Annotation of src/usr.bin/ssh/sshd.c, Revision 1.477
1.477 ! dtucker 1: /* $OpenBSD: sshd.c,v 1.476 2016/09/28 16:33:07 djm Exp $ */
1.86 markus 2: /*
1.65 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
1.126 deraadt 6: * This program is the ssh daemon. It listens for connections from clients,
7: * and performs authentication, executes use commands or shell, and forwards
1.65 deraadt 8: * information to/from the application to the user client over an encrypted
1.126 deraadt 9: * connection. This can also handle forwarding of X11, TCP/IP, and
10: * authentication agent connections.
1.98 markus 11: *
1.126 deraadt 12: * As far as I am concerned, the code I have written for this software
13: * can be used freely for any purpose. Any derived versions of this
14: * software must be clearly marked as such, and if the derived work is
15: * incompatible with the protocol description in the RFC file, it must be
16: * called by a name other than "ssh" or "Secure Shell".
17: *
18: * SSH2 implementation:
1.231 provos 19: * Privilege Separation:
1.126 deraadt 20: *
1.231 provos 21: * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
22: * Copyright (c) 2002 Niels Provos. All rights reserved.
1.126 deraadt 23: *
24: * Redistribution and use in source and binary forms, with or without
25: * modification, are permitted provided that the following conditions
26: * are met:
27: * 1. Redistributions of source code must retain the above copyright
28: * notice, this list of conditions and the following disclaimer.
29: * 2. Redistributions in binary form must reproduce the above copyright
30: * notice, this list of conditions and the following disclaimer in the
31: * documentation and/or other materials provided with the distribution.
32: *
33: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.65 deraadt 43: */
1.1 deraadt 44:
1.343 deraadt 45: #include <sys/types.h>
1.320 stevesk 46: #include <sys/ioctl.h>
1.321 stevesk 47: #include <sys/wait.h>
1.343 deraadt 48: #include <sys/tree.h>
1.323 stevesk 49: #include <sys/stat.h>
1.334 stevesk 50: #include <sys/socket.h>
1.340 stevesk 51: #include <sys/time.h>
1.357 djm 52: #include <sys/queue.h>
1.319 stevesk 53:
1.336 stevesk 54: #include <errno.h>
1.335 stevesk 55: #include <fcntl.h>
1.338 stevesk 56: #include <netdb.h>
1.319 stevesk 57: #include <paths.h>
1.333 stevesk 58: #include <pwd.h>
1.322 stevesk 59: #include <signal.h>
1.342 stevesk 60: #include <stdio.h>
1.341 stevesk 61: #include <stdlib.h>
1.339 stevesk 62: #include <string.h>
1.344 dtucker 63: #include <unistd.h>
1.438 deraadt 64: #include <limits.h>
1.1 deraadt 65:
1.426 markus 66: #ifdef WITH_OPENSSL
1.155 markus 67: #include <openssl/bn.h>
1.426 markus 68: #endif
1.155 markus 69:
1.343 deraadt 70: #include "xmalloc.h"
1.155 markus 71: #include "ssh.h"
72: #include "ssh2.h"
1.1 deraadt 73: #include "rsa.h"
1.171 djm 74: #include "sshpty.h"
1.1 deraadt 75: #include "packet.h"
1.155 markus 76: #include "log.h"
1.343 deraadt 77: #include "buffer.h"
1.428 millert 78: #include "misc.h"
1.454 markus 79: #include "match.h"
1.1 deraadt 80: #include "servconf.h"
81: #include "uidswap.h"
1.33 markus 82: #include "compat.h"
1.155 markus 83: #include "cipher.h"
1.415 markus 84: #include "digest.h"
1.343 deraadt 85: #include "key.h"
1.98 markus 86: #include "kex.h"
87: #include "myproposal.h"
1.108 markus 88: #include "authfile.h"
1.154 markus 89: #include "pathnames.h"
1.155 markus 90: #include "atomicio.h"
91: #include "canohost.h"
1.343 deraadt 92: #include "hostfile.h"
1.155 markus 93: #include "auth.h"
1.404 markus 94: #include "authfd.h"
1.294 djm 95: #include "msg.h"
1.186 markus 96: #include "dispatch.h"
1.206 stevesk 97: #include "channels.h"
1.230 provos 98: #include "session.h"
1.231 provos 99: #include "monitor.h"
1.343 deraadt 100: #ifdef GSSAPI
101: #include "ssh-gss.h"
102: #endif
1.231 provos 103: #include "monitor_wrap.h"
1.385 djm 104: #include "ssh-sandbox.h"
1.332 stevesk 105: #include "version.h"
1.432 djm 106: #include "ssherr.h"
1.1 deraadt 107:
1.296 djm 108: /* Re-exec fds */
109: #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
110: #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
111: #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
112: #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
113:
1.138 markus 114: extern char *__progname;
115:
1.1 deraadt 116: /* Server configuration options. */
117: ServerOptions options;
118:
119: /* Name of the server configuration file. */
1.154 markus 120: char *config_file_name = _PATH_SERVER_CONFIG_FILE;
1.1 deraadt 121:
1.105 markus 122: /*
1.65 deraadt 123: * Debug mode flag. This can be set on the command line. If debug
124: * mode is enabled, extra debugging output will be sent to the system
125: * log, the daemon will not go to background, and will exit after processing
126: * the first connection.
127: */
1.1 deraadt 128: int debug_flag = 0;
129:
1.203 stevesk 130: /* Flag indicating that the daemon should only test the configuration and keys. */
131: int test_flag = 0;
132:
1.1 deraadt 133: /* Flag indicating that the daemon is being started from inetd. */
134: int inetd_flag = 0;
135:
1.135 markus 136: /* Flag indicating that sshd should not detach and become a daemon. */
137: int no_daemon_flag = 0;
138:
1.47 markus 139: /* debug goes to stderr unless inetd_flag is set */
140: int log_stderr = 0;
141:
1.1 deraadt 142: /* Saved arguments to main(). */
143: char **saved_argv;
144:
1.294 djm 145: /* re-exec */
146: int rexeced_flag = 0;
147: int rexec_flag = 1;
148: int rexec_argc = 0;
149: char **rexec_argv;
150:
1.66 markus 151: /*
1.75 markus 152: * The sockets that the server is listening; this is used in the SIGHUP
153: * signal handler.
1.66 markus 154: */
1.75 markus 155: #define MAX_LISTEN_SOCKS 16
156: int listen_socks[MAX_LISTEN_SOCKS];
157: int num_listen_socks = 0;
1.1 deraadt 158:
1.66 markus 159: /*
160: * the client's version string, passed by sshd2 in compat mode. if != NULL,
161: * sshd will skip the version-number exchange
162: */
1.61 markus 163: char *client_version_string = NULL;
1.96 markus 164: char *server_version_string = NULL;
1.1 deraadt 165:
1.404 markus 166: /* Daemon's agent connection */
1.432 djm 167: int auth_sock = -1;
1.404 markus 168: int have_agent = 0;
169:
1.66 markus 170: /*
171: * Any really sensitive data in the application is contained in this
172: * structure. The idea is that this structure could be locked into memory so
173: * that the pages do not get written into swap. However, there are some
174: * problems. The private key contains BIGNUMs, and we do not (in principle)
175: * have access to the internals of them, and locking just the structure is
176: * not very useful. Currently, memory locking is not implemented.
177: */
1.64 markus 178: struct {
1.134 markus 179: Key **host_keys; /* all private host keys */
1.404 markus 180: Key **host_pubkeys; /* all public host keys */
1.373 djm 181: Key **host_certificates; /* all public host certificates */
1.134 markus 182: int have_ssh2_key;
1.1 deraadt 183: } sensitive_data;
184:
1.199 markus 185: /* This is set to true when a signal is received. */
1.212 markus 186: static volatile sig_atomic_t received_sighup = 0;
187: static volatile sig_atomic_t received_sigterm = 0;
1.1 deraadt 188:
1.96 markus 189: /* session identifier, used by RSA-auth */
1.140 markus 190: u_char session_id[16];
1.96 markus 191:
1.108 markus 192: /* same for ssh2 */
1.140 markus 193: u_char *session_id2 = NULL;
1.269 markus 194: u_int session_id2_len = 0;
1.108 markus 195:
1.125 markus 196: /* record remote hostname or ip */
1.438 deraadt 197: u_int utmp_len = HOST_NAME_MAX+1;
1.125 markus 198:
1.211 markus 199: /* options.max_startup sized array of fd ints */
200: int *startup_pipes = NULL;
201: int startup_pipe; /* in child */
202:
1.231 provos 203: /* variables used for privilege separation */
1.337 dtucker 204: int use_privsep = -1;
1.285 dtucker 205: struct monitor *pmonitor = NULL;
1.386 djm 206: int privsep_is_preauth = 1;
1.231 provos 207:
1.278 markus 208: /* global authentication context */
209: Authctxt *the_authctxt = NULL;
210:
1.337 dtucker 211: /* sshd_config buffer */
212: Buffer cfg;
213:
1.299 dtucker 214: /* message to be displayed after login */
215: Buffer loginmsg;
216:
1.1 deraadt 217: /* Prototypes for various functions defined later in this file. */
1.200 itojun 218: void destroy_sensitive_data(void);
1.231 provos 219: void demote_sensitive_data(void);
1.200 itojun 220: static void do_ssh2_kex(void);
1.129 provos 221:
1.87 markus 222: /*
1.75 markus 223: * Close all listening sockets
224: */
1.200 itojun 225: static void
1.75 markus 226: close_listen_socks(void)
227: {
228: int i;
1.250 deraadt 229:
1.75 markus 230: for (i = 0; i < num_listen_socks; i++)
231: close(listen_socks[i]);
232: num_listen_socks = -1;
233: }
234:
1.211 markus 235: static void
236: close_startup_pipes(void)
237: {
238: int i;
1.250 deraadt 239:
1.211 markus 240: if (startup_pipes)
241: for (i = 0; i < options.max_startups; i++)
242: if (startup_pipes[i] != -1)
243: close(startup_pipes[i]);
244: }
245:
1.75 markus 246: /*
1.65 deraadt 247: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
248: * the effect is to reread the configuration file (and to regenerate
249: * the server key).
