Annotation of src/usr.bin/ssh/sshd.c, Revision 1.500
1.500 ! djm 1: /* $OpenBSD: sshd.c,v 1.499 2017/11/14 00:45:29 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"
1.171 djm 73: #include "sshpty.h"
1.1 deraadt 74: #include "packet.h"
1.155 markus 75: #include "log.h"
1.343 deraadt 76: #include "buffer.h"
1.428 millert 77: #include "misc.h"
1.454 markus 78: #include "match.h"
1.1 deraadt 79: #include "servconf.h"
80: #include "uidswap.h"
1.33 markus 81: #include "compat.h"
1.155 markus 82: #include "cipher.h"
1.415 markus 83: #include "digest.h"
1.343 deraadt 84: #include "key.h"
1.98 markus 85: #include "kex.h"
86: #include "myproposal.h"
1.108 markus 87: #include "authfile.h"
1.154 markus 88: #include "pathnames.h"
1.155 markus 89: #include "atomicio.h"
90: #include "canohost.h"
1.343 deraadt 91: #include "hostfile.h"
1.155 markus 92: #include "auth.h"
1.404 markus 93: #include "authfd.h"
1.294 djm 94: #include "msg.h"
1.186 markus 95: #include "dispatch.h"
1.206 stevesk 96: #include "channels.h"
1.230 provos 97: #include "session.h"
1.231 provos 98: #include "monitor.h"
1.343 deraadt 99: #ifdef GSSAPI
100: #include "ssh-gss.h"
101: #endif
1.231 provos 102: #include "monitor_wrap.h"
1.385 djm 103: #include "ssh-sandbox.h"
1.332 stevesk 104: #include "version.h"
1.432 djm 105: #include "ssherr.h"
1.1 deraadt 106:
1.296 djm 107: /* Re-exec fds */
108: #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
109: #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
110: #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
111: #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
112:
1.138 markus 113: extern char *__progname;
114:
1.1 deraadt 115: /* Server configuration options. */
116: ServerOptions options;
117:
118: /* Name of the server configuration file. */
1.154 markus 119: char *config_file_name = _PATH_SERVER_CONFIG_FILE;
1.1 deraadt 120:
1.105 markus 121: /*
1.65 deraadt 122: * Debug mode flag. This can be set on the command line. If debug
123: * mode is enabled, extra debugging output will be sent to the system
124: * log, the daemon will not go to background, and will exit after processing
125: * the first connection.
126: */
1.1 deraadt 127: int debug_flag = 0;
128:
1.499 djm 129: /*
130: * Indicating that the daemon should only test the configuration and keys.
131: * If test_flag > 1 ("-T" flag), then sshd will also dump the effective
132: * configuration, optionally using connection information provided by the
133: * "-C" flag.
134: */
1.203 stevesk 135: int test_flag = 0;
136:
1.1 deraadt 137: /* Flag indicating that the daemon is being started from inetd. */
138: int inetd_flag = 0;
139:
1.135 markus 140: /* Flag indicating that sshd should not detach and become a daemon. */
141: int no_daemon_flag = 0;
142:
1.47 markus 143: /* debug goes to stderr unless inetd_flag is set */
144: int log_stderr = 0;
145:
1.1 deraadt 146: /* Saved arguments to main(). */
147: char **saved_argv;
148:
1.294 djm 149: /* re-exec */
150: int rexeced_flag = 0;
151: int rexec_flag = 1;
152: int rexec_argc = 0;
153: char **rexec_argv;
154:
1.66 markus 155: /*
1.75 markus 156: * The sockets that the server is listening; this is used in the SIGHUP
157: * signal handler.
1.66 markus 158: */
1.75 markus 159: #define MAX_LISTEN_SOCKS 16
160: int listen_socks[MAX_LISTEN_SOCKS];
161: int num_listen_socks = 0;
1.1 deraadt 162:
1.66 markus 163: /*
164: * the client's version string, passed by sshd2 in compat mode. if != NULL,
165: * sshd will skip the version-number exchange
166: */
1.61 markus 167: char *client_version_string = NULL;
1.96 markus 168: char *server_version_string = NULL;
1.1 deraadt 169:
1.404 markus 170: /* Daemon's agent connection */
1.432 djm 171: int auth_sock = -1;
1.404 markus 172: int have_agent = 0;
173:
1.66 markus 174: /*
175: * Any really sensitive data in the application is contained in this
176: * structure. The idea is that this structure could be locked into memory so
177: * that the pages do not get written into swap. However, there are some
178: * problems. The private key contains BIGNUMs, and we do not (in principle)
179: * have access to the internals of them, and locking just the structure is
180: * not very useful. Currently, memory locking is not implemented.
181: */
1.64 markus 182: struct {
1.488 markus 183: struct sshkey **host_keys; /* all private host keys */
184: struct sshkey **host_pubkeys; /* all public host keys */
185: struct sshkey **host_certificates; /* all public host certificates */
186: int have_ssh2_key;
1.1 deraadt 187: } sensitive_data;
188:
1.199 markus 189: /* This is set to true when a signal is received. */
1.212 markus 190: static volatile sig_atomic_t received_sighup = 0;
191: static volatile sig_atomic_t received_sigterm = 0;
1.1 deraadt 192:
1.96 markus 193: /* session identifier, used by RSA-auth */
1.140 markus 194: u_char session_id[16];
1.96 markus 195:
1.108 markus 196: /* same for ssh2 */
1.140 markus 197: u_char *session_id2 = NULL;
1.269 markus 198: u_int session_id2_len = 0;
1.108 markus 199:
1.125 markus 200: /* record remote hostname or ip */
1.438 deraadt 201: u_int utmp_len = HOST_NAME_MAX+1;
1.125 markus 202:
1.211 markus 203: /* options.max_startup sized array of fd ints */
204: int *startup_pipes = NULL;
205: int startup_pipe; /* in child */
206:
1.231 provos 207: /* variables used for privilege separation */
1.337 dtucker 208: int use_privsep = -1;
1.285 dtucker 209: struct monitor *pmonitor = NULL;
1.386 djm 210: int privsep_is_preauth = 1;
1.231 provos 211:
1.278 markus 212: /* global authentication context */
213: Authctxt *the_authctxt = NULL;
214:
1.337 dtucker 215: /* sshd_config buffer */
216: Buffer cfg;
217:
1.299 dtucker 218: /* message to be displayed after login */
219: Buffer loginmsg;
220:
1.1 deraadt 221: /* Prototypes for various functions defined later in this file. */
1.200 itojun 222: void destroy_sensitive_data(void);
1.231 provos 223: void demote_sensitive_data(void);
1.200 itojun 224: static void do_ssh2_kex(void);
1.129 provos 225:
1.87 markus 226: /*
1.75 markus 227: * Close all listening sockets
228: */
1.200 itojun 229: static void
1.75 markus 230: close_listen_socks(void)
231: {
232: int i;
1.250 deraadt 233:
1.75 markus 234: for (i = 0; i < num_listen_socks; i++)
235: close(listen_socks[i]);
236: num_listen_socks = -1;
237: }
238:
1.211 markus 239: static void
240: close_startup_pipes(void)
241: {
242: int i;
1.250 deraadt 243:
1.211 markus 244: if (startup_pipes)
245: for (i = 0; i < options.max_startups; i++)
246: if (startup_pipes[i] != -1)
247: close(startup_pipes[i]);
248: }
249:
1.75 markus 250: /*
1.65 deraadt 251: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
252: * the effect is to reread the configuration file (and to regenerate
253: * the server key).
254: */
1.327 deraadt 255:
256: /*ARGSUSED*/
1.200 itojun 257: static void
1.64 markus 258: sighup_handler(int sig)
1.1 deraadt 259: {
1.210 deraadt 260: int save_errno = errno;
261:
1.64 markus 262: received_sighup = 1;
263: signal(SIGHUP, sighup_handler);
1.210 deraadt 264: errno = save_errno;
1.1 deraadt 265: }
266:
1.65 deraadt 267: /*
268: * Called from the main program after receiving SIGHUP.
269: * Restarts the server.
270: */
1.200 itojun 271: static void
1.165 itojun 272: sighup_restart(void)
1.1 deraadt 273: {
1.264 itojun 274: logit("Received SIGHUP; restarting.");
1.479 dtucker 275: if (options.pid_file != NULL)
276: unlink(options.pid_file);
1.75 markus 277: close_listen_socks();
1.211 markus 278: close_startup_pipes();
1.349 dtucker 279: alarm(0); /* alarm timer persists across exec */
1.369 dtucker 280: signal(SIGHUP, SIG_IGN); /* will be restored after exec */
1.64 markus 281: execv(saved_argv[0], saved_argv);
1.264 itojun 282: logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
1.250 deraadt 283: strerror(errno));
1.64 markus 284: exit(1);
1.1 deraadt 285: }
286:
1.65 deraadt 287: /*
288: * Generic signal handler for terminating signals in the master daemon.
289: */
1.327 deraadt 290: /*ARGSUSED*/
1.200 itojun 291: static void
1.64 markus 292: sigterm_handler(int sig)
1.1 deraadt 293: {
1.199 markus 294: received_sigterm = sig;
1.1 deraadt 295: }
296:
1.65 deraadt 297: /*
298: * SIGCHLD handler. This is called whenever a child dies. This will then
1.199 markus 299: * reap any zombies left by exited children.
1.65 deraadt 300: */
1.327 deraadt 301: /*ARGSUSED*/
1.200 itojun 302: static void
1.64 markus 303: main_sigchld_handler(int sig)
1.1 deraadt 304: {
1.250 deraadt 305: int save_errno = errno;
1.239 markus 306: pid_t pid;
1.64 markus 307: int status;
1.60 deraadt 308:
1.239 markus 309: while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
310: (pid < 0 && errno == EINTR))
1.64 markus 311: ;
1.60 deraadt 312:
1.64 markus 313: signal(SIGCHLD, main_sigchld_handler);
314: errno = save_errno;
1.1 deraadt 315: }
316:
1.65 deraadt 317: /*
318: * Signal handler for the alarm after the login grace period has expired.
