the password data. An empty shell field is
1356: * legal, and means /bin/sh.
1357: */
1358: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1359:
1360: /*
1361: * Make sure $SHELL points to the shell from the password file,
1362: * even if shell is overridden from login.conf
1363: */
1364: env = do_setup_env(s, shell);
1365:
1.127 markus 1366: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1367:
1.26 millert 1368: /* we have to stash the hostname before we close our socket. */
1369: if (options.use_login)
1.70 stevesk 1370: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1371: options.use_dns);
1.1 markus 1372: /*
1373: * Close the connection descriptors; note that this is the child, and
1374: * the server will still have the socket open, and it is important
1375: * that we do not shutdown it. Note that the descriptors cannot be
1376: * closed before building the environment, as we call
1377: * get_remote_ipaddr there.
1378: */
1.172 markus 1379: child_close_fds();
1.1 markus 1380:
1381: /*
1.125 deraadt 1382: * Must take new environment into use so that .ssh/rc,
1383: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1384: */
1385: environ = env;
1.170 jakob 1386:
1387: #ifdef KRB5
1388: /*
1389: * At this point, we check to see if AFS is active and if we have
1390: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1391: * if we can (and need to) extend the ticket into an AFS token. If
1392: * we don't do this, we run into potential problems if the user's
1393: * home directory is in AFS and it's not world-readable.
1394: */
1395:
1396: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1397: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1398: char cell[64];
1399:
1400: debug("Getting AFS token");
1401:
1402: k_setpag();
1403:
1404: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1405: krb5_afslog(s->authctxt->krb5_ctx,
1406: s->authctxt->krb5_fwd_ccache, cell, NULL);
1407:
1408: krb5_afslog_home(s->authctxt->krb5_ctx,
1409: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1410: }
1411: #endif
1.104 markus 1412:
1.188 djm 1413: /* Change current directory to the user's home directory. */
1.104 markus 1414: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1415: /* Suppress missing homedir warning for chroot case */
1416: r = login_getcapbool(lc, "requirehome", 0);
1.279 ! djm 1417: if (r || !in_chroot) {
1.239 djm 1418: fprintf(stderr, "Could not chdir to home "
1419: "directory %s: %s\n", pw->pw_dir,
1420: strerror(errno));
1.279 ! djm 1421: }
1.239 djm 1422: if (r)
1.104 markus 1423: exit(1);
1424: }
1.230 djm 1425:
1426: closefrom(STDERR_FILENO + 1);
1.1 markus 1427:
1.127 markus 1428: if (!options.use_login)
1429: do_rc_files(s, shell);
1.67 markus 1430:
1431: /* restore SIGPIPE for child */
1.217 stevesk 1432: signal(SIGPIPE, SIG_DFL);
1.67 markus 1433:
1.248 djm 1434: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1435: printf("This service allows sftp connections only.\n");
1436: fflush(NULL);
1437: exit(1);
1438: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1439: extern int optind, optreset;
1440: int i;
1441: char *p, *args;
1442:
1.246 stevesk 1443: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1444: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1445: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1446: if (i < ARGV_MAX - 1)
1447: argv[i++] = p;
1448: argv[i] = NULL;
1449: optind = optreset = 1;
1450: __progname = argv[0];
1.226 djm 1451: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1452: }
1.247 djm 1453:
1454: fflush(NULL);
1.225 markus 1455:
1.127 markus 1456: if (options.use_login) {
1.130 provos 1457: launch_login(pw, hostname);
1458: /* NEVERREACHED */
1.127 markus 1459: }
1460:
1461: /* Get the last component of the shell name. */
1462: if ((shell0 = strrchr(shell, '/')) != NULL)
1463: shell0++;
1464: else
1465: shell0 = shell;
1466:
1.1 markus 1467: /*
1468: * If we have no command, execute the shell. In this case, the shell
1469: * name to be passed in argv[0] is preceded by '-' to indicate that
1470: * this is a login shell.
