Annotation of src/usr.bin/ssh/sshd.c, Revision 1.490
1.490 ! markus 1: /* $OpenBSD: sshd.c,v 1.489 2017/05/31 07:00:13 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"
1.1 deraadt 73: #include "rsa.h"
1.171 djm 74: #include "sshpty.h"
1.1 deraadt 75: #include "packet.h"
1.155 markus 76: #include "log.h"
1.343 deraadt 77: #include "buffer.h"
1.428 millert 78: #include "misc.h"
1.454 markus 79: #include "match.h"
1.1 deraadt 80: #include "servconf.h"
81: #include "uidswap.h"
1.33 markus 82: #include "compat.h"
1.155 markus 83: #include "cipher.h"
1.415 markus 84: #include "digest.h"
1.343 deraadt 85: #include "key.h"
1.98 markus 86: #include "kex.h"
87: #include "myproposal.h"
1.108 markus 88: #include "authfile.h"
1.154 markus 89: #include "pathnames.h"
1.155 markus 90: #include "atomicio.h"
91: #include "canohost.h"
1.343 deraadt 92: #include "hostfile.h"
1.155 markus 93: #include "auth.h"
1.404 markus 94: #include "authfd.h"
1.294 djm 95: #include "msg.h"
1.186 markus 96: #include "dispatch.h"
1.206 stevesk 97: #include "channels.h"
1.230 provos 98: #include "session.h"
1.231 provos 99: #include "monitor.h"
1.343 deraadt 100: #ifdef GSSAPI
101: #include "ssh-gss.h"
102: #endif
1.231 provos 103: #include "monitor_wrap.h"
1.385 djm 104: #include "ssh-sandbox.h"
1.332 stevesk 105: #include "version.h"
1.432 djm 106: #include "ssherr.h"
1.1 deraadt 107:
1.296 djm 108: /* Re-exec fds */
109: #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
110: #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
111: #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
112: #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
113:
1.138 markus 114: extern char *__progname;
115:
1.1 deraadt 116: /* Server configuration options. */
117: ServerOptions options;
118:
119: /* Name of the server configuration file. */
1.154 markus 120: char *config_file_name = _PATH_SERVER_CONFIG_FILE;
1.1 deraadt 121:
1.105 markus 122: /*
1.65 deraadt 123: * Debug mode flag. This can be set on the command line. If debug
124: * mode is enabled, extra debugging output will be sent to the system
125: * log, the daemon will not go to background, and will exit after processing
126: * the first connection.
127: */
1.1 deraadt 128: int debug_flag = 0;
129:
1.203 stevesk 130: /* Flag indicating that the daemon should only test the configuration and keys. */
131: int test_flag = 0;
132:
1.1 deraadt 133: /* Flag indicating that the daemon is being started from inetd. */
134: int inetd_flag = 0;
135:
1.135 markus 136: /* Flag indicating that sshd should not detach and become a daemon. */
137: int no_daemon_flag = 0;
138:
1.47 markus 139: /* debug goes to stderr unless inetd_flag is set */
140: int log_stderr = 0;
141:
1.1 deraadt 142: /* Saved arguments to main(). */
143: char **saved_argv;
144:
1.294 djm 145: /* re-exec */
146: int rexeced_flag = 0;
147: int rexec_flag = 1;
148: int rexec_argc = 0;
149: char **rexec_argv;
150:
1.66 markus 151: /*
1.75 markus 152: * The sockets that the server is listening; this is used in the SIGHUP
153: * signal handler.
1.66 markus 154: */
1.75 markus 155: #define MAX_LISTEN_SOCKS 16
156: int listen_socks[MAX_LISTEN_SOCKS];
157: int num_listen_socks = 0;
1.1 deraadt 158:
1.66 markus 159: /*
160: * the client's version string, passed by sshd2 in compat mode. if != NULL,
161: * sshd will skip the version-number exchange
162: */
1.61 markus 163: char *client_version_string = NULL;
1.96 markus 164: char *server_version_string = NULL;
1.1 deraadt 165:
1.404 markus 166: /* Daemon's agent connection */
1.432 djm 167: int auth_sock = -1;
1.404 markus 168: int have_agent = 0;
169:
1.66 markus 170: /*
171: * Any really sensitive data in the application is contained in this
172: * structure. The idea is that this structure could be locked into memory so
173: * that the pages do not get written into swap. However, there are some
174: * problems. The private key contains BIGNUMs, and we do not (in principle)
175: * have access to the internals of them, and locking just the structure is
176: * not very useful. Currently, memory locking is not implemented.
177: */
1.64 markus 178: struct {
1.488 markus 179: struct sshkey **host_keys; /* all private host keys */
180: struct sshkey **host_pubkeys; /* all public host keys */
181: struct sshkey **host_certificates; /* all public host certificates */
182: int have_ssh2_key;
1.1 deraadt 183: } sensitive_data;
184:
1.199 markus 185: /* This is set to true when a signal is received. */
1.212 markus 186: static volatile sig_atomic_t received_sighup = 0;
187: static volatile sig_atomic_t received_sigterm = 0;
1.1 deraadt 188:
1.96 markus 189: /* session identifier, used by RSA-auth */
1.140 markus 190: u_char session_id[16];
1.96 markus 191:
1.108 markus 192: /* same for ssh2 */
1.140 markus 193: u_char *session_id2 = NULL;
1.269 markus 194: u_int session_id2_len = 0;
1.108 markus 195:
1.125 markus 196: /* record remote hostname or ip */
1.438 deraadt 197: u_int utmp_len = HOST_NAME_MAX+1;
1.125 markus 198:
1.211 markus 199: /* options.max_startup sized array of fd ints */
200: int *startup_pipes = NULL;
201: int startup_pipe; /* in child */
202:
1.231 provos 203: /* variables used for privilege separation */
1.337 dtucker 204: int use_privsep = -1;
1.285 dtucker 205: struct monitor *pmonitor = NULL;
1.386 djm 206: int privsep_is_preauth = 1;
1.231 provos 207:
1.278 markus 208: /* global authentication context */
209: Authctxt *the_authctxt = NULL;
210:
1.337 dtucker 211: /* sshd_config buffer */
212: Buffer cfg;
213:
1.299 dtucker 214: /* message to be displayed after login */
215: Buffer loginmsg;
216:
1.1 deraadt 217: /* Prototypes for various functions defined later in this file. */
1.200 itojun 218: void destroy_sensitive_data(void);
1.231 provos 219: void demote_sensitive_data(void);
1.200 itojun 220: static void do_ssh2_kex(void);
1.129 provos 221:
1.87 markus 222: /*
1.75 markus 223: * Close all listening sockets
224: */
1.200 itojun 225: static void
1.75 markus 226: close_listen_socks(void)
227: {
228: int i;
1.250 deraadt 229:
1.75 markus 230: for (i = 0; i < num_listen_socks; i++)
231: close(listen_socks[i]);
232: num_listen_socks = -1;
233: }
234:
1.211 markus 235: static void
236: close_startup_pipes(void)
237: {
238: int i;
1.250 deraadt 239:
1.211 markus 240: if (startup_pipes)
241: for (i = 0; i < options.max_startups; i++)
242: if (startup_pipes[i] != -1)
243: close(startup_pipes[i]);
244: }
245:
1.75 markus 246: /*
1.65 deraadt 247: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
248: * the effect is to reread the configuration file (and to regenerate
249: * the server key).
250: */
1.327 deraadt 251:
252: /*ARGSUSED*/
1.200 itojun 253: static void
1.64 markus 254: sighup_handler(int sig)
1.1 deraadt 255: {
1.210 deraadt 256: int save_errno = errno;
257:
1.64 markus 258: received_sighup = 1;
259: signal(SIGHUP, sighup_handler);
1.210 deraadt 260: errno = save_errno;
1.1 deraadt 261: }
262:
1.65 deraadt 263: /*
264: * Called from the main program after receiving SIGHUP.
265: * Restarts the server.
266: */
1.200 itojun 267: static void
1.165 itojun 268: sighup_restart(void)
1.1 deraadt 269: {
1.264 itojun 270: logit("Received SIGHUP; restarting.");
1.479 dtucker 271: if (options.pid_file != NULL)
272: unlink(options.pid_file);
1.75 markus 273: close_listen_socks();
1.211 markus 274: close_startup_pipes();
1.349 dtucker 275: alarm(0); /* alarm timer persists across exec */
1.369 dtucker 276: signal(SIGHUP, SIG_IGN); /* will be restored after exec */
1.64 markus 277: execv(saved_argv[0], saved_argv);
1.264 itojun 278: logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
1.250 deraadt 279: strerror(errno));
1.64 markus 280: exit(1);
1.1 deraadt 281: }
282:
1.65 deraadt 283: /*
284: * Generic signal handler for terminating signals in the master daemon.
285: */
1.327 deraadt 286: /*ARGSUSED*/
1.200 itojun 287: static void
1.64 markus 288: sigterm_handler(int sig)
1.1 deraadt 289: {
1.199 markus 290: received_sigterm = sig;
1.1 deraadt 291: }
292:
1.65 deraadt 293: /*
294: * SIGCHLD handler. This is called whenever a child dies. This will then
1.199 markus 295: * reap any zombies left by exited children.
1.65 deraadt 296: */
1.327 deraadt 297: /*ARGSUSED*/
1.200 itojun 298: static void
1.64 markus 299: main_sigchld_handler(int sig)
1.1 deraadt 300: {
1.250 deraadt 301: int save_errno = errno;
1.239 markus 302: pid_t pid;
1.64 markus 303: int status;
1.60 deraadt 304:
1.239 markus 305: while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
306: (pid < 0 && errno == EINTR))
1.64 markus 307: ;
1.60 deraadt 308:
1.64 markus 309: signal(SIGCHLD, main_sigchld_handler);
310: errno = save_errno;
1.1 deraadt 311: }
312:
1.65 deraadt 313: /*
314: * Signal handler for the alarm after the login grace period has expired.