319: */
1.327 deraadt 320: /*ARGSUSED*/
1.200 itojun 321: static void
1.64 markus 322: grace_alarm_handler(int sig)
1.1 deraadt 323: {
1.285 dtucker 324: if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
325: kill(pmonitor->m_pid, SIGALRM);
1.394 djm 326:
327: /*
328: * Try to kill any processes that we have spawned, E.g. authorized
329: * keys command helpers.
330: */
331: if (getpgid(0) == getpid()) {
332: signal(SIGTERM, SIG_IGN);
1.416 djm 333: kill(0, SIGTERM);
1.394 djm 334: }
1.285 dtucker 335:
1.64 markus 336: /* Log error and exit. */
1.466 djm 337: sigdie("Timeout before authentication for %s port %d",
338: ssh_remote_ipaddr(active_state), ssh_remote_port(active_state));
1.62 markus 339: }
340:
1.200 itojun 341: static void
1.466 djm 342: sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out)
1.96 markus 343: {
1.311 djm 344: u_int i;
1.96 markus 345: int remote_major, remote_minor;
1.482 djm 346: char *s;
1.96 markus 347: char buf[256]; /* Must not be larger than remote_version. */
348: char remote_version[256]; /* Must be at least as big as buf. */
349:
1.482 djm 350: xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s\r\n",
1.473 naddy 351: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,
1.390 djm 352: *options.version_addendum == '\0' ? "" : " ",
1.482 djm 353: options.version_addendum);
1.96 markus 354:
1.272 markus 355: /* Send our protocol version identification. */
1.463 markus 356: if (atomicio(vwrite, sock_out, server_version_string,
1.272 markus 357: strlen(server_version_string))
358: != strlen(server_version_string)) {
1.466 djm 359: logit("Could not write ident string to %s port %d",
360: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 361: cleanup_exit(255);
1.272 markus 362: }
363:
364: /* Read other sides version identification. */
365: memset(buf, 0, sizeof(buf));
366: for (i = 0; i < sizeof(buf) - 1; i++) {
1.463 markus 367: if (atomicio(read, sock_in, &buf[i], 1) != 1) {
1.466 djm 368: logit("Did not receive identification string "
369: "from %s port %d",
370: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 371: cleanup_exit(255);
1.96 markus 372: }
1.272 markus 373: if (buf[i] == '\r') {
374: buf[i] = 0;
375: /* Kludge for F-Secure Macintosh < 1.0.2 */
376: if (i == 12 &&
377: strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
1.96 markus 378: break;
1.272 markus 379: continue;
380: }
381: if (buf[i] == '\n') {
382: buf[i] = 0;
383: break;
1.96 markus 384: }
385: }
1.272 markus 386: buf[sizeof(buf) - 1] = 0;
387: client_version_string = xstrdup(buf);
1.96 markus 388:
389: /*
390: * Check that the versions match. In future this might accept
391: * several versions and set appropriate flags to handle them.
392: */
393: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
394: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 395: s = "Protocol mismatch.\n";
1.271 deraadt 396: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.408 djm 397: logit("Bad protocol version identification '%.100s' "
398: "from %s port %d", client_version_string,
1.466 djm 399: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.411 djm 400: close(sock_in);
401: close(sock_out);
1.278 markus 402: cleanup_exit(255);
1.96 markus 403: }
404: debug("Client protocol version %d.%d; client software version %.100s",
1.217 deraadt 405: remote_major, remote_minor, remote_version);
1.96 markus 406:
1.466 djm 407: ssh->compat = compat_datafellows(remote_version);
1.260 mickey 408:
1.466 djm 409: if ((ssh->compat & SSH_BUG_PROBE) != 0) {
410: logit("probed 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);
1.260 mickey 414: }
1.466 djm 415: if ((ssh->compat & SSH_BUG_SCANNER) != 0) {
416: logit("scanned from %s port %d with %s. Don't panic.",
417: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
418: client_version_string);
1.278 markus 419: cleanup_exit(255);
1.175 deraadt 420: }
1.466 djm 421: if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) {
1.413 djm 422: logit("Client version \"%.100s\" uses unsafe RSA signature "
423: "scheme; disabling use of RSA keys", remote_version);
1.414 djm 424: }
1.466 djm 425: if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) {
1.414 djm 426: fatal("Client version \"%.100s\" uses unsafe key agreement; "
427: "refusing connection", remote_version);
428: }
1.98 markus 429:
1.102 markus 430: chop(server_version_string);
431: debug("Local version string %.200s", server_version_string);
432:
1.486 djm 433: if (remote_major != 2 ||
434: (remote_major == 1 && remote_minor != 99)) {
1.96 markus 435: s = "Protocol major versions differ.\n";
1.271 deraadt 436: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.96 markus 437: close(sock_in);
438: close(sock_out);
1.466 djm 439: logit("Protocol major versions differ for %s port %d: "
440: "%.200s vs. %.200s",
441: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1.102 markus 442: server_version_string, client_version_string);
1.278 markus 443: cleanup_exit(255);
1.96 markus 444: }
1.108 markus 445: }
446:
1.134 markus 447: /* Destroy the host and server keys. They will no longer be needed. */
1.108 markus 448: void
449: destroy_sensitive_data(void)
450: {
1.493 djm 451: u_int i;
1.134 markus 452:
1.217 deraadt 453: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 454: if (sensitive_data.host_keys[i]) {
455: key_free(sensitive_data.host_keys[i]);
456: sensitive_data.host_keys[i] = NULL;
457: }
1.373 djm 458: if (sensitive_data.host_certificates[i]) {
459: key_free(sensitive_data.host_certificates[i]);
460: sensitive_data.host_certificates[i] = NULL;
461: }
1.134 markus 462: }
463: }
464:
1.231 provos 465: /* Demote private to public keys for network child */
466: void
467: demote_sensitive_data(void)
468: {
1.488 markus 469: struct sshkey *tmp;
1.493 djm 470: u_int i;
1.231 provos 471:
472: for (i = 0; i < options.num_host_key_files; i++) {
473: if (sensitive_data.host_keys[i]) {
474: tmp = key_demote(sensitive_data.host_keys[i]);
475: key_free(sensitive_data.host_keys[i]);
476: sensitive_data.host_keys[i] = tmp;
477: }
1.373 djm 478: /* Certs do not need demotion */
1.231 provos 479: }
480: }
481:
1.233 markus 482: static void
1.231 provos 483: privsep_preauth_child(void)
484: {
1.253 deraadt 485: gid_t gidset[1];
1.250 deraadt 486: struct passwd *pw;
1.231 provos 487:
488: /* Enable challenge-response authentication for privilege separation */
489: privsep_challenge_enable();
1.419 djm 490:
1.420 markus 491: #ifdef GSSAPI
1.419 djm 492: /* Cache supported mechanism OIDs for later use */
493: if (options.gss_authentication)
494: ssh_gssapi_prepare_supported_oids();
1.420 markus 495: #endif
1.231 provos 496:
497: /* Demote the private keys to public keys. */
498: demote_sensitive_data();
499:
1.460 djm 500: /* Demote the child */
501: if (getuid() == 0 || geteuid() == 0) {
502: if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
503: fatal("Privilege separation user %s does not exist",
504: SSH_PRIVSEP_USER);
1.500 ! djm 505: pw = pwcopy(pw); /* Ensure mutable */
1.460 djm 506: endpwent();
1.500 ! djm 507: freezero(pw->pw_passwd, strlen(pw->pw_passwd));
1.460 djm 508:
509: /* Change our root directory */
510: if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
511: fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
512: strerror(errno));
513: if (chdir("/") == -1)
514: fatal("chdir(\"/\"): %s", strerror(errno));
515:
516: /*
517: * Drop our privileges
518: * NB. Can't use setusercontext() after chroot.
519: */
520: debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
521: (u_int)pw->pw_gid);
522: gidset[0] = pw->pw_gid;
523: if (setgroups(1, gidset) < 0)
524: fatal("setgroups: %.100s", strerror(errno));
525: permanently_set_uid(pw);
526: }
1.231 provos 527: }
528:
1.278 markus 529: static int
530: privsep_preauth(Authctxt *authctxt)
1.237 markus 531: {
1.432 djm 532: int status, r;
1.237 markus 533: pid_t pid;
1.384 djm 534: struct ssh_sandbox *box = NULL;
1.237 markus 535:
536: /* Set up unprivileged child process to deal with network data */
1.242 mouring 537: pmonitor = monitor_init();
1.237 markus 538: /* Store a pointer to the kex for later rekeying */
1.434 markus 539: pmonitor->m_pkex = &active_state->kex;
1.237 markus 540:
1.393 djm 541: if (use_privsep == PRIVSEP_ON)
1.384 djm 542: box = ssh_sandbox_init();
1.237 markus 543: pid = fork();
544: if (pid == -1) {
545: fatal("fork of unprivileged child failed");
546: } else if (pid != 0) {
1.245 mpech 547: debug2("Network child is on pid %ld", (long)pid);
1.237 markus 548:
1.392 markus 549: pmonitor->m_pid = pid;
1.432 djm 550: if (have_agent) {
551: r = ssh_get_authentication_socket(&auth_sock);
552: if (r != 0) {
553: error("Could not get agent socket: %s",
554: ssh_err(r));
555: have_agent = 0;
556: }
557: }
1.384 djm 558: if (box != NULL)
559: ssh_sandbox_parent_preauth(box, pid);
1.278 markus 560: monitor_child_preauth(authctxt, pmonitor);
1.237 markus 561:
562: /* Wait for the child's exit status */
1.384 djm 563: while (waitpid(pid, &status, 0) < 0) {
1.386 djm 564: if (errno == EINTR)
565: continue;
566: pmonitor->m_pid = -1;
567: fatal("%s: waitpid: %s", __func__, strerror(errno));
1.384 djm 568: }
1.386 djm 569: privsep_is_preauth = 0;
570: pmonitor->m_pid = -1;
1.384 djm 571: if (WIFEXITED(status)) {
572: if (WEXITSTATUS(status) != 0)
573: fatal("%s: preauth child exited with status %d",
574: __func__, WEXITSTATUS(status));
575: } else if (WIFSIGNALED(status))
576: fatal("%s: preauth child terminated by signal %d",
577: __func__, WTERMSIG(status));
578: if (box != NULL)
579: ssh_sandbox_parent_finish(box);
580: return 1;
1.237 markus 581: } else {
582: /* child */
1.383 djm 583: close(pmonitor->m_sendfd);
584: close(pmonitor->m_log_recvfd);
1.237 markus 585:
1.383 djm 586: /* Arrange for logging to be sent to the monitor */
587: set_log_handler(mm_log_handler, pmonitor);
1.237 markus 588:
1.460 djm 589: privsep_preauth_child();
1.238 stevesk 590: setproctitle("%s", "[net]");
1.384 djm 591: if (box != NULL)
592: ssh_sandbox_child(box);
593:
594: return 0;
1.237 markus 595: }
596: }
597:
1.233 markus 598: static void
1.237 markus 599: privsep_postauth(Authctxt *authctxt)
1.231 provos 600: {
1.474 djm 601: if (authctxt->pw->pw_uid == 0) {
1.231 provos 602: /* File descriptor passing is broken or root login */
603: use_privsep = 0;
1.315 djm 604: goto skip;
1.231 provos 605: }
1.234 markus 606:
1.231 provos 607: /* New socket pair */
1.242 mouring 608: monitor_reinit(pmonitor);
1.231 provos 609:
1.242 mouring 610: pmonitor->m_pid = fork();
611: if (pmonitor->m_pid == -1)
1.231 provos 612: fatal("fork of unprivileged child failed");
1.242 mouring 613: else if (pmonitor->m_pid != 0) {
1.364 markus 614: verbose("User child is on pid %ld", (long)pmonitor->m_pid);
1.307 otto 615: buffer_clear(&loginmsg);
1.490 markus 616: monitor_clear_keystate(pmonitor);
1.242 mouring 617: monitor_child_postauth(pmonitor);
1.231 provos 618:
619: /* NEVERREACHED */
620: exit(0);
621: }
622:
1.383 djm 623: /* child */
624:
1.242 mouring 625: close(pmonitor->m_sendfd);
1.383 djm 626: pmonitor->m_sendfd = -1;
1.231 provos 627:
628: /* Demote the private keys to public keys. */
629: demote_sensitive_data();
1.354 djm 630:
1.231 provos 631: /* Drop privileges */
632: do_setusercontext(authctxt->pw);
633:
1.315 djm 634: skip:
1.231 provos 635: /* It is safe now to apply the key state */
1.242 mouring 636: monitor_apply_keystate(pmonitor);
1.312 markus 637:
638: /*
639: * Tell the packet layer that authentication was successful, since
640: * this information is not part of the key state.