1471: */
1472: if (!command) {
1.127 markus 1473: char argv0[256];
1.1 markus 1474:
1.127 markus 1475: /* Start the shell. Set initial character to '-'. */
1476: argv0[0] = '-';
1.1 markus 1477:
1.127 markus 1478: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1479: >= sizeof(argv0) - 1) {
1.127 markus 1480: errno = EINVAL;
1.1 markus 1481: perror(shell);
1482: exit(1);
1.127 markus 1483: }
1.1 markus 1484:
1.127 markus 1485: /* Execute the shell. */
1486: argv[0] = argv0;
1487: argv[1] = NULL;
1488: execve(shell, argv, env);
1489:
1490: /* Executing the shell failed. */
1491: perror(shell);
1492: exit(1);
1.1 markus 1493: }
1494: /*
1495: * Execute the command using the user's shell. This uses the -c
1496: * option to execute the command.
1497: */
1.127 markus 1498: argv[0] = (char *) shell0;
1.1 markus 1499: argv[1] = "-c";
1500: argv[2] = (char *) command;
1501: argv[3] = NULL;
1502: execve(shell, argv, env);
1503: perror(shell);
1504: exit(1);
1505: }
1506:
1.237 djm 1507: void
1508: session_unused(int id)
1509: {
1510: debug3("%s: session id %d unused", __func__, id);
1511: if (id >= options.max_sessions ||
1512: id >= sessions_nalloc) {
1513: fatal("%s: insane session id %d (max %d nalloc %d)",
1514: __func__, id, options.max_sessions, sessions_nalloc);
1515: }
1.270 tedu 1516: memset(&sessions[id], 0, sizeof(*sessions));
1.237 djm 1517: sessions[id].self = id;
1518: sessions[id].used = 0;
1519: sessions[id].chanid = -1;
1520: sessions[id].ptyfd = -1;
1521: sessions[id].ttyfd = -1;
1522: sessions[id].ptymaster = -1;
1523: sessions[id].x11_chanids = NULL;
1524: sessions[id].next_unused = sessions_first_unused;
1525: sessions_first_unused = id;
1526: }
1527:
1.1 markus 1528: Session *
1529: session_new(void)
1530: {
1.237 djm 1531: Session *s, *tmp;
1532:
1533: if (sessions_first_unused == -1) {
1534: if (sessions_nalloc >= options.max_sessions)
1535: return NULL;
1536: debug2("%s: allocate (allocated %d max %d)",
1537: __func__, sessions_nalloc, options.max_sessions);
1.278 deraadt 1538: tmp = xreallocarray(sessions, sessions_nalloc + 1,
1.237 djm 1539: sizeof(*sessions));
1540: if (tmp == NULL) {
1541: error("%s: cannot allocate %d sessions",
1542: __func__, sessions_nalloc + 1);
1543: return NULL;
1544: }
1545: sessions = tmp;
1546: session_unused(sessions_nalloc++);
1547: }
1548:
1549: if (sessions_first_unused >= sessions_nalloc ||
1550: sessions_first_unused < 0) {
1551: fatal("%s: insane first_unused %d max %d nalloc %d",
1552: __func__, sessions_first_unused, options.max_sessions,
1553: sessions_nalloc);
1554: }
1555:
1556: s = &sessions[sessions_first_unused];
1557: if (s->used) {
1558: fatal("%s: session %d already used",
1559: __func__, sessions_first_unused);
1560: }
1561: sessions_first_unused = s->next_unused;
1562: s->used = 1;
1563: s->next_unused = -1;
1564: debug("session_new: session %d", s->self);
1565:
1566: return s;
1.1 markus 1567: }
1568:
1.94 itojun 1569: static void
1.1 markus 1570: session_dump(void)
1571: {
1572: int i;
1.237 djm 1573: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1574: Session *s = &sessions[i];
1.237 djm 1575:
1576: debug("dump: used %d next_unused %d session %d %p "
1577: "channel %d pid %ld",
1.1 markus 1578: s->used,
1.237 djm 1579: s->next_unused,
1.1 markus 1580: s->self,
1581: s,
1582: s->chanid,
1.137 mpech 1583: (long)s->pid);
1.1 markus 1584: }
1585: }
1586:
1.2 markus 1587: int
1.97 markus 1588: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1589: {
1590: Session *s = session_new();
1591: debug("session_open: channel %d", chanid);
1592: if (s == NULL) {
1593: error("no more sessions");
1594: return 0;
1595: }
1.97 markus 1596: s->authctxt = authctxt;
1597: s->pw = authctxt->pw;
1.167 djm 1598: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1599: fatal("no user for session %d", s->self);
1.2 markus 1600: debug("session_open: session %d: link with channel %d", s->self, chanid);
1601: s->chanid = chanid;
1602: return 1;
1603: }
1604:
