Annotation of src/usr.bin/ssh/sshd.c, Revision 1.132.2.1
1.86 markus 1: /*
1.65 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.126 deraadt 5: * This program is the ssh daemon. It listens for connections from clients,
6: * and performs authentication, executes use commands or shell, and forwards
1.65 deraadt 7: * information to/from the application to the user client over an encrypted
1.126 deraadt 8: * connection. This can also handle forwarding of X11, TCP/IP, and
9: * authentication agent connections.
1.98 markus 10: *
1.126 deraadt 11: * As far as I am concerned, the code I have written for this software
12: * can be used freely for any purpose. Any derived versions of this
13: * software must be clearly marked as such, and if the derived work is
14: * incompatible with the protocol description in the RFC file, it must be
15: * called by a name other than "ssh" or "Secure Shell".
16: *
17: * SSH2 implementation:
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.
1.65 deraadt 40: */
1.1 deraadt 41:
42: #include "includes.h"
1.132.2.1! jason 43: RCSID("$OpenBSD: sshd.c,v 1.167 2001/02/12 23:26:20 markus Exp $");
1.1 deraadt 44:
1.132.2.1! jason 45: #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"
1.1 deraadt 52: #include "xmalloc.h"
53: #include "rsa.h"
54: #include "pty.h"
55: #include "packet.h"
56: #include "mpaux.h"
1.132.2.1! jason 57: #include "log.h"
1.1 deraadt 58: #include "servconf.h"
59: #include "uidswap.h"
1.33 markus 60: #include "compat.h"
1.96 markus 61: #include "buffer.h"
1.132.2.1! jason 62: #include "cipher.h"
1.98 markus 63: #include "kex.h"
1.96 markus 64: #include "key.h"
1.129 provos 65: #include "dh.h"
1.98 markus 66: #include "myproposal.h"
1.108 markus 67: #include "authfile.h"
1.132.2.1! jason 68: #include "pathnames.h"
! 69: #include "atomicio.h"
! 70: #include "canohost.h"
! 71: #include "auth.h"
! 72: #include "misc.h"
1.1 deraadt 73:
74: #ifdef LIBWRAP
75: #include <tcpd.h>
76: #include <syslog.h>
77: int allow_severity = LOG_INFO;
78: int deny_severity = LOG_WARNING;
79: #endif /* LIBWRAP */
80:
81: #ifndef O_NOCTTY
82: #define O_NOCTTY 0
83: #endif
84:
1.132.2.1! jason 85: extern char *__progname;
! 86:
1.1 deraadt 87: /* Server configuration options. */
88: ServerOptions options;
89:
90: /* Name of the server configuration file. */
1.132.2.1! jason 91: char *config_file_name = _PATH_SERVER_CONFIG_FILE;
1.1 deraadt 92:
1.105 markus 93: /*
1.75 markus 94: * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
95: * Default value is AF_UNSPEC means both IPv4 and IPv6.
96: */
97: int IPv4or6 = AF_UNSPEC;
98:
1.65 deraadt 99: /*
100: * Debug mode flag. This can be set on the command line. If debug
101: * mode is enabled, extra debugging output will be sent to the system
102: * log, the daemon will not go to background, and will exit after processing
103: * the first connection.
104: */
1.1 deraadt 105: int debug_flag = 0;
106:
107: /* Flag indicating that the daemon is being started from inetd. */
108: int inetd_flag = 0;
109:
1.132.2.1! jason 110: /* Flag indicating that sshd should not detach and become a daemon. */
! 111: int no_daemon_flag = 0;
! 112:
1.47 markus 113: /* debug goes to stderr unless inetd_flag is set */
114: int log_stderr = 0;
115:
1.1 deraadt 116: /* Saved arguments to main(). */
117: char **saved_argv;
118:
1.66 markus 119: /*
1.75 markus 120: * The sockets that the server is listening; this is used in the SIGHUP
121: * signal handler.
1.66 markus 122: */
1.75 markus 123: #define MAX_LISTEN_SOCKS 16
124: int listen_socks[MAX_LISTEN_SOCKS];
125: int num_listen_socks = 0;
1.1 deraadt 126:
1.66 markus 127: /*
128: * the client's version string, passed by sshd2 in compat mode. if != NULL,
129: * sshd will skip the version-number exchange
130: */
1.61 markus 131: char *client_version_string = NULL;
1.96 markus 132: char *server_version_string = NULL;
1.1 deraadt 133:
1.66 markus 134: /*
135: * Any really sensitive data in the application is contained in this
136: * structure. The idea is that this structure could be locked into memory so
137: * that the pages do not get written into swap. However, there are some
138: * problems. The private key contains BIGNUMs, and we do not (in principle)
139: * have access to the internals of them, and locking just the structure is
140: * not very useful. Currently, memory locking is not implemented.
141: */
1.64 markus 142: struct {
1.132.2.1! jason 143: Key *server_key; /* empheral server key */
! 144: Key *ssh1_host_key; /* ssh1 host key */
! 145: Key **host_keys; /* all private host keys */
! 146: int have_ssh1_key;
! 147: int have_ssh2_key;
1.1 deraadt 148: } sensitive_data;
149:
1.66 markus 150: /*
1.132.2.1! jason 151: * Flag indicating whether the RSA server key needs to be regenerated.
! 152: * Is set in the SIGALRM handler and cleared when the key is regenerated.
1.66 markus 153: */
1.132.2.1! jason 154: int key_do_regen = 0;
1.1 deraadt 155:
156: /* This is set to true when SIGHUP is received. */
157: int received_sighup = 0;
158:
1.96 markus 159: /* session identifier, used by RSA-auth */
1.132.2.1! jason 160: u_char session_id[16];
1.96 markus 161:
1.108 markus 162: /* same for ssh2 */
1.132.2.1! jason 163: u_char *session_id2 = NULL;
1.108 markus 164: int session_id2_len = 0;
165:
1.125 markus 166: /* record remote hostname or ip */
1.132.2.1! jason 167: u_int utmp_len = MAXHOSTNAMELEN;
1.125 markus 168:
1.1 deraadt 169: /* Prototypes for various functions defined later in this file. */
1.132.2.1! jason 170: void do_ssh1_kex(void);
! 171: void do_ssh2_kex(void);
1.87 markus 172:
1.129 provos 173: void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *);
174: void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *);
175:
1.87 markus 176: /*
1.75 markus 177: * Close all listening sockets
178: */
179: void
180: close_listen_socks(void)
181: {
182: int i;
183: for (i = 0; i < num_listen_socks; i++)
184: close(listen_socks[i]);
185: num_listen_socks = -1;
186: }
187:
188: /*
1.65 deraadt 189: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
190: * the effect is to reread the configuration file (and to regenerate
191: * the server key).
192: */
1.105 markus 193: void
1.64 markus 194: sighup_handler(int sig)
1.1 deraadt 195: {
1.64 markus 196: received_sighup = 1;
197: signal(SIGHUP, sighup_handler);
1.1 deraadt 198: }
199:
1.65 deraadt 200: /*
201: * Called from the main program after receiving SIGHUP.
202: * Restarts the server.
203: */
1.105 markus 204: void
1.132.2.1! jason 205: sighup_restart(void)
1.1 deraadt 206: {
1.64 markus 207: log("Received SIGHUP; restarting.");
1.75 markus 208: close_listen_socks();
1.64 markus 209: execv(saved_argv[0], saved_argv);
1.132.2.1! jason 210: log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno));
1.64 markus 211: exit(1);
1.1 deraadt 212: }
213:
1.65 deraadt 214: /*
215: * Generic signal handler for terminating signals in the master daemon.
216: * These close the listen socket; not closing it seems to cause "Address
217: * already in use" problems on some machines, which is inconvenient.
218: */
1.105 markus 219: void
1.64 markus 220: sigterm_handler(int sig)
1.1 deraadt 221: {
1.64 markus 222: log("Received signal %d; terminating.", sig);
1.75 markus 223: close_listen_socks();
1.113 markus 224: unlink(options.pid_file);
1.64 markus 225: exit(255);
1.1 deraadt 226: }
227:
1.65 deraadt 228: /*
229: * SIGCHLD handler. This is called whenever a child dies. This will then
230: * reap any zombies left by exited c.