641: */
642: packet_set_authenticated();
1.231 provos 643: }
644:
1.200 itojun 645: static char *
1.134 markus 646: list_hostkey_types(void)
647: {
1.223 markus 648: Buffer b;
1.281 jakob 649: const char *p;
650: char *ret;
1.493 djm 651: u_int i;
1.488 markus 652: struct sshkey *key;
1.223 markus 653:
654: buffer_init(&b);
1.217 deraadt 655: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 656: key = sensitive_data.host_keys[i];
1.443 djm 657: if (key == NULL)
1.404 markus 658: key = sensitive_data.host_pubkeys[i];
1.472 markus 659: if (key == NULL)
1.134 markus 660: continue;
1.454 markus 661: /* Check that the key is accepted in HostkeyAlgorithms */
662: if (match_pattern_list(sshkey_ssh_name(key),
663: options.hostkeyalgorithms, 0) != 1) {
664: debug3("%s: %s key not permitted by HostkeyAlgorithms",
665: __func__, sshkey_ssh_name(key));
666: continue;
667: }
1.214 deraadt 668: switch (key->type) {
1.134 markus 669: case KEY_RSA:
670: case KEY_DSA:
1.378 djm 671: case KEY_ECDSA:
1.412 markus 672: case KEY_ED25519:
1.223 markus 673: if (buffer_len(&b) > 0)
674: buffer_append(&b, ",", 1);
675: p = key_ssh_name(key);
676: buffer_append(&b, p, strlen(p));
1.461 markus 677:
678: /* for RSA we also support SHA2 signatures */
679: if (key->type == KEY_RSA) {
680: p = ",rsa-sha2-512,rsa-sha2-256";
681: buffer_append(&b, p, strlen(p));
682: }
1.134 markus 683: break;
684: }
1.373 djm 685: /* If the private key has a cert peer, then list that too */
686: key = sensitive_data.host_certificates[i];
687: if (key == NULL)
688: continue;
689: switch (key->type) {
690: case KEY_RSA_CERT:
691: case KEY_DSA_CERT:
1.378 djm 692: case KEY_ECDSA_CERT:
1.412 markus 693: case KEY_ED25519_CERT:
1.373 djm 694: if (buffer_len(&b) > 0)
695: buffer_append(&b, ",", 1);
696: p = key_ssh_name(key);
697: buffer_append(&b, p, strlen(p));
698: break;
699: }
1.134 markus 700: }
1.467 djm 701: if ((ret = sshbuf_dup_string(&b)) == NULL)
702: fatal("%s: sshbuf_dup_string failed", __func__);
1.223 markus 703: buffer_free(&b);
1.281 jakob 704: debug("list_hostkey_types: %s", ret);
705: return ret;
1.134 markus 706: }
707:
1.488 markus 708: static struct sshkey *
1.440 djm 709: get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
1.134 markus 710: {
1.493 djm 711: u_int i;
1.488 markus 712: struct sshkey *key;
1.250 deraadt 713:
1.217 deraadt 714: for (i = 0; i < options.num_host_key_files; i++) {
1.375 djm 715: switch (type) {
716: case KEY_RSA_CERT:
717: case KEY_DSA_CERT:
1.378 djm 718: case KEY_ECDSA_CERT:
1.412 markus 719: case KEY_ED25519_CERT:
1.373 djm 720: key = sensitive_data.host_certificates[i];
1.375 djm 721: break;
722: default:
1.373 djm 723: key = sensitive_data.host_keys[i];
1.404 markus 724: if (key == NULL && !need_private)
725: key = sensitive_data.host_pubkeys[i];
1.375 djm 726: break;
727: }
1.440 djm 728: if (key != NULL && key->type == type &&
729: (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
1.373 djm 730: return need_private ?
731: sensitive_data.host_keys[i] : key;
1.134 markus 732: }
733: return NULL;
1.96 markus 734: }
735:
1.488 markus 736: struct sshkey *
1.440 djm 737: get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 738: {
1.440 djm 739: return get_hostkey_by_type(type, nid, 0, ssh);
1.373 djm 740: }
741:
1.488 markus 742: struct sshkey *
1.440 djm 743: get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 744: {
1.440 djm 745: return get_hostkey_by_type(type, nid, 1, ssh);
1.373 djm 746: }
747:
1.488 markus 748: struct sshkey *
1.231 provos 749: get_hostkey_by_index(int ind)
750: {
1.493 djm 751: if (ind < 0 || (u_int)ind >= options.num_host_key_files)
1.231 provos 752: return (NULL);
753: return (sensitive_data.host_keys[ind]);
754: }
755:
1.488 markus 756: struct sshkey *
1.435 markus 757: get_hostkey_public_by_index(int ind, struct ssh *ssh)
1.404 markus 758: {
1.493 djm 759: if (ind < 0 || (u_int)ind >= options.num_host_key_files)
1.404 markus 760: return (NULL);
761: return (sensitive_data.host_pubkeys[ind]);
762: }
763:
1.231 provos 764: int
1.488 markus 765: get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh)
1.231 provos 766: {
1.493 djm 767: u_int i;
1.250 deraadt 768:
1.231 provos 769: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 770: if (key_is_cert(key)) {
1.442 djm 771: if (key == sensitive_data.host_certificates[i] ||
772: (compare && sensitive_data.host_certificates[i] &&
773: sshkey_equal(key,
774: sensitive_data.host_certificates[i])))
1.373 djm 775: return (i);
776: } else {
1.442 djm 777: if (key == sensitive_data.host_keys[i] ||
778: (compare && sensitive_data.host_keys[i] &&
779: sshkey_equal(key, sensitive_data.host_keys[i])))
1.373 djm 780: return (i);
1.442 djm 781: if (key == sensitive_data.host_pubkeys[i] ||
782: (compare && sensitive_data.host_pubkeys[i] &&
783: sshkey_equal(key, sensitive_data.host_pubkeys[i])))
1.404 markus 784: return (i);
1.373 djm 785: }
1.231 provos 786: }
787: return (-1);
788: }
789:
1.439 djm 790: /* Inform the client of all hostkeys */
791: static void
792: notify_hostkeys(struct ssh *ssh)
793: {
794: struct sshbuf *buf;
795: struct sshkey *key;
1.493 djm 796: u_int i, nkeys;
797: int r;
1.439 djm 798: char *fp;
1.446 dtucker 799:
800: /* Some clients cannot cope with the hostkeys message, skip those. */
801: if (datafellows & SSH_BUG_HOSTKEYS)
802: return;
1.439 djm 803:
804: if ((buf = sshbuf_new()) == NULL)
805: fatal("%s: sshbuf_new", __func__);
806: for (i = nkeys = 0; i < options.num_host_key_files; i++) {
807: key = get_hostkey_public_by_index(i, ssh);
808: if (key == NULL || key->type == KEY_UNSPEC ||
1.472 markus 809: sshkey_is_cert(key))
1.439 djm 810: continue;
811: fp = sshkey_fingerprint(key, options.fingerprint_hash,
812: SSH_FP_DEFAULT);
813: debug3("%s: key %d: %s %s", __func__, i,
814: sshkey_ssh_name(key), fp);
815: free(fp);
1.442 djm 816: if (nkeys == 0) {
817: packet_start(SSH2_MSG_GLOBAL_REQUEST);
1.444 djm 818: packet_put_cstring("hostkeys-00@openssh.com");
1.442 djm 819: packet_put_char(0); /* want-reply */
820: }
821: sshbuf_reset(buf);
822: if ((r = sshkey_putb(key, buf)) != 0)
1.439 djm 823: fatal("%s: couldn't put hostkey %d: %s",
824: __func__, i, ssh_err(r));
1.442 djm 825: packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
1.439 djm 826: nkeys++;
827: }
1.493 djm 828: debug3("%s: sent %u hostkeys", __func__, nkeys);
1.439 djm 829: if (nkeys == 0)
830: fatal("%s: no hostkeys", __func__);
831: packet_send();
1.442 djm 832: sshbuf_free(buf);
1.439 djm 833: }
834:
1.124 markus 835: /*
836: * returns 1 if connection should be dropped, 0 otherwise.
