Annotation of src/usr.bin/ssh/sshd.c, Revision 1.294
1.86 markus 1: /*
1.65 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.126 deraadt 5: * This program is the ssh daemon. It listens for connections from clients,
6: * and performs authentication, executes use commands or shell, and forwards
1.65 deraadt 7: * information to/from the application to the user client over an encrypted
1.126 deraadt 8: * connection. This can also handle forwarding of X11, TCP/IP, and
9: * authentication agent connections.
1.98 markus 10: *
1.126 deraadt 11: * As far as I am concerned, the code I have written for this software
12: * can be used freely for any purpose. Any derived versions of this
13: * software must be clearly marked as such, and if the derived work is
14: * incompatible with the protocol description in the RFC file, it must be
15: * called by a name other than "ssh" or "Secure Shell".
16: *
17: * SSH2 implementation:
1.231 provos 18: * Privilege Separation:
1.126 deraadt 19: *
1.231 provos 20: * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
21: * Copyright (c) 2002 Niels Provos. All rights reserved.
1.126 deraadt 22: *
23: * Redistribution and use in source and binary forms, with or without
24: * modification, are permitted provided that the following conditions
25: * are met:
26: * 1. Redistributions of source code must retain the above copyright
27: * notice, this list of conditions and the following disclaimer.
28: * 2. Redistributions in binary form must reproduce the above copyright
29: * notice, this list of conditions and the following disclaimer in the
30: * documentation and/or other materials provided with the distribution.
31: *
32: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
33: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
34: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
35: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
36: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
38: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
39: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
41: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.65 deraadt 42: */
1.1 deraadt 43:
44: #include "includes.h"
1.294 ! djm 45: RCSID("$OpenBSD: sshd.c,v 1.293 2004/06/14 01:44:39 djm Exp $");
1.1 deraadt 46:
1.155 markus 47: #include <openssl/dh.h>
48: #include <openssl/bn.h>
1.226 markus 49: #include <openssl/md5.h>
1.231 provos 50: #include <openssl/rand.h>
1.155 markus 51:
52: #include "ssh.h"
53: #include "ssh1.h"
54: #include "ssh2.h"
1.1 deraadt 55: #include "xmalloc.h"
56: #include "rsa.h"
1.171 djm 57: #include "sshpty.h"
1.1 deraadt 58: #include "packet.h"
1.155 markus 59: #include "log.h"
1.1 deraadt 60: #include "servconf.h"
61: #include "uidswap.h"
1.33 markus 62: #include "compat.h"
1.96 markus 63: #include "buffer.h"
1.294 ! djm 64: #include "bufaux.h"
1.155 markus 65: #include "cipher.h"
1.98 markus 66: #include "kex.h"
1.96 markus 67: #include "key.h"
1.129 provos 68: #include "dh.h"
1.98 markus 69: #include "myproposal.h"
1.108 markus 70: #include "authfile.h"
1.154 markus 71: #include "pathnames.h"
1.155 markus 72: #include "atomicio.h"
73: #include "canohost.h"
74: #include "auth.h"
75: #include "misc.h"
1.294 ! djm 76: #include "msg.h"
1.186 markus 77: #include "dispatch.h"
1.206 stevesk 78: #include "channels.h"
1.230 provos 79: #include "session.h"
1.231 provos 80: #include "monitor_mm.h"
81: #include "monitor.h"
82: #include "monitor_wrap.h"
83: #include "monitor_fdpass.h"
1.1 deraadt 84:
85: #ifdef LIBWRAP
86: #include <tcpd.h>
87: #include <syslog.h>
88: int allow_severity = LOG_INFO;
89: int deny_severity = LOG_WARNING;
90: #endif /* LIBWRAP */
91:
92: #ifndef O_NOCTTY
93: #define O_NOCTTY 0
94: #endif
95:
1.138 markus 96: extern char *__progname;
97:
1.1 deraadt 98: /* Server configuration options. */
99: ServerOptions options;
100:
101: /* Name of the server configuration file. */
1.154 markus 102: char *config_file_name = _PATH_SERVER_CONFIG_FILE;
1.1 deraadt 103:
1.105 markus 104: /*
1.75 markus 105: * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
106: * Default value is AF_UNSPEC means both IPv4 and IPv6.
107: */
108: int IPv4or6 = AF_UNSPEC;
109:
1.65 deraadt 110: /*
111: * Debug mode flag. This can be set on the command line. If debug
112: * mode is enabled, extra debugging output will be sent to the system
113: * log, the daemon will not go to background, and will exit after processing
114: * the first connection.
115: */
1.1 deraadt 116: int debug_flag = 0;
117:
1.203 stevesk 118: /* Flag indicating that the daemon should only test the configuration and keys. */
119: int test_flag = 0;
120:
1.1 deraadt 121: /* Flag indicating that the daemon is being started from inetd. */
122: int inetd_flag = 0;
123:
1.135 markus 124: /* Flag indicating that sshd should not detach and become a daemon. */
125: int no_daemon_flag = 0;
126:
1.47 markus 127: /* debug goes to stderr unless inetd_flag is set */
128: int log_stderr = 0;
129:
1.1 deraadt 130: /* Saved arguments to main(). */
131: char **saved_argv;
132:
1.294 ! djm 133: /* re-exec */
! 134: int rexeced_flag = 0;
! 135: int rexec_flag = 1;
! 136: int rexec_argc = 0;
! 137: char **rexec_argv;
! 138:
1.66 markus 139: /*
1.75 markus 140: * The sockets that the server is listening; this is used in the SIGHUP
141: * signal handler.
1.66 markus 142: */
1.75 markus 143: #define MAX_LISTEN_SOCKS 16
144: int listen_socks[MAX_LISTEN_SOCKS];
145: int num_listen_socks = 0;
1.1 deraadt 146:
1.66 markus 147: /*
148: * the client's version string, passed by sshd2 in compat mode. if != NULL,
149: * sshd will skip the version-number exchange
150: */
1.61 markus 151: char *client_version_string = NULL;
1.96 markus 152: char *server_version_string = NULL;
1.1 deraadt 153:
1.189 markus 154: /* for rekeying XXX fixme */
155: Kex *xxx_kex;
156:
1.66 markus 157: /*
158: * Any really sensitive data in the application is contained in this
159: * structure. The idea is that this structure could be locked into memory so
160: * that the pages do not get written into swap. However, there are some
161: * problems. The private key contains BIGNUMs, and we do not (in principle)
162: * have access to the internals of them, and locking just the structure is
163: * not very useful. Currently, memory locking is not implemented.
164: */
1.64 markus 165: struct {
1.174 deraadt 166: Key *server_key; /* ephemeral server key */
1.134 markus 167: Key *ssh1_host_key; /* ssh1 host key */
168: Key **host_keys; /* all private host keys */
169: int have_ssh1_key;
170: int have_ssh2_key;
1.169 markus 171: u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
1.1 deraadt 172: } sensitive_data;
173:
1.66 markus 174: /*
1.151 markus 175: * Flag indicating whether the RSA server key needs to be regenerated.
176: * Is set in the SIGALRM handler and cleared when the key is regenerated.
1.66 markus 177: */
1.212 markus 178: static volatile sig_atomic_t key_do_regen = 0;
1.1 deraadt 179:
1.199 markus 180: /* This is set to true when a signal is received. */
1.212 markus 181: static volatile sig_atomic_t received_sighup = 0;
182: static volatile sig_atomic_t received_sigterm = 0;
1.1 deraadt 183:
1.96 markus 184: /* session identifier, used by RSA-auth */
1.140 markus 185: u_char session_id[16];
1.96 markus 186:
1.108 markus 187: /* same for ssh2 */
1.140 markus 188: u_char *session_id2 = NULL;
1.269 markus 189: u_int session_id2_len = 0;
1.108 markus 190:
1.125 markus 191: /* record remote hostname or ip */
1.140 markus 192: u_int utmp_len = MAXHOSTNAMELEN;
1.125 markus 193:
1.211 markus 194: /* options.max_startup sized array of fd ints */
195: int *startup_pipes = NULL;
196: int startup_pipe; /* in child */
197:
1.231 provos 198: /* variables used for privilege separation */
1.263 markus 199: int use_privsep;
1.285 dtucker 200: struct monitor *pmonitor = NULL;
1.231 provos 201:
1.278 markus 202: /* global authentication context */
203: Authctxt *the_authctxt = NULL;
204:
1.1 deraadt 205: /* Prototypes for various functions defined later in this file. */
1.200 itojun 206: void destroy_sensitive_data(void);
1.231 provos 207: void demote_sensitive_data(void);
1.87 markus 208:
1.200 itojun 209: static void do_ssh1_kex(void);
210: static void do_ssh2_kex(void);
1.129 provos 211:
1.87 markus 212: /*
1.75 markus 213: * Close all listening sockets
214: */
1.200 itojun 215: static void
1.75 markus 216: close_listen_socks(void)
217: {
218: int i;
1.250 deraadt 219:
1.75 markus 220: for (i = 0; i < num_listen_socks; i++)
221: close(listen_socks[i]);
222: num_listen_socks = -1;
223: }
224:
1.211 markus 225: static void
226: close_startup_pipes(void)
227: {
228: int i;
1.250 deraadt 229:
1.211 markus 230: if (startup_pipes)
231: for (i = 0; i < options.max_startups; i++)
232: if (startup_pipes[i] != -1)
233: close(startup_pipes[i]);
234: }
235:
1.75 markus 236: /*
1.65 deraadt 237: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
238: * the effect is to reread the configuration file (and to regenerate
239: * the server key).