315: */
1.327 deraadt 316: /*ARGSUSED*/
1.200 itojun 317: static void
1.64 markus 318: grace_alarm_handler(int sig)
1.1 deraadt 319: {
1.285 dtucker 320: if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
321: kill(pmonitor->m_pid, SIGALRM);
1.394 djm 322:
323: /*
324: * Try to kill any processes that we have spawned, E.g. authorized
325: * keys command helpers.
326: */
327: if (getpgid(0) == getpid()) {
328: signal(SIGTERM, SIG_IGN);
1.416 djm 329: kill(0, SIGTERM);
1.394 djm 330: }
1.285 dtucker 331:
1.64 markus 332: /* Log error and exit. */
1.466 djm 333: sigdie("Timeout before authentication for %s port %d",
334: ssh_remote_ipaddr(active_state), ssh_remote_port(active_state));
1.62 markus 335: }
336:
1.200 itojun 337: static void
1.466 djm 338: sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out)
1.96 markus 339: {
1.311 djm 340: u_int i;
1.96 markus 341: int remote_major, remote_minor;
1.482 djm 342: char *s;
1.96 markus 343: char buf[256]; /* Must not be larger than remote_version. */
344: char remote_version[256]; /* Must be at least as big as buf. */
345:
1.482 djm 346: xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s\r\n",
1.473 naddy 347: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,
1.390 djm 348: *options.version_addendum == '\0' ? "" : " ",
1.482 djm 349: options.version_addendum);
1.96 markus 350:
1.272 markus 351: /* Send our protocol version identification. */
1.463 markus 352: if (atomicio(vwrite, sock_out, server_version_string,
1.272 markus 353: strlen(server_version_string))
354: != strlen(server_version_string)) {
1.466 djm 355: logit("Could not write ident string to %s port %d",
356: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 357: cleanup_exit(255);
1.272 markus 358: }
359:
360: /* Read other sides version identification. */
361: memset(buf, 0, sizeof(buf));
362: for (i = 0; i < sizeof(buf) - 1; i++) {
1.463 markus 363: if (atomicio(read, sock_in, &buf[i], 1) != 1) {
1.466 djm 364: logit("Did not receive identification string "
365: "from %s port %d",
366: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.278 markus 367: cleanup_exit(255);
1.96 markus 368: }
1.272 markus 369: if (buf[i] == '\r') {
370: buf[i] = 0;
371: /* Kludge for F-Secure Macintosh < 1.0.2 */
372: if (i == 12 &&
373: strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
1.96 markus 374: break;
1.272 markus 375: continue;
376: }
377: if (buf[i] == '\n') {
378: buf[i] = 0;
379: break;
1.96 markus 380: }
381: }
1.272 markus 382: buf[sizeof(buf) - 1] = 0;
383: client_version_string = xstrdup(buf);
1.96 markus 384:
385: /*
386: * Check that the versions match. In future this might accept
387: * several versions and set appropriate flags to handle them.
388: */
389: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
390: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 391: s = "Protocol mismatch.\n";
1.271 deraadt 392: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.408 djm 393: logit("Bad protocol version identification '%.100s' "
394: "from %s port %d", client_version_string,
1.466 djm 395: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.411 djm 396: close(sock_in);
397: close(sock_out);
1.278 markus 398: cleanup_exit(255);
1.96 markus 399: }
400: debug("Client protocol version %d.%d; client software version %.100s",
1.217 deraadt 401: remote_major, remote_minor, remote_version);
1.96 markus 402:
1.466 djm 403: ssh->compat = compat_datafellows(remote_version);
1.260 mickey 404:
1.466 djm 405: if ((ssh->compat & SSH_BUG_PROBE) != 0) {
406: logit("probed from %s port %d with %s. Don't panic.",
407: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
408: client_version_string);
1.278 markus 409: cleanup_exit(255);
1.260 mickey 410: }
1.466 djm 411: if ((ssh->compat & SSH_BUG_SCANNER) != 0) {
412: logit("scanned from %s port %d with %s. Don't panic.",
413: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
414: client_version_string);
1.278 markus 415: cleanup_exit(255);
1.175 deraadt 416: }
1.466 djm 417: if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) {
1.413 djm 418: logit("Client version \"%.100s\" uses unsafe RSA signature "
419: "scheme; disabling use of RSA keys", remote_version);
1.414 djm 420: }
1.466 djm 421: if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) {
1.414 djm 422: fatal("Client version \"%.100s\" uses unsafe key agreement; "
423: "refusing connection", remote_version);
424: }
1.98 markus 425:
1.102 markus 426: chop(server_version_string);
427: debug("Local version string %.200s", server_version_string);
428:
1.486 djm 429: if (remote_major != 2 ||
430: (remote_major == 1 && remote_minor != 99)) {
1.96 markus 431: s = "Protocol major versions differ.\n";
1.271 deraadt 432: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.96 markus 433: close(sock_in);
434: close(sock_out);
1.466 djm 435: logit("Protocol major versions differ for %s port %d: "
436: "%.200s vs. %.200s",
437: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1.102 markus 438: server_version_string, client_version_string);
1.278 markus 439: cleanup_exit(255);
1.96 markus 440: }
1.108 markus 441: }
442:
1.134 markus 443: /* Destroy the host and server keys. They will no longer be needed. */
1.108 markus 444: void
445: destroy_sensitive_data(void)
446: {
1.134 markus 447: int i;
448:
1.217 deraadt 449: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 450: if (sensitive_data.host_keys[i]) {
451: key_free(sensitive_data.host_keys[i]);
452: sensitive_data.host_keys[i] = NULL;
453: }
1.373 djm 454: if (sensitive_data.host_certificates[i]) {
455: key_free(sensitive_data.host_certificates[i]);
456: sensitive_data.host_certificates[i] = NULL;
457: }
1.134 markus 458: }
459: }
460:
1.231 provos 461: /* Demote private to public keys for network child */
462: void
463: demote_sensitive_data(void)
464: {
1.488 markus 465: struct sshkey *tmp;
1.231 provos 466: int i;
467:
468: for (i = 0; i < options.num_host_key_files; i++) {
469: if (sensitive_data.host_keys[i]) {
470: tmp = key_demote(sensitive_data.host_keys[i]);
471: key_free(sensitive_data.host_keys[i]);
472: sensitive_data.host_keys[i] = tmp;
473: }
1.373 djm 474: /* Certs do not need demotion */
1.231 provos 475: }
476: }
477:
1.233 markus 478: static void
1.231 provos 479: privsep_preauth_child(void)
480: {
1.253 deraadt 481: gid_t gidset[1];
1.250 deraadt 482: struct passwd *pw;
1.231 provos 483:
484: /* Enable challenge-response authentication for privilege separation */
485: privsep_challenge_enable();
1.419 djm 486:
1.420 markus 487: #ifdef GSSAPI
1.419 djm 488: /* Cache supported mechanism OIDs for later use */
489: if (options.gss_authentication)
490: ssh_gssapi_prepare_supported_oids();
1.420 markus 491: #endif
1.231 provos 492:
493: /* Demote the private keys to public keys. */
494: demote_sensitive_data();
495:
1.460 djm 496: /* Demote the child */
497: if (getuid() == 0 || geteuid() == 0) {
498: if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
499: fatal("Privilege separation user %s does not exist",
500: SSH_PRIVSEP_USER);
501: explicit_bzero(pw->pw_passwd, strlen(pw->pw_passwd));
502: endpwent();
503:
504: /* Change our root directory */
505: if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
506: fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
507: strerror(errno));
508: if (chdir("/") == -1)
509: fatal("chdir(\"/\"): %s", strerror(errno));
510:
511: /*
512: * Drop our privileges
513: * NB. Can't use setusercontext() after chroot.
