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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Millere4340be2000-09-16 13:29:08 +11005 * This program is the ssh daemon. It listens for connections from clients,
6 * and performs authentication, executes use commands or shell, and forwards
Damien Miller95def091999-11-25 00:26:21 +11007 * information to/from the application to the user client over an encrypted
Damien Millere4340be2000-09-16 13:29:08 +11008 * connection. This can also handle forwarding of X11, TCP/IP, and
9 * authentication agent connections.
Damien Millerefb4afe2000-04-12 18:45:05 +100010 *
Damien Millere4340be2000-09-16 13:29:08 +110011 * 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:
18 *
19 * Copyright (c) 2000 Markus Friedl. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110040 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100041
42#include "includes.h"
Ben Lindstrom31ca54a2001-02-09 02:11:24 +000043RCSID("$OpenBSD: sshd.c,v 1.165 2001/02/08 19:30:53 itojun Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044
Ben Lindstrom226cfa02001-01-22 05:34:40 +000045#include <openssl/dh.h>
46#include <openssl/bn.h>
47#include <openssl/hmac.h>
48
49#include "ssh.h"
50#include "ssh1.h"
51#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100052#include "xmalloc.h"
53#include "rsa.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100054#include "pty.h"
55#include "packet.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100056#include "mpaux.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000057#include "log.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100058#include "servconf.h"
59#include "uidswap.h"
60#include "compat.h"
Damien Millerb38eff82000-04-01 11:09:21 +100061#include "buffer.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000062#include "cipher.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100063#include "kex.h"
Damien Millerb38eff82000-04-01 11:09:21 +100064#include "key.h"
Damien Miller874d77b2000-10-14 16:23:11 +110065#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100066#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +100067#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000068#include "pathnames.h"
69#include "atomicio.h"
70#include "canohost.h"
71#include "auth.h"
72#include "misc.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100073
74#ifdef LIBWRAP
75#include <tcpd.h>
76#include <syslog.h>
77int allow_severity = LOG_INFO;
78int deny_severity = LOG_WARNING;
79#endif /* LIBWRAP */
80
81#ifndef O_NOCTTY
82#define O_NOCTTY 0
83#endif
84
Ben Lindstrom49a79c02000-11-17 03:47:20 +000085#ifdef HAVE___PROGNAME
86extern char *__progname;
87#else
88char *__progname;
89#endif
90
Damien Millerd4a8b7e1999-10-27 13:42:43 +100091/* Server configuration options. */
92ServerOptions options;
93
94/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +000095char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100096
Damien Miller4af51302000-04-16 11:18:38 +100097/*
Damien Miller34132e52000-01-14 15:45:46 +110098 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
99 * Default value is AF_UNSPEC means both IPv4 and IPv6.
100 */
Damien Miller7d80e342000-01-19 14:36:49 +1100101#ifdef IPV4_DEFAULT
102int IPv4or6 = AF_INET;
103#else
Damien Miller34132e52000-01-14 15:45:46 +1100104int IPv4or6 = AF_UNSPEC;
Damien Miller7d80e342000-01-19 14:36:49 +1100105#endif
Damien Miller34132e52000-01-14 15:45:46 +1100106
Damien Miller95def091999-11-25 00:26:21 +1100107/*
108 * Debug mode flag. This can be set on the command line. If debug
109 * mode is enabled, extra debugging output will be sent to the system
110 * log, the daemon will not go to background, and will exit after processing
111 * the first connection.
112 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000113int debug_flag = 0;
114
115/* Flag indicating that the daemon is being started from inetd. */
116int inetd_flag = 0;
117
Ben Lindstromc72745a2000-12-02 19:03:54 +0000118/* Flag indicating that sshd should not detach and become a daemon. */
119int no_daemon_flag = 0;
120
Damien Miller5ce662a1999-11-11 17:57:39 +1100121/* debug goes to stderr unless inetd_flag is set */
122int log_stderr = 0;
123
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000124/* Saved arguments to main(). */
125char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000126int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000127
Damien Miller5428f641999-11-25 11:54:57 +1100128/*
Damien Miller34132e52000-01-14 15:45:46 +1100129 * The sockets that the server is listening; this is used in the SIGHUP
130 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100131 */
Damien Miller34132e52000-01-14 15:45:46 +1100132#define MAX_LISTEN_SOCKS 16
133int listen_socks[MAX_LISTEN_SOCKS];
134int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000135
Damien Miller5428f641999-11-25 11:54:57 +1100136/*
137 * the client's version string, passed by sshd2 in compat mode. if != NULL,
138 * sshd will skip the version-number exchange
139 */
Damien Miller95def091999-11-25 00:26:21 +1100140char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000141char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000142
Damien Miller5428f641999-11-25 11:54:57 +1100143/*
144 * Any really sensitive data in the application is contained in this
145 * structure. The idea is that this structure could be locked into memory so
146 * that the pages do not get written into swap. However, there are some
147 * problems. The private key contains BIGNUMs, and we do not (in principle)
148 * have access to the internals of them, and locking just the structure is
149 * not very useful. Currently, memory locking is not implemented.
150 */
Damien Miller95def091999-11-25 00:26:21 +1100151struct {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100152 Key *server_key; /* empheral server key */
153 Key *ssh1_host_key; /* ssh1 host key */
154 Key **host_keys; /* all private host keys */
155 int have_ssh1_key;
156 int have_ssh2_key;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000157} sensitive_data;
158
Damien Miller5428f641999-11-25 11:54:57 +1100159/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000160 * Flag indicating whether the RSA server key needs to be regenerated.
161 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100162 */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000163int key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000164
165/* This is set to true when SIGHUP is received. */
166int received_sighup = 0;
167
Damien Millerb38eff82000-04-01 11:09:21 +1000168/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000169u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000170
Damien Millereba71ba2000-04-29 23:57:08 +1000171/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000172u_char *session_id2 = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +1000173int session_id2_len = 0;
174
Damien Miller942da032000-08-18 13:59:06 +1000175/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000176u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000177
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000178/* Prototypes for various functions defined later in this file. */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000179void do_ssh1_kex(void);
180void do_ssh2_kex(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100181
Damien Miller874d77b2000-10-14 16:23:11 +1100182void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *);
183void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *);
184
Damien Miller98c7ad62000-03-09 21:27:49 +1100185/*
Damien Miller34132e52000-01-14 15:45:46 +1100186 * Close all listening sockets
187 */
188void
189close_listen_socks(void)
190{
191 int i;
192 for (i = 0; i < num_listen_socks; i++)
193 close(listen_socks[i]);
194 num_listen_socks = -1;
195}
196
197/*
Damien Miller95def091999-11-25 00:26:21 +1100198 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
199 * the effect is to reread the configuration file (and to regenerate
200 * the server key).
201 */
Damien Miller4af51302000-04-16 11:18:38 +1000202void
Damien Miller95def091999-11-25 00:26:21 +1100203sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000204{
Damien Miller95def091999-11-25 00:26:21 +1100205 received_sighup = 1;
206 signal(SIGHUP, sighup_handler);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000207}
208
Damien Miller95def091999-11-25 00:26:21 +1100209/*
210 * Called from the main program after receiving SIGHUP.
211 * Restarts the server.
212 */
Damien Miller4af51302000-04-16 11:18:38 +1000213void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000214sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000215{
Damien Miller95def091999-11-25 00:26:21 +1100216 log("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100217 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +1100218 execv(saved_argv[0], saved_argv);
Kevin Stevesec84dc12000-12-13 17:45:15 +0000219 log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100220 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000221}
222
Damien Miller95def091999-11-25 00:26:21 +1100223/*
224 * Generic signal handler for terminating signals in the master daemon.
225 * These close the listen socket; not closing it seems to cause "Address
226 * already in use" problems on some machines, which is inconvenient.
227 */
Damien Miller4af51302000-04-16 11:18:38 +1000228void
Damien Miller95def091999-11-25 00:26:21 +1100229sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000230{
Damien Miller95def091999-11-25 00:26:21 +1100231 log("Received signal %d; terminating.", sig);
Damien Miller34132e52000-01-14 15:45:46 +1100232 close_listen_socks();
Damien Miller6f83b8e2000-05-02 09:23:45 +1000233 unlink(options.pid_file);
Damien Miller95def091999-11-25 00:26:21 +1100234 exit(255);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000235}
236
Damien Miller95def091999-11-25 00:26:21 +1100237/*
238 * SIGCHLD handler. This is called whenever a child dies. This will then
239 * reap any zombies left by exited c.
240 */
Damien Miller4af51302000-04-16 11:18:38 +1000241void
Damien Miller95def091999-11-25 00:26:21 +1100242main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000243{
Damien Miller95def091999-11-25 00:26:21 +1100244 int save_errno = errno;
245 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100246
Damien Miller95def091999-11-25 00:26:21 +1100247 while (waitpid(-1, &status, WNOHANG) > 0)
248 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100249
Damien Miller95def091999-11-25 00:26:21 +1100250 signal(SIGCHLD, main_sigchld_handler);
251 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000252}
253
Damien Miller95def091999-11-25 00:26:21 +1100254/*
255 * Signal handler for the alarm after the login grace period has expired.