240: */
1.200 itojun 241: static void
1.64 markus 242: sighup_handler(int sig)
1.1 deraadt 243: {
1.210 deraadt 244: int save_errno = errno;
245:
1.64 markus 246: received_sighup = 1;
247: signal(SIGHUP, sighup_handler);
1.210 deraadt 248: errno = save_errno;
1.1 deraadt 249: }
250:
1.65 deraadt 251: /*
252: * Called from the main program after receiving SIGHUP.
253: * Restarts the server.
254: */
1.200 itojun 255: static void
1.165 itojun 256: sighup_restart(void)
1.1 deraadt 257: {
1.264 itojun 258: logit("Received SIGHUP; restarting.");
1.75 markus 259: close_listen_socks();
1.211 markus 260: close_startup_pipes();
1.64 markus 261: execv(saved_argv[0], saved_argv);
1.264 itojun 262: logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
1.250 deraadt 263: strerror(errno));
1.64 markus 264: exit(1);
1.1 deraadt 265: }
266:
1.65 deraadt 267: /*
268: * Generic signal handler for terminating signals in the master daemon.
269: */
1.200 itojun 270: static void
1.64 markus 271: sigterm_handler(int sig)
1.1 deraadt 272: {
1.199 markus 273: received_sigterm = sig;
1.1 deraadt 274: }
275:
1.65 deraadt 276: /*
277: * SIGCHLD handler. This is called whenever a child dies. This will then
1.199 markus 278: * reap any zombies left by exited children.
1.65 deraadt 279: */
1.200 itojun 280: static void
1.64 markus 281: main_sigchld_handler(int sig)
1.1 deraadt 282: {
1.250 deraadt 283: int save_errno = errno;
1.239 markus 284: pid_t pid;
1.64 markus 285: int status;
1.60 deraadt 286:
1.239 markus 287: while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
288: (pid < 0 && errno == EINTR))
1.64 markus 289: ;
1.60 deraadt 290:
1.64 markus 291: signal(SIGCHLD, main_sigchld_handler);
292: errno = save_errno;
1.1 deraadt 293: }
294:
1.65 deraadt 295: /*
296: * Signal handler for the alarm after the login grace period has expired.
297: */
1.200 itojun 298: static void
1.64 markus 299: grace_alarm_handler(int sig)
1.1 deraadt 300: {
1.199 markus 301: /* XXX no idea how fix this signal handler */
302:
1.285 dtucker 303: if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
304: kill(pmonitor->m_pid, SIGALRM);
305:
1.64 markus 306: /* Log error and exit. */
1.259 markus 307: fatal("Timeout before authentication for %s", get_remote_ipaddr());
1.62 markus 308: }
309:
1.65 deraadt 310: /*
311: * Signal handler for the key regeneration alarm. Note that this
312: * alarm only occurs in the daemon waiting for connections, and it does not
313: * do anything with the private key or random state before forking.
314: * Thus there should be no concurrency control/asynchronous execution
315: * problems.
316: */
1.200 itojun 317: static void
1.174 deraadt 318: generate_ephemeral_server_key(void)
1.134 markus 319: {
1.254 deraadt 320: u_int32_t rnd = 0;
1.169 markus 321: int i;
322:
1.191 markus 323: verbose("Generating %s%d bit RSA key.",
1.185 djm 324: sensitive_data.server_key ? "new " : "", options.server_key_bits);
1.134 markus 325: if (sensitive_data.server_key != NULL)
326: key_free(sensitive_data.server_key);
1.191 markus 327: sensitive_data.server_key = key_generate(KEY_RSA1,
1.185 djm 328: options.server_key_bits);
329: verbose("RSA key generation complete.");
1.169 markus 330:
331: for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
332: if (i % 4 == 0)
1.254 deraadt 333: rnd = arc4random();
334: sensitive_data.ssh1_cookie[i] = rnd & 0xff;
335: rnd >>= 8;
1.169 markus 336: }
1.134 markus 337: arc4random_stir();
338: }
1.147 deraadt 339:
1.200 itojun 340: static void
1.64 markus 341: key_regeneration_alarm(int sig)
1.1 deraadt 342: {
1.64 markus 343: int save_errno = errno;
1.250 deraadt 344:
1.151 markus 345: signal(SIGALRM, SIG_DFL);
1.64 markus 346: errno = save_errno;
1.151 markus 347: key_do_regen = 1;
1.98 markus 348: }
349:
1.200 itojun 350: static void
1.96 markus 351: sshd_exchange_identification(int sock_in, int sock_out)
352: {
1.102 markus 353: int i, mismatch;
1.96 markus 354: int remote_major, remote_minor;
1.102 markus 355: int major, minor;
1.96 markus 356: char *s;
357: char buf[256]; /* Must not be larger than remote_version. */
358: char remote_version[256]; /* Must be at least as big as buf. */
359:
1.103 markus 360: if ((options.protocol & SSH_PROTO_1) &&
361: (options.protocol & SSH_PROTO_2)) {
1.102 markus 362: major = PROTOCOL_MAJOR_1;
363: minor = 99;
364: } else if (options.protocol & SSH_PROTO_2) {
365: major = PROTOCOL_MAJOR_2;
366: minor = PROTOCOL_MINOR_2;
367: } else {
368: major = PROTOCOL_MAJOR_1;
369: minor = PROTOCOL_MINOR_1;
370: }
371: snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
1.96 markus 372: server_version_string = xstrdup(buf);
373:
1.272 markus 374: /* Send our protocol version identification. */
375: if (atomicio(vwrite, sock_out, server_version_string,
376: strlen(server_version_string))
377: != strlen(server_version_string)) {
378: logit("Could not write ident string to %s", get_remote_ipaddr());
1.278 markus 379: cleanup_exit(255);
1.272 markus 380: }
381:
382: /* Read other sides version identification. */
383: memset(buf, 0, sizeof(buf));
384: for (i = 0; i < sizeof(buf) - 1; i++) {
385: if (atomicio(read, sock_in, &buf[i], 1) != 1) {
386: logit("Did not receive identification string from %s",
387: get_remote_ipaddr());
1.278 markus 388: cleanup_exit(255);
1.96 markus 389: }
1.272 markus 390: if (buf[i] == '\r') {
391: buf[i] = 0;
392: /* Kludge for F-Secure Macintosh < 1.0.2 */
393: if (i == 12 &&
394: strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
1.96 markus 395: break;
1.272 markus 396: continue;
397: }
398: if (buf[i] == '\n') {
399: buf[i] = 0;
400: break;
1.96 markus 401: }
402: }
1.272 markus 403: buf[sizeof(buf) - 1] = 0;
404: client_version_string = xstrdup(buf);
1.96 markus 405:
406: /*
407: * Check that the versions match. In future this might accept
408: * several versions and set appropriate flags to handle them.
