Annotation of src/usr.bin/ssh/session.c, Revision 1.281
1.281 ! djm 1: /* $OpenBSD: session.c,v 1.280 2016/02/16 03:37:48 djm Exp $ */
1.1 markus 2: /*
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.37 deraadt 5: *
6: * As far as I am concerned, the code I have written for this software
7: * can be used freely for any purpose. Any derived versions of this
8: * software must be clearly marked as such, and if the derived work is
9: * incompatible with the protocol description in the RFC file, it must be
10: * called by a name other than "ssh" or "Secure Shell".
11: *
1.2 markus 12: * SSH2 support by Markus Friedl.
1.95 markus 13: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.37 deraadt 14: *
15: * Redistribution and use in source and binary forms, with or without
16: * modification, are permitted provided that the following conditions
17: * are met:
18: * 1. Redistributions of source code must retain the above copyright
19: * notice, this list of conditions and the following disclaimer.
20: * 2. Redistributions in binary form must reproduce the above copyright
21: * notice, this list of conditions and the following disclaimer in the
22: * documentation and/or other materials provided with the distribution.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.2 markus 34: */
1.1 markus 35:
1.193 stevesk 36: #include <sys/types.h>
37: #include <sys/wait.h>
1.194 stevesk 38: #include <sys/un.h>
1.196 stevesk 39: #include <sys/stat.h>
1.207 stevesk 40: #include <sys/socket.h>
1.236 djm 41: #include <sys/queue.h>
1.192 stevesk 42:
1.209 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: {
1.281 ! djm 698: struct ssh *ssh = active_state; /* XXX */
1.237 djm 699: int ret;
1.280 djm 700: const char *forced = NULL, *tty = NULL;
701: char session_type[1024];
1.237 djm 702:
1.210 dtucker 703: if (options.adm_forced_command) {
704: original_command = command;
705: command = options.adm_forced_command;
1.267 djm 706: forced = "(config)";
1.210 dtucker 707: } else if (forced_command) {
1.90 markus 708: original_command = command;
709: command = forced_command;
1.267 djm 710: forced = "(key-option)";
711: }
712: if (forced != NULL) {
1.248 djm 713: if (IS_INTERNAL_SFTP(command)) {
714: s->is_subsystem = s->is_subsystem ?
715: SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
716: } else if (s->is_subsystem)
1.225 markus 717: s->is_subsystem = SUBSYSTEM_EXT;
1.267 djm 718: snprintf(session_type, sizeof(session_type),
719: "forced-command %s '%.900s'", forced, command);
720: } else if (s->is_subsystem) {
721: snprintf(session_type, sizeof(session_type),
722: "subsystem '%.900s'", s->subsys);
723: } else if (command == NULL) {
724: snprintf(session_type, sizeof(session_type), "shell");
725: } else {
726: /* NB. we don't log unforced commands to preserve privacy */
727: snprintf(session_type, sizeof(session_type), "command");
1.90 markus 728: }
1.163 markus 729:
1.267 djm 730: if (s->ttyfd != -1) {
731: tty = s->tty;
732: if (strncmp(tty, "/dev/", 5) == 0)
733: tty += 5;
734: }
735:
1.280 djm 736: verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
1.267 djm 737: session_type,
738: tty == NULL ? "" : " on ",
739: tty == NULL ? "" : tty,
740: s->pw->pw_name,
1.281 ! djm 741: ssh_remote_ipaddr(ssh),
! 742: ssh_remote_port(ssh),
1.280 djm 743: s->self);
1.267 djm 744:
1.163 markus 745: #ifdef GSSAPI
746: if (options.gss_authentication) {
747: temporarily_use_uid(s->pw);
748: ssh_gssapi_storecreds();
749: restore_uid();
750: }
751: #endif
1.90 markus 752: if (s->ttyfd != -1)
1.237 djm 753: ret = do_exec_pty(s, command);
1.90 markus 754: else
1.237 djm 755: ret = do_exec_no_pty(s, command);
1.90 markus 756:
1.92 markus 757: original_command = NULL;
1.179 dtucker 758:
759: /*
760: * Clear loginmsg: it's the child's responsibility to display
761: * it to the user, otherwise multiple sessions may accumulate
762: * multiple copies of the login messages.
763: */
764: buffer_clear(&loginmsg);
1.237 djm 765:
766: return ret;
1.90 markus 767: }
768:
769:
1.24 markus 770: /* administrative, login(1)-like work */
771: void
1.41 markus 772: do_login(Session *s, const char *command)
1.24 markus 773: {
1.281 ! djm 774: struct ssh *ssh = active_state; /* XXX */
1.24 markus 775: socklen_t fromlen;
776: struct sockaddr_storage from;
777: struct passwd * pw = s->pw;
778: pid_t pid = getpid();
779:
780: /*
781: * Get IP address of client. If the connection is not a socket, let
782: * the address be 0.0.0.0.
783: */
784: memset(&from, 0, sizeof(from));
1.148 stevesk 785: fromlen = sizeof(from);
1.24 markus 786: if (packet_connection_is_on_socket()) {
787: if (getpeername(packet_get_connection_in(),
1.200 deraadt 788: (struct sockaddr *)&from, &fromlen) < 0) {
1.24 markus 789: debug("getpeername: %.100s", strerror(errno));
1.165 markus 790: cleanup_exit(255);
1.24 markus 791: }
792: }
1.25 markus 793:
1.24 markus 794: /* Record that there was a login on that tty from the remote host. */
1.133 markus 795: if (!use_privsep)
796: record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
1.281 ! djm 797: session_get_remote_name_or_ip(ssh, utmp_len,
1.158 markus 798: options.use_dns),
1.148 stevesk 799: (struct sockaddr *)&from, fromlen);
1.24 markus 800:
1.73 djm 801: if (check_quietlogin(s, command))
1.24 markus 802: return;
1.73 djm 803:
1.179 dtucker 804: display_loginmsg();
1.73 djm 805:
806: do_motd();
807: }
808:
809: /*
810: * Display the message of the day.
811: */
812: void
813: do_motd(void)
814: {
815: FILE *f;
816: char buf[256];
817:
1.24 markus 818: if (options.print_motd) {
1.28 millert 819: f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
820: "/etc/motd"), "r");
1.24 markus 821: if (f) {
822: while (fgets(buf, sizeof(buf), f))
823: fputs(buf, stdout);
824: fclose(f);
825: }
1.2 markus 826: }
1.73 djm 827: }
828:
829:
830: /*
831: * Check for quiet login, either .hushlogin or command given.
832: */
833: int
834: check_quietlogin(Session *s, const char *command)
835: {
836: char buf[256];
1.96 dugsong 837: struct passwd *pw = s->pw;
1.73 djm 838: struct stat st;
839:
840: /* Return 1 if .hushlogin exists or a command given. */
841: if (command != NULL)
842: return 1;
843: snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
844: if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
845: return 1;
846: return 0;
1.1 markus 847: }
848:
849: /*
850: * Sets the value of the given variable in the environment. If the variable
1.244 tobias 851: * already exists, its value is overridden.
1.1 markus 852: */
1.161 markus 853: void
1.45 markus 854: child_set_env(char ***envp, u_int *envsizep, const char *name,
1.112 deraadt 855: const char *value)
1.1 markus 856: {
1.164 markus 857: char **env;
858: u_int envsize;
1.45 markus 859: u_int i, namelen;
1.1 markus 860:
1.271 djm 861: if (strchr(name, '=') != NULL) {
862: error("Invalid environment variable \"%.100s\"", name);
863: return;
864: }
865:
1.1 markus 866: /*
867: * Find the slot where the value should be stored. If the variable
868: * already exists, we reuse the slot; otherwise we append a new slot
869: * at the end of the array, expanding if necessary.