250: */
1.327 deraadt 251:
252: /*ARGSUSED*/
1.200 itojun 253: static void
1.64 markus 254: sighup_handler(int sig)
1.1 deraadt 255: {
1.210 deraadt 256: int save_errno = errno;
257:
1.64 markus 258: received_sighup = 1;
259: signal(SIGHUP, sighup_handler);
1.210 deraadt 260: errno = save_errno;
1.1 deraadt 261: }
262:
1.65 deraadt 263: /*
264: * Called from the main program after receiving SIGHUP.
265: * Restarts the server.
266: */
1.200 itojun 267: static void
1.165 itojun 268: sighup_restart(void)
1.1 deraadt 269: {
1.264 itojun 270: logit("Received SIGHUP; restarting.");
1.75 markus 271: close_listen_socks();
1.211 markus 272: close_startup_pipes();
1.349 dtucker 273: alarm(0); /* alarm timer persists across exec */
1.369 dtucker 274: signal(SIGHUP, SIG_IGN); /* will be restored after exec */
1.64 markus 275: execv(saved_argv[0], saved_argv);
1.264 itojun 276: logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
1.250 deraadt 277: strerror(errno));
1.64 markus 278: exit(1);
1.1 deraadt 279: }
280:
1.65 deraadt 281: /*
282: * Generic signal handler for terminating signals in the master daemon.
283: */
1.327 deraadt 284: /*ARGSUSED*/
1.200 itojun 285: static void
1.64 markus 286: sigterm_handler(int sig)
1.1 deraadt 287: {
1.199 markus 288: received_sigterm = sig;
1.1 deraadt 289: }
290:
1.65 deraadt 291: /*
292: * SIGCHLD handler. This is called whenever a child dies. This will then
1.199 markus 293: * reap any zombies left by exited children.
1.65 deraadt 294: */
1.327 deraadt 295: /*ARGSUSED*/
1.200 itojun 296: static void
1.64 markus 297: main_sigchld_handler(int sig)
1.1 deraadt 298: {
1.250 deraadt 299: int save_errno = errno;
1.239 markus 300: pid_t pid;
1.64 markus 301: int status;
1.60 deraadt 302:
1.239 markus 303: while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
304: (pid < 0 && errno == EINTR))
1.64 markus 305: ;
1.60 deraadt 306:
1.64 markus 307: signal(SIGCHLD, main_sigchld_handler);
308: errno = save_errno;
1.1 deraadt 309: }
310:
1.65 deraadt 311: /*
312: * Signal handler for the alarm after the login grace period has expired.
313: */
1.327 deraadt 314: /*ARGSUSED*/
1.200 itojun 315: static void
1.64 markus 316: grace_alarm_handler(int sig)
1.1 deraadt 317: {
1.285 dtucker 318: if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
319: kill(pmonitor->m_pid, SIGALRM);
1.394 djm 320:
321: /*
322: * Try to kill any processes that we have spawned, E.g. authorized
323: * keys command helpers.
324: */
325: if (getpgid(0) == getpid()) {
326: signal(SIGTERM, SIG_IGN);
1.416 djm 327: kill(0, SIGTERM);
1.394 djm 328: }
1.285 dtucker 329:
1.64 markus 330: /* Log error and exit. */
1.466 djm 331: sigdie("Timeout before authentication for %s port %d",
332: ssh_remote_ipaddr(active_state), ssh_remote_port(active_state));
1.62 markus 333: }
334:
1.200 itojun 335: static void
1.466 djm 336: sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out)
1.96 markus 337: {
1.311 djm 338: u_int i;
1.96 markus 339: int remote_major, remote_minor;
1.363 dtucker 340: char *s, *newline = "\n";
1.96 markus 341: char buf[256]; /* Must not be larger than remote_version. */
342: char remote_version[256]; /* Must be at least as big as buf. */
343:
1.390 djm 344: xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s",
1.473 naddy 345: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,
1.390 djm 346: *options.version_addendum == '\0' ? "" : " ",
347: options.version_addendum, newline);
1.96 markus 348:
1.272 markus 349: /* Send our protocol version identification. */
1.463 markus 350: if (atomicio(vwrite, sock_out, server_version_string,
1.272 markus 351: strlen(server_version_string))
352: != strlen(server_version_string)) {
1.466 djm 353: logit("Could not write ident string to %s port %d",
354: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 355: cleanup_exit(255);
1.272 markus 356: }
357:
358: /* Read other sides version identification. */
359: memset(buf, 0, sizeof(buf));
360: for (i = 0; i < sizeof(buf) - 1; i++) {
1.463 markus 361: if (atomicio(read, sock_in, &buf[i], 1) != 1) {
1.466 djm 362: logit("Did not receive identification string "
363: "from %s port %d",
364: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 365: cleanup_exit(255);
1.96 markus 366: }
1.272 markus 367: if (buf[i] == '\r') {
368: buf[i] = 0;
369: /* Kludge for F-Secure Macintosh < 1.0.2 */
370: if (i == 12 &&
371: strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
1.96 markus 372: break;
1.272 markus 373: continue;
374: }
375: if (buf[i] == '\n') {
376: buf[i] = 0;
377: break;
1.96 markus 378: }
379: }
1.272 markus 380: buf[sizeof(buf) - 1] = 0;
381: client_version_string = xstrdup(buf);
1.96 markus 382:
383: /*
384: * Check that the versions match. In future this might accept
385: * several versions and set appropriate flags to handle them.
386: */
387: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
388: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 389: s = "Protocol mismatch.\n";
1.271 deraadt 390: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.408 djm 391: logit("Bad protocol version identification '%.100s' "
392: "from %s port %d", client_version_string,
1.466 djm 393: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.411 djm 394: close(sock_in);
395: close(sock_out);
1.278 markus 396: cleanup_exit(255);
1.96 markus 397: }
398: debug("Client protocol version %d.%d; client software version %.100s",
1.217 deraadt 399: remote_major, remote_minor, remote_version);
1.96 markus 400:
1.466 djm 401: ssh->compat = compat_datafellows(remote_version);
1.260 mickey 402:
1.466 djm 403: if ((ssh->compat & SSH_BUG_PROBE) != 0) {
404: logit("probed from %s port %d with %s. Don't panic.",
405: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
406: client_version_string);
1.278 markus 407: cleanup_exit(255);
1.260 mickey 408: }
1.466 djm 409: if ((ssh->compat & SSH_BUG_SCANNER) != 0) {
410: logit("scanned from %s port %d with %s. Don't panic.",
411: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
412: client_version_string);
1.278 markus 413: cleanup_exit(255);
1.175 deraadt 414: }
1.466 djm 415: if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) {
1.413 djm 416: logit("Client version \"%.100s\" uses unsafe RSA signature "
417: "scheme; disabling use of RSA keys", remote_version);
1.414 djm 418: }
1.466 djm 419: if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) {
1.414 djm 420: fatal("Client version \"%.100s\" uses unsafe key agreement; "
421: "refusing connection", remote_version);
422: }
1.98 markus 423:
1.102 markus 424: chop(server_version_string);
425: debug("Local version string %.200s", server_version_string);
426:
1.472 markus 427: if (remote_major == 2 ||
428: (remote_major == 1 && remote_minor == 99)) {
429: enable_compat20();
430: } else {
1.96 markus 431: s = "Protocol major versions differ.\n";
1.271 deraadt 432: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.96 markus 433: close(sock_in);
434: close(sock_out);
1.466 djm 435: logit("Protocol major versions differ for %s port %d: "
436: "%.200s vs. %.200s",
437: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1.102 markus 438: server_version_string, client_version_string);
1.278 markus 439: cleanup_exit(255);
1.96 markus 440: }
1.108 markus 441: }
442:
1.134 markus 443: /* Destroy the host and server keys. They will no longer be needed. */
1.108 markus 444: void
445: destroy_sensitive_data(void)
446: {
1.134 markus 447: int i;
448:
1.217 deraadt 449: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 450: if (sensitive_data.host_keys[i]) {
451: key_free(sensitive_data.host_keys[i]);
452: sensitive_data.host_keys[i] = NULL;
453: }
1.373 djm 454: if (sensitive_data.host_certificates[i]) {
455: key_free(sensitive_data.host_certificates[i]);
456: sensitive_data.host_certificates[i] = NULL;
457: }
1.134 markus 458: }
459: }
460:
1.231 provos 461: /* Demote private to public keys for network child */
462: void
463: demote_sensitive_data(void)
464: {
465: Key *tmp;
466: int i;
467:
468: for (i = 0; i < options.num_host_key_files; i++) {
469: if (sensitive_data.host_keys[i]) {
470: tmp = key_demote(sensitive_data.host_keys[i]);
471: key_free(sensitive_data.host_keys[i]);
472: sensitive_data.host_keys[i] = tmp;
473: }
1.373 djm 474: /* Certs do not need demotion */
1.231 provos 475: }
476: }
477:
1.233 markus 478: static void
1.231 provos 479: privsep_preauth_child(void)
480: {
1.253 deraadt 481: gid_t gidset[1];
1.250 deraadt 482: struct passwd *pw;
1.231 provos 483:
484: /* Enable challenge-response authentication for privilege separation */
485: privsep_challenge_enable();
1.419 djm 486:
1.420 markus 487: #ifdef GSSAPI
1.419 djm 488: /* Cache supported mechanism OIDs for later use */
489: if (options.gss_authentication)
490: ssh_gssapi_prepare_supported_oids();
1.420 markus 491: #endif
1.231 provos 492:
493: /* Demote the private keys to public keys. */
494: demote_sensitive_data();
495:
1.460 djm 496: /* Demote the child */
497: if (getuid() == 0 || geteuid() == 0) {
498: if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
499: fatal("Privilege separation user %s does not exist",
500: SSH_PRIVSEP_USER);
501: explicit_bzero(pw->pw_passwd, strlen(pw->pw_passwd));
502: endpwent();
503:
504: /* Change our root directory */
505: if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
506: fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
507: strerror(errno));
508: if (chdir("/") == -1)
509: fatal("chdir(\"/\"): %s", strerror(errno));
510:
511: /*
512: * Drop our privileges
513: * NB. Can't use setusercontext() after chroot.