231: */
1.105 markus 232: void
1.64 markus 233: main_sigchld_handler(int sig)
1.1 deraadt 234: {
1.64 markus 235: int save_errno = errno;
236: int status;
1.60 deraadt 237:
1.64 markus 238: while (waitpid(-1, &status, WNOHANG) > 0)
239: ;
1.60 deraadt 240:
1.64 markus 241: signal(SIGCHLD, main_sigchld_handler);
242: errno = save_errno;
1.1 deraadt 243: }
244:
1.65 deraadt 245: /*
246: * Signal handler for the alarm after the login grace period has expired.
247: */
1.105 markus 248: void
1.64 markus 249: grace_alarm_handler(int sig)
1.1 deraadt 250: {
1.64 markus 251: /* Close the connection. */
252: packet_close();
253:
254: /* Log error and exit. */
255: fatal("Timeout before authentication for %s.", get_remote_ipaddr());
1.62 markus 256: }
257:
1.65 deraadt 258: /*
259: * Signal handler for the key regeneration alarm. Note that this
260: * alarm only occurs in the daemon waiting for connections, and it does not
261: * do anything with the private key or random state before forking.
262: * Thus there should be no concurrency control/asynchronous execution
263: * problems.
264: */
1.132.2.1! jason 265: void
! 266: generate_empheral_server_key(void)
! 267: {
! 268: log("Generating %s%d bit RSA key.", sensitive_data.server_key ? "new " : "",
! 269: options.server_key_bits);
! 270: if (sensitive_data.server_key != NULL)
! 271: key_free(sensitive_data.server_key);
! 272: sensitive_data.server_key = key_generate(KEY_RSA1, options.server_key_bits);
! 273: arc4random_stir();
! 274: log("RSA key generation complete.");
! 275: }
! 276:
1.105 markus 277: void
1.64 markus 278: key_regeneration_alarm(int sig)
1.1 deraadt 279: {
1.64 markus 280: int save_errno = errno;
1.132.2.1! jason 281: signal(SIGALRM, SIG_DFL);
1.64 markus 282: errno = save_errno;
1.132.2.1! jason 283: key_do_regen = 1;
1.98 markus 284: }
285:
1.96 markus 286: void
287: sshd_exchange_identification(int sock_in, int sock_out)
288: {
1.102 markus 289: int i, mismatch;
1.96 markus 290: int remote_major, remote_minor;
1.102 markus 291: int major, minor;
1.96 markus 292: char *s;
293: char buf[256]; /* Must not be larger than remote_version. */
294: char remote_version[256]; /* Must be at least as big as buf. */
295:
1.103 markus 296: if ((options.protocol & SSH_PROTO_1) &&
297: (options.protocol & SSH_PROTO_2)) {
1.102 markus 298: major = PROTOCOL_MAJOR_1;
299: minor = 99;
300: } else if (options.protocol & SSH_PROTO_2) {
301: major = PROTOCOL_MAJOR_2;
302: minor = PROTOCOL_MINOR_2;
303: } else {
304: major = PROTOCOL_MAJOR_1;
305: minor = PROTOCOL_MINOR_1;
306: }
307: snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
1.96 markus 308: server_version_string = xstrdup(buf);
309:
310: if (client_version_string == NULL) {
311: /* Send our protocol version identification. */
312: if (atomicio(write, sock_out, server_version_string, strlen(server_version_string))
313: != strlen(server_version_string)) {
314: log("Could not write ident string to %s.", get_remote_ipaddr());
315: fatal_cleanup();
316: }
317:
1.132.2.1! jason 318: /* Read other side's version identification. */
! 319: memset(buf, 0, sizeof(buf));
1.96 markus 320: for (i = 0; i < sizeof(buf) - 1; i++) {
1.119 markus 321: if (atomicio(read, sock_in, &buf[i], 1) != 1) {
1.96 markus 322: log("Did not receive ident string from %s.", get_remote_ipaddr());
323: fatal_cleanup();
324: }
325: if (buf[i] == '\r') {
326: buf[i] = '\n';
327: buf[i + 1] = 0;
1.132 markus 328: /* Kludge for F-Secure Macintosh < 1.0.2 */
329: if (i == 12 &&
330: strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
331: break;
1.96 markus 332: continue;
333: }
334: if (buf[i] == '\n') {
335: /* buf[i] == '\n' */
336: buf[i + 1] = 0;
337: break;
338: }
339: }
340: buf[sizeof(buf) - 1] = 0;
341: client_version_string = xstrdup(buf);
342: }
343:
344: /*
345: * Check that the versions match. In future this might accept
346: * several versions and set appropriate flags to handle them.
347: */
348: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
349: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 350: s = "Protocol mismatch.\n";
1.96 markus 351: (void) atomicio(write, sock_out, s, strlen(s));
352: close(sock_in);
353: close(sock_out);
354: log("Bad protocol version identification '%.100s' from %s",
355: client_version_string, get_remote_ipaddr());
356: fatal_cleanup();
357: }
358: debug("Client protocol version %d.%d; client software version %.100s",
359: remote_major, remote_minor, remote_version);
360:
1.98 markus 361: compat_datafellows(remote_version);
362:
1.102 markus 363: mismatch = 0;
1.96 markus 364: switch(remote_major) {
365: case 1:
1.108 markus 366: if (remote_minor == 99) {
367: if (options.protocol & SSH_PROTO_2)
368: enable_compat20();
369: else
370: mismatch = 1;
371: break;
372: }
1.102 markus 373: if (!(options.protocol & SSH_PROTO_1)) {
374: mismatch = 1;
375: break;
376: }
1.96 markus 377: if (remote_minor < 3) {
1.121 provos 378: packet_disconnect("Your ssh version is too old and "
1.96 markus 379: "is no longer supported. Please install a newer version.");
380: } else if (remote_minor == 3) {
381: /* note that this disables agent-forwarding */
382: enable_compat13();
383: }
1.102 markus 384: break;
1.98 markus 385: case 2:
1.102 markus 386: if (options.protocol & SSH_PROTO_2) {
1.98 markus 387: enable_compat20();
388: break;
389: }
1.99 markus 390: /* FALLTHROUGH */
1.105 markus 391: default:
1.102 markus 392: mismatch = 1;
393: break;
394: }
395: chop(server_version_string);
396: chop(client_version_string);
397: debug("Local version string %.200s", server_version_string);
398:
399: if (mismatch) {
1.96 markus 400: s = "Protocol major versions differ.\n";
401: (void) atomicio(write, sock_out, s, strlen(s));
402: close(sock_in);
403: close(sock_out);
1.102 markus 404: log("Protocol major versions differ for %s: %.200s vs. %.200s",
405: get_remote_ipaddr(),
406: server_version_string, client_version_string);
1.96 markus 407: fatal_cleanup();
408: }
1.108 markus 409: if (compat20)
410: packet_set_ssh2_format();
411: }
412:
413:
1.132.2.1! jason 414: /* Destroy the host and server keys. They will no longer be needed. */
1.108 markus 415: void
416: destroy_sensitive_data(void)
417: {
1.132.2.1! jason 418: int i;
! 419:
! 420: if (sensitive_data.server_key) {
! 421: key_free(sensitive_data.server_key);
! 422: sensitive_data.server_key = NULL;
! 423: }
! 424: for(i = 0; i < options.num_host_key_files; i++) {
! 425: if (sensitive_data.host_keys[i]) {
! 426: key_free(sensitive_data.host_keys[i]);
! 427: sensitive_data.host_keys[i] = NULL;
! 428: }
! 429: }
! 430: sensitive_data.ssh1_host_key = NULL;
! 431: }
! 432: Key *
! 433: load_private_key_autodetect(const char *filename)
! 434: {
! 435: struct stat st;
! 436: int type;
! 437: Key *public, *private;
! 438:
! 439: if (stat(filename, &st) < 0) {
! 440: perror(filename);
! 441: return NULL;
! 442: }
! 443: /*
! 444: * try to load the public key. right now this only works for RSA1,
! 445: * since SSH2 keys are fully encrypted
! 446: */
! 447: type = KEY_RSA1;
! 448: public = key_new(type);
! 449: if (!load_public_key(filename, public, NULL)) {
! 450: /* ok, so we will assume this is 'some' key */
! 451: type = KEY_UNSPEC;
! 452: }
! 453: key_free(public);
! 454:
! 455: /* Ok, try key with empty passphrase */
! 456: private = key_new(type);
! 457: if (load_private_key(filename, "", private, NULL)) {
! 458: debug("load_private_key_autodetect: type %d %s",
! 459: private->type, key_type(private));
! 460: return private;
! 461: }
! 462: key_free(private);
! 463: return NULL;
! 464: }
! 465:
! 466: char *
! 467: list_hostkey_types(void)
! 468: {
! 469: static char buf[1024];
! 470: int i;
! 471: buf[0] = '\0';
! 472: for(i = 0; i < options.num_host_key_files; i++) {
! 473: Key *key = sensitive_data.host_keys[i];
! 474: if (key == NULL)
! 475: continue;
! 476: switch(key->type) {
! 477: case KEY_RSA:
! 478: case KEY_DSA:
! 479: strlcat(buf, key_ssh_name(key), sizeof buf);
! 480: strlcat(buf, ",", sizeof buf);
! 481: break;
! 482: }
! 483: }
! 484: i = strlen(buf);
! 485: if (i > 0 && buf[i-1] == ',')
! 486: buf[i-1] = '\0';
! 487: debug("list_hostkey_types: %s", buf);
! 488: return buf;
! 489: }
! 490:
! 491: Key *
! 492: get_hostkey_by_type(int type)
! 493: {
! 494: int i;
! 495: for(i = 0; i < options.num_host_key_files; i++) {
! 496: Key *key = sensitive_data.host_keys[i];
! 497: if (key != NULL && key->type == type)
! 498: return key;
! 499: }
! 500: return NULL;
1.96 markus 501: }
502:
1.124 markus 503: /*
504: * returns 1 if connection should be dropped, 0 otherwise.
