blob: be046ea65f56c6933ca0e0b2d72213fdb02b4116 [file] [log] [blame]
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 Lindstrom5393f932001-02-15 03:17:13 +000043RCSID("$OpenBSD: sshd.c,v 1.167 2001/02/12 23:26:20 markus 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
Ben Lindstrom5393f932001-02-15 03:17:13 +0000327 /* Read other side's version identification. */
328 memset(buf, 0, sizeof(buf));
Damien Millerb38eff82000-04-01 11:09:21 +1000329 for (i = 0; i < sizeof(buf) - 1; i++) {
Damien Millerbf7f4662000-06-23 10:16:38 +1000330 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
Damien Millerb38eff82000-04-01 11:09:21 +1000331 log("Did not receive ident string from %s.", get_remote_ipaddr());
332 fatal_cleanup();
333 }
334 if (buf[i] == '\r') {
335 buf[i] = '\n';
336 buf[i + 1] = 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100337 /* Kludge for F-Secure Macintosh < 1.0.2 */
338 if (i == 12 &&
339 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
340 break;
Damien Millerb38eff82000-04-01 11:09:21 +1000341 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000342 }
343 if (buf[i] == '\n') {
344 /* buf[i] == '\n' */
345 buf[i + 1] = 0;
346 break;
347 }
348 }
349 buf[sizeof(buf) - 1] = 0;
350 client_version_string = xstrdup(buf);
351 }
352
353 /*
354 * Check that the versions match. In future this might accept
355 * several versions and set appropriate flags to handle them.
356 */
357 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
358 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000359 s = "Protocol mismatch.\n";
Damien Millerb38eff82000-04-01 11:09:21 +1000360 (void) atomicio(write, sock_out, s, strlen(s));
361 close(sock_in);
362 close(sock_out);
363 log("Bad protocol version identification '%.100s' from %s",
364 client_version_string, get_remote_ipaddr());
365 fatal_cleanup();
366 }
367 debug("Client protocol version %d.%d; client software version %.100s",
368 remote_major, remote_minor, remote_version);
369
Damien Millerefb4afe2000-04-12 18:45:05 +1000370 compat_datafellows(remote_version);
371
Damien Miller78928792000-04-12 20:17:38 +1000372 mismatch = 0;
Damien Millerb38eff82000-04-01 11:09:21 +1000373 switch(remote_major) {
374 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000375 if (remote_minor == 99) {
376 if (options.protocol & SSH_PROTO_2)
377 enable_compat20();
378 else
379 mismatch = 1;
380 break;
381 }
Damien Miller78928792000-04-12 20:17:38 +1000382 if (!(options.protocol & SSH_PROTO_1)) {
383 mismatch = 1;
384 break;
385 }
Damien Millerb38eff82000-04-01 11:09:21 +1000386 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000387 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000388 "is no longer supported. Please install a newer version.");
389 } else if (remote_minor == 3) {
390 /* note that this disables agent-forwarding */
391 enable_compat13();
392 }
Damien Miller78928792000-04-12 20:17:38 +1000393 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000394 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000395 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000396 enable_compat20();
397 break;
398 }
399 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000400 default:
Damien Miller78928792000-04-12 20:17:38 +1000401 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000402 break;
403 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000404 chop(server_version_string);
405 chop(client_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000406 debug("Local version string %.200s", server_version_string);
407
408 if (mismatch) {
409 s = "Protocol major versions differ.\n";
410 (void) atomicio(write, sock_out, s, strlen(s));
411 close(sock_in);
412 close(sock_out);
413 log("Protocol major versions differ for %s: %.200s vs. %.200s",
414 get_remote_ipaddr(),
415 server_version_string, client_version_string);
416 fatal_cleanup();
417 }
Damien Millereba71ba2000-04-29 23:57:08 +1000418 if (compat20)
419 packet_set_ssh2_format();
420}
421
422
Damien Miller0bc1bd82000-11-13 22:57:25 +1100423/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000424void
425destroy_sensitive_data(void)
426{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100427 int i;
428
429 if (sensitive_data.server_key) {
430 key_free(sensitive_data.server_key);
431 sensitive_data.server_key = NULL;
432 }
Kevin Stevesef4eea92001-02-05 12:42:17 +0000433 for(i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100434 if (sensitive_data.host_keys[i]) {
435 key_free(sensitive_data.host_keys[i]);
436 sensitive_data.host_keys[i] = NULL;
437 }
438 }
439 sensitive_data.ssh1_host_key = NULL;
440}
441Key *
442load_private_key_autodetect(const char *filename)
443{
444 struct stat st;
445 int type;
446 Key *public, *private;
447
448 if (stat(filename, &st) < 0) {
449 perror(filename);
450 return NULL;
451 }
452 /*
453 * try to load the public key. right now this only works for RSA1,
454 * since SSH2 keys are fully encrypted
455 */
456 type = KEY_RSA1;
457 public = key_new(type);
458 if (!load_public_key(filename, public, NULL)) {
459 /* ok, so we will assume this is 'some' key */
460 type = KEY_UNSPEC;
461 }
462 key_free(public);
463
464 /* Ok, try key with empty passphrase */
465 private = key_new(type);
466 if (load_private_key(filename, "", private, NULL)) {
467 debug("load_private_key_autodetect: type %d %s",
468 private->type, key_type(private));
469 return private;
470 }
471 key_free(private);
472 return NULL;
473}
474
475char *
476list_hostkey_types(void)
477{
478 static char buf[1024];
479 int i;
480 buf[0] = '\0';
481 for(i = 0; i < options.num_host_key_files; i++) {
482 Key *key = sensitive_data.host_keys[i];
483 if (key == NULL)
484 continue;
485 switch(key->type) {
486 case KEY_RSA:
487 case KEY_DSA:
488 strlcat(buf, key_ssh_name(key), sizeof buf);
489 strlcat(buf, ",", sizeof buf);
490 break;
491 }
492 }
493 i = strlen(buf);
494 if (i > 0 && buf[i-1] == ',')
495 buf[i-1] = '\0';
496 debug("list_hostkey_types: %s", buf);
497 return buf;
498}
499
500Key *
501get_hostkey_by_type(int type)
502{
503 int i;
504 for(i = 0; i < options.num_host_key_files; i++) {
505 Key *key = sensitive_data.host_keys[i];
506 if (key != NULL && key->type == type)
507 return key;
508 }
509 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000510}
511
Damien Miller942da032000-08-18 13:59:06 +1000512/*
513 * returns 1 if connection should be dropped, 0 otherwise.
514 * dropping starts at connection #max_startups_begin with a probability
515 * of (max_startups_rate/100). the probability increases linearly until
516 * all connections are dropped for startups > max_startups
517 */
518int
519drop_connection(int startups)
520{
521 double p, r;
522
523 if (startups < options.max_startups_begin)
524 return 0;
525 if (startups >= options.max_startups)
526 return 1;
527 if (options.max_startups_rate == 100)
528 return 1;
529
530 p = 100 - options.max_startups_rate;
531 p *= startups - options.max_startups_begin;
532 p /= (double) (options.max_startups - options.max_startups_begin);
533 p += options.max_startups_rate;
534 p /= 100.0;
535 r = arc4random() / (double) UINT_MAX;
536
537 debug("drop_connection: p %g, r %g", p, r);
538 return (r < p) ? 1 : 0;
539}
540
Damien Miller37023962000-07-11 17:31:38 +1000541int *startup_pipes = NULL; /* options.max_startup sized array of fd ints */
542int startup_pipe; /* in child */
543
Damien Miller95def091999-11-25 00:26:21 +1100544/*
545 * Main program for the daemon.