514: */
515: debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
516: (u_int)pw->pw_gid);
517: gidset[0] = pw->pw_gid;
518: if (setgroups(1, gidset) < 0)
519: fatal("setgroups: %.100s", strerror(errno));
520: permanently_set_uid(pw);
521: }
1.231 provos 522: }
523:
1.278 markus 524: static int
525: privsep_preauth(Authctxt *authctxt)
1.237 markus 526: {
1.432 djm 527: int status, r;
1.237 markus 528: pid_t pid;
1.384 djm 529: struct ssh_sandbox *box = NULL;
1.237 markus 530:
531: /* Set up unprivileged child process to deal with network data */
1.242 mouring 532: pmonitor = monitor_init();
1.237 markus 533: /* Store a pointer to the kex for later rekeying */
1.434 markus 534: pmonitor->m_pkex = &active_state->kex;
1.237 markus 535:
1.393 djm 536: if (use_privsep == PRIVSEP_ON)
1.384 djm 537: box = ssh_sandbox_init();
1.237 markus 538: pid = fork();
539: if (pid == -1) {
540: fatal("fork of unprivileged child failed");
541: } else if (pid != 0) {
1.245 mpech 542: debug2("Network child is on pid %ld", (long)pid);
1.237 markus 543:
1.392 markus 544: pmonitor->m_pid = pid;
1.432 djm 545: if (have_agent) {
546: r = ssh_get_authentication_socket(&auth_sock);
547: if (r != 0) {
548: error("Could not get agent socket: %s",
549: ssh_err(r));
550: have_agent = 0;
551: }
552: }
1.384 djm 553: if (box != NULL)
554: ssh_sandbox_parent_preauth(box, pid);
1.278 markus 555: monitor_child_preauth(authctxt, pmonitor);
1.237 markus 556:
557: /* Wait for the child's exit status */
1.384 djm 558: while (waitpid(pid, &status, 0) < 0) {
1.386 djm 559: if (errno == EINTR)
560: continue;
561: pmonitor->m_pid = -1;
562: fatal("%s: waitpid: %s", __func__, strerror(errno));
1.384 djm 563: }
1.386 djm 564: privsep_is_preauth = 0;
565: pmonitor->m_pid = -1;
1.384 djm 566: if (WIFEXITED(status)) {
567: if (WEXITSTATUS(status) != 0)
568: fatal("%s: preauth child exited with status %d",
569: __func__, WEXITSTATUS(status));
570: } else if (WIFSIGNALED(status))
571: fatal("%s: preauth child terminated by signal %d",
572: __func__, WTERMSIG(status));
573: if (box != NULL)
574: ssh_sandbox_parent_finish(box);
575: return 1;
1.237 markus 576: } else {
577: /* child */
1.383 djm 578: close(pmonitor->m_sendfd);
579: close(pmonitor->m_log_recvfd);
1.237 markus 580:
1.383 djm 581: /* Arrange for logging to be sent to the monitor */
582: set_log_handler(mm_log_handler, pmonitor);
1.237 markus 583:
1.460 djm 584: privsep_preauth_child();
1.238 stevesk 585: setproctitle("%s", "[net]");
1.384 djm 586: if (box != NULL)
587: ssh_sandbox_child(box);
588:
589: return 0;
1.237 markus 590: }
591: }
592:
1.233 markus 593: static void
1.237 markus 594: privsep_postauth(Authctxt *authctxt)
1.231 provos 595: {
1.474 djm 596: if (authctxt->pw->pw_uid == 0) {
1.231 provos 597: /* File descriptor passing is broken or root login */
598: use_privsep = 0;
1.315 djm 599: goto skip;
1.231 provos 600: }
1.234 markus 601:
1.231 provos 602: /* New socket pair */
1.242 mouring 603: monitor_reinit(pmonitor);
1.231 provos 604:
1.242 mouring 605: pmonitor->m_pid = fork();
606: if (pmonitor->m_pid == -1)
1.231 provos 607: fatal("fork of unprivileged child failed");
1.242 mouring 608: else if (pmonitor->m_pid != 0) {
1.364 markus 609: verbose("User child is on pid %ld", (long)pmonitor->m_pid);
1.307 otto 610: buffer_clear(&loginmsg);
1.242 mouring 611: monitor_child_postauth(pmonitor);
1.231 provos 612:
613: /* NEVERREACHED */
614: exit(0);
615: }
616:
1.383 djm 617: /* child */
618:
1.242 mouring 619: close(pmonitor->m_sendfd);
1.383 djm 620: pmonitor->m_sendfd = -1;
1.231 provos 621:
622: /* Demote the private keys to public keys. */
623: demote_sensitive_data();
1.354 djm 624:
1.231 provos 625: /* Drop privileges */
626: do_setusercontext(authctxt->pw);
627:
1.315 djm 628: skip:
1.231 provos 629: /* It is safe now to apply the key state */
1.242 mouring 630: monitor_apply_keystate(pmonitor);
1.312 markus 631:
632: /*
633: * Tell the packet layer that authentication was successful, since
634: * this information is not part of the key state.
635: */
636: packet_set_authenticated();
1.231 provos 637: }
638:
1.200 itojun 639: static char *
1.134 markus 640: list_hostkey_types(void)
641: {
1.223 markus 642: Buffer b;
1.281 jakob 643: const char *p;
644: char *ret;
1.134 markus 645: int i;
1.373 djm 646: Key *key;
1.223 markus 647:
648: buffer_init(&b);
1.217 deraadt 649: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 650: key = sensitive_data.host_keys[i];
1.443 djm 651: if (key == NULL)
1.404 markus 652: key = sensitive_data.host_pubkeys[i];
1.472 markus 653: if (key == NULL)
1.134 markus 654: continue;
1.454 markus 655: /* Check that the key is accepted in HostkeyAlgorithms */
656: if (match_pattern_list(sshkey_ssh_name(key),
657: options.hostkeyalgorithms, 0) != 1) {
658: debug3("%s: %s key not permitted by HostkeyAlgorithms",
659: __func__, sshkey_ssh_name(key));
660: continue;
661: }
1.214 deraadt 662: switch (key->type) {
1.134 markus 663: case KEY_RSA:
664: case KEY_DSA:
1.378 djm 665: case KEY_ECDSA:
1.412 markus 666: case KEY_ED25519:
1.223 markus 667: if (buffer_len(&b) > 0)
668: buffer_append(&b, ",", 1);
669: p = key_ssh_name(key);
670: buffer_append(&b, p, strlen(p));
1.461 markus 671:
672: /* for RSA we also support SHA2 signatures */
673: if (key->type == KEY_RSA) {
674: p = ",rsa-sha2-512,rsa-sha2-256";
675: buffer_append(&b, p, strlen(p));
676: }
1.134 markus 677: break;
678: }
1.373 djm 679: /* If the private key has a cert peer, then list that too */
680: key = sensitive_data.host_certificates[i];
681: if (key == NULL)
682: continue;
683: switch (key->type) {
684: case KEY_RSA_CERT:
685: case KEY_DSA_CERT:
1.378 djm 686: case KEY_ECDSA_CERT:
1.412 markus 687: case KEY_ED25519_CERT:
1.373 djm 688: if (buffer_len(&b) > 0)
689: buffer_append(&b, ",", 1);
690: p = key_ssh_name(key);
691: buffer_append(&b, p, strlen(p));
692: break;
693: }
1.134 markus 694: }
1.467 djm 695: if ((ret = sshbuf_dup_string(&b)) == NULL)
696: fatal("%s: sshbuf_dup_string failed", __func__);
1.223 markus 697: buffer_free(&b);
1.281 jakob 698: debug("list_hostkey_types: %s", ret);
699: return ret;
1.134 markus 700: }
701:
1.373 djm 702: static Key *
1.440 djm 703: get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
1.134 markus 704: {
705: int i;
1.373 djm 706: Key *key;
1.250 deraadt 707:
1.217 deraadt 708: for (i = 0; i < options.num_host_key_files; i++) {
1.375 djm 709: switch (type) {
710: case KEY_RSA_CERT:
711: case KEY_DSA_CERT:
1.378 djm 712: case KEY_ECDSA_CERT:
1.412 markus 713: case KEY_ED25519_CERT:
1.373 djm 714: key = sensitive_data.host_certificates[i];
1.375 djm 715: break;
716: default:
1.373 djm 717: key = sensitive_data.host_keys[i];
1.404 markus 718: if (key == NULL && !need_private)
719: key = sensitive_data.host_pubkeys[i];
1.375 djm 720: break;
721: }
1.440 djm 722: if (key != NULL && key->type == type &&
723: (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
1.373 djm 724: return need_private ?
