Annotation of src/usr.bin/ssh/session.c, Revision 1.280
1.280 ! djm 1: /* $OpenBSD: session.c,v 1.279 2015/10/24 22:52:22 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;
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;
1.280 ! djm 699: const char *forced = NULL, *tty = NULL;
! 700: char session_type[1024];
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:
1.280 ! djm 735: verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
1.267 djm 736: session_type,
737: tty == NULL ? "" : " on ",
738: tty == NULL ? "" : tty,
739: s->pw->pw_name,
740: get_remote_ipaddr(),
1.280 ! djm 741: get_remote_port(),
! 742: s->self);
1.267 djm 743:
1.163 markus 744: #ifdef GSSAPI
745: if (options.gss_authentication) {
746: temporarily_use_uid(s->pw);
747: ssh_gssapi_storecreds();
748: restore_uid();
749: }
750: #endif
1.90 markus 751: if (s->ttyfd != -1)
1.237 djm 752: ret = do_exec_pty(s, command);
1.90 markus 753: else
1.237 djm 754: ret = do_exec_no_pty(s, command);
1.90 markus 755:
1.92 markus 756: original_command = NULL;
1.179 dtucker 757:
758: /*
759: * Clear loginmsg: it's the child's responsibility to display
760: * it to the user, otherwise multiple sessions may accumulate
761: * multiple copies of the login messages.
762: */
763: buffer_clear(&loginmsg);
1.237 djm 764:
765: return ret;
1.90 markus 766: }
767:
768:
1.24 markus 769: /* administrative, login(1)-like work */
770: void
1.41 markus 771: do_login(Session *s, const char *command)
1.24 markus 772: {
773: socklen_t fromlen;
774: struct sockaddr_storage from;
775: struct passwd * pw = s->pw;
776: pid_t pid = getpid();
777:
778: /*
779: * Get IP address of client. If the connection is not a socket, let
780: * the address be 0.0.0.0.
781: */
782: memset(&from, 0, sizeof(from));
1.148 stevesk 783: fromlen = sizeof(from);
1.24 markus 784: if (packet_connection_is_on_socket()) {
785: if (getpeername(packet_get_connection_in(),
1.200 deraadt 786: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 787: debug("getpeername: %.100s", strerror(errno));
1.165 markus 788: cleanup_exit(255);
1.24 markus 789: }
790: }
1.25 markus 791:
1.24 markus 792: /* Record that there was a login on that tty from the remote host. */
1.133 markus 793: if (!use_privsep)
794: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
795: get_remote_name_or_ip(utmp_len,
1.158 markus 796: options.use_dns),
1.148 stevesk 797: (struct sockaddr *)&from, fromlen);
1.24 markus 798:
1.73 djm 799: if (check_quietlogin(s, command))
1.24 markus 800: return;
1.73 djm 801:
1.179 dtucker 802: display_loginmsg();
1.73 djm 803:
804: do_motd();
805: }
806:
807: /*
808: * Display the message of the day.
809: */
810: void
811: do_motd(void)
812: {
813: FILE *f;
814: char buf[256];
815:
1.24 markus 816: if (options.print_motd) {
1.28 millert 817: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
818: "/etc/motd"), "r");
1.24 markus 819: if (f) {
820: while (fgets(buf, sizeof(buf), f))
821: fputs(buf, stdout);
822: fclose(f);
823: }
1.2 markus 824: }
1.73 djm 825: }
826:
827:
828: /*
829: * Check for quiet login, either .hushlogin or command given.
830: */
831: int
832: check_quietlogin(Session *s, const char *command)
833: {
834: char buf[256];
1.96 dugsong 835: struct passwd *pw = s->pw;
1.73 djm 836: struct stat st;
837:
838: /* Return 1 if .hushlogin exists or a command given. */
839: if (command != NULL)
840: return 1;
841: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
842: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
843: return 1;
844: return 0;
1.1 markus 845: }
846:
847: /*
848: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 849: * already exists, its value is overridden.
1.1 markus 850: */
1.161 markus 851: void
1.45 markus 852: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 853: const char *value)
1.1 markus 854: {
1.164 markus 855: char **env;
856: u_int envsize;
1.45 markus 857: u_int i, namelen;
1.1 markus 858:
1.271 djm 859: if (strchr(name, '=') != NULL) {
860: error("Invalid environment variable \"%.100s\"", name);
861: return;
862: }
863:
1.1 markus 864: /*
865: * Find the slot where the value should be stored. If the variable
866: * already exists, we reuse the slot; otherwise we append a new slot
867: * at the end of the array, expanding if necessary.
868: */
869: env = *envp;
870: namelen = strlen(name);
871: for (i = 0; env[i]; i++)
872: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
873: break;
874: if (env[i]) {
875: /* Reuse the slot. */
1.265 djm 876: free(env[i]);
1.1 markus 877: } else {
878: /* New variable. Expand if necessary. */
1.164 markus 879: envsize = *envsizep;
880: if (i >= envsize - 1) {
881: if (envsize >= 1000)
882: fatal("child_set_env: too many env vars");
883: envsize += 50;
1.278 deraadt 884: env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1.164 markus 885: *envsizep = envsize;
1.1 markus 886: }
887: /* Need to set the NULL pointer at end of array beyond the new slot. */
888: env[i + 1] = NULL;
889: }
890:
891: /* Allocate space and format the variable in the appropriate slot. */
892: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
893: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
894: }
895:
896: /*
897: * Reads environment variables from the given file and adds/overrides them
898: * into the environment. If the file does not exist, this does nothing.
899: * Otherwise, it must consist of empty lines, comments (line starts with '#')
900: * and assignments of the form name=value. No other forms are allowed.
901: */
1.94 itojun 902: static void
1.45 markus 903: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 904: const char *filename)
1.1 markus 905: {
906: FILE *f;
907: char buf[4096];
908: char *cp, *value;
1.142 deraadt 909: u_int lineno = 0;
1.1 markus 910:
911: f = fopen(filename, "r");
912: if (!f)
913: return;
914:
915: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 916: if (++lineno > 1000)
917: fatal("Too many lines in environment file %s", filename);
1.1 markus 918: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
919: ;
920: if (!*cp || *cp == '#' || *cp == '\n')
921: continue;
1.224 gilles 922:
923: cp[strcspn(cp, "\n")] = '\0';
924:
1.1 markus 925: value = strchr(cp, '=');
926: if (value == NULL) {
1.142 deraadt 927: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
928: filename);
1.1 markus 929: continue;
930: }
1.14 deraadt 931: /*
932: * Replace the equals sign by nul, and advance value to
933: * the value string.