409: */
410: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
411: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 412: s = "Protocol mismatch.\n";
1.271 deraadt 413: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.96 markus 414: close(sock_in);
415: close(sock_out);
1.264 itojun 416: logit("Bad protocol version identification '%.100s' from %s",
1.96 markus 417: client_version_string, get_remote_ipaddr());
1.278 markus 418: cleanup_exit(255);
1.96 markus 419: }
420: debug("Client protocol version %d.%d; client software version %.100s",
1.217 deraadt 421: remote_major, remote_minor, remote_version);
1.96 markus 422:
1.98 markus 423: compat_datafellows(remote_version);
1.260 mickey 424:
425: if (datafellows & SSH_BUG_PROBE) {
1.264 itojun 426: logit("probed from %s with %s. Don't panic.",
1.260 mickey 427: get_remote_ipaddr(), client_version_string);
1.278 markus 428: cleanup_exit(255);
1.260 mickey 429: }
1.175 deraadt 430:
431: if (datafellows & SSH_BUG_SCANNER) {
1.264 itojun 432: logit("scanned from %s with %s. Don't panic.",
1.175 deraadt 433: get_remote_ipaddr(), client_version_string);
1.278 markus 434: cleanup_exit(255);
1.175 deraadt 435: }
1.98 markus 436:
1.102 markus 437: mismatch = 0;
1.214 deraadt 438: switch (remote_major) {
1.96 markus 439: case 1:
1.108 markus 440: if (remote_minor == 99) {
441: if (options.protocol & SSH_PROTO_2)
442: enable_compat20();
443: else
444: mismatch = 1;
445: break;
446: }
1.102 markus 447: if (!(options.protocol & SSH_PROTO_1)) {
448: mismatch = 1;
449: break;
450: }
1.96 markus 451: if (remote_minor < 3) {
1.121 provos 452: packet_disconnect("Your ssh version is too old and "
1.96 markus 453: "is no longer supported. Please install a newer version.");
454: } else if (remote_minor == 3) {
455: /* note that this disables agent-forwarding */
456: enable_compat13();
457: }
1.102 markus 458: break;
1.98 markus 459: case 2:
1.102 markus 460: if (options.protocol & SSH_PROTO_2) {
1.98 markus 461: enable_compat20();
462: break;
463: }
1.99 markus 464: /* FALLTHROUGH */
1.105 markus 465: default:
1.102 markus 466: mismatch = 1;
467: break;
468: }
469: chop(server_version_string);
470: debug("Local version string %.200s", server_version_string);
471:
472: if (mismatch) {
1.96 markus 473: s = "Protocol major versions differ.\n";
1.271 deraadt 474: (void) atomicio(vwrite, sock_out, s, strlen(s));
1.96 markus 475: close(sock_in);
476: close(sock_out);
1.264 itojun 477: logit("Protocol major versions differ for %s: %.200s vs. %.200s",
1.102 markus 478: get_remote_ipaddr(),
479: server_version_string, client_version_string);
1.278 markus 480: cleanup_exit(255);
1.96 markus 481: }
1.108 markus 482: }
483:
1.134 markus 484: /* Destroy the host and server keys. They will no longer be needed. */
1.108 markus 485: void
486: destroy_sensitive_data(void)
487: {
1.134 markus 488: int i;
489:
490: if (sensitive_data.server_key) {
491: key_free(sensitive_data.server_key);
492: sensitive_data.server_key = NULL;
493: }
1.217 deraadt 494: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 495: if (sensitive_data.host_keys[i]) {
496: key_free(sensitive_data.host_keys[i]);
497: sensitive_data.host_keys[i] = NULL;
498: }
499: }
500: sensitive_data.ssh1_host_key = NULL;
1.169 markus 501: memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
1.134 markus 502: }
503:
1.231 provos 504: /* Demote private to public keys for network child */
505: void
506: demote_sensitive_data(void)
507: {
508: Key *tmp;
509: int i;
510:
511: if (sensitive_data.server_key) {
512: tmp = key_demote(sensitive_data.server_key);
513: key_free(sensitive_data.server_key);
514: sensitive_data.server_key = tmp;
515: }
516:
517: for (i = 0; i < options.num_host_key_files; i++) {
518: if (sensitive_data.host_keys[i]) {
519: tmp = key_demote(sensitive_data.host_keys[i]);
520: key_free(sensitive_data.host_keys[i]);
521: sensitive_data.host_keys[i] = tmp;
522: if (tmp->type == KEY_RSA1)
523: sensitive_data.ssh1_host_key = tmp;
524: }
525: }
526:
527: /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
528: }
529:
1.233 markus 530: static void
1.231 provos 531: privsep_preauth_child(void)
532: {
1.254 deraadt 533: u_int32_t rnd[256];
1.253 deraadt 534: gid_t gidset[1];
1.250 deraadt 535: struct passwd *pw;
1.231 provos 536: int i;
537:
538: /* Enable challenge-response authentication for privilege separation */
539: privsep_challenge_enable();
540:
541: for (i = 0; i < 256; i++)
1.254 deraadt 542: rnd[i] = arc4random();
543: RAND_seed(rnd, sizeof(rnd));
1.231 provos 544:
545: /* Demote the private keys to public keys. */
546: demote_sensitive_data();
547:
1.235 stevesk 548: if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1.240 djm 549: fatal("Privilege separation user %s does not exist",
550: SSH_PRIVSEP_USER);
1.235 stevesk 551: memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
552: endpwent();
553:
1.255 deraadt 554: /* Change our root directory */
1.232 stevesk 555: if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
556: fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
557: strerror(errno));
1.231 provos 558: if (chdir("/") == -1)
1.236 stevesk 559: fatal("chdir(\"/\"): %s", strerror(errno));
1.234 markus 560:
1.231 provos 561: /* Drop our privileges */
1.235 stevesk 562: debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
563: (u_int)pw->pw_gid);
1.251 markus 564: #if 0
1.287 djm 565: /* XXX not ready, too heavy after chroot */
1.235 stevesk 566: do_setusercontext(pw);
1.251 markus 567: #else
568: gidset[0] = pw->pw_gid;
569: if (setgroups(1, gidset) < 0)
570: fatal("setgroups: %.100s", strerror(errno));
571: permanently_set_uid(pw);
572: #endif
1.231 provos 573: }
574:
1.278 markus 575: static int
576: privsep_preauth(Authctxt *authctxt)
1.237 markus 577: {
578: int status;
579: pid_t pid;
580:
581: /* Set up unprivileged child process to deal with network data */
1.242 mouring 582: pmonitor = monitor_init();
1.237 markus 583: /* Store a pointer to the kex for later rekeying */
1.242 mouring 584: pmonitor->m_pkex = &xxx_kex;
1.237 markus 585:
586: pid = fork();
587: if (pid == -1) {
588: fatal("fork of unprivileged child failed");
589: } else if (pid != 0) {
1.245 mpech 590: debug2("Network child is on pid %ld", (long)pid);
1.237 markus 591:
1.242 mouring 592: close(pmonitor->m_recvfd);
1.285 dtucker 593: pmonitor->m_pid = pid;
1.278 markus 594: monitor_child_preauth(authctxt, pmonitor);
1.242 mouring 595: close(pmonitor->m_sendfd);
1.237 markus 596:
597: /* Sync memory */
1.242 mouring 598: monitor_sync(pmonitor);
1.237 markus 599:
600: /* Wait for the child's exit status */
1.239 markus 601: while (waitpid(pid, &status, 0) < 0)
602: if (errno != EINTR)
603: break;
1.278 markus 604: return (1);
1.237 markus 605: } else {
606: /* child */
607:
1.242 mouring 608: close(pmonitor->m_sendfd);
1.237 markus 609:
610: /* Demote the child */
611: if (getuid() == 0 || geteuid() == 0)
612: privsep_preauth_child();
1.238 stevesk 613: setproctitle("%s", "[net]");
1.237 markus 614: }
1.278 markus 615: return (0);
1.237 markus 616: }
617:
1.233 markus 618: static void
1.237 markus 619: privsep_postauth(Authctxt *authctxt)
1.231 provos 620: {
621: if (authctxt->pw->pw_uid == 0 || options.use_login) {
622: /* File descriptor passing is broken or root login */
1.242 mouring 623: monitor_apply_keystate(pmonitor);
1.231 provos 624: use_privsep = 0;
625: return;
626: }
1.234 markus 627:
1.231 provos 628: /* Authentication complete */
629: alarm(0);
630: if (startup_pipe != -1) {
631: close(startup_pipe);
632: startup_pipe = -1;
633: }
634:
635: /* New socket pair */
1.242 mouring 636: monitor_reinit(pmonitor);
1.231 provos 637:
1.242 mouring 638: pmonitor->m_pid = fork();
639: if (pmonitor->m_pid == -1)
1.231 provos 640: fatal("fork of unprivileged child failed");
1.242 mouring 641: else if (pmonitor->m_pid != 0) {
1.245 mpech 642: debug2("User child is on pid %ld", (long)pmonitor->m_pid);
1.242 mouring 643: close(pmonitor->m_recvfd);
644: monitor_child_postauth(pmonitor);
1.231 provos 645:
646: /* NEVERREACHED */
647: exit(0);
648: }
649:
1.242 mouring 650: close(pmonitor->m_sendfd);
1.231 provos 651:
652: /* Demote the private keys to public keys. */
653: demote_sensitive_data();
654:
655: /* Drop privileges */
656: do_setusercontext(authctxt->pw);
657:
658: /* It is safe now to apply the key state */
1.242 mouring 659: monitor_apply_keystate(pmonitor);
1.231 provos 660: }
661:
1.200 itojun 662: static char *
1.134 markus 663: list_hostkey_types(void)
664: {
1.223 markus 665: Buffer b;
1.281 jakob 666: const char *p;
667: char *ret;
1.134 markus 668: int i;
1.223 markus 669:
670: buffer_init(&b);
1.217 deraadt 671: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 672: Key *key = sensitive_data.host_keys[i];
673: if (key == NULL)
674: continue;
1.214 deraadt 675: switch (key->type) {
1.134 markus 676: case KEY_RSA:
677: case KEY_DSA:
1.223 markus 678: if (buffer_len(&b) > 0)
679: buffer_append(&b, ",", 1);
680: p = key_ssh_name(key);
681: buffer_append(&b, p, strlen(p));
1.134 markus 682: break;
683: }
684: }
1.223 markus 685: buffer_append(&b, "\0", 1);
1.281 jakob 686: ret = xstrdup(buffer_ptr(&b));
1.223 markus 687: buffer_free(&b);
1.281 jakob 688: debug("list_hostkey_types: %s", ret);
689: return ret;
1.134 markus 690: }
691:
1.231 provos 692: Key *
1.134 markus 693: get_hostkey_by_type(int type)
694: {
695: int i;
1.250 deraadt 696:
1.217 deraadt 697: for (i = 0; i < options.num_host_key_files; i++) {
1.134 markus 698: Key *key = sensitive_data.host_keys[i];
699: if (key != NULL && key->type == type)
700: return key;
701: }
702: return NULL;
1.96 markus 703: }
704:
1.231 provos 705: Key *
706: get_hostkey_by_index(int ind)
707: {
708: if (ind < 0 || ind >= options.num_host_key_files)
709: return (NULL);
710: return (sensitive_data.host_keys[ind]);
711: }
712:
713: int
714: get_hostkey_index(Key *key)
715: {
716: int i;
1.250 deraadt 717:
1.231 provos 718: for (i = 0; i < options.num_host_key_files; i++) {
719: if (key == sensitive_data.host_keys[i])
720: return (i);
721: }
722: return (-1);
723: }
724:
1.124 markus 725: /*
726: * returns 1 if connection should be dropped, 0 otherwise.