725: sensitive_data.host_keys[i] : key;
1.134 markus 726: }
727: return NULL;
1.96 markus 728: }
729:
1.231 provos 730: Key *
1.440 djm 731: get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 732: {
1.440 djm 733: return get_hostkey_by_type(type, nid, 0, ssh);
1.373 djm 734: }
735:
736: Key *
1.440 djm 737: get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 738: {
1.440 djm 739: return get_hostkey_by_type(type, nid, 1, ssh);
1.373 djm 740: }
741:
742: Key *
1.231 provos 743: get_hostkey_by_index(int ind)
744: {
745: if (ind < 0 || ind >= options.num_host_key_files)
746: return (NULL);
747: return (sensitive_data.host_keys[ind]);
748: }
749:
1.404 markus 750: Key *
1.435 markus 751: get_hostkey_public_by_index(int ind, struct ssh *ssh)
1.404 markus 752: {
753: if (ind < 0 || ind >= options.num_host_key_files)
754: return (NULL);
755: return (sensitive_data.host_pubkeys[ind]);
756: }
757:
1.231 provos 758: int
1.442 djm 759: get_hostkey_index(Key *key, int compare, struct ssh *ssh)
1.231 provos 760: {
761: int i;
1.250 deraadt 762:
1.231 provos 763: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 764: if (key_is_cert(key)) {
1.442 djm 765: if (key == sensitive_data.host_certificates[i] ||
766: (compare && sensitive_data.host_certificates[i] &&
767: sshkey_equal(key,
768: sensitive_data.host_certificates[i])))
1.373 djm 769: return (i);
770: } else {
1.442 djm 771: if (key == sensitive_data.host_keys[i] ||
772: (compare && sensitive_data.host_keys[i] &&
773: sshkey_equal(key, sensitive_data.host_keys[i])))
1.373 djm 774: return (i);
1.442 djm 775: if (key == sensitive_data.host_pubkeys[i] ||
776: (compare && sensitive_data.host_pubkeys[i] &&
777: sshkey_equal(key, sensitive_data.host_pubkeys[i])))
1.404 markus 778: return (i);
1.373 djm 779: }
1.231 provos 780: }
781: return (-1);
782: }
783:
1.439 djm 784: /* Inform the client of all hostkeys */
785: static void
786: notify_hostkeys(struct ssh *ssh)
787: {
788: struct sshbuf *buf;
789: struct sshkey *key;
790: int i, nkeys, r;
791: char *fp;
1.446 dtucker 792:
793: /* Some clients cannot cope with the hostkeys message, skip those. */
794: if (datafellows & SSH_BUG_HOSTKEYS)
795: return;
1.439 djm 796:
797: if ((buf = sshbuf_new()) == NULL)
798: fatal("%s: sshbuf_new", __func__);
799: for (i = nkeys = 0; i < options.num_host_key_files; i++) {
800: key = get_hostkey_public_by_index(i, ssh);
801: if (key == NULL || key->type == KEY_UNSPEC ||
1.472 markus 802: sshkey_is_cert(key))
1.439 djm 803: continue;
804: fp = sshkey_fingerprint(key, options.fingerprint_hash,
805: SSH_FP_DEFAULT);
806: debug3("%s: key %d: %s %s", __func__, i,
807: sshkey_ssh_name(key), fp);
808: free(fp);
1.442 djm 809: if (nkeys == 0) {
810: packet_start(SSH2_MSG_GLOBAL_REQUEST);
1.444 djm 811: packet_put_cstring("hostkeys-00@openssh.com");
1.442 djm 812: packet_put_char(0); /* want-reply */
813: }
814: sshbuf_reset(buf);
815: if ((r = sshkey_putb(key, buf)) != 0)
1.439 djm 816: fatal("%s: couldn't put hostkey %d: %s",
817: __func__, i, ssh_err(r));
1.442 djm 818: packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
1.439 djm 819: nkeys++;
820: }
1.442 djm 821: debug3("%s: sent %d hostkeys", __func__, nkeys);
1.439 djm 822: if (nkeys == 0)
823: fatal("%s: no hostkeys", __func__);
824: packet_send();
1.442 djm 825: sshbuf_free(buf);
1.439 djm 826: }
827:
1.124 markus 828: /*
829: * returns 1 if connection should be dropped, 0 otherwise.
830: * dropping starts at connection #max_startups_begin with a probability
831: * of (max_startups_rate/100). the probability increases linearly until
832: * all connections are dropped for startups > max_startups
833: */
1.200 itojun 834: static int
1.124 markus 835: drop_connection(int startups)
836: {
1.303 mickey 837: int p, r;
1.124 markus 838:
839: if (startups < options.max_startups_begin)
840: return 0;
841: if (startups >= options.max_startups)
842: return 1;
843: if (options.max_startups_rate == 100)
844: return 1;
845:
846: p = 100 - options.max_startups_rate;
847: p *= startups - options.max_startups_begin;
1.303 mickey 848: p /= options.max_startups - options.max_startups_begin;
1.124 markus 849: p += options.max_startups_rate;
1.356 djm 850: r = arc4random_uniform(100);
1.124 markus 851:
1.304 djm 852: debug("drop_connection: p %d, r %d", p, r);
1.124 markus 853: return (r < p) ? 1 : 0;
854: }
855:
1.215 markus 856: static void
857: usage(void)
858: {
1.290 markus 859: fprintf(stderr, "%s, %s\n",
1.426 markus 860: SSH_VERSION,
861: #ifdef WITH_OPENSSL
862: SSLeay_version(SSLEAY_VERSION)
863: #else
864: "without OpenSSL"
865: #endif
866: );
1.289 markus 867: fprintf(stderr,
1.473 naddy 868: "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n"
1.399 dtucker 869: " [-E log_file] [-f config_file] [-g login_grace_time]\n"
1.473 naddy 870: " [-h host_key_file] [-o option] [-p port] [-u len]\n"
1.289 markus 871: );
1.215 markus 872: exit(1);
873: }
874:
1.294 djm 875: static void
1.467 djm 876: send_rexec_state(int fd, struct sshbuf *conf)
1.294 djm 877: {
1.467 djm 878: struct sshbuf *m;
879: int r;
1.294 djm 880:
1.467 djm 881: debug3("%s: entering fd = %d config len %zu", __func__, fd,
882: sshbuf_len(conf));
1.294 djm 883:
884: /*
885: * Protocol from reexec master to child:
886: * string configuration
887: */
1.467 djm 888: if ((m = sshbuf_new()) == NULL)
889: fatal("%s: sshbuf_new failed", __func__);
890: if ((r = sshbuf_put_stringb(m, conf)) != 0)
891: fatal("%s: buffer error: %s", __func__, ssh_err(r));
892: if (ssh_msg_send(fd, 0, m) == -1)
1.294 djm 893: fatal("%s: ssh_msg_send failed", __func__);
894:
1.467 djm 895: sshbuf_free(m);
1.294 djm 896:
897: debug3("%s: done", __func__);
898: }
899:
900: static void
901: recv_rexec_state(int fd, Buffer *conf)
902: {
903: Buffer m;
904: char *cp;
905: u_int len;
906:
907: debug3("%s: entering fd = %d", __func__, fd);
908:
909: buffer_init(&m);
910:
911: if (ssh_msg_recv(fd, &m) == -1)
912: fatal("%s: ssh_msg_recv failed", __func__);
913: if (buffer_get_char(&m) != 0)
914: fatal("%s: rexec version mismatch", __func__);
915:
916: cp = buffer_get_string(&m, &len);
917: if (conf != NULL)
1.469 djm 918: buffer_append(conf, cp, len);
1.402 djm 919: free(cp);
1.294 djm 920:
921: buffer_free(&m);
922:
923: debug3("%s: done", __func__);
924: }
925:
1.345 djm 926: /* Accept a connection from inetd */
927: static void
928: server_accept_inetd(int *sock_in, int *sock_out)
929: {
930: int fd;
931:
932: startup_pipe = -1;
933: if (rexeced_flag) {
934: close(REEXEC_CONFIG_PASS_FD);
935: *sock_in = *sock_out = dup(STDIN_FILENO);
936: if (!debug_flag) {
937: startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
938: close(REEXEC_STARTUP_PIPE_FD);
939: }
940: } else {
941: *sock_in = dup(STDIN_FILENO);
942: *sock_out = dup(STDOUT_FILENO);
943: }
944: /*
945: * We intentionally do not close the descriptors 0, 1, and 2
946: * as our code for setting the descriptors won't work if
947: * ttyfd happens to be one of those.
948: */
949: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
950: dup2(fd, STDIN_FILENO);
951: dup2(fd, STDOUT_FILENO);
1.403 dtucker 952: if (!log_stderr)
953: dup2(fd, STDERR_FILENO);
954: if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1.345 djm 955: close(fd);
956: }
957: debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
958: }
959:
960: /*
961: * Listen for TCP connections
962: */
963: static void
964: server_listen(void)
965: {
966: int ret, listen_sock, on = 1;
967: struct addrinfo *ai;
968: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
969:
970: for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
971: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
972: continue;
973: if (num_listen_socks >= MAX_LISTEN_SOCKS)
974: fatal("Too many listen sockets. "
975: "Enlarge MAX_LISTEN_SOCKS");
976: if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
977: ntop, sizeof(ntop), strport, sizeof(strport),
978: NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
979: error("getnameinfo failed: %.100s",
1.352 dtucker 980: ssh_gai_strerror(ret));
1.345 djm 981: continue;
982: }
983: /* Create socket for listening. */
1.370 dtucker 984: listen_sock = socket(ai->ai_family, ai->ai_socktype,
985: ai->ai_protocol);
1.345 djm 986: if (listen_sock < 0) {
987: /* kernel may not support ipv6 */
988: verbose("socket: %.100s", strerror(errno));
989: continue;
990: }
991: if (set_nonblock(listen_sock) == -1) {
992: close(listen_sock);
993: continue;
994: }
995: /*
996: * Set socket options.
997: * Allow local port reuse in TIME_WAIT.
998: */
999: if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1000: &on, sizeof(on)) == -1)
1001: error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1002:
1003: debug("Bind to port %s on %s.", strport, ntop);
1004:
1005: /* Bind the socket to the desired port. */
1006: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1007: error("Bind to port %s on %s failed: %.200s.",
1008: strport, ntop, strerror(errno));
1009: close(listen_sock);
1010: continue;
1011: }
1012: listen_socks[num_listen_socks] = listen_sock;
1013: num_listen_socks++;
1014:
1015: /* Start listening on the port. */
1016: if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1017: fatal("listen on [%s]:%s: %.100s",
1018: ntop, strport, strerror(errno));
1019: logit("Server listening on %s port %s.", ntop, strport);
1020: }
1021: freeaddrinfo(options.listen_addrs);
1022:
1023: if (!num_listen_socks)
1024: fatal("Cannot bind any address.");
1025: }
1026:
1027: /*
1028: * The main TCP accept loop. Note that, for the non-debug case, returns
1029: * from this function are in a forked subprocess.