1.130 provos 1605: Session *
1606: session_by_tty(char *tty)
1607: {
1608: int i;
1.237 djm 1609: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1610: Session *s = &sessions[i];
1611: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1612: debug("session_by_tty: session %d tty %s", i, tty);
1613: return s;
1614: }
1615: }
1616: debug("session_by_tty: unknown tty %.100s", tty);
1617: session_dump();
1618: return NULL;
1619: }
1620:
1.94 itojun 1621: static Session *
1.2 markus 1622: session_by_channel(int id)
1623: {
1624: int i;
1.237 djm 1625: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1626: Session *s = &sessions[i];
1627: if (s->used && s->chanid == id) {
1.237 djm 1628: debug("session_by_channel: session %d channel %d",
1629: i, id);
1.2 markus 1630: return s;
1631: }
1632: }
1633: debug("session_by_channel: unknown channel %d", id);
1634: session_dump();
1635: return NULL;
1636: }
1637:
1.94 itojun 1638: static Session *
1.184 djm 1639: session_by_x11_channel(int id)
1640: {
1641: int i, j;
1642:
1.237 djm 1643: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1644: Session *s = &sessions[i];
1645:
1646: if (s->x11_chanids == NULL || !s->used)
1647: continue;
1648: for (j = 0; s->x11_chanids[j] != -1; j++) {
1649: if (s->x11_chanids[j] == id) {
1650: debug("session_by_x11_channel: session %d "
1651: "channel %d", s->self, id);
1652: return s;
1653: }
1654: }
1655: }
1656: debug("session_by_x11_channel: unknown channel %d", id);
1657: session_dump();
1658: return NULL;
1659: }
1660:
1661: static Session *
1.2 markus 1662: session_by_pid(pid_t pid)
1663: {
1664: int i;
1.137 mpech 1665: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1666: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1667: Session *s = &sessions[i];
1668: if (s->used && s->pid == pid)
1669: return s;
1670: }
1.137 mpech 1671: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1672: session_dump();
1673: return NULL;
1674: }
1675:
1.94 itojun 1676: static int
1.2 markus 1677: session_window_change_req(Session *s)
1678: {
1679: s->col = packet_get_int();
1680: s->row = packet_get_int();
1681: s->xpixel = packet_get_int();
1682: s->ypixel = packet_get_int();
1.116 markus 1683: packet_check_eom();
1.2 markus 1684: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1685: return 1;
1686: }
1687:
1.94 itojun 1688: static int
1.2 markus 1689: session_pty_req(Session *s)
1690: {
1.45 markus 1691: u_int len;
1.72 stevesk 1692: int n_bytes;
1.132 markus 1693:
1.268 djm 1694: if (no_pty_flag || !options.permit_tty) {
1.86 markus 1695: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1696: return 0;
1.86 markus 1697: }
1698: if (s->ttyfd != -1) {
1699: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1700: return 0;
1.86 markus 1701: }
1702:
1.2 markus 1703: s->term = packet_get_string(&len);
1.86 markus 1704:
1705: if (compat20) {
1706: s->col = packet_get_int();
1707: s->row = packet_get_int();
1708: } else {
1709: s->row = packet_get_int();
1710: s->col = packet_get_int();
1711: }
1.2 markus 1712: s->xpixel = packet_get_int();
1713: s->ypixel = packet_get_int();
1714:
1715: if (strcmp(s->term, "") == 0) {
1.265 djm 1716: free(s->term);
1.2 markus 1717: s->term = NULL;
1718: }
1.86 markus 1719:
1.2 markus 1720: /* Allocate a pty and open it. */
1.86 markus 1721: debug("Allocating pty.");
1.237 djm 1722: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1723: sizeof(s->tty)))) {
1.265 djm 1724: free(s->term);
1.2 markus 1725: s->term = NULL;
1726: s->ptyfd = -1;
1727: s->ttyfd = -1;
1728: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1729: return 0;
1.2 markus 1730: }
1731: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1732:
1733: /* for SSH1 the tty modes length is not given */
1734: if (!compat20)
1735: n_bytes = packet_remaining();
1736: tty_parse_modes(s->ttyfd, &n_bytes);
1737:
1.130 provos 1738: if (!use_privsep)
1739: pty_setowner(s->pw, s->tty);
1.86 markus 1740:
1741: /* Set window size from the packet. */
