Annotation of src/usr.bin/ssh/sshd.c, Revision 1.513
1.513 ! djm 1: /* $OpenBSD: sshd.c,v 1.512 2018/07/11 18:53:29 markus 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"
1.511 markus 76: #include "sshbuf.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"
1.512 markus 84: #include "sshkey.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"
1.506 djm 104: #include "auth-options.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:
1.499 djm 130: /*
131: * Indicating that the daemon should only test the configuration and keys.
132: * If test_flag > 1 ("-T" flag), then sshd will also dump the effective
133: * configuration, optionally using connection information provided by the
134: * "-C" flag.
135: */
1.203 stevesk 136: int test_flag = 0;
137:
1.1 deraadt 138: /* Flag indicating that the daemon is being started from inetd. */
139: int inetd_flag = 0;
140:
1.135 markus 141: /* Flag indicating that sshd should not detach and become a daemon. */
142: int no_daemon_flag = 0;
143:
1.47 markus 144: /* debug goes to stderr unless inetd_flag is set */
145: int log_stderr = 0;
146:
1.1 deraadt 147: /* Saved arguments to main(). */
148: char **saved_argv;
149:
1.294 djm 150: /* re-exec */
151: int rexeced_flag = 0;
152: int rexec_flag = 1;
153: int rexec_argc = 0;
154: char **rexec_argv;
155:
1.66 markus 156: /*
1.75 markus 157: * The sockets that the server is listening; this is used in the SIGHUP
158: * signal handler.
1.66 markus 159: */
1.75 markus 160: #define MAX_LISTEN_SOCKS 16
161: int listen_socks[MAX_LISTEN_SOCKS];
162: int num_listen_socks = 0;
1.1 deraadt 163:
1.66 markus 164: /*
165: * the client's version string, passed by sshd2 in compat mode. if != NULL,
166: * sshd will skip the version-number exchange
167: */
1.61 markus 168: char *client_version_string = NULL;
1.96 markus 169: char *server_version_string = NULL;
1.1 deraadt 170:
1.404 markus 171: /* Daemon's agent connection */
1.432 djm 172: int auth_sock = -1;
1.404 markus 173: int have_agent = 0;
174:
1.66 markus 175: /*
176: * Any really sensitive data in the application is contained in this
177: * structure. The idea is that this structure could be locked into memory so
178: * that the pages do not get written into swap. However, there are some
179: * problems. The private key contains BIGNUMs, and we do not (in principle)
180: * have access to the internals of them, and locking just the structure is
181: * not very useful. Currently, memory locking is not implemented.
182: */
1.64 markus 183: struct {
1.488 markus 184: struct sshkey **host_keys; /* all private host keys */
185: struct sshkey **host_pubkeys; /* all public host keys */
186: struct sshkey **host_certificates; /* all public host certificates */
187: int have_ssh2_key;
1.1 deraadt 188: } sensitive_data;
189:
1.199 markus 190: /* This is set to true when a signal is received. */
1.212 markus 191: static volatile sig_atomic_t received_sighup = 0;
192: static volatile sig_atomic_t received_sigterm = 0;
1.1 deraadt 193:
1.96 markus 194: /* session identifier, used by RSA-auth */
1.140 markus 195: u_char session_id[16];
1.96 markus 196:
1.108 markus 197: /* same for ssh2 */
1.140 markus 198: u_char *session_id2 = NULL;
1.269 markus 199: u_int session_id2_len = 0;
1.108 markus 200:
1.125 markus 201: /* record remote hostname or ip */
1.438 deraadt 202: u_int utmp_len = HOST_NAME_MAX+1;
1.125 markus 203:
1.211 markus 204: /* options.max_startup sized array of fd ints */
205: int *startup_pipes = NULL;
206: int startup_pipe; /* in child */
207:
1.231 provos 208: /* variables used for privilege separation */
1.337 dtucker 209: int use_privsep = -1;
1.285 dtucker 210: struct monitor *pmonitor = NULL;
1.386 djm 211: int privsep_is_preauth = 1;
1.231 provos 212:
1.278 markus 213: /* global authentication context */
214: Authctxt *the_authctxt = NULL;
215:
1.506 djm 216: /* global key/cert auth options. XXX move to permanent ssh->authctxt? */
217: struct sshauthopt *auth_opts = NULL;
218:
1.337 dtucker 219: /* sshd_config buffer */
1.511 markus 220: struct sshbuf *cfg;
1.337 dtucker 221:
1.299 dtucker 222: /* message to be displayed after login */
1.510 markus 223: struct sshbuf *loginmsg;
1.299 dtucker 224:
1.1 deraadt 225: /* Prototypes for various functions defined later in this file. */
1.200 itojun 226: void destroy_sensitive_data(void);
1.231 provos 227: void demote_sensitive_data(void);
1.200 itojun 228: static void do_ssh2_kex(void);
1.129 provos 229:
1.87 markus 230: /*
1.75 markus 231: * Close all listening sockets
232: */
1.200 itojun 233: static void
1.75 markus 234: close_listen_socks(void)
235: {
236: int i;
1.250 deraadt 237:
1.75 markus 238: for (i = 0; i < num_listen_socks; i++)
239: close(listen_socks[i]);
240: num_listen_socks = -1;
241: }
242:
1.211 markus 243: static void
244: close_startup_pipes(void)
245: {
246: int i;
1.250 deraadt 247:
1.211 markus 248: if (startup_pipes)
249: for (i = 0; i < options.max_startups; i++)
250: if (startup_pipes[i] != -1)
251: close(startup_pipes[i]);
252: }
253:
1.75 markus 254: /*
1.65 deraadt 255: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
256: * the effect is to reread the configuration file (and to regenerate
257: * the server key).
258: */
1.327 deraadt 259:
260: /*ARGSUSED*/
1.200 itojun 261: static void
1.64 markus 262: sighup_handler(int sig)
1.1 deraadt 263: {
1.210 deraadt 264: int save_errno = errno;
265:
1.64 markus 266: received_sighup = 1;
1.210 deraadt 267: errno = save_errno;
1.1 deraadt 268: }
269:
1.65 deraadt 270: /*
271: * Called from the main program after receiving SIGHUP.
272: * Restarts the server.
273: */
1.200 itojun 274: static void
1.165 itojun 275: sighup_restart(void)
1.1 deraadt 276: {
1.264 itojun 277: logit("Received SIGHUP; restarting.");
1.479 dtucker 278: if (options.pid_file != NULL)
279: unlink(options.pid_file);
1.75 markus 280: close_listen_socks();
1.211 markus 281: close_startup_pipes();
1.349 dtucker 282: alarm(0); /* alarm timer persists across exec */
1.369 dtucker 283: signal(SIGHUP, SIG_IGN); /* will be restored after exec */
1.64 markus 284: execv(saved_argv[0], saved_argv);
1.264 itojun 285: logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
1.250 deraadt 286: strerror(errno));
1.64 markus 287: exit(1);
1.1 deraadt 288: }
289:
1.65 deraadt 290: /*
291: * Generic signal handler for terminating signals in the master daemon.
292: */
1.327 deraadt 293: /*ARGSUSED*/
1.200 itojun 294: static void
1.64 markus 295: sigterm_handler(int sig)
1.1 deraadt 296: {
1.199 markus 297: received_sigterm = sig;
1.1 deraadt 298: }
299:
1.65 deraadt 300: /*
301: * SIGCHLD handler. This is called whenever a child dies. This will then
1.199 markus 302: * reap any zombies left by exited children.
1.65 deraadt 303: */
1.327 deraadt 304: /*ARGSUSED*/
1.200 itojun 305: static void
1.64 markus 306: main_sigchld_handler(int sig)
1.1 deraadt 307: {
1.250 deraadt 308: int save_errno = errno;
1.239 markus 309: pid_t pid;
1.64 markus 310: int status;
1.60 deraadt 311:
1.239 markus 312: while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
313: (pid < 0 && errno == EINTR))
1.64 markus 314: ;
315: errno = save_errno;
1.1 deraadt 316: }
317:
1.65 deraadt 318: /*
319: * Signal handler for the alarm after the login grace period has expired.
320: */
1.327 deraadt 321: /*ARGSUSED*/
1.200 itojun 322: static void
1.64 markus 323: grace_alarm_handler(int sig)
1.1 deraadt 324: {
1.285 dtucker 325: if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
326: kill(pmonitor->m_pid, SIGALRM);
1.394 djm 327:
328: /*
329: * Try to kill any processes that we have spawned, E.g. authorized
330: * keys command helpers.
331: */
332: if (getpgid(0) == getpid()) {
333: signal(SIGTERM, SIG_IGN);
1.416 djm 334: kill(0, SIGTERM);
1.394 djm 335: }
1.285 dtucker 336:
1.64 markus 337: /* Log error and exit. */
1.466 djm 338: sigdie("Timeout before authentication for %s port %d",
339: ssh_remote_ipaddr(active_state), ssh_remote_port(active_state));
1.62 markus 340: }
341:
1.200 itojun 342: static void
1.466 djm 343: sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out)
1.96 markus 344: {
1.311 djm 345: u_int i;
1.96 markus 346: int remote_major, remote_minor;
1.482 djm 347: char *s;
1.96 markus 348: char buf[256]; /* Must not be larger than remote_version. */
349: char remote_version[256]; /* Must be at least as big as buf. */
350:
1.482 djm 351: xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s\r\n",
1.473 naddy 352: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,
1.390 djm 353: *options.version_addendum == '\0' ? "" : " ",
1.482 djm 354: options.version_addendum);
1.96 markus 355:
1.272 markus 356: /* Send our protocol version identification. */
1.463 markus 357: if (atomicio(vwrite, sock_out, server_version_string,
1.272 markus 358: strlen(server_version_string))
359: != strlen(server_version_string)) {
1.466 djm 360: logit("Could not write ident string to %s port %d",
361: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 362: cleanup_exit(255);
1.272 markus 363: }
364:
365: /* Read other sides version identification. */
366: memset(buf, 0, sizeof(buf));
367: for (i = 0; i < sizeof(buf) - 1; i++) {
1.463 markus 368: if (atomicio(read, sock_in, &buf[i], 1) != 1) {
1.466 djm 369: logit("Did not receive identification string "
370: "from %s port %d",
371: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 372: cleanup_exit(255);
1.96 markus 373: }
1.272 markus 374: if (buf[i] == '\r') {
375: buf[i] = 0;
376: /* Kludge for F-Secure Macintosh < 1.0.2 */
377: if (i == 12 &&
378: strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
1.96 markus 379: break;
1.272 markus 380: continue;
381: }
382: if (buf[i] == '\n') {
383: buf[i] = 0;
384: break;
1.96 markus 385: }
386: }
1.272 markus 387: buf[sizeof(buf) - 1] = 0;
388: client_version_string = xstrdup(buf);
1.96 markus 389:
390: /*
391: * Check that the versions match. In future this might accept
392: * several versions and set appropriate flags to handle them.