256 */
Damien Miller4af51302000-04-16 11:18:38 +1000257void
Damien Miller95def091999-11-25 00:26:21 +1100258grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000259{
Damien Miller95def091999-11-25 00:26:21 +1100260 /* Close the connection. */
261 packet_close();
262
263 /* Log error and exit. */
264 fatal("Timeout before authentication for %s.", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000265}
266
Damien Miller95def091999-11-25 00:26:21 +1100267/*
Damien Miller95def091999-11-25 00:26:21 +1100268 * Signal handler for the key regeneration alarm. Note that this
269 * alarm only occurs in the daemon waiting for connections, and it does not
270 * do anything with the private key or random state before forking.
271 * Thus there should be no concurrency control/asynchronous execution
272 * problems.
273 */
Damien Miller4af51302000-04-16 11:18:38 +1000274void
Damien Miller0bc1bd82000-11-13 22:57:25 +1100275generate_empheral_server_key(void)
276{
277 log("Generating %s%d bit RSA key.", sensitive_data.server_key ? "new " : "",
278 options.server_key_bits);
279 if (sensitive_data.server_key != NULL)
280 key_free(sensitive_data.server_key);
281 sensitive_data.server_key = key_generate(KEY_RSA1, options.server_key_bits);
282 arc4random_stir();
283 log("RSA key generation complete.");
284}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000285
Damien Miller0bc1bd82000-11-13 22:57:25 +1100286void
Damien Miller95def091999-11-25 00:26:21 +1100287key_regeneration_alarm(int sig)
288{
289 int save_errno = errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000290 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100291 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000292 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100293}
294
Damien Millerb38eff82000-04-01 11:09:21 +1000295void
296sshd_exchange_identification(int sock_in, int sock_out)
297{
Damien Miller78928792000-04-12 20:17:38 +1000298 int i, mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000299 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000300 int major, minor;
Damien Millerb38eff82000-04-01 11:09:21 +1000301 char *s;
302 char buf[256]; /* Must not be larger than remote_version. */
303 char remote_version[256]; /* Must be at least as big as buf. */
304
Damien Miller78928792000-04-12 20:17:38 +1000305 if ((options.protocol & SSH_PROTO_1) &&
306 (options.protocol & SSH_PROTO_2)) {
307 major = PROTOCOL_MAJOR_1;
308 minor = 99;
309 } else if (options.protocol & SSH_PROTO_2) {
310 major = PROTOCOL_MAJOR_2;
311 minor = PROTOCOL_MINOR_2;
312 } else {
313 major = PROTOCOL_MAJOR_1;
314 minor = PROTOCOL_MINOR_1;
315 }
316 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
Damien Millerb38eff82000-04-01 11:09:21 +1000317 server_version_string = xstrdup(buf);
318
319 if (client_version_string == NULL) {
320 /* Send our protocol version identification. */
321 if (atomicio(write, sock_out, server_version_string, strlen(server_version_string))
322 != strlen(server_version_string)) {
323 log("Could not write ident string to %s.", get_remote_ipaddr());
324 fatal_cleanup();
325 }
326
327 /* Read other side\'s version identification. */
328 for (i = 0; i < sizeof(buf) - 1; i++) {
Damien Millerbf7f4662000-06-23 10:16:38 +1000329 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
Damien Millerb38eff82000-04-01 11:09:21 +1000330 log("Did not receive ident string from %s.", get_remote_ipaddr());
331 fatal_cleanup();
332 }
333 if (buf[i] == '\r') {
334 buf[i] = '\n';
335 buf[i + 1] = 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100336 /* Kludge for F-Secure Macintosh < 1.0.2 */
337 if (i == 12 &&
338 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
339 break;
Damien Millerb38eff82000-04-01 11:09:21 +1000340 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000341 }
342 if (buf[i] == '\n') {
343 /* buf[i] == '\n' */
344 buf[i + 1] = 0;
345 break;
346 }
347 }
348 buf[sizeof(buf) - 1] = 0;
349 client_version_string = xstrdup(buf);
350 }
351
352 /*
353 * Check that the versions match. In future this might accept
354 * several versions and set appropriate flags to handle them.
355 */
356 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
357 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000358 s = "Protocol mismatch.\n";
Damien Millerb38eff82000-04-01 11:09:21 +1000359 (void) atomicio(write, sock_out, s, strlen(s));
360 close(sock_in);
361 close(sock_out);
362 log("Bad protocol version identification '%.100s' from %s",
363 client_version_string, get_remote_ipaddr());
364 fatal_cleanup();
365 }
366 debug("Client protocol version %d.%d; client software version %.100s",
367 remote_major, remote_minor, remote_version);
368
Damien Millerefb4afe2000-04-12 18:45:05 +1000369 compat_datafellows(remote_version);
370
Damien Miller78928792000-04-12 20:17:38 +1000371 mismatch = 0;
Damien Millerb38eff82000-04-01 11:09:21 +1000372 switch(remote_major) {
373 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000374 if (remote_minor == 99) {
375 if (options.protocol & SSH_PROTO_2)
376 enable_compat20();
377 else
378 mismatch = 1;
379 break;
380 }
Damien Miller78928792000-04-12 20:17:38 +1000381 if (!(options.protocol & SSH_PROTO_1)) {
382 mismatch = 1;
383 break;
384 }
Damien Millerb38eff82000-04-01 11:09:21 +1000385 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000386 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000387 "is no longer supported. Please install a newer version.");
388 } else if (remote_minor == 3) {
389 /* note that this disables agent-forwarding */
390 enable_compat13();
391 }
Damien Miller78928792000-04-12 20:17:38 +1000392 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000393 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000394 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000395 enable_compat20();
396 break;
397 }
398 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000399 default:
Damien Miller78928792000-04-12 20:17:38 +1000400 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000401 break;
402 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000403 chop(server_version_string);
404 chop(client_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000405 debug("Local version string %.200s", server_version_string);
406
407 if (mismatch) {
408 s = "Protocol major versions differ.\n";
409 (void) atomicio(write, sock_out, s, strlen(s));
410 close(sock_in);
411 close(sock_out);
412 log("Protocol major versions differ for %s: %.200s vs. %.200s",
413 get_remote_ipaddr(),
414 server_version_string, client_version_string);
415 fatal_cleanup();
416 }
Damien Millereba71ba2000-04-29 23:57:08 +1000417 if (compat20)
418 packet_set_ssh2_format();
419}
420
421
Damien Miller0bc1bd82000-11-13 22:57:25 +1100422/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000423void
424destroy_sensitive_data(void)
425{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100426 int i;
427
428 if (sensitive_data.server_key) {
429 key_free(sensitive_data.server_key);
430 sensitive_data.server_key = NULL;
431 }
Kevin Stevesef4eea92001-02-05 12:42:17 +0000432 for(i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100433 if (sensitive_data.host_keys[i]) {
434 key_free(sensitive_data.host_keys[i]);
435 sensitive_data.host_keys[i] = NULL;
436 }
437 }
438 sensitive_data.ssh1_host_key = NULL;
439}
440Key *
441load_private_key_autodetect(const char *filename)
442{
443 struct stat st;
444 int type;
445 Key *public, *private;
446
447 if (stat(filename, &st) < 0) {
448 perror(filename);
449 return NULL;
450 }
451 /*
452 * try to load the public key. right now this only works for RSA1,
453 * since SSH2 keys are fully encrypted
454 */
455 type = KEY_RSA1;
456 public = key_new(type);
457 if (!load_public_key(filename, public, NULL)) {
458 /* ok, so we will assume this is 'some' key */
459 type = KEY_UNSPEC;
460 }
461 key_free(public);
462
463 /* Ok, try key with empty passphrase */
464 private = key_new(type);
465 if (load_private_key(filename, "", private, NULL)) {
466 debug("load_private_key_autodetect: type %d %s",
467 private->type, key_type(private));
468 return private;
469 }
470 key_free(private);
471 return NULL;
472}
473
474char *
475list_hostkey_types(void)
476{
477 static char buf[1024];
478 int i;
479 buf[0] = '\0';
480 for(i = 0; i < options.num_host_key_files; i++) {
481 Key *key = sensitive_data.host_keys[i];
482 if (key == NULL)
483 continue;
484 switch(key->type) {
485 case KEY_RSA:
486 case KEY_DSA:
487 strlcat(buf, key_ssh_name(key), sizeof buf);
488 strlcat(buf, ",", sizeof buf);
489 break;
490 }
491 }
492 i = strlen(buf);
493 if (i > 0 && buf[i-1] == ',')
494 buf[i-1] = '\0';
495 debug("list_hostkey_types: %s", buf);
496 return buf;
497}
498
499Key *
500get_hostkey_by_type(int type)
501{
502 int i;
503 for(i = 0; i < options.num_host_key_files; i++) {
504 Key *key = sensitive_data.host_keys[i];
505 if (key != NULL && key->type == type)
506 return key;
507 }
508 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000509}
510
Damien Miller942da032000-08-18 13:59:06 +1000511/*
512 * returns 1 if connection should be dropped, 0 otherwise.