1.2 markus 1742: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1743:
1.116 markus 1744: packet_check_eom();
1.9 markus 1745: session_proctitle(s);
1.2 markus 1746: return 1;
1747: }
1748:
1.94 itojun 1749: static int
1.7 markus 1750: session_subsystem_req(Session *s)
1751: {
1.105 markus 1752: struct stat st;
1.45 markus 1753: u_int len;
1.7 markus 1754: int success = 0;
1.267 djm 1755: char *prog, *cmd;
1.182 djm 1756: u_int i;
1.7 markus 1757:
1.267 djm 1758: s->subsys = packet_get_string(&len);
1.116 markus 1759: packet_check_eom();
1.267 djm 1760: debug2("subsystem request for %.100s by user %s", s->subsys,
1.255 djm 1761: s->pw->pw_name);
1.18 jakob 1762:
1763: for (i = 0; i < options.num_subsystems; i++) {
1.267 djm 1764: if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1765: prog = options.subsystem_command[i];
1766: cmd = options.subsystem_args[i];
1.249 dtucker 1767: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1768: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1769: debug("subsystem: %s", prog);
1.225 markus 1770: } else {
1.249 dtucker 1771: if (stat(prog, &st) < 0)
1772: debug("subsystem: cannot stat %s: %s",
1773: prog, strerror(errno));
1.225 markus 1774: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1775: debug("subsystem: exec() %s", cmd);
1.105 markus 1776: }
1.237 djm 1777: success = do_exec(s, cmd) == 0;
1.122 markus 1778: break;
1.18 jakob 1779: }
1780: }
1781:
1782: if (!success)
1.267 djm 1783: logit("subsystem request for %.100s by user %s failed, "
1784: "subsystem not found", s->subsys, s->pw->pw_name);
1.7 markus 1785:
1786: return success;
1787: }
1788:
1.94 itojun 1789: static int
1.7 markus 1790: session_x11_req(Session *s)
1791: {
1.81 markus 1792: int success;
1.7 markus 1793:
1.184 djm 1794: if (s->auth_proto != NULL || s->auth_data != NULL) {
1795: error("session_x11_req: session %d: "
1.190 stevesk 1796: "x11 forwarding already active", s->self);
1.184 djm 1797: return 0;
1798: }
1.7 markus 1799: s->single_connection = packet_get_char();
1800: s->auth_proto = packet_get_string(NULL);
1801: s->auth_data = packet_get_string(NULL);
1802: s->screen = packet_get_int();
1.116 markus 1803: packet_check_eom();
1.7 markus 1804:
1.81 markus 1805: success = session_setup_x11fwd(s);
1806: if (!success) {
1.265 djm 1807: free(s->auth_proto);
1808: free(s->auth_data);
1.84 markus 1809: s->auth_proto = NULL;
1810: s->auth_data = NULL;
1.7 markus 1811: }
1.81 markus 1812: return success;
1.7 markus 1813: }
1814:
1.94 itojun 1815: static int
1.19 markus 1816: session_shell_req(Session *s)
1817: {
1.116 markus 1818: packet_check_eom();
1.237 djm 1819: return do_exec(s, NULL) == 0;
1.19 markus 1820: }
1821:
1.94 itojun 1822: static int
1.19 markus 1823: session_exec_req(Session *s)
1824: {
1.237 djm 1825: u_int len, success;
1826:
1.19 markus 1827: char *command = packet_get_string(&len);
1.116 markus 1828: packet_check_eom();
1.237 djm 1829: success = do_exec(s, command) == 0;
1.265 djm 1830: free(command);
1.237 djm 1831: return success;
1.19 markus 1832: }
1833:
1.94 itojun 1834: static int
1.157 markus 1835: session_break_req(Session *s)
1836: {
1837:
1.175 deraadt 1838: packet_get_int(); /* ignored */
1.157 markus 1839: packet_check_eom();
1840:
1.259 djm 1841: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1842: return 0;
1843: return 1;
1844: }
1845:
1846: static int
1.173 djm 1847: session_env_req(Session *s)
1848: {
1849: char *name, *val;
1850: u_int name_len, val_len, i;
1851:
1.271 djm 1852: name = packet_get_cstring(&name_len);
1853: val = packet_get_cstring(&val_len);
1.173 djm 1854: packet_check_eom();
1855:
1856: /* Don't set too many environment variables */
1857: if (s->num_env > 128) {
1858: debug2("Ignoring env request %s: too many env vars", name);
1859: goto fail;
1860: }
1861:
1862: for (i = 0; i < options.num_accept_env; i++) {
1863: if (match_pattern(name, options.accept_env[i])) {