393: */
394: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
395: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 396: s = "Protocol mismatch.\n";
1.271 deraadt 397: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.408 djm 398: logit("Bad protocol version identification '%.100s' "
399: "from %s port %d", client_version_string,
1.466 djm 400: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.411 djm 401: close(sock_in);
402: close(sock_out);
1.278 markus 403: cleanup_exit(255);
1.96 markus 404: }
405: debug("Client protocol version %d.%d; client software version %.100s",
1.217 deraadt 406: remote_major, remote_minor, remote_version);
1.96 markus 407:
1.466 djm 408: ssh->compat = compat_datafellows(remote_version);
1.260 mickey 409:
1.466 djm 410: if ((ssh->compat & SSH_BUG_PROBE) != 0) {
411: logit("probed from %s port %d with %s. Don't panic.",
412: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
413: client_version_string);
1.278 markus 414: cleanup_exit(255);
1.260 mickey 415: }
1.466 djm 416: if ((ssh->compat & SSH_BUG_SCANNER) != 0) {
417: logit("scanned from %s port %d with %s. Don't panic.",
418: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
419: client_version_string);
1.278 markus 420: cleanup_exit(255);
1.175 deraadt 421: }
1.466 djm 422: if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) {
1.413 djm 423: logit("Client version \"%.100s\" uses unsafe RSA signature "
424: "scheme; disabling use of RSA keys", remote_version);
1.414 djm 425: }
1.98 markus 426:
1.102 markus 427: chop(server_version_string);
428: debug("Local version string %.200s", server_version_string);
429:
1.503 stsp 430: if (remote_major != 2 &&
1.501 djm 431: !(remote_major == 1 && remote_minor == 99)) {
1.96 markus 432: s = "Protocol major versions differ.\n";
1.271 deraadt 433: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.96 markus 434: close(sock_in);
435: close(sock_out);
1.466 djm 436: logit("Protocol major versions differ for %s port %d: "
437: "%.200s vs. %.200s",
438: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1.102 markus 439: server_version_string, client_version_string);
1.278 markus 440: cleanup_exit(255);
1.96 markus 441: }
1.108 markus 442: }
443:
1.134 markus 444: /* Destroy the host and server keys. They will no longer be needed. */
1.108 markus 445: void
446: destroy_sensitive_data(void)
447: {
1.493 djm 448: u_int i;
1.134 markus 449:
1.217 deraadt 450: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 451: if (sensitive_data.host_keys[i]) {
1.512 markus 452: sshkey_free(sensitive_data.host_keys[i]);
1.134 markus 453: sensitive_data.host_keys[i] = NULL;
454: }
1.373 djm 455: if (sensitive_data.host_certificates[i]) {
1.512 markus 456: sshkey_free(sensitive_data.host_certificates[i]);
1.373 djm 457: sensitive_data.host_certificates[i] = NULL;
458: }
1.134 markus 459: }
460: }
461:
1.231 provos 462: /* Demote private to public keys for network child */
463: void
464: demote_sensitive_data(void)
465: {
1.488 markus 466: struct sshkey *tmp;
1.493 djm 467: u_int i;
1.512 markus 468: int r;
1.231 provos 469:
470: for (i = 0; i < options.num_host_key_files; i++) {
471: if (sensitive_data.host_keys[i]) {
1.512 markus 472: if ((r = sshkey_demote(sensitive_data.host_keys[i],
473: &tmp)) != 0)
474: fatal("could not demote host %s key: %s",
475: sshkey_type(sensitive_data.host_keys[i]),
476: ssh_err(r));
477: sshkey_free(sensitive_data.host_keys[i]);
1.231 provos 478: sensitive_data.host_keys[i] = tmp;
479: }
1.373 djm 480: /* Certs do not need demotion */
1.231 provos 481: }
482: }
483:
1.233 markus 484: static void
1.231 provos 485: privsep_preauth_child(void)
486: {
1.253 deraadt 487: gid_t gidset[1];
1.250 deraadt 488: struct passwd *pw;
1.231 provos 489:
490: /* Enable challenge-response authentication for privilege separation */
491: privsep_challenge_enable();
1.419 djm 492:
1.420 markus 493: #ifdef GSSAPI
1.419 djm 494: /* Cache supported mechanism OIDs for later use */
495: if (options.gss_authentication)
496: ssh_gssapi_prepare_supported_oids();
1.420 markus 497: #endif
1.231 provos 498:
499: /* Demote the private keys to public keys. */
500: demote_sensitive_data();
501:
1.460 djm 502: /* Demote the child */
503: if (getuid() == 0 || geteuid() == 0) {
504: if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
505: fatal("Privilege separation user %s does not exist",
506: SSH_PRIVSEP_USER);
1.500 djm 507: pw = pwcopy(pw); /* Ensure mutable */
1.460 djm 508: endpwent();
1.500 djm 509: freezero(pw->pw_passwd, strlen(pw->pw_passwd));
1.460 djm 510:
511: /* Change our root directory */
512: if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
513: fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
514: strerror(errno));
515: if (chdir("/") == -1)
516: fatal("chdir(\"/\"): %s", strerror(errno));
517:
518: /*
519: * Drop our privileges
520: * NB. Can't use setusercontext() after chroot.
521: */
522: debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
523: (u_int)pw->pw_gid);
524: gidset[0] = pw->pw_gid;
525: if (setgroups(1, gidset) < 0)
526: fatal("setgroups: %.100s", strerror(errno));
527: permanently_set_uid(pw);
528: }
1.231 provos 529: }
530:
1.278 markus 531: static int
532: privsep_preauth(Authctxt *authctxt)
1.237 markus 533: {
1.432 djm 534: int status, r;
1.237 markus 535: pid_t pid;
1.384 djm 536: struct ssh_sandbox *box = NULL;
1.237 markus 537:
538: /* Set up unprivileged child process to deal with network data */
1.242 mouring 539: pmonitor = monitor_init();
1.237 markus 540: /* Store a pointer to the kex for later rekeying */
1.434 markus 541: pmonitor->m_pkex = &active_state->kex;
1.237 markus 542:
1.393 djm 543: if (use_privsep == PRIVSEP_ON)
1.384 djm 544: box = ssh_sandbox_init();
1.237 markus 545: pid = fork();
546: if (pid == -1) {
547: fatal("fork of unprivileged child failed");
548: } else if (pid != 0) {
1.245 mpech 549: debug2("Network child is on pid %ld", (long)pid);
1.237 markus 550:
1.392 markus 551: pmonitor->m_pid = pid;
1.432 djm 552: if (have_agent) {
553: r = ssh_get_authentication_socket(&auth_sock);
554: if (r != 0) {
555: error("Could not get agent socket: %s",
556: ssh_err(r));
557: have_agent = 0;
558: }
559: }
1.384 djm 560: if (box != NULL)
561: ssh_sandbox_parent_preauth(box, pid);
1.278 markus 562: monitor_child_preauth(authctxt, pmonitor);
1.237 markus 563:
564: /* Wait for the child's exit status */
1.384 djm 565: while (waitpid(pid, &status, 0) < 0) {
1.386 djm 566: if (errno == EINTR)
567: continue;
568: pmonitor->m_pid = -1;
569: fatal("%s: waitpid: %s", __func__, strerror(errno));
1.384 djm 570: }
1.386 djm 571: privsep_is_preauth = 0;
572: pmonitor->m_pid = -1;
1.384 djm 573: if (WIFEXITED(status)) {
574: if (WEXITSTATUS(status) != 0)
575: fatal("%s: preauth child exited with status %d",
576: __func__, WEXITSTATUS(status));
577: } else if (WIFSIGNALED(status))
578: fatal("%s: preauth child terminated by signal %d",
579: __func__, WTERMSIG(status));
580: if (box != NULL)
581: ssh_sandbox_parent_finish(box);
582: return 1;
1.237 markus 583: } else {
584: /* child */
1.383 djm 585: close(pmonitor->m_sendfd);
586: close(pmonitor->m_log_recvfd);
1.237 markus 587:
1.383 djm 588: /* Arrange for logging to be sent to the monitor */
589: set_log_handler(mm_log_handler, pmonitor);
1.237 markus 590:
1.460 djm 591: privsep_preauth_child();
1.238 stevesk 592: setproctitle("%s", "[net]");
1.384 djm 593: if (box != NULL)
594: ssh_sandbox_child(box);
595:
596: return 0;
1.237 markus 597: }
598: }
599:
1.233 markus 600: static void
1.237 markus 601: privsep_postauth(Authctxt *authctxt)
1.231 provos 602: {
1.474 djm 603: if (authctxt->pw->pw_uid == 0) {
1.231 provos 604: /* File descriptor passing is broken or root login */
605: use_privsep = 0;
1.315 djm 606: goto skip;
1.231 provos 607: }
1.234 markus 608:
1.231 provos 609: /* New socket pair */
1.242 mouring 610: monitor_reinit(pmonitor);
1.231 provos 611:
1.242 mouring 612: pmonitor->m_pid = fork();
613: if (pmonitor->m_pid == -1)
1.231 provos 614: fatal("fork of unprivileged child failed");
1.242 mouring 615: else if (pmonitor->m_pid != 0) {
1.364 markus 616: verbose("User child is on pid %ld", (long)pmonitor->m_pid);
1.510 markus 617: sshbuf_reset(loginmsg);
1.490 markus 618: monitor_clear_keystate(pmonitor);
1.242 mouring 619: monitor_child_postauth(pmonitor);
1.231 provos 620:
621: /* NEVERREACHED */
622: exit(0);
623: }
624:
1.383 djm 625: /* child */
626:
1.242 mouring 627: close(pmonitor->m_sendfd);
1.383 djm 628: pmonitor->m_sendfd = -1;
1.231 provos 629:
630: /* Demote the private keys to public keys. */
631: demote_sensitive_data();
1.354 djm 632:
1.231 provos 633: /* Drop privileges */
634: do_setusercontext(authctxt->pw);
635:
1.315 djm 636: skip:
1.231 provos 637: /* It is safe now to apply the key state */
1.242 mouring 638: monitor_apply_keystate(pmonitor);
1.312 markus 639:
640: /*
641: * Tell the packet layer that authentication was successful, since
642: * this information is not part of the key state.