837: * dropping starts at connection #max_startups_begin with a probability
838: * of (max_startups_rate/100). the probability increases linearly until
839: * all connections are dropped for startups > max_startups
840: */
1.200 itojun 841: static int
1.124 markus 842: drop_connection(int startups)
843: {
1.303 mickey 844: int p, r;
1.124 markus 845:
846: if (startups < options.max_startups_begin)
847: return 0;
848: if (startups >= options.max_startups)
849: return 1;
850: if (options.max_startups_rate == 100)
851: return 1;
852:
853: p = 100 - options.max_startups_rate;
854: p *= startups - options.max_startups_begin;
1.303 mickey 855: p /= options.max_startups - options.max_startups_begin;
1.124 markus 856: p += options.max_startups_rate;
1.356 djm 857: r = arc4random_uniform(100);
1.124 markus 858:
1.304 djm 859: debug("drop_connection: p %d, r %d", p, r);
1.124 markus 860: return (r < p) ? 1 : 0;
861: }
862:
1.215 markus 863: static void
864: usage(void)
865: {
1.290 markus 866: fprintf(stderr, "%s, %s\n",
1.426 markus 867: SSH_VERSION,
868: #ifdef WITH_OPENSSL
869: SSLeay_version(SSLEAY_VERSION)
870: #else
871: "without OpenSSL"
872: #endif
873: );
1.289 markus 874: fprintf(stderr,
1.473 naddy 875: "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n"
1.399 dtucker 876: " [-E log_file] [-f config_file] [-g login_grace_time]\n"
1.473 naddy 877: " [-h host_key_file] [-o option] [-p port] [-u len]\n"
1.289 markus 878: );
1.215 markus 879: exit(1);
880: }
881:
1.294 djm 882: static void
1.467 djm 883: send_rexec_state(int fd, struct sshbuf *conf)
1.294 djm 884: {
1.467 djm 885: struct sshbuf *m;
886: int r;
1.294 djm 887:
1.467 djm 888: debug3("%s: entering fd = %d config len %zu", __func__, fd,
889: sshbuf_len(conf));
1.294 djm 890:
891: /*
892: * Protocol from reexec master to child:
893: * string configuration
894: */
1.467 djm 895: if ((m = sshbuf_new()) == NULL)
896: fatal("%s: sshbuf_new failed", __func__);
897: if ((r = sshbuf_put_stringb(m, conf)) != 0)
898: fatal("%s: buffer error: %s", __func__, ssh_err(r));
899: if (ssh_msg_send(fd, 0, m) == -1)
1.294 djm 900: fatal("%s: ssh_msg_send failed", __func__);
901:
1.467 djm 902: sshbuf_free(m);
1.294 djm 903:
904: debug3("%s: done", __func__);
905: }
906:
907: static void
908: recv_rexec_state(int fd, Buffer *conf)
909: {
910: Buffer m;
911: char *cp;
912: u_int len;
913:
914: debug3("%s: entering fd = %d", __func__, fd);
915:
916: buffer_init(&m);
917:
918: if (ssh_msg_recv(fd, &m) == -1)
919: fatal("%s: ssh_msg_recv failed", __func__);
920: if (buffer_get_char(&m) != 0)
921: fatal("%s: rexec version mismatch", __func__);
922:
923: cp = buffer_get_string(&m, &len);
924: if (conf != NULL)
1.469 djm 925: buffer_append(conf, cp, len);
1.402 djm 926: free(cp);
1.294 djm 927:
928: buffer_free(&m);
929:
930: debug3("%s: done", __func__);
931: }
932:
1.345 djm 933: /* Accept a connection from inetd */
934: static void
935: server_accept_inetd(int *sock_in, int *sock_out)
936: {
937: int fd;
938:
939: startup_pipe = -1;
940: if (rexeced_flag) {
941: close(REEXEC_CONFIG_PASS_FD);
942: *sock_in = *sock_out = dup(STDIN_FILENO);
943: if (!debug_flag) {
944: startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
945: close(REEXEC_STARTUP_PIPE_FD);
946: }
947: } else {
948: *sock_in = dup(STDIN_FILENO);
949: *sock_out = dup(STDOUT_FILENO);
950: }
951: /*
952: * We intentionally do not close the descriptors 0, 1, and 2
953: * as our code for setting the descriptors won't work if
954: * ttyfd happens to be one of those.
955: */
956: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
957: dup2(fd, STDIN_FILENO);
958: dup2(fd, STDOUT_FILENO);
1.403 dtucker 959: if (!log_stderr)
960: dup2(fd, STDERR_FILENO);
961: if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1.345 djm 962: close(fd);
963: }
964: debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
965: }
966:
967: /*
968: * Listen for TCP connections
969: */
970: static void
1.494 djm 971: listen_on_addrs(struct listenaddr *la)
1.345 djm 972: {
1.494 djm 973: int ret, listen_sock;
1.345 djm 974: struct addrinfo *ai;
975: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
976:
1.494 djm 977: for (ai = la->addrs; ai; ai = ai->ai_next) {
1.345 djm 978: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
979: continue;
980: if (num_listen_socks >= MAX_LISTEN_SOCKS)
981: fatal("Too many listen sockets. "
982: "Enlarge MAX_LISTEN_SOCKS");
983: if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
984: ntop, sizeof(ntop), strport, sizeof(strport),
985: NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
986: error("getnameinfo failed: %.100s",
1.352 dtucker 987: ssh_gai_strerror(ret));
1.345 djm 988: continue;
989: }
990: /* Create socket for listening. */
1.370 dtucker 991: listen_sock = socket(ai->ai_family, ai->ai_socktype,
992: ai->ai_protocol);
1.345 djm 993: if (listen_sock < 0) {
994: /* kernel may not support ipv6 */
995: verbose("socket: %.100s", strerror(errno));
996: continue;
997: }
998: if (set_nonblock(listen_sock) == -1) {
1.483 djm 999: close(listen_sock);
1000: continue;
1001: }
1002: if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) {
1003: verbose("socket: CLOEXEC: %s", strerror(errno));
1.345 djm 1004: close(listen_sock);
1005: continue;
1006: }
1.494 djm 1007: /* Socket options */
1008: set_reuseaddr(listen_sock);
1009: if (la->rdomain != NULL &&
1010: set_rdomain(listen_sock, la->rdomain) == -1) {
1011: close(listen_sock);
1012: continue;
1013: }
1.345 djm 1014:
1015: debug("Bind to port %s on %s.", strport, ntop);
1016:
1017: /* Bind the socket to the desired port. */
1018: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1019: error("Bind to port %s on %s failed: %.200s.",
1020: strport, ntop, strerror(errno));
1021: close(listen_sock);
1022: continue;
1023: }
1024: listen_socks[num_listen_socks] = listen_sock;
1025: num_listen_socks++;
1026:
1027: /* Start listening on the port. */
1028: if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1029: fatal("listen on [%s]:%s: %.100s",
1030: ntop, strport, strerror(errno));
1.494 djm 1031: logit("Server listening on %s port %s%s%s.",
1032: ntop, strport,
1033: la->rdomain == NULL ? "" : " rdomain ",
1034: la->rdomain == NULL ? "" : la->rdomain);
1.345 djm 1035: }
1.494 djm 1036: }
1037:
1038: static void
1039: server_listen(void)
1040: {
1041: u_int i;
1042:
1043: for (i = 0; i < options.num_listen_addrs; i++) {
1044: listen_on_addrs(&options.listen_addrs[i]);
1045: freeaddrinfo(options.listen_addrs[i].addrs);
1046: free(options.listen_addrs[i].rdomain);
1047: memset(&options.listen_addrs[i], 0,
1048: sizeof(options.listen_addrs[i]));
1049: }
1050: free(options.listen_addrs);
1051: options.listen_addrs = NULL;
1052: options.num_listen_addrs = 0;
1.345 djm 1053:
1054: if (!num_listen_socks)
1055: fatal("Cannot bind any address.");
1056: }
1057:
1058: /*
1059: * The main TCP accept loop. Note that, for the non-debug case, returns
1060: * from this function are in a forked subprocess.
1061: */
1062: static void
1063: server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1064: {
1065: fd_set *fdset;
1066: int i, j, ret, maxfd;
1.472 markus 1067: int startups = 0;
1.345 djm 1068: int startup_p[2] = { -1 , -1 };
1069: struct sockaddr_storage from;
1070: socklen_t fromlen;
1071: pid_t pid;
1072:
1073: /* setup fd set for accept */
1074: fdset = NULL;
1075: maxfd = 0;
1076: for (i = 0; i < num_listen_socks; i++)
1077: if (listen_socks[i] > maxfd)
1078: maxfd = listen_socks[i];
1079: /* pipes connected to unauthenticated childs */
1080: startup_pipes = xcalloc(options.max_startups, sizeof(int));
1081: for (i = 0; i < options.max_startups; i++)
1082: startup_pipes[i] = -1;
1083:
1084: /*
1085: * Stay listening for connections until the system crashes or
1086: * the daemon is killed with a signal.