870: */
871: env = *envp;
872: namelen = strlen(name);
873: for (i = 0; env[i]; i++)
874: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
875: break;
876: if (env[i]) {
877: /* Reuse the slot. */
1.265 djm 878: free(env[i]);
1.1 markus 879: } else {
880: /* New variable. Expand if necessary. */
1.164 markus 881: envsize = *envsizep;
882: if (i >= envsize - 1) {
883: if (envsize >= 1000)
884: fatal("child_set_env: too many env vars");
885: envsize += 50;
1.278 deraadt 886: env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1.164 markus 887: *envsizep = envsize;
1.1 markus 888: }
889: /* Need to set the NULL pointer at end of array beyond the new slot. */
890: env[i + 1] = NULL;
891: }
892:
893: /* Allocate space and format the variable in the appropriate slot. */
894: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
895: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
896: }
897:
898: /*
899: * Reads environment variables from the given file and adds/overrides them
900: * into the environment. If the file does not exist, this does nothing.
901: * Otherwise, it must consist of empty lines, comments (line starts with '#')
902: * and assignments of the form name=value. No other forms are allowed.
903: */
1.94 itojun 904: static void
1.45 markus 905: read_environment_file(char ***env, u_int *envsize,
1.112 deraadt 906: const char *filename)
1.1 markus 907: {
908: FILE *f;
909: char buf[4096];
910: char *cp, *value;
1.142 deraadt 911: u_int lineno = 0;
1.1 markus 912:
913: f = fopen(filename, "r");
914: if (!f)
915: return;
916:
917: while (fgets(buf, sizeof(buf), f)) {
1.142 deraadt 918: if (++lineno > 1000)
919: fatal("Too many lines in environment file %s", filename);
1.1 markus 920: for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
921: ;
922: if (!*cp || *cp == '#' || *cp == '\n')
923: continue;
1.224 gilles 924:
925: cp[strcspn(cp, "\n")] = '\0';
926:
1.1 markus 927: value = strchr(cp, '=');
928: if (value == NULL) {
1.142 deraadt 929: fprintf(stderr, "Bad line %u in %.100s\n", lineno,
930: filename);
1.1 markus 931: continue;
932: }
1.14 deraadt 933: /*
934: * Replace the equals sign by nul, and advance value to
935: * the value string.
936: */
1.1 markus 937: *value = '\0';
938: value++;
939: child_set_env(env, envsize, cp, value);
940: }
941: fclose(f);
942: }
943:
1.127 markus 944: static char **
945: do_setup_env(Session *s, const char *shell)
1.1 markus 946: {
1.281 ! djm 947: struct ssh *ssh = active_state; /* XXX */
1.1 markus 948: char buf[256];
1.127 markus 949: u_int i, envsize;
1.154 markus 950: char **env, *laddr;
1.127 markus 951: struct passwd *pw = s->pw;
1.1 markus 952:
953: /* Initialize the environment. */
954: envsize = 100;
1.220 djm 955: env = xcalloc(envsize, sizeof(char *));
1.1 markus 956: env[0] = NULL;
957:
1.161 markus 958: #ifdef GSSAPI
1.168 djm 959: /* Allow any GSSAPI methods that we've used to alter
1.161 markus 960: * the childs environment as they see fit
961: */
962: ssh_gssapi_do_child(&env, &envsize);
963: #endif
964:
1.1 markus 965: if (!options.use_login) {
966: /* Set basic environment. */
1.173 djm 967: for (i = 0; i < s->num_env; i++)
1.178 deraadt 968: child_set_env(&env, &envsize, s->env[i].name,
1.173 djm 969: s->env[i].val);
970:
1.1 markus 971: child_set_env(&env, &envsize, "USER", pw->pw_name);
972: child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
973: child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1.145 markus 974: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
975: child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
976: else
977: child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1.1 markus 978:
979: snprintf(buf, sizeof buf, "%.200s/%.50s",
980: _PATH_MAILDIR, pw->pw_name);
981: child_set_env(&env, &envsize, "MAIL", buf);
982:
983: /* Normal systems set SHELL by default. */
984: child_set_env(&env, &envsize, "SHELL", shell);
985: }
986: if (getenv("TZ"))
987: child_set_env(&env, &envsize, "TZ", getenv("TZ"));
988:
989: /* Set custom environment options from RSA authentication. */
1.110 markus 990: if (!options.use_login) {
991: while (custom_environment) {
992: struct envstring *ce = custom_environment;
1.143 deraadt 993: char *str = ce->s;
1.127 markus 994:
1.143 deraadt 995: for (i = 0; str[i] != '=' && str[i]; i++)
1.110 markus 996: ;
1.143 deraadt 997: if (str[i] == '=') {
998: str[i] = 0;
999: child_set_env(&env, &envsize, str, str + i + 1);
1.110 markus 1000: }
1001: custom_environment = ce->next;
1.265 djm 1002: free(ce->s);
1003: free(ce);
1.1 markus 1004: }
1005: }
1006:
1.149 stevesk 1007: /* SSH_CLIENT deprecated */
1.1 markus 1008: snprintf(buf, sizeof buf, "%.50s %d %d",
1.281 ! djm 1009: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
! 1010: ssh_local_port(ssh));
1.1 markus 1011: child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1.149 stevesk 1012:
1.154 markus 1013: laddr = get_local_ipaddr(packet_get_connection_in());
1.149 stevesk 1014: snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1.281 ! djm 1015: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
! 1016: laddr, ssh_local_port(ssh));
1.265 djm 1017: free(laddr);
1.149 stevesk 1018: child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1.1 markus 1019:
1.60 markus 1020: if (s->ttyfd != -1)
1021: child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1022: if (s->term)
1023: child_set_env(&env, &envsize, "TERM", s->term);
1024: if (s->display)
1025: child_set_env(&env, &envsize, "DISPLAY", s->display);
1.34 markus 1026: if (original_command)
1027: child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1028: original_command);
1.96 dugsong 1029: #ifdef KRB5
1030: if (s->authctxt->krb5_ticket_file)
1031: child_set_env(&env, &envsize, "KRB5CCNAME",
1.112 deraadt 1032: s->authctxt->krb5_ticket_file);
1.96 dugsong 1033: #endif
1.136 markus 1034: if (auth_sock_name != NULL)
1.1 markus 1035: child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1.136 markus 1036: auth_sock_name);
1.1 markus 1037:
1038: /* read $HOME/.ssh/environment. */
1.146 markus 1039: if (options.permit_user_env && !options.use_login) {
1.14 deraadt 1040: snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1041: pw->pw_dir);
1.1 markus 1042: read_environment_file(&env, &envsize, buf);
1043: }
1044: if (debug_flag) {
1045: /* dump the environment */
1046: fprintf(stderr, "Environment:\n");
1047: for (i = 0; env[i]; i++)
1048: fprintf(stderr, " %.200s\n", env[i]);
1049: }
1.127 markus 1050: return env;
1051: }
1052:
1053: /*
1054: * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1055: * first in this order).