727: * dropping starts at connection #max_startups_begin with a probability
728: * of (max_startups_rate/100). the probability increases linearly until
729: * all connections are dropped for startups > max_startups
730: */
1.200 itojun 731: static int
1.124 markus 732: drop_connection(int startups)
733: {
734: double p, r;
735:
736: if (startups < options.max_startups_begin)
737: return 0;
738: if (startups >= options.max_startups)
739: return 1;
740: if (options.max_startups_rate == 100)
741: return 1;
742:
743: p = 100 - options.max_startups_rate;
744: p *= startups - options.max_startups_begin;
745: p /= (double) (options.max_startups - options.max_startups_begin);
746: p += options.max_startups_rate;
747: p /= 100.0;
748: r = arc4random() / (double) UINT_MAX;
749:
750: debug("drop_connection: p %g, r %g", p, r);
751: return (r < p) ? 1 : 0;
752: }
753:
1.215 markus 754: static void
755: usage(void)
756: {
1.290 markus 757: fprintf(stderr, "%s, %s\n",
1.280 markus 758: SSH_VERSION, SSLeay_version(SSLEAY_VERSION));
1.289 markus 759: fprintf(stderr,
760: "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n"
761: " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n"
762: );
1.215 markus 763: exit(1);
764: }
765:
1.294 ! djm 766: static void
! 767: send_rexec_state(int fd, Buffer *conf)
! 768: {
! 769: Buffer m;
! 770:
! 771: debug3("%s: entering fd = %d config len %d", __func__, fd,
! 772: buffer_len(conf));
! 773:
! 774: /*
! 775: * Protocol from reexec master to child:
! 776: * string configuration
! 777: * u_int ephemeral_key_follows
! 778: * bignum e (only if ephemeral_key_follows == 1)
! 779: * bignum n "
! 780: * bignum d "
! 781: * bignum iqmp "
! 782: * bignum p "
! 783: * bignum q "
! 784: */
! 785: buffer_init(&m);
! 786: buffer_put_cstring(&m, buffer_ptr(conf));
! 787:
! 788: if (sensitive_data.server_key != NULL &&
! 789: sensitive_data.server_key->type == KEY_RSA1) {
! 790: buffer_put_int(&m, 1);
! 791: buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
! 792: buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
! 793: buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
! 794: buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
! 795: buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
! 796: buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
! 797: } else
! 798: buffer_put_int(&m, 0);
! 799:
! 800: if (ssh_msg_send(fd, 0, &m) == -1)
! 801: fatal("%s: ssh_msg_send failed", __func__);
! 802:
! 803: buffer_free(&m);
! 804:
! 805: debug3("%s: done", __func__);
! 806: }
! 807:
! 808: static void
! 809: recv_rexec_state(int fd, Buffer *conf)
! 810: {
! 811: Buffer m;
! 812: char *cp;
! 813: u_int len;
! 814:
! 815: debug3("%s: entering fd = %d", __func__, fd);
! 816:
! 817: buffer_init(&m);
! 818:
! 819: if (ssh_msg_recv(fd, &m) == -1)
! 820: fatal("%s: ssh_msg_recv failed", __func__);
! 821: if (buffer_get_char(&m) != 0)
! 822: fatal("%s: rexec version mismatch", __func__);
! 823:
! 824: cp = buffer_get_string(&m, &len);
! 825: if (conf != NULL)
! 826: buffer_append(conf, cp, len + 1);
! 827: xfree(cp);
! 828:
! 829: if (buffer_get_int(&m)) {
! 830: if (sensitive_data.server_key != NULL)
! 831: key_free(sensitive_data.server_key);
! 832: sensitive_data.server_key = key_new_private(KEY_RSA1);
! 833: buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
! 834: buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
! 835: buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
! 836: buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
! 837: buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
! 838: buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
! 839: rsa_generate_additional_parameters(
! 840: sensitive_data.server_key->rsa);
! 841: }
! 842: buffer_free(&m);
! 843:
! 844: debug3("%s: done", __func__);
! 845: }
! 846:
1.65 deraadt 847: /*
848: * Main program for the daemon.
849: */
1.2 provos 850: int
851: main(int ac, char **av)
1.1 deraadt 852: {
1.64 markus 853: extern char *optarg;
854: extern int optind;
1.120 markus 855: int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
1.107 deraadt 856: pid_t pid;
1.75 markus 857: socklen_t fromlen;
858: fd_set *fdset;
859: struct sockaddr_storage from;
1.64 markus 860: const char *remote_ip;
861: int remote_port;
862: FILE *f;
1.75 markus 863: struct addrinfo *ai;
864: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.283 markus 865: char *line;
1.75 markus 866: int listen_sock, maxfd;
1.294 ! djm 867: int startup_p[2], config_s[2];
1.120 markus 868: int startups = 0;
1.278 markus 869: Key *key;
1.230 provos 870: Authctxt *authctxt;
1.151 markus 871: int ret, key_used = 0;
1.294 ! djm 872: Buffer cfg;
1.64 markus 873:
1.138 markus 874: /* Save argv. */
1.64 markus 875: saved_argv = av;
1.294 ! djm 876: rexec_argc = ac;
1.64 markus 877:
878: /* Initialize configuration options to their default values. */
879: initialize_server_options(&options);
880:
881: /* Parse command-line arguments. */
1.294 ! djm 882: while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) {
1.64 markus 883: switch (opt) {
1.75 markus 884: case '4':
885: IPv4or6 = AF_INET;
886: break;
887: case '6':
888: IPv4or6 = AF_INET6;
889: break;
1.64 markus 890: case 'f':
891: config_file_name = optarg;
892: break;
893: case 'd':
1.273 markus 894: if (debug_flag == 0) {
1.127 markus 895: debug_flag = 1;
896: options.log_level = SYSLOG_LEVEL_DEBUG1;
1.273 markus 897: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1.127 markus 898: options.log_level++;
1.64 markus 899: break;
1.135 markus 900: case 'D':
901: no_daemon_flag = 1;
1.192 lebel 902: break;
903: case 'e':
904: log_stderr = 1;
1.135 markus 905: break;
1.64 markus 906: case 'i':
907: inetd_flag = 1;
908: break;
1.294 ! djm 909: case 'r':
! 910: rexec_flag = 0;
! 911: break;
! 912: case 'R':
! 913: rexeced_flag = 1;
! 914: inetd_flag = 1;
! 915: break;
1.64 markus 916: case 'Q':
1.158 markus 917: /* ignored */
1.64 markus 918: break;
919: case 'q':
920: options.log_level = SYSLOG_LEVEL_QUIET;
921: break;
922: case 'b':
923: options.server_key_bits = atoi(optarg);
924: break;
925: case 'p':
1.75 markus 926: options.ports_from_cmdline = 1;
1.127 markus 927: if (options.num_ports >= MAX_PORTS) {
928: fprintf(stderr, "too many ports.\n");
929: exit(1);
930: }
1.193 stevesk 931: options.ports[options.num_ports++] = a2port(optarg);
932: if (options.ports[options.num_ports-1] == 0) {
933: fprintf(stderr, "Bad port number.\n");
934: exit(1);
935: }
1.64 markus 936: break;
937: case 'g':
1.197 stevesk 938: if ((options.login_grace_time = convtime(optarg)) == -1) {
939: fprintf(stderr, "Invalid login grace time.\n");
940: exit(1);
941: }
1.64 markus 942: break;
943: case 'k':
1.197 stevesk 944: if ((options.key_regeneration_time = convtime(optarg)) == -1) {
945: fprintf(stderr, "Invalid key regeneration interval.\n");
946: exit(1);
947: }
1.64 markus 948: break;
949: case 'h':
1.134 markus 950: if (options.num_host_key_files >= MAX_HOSTKEYS) {
951: fprintf(stderr, "too many host keys.\n");
952: exit(1);
953: }
954: options.host_key_files[options.num_host_key_files++] = optarg;
1.64 markus 955: break;
1.203 stevesk 956: case 't':
957: test_flag = 1;
958: break;
1.125 markus 959: case 'u':
960: utmp_len = atoi(optarg);
1.257 stevesk 961: if (utmp_len > MAXHOSTNAMELEN) {
962: fprintf(stderr, "Invalid utmp length.\n");
963: exit(1);
964: }
1.125 markus 965: break;
1.215 markus 966: case 'o':
1.283 markus 967: line = xstrdup(optarg);
968: if (process_server_config_line(&options, line,
1.215 markus 969: "command-line", 0) != 0)
1.217 deraadt 970: exit(1);
1.283 markus 971: xfree(line);
1.215 markus 972: break;
1.64 markus 973: case '?':
974: default:
1.215 markus 975: usage();
976: break;
1.64 markus 977: }
978: }
1.294 ! djm 979: if (rexeced_flag || inetd_flag)
! 980: rexec_flag = 0;
! 981: if (rexec_flag && (av[0] == NULL || *av[0] != '/'))
! 982: fatal("sshd re-exec requires execution with an absolute path");
! 983: if (rexeced_flag)
! 984: closefrom(STDERR_FILENO + 3);
! 985:
1.180 markus 986: SSLeay_add_all_algorithms();
1.205 markus 987: channel_set_af(IPv4or6);
1.64 markus 988:
1.75 markus 989: /*
990: * Force logging to stderr until we have loaded the private host
991: * key (unless started from inetd)
992: */
1.138 markus 993: log_init(__progname,
1.224 markus 994: options.log_level == SYSLOG_LEVEL_NOT_SET ?
995: SYSLOG_LEVEL_INFO : options.log_level,
996: options.log_facility == SYSLOG_FACILITY_NOT_SET ?