514: */
515: debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
516: (u_int)pw->pw_gid);
517: gidset[0] = pw->pw_gid;
518: if (setgroups(1, gidset) < 0)
519: fatal("setgroups: %.100s", strerror(errno));
520: permanently_set_uid(pw);
521: }
1.231 provos 522: }
523:
1.278 markus 524: static int
525: privsep_preauth(Authctxt *authctxt)
1.237 markus 526: {
1.432 djm 527: int status, r;
1.237 markus 528: pid_t pid;
1.384 djm 529: struct ssh_sandbox *box = NULL;
1.237 markus 530:
531: /* Set up unprivileged child process to deal with network data */
1.242 mouring 532: pmonitor = monitor_init();
1.237 markus 533: /* Store a pointer to the kex for later rekeying */
1.434 markus 534: pmonitor->m_pkex = &active_state->kex;
1.237 markus 535:
1.393 djm 536: if (use_privsep == PRIVSEP_ON)
1.384 djm 537: box = ssh_sandbox_init();
1.237 markus 538: pid = fork();
539: if (pid == -1) {
540: fatal("fork of unprivileged child failed");
541: } else if (pid != 0) {
1.245 mpech 542: debug2("Network child is on pid %ld", (long)pid);
1.237 markus 543:
1.392 markus 544: pmonitor->m_pid = pid;
1.432 djm 545: if (have_agent) {
546: r = ssh_get_authentication_socket(&auth_sock);
547: if (r != 0) {
548: error("Could not get agent socket: %s",
549: ssh_err(r));
550: have_agent = 0;
551: }
552: }
1.384 djm 553: if (box != NULL)
554: ssh_sandbox_parent_preauth(box, pid);
1.278 markus 555: monitor_child_preauth(authctxt, pmonitor);
1.237 markus 556:
557: /* Wait for the child's exit status */
1.384 djm 558: while (waitpid(pid, &status, 0) < 0) {
1.386 djm 559: if (errno == EINTR)
560: continue;
561: pmonitor->m_pid = -1;
562: fatal("%s: waitpid: %s", __func__, strerror(errno));
1.384 djm 563: }
1.386 djm 564: privsep_is_preauth = 0;
565: pmonitor->m_pid = -1;
1.384 djm 566: if (WIFEXITED(status)) {
567: if (WEXITSTATUS(status) != 0)
568: fatal("%s: preauth child exited with status %d",
569: __func__, WEXITSTATUS(status));
570: } else if (WIFSIGNALED(status))
571: fatal("%s: preauth child terminated by signal %d",
572: __func__, WTERMSIG(status));
573: if (box != NULL)
574: ssh_sandbox_parent_finish(box);
575: return 1;
1.237 markus 576: } else {
577: /* child */
1.383 djm 578: close(pmonitor->m_sendfd);
579: close(pmonitor->m_log_recvfd);
1.237 markus 580:
1.383 djm 581: /* Arrange for logging to be sent to the monitor */
582: set_log_handler(mm_log_handler, pmonitor);
1.237 markus 583:
1.460 djm 584: privsep_preauth_child();
1.238 stevesk 585: setproctitle("%s", "[net]");
1.384 djm 586: if (box != NULL)
587: ssh_sandbox_child(box);
588:
589: return 0;
1.237 markus 590: }
591: }
592:
1.233 markus 593: static void
1.237 markus 594: privsep_postauth(Authctxt *authctxt)
1.231 provos 595: {
1.474 djm 596: if (authctxt->pw->pw_uid == 0) {
1.231 provos 597: /* File descriptor passing is broken or root login */
598: use_privsep = 0;
1.315 djm 599: goto skip;
1.231 provos 600: }
1.234 markus 601:
1.231 provos 602: /* New socket pair */
1.242 mouring 603: monitor_reinit(pmonitor);
1.231 provos 604:
1.242 mouring 605: pmonitor->m_pid = fork();
606: if (pmonitor->m_pid == -1)
1.231 provos 607: fatal("fork of unprivileged child failed");
1.242 mouring 608: else if (pmonitor->m_pid != 0) {
1.364 markus 609: verbose("User child is on pid %ld", (long)pmonitor->m_pid);
1.307 otto 610: buffer_clear(&loginmsg);
1.490 ! markus 611: monitor_clear_keystate(pmonitor);
1.242 mouring 612: monitor_child_postauth(pmonitor);
1.231 provos 613:
614: /* NEVERREACHED */
615: exit(0);
616: }
617:
1.383 djm 618: /* child */
619:
1.242 mouring 620: close(pmonitor->m_sendfd);
1.383 djm 621: pmonitor->m_sendfd = -1;
1.231 provos 622:
623: /* Demote the private keys to public keys. */
624: demote_sensitive_data();
1.354 djm 625:
1.231 provos 626: /* Drop privileges */
627: do_setusercontext(authctxt->pw);
628:
1.315 djm 629: skip:
1.231 provos 630: /* It is safe now to apply the key state */
1.242 mouring 631: monitor_apply_keystate(pmonitor);
1.312 markus 632:
633: /*
634: * Tell the packet layer that authentication was successful, since
635: * this information is not part of the key state.
636: */
637: packet_set_authenticated();
1.231 provos 638: }
639:
1.200 itojun 640: static char *
1.134 markus 641: list_hostkey_types(void)
642: {
1.223 markus 643: Buffer b;
1.281 jakob 644: const char *p;
645: char *ret;
1.134 markus 646: int i;
1.488 markus 647: struct sshkey *key;
1.223 markus 648:
649: buffer_init(&b);
1.217 deraadt 650: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 651: key = sensitive_data.host_keys[i];
1.443 djm 652: if (key == NULL)
1.404 markus 653: key = sensitive_data.host_pubkeys[i];
1.472 markus 654: if (key == NULL)
1.134 markus 655: continue;
1.454 markus 656: /* Check that the key is accepted in HostkeyAlgorithms */
657: if (match_pattern_list(sshkey_ssh_name(key),
658: options.hostkeyalgorithms, 0) != 1) {
659: debug3("%s: %s key not permitted by HostkeyAlgorithms",
660: __func__, sshkey_ssh_name(key));
661: continue;
662: }
1.214 deraadt 663: switch (key->type) {
1.134 markus 664: case KEY_RSA:
665: case KEY_DSA:
1.378 djm 666: case KEY_ECDSA:
1.412 markus 667: case KEY_ED25519:
1.223 markus 668: if (buffer_len(&b) > 0)
669: buffer_append(&b, ",", 1);
670: p = key_ssh_name(key);
671: buffer_append(&b, p, strlen(p));
1.461 markus 672:
673: /* for RSA we also support SHA2 signatures */
674: if (key->type == KEY_RSA) {
675: p = ",rsa-sha2-512,rsa-sha2-256";
676: buffer_append(&b, p, strlen(p));
677: }
1.134 markus 678: break;
679: }
1.373 djm 680: /* If the private key has a cert peer, then list that too */
681: key = sensitive_data.host_certificates[i];
682: if (key == NULL)
683: continue;
684: switch (key->type) {
685: case KEY_RSA_CERT:
686: case KEY_DSA_CERT:
1.378 djm 687: case KEY_ECDSA_CERT:
1.412 markus 688: case KEY_ED25519_CERT:
1.373 djm 689: if (buffer_len(&b) > 0)
690: buffer_append(&b, ",", 1);
691: p = key_ssh_name(key);
692: buffer_append(&b, p, strlen(p));
693: break;
694: }
1.134 markus 695: }
1.467 djm 696: if ((ret = sshbuf_dup_string(&b)) == NULL)
697: fatal("%s: sshbuf_dup_string failed", __func__);
1.223 markus 698: buffer_free(&b);
1.281 jakob 699: debug("list_hostkey_types: %s", ret);
700: return ret;
1.134 markus 701: }
702:
1.488 markus 703: static struct sshkey *
1.440 djm 704: get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
1.134 markus 705: {
706: int i;
1.488 markus 707: struct sshkey *key;
1.250 deraadt 708:
1.217 deraadt 709: for (i = 0; i < options.num_host_key_files; i++) {
1.375 djm 710: switch (type) {
711: case KEY_RSA_CERT:
712: case KEY_DSA_CERT:
1.378 djm 713: case KEY_ECDSA_CERT:
1.412 markus 714: case KEY_ED25519_CERT:
1.373 djm 715: key = sensitive_data.host_certificates[i];
1.375 djm 716: break;
717: default:
1.373 djm 718: key = sensitive_data.host_keys[i];
1.404 markus 719: if (key == NULL && !need_private)
720: key = sensitive_data.host_pubkeys[i];
1.375 djm 721: break;
722: }
1.440 djm 723: if (key != NULL && key->type == type &&
724: (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
1.373 djm 725: return need_private ?
726: sensitive_data.host_keys[i] : key;
1.134 markus 727: }
728: return NULL;
1.96 markus 729: }
730:
1.488 markus 731: struct sshkey *
1.440 djm 732: get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 733: {
1.440 djm 734: return get_hostkey_by_type(type, nid, 0, ssh);
1.373 djm 735: }
736:
1.488 markus 737: struct sshkey *
1.440 djm 738: get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
1.373 djm 739: {
1.440 djm 740: return get_hostkey_by_type(type, nid, 1, ssh);
1.373 djm 741: }
742:
1.488 markus 743: struct sshkey *
1.231 provos 744: get_hostkey_by_index(int ind)
745: {
746: if (ind < 0 || ind >= options.num_host_key_files)
747: return (NULL);
748: return (sensitive_data.host_keys[ind]);
749: }
750:
1.488 markus 751: struct sshkey *
1.435 markus 752: get_hostkey_public_by_index(int ind, struct ssh *ssh)
1.404 markus 753: {
754: if (ind < 0 || ind >= options.num_host_key_files)
755: return (NULL);
756: return (sensitive_data.host_pubkeys[ind]);
757: }
758:
1.231 provos 759: int
1.488 markus 760: get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh)
1.231 provos 761: {
762: int i;
1.250 deraadt 763:
1.231 provos 764: for (i = 0; i < options.num_host_key_files; i++) {
1.373 djm 765: if (key_is_cert(key)) {
1.442 djm 766: if (key == sensitive_data.host_certificates[i] ||
767: (compare && sensitive_data.host_certificates[i] &&
768: sshkey_equal(key,
769: sensitive_data.host_certificates[i])))
1.373 djm 770: return (i);
771: } else {
1.442 djm 772: if (key == sensitive_data.host_keys[i] ||
773: (compare && sensitive_data.host_keys[i] &&
774: sshkey_equal(key, sensitive_data.host_keys[i])))
1.373 djm 775: return (i);
1.442 djm 776: if (key == sensitive_data.host_pubkeys[i] ||
777: (compare && sensitive_data.host_pubkeys[i] &&
778: sshkey_equal(key, sensitive_data.host_pubkeys[i])))
1.404 markus 779: return (i);
1.373 djm 780: }
1.231 provos 781: }
782: return (-1);
783: }
784:
1.439 djm 785: /* Inform the client of all hostkeys */
786: static void
787: notify_hostkeys(struct ssh *ssh)
788: {
789: struct sshbuf *buf;
790: struct sshkey *key;
791: int i, nkeys, r;
792: char *fp;
1.446 dtucker 793:
794: /* Some clients cannot cope with the hostkeys message, skip those. */
795: if (datafellows & SSH_BUG_HOSTKEYS)
796: return;
1.439 djm 797:
798: if ((buf = sshbuf_new()) == NULL)
799: fatal("%s: sshbuf_new", __func__);
800: for (i = nkeys = 0; i < options.num_host_key_files; i++) {
801: key = get_hostkey_public_by_index(i, ssh);
802: if (key == NULL || key->type == KEY_UNSPEC ||
1.472 markus 803: sshkey_is_cert(key))
1.439 djm 804: continue;
805: fp = sshkey_fingerprint(key, options.fingerprint_hash,
806: SSH_FP_DEFAULT);
807: debug3("%s: key %d: %s %s", __func__, i,
808: sshkey_ssh_name(key), fp);
809: free(fp);
1.442 djm 810: if (nkeys == 0) {
811: packet_start(SSH2_MSG_GLOBAL_REQUEST);
1.444 djm 812: packet_put_cstring("hostkeys-00@openssh.com");
1.442 djm 813: packet_put_char(0); /* want-reply */
814: }
815: sshbuf_reset(buf);
816: if ((r = sshkey_putb(key, buf)) != 0)
1.439 djm 817: fatal("%s: couldn't put hostkey %d: %s",
818: __func__, i, ssh_err(r));
1.442 djm 819: packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
1.439 djm 820: nkeys++;
821: }
1.442 djm 822: debug3("%s: sent %d hostkeys", __func__, nkeys);
1.439 djm 823: if (nkeys == 0)
824: fatal("%s: no hostkeys", __func__);
825: packet_send();
1.442 djm 826: sshbuf_free(buf);
1.439 djm 827: }
828:
1.124 markus 829: /*
830: * returns 1 if connection should be dropped, 0 otherwise.