505: * dropping starts at connection #max_startups_begin with a probability
506: * of (max_startups_rate/100). the probability increases linearly until
507: * all connections are dropped for startups > max_startups
508: */
509: int
510: drop_connection(int startups)
511: {
512: double p, r;
513:
514: if (startups < options.max_startups_begin)
515: return 0;
516: if (startups >= options.max_startups)
517: return 1;
518: if (options.max_startups_rate == 100)
519: return 1;
520:
521: p = 100 - options.max_startups_rate;
522: p *= startups - options.max_startups_begin;
523: p /= (double) (options.max_startups - options.max_startups_begin);
524: p += options.max_startups_rate;
525: p /= 100.0;
526: r = arc4random() / (double) UINT_MAX;
527:
528: debug("drop_connection: p %g, r %g", p, r);
529: return (r < p) ? 1 : 0;
530: }
531:
1.120 markus 532: int *startup_pipes = NULL; /* options.max_startup sized array of fd ints */
533: int startup_pipe; /* in child */
534:
1.65 deraadt 535: /*
536: * Main program for the daemon.
537: */
1.2 provos 538: int
539: main(int ac, char **av)
1.1 deraadt 540: {
1.64 markus 541: extern char *optarg;
542: extern int optind;
1.120 markus 543: int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
1.107 deraadt 544: pid_t pid;
1.75 markus 545: socklen_t fromlen;
546: fd_set *fdset;
547: struct sockaddr_storage from;
1.64 markus 548: const char *remote_ip;
549: int remote_port;
550: FILE *f;
551: struct linger linger;
1.75 markus 552: struct addrinfo *ai;
553: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
554: int listen_sock, maxfd;
1.120 markus 555: int startup_p[2];
556: int startups = 0;
1.132.2.1! jason 557: int ret, key_used = 0;
1.64 markus 558:
1.132.2.1! jason 559: /* Save argv. */
1.64 markus 560: saved_argv = av;
561:
562: /* Initialize configuration options to their default values. */
563: initialize_server_options(&options);
564:
565: /* Parse command-line arguments. */
1.132.2.1! jason 566: while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDiqQ46")) != -1) {
1.64 markus 567: switch (opt) {
1.75 markus 568: case '4':
569: IPv4or6 = AF_INET;
570: break;
571: case '6':
572: IPv4or6 = AF_INET6;
573: break;
1.64 markus 574: case 'f':
575: config_file_name = optarg;
576: break;
577: case 'd':
1.127 markus 578: if (0 == debug_flag) {
579: debug_flag = 1;
580: options.log_level = SYSLOG_LEVEL_DEBUG1;
581: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
582: options.log_level++;
583: } else {
584: fprintf(stderr, "Too high debugging level.\n");
585: exit(1);
586: }
1.64 markus 587: break;
1.132.2.1! jason 588: case 'D':
! 589: no_daemon_flag = 1;
! 590: break;
1.64 markus 591: case 'i':
592: inetd_flag = 1;
593: break;
594: case 'Q':
1.132.2.1! jason 595: /* ignored */
1.64 markus 596: break;
597: case 'q':
598: options.log_level = SYSLOG_LEVEL_QUIET;
599: break;
600: case 'b':
601: options.server_key_bits = atoi(optarg);
602: break;
603: case 'p':
1.75 markus 604: options.ports_from_cmdline = 1;
1.127 markus 605: if (options.num_ports >= MAX_PORTS) {
606: fprintf(stderr, "too many ports.\n");
607: exit(1);
608: }
1.75 markus 609: options.ports[options.num_ports++] = atoi(optarg);
1.64 markus 610: break;
611: case 'g':
612: options.login_grace_time = atoi(optarg);
613: break;
614: case 'k':
615: options.key_regeneration_time = atoi(optarg);
616: break;
617: case 'h':
1.132.2.1! jason 618: if (options.num_host_key_files >= MAX_HOSTKEYS) {
! 619: fprintf(stderr, "too many host keys.\n");
! 620: exit(1);
! 621: }
! 622: options.host_key_files[options.num_host_key_files++] = optarg;
1.64 markus 623: break;
624: case 'V':
625: client_version_string = optarg;
626: /* only makes sense with inetd_flag, i.e. no listen() */
627: inetd_flag = 1;
628: break;
1.125 markus 629: case 'u':
630: utmp_len = atoi(optarg);
631: break;
1.64 markus 632: case '?':
633: default:
634: fprintf(stderr, "sshd version %s\n", SSH_VERSION);
1.132.2.1! jason 635: fprintf(stderr, "Usage: %s [options]\n", __progname);
1.64 markus 636: fprintf(stderr, "Options:\n");
1.132.2.1! jason 637: fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
1.127 markus 638: fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
1.64 markus 639: fprintf(stderr, " -i Started from inetd\n");
1.132.2.1! jason 640: fprintf(stderr, " -D Do not fork into daemon mode\n");
1.64 markus 641: fprintf(stderr, " -q Quiet (no logging)\n");
642: fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
643: fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
1.132.2.1! jason 644: fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
1.64 markus 645: fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
646: fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
1.132.2.1! jason 647: _PATH_HOST_KEY_FILE);
1.125 markus 648: fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
1.75 markus 649: fprintf(stderr, " -4 Use IPv4 only\n");
650: fprintf(stderr, " -6 Use IPv6 only\n");
1.64 markus 651: exit(1);
652: }
653: }
654:
1.75 markus 655: /*
656: * Force logging to stderr until we have loaded the private host
657: * key (unless started from inetd)
658: */
1.132.2.1! jason 659: log_init(__progname,
1.75 markus 660: options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
661: options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
1.132.2.1! jason 662: !inetd_flag);
1.75 markus 663:
1.64 markus 664: /* Read server configuration options from the configuration file. */
665: read_server_config(&options, config_file_name);
666:
667: /* Fill in default values for those options not explicitly set. */
668: fill_default_server_options(&options);
669:
670: /* Check that there are no remaining arguments. */
671: if (optind < ac) {
672: fprintf(stderr, "Extra argument %s.\n", av[optind]);
673: exit(1);
674: }
675:
676: debug("sshd version %.100s", SSH_VERSION);
677:
1.132.2.1! jason 678: /* load private host keys */
! 679: sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*));
! 680: for(i = 0; i < options.num_host_key_files; i++)
! 681: sensitive_data.host_keys[i] = NULL;
! 682: sensitive_data.server_key = NULL;
! 683: sensitive_data.ssh1_host_key = NULL;
! 684: sensitive_data.have_ssh1_key = 0;
! 685: sensitive_data.have_ssh2_key = 0;
! 686:
! 687: for(i = 0; i < options.num_host_key_files; i++) {
! 688: Key *key = load_private_key_autodetect(options.host_key_files[i]);
! 689: if (key == NULL) {
1.108 markus 690: error("Could not load host key: %.200s: %.100s",
1.132.2.1! jason 691: options.host_key_files[i], strerror(errno));
! 692: continue;
1.108 markus 693: }
1.132.2.1! jason 694: switch(key->type){
! 695: case KEY_RSA1:
! 696: sensitive_data.ssh1_host_key = key;
! 697: sensitive_data.have_ssh1_key = 1;
! 698: break;
! 699: case KEY_RSA:
! 700: case KEY_DSA:
! 701: sensitive_data.have_ssh2_key = 1;
! 702: break;
1.108 markus 703: }
1.132.2.1! jason 704: sensitive_data.host_keys[i] = key;
! 705: }
! 706: if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