513 * dropping starts at connection #max_startups_begin with a probability
514 * of (max_startups_rate/100). the probability increases linearly until
515 * all connections are dropped for startups > max_startups
516 */
517int
518drop_connection(int startups)
519{
520 double p, r;
521
522 if (startups < options.max_startups_begin)
523 return 0;
524 if (startups >= options.max_startups)
525 return 1;
526 if (options.max_startups_rate == 100)
527 return 1;
528
529 p = 100 - options.max_startups_rate;
530 p *= startups - options.max_startups_begin;
531 p /= (double) (options.max_startups - options.max_startups_begin);
532 p += options.max_startups_rate;
533 p /= 100.0;
534 r = arc4random() / (double) UINT_MAX;
535
536 debug("drop_connection: p %g, r %g", p, r);
537 return (r < p) ? 1 : 0;
538}
539
Damien Miller37023962000-07-11 17:31:38 +1000540int *startup_pipes = NULL; /* options.max_startup sized array of fd ints */
541int startup_pipe; /* in child */
542
Damien Miller95def091999-11-25 00:26:21 +1100543/*
544 * Main program for the daemon.
545 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000546int
547main(int ac, char **av)
548{
Damien Miller95def091999-11-25 00:26:21 +1100549 extern char *optarg;
550 extern int optind;
Damien Miller37023962000-07-11 17:31:38 +1000551 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
Damien Miller166fca82000-04-20 07:42:21 +1000552 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +1100553 socklen_t fromlen;
Damien Miller34132e52000-01-14 15:45:46 +1100554 fd_set *fdset;
555 struct sockaddr_storage from;
Damien Miller95def091999-11-25 00:26:21 +1100556 const char *remote_ip;
557 int remote_port;
Damien Miller95def091999-11-25 00:26:21 +1100558 FILE *f;
559 struct linger linger;
Damien Miller34132e52000-01-14 15:45:46 +1100560 struct addrinfo *ai;
561 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
562 int listen_sock, maxfd;
Damien Miller37023962000-07-11 17:31:38 +1000563 int startup_p[2];
564 int startups = 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000565 int ret, key_used = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000566
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000567 __progname = get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +1000568 init_rng();
569
Kevin Stevesec84dc12000-12-13 17:45:15 +0000570 /* Save argv. */
Damien Millerb8c656e2000-06-28 15:22:41 +1000571 saved_argc = ac;
Damien Miller95def091999-11-25 00:26:21 +1100572 saved_argv = av;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000573
Damien Miller95def091999-11-25 00:26:21 +1100574 /* Initialize configuration options to their default values. */
575 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000576
Damien Miller95def091999-11-25 00:26:21 +1100577 /* Parse command-line arguments. */
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000578 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDiqQ46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +1100579 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +1100580 case '4':
581 IPv4or6 = AF_INET;
582 break;
583 case '6':
584 IPv4or6 = AF_INET6;
585 break;
Damien Miller95def091999-11-25 00:26:21 +1100586 case 'f':
587 config_file_name = optarg;
588 break;
589 case 'd':
Damien Millere4340be2000-09-16 13:29:08 +1100590 if (0 == debug_flag) {
591 debug_flag = 1;
592 options.log_level = SYSLOG_LEVEL_DEBUG1;
593 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
594 options.log_level++;
595 } else {
596 fprintf(stderr, "Too high debugging level.\n");
597 exit(1);
598 }
Damien Miller95def091999-11-25 00:26:21 +1100599 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000600 case 'D':
601 no_daemon_flag = 1;
602 break;
Damien Miller95def091999-11-25 00:26:21 +1100603 case 'i':
604 inetd_flag = 1;
605 break;
606 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +0000607 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +1100608 break;
609 case 'q':
610 options.log_level = SYSLOG_LEVEL_QUIET;
611 break;
612 case 'b':
613 options.server_key_bits = atoi(optarg);
614 break;
615 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +1100616 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +1100617 if (options.num_ports >= MAX_PORTS) {
618 fprintf(stderr, "too many ports.\n");
619 exit(1);
620 }
Damien Miller34132e52000-01-14 15:45:46 +1100621 options.ports[options.num_ports++] = atoi(optarg);
Damien Miller95def091999-11-25 00:26:21 +1100622 break;
623 case 'g':
624 options.login_grace_time = atoi(optarg);
625 break;
626 case 'k':
627 options.key_regeneration_time = atoi(optarg);
628 break;
629 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +1100630 if (options.num_host_key_files >= MAX_HOSTKEYS) {
631 fprintf(stderr, "too many host keys.\n");
632 exit(1);
633 }
634 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +1100635 break;
636 case 'V':
637 client_version_string = optarg;
638 /* only makes sense with inetd_flag, i.e. no listen() */
639 inetd_flag = 1;
640 break;
Damien Miller942da032000-08-18 13:59:06 +1000641 case 'u':
642 utmp_len = atoi(optarg);
643 break;
Damien Miller95def091999-11-25 00:26:21 +1100644 case '?':
645 default:
646 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
Kevin Stevesec84dc12000-12-13 17:45:15 +0000647 fprintf(stderr, "Usage: %s [options]\n", __progname);
Damien Miller95def091999-11-25 00:26:21 +1100648 fprintf(stderr, "Options:\n");
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000649 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
Damien Millere4340be2000-09-16 13:29:08 +1100650 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
Damien Miller95def091999-11-25 00:26:21 +1100651 fprintf(stderr, " -i Started from inetd\n");
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000652 fprintf(stderr, " -D Do not fork into daemon mode\n");
Damien Miller95def091999-11-25 00:26:21 +1100653 fprintf(stderr, " -q Quiet (no logging)\n");
654 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
655 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
Ben Lindstromd26dcf32001-01-06 15:18:16 +0000656 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
Damien Miller95def091999-11-25 00:26:21 +1100657 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
658 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000659 _PATH_HOST_KEY_FILE);
Damien Miller942da032000-08-18 13:59:06 +1000660 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
Damien Miller34132e52000-01-14 15:45:46 +1100661 fprintf(stderr, " -4 Use IPv4 only\n");
662 fprintf(stderr, " -6 Use IPv6 only\n");
Damien Miller95def091999-11-25 00:26:21 +1100663 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000664 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000665 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000666
Damien Miller34132e52000-01-14 15:45:46 +1100667 /*
668 * Force logging to stderr until we have loaded the private host
669 * key (unless started from inetd)
670 */
Kevin Stevesec84dc12000-12-13 17:45:15 +0000671 log_init(__progname,
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000672 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
Damien Miller34132e52000-01-14 15:45:46 +1100673 options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromd5390202001-01-29 08:07:43 +0000674 !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +1100675
Damien Miller95def091999-11-25 00:26:21 +1100676 /* Read server configuration options from the configuration file. */
677 read_server_config(&options, config_file_name);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000678
Damien Miller95def091999-11-25 00:26:21 +1100679 /* Fill in default values for those options not explicitly set. */
680 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000681
Damien Miller95def091999-11-25 00:26:21 +1100682 /* Check that there are no remaining arguments. */
683 if (optind < ac) {
684 fprintf(stderr, "Extra argument %s.\n", av[optind]);
685 exit(1);
686 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000687
Damien Miller95def091999-11-25 00:26:21 +1100688 debug("sshd version %.100s", SSH_VERSION);
Damien Miller2ccf6611999-11-15 15:25:10 +1100689
Damien Miller0bc1bd82000-11-13 22:57:25 +1100690 /* load private host keys */
691 sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*));
Ben Lindstrom46c16222000-12-22 01:43:59 +0000692 for(i = 0; i < options.num_host_key_files; i++)
693 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100694 sensitive_data.server_key = NULL;
695 sensitive_data.ssh1_host_key = NULL;
696 sensitive_data.have_ssh1_key = 0;
697 sensitive_data.have_ssh2_key = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000698
Damien Miller0bc1bd82000-11-13 22:57:25 +1100699 for(i = 0; i < options.num_host_key_files; i++) {
700 Key *key = load_private_key_autodetect(options.host_key_files[i]);
701 if (key == NULL) {
702 error("Could not load host key: %.200s: %.100s",
703 options.host_key_files[i], strerror(errno));
704 continue;
705 }
706 switch(key->type){
707 case KEY_RSA1:
708 sensitive_data.ssh1_host_key = key;
709 sensitive_data.have_ssh1_key = 1;
710 break;
711 case KEY_RSA:
712 case KEY_DSA:
713 sensitive_data.have_ssh2_key = 1;
714 break;
715 }
716 sensitive_data.host_keys[i] = key;
717 }
718 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
719 log("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +1000720 options.protocol &= ~SSH_PROTO_1;
721 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100722 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
723 log("Disabling protocol version 2. Could not load host key");
724 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +1000725 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +0000726 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Millereba71ba2000-04-29 23:57:08 +1000727 log("sshd: no hostkeys available -- exiting.\n");
Damien Miller95def091999-11-25 00:26:21 +1100728 exit(1);
729 }
Damien Miller95def091999-11-25 00:26:21 +1100730
Damien Millereba71ba2000-04-29 23:57:08 +1000731 /* Check certain values for sanity. */
732 if (options.protocol & SSH_PROTO_1) {
733 if (options.server_key_bits < 512 ||
734 options.server_key_bits > 32768) {
735 fprintf(stderr, "Bad server key size.\n");
736 exit(1);
737 }
738 /*
739 * Check that server and host key lengths differ sufficiently. This
740 * is necessary to make double encryption work with rsaref. Oh, I
741 * hate software patents. I dont know if this can go? Niels
742 */
743 if (options.server_key_bits >
Damien Miller0bc1bd82000-11-13 22:57:25 +1100744 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED &&
Damien Millereba71ba2000-04-29 23:57:08 +1000745 options.server_key_bits <
Damien Miller0bc1bd82000-11-13 22:57:25 +1100746 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +1000747 options.server_key_bits =
Damien Miller0bc1bd82000-11-13 22:57:25 +1100748 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +1000749 debug("Forcing server key to %d bits to make it differ from host key.",
750 options.server_key_bits);
751 }
752 }
753
Damien Miller78315eb2000-09-29 23:01:36 +1100754#ifdef HAVE_SCO_PROTECTED_PW
755 (void) set_auth_parameters(ac, av);
756#endif
757
Damien Millereba71ba2000-04-29 23:57:08 +1000758 /* Initialize the log (it is reinitialized below in case we forked). */
Damien Miller95def091999-11-25 00:26:21 +1100759 if (debug_flag && !inetd_flag)
760 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +0000761 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +1100762
Damien Millereba71ba2000-04-29 23:57:08 +1000763 /*
764 * If not in debugging mode, and not started from inetd, disconnect
765 * from the controlling terminal, and fork. The original process
766 * exits.