831: * dropping starts at connection #max_startups_begin with a probability
832: * of (max_startups_rate/100). the probability increases linearly until
833: * all connections are dropped for startups > max_startups
834: */
1.200 itojun 835: static int
1.124 markus 836: drop_connection(int startups)
837: {
1.303 mickey 838: int p, r;
1.124 markus 839:
840: if (startups < options.max_startups_begin)
841: return 0;
842: if (startups >= options.max_startups)
843: return 1;
844: if (options.max_startups_rate == 100)
845: return 1;
846:
847: p = 100 - options.max_startups_rate;
848: p *= startups - options.max_startups_begin;
1.303 mickey 849: p /= options.max_startups - options.max_startups_begin;
1.124 markus 850: p += options.max_startups_rate;
1.356 djm 851: r = arc4random_uniform(100);
1.124 markus 852:
1.304 djm 853: debug("drop_connection: p %d, r %d", p, r);
1.124 markus 854: return (r < p) ? 1 : 0;
855: }
856:
1.215 markus 857: static void
858: usage(void)
859: {
1.290 markus 860: fprintf(stderr, "%s, %s\n",
1.426 markus 861: SSH_VERSION,
862: #ifdef WITH_OPENSSL
863: SSLeay_version(SSLEAY_VERSION)
864: #else
865: "without OpenSSL"
866: #endif
867: );
1.289 markus 868: fprintf(stderr,
1.473 naddy 869: "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n"
1.399 dtucker 870: " [-E log_file] [-f config_file] [-g login_grace_time]\n"
1.473 naddy 871: " [-h host_key_file] [-o option] [-p port] [-u len]\n"
1.289 markus 872: );
1.215 markus 873: exit(1);
874: }
875:
1.294 djm 876: static void
1.467 djm 877: send_rexec_state(int fd, struct sshbuf *conf)
1.294 djm 878: {
1.467 djm 879: struct sshbuf *m;
880: int r;
1.294 djm 881:
1.467 djm 882: debug3("%s: entering fd = %d config len %zu", __func__, fd,
883: sshbuf_len(conf));
1.294 djm 884:
885: /*
886: * Protocol from reexec master to child:
887: * string configuration
888: */
1.467 djm 889: if ((m = sshbuf_new()) == NULL)
890: fatal("%s: sshbuf_new failed", __func__);
891: if ((r = sshbuf_put_stringb(m, conf)) != 0)
892: fatal("%s: buffer error: %s", __func__, ssh_err(r));
893: if (ssh_msg_send(fd, 0, m) == -1)
1.294 djm 894: fatal("%s: ssh_msg_send failed", __func__);
895:
1.467 djm 896: sshbuf_free(m);
1.294 djm 897:
898: debug3("%s: done", __func__);
899: }
900:
901: static void
902: recv_rexec_state(int fd, Buffer *conf)
903: {
904: Buffer m;
905: char *cp;
906: u_int len;
907:
908: debug3("%s: entering fd = %d", __func__, fd);
909:
910: buffer_init(&m);
911:
912: if (ssh_msg_recv(fd, &m) == -1)
913: fatal("%s: ssh_msg_recv failed", __func__);
914: if (buffer_get_char(&m) != 0)
915: fatal("%s: rexec version mismatch", __func__);
916:
917: cp = buffer_get_string(&m, &len);
918: if (conf != NULL)
1.469 djm 919: buffer_append(conf, cp, len);
1.402 djm 920: free(cp);
1.294 djm 921:
922: buffer_free(&m);
923:
924: debug3("%s: done", __func__);
925: }
926:
1.345 djm 927: /* Accept a connection from inetd */
928: static void
929: server_accept_inetd(int *sock_in, int *sock_out)
930: {
931: int fd;
932:
933: startup_pipe = -1;
934: if (rexeced_flag) {
935: close(REEXEC_CONFIG_PASS_FD);
936: *sock_in = *sock_out = dup(STDIN_FILENO);
937: if (!debug_flag) {
938: startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
939: close(REEXEC_STARTUP_PIPE_FD);
940: }
941: } else {
942: *sock_in = dup(STDIN_FILENO);
943: *sock_out = dup(STDOUT_FILENO);
944: }
945: /*
946: * We intentionally do not close the descriptors 0, 1, and 2
947: * as our code for setting the descriptors won't work if
948: * ttyfd happens to be one of those.
949: */
950: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
951: dup2(fd, STDIN_FILENO);
952: dup2(fd, STDOUT_FILENO);
1.403 dtucker 953: if (!log_stderr)
954: dup2(fd, STDERR_FILENO);
955: if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1.345 djm 956: close(fd);
957: }
958: debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
959: }
960:
961: /*
962: * Listen for TCP connections
963: */
964: static void
965: server_listen(void)
966: {
967: int ret, listen_sock, on = 1;
968: struct addrinfo *ai;
969: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
970:
971: for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
972: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
973: continue;
974: if (num_listen_socks >= MAX_LISTEN_SOCKS)
975: fatal("Too many listen sockets. "
976: "Enlarge MAX_LISTEN_SOCKS");
977: if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
978: ntop, sizeof(ntop), strport, sizeof(strport),
979: NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
980: error("getnameinfo failed: %.100s",
1.352 dtucker 981: ssh_gai_strerror(ret));
1.345 djm 982: continue;
983: }
984: /* Create socket for listening. */
1.370 dtucker 985: listen_sock = socket(ai->ai_family, ai->ai_socktype,
986: ai->ai_protocol);
1.345 djm 987: if (listen_sock < 0) {
988: /* kernel may not support ipv6 */
989: verbose("socket: %.100s", strerror(errno));
990: continue;
991: }
992: if (set_nonblock(listen_sock) == -1) {
1.483 djm 993: close(listen_sock);
994: continue;
995: }
996: if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) {
997: verbose("socket: CLOEXEC: %s", strerror(errno));
1.345 djm 998: close(listen_sock);
999: continue;
1000: }
1001: /*
1002: * Set socket options.
1003: * Allow local port reuse in TIME_WAIT.
1004: */
1005: if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1006: &on, sizeof(on)) == -1)
1007: error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1008:
1009: debug("Bind to port %s on %s.", strport, ntop);
1010:
1011: /* Bind the socket to the desired port. */
1012: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1013: error("Bind to port %s on %s failed: %.200s.",
1014: strport, ntop, strerror(errno));
1015: close(listen_sock);
1016: continue;
1017: }
1018: listen_socks[num_listen_socks] = listen_sock;
1019: num_listen_socks++;
1020:
1021: /* Start listening on the port. */
1022: if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1023: fatal("listen on [%s]:%s: %.100s",
1024: ntop, strport, strerror(errno));
1025: logit("Server listening on %s port %s.", ntop, strport);
1026: }
1027: freeaddrinfo(options.listen_addrs);
1028:
1029: if (!num_listen_socks)
1030: fatal("Cannot bind any address.");
1031: }
1032:
1033: /*
1034: * The main TCP accept loop. Note that, for the non-debug case, returns
1035: * from this function are in a forked subprocess.
1036: */
1037: static void
1038: server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1039: {
1040: fd_set *fdset;
1041: int i, j, ret, maxfd;
1.472 markus 1042: int startups = 0;
1.345 djm 1043: int startup_p[2] = { -1 , -1 };
1044: struct sockaddr_storage from;
1045: socklen_t fromlen;
1046: pid_t pid;
1047:
1048: /* setup fd set for accept */
1049: fdset = NULL;
1050: maxfd = 0;
1051: for (i = 0; i < num_listen_socks; i++)
1052: if (listen_socks[i] > maxfd)
1053: maxfd = listen_socks[i];
1054: /* pipes connected to unauthenticated childs */
1055: startup_pipes = xcalloc(options.max_startups, sizeof(int));
1056: for (i = 0; i < options.max_startups; i++)
1057: startup_pipes[i] = -1;
1058:
1059: /*
1060: * Stay listening for connections until the system crashes or
1061: * the daemon is killed with a signal.