1864: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.278 deraadt 1865: s->env = xreallocarray(s->env, s->num_env + 1,
1.201 djm 1866: sizeof(*s->env));
1.173 djm 1867: s->env[s->num_env].name = name;
1868: s->env[s->num_env].val = val;
1869: s->num_env++;
1870: return (1);
1871: }
1872: }
1873: debug2("Ignoring env request %s: disallowed name", name);
1874:
1875: fail:
1.265 djm 1876: free(name);
1877: free(val);
1.173 djm 1878: return (0);
1879: }
1880:
1881: static int
1.43 markus 1882: session_auth_agent_req(Session *s)
1883: {
1884: static int called = 0;
1.116 markus 1885: packet_check_eom();
1.235 pyr 1886: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1887: debug("session_auth_agent_req: no_agent_forwarding_flag");
1888: return 0;
1889: }
1.43 markus 1890: if (called) {
1891: return 0;
1892: } else {
1893: called = 1;
1894: return auth_input_request_forwarding(s->pw);
1895: }
1896: }
1897:
1.123 markus 1898: int
1899: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1900: {
1901: int success = 0;
1902: Session *s;
1903:
1.123 markus 1904: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1905: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1906: c->self, rtype);
1907: return 0;
1908: }
1909: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1910:
1911: /*
1.64 markus 1912: * a session is in LARVAL state until a shell, a command
1913: * or a subsystem is executed
1.2 markus 1914: */
1915: if (c->type == SSH_CHANNEL_LARVAL) {
1916: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1917: success = session_shell_req(s);
1.2 markus 1918: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1919: success = session_exec_req(s);
1.2 markus 1920: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1921: success = session_pty_req(s);
1.7 markus 1922: } else if (strcmp(rtype, "x11-req") == 0) {
1923: success = session_x11_req(s);
1.43 markus 1924: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1925: success = session_auth_agent_req(s);
1.7 markus 1926: } else if (strcmp(rtype, "subsystem") == 0) {
1927: success = session_subsystem_req(s);
1.173 djm 1928: } else if (strcmp(rtype, "env") == 0) {
1929: success = session_env_req(s);
1.2 markus 1930: }
1931: }
1932: if (strcmp(rtype, "window-change") == 0) {
1933: success = session_window_change_req(s);
1.177 djm 1934: } else if (strcmp(rtype, "break") == 0) {
1935: success = session_break_req(s);
1.2 markus 1936: }
1.177 djm 1937:
1.123 markus 1938: return success;
1.2 markus 1939: }
1940:
1941: void
1.256 djm 1942: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1943: int is_tty)
1.2 markus 1944: {
1945: if (!compat20)
1946: fatal("session_set_fds: called for proto != 2.0");
1947: /*
1948: * now that have a child and a pipe to the child,
1949: * we can activate our channel and register the fd's
1950: */
1951: if (s->chanid == -1)
1952: fatal("no channel for session %d", s->self);
1953: channel_set_fds(s->chanid,
1954: fdout, fdin, fderr,
1.256 djm 1955: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1956: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1957: }
1958:
1.85 markus 1959: /*
1960: * Function to perform pty cleanup. Also called if we get aborted abnormally
1961: * (e.g., due to a dropped connection).
1962: */
1.130 provos 1963: void
1.165 markus 1964: session_pty_cleanup2(Session *s)
1.1 markus 1965: {
1.85 markus 1966: if (s == NULL) {
1967: error("session_pty_cleanup: no session");
1968: return;
1969: }
1970: if (s->ttyfd == -1)
1.1 markus 1971: return;
1972:
1.54 stevesk 1973: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1974:
1975: /* Record that the user has logged out. */
1.85 markus 1976: if (s->pid != 0)
1977: record_logout(s->pid, s->tty);
1.1 markus 1978:
1979: /* Release the pseudo-tty. */
1.130 provos 1980: if (getuid() == 0)
1981: pty_release(s->tty);
1.1 markus 1982:
1983: /*
1984: * Close the server side of the socket pairs. We must do this after
1985: * the pty cleanup, so that another process doesn't get this pty
1986: * while we're still cleaning up.