767 */
Ben Lindstromc72745a2000-12-02 19:03:54 +0000768 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +1100769#ifdef TIOCNOTTY
770 int fd;
771#endif /* TIOCNOTTY */
772 if (daemon(0, 0) < 0)
773 fatal("daemon() failed: %.200s", strerror(errno));
774
775 /* Disconnect from the controlling tty. */
776#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000777 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +1100778 if (fd >= 0) {
779 (void) ioctl(fd, TIOCNOTTY, NULL);
780 close(fd);
781 }
782#endif /* TIOCNOTTY */
783 }
784 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +0000785 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +1100786
Damien Miller95def091999-11-25 00:26:21 +1100787 /* Initialize the random number generator. */
788 arc4random_stir();
789
790 /* Chdir to the root directory so that the current disk can be
791 unmounted if desired. */
792 chdir("/");
793
Damien Miller95def091999-11-25 00:26:21 +1100794 /* Start listening for a socket, unless started from inetd. */
795 if (inetd_flag) {
796 int s1, s2;
797 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
798 s2 = dup(s1);
799 sock_in = dup(0);
800 sock_out = dup(1);
Damien Miller994cf142000-07-21 10:19:44 +1000801 startup_pipe = -1;
Damien Millereba71ba2000-04-29 23:57:08 +1000802 /*
803 * We intentionally do not close the descriptors 0, 1, and 2
804 * as our code for setting the descriptors won\'t work if
805 * ttyfd happens to be one of those.
806 */
Damien Miller95def091999-11-25 00:26:21 +1100807 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100808 if (options.protocol & SSH_PROTO_1)
809 generate_empheral_server_key();
Damien Miller95def091999-11-25 00:26:21 +1100810 } else {
Damien Miller34132e52000-01-14 15:45:46 +1100811 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
812 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
813 continue;
814 if (num_listen_socks >= MAX_LISTEN_SOCKS)
815 fatal("Too many listen sockets. "
816 "Enlarge MAX_LISTEN_SOCKS");
817 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
818 ntop, sizeof(ntop), strport, sizeof(strport),
819 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
820 error("getnameinfo failed");
821 continue;
822 }
823 /* Create socket for listening. */
824 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
825 if (listen_sock < 0) {
826 /* kernel may not support ipv6 */
827 verbose("socket: %.100s", strerror(errno));
828 continue;
829 }
830 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
831 error("listen_sock O_NONBLOCK: %s", strerror(errno));
832 close(listen_sock);
833 continue;
834 }
835 /*
836 * Set socket options. We try to make the port
837 * reusable and have it close as fast as possible
838 * without waiting in unnecessary wait states on
839 * close.
840 */
841 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
842 (void *) &on, sizeof(on));
843 linger.l_onoff = 1;
844 linger.l_linger = 5;
845 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
846 (void *) &linger, sizeof(linger));
Damien Miller95def091999-11-25 00:26:21 +1100847
Damien Miller34132e52000-01-14 15:45:46 +1100848 debug("Bind to port %s on %s.", strport, ntop);
Damien Miller95def091999-11-25 00:26:21 +1100849
Damien Miller34132e52000-01-14 15:45:46 +1100850 /* Bind the socket to the desired port. */
Damien Miller3c7eeb22000-03-03 22:35:33 +1100851 if ((bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) &&
852 (!ai->ai_next)) {
Damien Miller34132e52000-01-14 15:45:46 +1100853 error("Bind to port %s on %s failed: %.200s.",
854 strport, ntop, strerror(errno));
855 close(listen_sock);
856 continue;
857 }
858 listen_socks[num_listen_socks] = listen_sock;
859 num_listen_socks++;
Damien Miller95def091999-11-25 00:26:21 +1100860
Damien Miller34132e52000-01-14 15:45:46 +1100861 /* Start listening on the port. */
862 log("Server listening on %s port %s.", ntop, strport);
863 if (listen(listen_sock, 5) < 0)
864 fatal("listen: %.100s", strerror(errno));
865
Damien Miller95def091999-11-25 00:26:21 +1100866 }
Damien Miller34132e52000-01-14 15:45:46 +1100867 freeaddrinfo(options.listen_addrs);
868
869 if (!num_listen_socks)
870 fatal("Cannot bind any address.");
871
Damien Miller95def091999-11-25 00:26:21 +1100872 if (!debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +1100873 /*
Ben Lindstrom7ad97102000-12-06 01:42:49 +0000874 * Record our pid in /var/run/sshd.pid to make it
875 * easier to kill the correct sshd. We don't want to
876 * do this before the bind above because the bind will
Damien Miller5428f641999-11-25 11:54:57 +1100877 * fail if there already is a daemon, and this will
878 * overwrite any old pid in the file.
879 */
Damien Millerbac2d8a2000-09-05 16:13:06 +1100880 f = fopen(options.pid_file, "wb");
Damien Miller95def091999-11-25 00:26:21 +1100881 if (f) {
Ben Lindstrom46c16222000-12-22 01:43:59 +0000882 fprintf(f, "%u\n", (u_int) getpid());
Damien Miller95def091999-11-25 00:26:21 +1100883 fclose(f);
884 }
885 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000886 if (options.protocol & SSH_PROTO_1)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100887 generate_empheral_server_key();
Damien Miller95def091999-11-25 00:26:21 +1100888
Damien Miller95def091999-11-25 00:26:21 +1100889 /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
890 signal(SIGHUP, sighup_handler);
Damien Miller37023962000-07-11 17:31:38 +1000891
Damien Miller95def091999-11-25 00:26:21 +1100892 signal(SIGTERM, sigterm_handler);
893 signal(SIGQUIT, sigterm_handler);
894
895 /* Arrange SIGCHLD to be caught. */
896 signal(SIGCHLD, main_sigchld_handler);
897
Damien Miller34132e52000-01-14 15:45:46 +1100898 /* setup fd set for listen */
Damien Miller37023962000-07-11 17:31:38 +1000899 fdset = NULL;
Damien Miller34132e52000-01-14 15:45:46 +1100900 maxfd = 0;
901 for (i = 0; i < num_listen_socks; i++)
902 if (listen_socks[i] > maxfd)
903 maxfd = listen_socks[i];
Damien Miller37023962000-07-11 17:31:38 +1000904 /* pipes connected to unauthenticated childs */
905 startup_pipes = xmalloc(options.max_startups * sizeof(int));
906 for (i = 0; i < options.max_startups; i++)
907 startup_pipes[i] = -1;
Damien Miller34132e52000-01-14 15:45:46 +1100908
Damien Miller5428f641999-11-25 11:54:57 +1100909 /*
910 * Stay listening for connections until the system crashes or
911 * the daemon is killed with a signal.