1056: */
1057: static void
1058: do_rc_files(Session *s, const char *shell)
1059: {
1060: FILE *f = NULL;
1061: char cmd[1024];
1062: int do_xauth;
1063: struct stat st;
1064:
1065: do_xauth =
1066: s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1067:
1.231 djm 1068: /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1.232 djm 1069: if (!s->is_subsystem && options.adm_forced_command == NULL &&
1.273 djm 1070: !no_user_rc && options.permit_user_rc &&
1071: stat(_PATH_SSH_USER_RC, &st) >= 0) {
1.127 markus 1072: snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1073: shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1074: if (debug_flag)
1075: fprintf(stderr, "Running %s\n", cmd);
1076: f = popen(cmd, "w");
1077: if (f) {
1078: if (do_xauth)
1079: fprintf(f, "%s %s\n", s->auth_proto,
1080: s->auth_data);
1081: pclose(f);
1082: } else
1083: fprintf(stderr, "Could not run %s\n",
1084: _PATH_SSH_USER_RC);
1085: } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1086: if (debug_flag)
1087: fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1088: _PATH_SSH_SYSTEM_RC);
1089: f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1090: if (f) {
1091: if (do_xauth)
1092: fprintf(f, "%s %s\n", s->auth_proto,
1093: s->auth_data);
1094: pclose(f);
1095: } else
1096: fprintf(stderr, "Could not run %s\n",
1097: _PATH_SSH_SYSTEM_RC);
1098: } else if (do_xauth && options.xauth_location != NULL) {
1099: /* Add authority data to .Xauthority if appropriate. */
1100: if (debug_flag) {
1101: fprintf(stderr,
1.151 stevesk 1102: "Running %.500s remove %.100s\n",
1.165 markus 1103: options.xauth_location, s->auth_display);
1.151 stevesk 1104: fprintf(stderr,
1105: "%.500s add %.100s %.100s %.100s\n",
1.127 markus 1106: options.xauth_location, s->auth_display,
1107: s->auth_proto, s->auth_data);
1108: }
1109: snprintf(cmd, sizeof cmd, "%s -q -",
1110: options.xauth_location);
1111: f = popen(cmd, "w");
1112: if (f) {
1.151 stevesk 1113: fprintf(f, "remove %s\n",
1114: s->auth_display);
1.127 markus 1115: fprintf(f, "add %s %s %s\n",
1116: s->auth_display, s->auth_proto,
1117: s->auth_data);
1118: pclose(f);
1119: } else {
1120: fprintf(stderr, "Could not run %s\n",
1121: cmd);
1122: }
1123: }
1124: }
1125:
1126: static void
1127: do_nologin(struct passwd *pw)
1128: {
1129: FILE *f = NULL;
1.251 dtucker 1130: char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1131: struct stat sb;
1.127 markus 1132:
1.260 guenther 1133: if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1.251 dtucker 1134: return;
1135: nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1136:
1137: if (stat(nl, &sb) == -1) {
1138: if (nl != def_nl)
1.265 djm 1139: free(nl);
1.251 dtucker 1140: return;
1141: }
1142:
1143: /* /etc/nologin exists. Print its contents if we can and exit. */
1144: logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1145: if ((f = fopen(nl, "r")) != NULL) {
1.127 markus 1146: while (fgets(buf, sizeof(buf), f))
1147: fputs(buf, stderr);
1148: fclose(f);
1149: }
1.251 dtucker 1150: exit(254);
1.127 markus 1151: }
1152:
1.226 djm 1153: /*
1154: * Chroot into a directory after checking it for safety: all path components
1155: * must be root-owned directories with strict permissions.
1156: */
1157: static void
1158: safely_chroot(const char *path, uid_t uid)
1159: {
1160: const char *cp;
1.277 deraadt 1161: char component[PATH_MAX];
1.226 djm 1162: struct stat st;
1163:
1164: if (*path != '/')
1165: fatal("chroot path does not begin at root");
1166: if (strlen(path) >= sizeof(component))
1167: fatal("chroot path too long");
1168:
1169: /*
1170: * Descend the path, checking that each component is a
1171: * root-owned directory with strict permissions.
1172: */
1173: for (cp = path; cp != NULL;) {
1174: if ((cp = strchr(cp, '/')) == NULL)
1175: strlcpy(component, path, sizeof(component));
1176: else {
1177: cp++;
1178: memcpy(component, path, cp - path);
1179: component[cp - path] = '\0';
1180: }
1181:
1182: debug3("%s: checking '%s'", __func__, component);
1183:
1184: if (stat(component, &st) != 0)
1185: fatal("%s: stat(\"%s\"): %s", __func__,
1186: component, strerror(errno));
1187: if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1188: fatal("bad ownership or modes for chroot "
1189: "directory %s\"%s\"",
1190: cp == NULL ? "" : "component ", component);
1191: if (!S_ISDIR(st.st_mode))
1192: fatal("chroot path %s\"%s\" is not a directory",
1193: cp == NULL ? "" : "component ", component);
1194:
1195: }
1196:
1197: if (chdir(path) == -1)
1198: fatal("Unable to chdir to chroot path \"%s\": "
1199: "%s", path, strerror(errno));
1200: if (chroot(path) == -1)
1201: fatal("chroot(\"%s\"): %s", path, strerror(errno));
1202: if (chdir("/") == -1)
1203: fatal("%s: chdir(/) after chroot: %s",
1204: __func__, strerror(errno));
1205: verbose("Changed root directory to \"%s\"", path);
1206: }
1207:
1.127 markus 1208: /* Set login name, uid, gid, and groups. */
1.130 provos 1209: void
1.127 markus 1210: do_setusercontext(struct passwd *pw)
1211: {
1.227 djm 1212: char *chroot_path, *tmp;
1213:
1.127 markus 1214: if (getuid() == 0 || geteuid() == 0) {
1.226 djm 1215: /* Prepare groups */
1.127 markus 1216: if (setusercontext(lc, pw, pw->pw_uid,
1.226 djm 1217: (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1.127 markus 1218: perror("unable to set user context");
1219: exit(1);
1220: }
1.226 djm 1221:
1.279 djm 1222: if (!in_chroot && options.chroot_directory != NULL &&
1.226 djm 1223: strcasecmp(options.chroot_directory, "none") != 0) {
1.227 djm 1224: tmp = tilde_expand_filename(options.chroot_directory,
1225: pw->pw_uid);
1226: chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1227: "u", pw->pw_name, (char *)NULL);
1.226 djm 1228: safely_chroot(chroot_path, pw->pw_uid);
1.227 djm 1229: free(tmp);
1.226 djm 1230: free(chroot_path);
1.264 djm 1231: /* Make sure we don't attempt to chroot again */
1232: free(options.chroot_directory);
1233: options.chroot_directory = NULL;
1.279 djm 1234: in_chroot = 1;
1.226 djm 1235: }
1236:
1237: /* Set UID */
1238: if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1239: perror("unable to set user context (setuser)");
1240: exit(1);
1241: }
1.264 djm 1242: } else if (options.chroot_directory != NULL &&
1243: strcasecmp(options.chroot_directory, "none") != 0) {
1244: fatal("server lacks privileges to chroot to ChrootDirectory");
1.263 dtucker 1245: }
1.264 djm 1246:
1.127 markus 1247: if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1248: fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1249: }
1250:
1.131 markus 1251: static void
1.172 markus 1252: do_pwchange(Session *s)
1253: {
1.179 dtucker 1254: fflush(NULL);
1.172 markus 1255: fprintf(stderr, "WARNING: Your password has expired.\n");
1256: if (s->ttyfd != -1) {
1.178 deraadt 1257: fprintf(stderr,
1.172 markus 1258: "You must change your password now and login again!\n");
1259: execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1260: perror("passwd");
1261: } else {
1262: fprintf(stderr,
1263: "Password change required but no TTY available.\n");
1264: }
1265: exit(1);
1266: }
1267:
1268: static void
1.130 provos 1269: launch_login(struct passwd *pw, const char *hostname)
1270: {
1271: /* Launch login(1). */
1272:
1273: execl("/usr/bin/login", "login", "-h", hostname,
1274: "-p", "-f", "--", pw->pw_name, (char *)NULL);
1275:
1276: /* Login couldn't be executed, die. */
1277:
1278: perror("login");
1279: exit(1);
1280: }
1281:
1.172 markus 1282: static void
1283: child_close_fds(void)
1284: {
1.276 djm 1285: extern int auth_sock;
1.266 markus 1286:
1.276 djm 1287: if (auth_sock != -1) {
1288: close(auth_sock);
1289: auth_sock = -1;
1.266 markus 1290: }
1291:
1.172 markus 1292: if (packet_get_connection_in() == packet_get_connection_out())
1293: close(packet_get_connection_in());
1294: else {
1295: close(packet_get_connection_in());
1296: close(packet_get_connection_out());
1297: }
1298: /*
1299: * Close all descriptors related to channels. They will still remain
1300: * open in the parent.
1301: */
1302: /* XXX better use close-on-exec? -markus */
1303: channel_close_all();
1304:
1305: /*
1306: * Close any extra file descriptors. Note that there may still be
1307: * descriptors left by system functions. They will be closed later.
1308: */
1309: endpwent();
1310:
1311: /*
1.188 djm 1312: * Close any extra open file descriptors so that we don't have them
1.172 markus 1313: * hanging around in clients. Note that we want to do this after
1314: * initgroups, because at least on Solaris 2.3 it leaves file
1315: * descriptors open.
1316: */
1.258 djm 1317: closefrom(STDERR_FILENO + 1);
1.172 markus 1318: }
1319:
1.127 markus 1320: /*
1321: * Performs common processing for the child, such as setting up the
1322: * environment, closing extra file descriptors, setting the user and group
1323: * ids, and executing the command or shell.