1987: */
1.237 djm 1988: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
1989: error("close(s->ptymaster/%d): %s",
1990: s->ptymaster, strerror(errno));
1.108 markus 1991:
1992: /* unlink pty from session */
1993: s->ttyfd = -1;
1.2 markus 1994: }
1995:
1.130 provos 1996: void
1.165 markus 1997: session_pty_cleanup(Session *s)
1.130 provos 1998: {
1.165 markus 1999: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 2000: }
2001:
1.147 markus 2002: static char *
2003: sig2name(int sig)
2004: {
2005: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2006: SSH_SIG(ABRT);
2007: SSH_SIG(ALRM);
2008: SSH_SIG(FPE);
2009: SSH_SIG(HUP);
2010: SSH_SIG(ILL);
2011: SSH_SIG(INT);
2012: SSH_SIG(KILL);
2013: SSH_SIG(PIPE);
2014: SSH_SIG(QUIT);
2015: SSH_SIG(SEGV);
2016: SSH_SIG(TERM);
2017: SSH_SIG(USR1);
2018: SSH_SIG(USR2);
2019: #undef SSH_SIG
2020: return "SIG@openssh.com";
2021: }
2022:
1.94 itojun 2023: static void
1.184 djm 2024: session_close_x11(int id)
2025: {
2026: Channel *c;
2027:
1.189 markus 2028: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2029: debug("session_close_x11: x11 channel %d missing", id);
2030: } else {
2031: /* Detach X11 listener */
2032: debug("session_close_x11: detach x11 channel %d", id);
2033: channel_cancel_cleanup(id);
2034: if (c->ostate != CHAN_OUTPUT_CLOSED)
2035: chan_mark_dead(c);
2036: }
2037: }
2038:
2039: static void
2040: session_close_single_x11(int id, void *arg)
2041: {
2042: Session *s;
2043: u_int i;
2044:
2045: debug3("session_close_single_x11: channel %d", id);
2046: channel_cancel_cleanup(id);
1.221 stevesk 2047: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2048: fatal("session_close_single_x11: no x11 channel %d", id);
2049: for (i = 0; s->x11_chanids[i] != -1; i++) {
2050: debug("session_close_single_x11: session %d: "
2051: "closing channel %d", s->self, s->x11_chanids[i]);
2052: /*
2053: * The channel "id" is already closing, but make sure we
2054: * close all of its siblings.
2055: */
2056: if (s->x11_chanids[i] != id)
2057: session_close_x11(s->x11_chanids[i]);
2058: }
1.265 djm 2059: free(s->x11_chanids);
1.184 djm 2060: s->x11_chanids = NULL;
1.265 djm 2061: free(s->display);
2062: s->display = NULL;
2063: free(s->auth_proto);
2064: s->auth_proto = NULL;
2065: free(s->auth_data);
2066: s->auth_data = NULL;
2067: free(s->auth_display);
2068: s->auth_display = NULL;
1.184 djm 2069: }
2070:
2071: static void
1.2 markus 2072: session_exit_message(Session *s, int status)
2073: {
2074: Channel *c;
1.124 markus 2075:
2076: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2077: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2078: s->self, s->chanid);
1.137 mpech 2079: debug("session_exit_message: session %d channel %d pid %ld",
2080: s->self, s->chanid, (long)s->pid);
1.2 markus 2081:
2082: if (WIFEXITED(status)) {
1.124 markus 2083: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2084: packet_put_int(WEXITSTATUS(status));
2085: packet_send();
2086: } else if (WIFSIGNALED(status)) {
1.124 markus 2087: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2088: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2089: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2090: packet_put_cstring("");
2091: packet_put_cstring("");
2092: packet_send();
2093: } else {
2094: /* Some weird exit cause. Just exit. */
2095: packet_disconnect("wait returned status %04x.", status);
2096: }
2097:
2098: /* disconnect channel */
2099: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2100:
2101: /*
2102: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2103: * the channel gets EOF. The session will be then be closed
1.187 djm 2104: * by session_close_by_channel when the childs close their fds.
2105: */
2106: channel_register_cleanup(c->self, session_close_by_channel, 1);
2107:
1.5 markus 2108: /*
2109: * emulate a write failure with 'chan_write_failed', nobody will be
2110: * interested in data we write.