643: */
644: packet_set_authenticated();
1.231 provos 645: }
646:
1.509 djm 647: static void
648: append_hostkey_type(struct sshbuf *b, const char *s)
649: {
650: int r;
651:
652: if (match_pattern_list(s, options.hostkeyalgorithms, 0) != 1) {
653: debug3("%s: %s key not permitted by HostkeyAlgorithms",
654: __func__, s);
655: return;
656: }
657: if ((r = sshbuf_putf(b, "%s%s", sshbuf_len(b) > 0 ? "," : "", s)) != 0)
658: fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r));
659: }
660:
1.200 itojun 661: static char *
1.134 markus 662: list_hostkey_types(void)
663: {
1.509 djm 664: struct sshbuf *b;
665: struct sshkey *key;
1.281 jakob 666: char *ret;
1.493 djm 667: u_int i;
1.223 markus 668:
1.509 djm 669: if ((b = sshbuf_new()) == NULL)
670: fatal("%s: sshbuf_new failed", __func__);
1.217 deraadt 671: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 672: key = sensitive_data.host_keys[i];
1.443 djm 673: if (key == NULL)
1.404 markus 674: key = sensitive_data.host_pubkeys[i];
1.472 markus 675: if (key == NULL)
1.134 markus 676: continue;
1.214 deraadt 677: switch (key->type) {
1.134 markus 678: case KEY_RSA:
1.509 djm 679: /* for RSA we also support SHA2 signatures */
680: append_hostkey_type(b, "rsa-sha2-512");
681: append_hostkey_type(b, "rsa-sha2-256");
682: /* FALLTHROUGH */
1.134 markus 683: case KEY_DSA:
1.378 djm 684: case KEY_ECDSA:
1.412 markus 685: case KEY_ED25519:
1.505 markus 686: case KEY_XMSS:
1.509 djm 687: append_hostkey_type(b, sshkey_ssh_name(key));
1.134 markus 688: break;
689: }
1.373 djm 690: /* If the private key has a cert peer, then list that too */
691: key = sensitive_data.host_certificates[i];
692: if (key == NULL)
693: continue;
694: switch (key->type) {
695: case KEY_RSA_CERT:
1.509 djm 696: /* for RSA we also support SHA2 signatures */
697: append_hostkey_type(b,
698: "rsa-sha2-512-cert-v01@openssh.com");
699: append_hostkey_type(b,
700: "rsa-sha2-256-cert-v01@openssh.com");
701: /* FALLTHROUGH */
1.373 djm 702: case KEY_DSA_CERT:
1.378 djm 703: case KEY_ECDSA_CERT:
1.412 markus 704: case KEY_ED25519_CERT:
1.505 markus 705: case KEY_XMSS_CERT:
1.509 djm 706: append_hostkey_type(b, sshkey_ssh_name(key));
1.373 djm 707: break;
708: }
1.134 markus 709: }
1.509 djm 710: if ((ret = sshbuf_dup_string(b)) == NULL)
1.467 djm 711: fatal("%s: sshbuf_dup_string failed", __func__);
1.509 djm 712: sshbuf_free(b);
713: debug("%s: %s", __func__, ret);
1.281 jakob 714: return ret;
1.134 markus 715: }
716:
1.488 markus 717: static struct sshkey *
1.440 djm 718: get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
1.134 markus 719: {
1.493 djm 720: u_int i;
1.488 markus 721: struct sshkey *key;
1.250 deraadt 722:
1.217 deraadt 723: for (i = 0; i < options.num_host_key_files; i++) {
1.375 djm 724: switch (type) {
725: case KEY_RSA_CERT:
726: case KEY_DSA_CERT:
1.378 djm 727: case KEY_ECDSA_CERT:
1.412 markus 728: case KEY_ED25519_CERT:
1.505 markus 729: case KEY_XMSS_CERT:
1.373 djm 730: key = sensitive_data.host_certificates[i];
1.375 djm 731: break;
732: default:
1.373 djm 733: key = sensitive_data.host_keys[i];
1.404 markus 734: if (key == NULL && !need_private)
735: key = sensitive_data.host_pubkeys[i];
1.375 djm 736: break;
737: }
1.440 djm 738: if (key != NULL && key->type == type &&
739: (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
1.373 djm 740: return need_private ?
741: sensitive_data.host_keys[i] : key;
1.134 markus 742: }
743: return NULL;
1.96 markus 744: }
745:
1.488 markus 746: struct sshkey *
1.440 djm 747: get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 748: {
1.440 djm 749: return get_hostkey_by_type(type, nid, 0, ssh);
1.373 djm 750: }
751:
1.488 markus 752: struct sshkey *
1.440 djm 753: get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 754: {
1.440 djm 755: return get_hostkey_by_type(type, nid, 1, ssh);
1.373 djm 756: }
757:
1.488 markus 758: struct sshkey *
1.231 provos 759: get_hostkey_by_index(int ind)
760: {
1.493 djm 761: if (ind < 0 || (u_int)ind >= options.num_host_key_files)
1.231 provos 762: return (NULL);
763: return (sensitive_data.host_keys[ind]);
764: }
765:
1.488 markus 766: struct sshkey *
1.435 markus 767: get_hostkey_public_by_index(int ind, struct ssh *ssh)
1.404 markus 768: {
1.493 djm 769: if (ind < 0 || (u_int)ind >= options.num_host_key_files)
1.404 markus 770: return (NULL);
771: return (sensitive_data.host_pubkeys[ind]);
772: }
773:
1.231 provos 774: int
1.488 markus 775: get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh)
1.231 provos 776: {
1.493 djm 777: u_int i;
1.250 deraadt 778:
1.231 provos 779: for (i = 0; i < options.num_host_key_files; i++) {
1.512 markus 780: if (sshkey_is_cert(key)) {
1.442 djm 781: if (key == sensitive_data.host_certificates[i] ||
782: (compare && sensitive_data.host_certificates[i] &&
783: sshkey_equal(key,
784: sensitive_data.host_certificates[i])))
1.373 djm 785: return (i);
786: } else {
1.442 djm 787: if (key == sensitive_data.host_keys[i] ||
788: (compare && sensitive_data.host_keys[i] &&
789: sshkey_equal(key, sensitive_data.host_keys[i])))
1.373 djm 790: return (i);
1.442 djm 791: if (key == sensitive_data.host_pubkeys[i] ||
792: (compare && sensitive_data.host_pubkeys[i] &&
793: sshkey_equal(key, sensitive_data.host_pubkeys[i])))
1.404 markus 794: return (i);
1.373 djm 795: }
1.231 provos 796: }
797: return (-1);
798: }
799:
1.439 djm 800: /* Inform the client of all hostkeys */
801: static void
802: notify_hostkeys(struct ssh *ssh)
803: {
804: struct sshbuf *buf;
805: struct sshkey *key;
1.493 djm 806: u_int i, nkeys;
807: int r;
1.439 djm 808: char *fp;
1.446 dtucker 809:
810: /* Some clients cannot cope with the hostkeys message, skip those. */
811: if (datafellows & SSH_BUG_HOSTKEYS)
812: return;
1.439 djm 813:
814: if ((buf = sshbuf_new()) == NULL)
815: fatal("%s: sshbuf_new", __func__);
816: for (i = nkeys = 0; i < options.num_host_key_files; i++) {
817: key = get_hostkey_public_by_index(i, ssh);
818: if (key == NULL || key->type == KEY_UNSPEC ||
1.472 markus 819: sshkey_is_cert(key))
1.439 djm 820: continue;
821: fp = sshkey_fingerprint(key, options.fingerprint_hash,
822: SSH_FP_DEFAULT);
823: debug3("%s: key %d: %s %s", __func__, i,
824: sshkey_ssh_name(key), fp);
825: free(fp);
1.442 djm 826: if (nkeys == 0) {
827: packet_start(SSH2_MSG_GLOBAL_REQUEST);
1.444 djm 828: packet_put_cstring("hostkeys-00@openssh.com");
1.442 djm 829: packet_put_char(0); /* want-reply */
830: }
831: sshbuf_reset(buf);
832: if ((r = sshkey_putb(key, buf)) != 0)
1.439 djm 833: fatal("%s: couldn't put hostkey %d: %s",
834: __func__, i, ssh_err(r));
1.442 djm 835: packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
1.439 djm 836: nkeys++;
837: }
1.493 djm 838: debug3("%s: sent %u hostkeys", __func__, nkeys);
1.439 djm 839: if (nkeys == 0)
840: fatal("%s: no hostkeys", __func__);
841: packet_send();
1.442 djm 842: sshbuf_free(buf);
1.439 djm 843: }
844:
1.124 markus 845: /*
846: * returns 1 if connection should be dropped, 0 otherwise.