934: */
1.1 markus 935: *value = '\0';
936: value++;
937: child_set_env(env, envsize, cp, value);
938: }
939: fclose(f);
940: }
941:
1.127 markus 942: static char **
943: do_setup_env(Session *s, const char *shell)
1.1 markus 944: {
945: char buf[256];
1.127 markus 946: u_int i, envsize;
1.154 markus 947: char **env, *laddr;
1.127 markus 948: struct passwd *pw = s->pw;
1.1 markus 949:
950: /* Initialize the environment. */
951: envsize = 100;
1.220 djm 952: env = xcalloc(envsize, sizeof(char *));
1.1 markus 953: env[0] = NULL;
954:
1.161 markus 955: #ifdef GSSAPI
1.168 djm 956: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 957: * the childs environment as they see fit
958: */
959: ssh_gssapi_do_child(&env, &envsize);
960: #endif
961:
1.1 markus 962: if (!options.use_login) {
963: /* Set basic environment. */
1.173 djm 964: for (i = 0; i < s->num_env; i++)
1.178 deraadt 965: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 966: s->env[i].val);
967:
1.1 markus 968: child_set_env(&env, &envsize, "USER", pw->pw_name);
969: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
970: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 971: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
972: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
973: else
974: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 975:
976: snprintf(buf, sizeof buf, "%.200s/%.50s",
977: _PATH_MAILDIR, pw->pw_name);
978: child_set_env(&env, &envsize, "MAIL", buf);
979:
980: /* Normal systems set SHELL by default. */
981: child_set_env(&env, &envsize, "SHELL", shell);
982: }
983: if (getenv("TZ"))
984: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
985:
986: /* Set custom environment options from RSA authentication. */
1.110 markus 987: if (!options.use_login) {
988: while (custom_environment) {
989: struct envstring *ce = custom_environment;
1.143 deraadt 990: char *str = ce->s;
1.127 markus 991:
1.143 deraadt 992: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 993: ;
1.143 deraadt 994: if (str[i] == '=') {
995: str[i] = 0;
996: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 997: }
998: custom_environment = ce->next;
1.265 djm 999: free(ce->s);
1000: free(ce);
1.1 markus 1001: }
1002: }
1003:
1.149 stevesk 1004: /* SSH_CLIENT deprecated */
1.1 markus 1005: snprintf(buf, sizeof buf, "%.50s %d %d",
1.127 markus 1006: get_remote_ipaddr(), get_remote_port(), get_local_port());
1.1 markus 1007: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1008:
1.154 markus 1009: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1010: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.154 markus 1011: get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1.265 djm 1012: free(laddr);
1.149 stevesk 1013: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1014:
1.60 markus 1015: if (s->ttyfd != -1)
1016: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1017: if (s->term)
1018: child_set_env(&env, &envsize, "TERM", s->term);
1019: if (s->display)
1020: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1021: if (original_command)
1022: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1023: original_command);
1.96 dugsong 1024: #ifdef KRB5
1025: if (s->authctxt->krb5_ticket_file)
1026: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1027: s->authctxt->krb5_ticket_file);
1.96 dugsong 1028: #endif
1.136 markus 1029: if (auth_sock_name != NULL)
1.1 markus 1030: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1031: auth_sock_name);
1.1 markus 1032:
1033: /* read $HOME/.ssh/environment. */
1.146 markus 1034: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1035: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1036: pw->pw_dir);
1.1 markus 1037: read_environment_file(&env, &envsize, buf);
1038: }
1039: if (debug_flag) {
1040: /* dump the environment */
1041: fprintf(stderr, "Environment:\n");
1042: for (i = 0; env[i]; i++)
1043: fprintf(stderr, " %.200s\n", env[i]);
1044: }
1.127 markus 1045: return env;
1046: }
1047:
1048: /*
1049: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1050: * first in this order).
1051: */
1052: static void
1053: do_rc_files(Session *s, const char *shell)
1054: {
1055: FILE *f = NULL;
1056: char cmd[1024];
1057: int do_xauth;
1058: struct stat st;
1059:
1060: do_xauth =
1061: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1062:
1.231 djm 1063: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1064: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.273 djm 1065: !no_user_rc && options.permit_user_rc &&
1066: stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1067: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1068: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1069: if (debug_flag)
1070: fprintf(stderr, "Running %s\n", cmd);
1071: f = popen(cmd, "w");
1072: if (f) {
1073: if (do_xauth)
1074: fprintf(f, "%s %s\n", s->auth_proto,
1075: s->auth_data);
1076: pclose(f);
1077: } else
1078: fprintf(stderr, "Could not run %s\n",
1079: _PATH_SSH_USER_RC);
1080: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1081: if (debug_flag)
1082: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1083: _PATH_SSH_SYSTEM_RC);
1084: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1085: if (f) {
1086: if (do_xauth)
1087: fprintf(f, "%s %s\n", s->auth_proto,
1088: s->auth_data);
1089: pclose(f);
1090: } else
1091: fprintf(stderr, "Could not run %s\n",
1092: _PATH_SSH_SYSTEM_RC);
1093: } else if (do_xauth && options.xauth_location != NULL) {
1094: /* Add authority data to .Xauthority if appropriate. */
1095: if (debug_flag) {
1096: fprintf(stderr,
1.151 stevesk 1097: "Running %.500s remove %.100s\n",
1.165 markus 1098: options.xauth_location, s->auth_display);
1.151 stevesk 1099: fprintf(stderr,
1100: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1101: options.xauth_location, s->auth_display,
1102: s->auth_proto, s->auth_data);
1103: }
1104: snprintf(cmd, sizeof cmd, "%s -q -",
1105: options.xauth_location);
1106: f = popen(cmd, "w");
1107: if (f) {
1.151 stevesk 1108: fprintf(f, "remove %s\n",
1109: s->auth_display);
1.127 markus 1110: fprintf(f, "add %s %s %s\n",
1111: s->auth_display, s->auth_proto,
1112: s->auth_data);
1113: pclose(f);
1114: } else {
1115: fprintf(stderr, "Could not run %s\n",
1116: cmd);
1117: }
1118: }
1119: }
1120:
1121: static void
1122: do_nologin(struct passwd *pw)
1123: {
1124: FILE *f = NULL;
1.251 dtucker 1125: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1126: struct stat sb;
1.127 markus 1127:
1.260 guenther 1128: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1129: return;
1130: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1131:
1132: if (stat(nl, &sb) == -1) {
1133: if (nl != def_nl)
1.265 djm 1134: free(nl);
1.251 dtucker 1135: return;
1136: }
1137:
1138: /* /etc/nologin exists. Print its contents if we can and exit. */
1139: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1140: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1141: while (fgets(buf, sizeof(buf), f))
1142: fputs(buf, stderr);
1143: fclose(f);
1144: }
1.251 dtucker 1145: exit(254);
1.127 markus 1146: }
1147:
1.226 djm 1148: /*
1149: * Chroot into a directory after checking it for safety: all path components
1150: * must be root-owned directories with strict permissions.