2111: * Note that we must not call 'chan_read_failed', since there could
2112: * be some more data waiting in the pipe.
2113: */
1.8 markus 2114: if (c->ostate != CHAN_OUTPUT_CLOSED)
2115: chan_write_failed(c);
1.2 markus 2116: }
2117:
1.130 provos 2118: void
1.85 markus 2119: session_close(Session *s)
1.2 markus 2120: {
1.182 djm 2121: u_int i;
1.173 djm 2122:
1.137 mpech 2123: debug("session_close: session %d pid %ld", s->self, (long)s->pid);
1.165 markus 2124: if (s->ttyfd != -1)
1.85 markus 2125: session_pty_cleanup(s);
1.265 djm 2126: free(s->term);
2127: free(s->display);
2128: free(s->x11_chanids);
2129: free(s->auth_display);
2130: free(s->auth_data);
2131: free(s->auth_proto);
1.267 djm 2132: free(s->subsys);
1.219 djm 2133: if (s->env != NULL) {
2134: for (i = 0; i < s->num_env; i++) {
1.265 djm 2135: free(s->env[i].name);
2136: free(s->env[i].val);
1.219 djm 2137: }
1.265 djm 2138: free(s->env);
1.173 djm 2139: }
1.9 markus 2140: session_proctitle(s);
1.237 djm 2141: session_unused(s->self);
1.2 markus 2142: }
2143:
2144: void
2145: session_close_by_pid(pid_t pid, int status)
2146: {
2147: Session *s = session_by_pid(pid);
2148: if (s == NULL) {
1.137 mpech 2149: debug("session_close_by_pid: no session for pid %ld",
2150: (long)pid);
1.2 markus 2151: return;
2152: }
2153: if (s->chanid != -1)
2154: session_exit_message(s, status);
1.187 djm 2155: if (s->ttyfd != -1)
2156: session_pty_cleanup(s);
1.197 djm 2157: s->pid = 0;
1.98 markus 2158: }
2159:
1.2 markus 2160: /*
2161: * this is called when a channel dies before
2162: * the session 'child' itself dies
2163: */
2164: void
2165: session_close_by_channel(int id, void *arg)
2166: {
2167: Session *s = session_by_channel(id);
1.187 djm 2168: u_int i;
1.184 djm 2169:
1.2 markus 2170: if (s == NULL) {
1.107 markus 2171: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2172: return;
2173: }
1.137 mpech 2174: debug("session_close_by_channel: channel %d child %ld",
2175: id, (long)s->pid);
1.107 markus 2176: if (s->pid != 0) {
2177: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2178: /*
2179: * delay detach of session, but release pty, since
2180: * the fd's to the child are already closed
2181: */
1.165 markus 2182: if (s->ttyfd != -1)
1.108 markus 2183: session_pty_cleanup(s);
1.107 markus 2184: return;
2185: }
2186: /* detach by removing callback */
1.2 markus 2187: channel_cancel_cleanup(s->chanid);
1.187 djm 2188:
2189: /* Close any X11 listeners associated with this session */
2190: if (s->x11_chanids != NULL) {
2191: for (i = 0; s->x11_chanids[i] != -1; i++) {
2192: session_close_x11(s->x11_chanids[i]);
2193: s->x11_chanids[i] = -1;
2194: }
2195: }
2196:
1.2 markus 2197: s->chanid = -1;
1.106 markus 2198: session_close(s);
2199: }
2200:
2201: void
1.130 provos 2202: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2203: {
2204: int i;
1.237 djm 2205: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2206: Session *s = &sessions[i];
1.130 provos 2207: if (s->used) {
2208: if (closefunc != NULL)
2209: closefunc(s);
2210: else
2211: session_close(s);
2212: }
1.2 markus 2213: }
1.9 markus 2214: }
2215:
1.94 itojun 2216: static char *
1.9 markus 2217: session_tty_list(void)
2218: {
2219: static char buf[1024];
2220: int i;
2221: buf[0] = '\0';
1.237 djm 2222: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2223: Session *s = &sessions[i];
2224: if (s->used && s->ttyfd != -1) {
2225: if (buf[0] != '\0')
2226: strlcat(buf, ",", sizeof buf);
2227: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2228: }
2229: }
2230: if (buf[0] == '\0')
2231: strlcpy(buf, "notty", sizeof buf);
2232: return buf;
2233: }
2234:
2235: void
2236: session_proctitle(Session *s)
2237: {
2238: if (s->pw == NULL)
2239: error("no user for session %d", s->self);
2240: else