847: * dropping starts at connection #max_startups_begin with a probability
848: * of (max_startups_rate/100). the probability increases linearly until
849: * all connections are dropped for startups > max_startups
850: */
1.200 itojun 851: static int
1.124 markus 852: drop_connection(int startups)
853: {
1.303 mickey 854: int p, r;
1.124 markus 855:
856: if (startups < options.max_startups_begin)
857: return 0;
858: if (startups >= options.max_startups)
859: return 1;
860: if (options.max_startups_rate == 100)
861: return 1;
862:
863: p = 100 - options.max_startups_rate;
864: p *= startups - options.max_startups_begin;
1.303 mickey 865: p /= options.max_startups - options.max_startups_begin;
1.124 markus 866: p += options.max_startups_rate;
1.356 djm 867: r = arc4random_uniform(100);
1.124 markus 868:
1.304 djm 869: debug("drop_connection: p %d, r %d", p, r);
1.124 markus 870: return (r < p) ? 1 : 0;
871: }
872:
1.215 markus 873: static void
874: usage(void)
875: {
1.290 markus 876: fprintf(stderr, "%s, %s\n",
1.426 markus 877: SSH_VERSION,
878: #ifdef WITH_OPENSSL
879: SSLeay_version(SSLEAY_VERSION)
880: #else
881: "without OpenSSL"
882: #endif
883: );
1.289 markus 884: fprintf(stderr,
1.473 naddy 885: "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n"
1.399 dtucker 886: " [-E log_file] [-f config_file] [-g login_grace_time]\n"
1.473 naddy 887: " [-h host_key_file] [-o option] [-p port] [-u len]\n"
1.289 markus 888: );
1.215 markus 889: exit(1);
890: }
891:
1.294 djm 892: static void
1.467 djm 893: send_rexec_state(int fd, struct sshbuf *conf)
1.294 djm 894: {
1.467 djm 895: struct sshbuf *m;
896: int r;
1.294 djm 897:
1.467 djm 898: debug3("%s: entering fd = %d config len %zu", __func__, fd,
899: sshbuf_len(conf));
1.294 djm 900:
901: /*
902: * Protocol from reexec master to child:
903: * string configuration
904: */
1.467 djm 905: if ((m = sshbuf_new()) == NULL)
906: fatal("%s: sshbuf_new failed", __func__);
907: if ((r = sshbuf_put_stringb(m, conf)) != 0)
908: fatal("%s: buffer error: %s", __func__, ssh_err(r));
909: if (ssh_msg_send(fd, 0, m) == -1)
1.294 djm 910: fatal("%s: ssh_msg_send failed", __func__);
911:
1.467 djm 912: sshbuf_free(m);
1.294 djm 913:
914: debug3("%s: done", __func__);
915: }
916:
917: static void
1.511 markus 918: recv_rexec_state(int fd, struct sshbuf *conf)
1.294 djm 919: {
1.511 markus 920: struct sshbuf *m;
921: u_char *cp, ver;
922: size_t len;
923: int r;
1.294 djm 924:
925: debug3("%s: entering fd = %d", __func__, fd);
926:
1.511 markus 927: if ((m = sshbuf_new()) == NULL)
928: fatal("%s: sshbuf_new failed", __func__);
929: if (ssh_msg_recv(fd, m) == -1)
1.294 djm 930: fatal("%s: ssh_msg_recv failed", __func__);
1.511 markus 931: if ((r = sshbuf_get_u8(m, &ver)) != 0)
932: fatal("%s: buffer error: %s", __func__, ssh_err(r));
933: if (ver != 0)
1.294 djm 934: fatal("%s: rexec version mismatch", __func__);
1.511 markus 935: if ((r = sshbuf_get_string(m, &cp, &len)) != 0)
936: fatal("%s: buffer error: %s", __func__, ssh_err(r));
937: if (conf != NULL && (r = sshbuf_put(conf, cp, len)))
938: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.294 djm 939:
1.402 djm 940: free(cp);
1.511 markus 941: sshbuf_free(m);
1.294 djm 942:
943: debug3("%s: done", __func__);
944: }
945:
1.345 djm 946: /* Accept a connection from inetd */
947: static void
948: server_accept_inetd(int *sock_in, int *sock_out)
949: {
950: int fd;
951:
952: startup_pipe = -1;
953: if (rexeced_flag) {
954: close(REEXEC_CONFIG_PASS_FD);
955: *sock_in = *sock_out = dup(STDIN_FILENO);
956: if (!debug_flag) {
957: startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
958: close(REEXEC_STARTUP_PIPE_FD);
959: }
960: } else {
961: *sock_in = dup(STDIN_FILENO);
962: *sock_out = dup(STDOUT_FILENO);
963: }
964: /*
965: * We intentionally do not close the descriptors 0, 1, and 2
966: * as our code for setting the descriptors won't work if
967: * ttyfd happens to be one of those.
968: */
969: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
970: dup2(fd, STDIN_FILENO);
971: dup2(fd, STDOUT_FILENO);
1.403 dtucker 972: if (!log_stderr)
973: dup2(fd, STDERR_FILENO);
974: if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1.345 djm 975: close(fd);
976: }
977: debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
978: }
979:
980: /*
981: * Listen for TCP connections
982: */
983: static void
1.494 djm 984: listen_on_addrs(struct listenaddr *la)
1.345 djm 985: {
1.494 djm 986: int ret, listen_sock;
1.345 djm 987: struct addrinfo *ai;
988: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
989:
1.494 djm 990: for (ai = la->addrs; ai; ai = ai->ai_next) {
1.345 djm 991: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
992: continue;
993: if (num_listen_socks >= MAX_LISTEN_SOCKS)
994: fatal("Too many listen sockets. "
995: "Enlarge MAX_LISTEN_SOCKS");
996: if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
997: ntop, sizeof(ntop), strport, sizeof(strport),
998: NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
999: error("getnameinfo failed: %.100s",
1.352 dtucker 1000: ssh_gai_strerror(ret));
1.345 djm 1001: continue;
1002: }
1003: /* Create socket for listening. */
1.370 dtucker 1004: listen_sock = socket(ai->ai_family, ai->ai_socktype,
1005: ai->ai_protocol);
1.345 djm 1006: if (listen_sock < 0) {
1007: /* kernel may not support ipv6 */
1008: verbose("socket: %.100s", strerror(errno));
1009: continue;
1010: }
1011: if (set_nonblock(listen_sock) == -1) {
1.483 djm 1012: close(listen_sock);
1013: continue;
1014: }
1015: if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) {
1016: verbose("socket: CLOEXEC: %s", strerror(errno));
1.345 djm 1017: close(listen_sock);
1018: continue;
1019: }
1.494 djm 1020: /* Socket options */
1021: set_reuseaddr(listen_sock);
1022: if (la->rdomain != NULL &&
1023: set_rdomain(listen_sock, la->rdomain) == -1) {
1024: close(listen_sock);
1025: continue;
1026: }
1.345 djm 1027:
1028: debug("Bind to port %s on %s.", strport, ntop);
1029:
1030: /* Bind the socket to the desired port. */
1031: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1032: error("Bind to port %s on %s failed: %.200s.",
1033: strport, ntop, strerror(errno));
1034: close(listen_sock);
1035: continue;
1036: }
1037: listen_socks[num_listen_socks] = listen_sock;
1038: num_listen_socks++;
1039:
1040: /* Start listening on the port. */
1041: if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1042: fatal("listen on [%s]:%s: %.100s",
1043: ntop, strport, strerror(errno));
1.494 djm 1044: logit("Server listening on %s port %s%s%s.",
1045: ntop, strport,
1046: la->rdomain == NULL ? "" : " rdomain ",
1047: la->rdomain == NULL ? "" : la->rdomain);
1.345 djm 1048: }
1.494 djm 1049: }
1050:
1051: static void
1052: server_listen(void)
1053: {
1054: u_int i;
1055:
1056: for (i = 0; i < options.num_listen_addrs; i++) {
1057: listen_on_addrs(&options.listen_addrs[i]);
1058: freeaddrinfo(options.listen_addrs[i].addrs);
1059: free(options.listen_addrs[i].rdomain);
1060: memset(&options.listen_addrs[i], 0,
1061: sizeof(options.listen_addrs[i]));
1062: }
1063: free(options.listen_addrs);
1064: options.listen_addrs = NULL;
1065: options.num_listen_addrs = 0;
1.345 djm 1066:
1067: if (!num_listen_socks)
1068: fatal("Cannot bind any address.");
1069: }
1070:
1071: /*
1072: * The main TCP accept loop. Note that, for the non-debug case, returns
1073: * from this function are in a forked subprocess.
1074: */
1075: static void
1076: server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1077: {
1078: fd_set *fdset;
1079: int i, j, ret, maxfd;
1.472 markus 1080: int startups = 0;
1.345 djm 1081: int startup_p[2] = { -1 , -1 };
1082: struct sockaddr_storage from;
1083: socklen_t fromlen;
1084: pid_t pid;
1085:
1086: /* setup fd set for accept */
1087: fdset = NULL;
1088: maxfd = 0;
1089: for (i = 0; i < num_listen_socks; i++)
1090: if (listen_socks[i] > maxfd)
1091: maxfd = listen_socks[i];
1092: /* pipes connected to unauthenticated childs */
1093: startup_pipes = xcalloc(options.max_startups, sizeof(int));
1094: for (i = 0; i < options.max_startups; i++)
1095: startup_pipes[i] = -1;
1096:
1097: /*
1098: * Stay listening for connections until the system crashes or
1099: * the daemon is killed with a signal.
1100: */
1101: for (;;) {
1102: if (received_sighup)
1103: sighup_restart();
1.462 mmcc 1104: free(fdset);
1.458 deraadt 1105: fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1.345 djm 1106: sizeof(fd_mask));
1107:
1108: for (i = 0; i < num_listen_socks; i++)
1109: FD_SET(listen_socks[i], fdset);
1110: for (i = 0; i < options.max_startups; i++)
1111: if (startup_pipes[i] != -1)
1112: FD_SET(startup_pipes[i], fdset);
1113:
1114: /* Wait in select until there is a connection. */
1115: ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1116: if (ret < 0 && errno != EINTR)
1117: error("select: %.100s", strerror(errno));
1118: if (received_sigterm) {
1119: logit("Received signal %d; terminating.",
1120: (int) received_sigterm);
1121: close_listen_socks();
1.430 djm 1122: if (options.pid_file != NULL)
1123: unlink(options.pid_file);
1.382 djm 1124: exit(received_sigterm == SIGTERM ? 0 : 255);
1.345 djm 1125: }
1126: if (ret < 0)
1127: continue;
1128:
1129: for (i = 0; i < options.max_startups; i++)
1130: if (startup_pipes[i] != -1 &&
1131: FD_ISSET(startup_pipes[i], fdset)) {
1132: /*
1133: * the read end of the pipe is ready
1134: * if the child has closed the pipe
1135: * after successful authentication
1136: * or if the child has died
1137: */
1138: close(startup_pipes[i]);
1139: startup_pipes[i] = -1;
1140: startups--;
1141: }
1142: for (i = 0; i < num_listen_socks; i++) {
1143: if (!FD_ISSET(listen_socks[i], fdset))
1144: continue;
1145: fromlen = sizeof(from);
1146: *newsock = accept(listen_socks[i],
1147: (struct sockaddr *)&from, &fromlen);
1148: if (*newsock < 0) {
1.398 markus 1149: if (errno != EINTR && errno != EWOULDBLOCK &&
1150: errno != ECONNABORTED)
1.389 djm 1151: error("accept: %.100s",
1152: strerror(errno));
1153: if (errno == EMFILE || errno == ENFILE)
1154: usleep(100 * 1000);
1.345 djm 1155: continue;
1156: }
1157: if (unset_nonblock(*newsock) == -1) {
1158: close(*newsock);
1159: continue;
1160: }
1161: if (drop_connection(startups) == 1) {
1.480 djm 1162: char *laddr = get_local_ipaddr(*newsock);
1163: char *raddr = get_peer_ipaddr(*newsock);
1164:
1165: verbose("drop connection #%d from [%s]:%d "
1166: "on [%s]:%d past MaxStartups", startups,
1167: raddr, get_peer_port(*newsock),
1168: laddr, get_local_port(*newsock));
1169: free(laddr);
1170: free(raddr);
1.345 djm 1171: close(*newsock);
1172: continue;
1173: }
1174: if (pipe(startup_p) == -1) {
1175: close(*newsock);
1176: continue;
1177: }
1178:
1179: if (rexec_flag && socketpair(AF_UNIX,
1180: SOCK_STREAM, 0, config_s) == -1) {
1181: error("reexec socketpair: %s",
1182: strerror(errno));
1183: close(*newsock);
1184: close(startup_p[0]);
1185: close(startup_p[1]);
1186: continue;
1187: }
1188:
1189: for (j = 0; j < options.max_startups; j++)
1190: if (startup_pipes[j] == -1) {
1191: startup_pipes[j] = startup_p[0];
1192: if (maxfd < startup_p[0])
1193: maxfd = startup_p[0];
1194: startups++;
1195: break;
1196: }
1197:
1198: /*
1199: * Got connection. Fork a child to handle it, unless
1200: * we are in debugging mode.