1062: */
1063: for (;;) {
1064: if (received_sighup)
1065: sighup_restart();
1.462 mmcc 1066: free(fdset);
1.458 deraadt 1067: fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1.345 djm 1068: sizeof(fd_mask));
1069:
1070: for (i = 0; i < num_listen_socks; i++)
1071: FD_SET(listen_socks[i], fdset);
1072: for (i = 0; i < options.max_startups; i++)
1073: if (startup_pipes[i] != -1)
1074: FD_SET(startup_pipes[i], fdset);
1075:
1076: /* Wait in select until there is a connection. */
1077: ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1078: if (ret < 0 && errno != EINTR)
1079: error("select: %.100s", strerror(errno));
1080: if (received_sigterm) {
1081: logit("Received signal %d; terminating.",
1082: (int) received_sigterm);
1083: close_listen_socks();
1.430 djm 1084: if (options.pid_file != NULL)
1085: unlink(options.pid_file);
1.382 djm 1086: exit(received_sigterm == SIGTERM ? 0 : 255);
1.345 djm 1087: }
1088: if (ret < 0)
1089: continue;
1090:
1091: for (i = 0; i < options.max_startups; i++)
1092: if (startup_pipes[i] != -1 &&
1093: FD_ISSET(startup_pipes[i], fdset)) {
1094: /*
1095: * the read end of the pipe is ready
1096: * if the child has closed the pipe
1097: * after successful authentication
1098: * or if the child has died
1099: */
1100: close(startup_pipes[i]);
1101: startup_pipes[i] = -1;
1102: startups--;
1103: }
1104: for (i = 0; i < num_listen_socks; i++) {
1105: if (!FD_ISSET(listen_socks[i], fdset))
1106: continue;
1107: fromlen = sizeof(from);
1108: *newsock = accept(listen_socks[i],
1109: (struct sockaddr *)&from, &fromlen);
1110: if (*newsock < 0) {
1.398 markus 1111: if (errno != EINTR && errno != EWOULDBLOCK &&
1112: errno != ECONNABORTED)
1.389 djm 1113: error("accept: %.100s",
1114: strerror(errno));
1115: if (errno == EMFILE || errno == ENFILE)
1116: usleep(100 * 1000);
1.345 djm 1117: continue;
1118: }
1119: if (unset_nonblock(*newsock) == -1) {
1120: close(*newsock);
1121: continue;
1122: }
1123: if (drop_connection(startups) == 1) {
1.480 djm 1124: char *laddr = get_local_ipaddr(*newsock);
1125: char *raddr = get_peer_ipaddr(*newsock);
1126:
1127: verbose("drop connection #%d from [%s]:%d "
1128: "on [%s]:%d past MaxStartups", startups,
1129: raddr, get_peer_port(*newsock),
1130: laddr, get_local_port(*newsock));
1131: free(laddr);
1132: free(raddr);
1.345 djm 1133: close(*newsock);
1134: continue;
1135: }
1136: if (pipe(startup_p) == -1) {
1137: close(*newsock);
1138: continue;
1139: }
1140:
1141: if (rexec_flag && socketpair(AF_UNIX,
1142: SOCK_STREAM, 0, config_s) == -1) {
1143: error("reexec socketpair: %s",
1144: strerror(errno));
1145: close(*newsock);
1146: close(startup_p[0]);
1147: close(startup_p[1]);
1148: continue;
1149: }
1150:
1151: for (j = 0; j < options.max_startups; j++)
1152: if (startup_pipes[j] == -1) {
1153: startup_pipes[j] = startup_p[0];
1154: if (maxfd < startup_p[0])
1155: maxfd = startup_p[0];
1156: startups++;
1157: break;
1158: }
1159:
1160: /*
1161: * Got connection. Fork a child to handle it, unless
1162: * we are in debugging mode.
1163: */
1164: if (debug_flag) {
1165: /*
1166: * In debugging mode. Close the listening
1167: * socket, and start processing the
1168: * connection without forking.
1169: */
1170: debug("Server will not fork when running in debugging mode.");
1171: close_listen_socks();
1172: *sock_in = *newsock;
1173: *sock_out = *newsock;
1174: close(startup_p[0]);
1175: close(startup_p[1]);
1176: startup_pipe = -1;
1177: pid = getpid();
1178: if (rexec_flag) {
1179: send_rexec_state(config_s[0],
1180: &cfg);
1181: close(config_s[0]);
1182: }
1183: break;
1184: }
1185:
1186: /*
1187: * Normal production daemon. Fork, and have
1188: * the child process the connection. The
1189: * parent continues listening.
1190: */
1191: if ((pid = fork()) == 0) {
1192: /*
1193: * Child. Close the listening and
1194: * max_startup sockets. Start using
1195: * the accepted socket. Reinitialize
1196: * logging (since our pid has changed).
1197: * We break out of the loop to handle
1198: * the connection.
1199: */
1200: startup_pipe = startup_p[1];
1201: close_startup_pipes();
1202: close_listen_socks();
1203: *sock_in = *newsock;
1204: *sock_out = *newsock;
1205: log_init(__progname,
1206: options.log_level,
1207: options.log_facility,
1208: log_stderr);
1209: if (rexec_flag)
1210: close(config_s[0]);
1211: break;
1212: }
1213:
1214: /* Parent. Stay in the loop. */
1215: if (pid < 0)
1216: error("fork: %.100s", strerror(errno));
1217: else
1218: debug("Forked child %ld.", (long)pid);
1219:
1220: close(startup_p[1]);
1221:
1222: if (rexec_flag) {
1223: send_rexec_state(config_s[0], &cfg);
1224: close(config_s[0]);
1225: close(config_s[1]);
1226: }
1227: close(*newsock);
1228: }
1229:
1230: /* child process check (or debug mode) */
1231: if (num_listen_socks < 0)
1232: break;
1233: }
1234: }
1235:
1.466 djm 1236: /*
1237: * If IP options are supported, make sure there are none (log and
1238: * return an error if any are found). Basically we are worried about
1239: * source routing; it can be used to pretend you are somebody
1240: * (ip-address) you are not. That itself may be "almost acceptable"
1241: * under certain circumstances, but rhosts autentication is useless
1242: * if source routing is accepted. Notice also that if we just dropped
1243: * source routing here, the other side could use IP spoofing to do
1244: * rest of the interaction and could still bypass security. So we
1245: * exit here if we detect any IP options.
1246: */
1247: static void
1248: check_ip_options(struct ssh *ssh)
1249: {
1250: int sock_in = ssh_packet_get_connection_in(ssh);
1251: struct sockaddr_storage from;
1252: u_char opts[200];
1.475 djm 1253: socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
1.466 djm 1254: char text[sizeof(opts) * 3 + 1];
1255:
1256: memset(&from, 0, sizeof(from));
1257: if (getpeername(sock_in, (struct sockaddr *)&from,
1258: &fromlen) < 0)
1259: return;
1260: if (from.ss_family != AF_INET)
1261: return;
1262: /* XXX IPv6 options? */
1263:
1264: if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
1265: &option_size) >= 0 && option_size != 0) {
1266: text[0] = '\0';
1267: for (i = 0; i < option_size; i++)
1268: snprintf(text + i*3, sizeof(text) - i*3,
1269: " %2.2x", opts[i]);
1270: fatal("Connection from %.100s port %d with IP opts: %.800s",
1271: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
1272: }
1273: return;
1274: }
1.345 djm 1275:
1.65 deraadt 1276: /*
1277: * Main program for the daemon.
1278: */
1.2 provos 1279: int
1280: main(int ac, char **av)
1.1 deraadt 1281: {
1.466 djm 1282: struct ssh *ssh = NULL;
1.64 markus 1283: extern char *optarg;
1284: extern int optind;
1.478 dtucker 1285: int r, opt, i, j, on = 1, already_daemon;
1.297 avsm 1286: int sock_in = -1, sock_out = -1, newsock = -1;
1.64 markus 1287: const char *remote_ip;
1288: int remote_port;
1.447 dtucker 1289: char *fp, *line, *laddr, *logfile = NULL;
1.345 djm 1290: int config_s[2] = { -1 , -1 };
1.396 djm 1291: u_int n;
1.364 markus 1292: u_int64_t ibytes, obytes;
1.362 dtucker 1293: mode_t new_umask;
1.488 markus 1294: struct sshkey *key;
1295: struct sshkey *pubkey;
1.404 markus 1296: int keytype;
1.230 provos 1297: Authctxt *authctxt;
1.391 dtucker 1298: struct connection_info *connection_info = get_connection_info(0, 0);
1.64 markus 1299:
1.465 dtucker 1300: ssh_malloc_init(); /* must be called before any mallocs */
1.138 markus 1301: /* Save argv. */
1.64 markus 1302: saved_argv = av;
1.294 djm 1303: rexec_argc = ac;
1.313 djm 1304:
1305: /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1306: sanitise_stdfd();
1.64 markus 1307:
1308: /* Initialize configuration options to their default values. */
1309: initialize_server_options(&options);
1310:
1311: /* Parse command-line arguments. */
1.450 djm 1312: while ((opt = getopt(ac, av,
1313: "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1.64 markus 1314: switch (opt) {
1.75 markus 1315: case '4':
1.305 djm 1316: options.address_family = AF_INET;
1.75 markus 1317: break;
1318: case '6':
1.305 djm 1319: options.address_family = AF_INET6;
1.75 markus 1320: break;
1.64 markus 1321: case 'f':
1322: config_file_name = optarg;
1323: break;
1.373 djm 1324: case 'c':
1325: if (options.num_host_cert_files >= MAX_HOSTCERTS) {
1326: fprintf(stderr, "too many host certificates.\n");
1327: exit(1);
1328: }
1329: options.host_cert_files[options.num_host_cert_files++] =
1330: derelativise_path(optarg);
1331: break;
1.64 markus 1332: case 'd':
1.273 markus 1333: if (debug_flag == 0) {
1.127 markus 1334: debug_flag = 1;
1335: options.log_level = SYSLOG_LEVEL_DEBUG1;
1.273 markus 1336: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1.127 markus 1337: options.log_level++;
1.64 markus 1338: break;
1.135 markus 1339: case 'D':
1340: no_daemon_flag = 1;
1.192 lebel 1341: break;
1.399 dtucker 1342: case 'E':
1.459 dtucker 1343: logfile = optarg;
1.399 dtucker 1344: /* FALLTHROUGH */
1.192 lebel 1345: case 'e':
1346: log_stderr = 1;
1.135 markus 1347: break;
1.64 markus 1348: case 'i':
1349: inetd_flag = 1;
1350: break;
1.294 djm 1351: case 'r':
1352: rexec_flag = 0;
1353: break;
1354: case 'R':
1355: rexeced_flag = 1;