! 707: log("Disabling protocol version 1. Could not load host key");
! 708: options.protocol &= ~SSH_PROTO_1;
! 709: }
! 710: if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
! 711: log("Disabling protocol version 2. Could not load host key");
! 712: options.protocol &= ~SSH_PROTO_2;
1.108 markus 713: }
1.132.2.1! jason 714: if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1.108 markus 715: log("sshd: no hostkeys available -- exiting.\n");
1.64 markus 716: exit(1);
717: }
718:
1.108 markus 719: /* Check certain values for sanity. */
720: if (options.protocol & SSH_PROTO_1) {
721: if (options.server_key_bits < 512 ||
722: options.server_key_bits > 32768) {
723: fprintf(stderr, "Bad server key size.\n");
724: exit(1);
725: }
726: /*
727: * Check that server and host key lengths differ sufficiently. This
728: * is necessary to make double encryption work with rsaref. Oh, I
729: * hate software patents. I dont know if this can go? Niels
730: */
731: if (options.server_key_bits >
1.132.2.1! jason 732: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED &&
1.108 markus 733: options.server_key_bits <
1.132.2.1! jason 734: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1.108 markus 735: options.server_key_bits =
1.132.2.1! jason 736: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED;
1.108 markus 737: debug("Forcing server key to %d bits to make it differ from host key.",
738: options.server_key_bits);
739: }
740: }
741:
742: /* Initialize the log (it is reinitialized below in case we forked). */
1.64 markus 743: if (debug_flag && !inetd_flag)
744: log_stderr = 1;
1.132.2.1! jason 745: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 746:
1.108 markus 747: /*
748: * If not in debugging mode, and not started from inetd, disconnect
749: * from the controlling terminal, and fork. The original process
750: * exits.
751: */
1.132.2.1! jason 752: if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1.1 deraadt 753: #ifdef TIOCNOTTY
1.64 markus 754: int fd;
1.1 deraadt 755: #endif /* TIOCNOTTY */
1.64 markus 756: if (daemon(0, 0) < 0)
757: fatal("daemon() failed: %.200s", strerror(errno));
758:
759: /* Disconnect from the controlling tty. */
1.1 deraadt 760: #ifdef TIOCNOTTY
1.132.2.1! jason 761: fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1.64 markus 762: if (fd >= 0) {
763: (void) ioctl(fd, TIOCNOTTY, NULL);
764: close(fd);
765: }
766: #endif /* TIOCNOTTY */
767: }
768: /* Reinitialize the log (because of the fork above). */
1.132.2.1! jason 769: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.64 markus 770:
771: /* Initialize the random number generator. */
772: arc4random_stir();
773:
774: /* Chdir to the root directory so that the current disk can be
775: unmounted if desired. */
776: chdir("/");
777:
778: /* Start listening for a socket, unless started from inetd. */
779: if (inetd_flag) {
780: int s1, s2;
781: s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
782: s2 = dup(s1);
783: sock_in = dup(0);
784: sock_out = dup(1);
1.123 djm 785: startup_pipe = -1;
1.108 markus 786: /*
787: * We intentionally do not close the descriptors 0, 1, and 2
788: * as our code for setting the descriptors won\'t work if
789: * ttyfd happens to be one of those.
790: */
1.64 markus 791: debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1.132.2.1! jason 792: if (options.protocol & SSH_PROTO_1)
! 793: generate_empheral_server_key();
1.64 markus 794: } else {
1.75 markus 795: for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
796: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
797: continue;
798: if (num_listen_socks >= MAX_LISTEN_SOCKS)
799: fatal("Too many listen sockets. "
800: "Enlarge MAX_LISTEN_SOCKS");
801: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
802: ntop, sizeof(ntop), strport, sizeof(strport),
803: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
804: error("getnameinfo failed");
805: continue;
806: }
807: /* Create socket for listening. */
808: listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
809: if (listen_sock < 0) {
810: /* kernel may not support ipv6 */
811: verbose("socket: %.100s", strerror(errno));
812: continue;
813: }
814: if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
815: error("listen_sock O_NONBLOCK: %s", strerror(errno));
816: close(listen_sock);
817: continue;
818: }
819: /*
820: * Set socket options. We try to make the port
821: * reusable and have it close as fast as possible
822: * without waiting in unnecessary wait states on
823: * close.
824: */
825: setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
826: (void *) &on, sizeof(on));
827: linger.l_onoff = 1;
828: linger.l_linger = 5;
829: setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
830: (void *) &linger, sizeof(linger));
831:
832: debug("Bind to port %s on %s.", strport, ntop);
833:
834: /* Bind the socket to the desired port. */
835: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
836: error("Bind to port %s on %s failed: %.200s.",
837: strport, ntop, strerror(errno));
838: close(listen_sock);
839: continue;
840: }
841: listen_socks[num_listen_socks] = listen_sock;
842: num_listen_socks++;
843:
844: /* Start listening on the port. */
845: log("Server listening on %s port %s.", ntop, strport);
846: if (listen(listen_sock, 5) < 0)
847: fatal("listen: %.100s", strerror(errno));
848:
1.64 markus 849: }
1.75 markus 850: freeaddrinfo(options.listen_addrs);
851:
852: if (!num_listen_socks)
853: fatal("Cannot bind any address.");
854:
1.64 markus 855: if (!debug_flag) {
1.66 markus 856: /*
1.132.2.1! jason 857: * Record our pid in /var/run/sshd.pid to make it
! 858: * easier to kill the correct sshd. We don't want to
! 859: * do this before the bind above because the bind will
1.66 markus 860: * fail if there already is a daemon, and this will
861: * overwrite any old pid in the file.
862: */
1.112 markus 863: f = fopen(options.pid_file, "w");
1.64 markus 864: if (f) {
1.132.2.1! jason 865: fprintf(f, "%u\n", (u_int) getpid());
1.64 markus 866: fclose(f);
867: }
868: }
1.132.2.1! jason 869: if (options.protocol & SSH_PROTO_1)
! 870: generate_empheral_server_key();
1.64 markus 871:
872: /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
873: signal(SIGHUP, sighup_handler);
1.120 markus 874:
1.64 markus 875: signal(SIGTERM, sigterm_handler);
876: signal(SIGQUIT, sigterm_handler);
877:
878: /* Arrange SIGCHLD to be caught. */
879: signal(SIGCHLD, main_sigchld_handler);
880:
1.75 markus 881: /* setup fd set for listen */
1.120 markus 882: fdset = NULL;
1.75 markus 883: maxfd = 0;
884: for (i = 0; i < num_listen_socks; i++)
885: if (listen_socks[i] > maxfd)
886: maxfd = listen_socks[i];
1.120 markus 887: /* pipes connected to unauthenticated childs */
888: startup_pipes = xmalloc(options.max_startups * sizeof(int));
889: for (i = 0; i < options.max_startups; i++)
890: startup_pipes[i] = -1;
1.75 markus 891:
1.66 markus 892: /*
893: * Stay listening for connections until the system crashes or
894: * the daemon is killed with a signal.