997: SYSLOG_FACILITY_AUTH : options.log_facility,
1.261 markus 998: log_stderr || !inetd_flag);
1.75 markus 999:
1.294 ! djm 1000: sensitive_data.server_key = NULL;
! 1001: sensitive_data.ssh1_host_key = NULL;
! 1002: sensitive_data.have_ssh1_key = 0;
! 1003: sensitive_data.have_ssh2_key = 0;
! 1004:
! 1005: /* Fetch our configuration */
! 1006: buffer_init(&cfg);
! 1007: if (rexeced_flag)
! 1008: recv_rexec_state(STDERR_FILENO + 2, &cfg);
! 1009: else
! 1010: load_server_config(config_file_name, &cfg);
! 1011:
! 1012: parse_server_config(&options,
! 1013: rexeced_flag ? "rexec" : config_file_name, &cfg);
! 1014:
! 1015: if (!rexec_flag)
! 1016: buffer_free(&cfg);
1.64 markus 1017:
1018: /* Fill in default values for those options not explicitly set. */
1019: fill_default_server_options(&options);
1020:
1021: /* Check that there are no remaining arguments. */
1022: if (optind < ac) {
1023: fprintf(stderr, "Extra argument %s.\n", av[optind]);
1024: exit(1);
1025: }
1026:
1027: debug("sshd version %.100s", SSH_VERSION);
1028:
1.134 markus 1029: /* load private host keys */
1.255 deraadt 1030: sensitive_data.host_keys = xmalloc(options.num_host_key_files *
1031: sizeof(Key *));
1.217 deraadt 1032: for (i = 0; i < options.num_host_key_files; i++)
1.141 markus 1033: sensitive_data.host_keys[i] = NULL;
1.134 markus 1034:
1.217 deraadt 1035: for (i = 0; i < options.num_host_key_files; i++) {
1.179 markus 1036: key = key_load_private(options.host_key_files[i], "", NULL);
1037: sensitive_data.host_keys[i] = key;
1.134 markus 1038: if (key == NULL) {
1.195 markus 1039: error("Could not load host key: %s",
1040: options.host_key_files[i]);
1.179 markus 1041: sensitive_data.host_keys[i] = NULL;
1.134 markus 1042: continue;
1043: }
1.214 deraadt 1044: switch (key->type) {
1.134 markus 1045: case KEY_RSA1:
1046: sensitive_data.ssh1_host_key = key;
1047: sensitive_data.have_ssh1_key = 1;
1048: break;
1049: case KEY_RSA:
1050: case KEY_DSA:
1051: sensitive_data.have_ssh2_key = 1;
1052: break;
1053: }
1.179 markus 1054: debug("private host key: #%d type %d %s", i, key->type,
1055: key_type(key));
1.134 markus 1056: }
1057: if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1.264 itojun 1058: logit("Disabling protocol version 1. Could not load host key");
1.108 markus 1059: options.protocol &= ~SSH_PROTO_1;
1060: }
1.134 markus 1061: if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1.264 itojun 1062: logit("Disabling protocol version 2. Could not load host key");
1.134 markus 1063: options.protocol &= ~SSH_PROTO_2;
1.108 markus 1064: }
1.162 stevesk 1065: if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1.264 itojun 1066: logit("sshd: no hostkeys available -- exiting.");
1.64 markus 1067: exit(1);
1068: }
1069:
1.108 markus 1070: /* Check certain values for sanity. */
1071: if (options.protocol & SSH_PROTO_1) {
1072: if (options.server_key_bits < 512 ||
1073: options.server_key_bits > 32768) {
1074: fprintf(stderr, "Bad server key size.\n");
1075: exit(1);
1076: }
1077: /*
1078: * Check that server and host key lengths differ sufficiently. This
1079: * is necessary to make double encryption work with rsaref. Oh, I
1080: * hate software patents. I dont know if this can go? Niels
1081: */
1082: if (options.server_key_bits >
1.250 deraadt 1083: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1084: SSH_KEY_BITS_RESERVED && options.server_key_bits <
1085: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1086: SSH_KEY_BITS_RESERVED) {
1.108 markus 1087: options.server_key_bits =
1.250 deraadt 1088: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1089: SSH_KEY_BITS_RESERVED;
1.108 markus 1090: debug("Forcing server key to %d bits to make it differ from host key.",
1091: options.server_key_bits);
1092: }
1.244 markus 1093: }
1094:
1095: if (use_privsep) {
1096: struct passwd *pw;
1097: struct stat st;
1098:
1099: if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1100: fatal("Privilege separation user %s does not exist",
1101: SSH_PRIVSEP_USER);
1102: if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1103: (S_ISDIR(st.st_mode) == 0))
1104: fatal("Missing privilege separation directory: %s",
1.247 stevesk 1105: _PATH_PRIVSEP_CHROOT_DIR);
1106: if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1.262 markus 1107: fatal("%s must be owned by root and not group or "
1108: "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1.108 markus 1109: }
1.203 stevesk 1110:
1111: /* Configuration looks good, so exit if in test mode. */
1112: if (test_flag)
1113: exit(0);
1.108 markus 1114:
1.294 ! djm 1115: if (rexec_flag) {
! 1116: rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2));
! 1117: for (i = 0; i < rexec_argc; i++) {
! 1118: debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
! 1119: rexec_argv[i] = saved_argv[i];
! 1120: }
! 1121: rexec_argv[rexec_argc] = "-R";
! 1122: rexec_argv[rexec_argc + 1] = NULL;
! 1123: }
! 1124:
1.108 markus 1125: /* Initialize the log (it is reinitialized below in case we forked). */
1.64 markus 1126: if (debug_flag && !inetd_flag)
1127: log_stderr = 1;
1.138 markus 1128: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1129:
1.108 markus 1130: /*
1131: * If not in debugging mode, and not started from inetd, disconnect
1132: * from the controlling terminal, and fork. The original process
1133: * exits.
1134: */
1.135 markus 1135: if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1.1 deraadt 1136: #ifdef TIOCNOTTY
1.64 markus 1137: int fd;
1.1 deraadt 1138: #endif /* TIOCNOTTY */
1.64 markus 1139: if (daemon(0, 0) < 0)
1140: fatal("daemon() failed: %.200s", strerror(errno));
1141:
1142: /* Disconnect from the controlling tty. */
1.1 deraadt 1143: #ifdef TIOCNOTTY
1.165 itojun 1144: fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1.64 markus 1145: if (fd >= 0) {
1146: (void) ioctl(fd, TIOCNOTTY, NULL);
1147: close(fd);
1148: }
1149: #endif /* TIOCNOTTY */
1150: }
1151: /* Reinitialize the log (because of the fork above). */
1.138 markus 1152: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 1153:
1154: /* Initialize the random number generator. */
1155: arc4random_stir();
1156:
1157: /* Chdir to the root directory so that the current disk can be
1158: unmounted if desired. */
1159: chdir("/");
1.217 deraadt 1160:
1.178 markus 1161: /* ignore SIGPIPE */
1162: signal(SIGPIPE, SIG_IGN);
1.64 markus 1163:
1164: /* Start listening for a socket, unless started from inetd. */
1165: if (inetd_flag) {
1.294 ! djm 1166: int fd;
! 1167:
1.123 djm 1168: startup_pipe = -1;
1.294 ! djm 1169: if (rexeced_flag) {
! 1170: close(STDERR_FILENO + 2);
! 1171: sock_in = sock_out = dup(STDIN_FILENO);
! 1172: if (!debug_flag) {
! 1173: startup_pipe = dup(STDERR_FILENO + 1);
! 1174: close(STDERR_FILENO + 1);
! 1175: }
! 1176: } else {
! 1177: sock_in = dup(STDIN_FILENO);
! 1178: sock_out = dup(STDOUT_FILENO);
! 1179: }
1.108 markus 1180: /*
1181: * We intentionally do not close the descriptors 0, 1, and 2
1.294 ! djm 1182: * as our code for setting the descriptors won't work if
1.108 markus 1183: * ttyfd happens to be one of those.
1184: */
1.294 ! djm 1185: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
! 1186: dup2(fd, STDIN_FILENO);
! 1187: dup2(fd, STDOUT_FILENO);
! 1188: if (fd > STDOUT_FILENO)
! 1189: close(fd);
! 1190: }
1.64 markus 1191: debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1.294 ! djm 1192: if ((options.protocol & SSH_PROTO_1) &&
! 1193: sensitive_data.server_key == NULL)
1.174 deraadt 1194: generate_ephemeral_server_key();
1.64 markus 1195: } else {
1.75 markus 1196: for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1197: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1198: continue;
1199: if (num_listen_socks >= MAX_LISTEN_SOCKS)
1200: fatal("Too many listen sockets. "
1201: "Enlarge MAX_LISTEN_SOCKS");
1202: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1203: ntop, sizeof(ntop), strport, sizeof(strport),
1204: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1205: error("getnameinfo failed");
1206: continue;
1207: }
1208: /* Create socket for listening. */
1.265 markus 1209: listen_sock = socket(ai->ai_family, ai->ai_socktype,
1210: ai->ai_protocol);
1.75 markus 1211: if (listen_sock < 0) {
1212: /* kernel may not support ipv6 */
1213: verbose("socket: %.100s", strerror(errno));
1214: continue;
1215: }
1.293 djm 1216: if (set_nonblock(listen_sock) == -1) {
1.286 markus 1217: close(listen_sock);
1218: continue;
1219: }
1.75 markus 1220: /*
1.258 stevesk 1221: * Set socket options.