1201: */
1202: if (debug_flag) {
1203: /*
1204: * In debugging mode. Close the listening
1205: * socket, and start processing the
1206: * connection without forking.
1207: */
1208: debug("Server will not fork when running in debugging mode.");
1209: close_listen_socks();
1210: *sock_in = *newsock;
1211: *sock_out = *newsock;
1212: close(startup_p[0]);
1213: close(startup_p[1]);
1214: startup_pipe = -1;
1215: pid = getpid();
1216: if (rexec_flag) {
1.511 markus 1217: send_rexec_state(config_s[0], cfg);
1.345 djm 1218: close(config_s[0]);
1219: }
1220: break;
1221: }
1222:
1223: /*
1224: * Normal production daemon. Fork, and have
1225: * the child process the connection. The
1226: * parent continues listening.
1227: */
1228: if ((pid = fork()) == 0) {
1229: /*
1230: * Child. Close the listening and
1231: * max_startup sockets. Start using
1232: * the accepted socket. Reinitialize
1233: * logging (since our pid has changed).
1234: * We break out of the loop to handle
1235: * the connection.
1236: */
1237: startup_pipe = startup_p[1];
1238: close_startup_pipes();
1239: close_listen_socks();
1240: *sock_in = *newsock;
1241: *sock_out = *newsock;
1242: log_init(__progname,
1243: options.log_level,
1244: options.log_facility,
1245: log_stderr);
1246: if (rexec_flag)
1247: close(config_s[0]);
1248: break;
1249: }
1250:
1251: /* Parent. Stay in the loop. */
1252: if (pid < 0)
1253: error("fork: %.100s", strerror(errno));
1254: else
1255: debug("Forked child %ld.", (long)pid);
1256:
1257: close(startup_p[1]);
1258:
1259: if (rexec_flag) {
1.511 markus 1260: send_rexec_state(config_s[0], cfg);
1.345 djm 1261: close(config_s[0]);
1262: close(config_s[1]);
1263: }
1264: close(*newsock);
1265: }
1266:
1267: /* child process check (or debug mode) */
1268: if (num_listen_socks < 0)
1269: break;
1270: }
1271: }
1272:
1.466 djm 1273: /*
1274: * If IP options are supported, make sure there are none (log and
1275: * return an error if any are found). Basically we are worried about
1276: * source routing; it can be used to pretend you are somebody
1277: * (ip-address) you are not. That itself may be "almost acceptable"
1.507 djm 1278: * under certain circumstances, but rhosts authentication is useless
1.466 djm 1279: * if source routing is accepted. Notice also that if we just dropped
1280: * source routing here, the other side could use IP spoofing to do
1281: * rest of the interaction and could still bypass security. So we
1282: * exit here if we detect any IP options.
1283: */
1284: static void
1285: check_ip_options(struct ssh *ssh)
1286: {
1287: int sock_in = ssh_packet_get_connection_in(ssh);
1288: struct sockaddr_storage from;
1289: u_char opts[200];
1.475 djm 1290: socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
1.466 djm 1291: char text[sizeof(opts) * 3 + 1];
1292:
1293: memset(&from, 0, sizeof(from));
1294: if (getpeername(sock_in, (struct sockaddr *)&from,
1295: &fromlen) < 0)
1296: return;
1297: if (from.ss_family != AF_INET)
1298: return;
1299: /* XXX IPv6 options? */
1300:
1301: if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
1302: &option_size) >= 0 && option_size != 0) {
1303: text[0] = '\0';
1304: for (i = 0; i < option_size; i++)
1305: snprintf(text + i*3, sizeof(text) - i*3,
1306: " %2.2x", opts[i]);
1307: fatal("Connection from %.100s port %d with IP opts: %.800s",
1308: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
1309: }
1310: return;
1311: }
1.345 djm 1312:
1.495 djm 1313: /* Set the routing domain for this process */
1314: static void
1315: set_process_rdomain(struct ssh *ssh, const char *name)
1316: {
1317: int rtable, ortable = getrtable();
1318: const char *errstr;
1319:
1320: if (name == NULL)
1321: return; /* default */
1322:
1323: if (strcmp(name, "%D") == 0) {
1324: /* "expands" to routing domain of connection */
1325: if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
1326: return;
1327: }
1328:
1329: rtable = (int)strtonum(name, 0, 255, &errstr);
1330: if (errstr != NULL) /* Shouldn't happen */
1331: fatal("Invalid routing domain \"%s\": %s", name, errstr);
1332: if (rtable != ortable && setrtable(rtable) != 0)
1333: fatal("Unable to set routing domain %d: %s",
1334: rtable, strerror(errno));
1335: debug("%s: set routing domain %d (was %d)", __func__, rtable, ortable);
1336: }
1337:
1.508 dtucker 1338: static void
1339: accumulate_host_timing_secret(struct sshbuf *server_cfg,
1340: const struct sshkey *key)
1341: {
1342: static struct ssh_digest_ctx *ctx;
1343: u_char *hash;
1344: size_t len;
1345: struct sshbuf *buf;
1346: int r;
1347:
1348: if (ctx == NULL && (ctx = ssh_digest_start(SSH_DIGEST_SHA512)) == NULL)
1349: fatal("%s: ssh_digest_start", __func__);
1350: if (key == NULL) { /* finalize */
1351: /* add server config in case we are using agent for host keys */
1352: if (ssh_digest_update(ctx, sshbuf_ptr(server_cfg),
1353: sshbuf_len(server_cfg)) != 0)
1354: fatal("%s: ssh_digest_update", __func__);
1355: len = ssh_digest_bytes(SSH_DIGEST_SHA512);
1356: hash = xmalloc(len);
1357: if (ssh_digest_final(ctx, hash, len) != 0)
1358: fatal("%s: ssh_digest_final", __func__);
1359: options.timing_secret = PEEK_U64(hash);
1360: freezero(hash, len);
1361: ssh_digest_free(ctx);
1362: ctx = NULL;
1363: return;
1364: }
1365: if ((buf = sshbuf_new()) == NULL)
1366: fatal("%s could not allocate buffer", __func__);
1367: if ((r = sshkey_private_serialize(key, buf)) != 0)
1368: fatal("sshkey_private_serialize: %s", ssh_err(r));
1369: if (ssh_digest_update(ctx, sshbuf_ptr(buf), sshbuf_len(buf)) != 0)
1370: fatal("%s: ssh_digest_update", __func__);
1371: sshbuf_reset(buf);
1372: sshbuf_free(buf);
1373: }
1374:
1.65 deraadt 1375: /*
1376: * Main program for the daemon.