1151: */
1152: static void
1153: safely_chroot(const char *path, uid_t uid)
1154: {
1155: const char *cp;
1.277 deraadt 1156: char component[PATH_MAX];
1.226 djm 1157: struct stat st;
1158:
1159: if (*path != '/')
1160: fatal("chroot path does not begin at root");
1161: if (strlen(path) >= sizeof(component))
1162: fatal("chroot path too long");
1163:
1164: /*
1165: * Descend the path, checking that each component is a
1166: * root-owned directory with strict permissions.
1167: */
1168: for (cp = path; cp != NULL;) {
1169: if ((cp = strchr(cp, '/')) == NULL)
1170: strlcpy(component, path, sizeof(component));
1171: else {
1172: cp++;
1173: memcpy(component, path, cp - path);
1174: component[cp - path] = '\0';
1175: }
1176:
1177: debug3("%s: checking '%s'", __func__, component);
1178:
1179: if (stat(component, &st) != 0)
1180: fatal("%s: stat(\"%s\"): %s", __func__,
1181: component, strerror(errno));
1182: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1183: fatal("bad ownership or modes for chroot "
1184: "directory %s\"%s\"",
1185: cp == NULL ? "" : "component ", component);
1186: if (!S_ISDIR(st.st_mode))
1187: fatal("chroot path %s\"%s\" is not a directory",
1188: cp == NULL ? "" : "component ", component);
1189:
1190: }
1191:
1192: if (chdir(path) == -1)
1193: fatal("Unable to chdir to chroot path \"%s\": "
1194: "%s", path, strerror(errno));
1195: if (chroot(path) == -1)
1196: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1197: if (chdir("/") == -1)
1198: fatal("%s: chdir(/) after chroot: %s",
1199: __func__, strerror(errno));
1200: verbose("Changed root directory to \"%s\"", path);
1201: }
1202:
1.127 markus 1203: /* Set login name, uid, gid, and groups. */
1.130 provos 1204: void
1.127 markus 1205: do_setusercontext(struct passwd *pw)
1206: {
1.227 djm 1207: char *chroot_path, *tmp;
1208:
1.127 markus 1209: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1210: /* Prepare groups */
1.127 markus 1211: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1212: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1213: perror("unable to set user context");
1214: exit(1);
1215: }
1.226 djm 1216:
1.279 djm 1217: if (!in_chroot && options.chroot_directory != NULL &&
1.226 djm 1218: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1219: tmp = tilde_expand_filename(options.chroot_directory,
1220: pw->pw_uid);
1221: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1222: "u", pw->pw_name, (char *)NULL);
1.226 djm 1223: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1224: free(tmp);
1.226 djm 1225: free(chroot_path);
1.264 djm 1226: /* Make sure we don't attempt to chroot again */
1227: free(options.chroot_directory);
1228: options.chroot_directory = NULL;
1.279 djm 1229: in_chroot = 1;
1.226 djm 1230: }
1231:
1232: /* Set UID */
1233: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1234: perror("unable to set user context (setuser)");
1235: exit(1);
1236: }
1.264 djm 1237: } else if (options.chroot_directory != NULL &&
1238: strcasecmp(options.chroot_directory, "none") != 0) {
1239: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1240: }
1.264 djm 1241:
1.127 markus 1242: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1243: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1244: }
1245:
1.131 markus 1246: static void
1.172 markus 1247: do_pwchange(Session *s)
1248: {
1.179 dtucker 1249: fflush(NULL);
1.172 markus 1250: fprintf(stderr, "WARNING: Your password has expired.\n");
1251: if (s->ttyfd != -1) {
1.178 deraadt 1252: fprintf(stderr,
1.172 markus 1253: "You must change your password now and login again!\n");
1254: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1255: perror("passwd");
1256: } else {
1257: fprintf(stderr,
1258: "Password change required but no TTY available.\n");
1259: }
1260: exit(1);
1261: }
1262:
1263: static void
1.130 provos 1264: launch_login(struct passwd *pw, const char *hostname)
1265: {
1266: /* Launch login(1). */
1267:
1268: execl("/usr/bin/login", "login", "-h", hostname,
1269: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1270:
1271: /* Login couldn't be executed, die. */
1272:
1273: perror("login");
1274: exit(1);
1275: }
1276:
1.172 markus 1277: static void
1278: child_close_fds(void)
1279: {
1.276 djm 1280: extern int auth_sock;
1.266 markus 1281:
1.276 djm 1282: if (auth_sock != -1) {
1283: close(auth_sock);
1284: auth_sock = -1;
1.266 markus 1285: }
1286:
1.172 markus 1287: if (packet_get_connection_in() == packet_get_connection_out())
1288: close(packet_get_connection_in());
1289: else {
1290: close(packet_get_connection_in());
1291: close(packet_get_connection_out());
1292: }
1293: /*
1294: * Close all descriptors related to channels. They will still remain
1295: * open in the parent.
1296: */
1297: /* XXX better use close-on-exec? -markus */
1298: channel_close_all();
1299:
1300: /*
1301: * Close any extra file descriptors. Note that there may still be
1302: * descriptors left by system functions. They will be closed later.
1303: */
1304: endpwent();
1305:
1306: /*
1.188 djm 1307: * Close any extra open file descriptors so that we don't have them
1.172 markus 1308: * hanging around in clients. Note that we want to do this after
1309: * initgroups, because at least on Solaris 2.3 it leaves file
1310: * descriptors open.
1311: */
1.258 djm 1312: closefrom(STDERR_FILENO + 1);
1.172 markus 1313: }
1314:
1.127 markus 1315: /*
1316: * Performs common processing for the child, such as setting up the
1317: * environment, closing extra file descriptors, setting the user and group
1318: * ids, and executing the command or shell.
1319: */
1.225 markus 1320: #define ARGV_MAX 10
1.127 markus 1321: void
1322: do_child(Session *s, const char *command)
1323: {
1324: extern char **environ;
1325: char **env;
1.225 markus 1326: char *argv[ARGV_MAX];
1.127 markus 1327: const char *shell, *shell0, *hostname = NULL;
1328: struct passwd *pw = s->pw;
1.239 djm 1329: int r = 0;
1.127 markus 1330:
1331: /* remove hostkey from the child's memory */
1332: destroy_sensitive_data();
1333:
1.172 markus 1334: /* Force a password change */
1335: if (s->authctxt->force_pwchange) {
1336: do_setusercontext(pw);
1337: child_close_fds();
1338: do_pwchange(s);
1339: exit(1);
1340: }
1341:
1.127 markus 1342: /* login(1) is only called if we execute the login shell */
1343: if (options.use_login && command != NULL)
1344: options.use_login = 0;
1345:
1346: /*
1347: * Login(1) does this as well, and it needs uid 0 for the "-h"
1348: * switch, so we let login(1) to this for us.
1349: */
1350: if (!options.use_login) {
1351: do_nologin(pw);
1352: do_setusercontext(pw);
1353: }
1354:
1355: /*
1356: * Get the shell from the password data. An empty shell field is
1357: * legal, and means /bin/sh.