895: */
1.64 markus 896: for (;;) {
897: if (received_sighup)
898: sighup_restart();
1.120 markus 899: if (fdset != NULL)
900: xfree(fdset);
1.132.2.1! jason 901: fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1.120 markus 902: fdset = (fd_set *)xmalloc(fdsetsz);
1.75 markus 903: memset(fdset, 0, fdsetsz);
1.120 markus 904:
1.75 markus 905: for (i = 0; i < num_listen_socks; i++)
906: FD_SET(listen_socks[i], fdset);
1.120 markus 907: for (i = 0; i < options.max_startups; i++)
908: if (startup_pipes[i] != -1)
909: FD_SET(startup_pipes[i], fdset);
910:
911: /* Wait in select until there is a connection. */
1.132.2.1! jason 912: ret = select(maxfd+1, fdset, NULL, NULL, NULL);
! 913: if (ret < 0 && errno != EINTR)
! 914: error("select: %.100s", strerror(errno));
! 915: if (key_used && key_do_regen) {
! 916: generate_empheral_server_key();
! 917: key_used = 0;
! 918: key_do_regen = 0;
1.75 markus 919: }
1.132.2.1! jason 920: if (ret < 0)
! 921: continue;
! 922:
1.120 markus 923: for (i = 0; i < options.max_startups; i++)
924: if (startup_pipes[i] != -1 &&
925: FD_ISSET(startup_pipes[i], fdset)) {
926: /*
927: * the read end of the pipe is ready
928: * if the child has closed the pipe
1.132.2.1! jason 929: * after successful authentication
1.120 markus 930: * or if the child has died
931: */
932: close(startup_pipes[i]);
933: startup_pipes[i] = -1;
934: startups--;
935: }
1.75 markus 936: for (i = 0; i < num_listen_socks; i++) {
937: if (!FD_ISSET(listen_socks[i], fdset))
1.70 provos 938: continue;
1.120 markus 939: fromlen = sizeof(from);
940: newsock = accept(listen_socks[i], (struct sockaddr *)&from,
941: &fromlen);
942: if (newsock < 0) {
943: if (errno != EINTR && errno != EWOULDBLOCK)
944: error("accept: %.100s", strerror(errno));
945: continue;
946: }
947: if (fcntl(newsock, F_SETFL, 0) < 0) {
948: error("newsock del O_NONBLOCK: %s", strerror(errno));
949: continue;
950: }
1.124 markus 951: if (drop_connection(startups) == 1) {
952: debug("drop connection #%d", startups);
1.120 markus 953: close(newsock);
954: continue;
955: }
956: if (pipe(startup_p) == -1) {
957: close(newsock);
958: continue;
959: }
960:
961: for (j = 0; j < options.max_startups; j++)
962: if (startup_pipes[j] == -1) {
963: startup_pipes[j] = startup_p[0];
964: if (maxfd < startup_p[0])
965: maxfd = startup_p[0];
966: startups++;
967: break;
968: }
1.132.2.1! jason 969:
1.66 markus 970: /*
1.120 markus 971: * Got connection. Fork a child to handle it, unless
972: * we are in debugging mode.
1.66 markus 973: */
1.120 markus 974: if (debug_flag) {
1.66 markus 975: /*
1.120 markus 976: * In debugging mode. Close the listening
977: * socket, and start processing the
978: * connection without forking.
1.66 markus 979: */
1.120 markus 980: debug("Server will not fork when running in debugging mode.");
1.75 markus 981: close_listen_socks();
1.64 markus 982: sock_in = newsock;
983: sock_out = newsock;
1.122 deraadt 984: startup_pipe = -1;
1.120 markus 985: pid = getpid();
1.64 markus 986: break;
1.120 markus 987: } else {
988: /*
989: * Normal production daemon. Fork, and have
990: * the child process the connection. The
991: * parent continues listening.
992: */
993: if ((pid = fork()) == 0) {
994: /*
995: * Child. Close the listening and max_startup
996: * sockets. Start using the accepted socket.
997: * Reinitialize logging (since our pid has
998: * changed). We break out of the loop to handle
999: * the connection.
1000: */
1001: startup_pipe = startup_p[1];
1002: for (j = 0; j < options.max_startups; j++)
1003: if (startup_pipes[j] != -1)
1004: close(startup_pipes[j]);
1005: close_listen_socks();
1006: sock_in = newsock;
1007: sock_out = newsock;
1.132.2.1! jason 1008: log_init(__progname, options.log_level, options.log_facility, log_stderr);
1.120 markus 1009: break;
1010: }
1.64 markus 1011: }
1012:
1.120 markus 1013: /* Parent. Stay in the loop. */
1014: if (pid < 0)
1015: error("fork: %.100s", strerror(errno));
1016: else
1017: debug("Forked child %d.", pid);
1018:
1019: close(startup_p[1]);
1.1 deraadt 1020:
1.120 markus 1021: /* Mark that the key has been used (it was "given" to the child). */
1.132.2.1! jason 1022: if ((options.protocol & SSH_PROTO_1) &&
! 1023: key_used == 0) {
! 1024: /* Schedule server key regeneration alarm. */
! 1025: signal(SIGALRM, key_regeneration_alarm);
! 1026: alarm(options.key_regeneration_time);
! 1027: key_used = 1;
! 1028: }
1.1 deraadt 1029:
1.120 markus 1030: arc4random_stir();
1.1 deraadt 1031:
1.120 markus 1032: /* Close the new socket (the child is now taking care of it). */
1033: close(newsock);
1034: }
1.75 markus 1035: /* child process check (or debug mode) */
1036: if (num_listen_socks < 0)
1037: break;
1.64 markus 1038: }
1.1 deraadt 1039: }
1040:
1.64 markus 1041: /* This is the child processing a new connection. */
1042:
1.66 markus 1043: /*
1044: * Disable the key regeneration alarm. We will not regenerate the
1045: * key since we are no longer in a position to give it to anyone. We
1046: * will not restart on SIGHUP since it no longer makes sense.
1047: */
1.64 markus 1048: alarm(0);
1049: signal(SIGALRM, SIG_DFL);
1050: signal(SIGHUP, SIG_DFL);
1051: signal(SIGTERM, SIG_DFL);
1052: signal(SIGQUIT, SIG_DFL);
1053: signal(SIGCHLD, SIG_DFL);
1054:
1.66 markus 1055: /*
1056: * Set socket options for the connection. We want the socket to
1057: * close as fast as possible without waiting for anything. If the
1058: * connection is not a socket, these will do nothing.
1059: */
1060: /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
1.64 markus 1061: linger.l_onoff = 1;
1062: linger.l_linger = 5;
1063: setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
1064:
1.132.2.1! jason 1065: /* Set keepalives if requested. */
! 1066: if (options.keepalives &&
! 1067: setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
! 1068: sizeof(on)) < 0)
! 1069: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
! 1070:
1.66 markus 1071: /*
1072: * Register our connection. This turns encryption off because we do
1073: * not have a key.
1074: */
1.64 markus 1075: packet_set_connection(sock_in, sock_out);
1.1 deraadt 1076:
1.64 markus 1077: remote_port = get_remote_port();
1078: remote_ip = get_remote_ipaddr();
1.52 markus 1079:
1.64 markus 1080: /* Check whether logins are denied from this host. */
1.37 dugsong 1081: #ifdef LIBWRAP
1.75 markus 1082: /* XXX LIBWRAP noes not know about IPv6 */
1.64 markus 1083: {
1084: struct request_info req;
1.37 dugsong 1085:
1.132.2.1! jason 1086: request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, NULL);
1.64 markus 1087: fromhost(&req);
1.37 dugsong 1088:
1.64 markus 1089: if (!hosts_access(&req)) {
1090: close(sock_in);
1091: close(sock_out);
1092: refuse(&req);
1093: }
1.75 markus 1094: /*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
1.64 markus 1095: }
1.75 markus 1096: #endif /* LIBWRAP */
1.64 markus 1097: /* Log the connection. */
1098: verbose("Connection from %.500s port %d", remote_ip, remote_port);
1.1 deraadt 1099:
1.66 markus 1100: /*
1101: * We don\'t want to listen forever unless the other side
1102: * successfully authenticates itself. So we set up an alarm which is
1103: * cleared after successful authentication. A limit of zero
1104: * indicates no limit. Note that we don\'t set the alarm in debugging
1105: * mode; it is just annoying to have the server exit just when you
1106: * are about to discover the bug.