1377: */
1.2 provos 1378: int
1379: main(int ac, char **av)
1.1 deraadt 1380: {
1.466 djm 1381: struct ssh *ssh = NULL;
1.64 markus 1382: extern char *optarg;
1383: extern int optind;
1.493 djm 1384: int r, opt, on = 1, already_daemon, remote_port;
1.297 avsm 1385: int sock_in = -1, sock_out = -1, newsock = -1;
1.496 djm 1386: const char *remote_ip, *rdomain;
1.447 dtucker 1387: char *fp, *line, *laddr, *logfile = NULL;
1.345 djm 1388: int config_s[2] = { -1 , -1 };
1.493 djm 1389: u_int i, j;
1.364 markus 1390: u_int64_t ibytes, obytes;
1.362 dtucker 1391: mode_t new_umask;
1.488 markus 1392: struct sshkey *key;
1393: struct sshkey *pubkey;
1.404 markus 1394: int keytype;
1.230 provos 1395: Authctxt *authctxt;
1.498 dtucker 1396: struct connection_info *connection_info = NULL;
1.64 markus 1397:
1.465 dtucker 1398: ssh_malloc_init(); /* must be called before any mallocs */
1.138 markus 1399: /* Save argv. */
1.64 markus 1400: saved_argv = av;
1.294 djm 1401: rexec_argc = ac;
1.313 djm 1402:
1403: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1404: sanitise_stdfd();
1.64 markus 1405:
1406: /* Initialize configuration options to their default values. */
1407: initialize_server_options(&options);
1408:
1409: /* Parse command-line arguments. */
1.450 djm 1410: while ((opt = getopt(ac, av,
1411: "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1.64 markus 1412: switch (opt) {
1.75 markus 1413: case '4':
1.305 djm 1414: options.address_family = AF_INET;
1.75 markus 1415: break;
1416: case '6':
1.305 djm 1417: options.address_family = AF_INET6;
1.75 markus 1418: break;
1.64 markus 1419: case 'f':
1420: config_file_name = optarg;
1421: break;
1.373 djm 1422: case 'c':
1.493 djm 1423: servconf_add_hostcert("[command-line]", 0,
1424: &options, optarg);
1.373 djm 1425: break;
1.64 markus 1426: case 'd':
1.273 markus 1427: if (debug_flag == 0) {
1.127 markus 1428: debug_flag = 1;
1429: options.log_level = SYSLOG_LEVEL_DEBUG1;
1.273 markus 1430: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1.127 markus 1431: options.log_level++;
1.64 markus 1432: break;
1.135 markus 1433: case 'D':
1434: no_daemon_flag = 1;
1.192 lebel 1435: break;
1.399 dtucker 1436: case 'E':
1.459 dtucker 1437: logfile = optarg;
1.399 dtucker 1438: /* FALLTHROUGH */
1.192 lebel 1439: case 'e':
1440: log_stderr = 1;
1.135 markus 1441: break;
1.64 markus 1442: case 'i':
1443: inetd_flag = 1;
1444: break;
1.294 djm 1445: case 'r':
1446: rexec_flag = 0;
1447: break;
1448: case 'R':
1449: rexeced_flag = 1;
1450: inetd_flag = 1;
1451: break;
1.64 markus 1452: case 'Q':
1.158 markus 1453: /* ignored */
1.64 markus 1454: break;
1455: case 'q':
1456: options.log_level = SYSLOG_LEVEL_QUIET;
1457: break;
1458: case 'b':
1.473 naddy 1459: /* protocol 1, ignored */
1.64 markus 1460: break;
1461: case 'p':
1.75 markus 1462: options.ports_from_cmdline = 1;
1.127 markus 1463: if (options.num_ports >= MAX_PORTS) {
1464: fprintf(stderr, "too many ports.\n");
1465: exit(1);
1466: }
1.193 stevesk 1467: options.ports[options.num_ports++] = a2port(optarg);
1.366 djm 1468: if (options.ports[options.num_ports-1] <= 0) {
1.193 stevesk 1469: fprintf(stderr, "Bad port number.\n");
1470: exit(1);
1471: }
1.64 markus 1472: break;
1473: case 'g':
1.197 stevesk 1474: if ((options.login_grace_time = convtime(optarg)) == -1) {
1475: fprintf(stderr, "Invalid login grace time.\n");
1476: exit(1);
1477: }
1.64 markus 1478: break;
1479: case 'k':
1.473 naddy 1480: /* protocol 1, ignored */
1.64 markus 1481: break;
1482: case 'h':
1.493 djm 1483: servconf_add_hostkey("[command-line]", 0,
1484: &options, optarg);
1.64 markus 1485: break;
1.203 stevesk 1486: case 't':
1487: test_flag = 1;
1488: break;
1.358 dtucker 1489: case 'T':
1490: test_flag = 2;
1491: break;
1492: case 'C':
1.498 dtucker 1493: connection_info = get_connection_info(0, 0);
1.391 dtucker 1494: if (parse_server_match_testspec(connection_info,
1495: optarg) == -1)
1496: exit(1);
1.358 dtucker 1497: break;
1.125 markus 1498: case 'u':
1.438 deraadt 1499: utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1500: if (utmp_len > HOST_NAME_MAX+1) {
1.257 stevesk 1501: fprintf(stderr, "Invalid utmp length.\n");
1502: exit(1);
1503: }
1.125 markus 1504: break;
1.215 markus 1505: case 'o':
1.283 markus 1506: line = xstrdup(optarg);
1507: if (process_server_config_line(&options, line,
1.391 dtucker 1508: "command-line", 0, NULL, NULL) != 0)
1.217 deraadt 1509: exit(1);
1.402 djm 1510: free(line);
1.215 markus 1511: break;
1.64 markus 1512: case '?':
1513: default:
1.215 markus 1514: usage();
1515: break;
1.64 markus 1516: }
1517: }
1.294 djm 1518: if (rexeced_flag || inetd_flag)
1519: rexec_flag = 0;
1.355 mbalmer 1520: if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1.294 djm 1521: fatal("sshd re-exec requires execution with an absolute path");
1522: if (rexeced_flag)
1.296 djm 1523: closefrom(REEXEC_MIN_FREE_FD);
1524: else
1525: closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1.294 djm 1526:
1.426 markus 1527: #ifdef WITH_OPENSSL
1.379 djm 1528: OpenSSL_add_all_algorithms();
1.426 markus 1529: #endif
1.64 markus 1530:
1.399 dtucker 1531: /* If requested, redirect the logs to the specified logfile. */
1.459 dtucker 1532: if (logfile != NULL)
1.399 dtucker 1533: log_redirect_stderr_to(logfile);
1.75 markus 1534: /*
1535: * Force logging to stderr until we have loaded the private host
1536: * key (unless started from inetd)
1537: */
1.138 markus 1538: log_init(__progname,
1.224 markus 1539: options.log_level == SYSLOG_LEVEL_NOT_SET ?
1540: SYSLOG_LEVEL_INFO : options.log_level,
1541: options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1542: SYSLOG_FACILITY_AUTH : options.log_facility,
1.261 markus 1543: log_stderr || !inetd_flag);
1.75 markus 1544:
1.294 djm 1545: sensitive_data.have_ssh2_key = 0;
1546:
1.358 dtucker 1547: /*
1.498 dtucker 1548: * If we're not doing an extended test do not silently ignore connection
1549: * test params.
1.358 dtucker 1550: */
1.498 dtucker 1551: if (test_flag < 2 && connection_info != NULL)
1.358 dtucker 1552: fatal("Config test connection parameter (-C) provided without "
1553: "test mode (-T)");
1554:
1.294 djm 1555: /* Fetch our configuration */
1.511 markus 1556: if ((cfg = sshbuf_new()) == NULL)
1557: fatal("%s: sshbuf_new failed", __func__);
1.294 djm 1558: if (rexeced_flag)
1.511 markus 1559: recv_rexec_state(REEXEC_CONFIG_PASS_FD, cfg);
1.448 djm 1560: else if (strcasecmp(config_file_name, "none") != 0)
1.511 markus 1561: load_server_config(config_file_name, cfg);
1.294 djm 1562:
1.337 dtucker 1563: parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1.511 markus 1564: cfg, NULL);
1.64 markus 1565:
1566: /* Fill in default values for those options not explicitly set. */
1567: fill_default_server_options(&options);
1.350 dtucker 1568:
1569: /* challenge-response is implemented via keyboard interactive */
1570: if (options.challenge_response_authentication)
1571: options.kbd_interactive_authentication = 1;
1.395 djm 1572:
1573: /* Check that options are sensible */
1574: if (options.authorized_keys_command_user == NULL &&
1575: (options.authorized_keys_command != NULL &&
1576: strcasecmp(options.authorized_keys_command, "none") != 0))
1577: fatal("AuthorizedKeysCommand set without "
1578: "AuthorizedKeysCommandUser");
1.449 djm 1579: if (options.authorized_principals_command_user == NULL &&
1580: (options.authorized_principals_command != NULL &&
1581: strcasecmp(options.authorized_principals_command, "none") != 0))
1582: fatal("AuthorizedPrincipalsCommand set without "
1583: "AuthorizedPrincipalsCommandUser");
1.396 djm 1584:
1585: /*
1586: * Check whether there is any path through configured auth methods.
1587: * Unfortunately it is not possible to verify this generally before
1588: * daemonisation in the presence of Match block, but this catches
1589: * and warns for trivial misconfigurations that could break login.
1590: */
1591: if (options.num_auth_methods != 0) {
1.493 djm 1592: for (i = 0; i < options.num_auth_methods; i++) {
1593: if (auth2_methods_valid(options.auth_methods[i],
1.396 djm 1594: 1) == 0)
1595: break;
1596: }
1.493 djm 1597: if (i >= options.num_auth_methods)
1.396 djm 1598: fatal("AuthenticationMethods cannot be satisfied by "
1599: "enabled authentication methods");
1600: }
1.305 djm 1601:
1.64 markus 1602: /* Check that there are no remaining arguments. */
1603: if (optind < ac) {
1604: fprintf(stderr, "Extra argument %s.\n", av[optind]);
1605: exit(1);
1606: }
1607:
1.397 dtucker 1608: debug("sshd version %s, %s", SSH_VERSION,
1.426 markus 1609: #ifdef WITH_OPENSSL
1610: SSLeay_version(SSLEAY_VERSION)
1611: #else
1612: "without OpenSSL"
1613: #endif
1614: );
1.64 markus 1615:
1.404 markus 1616: /* load host keys */
1.329 djm 1617: sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1.488 markus 1618: sizeof(struct sshkey *));
1.404 markus 1619: sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1.488 markus 1620: sizeof(struct sshkey *));
1.404 markus 1621:
1622: if (options.host_key_agent) {
1623: if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1624: setenv(SSH_AUTHSOCKET_ENV_NAME,
1625: options.host_key_agent, 1);
1.433 djm 1626: if ((r = ssh_get_authentication_socket(NULL)) == 0)
1627: have_agent = 1;
1628: else
1629: error("Could not connect to agent \"%s\": %s",
1630: options.host_key_agent, ssh_err(r));
1.404 markus 1631: }
1.134 markus 1632:
1.217 deraadt 1633: for (i = 0; i < options.num_host_key_files; i++) {
1.430 djm 1634: if (options.host_key_files[i] == NULL)
1635: continue;
1.512 markus 1636: if ((r = sshkey_load_private(options.host_key_files[i], "",
1637: &key, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR)
1638: error("Error loading host key \"%s\": %s",
1639: options.host_key_files[i], ssh_err(r));
1640: if ((r = sshkey_load_public(options.host_key_files[i],
1641: &pubkey, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR)
1642: error("Error loading host key \"%s\": %s",
1643: options.host_key_files[i], ssh_err(r));
1.439 djm 1644: if (pubkey == NULL && key != NULL)
1.512 markus 1645: if ((r = sshkey_demote(key, &pubkey)) != 0)
1646: fatal("Could not demote key: \"%s\": %s",
1647: options.host_key_files[i], ssh_err(r));
1.179 markus 1648: sensitive_data.host_keys[i] = key;
1.404 markus 1649: sensitive_data.host_pubkeys[i] = pubkey;
1650:
1.472 markus 1651: if (key == NULL && pubkey != NULL && have_agent) {
1.443 djm 1652: debug("will rely on agent for hostkey %s",
1653: options.host_key_files[i]);
1.404 markus 1654: keytype = pubkey->type;
1655: } else if (key != NULL) {
1656: keytype = key->type;
1.511 markus 1657: accumulate_host_timing_secret(cfg, key);
1.404 markus 1658: } else {
1.195 markus 1659: error("Could not load host key: %s",
1660: options.host_key_files[i]);
1.179 markus 1661: sensitive_data.host_keys[i] = NULL;
1.404 markus 1662: sensitive_data.host_pubkeys[i] = NULL;
1.134 markus 1663: continue;
1664: }
1.404 markus 1665:
1666: switch (keytype) {
1.134 markus 1667: case KEY_RSA:
1668: case KEY_DSA:
1.378 djm 1669: case KEY_ECDSA:
1.412 markus 1670: case KEY_ED25519:
1.505 markus 1671: case KEY_XMSS:
1.441 djm 1672: if (have_agent || key != NULL)
1673: sensitive_data.have_ssh2_key = 1;
1.134 markus 1674: break;
1675: }
1.441 djm 1676: if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1677: SSH_FP_DEFAULT)) == NULL)
1678: fatal("sshkey_fingerprint failed");
1679: debug("%s host key #%d: %s %s",
1.472 markus 1680: key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp);
1.441 djm 1681: free(fp);
1.134 markus 1682: }
1.511 markus 1683: accumulate_host_timing_secret(cfg, NULL);
1.472 markus 1684: if (!sensitive_data.have_ssh2_key) {
1.264 itojun 1685: logit("sshd: no hostkeys available -- exiting.");
1.64 markus 1686: exit(1);
1687: }
1688:
1.373 djm 1689: /*
1690: * Load certificates. They are stored in an array at identical
1691: * indices to the public keys that they relate to.