912 */
Damien Miller95def091999-11-25 00:26:21 +1100913 for (;;) {
914 if (received_sighup)
915 sighup_restart();
Damien Miller37023962000-07-11 17:31:38 +1000916 if (fdset != NULL)
917 xfree(fdset);
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000918 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
Damien Miller37023962000-07-11 17:31:38 +1000919 fdset = (fd_set *)xmalloc(fdsetsz);
Damien Miller34132e52000-01-14 15:45:46 +1100920 memset(fdset, 0, fdsetsz);
Damien Miller37023962000-07-11 17:31:38 +1000921
Damien Miller34132e52000-01-14 15:45:46 +1100922 for (i = 0; i < num_listen_socks; i++)
923 FD_SET(listen_socks[i], fdset);
Damien Miller37023962000-07-11 17:31:38 +1000924 for (i = 0; i < options.max_startups; i++)
925 if (startup_pipes[i] != -1)
926 FD_SET(startup_pipes[i], fdset);
927
928 /* Wait in select until there is a connection. */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000929 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
930 if (ret < 0 && errno != EINTR)
931 error("select: %.100s", strerror(errno));
932 if (key_used && key_do_regen) {
933 generate_empheral_server_key();
934 key_used = 0;
935 key_do_regen = 0;
Damien Miller34132e52000-01-14 15:45:46 +1100936 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000937 if (ret < 0)
938 continue;
939
Damien Miller37023962000-07-11 17:31:38 +1000940 for (i = 0; i < options.max_startups; i++)
941 if (startup_pipes[i] != -1 &&
942 FD_ISSET(startup_pipes[i], fdset)) {
943 /*
944 * the read end of the pipe is ready
945 * if the child has closed the pipe
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000946 * after successful authentication
Damien Miller37023962000-07-11 17:31:38 +1000947 * or if the child has died
948 */
949 close(startup_pipes[i]);
950 startup_pipes[i] = -1;
951 startups--;
952 }
Damien Miller34132e52000-01-14 15:45:46 +1100953 for (i = 0; i < num_listen_socks; i++) {
954 if (!FD_ISSET(listen_socks[i], fdset))
Damien Miller95def091999-11-25 00:26:21 +1100955 continue;
Damien Miller37023962000-07-11 17:31:38 +1000956 fromlen = sizeof(from);
957 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
958 &fromlen);
959 if (newsock < 0) {
960 if (errno != EINTR && errno != EWOULDBLOCK)
961 error("accept: %.100s", strerror(errno));
962 continue;
963 }
964 if (fcntl(newsock, F_SETFL, 0) < 0) {
965 error("newsock del O_NONBLOCK: %s", strerror(errno));
966 continue;
967 }
Damien Miller942da032000-08-18 13:59:06 +1000968 if (drop_connection(startups) == 1) {
969 debug("drop connection #%d", startups);
Damien Miller37023962000-07-11 17:31:38 +1000970 close(newsock);
971 continue;
972 }
973 if (pipe(startup_p) == -1) {
974 close(newsock);
975 continue;
976 }
977
978 for (j = 0; j < options.max_startups; j++)
979 if (startup_pipes[j] == -1) {
980 startup_pipes[j] = startup_p[0];
981 if (maxfd < startup_p[0])
982 maxfd = startup_p[0];
983 startups++;
984 break;
985 }
Kevin Stevesef4eea92001-02-05 12:42:17 +0000986
Damien Miller5428f641999-11-25 11:54:57 +1100987 /*
Damien Miller37023962000-07-11 17:31:38 +1000988 * Got connection. Fork a child to handle it, unless
989 * we are in debugging mode.
Damien Miller5428f641999-11-25 11:54:57 +1100990 */
Damien Miller37023962000-07-11 17:31:38 +1000991 if (debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +1100992 /*
Damien Miller37023962000-07-11 17:31:38 +1000993 * In debugging mode. Close the listening
994 * socket, and start processing the
995 * connection without forking.
Damien Miller5428f641999-11-25 11:54:57 +1100996 */
Damien Miller37023962000-07-11 17:31:38 +1000997 debug("Server will not fork when running in debugging mode.");
Damien Miller34132e52000-01-14 15:45:46 +1100998 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +1100999 sock_in = newsock;
1000 sock_out = newsock;
Damien Miller4d97ba22000-07-11 18:15:50 +10001001 startup_pipe = -1;
Damien Miller182ee6e2000-07-12 09:45:27 +10001002 pid = getpid();
Damien Miller95def091999-11-25 00:26:21 +11001003 break;
Damien Miller37023962000-07-11 17:31:38 +10001004 } else {
1005 /*
1006 * Normal production daemon. Fork, and have
1007 * the child process the connection. The
1008 * parent continues listening.
1009 */
1010 if ((pid = fork()) == 0) {
1011 /*
1012 * Child. Close the listening and max_startup
1013 * sockets. Start using the accepted socket.
1014 * Reinitialize logging (since our pid has
1015 * changed). We break out of the loop to handle
1016 * the connection.
1017 */
1018 startup_pipe = startup_p[1];
1019 for (j = 0; j < options.max_startups; j++)
1020 if (startup_pipes[j] != -1)
1021 close(startup_pipes[j]);
1022 close_listen_socks();
1023 sock_in = newsock;
1024 sock_out = newsock;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001025 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller37023962000-07-11 17:31:38 +10001026 break;
1027 }
Damien Miller95def091999-11-25 00:26:21 +11001028 }
Damien Miller37023962000-07-11 17:31:38 +10001029
1030 /* Parent. Stay in the loop. */
1031 if (pid < 0)
1032 error("fork: %.100s", strerror(errno));
1033 else
1034 debug("Forked child %d.", pid);
1035
1036 close(startup_p[1]);
1037
1038 /* Mark that the key has been used (it was "given" to the child). */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001039 if ((options.protocol & SSH_PROTO_1) &&
1040 key_used == 0) {
1041 /* Schedule server key regeneration alarm. */
1042 signal(SIGALRM, key_regeneration_alarm);
1043 alarm(options.key_regeneration_time);
1044 key_used = 1;
1045 }
Damien Miller37023962000-07-11 17:31:38 +10001046
1047 arc4random_stir();
1048
1049 /* Close the new socket (the child is now taking care of it). */
1050 close(newsock);
Damien Miller95def091999-11-25 00:26:21 +11001051 }
Damien Miller34132e52000-01-14 15:45:46 +11001052 /* child process check (or debug mode) */
1053 if (num_listen_socks < 0)
1054 break;
Damien Miller95def091999-11-25 00:26:21 +11001055 }
1056 }
1057
1058 /* This is the child processing a new connection. */
1059
Damien Miller5428f641999-11-25 11:54:57 +11001060 /*
1061 * Disable the key regeneration alarm. We will not regenerate the
1062 * key since we are no longer in a position to give it to anyone. We
1063 * will not restart on SIGHUP since it no longer makes sense.
1064 */
Damien Miller95def091999-11-25 00:26:21 +11001065 alarm(0);
1066 signal(SIGALRM, SIG_DFL);
1067 signal(SIGHUP, SIG_DFL);
1068 signal(SIGTERM, SIG_DFL);
1069 signal(SIGQUIT, SIG_DFL);
1070 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001071 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001072
Damien Miller5428f641999-11-25 11:54:57 +11001073 /*
1074 * Set socket options for the connection. We want the socket to
1075 * close as fast as possible without waiting for anything. If the
1076 * connection is not a socket, these will do nothing.
1077 */
1078 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
Damien Miller95def091999-11-25 00:26:21 +11001079 linger.l_onoff = 1;
1080 linger.l_linger = 5;
1081 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
1082
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001083 /* Set keepalives if requested. */
1084 if (options.keepalives &&
1085 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
1086 sizeof(on)) < 0)
1087 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1088
Damien Miller5428f641999-11-25 11:54:57 +11001089 /*
1090 * Register our connection. This turns encryption off because we do
1091 * not have a key.
1092 */
Damien Miller95def091999-11-25 00:26:21 +11001093 packet_set_connection(sock_in, sock_out);
1094
1095 remote_port = get_remote_port();
1096 remote_ip = get_remote_ipaddr();
1097
1098 /* Check whether logins are denied from this host. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001099#ifdef LIBWRAP
Damien Miller34132e52000-01-14 15:45:46 +11001100 /* XXX LIBWRAP noes not know about IPv6 */
Damien Miller95def091999-11-25 00:26:21 +11001101 {
1102 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001103
Kevin Stevesec84dc12000-12-13 17:45:15 +00001104 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, NULL);
Damien Miller95def091999-11-25 00:26:21 +11001105 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001106
Damien Miller95def091999-11-25 00:26:21 +11001107 if (!hosts_access(&req)) {
1108 close(sock_in);
1109 close(sock_out);
1110 refuse(&req);
1111 }
Damien Miller34132e52000-01-14 15:45:46 +11001112/*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
Damien Miller95def091999-11-25 00:26:21 +11001113 }
Damien Miller34132e52000-01-14 15:45:46 +11001114#endif /* LIBWRAP */
Damien Miller95def091999-11-25 00:26:21 +11001115 /* Log the connection. */
1116 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001117
Damien Miller5428f641999-11-25 11:54:57 +11001118 /*
1119 * We don\'t want to listen forever unless the other side
1120 * successfully authenticates itself. So we set up an alarm which is
1121 * cleared after successful authentication. A limit of zero
1122 * indicates no limit. Note that we don\'t set the alarm in debugging
1123 * mode; it is just annoying to have the server exit just when you
1124 * are about to discover the bug.
1125 */
Damien Miller95def091999-11-25 00:26:21 +11001126 signal(SIGALRM, grace_alarm_handler);
1127 if (!debug_flag)
1128 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001129
Damien Millerb38eff82000-04-01 11:09:21 +10001130 sshd_exchange_identification(sock_in, sock_out);
Damien Miller5428f641999-11-25 11:54:57 +11001131 /*
Kevin Stevesfcec7f82000-12-15 19:55:48 +00001132 * Check that the connection comes from a privileged port.
1133 * Rhosts-Authentication only makes sense from priviledged
Damien Miller5428f641999-11-25 11:54:57 +11001134 * programs. Of course, if the intruder has root access on his local
1135 * machine, he can connect from any port. So do not use these
1136 * authentication methods from machines that you do not trust.