1107: */
1.64 markus 1108: signal(SIGALRM, grace_alarm_handler);
1109: if (!debug_flag)
1110: alarm(options.login_grace_time);
1111:
1.96 markus 1112: sshd_exchange_identification(sock_in, sock_out);
1.66 markus 1113: /*
1.132.2.1! jason 1114: * Check that the connection comes from a privileged port.
! 1115: * Rhosts-Authentication only makes sense from priviledged
1.66 markus 1116: * programs. Of course, if the intruder has root access on his local
1117: * machine, he can connect from any port. So do not use these
1118: * authentication methods from machines that you do not trust.
1119: */
1.64 markus 1120: if (remote_port >= IPPORT_RESERVED ||
1121: remote_port < IPPORT_RESERVED / 2) {
1.132.2.1! jason 1122: debug("Rhosts Authentication disabled, "
! 1123: "originating port not trusted.");
1.64 markus 1124: options.rhosts_authentication = 0;
1125: }
1.76 markus 1126: #ifdef KRB4
1127: if (!packet_connection_is_ipv4() &&
1128: options.kerberos_authentication) {
1129: debug("Kerberos Authentication disabled, only available for IPv4.");
1130: options.kerberos_authentication = 0;
1131: }
1132: #endif /* KRB4 */
1.132.2.1! jason 1133: #ifdef AFS
! 1134: /* If machine has AFS, set process authentication group. */
! 1135: if (k_hasafs()) {
! 1136: k_setpag();
! 1137: k_unlog();
! 1138: }
! 1139: #endif /* AFS */
1.76 markus 1140:
1.64 markus 1141: packet_set_nonblocking();
1.1 deraadt 1142:
1.77 markus 1143: /* perform the key exchange */
1144: /* authenticate user and start session */
1.98 markus 1145: if (compat20) {
1146: do_ssh2_kex();
1147: do_authentication2();
1148: } else {
1149: do_ssh1_kex();
1150: do_authentication();
1151: }
1.1 deraadt 1152:
1153: #ifdef KRB4
1.64 markus 1154: /* Cleanup user's ticket cache file. */
1155: if (options.kerberos_ticket_cleanup)
1156: (void) dest_tkt();
1.1 deraadt 1157: #endif /* KRB4 */
1158:
1.64 markus 1159: /* The connection has been terminated. */
1160: verbose("Closing connection to %.100s", remote_ip);
1161: packet_close();
1162: exit(0);
1.1 deraadt 1163: }
1164:
1.65 deraadt 1165: /*
1.77 markus 1166: * SSH1 key exchange
1.65 deraadt 1167: */
1.52 markus 1168: void
1.132.2.1! jason 1169: do_ssh1_kex(void)
1.1 deraadt 1170: {
1.64 markus 1171: int i, len;
1.77 markus 1172: int plen, slen;
1.132.2.1! jason 1173: int rsafail = 0;
1.64 markus 1174: BIGNUM *session_key_int;
1.132.2.1! jason 1175: u_char session_key[SSH_SESSION_KEY_LENGTH];
! 1176: u_char cookie[8];
! 1177: u_int cipher_type, auth_mask, protocol_flags;
1.64 markus 1178: u_int32_t rand = 0;
1179:
1.66 markus 1180: /*
1181: * Generate check bytes that the client must send back in the user
1182: * packet in order for it to be accepted; this is used to defy ip
1183: * spoofing attacks. Note that this only works against somebody
1184: * doing IP spoofing from a remote machine; any machine on the local
1185: * network can still see outgoing packets and catch the random
1186: * cookie. This only affects rhosts authentication, and this is one
1187: * of the reasons why it is inherently insecure.
1188: */
1.64 markus 1189: for (i = 0; i < 8; i++) {
1190: if (i % 4 == 0)
1191: rand = arc4random();
1.77 markus 1192: cookie[i] = rand & 0xff;
1.64 markus 1193: rand >>= 8;
1194: }
1195:
1.66 markus 1196: /*
1197: * Send our public key. We include in the packet 64 bits of random
1198: * data that must be matched in the reply in order to prevent IP
1199: * spoofing.
1200: */
1.64 markus 1201: packet_start(SSH_SMSG_PUBLIC_KEY);
1202: for (i = 0; i < 8; i++)
1.77 markus 1203: packet_put_char(cookie[i]);
1.64 markus 1204:
1205: /* Store our public server RSA key. */
1.132.2.1! jason 1206: packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
! 1207: packet_put_bignum(sensitive_data.server_key->rsa->e);
! 1208: packet_put_bignum(sensitive_data.server_key->rsa->n);
1.64 markus 1209:
1210: /* Store our public host RSA key. */
1.132.2.1! jason 1211: packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
! 1212: packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
! 1213: packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1.64 markus 1214:
1215: /* Put protocol flags. */
1216: packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1217:
1218: /* Declare which ciphers we support. */
1.131 markus 1219: packet_put_int(cipher_mask_ssh1(0));
1.64 markus 1220:
1221: /* Declare supported authentication types. */
1222: auth_mask = 0;
1223: if (options.rhosts_authentication)
1224: auth_mask |= 1 << SSH_AUTH_RHOSTS;
1225: if (options.rhosts_rsa_authentication)
1226: auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1227: if (options.rsa_authentication)
1228: auth_mask |= 1 << SSH_AUTH_RSA;
1.1 deraadt 1229: #ifdef KRB4
1.64 markus 1230: if (options.kerberos_authentication)
1231: auth_mask |= 1 << SSH_AUTH_KERBEROS;
1.1 deraadt 1232: #endif
1.5 dugsong 1233: #ifdef AFS
1.64 markus 1234: if (options.kerberos_tgt_passing)
1235: auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1236: if (options.afs_token_passing)
1237: auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
1.1 deraadt 1238: #endif
1.132.2.1! jason 1239: if (options.challenge_reponse_authentication == 1)
1.64 markus 1240: auth_mask |= 1 << SSH_AUTH_TIS;
1241: if (options.password_authentication)
1242: auth_mask |= 1 << SSH_AUTH_PASSWORD;
1243: packet_put_int(auth_mask);
1244:
1245: /* Send the packet and wait for it to be sent. */
1246: packet_send();
1247: packet_write_wait();
1248:
1.132.2.1! jason 1249: debug("Sent %d bit server key and %d bit host key.",
! 1250: BN_num_bits(sensitive_data.server_key->rsa->n),
! 1251: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1.64 markus 1252:
1253: /* Read clients reply (cipher type and session key). */
1254: packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
1255:
1.69 markus 1256: /* Get cipher type and check whether we accept this. */
1.64 markus 1257: cipher_type = packet_get_char();
1.69 markus 1258:
1.131 markus 1259: if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1.69 markus 1260: packet_disconnect("Warning: client selects unsupported cipher.");
1.64 markus 1261:
1262: /* Get check bytes from the packet. These must match those we
1263: sent earlier with the public key packet. */
1264: for (i = 0; i < 8; i++)
1.77 markus 1265: if (cookie[i] != packet_get_char())
1.64 markus 1266: packet_disconnect("IP Spoofing check bytes do not match.");
1267:
1268: debug("Encryption type: %.200s", cipher_name(cipher_type));
1269:
1270: /* Get the encrypted integer. */
1271: session_key_int = BN_new();
1272: packet_get_bignum(session_key_int, &slen);
1273:
1274: protocol_flags = packet_get_int();
1275: packet_set_protocol_flags(protocol_flags);
1276:
1277: packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
1278:
1.66 markus 1279: /*
1280: * Decrypt it using our private server key and private host key (key
1281: * with larger modulus first).