2241: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2242: }
2243:
2244: int
2245: session_setup_x11fwd(Session *s)
2246: {
2247: struct stat st;
1.109 stevesk 2248: char display[512], auth_display[512];
1.272 djm 2249: char hostname[NI_MAXHOST];
1.184 djm 2250: u_int i;
1.81 markus 2251:
2252: if (no_x11_forwarding_flag) {
2253: packet_send_debug("X11 forwarding disabled in user configuration file.");
2254: return 0;
2255: }
2256: if (!options.x11_forwarding) {
2257: debug("X11 forwarding disabled in server configuration file.");
2258: return 0;
2259: }
1.275 djm 2260: if (options.xauth_location == NULL ||
1.81 markus 2261: (stat(options.xauth_location, &st) == -1)) {
2262: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2263: return 0;
2264: }
2265: if (options.use_login) {
2266: packet_send_debug("X11 forwarding disabled; "
2267: "not compatible with UseLogin=yes.");
1.81 markus 2268: return 0;
2269: }
1.87 markus 2270: if (s->display != NULL) {
1.81 markus 2271: debug("X11 display already set.");
2272: return 0;
2273: }
1.140 deraadt 2274: if (x11_create_display_inet(options.x11_display_offset,
2275: options.x11_use_localhost, s->single_connection,
1.184 djm 2276: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2277: debug("x11_create_display_inet failed.");
1.81 markus 2278: return 0;
1.184 djm 2279: }
2280: for (i = 0; s->x11_chanids[i] != -1; i++) {
2281: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2282: session_close_single_x11, 0);
1.81 markus 2283: }
1.109 stevesk 2284:
2285: /* Set up a suitable value for the DISPLAY variable. */
2286: if (gethostname(hostname, sizeof(hostname)) < 0)
2287: fatal("gethostname: %.100s", strerror(errno));
2288: /*
2289: * auth_display must be used as the displayname when the
2290: * authorization entry is added with xauth(1). This will be
2291: * different than the DISPLAY string for localhost displays.
2292: */
1.119 stevesk 2293: if (options.x11_use_localhost) {
1.140 deraadt 2294: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2295: s->display_number, s->screen);
1.140 deraadt 2296: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2297: s->display_number, s->screen);
1.109 stevesk 2298: s->display = xstrdup(display);
1.118 stevesk 2299: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2300: } else {
1.140 deraadt 2301: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2302: s->display_number, s->screen);
2303: s->display = xstrdup(display);
1.118 stevesk 2304: s->auth_display = xstrdup(display);
1.109 stevesk 2305: }
2306:
1.81 markus 2307: return 1;
1.2 markus 2308: }
2309:
1.94 itojun 2310: static void
1.49 markus 2311: do_authenticated2(Authctxt *authctxt)
1.2 markus 2312: {
1.97 markus 2313: server_loop2(authctxt);
1.165 markus 2314: }
2315:
2316: void
2317: do_cleanup(Authctxt *authctxt)
2318: {
2319: static int called = 0;
2320:
2321: debug("do_cleanup");
2322:
2323: /* no cleanup if we're in the child for login shell */
2324: if (is_child)
2325: return;
2326:
2327: /* avoid double cleanup */
2328: if (called)
2329: return;
2330: called = 1;
2331:
1.218 markus 2332: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2333: return;
2334: #ifdef KRB5
2335: if (options.kerberos_ticket_cleanup &&
2336: authctxt->krb5_ctx)
2337: krb5_cleanup_proc(authctxt);
1.161 markus 2338: #endif
1.165 markus 2339:
2340: #ifdef GSSAPI
2341: if (compat20 && options.gss_cleanup_creds)
2342: ssh_gssapi_cleanup_creds();
2343: #endif
2344:
2345: /* remove agent socket */
2346: auth_sock_cleanup_proc(authctxt->pw);
2347:
2348: /*
2349: * Cleanup ptys/utmp only if privsep is disabled,
2350: * or if running in monitor.
2351: */
2352: if (!use_privsep || mm_is_monitor())
2353: session_destroy_all(session_pty_cleanup2);
1.1 markus 2354: }
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