1222: * Allow local port reuse in TIME_WAIT.
1.75 markus 1223: */
1.258 stevesk 1224: if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1225: &on, sizeof(on)) == -1)
1226: error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1.75 markus 1227:
1228: debug("Bind to port %s on %s.", strport, ntop);
1229:
1230: /* Bind the socket to the desired port. */
1231: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1232: error("Bind to port %s on %s failed: %.200s.",
1233: strport, ntop, strerror(errno));
1234: close(listen_sock);
1235: continue;
1236: }
1237: listen_socks[num_listen_socks] = listen_sock;
1238: num_listen_socks++;
1239:
1240: /* Start listening on the port. */
1.264 itojun 1241: logit("Server listening on %s port %s.", ntop, strport);
1.282 markus 1242: if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1.75 markus 1243: fatal("listen: %.100s", strerror(errno));
1244:
1.64 markus 1245: }
1.75 markus 1246: freeaddrinfo(options.listen_addrs);
1247:
1248: if (!num_listen_socks)
1249: fatal("Cannot bind any address.");
1250:
1.201 markus 1251: if (options.protocol & SSH_PROTO_1)
1252: generate_ephemeral_server_key();
1253:
1254: /*
1255: * Arrange to restart on SIGHUP. The handler needs
1256: * listen_sock.
1257: */
1258: signal(SIGHUP, sighup_handler);
1259:
1260: signal(SIGTERM, sigterm_handler);
1261: signal(SIGQUIT, sigterm_handler);
1262:
1263: /* Arrange SIGCHLD to be caught. */
1264: signal(SIGCHLD, main_sigchld_handler);
1265:
1266: /* Write out the pid file after the sigterm handler is setup */
1.64 markus 1267: if (!debug_flag) {
1.66 markus 1268: /*
1.136 todd 1269: * Record our pid in /var/run/sshd.pid to make it
1270: * easier to kill the correct sshd. We don't want to
1271: * do this before the bind above because the bind will
1.66 markus 1272: * fail if there already is a daemon, and this will
1273: * overwrite any old pid in the file.
1274: */
1.112 markus 1275: f = fopen(options.pid_file, "w");
1.270 djm 1276: if (f == NULL) {
1277: error("Couldn't create pid file \"%s\": %s",
1278: options.pid_file, strerror(errno));
1279: } else {
1.245 mpech 1280: fprintf(f, "%ld\n", (long) getpid());
1.64 markus 1281: fclose(f);
1282: }
1283: }
1284:
1.75 markus 1285: /* setup fd set for listen */
1.120 markus 1286: fdset = NULL;
1.75 markus 1287: maxfd = 0;
1288: for (i = 0; i < num_listen_socks; i++)
1289: if (listen_socks[i] > maxfd)
1290: maxfd = listen_socks[i];
1.120 markus 1291: /* pipes connected to unauthenticated childs */
1292: startup_pipes = xmalloc(options.max_startups * sizeof(int));
1293: for (i = 0; i < options.max_startups; i++)
1294: startup_pipes[i] = -1;
1.75 markus 1295:
1.66 markus 1296: /*
1297: * Stay listening for connections until the system crashes or
1298: * the daemon is killed with a signal.
1299: */
1.64 markus 1300: for (;;) {
1301: if (received_sighup)
1302: sighup_restart();
1.120 markus 1303: if (fdset != NULL)
1304: xfree(fdset);
1.148 markus 1305: fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1.120 markus 1306: fdset = (fd_set *)xmalloc(fdsetsz);
1.75 markus 1307: memset(fdset, 0, fdsetsz);
1.120 markus 1308:
1.75 markus 1309: for (i = 0; i < num_listen_socks; i++)
1310: FD_SET(listen_socks[i], fdset);
1.120 markus 1311: for (i = 0; i < options.max_startups; i++)
1312: if (startup_pipes[i] != -1)
1313: FD_SET(startup_pipes[i], fdset);
1314:
1315: /* Wait in select until there is a connection. */
1.151 markus 1316: ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1317: if (ret < 0 && errno != EINTR)
1318: error("select: %.100s", strerror(errno));
1.199 markus 1319: if (received_sigterm) {
1.264 itojun 1320: logit("Received signal %d; terminating.",
1.213 itojun 1321: (int) received_sigterm);
1.199 markus 1322: close_listen_socks();
1323: unlink(options.pid_file);
1324: exit(255);
1325: }
1.151 markus 1326: if (key_used && key_do_regen) {
1.174 deraadt 1327: generate_ephemeral_server_key();
1.151 markus 1328: key_used = 0;
1329: key_do_regen = 0;
1330: }
1331: if (ret < 0)
1.75 markus 1332: continue;
1.151 markus 1333:
1.120 markus 1334: for (i = 0; i < options.max_startups; i++)
1335: if (startup_pipes[i] != -1 &&
1336: FD_ISSET(startup_pipes[i], fdset)) {
1337: /*
1338: * the read end of the pipe is ready
1339: * if the child has closed the pipe
1.143 markus 1340: * after successful authentication
1.120 markus 1341: * or if the child has died
1342: */
1343: close(startup_pipes[i]);
1344: startup_pipes[i] = -1;
1345: startups--;
1346: }
1.75 markus 1347: for (i = 0; i < num_listen_socks; i++) {
1348: if (!FD_ISSET(listen_socks[i], fdset))
1.70 provos 1349: continue;
1.120 markus 1350: fromlen = sizeof(from);
1351: newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1352: &fromlen);
1353: if (newsock < 0) {
1354: if (errno != EINTR && errno != EWOULDBLOCK)
1355: error("accept: %.100s", strerror(errno));
1.286 markus 1356: continue;
1357: }
1.293 djm 1358: if (unset_nonblock(newsock) == -1) {
1.286 markus 1359: close(newsock);
1.120 markus 1360: continue;
1361: }
1.124 markus 1362: if (drop_connection(startups) == 1) {
1363: debug("drop connection #%d", startups);
1.120 markus 1364: close(newsock);
1365: continue;
1366: }
1367: if (pipe(startup_p) == -1) {
1368: close(newsock);
1369: continue;
1370: }
1371:
1.294 ! djm 1372: if (rexec_flag && socketpair(AF_UNIX,
! 1373: SOCK_STREAM, 0, config_s) == -1) {
! 1374: error("reexec socketpair: %s",
! 1375: strerror(errno));
! 1376: close(newsock);
! 1377: close(startup_p[0]);
! 1378: close(startup_p[1]);
! 1379: continue;
! 1380: }
! 1381:
1.120 markus 1382: for (j = 0; j < options.max_startups; j++)
1383: if (startup_pipes[j] == -1) {
1384: startup_pipes[j] = startup_p[0];
1385: if (maxfd < startup_p[0])
1386: maxfd = startup_p[0];
1387: startups++;
1388: break;
1389: }
1.161 stevesk 1390:
1.66 markus 1391: /*
1.120 markus 1392: * Got connection. Fork a child to handle it, unless
1393: * we are in debugging mode.
1.66 markus 1394: */
1.120 markus 1395: if (debug_flag) {
1.66 markus 1396: /*
1.120 markus 1397: * In debugging mode. Close the listening
1398: * socket, and start processing the
1399: * connection without forking.
1.66 markus 1400: */
1.120 markus 1401: debug("Server will not fork when running in debugging mode.");
1.75 markus 1402: close_listen_socks();
1.64 markus 1403: sock_in = newsock;
1404: sock_out = newsock;
1.294 ! djm 1405: close(startup_p[0]);
! 1406: close(startup_p[1]);
1.122 deraadt 1407: startup_pipe = -1;
1.120 markus 1408: pid = getpid();
1.294 ! djm 1409: if (rexec_flag) {
! 1410: send_rexec_state(config_s[0],
! 1411: &cfg);
! 1412: close(config_s[0]);
! 1413: }
1.64 markus 1414: break;
1.120 markus 1415: } else {
1416: /*
1417: * Normal production daemon. Fork, and have
1418: * the child process the connection. The
1419: * parent continues listening.
1420: */
1421: if ((pid = fork()) == 0) {
1422: /*
1423: * Child. Close the listening and max_startup
1424: * sockets. Start using the accepted socket.
1425: * Reinitialize logging (since our pid has
1426: * changed). We break out of the loop to handle
1427: * the connection.