1030: */
1031: static void
1032: server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1033: {
1034: fd_set *fdset;
1035: int i, j, ret, maxfd;
1.472 markus 1036: int startups = 0;
1.345 djm 1037: int startup_p[2] = { -1 , -1 };
1038: struct sockaddr_storage from;
1039: socklen_t fromlen;
1040: pid_t pid;
1041:
1042: /* setup fd set for accept */
1043: fdset = NULL;
1044: maxfd = 0;
1045: for (i = 0; i < num_listen_socks; i++)
1046: if (listen_socks[i] > maxfd)
1047: maxfd = listen_socks[i];
1048: /* pipes connected to unauthenticated childs */
1049: startup_pipes = xcalloc(options.max_startups, sizeof(int));
1050: for (i = 0; i < options.max_startups; i++)
1051: startup_pipes[i] = -1;
1052:
1053: /*
1054: * Stay listening for connections until the system crashes or
1055: * the daemon is killed with a signal.
1056: */
1057: for (;;) {
1058: if (received_sighup)
1059: sighup_restart();
1.462 mmcc 1060: free(fdset);
1.458 deraadt 1061: fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1.345 djm 1062: sizeof(fd_mask));
1063:
1064: for (i = 0; i < num_listen_socks; i++)
1065: FD_SET(listen_socks[i], fdset);
1066: for (i = 0; i < options.max_startups; i++)
1067: if (startup_pipes[i] != -1)
1068: FD_SET(startup_pipes[i], fdset);
1069:
1070: /* Wait in select until there is a connection. */
1071: ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1072: if (ret < 0 && errno != EINTR)
1073: error("select: %.100s", strerror(errno));
1074: if (received_sigterm) {
1075: logit("Received signal %d; terminating.",
1076: (int) received_sigterm);
1077: close_listen_socks();
1.430 djm 1078: if (options.pid_file != NULL)
1079: unlink(options.pid_file);
1.382 djm 1080: exit(received_sigterm == SIGTERM ? 0 : 255);
1.345 djm 1081: }
1082: if (ret < 0)
1083: continue;
1084:
1085: for (i = 0; i < options.max_startups; i++)
1086: if (startup_pipes[i] != -1 &&
1087: FD_ISSET(startup_pipes[i], fdset)) {
1088: /*
1089: * the read end of the pipe is ready
1090: * if the child has closed the pipe
1091: * after successful authentication
1092: * or if the child has died
1093: */
1094: close(startup_pipes[i]);
1095: startup_pipes[i] = -1;
1096: startups--;
1097: }
1098: for (i = 0; i < num_listen_socks; i++) {
1099: if (!FD_ISSET(listen_socks[i], fdset))
1100: continue;
1101: fromlen = sizeof(from);
1102: *newsock = accept(listen_socks[i],
1103: (struct sockaddr *)&from, &fromlen);
1104: if (*newsock < 0) {
1.398 markus 1105: if (errno != EINTR && errno != EWOULDBLOCK &&
1106: errno != ECONNABORTED)
1.389 djm 1107: error("accept: %.100s",
1108: strerror(errno));
1109: if (errno == EMFILE || errno == ENFILE)
1110: usleep(100 * 1000);
1.345 djm 1111: continue;
1112: }
1113: if (unset_nonblock(*newsock) == -1) {
1114: close(*newsock);
1115: continue;
1116: }
1117: if (drop_connection(startups) == 1) {
1118: debug("drop connection #%d", startups);
1119: close(*newsock);
1120: continue;
1121: }
1122: if (pipe(startup_p) == -1) {
1123: close(*newsock);
1124: continue;
1125: }
1126:
1127: if (rexec_flag && socketpair(AF_UNIX,
1128: SOCK_STREAM, 0, config_s) == -1) {
1129: error("reexec socketpair: %s",
1130: strerror(errno));
1131: close(*newsock);
1132: close(startup_p[0]);
1133: close(startup_p[1]);
1134: continue;
1135: }
1136:
1137: for (j = 0; j < options.max_startups; j++)
1138: if (startup_pipes[j] == -1) {
1139: startup_pipes[j] = startup_p[0];
1140: if (maxfd < startup_p[0])
1141: maxfd = startup_p[0];
1142: startups++;
1143: break;
1144: }
1145:
1146: /*
1147: * Got connection. Fork a child to handle it, unless
1148: * we are in debugging mode.
1149: */
1150: if (debug_flag) {
1151: /*
1152: * In debugging mode. Close the listening
1153: * socket, and start processing the
1154: * connection without forking.
1155: */
1156: debug("Server will not fork when running in debugging mode.");
1157: close_listen_socks();
1158: *sock_in = *newsock;
1159: *sock_out = *newsock;
1160: close(startup_p[0]);
1161: close(startup_p[1]);
1162: startup_pipe = -1;
1163: pid = getpid();
1164: if (rexec_flag) {
1165: send_rexec_state(config_s[0],
1166: &cfg);
1167: close(config_s[0]);
1168: }
1169: break;
1170: }
1171:
1172: /*
1173: * Normal production daemon. Fork, and have
1174: * the child process the connection. The
1175: * parent continues listening.
1176: */
1177: if ((pid = fork()) == 0) {
1178: /*
1179: * Child. Close the listening and
1180: * max_startup sockets. Start using
1181: * the accepted socket. Reinitialize
1182: * logging (since our pid has changed).
1183: * We break out of the loop to handle
1184: * the connection.
1185: */
1186: startup_pipe = startup_p[1];
1187: close_startup_pipes();
1188: close_listen_socks();
1189: *sock_in = *newsock;
1190: *sock_out = *newsock;
1191: log_init(__progname,
1192: options.log_level,
1193: options.log_facility,
1194: log_stderr);
1195: if (rexec_flag)
1196: close(config_s[0]);
1197: break;
1198: }
1199:
1200: /* Parent. Stay in the loop. */
1201: if (pid < 0)
1202: error("fork: %.100s", strerror(errno));
1203: else
1204: debug("Forked child %ld.", (long)pid);
1205:
1206: close(startup_p[1]);
1207:
1208: if (rexec_flag) {
1209: send_rexec_state(config_s[0], &cfg);
1210: close(config_s[0]);
1211: close(config_s[1]);
1212: }
1213: close(*newsock);
1214: }
1215:
1216: /* child process check (or debug mode) */
1217: if (num_listen_socks < 0)
1218: break;
1219: }
1220: }
1221:
1.466 djm 1222: /*
1223: * If IP options are supported, make sure there are none (log and
1224: * return an error if any are found). Basically we are worried about
1225: * source routing; it can be used to pretend you are somebody
1226: * (ip-address) you are not. That itself may be "almost acceptable"
1227: * under certain circumstances, but rhosts autentication is useless
1228: * if source routing is accepted. Notice also that if we just dropped
1229: * source routing here, the other side could use IP spoofing to do
1230: * rest of the interaction and could still bypass security. So we
1231: * exit here if we detect any IP options.
1232: */
1233: static void
1234: check_ip_options(struct ssh *ssh)
1235: {
1236: int sock_in = ssh_packet_get_connection_in(ssh);
1237: struct sockaddr_storage from;
1238: u_char opts[200];
1.475 djm 1239: socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
1.466 djm 1240: char text[sizeof(opts) * 3 + 1];
1241:
1242: memset(&from, 0, sizeof(from));
1243: if (getpeername(sock_in, (struct sockaddr *)&from,
1244: &fromlen) < 0)
1245: return;
1246: if (from.ss_family != AF_INET)
1247: return;
1248: /* XXX IPv6 options? */
1249:
1250: if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
1251: &option_size) >= 0 && option_size != 0) {
1252: text[0] = '\0';
1253: for (i = 0; i < option_size; i++)
1254: snprintf(text + i*3, sizeof(text) - i*3,
1255: " %2.2x", opts[i]);
1256: fatal("Connection from %.100s port %d with IP opts: %.800s",
1257: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
1258: }
1259: return;
1260: }
1.345 djm 1261:
1.65 deraadt 1262: /*
1263: * Main program for the daemon.