1324: */
1.225 markus 1325: #define ARGV_MAX 10
1.127 markus 1326: void
1327: do_child(Session *s, const char *command)
1328: {
1.281 ! djm 1329: struct ssh *ssh = active_state; /* XXX */
1.127 markus 1330: extern char **environ;
1331: char **env;
1.225 markus 1332: char *argv[ARGV_MAX];
1.127 markus 1333: const char *shell, *shell0, *hostname = NULL;
1334: struct passwd *pw = s->pw;
1.239 djm 1335: int r = 0;
1.127 markus 1336:
1337: /* remove hostkey from the child's memory */
1338: destroy_sensitive_data();
1339:
1.172 markus 1340: /* Force a password change */
1341: if (s->authctxt->force_pwchange) {
1342: do_setusercontext(pw);
1343: child_close_fds();
1344: do_pwchange(s);
1345: exit(1);
1346: }
1347:
1.127 markus 1348: /* login(1) is only called if we execute the login shell */
1349: if (options.use_login && command != NULL)
1350: options.use_login = 0;
1351:
1352: /*
1353: * Login(1) does this as well, and it needs uid 0 for the "-h"
1354: * switch, so we let login(1) to this for us.
1355: */
1356: if (!options.use_login) {
1357: do_nologin(pw);
1358: do_setusercontext(pw);
1359: }
1360:
1361: /*
1362: * Get the shell from the password data. An empty shell field is
1363: * legal, and means /bin/sh.
1364: */
1365: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1.152 markus 1366:
1367: /*
1368: * Make sure $SHELL points to the shell from the password file,
1369: * even if shell is overridden from login.conf
1370: */
1371: env = do_setup_env(s, shell);
1372:
1.127 markus 1373: shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1374:
1.26 millert 1375: /* we have to stash the hostname before we close our socket. */
1376: if (options.use_login)
1.281 ! djm 1377: hostname = session_get_remote_name_or_ip(ssh, utmp_len,
1.158 markus 1378: options.use_dns);
1.1 markus 1379: /*
1380: * Close the connection descriptors; note that this is the child, and
1381: * the server will still have the socket open, and it is important
1382: * that we do not shutdown it. Note that the descriptors cannot be
1383: * closed before building the environment, as we call
1.281 ! djm 1384: * ssh_remote_ipaddr there.
1.1 markus 1385: */
1.172 markus 1386: child_close_fds();
1.1 markus 1387:
1388: /*
1.125 deraadt 1389: * Must take new environment into use so that .ssh/rc,
1390: * /etc/ssh/sshrc and xauth are run in the proper environment.
1.1 markus 1391: */
1392: environ = env;
1.170 jakob 1393:
1394: #ifdef KRB5
1395: /*
1396: * At this point, we check to see if AFS is active and if we have
1397: * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1398: * if we can (and need to) extend the ticket into an AFS token. If
1399: * we don't do this, we run into potential problems if the user's
1400: * home directory is in AFS and it's not world-readable.
1401: */
1402:
1403: if (options.kerberos_get_afs_token && k_hasafs() &&
1.185 djm 1404: (s->authctxt->krb5_ctx != NULL)) {
1.170 jakob 1405: char cell[64];
1406:
1407: debug("Getting AFS token");
1408:
1409: k_setpag();
1410:
1411: if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1412: krb5_afslog(s->authctxt->krb5_ctx,
1413: s->authctxt->krb5_fwd_ccache, cell, NULL);
1414:
1415: krb5_afslog_home(s->authctxt->krb5_ctx,
1416: s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1417: }
1418: #endif
1.104 markus 1419:
1.188 djm 1420: /* Change current directory to the user's home directory. */
1.104 markus 1421: if (chdir(pw->pw_dir) < 0) {
1.239 djm 1422: /* Suppress missing homedir warning for chroot case */
1423: r = login_getcapbool(lc, "requirehome", 0);
1.279 djm 1424: if (r || !in_chroot) {
1.239 djm 1425: fprintf(stderr, "Could not chdir to home "
1426: "directory %s: %s\n", pw->pw_dir,
1427: strerror(errno));
1.279 djm 1428: }
1.239 djm 1429: if (r)
1.104 markus 1430: exit(1);
1431: }
1.230 djm 1432:
1433: closefrom(STDERR_FILENO + 1);
1.1 markus 1434:
1.127 markus 1435: if (!options.use_login)
1436: do_rc_files(s, shell);
1.67 markus 1437:
1438: /* restore SIGPIPE for child */
1.217 stevesk 1439: signal(SIGPIPE, SIG_DFL);
1.67 markus 1440:
1.248 djm 1441: if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1442: printf("This service allows sftp connections only.\n");
1443: fflush(NULL);
1444: exit(1);
1445: } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1.225 markus 1446: extern int optind, optreset;
1447: int i;
1448: char *p, *args;
1449:
1.246 stevesk 1450: setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1.243 millert 1451: args = xstrdup(command ? command : "sftp-server");
1.225 markus 1452: for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1453: if (i < ARGV_MAX - 1)
1454: argv[i++] = p;
1455: argv[i] = NULL;
1456: optind = optreset = 1;
1457: __progname = argv[0];
1.226 djm 1458: exit(sftp_server_main(i, argv, s->pw));
1.225 markus 1459: }
1.247 djm 1460:
1461: fflush(NULL);
1.225 markus 1462:
1.127 markus 1463: if (options.use_login) {
1.130 provos 1464: launch_login(pw, hostname);
1465: /* NEVERREACHED */
1.127 markus 1466: }
1467:
1468: /* Get the last component of the shell name. */
1469: if ((shell0 = strrchr(shell, '/')) != NULL)
1470: shell0++;
1471: else
1472: shell0 = shell;
1473:
1.1 markus 1474: /*
1475: * If we have no command, execute the shell. In this case, the shell
1476: * name to be passed in argv[0] is preceded by '-' to indicate that
1477: * this is a login shell.
1478: */
1479: if (!command) {
1.127 markus 1480: char argv0[256];
1.1 markus 1481:
1.127 markus 1482: /* Start the shell. Set initial character to '-'. */
1483: argv0[0] = '-';
1.1 markus 1484:
1.127 markus 1485: if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1.128 markus 1486: >= sizeof(argv0) - 1) {
1.127 markus 1487: errno = EINVAL;
1.1 markus 1488: perror(shell);
1489: exit(1);
1.127 markus 1490: }
1.1 markus 1491:
1.127 markus 1492: /* Execute the shell. */
1493: argv[0] = argv0;
1494: argv[1] = NULL;
1495: execve(shell, argv, env);
1496:
1497: /* Executing the shell failed. */
1498: perror(shell);
1499: exit(1);
1.1 markus 1500: }
1501: /*
1502: * Execute the command using the user's shell. This uses the -c
1503: * option to execute the command.