1428: */
1429: startup_pipe = startup_p[1];
1.211 markus 1430: close_startup_pipes();
1.120 markus 1431: close_listen_socks();
1432: sock_in = newsock;
1433: sock_out = newsock;
1.138 markus 1434: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.120 markus 1435: break;
1436: }
1.64 markus 1437: }
1438:
1.120 markus 1439: /* Parent. Stay in the loop. */
1440: if (pid < 0)
1441: error("fork: %.100s", strerror(errno));
1442: else
1.245 mpech 1443: debug("Forked child %ld.", (long)pid);
1.120 markus 1444:
1445: close(startup_p[1]);
1.1 deraadt 1446:
1.294 ! djm 1447: if (rexec_flag) {
! 1448: send_rexec_state(config_s[0], &cfg);
! 1449: close(config_s[0]);
! 1450: close(config_s[1]);
! 1451: }
! 1452:
1.120 markus 1453: /* Mark that the key has been used (it was "given" to the child). */
1.151 markus 1454: if ((options.protocol & SSH_PROTO_1) &&
1455: key_used == 0) {
1456: /* Schedule server key regeneration alarm. */
1457: signal(SIGALRM, key_regeneration_alarm);
1458: alarm(options.key_regeneration_time);
1459: key_used = 1;
1460: }
1.1 deraadt 1461:
1.120 markus 1462: arc4random_stir();
1.1 deraadt 1463:
1.120 markus 1464: /* Close the new socket (the child is now taking care of it). */
1465: close(newsock);
1466: }
1.75 markus 1467: /* child process check (or debug mode) */
1468: if (num_listen_socks < 0)
1469: break;
1.64 markus 1470: }
1.1 deraadt 1471: }
1472:
1.64 markus 1473: /* This is the child processing a new connection. */
1.288 markus 1474: setproctitle("%s", "[accepted]");
1.294 ! djm 1475:
! 1476: if (rexec_flag) {
! 1477: int fd;
! 1478:
! 1479: debug("rexec newsock %d pipe %d sock %d", newsock,
! 1480: startup_pipe, config_s[0]);
! 1481: dup2(newsock, STDIN_FILENO);
! 1482: dup2(STDIN_FILENO, STDOUT_FILENO);
! 1483: if (startup_pipe == -1)
! 1484: close(STDERR_FILENO + 1);
! 1485: else
! 1486: dup2(startup_pipe, STDERR_FILENO + 1);
! 1487:
! 1488: dup2(config_s[1], STDERR_FILENO + 2);
! 1489: close(config_s[1]);
! 1490: execv(rexec_argv[0], rexec_argv);
! 1491:
! 1492: /* Reexec has failed, fall back and continue */
! 1493: error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
! 1494: recv_rexec_state(STDERR_FILENO + 2, NULL);
! 1495: log_init(__progname, options.log_level,
! 1496: options.log_facility, log_stderr);
! 1497:
! 1498: /* Clean up fds */
! 1499: close(config_s[1]);
! 1500: close(STDERR_FILENO + 1);
! 1501: close(STDERR_FILENO + 2);
! 1502: if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
! 1503: dup2(fd, STDIN_FILENO);
! 1504: dup2(fd, STDOUT_FILENO);
! 1505: if (fd > STDERR_FILENO)
! 1506: close(fd);
! 1507: }
! 1508: }
1.241 millert 1509:
1510: /*
1511: * Create a new session and process group since the 4.4BSD
1512: * setlogin() affects the entire process group. We don't
1513: * want the child to be able to affect the parent.
1514: */
1.248 stevesk 1515: if (!debug_flag && !inetd_flag && setsid() < 0)
1.241 millert 1516: error("setsid: %.100s", strerror(errno));
1.64 markus 1517:
1.66 markus 1518: /*
1519: * Disable the key regeneration alarm. We will not regenerate the
1520: * key since we are no longer in a position to give it to anyone. We
1521: * will not restart on SIGHUP since it no longer makes sense.
1522: */
1.64 markus 1523: alarm(0);
1524: signal(SIGALRM, SIG_DFL);
1525: signal(SIGHUP, SIG_DFL);
1526: signal(SIGTERM, SIG_DFL);
1527: signal(SIGQUIT, SIG_DFL);
1528: signal(SIGCHLD, SIG_DFL);
1.150 markus 1529:
1.284 markus 1530: /* Set SO_KEEPALIVE if requested. */
1531: if (options.tcp_keep_alive &&
1.228 stevesk 1532: setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1.150 markus 1533: sizeof(on)) < 0)
1534: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1.64 markus 1535:
1.66 markus 1536: /*
1537: * Register our connection. This turns encryption off because we do
1538: * not have a key.
1539: */
1.64 markus 1540: packet_set_connection(sock_in, sock_out);
1.1 deraadt 1541:
1.64 markus 1542: remote_port = get_remote_port();
1543: remote_ip = get_remote_ipaddr();
1.52 markus 1544:
1.209 markus 1545: #ifdef LIBWRAP
1.64 markus 1546: /* Check whether logins are denied from this host. */
1547: {
1548: struct request_info req;
1.37 dugsong 1549:
1.204 camield 1550: request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1.64 markus 1551: fromhost(&req);
1.37 dugsong 1552:
1.64 markus 1553: if (!hosts_access(&req)) {
1.209 markus 1554: debug("Connection refused by tcp wrapper");
1.182 markus 1555: refuse(&req);
1.209 markus 1556: /* NOTREACHED */
1557: fatal("libwrap refuse returns");
1.64 markus 1558: }
1559: }
1.75 markus 1560: #endif /* LIBWRAP */
1.209 markus 1561:
1.64 markus 1562: /* Log the connection. */
1563: verbose("Connection from %.500s port %d", remote_ip, remote_port);
1.1 deraadt 1564:
1.66 markus 1565: /*
1566: * We don\'t want to listen forever unless the other side
1567: * successfully authenticates itself. So we set up an alarm which is
1568: * cleared after successful authentication. A limit of zero
1569: * indicates no limit. Note that we don\'t set the alarm in debugging
1570: * mode; it is just annoying to have the server exit just when you
1571: * are about to discover the bug.
1572: */
1.64 markus 1573: signal(SIGALRM, grace_alarm_handler);
1574: if (!debug_flag)
1575: alarm(options.login_grace_time);
1576:
1.96 markus 1577: sshd_exchange_identification(sock_in, sock_out);
1.275 markus 1578:
1.64 markus 1579: packet_set_nonblocking();
1.1 deraadt 1580:
1.278 markus 1581: /* allocate authentication context */
1582: authctxt = xmalloc(sizeof(*authctxt));
1583: memset(authctxt, 0, sizeof(*authctxt));
1584:
1585: /* XXX global for cleanup, access from other modules */
1586: the_authctxt = authctxt;
1587:
1.237 markus 1588: if (use_privsep)
1.278 markus 1589: if (privsep_preauth(authctxt) == 1)
1.237 markus 1590: goto authenticated;
1.231 provos 1591:
1.77 markus 1592: /* perform the key exchange */
1593: /* authenticate user and start session */
1.98 markus 1594: if (compat20) {
1595: do_ssh2_kex();
1.278 markus 1596: do_authentication2(authctxt);
1.98 markus 1597: } else {
1598: do_ssh1_kex();
1.278 markus 1599: do_authentication(authctxt);
1.98 markus 1600: }
1.237 markus 1601: /*
1602: * If we use privilege separation, the unprivileged child transfers
1603: * the current keystate and exits
1604: */
1605: if (use_privsep) {
1.242 mouring 1606: mm_send_keystate(pmonitor);
1.231 provos 1607: exit(0);
1.237 markus 1608: }
1.231 provos 1609:
1610: authenticated:
1.234 markus 1611: /*
1.231 provos 1612: * In privilege separation, we fork another child and prepare
1613: * file descriptor passing.
1614: */
1615: if (use_privsep) {
1.237 markus 1616: privsep_postauth(authctxt);
1617: /* the monitor process [priv] will not return */
1.231 provos 1618: if (!compat20)
1619: destroy_sensitive_data();
1620: }
1.230 provos 1621:
1.278 markus 1622: /* Start session. */
1.230 provos 1623: do_authenticated(authctxt);
1624:
1.64 markus 1625: /* The connection has been terminated. */
1626: verbose("Closing connection to %.100s", remote_ip);
1627: packet_close();
1.231 provos 1628:
1629: if (use_privsep)
1630: mm_terminate();
1631:
1.64 markus 1632: exit(0);
1.1 deraadt 1633: }
1634:
1.65 deraadt 1635: /*
1.229 markus 1636: * Decrypt session_key_int using our private server key and private host key
1637: * (key with larger modulus first).
1638: */
1.231 provos 1639: int
1.229 markus 1640: ssh1_session_key(BIGNUM *session_key_int)
1641: {
1642: int rsafail = 0;
1643:
1644: if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1645: /* Server key has bigger modulus. */
1646: if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1647: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1648: fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1649: get_remote_ipaddr(),
1650: BN_num_bits(sensitive_data.server_key->rsa->n),
1651: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1652: SSH_KEY_BITS_RESERVED);
1653: }
1654: if (rsa_private_decrypt(session_key_int, session_key_int,
1655: sensitive_data.server_key->rsa) <= 0)
1656: rsafail++;
1657: if (rsa_private_decrypt(session_key_int, session_key_int,
1658: sensitive_data.ssh1_host_key->rsa) <= 0)
1659: rsafail++;
1660: } else {
1661: /* Host key has bigger modulus (or they are equal). */
1662: if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1663: BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1664: fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1665: get_remote_ipaddr(),
1666: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1667: BN_num_bits(sensitive_data.server_key->rsa->n),
1668: SSH_KEY_BITS_RESERVED);
1669: }
1670: if (rsa_private_decrypt(session_key_int, session_key_int,
1671: sensitive_data.ssh1_host_key->rsa) < 0)
1672: rsafail++;
1673: if (rsa_private_decrypt(session_key_int, session_key_int,
1674: sensitive_data.server_key->rsa) < 0)
1675: rsafail++;
1676: }
1677: return (rsafail);
1678: }
1679: /*
1.77 markus 1680: * SSH1 key exchange
1.65 deraadt 1681: */
1.200 itojun 1682: static void
1.142 markus 1683: do_ssh1_kex(void)
1.1 deraadt 1684: {
1.64 markus 1685: int i, len;
1.159 markus 1686: int rsafail = 0;
1.64 markus 1687: BIGNUM *session_key_int;
1.140 markus 1688: u_char session_key[SSH_SESSION_KEY_LENGTH];
1689: u_char cookie[8];
1690: u_int cipher_type, auth_mask, protocol_flags;
1.254 deraadt 1691: u_int32_t rnd = 0;
1.64 markus 1692:
1.66 markus 1693: /*
1694: * Generate check bytes that the client must send back in the user
1695: * packet in order for it to be accepted; this is used to defy ip
1696: * spoofing attacks. Note that this only works against somebody
1697: * doing IP spoofing from a remote machine; any machine on the local
1698: * network can still see outgoing packets and catch the random
1699: * cookie. This only affects rhosts authentication, and this is one
1700: * of the reasons why it is inherently insecure.