1264: */
1.2 provos 1265: int
1266: main(int ac, char **av)
1.1 deraadt 1267: {
1.466 djm 1268: struct ssh *ssh = NULL;
1.64 markus 1269: extern char *optarg;
1270: extern int optind;
1.432 djm 1271: int r, opt, i, j, on = 1;
1.297 avsm 1272: int sock_in = -1, sock_out = -1, newsock = -1;
1.64 markus 1273: const char *remote_ip;
1274: int remote_port;
1.447 dtucker 1275: char *fp, *line, *laddr, *logfile = NULL;
1.345 djm 1276: int config_s[2] = { -1 , -1 };
1.396 djm 1277: u_int n;
1.364 markus 1278: u_int64_t ibytes, obytes;
1.362 dtucker 1279: mode_t new_umask;
1.278 markus 1280: Key *key;
1.404 markus 1281: Key *pubkey;
1282: int keytype;
1.230 provos 1283: Authctxt *authctxt;
1.391 dtucker 1284: struct connection_info *connection_info = get_connection_info(0, 0);
1.64 markus 1285:
1.465 dtucker 1286: ssh_malloc_init(); /* must be called before any mallocs */
1.138 markus 1287: /* Save argv. */
1.64 markus 1288: saved_argv = av;
1.294 djm 1289: rexec_argc = ac;
1.313 djm 1290:
1291: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1292: sanitise_stdfd();
1.64 markus 1293:
1294: /* Initialize configuration options to their default values. */
1295: initialize_server_options(&options);
1296:
1297: /* Parse command-line arguments. */
1.450 djm 1298: while ((opt = getopt(ac, av,
1299: "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1.64 markus 1300: switch (opt) {
1.75 markus 1301: case '4':
1.305 djm 1302: options.address_family = AF_INET;
1.75 markus 1303: break;
1304: case '6':
1.305 djm 1305: options.address_family = AF_INET6;
1.75 markus 1306: break;
1.64 markus 1307: case 'f':
1308: config_file_name = optarg;
1309: break;
1.373 djm 1310: case 'c':
1311: if (options.num_host_cert_files >= MAX_HOSTCERTS) {
1312: fprintf(stderr, "too many host certificates.\n");
1313: exit(1);
1314: }
1315: options.host_cert_files[options.num_host_cert_files++] =
1316: derelativise_path(optarg);
1317: break;
1.64 markus 1318: case 'd':
1.273 markus 1319: if (debug_flag == 0) {
1.127 markus 1320: debug_flag = 1;
1321: options.log_level = SYSLOG_LEVEL_DEBUG1;
1.273 markus 1322: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1.127 markus 1323: options.log_level++;
1.64 markus 1324: break;
1.135 markus 1325: case 'D':
1326: no_daemon_flag = 1;
1.192 lebel 1327: break;
1.399 dtucker 1328: case 'E':
1.459 dtucker 1329: logfile = optarg;
1.399 dtucker 1330: /* FALLTHROUGH */
1.192 lebel 1331: case 'e':
1332: log_stderr = 1;
1.135 markus 1333: break;
1.64 markus 1334: case 'i':
1335: inetd_flag = 1;
1336: break;
1.294 djm 1337: case 'r':
1338: rexec_flag = 0;
1339: break;
1340: case 'R':
1341: rexeced_flag = 1;
1342: inetd_flag = 1;
1343: break;
1.64 markus 1344: case 'Q':
1.158 markus 1345: /* ignored */
1.64 markus 1346: break;
1347: case 'q':
1348: options.log_level = SYSLOG_LEVEL_QUIET;
1349: break;
1350: case 'b':
1.473 naddy 1351: /* protocol 1, ignored */
1.64 markus 1352: break;
1353: case 'p':
1.75 markus 1354: options.ports_from_cmdline = 1;
1.127 markus 1355: if (options.num_ports >= MAX_PORTS) {
1356: fprintf(stderr, "too many ports.\n");
1357: exit(1);
1358: }
1.193 stevesk 1359: options.ports[options.num_ports++] = a2port(optarg);
1.366 djm 1360: if (options.ports[options.num_ports-1] <= 0) {
1.193 stevesk 1361: fprintf(stderr, "Bad port number.\n");
1362: exit(1);
1363: }
1.64 markus 1364: break;
1365: case 'g':
1.197 stevesk 1366: if ((options.login_grace_time = convtime(optarg)) == -1) {
1367: fprintf(stderr, "Invalid login grace time.\n");
1368: exit(1);
1369: }
1.64 markus 1370: break;
1371: case 'k':
1.473 naddy 1372: /* protocol 1, ignored */
1.64 markus 1373: break;
1374: case 'h':
1.134 markus 1375: if (options.num_host_key_files >= MAX_HOSTKEYS) {
1376: fprintf(stderr, "too many host keys.\n");
1377: exit(1);
1378: }
1.371 djm 1379: options.host_key_files[options.num_host_key_files++] =
1380: derelativise_path(optarg);
1.64 markus 1381: break;
1.203 stevesk 1382: case 't':
1383: test_flag = 1;
1384: break;
1.358 dtucker 1385: case 'T':
1386: test_flag = 2;
1387: break;
1388: case 'C':
1.391 dtucker 1389: if (parse_server_match_testspec(connection_info,
1390: optarg) == -1)
1391: exit(1);
1.358 dtucker 1392: break;
1.125 markus 1393: case 'u':
1.438 deraadt 1394: utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1395: if (utmp_len > HOST_NAME_MAX+1) {
1.257 stevesk 1396: fprintf(stderr, "Invalid utmp length.\n");
1397: exit(1);
1398: }
1.125 markus 1399: break;
1.215 markus 1400: case 'o':
1.283 markus 1401: line = xstrdup(optarg);
1402: if (process_server_config_line(&options, line,
1.391 dtucker 1403: "command-line", 0, NULL, NULL) != 0)
1.217 deraadt 1404: exit(1);
1.402 djm 1405: free(line);
1.215 markus 1406: break;
1.64 markus 1407: case '?':
1408: default:
1.215 markus 1409: usage();
1410: break;
1.64 markus 1411: }
1412: }
1.294 djm 1413: if (rexeced_flag || inetd_flag)
1414: rexec_flag = 0;
1.355 mbalmer 1415: if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1.294 djm 1416: fatal("sshd re-exec requires execution with an absolute path");
1417: if (rexeced_flag)
1.296 djm 1418: closefrom(REEXEC_MIN_FREE_FD);
1419: else
1420: closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1.294 djm 1421:
1.426 markus 1422: #ifdef WITH_OPENSSL
1.379 djm 1423: OpenSSL_add_all_algorithms();
1.426 markus 1424: #endif
1.64 markus 1425:
1.399 dtucker 1426: /* If requested, redirect the logs to the specified logfile. */
1.459 dtucker 1427: if (logfile != NULL)
1.399 dtucker 1428: log_redirect_stderr_to(logfile);
1.75 markus 1429: /*
1430: * Force logging to stderr until we have loaded the private host
1431: * key (unless started from inetd)
1432: */
1.138 markus 1433: log_init(__progname,
1.224 markus 1434: options.log_level == SYSLOG_LEVEL_NOT_SET ?
1435: SYSLOG_LEVEL_INFO : options.log_level,
1436: options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1437: SYSLOG_FACILITY_AUTH : options.log_facility,
1.261 markus 1438: log_stderr || !inetd_flag);
1.75 markus 1439:
1.294 djm 1440: sensitive_data.have_ssh2_key = 0;
1441:
1.358 dtucker 1442: /*
1443: * If we're doing an extended config test, make sure we have all of
1444: * the parameters we need. If we're not doing an extended test,
1445: * do not silently ignore connection test params.
1446: */
1.391 dtucker 1447: if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0)
1.358 dtucker 1448: fatal("user, host and addr are all required when testing "
1449: "Match configs");
1.391 dtucker 1450: if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0)
1.358 dtucker 1451: fatal("Config test connection parameter (-C) provided without "
1452: "test mode (-T)");
1453:
1.294 djm 1454: /* Fetch our configuration */
1455: buffer_init(&cfg);
1456: if (rexeced_flag)
1.296 djm 1457: recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
1.448 djm 1458: else if (strcasecmp(config_file_name, "none") != 0)
1.294 djm 1459: load_server_config(config_file_name, &cfg);
1460:
1.337 dtucker 1461: parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1.391 dtucker 1462: &cfg, NULL);
1.64 markus 1463:
1464: /* Fill in default values for those options not explicitly set. */
1465: fill_default_server_options(&options);
1.350 dtucker 1466:
1467: /* challenge-response is implemented via keyboard interactive */
1468: if (options.challenge_response_authentication)
1469: options.kbd_interactive_authentication = 1;
1.395 djm 1470:
1471: /* Check that options are sensible */
1472: if (options.authorized_keys_command_user == NULL &&
1473: (options.authorized_keys_command != NULL &&
1474: strcasecmp(options.authorized_keys_command, "none") != 0))
1475: fatal("AuthorizedKeysCommand set without "
1476: "AuthorizedKeysCommandUser");
1.449 djm 1477: if (options.authorized_principals_command_user == NULL &&
1478: (options.authorized_principals_command != NULL &&
1479: strcasecmp(options.authorized_principals_command, "none") != 0))
1480: fatal("AuthorizedPrincipalsCommand set without "
1481: "AuthorizedPrincipalsCommandUser");
1.396 djm 1482:
1483: /*
1484: * Check whether there is any path through configured auth methods.
1485: * Unfortunately it is not possible to verify this generally before
1486: * daemonisation in the presence of Match block, but this catches
1487: * and warns for trivial misconfigurations that could break login.
1488: */
1489: if (options.num_auth_methods != 0) {
1490: for (n = 0; n < options.num_auth_methods; n++) {
1491: if (auth2_methods_valid(options.auth_methods[n],
1492: 1) == 0)
1493: break;
1494: }
1495: if (n >= options.num_auth_methods)
1496: fatal("AuthenticationMethods cannot be satisfied by "
1497: "enabled authentication methods");
1498: }
1.305 djm 1499:
1.370 dtucker 1500: /* set default channel AF */
1.305 djm 1501: channel_set_af(options.address_family);
1.64 markus 1502:
1503: /* Check that there are no remaining arguments. */
1504: if (optind < ac) {
1505: fprintf(stderr, "Extra argument %s.\n", av[optind]);
1506: exit(1);
1507: }
1508:
1.397 dtucker 1509: debug("sshd version %s, %s", SSH_VERSION,
1.426 markus 1510: #ifdef WITH_OPENSSL
1511: SSLeay_version(SSLEAY_VERSION)
1512: #else
1513: "without OpenSSL"
1514: #endif
1515: );
1.64 markus 1516:
1.404 markus 1517: /* load host keys */
1.329 djm 1518: sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1.255 deraadt 1519: sizeof(Key *));
1.404 markus 1520: sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1521: sizeof(Key *));
1522:
1523: if (options.host_key_agent) {
1524: if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1525: setenv(SSH_AUTHSOCKET_ENV_NAME,
1526: options.host_key_agent, 1);
1.433 djm 1527: if ((r = ssh_get_authentication_socket(NULL)) == 0)
1528: have_agent = 1;
1529: else
1530: error("Could not connect to agent \"%s\": %s",
1531: options.host_key_agent, ssh_err(r));
1.404 markus 1532: }
1.134 markus 1533:
1.217 deraadt 1534: for (i = 0; i < options.num_host_key_files; i++) {
1.430 djm 1535: if (options.host_key_files[i] == NULL)
1536: continue;
1.179 markus 1537: key = key_load_private(options.host_key_files[i], "", NULL);
1.404 markus 1538: pubkey = key_load_public(options.host_key_files[i], NULL);
1.439 djm 1539: if (pubkey == NULL && key != NULL)
1540: pubkey = key_demote(key);
1.179 markus 1541: sensitive_data.host_keys[i] = key;
1.404 markus 1542: sensitive_data.host_pubkeys[i] = pubkey;
1543:
1.472 markus 1544: if (key == NULL && pubkey != NULL && have_agent) {
1.443 djm 1545: debug("will rely on agent for hostkey %s",
1546: options.host_key_files[i]);
1.404 markus 1547: keytype = pubkey->type;
1548: } else if (key != NULL) {
1549: keytype = key->type;
1550: } else {
1.195 markus 1551: error("Could not load host key: %s",
1552: options.host_key_files[i]);
1.179 markus 1553: sensitive_data.host_keys[i] = NULL;
1.404 markus 1554: sensitive_data.host_pubkeys[i] = NULL;
1.134 markus 1555: continue;
1556: }
1.404 markus 1557:
1558: switch (keytype) {
1.134 markus 1559: case KEY_RSA:
1560: case KEY_DSA:
1.378 djm 1561: case KEY_ECDSA:
1.412 markus 1562: case KEY_ED25519:
1.441 djm 1563: if (have_agent || key != NULL)
1564: sensitive_data.have_ssh2_key = 1;
1.134 markus 1565: break;
1566: }
1.441 djm 1567: if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1568: SSH_FP_DEFAULT)) == NULL)
1569: fatal("sshkey_fingerprint failed");
1570: debug("%s host key #%d: %s %s",
1.472 markus 1571: key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp);
1.441 djm 1572: free(fp);
1.134 markus 1573: }
1.472 markus 1574: if (!sensitive_data.have_ssh2_key) {
1.264 itojun 1575: logit("sshd: no hostkeys available -- exiting.");
1.64 markus 1576: exit(1);
1577: }
1578:
1.373 djm 1579: /*
1580: * Load certificates. They are stored in an array at identical
1581: * indices to the public keys that they relate to.