1087: */
1088: for (;;) {
1089: if (received_sighup)
1090: sighup_restart();
1.462 mmcc 1091: free(fdset);
1.458 deraadt 1092: fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1.345 djm 1093: sizeof(fd_mask));
1094:
1095: for (i = 0; i < num_listen_socks; i++)
1096: FD_SET(listen_socks[i], fdset);
1097: for (i = 0; i < options.max_startups; i++)
1098: if (startup_pipes[i] != -1)
1099: FD_SET(startup_pipes[i], fdset);
1100:
1101: /* Wait in select until there is a connection. */
1102: ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1103: if (ret < 0 && errno != EINTR)
1104: error("select: %.100s", strerror(errno));
1105: if (received_sigterm) {
1106: logit("Received signal %d; terminating.",
1107: (int) received_sigterm);
1108: close_listen_socks();
1.430 djm 1109: if (options.pid_file != NULL)
1110: unlink(options.pid_file);
1.382 djm 1111: exit(received_sigterm == SIGTERM ? 0 : 255);
1.345 djm 1112: }
1113: if (ret < 0)
1114: continue;
1115:
1116: for (i = 0; i < options.max_startups; i++)
1117: if (startup_pipes[i] != -1 &&
1118: FD_ISSET(startup_pipes[i], fdset)) {
1119: /*
1120: * the read end of the pipe is ready
1121: * if the child has closed the pipe
1122: * after successful authentication
1123: * or if the child has died
1124: */
1125: close(startup_pipes[i]);
1126: startup_pipes[i] = -1;
1127: startups--;
1128: }
1129: for (i = 0; i < num_listen_socks; i++) {
1130: if (!FD_ISSET(listen_socks[i], fdset))
1131: continue;
1132: fromlen = sizeof(from);
1133: *newsock = accept(listen_socks[i],
1134: (struct sockaddr *)&from, &fromlen);
1135: if (*newsock < 0) {
1.398 markus 1136: if (errno != EINTR && errno != EWOULDBLOCK &&
1137: errno != ECONNABORTED)
1.389 djm 1138: error("accept: %.100s",
1139: strerror(errno));
1140: if (errno == EMFILE || errno == ENFILE)
1141: usleep(100 * 1000);
1.345 djm 1142: continue;
1143: }
1144: if (unset_nonblock(*newsock) == -1) {
1145: close(*newsock);
1146: continue;
1147: }
1148: if (drop_connection(startups) == 1) {
1.480 djm 1149: char *laddr = get_local_ipaddr(*newsock);
1150: char *raddr = get_peer_ipaddr(*newsock);
1151:
1152: verbose("drop connection #%d from [%s]:%d "
1153: "on [%s]:%d past MaxStartups", startups,
1154: raddr, get_peer_port(*newsock),
1155: laddr, get_local_port(*newsock));
1156: free(laddr);
1157: free(raddr);
1.345 djm 1158: close(*newsock);
1159: continue;
1160: }
1161: if (pipe(startup_p) == -1) {
1162: close(*newsock);
1163: continue;
1164: }
1165:
1166: if (rexec_flag && socketpair(AF_UNIX,
1167: SOCK_STREAM, 0, config_s) == -1) {
1168: error("reexec socketpair: %s",
1169: strerror(errno));
1170: close(*newsock);
1171: close(startup_p[0]);
1172: close(startup_p[1]);
1173: continue;
1174: }
1175:
1176: for (j = 0; j < options.max_startups; j++)
1177: if (startup_pipes[j] == -1) {
1178: startup_pipes[j] = startup_p[0];
1179: if (maxfd < startup_p[0])
1180: maxfd = startup_p[0];
1181: startups++;
1182: break;
1183: }
1184:
1185: /*
1186: * Got connection. Fork a child to handle it, unless
1187: * we are in debugging mode.
1188: */
1189: if (debug_flag) {
1190: /*
1191: * In debugging mode. Close the listening
1192: * socket, and start processing the
1193: * connection without forking.
1194: */
1195: debug("Server will not fork when running in debugging mode.");
1196: close_listen_socks();
1197: *sock_in = *newsock;
1198: *sock_out = *newsock;
1199: close(startup_p[0]);
1200: close(startup_p[1]);
1201: startup_pipe = -1;
1202: pid = getpid();
1203: if (rexec_flag) {
1204: send_rexec_state(config_s[0],
1205: &cfg);
1206: close(config_s[0]);
1207: }
1208: break;
1209: }
1210:
1211: /*
1212: * Normal production daemon. Fork, and have
1213: * the child process the connection. The
1214: * parent continues listening.
1215: */
1216: if ((pid = fork()) == 0) {
1217: /*
1218: * Child. Close the listening and
1219: * max_startup sockets. Start using
1220: * the accepted socket. Reinitialize
1221: * logging (since our pid has changed).
1222: * We break out of the loop to handle
1223: * the connection.
1224: */
1225: startup_pipe = startup_p[1];
1226: close_startup_pipes();
1227: close_listen_socks();
1228: *sock_in = *newsock;
1229: *sock_out = *newsock;
1230: log_init(__progname,
1231: options.log_level,
1232: options.log_facility,
1233: log_stderr);
1234: if (rexec_flag)
1235: close(config_s[0]);
1236: break;
1237: }
1238:
1239: /* Parent. Stay in the loop. */
1240: if (pid < 0)
1241: error("fork: %.100s", strerror(errno));
1242: else
1243: debug("Forked child %ld.", (long)pid);
1244:
1245: close(startup_p[1]);
1246:
1247: if (rexec_flag) {
1248: send_rexec_state(config_s[0], &cfg);
1249: close(config_s[0]);
1250: close(config_s[1]);
1251: }
1252: close(*newsock);
1253: }
1254:
1255: /* child process check (or debug mode) */
1256: if (num_listen_socks < 0)
1257: break;
1258: }
1259: }
1260:
1.466 djm 1261: /*
1262: * If IP options are supported, make sure there are none (log and
1263: * return an error if any are found). Basically we are worried about
1264: * source routing; it can be used to pretend you are somebody
1265: * (ip-address) you are not. That itself may be "almost acceptable"
1266: * under certain circumstances, but rhosts autentication is useless
1267: * if source routing is accepted. Notice also that if we just dropped
1268: * source routing here, the other side could use IP spoofing to do
1269: * rest of the interaction and could still bypass security. So we
1270: * exit here if we detect any IP options.
1271: */
1272: static void
1273: check_ip_options(struct ssh *ssh)
1274: {
1275: int sock_in = ssh_packet_get_connection_in(ssh);
1276: struct sockaddr_storage from;
1277: u_char opts[200];
1.475 djm 1278: socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
1.466 djm 1279: char text[sizeof(opts) * 3 + 1];
1280:
1281: memset(&from, 0, sizeof(from));
1282: if (getpeername(sock_in, (struct sockaddr *)&from,
1283: &fromlen) < 0)
1284: return;
1285: if (from.ss_family != AF_INET)
1286: return;
1287: /* XXX IPv6 options? */
1288:
1289: if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
1290: &option_size) >= 0 && option_size != 0) {
1291: text[0] = '\0';
1292: for (i = 0; i < option_size; i++)
1293: snprintf(text + i*3, sizeof(text) - i*3,
1294: " %2.2x", opts[i]);
1295: fatal("Connection from %.100s port %d with IP opts: %.800s",
1296: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
1297: }
1298: return;
1299: }
1.345 djm 1300:
1.495 djm 1301: /* Set the routing domain for this process */
1302: static void
1303: set_process_rdomain(struct ssh *ssh, const char *name)
1304: {
1305: int rtable, ortable = getrtable();
1306: const char *errstr;
1307:
1308: if (name == NULL)
1309: return; /* default */
1310:
1311: if (strcmp(name, "%D") == 0) {
1312: /* "expands" to routing domain of connection */
1313: if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
1314: return;
1315: }
1316:
1317: rtable = (int)strtonum(name, 0, 255, &errstr);
1318: if (errstr != NULL) /* Shouldn't happen */
1319: fatal("Invalid routing domain \"%s\": %s", name, errstr);
1320: if (rtable != ortable && setrtable(rtable) != 0)
1321: fatal("Unable to set routing domain %d: %s",
1322: rtable, strerror(errno));
1323: debug("%s: set routing domain %d (was %d)", __func__, rtable, ortable);
1324: }
1325:
1.65 deraadt 1326: /*
1327: * Main program for the daemon.