1701: */
1.64 markus 1702: for (i = 0; i < 8; i++) {
1703: if (i % 4 == 0)
1.254 deraadt 1704: rnd = arc4random();
1705: cookie[i] = rnd & 0xff;
1706: rnd >>= 8;
1.64 markus 1707: }
1708:
1.66 markus 1709: /*
1710: * Send our public key. We include in the packet 64 bits of random
1711: * data that must be matched in the reply in order to prevent IP
1712: * spoofing.
1713: */
1.64 markus 1714: packet_start(SSH_SMSG_PUBLIC_KEY);
1715: for (i = 0; i < 8; i++)
1.77 markus 1716: packet_put_char(cookie[i]);
1.64 markus 1717:
1718: /* Store our public server RSA key. */
1.134 markus 1719: packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1720: packet_put_bignum(sensitive_data.server_key->rsa->e);
1721: packet_put_bignum(sensitive_data.server_key->rsa->n);
1.64 markus 1722:
1723: /* Store our public host RSA key. */
1.134 markus 1724: packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1725: packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1726: packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1.64 markus 1727:
1728: /* Put protocol flags. */
1729: packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1730:
1731: /* Declare which ciphers we support. */
1.131 markus 1732: packet_put_int(cipher_mask_ssh1(0));
1.64 markus 1733:
1734: /* Declare supported authentication types. */
1735: auth_mask = 0;
1736: if (options.rhosts_rsa_authentication)
1737: auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1738: if (options.rsa_authentication)
1739: auth_mask |= 1 << SSH_AUTH_RSA;
1.196 markus 1740: if (options.challenge_response_authentication == 1)
1.64 markus 1741: auth_mask |= 1 << SSH_AUTH_TIS;
1742: if (options.password_authentication)
1743: auth_mask |= 1 << SSH_AUTH_PASSWORD;
1744: packet_put_int(auth_mask);
1745:
1746: /* Send the packet and wait for it to be sent. */
1747: packet_send();
1748: packet_write_wait();
1749:
1.134 markus 1750: debug("Sent %d bit server key and %d bit host key.",
1751: BN_num_bits(sensitive_data.server_key->rsa->n),
1752: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1.64 markus 1753:
1754: /* Read clients reply (cipher type and session key). */
1.222 markus 1755: packet_read_expect(SSH_CMSG_SESSION_KEY);
1.64 markus 1756:
1.69 markus 1757: /* Get cipher type and check whether we accept this. */
1.64 markus 1758: cipher_type = packet_get_char();
1.69 markus 1759:
1.131 markus 1760: if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1.69 markus 1761: packet_disconnect("Warning: client selects unsupported cipher.");
1.64 markus 1762:
1763: /* Get check bytes from the packet. These must match those we
1764: sent earlier with the public key packet. */
1765: for (i = 0; i < 8; i++)
1.77 markus 1766: if (cookie[i] != packet_get_char())
1.64 markus 1767: packet_disconnect("IP Spoofing check bytes do not match.");
1768:
1769: debug("Encryption type: %.200s", cipher_name(cipher_type));
1770:
1771: /* Get the encrypted integer. */
1.218 markus 1772: if ((session_key_int = BN_new()) == NULL)
1773: fatal("do_ssh1_kex: BN_new failed");
1.221 markus 1774: packet_get_bignum(session_key_int);
1.64 markus 1775:
1776: protocol_flags = packet_get_int();
1777: packet_set_protocol_flags(protocol_flags);
1.220 markus 1778: packet_check_eom();
1.64 markus 1779:
1.229 markus 1780: /* Decrypt session_key_int using host/server keys */
1.231 provos 1781: rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1782:
1.66 markus 1783: /*
1784: * Extract session key from the decrypted integer. The key is in the
1785: * least significant 256 bits of the integer; the first byte of the
1786: * key is in the highest bits.
1787: */
1.159 markus 1788: if (!rsafail) {
1789: BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1790: len = BN_num_bytes(session_key_int);
1791: if (len < 0 || len > sizeof(session_key)) {
1792: error("do_connection: bad session key len from %s: "
1.165 itojun 1793: "session_key_int %d > sizeof(session_key) %lu",
1794: get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1.159 markus 1795: rsafail++;
1796: } else {
1797: memset(session_key, 0, sizeof(session_key));
1798: BN_bn2bin(session_key_int,
1799: session_key + sizeof(session_key) - len);
1.169 markus 1800:
1.291 djm 1801: derive_ssh1_session_id(
1802: sensitive_data.ssh1_host_key->rsa->n,
1803: sensitive_data.server_key->rsa->n,
1804: cookie, session_id);
1.169 markus 1805: /*
1806: * Xor the first 16 bytes of the session key with the
1807: * session id.
1808: */
1809: for (i = 0; i < 16; i++)
1810: session_key[i] ^= session_id[i];
1.159 markus 1811: }
1812: }
1813: if (rsafail) {
1.169 markus 1814: int bytes = BN_num_bytes(session_key_int);
1.227 stevesk 1815: u_char *buf = xmalloc(bytes);
1.169 markus 1816: MD5_CTX md;
1817:
1.264 itojun 1818: logit("do_connection: generating a fake encryption key");
1.169 markus 1819: BN_bn2bin(session_key_int, buf);
1820: MD5_Init(&md);
1821: MD5_Update(&md, buf, bytes);
1822: MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1823: MD5_Final(session_key, &md);
1824: MD5_Init(&md);
1825: MD5_Update(&md, session_key, 16);
1826: MD5_Update(&md, buf, bytes);
1827: MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1828: MD5_Final(session_key + 16, &md);
1829: memset(buf, 0, bytes);
1830: xfree(buf);
1.170 markus 1831: for (i = 0; i < 16; i++)
1832: session_id[i] = session_key[i] ^ session_key[i + 16];
1.159 markus 1833: }
1.231 provos 1834: /* Destroy the private and public keys. No longer. */
1.169 markus 1835: destroy_sensitive_data();
1836:
1.231 provos 1837: if (use_privsep)
1838: mm_ssh1_session_id(session_id);
1839:
1.77 markus 1840: /* Destroy the decrypted integer. It is no longer needed. */
1841: BN_clear_free(session_key_int);
1.64 markus 1842:
1843: /* Set the session key. From this on all communications will be encrypted. */
1844: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1845:
1846: /* Destroy our copy of the session key. It is no longer needed. */
1847: memset(session_key, 0, sizeof(session_key));
1848:
1849: debug("Received session key; encryption turned on.");
1850:
1.243 deraadt 1851: /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1.64 markus 1852: packet_start(SSH_SMSG_SUCCESS);
1853: packet_send();
1854: packet_write_wait();
1.98 markus 1855: }
1856:
1857: /*
1858: * SSH2 key exchange: diffie-hellman-group1-sha1
1859: */
1.200 itojun 1860: static void
1.142 markus 1861: do_ssh2_kex(void)
1.98 markus 1862: {
1863: Kex *kex;
1.102 markus 1864:
1865: if (options.ciphers != NULL) {
1.105 markus 1866: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1.102 markus 1867: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1.166 markus 1868: }
1.184 stevesk 1869: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1870: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1871: myproposal[PROPOSAL_ENC_ALGS_STOC] =
1872: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1873:
1.166 markus 1874: if (options.macs != NULL) {
1875: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1876: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1.246 markus 1877: }
1878: if (!options.compression) {
1879: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1880: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.102 markus 1881: }
1.134 markus 1882: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1883:
1.189 markus 1884: /* start key exchange */
1.188 markus 1885: kex = kex_setup(myproposal);
1.263 markus 1886: kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1.292 djm 1887: kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1.263 markus 1888: kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1.186 markus 1889: kex->server = 1;
1890: kex->client_version_string=client_version_string;
1891: kex->server_version_string=server_version_string;
1892: kex->load_host_key=&get_hostkey_by_type;
1.231 provos 1893: kex->host_key_index=&get_hostkey_index;
1.129 provos 1894:
1.189 markus 1895: xxx_kex = kex;
1896:
1.190 markus 1897: dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1.187 markus 1898:
1899: session_id2 = kex->session_id;
1900: session_id2_len = kex->session_id_len;
1.129 provos 1901:
1902: #ifdef DEBUG_KEXDH
1903: /* send 1st encrypted/maced/compressed message */
1904: packet_start(SSH2_MSG_IGNORE);
1905: packet_put_cstring("markus");
1906: packet_send();
1907: packet_write_wait();
1908: #endif
1.186 markus 1909: debug("KEX done");
1.278 markus 1910: }
1911:
1912: /* server specific fatal cleanup */
1913: void
1914: cleanup_exit(int i)
1915: {
1916: if (the_authctxt)
1917: do_cleanup(the_authctxt);
1918: _exit(i);
1.1 deraadt 1919: }
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