1582: */
1583: sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1584: sizeof(Key *));
1585: for (i = 0; i < options.num_host_key_files; i++)
1586: sensitive_data.host_certificates[i] = NULL;
1587:
1588: for (i = 0; i < options.num_host_cert_files; i++) {
1.430 djm 1589: if (options.host_cert_files[i] == NULL)
1590: continue;
1.373 djm 1591: key = key_load_public(options.host_cert_files[i], NULL);
1592: if (key == NULL) {
1593: error("Could not load host certificate: %s",
1594: options.host_cert_files[i]);
1595: continue;
1596: }
1597: if (!key_is_cert(key)) {
1598: error("Certificate file is not a certificate: %s",
1599: options.host_cert_files[i]);
1600: key_free(key);
1601: continue;
1602: }
1603: /* Find matching private key */
1604: for (j = 0; j < options.num_host_key_files; j++) {
1605: if (key_equal_public(key,
1606: sensitive_data.host_keys[j])) {
1607: sensitive_data.host_certificates[j] = key;
1608: break;
1609: }
1610: }
1611: if (j >= options.num_host_key_files) {
1612: error("No matching private key for certificate: %s",
1613: options.host_cert_files[i]);
1614: key_free(key);
1615: continue;
1616: }
1617: sensitive_data.host_certificates[j] = key;
1618: debug("host certificate: #%d type %d %s", j, key->type,
1619: key_type(key));
1620: }
1.426 markus 1621:
1.244 markus 1622: if (use_privsep) {
1623: struct stat st;
1624:
1.327 deraadt 1625: if (getpwnam(SSH_PRIVSEP_USER) == NULL)
1.244 markus 1626: fatal("Privilege separation user %s does not exist",
1627: SSH_PRIVSEP_USER);
1628: if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1629: (S_ISDIR(st.st_mode) == 0))
1630: fatal("Missing privilege separation directory: %s",
1.247 stevesk 1631: _PATH_PRIVSEP_CHROOT_DIR);
1632: if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1.262 markus 1633: fatal("%s must be owned by root and not group or "
1634: "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1.358 dtucker 1635: }
1636:
1637: if (test_flag > 1) {
1.391 dtucker 1638: if (server_match_spec_complete(connection_info) == 1)
1639: parse_server_match_config(&options, connection_info);
1.358 dtucker 1640: dump_config(&options);
1.108 markus 1641: }
1.203 stevesk 1642:
1643: /* Configuration looks good, so exit if in test mode. */
1644: if (test_flag)
1645: exit(0);
1.108 markus 1646:
1.294 djm 1647: if (rexec_flag) {
1.329 djm 1648: rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1.294 djm 1649: for (i = 0; i < rexec_argc; i++) {
1650: debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1651: rexec_argv[i] = saved_argv[i];
1652: }
1653: rexec_argv[rexec_argc] = "-R";
1654: rexec_argv[rexec_argc + 1] = NULL;
1655: }
1.362 dtucker 1656:
1657: /* Ensure that umask disallows at least group and world write */
1658: new_umask = umask(0077) | 0022;
1659: (void) umask(new_umask);
1.294 djm 1660:
1.108 markus 1661: /* Initialize the log (it is reinitialized below in case we forked). */
1.306 dtucker 1662: if (debug_flag && (!inetd_flag || rexeced_flag))
1.64 markus 1663: log_stderr = 1;
1.138 markus 1664: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1665:
1.108 markus 1666: /*
1667: * If not in debugging mode, and not started from inetd, disconnect
1668: * from the controlling terminal, and fork. The original process
1669: * exits.
1670: */
1.135 markus 1671: if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1.345 djm 1672:
1.64 markus 1673: if (daemon(0, 0) < 0)
1674: fatal("daemon() failed: %.200s", strerror(errno));
1675:
1.477 ! dtucker 1676: disconnect_controlling_tty();
1.64 markus 1677: }
1678: /* Reinitialize the log (because of the fork above). */
1.138 markus 1679: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1680:
1681: /* Chdir to the root directory so that the current disk can be
1682: unmounted if desired. */
1.401 dtucker 1683: if (chdir("/") == -1)
1684: error("chdir(\"/\"): %s", strerror(errno));
1.217 deraadt 1685:
1.178 markus 1686: /* ignore SIGPIPE */
1687: signal(SIGPIPE, SIG_IGN);
1.64 markus 1688:
1.345 djm 1689: /* Get a connection, either from inetd or a listening TCP socket */
1.64 markus 1690: if (inetd_flag) {
1.345 djm 1691: server_accept_inetd(&sock_in, &sock_out);
1.64 markus 1692: } else {
1.345 djm 1693: server_listen();
1.75 markus 1694:
1.201 markus 1695: signal(SIGHUP, sighup_handler);
1.345 djm 1696: signal(SIGCHLD, main_sigchld_handler);
1.201 markus 1697: signal(SIGTERM, sigterm_handler);
1698: signal(SIGQUIT, sigterm_handler);
1699:
1.345 djm 1700: /*
1701: * Write out the pid file after the sigterm handler
1702: * is setup and the listen sockets are bound
1703: */
1.430 djm 1704: if (options.pid_file != NULL && !debug_flag) {
1.345 djm 1705: FILE *f = fopen(options.pid_file, "w");
1.201 markus 1706:
1.270 djm 1707: if (f == NULL) {
1708: error("Couldn't create pid file \"%s\": %s",
1709: options.pid_file, strerror(errno));
1710: } else {
1.245 mpech 1711: fprintf(f, "%ld\n", (long) getpid());
1.64 markus 1712: fclose(f);
1713: }
1714: }
1715:
1.345 djm 1716: /* Accept a connection and return in a forked child */
1717: server_accept_loop(&sock_in, &sock_out,
1718: &newsock, config_s);
1.1 deraadt 1719: }
1720:
1.64 markus 1721: /* This is the child processing a new connection. */
1.288 markus 1722: setproctitle("%s", "[accepted]");
1.294 djm 1723:
1.300 markus 1724: /*
1725: * Create a new session and process group since the 4.4BSD
1726: * setlogin() affects the entire process group. We don't
1727: * want the child to be able to affect the parent.
1728: */
1729: if (!debug_flag && !inetd_flag && setsid() < 0)
1730: error("setsid: %.100s", strerror(errno));
1731:
1.294 djm 1732: if (rexec_flag) {
1733: int fd;
1734:
1.296 djm 1735: debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1736: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1737: dup2(newsock, STDIN_FILENO);
1738: dup2(STDIN_FILENO, STDOUT_FILENO);
1739: if (startup_pipe == -1)
1.296 djm 1740: close(REEXEC_STARTUP_PIPE_FD);
1.407 djm 1741: else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
1.296 djm 1742: dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
1.407 djm 1743: close(startup_pipe);
1744: startup_pipe = REEXEC_STARTUP_PIPE_FD;
1745: }
1.294 djm 1746:
1.296 djm 1747: dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
1.294 djm 1748: close(config_s[1]);
1.296 djm 1749:
1.294 djm 1750: execv(rexec_argv[0], rexec_argv);
1751:
1752: /* Reexec has failed, fall back and continue */
1753: error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
1.296 djm 1754: recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
1.294 djm 1755: log_init(__progname, options.log_level,
1756: options.log_facility, log_stderr);
1757:
1758: /* Clean up fds */
1.296 djm 1759: close(REEXEC_CONFIG_PASS_FD);
1760: newsock = sock_out = sock_in = dup(STDIN_FILENO);
1.294 djm 1761: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1762: dup2(fd, STDIN_FILENO);
1763: dup2(fd, STDOUT_FILENO);
1764: if (fd > STDERR_FILENO)
1765: close(fd);
1766: }
1.296 djm 1767: debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1768: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1769: }
1.372 djm 1770:
1771: /* Executed child processes don't need these. */
1772: fcntl(sock_out, F_SETFD, FD_CLOEXEC);
1773: fcntl(sock_in, F_SETFD, FD_CLOEXEC);
1.64 markus 1774:
1.66 markus 1775: /*
1776: * Disable the key regeneration alarm. We will not regenerate the
1777: * key since we are no longer in a position to give it to anyone. We
1778: * will not restart on SIGHUP since it no longer makes sense.
1779: */
1.64 markus 1780: alarm(0);
1781: signal(SIGALRM, SIG_DFL);
1782: signal(SIGHUP, SIG_DFL);
1783: signal(SIGTERM, SIG_DFL);
1784: signal(SIGQUIT, SIG_DFL);
1785: signal(SIGCHLD, SIG_DFL);
1.150 markus 1786:
1.66 markus 1787: /*
1788: * Register our connection. This turns encryption off because we do
1789: * not have a key.