1692: */
1693: sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1.488 markus 1694: sizeof(struct sshkey *));
1.373 djm 1695: for (i = 0; i < options.num_host_key_files; i++)
1696: sensitive_data.host_certificates[i] = NULL;
1697:
1698: for (i = 0; i < options.num_host_cert_files; i++) {
1.430 djm 1699: if (options.host_cert_files[i] == NULL)
1700: continue;
1.512 markus 1701: if ((r = sshkey_load_public(options.host_cert_files[i],
1702: &key, NULL)) != 0) {
1703: error("Could not load host certificate \"%s\": %s",
1704: options.host_cert_files[i], ssh_err(r));
1.373 djm 1705: continue;
1706: }
1.512 markus 1707: if (!sshkey_is_cert(key)) {
1.373 djm 1708: error("Certificate file is not a certificate: %s",
1709: options.host_cert_files[i]);
1.512 markus 1710: sshkey_free(key);
1.373 djm 1711: continue;
1712: }
1713: /* Find matching private key */
1714: for (j = 0; j < options.num_host_key_files; j++) {
1.512 markus 1715: if (sshkey_equal_public(key,
1.373 djm 1716: sensitive_data.host_keys[j])) {
1717: sensitive_data.host_certificates[j] = key;
1718: break;
1719: }
1720: }
1721: if (j >= options.num_host_key_files) {
1722: error("No matching private key for certificate: %s",
1723: options.host_cert_files[i]);
1.512 markus 1724: sshkey_free(key);
1.373 djm 1725: continue;
1726: }
1727: sensitive_data.host_certificates[j] = key;
1.493 djm 1728: debug("host certificate: #%u type %d %s", j, key->type,
1.512 markus 1729: sshkey_type(key));
1.373 djm 1730: }
1.426 markus 1731:
1.244 markus 1732: if (use_privsep) {
1733: struct stat st;
1734:
1.327 deraadt 1735: if (getpwnam(SSH_PRIVSEP_USER) == NULL)
1.244 markus 1736: fatal("Privilege separation user %s does not exist",
1737: SSH_PRIVSEP_USER);
1.500 djm 1738: endpwent();
1.244 markus 1739: if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1740: (S_ISDIR(st.st_mode) == 0))
1741: fatal("Missing privilege separation directory: %s",
1.247 stevesk 1742: _PATH_PRIVSEP_CHROOT_DIR);
1743: if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1.262 markus 1744: fatal("%s must be owned by root and not group or "
1745: "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1.358 dtucker 1746: }
1747:
1748: if (test_flag > 1) {
1.499 djm 1749: /*
1750: * If no connection info was provided by -C then use
1751: * use a blank one that will cause no predicate to match.
1752: */
1753: if (connection_info == NULL)
1754: connection_info = get_connection_info(0, 0);
1.498 dtucker 1755: parse_server_match_config(&options, connection_info);
1.358 dtucker 1756: dump_config(&options);
1.108 markus 1757: }
1.203 stevesk 1758:
1759: /* Configuration looks good, so exit if in test mode. */
1760: if (test_flag)
1761: exit(0);
1.108 markus 1762:
1.294 djm 1763: if (rexec_flag) {
1.493 djm 1764: if (rexec_argc < 0)
1765: fatal("rexec_argc %d < 0", rexec_argc);
1.329 djm 1766: rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1.493 djm 1767: for (i = 0; i < (u_int)rexec_argc; i++) {
1.294 djm 1768: debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1769: rexec_argv[i] = saved_argv[i];
1770: }
1771: rexec_argv[rexec_argc] = "-R";
1772: rexec_argv[rexec_argc + 1] = NULL;
1773: }
1.362 dtucker 1774:
1775: /* Ensure that umask disallows at least group and world write */
1776: new_umask = umask(0077) | 0022;
1777: (void) umask(new_umask);
1.294 djm 1778:
1.108 markus 1779: /* Initialize the log (it is reinitialized below in case we forked). */
1.306 dtucker 1780: if (debug_flag && (!inetd_flag || rexeced_flag))
1.64 markus 1781: log_stderr = 1;
1.138 markus 1782: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1783:
1.108 markus 1784: /*
1.478 dtucker 1785: * If not in debugging mode, not started from inetd and not already
1786: * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
1787: * terminal, and fork. The original process exits.
1.108 markus 1788: */
1.478 dtucker 1789: already_daemon = daemonized();
1790: if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
1.345 djm 1791:
1.64 markus 1792: if (daemon(0, 0) < 0)
1793: fatal("daemon() failed: %.200s", strerror(errno));
1794:
1.477 dtucker 1795: disconnect_controlling_tty();
1.64 markus 1796: }
1797: /* Reinitialize the log (because of the fork above). */
1.138 markus 1798: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1799:
1800: /* Chdir to the root directory so that the current disk can be
1801: unmounted if desired. */
1.401 dtucker 1802: if (chdir("/") == -1)
1803: error("chdir(\"/\"): %s", strerror(errno));
1.217 deraadt 1804:
1.178 markus 1805: /* ignore SIGPIPE */
1806: signal(SIGPIPE, SIG_IGN);
1.64 markus 1807:
1.345 djm 1808: /* Get a connection, either from inetd or a listening TCP socket */
1.64 markus 1809: if (inetd_flag) {
1.345 djm 1810: server_accept_inetd(&sock_in, &sock_out);
1.64 markus 1811: } else {
1.345 djm 1812: server_listen();
1.75 markus 1813:
1.201 markus 1814: signal(SIGHUP, sighup_handler);
1.345 djm 1815: signal(SIGCHLD, main_sigchld_handler);
1.201 markus 1816: signal(SIGTERM, sigterm_handler);
1817: signal(SIGQUIT, sigterm_handler);
1818:
1.345 djm 1819: /*
1820: * Write out the pid file after the sigterm handler
1821: * is setup and the listen sockets are bound
1822: */
1.479 dtucker 1823: if (options.pid_file != NULL && !debug_flag) {
1.345 djm 1824: FILE *f = fopen(options.pid_file, "w");
1.201 markus 1825:
1.270 djm 1826: if (f == NULL) {
1827: error("Couldn't create pid file \"%s\": %s",
1828: options.pid_file, strerror(errno));
1829: } else {
1.245 mpech 1830: fprintf(f, "%ld\n", (long) getpid());
1.64 markus 1831: fclose(f);
1832: }
1833: }
1834:
1.345 djm 1835: /* Accept a connection and return in a forked child */
1836: server_accept_loop(&sock_in, &sock_out,
1837: &newsock, config_s);
1.1 deraadt 1838: }
1839:
1.64 markus 1840: /* This is the child processing a new connection. */
1.288 markus 1841: setproctitle("%s", "[accepted]");
1.294 djm 1842:
1.300 markus 1843: /*
1844: * Create a new session and process group since the 4.4BSD
1845: * setlogin() affects the entire process group. We don't
1846: * want the child to be able to affect the parent.
1847: */
1848: if (!debug_flag && !inetd_flag && setsid() < 0)
1849: error("setsid: %.100s", strerror(errno));
1850:
1.294 djm 1851: if (rexec_flag) {
1852: int fd;
1853:
1.296 djm 1854: debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1855: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1856: dup2(newsock, STDIN_FILENO);
1857: dup2(STDIN_FILENO, STDOUT_FILENO);
1858: if (startup_pipe == -1)
1.296 djm 1859: close(REEXEC_STARTUP_PIPE_FD);
1.407 djm 1860: else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
1.296 djm 1861: dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
1.407 djm 1862: close(startup_pipe);
1863: startup_pipe = REEXEC_STARTUP_PIPE_FD;
1864: }
1.294 djm 1865:
1.296 djm 1866: dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
1.294 djm 1867: close(config_s[1]);
1.296 djm 1868:
1.294 djm 1869: execv(rexec_argv[0], rexec_argv);
1870:
1871: /* Reexec has failed, fall back and continue */
1872: error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
1.296 djm 1873: recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
1.294 djm 1874: log_init(__progname, options.log_level,
1875: options.log_facility, log_stderr);
1876:
1877: /* Clean up fds */
1.296 djm 1878: close(REEXEC_CONFIG_PASS_FD);
1879: newsock = sock_out = sock_in = dup(STDIN_FILENO);
1.294 djm 1880: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1881: dup2(fd, STDIN_FILENO);
1882: dup2(fd, STDOUT_FILENO);
1883: if (fd > STDERR_FILENO)
1884: close(fd);
1885: }
1.296 djm 1886: debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1887: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1888: }
1.372 djm 1889:
1890: /* Executed child processes don't need these. */
1891: fcntl(sock_out, F_SETFD, FD_CLOEXEC);
1892: fcntl(sock_in, F_SETFD, FD_CLOEXEC);
1.64 markus 1893:
1.66 markus 1894: /*
1895: * Disable the key regeneration alarm. We will not regenerate the
1896: * key since we are no longer in a position to give it to anyone. We
1897: * will not restart on SIGHUP since it no longer makes sense.
1898: */
1.64 markus 1899: alarm(0);
1900: signal(SIGALRM, SIG_DFL);
1901: signal(SIGHUP, SIG_DFL);
1902: signal(SIGTERM, SIG_DFL);
1903: signal(SIGQUIT, SIG_DFL);
1904: signal(SIGCHLD, SIG_DFL);
1.150 markus 1905:
1.66 markus 1906: /*
1907: * Register our connection. This turns encryption off because we do
1908: * not have a key.
1909: */
1.64 markus 1910: packet_set_connection(sock_in, sock_out);
1.312 markus 1911: packet_set_server();
1.466 djm 1912: ssh = active_state; /* XXX */
1.492 djm 1913:
1.466 djm 1914: check_ip_options(ssh);
1.309 djm 1915:
1.492 djm 1916: /* Prepare the channels layer */
1917: channel_init_channels(ssh);
1918: channel_set_af(ssh, options.address_family);
1919: process_permitopen(ssh, &options);
1920:
1.309 djm 1921: /* Set SO_KEEPALIVE if requested. */
1922: if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1923: setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1924: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.1 deraadt 1925:
1.466 djm 1926: if ((remote_port = ssh_remote_port(ssh)) < 0) {
1927: debug("ssh_remote_port failed");
1.310 markus 1928: cleanup_exit(255);
1929: }
1.316 dtucker 1930:
1931: /*
1.331 markus 1932: * The rest of the code depends on the fact that
1.466 djm 1933: * ssh_remote_ipaddr() caches the remote ip, even if
1.331 markus 1934: * the socket goes away.