1328: */
1.2 provos 1329: int
1330: main(int ac, char **av)
1.1 deraadt 1331: {
1.466 djm 1332: struct ssh *ssh = NULL;
1.64 markus 1333: extern char *optarg;
1334: extern int optind;
1.493 djm 1335: int r, opt, on = 1, already_daemon, remote_port;
1.297 avsm 1336: int sock_in = -1, sock_out = -1, newsock = -1;
1.496 djm 1337: const char *remote_ip, *rdomain;
1.447 dtucker 1338: char *fp, *line, *laddr, *logfile = NULL;
1.345 djm 1339: int config_s[2] = { -1 , -1 };
1.493 djm 1340: u_int i, j;
1.364 markus 1341: u_int64_t ibytes, obytes;
1.362 dtucker 1342: mode_t new_umask;
1.488 markus 1343: struct sshkey *key;
1344: struct sshkey *pubkey;
1.404 markus 1345: int keytype;
1.230 provos 1346: Authctxt *authctxt;
1.498 dtucker 1347: struct connection_info *connection_info = NULL;
1.64 markus 1348:
1.465 dtucker 1349: ssh_malloc_init(); /* must be called before any mallocs */
1.138 markus 1350: /* Save argv. */
1.64 markus 1351: saved_argv = av;
1.294 djm 1352: rexec_argc = ac;
1.313 djm 1353:
1354: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1355: sanitise_stdfd();
1.64 markus 1356:
1357: /* Initialize configuration options to their default values. */
1358: initialize_server_options(&options);
1359:
1360: /* Parse command-line arguments. */
1.450 djm 1361: while ((opt = getopt(ac, av,
1362: "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1.64 markus 1363: switch (opt) {
1.75 markus 1364: case '4':
1.305 djm 1365: options.address_family = AF_INET;
1.75 markus 1366: break;
1367: case '6':
1.305 djm 1368: options.address_family = AF_INET6;
1.75 markus 1369: break;
1.64 markus 1370: case 'f':
1371: config_file_name = optarg;
1372: break;
1.373 djm 1373: case 'c':
1.493 djm 1374: servconf_add_hostcert("[command-line]", 0,
1375: &options, optarg);
1.373 djm 1376: break;
1.64 markus 1377: case 'd':
1.273 markus 1378: if (debug_flag == 0) {
1.127 markus 1379: debug_flag = 1;
1380: options.log_level = SYSLOG_LEVEL_DEBUG1;
1.273 markus 1381: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1.127 markus 1382: options.log_level++;
1.64 markus 1383: break;
1.135 markus 1384: case 'D':
1385: no_daemon_flag = 1;
1.192 lebel 1386: break;
1.399 dtucker 1387: case 'E':
1.459 dtucker 1388: logfile = optarg;
1.399 dtucker 1389: /* FALLTHROUGH */
1.192 lebel 1390: case 'e':
1391: log_stderr = 1;
1.135 markus 1392: break;
1.64 markus 1393: case 'i':
1394: inetd_flag = 1;
1395: break;
1.294 djm 1396: case 'r':
1397: rexec_flag = 0;
1398: break;
1399: case 'R':
1400: rexeced_flag = 1;
1401: inetd_flag = 1;
1402: break;
1.64 markus 1403: case 'Q':
1.158 markus 1404: /* ignored */
1.64 markus 1405: break;
1406: case 'q':
1407: options.log_level = SYSLOG_LEVEL_QUIET;
1408: break;
1409: case 'b':
1.473 naddy 1410: /* protocol 1, ignored */
1.64 markus 1411: break;
1412: case 'p':
1.75 markus 1413: options.ports_from_cmdline = 1;
1.127 markus 1414: if (options.num_ports >= MAX_PORTS) {
1415: fprintf(stderr, "too many ports.\n");
1416: exit(1);
1417: }
1.193 stevesk 1418: options.ports[options.num_ports++] = a2port(optarg);
1.366 djm 1419: if (options.ports[options.num_ports-1] <= 0) {
1.193 stevesk 1420: fprintf(stderr, "Bad port number.\n");
1421: exit(1);
1422: }
1.64 markus 1423: break;
1424: case 'g':
1.197 stevesk 1425: if ((options.login_grace_time = convtime(optarg)) == -1) {
1426: fprintf(stderr, "Invalid login grace time.\n");
1427: exit(1);
1428: }
1.64 markus 1429: break;
1430: case 'k':
1.473 naddy 1431: /* protocol 1, ignored */
1.64 markus 1432: break;
1433: case 'h':
1.493 djm 1434: servconf_add_hostkey("[command-line]", 0,
1435: &options, optarg);
1.64 markus 1436: break;
1.203 stevesk 1437: case 't':
1438: test_flag = 1;
1439: break;
1.358 dtucker 1440: case 'T':
1441: test_flag = 2;
1442: break;
1443: case 'C':
1.498 dtucker 1444: connection_info = get_connection_info(0, 0);
1.391 dtucker 1445: if (parse_server_match_testspec(connection_info,
1446: optarg) == -1)
1447: exit(1);
1.358 dtucker 1448: break;
1.125 markus 1449: case 'u':
1.438 deraadt 1450: utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1451: if (utmp_len > HOST_NAME_MAX+1) {
1.257 stevesk 1452: fprintf(stderr, "Invalid utmp length.\n");
1453: exit(1);
1454: }
1.125 markus 1455: break;
1.215 markus 1456: case 'o':
1.283 markus 1457: line = xstrdup(optarg);
1458: if (process_server_config_line(&options, line,
1.391 dtucker 1459: "command-line", 0, NULL, NULL) != 0)
1.217 deraadt 1460: exit(1);
1.402 djm 1461: free(line);
1.215 markus 1462: break;
1.64 markus 1463: case '?':
1464: default:
1.215 markus 1465: usage();
1466: break;
1.64 markus 1467: }
1468: }
1.294 djm 1469: if (rexeced_flag || inetd_flag)
1470: rexec_flag = 0;
1.355 mbalmer 1471: if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1.294 djm 1472: fatal("sshd re-exec requires execution with an absolute path");
1473: if (rexeced_flag)
1.296 djm 1474: closefrom(REEXEC_MIN_FREE_FD);
1475: else
1476: closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1.294 djm 1477:
1.426 markus 1478: #ifdef WITH_OPENSSL
1.379 djm 1479: OpenSSL_add_all_algorithms();
1.426 markus 1480: #endif
1.64 markus 1481:
1.399 dtucker 1482: /* If requested, redirect the logs to the specified logfile. */
1.459 dtucker 1483: if (logfile != NULL)
1.399 dtucker 1484: log_redirect_stderr_to(logfile);
1.75 markus 1485: /*
1486: * Force logging to stderr until we have loaded the private host
1487: * key (unless started from inetd)
1488: */
1.138 markus 1489: log_init(__progname,
1.224 markus 1490: options.log_level == SYSLOG_LEVEL_NOT_SET ?
1491: SYSLOG_LEVEL_INFO : options.log_level,
1492: options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1493: SYSLOG_FACILITY_AUTH : options.log_facility,
1.261 markus 1494: log_stderr || !inetd_flag);
1.75 markus 1495:
1.294 djm 1496: sensitive_data.have_ssh2_key = 0;
1497:
1.358 dtucker 1498: /*
1.498 dtucker 1499: * If we're not doing an extended test do not silently ignore connection
1500: * test params.
1.358 dtucker 1501: */
1.498 dtucker 1502: if (test_flag < 2 && connection_info != NULL)
1.358 dtucker 1503: fatal("Config test connection parameter (-C) provided without "
1504: "test mode (-T)");
1505:
1.294 djm 1506: /* Fetch our configuration */
1507: buffer_init(&cfg);
1508: if (rexeced_flag)
1.296 djm 1509: recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
1.448 djm 1510: else if (strcasecmp(config_file_name, "none") != 0)
1.294 djm 1511: load_server_config(config_file_name, &cfg);
1512:
1.337 dtucker 1513: parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1.391 dtucker 1514: &cfg, NULL);
1.64 markus 1515:
1516: /* Fill in default values for those options not explicitly set. */
1517: fill_default_server_options(&options);
1.350 dtucker 1518:
1519: /* challenge-response is implemented via keyboard interactive */
1520: if (options.challenge_response_authentication)
1521: options.kbd_interactive_authentication = 1;
1.395 djm 1522:
1523: /* Check that options are sensible */
1524: if (options.authorized_keys_command_user == NULL &&
1525: (options.authorized_keys_command != NULL &&
1526: strcasecmp(options.authorized_keys_command, "none") != 0))
1527: fatal("AuthorizedKeysCommand set without "
1528: "AuthorizedKeysCommandUser");
1.449 djm 1529: if (options.authorized_principals_command_user == NULL &&
1530: (options.authorized_principals_command != NULL &&
1531: strcasecmp(options.authorized_principals_command, "none") != 0))
1532: fatal("AuthorizedPrincipalsCommand set without "
1533: "AuthorizedPrincipalsCommandUser");
1.396 djm 1534:
1535: /*
1536: * Check whether there is any path through configured auth methods.
1537: * Unfortunately it is not possible to verify this generally before
1538: * daemonisation in the presence of Match block, but this catches
1539: * and warns for trivial misconfigurations that could break login.
1540: */
1541: if (options.num_auth_methods != 0) {
1.493 djm 1542: for (i = 0; i < options.num_auth_methods; i++) {
1543: if (auth2_methods_valid(options.auth_methods[i],
1.396 djm 1544: 1) == 0)
1545: break;
1546: }
1.493 djm 1547: if (i >= options.num_auth_methods)
1.396 djm 1548: fatal("AuthenticationMethods cannot be satisfied by "
1549: "enabled authentication methods");
1550: }
1.305 djm 1551:
1.64 markus 1552: /* Check that there are no remaining arguments. */
1553: if (optind < ac) {
1554: fprintf(stderr, "Extra argument %s.\n", av[optind]);
1555: exit(1);
1556: }
1557:
1.397 dtucker 1558: debug("sshd version %s, %s", SSH_VERSION,
1.426 markus 1559: #ifdef WITH_OPENSSL
1560: SSLeay_version(SSLEAY_VERSION)
1561: #else
1562: "without OpenSSL"
1563: #endif
1564: );
1.64 markus 1565:
1.404 markus 1566: /* load host keys */
1.329 djm 1567: sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1.488 markus 1568: sizeof(struct sshkey *));
1.404 markus 1569: sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1.488 markus 1570: sizeof(struct sshkey *));
1.404 markus 1571:
1572: if (options.host_key_agent) {
1573: if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1574: setenv(SSH_AUTHSOCKET_ENV_NAME,
1575: options.host_key_agent, 1);
1.433 djm 1576: if ((r = ssh_get_authentication_socket(NULL)) == 0)
1577: have_agent = 1;
1578: else
1579: error("Could not connect to agent \"%s\": %s",
1580: options.host_key_agent, ssh_err(r));
1.404 markus 1581: }
1.134 markus 1582:
1.217 deraadt 1583: for (i = 0; i < options.num_host_key_files; i++) {
1.430 djm 1584: if (options.host_key_files[i] == NULL)
1585: continue;
1.179 markus 1586: key = key_load_private(options.host_key_files[i], "", NULL);
1.404 markus 1587: pubkey = key_load_public(options.host_key_files[i], NULL);
1.484 djm 1588:
1.439 djm 1589: if (pubkey == NULL && key != NULL)
1590: pubkey = key_demote(key);
1.179 markus 1591: sensitive_data.host_keys[i] = key;
1.404 markus 1592: sensitive_data.host_pubkeys[i] = pubkey;
1593:
1.472 markus 1594: if (key == NULL && pubkey != NULL && have_agent) {
1.443 djm 1595: debug("will rely on agent for hostkey %s",
1596: options.host_key_files[i]);
1.404 markus 1597: keytype = pubkey->type;
1598: } else if (key != NULL) {
1599: keytype = key->type;
1600: } else {
1.195 markus 1601: error("Could not load host key: %s",
1602: options.host_key_files[i]);
1.179 markus 1603: sensitive_data.host_keys[i] = NULL;
1.404 markus 1604: sensitive_data.host_pubkeys[i] = NULL;
1.134 markus 1605: continue;
1606: }
1.404 markus 1607:
1608: switch (keytype) {
1.134 markus 1609: case KEY_RSA:
1610: case KEY_DSA:
1.378 djm 1611: case KEY_ECDSA:
1.412 markus 1612: case KEY_ED25519:
1.441 djm 1613: if (have_agent || key != NULL)
1614: sensitive_data.have_ssh2_key = 1;
1.134 markus 1615: break;
1616: }
1.441 djm 1617: if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1618: SSH_FP_DEFAULT)) == NULL)
1619: fatal("sshkey_fingerprint failed");
1620: debug("%s host key #%d: %s %s",
1.472 markus 1621: key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp);
1.441 djm 1622: free(fp);
1.134 markus 1623: }
1.472 markus 1624: if (!sensitive_data.have_ssh2_key) {
1.264 itojun 1625: logit("sshd: no hostkeys available -- exiting.");
1.64 markus 1626: exit(1);
1627: }
1628:
1.373 djm 1629: /*
1630: * Load certificates. They are stored in an array at identical
1631: * indices to the public keys that they relate to.