1790: */
1.64 markus 1791: packet_set_connection(sock_in, sock_out);
1.312 markus 1792: packet_set_server();
1.466 djm 1793: ssh = active_state; /* XXX */
1794: check_ip_options(ssh);
1.309 djm 1795:
1796: /* Set SO_KEEPALIVE if requested. */
1797: if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1798: setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1799: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.1 deraadt 1800:
1.466 djm 1801: if ((remote_port = ssh_remote_port(ssh)) < 0) {
1802: debug("ssh_remote_port failed");
1.310 markus 1803: cleanup_exit(255);
1804: }
1.316 dtucker 1805:
1806: /*
1.331 markus 1807: * The rest of the code depends on the fact that
1.466 djm 1808: * ssh_remote_ipaddr() caches the remote ip, even if
1.331 markus 1809: * the socket goes away.
1810: */
1.466 djm 1811: remote_ip = ssh_remote_ipaddr(ssh);
1.209 markus 1812:
1.64 markus 1813: /* Log the connection. */
1.447 dtucker 1814: laddr = get_local_ipaddr(sock_in);
1.409 djm 1815: verbose("Connection from %s port %d on %s port %d",
1.466 djm 1816: remote_ip, remote_port, laddr, ssh_local_port(ssh));
1.447 dtucker 1817: free(laddr);
1.1 deraadt 1818:
1.66 markus 1819: /*
1.317 djm 1820: * We don't want to listen forever unless the other side
1.66 markus 1821: * successfully authenticates itself. So we set up an alarm which is
1822: * cleared after successful authentication. A limit of zero
1.317 djm 1823: * indicates no limit. Note that we don't set the alarm in debugging
1.66 markus 1824: * mode; it is just annoying to have the server exit just when you
1825: * are about to discover the bug.
1826: */
1.64 markus 1827: signal(SIGALRM, grace_alarm_handler);
1828: if (!debug_flag)
1829: alarm(options.login_grace_time);
1830:
1.466 djm 1831: sshd_exchange_identification(ssh, sock_in, sock_out);
1.64 markus 1832: packet_set_nonblocking();
1.1 deraadt 1833:
1.278 markus 1834: /* allocate authentication context */
1.329 djm 1835: authctxt = xcalloc(1, sizeof(*authctxt));
1.278 markus 1836:
1837: /* XXX global for cleanup, access from other modules */
1838: the_authctxt = authctxt;
1839:
1.307 otto 1840: /* prepare buffer to collect messages to display to user after login */
1841: buffer_init(&loginmsg);
1.374 dtucker 1842: auth_debug_reset();
1.307 otto 1843:
1.404 markus 1844: if (use_privsep) {
1.278 markus 1845: if (privsep_preauth(authctxt) == 1)
1.237 markus 1846: goto authenticated;
1.472 markus 1847: } else if (have_agent) {
1.432 djm 1848: if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
1849: error("Unable to get agent socket: %s", ssh_err(r));
1.433 djm 1850: have_agent = 0;
1.432 djm 1851: }
1852: }
1.231 provos 1853:
1.77 markus 1854: /* perform the key exchange */
1855: /* authenticate user and start session */
1.472 markus 1856: do_ssh2_kex();
1857: do_authentication2(authctxt);
1858:
1.237 markus 1859: /*
1860: * If we use privilege separation, the unprivileged child transfers
1861: * the current keystate and exits
1862: */
1863: if (use_privsep) {
1.242 mouring 1864: mm_send_keystate(pmonitor);
1.231 provos 1865: exit(0);
1.237 markus 1866: }
1.231 provos 1867:
1868: authenticated:
1.318 djm 1869: /*
1870: * Cancel the alarm we set to limit the time taken for
1871: * authentication.
1872: */
1873: alarm(0);
1874: signal(SIGALRM, SIG_DFL);
1.347 markus 1875: authctxt->authenticated = 1;
1.318 djm 1876: if (startup_pipe != -1) {
1877: close(startup_pipe);
1878: startup_pipe = -1;
1879: }
1880:
1.234 markus 1881: /*
1.231 provos 1882: * In privilege separation, we fork another child and prepare
1883: * file descriptor passing.
1884: */
1885: if (use_privsep) {
1.237 markus 1886: privsep_postauth(authctxt);
1887: /* the monitor process [priv] will not return */
1.231 provos 1888: }
1.360 dtucker 1889:
1890: packet_set_timeout(options.client_alive_interval,
1891: options.client_alive_count_max);
1.439 djm 1892:
1893: /* Try to send all our hostkeys to the client */
1.472 markus 1894: notify_hostkeys(active_state);
1.230 provos 1895:
1.278 markus 1896: /* Start session. */
1.230 provos 1897: do_authenticated(authctxt);
1898:
1.64 markus 1899: /* The connection has been terminated. */
1.434 markus 1900: packet_get_bytes(&ibytes, &obytes);
1.381 djm 1901: verbose("Transferred: sent %llu, received %llu bytes",
1902: (unsigned long long)obytes, (unsigned long long)ibytes);
1.364 markus 1903:
1904: verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
1.64 markus 1905: packet_close();
1.231 provos 1906:
1907: if (use_privsep)
1908: mm_terminate();
1909:
1.64 markus 1910: exit(0);
1.1 deraadt 1911: }
1.98 markus 1912:
1.435 markus 1913: int
1914: sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen,
1.461 markus 1915: const u_char *data, size_t dlen, const char *alg, u_int flag)
1.404 markus 1916: {
1.432 djm 1917: int r;
1.435 markus 1918: u_int xxx_slen, xxx_dlen = dlen;
1.432 djm 1919:
1.404 markus 1920: if (privkey) {
1.461 markus 1921: if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen,
1922: alg) < 0))
1.404 markus 1923: fatal("%s: key_sign failed", __func__);
1.435 markus 1924: if (slen)
1925: *slen = xxx_slen;
1.404 markus 1926: } else if (use_privsep) {
1.461 markus 1927: if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen,
1928: alg) < 0)
1.404 markus 1929: fatal("%s: pubkey_sign failed", __func__);
1.435 markus 1930: if (slen)
1931: *slen = xxx_slen;
1.404 markus 1932: } else {
1.435 markus 1933: if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
1.461 markus 1934: data, dlen, alg, datafellows)) != 0)
1.432 djm 1935: fatal("%s: ssh_agent_sign failed: %s",
1936: __func__, ssh_err(r));
1.404 markus 1937: }
1.435 markus 1938: return 0;
1.404 markus 1939: }
1940:
1.452 djm 1941: /* SSH2 key exchange */
1.200 itojun 1942: static void
1.142 markus 1943: do_ssh2_kex(void)
1.98 markus 1944: {
1.422 markus 1945: char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
1.435 markus 1946: struct kex *kex;
1.437 markus 1947: int r;
1.102 markus 1948:
1.457 djm 1949: myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
1950: options.kex_algorithms);
1951: myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
1952: options.ciphers);
1953: myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
1954: options.ciphers);
1955: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1956: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1957:
1.312 markus 1958: if (options.compression == COMP_NONE) {
1.246 markus 1959: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.470 dtucker 1960: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.102 markus 1961: }
1.400 dtucker 1962:
1963: if (options.rekey_limit || options.rekey_interval)
1.464 dtucker 1964: packet_set_rekey_limits(options.rekey_limit,
1.400 dtucker 1965: (time_t)options.rekey_interval);
1.327 deraadt 1966:
1.413 djm 1967: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
1968: list_hostkey_types());
1.134 markus 1969:
1.189 markus 1970: /* start key exchange */
1.437 markus 1971: if ((r = kex_setup(active_state, myproposal)) != 0)
1972: fatal("kex_setup: %s", ssh_err(r));
1.435 markus 1973: kex = active_state->kex;
1.426 markus 1974: #ifdef WITH_OPENSSL
1.263 markus 1975: kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1.292 djm 1976: kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1.468 djm 1977: kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server;
1978: kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server;
1979: kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server;
1.263 markus 1980: kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1.324 djm 1981: kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1.378 djm 1982: kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1.426 markus 1983: #endif
1.410 markus 1984: kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1.186 markus 1985: kex->server = 1;
1986: kex->client_version_string=client_version_string;
1987: kex->server_version_string=server_version_string;
1.373 djm 1988: kex->load_host_public_key=&get_hostkey_public_by_type;
1989: kex->load_host_private_key=&get_hostkey_private_by_type;
1.231 provos 1990: kex->host_key_index=&get_hostkey_index;
1.404 markus 1991: kex->sign = sshd_hostkey_sign;
1.189 markus 1992:
1.435 markus 1993: dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
1.187 markus 1994:
1995: session_id2 = kex->session_id;
1996: session_id2_len = kex->session_id_len;
1.129 provos 1997:
1998: #ifdef DEBUG_KEXDH
1999: /* send 1st encrypted/maced/compressed message */
2000: packet_start(SSH2_MSG_IGNORE);
2001: packet_put_cstring("markus");
2002: packet_send();
2003: packet_write_wait();
2004: #endif
1.186 markus 2005: debug("KEX done");
1.278 markus 2006: }
2007:
2008: /* server specific fatal cleanup */
2009: void
2010: cleanup_exit(int i)
2011: {
1.386 djm 2012: if (the_authctxt) {
1.278 markus 2013: do_cleanup(the_authctxt);
1.423 djm 2014: if (use_privsep && privsep_is_preauth &&
2015: pmonitor != NULL && pmonitor->m_pid > 1) {
1.386 djm 2016: debug("Killing privsep child %d", pmonitor->m_pid);
2017: if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
1.388 djm 2018: errno != ESRCH)
1.386 djm 2019: error("%s: kill(%d): %s", __func__,
2020: pmonitor->m_pid, strerror(errno));
2021: }
2022: }
1.278 markus 2023: _exit(i);
1.1 deraadt 2024: }
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