1504: */
1.127 markus 1505: argv[0] = (char *) shell0;
1.1 markus 1506: argv[1] = "-c";
1507: argv[2] = (char *) command;
1508: argv[3] = NULL;
1509: execve(shell, argv, env);
1510: perror(shell);
1511: exit(1);
1512: }
1513:
1.237 djm 1514: void
1515: session_unused(int id)
1516: {
1517: debug3("%s: session id %d unused", __func__, id);
1518: if (id >= options.max_sessions ||
1519: id >= sessions_nalloc) {
1520: fatal("%s: insane session id %d (max %d nalloc %d)",
1521: __func__, id, options.max_sessions, sessions_nalloc);
1522: }
1.270 tedu 1523: memset(&sessions[id], 0, sizeof(*sessions));
1.237 djm 1524: sessions[id].self = id;
1525: sessions[id].used = 0;
1526: sessions[id].chanid = -1;
1527: sessions[id].ptyfd = -1;
1528: sessions[id].ttyfd = -1;
1529: sessions[id].ptymaster = -1;
1530: sessions[id].x11_chanids = NULL;
1531: sessions[id].next_unused = sessions_first_unused;
1532: sessions_first_unused = id;
1533: }
1534:
1.1 markus 1535: Session *
1536: session_new(void)
1537: {
1.237 djm 1538: Session *s, *tmp;
1539:
1540: if (sessions_first_unused == -1) {
1541: if (sessions_nalloc >= options.max_sessions)
1542: return NULL;
1543: debug2("%s: allocate (allocated %d max %d)",
1544: __func__, sessions_nalloc, options.max_sessions);
1.278 deraadt 1545: tmp = xreallocarray(sessions, sessions_nalloc + 1,
1.237 djm 1546: sizeof(*sessions));
1547: if (tmp == NULL) {
1548: error("%s: cannot allocate %d sessions",
1549: __func__, sessions_nalloc + 1);
1550: return NULL;
1551: }
1552: sessions = tmp;
1553: session_unused(sessions_nalloc++);
1554: }
1555:
1556: if (sessions_first_unused >= sessions_nalloc ||
1557: sessions_first_unused < 0) {
1558: fatal("%s: insane first_unused %d max %d nalloc %d",
1559: __func__, sessions_first_unused, options.max_sessions,
1560: sessions_nalloc);
1561: }
1562:
1563: s = &sessions[sessions_first_unused];
1564: if (s->used) {
1565: fatal("%s: session %d already used",
1566: __func__, sessions_first_unused);
1567: }
1568: sessions_first_unused = s->next_unused;
1569: s->used = 1;
1570: s->next_unused = -1;
1571: debug("session_new: session %d", s->self);
1572:
1573: return s;
1.1 markus 1574: }
1575:
1.94 itojun 1576: static void
1.1 markus 1577: session_dump(void)
1578: {
1579: int i;
1.237 djm 1580: for (i = 0; i < sessions_nalloc; i++) {
1.1 markus 1581: Session *s = &sessions[i];
1.237 djm 1582:
1583: debug("dump: used %d next_unused %d session %d %p "
1584: "channel %d pid %ld",
1.1 markus 1585: s->used,
1.237 djm 1586: s->next_unused,
1.1 markus 1587: s->self,
1588: s,
1589: s->chanid,
1.137 mpech 1590: (long)s->pid);
1.1 markus 1591: }
1592: }
1593:
1.2 markus 1594: int
1.97 markus 1595: session_open(Authctxt *authctxt, int chanid)
1.2 markus 1596: {
1597: Session *s = session_new();
1598: debug("session_open: channel %d", chanid);
1599: if (s == NULL) {
1600: error("no more sessions");
1601: return 0;
1602: }
1.97 markus 1603: s->authctxt = authctxt;
1604: s->pw = authctxt->pw;
1.167 djm 1605: if (s->pw == NULL || !authctxt->valid)
1.54 stevesk 1606: fatal("no user for session %d", s->self);
1.2 markus 1607: debug("session_open: session %d: link with channel %d", s->self, chanid);
1608: s->chanid = chanid;
1609: return 1;
1610: }
1611:
1.130 provos 1612: Session *
1613: session_by_tty(char *tty)
1614: {
1615: int i;
1.237 djm 1616: for (i = 0; i < sessions_nalloc; i++) {
1.130 provos 1617: Session *s = &sessions[i];
1618: if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1619: debug("session_by_tty: session %d tty %s", i, tty);
1620: return s;
1621: }
1622: }
1623: debug("session_by_tty: unknown tty %.100s", tty);
1624: session_dump();
1625: return NULL;
1626: }
1627:
1.94 itojun 1628: static Session *
1.2 markus 1629: session_by_channel(int id)
1630: {
1631: int i;
1.237 djm 1632: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1633: Session *s = &sessions[i];
1634: if (s->used && s->chanid == id) {
1.237 djm 1635: debug("session_by_channel: session %d channel %d",
1636: i, id);
1.2 markus 1637: return s;
1638: }
1639: }
1640: debug("session_by_channel: unknown channel %d", id);
1641: session_dump();
1642: return NULL;
1643: }
1644:
1.94 itojun 1645: static Session *
1.184 djm 1646: session_by_x11_channel(int id)
1647: {
1648: int i, j;
1649:
1.237 djm 1650: for (i = 0; i < sessions_nalloc; i++) {
1.184 djm 1651: Session *s = &sessions[i];
1652:
1653: if (s->x11_chanids == NULL || !s->used)
1654: continue;
1655: for (j = 0; s->x11_chanids[j] != -1; j++) {
1656: if (s->x11_chanids[j] == id) {
1657: debug("session_by_x11_channel: session %d "
1658: "channel %d", s->self, id);
1659: return s;
1660: }
1661: }
1662: }
1663: debug("session_by_x11_channel: unknown channel %d", id);
1664: session_dump();
1665: return NULL;
1666: }
1667:
1668: static Session *
1.2 markus 1669: session_by_pid(pid_t pid)
1670: {
1671: int i;
1.137 mpech 1672: debug("session_by_pid: pid %ld", (long)pid);
1.237 djm 1673: for (i = 0; i < sessions_nalloc; i++) {
1.2 markus 1674: Session *s = &sessions[i];
1675: if (s->used && s->pid == pid)
1676: return s;
1677: }
1.137 mpech 1678: error("session_by_pid: unknown pid %ld", (long)pid);
1.2 markus 1679: session_dump();
1680: return NULL;
1681: }
1682:
1.94 itojun 1683: static int
1.2 markus 1684: session_window_change_req(Session *s)
1685: {
1686: s->col = packet_get_int();
1687: s->row = packet_get_int();
1688: s->xpixel = packet_get_int();
1689: s->ypixel = packet_get_int();
1.116 markus 1690: packet_check_eom();
1.2 markus 1691: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1692: return 1;
1693: }
1694:
1.94 itojun 1695: static int
1.2 markus 1696: session_pty_req(Session *s)
1697: {
1.45 markus 1698: u_int len;
1.72 stevesk 1699: int n_bytes;
1.132 markus 1700:
1.268 djm 1701: if (no_pty_flag || !options.permit_tty) {
1.86 markus 1702: debug("Allocating a pty not permitted for this authentication.");
1.19 markus 1703: return 0;
1.86 markus 1704: }
1705: if (s->ttyfd != -1) {
1706: packet_disconnect("Protocol error: you already have a pty.");
1.3 markus 1707: return 0;
1.86 markus 1708: }
1709:
1.2 markus 1710: s->term = packet_get_string(&len);
1.86 markus 1711:
1712: if (compat20) {
1713: s->col = packet_get_int();
1714: s->row = packet_get_int();
1715: } else {
1716: s->row = packet_get_int();
1717: s->col = packet_get_int();
1718: }
1.2 markus 1719: s->xpixel = packet_get_int();
1720: s->ypixel = packet_get_int();
1721:
1722: if (strcmp(s->term, "") == 0) {
1.265 djm 1723: free(s->term);
1.2 markus 1724: s->term = NULL;
1725: }
1.86 markus 1726:
1.2 markus 1727: /* Allocate a pty and open it. */
1.86 markus 1728: debug("Allocating pty.");
1.237 djm 1729: if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1730: sizeof(s->tty)))) {
1.265 djm 1731: free(s->term);
1.2 markus 1732: s->term = NULL;
1733: s->ptyfd = -1;
1734: s->ttyfd = -1;
1735: error("session_pty_req: session %d alloc failed", s->self);
1.3 markus 1736: return 0;
1.2 markus 1737: }
1738: debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1.86 markus 1739:
1740: /* for SSH1 the tty modes length is not given */
1741: if (!compat20)
1742: n_bytes = packet_remaining();
1743: tty_parse_modes(s->ttyfd, &n_bytes);
1744:
1.130 provos 1745: if (!use_privsep)
1746: pty_setowner(s->pw, s->tty);
1.86 markus 1747:
1748: /* Set window size from the packet. */