1358: */
1359: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1360:
1361: /*
1362: * Make sure $SHELL points to the shell from the password file,
1363: * even if shell is overridden from login.conf
1364: */
1365: env = do_setup_env(s, shell);
1366:
1.127 markus 1367: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1368:
1.26 millert 1369: /* we have to stash the hostname before we close our socket. */
1370: if (options.use_login)
1.70 stevesk 1371: hostname = get_remote_name_or_ip(utmp_len,
1.158 markus 1372: options.use_dns);
1.1 markus 1373: /*
1374: * Close the connection descriptors; note that this is the child, and
1375: * the server will still have the socket open, and it is important
1376: * that we do not shutdown it. Note that the descriptors cannot be
1377: * closed before building the environment, as we call
1378: * get_remote_ipaddr there.
1379: */
1.172 markus 1380: child_close_fds();
1.1 markus 1381:
1382: /*
1.125 deraadt 1383: * Must take new environment into use so that .ssh/rc,
1384: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1385: */
1386: environ = env;
1.170 jakob 1387:
1388: #ifdef KRB5
1389: /*
1390: * At this point, we check to see if AFS is active and if we have
1391: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1392: * if we can (and need to) extend the ticket into an AFS token. If
1393: * we don't do this, we run into potential problems if the user's
1394: * home directory is in AFS and it's not world-readable.
1395: */
1396:
1397: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1398: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1399: char cell[64];
1400:
1401: debug("Getting AFS token");
1402:
1403: k_setpag();
1404:
1405: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1406: krb5_afslog(s->authctxt->krb5_ctx,
1407: s->authctxt->krb5_fwd_ccache, cell, NULL);
1408:
1409: krb5_afslog_home(s->authctxt->krb5_ctx,
1410: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1411: }
1412: #endif
1.104 markus 1413:
1.188 djm 1414: /* Change current directory to the user's home directory. */
1.104 markus 1415: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1416: /* Suppress missing homedir warning for chroot case */
1417: r = login_getcapbool(lc, "requirehome", 0);
1.279 djm 1418: if (r || !in_chroot) {
1.239 djm 1419: fprintf(stderr, "Could not chdir to home "
1420: "directory %s: %s\n", pw->pw_dir,
1421: strerror(errno));
1.279 djm 1422: }
1.239 djm 1423: if (r)
1.104 markus 1424: exit(1);
1425: }
1.230 djm 1426:
1427: closefrom(STDERR_FILENO + 1);
1.1 markus 1428:
1.127 markus 1429: if (!options.use_login)
1430: do_rc_files(s, shell);
1.67 markus 1431:
1432: /* restore SIGPIPE for child */
1.217 stevesk 1433: signal(SIGPIPE, SIG_DFL);
1.67 markus 1434:
1.248 djm 1435: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1436: printf("This service allows sftp connections only.\n");
1437: fflush(NULL);
1438: exit(1);
1439: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1440: extern int optind, optreset;
1441: int i;
1442: char *p, *args;
1443:
1.246 stevesk 1444: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1445: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1446: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1447: if (i < ARGV_MAX - 1)
1448: argv[i++] = p;
1449: argv[i] = NULL;
1450: optind = optreset = 1;
1451: __progname = argv[0];
1.226 djm 1452: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1453: }
1.247 djm 1454:
1455: fflush(NULL);
1.225 markus 1456:
1.127 markus 1457: if (options.use_login) {
1.130 provos 1458: launch_login(pw, hostname);
1459: /* NEVERREACHED */
1.127 markus 1460: }
1461:
1462: /* Get the last component of the shell name. */
1463: if ((shell0 = strrchr(shell, '/')) != NULL)
1464: shell0++;
1465: else
1466: shell0 = shell;
1467:
1.1 markus 1468: /*
1469: * If we have no command, execute the shell. In this case, the shell
1470: * name to be passed in argv[0] is preceded by '-' to indicate that
1471: * this is a login shell.
1472: */
1473: if (!command) {
1.127 markus 1474: char argv0[256];
1.1 markus 1475:
1.127 markus 1476: /* Start the shell. Set initial character to '-'. */
1477: argv0[0] = '-';
1.1 markus 1478:
1.127 markus 1479: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1480: >= sizeof(argv0) - 1) {
1.127 markus 1481: errno = EINVAL;
1.1 markus 1482: perror(shell);
1483: exit(1);
1.127 markus 1484: }
1.1 markus 1485:
1.127 markus 1486: /* Execute the shell. */
1487: argv[0] = argv0;
1488: argv[1] = NULL;
1489: execve(shell, argv, env);
1490:
1491: /* Executing the shell failed. */
1492: perror(shell);
1493: exit(1);
1.1 markus 1494: }
1495: /*
1496: * Execute the command using the user's shell. This uses the -c
1497: * option to execute the command.
1498: */
1.127 markus 1499: argv[0] = (char *) shell0;
1.1 markus 1500: argv[1] = "-c";
1501: argv[2] = (char *) command;
1502: argv[3] = NULL;
1503: execve(shell, argv, env);
1504: perror(shell);
1505: exit(1);
1506: }
1507:
1.237 djm 1508: void
1509: session_unused(int id)
1510: {
1511: debug3("%s: session id %d unused", __func__, id);
1512: if (id >= options.max_sessions ||
1513: id >= sessions_nalloc) {
1514: fatal("%s: insane session id %d (max %d nalloc %d)",
1515: __func__, id, options.max_sessions, sessions_nalloc);
1516: }
1.270 tedu 1517: memset(&sessions[id], 0, sizeof(*sessions));
1.237 djm 1518: sessions[id].self = id;
1519: sessions[id].used = 0;
1520: sessions[id].chanid = -1;
1521: sessions[id].ptyfd = -1;
1522: sessions[id].ttyfd = -1;
1523: sessions[id].ptymaster = -1;
1524: sessions[id].x11_chanids = NULL;
1525: sessions[id].next_unused = sessions_first_unused;
1526: sessions_first_unused = id;
1527: }
1528:
1.1 markus 1529: Session *
1530: session_new(void)
1531: {
1.237 djm 1532: Session *s, *tmp;
1533:
1534: if (sessions_first_unused == -1) {
1535: if (sessions_nalloc >= options.max_sessions)
1536: return NULL;
1537: debug2("%s: allocate (allocated %d max %d)",
1538: __func__, sessions_nalloc, options.max_sessions);
1.278 deraadt 1539: tmp = xreallocarray(sessions, sessions_nalloc + 1,
1.237 djm 1540: sizeof(*sessions));
1541: if (tmp == NULL) {
1542: error("%s: cannot allocate %d sessions",
1543: __func__, sessions_nalloc + 1);
1544: return NULL;
1545: }
1546: sessions = tmp;
1547: session_unused(sessions_nalloc++);
1548: }
1549:
1550: if (sessions_first_unused >= sessions_nalloc ||