546 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000547int
548main(int ac, char **av)
549{
Damien Miller95def091999-11-25 00:26:21 +1100550 extern char *optarg;
551 extern int optind;
Damien Miller37023962000-07-11 17:31:38 +1000552 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
Damien Miller166fca82000-04-20 07:42:21 +1000553 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +1100554 socklen_t fromlen;
Damien Miller34132e52000-01-14 15:45:46 +1100555 fd_set *fdset;
556 struct sockaddr_storage from;
Damien Miller95def091999-11-25 00:26:21 +1100557 const char *remote_ip;
558 int remote_port;
Damien Miller95def091999-11-25 00:26:21 +1100559 FILE *f;
560 struct linger linger;
Damien Miller34132e52000-01-14 15:45:46 +1100561 struct addrinfo *ai;
562 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
563 int listen_sock, maxfd;
Damien Miller37023962000-07-11 17:31:38 +1000564 int startup_p[2];
565 int startups = 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000566 int ret, key_used = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000567
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000568 __progname = get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +1000569 init_rng();
570
Kevin Stevesec84dc12000-12-13 17:45:15 +0000571 /* Save argv. */
Damien Millerb8c656e2000-06-28 15:22:41 +1000572 saved_argc = ac;
Damien Miller95def091999-11-25 00:26:21 +1100573 saved_argv = av;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000574
Damien Miller95def091999-11-25 00:26:21 +1100575 /* Initialize configuration options to their default values. */
576 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000577
Damien Miller95def091999-11-25 00:26:21 +1100578 /* Parse command-line arguments. */
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000579 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDiqQ46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +1100580 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +1100581 case '4':
582 IPv4or6 = AF_INET;
583 break;
584 case '6':
585 IPv4or6 = AF_INET6;
586 break;
Damien Miller95def091999-11-25 00:26:21 +1100587 case 'f':
588 config_file_name = optarg;
589 break;
590 case 'd':
Damien Millere4340be2000-09-16 13:29:08 +1100591 if (0 == debug_flag) {
592 debug_flag = 1;
593 options.log_level = SYSLOG_LEVEL_DEBUG1;
594 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
595 options.log_level++;
596 } else {
597 fprintf(stderr, "Too high debugging level.\n");
598 exit(1);
599 }
Damien Miller95def091999-11-25 00:26:21 +1100600 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000601 case 'D':
602 no_daemon_flag = 1;
603 break;
Damien Miller95def091999-11-25 00:26:21 +1100604 case 'i':
605 inetd_flag = 1;
606 break;
607 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +0000608 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +1100609 break;
610 case 'q':
611 options.log_level = SYSLOG_LEVEL_QUIET;
612 break;
613 case 'b':
614 options.server_key_bits = atoi(optarg);
615 break;
616 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +1100617 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +1100618 if (options.num_ports >= MAX_PORTS) {
619 fprintf(stderr, "too many ports.\n");
620 exit(1);
621 }
Damien Miller34132e52000-01-14 15:45:46 +1100622 options.ports[options.num_ports++] = atoi(optarg);
Damien Miller95def091999-11-25 00:26:21 +1100623 break;
624 case 'g':
625 options.login_grace_time = atoi(optarg);
626 break;
627 case 'k':
628 options.key_regeneration_time = atoi(optarg);
629 break;
630 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +1100631 if (options.num_host_key_files >= MAX_HOSTKEYS) {
632 fprintf(stderr, "too many host keys.\n");
633 exit(1);
634 }
635 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +1100636 break;
637 case 'V':
638 client_version_string = optarg;
639 /* only makes sense with inetd_flag, i.e. no listen() */
640 inetd_flag = 1;
641 break;
Damien Miller942da032000-08-18 13:59:06 +1000642 case 'u':
643 utmp_len = atoi(optarg);
644 break;
Damien Miller95def091999-11-25 00:26:21 +1100645 case '?':
646 default:
647 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
Kevin Stevesec84dc12000-12-13 17:45:15 +0000648 fprintf(stderr, "Usage: %s [options]\n", __progname);
Damien Miller95def091999-11-25 00:26:21 +1100649 fprintf(stderr, "Options:\n");
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000650 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
Damien Millere4340be2000-09-16 13:29:08 +1100651 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
Damien Miller95def091999-11-25 00:26:21 +1100652 fprintf(stderr, " -i Started from inetd\n");
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000653 fprintf(stderr, " -D Do not fork into daemon mode\n");
Damien Miller95def091999-11-25 00:26:21 +1100654 fprintf(stderr, " -q Quiet (no logging)\n");
655 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
656 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
Ben Lindstromd26dcf32001-01-06 15:18:16 +0000657 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
Damien Miller95def091999-11-25 00:26:21 +1100658 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
659 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000660 _PATH_HOST_KEY_FILE);
Damien Miller942da032000-08-18 13:59:06 +1000661 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
Damien Miller34132e52000-01-14 15:45:46 +1100662 fprintf(stderr, " -4 Use IPv4 only\n");
663 fprintf(stderr, " -6 Use IPv6 only\n");
Damien Miller95def091999-11-25 00:26:21 +1100664 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000665 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000666 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000667
Damien Miller34132e52000-01-14 15:45:46 +1100668 /*
669 * Force logging to stderr until we have loaded the private host
670 * key (unless started from inetd)
671 */
Kevin Stevesec84dc12000-12-13 17:45:15 +0000672 log_init(__progname,
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000673 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
Damien Miller34132e52000-01-14 15:45:46 +1100674 options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromd5390202001-01-29 08:07:43 +0000675 !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +1100676
Damien Miller95def091999-11-25 00:26:21 +1100677 /* Read server configuration options from the configuration file. */
678 read_server_config(&options, config_file_name);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000679
Damien Miller95def091999-11-25 00:26:21 +1100680 /* Fill in default values for those options not explicitly set. */
681 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000682
Damien Miller95def091999-11-25 00:26:21 +1100683 /* Check that there are no remaining arguments. */
684 if (optind < ac) {
685 fprintf(stderr, "Extra argument %s.\n", av[optind]);
686 exit(1);
687 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000688
Damien Miller95def091999-11-25 00:26:21 +1100689 debug("sshd version %.100s", SSH_VERSION);
Damien Miller2ccf6611999-11-15 15:25:10 +1100690
Damien Miller0bc1bd82000-11-13 22:57:25 +1100691 /* load private host keys */
692 sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*));
Ben Lindstrom46c16222000-12-22 01:43:59 +0000693 for(i = 0; i < options.num_host_key_files; i++)
694 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100695 sensitive_data.server_key = NULL;
696 sensitive_data.ssh1_host_key = NULL;
697 sensitive_data.have_ssh1_key = 0;
698 sensitive_data.have_ssh2_key = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000699
Damien Miller0bc1bd82000-11-13 22:57:25 +1100700 for(i = 0; i < options.num_host_key_files; i++) {
701 Key *key = load_private_key_autodetect(options.host_key_files[i]);
702 if (key == NULL) {
703 error("Could not load host key: %.200s: %.100s",
704 options.host_key_files[i], strerror(errno));
705 continue;
706 }
707 switch(key->type){
708 case KEY_RSA1:
709 sensitive_data.ssh1_host_key = key;
710 sensitive_data.have_ssh1_key = 1;
711 break;
712 case KEY_RSA:
713 case KEY_DSA:
714 sensitive_data.have_ssh2_key = 1;
715 break;
716 }
717 sensitive_data.host_keys[i] = key;
718 }
719 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
720 log("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +1000721 options.protocol &= ~SSH_PROTO_1;
722 }
Damien Miller0bc1bd82000-11-13 22:57:25 +1100723 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
724 log("Disabling protocol version 2. Could not load host key");
725 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +1000726 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +0000727 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Millereba71ba2000-04-29 23:57:08 +1000728 log("sshd: no hostkeys available -- exiting.\n");
Damien Miller95def091999-11-25 00:26:21 +1100729 exit(1);
730 }
Damien Miller95def091999-11-25 00:26:21 +1100731
Damien Millereba71ba2000-04-29 23:57:08 +1000732 /* Check certain values for sanity. */
733 if (options.protocol & SSH_PROTO_1) {
734 if (options.server_key_bits < 512 ||
735 options.server_key_bits > 32768) {
736 fprintf(stderr, "Bad server key size.\n");
737 exit(1);
738 }
739 /*
740 * Check that server and host key lengths differ sufficiently. This
741 * is necessary to make double encryption work with rsaref. Oh, I
742 * hate software patents. I dont know if this can go? Niels
743 */
744 if (options.server_key_bits >
Damien Miller0bc1bd82000-11-13 22:57:25 +1100745 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED &&
Damien Millereba71ba2000-04-29 23:57:08 +1000746 options.server_key_bits <
Damien Miller0bc1bd82000-11-13 22:57:25 +1100747 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +1000748 options.server_key_bits =
Damien Miller0bc1bd82000-11-13 22:57:25 +1100749 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +1000750 debug("Forcing server key to %d bits to make it differ from host key.",
751 options.server_key_bits);
752 }
753 }
754
Damien Miller78315eb2000-09-29 23:01:36 +1100755#ifdef HAVE_SCO_PROTECTED_PW
756 (void) set_auth_parameters(ac, av);
757#endif
758
Damien Millereba71ba2000-04-29 23:57:08 +1000759 /* Initialize the log (it is reinitialized below in case we forked). */
Damien Miller95def091999-11-25 00:26:21 +1100760 if (debug_flag && !inetd_flag)
761 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +0000762 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +1100763
Damien Millereba71ba2000-04-29 23:57:08 +1000764 /*
765 * If not in debugging mode, and not started from inetd, disconnect
766 * from the controlling terminal, and fork. The original process
767 * exits.