1356: inetd_flag = 1;
1357: break;
1.64 markus 1358: case 'Q':
1.158 markus 1359: /* ignored */
1.64 markus 1360: break;
1361: case 'q':
1362: options.log_level = SYSLOG_LEVEL_QUIET;
1363: break;
1364: case 'b':
1.473 naddy 1365: /* protocol 1, ignored */
1.64 markus 1366: break;
1367: case 'p':
1.75 markus 1368: options.ports_from_cmdline = 1;
1.127 markus 1369: if (options.num_ports >= MAX_PORTS) {
1370: fprintf(stderr, "too many ports.\n");
1371: exit(1);
1372: }
1.193 stevesk 1373: options.ports[options.num_ports++] = a2port(optarg);
1.366 djm 1374: if (options.ports[options.num_ports-1] <= 0) {
1.193 stevesk 1375: fprintf(stderr, "Bad port number.\n");
1376: exit(1);
1377: }
1.64 markus 1378: break;
1379: case 'g':
1.197 stevesk 1380: if ((options.login_grace_time = convtime(optarg)) == -1) {
1381: fprintf(stderr, "Invalid login grace time.\n");
1382: exit(1);
1383: }
1.64 markus 1384: break;
1385: case 'k':
1.473 naddy 1386: /* protocol 1, ignored */
1.64 markus 1387: break;
1388: case 'h':
1.134 markus 1389: if (options.num_host_key_files >= MAX_HOSTKEYS) {
1390: fprintf(stderr, "too many host keys.\n");
1391: exit(1);
1392: }
1.371 djm 1393: options.host_key_files[options.num_host_key_files++] =
1394: derelativise_path(optarg);
1.64 markus 1395: break;
1.203 stevesk 1396: case 't':
1397: test_flag = 1;
1398: break;
1.358 dtucker 1399: case 'T':
1400: test_flag = 2;
1401: break;
1402: case 'C':
1.391 dtucker 1403: if (parse_server_match_testspec(connection_info,
1404: optarg) == -1)
1405: exit(1);
1.358 dtucker 1406: break;
1.125 markus 1407: case 'u':
1.438 deraadt 1408: utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1409: if (utmp_len > HOST_NAME_MAX+1) {
1.257 stevesk 1410: fprintf(stderr, "Invalid utmp length.\n");
1411: exit(1);
1412: }
1.125 markus 1413: break;
1.215 markus 1414: case 'o':
1.283 markus 1415: line = xstrdup(optarg);
1416: if (process_server_config_line(&options, line,
1.391 dtucker 1417: "command-line", 0, NULL, NULL) != 0)
1.217 deraadt 1418: exit(1);
1.402 djm 1419: free(line);
1.215 markus 1420: break;
1.64 markus 1421: case '?':
1422: default:
1.215 markus 1423: usage();
1424: break;
1.64 markus 1425: }
1426: }
1.294 djm 1427: if (rexeced_flag || inetd_flag)
1428: rexec_flag = 0;
1.355 mbalmer 1429: if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1.294 djm 1430: fatal("sshd re-exec requires execution with an absolute path");
1431: if (rexeced_flag)
1.296 djm 1432: closefrom(REEXEC_MIN_FREE_FD);
1433: else
1434: closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1.294 djm 1435:
1.426 markus 1436: #ifdef WITH_OPENSSL
1.379 djm 1437: OpenSSL_add_all_algorithms();
1.426 markus 1438: #endif
1.64 markus 1439:
1.399 dtucker 1440: /* If requested, redirect the logs to the specified logfile. */
1.459 dtucker 1441: if (logfile != NULL)
1.399 dtucker 1442: log_redirect_stderr_to(logfile);
1.75 markus 1443: /*
1444: * Force logging to stderr until we have loaded the private host
1445: * key (unless started from inetd)
1446: */
1.138 markus 1447: log_init(__progname,
1.224 markus 1448: options.log_level == SYSLOG_LEVEL_NOT_SET ?
1449: SYSLOG_LEVEL_INFO : options.log_level,
1450: options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1451: SYSLOG_FACILITY_AUTH : options.log_facility,
1.261 markus 1452: log_stderr || !inetd_flag);
1.75 markus 1453:
1.294 djm 1454: sensitive_data.have_ssh2_key = 0;
1455:
1.358 dtucker 1456: /*
1457: * If we're doing an extended config test, make sure we have all of
1458: * the parameters we need. If we're not doing an extended test,
1459: * do not silently ignore connection test params.
1460: */
1.391 dtucker 1461: if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0)
1.358 dtucker 1462: fatal("user, host and addr are all required when testing "
1463: "Match configs");
1.391 dtucker 1464: if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0)
1.358 dtucker 1465: fatal("Config test connection parameter (-C) provided without "
1466: "test mode (-T)");
1467:
1.294 djm 1468: /* Fetch our configuration */
1469: buffer_init(&cfg);
1470: if (rexeced_flag)
1.296 djm 1471: recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
1.448 djm 1472: else if (strcasecmp(config_file_name, "none") != 0)
1.294 djm 1473: load_server_config(config_file_name, &cfg);
1474:
1.337 dtucker 1475: parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1.391 dtucker 1476: &cfg, NULL);
1.64 markus 1477:
1478: /* Fill in default values for those options not explicitly set. */
1479: fill_default_server_options(&options);
1.350 dtucker 1480:
1481: /* challenge-response is implemented via keyboard interactive */
1482: if (options.challenge_response_authentication)
1483: options.kbd_interactive_authentication = 1;
1.395 djm 1484:
1485: /* Check that options are sensible */
1486: if (options.authorized_keys_command_user == NULL &&
1487: (options.authorized_keys_command != NULL &&
1488: strcasecmp(options.authorized_keys_command, "none") != 0))
1489: fatal("AuthorizedKeysCommand set without "
1490: "AuthorizedKeysCommandUser");
1.449 djm 1491: if (options.authorized_principals_command_user == NULL &&
1492: (options.authorized_principals_command != NULL &&
1493: strcasecmp(options.authorized_principals_command, "none") != 0))
1494: fatal("AuthorizedPrincipalsCommand set without "
1495: "AuthorizedPrincipalsCommandUser");
1.396 djm 1496:
1497: /*
1498: * Check whether there is any path through configured auth methods.
1499: * Unfortunately it is not possible to verify this generally before
1500: * daemonisation in the presence of Match block, but this catches
1501: * and warns for trivial misconfigurations that could break login.
1502: */
1503: if (options.num_auth_methods != 0) {
1504: for (n = 0; n < options.num_auth_methods; n++) {
1505: if (auth2_methods_valid(options.auth_methods[n],
1506: 1) == 0)
1507: break;
1508: }
1509: if (n >= options.num_auth_methods)
1510: fatal("AuthenticationMethods cannot be satisfied by "
1511: "enabled authentication methods");
1512: }
1.305 djm 1513:
1.370 dtucker 1514: /* set default channel AF */
1.305 djm 1515: channel_set_af(options.address_family);
1.64 markus 1516:
1517: /* Check that there are no remaining arguments. */
1518: if (optind < ac) {
1519: fprintf(stderr, "Extra argument %s.\n", av[optind]);
1520: exit(1);
1521: }
1522:
1.397 dtucker 1523: debug("sshd version %s, %s", SSH_VERSION,
1.426 markus 1524: #ifdef WITH_OPENSSL
1525: SSLeay_version(SSLEAY_VERSION)
1526: #else
1527: "without OpenSSL"
1528: #endif
1529: );
1.64 markus 1530:
1.404 markus 1531: /* load host keys */
1.329 djm 1532: sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1.488 markus 1533: sizeof(struct sshkey *));
1.404 markus 1534: sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1.488 markus 1535: sizeof(struct sshkey *));
1.404 markus 1536:
1537: if (options.host_key_agent) {
1538: if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1539: setenv(SSH_AUTHSOCKET_ENV_NAME,
1540: options.host_key_agent, 1);
1.433 djm 1541: if ((r = ssh_get_authentication_socket(NULL)) == 0)
1542: have_agent = 1;
1543: else
1544: error("Could not connect to agent \"%s\": %s",
1545: options.host_key_agent, ssh_err(r));
1.404 markus 1546: }
1.134 markus 1547:
1.217 deraadt 1548: for (i = 0; i < options.num_host_key_files; i++) {
1.430 djm 1549: if (options.host_key_files[i] == NULL)
1550: continue;
1.179 markus 1551: key = key_load_private(options.host_key_files[i], "", NULL);
1.404 markus 1552: pubkey = key_load_public(options.host_key_files[i], NULL);
1.484 djm 1553:
1.439 djm 1554: if (pubkey == NULL && key != NULL)
1555: pubkey = key_demote(key);
1.179 markus 1556: sensitive_data.host_keys[i] = key;
1.404 markus 1557: sensitive_data.host_pubkeys[i] = pubkey;
1558:
1.472 markus 1559: if (key == NULL && pubkey != NULL && have_agent) {
1.443 djm 1560: debug("will rely on agent for hostkey %s",
1561: options.host_key_files[i]);
1.404 markus 1562: keytype = pubkey->type;
1563: } else if (key != NULL) {
1564: keytype = key->type;
1565: } else {
1.195 markus 1566: error("Could not load host key: %s",
1567: options.host_key_files[i]);
1.179 markus 1568: sensitive_data.host_keys[i] = NULL;
1.404 markus 1569: sensitive_data.host_pubkeys[i] = NULL;
1.134 markus 1570: continue;
1571: }
1.404 markus 1572:
1573: switch (keytype) {
1.134 markus 1574: case KEY_RSA:
1575: case KEY_DSA:
1.378 djm 1576: case KEY_ECDSA:
1.412 markus 1577: case KEY_ED25519:
1.441 djm 1578: if (have_agent || key != NULL)
1579: sensitive_data.have_ssh2_key = 1;
1.134 markus 1580: break;
1581: }
1.441 djm 1582: if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1583: SSH_FP_DEFAULT)) == NULL)
1584: fatal("sshkey_fingerprint failed");
1585: debug("%s host key #%d: %s %s",
1.472 markus 1586: key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp);
1.441 djm 1587: free(fp);
1.134 markus 1588: }
1.472 markus 1589: if (!sensitive_data.have_ssh2_key) {
1.264 itojun 1590: logit("sshd: no hostkeys available -- exiting.");
1.64 markus 1591: exit(1);
1592: }
1593:
1.373 djm 1594: /*
1595: * Load certificates. They are stored in an array at identical
1596: * indices to the public keys that they relate to.