1282: */
1.132.2.1! jason 1283: if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
! 1284: /* Server key has bigger modulus. */
! 1285: if (BN_num_bits(sensitive_data.server_key->rsa->n) <
! 1286: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
! 1287: fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
! 1288: get_remote_ipaddr(),
! 1289: BN_num_bits(sensitive_data.server_key->rsa->n),
! 1290: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
! 1291: SSH_KEY_BITS_RESERVED);
! 1292: }
! 1293: if (rsa_private_decrypt(session_key_int, session_key_int,
! 1294: sensitive_data.server_key->rsa) <= 0)
! 1295: rsafail++;
! 1296: if (rsa_private_decrypt(session_key_int, session_key_int,
! 1297: sensitive_data.ssh1_host_key->rsa) <= 0)
! 1298: rsafail++;
1.64 markus 1299: } else {
1300: /* Host key has bigger modulus (or they are equal). */
1.132.2.1! jason 1301: if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
! 1302: BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
! 1303: fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
! 1304: get_remote_ipaddr(),
! 1305: BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
! 1306: BN_num_bits(sensitive_data.server_key->rsa->n),
! 1307: SSH_KEY_BITS_RESERVED);
! 1308: }
! 1309: if (rsa_private_decrypt(session_key_int, session_key_int,
! 1310: sensitive_data.ssh1_host_key->rsa) < 0)
! 1311: rsafail++;
! 1312: if (rsa_private_decrypt(session_key_int, session_key_int,
! 1313: sensitive_data.server_key->rsa) < 0)
! 1314: rsafail++;
1.64 markus 1315: }
1316:
1.77 markus 1317: compute_session_id(session_id, cookie,
1.132.2.1! jason 1318: sensitive_data.ssh1_host_key->rsa->n,
! 1319: sensitive_data.server_key->rsa->n);
1.64 markus 1320:
1.77 markus 1321: /* Destroy the private and public keys. They will no longer be needed. */
1.108 markus 1322: destroy_sensitive_data();
1.77 markus 1323:
1.66 markus 1324: /*
1325: * Extract session key from the decrypted integer. The key is in the
1326: * least significant 256 bits of the integer; the first byte of the
1327: * key is in the highest bits.
1328: */
1.132.2.1! jason 1329: if (!rsafail) {
! 1330: BN_mask_bits(session_key_int, sizeof(session_key) * 8);
! 1331: len = BN_num_bytes(session_key_int);
! 1332: if (len < 0 || len > sizeof(session_key)) {
! 1333: error("do_connection: bad session key len from %s: "
! 1334: "session_key_int %d > sizeof(session_key) %lu",
! 1335: get_remote_ipaddr(), len, (u_long)sizeof(session_key));
! 1336: rsafail++;
! 1337: } else {
! 1338: memset(session_key, 0, sizeof(session_key));
! 1339: BN_bn2bin(session_key_int,
! 1340: session_key + sizeof(session_key) - len);
! 1341: }
! 1342: }
! 1343: if (rsafail) {
! 1344: log("do_connection: generating a fake encryption key");
! 1345: for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
! 1346: if (i % 4 == 0)
! 1347: rand = arc4random();
! 1348: session_key[i] = rand & 0xff;
! 1349: rand >>= 8;
! 1350: }
! 1351: }
1.77 markus 1352: /* Destroy the decrypted integer. It is no longer needed. */
1353: BN_clear_free(session_key_int);
1354:
1.64 markus 1355: /* Xor the first 16 bytes of the session key with the session id. */
1356: for (i = 0; i < 16; i++)
1357: session_key[i] ^= session_id[i];
1358:
1359: /* Set the session key. From this on all communications will be encrypted. */
1360: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1361:
1362: /* Destroy our copy of the session key. It is no longer needed. */
1363: memset(session_key, 0, sizeof(session_key));
1364:
1365: debug("Received session key; encryption turned on.");
1366:
1367: /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1368: packet_start(SSH_SMSG_SUCCESS);
1369: packet_send();
1370: packet_write_wait();
1.98 markus 1371: }
1372:
1373: /*
1374: * SSH2 key exchange: diffie-hellman-group1-sha1
1375: */
1376: void
1.132.2.1! jason 1377: do_ssh2_kex(void)
1.98 markus 1378: {
1379: Buffer *server_kexinit;
1380: Buffer *client_kexinit;
1.129 provos 1381: int payload_len;
1.98 markus 1382: int i;
1383: Kex *kex;
1384: char *cprop[PROPOSAL_MAX];
1385:
1386: /* KEXINIT */
1.102 markus 1387:
1388: if (options.ciphers != NULL) {
1.105 markus 1389: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1.102 markus 1390: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1391: }
1.132.2.1! jason 1392: if (options.macs != NULL) {
! 1393: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
! 1394: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
! 1395: }
! 1396: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
! 1397:
1.118 markus 1398: server_kexinit = kex_init(myproposal);
1.98 markus 1399: client_kexinit = xmalloc(sizeof(*client_kexinit));
1400: buffer_init(client_kexinit);
1401:
1.118 markus 1402: /* algorithm negotiation */
1403: kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
1404: kex = kex_choose_conf(cprop, myproposal, 1);
1405: for (i = 0; i < PROPOSAL_MAX; i++)
1406: xfree(cprop[i]);
1.98 markus 1407:
1.129 provos 1408: switch (kex->kex_type) {
1409: case DH_GRP1_SHA1:
1410: ssh_dh1_server(kex, client_kexinit, server_kexinit);
1411: break;
1412: case DH_GEX_SHA1:
1413: ssh_dhgex_server(kex, client_kexinit, server_kexinit);
1414: break;
1415: default:
1416: fatal("Unsupported key exchange %d", kex->kex_type);
1417: }
1418:
1419: debug("send SSH2_MSG_NEWKEYS.");
1420: packet_start(SSH2_MSG_NEWKEYS);
1421: packet_send();
1422: packet_write_wait();
1423: debug("done: send SSH2_MSG_NEWKEYS.");
1424:
1425: debug("Wait SSH2_MSG_NEWKEYS.");
1426: packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
1427: debug("GOT SSH2_MSG_NEWKEYS.");
1428:
1429: #ifdef DEBUG_KEXDH
1430: /* send 1st encrypted/maced/compressed message */
1431: packet_start(SSH2_MSG_IGNORE);
1432: packet_put_cstring("markus");
1433: packet_send();
1434: packet_write_wait();
1435: #endif
1436:
1437: debug("done: KEX2.");
1438: }
1439:
1440: /*
1441: * SSH2 key exchange
1442: */
1443:
1444: /* diffie-hellman-group1-sha1 */
1445:
1446: void
1447: ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
1448: {
1.130 markus 1449: #ifdef DEBUG_KEXDH
1450: int i;
1451: #endif
1.129 provos 1452: int payload_len, dlen;
1453: int slen;
1.132.2.1! jason 1454: u_char *signature = NULL;
! 1455: u_char *server_host_key_blob = NULL;
! 1456: u_int sbloblen;
! 1457: u_int klen, kout;
! 1458: u_char *kbuf;
! 1459: u_char *hash;
1.129 provos 1460: BIGNUM *shared_secret = 0;
1461: DH *dh;
1462: BIGNUM *dh_client_pub = 0;
1.132.2.1! jason 1463: Key *hostkey;
! 1464:
! 1465: hostkey = get_hostkey_by_type(kex->hostkey_type);
! 1466: if (hostkey == NULL)
! 1467: fatal("Unsupported hostkey type %d", kex->hostkey_type);
1.129 provos 1468:
1.98 markus 1469: /* KEXDH */
1.132.2.1! jason 1470: /* generate DH key */
! 1471: dh = dh_new_group1(); /* XXX depends on 'kex' */