1.2 markus 1749: pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1750:
1.116 markus 1751: packet_check_eom();
1.9 markus 1752: session_proctitle(s);
1.2 markus 1753: return 1;
1754: }
1755:
1.94 itojun 1756: static int
1.7 markus 1757: session_subsystem_req(Session *s)
1758: {
1.105 markus 1759: struct stat st;
1.45 markus 1760: u_int len;
1.7 markus 1761: int success = 0;
1.267 djm 1762: char *prog, *cmd;
1.182 djm 1763: u_int i;
1.7 markus 1764:
1.267 djm 1765: s->subsys = packet_get_string(&len);
1.116 markus 1766: packet_check_eom();
1.267 djm 1767: debug2("subsystem request for %.100s by user %s", s->subsys,
1.255 djm 1768: s->pw->pw_name);
1.18 jakob 1769:
1770: for (i = 0; i < options.num_subsystems; i++) {
1.267 djm 1771: if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1.205 djm 1772: prog = options.subsystem_command[i];
1773: cmd = options.subsystem_args[i];
1.249 dtucker 1774: if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1.225 markus 1775: s->is_subsystem = SUBSYSTEM_INT_SFTP;
1.249 dtucker 1776: debug("subsystem: %s", prog);
1.225 markus 1777: } else {
1.249 dtucker 1778: if (stat(prog, &st) < 0)
1779: debug("subsystem: cannot stat %s: %s",
1780: prog, strerror(errno));
1.225 markus 1781: s->is_subsystem = SUBSYSTEM_EXT;
1.249 dtucker 1782: debug("subsystem: exec() %s", cmd);
1.105 markus 1783: }
1.237 djm 1784: success = do_exec(s, cmd) == 0;
1.122 markus 1785: break;
1.18 jakob 1786: }
1787: }
1788:
1789: if (!success)
1.267 djm 1790: logit("subsystem request for %.100s by user %s failed, "
1791: "subsystem not found", s->subsys, s->pw->pw_name);
1.7 markus 1792:
1793: return success;
1794: }
1795:
1.94 itojun 1796: static int
1.7 markus 1797: session_x11_req(Session *s)
1798: {
1.81 markus 1799: int success;
1.7 markus 1800:
1.184 djm 1801: if (s->auth_proto != NULL || s->auth_data != NULL) {
1802: error("session_x11_req: session %d: "
1.190 stevesk 1803: "x11 forwarding already active", s->self);
1.184 djm 1804: return 0;
1805: }
1.7 markus 1806: s->single_connection = packet_get_char();
1807: s->auth_proto = packet_get_string(NULL);
1808: s->auth_data = packet_get_string(NULL);
1809: s->screen = packet_get_int();
1.116 markus 1810: packet_check_eom();
1.7 markus 1811:
1.81 markus 1812: success = session_setup_x11fwd(s);
1813: if (!success) {
1.265 djm 1814: free(s->auth_proto);
1815: free(s->auth_data);
1.84 markus 1816: s->auth_proto = NULL;
1817: s->auth_data = NULL;
1.7 markus 1818: }
1.81 markus 1819: return success;
1.7 markus 1820: }
1821:
1.94 itojun 1822: static int
1.19 markus 1823: session_shell_req(Session *s)
1824: {
1.116 markus 1825: packet_check_eom();
1.237 djm 1826: return do_exec(s, NULL) == 0;
1.19 markus 1827: }
1828:
1.94 itojun 1829: static int
1.19 markus 1830: session_exec_req(Session *s)
1831: {
1.237 djm 1832: u_int len, success;
1833:
1.19 markus 1834: char *command = packet_get_string(&len);
1.116 markus 1835: packet_check_eom();
1.237 djm 1836: success = do_exec(s, command) == 0;
1.265 djm 1837: free(command);
1.237 djm 1838: return success;
1.19 markus 1839: }
1840:
1.94 itojun 1841: static int
1.157 markus 1842: session_break_req(Session *s)
1843: {
1844:
1.175 deraadt 1845: packet_get_int(); /* ignored */
1.157 markus 1846: packet_check_eom();
1847:
1.259 djm 1848: if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
1.157 markus 1849: return 0;
1850: return 1;
1851: }
1852:
1853: static int
1.173 djm 1854: session_env_req(Session *s)
1855: {
1856: char *name, *val;
1857: u_int name_len, val_len, i;
1858:
1.271 djm 1859: name = packet_get_cstring(&name_len);
1860: val = packet_get_cstring(&val_len);
1.173 djm 1861: packet_check_eom();
1862:
1863: /* Don't set too many environment variables */
1864: if (s->num_env > 128) {
1865: debug2("Ignoring env request %s: too many env vars", name);
1866: goto fail;
1867: }
1868:
1869: for (i = 0; i < options.num_accept_env; i++) {
1870: if (match_pattern(name, options.accept_env[i])) {
1871: debug2("Setting env %d: %s=%s", s->num_env, name, val);
1.278 deraadt 1872: s->env = xreallocarray(s->env, s->num_env + 1,
1.201 djm 1873: sizeof(*s->env));
1.173 djm 1874: s->env[s->num_env].name = name;
1875: s->env[s->num_env].val = val;
1876: s->num_env++;
1877: return (1);
1878: }
1879: }
1880: debug2("Ignoring env request %s: disallowed name", name);
1881:
1882: fail:
1.265 djm 1883: free(name);
1884: free(val);
1.173 djm 1885: return (0);
1886: }
1887:
1888: static int
1.43 markus 1889: session_auth_agent_req(Session *s)
1890: {
1891: static int called = 0;
1.116 markus 1892: packet_check_eom();
1.235 pyr 1893: if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
1.44 markus 1894: debug("session_auth_agent_req: no_agent_forwarding_flag");
1895: return 0;
1896: }
1.43 markus 1897: if (called) {
1898: return 0;
1899: } else {
1900: called = 1;
1901: return auth_input_request_forwarding(s->pw);
1902: }
1903: }
1904:
1.123 markus 1905: int
1906: session_input_channel_req(Channel *c, const char *rtype)
1.2 markus 1907: {
1908: int success = 0;
1909: Session *s;
1910:
1.123 markus 1911: if ((s = session_by_channel(c->self)) == NULL) {
1.155 itojun 1912: logit("session_input_channel_req: no session %d req %.100s",
1.123 markus 1913: c->self, rtype);
1914: return 0;
1915: }
1916: debug("session_input_channel_req: session %d req %s", s->self, rtype);
1.2 markus 1917:
1918: /*
1.64 markus 1919: * a session is in LARVAL state until a shell, a command
1920: * or a subsystem is executed
1.2 markus 1921: */
1922: if (c->type == SSH_CHANNEL_LARVAL) {
1923: if (strcmp(rtype, "shell") == 0) {
1.19 markus 1924: success = session_shell_req(s);
1.2 markus 1925: } else if (strcmp(rtype, "exec") == 0) {
1.19 markus 1926: success = session_exec_req(s);
1.2 markus 1927: } else if (strcmp(rtype, "pty-req") == 0) {
1.221 stevesk 1928: success = session_pty_req(s);
1.7 markus 1929: } else if (strcmp(rtype, "x11-req") == 0) {
1930: success = session_x11_req(s);
1.43 markus 1931: } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1932: success = session_auth_agent_req(s);
1.7 markus 1933: } else if (strcmp(rtype, "subsystem") == 0) {
1934: success = session_subsystem_req(s);
1.173 djm 1935: } else if (strcmp(rtype, "env") == 0) {
1936: success = session_env_req(s);
1.2 markus 1937: }
1938: }
1939: if (strcmp(rtype, "window-change") == 0) {
1940: success = session_window_change_req(s);
1.177 djm 1941: } else if (strcmp(rtype, "break") == 0) {
1942: success = session_break_req(s);
1.2 markus 1943: }
1.177 djm 1944:
1.123 markus 1945: return success;
1.2 markus 1946: }
1947:
1948: void
1.256 djm 1949: session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
1950: int is_tty)
1.2 markus 1951: {
1952: if (!compat20)
1953: fatal("session_set_fds: called for proto != 2.0");
1954: /*
1955: * now that have a child and a pipe to the child,
1956: * we can activate our channel and register the fd's
1957: */
1958: if (s->chanid == -1)
1959: fatal("no channel for session %d", s->self);
1960: channel_set_fds(s->chanid,
1961: fdout, fdin, fderr,
1.256 djm 1962: ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1.241 dtucker 1963: 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
1.2 markus 1964: }
1965:
1.85 markus 1966: /*
1967: * Function to perform pty cleanup. Also called if we get aborted abnormally
1968: * (e.g., due to a dropped connection).