1137 */
Damien Miller95def091999-11-25 00:26:21 +11001138 if (remote_port >= IPPORT_RESERVED ||
1139 remote_port < IPPORT_RESERVED / 2) {
Kevin Stevesfcec7f82000-12-15 19:55:48 +00001140 debug("Rhosts Authentication disabled, "
Damien Miller0bc1bd82000-11-13 22:57:25 +11001141 "originating port not trusted.");
Damien Miller95def091999-11-25 00:26:21 +11001142 options.rhosts_authentication = 0;
Damien Miller95def091999-11-25 00:26:21 +11001143 }
Damien Miller34132e52000-01-14 15:45:46 +11001144#ifdef KRB4
1145 if (!packet_connection_is_ipv4() &&
1146 options.kerberos_authentication) {
1147 debug("Kerberos Authentication disabled, only available for IPv4.");
1148 options.kerberos_authentication = 0;
1149 }
1150#endif /* KRB4 */
Ben Lindstromf79aeff2001-02-10 21:27:11 +00001151#ifdef AFS
1152 /* If machine has AFS, set process authentication group. */
1153 if (k_hasafs()) {
1154 k_setpag();
1155 k_unlog();
1156 }
1157#endif /* AFS */
Damien Miller34132e52000-01-14 15:45:46 +11001158
Damien Miller95def091999-11-25 00:26:21 +11001159 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001160
Damien Miller396691a2000-01-20 22:44:08 +11001161 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001162 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001163 if (compat20) {
1164 do_ssh2_kex();
1165 do_authentication2();
1166 } else {
1167 do_ssh1_kex();
1168 do_authentication();
1169 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001170
1171#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +11001172 /* Cleanup user's ticket cache file. */
1173 if (options.kerberos_ticket_cleanup)
1174 (void) dest_tkt();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001175#endif /* KRB4 */
1176
Damien Miller95def091999-11-25 00:26:21 +11001177 /* The connection has been terminated. */
1178 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001179
Damien Millerbeb4ba51999-12-28 15:09:35 +11001180#ifdef USE_PAM
Damien Millere72b7af1999-12-30 15:08:44 +11001181 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001182#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001183
Damien Miller95def091999-11-25 00:26:21 +11001184 packet_close();
1185 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001186}
1187
Damien Miller95def091999-11-25 00:26:21 +11001188/*
Damien Miller396691a2000-01-20 22:44:08 +11001189 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001190 */
Damien Miller2ccf6611999-11-15 15:25:10 +11001191void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001192do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001193{
Damien Miller95def091999-11-25 00:26:21 +11001194 int i, len;
Damien Miller396691a2000-01-20 22:44:08 +11001195 int plen, slen;
Damien Miller7650bc62001-01-30 09:27:26 +11001196 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001197 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001198 u_char session_key[SSH_SESSION_KEY_LENGTH];
1199 u_char cookie[8];
1200 u_int cipher_type, auth_mask, protocol_flags;
Damien Miller95def091999-11-25 00:26:21 +11001201 u_int32_t rand = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001202
Damien Miller5428f641999-11-25 11:54:57 +11001203 /*
1204 * Generate check bytes that the client must send back in the user
1205 * packet in order for it to be accepted; this is used to defy ip
1206 * spoofing attacks. Note that this only works against somebody
1207 * doing IP spoofing from a remote machine; any machine on the local
1208 * network can still see outgoing packets and catch the random
1209 * cookie. This only affects rhosts authentication, and this is one
1210 * of the reasons why it is inherently insecure.
1211 */
Damien Miller95def091999-11-25 00:26:21 +11001212 for (i = 0; i < 8; i++) {
1213 if (i % 4 == 0)
1214 rand = arc4random();
Damien Miller396691a2000-01-20 22:44:08 +11001215 cookie[i] = rand & 0xff;
Damien Miller95def091999-11-25 00:26:21 +11001216 rand >>= 8;
1217 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001218
Damien Miller5428f641999-11-25 11:54:57 +11001219 /*
1220 * Send our public key. We include in the packet 64 bits of random
1221 * data that must be matched in the reply in order to prevent IP
1222 * spoofing.
1223 */
Damien Miller95def091999-11-25 00:26:21 +11001224 packet_start(SSH_SMSG_PUBLIC_KEY);
1225 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001226 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001227
Damien Miller95def091999-11-25 00:26:21 +11001228 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001229 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1230 packet_put_bignum(sensitive_data.server_key->rsa->e);
1231 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001232
Damien Miller95def091999-11-25 00:26:21 +11001233 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001234 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1235 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1236 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001237
Damien Miller95def091999-11-25 00:26:21 +11001238 /* Put protocol flags. */
1239 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001240
Damien Miller95def091999-11-25 00:26:21 +11001241 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001242 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001243
1244 /* Declare supported authentication types. */
1245 auth_mask = 0;
1246 if (options.rhosts_authentication)
1247 auth_mask |= 1 << SSH_AUTH_RHOSTS;
1248 if (options.rhosts_rsa_authentication)
1249 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1250 if (options.rsa_authentication)
1251 auth_mask |= 1 << SSH_AUTH_RSA;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001252#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +11001253 if (options.kerberos_authentication)
1254 auth_mask |= 1 << SSH_AUTH_KERBEROS;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001255#endif
1256#ifdef AFS
Damien Miller95def091999-11-25 00:26:21 +11001257 if (options.kerberos_tgt_passing)
1258 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1259 if (options.afs_token_passing)
1260 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001261#endif
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +00001262 if (options.challenge_reponse_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001263 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001264 if (options.password_authentication)
1265 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1266 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001267
Damien Miller95def091999-11-25 00:26:21 +11001268 /* Send the packet and wait for it to be sent. */
1269 packet_send();
1270 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001271
Damien Miller0bc1bd82000-11-13 22:57:25 +11001272 debug("Sent %d bit server key and %d bit host key.",
1273 BN_num_bits(sensitive_data.server_key->rsa->n),
1274 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001275
Damien Miller95def091999-11-25 00:26:21 +11001276 /* Read clients reply (cipher type and session key). */
1277 packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001278
Damien Miller50945fa1999-12-09 10:31:37 +11001279 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11001280 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001281
Damien Miller874d77b2000-10-14 16:23:11 +11001282 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11001283 packet_disconnect("Warning: client selects unsupported cipher.");
1284
Damien Miller95def091999-11-25 00:26:21 +11001285 /* Get check bytes from the packet. These must match those we
1286 sent earlier with the public key packet. */
1287 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001288 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11001289 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001290
Damien Miller95def091999-11-25 00:26:21 +11001291 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001292
Damien Miller95def091999-11-25 00:26:21 +11001293 /* Get the encrypted integer. */
1294 session_key_int = BN_new();
1295 packet_get_bignum(session_key_int, &slen);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001296
Damien Miller95def091999-11-25 00:26:21 +11001297 protocol_flags = packet_get_int();
1298 packet_set_protocol_flags(protocol_flags);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001299
Damien Miller95def091999-11-25 00:26:21 +11001300 packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001301
Damien Miller5428f641999-11-25 11:54:57 +11001302 /*
1303 * Decrypt it using our private server key and private host key (key
1304 * with larger modulus first).
1305 */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001306 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
Damien Miller7650bc62001-01-30 09:27:26 +11001307 /* Server key has bigger modulus. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001308 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1309 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1310 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1311 get_remote_ipaddr(),
1312 BN_num_bits(sensitive_data.server_key->rsa->n),
1313 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1314 SSH_KEY_BITS_RESERVED);
Damien Miller95def091999-11-25 00:26:21 +11001315 }
Damien Miller7650bc62001-01-30 09:27:26 +11001316 if (rsa_private_decrypt(session_key_int, session_key_int,
1317 sensitive_data.server_key->rsa) <= 0)
1318 rsafail++;
1319 if (rsa_private_decrypt(session_key_int, session_key_int,
1320 sensitive_data.ssh1_host_key->rsa) <= 0)
1321 rsafail++;
Damien Miller95def091999-11-25 00:26:21 +11001322 } else {
1323 /* Host key has bigger modulus (or they are equal). */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001324 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1325 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1326 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1327 get_remote_ipaddr(),
1328 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1329 BN_num_bits(sensitive_data.server_key->rsa->n),
1330 SSH_KEY_BITS_RESERVED);
Damien Miller95def091999-11-25 00:26:21 +11001331 }
Damien Miller7650bc62001-01-30 09:27:26 +11001332 if (rsa_private_decrypt(session_key_int, session_key_int,
1333 sensitive_data.ssh1_host_key->rsa) < 0)
1334 rsafail++;
1335 if (rsa_private_decrypt(session_key_int, session_key_int,
1336 sensitive_data.server_key->rsa) < 0)
1337 rsafail++;
Damien Miller95def091999-11-25 00:26:21 +11001338 }
Damien Miller356a0b01999-11-08 15:30:59 +11001339
Damien Miller396691a2000-01-20 22:44:08 +11001340 compute_session_id(session_id, cookie,
Damien Miller0bc1bd82000-11-13 22:57:25 +11001341 sensitive_data.ssh1_host_key->rsa->n,
1342 sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001343
Damien Miller396691a2000-01-20 22:44:08 +11001344 /* Destroy the private and public keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +10001345 destroy_sensitive_data();
Damien Miller396691a2000-01-20 22:44:08 +11001346
Damien Miller5428f641999-11-25 11:54:57 +11001347 /*
1348 * Extract session key from the decrypted integer. The key is in the
1349 * least significant 256 bits of the integer; the first byte of the
1350 * key is in the highest bits.