1551: sessions_first_unused < 0) {
1552: fatal("%s: insane first_unused %d max %d nalloc %d",
1553: __func__, sessions_first_unused, options.max_sessions,
1554: sessions_nalloc);
1555: }
1556:
1557: s = &sessions[sessions_first_unused];
1558: if (s->used) {
1559: fatal("%s: session %d already used",
1560: __func__, sessions_first_unused);
1561: }
1562: sessions_first_unused = s->next_unused;
1563: s->used = 1;
1564: s->next_unused = -1;
1565: debug("session_new: session %d", s->self);
1566:
1567: return s;
1.1 markus 1568: }
1569:
1.94 itojun 1570: static void
1.1 markus 1571: session_dump(void)
1572: {
1573: int i;
1.237 djm 1574: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1575: Session *s = &sessions[i];
1.237 djm 1576:
1577: debug("dump: used %d next_unused %d session %d %p "
1578: "channel %d pid %ld",
1.1 markus 1579: s->used,
1.237 djm 1580: s->next_unused,
1.1 markus 1581: s->self,
1582: s,
1583: s->chanid,
1.137 mpech 1584: (long)s->pid);
1.1 markus 1585: }
1586: }
1587:
1.2 markus 1588: int
1.97 markus 1589: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1590: {
1591: Session *s = session_new();
1592: debug("session_open: channel %d", chanid);
1593: if (s == NULL) {
1594: error("no more sessions");
1595: return 0;
1596: }
1.97 markus 1597: s->authctxt = authctxt;
1598: s->pw = authctxt->pw;
1.167 djm 1599: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1600: fatal("no user for session %d", s->self);
1.2 markus 1601: debug("session_open: session %d: link with channel %d", s->self, chanid);
1602: s->chanid = chanid;
1603: return 1;
1604: }
1605:
1.130 provos 1606: Session *
1607: session_by_tty(char *tty)
1608: {
1609: int i;
1.237 djm 1610: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1611: Session *s = &sessions[i];
1612: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1613: debug("session_by_tty: session %d tty %s", i, tty);
1614: return s;
1615: }
1616: }
1617: debug("session_by_tty: unknown tty %.100s", tty);
1618: session_dump();
1619: return NULL;
1620: }
1621:
1.94 itojun 1622: static Session *
1.2 markus 1623: session_by_channel(int id)
1624: {
1625: int i;
1.237 djm 1626: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1627: Session *s = &sessions[i];
1628: if (s->used && s->chanid == id) {
1.237 djm 1629: debug("session_by_channel: session %d channel %d",
1630: i, id);
1.2 markus 1631: return s;
1632: }
1633: }
1634: debug("session_by_channel: unknown channel %d", id);
1635: session_dump();
1636: return NULL;
1637: }
1638:
1.94 itojun 1639: static Session *
1.184 djm 1640: session_by_x11_channel(int id)
1641: {
1642: int i, j;
1643:
1.237 djm 1644: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1645: Session *s = &sessions[i];
1646:
1647: if (s->x11_chanids == NULL || !s->used)
1648: continue;
1649: for (j = 0; s->x11_chanids[j] != -1; j++) {
1650: if (s->x11_chanids[j] == id) {
1651: debug("session_by_x11_channel: session %d "
1652: "channel %d", s->self, id);
1653: return s;
1654: }
1655: }
1656: }
1657: debug("session_by_x11_channel: unknown channel %d", id);
1658: session_dump();
1659: return NULL;
1660: }
1661:
1662: static Session *
1.2 markus 1663: session_by_pid(pid_t pid)
1664: {
1665: int i;
1.137 mpech 1666: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1667: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1668: Session *s = &sessions[i];
1669: if (s->used && s->pid == pid)
1670: return s;
1671: }
1.137 mpech 1672: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1673: session_dump();
1674: return NULL;
1675: }
1676:
1.94 itojun 1677: static int
1.2 markus 1678: session_window_change_req(Session *s)
1679: {
1680: s->col = packet_get_int();
1681: s->row = packet_get_int();
1682: s->xpixel = packet_get_int();
1683: s->ypixel = packet_get_int();
1.116 markus 1684: packet_check_eom();
1.2 markus 1685: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1686: return 1;
1687: }
1688:
1.94 itojun 1689: static int
1.2 markus 1690: session_pty_req(Session *s)
1691: {
1.45 markus 1692: u_int len;
1.72 stevesk 1693: int n_bytes;
1.132 markus 1694:
1.268 djm 1695: if (no_pty_flag || !options.permit_tty) {
1.86 markus 1696: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1697: return 0;
1.86 markus 1698: }
1699: if (s->ttyfd != -1) {
1700: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1701: return 0;
1.86 markus 1702: }
1703:
1.2 markus 1704: s->term = packet_get_string(&len);
1.86 markus 1705:
1706: if (compat20) {
1707: s->col = packet_get_int();
1708: s->row = packet_get_int();
1709: } else {
1710: s->row = packet_get_int();
1711: s->col = packet_get_int();
1712: }
1.2 markus 1713: s->xpixel = packet_get_int();
1714: s->ypixel = packet_get_int();
1715:
1716: if (strcmp(s->term, "") == 0) {
1.265 djm 1717: free(s->term);
1.2 markus 1718: s->term = NULL;
1719: }
1.86 markus 1720:
1.2 markus 1721: /* Allocate a pty and open it. */
1.86 markus 1722: debug("Allocating pty.");
1.237 djm 1723: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1724: sizeof(s->tty)))) {
1.265 djm 1725: free(s->term);
1.2 markus 1726: s->term = NULL;
1727: s->ptyfd = -1;
1728: s->ttyfd = -1;
1729: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1730: return 0;
1.2 markus 1731: }
1732: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1733:
1734: /* for SSH1 the tty modes length is not given */
1735: if (!compat20)
1736: n_bytes = packet_remaining();
1737: tty_parse_modes(s->ttyfd, &n_bytes);
1738:
1.130 provos 1739: if (!use_privsep)
1740: pty_setowner(s->pw, s->tty);
1.86 markus 1741:
1742: /* Set window size from the packet. */
1.2 markus 1743: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1744:
1.116 markus 1745: packet_check_eom();
1.9 markus 1746: session_proctitle(s);
1.2 markus 1747: return 1;
1748: }
1749:
1.94 itojun 1750: static int
1.7 markus 1751: session_subsystem_req(Session *s)
1752: {
1.105 markus 1753: struct stat st;
1.45 markus 1754: u_int len;
1.7 markus 1755: int success = 0;
1.267 djm 1756: char *prog, *cmd;
1.182 djm 1757: u_int i;
1.7 markus 1758:
1.267 djm 1759: s->subsys = packet_get_string(&len);
1.116 markus 1760: packet_check_eom();
1.267 djm 1761: debug2("subsystem request for %.100s by user %s", s->subsys,
1.255 djm 1762: s->pw->pw_name);
1.18 jakob 1763:
1764: for (i = 0; i < options.num_subsystems; i++) {
1.267 djm 1765: if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1766: prog = options.subsystem_command[i];