768 */
Ben Lindstromc72745a2000-12-02 19:03:54 +0000769 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +1100770#ifdef TIOCNOTTY
771 int fd;
772#endif /* TIOCNOTTY */
773 if (daemon(0, 0) < 0)
774 fatal("daemon() failed: %.200s", strerror(errno));
775
776 /* Disconnect from the controlling tty. */
777#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000778 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +1100779 if (fd >= 0) {
780 (void) ioctl(fd, TIOCNOTTY, NULL);
781 close(fd);
782 }
783#endif /* TIOCNOTTY */
784 }
785 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +0000786 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +1100787
Damien Miller95def091999-11-25 00:26:21 +1100788 /* Initialize the random number generator. */
789 arc4random_stir();
790
791 /* Chdir to the root directory so that the current disk can be
792 unmounted if desired. */
793 chdir("/");
794
Damien Miller95def091999-11-25 00:26:21 +1100795 /* Start listening for a socket, unless started from inetd. */
796 if (inetd_flag) {
797 int s1, s2;
798 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
799 s2 = dup(s1);
800 sock_in = dup(0);
801 sock_out = dup(1);
Damien Miller994cf142000-07-21 10:19:44 +1000802 startup_pipe = -1;
Damien Millereba71ba2000-04-29 23:57:08 +1000803 /*
804 * We intentionally do not close the descriptors 0, 1, and 2
805 * as our code for setting the descriptors won\'t work if
806 * ttyfd happens to be one of those.
807 */
Damien Miller95def091999-11-25 00:26:21 +1100808 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100809 if (options.protocol & SSH_PROTO_1)
810 generate_empheral_server_key();
Damien Miller95def091999-11-25 00:26:21 +1100811 } else {
Damien Miller34132e52000-01-14 15:45:46 +1100812 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
813 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
814 continue;
815 if (num_listen_socks >= MAX_LISTEN_SOCKS)
816 fatal("Too many listen sockets. "
817 "Enlarge MAX_LISTEN_SOCKS");
818 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
819 ntop, sizeof(ntop), strport, sizeof(strport),
820 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
821 error("getnameinfo failed");
822 continue;
823 }
824 /* Create socket for listening. */
825 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
826 if (listen_sock < 0) {
827 /* kernel may not support ipv6 */
828 verbose("socket: %.100s", strerror(errno));
829 continue;
830 }
831 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
832 error("listen_sock O_NONBLOCK: %s", strerror(errno));
833 close(listen_sock);
834 continue;
835 }
836 /*
837 * Set socket options. We try to make the port
838 * reusable and have it close as fast as possible
839 * without waiting in unnecessary wait states on
840 * close.
841 */
842 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
843 (void *) &on, sizeof(on));
844 linger.l_onoff = 1;
845 linger.l_linger = 5;
846 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
847 (void *) &linger, sizeof(linger));
Damien Miller95def091999-11-25 00:26:21 +1100848
Damien Miller34132e52000-01-14 15:45:46 +1100849 debug("Bind to port %s on %s.", strport, ntop);
Damien Miller95def091999-11-25 00:26:21 +1100850
Damien Miller34132e52000-01-14 15:45:46 +1100851 /* Bind the socket to the desired port. */
Damien Miller0a4e27d2001-02-18 12:36:39 +1100852 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
853 if (!ai->ai_next)
854 error("Bind to port %s on %s failed: %.200s.",
855 strport, ntop, strerror(errno));
Damien Miller34132e52000-01-14 15:45:46 +1100856 close(listen_sock);
857 continue;
858 }
859 listen_socks[num_listen_socks] = listen_sock;
860 num_listen_socks++;
Damien Miller95def091999-11-25 00:26:21 +1100861
Damien Miller34132e52000-01-14 15:45:46 +1100862 /* Start listening on the port. */
863 log("Server listening on %s port %s.", ntop, strport);
864 if (listen(listen_sock, 5) < 0)
865 fatal("listen: %.100s", strerror(errno));
866
Damien Miller95def091999-11-25 00:26:21 +1100867 }
Damien Miller34132e52000-01-14 15:45:46 +1100868 freeaddrinfo(options.listen_addrs);
869
870 if (!num_listen_socks)
871 fatal("Cannot bind any address.");
872
Damien Miller95def091999-11-25 00:26:21 +1100873 if (!debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +1100874 /*
Ben Lindstrom7ad97102000-12-06 01:42:49 +0000875 * Record our pid in /var/run/sshd.pid to make it
876 * easier to kill the correct sshd. We don't want to
877 * do this before the bind above because the bind will
Damien Miller5428f641999-11-25 11:54:57 +1100878 * fail if there already is a daemon, and this will
879 * overwrite any old pid in the file.
880 */
Damien Millerbac2d8a2000-09-05 16:13:06 +1100881 f = fopen(options.pid_file, "wb");
Damien Miller95def091999-11-25 00:26:21 +1100882 if (f) {
Ben Lindstrom46c16222000-12-22 01:43:59 +0000883 fprintf(f, "%u\n", (u_int) getpid());
Damien Miller95def091999-11-25 00:26:21 +1100884 fclose(f);
885 }
886 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000887 if (options.protocol & SSH_PROTO_1)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100888 generate_empheral_server_key();
Damien Miller95def091999-11-25 00:26:21 +1100889
Damien Miller95def091999-11-25 00:26:21 +1100890 /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
891 signal(SIGHUP, sighup_handler);
Damien Miller37023962000-07-11 17:31:38 +1000892
Damien Miller95def091999-11-25 00:26:21 +1100893 signal(SIGTERM, sigterm_handler);
894 signal(SIGQUIT, sigterm_handler);
895
896 /* Arrange SIGCHLD to be caught. */
897 signal(SIGCHLD, main_sigchld_handler);
898
Damien Miller34132e52000-01-14 15:45:46 +1100899 /* setup fd set for listen */
Damien Miller37023962000-07-11 17:31:38 +1000900 fdset = NULL;
Damien Miller34132e52000-01-14 15:45:46 +1100901 maxfd = 0;
902 for (i = 0; i < num_listen_socks; i++)
903 if (listen_socks[i] > maxfd)
904 maxfd = listen_socks[i];
Damien Miller37023962000-07-11 17:31:38 +1000905 /* pipes connected to unauthenticated childs */
906 startup_pipes = xmalloc(options.max_startups * sizeof(int));
907 for (i = 0; i < options.max_startups; i++)
908 startup_pipes[i] = -1;
Damien Miller34132e52000-01-14 15:45:46 +1100909
Damien Miller5428f641999-11-25 11:54:57 +1100910 /*
911 * Stay listening for connections until the system crashes or
912 * the daemon is killed with a signal.