1351 */
Damien Miller7650bc62001-01-30 09:27:26 +11001352 if (!rsafail) {
1353 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1354 len = BN_num_bytes(session_key_int);
1355 if (len < 0 || len > sizeof(session_key)) {
1356 error("do_connection: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001357 "session_key_int %d > sizeof(session_key) %lu",
1358 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11001359 rsafail++;
1360 } else {
1361 memset(session_key, 0, sizeof(session_key));
1362 BN_bn2bin(session_key_int,
1363 session_key + sizeof(session_key) - len);
1364 }
1365 }
1366 if (rsafail) {
1367 log("do_connection: generating a fake encryption key");
1368 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
1369 if (i % 4 == 0)
1370 rand = arc4random();
1371 session_key[i] = rand & 0xff;
1372 rand >>= 8;
1373 }
1374 }
Damien Miller396691a2000-01-20 22:44:08 +11001375 /* Destroy the decrypted integer. It is no longer needed. */
1376 BN_clear_free(session_key_int);
1377
Damien Miller95def091999-11-25 00:26:21 +11001378 /* Xor the first 16 bytes of the session key with the session id. */
1379 for (i = 0; i < 16; i++)
1380 session_key[i] ^= session_id[i];
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001381
Damien Miller95def091999-11-25 00:26:21 +11001382 /* Set the session key. From this on all communications will be encrypted. */
1383 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001384
Damien Miller95def091999-11-25 00:26:21 +11001385 /* Destroy our copy of the session key. It is no longer needed. */
1386 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001387
Damien Miller95def091999-11-25 00:26:21 +11001388 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001389
Damien Miller95def091999-11-25 00:26:21 +11001390 /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1391 packet_start(SSH_SMSG_SUCCESS);
1392 packet_send();
1393 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001394}
Damien Millerefb4afe2000-04-12 18:45:05 +10001395
1396/*
1397 * SSH2 key exchange: diffie-hellman-group1-sha1
1398 */
1399void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001400do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10001401{
1402 Buffer *server_kexinit;
1403 Buffer *client_kexinit;
Damien Miller874d77b2000-10-14 16:23:11 +11001404 int payload_len;
Damien Millerefb4afe2000-04-12 18:45:05 +10001405 int i;
Damien Millerefb4afe2000-04-12 18:45:05 +10001406 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10001407 char *cprop[PROPOSAL_MAX];
Damien Millerefb4afe2000-04-12 18:45:05 +10001408
1409/* KEXINIT */
1410
Damien Miller78928792000-04-12 20:17:38 +10001411 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10001412 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10001413 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1414 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001415 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1416
Damien Millerb1715dc2000-05-30 13:44:51 +10001417 server_kexinit = kex_init(myproposal);
Damien Millerefb4afe2000-04-12 18:45:05 +10001418 client_kexinit = xmalloc(sizeof(*client_kexinit));
1419 buffer_init(client_kexinit);
Damien Millerefb4afe2000-04-12 18:45:05 +10001420
Damien Millerb1715dc2000-05-30 13:44:51 +10001421 /* algorithm negotiation */
1422 kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
1423 kex = kex_choose_conf(cprop, myproposal, 1);
1424 for (i = 0; i < PROPOSAL_MAX; i++)
1425 xfree(cprop[i]);
Damien Millerefb4afe2000-04-12 18:45:05 +10001426
Damien Miller874d77b2000-10-14 16:23:11 +11001427 switch (kex->kex_type) {
1428 case DH_GRP1_SHA1:
1429 ssh_dh1_server(kex, client_kexinit, server_kexinit);
1430 break;
1431 case DH_GEX_SHA1:
1432 ssh_dhgex_server(kex, client_kexinit, server_kexinit);
1433 break;
1434 default:
1435 fatal("Unsupported key exchange %d", kex->kex_type);
1436 }
Damien Millerefb4afe2000-04-12 18:45:05 +10001437
Damien Miller874d77b2000-10-14 16:23:11 +11001438 debug("send SSH2_MSG_NEWKEYS.");
1439 packet_start(SSH2_MSG_NEWKEYS);
1440 packet_send();
1441 packet_write_wait();
1442 debug("done: send SSH2_MSG_NEWKEYS.");
1443
1444 debug("Wait SSH2_MSG_NEWKEYS.");
1445 packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
1446 debug("GOT SSH2_MSG_NEWKEYS.");
1447
1448#ifdef DEBUG_KEXDH
1449 /* send 1st encrypted/maced/compressed message */
1450 packet_start(SSH2_MSG_IGNORE);
1451 packet_put_cstring("markus");
1452 packet_send();
1453 packet_write_wait();
1454#endif
1455
1456 debug("done: KEX2.");
1457}
1458
1459/*
1460 * SSH2 key exchange
1461 */
1462
1463/* diffie-hellman-group1-sha1 */
1464
1465void
1466ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
1467{
1468#ifdef DEBUG_KEXDH
1469 int i;
1470#endif
1471 int payload_len, dlen;
1472 int slen;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001473 u_char *signature = NULL;
1474 u_char *server_host_key_blob = NULL;
1475 u_int sbloblen;
1476 u_int klen, kout;
1477 u_char *kbuf;
1478 u_char *hash;
Damien Miller874d77b2000-10-14 16:23:11 +11001479 BIGNUM *shared_secret = 0;
1480 DH *dh;
1481 BIGNUM *dh_client_pub = 0;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001482 Key *hostkey;
1483
1484 hostkey = get_hostkey_by_type(kex->hostkey_type);
1485 if (hostkey == NULL)
1486 fatal("Unsupported hostkey type %d", kex->hostkey_type);
Damien Miller874d77b2000-10-14 16:23:11 +11001487
1488/* KEXDH */
Kevin Steves6b875862000-12-15 23:31:01 +00001489 /* generate DH key */
1490 dh = dh_new_group1(); /* XXX depends on 'kex' */
1491 dh_gen_key(dh);
1492
Damien Millerefb4afe2000-04-12 18:45:05 +10001493 debug("Wait SSH2_MSG_KEXDH_INIT.");
1494 packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
1495
1496 /* key, cert */
1497 dh_client_pub = BN_new();
1498 if (dh_client_pub == NULL)
1499 fatal("dh_client_pub == NULL");
1500 packet_get_bignum2(dh_client_pub, &dlen);
1501
1502#ifdef DEBUG_KEXDH
1503 fprintf(stderr, "\ndh_client_pub= ");
Damien Miller62cee002000-09-23 17:15:56 +11001504 BN_print_fp(stderr, dh_client_pub);
Damien Millerefb4afe2000-04-12 18:45:05 +10001505 fprintf(stderr, "\n");
1506 debug("bits %d", BN_num_bits(dh_client_pub));
1507#endif
1508
Damien Millerefb4afe2000-04-12 18:45:05 +10001509#ifdef DEBUG_KEXDH
1510 fprintf(stderr, "\np= ");
Damien Miller62cee002000-09-23 17:15:56 +11001511 BN_print_fp(stderr, dh->p);
Damien Millerefb4afe2000-04-12 18:45:05 +10001512 fprintf(stderr, "\ng= ");
Damien Miller62cee002000-09-23 17:15:56 +11001513 bn_print(dh->g);
Damien Millerefb4afe2000-04-12 18:45:05 +10001514 fprintf(stderr, "\npub= ");
Damien Miller62cee002000-09-23 17:15:56 +11001515 BN_print_fp(stderr, dh->pub_key);
Damien Millerefb4afe2000-04-12 18:45:05 +10001516 fprintf(stderr, "\n");
Kevin Stevesef4eea92001-02-05 12:42:17 +00001517 DHparams_print_fp(stderr, dh);
Damien Millerefb4afe2000-04-12 18:45:05 +10001518#endif
Damien Miller78928792000-04-12 20:17:38 +10001519 if (!dh_pub_is_valid(dh, dh_client_pub))
1520 packet_disconnect("bad client public DH value");
Damien Millerefb4afe2000-04-12 18:45:05 +10001521
1522 klen = DH_size(dh);
1523 kbuf = xmalloc(klen);
1524 kout = DH_compute_key(kbuf, dh_client_pub, dh);
1525
1526#ifdef DEBUG_KEXDH
1527 debug("shared secret: len %d/%d", klen, kout);
1528 fprintf(stderr, "shared secret == ");
1529 for (i = 0; i< kout; i++)
1530 fprintf(stderr, "%02x", (kbuf[i])&0xff);
1531 fprintf(stderr, "\n");
1532#endif
1533 shared_secret = BN_new();
1534
1535 BN_bin2bn(kbuf, kout, shared_secret);
1536 memset(kbuf, 0, klen);
1537 xfree(kbuf);
1538
Damien Millereba71ba2000-04-29 23:57:08 +10001539 /* XXX precompute? */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001540 key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
Damien Millerefb4afe2000-04-12 18:45:05 +10001541
1542 /* calc H */ /* XXX depends on 'kex' */