1597: */
1598: sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1.488 markus 1599: sizeof(struct sshkey *));
1.373 djm 1600: for (i = 0; i < options.num_host_key_files; i++)
1601: sensitive_data.host_certificates[i] = NULL;
1602:
1603: for (i = 0; i < options.num_host_cert_files; i++) {
1.430 djm 1604: if (options.host_cert_files[i] == NULL)
1605: continue;
1.373 djm 1606: key = key_load_public(options.host_cert_files[i], NULL);
1607: if (key == NULL) {
1608: error("Could not load host certificate: %s",
1609: options.host_cert_files[i]);
1610: continue;
1611: }
1612: if (!key_is_cert(key)) {
1613: error("Certificate file is not a certificate: %s",
1614: options.host_cert_files[i]);
1615: key_free(key);
1616: continue;
1617: }
1618: /* Find matching private key */
1619: for (j = 0; j < options.num_host_key_files; j++) {
1620: if (key_equal_public(key,
1621: sensitive_data.host_keys[j])) {
1622: sensitive_data.host_certificates[j] = key;
1623: break;
1624: }
1625: }
1626: if (j >= options.num_host_key_files) {
1627: error("No matching private key for certificate: %s",
1628: options.host_cert_files[i]);
1629: key_free(key);
1630: continue;
1631: }
1632: sensitive_data.host_certificates[j] = key;
1633: debug("host certificate: #%d type %d %s", j, key->type,
1634: key_type(key));
1635: }
1.426 markus 1636:
1.244 markus 1637: if (use_privsep) {
1638: struct stat st;
1639:
1.327 deraadt 1640: if (getpwnam(SSH_PRIVSEP_USER) == NULL)
1.244 markus 1641: fatal("Privilege separation user %s does not exist",
1642: SSH_PRIVSEP_USER);
1643: if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1644: (S_ISDIR(st.st_mode) == 0))
1645: fatal("Missing privilege separation directory: %s",
1.247 stevesk 1646: _PATH_PRIVSEP_CHROOT_DIR);
1647: if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1.262 markus 1648: fatal("%s must be owned by root and not group or "
1649: "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1.358 dtucker 1650: }
1651:
1652: if (test_flag > 1) {
1.391 dtucker 1653: if (server_match_spec_complete(connection_info) == 1)
1654: parse_server_match_config(&options, connection_info);
1.358 dtucker 1655: dump_config(&options);
1.108 markus 1656: }
1.203 stevesk 1657:
1658: /* Configuration looks good, so exit if in test mode. */
1659: if (test_flag)
1660: exit(0);
1.108 markus 1661:
1.294 djm 1662: if (rexec_flag) {
1.329 djm 1663: rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1.294 djm 1664: for (i = 0; i < rexec_argc; i++) {
1665: debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1666: rexec_argv[i] = saved_argv[i];
1667: }
1668: rexec_argv[rexec_argc] = "-R";
1669: rexec_argv[rexec_argc + 1] = NULL;
1670: }
1.362 dtucker 1671:
1672: /* Ensure that umask disallows at least group and world write */
1673: new_umask = umask(0077) | 0022;
1674: (void) umask(new_umask);
1.294 djm 1675:
1.108 markus 1676: /* Initialize the log (it is reinitialized below in case we forked). */
1.306 dtucker 1677: if (debug_flag && (!inetd_flag || rexeced_flag))
1.64 markus 1678: log_stderr = 1;
1.138 markus 1679: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1680:
1.108 markus 1681: /*
1.478 dtucker 1682: * If not in debugging mode, not started from inetd and not already
1683: * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
1684: * terminal, and fork. The original process exits.
1.108 markus 1685: */
1.478 dtucker 1686: already_daemon = daemonized();
1687: if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
1.345 djm 1688:
1.64 markus 1689: if (daemon(0, 0) < 0)
1690: fatal("daemon() failed: %.200s", strerror(errno));
1691:
1.477 dtucker 1692: disconnect_controlling_tty();
1.64 markus 1693: }
1694: /* Reinitialize the log (because of the fork above). */
1.138 markus 1695: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1696:
1697: /* Chdir to the root directory so that the current disk can be
1698: unmounted if desired. */
1.401 dtucker 1699: if (chdir("/") == -1)
1700: error("chdir(\"/\"): %s", strerror(errno));
1.217 deraadt 1701:
1.178 markus 1702: /* ignore SIGPIPE */
1703: signal(SIGPIPE, SIG_IGN);
1.64 markus 1704:
1.345 djm 1705: /* Get a connection, either from inetd or a listening TCP socket */
1.64 markus 1706: if (inetd_flag) {
1.345 djm 1707: server_accept_inetd(&sock_in, &sock_out);
1.64 markus 1708: } else {
1.345 djm 1709: server_listen();
1.75 markus 1710:
1.201 markus 1711: signal(SIGHUP, sighup_handler);
1.345 djm 1712: signal(SIGCHLD, main_sigchld_handler);
1.201 markus 1713: signal(SIGTERM, sigterm_handler);
1714: signal(SIGQUIT, sigterm_handler);
1715:
1.345 djm 1716: /*
1717: * Write out the pid file after the sigterm handler
1718: * is setup and the listen sockets are bound
1719: */
1.479 dtucker 1720: if (options.pid_file != NULL && !debug_flag) {
1.345 djm 1721: FILE *f = fopen(options.pid_file, "w");
1.201 markus 1722:
1.270 djm 1723: if (f == NULL) {
1724: error("Couldn't create pid file \"%s\": %s",
1725: options.pid_file, strerror(errno));
1726: } else {
1.245 mpech 1727: fprintf(f, "%ld\n", (long) getpid());
1.64 markus 1728: fclose(f);
1729: }
1730: }
1731:
1.345 djm 1732: /* Accept a connection and return in a forked child */
1733: server_accept_loop(&sock_in, &sock_out,
1734: &newsock, config_s);
1.1 deraadt 1735: }
1736:
1.64 markus 1737: /* This is the child processing a new connection. */
1.288 markus 1738: setproctitle("%s", "[accepted]");
1.294 djm 1739:
1.300 markus 1740: /*
1741: * Create a new session and process group since the 4.4BSD
1742: * setlogin() affects the entire process group. We don't
1743: * want the child to be able to affect the parent.
1744: */
1745: if (!debug_flag && !inetd_flag && setsid() < 0)
1746: error("setsid: %.100s", strerror(errno));
1747:
1.294 djm 1748: if (rexec_flag) {
1749: int fd;
1750:
1.296 djm 1751: debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1752: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1753: dup2(newsock, STDIN_FILENO);
1754: dup2(STDIN_FILENO, STDOUT_FILENO);
1755: if (startup_pipe == -1)
1.296 djm 1756: close(REEXEC_STARTUP_PIPE_FD);
1.407 djm 1757: else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
1.296 djm 1758: dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
1.407 djm 1759: close(startup_pipe);
1760: startup_pipe = REEXEC_STARTUP_PIPE_FD;
1761: }
1.294 djm 1762:
1.296 djm 1763: dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
1.294 djm 1764: close(config_s[1]);
1.296 djm 1765:
1.294 djm 1766: execv(rexec_argv[0], rexec_argv);
1767:
1768: /* Reexec has failed, fall back and continue */
1769: error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
1.296 djm 1770: recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
1.294 djm 1771: log_init(__progname, options.log_level,
1772: options.log_facility, log_stderr);
1773:
1774: /* Clean up fds */
1.296 djm 1775: close(REEXEC_CONFIG_PASS_FD);
1776: newsock = sock_out = sock_in = dup(STDIN_FILENO);
1.294 djm 1777: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1778: dup2(fd, STDIN_FILENO);
1779: dup2(fd, STDOUT_FILENO);
1780: if (fd > STDERR_FILENO)
1781: close(fd);
1782: }
1.296 djm 1783: debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1784: sock_in, sock_out, newsock, startup_pipe, config_s[0]);
1.294 djm 1785: }
1.372 djm 1786:
1787: /* Executed child processes don't need these. */
1788: fcntl(sock_out, F_SETFD, FD_CLOEXEC);
1789: fcntl(sock_in, F_SETFD, FD_CLOEXEC);
1.64 markus 1790:
1.66 markus 1791: /*
1792: * Disable the key regeneration alarm. We will not regenerate the
1793: * key since we are no longer in a position to give it to anyone. We
1794: * will not restart on SIGHUP since it no longer makes sense.
1795: */
1.64 markus 1796: alarm(0);
1797: signal(SIGALRM, SIG_DFL);
1798: signal(SIGHUP, SIG_DFL);
1799: signal(SIGTERM, SIG_DFL);
1800: signal(SIGQUIT, SIG_DFL);
1801: signal(SIGCHLD, SIG_DFL);
1.150 markus 1802:
1.66 markus 1803: /*
1804: * Register our connection. This turns encryption off because we do
1805: * not have a key.