913 */
Damien Miller95def091999-11-25 00:26:21 +1100914 for (;;) {
915 if (received_sighup)
916 sighup_restart();
Damien Miller37023962000-07-11 17:31:38 +1000917 if (fdset != NULL)
918 xfree(fdset);
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000919 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
Damien Miller37023962000-07-11 17:31:38 +1000920 fdset = (fd_set *)xmalloc(fdsetsz);
Damien Miller34132e52000-01-14 15:45:46 +1100921 memset(fdset, 0, fdsetsz);
Damien Miller37023962000-07-11 17:31:38 +1000922
Damien Miller34132e52000-01-14 15:45:46 +1100923 for (i = 0; i < num_listen_socks; i++)
924 FD_SET(listen_socks[i], fdset);
Damien Miller37023962000-07-11 17:31:38 +1000925 for (i = 0; i < options.max_startups; i++)
926 if (startup_pipes[i] != -1)
927 FD_SET(startup_pipes[i], fdset);
928
929 /* Wait in select until there is a connection. */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000930 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
931 if (ret < 0 && errno != EINTR)
932 error("select: %.100s", strerror(errno));
933 if (key_used && key_do_regen) {
934 generate_empheral_server_key();
935 key_used = 0;
936 key_do_regen = 0;
Damien Miller34132e52000-01-14 15:45:46 +1100937 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000938 if (ret < 0)
939 continue;
940
Damien Miller37023962000-07-11 17:31:38 +1000941 for (i = 0; i < options.max_startups; i++)
942 if (startup_pipes[i] != -1 &&
943 FD_ISSET(startup_pipes[i], fdset)) {
944 /*
945 * the read end of the pipe is ready
946 * if the child has closed the pipe
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000947 * after successful authentication
Damien Miller37023962000-07-11 17:31:38 +1000948 * or if the child has died
949 */
950 close(startup_pipes[i]);
951 startup_pipes[i] = -1;
952 startups--;
953 }
Damien Miller34132e52000-01-14 15:45:46 +1100954 for (i = 0; i < num_listen_socks; i++) {
955 if (!FD_ISSET(listen_socks[i], fdset))
Damien Miller95def091999-11-25 00:26:21 +1100956 continue;
Damien Miller37023962000-07-11 17:31:38 +1000957 fromlen = sizeof(from);
958 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
959 &fromlen);
960 if (newsock < 0) {
961 if (errno != EINTR && errno != EWOULDBLOCK)
962 error("accept: %.100s", strerror(errno));
963 continue;
964 }
965 if (fcntl(newsock, F_SETFL, 0) < 0) {
966 error("newsock del O_NONBLOCK: %s", strerror(errno));
967 continue;
968 }
Damien Miller942da032000-08-18 13:59:06 +1000969 if (drop_connection(startups) == 1) {
970 debug("drop connection #%d", startups);
Damien Miller37023962000-07-11 17:31:38 +1000971 close(newsock);
972 continue;
973 }
974 if (pipe(startup_p) == -1) {
975 close(newsock);
976 continue;
977 }
978
979 for (j = 0; j < options.max_startups; j++)
980 if (startup_pipes[j] == -1) {
981 startup_pipes[j] = startup_p[0];
982 if (maxfd < startup_p[0])
983 maxfd = startup_p[0];
984 startups++;
985 break;
986 }
Kevin Stevesef4eea92001-02-05 12:42:17 +0000987
Damien Miller5428f641999-11-25 11:54:57 +1100988 /*
Damien Miller37023962000-07-11 17:31:38 +1000989 * Got connection. Fork a child to handle it, unless
990 * we are in debugging mode.
Damien Miller5428f641999-11-25 11:54:57 +1100991 */
Damien Miller37023962000-07-11 17:31:38 +1000992 if (debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +1100993 /*
Damien Miller37023962000-07-11 17:31:38 +1000994 * In debugging mode. Close the listening
995 * socket, and start processing the
996 * connection without forking.
Damien Miller5428f641999-11-25 11:54:57 +1100997 */
Damien Miller37023962000-07-11 17:31:38 +1000998 debug("Server will not fork when running in debugging mode.");
Damien Miller34132e52000-01-14 15:45:46 +1100999 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +11001000 sock_in = newsock;
1001 sock_out = newsock;
Damien Miller4d97ba22000-07-11 18:15:50 +10001002 startup_pipe = -1;
Damien Miller182ee6e2000-07-12 09:45:27 +10001003 pid = getpid();
Damien Miller95def091999-11-25 00:26:21 +11001004 break;
Damien Miller37023962000-07-11 17:31:38 +10001005 } else {
1006 /*
1007 * Normal production daemon. Fork, and have
1008 * the child process the connection. The
1009 * parent continues listening.
1010 */
1011 if ((pid = fork()) == 0) {
1012 /*
1013 * Child. Close the listening and max_startup
1014 * sockets. Start using the accepted socket.
1015 * Reinitialize logging (since our pid has
1016 * changed). We break out of the loop to handle
1017 * the connection.
1018 */
1019 startup_pipe = startup_p[1];
1020 for (j = 0; j < options.max_startups; j++)
1021 if (startup_pipes[j] != -1)
1022 close(startup_pipes[j]);
1023 close_listen_socks();
1024 sock_in = newsock;
1025 sock_out = newsock;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001026 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller37023962000-07-11 17:31:38 +10001027 break;
1028 }
Damien Miller95def091999-11-25 00:26:21 +11001029 }
Damien Miller37023962000-07-11 17:31:38 +10001030
1031 /* Parent. Stay in the loop. */
1032 if (pid < 0)
1033 error("fork: %.100s", strerror(errno));
1034 else
1035 debug("Forked child %d.", pid);
1036
1037 close(startup_p[1]);
1038
1039 /* Mark that the key has been used (it was "given" to the child). */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001040 if ((options.protocol & SSH_PROTO_1) &&
1041 key_used == 0) {
1042 /* Schedule server key regeneration alarm. */
1043 signal(SIGALRM, key_regeneration_alarm);
1044 alarm(options.key_regeneration_time);
1045 key_used = 1;
1046 }
Damien Miller37023962000-07-11 17:31:38 +10001047
1048 arc4random_stir();
1049
1050 /* Close the new socket (the child is now taking care of it). */
1051 close(newsock);
Damien Miller95def091999-11-25 00:26:21 +11001052 }
Damien Miller34132e52000-01-14 15:45:46 +11001053 /* child process check (or debug mode) */
1054 if (num_listen_socks < 0)
1055 break;
Damien Miller95def091999-11-25 00:26:21 +11001056 }
1057 }
1058
1059 /* This is the child processing a new connection. */
1060
Damien Miller5428f641999-11-25 11:54:57 +11001061 /*
1062 * Disable the key regeneration alarm. We will not regenerate the
1063 * key since we are no longer in a position to give it to anyone. We
1064 * will not restart on SIGHUP since it no longer makes sense.
1065 */
Damien Miller95def091999-11-25 00:26:21 +11001066 alarm(0);
1067 signal(SIGALRM, SIG_DFL);
1068 signal(SIGHUP, SIG_DFL);
1069 signal(SIGTERM, SIG_DFL);
1070 signal(SIGQUIT, SIG_DFL);
1071 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001072 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001073
Damien Miller5428f641999-11-25 11:54:57 +11001074 /*
1075 * Set socket options for the connection. We want the socket to
1076 * close as fast as possible without waiting for anything. If the
1077 * connection is not a socket, these will do nothing.