1969: */
1.130 provos 1970: void
1.165 markus 1971: session_pty_cleanup2(Session *s)
1.1 markus 1972: {
1.85 markus 1973: if (s == NULL) {
1974: error("session_pty_cleanup: no session");
1975: return;
1976: }
1977: if (s->ttyfd == -1)
1.1 markus 1978: return;
1979:
1.54 stevesk 1980: debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1.1 markus 1981:
1982: /* Record that the user has logged out. */
1.85 markus 1983: if (s->pid != 0)
1984: record_logout(s->pid, s->tty);
1.1 markus 1985:
1986: /* Release the pseudo-tty. */
1.130 provos 1987: if (getuid() == 0)
1988: pty_release(s->tty);
1.1 markus 1989:
1990: /*
1991: * Close the server side of the socket pairs. We must do this after
1992: * the pty cleanup, so that another process doesn't get this pty
1993: * while we're still cleaning up.
1994: */
1.237 djm 1995: if (s->ptymaster != -1 && close(s->ptymaster) < 0)
1996: error("close(s->ptymaster/%d): %s",
1997: s->ptymaster, strerror(errno));
1.108 markus 1998:
1999: /* unlink pty from session */
2000: s->ttyfd = -1;
1.2 markus 2001: }
2002:
1.130 provos 2003: void
1.165 markus 2004: session_pty_cleanup(Session *s)
1.130 provos 2005: {
1.165 markus 2006: PRIVSEP(session_pty_cleanup2(s));
1.130 provos 2007: }
2008:
1.147 markus 2009: static char *
2010: sig2name(int sig)
2011: {
2012: #define SSH_SIG(x) if (sig == SIG ## x) return #x
2013: SSH_SIG(ABRT);
2014: SSH_SIG(ALRM);
2015: SSH_SIG(FPE);
2016: SSH_SIG(HUP);
2017: SSH_SIG(ILL);
2018: SSH_SIG(INT);
2019: SSH_SIG(KILL);
2020: SSH_SIG(PIPE);
2021: SSH_SIG(QUIT);
2022: SSH_SIG(SEGV);
2023: SSH_SIG(TERM);
2024: SSH_SIG(USR1);
2025: SSH_SIG(USR2);
2026: #undef SSH_SIG
2027: return "SIG@openssh.com";
2028: }
2029:
1.94 itojun 2030: static void
1.184 djm 2031: session_close_x11(int id)
2032: {
2033: Channel *c;
2034:
1.189 markus 2035: if ((c = channel_by_id(id)) == NULL) {
1.184 djm 2036: debug("session_close_x11: x11 channel %d missing", id);
2037: } else {
2038: /* Detach X11 listener */
2039: debug("session_close_x11: detach x11 channel %d", id);
2040: channel_cancel_cleanup(id);
2041: if (c->ostate != CHAN_OUTPUT_CLOSED)
2042: chan_mark_dead(c);
2043: }
2044: }
2045:
2046: static void
2047: session_close_single_x11(int id, void *arg)
2048: {
2049: Session *s;
2050: u_int i;
2051:
2052: debug3("session_close_single_x11: channel %d", id);
2053: channel_cancel_cleanup(id);
1.221 stevesk 2054: if ((s = session_by_x11_channel(id)) == NULL)
1.184 djm 2055: fatal("session_close_single_x11: no x11 channel %d", id);
2056: for (i = 0; s->x11_chanids[i] != -1; i++) {
2057: debug("session_close_single_x11: session %d: "
2058: "closing channel %d", s->self, s->x11_chanids[i]);
2059: /*
2060: * The channel "id" is already closing, but make sure we
2061: * close all of its siblings.
2062: */
2063: if (s->x11_chanids[i] != id)
2064: session_close_x11(s->x11_chanids[i]);
2065: }
1.265 djm 2066: free(s->x11_chanids);
1.184 djm 2067: s->x11_chanids = NULL;
1.265 djm 2068: free(s->display);
2069: s->display = NULL;
2070: free(s->auth_proto);
2071: s->auth_proto = NULL;
2072: free(s->auth_data);
2073: s->auth_data = NULL;
2074: free(s->auth_display);
2075: s->auth_display = NULL;
1.184 djm 2076: }
2077:
2078: static void
1.2 markus 2079: session_exit_message(Session *s, int status)
2080: {
2081: Channel *c;
1.124 markus 2082:
2083: if ((c = channel_lookup(s->chanid)) == NULL)
1.85 markus 2084: fatal("session_exit_message: session %d: no channel %d",
1.2 markus 2085: s->self, s->chanid);
1.137 mpech 2086: debug("session_exit_message: session %d channel %d pid %ld",
2087: s->self, s->chanid, (long)s->pid);
1.2 markus 2088:
2089: if (WIFEXITED(status)) {
1.124 markus 2090: channel_request_start(s->chanid, "exit-status", 0);
1.2 markus 2091: packet_put_int(WEXITSTATUS(status));
2092: packet_send();
2093: } else if (WIFSIGNALED(status)) {
1.124 markus 2094: channel_request_start(s->chanid, "exit-signal", 0);
1.147 markus 2095: packet_put_cstring(sig2name(WTERMSIG(status)));
1.229 markus 2096: packet_put_char(WCOREDUMP(status)? 1 : 0);
1.2 markus 2097: packet_put_cstring("");
2098: packet_put_cstring("");
2099: packet_send();
2100: } else {
2101: /* Some weird exit cause. Just exit. */
2102: packet_disconnect("wait returned status %04x.", status);
2103: }
2104:
2105: /* disconnect channel */
2106: debug("session_exit_message: release channel %d", s->chanid);
1.187 djm 2107:
2108: /*
2109: * Adjust cleanup callback attachment to send close messages when
1.199 deraadt 2110: * the channel gets EOF. The session will be then be closed
1.187 djm 2111: * by session_close_by_channel when the childs close their fds.
2112: */
2113: channel_register_cleanup(c->self, session_close_by_channel, 1);
2114:
1.5 markus 2115: /*
2116: * emulate a write failure with 'chan_write_failed', nobody will be
2117: * interested in data we write.
2118: * Note that we must not call 'chan_read_failed', since there could
2119: * be some more data waiting in the pipe.