1543 hash = kex_hash(
1544 client_version_string,
1545 server_version_string,
1546 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
1547 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
1548 (char *)server_host_key_blob, sbloblen,
1549 dh_client_pub,
1550 dh->pub_key,
1551 shared_secret
1552 );
1553 buffer_free(client_kexinit);
1554 buffer_free(server_kexinit);
1555 xfree(client_kexinit);
1556 xfree(server_kexinit);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001557 BN_free(dh_client_pub);
Damien Millerefb4afe2000-04-12 18:45:05 +10001558#ifdef DEBUG_KEXDH
Damien Miller4af51302000-04-16 11:18:38 +10001559 fprintf(stderr, "hash == ");
1560 for (i = 0; i< 20; i++)
1561 fprintf(stderr, "%02x", (hash[i])&0xff);
1562 fprintf(stderr, "\n");
Damien Millerefb4afe2000-04-12 18:45:05 +10001563#endif
Damien Millereba71ba2000-04-29 23:57:08 +10001564 /* save session id := H */
1565 /* XXX hashlen depends on KEX */
1566 session_id2_len = 20;
1567 session_id2 = xmalloc(session_id2_len);
1568 memcpy(session_id2, hash, session_id2_len);
1569
Damien Millerefb4afe2000-04-12 18:45:05 +10001570 /* sign H */
Damien Millereba71ba2000-04-29 23:57:08 +10001571 /* XXX hashlen depends on KEX */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001572 key_sign(hostkey, &signature, &slen, hash, 20);
Damien Millereba71ba2000-04-29 23:57:08 +10001573
1574 destroy_sensitive_data();
Damien Millerefb4afe2000-04-12 18:45:05 +10001575
1576 /* send server hostkey, DH pubkey 'f' and singed H */
1577 packet_start(SSH2_MSG_KEXDH_REPLY);
1578 packet_put_string((char *)server_host_key_blob, sbloblen);
Damien Millere247cc42000-05-07 12:03:14 +10001579 packet_put_bignum2(dh->pub_key); /* f */
Damien Millerefb4afe2000-04-12 18:45:05 +10001580 packet_put_string((char *)signature, slen);
1581 packet_send();
Damien Miller8bb73be2000-04-19 16:26:12 +10001582 xfree(signature);
Damien Millereba71ba2000-04-29 23:57:08 +10001583 xfree(server_host_key_blob);
Damien Millerefb4afe2000-04-12 18:45:05 +10001584 packet_write_wait();
1585
1586 kex_derive_keys(kex, hash, shared_secret);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001587 BN_clear_free(shared_secret);
Damien Millerefb4afe2000-04-12 18:45:05 +10001588 packet_set_kex(kex);
1589
1590 /* have keys, free DH */
1591 DH_free(dh);
Damien Miller874d77b2000-10-14 16:23:11 +11001592}
Damien Millerefb4afe2000-04-12 18:45:05 +10001593
Damien Miller874d77b2000-10-14 16:23:11 +11001594/* diffie-hellman-group-exchange-sha1 */
1595
1596void
1597ssh_dhgex_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
1598{
1599#ifdef DEBUG_KEXDH
1600 int i;
1601#endif
1602 int payload_len, dlen;
1603 int slen, nbits;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001604 u_char *signature = NULL;
1605 u_char *server_host_key_blob = NULL;
1606 u_int sbloblen;
1607 u_int klen, kout;
1608 u_char *kbuf;
1609 u_char *hash;
Damien Miller874d77b2000-10-14 16:23:11 +11001610 BIGNUM *shared_secret = 0;
1611 DH *dh;
1612 BIGNUM *dh_client_pub = 0;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001613 Key *hostkey;
1614
1615 hostkey = get_hostkey_by_type(kex->hostkey_type);
1616 if (hostkey == NULL)
1617 fatal("Unsupported hostkey type %d", kex->hostkey_type);
Damien Miller874d77b2000-10-14 16:23:11 +11001618
1619/* KEXDHGEX */
1620 debug("Wait SSH2_MSG_KEX_DH_GEX_REQUEST.");
1621 packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_REQUEST);
1622 nbits = packet_get_int();
1623 dh = choose_dh(nbits);
1624
1625 debug("Sending SSH2_MSG_KEX_DH_GEX_GROUP.");
1626 packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
1627 packet_put_bignum2(dh->p);
1628 packet_put_bignum2(dh->g);
Damien Millerefb4afe2000-04-12 18:45:05 +10001629 packet_send();
1630 packet_write_wait();
Damien Millerefb4afe2000-04-12 18:45:05 +10001631
Kevin Steves6b875862000-12-15 23:31:01 +00001632 /* Compute our exchange value in parallel with the client */
1633
1634 dh_gen_key(dh);
1635
Damien Miller874d77b2000-10-14 16:23:11 +11001636 debug("Wait SSH2_MSG_KEX_DH_GEX_INIT.");
1637 packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_INIT);
1638
1639 /* key, cert */
1640 dh_client_pub = BN_new();
1641 if (dh_client_pub == NULL)
1642 fatal("dh_client_pub == NULL");
1643 packet_get_bignum2(dh_client_pub, &dlen);
Damien Millerefb4afe2000-04-12 18:45:05 +10001644
Damien Miller78928792000-04-12 20:17:38 +10001645#ifdef DEBUG_KEXDH
Damien Miller874d77b2000-10-14 16:23:11 +11001646 fprintf(stderr, "\ndh_client_pub= ");
1647 BN_print_fp(stderr, dh_client_pub);
1648 fprintf(stderr, "\n");
1649 debug("bits %d", BN_num_bits(dh_client_pub));
Damien Miller78928792000-04-12 20:17:38 +10001650#endif
Damien Miller874d77b2000-10-14 16:23:11 +11001651
1652#ifdef DEBUG_KEXDH
1653 fprintf(stderr, "\np= ");
1654 BN_print_fp(stderr, dh->p);
1655 fprintf(stderr, "\ng= ");
1656 bn_print(dh->g);
1657 fprintf(stderr, "\npub= ");
1658 BN_print_fp(stderr, dh->pub_key);
1659 fprintf(stderr, "\n");
Kevin Stevesef4eea92001-02-05 12:42:17 +00001660 DHparams_print_fp(stderr, dh);
Damien Miller874d77b2000-10-14 16:23:11 +11001661#endif
1662 if (!dh_pub_is_valid(dh, dh_client_pub))
1663 packet_disconnect("bad client public DH value");
1664
1665 klen = DH_size(dh);
1666 kbuf = xmalloc(klen);
1667 kout = DH_compute_key(kbuf, dh_client_pub, dh);
1668
1669#ifdef DEBUG_KEXDH
1670 debug("shared secret: len %d/%d", klen, kout);
1671 fprintf(stderr, "shared secret == ");
1672 for (i = 0; i< kout; i++)
1673 fprintf(stderr, "%02x", (kbuf[i])&0xff);
1674 fprintf(stderr, "\n");
1675#endif
1676 shared_secret = BN_new();
1677
1678 BN_bin2bn(kbuf, kout, shared_secret);
1679 memset(kbuf, 0, klen);
1680 xfree(kbuf);
1681
1682 /* XXX precompute? */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001683 key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
Damien Miller874d77b2000-10-14 16:23:11 +11001684
1685 /* calc H */ /* XXX depends on 'kex' */
1686 hash = kex_hash_gex(
1687 client_version_string,
1688 server_version_string,
1689 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
1690 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
1691 (char *)server_host_key_blob, sbloblen,
1692 nbits, dh->p, dh->g,
1693 dh_client_pub,
1694 dh->pub_key,
1695 shared_secret
1696 );
1697 buffer_free(client_kexinit);
1698 buffer_free(server_kexinit);
1699 xfree(client_kexinit);
1700 xfree(server_kexinit);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001701 BN_free(dh_client_pub);
Damien Miller874d77b2000-10-14 16:23:11 +11001702#ifdef DEBUG_KEXDH
1703 fprintf(stderr, "hash == ");
1704 for (i = 0; i< 20; i++)
1705 fprintf(stderr, "%02x", (hash[i])&0xff);
1706 fprintf(stderr, "\n");
1707#endif
1708 /* save session id := H */
1709 /* XXX hashlen depends on KEX */
1710 session_id2_len = 20;
1711 session_id2 = xmalloc(session_id2_len);
1712 memcpy(session_id2, hash, session_id2_len);
1713
1714 /* sign H */
1715 /* XXX hashlen depends on KEX */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001716 key_sign(hostkey, &signature, &slen, hash, 20);
Damien Miller874d77b2000-10-14 16:23:11 +11001717
1718 destroy_sensitive_data();
1719
1720 /* send server hostkey, DH pubkey 'f' and singed H */
1721 packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
1722 packet_put_string((char *)server_host_key_blob, sbloblen);
1723 packet_put_bignum2(dh->pub_key); /* f */
1724 packet_put_string((char *)signature, slen);
1725 packet_send();
1726 xfree(signature);
1727 xfree(server_host_key_blob);
1728 packet_write_wait();
1729
1730 kex_derive_keys(kex, hash, shared_secret);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001731 BN_clear_free(shared_secret);
Damien Miller874d77b2000-10-14 16:23:11 +11001732 packet_set_kex(kex);
1733
1734 /* have keys, free DH */
1735 DH_free(dh);
Damien Millerefb4afe2000-04-12 18:45:05 +10001736}