1632: */
1633: sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1.488 markus 1634: sizeof(struct sshkey *));
1.373 djm 1635: for (i = 0; i < options.num_host_key_files; i++)
1636: sensitive_data.host_certificates[i] = NULL;
1637:
1638: for (i = 0; i < options.num_host_cert_files; i++) {
1.430 djm 1639: if (options.host_cert_files[i] == NULL)
1640: continue;
1.373 djm 1641: key = key_load_public(options.host_cert_files[i], NULL);
1642: if (key == NULL) {
1643: error("Could not load host certificate: %s",
1644: options.host_cert_files[i]);
1645: continue;
1646: }
1647: if (!key_is_cert(key)) {
1648: error("Certificate file is not a certificate: %s",
1649: options.host_cert_files[i]);
1650: key_free(key);
1651: continue;
1652: }
1653: /* Find matching private key */
1654: for (j = 0; j < options.num_host_key_files; j++) {
1655: if (key_equal_public(key,
1656: sensitive_data.host_keys[j])) {
1657: sensitive_data.host_certificates[j] = key;
1658: break;
1659: }
1660: }
1661: if (j >= options.num_host_key_files) {
1662: error("No matching private key for certificate: %s",
1663: options.host_cert_files[i]);
1664: key_free(key);
1665: continue;
1666: }
1667: sensitive_data.host_certificates[j] = key;
1.493 djm 1668: debug("host certificate: #%u type %d %s", j, key->type,
1.373 djm 1669: key_type(key));
1670: }
1.426 markus 1671:
1.244 markus 1672: if (use_privsep) {
1673: struct stat st;
1674:
1.327 deraadt 1675: if (getpwnam(SSH_PRIVSEP_USER) == NULL)
1.244 markus 1676: fatal("Privilege separation user %s does not exist",
1677: SSH_PRIVSEP_USER);
1.500 ! djm 1678: endpwent();
1.244 markus 1679: if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1680: (S_ISDIR(st.st_mode) == 0))
1681: fatal("Missing privilege separation directory: %s",
1.247 stevesk 1682: _PATH_PRIVSEP_CHROOT_DIR);
1683: if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1.262 markus 1684: fatal("%s must be owned by root and not group or "
1685: "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1.358 dtucker 1686: }
1687:
1688: if (test_flag > 1) {
1.499 djm 1689: /*
1690: * If no connection info was provided by -C then use
1691: * use a blank one that will cause no predicate to match.
1692: */
1693: if (connection_info == NULL)
1694: connection_info = get_connection_info(0, 0);
1.498 dtucker 1695: parse_server_match_config(&options, connection_info);
1.358 dtucker 1696: dump_config(&options);
1.108 markus 1697: }
1.203 stevesk 1698:
1699: /* Configuration looks good, so exit if in test mode. */
1700: if (test_flag)
1701: exit(0);
1.108 markus 1702:
1.294 djm 1703: if (rexec_flag) {
1.493 djm 1704: if (rexec_argc < 0)
1705: fatal("rexec_argc %d < 0", rexec_argc);
1.329 djm 1706: rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1.493 djm 1707: for (i = 0; i < (u_int)rexec_argc; i++) {
1.294 djm 1708: debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1709: rexec_argv[i] = saved_argv[i];
1710: }
1711: rexec_argv[rexec_argc] = "-R";
1712: rexec_argv[rexec_argc + 1] = NULL;
1713: }
1.362 dtucker 1714:
1715: /* Ensure that umask disallows at least group and world write */
1716: new_umask = umask(0077) | 0022;
1717: (void) umask(new_umask);
1.294 djm 1718:
1.108 markus 1719: /* Initialize the log (it is reinitialized below in case we forked). */
1.306 dtucker 1720: if (debug_flag && (!inetd_flag || rexeced_flag))
1.64 markus 1721: log_stderr = 1;
1.138 markus 1722: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1723:
1.108 markus 1724: /*
1.478 dtucker 1725: * If not in debugging mode, not started from inetd and not already
1726: * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
1727: * terminal, and fork. The original process exits.
1.108 markus 1728: */
1.478 dtucker 1729: already_daemon = daemonized();
1730: if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
1.345 djm 1731:
1.64 markus 1732: if (daemon(0, 0) < 0)
1733: fatal("daemon() failed: %.200s", strerror(errno));
1734:
1.477 dtucker 1735: disconnect_controlling_tty();
1.64 markus 1736: }
1737: /* Reinitialize the log (because of the fork above). */
1.138 markus 1738: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1739:
1740: /* Chdir to the root directory so that the current disk can be
1741: unmounted if desired. */
1.401 dtucker 1742: if (chdir("/") == -1)
1743: error("chdir(\"/\"): %s", strerror(errno));
1.217 deraadt 1744:
1.178 markus 1745: /* ignore SIGPIPE */
1746: signal(SIGPIPE, SIG_IGN);
1.64 markus 1747:
1.345 djm 1748: /* Get a connection, either from inetd or a listening TCP socket */
1.64 markus 1749: if (inetd_flag) {
1.345 djm 1750: server_accept_inetd(&sock_in, &sock_out);
1.64 markus 1751: } else {
1.345 djm 1752: server_listen();
1.75 markus 1753:
1.201 markus 1754: signal(SIGHUP, sighup_handler);
1.345 djm 1755: signal(SIGCHLD, main_sigchld_handler);
1.201 markus 1756: signal(SIGTERM, sigterm_handler);
1757: signal(SIGQUIT, sigterm_handler);
1758:
1.345 djm 1759: /*
1760: * Write out the pid file after the sigterm handler
1761: * is setup and the listen sockets are bound
1762: */
1.479 dtucker 1763: if (options.pid_file != NULL && !debug_flag) {
1.345 djm 1764: FILE *f = fopen(options.pid_file, "w");
1.201 markus 1765:
1.270 djm 1766: if (f == NULL) {
1767: error("Couldn't create pid file \"%s\": %s",
1768: options.pid_file, strerror(errno));
1769: } else {
1.245 mpech 1770: fprintf(f, "%ld\n", (long) getpid());
1.64 markus 1771: fclose(f);
1772: }
1773: }
1774:
1.345 djm 1775: /* Accept a connection and return in a forked child */
1776: server_accept_loop(&sock_in, &sock_out,
1777: &newsock, config_s);
1.1 deraadt 1778: }
1779:
1.64 markus 1780: /* This is the child processing a new connection. */
1.288 markus 1781: setproctitle("%s", "[accepted]");
1.294 djm 1782:
1.300 markus 1783: /*
1784: * Create a new session and process group since the 4.4BSD
1785: * setlogin() affects the entire process group. We don't
1786: * want the child to be able to affect the parent.
1787: */
1788: if (!debug_flag && !inetd_flag && setsid() < 0)
1789: error("setsid: %.100s", strerror(errno));
1790:
1.294 djm 1791: if (rexec_flag) {
1792: int fd;
1793:
1.296 djm 1794: debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1795: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1796: dup2(newsock, STDIN_FILENO);
1797: dup2(STDIN_FILENO, STDOUT_FILENO);
1798: if (startup_pipe == -1)
1.296 djm 1799: close(REEXEC_STARTUP_PIPE_FD);
1.407 djm 1800: else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
1.296 djm 1801: dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
1.407 djm 1802: close(startup_pipe);
1803: startup_pipe = REEXEC_STARTUP_PIPE_FD;
1804: }
1.294 djm 1805:
1.296 djm 1806: dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
1.294 djm 1807: close(config_s[1]);
1.296 djm 1808:
1.294 djm 1809: execv(rexec_argv[0], rexec_argv);
1810:
1811: /* Reexec has failed, fall back and continue */
1812: error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
1.296 djm 1813: recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
1.294 djm 1814: log_init(__progname, options.log_level,
1815: options.log_facility, log_stderr);
1816:
1817: /* Clean up fds */
1.296 djm 1818: close(REEXEC_CONFIG_PASS_FD);
1819: newsock = sock_out = sock_in = dup(STDIN_FILENO);
1.294 djm 1820: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1821: dup2(fd, STDIN_FILENO);
1822: dup2(fd, STDOUT_FILENO);
1823: if (fd > STDERR_FILENO)
1824: close(fd);
1825: }
1.296 djm 1826: debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1827: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1828: }
1.372 djm 1829:
1830: /* Executed child processes don't need these. */
1831: fcntl(sock_out, F_SETFD, FD_CLOEXEC);
1832: fcntl(sock_in, F_SETFD, FD_CLOEXEC);
1.64 markus 1833:
1.66 markus 1834: /*
1835: * Disable the key regeneration alarm. We will not regenerate the
1836: * key since we are no longer in a position to give it to anyone. We
1837: * will not restart on SIGHUP since it no longer makes sense.
1838: */
1.64 markus 1839: alarm(0);
1840: signal(SIGALRM, SIG_DFL);
1841: signal(SIGHUP, SIG_DFL);
1842: signal(SIGTERM, SIG_DFL);
1843: signal(SIGQUIT, SIG_DFL);
1844: signal(SIGCHLD, SIG_DFL);
1.150 markus 1845:
1.66 markus 1846: /*
1847: * Register our connection. This turns encryption off because we do
1848: * not have a key.
1849: */
1.64 markus 1850: packet_set_connection(sock_in, sock_out);
1.312 markus 1851: packet_set_server();
1.466 djm 1852: ssh = active_state; /* XXX */
1.492 djm 1853:
1.466 djm 1854: check_ip_options(ssh);
1.309 djm 1855:
1.492 djm 1856: /* Prepare the channels layer */
1857: channel_init_channels(ssh);
1858: channel_set_af(ssh, options.address_family);
1859: process_permitopen(ssh, &options);
1860:
1.309 djm 1861: /* Set SO_KEEPALIVE if requested. */
1862: if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1863: setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1864: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.1 deraadt 1865:
1.466 djm 1866: if ((remote_port = ssh_remote_port(ssh)) < 0) {
1867: debug("ssh_remote_port failed");
1.310 markus 1868: cleanup_exit(255);
1869: }
1.316 dtucker 1870:
1871: /*
1.331 markus 1872: * The rest of the code depends on the fact that
1.466 djm 1873: * ssh_remote_ipaddr() caches the remote ip, even if
1.331 markus 1874: * the socket goes away.