2120: */
1.8 markus 2121: if (c->ostate != CHAN_OUTPUT_CLOSED)
2122: chan_write_failed(c);
1.2 markus 2123: }
2124:
1.130 provos 2125: void
1.85 markus 2126: session_close(Session *s)
1.2 markus 2127: {
1.281 ! djm 2128: struct ssh *ssh = active_state; /* XXX */
1.182 djm 2129: u_int i;
1.173 djm 2130:
1.280 djm 2131: verbose("Close session: user %s from %.200s port %d id %d",
2132: s->pw->pw_name,
1.281 ! djm 2133: ssh_remote_ipaddr(ssh),
! 2134: ssh_remote_port(ssh),
1.280 djm 2135: s->self);
2136:
1.165 markus 2137: if (s->ttyfd != -1)
1.85 markus 2138: session_pty_cleanup(s);
1.265 djm 2139: free(s->term);
2140: free(s->display);
2141: free(s->x11_chanids);
2142: free(s->auth_display);
2143: free(s->auth_data);
2144: free(s->auth_proto);
1.267 djm 2145: free(s->subsys);
1.219 djm 2146: if (s->env != NULL) {
2147: for (i = 0; i < s->num_env; i++) {
1.265 djm 2148: free(s->env[i].name);
2149: free(s->env[i].val);
1.219 djm 2150: }
1.265 djm 2151: free(s->env);
1.173 djm 2152: }
1.9 markus 2153: session_proctitle(s);
1.237 djm 2154: session_unused(s->self);
1.2 markus 2155: }
2156:
2157: void
2158: session_close_by_pid(pid_t pid, int status)
2159: {
2160: Session *s = session_by_pid(pid);
2161: if (s == NULL) {
1.137 mpech 2162: debug("session_close_by_pid: no session for pid %ld",
2163: (long)pid);
1.2 markus 2164: return;
2165: }
2166: if (s->chanid != -1)
2167: session_exit_message(s, status);
1.187 djm 2168: if (s->ttyfd != -1)
2169: session_pty_cleanup(s);
1.197 djm 2170: s->pid = 0;
1.98 markus 2171: }
2172:
1.2 markus 2173: /*
2174: * this is called when a channel dies before
2175: * the session 'child' itself dies
2176: */
2177: void
2178: session_close_by_channel(int id, void *arg)
2179: {
2180: Session *s = session_by_channel(id);
1.187 djm 2181: u_int i;
1.184 djm 2182:
1.2 markus 2183: if (s == NULL) {
1.107 markus 2184: debug("session_close_by_channel: no session for id %d", id);
1.2 markus 2185: return;
2186: }
1.137 mpech 2187: debug("session_close_by_channel: channel %d child %ld",
2188: id, (long)s->pid);
1.107 markus 2189: if (s->pid != 0) {
2190: debug("session_close_by_channel: channel %d: has child", id);
1.108 markus 2191: /*
2192: * delay detach of session, but release pty, since
2193: * the fd's to the child are already closed
2194: */
1.165 markus 2195: if (s->ttyfd != -1)
1.108 markus 2196: session_pty_cleanup(s);
1.107 markus 2197: return;
2198: }
2199: /* detach by removing callback */
1.2 markus 2200: channel_cancel_cleanup(s->chanid);
1.187 djm 2201:
2202: /* Close any X11 listeners associated with this session */
2203: if (s->x11_chanids != NULL) {
2204: for (i = 0; s->x11_chanids[i] != -1; i++) {
2205: session_close_x11(s->x11_chanids[i]);
2206: s->x11_chanids[i] = -1;
2207: }
2208: }
2209:
1.2 markus 2210: s->chanid = -1;
1.106 markus 2211: session_close(s);
2212: }
2213:
2214: void
1.130 provos 2215: session_destroy_all(void (*closefunc)(Session *))
1.106 markus 2216: {
2217: int i;
1.237 djm 2218: for (i = 0; i < sessions_nalloc; i++) {
1.106 markus 2219: Session *s = &sessions[i];
1.130 provos 2220: if (s->used) {
2221: if (closefunc != NULL)
2222: closefunc(s);
2223: else
2224: session_close(s);
2225: }
1.2 markus 2226: }
1.9 markus 2227: }
2228:
1.94 itojun 2229: static char *
1.9 markus 2230: session_tty_list(void)
2231: {
2232: static char buf[1024];
2233: int i;
2234: buf[0] = '\0';
1.237 djm 2235: for (i = 0; i < sessions_nalloc; i++) {
1.9 markus 2236: Session *s = &sessions[i];
2237: if (s->used && s->ttyfd != -1) {
2238: if (buf[0] != '\0')
2239: strlcat(buf, ",", sizeof buf);
2240: strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
2241: }
2242: }
2243: if (buf[0] == '\0')
2244: strlcpy(buf, "notty", sizeof buf);
2245: return buf;
2246: }
2247:
2248: void
2249: session_proctitle(Session *s)
2250: {
2251: if (s->pw == NULL)
2252: error("no user for session %d", s->self);
2253: else
2254: setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1.81 markus 2255: }
2256:
2257: int
2258: session_setup_x11fwd(Session *s)
2259: {
2260: struct stat st;
1.109 stevesk 2261: char display[512], auth_display[512];
1.272 djm 2262: char hostname[NI_MAXHOST];
1.184 djm 2263: u_int i;
1.81 markus 2264:
2265: if (no_x11_forwarding_flag) {
2266: packet_send_debug("X11 forwarding disabled in user configuration file.");
2267: return 0;
2268: }
2269: if (!options.x11_forwarding) {
2270: debug("X11 forwarding disabled in server configuration file.");
2271: return 0;
2272: }
1.275 djm 2273: if (options.xauth_location == NULL ||
1.81 markus 2274: (stat(options.xauth_location, &st) == -1)) {
2275: packet_send_debug("No xauth program; cannot forward with spoofing.");
1.91 markus 2276: return 0;
2277: }
2278: if (options.use_login) {
2279: packet_send_debug("X11 forwarding disabled; "
2280: "not compatible with UseLogin=yes.");
1.81 markus 2281: return 0;
2282: }
1.87 markus 2283: if (s->display != NULL) {
1.81 markus 2284: debug("X11 display already set.");
2285: return 0;
2286: }
1.140 deraadt 2287: if (x11_create_display_inet(options.x11_display_offset,
2288: options.x11_use_localhost, s->single_connection,
1.184 djm 2289: &s->display_number, &s->x11_chanids) == -1) {
1.87 markus 2290: debug("x11_create_display_inet failed.");
1.81 markus 2291: return 0;
1.184 djm 2292: }
2293: for (i = 0; s->x11_chanids[i] != -1; i++) {
2294: channel_register_cleanup(s->x11_chanids[i],
1.187 djm 2295: session_close_single_x11, 0);
1.81 markus 2296: }
1.109 stevesk 2297:
2298: /* Set up a suitable value for the DISPLAY variable. */
2299: if (gethostname(hostname, sizeof(hostname)) < 0)
2300: fatal("gethostname: %.100s", strerror(errno));
2301: /*
2302: * auth_display must be used as the displayname when the
2303: * authorization entry is added with xauth(1). This will be
2304: * different than the DISPLAY string for localhost displays.
2305: */
1.119 stevesk 2306: if (options.x11_use_localhost) {
1.140 deraadt 2307: snprintf(display, sizeof display, "localhost:%u.%u",
1.109 stevesk 2308: s->display_number, s->screen);
1.140 deraadt 2309: snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
1.118 stevesk 2310: s->display_number, s->screen);
1.109 stevesk 2311: s->display = xstrdup(display);
1.118 stevesk 2312: s->auth_display = xstrdup(auth_display);
1.109 stevesk 2313: } else {
1.140 deraadt 2314: snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
1.109 stevesk 2315: s->display_number, s->screen);
2316: s->display = xstrdup(display);
1.118 stevesk 2317: s->auth_display = xstrdup(display);
1.109 stevesk 2318: }
2319:
1.81 markus 2320: return 1;
1.2 markus 2321: }
2322:
1.94 itojun 2323: static void
1.49 markus 2324: do_authenticated2(Authctxt *authctxt)
1.2 markus 2325: {
1.97 markus 2326: server_loop2(authctxt);
1.165 markus 2327: }
2328:
2329: void
2330: do_cleanup(Authctxt *authctxt)
2331: {
2332: static int called = 0;
2333:
2334: debug("do_cleanup");
2335:
2336: /* no cleanup if we're in the child for login shell */
2337: if (is_child)
2338: return;
2339:
2340: /* avoid double cleanup */
2341: if (called)
2342: return;
2343: called = 1;
2344:
1.218 markus 2345: if (authctxt == NULL || !authctxt->authenticated)
1.165 markus 2346: return;
2347: #ifdef KRB5
2348: if (options.kerberos_ticket_cleanup &&
2349: authctxt->krb5_ctx)
2350: krb5_cleanup_proc(authctxt);
1.161 markus 2351: #endif
1.165 markus 2352:
2353: #ifdef GSSAPI
2354: if (compat20 && options.gss_cleanup_creds)
2355: ssh_gssapi_cleanup_creds();
2356: #endif
2357:
2358: /* remove agent socket */
2359: auth_sock_cleanup_proc(authctxt->pw);
2360:
2361: /*
2362: * Cleanup ptys/utmp only if privsep is disabled,
2363: * or if running in monitor.
2364: */
2365: if (!use_privsep || mm_is_monitor())
2366: session_destroy_all(session_pty_cleanup2);
1.1 markus 2367: }
1.281 ! djm 2368:
! 2369: /* Return a name for the remote host that fits inside utmp_size */
! 2370:
! 2371: const char *
! 2372: session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns)
! 2373: {
! 2374: const char *remote = "";
! 2375:
! 2376: if (utmp_size > 0)
! 2377: remote = auth_get_canonical_hostname(ssh, use_dns);
! 2378: if (utmp_size == 0 || strlen(remote) > utmp_size)
! 2379: remote = ssh_remote_ipaddr(ssh);
! 2380: return remote;
! 2381: }
! 2382:
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