1806: */
1.64 markus 1807: packet_set_connection(sock_in, sock_out);
1.312 markus 1808: packet_set_server();
1.466 djm 1809: ssh = active_state; /* XXX */
1810: check_ip_options(ssh);
1.309 djm 1811:
1812: /* Set SO_KEEPALIVE if requested. */
1813: if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1814: setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1815: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.1 deraadt 1816:
1.466 djm 1817: if ((remote_port = ssh_remote_port(ssh)) < 0) {
1818: debug("ssh_remote_port failed");
1.310 markus 1819: cleanup_exit(255);
1820: }
1.316 dtucker 1821:
1822: /*
1.331 markus 1823: * The rest of the code depends on the fact that
1.466 djm 1824: * ssh_remote_ipaddr() caches the remote ip, even if
1.331 markus 1825: * the socket goes away.
1826: */
1.466 djm 1827: remote_ip = ssh_remote_ipaddr(ssh);
1.209 markus 1828:
1.64 markus 1829: /* Log the connection. */
1.447 dtucker 1830: laddr = get_local_ipaddr(sock_in);
1.409 djm 1831: verbose("Connection from %s port %d on %s port %d",
1.466 djm 1832: remote_ip, remote_port, laddr, ssh_local_port(ssh));
1.447 dtucker 1833: free(laddr);
1.1 deraadt 1834:
1.66 markus 1835: /*
1.317 djm 1836: * We don't want to listen forever unless the other side
1.66 markus 1837: * successfully authenticates itself. So we set up an alarm which is
1838: * cleared after successful authentication. A limit of zero
1.317 djm 1839: * indicates no limit. Note that we don't set the alarm in debugging
1.66 markus 1840: * mode; it is just annoying to have the server exit just when you
1841: * are about to discover the bug.
1842: */
1.64 markus 1843: signal(SIGALRM, grace_alarm_handler);
1844: if (!debug_flag)
1845: alarm(options.login_grace_time);
1846:
1.466 djm 1847: sshd_exchange_identification(ssh, sock_in, sock_out);
1.64 markus 1848: packet_set_nonblocking();
1.1 deraadt 1849:
1.278 markus 1850: /* allocate authentication context */
1.329 djm 1851: authctxt = xcalloc(1, sizeof(*authctxt));
1.278 markus 1852:
1853: /* XXX global for cleanup, access from other modules */
1854: the_authctxt = authctxt;
1855:
1.307 otto 1856: /* prepare buffer to collect messages to display to user after login */
1857: buffer_init(&loginmsg);
1.374 dtucker 1858: auth_debug_reset();
1.307 otto 1859:
1.404 markus 1860: if (use_privsep) {
1.278 markus 1861: if (privsep_preauth(authctxt) == 1)
1.237 markus 1862: goto authenticated;
1.472 markus 1863: } else if (have_agent) {
1.432 djm 1864: if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
1865: error("Unable to get agent socket: %s", ssh_err(r));
1.433 djm 1866: have_agent = 0;
1.432 djm 1867: }
1868: }
1.231 provos 1869:
1.77 markus 1870: /* perform the key exchange */
1871: /* authenticate user and start session */
1.472 markus 1872: do_ssh2_kex();
1873: do_authentication2(authctxt);
1874:
1.237 markus 1875: /*
1876: * If we use privilege separation, the unprivileged child transfers
1877: * the current keystate and exits
1878: */
1879: if (use_privsep) {
1.242 mouring 1880: mm_send_keystate(pmonitor);
1.490 ! markus 1881: packet_clear_keys();
1.231 provos 1882: exit(0);
1.237 markus 1883: }
1.231 provos 1884:
1885: authenticated:
1.318 djm 1886: /*
1887: * Cancel the alarm we set to limit the time taken for
1888: * authentication.
1889: */
1890: alarm(0);
1891: signal(SIGALRM, SIG_DFL);
1.347 markus 1892: authctxt->authenticated = 1;
1.318 djm 1893: if (startup_pipe != -1) {
1894: close(startup_pipe);
1895: startup_pipe = -1;
1896: }
1897:
1.234 markus 1898: /*
1.231 provos 1899: * In privilege separation, we fork another child and prepare
1900: * file descriptor passing.
1901: */
1902: if (use_privsep) {
1.237 markus 1903: privsep_postauth(authctxt);
1904: /* the monitor process [priv] will not return */
1.231 provos 1905: }
1.360 dtucker 1906:
1907: packet_set_timeout(options.client_alive_interval,
1908: options.client_alive_count_max);
1.439 djm 1909:
1910: /* Try to send all our hostkeys to the client */
1.472 markus 1911: notify_hostkeys(active_state);
1.230 provos 1912:
1.278 markus 1913: /* Start session. */
1.230 provos 1914: do_authenticated(authctxt);
1915:
1.64 markus 1916: /* The connection has been terminated. */
1.434 markus 1917: packet_get_bytes(&ibytes, &obytes);
1.381 djm 1918: verbose("Transferred: sent %llu, received %llu bytes",
1919: (unsigned long long)obytes, (unsigned long long)ibytes);
1.364 markus 1920:
1921: verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
1.64 markus 1922: packet_close();
1.231 provos 1923:
1924: if (use_privsep)
1925: mm_terminate();
1926:
1.64 markus 1927: exit(0);
1.1 deraadt 1928: }
1.98 markus 1929:
1.435 markus 1930: int
1.488 markus 1931: sshd_hostkey_sign(struct sshkey *privkey, struct sshkey *pubkey,
1932: u_char **signature, size_t *slen, const u_char *data, size_t dlen,
1933: const char *alg, u_int flag)
1.404 markus 1934: {
1.432 djm 1935: int r;
1.435 markus 1936: u_int xxx_slen, xxx_dlen = dlen;
1.432 djm 1937:
1.404 markus 1938: if (privkey) {
1.461 markus 1939: if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen,
1940: alg) < 0))
1.404 markus 1941: fatal("%s: key_sign failed", __func__);
1.435 markus 1942: if (slen)
1943: *slen = xxx_slen;
1.404 markus 1944: } else if (use_privsep) {
1.461 markus 1945: if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen,
1946: alg) < 0)
1.404 markus 1947: fatal("%s: pubkey_sign failed", __func__);
1.435 markus 1948: if (slen)
1949: *slen = xxx_slen;
1.404 markus 1950: } else {
1.435 markus 1951: if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
1.461 markus 1952: data, dlen, alg, datafellows)) != 0)
1.432 djm 1953: fatal("%s: ssh_agent_sign failed: %s",
1954: __func__, ssh_err(r));
1.404 markus 1955: }
1.435 markus 1956: return 0;
1.404 markus 1957: }
1958:
1.452 djm 1959: /* SSH2 key exchange */
1.200 itojun 1960: static void
1.142 markus 1961: do_ssh2_kex(void)
1.98 markus 1962: {
1.422 markus 1963: char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
1.435 markus 1964: struct kex *kex;
1.437 markus 1965: int r;
1.102 markus 1966:
1.457 djm 1967: myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
1968: options.kex_algorithms);
1969: myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
1970: options.ciphers);
1971: myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
1972: options.ciphers);
1973: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1974: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1975:
1.312 markus 1976: if (options.compression == COMP_NONE) {
1.246 markus 1977: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.470 dtucker 1978: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.102 markus 1979: }
1.400 dtucker 1980:
1981: if (options.rekey_limit || options.rekey_interval)
1.464 dtucker 1982: packet_set_rekey_limits(options.rekey_limit,
1.481 dtucker 1983: options.rekey_interval);
1.327 deraadt 1984:
1.413 djm 1985: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
1986: list_hostkey_types());
1.134 markus 1987:
1.189 markus 1988: /* start key exchange */
1.437 markus 1989: if ((r = kex_setup(active_state, myproposal)) != 0)
1990: fatal("kex_setup: %s", ssh_err(r));
1.435 markus 1991: kex = active_state->kex;
1.426 markus 1992: #ifdef WITH_OPENSSL
1.263 markus 1993: kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1.292 djm 1994: kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1.468 djm 1995: kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server;
1996: kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server;
1997: kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server;
1.263 markus 1998: kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1.324 djm 1999: kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1.378 djm 2000: kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1.426 markus 2001: #endif
1.410 markus 2002: kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1.186 markus 2003: kex->server = 1;
2004: kex->client_version_string=client_version_string;
2005: kex->server_version_string=server_version_string;
1.373 djm 2006: kex->load_host_public_key=&get_hostkey_public_by_type;
2007: kex->load_host_private_key=&get_hostkey_private_by_type;
1.231 provos 2008: kex->host_key_index=&get_hostkey_index;
1.404 markus 2009: kex->sign = sshd_hostkey_sign;
1.189 markus 2010:
1.489 markus 2011: ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done);
1.187 markus 2012:
2013: session_id2 = kex->session_id;
2014: session_id2_len = kex->session_id_len;
1.129 provos 2015:
2016: #ifdef DEBUG_KEXDH
2017: /* send 1st encrypted/maced/compressed message */
2018: packet_start(SSH2_MSG_IGNORE);
2019: packet_put_cstring("markus");
2020: packet_send();
2021: packet_write_wait();
2022: #endif
1.186 markus 2023: debug("KEX done");
1.278 markus 2024: }
2025:
2026: /* server specific fatal cleanup */
2027: void
2028: cleanup_exit(int i)
2029: {
1.386 djm 2030: if (the_authctxt) {
1.278 markus 2031: do_cleanup(the_authctxt);
1.423 djm 2032: if (use_privsep && privsep_is_preauth &&
2033: pmonitor != NULL && pmonitor->m_pid > 1) {
1.386 djm 2034: debug("Killing privsep child %d", pmonitor->m_pid);
2035: if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
1.388 djm 2036: errno != ESRCH)
1.386 djm 2037: error("%s: kill(%d): %s", __func__,
2038: pmonitor->m_pid, strerror(errno));
2039: }
2040: }
1.278 markus 2041: _exit(i);
1.1 deraadt 2042: }