1767: cmd = options.subsystem_args[i];
1.249 dtucker 1768: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1769: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1770: debug("subsystem: %s", prog);
1.225 markus 1771: } else {
1.249 dtucker 1772: if (stat(prog, &st) < 0)
1773: debug("subsystem: cannot stat %s: %s",
1774: prog, strerror(errno));
1.225 markus 1775: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1776: debug("subsystem: exec() %s", cmd);
1.105 markus 1777: }
1.237 djm 1778: success = do_exec(s, cmd) == 0;
1.122 markus 1779: break;
1.18 jakob 1780: }
1781: }
1782:
1783: if (!success)
1.267 djm 1784: logit("subsystem request for %.100s by user %s failed, "
1785: "subsystem not found", s->subsys, s->pw->pw_name);
1.7 markus 1786:
1787: return success;
1788: }
1789:
1.94 itojun 1790: static int
1.7 markus 1791: session_x11_req(Session *s)
1792: {
1.81 markus 1793: int success;
1.7 markus 1794:
1.184 djm 1795: if (s->auth_proto != NULL || s->auth_data != NULL) {
1796: error("session_x11_req: session %d: "
1.190 stevesk 1797: "x11 forwarding already active", s->self);
1.184 djm 1798: return 0;
1799: }
1.7 markus 1800: s->single_connection = packet_get_char();
1801: s->auth_proto = packet_get_string(NULL);
1802: s->auth_data = packet_get_string(NULL);
1803: s->screen = packet_get_int();
1.116 markus 1804: packet_check_eom();
1.7 markus 1805:
1.81 markus 1806: success = session_setup_x11fwd(s);
1807: if (!success) {
1.265 djm 1808: free(s->auth_proto);
1809: free(s->auth_data);
1.84 markus 1810: s->auth_proto = NULL;
1811: s->auth_data = NULL;
1.7 markus 1812: }
1.81 markus 1813: return success;
1.7 markus 1814: }
1815:
1.94 itojun 1816: static int
1.19 markus 1817: session_shell_req(Session *s)
1818: {
1.116 markus 1819: packet_check_eom();
1.237 djm 1820: return do_exec(s, NULL) == 0;
1.19 markus 1821: }
1822:
1.94 itojun 1823: static int
1.19 markus 1824: session_exec_req(Session *s)
1825: {
1.237 djm 1826: u_int len, success;
1827:
1.19 markus 1828: char *command = packet_get_string(&len);
1.116 markus 1829: packet_check_eom();
1.237 djm 1830: success = do_exec(s, command) == 0;
1.265 djm 1831: free(command);
1.237 djm 1832: return success;
1.19 markus 1833: }
1834:
1.94 itojun 1835: static int
1.157 markus 1836: session_break_req(Session *s)
1837: {
1838:
1.175 deraadt 1839: packet_get_int(); /* ignored */
1.157 markus 1840: packet_check_eom();
1841:
1.259 djm 1842: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1843: return 0;
1844: return 1;
1845: }
1846:
1847: static int
1.173 djm 1848: session_env_req(Session *s)
1849: {
1850: char *name, *val;
1851: u_int name_len, val_len, i;
1852:
1.271 djm 1853: name = packet_get_cstring(&name_len);
1854: val = packet_get_cstring(&val_len);
1.173 djm 1855: packet_check_eom();
1856:
1857: /* Don't set too many environment variables */
1858: if (s->num_env > 128) {
1859: debug2("Ignoring env request %s: too many env vars", name);
1860: goto fail;
1861: }
1862:
1863: for (i = 0; i < options.num_accept_env; i++) {
1864: if (match_pattern(name, options.accept_env[i])) {
1865: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.278 deraadt 1866: s->env = xreallocarray(s->env, s->num_env + 1,
1.201 djm 1867: sizeof(*s->env));
1.173 djm 1868: s->env[s->num_env].name = name;
1869: s->env[s->num_env].val = val;
1870: s->num_env++;
1871: return (1);
1872: }
1873: }
1874: debug2("Ignoring env request %s: disallowed name", name);
1875:
1876: fail:
1.265 djm 1877: free(name);
1878: free(val);
1.173 djm 1879: return (0);
1880: }
1881:
1882: static int
1.43 markus 1883: session_auth_agent_req(Session *s)
1884: {
1885: static int called = 0;
1.116 markus 1886: packet_check_eom();
1.235 pyr 1887: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1888: debug("session_auth_agent_req: no_agent_forwarding_flag");
1889: return 0;
1890: }
1.43 markus 1891: if (called) {
1892: return 0;
1893: } else {
1894: called = 1;
1895: return auth_input_request_forwarding(s->pw);
1896: }
1897: }
1898:
1.123 markus 1899: int
1900: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1901: {
1902: int success = 0;
1903: Session *s;
1904:
1.123 markus 1905: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1906: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1907: c->self, rtype);
1908: return 0;
1909: }
1910: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1911:
1912: /*
1.64 markus 1913: * a session is in LARVAL state until a shell, a command
1914: * or a subsystem is executed
1.2 markus 1915: */
1916: if (c->type == SSH_CHANNEL_LARVAL) {
1917: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1918: success = session_shell_req(s);
1.2 markus 1919: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1920: success = session_exec_req(s);
1.2 markus 1921: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1922: success = session_pty_req(s);
1.7 markus 1923: } else if (strcmp(rtype, "x11-req") == 0) {
1924: success = session_x11_req(s);
1.43 markus 1925: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1926: success = session_auth_agent_req(s);
1.7 markus 1927: } else if (strcmp(rtype, "subsystem") == 0) {
1928: success = session_subsystem_req(s);
1.173 djm 1929: } else if (strcmp(rtype, "env") == 0) {
1930: success = session_env_req(s);
1.2 markus 1931: }
1932: }
1933: if (strcmp(rtype, "window-change") == 0) {
1934: success = session_window_change_req(s);
1.177 djm 1935: } else if (strcmp(rtype, "break") == 0) {
1936: success = session_break_req(s);
1.2 markus 1937: }
1.177 djm 1938:
1.123 markus 1939: return success;
1.2 markus 1940: }
1941:
1942: void
1.256 djm 1943: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1944: int is_tty)
1.2 markus 1945: {
1946: if (!compat20)
1947: fatal("session_set_fds: called for proto != 2.0");
1948: /*
1949: * now that have a child and a pipe to the child,
1950: * we can activate our channel and register the fd's
1951: */
1952: if (s->chanid == -1)
1953: fatal("no channel for session %d", s->self);
1954: channel_set_fds(s->chanid,
1955: fdout, fdin, fderr,
1.256 djm 1956: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1957: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1958: }
1959:
1.85 markus 1960: /*
1961: * Function to perform pty cleanup. Also called if we get aborted abnormally
1962: * (e.g., due to a dropped connection).