1078 */
1079 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
Damien Miller95def091999-11-25 00:26:21 +11001080 linger.l_onoff = 1;
1081 linger.l_linger = 5;
1082 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
1083
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001084 /* Set keepalives if requested. */
1085 if (options.keepalives &&
1086 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
1087 sizeof(on)) < 0)
1088 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1089
Damien Miller5428f641999-11-25 11:54:57 +11001090 /*
1091 * Register our connection. This turns encryption off because we do
1092 * not have a key.
1093 */
Damien Miller95def091999-11-25 00:26:21 +11001094 packet_set_connection(sock_in, sock_out);
1095
1096 remote_port = get_remote_port();
1097 remote_ip = get_remote_ipaddr();
1098
1099 /* Check whether logins are denied from this host. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001100#ifdef LIBWRAP
Damien Miller34132e52000-01-14 15:45:46 +11001101 /* XXX LIBWRAP noes not know about IPv6 */
Damien Miller95def091999-11-25 00:26:21 +11001102 {
1103 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001104
Kevin Stevesec84dc12000-12-13 17:45:15 +00001105 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, NULL);
Damien Miller95def091999-11-25 00:26:21 +11001106 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001107
Damien Miller95def091999-11-25 00:26:21 +11001108 if (!hosts_access(&req)) {
1109 close(sock_in);
1110 close(sock_out);
1111 refuse(&req);
1112 }
Damien Miller34132e52000-01-14 15:45:46 +11001113/*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
Damien Miller95def091999-11-25 00:26:21 +11001114 }
Damien Miller34132e52000-01-14 15:45:46 +11001115#endif /* LIBWRAP */
Damien Miller95def091999-11-25 00:26:21 +11001116 /* Log the connection. */
1117 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001118
Damien Miller5428f641999-11-25 11:54:57 +11001119 /*
1120 * We don\'t want to listen forever unless the other side
1121 * successfully authenticates itself. So we set up an alarm which is
1122 * cleared after successful authentication. A limit of zero
1123 * indicates no limit. Note that we don\'t set the alarm in debugging
1124 * mode; it is just annoying to have the server exit just when you
1125 * are about to discover the bug.
1126 */
Damien Miller95def091999-11-25 00:26:21 +11001127 signal(SIGALRM, grace_alarm_handler);
1128 if (!debug_flag)
1129 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001130
Damien Millerb38eff82000-04-01 11:09:21 +10001131 sshd_exchange_identification(sock_in, sock_out);
Damien Miller5428f641999-11-25 11:54:57 +11001132 /*
Kevin Stevesfcec7f82000-12-15 19:55:48 +00001133 * Check that the connection comes from a privileged port.
1134 * Rhosts-Authentication only makes sense from priviledged
Damien Miller5428f641999-11-25 11:54:57 +11001135 * programs. Of course, if the intruder has root access on his local
1136 * machine, he can connect from any port. So do not use these
1137 * authentication methods from machines that you do not trust.
1138 */
Damien Miller95def091999-11-25 00:26:21 +11001139 if (remote_port >= IPPORT_RESERVED ||
1140 remote_port < IPPORT_RESERVED / 2) {
Kevin Stevesfcec7f82000-12-15 19:55:48 +00001141 debug("Rhosts Authentication disabled, "
Damien Miller0bc1bd82000-11-13 22:57:25 +11001142 "originating port not trusted.");
Damien Miller95def091999-11-25 00:26:21 +11001143 options.rhosts_authentication = 0;
Damien Miller95def091999-11-25 00:26:21 +11001144 }
Damien Miller34132e52000-01-14 15:45:46 +11001145#ifdef KRB4
1146 if (!packet_connection_is_ipv4() &&
1147 options.kerberos_authentication) {
1148 debug("Kerberos Authentication disabled, only available for IPv4.");
1149 options.kerberos_authentication = 0;
1150 }
1151#endif /* KRB4 */
Ben Lindstromf79aeff2001-02-10 21:27:11 +00001152#ifdef AFS
1153 /* If machine has AFS, set process authentication group. */
1154 if (k_hasafs()) {
1155 k_setpag();
1156 k_unlog();
1157 }
1158#endif /* AFS */
Damien Miller34132e52000-01-14 15:45:46 +11001159
Damien Miller95def091999-11-25 00:26:21 +11001160 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001161
Damien Miller396691a2000-01-20 22:44:08 +11001162 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001163 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001164 if (compat20) {
1165 do_ssh2_kex();
1166 do_authentication2();
1167 } else {
1168 do_ssh1_kex();
1169 do_authentication();
1170 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001171
1172#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +11001173 /* Cleanup user's ticket cache file. */
1174 if (options.kerberos_ticket_cleanup)
1175 (void) dest_tkt();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001176#endif /* KRB4 */
1177
Damien Miller95def091999-11-25 00:26:21 +11001178 /* The connection has been terminated. */
1179 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001180
Damien Millerbeb4ba51999-12-28 15:09:35 +11001181#ifdef USE_PAM
Damien Millere72b7af1999-12-30 15:08:44 +11001182 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001183#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001184
Damien Miller95def091999-11-25 00:26:21 +11001185 packet_close();
1186 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001187}
1188
Damien Miller95def091999-11-25 00:26:21 +11001189/*
Damien Miller396691a2000-01-20 22:44:08 +11001190 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001191 */
Damien Miller2ccf6611999-11-15 15:25:10 +11001192void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001193do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001194{
Damien Miller95def091999-11-25 00:26:21 +11001195 int i, len;
Damien Miller396691a2000-01-20 22:44:08 +11001196 int plen, slen;
Damien Miller7650bc62001-01-30 09:27:26 +11001197 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001198 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001199 u_char session_key[SSH_SESSION_KEY_LENGTH];
1200 u_char cookie[8];
1201 u_int cipher_type, auth_mask, protocol_flags;
Damien Miller95def091999-11-25 00:26:21 +11001202 u_int32_t rand = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001203
Damien Miller5428f641999-11-25 11:54:57 +11001204 /*
1205 * Generate check bytes that the client must send back in the user
1206 * packet in order for it to be accepted; this is used to defy ip
1207 * spoofing attacks. Note that this only works against somebody
1208 * doing IP spoofing from a remote machine; any machine on the local
1209 * network can still see outgoing packets and catch the random
1210 * cookie. This only affects rhosts authentication, and this is one
1211 * of the reasons why it is inherently insecure.
1212 */
Damien Miller95def091999-11-25 00:26:21 +11001213 for (i = 0; i < 8; i++) {
1214 if (i % 4 == 0)
1215 rand = arc4random();
Damien Miller396691a2000-01-20 22:44:08 +11001216 cookie[i] = rand & 0xff;
Damien Miller95def091999-11-25 00:26:21 +11001217 rand >>= 8;
1218 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001219
Damien Miller5428f641999-11-25 11:54:57 +11001220 /*
1221 * Send our public key. We include in the packet 64 bits of random
1222 * data that must be matched in the reply in order to prevent IP
1223 * spoofing.