1935: */
1.466 djm 1936: remote_ip = ssh_remote_ipaddr(ssh);
1.209 markus 1937:
1.496 djm 1938: rdomain = ssh_packet_rdomain_in(ssh);
1939:
1.64 markus 1940: /* Log the connection. */
1.447 dtucker 1941: laddr = get_local_ipaddr(sock_in);
1.497 djm 1942: verbose("Connection from %s port %d on %s port %d%s%s%s",
1.496 djm 1943: remote_ip, remote_port, laddr, ssh_local_port(ssh),
1.497 djm 1944: rdomain == NULL ? "" : " rdomain \"",
1945: rdomain == NULL ? "" : rdomain,
1946: rdomain == NULL ? "" : "\"");
1.447 dtucker 1947: free(laddr);
1.1 deraadt 1948:
1.66 markus 1949: /*
1.317 djm 1950: * We don't want to listen forever unless the other side
1.66 markus 1951: * successfully authenticates itself. So we set up an alarm which is
1952: * cleared after successful authentication. A limit of zero
1.317 djm 1953: * indicates no limit. Note that we don't set the alarm in debugging
1.66 markus 1954: * mode; it is just annoying to have the server exit just when you
1955: * are about to discover the bug.
1956: */
1.64 markus 1957: signal(SIGALRM, grace_alarm_handler);
1958: if (!debug_flag)
1959: alarm(options.login_grace_time);
1960:
1.466 djm 1961: sshd_exchange_identification(ssh, sock_in, sock_out);
1.64 markus 1962: packet_set_nonblocking();
1.1 deraadt 1963:
1.278 markus 1964: /* allocate authentication context */
1.329 djm 1965: authctxt = xcalloc(1, sizeof(*authctxt));
1.278 markus 1966:
1967: /* XXX global for cleanup, access from other modules */
1968: the_authctxt = authctxt;
1.506 djm 1969:
1970: /* Set default key authentication options */
1971: if ((auth_opts = sshauthopt_new_with_keys_defaults()) == NULL)
1972: fatal("allocation failed");
1.278 markus 1973:
1.307 otto 1974: /* prepare buffer to collect messages to display to user after login */
1.510 markus 1975: if ((loginmsg = sshbuf_new()) == NULL)
1976: fatal("%s: sshbuf_new failed", __func__);
1.374 dtucker 1977: auth_debug_reset();
1.307 otto 1978:
1.404 markus 1979: if (use_privsep) {
1.278 markus 1980: if (privsep_preauth(authctxt) == 1)
1.237 markus 1981: goto authenticated;
1.472 markus 1982: } else if (have_agent) {
1.432 djm 1983: if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
1984: error("Unable to get agent socket: %s", ssh_err(r));
1.433 djm 1985: have_agent = 0;
1.432 djm 1986: }
1987: }
1.231 provos 1988:
1.77 markus 1989: /* perform the key exchange */
1990: /* authenticate user and start session */
1.472 markus 1991: do_ssh2_kex();
1992: do_authentication2(authctxt);
1993:
1.237 markus 1994: /*
1995: * If we use privilege separation, the unprivileged child transfers
1996: * the current keystate and exits
1997: */
1998: if (use_privsep) {
1.242 mouring 1999: mm_send_keystate(pmonitor);
1.490 markus 2000: packet_clear_keys();
1.231 provos 2001: exit(0);
1.237 markus 2002: }
1.231 provos 2003:
2004: authenticated:
1.318 djm 2005: /*
2006: * Cancel the alarm we set to limit the time taken for
2007: * authentication.
2008: */
2009: alarm(0);
2010: signal(SIGALRM, SIG_DFL);
1.347 markus 2011: authctxt->authenticated = 1;
1.318 djm 2012: if (startup_pipe != -1) {
2013: close(startup_pipe);
2014: startup_pipe = -1;
2015: }
1.495 djm 2016:
2017: if (options.routing_domain != NULL)
2018: set_process_rdomain(ssh, options.routing_domain);
1.318 djm 2019:
1.234 markus 2020: /*
1.231 provos 2021: * In privilege separation, we fork another child and prepare
2022: * file descriptor passing.
2023: */
2024: if (use_privsep) {
1.237 markus 2025: privsep_postauth(authctxt);
2026: /* the monitor process [priv] will not return */
1.231 provos 2027: }
1.360 dtucker 2028:
2029: packet_set_timeout(options.client_alive_interval,
2030: options.client_alive_count_max);
1.439 djm 2031:
2032: /* Try to send all our hostkeys to the client */
1.492 djm 2033: notify_hostkeys(ssh);
1.230 provos 2034:
1.278 markus 2035: /* Start session. */
1.492 djm 2036: do_authenticated(ssh, authctxt);
1.230 provos 2037:
1.64 markus 2038: /* The connection has been terminated. */
1.434 markus 2039: packet_get_bytes(&ibytes, &obytes);
1.381 djm 2040: verbose("Transferred: sent %llu, received %llu bytes",
2041: (unsigned long long)obytes, (unsigned long long)ibytes);
1.364 markus 2042:
2043: verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
1.64 markus 2044: packet_close();
1.231 provos 2045:
2046: if (use_privsep)
2047: mm_terminate();
2048:
1.64 markus 2049: exit(0);
1.1 deraadt 2050: }
1.98 markus 2051:
1.435 markus 2052: int
1.488 markus 2053: sshd_hostkey_sign(struct sshkey *privkey, struct sshkey *pubkey,
1.512 markus 2054: u_char **signature, size_t *slenp, const u_char *data, size_t dlen,
1.488 markus 2055: const char *alg, u_int flag)
1.404 markus 2056: {
1.432 djm 2057: int r;
2058:
1.404 markus 2059: if (privkey) {
1.512 markus 2060: if (PRIVSEP(sshkey_sign(privkey, signature, slenp, data, dlen,
2061: alg, datafellows)) < 0)
1.404 markus 2062: fatal("%s: key_sign failed", __func__);
2063: } else if (use_privsep) {
1.512 markus 2064: if (mm_sshkey_sign(pubkey, signature, slenp, data, dlen,
2065: alg, datafellows) < 0)
1.404 markus 2066: fatal("%s: pubkey_sign failed", __func__);
2067: } else {
1.512 markus 2068: if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slenp,
1.461 markus 2069: data, dlen, alg, datafellows)) != 0)
1.432 djm 2070: fatal("%s: ssh_agent_sign failed: %s",
2071: __func__, ssh_err(r));
1.404 markus 2072: }
1.435 markus 2073: return 0;
1.404 markus 2074: }
2075:
1.452 djm 2076: /* SSH2 key exchange */
1.200 itojun 2077: static void
1.142 markus 2078: do_ssh2_kex(void)
1.98 markus 2079: {
1.422 markus 2080: char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
1.435 markus 2081: struct kex *kex;
1.437 markus 2082: int r;
1.102 markus 2083:
1.457 djm 2084: myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
1.513 ! djm 2085: options.kex_algorithms, datafellows);
1.457 djm 2086: myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
1.513 ! djm 2087: options.ciphers, datafellows);
1.457 djm 2088: myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
1.513 ! djm 2089: options.ciphers, datafellows);
1.457 djm 2090: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2091: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2092:
1.312 markus 2093: if (options.compression == COMP_NONE) {
1.246 markus 2094: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.470 dtucker 2095: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.102 markus 2096: }
1.400 dtucker 2097:
2098: if (options.rekey_limit || options.rekey_interval)
1.464 dtucker 2099: packet_set_rekey_limits(options.rekey_limit,
1.481 dtucker 2100: options.rekey_interval);
1.327 deraadt 2101:
1.413 djm 2102: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
1.513 ! djm 2103: list_hostkey_types(), datafellows);
1.134 markus 2104:
1.189 markus 2105: /* start key exchange */
1.437 markus 2106: if ((r = kex_setup(active_state, myproposal)) != 0)
2107: fatal("kex_setup: %s", ssh_err(r));
1.435 markus 2108: kex = active_state->kex;
1.426 markus 2109: #ifdef WITH_OPENSSL
1.263 markus 2110: kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1.292 djm 2111: kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1.468 djm 2112: kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server;
2113: kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server;
2114: kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server;
1.263 markus 2115: kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1.324 djm 2116: kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1.378 djm 2117: kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1.426 markus 2118: #endif
1.410 markus 2119: kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1.186 markus 2120: kex->server = 1;
2121: kex->client_version_string=client_version_string;
2122: kex->server_version_string=server_version_string;
1.373 djm 2123: kex->load_host_public_key=&get_hostkey_public_by_type;
2124: kex->load_host_private_key=&get_hostkey_private_by_type;
1.231 provos 2125: kex->host_key_index=&get_hostkey_index;
1.404 markus 2126: kex->sign = sshd_hostkey_sign;
1.189 markus 2127:
1.489 markus 2128: ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done);
1.187 markus 2129:
2130: session_id2 = kex->session_id;
2131: session_id2_len = kex->session_id_len;
1.129 provos 2132:
2133: #ifdef DEBUG_KEXDH
2134: /* send 1st encrypted/maced/compressed message */
2135: packet_start(SSH2_MSG_IGNORE);
2136: packet_put_cstring("markus");
2137: packet_send();
2138: packet_write_wait();
2139: #endif
1.186 markus 2140: debug("KEX done");
1.278 markus 2141: }
2142:
2143: /* server specific fatal cleanup */
2144: void
2145: cleanup_exit(int i)
2146: {
1.492 djm 2147: struct ssh *ssh = active_state; /* XXX */
2148:
1.386 djm 2149: if (the_authctxt) {
1.492 djm 2150: do_cleanup(ssh, the_authctxt);
1.423 djm 2151: if (use_privsep && privsep_is_preauth &&
2152: pmonitor != NULL && pmonitor->m_pid > 1) {
1.386 djm 2153: debug("Killing privsep child %d", pmonitor->m_pid);
2154: if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
1.388 djm 2155: errno != ESRCH)
1.386 djm 2156: error("%s: kill(%d): %s", __func__,
2157: pmonitor->m_pid, strerror(errno));
2158: }
2159: }
1.278 markus 2160: _exit(i);
1.1 deraadt 2161: }
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