1963: */
1.130 provos 1964: void
1.165 markus 1965: session_pty_cleanup2(Session *s)
1.1 markus 1966: {
1.85 markus 1967: if (s == NULL) {
1968: error("session_pty_cleanup: no session");
1969: return;
1970: }
1971: if (s->ttyfd == -1)
1.1 markus 1972: return;
1973:
1.54 stevesk 1974: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1975:
1976: /* Record that the user has logged out. */
1.85 markus 1977: if (s->pid != 0)
1978: record_logout(s->pid, s->tty);
1.1 markus 1979:
1980: /* Release the pseudo-tty. */
1.130 provos 1981: if (getuid() == 0)
1982: pty_release(s->tty);
1.1 markus 1983:
1984: /*
1985: * Close the server side of the socket pairs. We must do this after
1986: * the pty cleanup, so that another process doesn't get this pty
1987: * while we're still cleaning up.
1988: */
1.237 djm 1989: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
1990: error("close(s->ptymaster/%d): %s",
1991: s->ptymaster, strerror(errno));
1.108 markus 1992:
1993: /* unlink pty from session */
1994: s->ttyfd = -1;
1.2 markus 1995: }
1996:
1.130 provos 1997: void
1.165 markus 1998: session_pty_cleanup(Session *s)
1.130 provos 1999: {
1.165 markus 2000: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 2001: }
2002:
1.147 markus 2003: static char *
2004: sig2name(int sig)
2005: {
2006: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2007: SSH_SIG(ABRT);
2008: SSH_SIG(ALRM);
2009: SSH_SIG(FPE);
2010: SSH_SIG(HUP);
2011: SSH_SIG(ILL);
2012: SSH_SIG(INT);
2013: SSH_SIG(KILL);
2014: SSH_SIG(PIPE);
2015: SSH_SIG(QUIT);
2016: SSH_SIG(SEGV);
2017: SSH_SIG(TERM);
2018: SSH_SIG(USR1);
2019: SSH_SIG(USR2);
2020: #undef SSH_SIG
2021: return "SIG@openssh.com";
2022: }
2023:
1.94 itojun 2024: static void
1.184 djm 2025: session_close_x11(int id)
2026: {
2027: Channel *c;
2028:
1.189 markus 2029: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2030: debug("session_close_x11: x11 channel %d missing", id);
2031: } else {
2032: /* Detach X11 listener */
2033: debug("session_close_x11: detach x11 channel %d", id);
2034: channel_cancel_cleanup(id);
2035: if (c->ostate != CHAN_OUTPUT_CLOSED)
2036: chan_mark_dead(c);
2037: }
2038: }
2039:
2040: static void
2041: session_close_single_x11(int id, void *arg)
2042: {
2043: Session *s;
2044: u_int i;
2045:
2046: debug3("session_close_single_x11: channel %d", id);
2047: channel_cancel_cleanup(id);
1.221 stevesk 2048: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2049: fatal("session_close_single_x11: no x11 channel %d", id);
2050: for (i = 0; s->x11_chanids[i] != -1; i++) {
2051: debug("session_close_single_x11: session %d: "
2052: "closing channel %d", s->self, s->x11_chanids[i]);
2053: /*
2054: * The channel "id" is already closing, but make sure we
2055: * close all of its siblings.
2056: */
2057: if (s->x11_chanids[i] != id)
2058: session_close_x11(s->x11_chanids[i]);
2059: }
1.265 djm 2060: free(s->x11_chanids);
1.184 djm 2061: s->x11_chanids = NULL;
1.265 djm 2062: free(s->display);
2063: s->display = NULL;
2064: free(s->auth_proto);
2065: s->auth_proto = NULL;
2066: free(s->auth_data);
2067: s->auth_data = NULL;
2068: free(s->auth_display);
2069: s->auth_display = NULL;
1.184 djm 2070: }
2071:
2072: static void
1.2 markus 2073: session_exit_message(Session *s, int status)
2074: {
2075: Channel *c;
1.124 markus 2076:
2077: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2078: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2079: s->self, s->chanid);
1.137 mpech 2080: debug("session_exit_message: session %d channel %d pid %ld",
2081: s->self, s->chanid, (long)s->pid);
1.2 markus 2082:
2083: if (WIFEXITED(status)) {
1.124 markus 2084: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2085: packet_put_int(WEXITSTATUS(status));
2086: packet_send();
2087: } else if (WIFSIGNALED(status)) {
1.124 markus 2088: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2089: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2090: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2091: packet_put_cstring("");
2092: packet_put_cstring("");
2093: packet_send();
2094: } else {
2095: /* Some weird exit cause. Just exit. */
2096: packet_disconnect("wait returned status %04x.", status);
2097: }
2098:
2099: /* disconnect channel */
2100: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2101:
2102: /*
2103: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2104: * the channel gets EOF. The session will be then be closed
1.187 djm 2105: * by session_close_by_channel when the childs close their fds.
2106: */
2107: channel_register_cleanup(c->self, session_close_by_channel, 1);
2108:
1.5 markus 2109: /*
2110: * emulate a write failure with 'chan_write_failed', nobody will be
2111: * interested in data we write.
2112: * Note that we must not call 'chan_read_failed', since there could
2113: * be some more data waiting in the pipe.