1224 */
Damien Miller95def091999-11-25 00:26:21 +11001225 packet_start(SSH_SMSG_PUBLIC_KEY);
1226 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001227 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001228
Damien Miller95def091999-11-25 00:26:21 +11001229 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001230 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1231 packet_put_bignum(sensitive_data.server_key->rsa->e);
1232 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001233
Damien Miller95def091999-11-25 00:26:21 +11001234 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001235 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1236 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1237 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001238
Damien Miller95def091999-11-25 00:26:21 +11001239 /* Put protocol flags. */
1240 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001241
Damien Miller95def091999-11-25 00:26:21 +11001242 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001243 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001244
1245 /* Declare supported authentication types. */
1246 auth_mask = 0;
1247 if (options.rhosts_authentication)
1248 auth_mask |= 1 << SSH_AUTH_RHOSTS;
1249 if (options.rhosts_rsa_authentication)
1250 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1251 if (options.rsa_authentication)
1252 auth_mask |= 1 << SSH_AUTH_RSA;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001253#ifdef KRB4
Damien Miller95def091999-11-25 00:26:21 +11001254 if (options.kerberos_authentication)
1255 auth_mask |= 1 << SSH_AUTH_KERBEROS;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001256#endif
1257#ifdef AFS
Damien Miller95def091999-11-25 00:26:21 +11001258 if (options.kerberos_tgt_passing)
1259 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1260 if (options.afs_token_passing)
1261 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001262#endif
Ben Lindstrom95fb2dd2001-01-23 03:12:10 +00001263 if (options.challenge_reponse_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001264 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001265 if (options.password_authentication)
1266 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1267 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001268
Damien Miller95def091999-11-25 00:26:21 +11001269 /* Send the packet and wait for it to be sent. */
1270 packet_send();
1271 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001272
Damien Miller0bc1bd82000-11-13 22:57:25 +11001273 debug("Sent %d bit server key and %d bit host key.",
1274 BN_num_bits(sensitive_data.server_key->rsa->n),
1275 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001276
Damien Miller95def091999-11-25 00:26:21 +11001277 /* Read clients reply (cipher type and session key). */
1278 packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001279
Damien Miller50945fa1999-12-09 10:31:37 +11001280 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11001281 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001282
Damien Miller874d77b2000-10-14 16:23:11 +11001283 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11001284 packet_disconnect("Warning: client selects unsupported cipher.");
1285
Damien Miller95def091999-11-25 00:26:21 +11001286 /* Get check bytes from the packet. These must match those we
1287 sent earlier with the public key packet. */
1288 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001289 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11001290 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001291
Damien Miller95def091999-11-25 00:26:21 +11001292 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001293
Damien Miller95def091999-11-25 00:26:21 +11001294 /* Get the encrypted integer. */
1295 session_key_int = BN_new();
1296 packet_get_bignum(session_key_int, &slen);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001297
Damien Miller95def091999-11-25 00:26:21 +11001298 protocol_flags = packet_get_int();
1299 packet_set_protocol_flags(protocol_flags);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001300
Damien Miller95def091999-11-25 00:26:21 +11001301 packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001302
Damien Miller5428f641999-11-25 11:54:57 +11001303 /*
1304 * Decrypt it using our private server key and private host key (key
1305 * with larger modulus first).
1306 */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001307 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
Damien Miller7650bc62001-01-30 09:27:26 +11001308 /* Server key has bigger modulus. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001309 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1310 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1311 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1312 get_remote_ipaddr(),
1313 BN_num_bits(sensitive_data.server_key->rsa->n),
1314 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1315 SSH_KEY_BITS_RESERVED);
Damien Miller95def091999-11-25 00:26:21 +11001316 }
Damien Miller7650bc62001-01-30 09:27:26 +11001317 if (rsa_private_decrypt(session_key_int, session_key_int,
1318 sensitive_data.server_key->rsa) <= 0)
1319 rsafail++;
1320 if (rsa_private_decrypt(session_key_int, session_key_int,
1321 sensitive_data.ssh1_host_key->rsa) <= 0)
1322 rsafail++;
Damien Miller95def091999-11-25 00:26:21 +11001323 } else {
1324 /* Host key has bigger modulus (or they are equal). */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001325 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1326 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1327 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1328 get_remote_ipaddr(),
1329 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1330 BN_num_bits(sensitive_data.server_key->rsa->n),
1331 SSH_KEY_BITS_RESERVED);
Damien Miller95def091999-11-25 00:26:21 +11001332 }
Damien Miller7650bc62001-01-30 09:27:26 +11001333 if (rsa_private_decrypt(session_key_int, session_key_int,
1334 sensitive_data.ssh1_host_key->rsa) < 0)
1335 rsafail++;
1336 if (rsa_private_decrypt(session_key_int, session_key_int,
1337 sensitive_data.server_key->rsa) < 0)
1338 rsafail++;
Damien Miller95def091999-11-25 00:26:21 +11001339 }
Damien Miller356a0b01999-11-08 15:30:59 +11001340
Damien Miller396691a2000-01-20 22:44:08 +11001341 compute_session_id(session_id, cookie,
Damien Miller0bc1bd82000-11-13 22:57:25 +11001342 sensitive_data.ssh1_host_key->rsa->n,
1343 sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001344
Damien Miller396691a2000-01-20 22:44:08 +11001345 /* Destroy the private and public keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +10001346 destroy_sensitive_data();
Damien Miller396691a2000-01-20 22:44:08 +11001347
Damien Miller5428f641999-11-25 11:54:57 +11001348 /*
1349 * Extract session key from the decrypted integer. The key is in the
1350 * least significant 256 bits of the integer; the first byte of the
1351 * key is in the highest bits.
1352 */
Damien Miller7650bc62001-01-30 09:27:26 +11001353 if (!rsafail) {
1354 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1355 len = BN_num_bytes(session_key_int);
1356 if (len < 0 || len > sizeof(session_key)) {
1357 error("do_connection: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001358 "session_key_int %d > sizeof(session_key) %lu",
1359 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11001360 rsafail++;
1361 } else {
1362 memset(session_key, 0, sizeof(session_key));
1363 BN_bn2bin(session_key_int,
1364 session_key + sizeof(session_key) - len);
1365 }
1366 }
1367 if (rsafail) {