1875: */
1.466 djm 1876: remote_ip = ssh_remote_ipaddr(ssh);
1.209 markus 1877:
1.496 djm 1878: rdomain = ssh_packet_rdomain_in(ssh);
1879:
1.64 markus 1880: /* Log the connection. */
1.447 dtucker 1881: laddr = get_local_ipaddr(sock_in);
1.497 djm 1882: verbose("Connection from %s port %d on %s port %d%s%s%s",
1.496 djm 1883: remote_ip, remote_port, laddr, ssh_local_port(ssh),
1.497 djm 1884: rdomain == NULL ? "" : " rdomain \"",
1885: rdomain == NULL ? "" : rdomain,
1886: rdomain == NULL ? "" : "\"");
1.447 dtucker 1887: free(laddr);
1.1 deraadt 1888:
1.66 markus 1889: /*
1.317 djm 1890: * We don't want to listen forever unless the other side
1.66 markus 1891: * successfully authenticates itself. So we set up an alarm which is
1892: * cleared after successful authentication. A limit of zero
1.317 djm 1893: * indicates no limit. Note that we don't set the alarm in debugging
1.66 markus 1894: * mode; it is just annoying to have the server exit just when you
1895: * are about to discover the bug.
1896: */
1.64 markus 1897: signal(SIGALRM, grace_alarm_handler);
1898: if (!debug_flag)
1899: alarm(options.login_grace_time);
1900:
1.466 djm 1901: sshd_exchange_identification(ssh, sock_in, sock_out);
1.64 markus 1902: packet_set_nonblocking();
1.1 deraadt 1903:
1.278 markus 1904: /* allocate authentication context */
1.329 djm 1905: authctxt = xcalloc(1, sizeof(*authctxt));
1.278 markus 1906:
1907: /* XXX global for cleanup, access from other modules */
1908: the_authctxt = authctxt;
1909:
1.307 otto 1910: /* prepare buffer to collect messages to display to user after login */
1911: buffer_init(&loginmsg);
1.374 dtucker 1912: auth_debug_reset();
1.307 otto 1913:
1.404 markus 1914: if (use_privsep) {
1.278 markus 1915: if (privsep_preauth(authctxt) == 1)
1.237 markus 1916: goto authenticated;
1.472 markus 1917: } else if (have_agent) {
1.432 djm 1918: if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
1919: error("Unable to get agent socket: %s", ssh_err(r));
1.433 djm 1920: have_agent = 0;
1.432 djm 1921: }
1922: }
1.231 provos 1923:
1.77 markus 1924: /* perform the key exchange */
1925: /* authenticate user and start session */
1.472 markus 1926: do_ssh2_kex();
1927: do_authentication2(authctxt);
1928:
1.237 markus 1929: /*
1930: * If we use privilege separation, the unprivileged child transfers
1931: * the current keystate and exits
1932: */
1933: if (use_privsep) {
1.242 mouring 1934: mm_send_keystate(pmonitor);
1.490 markus 1935: packet_clear_keys();
1.231 provos 1936: exit(0);
1.237 markus 1937: }
1.231 provos 1938:
1939: authenticated:
1.318 djm 1940: /*
1941: * Cancel the alarm we set to limit the time taken for
1942: * authentication.
1943: */
1944: alarm(0);
1945: signal(SIGALRM, SIG_DFL);
1.347 markus 1946: authctxt->authenticated = 1;
1.318 djm 1947: if (startup_pipe != -1) {
1948: close(startup_pipe);
1949: startup_pipe = -1;
1950: }
1.495 djm 1951:
1952: if (options.routing_domain != NULL)
1953: set_process_rdomain(ssh, options.routing_domain);
1.318 djm 1954:
1.234 markus 1955: /*
1.231 provos 1956: * In privilege separation, we fork another child and prepare
1957: * file descriptor passing.
1958: */
1959: if (use_privsep) {
1.237 markus 1960: privsep_postauth(authctxt);
1961: /* the monitor process [priv] will not return */
1.231 provos 1962: }
1.360 dtucker 1963:
1964: packet_set_timeout(options.client_alive_interval,
1965: options.client_alive_count_max);
1.439 djm 1966:
1967: /* Try to send all our hostkeys to the client */
1.492 djm 1968: notify_hostkeys(ssh);
1.230 provos 1969:
1.278 markus 1970: /* Start session. */
1.492 djm 1971: do_authenticated(ssh, authctxt);
1.230 provos 1972:
1.64 markus 1973: /* The connection has been terminated. */
1.434 markus 1974: packet_get_bytes(&ibytes, &obytes);
1.381 djm 1975: verbose("Transferred: sent %llu, received %llu bytes",
1976: (unsigned long long)obytes, (unsigned long long)ibytes);
1.364 markus 1977:
1978: verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
1.64 markus 1979: packet_close();
1.231 provos 1980:
1981: if (use_privsep)
1982: mm_terminate();
1983:
1.64 markus 1984: exit(0);
1.1 deraadt 1985: }
1.98 markus 1986:
1.435 markus 1987: int
1.488 markus 1988: sshd_hostkey_sign(struct sshkey *privkey, struct sshkey *pubkey,
1989: u_char **signature, size_t *slen, const u_char *data, size_t dlen,
1990: const char *alg, u_int flag)
1.404 markus 1991: {
1.432 djm 1992: int r;
1.435 markus 1993: u_int xxx_slen, xxx_dlen = dlen;
1.432 djm 1994:
1.404 markus 1995: if (privkey) {
1.461 markus 1996: if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen,
1997: alg) < 0))
1.404 markus 1998: fatal("%s: key_sign failed", __func__);
1.435 markus 1999: if (slen)
2000: *slen = xxx_slen;
1.404 markus 2001: } else if (use_privsep) {
1.461 markus 2002: if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen,
2003: alg) < 0)
1.404 markus 2004: fatal("%s: pubkey_sign failed", __func__);
1.435 markus 2005: if (slen)
2006: *slen = xxx_slen;
1.404 markus 2007: } else {
1.435 markus 2008: if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
1.461 markus 2009: data, dlen, alg, datafellows)) != 0)
1.432 djm 2010: fatal("%s: ssh_agent_sign failed: %s",
2011: __func__, ssh_err(r));
1.404 markus 2012: }
1.435 markus 2013: return 0;
1.404 markus 2014: }
2015:
1.452 djm 2016: /* SSH2 key exchange */
1.200 itojun 2017: static void
1.142 markus 2018: do_ssh2_kex(void)
1.98 markus 2019: {
1.422 markus 2020: char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
1.435 markus 2021: struct kex *kex;
1.437 markus 2022: int r;
1.102 markus 2023:
1.457 djm 2024: myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
2025: options.kex_algorithms);
2026: myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
2027: options.ciphers);
2028: myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
2029: options.ciphers);
2030: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2031: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2032:
1.312 markus 2033: if (options.compression == COMP_NONE) {
1.246 markus 2034: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.470 dtucker 2035: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.102 markus 2036: }
1.400 dtucker 2037:
2038: if (options.rekey_limit || options.rekey_interval)
1.464 dtucker 2039: packet_set_rekey_limits(options.rekey_limit,
1.481 dtucker 2040: options.rekey_interval);
1.327 deraadt 2041:
1.413 djm 2042: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
2043: list_hostkey_types());
1.134 markus 2044:
1.189 markus 2045: /* start key exchange */
1.437 markus 2046: if ((r = kex_setup(active_state, myproposal)) != 0)
2047: fatal("kex_setup: %s", ssh_err(r));
1.435 markus 2048: kex = active_state->kex;
1.426 markus 2049: #ifdef WITH_OPENSSL
1.263 markus 2050: kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1.292 djm 2051: kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1.468 djm 2052: kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server;
2053: kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server;
2054: kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server;
1.263 markus 2055: kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1.324 djm 2056: kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1.378 djm 2057: kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1.426 markus 2058: #endif
1.410 markus 2059: kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1.186 markus 2060: kex->server = 1;
2061: kex->client_version_string=client_version_string;
2062: kex->server_version_string=server_version_string;
1.373 djm 2063: kex->load_host_public_key=&get_hostkey_public_by_type;
2064: kex->load_host_private_key=&get_hostkey_private_by_type;
1.231 provos 2065: kex->host_key_index=&get_hostkey_index;
1.404 markus 2066: kex->sign = sshd_hostkey_sign;
1.189 markus 2067:
1.489 markus 2068: ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done);
1.187 markus 2069:
2070: session_id2 = kex->session_id;
2071: session_id2_len = kex->session_id_len;
1.129 provos 2072:
2073: #ifdef DEBUG_KEXDH
2074: /* send 1st encrypted/maced/compressed message */
2075: packet_start(SSH2_MSG_IGNORE);
2076: packet_put_cstring("markus");
2077: packet_send();
2078: packet_write_wait();
2079: #endif
1.186 markus 2080: debug("KEX done");
1.278 markus 2081: }
2082:
2083: /* server specific fatal cleanup */
2084: void
2085: cleanup_exit(int i)
2086: {
1.492 djm 2087: struct ssh *ssh = active_state; /* XXX */
2088:
1.386 djm 2089: if (the_authctxt) {
1.492 djm 2090: do_cleanup(ssh, the_authctxt);
1.423 djm 2091: if (use_privsep && privsep_is_preauth &&
2092: pmonitor != NULL && pmonitor->m_pid > 1) {
1.386 djm 2093: debug("Killing privsep child %d", pmonitor->m_pid);
2094: if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
1.388 djm 2095: errno != ESRCH)
1.386 djm 2096: error("%s: kill(%d): %s", __func__,
2097: pmonitor->m_pid, strerror(errno));
2098: }
2099: }
1.278 markus 2100: _exit(i);
1.1 deraadt 2101: }
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