2114: */
1.8 markus 2115: if (c->ostate != CHAN_OUTPUT_CLOSED)
2116: chan_write_failed(c);
1.2 markus 2117: }
2118:
1.130 provos 2119: void
1.85 markus 2120: session_close(Session *s)
1.2 markus 2121: {
1.182 djm 2122: u_int i;
1.173 djm 2123:
1.280 ! djm 2124: verbose("Close session: user %s from %.200s port %d id %d",
! 2125: s->pw->pw_name,
! 2126: get_remote_ipaddr(),
! 2127: get_remote_port(),
! 2128: s->self);
! 2129:
1.165 markus 2130: if (s->ttyfd != -1)
1.85 markus 2131: session_pty_cleanup(s);
1.265 djm 2132: free(s->term);
2133: free(s->display);
2134: free(s->x11_chanids);
2135: free(s->auth_display);
2136: free(s->auth_data);
2137: free(s->auth_proto);
1.267 djm 2138: free(s->subsys);
1.219 djm 2139: if (s->env != NULL) {
2140: for (i = 0; i < s->num_env; i++) {
1.265 djm 2141: free(s->env[i].name);
2142: free(s->env[i].val);
1.219 djm 2143: }
1.265 djm 2144: free(s->env);
1.173 djm 2145: }
1.9 markus 2146: session_proctitle(s);
1.237 djm 2147: session_unused(s->self);
1.2 markus 2148: }
2149:
2150: void
2151: session_close_by_pid(pid_t pid, int status)
2152: {
2153: Session *s = session_by_pid(pid);
2154: if (s == NULL) {
1.137 mpech 2155: debug("session_close_by_pid: no session for pid %ld",
2156: (long)pid);
1.2 markus 2157: return;
2158: }
2159: if (s->chanid != -1)
2160: session_exit_message(s, status);
1.187 djm 2161: if (s->ttyfd != -1)
2162: session_pty_cleanup(s);
1.197 djm 2163: s->pid = 0;
1.98 markus 2164: }
2165:
1.2 markus 2166: /*
2167: * this is called when a channel dies before
2168: * the session 'child' itself dies
2169: */
2170: void
2171: session_close_by_channel(int id, void *arg)
2172: {
2173: Session *s = session_by_channel(id);
1.187 djm 2174: u_int i;
1.184 djm 2175:
1.2 markus 2176: if (s == NULL) {
1.107 markus 2177: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2178: return;
2179: }
1.137 mpech 2180: debug("session_close_by_channel: channel %d child %ld",
2181: id, (long)s->pid);
1.107 markus 2182: if (s->pid != 0) {
2183: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2184: /*
2185: * delay detach of session, but release pty, since
2186: * the fd's to the child are already closed
2187: */
1.165 markus 2188: if (s->ttyfd != -1)
1.108 markus 2189: session_pty_cleanup(s);
1.107 markus 2190: return;
2191: }
2192: /* detach by removing callback */
1.2 markus 2193: channel_cancel_cleanup(s->chanid);
1.187 djm 2194:
2195: /* Close any X11 listeners associated with this session */
2196: if (s->x11_chanids != NULL) {
2197: for (i = 0; s->x11_chanids[i] != -1; i++) {
2198: session_close_x11(s->x11_chanids[i]);
2199: s->x11_chanids[i] = -1;
2200: }
2201: }
2202:
1.2 markus 2203: s->chanid = -1;
1.106 markus 2204: session_close(s);
2205: }
2206:
2207: void
1.130 provos 2208: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2209: {
2210: int i;
1.237 djm 2211: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2212: Session *s = &sessions[i];
1.130 provos 2213: if (s->used) {
2214: if (closefunc != NULL)
2215: closefunc(s);
2216: else
2217: session_close(s);
2218: }
1.2 markus 2219: }
1.9 markus 2220: }
2221:
1.94 itojun 2222: static char *
1.9 markus 2223: session_tty_list(void)
2224: {
2225: static char buf[1024];
2226: int i;
2227: buf[0] = '\0';
1.237 djm 2228: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2229: Session *s = &sessions[i];
2230: if (s->used && s->ttyfd != -1) {
2231: if (buf[0] != '\0')
2232: strlcat(buf, ",", sizeof buf);
2233: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2234: }
2235: }
2236: if (buf[0] == '\0')
2237: strlcpy(buf, "notty", sizeof buf);
2238: return buf;
2239: }
2240:
2241: void
2242: session_proctitle(Session *s)
2243: {
2244: if (s->pw == NULL)
2245: error("no user for session %d", s->self);
2246: else
2247: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2248: }
2249:
2250: int
2251: session_setup_x11fwd(Session *s)
2252: {
2253: struct stat st;
1.109 stevesk 2254: char display[512], auth_display[512];
1.272 djm 2255: char hostname[NI_MAXHOST];
1.184 djm 2256: u_int i;
1.81 markus 2257:
2258: if (no_x11_forwarding_flag) {
2259: packet_send_debug("X11 forwarding disabled in user configuration file.");
2260: return 0;
2261: }
2262: if (!options.x11_forwarding) {
2263: debug("X11 forwarding disabled in server configuration file.");
2264: return 0;
2265: }
1.275 djm 2266: if (options.xauth_location == NULL ||
1.81 markus 2267: (stat(options.xauth_location, &st) == -1)) {
2268: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2269: return 0;
2270: }
2271: if (options.use_login) {
2272: packet_send_debug("X11 forwarding disabled; "
2273: "not compatible with UseLogin=yes.");
1.81 markus 2274: return 0;
2275: }
1.87 markus 2276: if (s->display != NULL) {
1.81 markus 2277: debug("X11 display already set.");
2278: return 0;
2279: }
1.140 deraadt 2280: if (x11_create_display_inet(options.x11_display_offset,
2281: options.x11_use_localhost, s->single_connection,
1.184 djm 2282: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2283: debug("x11_create_display_inet failed.");
1.81 markus 2284: return 0;
1.184 djm 2285: }
2286: for (i = 0; s->x11_chanids[i] != -1; i++) {
2287: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2288: session_close_single_x11, 0);
1.81 markus 2289: }
1.109 stevesk 2290:
2291: /* Set up a suitable value for the DISPLAY variable. */
2292: if (gethostname(hostname, sizeof(hostname)) < 0)
2293: fatal("gethostname: %.100s", strerror(errno));
2294: /*
2295: * auth_display must be used as the displayname when the
2296: * authorization entry is added with xauth(1). This will be
2297: * different than the DISPLAY string for localhost displays.
2298: */
1.119 stevesk 2299: if (options.x11_use_localhost) {
1.140 deraadt 2300: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2301: s->display_number, s->screen);
1.140 deraadt 2302: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2303: s->display_number, s->screen);
1.109 stevesk 2304: s->display = xstrdup(display);
1.118 stevesk 2305: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2306: } else {
1.140 deraadt 2307: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2308: s->display_number, s->screen);
2309: s->display = xstrdup(display);
1.118 stevesk 2310: s->auth_display = xstrdup(display);
1.109 stevesk 2311: }
2312:
1.81 markus 2313: return 1;
1.2 markus 2314: }
2315:
1.94 itojun 2316: static void
1.49 markus 2317: do_authenticated2(Authctxt *authctxt)
1.2 markus 2318: {
1.97 markus 2319: server_loop2(authctxt);
1.165 markus 2320: }
2321:
2322: void
2323: do_cleanup(Authctxt *authctxt)
2324: {
2325: static int called = 0;
2326:
2327: debug("do_cleanup");
2328:
2329: /* no cleanup if we're in the child for login shell */
2330: if (is_child)
2331: return;
2332:
2333: /* avoid double cleanup */
2334: if (called)
2335: return;
2336: called = 1;
2337:
1.218 markus 2338: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2339: return;
2340: #ifdef KRB5
2341: if (options.kerberos_ticket_cleanup &&
2342: authctxt->krb5_ctx)
2343: krb5_cleanup_proc(authctxt);
1.161 markus 2344: #endif
1.165 markus 2345:
2346: #ifdef GSSAPI
2347: if (compat20 && options.gss_cleanup_creds)
2348: ssh_gssapi_cleanup_creds();
2349: #endif
2350:
2351: /* remove agent socket */
2352: auth_sock_cleanup_proc(authctxt->pw);
2353:
2354: /*
2355: * Cleanup ptys/utmp only if privsep is disabled,
2356: * or if running in monitor.
2357: */
2358: if (!use_privsep || mm_is_monitor())
2359: session_destroy_all(session_pty_cleanup2);
1.1 markus 2360: }
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