1368 log("do_connection: generating a fake encryption key");
1369 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
1370 if (i % 4 == 0)
1371 rand = arc4random();
1372 session_key[i] = rand & 0xff;
1373 rand >>= 8;
1374 }
1375 }
Damien Miller396691a2000-01-20 22:44:08 +11001376 /* Destroy the decrypted integer. It is no longer needed. */
1377 BN_clear_free(session_key_int);
1378
Damien Miller95def091999-11-25 00:26:21 +11001379 /* Xor the first 16 bytes of the session key with the session id. */
1380 for (i = 0; i < 16; i++)
1381 session_key[i] ^= session_id[i];
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001382
Damien Miller95def091999-11-25 00:26:21 +11001383 /* Set the session key. From this on all communications will be encrypted. */
1384 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001385
Damien Miller95def091999-11-25 00:26:21 +11001386 /* Destroy our copy of the session key. It is no longer needed. */
1387 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001388
Damien Miller95def091999-11-25 00:26:21 +11001389 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001390
Damien Miller95def091999-11-25 00:26:21 +11001391 /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1392 packet_start(SSH_SMSG_SUCCESS);
1393 packet_send();
1394 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001395}
Damien Millerefb4afe2000-04-12 18:45:05 +10001396
1397/*
1398 * SSH2 key exchange: diffie-hellman-group1-sha1
1399 */
1400void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001401do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10001402{
1403 Buffer *server_kexinit;
1404 Buffer *client_kexinit;
Damien Miller874d77b2000-10-14 16:23:11 +11001405 int payload_len;
Damien Millerefb4afe2000-04-12 18:45:05 +10001406 int i;
Damien Millerefb4afe2000-04-12 18:45:05 +10001407 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10001408 char *cprop[PROPOSAL_MAX];
Damien Millerefb4afe2000-04-12 18:45:05 +10001409
1410/* KEXINIT */
1411
Damien Miller78928792000-04-12 20:17:38 +10001412 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10001413 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10001414 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1415 }
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00001416 if (options.macs != NULL) {
1417 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1418 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1419 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001420 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1421
Damien Millerb1715dc2000-05-30 13:44:51 +10001422 server_kexinit = kex_init(myproposal);
Damien Millerefb4afe2000-04-12 18:45:05 +10001423 client_kexinit = xmalloc(sizeof(*client_kexinit));
1424 buffer_init(client_kexinit);
Damien Millerefb4afe2000-04-12 18:45:05 +10001425
Damien Millerb1715dc2000-05-30 13:44:51 +10001426 /* algorithm negotiation */
1427 kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
1428 kex = kex_choose_conf(cprop, myproposal, 1);
1429 for (i = 0; i < PROPOSAL_MAX; i++)
1430 xfree(cprop[i]);
Damien Millerefb4afe2000-04-12 18:45:05 +10001431
Damien Miller874d77b2000-10-14 16:23:11 +11001432 switch (kex->kex_type) {
1433 case DH_GRP1_SHA1:
1434 ssh_dh1_server(kex, client_kexinit, server_kexinit);
1435 break;
1436 case DH_GEX_SHA1:
1437 ssh_dhgex_server(kex, client_kexinit, server_kexinit);
1438 break;
1439 default:
1440 fatal("Unsupported key exchange %d", kex->kex_type);
1441 }
Damien Millerefb4afe2000-04-12 18:45:05 +10001442
Damien Miller874d77b2000-10-14 16:23:11 +11001443 debug("send SSH2_MSG_NEWKEYS.");
1444 packet_start(SSH2_MSG_NEWKEYS);
1445 packet_send();
1446 packet_write_wait();
1447 debug("done: send SSH2_MSG_NEWKEYS.");
1448
1449 debug("Wait SSH2_MSG_NEWKEYS.");
1450 packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
1451 debug("GOT SSH2_MSG_NEWKEYS.");
1452
1453#ifdef DEBUG_KEXDH
1454 /* send 1st encrypted/maced/compressed message */
1455 packet_start(SSH2_MSG_IGNORE);
1456 packet_put_cstring("markus");
1457 packet_send();
1458 packet_write_wait();
1459#endif
1460
1461 debug("done: KEX2.");
1462}
1463
1464/*
1465 * SSH2 key exchange
1466 */
1467
1468/* diffie-hellman-group1-sha1 */
1469
1470void
1471ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
1472{
1473#ifdef DEBUG_KEXDH
1474 int i;
1475#endif
1476 int payload_len, dlen;
1477 int slen;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001478 u_char *signature = NULL;
1479 u_char *server_host_key_blob = NULL;
1480 u_int sbloblen;
1481 u_int klen, kout;
1482 u_char *kbuf;
1483 u_char *hash;
Damien Miller874d77b2000-10-14 16:23:11 +11001484 BIGNUM *shared_secret = 0;
1485 DH *dh;
1486 BIGNUM *dh_client_pub = 0;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001487 Key *hostkey;
1488
1489 hostkey = get_hostkey_by_type(kex->hostkey_type);
1490 if (hostkey == NULL)
1491 fatal("Unsupported hostkey type %d", kex->hostkey_type);
Damien Miller874d77b2000-10-14 16:23:11 +11001492
1493/* KEXDH */
Kevin Steves6b875862000-12-15 23:31:01 +00001494 /* generate DH key */
1495 dh = dh_new_group1(); /* XXX depends on 'kex' */
1496 dh_gen_key(dh);
1497
Damien Millerefb4afe2000-04-12 18:45:05 +10001498 debug("Wait SSH2_MSG_KEXDH_INIT.");
1499 packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
1500
1501 /* key, cert */
1502 dh_client_pub = BN_new();
1503 if (dh_client_pub == NULL)
1504 fatal("dh_client_pub == NULL");
1505 packet_get_bignum2(dh_client_pub, &dlen);
1506
1507#ifdef DEBUG_KEXDH
1508 fprintf(stderr, "\ndh_client_pub= ");
Damien Miller62cee002000-09-23 17:15:56 +11001509 BN_print_fp(stderr, dh_client_pub);
Damien Millerefb4afe2000-04-12 18:45:05 +10001510 fprintf(stderr, "\n");
1511 debug("bits %d", BN_num_bits(dh_client_pub));
1512#endif
1513
Damien Millerefb4afe2000-04-12 18:45:05 +10001514#ifdef DEBUG_KEXDH
1515 fprintf(stderr, "\np= ");
Damien Miller62cee002000-09-23 17:15:56 +11001516 BN_print_fp(stderr, dh->p);
Damien Millerefb4afe2000-04-12 18:45:05 +10001517 fprintf(stderr, "\ng= ");
Damien Miller62cee002000-09-23 17:15:56 +11001518 bn_print(dh->g);
Damien Millerefb4afe2000-04-12 18:45:05 +10001519 fprintf(stderr, "\npub= ");
Damien Miller62cee002000-09-23 17:15:56 +11001520 BN_print_fp(stderr, dh->pub_key);
Damien Millerefb4afe2000-04-12 18:45:05 +10001521 fprintf(stderr, "\n");
Kevin Stevesef4eea92001-02-05 12:42:17 +00001522 DHparams_print_fp(stderr, dh);
Damien Millerefb4afe2000-04-12 18:45:05 +10001523#endif
Damien Miller78928792000-04-12 20:17:38 +10001524 if (!dh_pub_is_valid(dh, dh_client_pub))
1525 packet_disconnect("bad client public DH value");
Damien Millerefb4afe2000-04-12 18:45:05 +10001526
1527 klen = DH_size(dh);
1528 kbuf = xmalloc(klen);
1529 kout = DH_compute_key(kbuf, dh_client_pub, dh);
1530
1531#ifdef DEBUG_KEXDH
1532 debug("shared secret: len %d/%d", klen, kout);
1533 fprintf(stderr, "shared secret == ");
1534 for (i = 0; i< kout; i++)
1535 fprintf(stderr, "%02x", (kbuf[i])&0xff);
1536 fprintf(stderr, "\n");
1537#endif
1538 shared_secret = BN_new();
1539
1540 BN_bin2bn(kbuf, kout, shared_secret);
1541 memset(kbuf, 0, klen);
1542 xfree(kbuf);
1543
Damien Millereba71ba2000-04-29 23:57:08 +10001544 /* XXX precompute? */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001545 key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
Damien Millerefb4afe2000-04-12 18:45:05 +10001546
1547 /* calc H */ /* XXX depends on 'kex' */
1548 hash = kex_hash(
1549 client_version_string,
1550 server_version_string,
1551 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
1552 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
1553 (char *)server_host_key_blob, sbloblen,
1554 dh_client_pub,
1555 dh->pub_key,
1556 shared_secret
1557 );
1558 buffer_free(client_kexinit);
1559 buffer_free(server_kexinit);
1560 xfree(client_kexinit);
1561 xfree(server_kexinit);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001562 BN_free(dh_client_pub);
Damien Millerefb4afe2000-04-12 18:45:05 +10001563#ifdef DEBUG_KEXDH
Damien Miller4af51302000-04-16 11:18:38 +10001564 fprintf(stderr, "hash == ");
1565 for (i = 0; i< 20; i++)
1566 fprintf(stderr, "%02x", (hash[i])&0xff);
1567 fprintf(stderr, "\n");
Damien Millerefb4afe2000-04-12 18:45:05 +10001568#endif
Damien Millereba71ba2000-04-29 23:57:08 +10001569 /* save session id := H */
1570 /* XXX hashlen depends on KEX */
1571 session_id2_len = 20;
1572 session_id2 = xmalloc(session_id2_len);
1573 memcpy(session_id2, hash, session_id2_len);
1574
Damien Millerefb4afe2000-04-12 18:45:05 +10001575 /* sign H */
Damien Millereba71ba2000-04-29 23:57:08 +10001576 /* XXX hashlen depends on KEX */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001577 key_sign(hostkey, &signature, &slen, hash, 20);
Damien Millereba71ba2000-04-29 23:57:08 +10001578
1579 destroy_sensitive_data();
Damien Millerefb4afe2000-04-12 18:45:05 +10001580
1581 /* send server hostkey, DH pubkey 'f' and singed H */
1582 packet_start(SSH2_MSG_KEXDH_REPLY);
1583 packet_put_string((char *)server_host_key_blob, sbloblen);
Damien Millere247cc42000-05-07 12:03:14 +10001584 packet_put_bignum2(dh->pub_key); /* f */
Damien Millerefb4afe2000-04-12 18:45:05 +10001585 packet_put_string((char *)signature, slen);
1586 packet_send();
Damien Miller8bb73be2000-04-19 16:26:12 +10001587 xfree(signature);
Damien Millereba71ba2000-04-29 23:57:08 +10001588 xfree(server_host_key_blob);
Damien Millerefb4afe2000-04-12 18:45:05 +10001589 packet_write_wait();
1590
1591 kex_derive_keys(kex, hash, shared_secret);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001592 BN_clear_free(shared_secret);
Damien Millerefb4afe2000-04-12 18:45:05 +10001593 packet_set_kex(kex);
1594
1595 /* have keys, free DH */
1596 DH_free(dh);
Damien Miller874d77b2000-10-14 16:23:11 +11001597}
Damien Millerefb4afe2000-04-12 18:45:05 +10001598
Damien Miller874d77b2000-10-14 16:23:11 +11001599/* diffie-hellman-group-exchange-sha1 */
1600
1601void
1602ssh_dhgex_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
1603{
1604#ifdef DEBUG_KEXDH
1605 int i;
1606#endif
1607 int payload_len, dlen;
1608 int slen, nbits;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001609 u_char *signature = NULL;
1610 u_char *server_host_key_blob = NULL;
1611 u_int sbloblen;
1612 u_int klen, kout;
1613 u_char *kbuf;
1614 u_char *hash;
Damien Miller874d77b2000-10-14 16:23:11 +11001615 BIGNUM *shared_secret = 0;
1616 DH *dh;
1617 BIGNUM *dh_client_pub = 0;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001618 Key *hostkey;
1619
1620 hostkey = get_hostkey_by_type(kex->hostkey_type);
1621 if (hostkey == NULL)
1622 fatal("Unsupported hostkey type %d", kex->hostkey_type);
Damien Miller874d77b2000-10-14 16:23:11 +11001623
1624/* KEXDHGEX */
1625 debug("Wait SSH2_MSG_KEX_DH_GEX_REQUEST.");
1626 packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_REQUEST);
1627 nbits = packet_get_int();
1628 dh = choose_dh(nbits);
1629
1630 debug("Sending SSH2_MSG_KEX_DH_GEX_GROUP.");
1631 packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
1632 packet_put_bignum2(dh->p);
1633 packet_put_bignum2(dh->g);
Damien Millerefb4afe2000-04-12 18:45:05 +10001634 packet_send();
1635 packet_write_wait();
Damien Millerefb4afe2000-04-12 18:45:05 +10001636
Kevin Steves6b875862000-12-15 23:31:01 +00001637 /* Compute our exchange value in parallel with the client */
1638
1639 dh_gen_key(dh);
1640
Damien Miller874d77b2000-10-14 16:23:11 +11001641 debug("Wait SSH2_MSG_KEX_DH_GEX_INIT.");
1642 packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_INIT);
1643
1644 /* key, cert */
1645 dh_client_pub = BN_new();
1646 if (dh_client_pub == NULL)
1647 fatal("dh_client_pub == NULL");
1648 packet_get_bignum2(dh_client_pub, &dlen);
Damien Millerefb4afe2000-04-12 18:45:05 +10001649
Damien Miller78928792000-04-12 20:17:38 +10001650#ifdef DEBUG_KEXDH
Damien Miller874d77b2000-10-14 16:23:11 +11001651 fprintf(stderr, "\ndh_client_pub= ");
1652 BN_print_fp(stderr, dh_client_pub);
1653 fprintf(stderr, "\n");
1654 debug("bits %d", BN_num_bits(dh_client_pub));
Damien Miller78928792000-04-12 20:17:38 +10001655#endif
Damien Miller874d77b2000-10-14 16:23:11 +11001656
1657#ifdef DEBUG_KEXDH
1658 fprintf(stderr, "\np= ");
1659 BN_print_fp(stderr, dh->p);
1660 fprintf(stderr, "\ng= ");
1661 bn_print(dh->g);
1662 fprintf(stderr, "\npub= ");
1663 BN_print_fp(stderr, dh->pub_key);
1664 fprintf(stderr, "\n");
Kevin Stevesef4eea92001-02-05 12:42:17 +00001665 DHparams_print_fp(stderr, dh);
Damien Miller874d77b2000-10-14 16:23:11 +11001666#endif
1667 if (!dh_pub_is_valid(dh, dh_client_pub))
1668 packet_disconnect("bad client public DH value");
1669
1670 klen = DH_size(dh);
1671 kbuf = xmalloc(klen);
1672 kout = DH_compute_key(kbuf, dh_client_pub, dh);
1673
1674#ifdef DEBUG_KEXDH
1675 debug("shared secret: len %d/%d", klen, kout);
1676 fprintf(stderr, "shared secret == ");
1677 for (i = 0; i< kout; i++)
1678 fprintf(stderr, "%02x", (kbuf[i])&0xff);
1679 fprintf(stderr, "\n");
1680#endif
1681 shared_secret = BN_new();
1682
1683 BN_bin2bn(kbuf, kout, shared_secret);
1684 memset(kbuf, 0, klen);
1685 xfree(kbuf);
1686
1687 /* XXX precompute? */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001688 key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
Damien Miller874d77b2000-10-14 16:23:11 +11001689
1690 /* calc H */ /* XXX depends on 'kex' */
1691 hash = kex_hash_gex(
1692 client_version_string,
1693 server_version_string,
1694 buffer_ptr(client_kexinit), buffer_len(client_kexinit),
1695 buffer_ptr(server_kexinit), buffer_len(server_kexinit),
1696 (char *)server_host_key_blob, sbloblen,
1697 nbits, dh->p, dh->g,
1698 dh_client_pub,
1699 dh->pub_key,
1700 shared_secret
1701 );
1702 buffer_free(client_kexinit);
1703 buffer_free(server_kexinit);
1704 xfree(client_kexinit);
1705 xfree(server_kexinit);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001706 BN_free(dh_client_pub);
Damien Miller874d77b2000-10-14 16:23:11 +11001707#ifdef DEBUG_KEXDH
1708 fprintf(stderr, "hash == ");
1709 for (i = 0; i< 20; i++)
1710 fprintf(stderr, "%02x", (hash[i])&0xff);
1711 fprintf(stderr, "\n");
1712#endif
1713 /* save session id := H */
1714 /* XXX hashlen depends on KEX */
1715 session_id2_len = 20;
1716 session_id2 = xmalloc(session_id2_len);
1717 memcpy(session_id2, hash, session_id2_len);
1718
1719 /* sign H */
1720 /* XXX hashlen depends on KEX */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001721 key_sign(hostkey, &signature, &slen, hash, 20);
Damien Miller874d77b2000-10-14 16:23:11 +11001722
1723 destroy_sensitive_data();
1724
1725 /* send server hostkey, DH pubkey 'f' and singed H */
1726 packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
1727 packet_put_string((char *)server_host_key_blob, sbloblen);
1728 packet_put_bignum2(dh->pub_key); /* f */
1729 packet_put_string((char *)signature, slen);
1730 packet_send();
1731 xfree(signature);
1732 xfree(server_host_key_blob);
1733 packet_write_wait();
1734
1735 kex_derive_keys(kex, hash, shared_secret);
Ben Lindstromb1985f72001-01-23 00:19:15 +00001736 BN_clear_free(shared_secret);
Damien Miller874d77b2000-10-14 16:23:11 +11001737 packet_set_kex(kex);
1738
1739 /* have keys, free DH */
1740 DH_free(dh);
Damien Millerefb4afe2000-04-12 18:45:05 +10001741}