! 1472: dh_gen_key(dh);
! 1473:
1.98 markus 1474: debug("Wait SSH2_MSG_KEXDH_INIT.");
1475: packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
1476:
1477: /* key, cert */
1478: dh_client_pub = BN_new();
1479: if (dh_client_pub == NULL)
1480: fatal("dh_client_pub == NULL");
1481: packet_get_bignum2(dh_client_pub, &dlen);
1482:
1483: #ifdef DEBUG_KEXDH
1484: fprintf(stderr, "\ndh_client_pub= ");
1.128 markus 1485: BN_print_fp(stderr, dh_client_pub);
1.98 markus 1486: fprintf(stderr, "\n");
1487: debug("bits %d", BN_num_bits(dh_client_pub));
1488: #endif
1489:
1490: #ifdef DEBUG_KEXDH
1491: fprintf(stderr, "\np= ");
1.128 markus 1492: BN_print_fp(stderr, dh->p);
1.98 markus 1493: fprintf(stderr, "\ng= ");
1.128 markus 1494: bn_print(dh->g);
1.98 markus 1495: fprintf(stderr, "\npub= ");
1.128 markus 1496: BN_print_fp(stderr, dh->pub_key);
1.98 markus 1497: fprintf(stderr, "\n");
1.132.2.1! jason 1498: DHparams_print_fp(stderr, dh);
1.98 markus 1499: #endif
1.101 markus 1500: if (!dh_pub_is_valid(dh, dh_client_pub))
1501: packet_disconnect("bad client public DH value");
1.98 markus 1502:
1503: klen = DH_size(dh);
1504: kbuf = xmalloc(klen);
1505: kout = DH_compute_key(kbuf, dh_client_pub, dh);
1506:
1507: #ifdef DEBUG_KEXDH
1508: debug("shared secret: len %d/%d", klen, kout);
1509: fprintf(stderr, "shared secret == ");
1510: for (i = 0; i< kout; i++)
1511: fprintf(stderr, "%02x", (kbuf[i])&0xff);
1512: fprintf(stderr, "\n");
1513: #endif
1514: shared_secret = BN_new();
1515:
1516: BN_bin2bn(kbuf, kout, shared_secret);
1517: memset(kbuf, 0, klen);
1518: xfree(kbuf);
1519:
1.111 markus 1520: /* XXX precompute? */
1.132.2.1! jason 1521: key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
1.98 markus 1522:
1523: /* calc H */ /* XXX depends on 'kex' */
1524: hash = kex_hash(
1525: client_version_string,
1526: server_version_string,
1527: buffer_ptr(client_kexinit), buffer_len(client_kexinit),
1528: buffer_ptr(server_kexinit), buffer_len(server_kexinit),
1529: (char *)server_host_key_blob, sbloblen,
1530: dh_client_pub,
1531: dh->pub_key,
1532: shared_secret
1533: );
1534: buffer_free(client_kexinit);
1535: buffer_free(server_kexinit);
1536: xfree(client_kexinit);
1537: xfree(server_kexinit);
1.132.2.1! jason 1538: BN_free(dh_client_pub);
1.98 markus 1539: #ifdef DEBUG_KEXDH
1.105 markus 1540: fprintf(stderr, "hash == ");
1541: for (i = 0; i< 20; i++)
1542: fprintf(stderr, "%02x", (hash[i])&0xff);
1543: fprintf(stderr, "\n");
1.98 markus 1544: #endif
1.108 markus 1545: /* save session id := H */
1546: /* XXX hashlen depends on KEX */
1547: session_id2_len = 20;
1548: session_id2 = xmalloc(session_id2_len);
1549: memcpy(session_id2, hash, session_id2_len);
1550:
1.98 markus 1551: /* sign H */
1.108 markus 1552: /* XXX hashlen depends on KEX */
1.132.2.1! jason 1553: key_sign(hostkey, &signature, &slen, hash, 20);
1.108 markus 1554:
1555: destroy_sensitive_data();
1.98 markus 1556:
1557: /* send server hostkey, DH pubkey 'f' and singed H */
1558: packet_start(SSH2_MSG_KEXDH_REPLY);
1559: packet_put_string((char *)server_host_key_blob, sbloblen);
1.114 markus 1560: packet_put_bignum2(dh->pub_key); /* f */
1.98 markus 1561: packet_put_string((char *)signature, slen);
1562: packet_send();
1.106 markus 1563: xfree(signature);
1.111 markus 1564: xfree(server_host_key_blob);
1.98 markus 1565: packet_write_wait();
1566:
1567: kex_derive_keys(kex, hash, shared_secret);
1.132.2.1! jason 1568: BN_clear_free(shared_secret);
1.98 markus 1569: packet_set_kex(kex);
1570:
1571: /* have keys, free DH */
1572: DH_free(dh);
1.129 provos 1573: }
1574:
1575: /* diffie-hellman-group-exchange-sha1 */
1.98 markus 1576:
1.129 provos 1577: void
1578: ssh_dhgex_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
1579: {
1.130 markus 1580: #ifdef DEBUG_KEXDH
1581: int i;
1582: #endif
1.129 provos 1583: int payload_len, dlen;
1584: int slen, nbits;
1.132.2.1! jason 1585: u_char *signature = NULL;
! 1586: u_char *server_host_key_blob = NULL;
! 1587: u_int sbloblen;
! 1588: u_int klen, kout;
! 1589: u_char *kbuf;
! 1590: u_char *hash;
1.129 provos 1591: BIGNUM *shared_secret = 0;
1592: DH *dh;
1593: BIGNUM *dh_client_pub = 0;
1.132.2.1! jason 1594: Key *hostkey;
! 1595:
! 1596: hostkey = get_hostkey_by_type(kex->hostkey_type);
! 1597: if (hostkey == NULL)
! 1598: fatal("Unsupported hostkey type %d", kex->hostkey_type);
1.129 provos 1599:
1600: /* KEXDHGEX */
1601: debug("Wait SSH2_MSG_KEX_DH_GEX_REQUEST.");
1602: packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_REQUEST);
1603: nbits = packet_get_int();
1604: dh = choose_dh(nbits);
1605:
1606: debug("Sending SSH2_MSG_KEX_DH_GEX_GROUP.");
1607: packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
1608: packet_put_bignum2(dh->p);
1609: packet_put_bignum2(dh->g);
1.98 markus 1610: packet_send();
1611: packet_write_wait();
1612:
1.132.2.1! jason 1613: /* Compute our exchange value in parallel with the client */
! 1614:
! 1615: dh_gen_key(dh);
! 1616:
1.129 provos 1617: debug("Wait SSH2_MSG_KEX_DH_GEX_INIT.");
1618: packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_INIT);
1619:
1620: /* key, cert */
1621: dh_client_pub = BN_new();
1622: if (dh_client_pub == NULL)
1623: fatal("dh_client_pub == NULL");
1624: packet_get_bignum2(dh_client_pub, &dlen);
1625:
1626: #ifdef DEBUG_KEXDH
1627: fprintf(stderr, "\ndh_client_pub= ");
1628: BN_print_fp(stderr, dh_client_pub);
1629: fprintf(stderr, "\n");
1630: debug("bits %d", BN_num_bits(dh_client_pub));
1631: #endif
1632:
1633: #ifdef DEBUG_KEXDH
1634: fprintf(stderr, "\np= ");
1635: BN_print_fp(stderr, dh->p);
1636: fprintf(stderr, "\ng= ");
1637: bn_print(dh->g);
1638: fprintf(stderr, "\npub= ");
1639: BN_print_fp(stderr, dh->pub_key);
1640: fprintf(stderr, "\n");
1.132.2.1! jason 1641: DHparams_print_fp(stderr, dh);
1.129 provos 1642: #endif
1643: if (!dh_pub_is_valid(dh, dh_client_pub))
1644: packet_disconnect("bad client public DH value");
1645:
1646: klen = DH_size(dh);
1647: kbuf = xmalloc(klen);
1648: kout = DH_compute_key(kbuf, dh_client_pub, dh);
1649:
1650: #ifdef DEBUG_KEXDH
1651: debug("shared secret: len %d/%d", klen, kout);
1652: fprintf(stderr, "shared secret == ");
1653: for (i = 0; i< kout; i++)
1654: fprintf(stderr, "%02x", (kbuf[i])&0xff);
1655: fprintf(stderr, "\n");
1656: #endif
1657: shared_secret = BN_new();
1658:
1659: BN_bin2bn(kbuf, kout, shared_secret);
1660: memset(kbuf, 0, klen);
1661: xfree(kbuf);
1662:
1663: /* XXX precompute? */
1.132.2.1! jason 1664: key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
1.98 markus 1665:
1.129 provos 1666: /* calc H */ /* XXX depends on 'kex' */
1667: hash = kex_hash_gex(
1668: client_version_string,
1669: server_version_string,
1670: buffer_ptr(client_kexinit), buffer_len(client_kexinit),
1671: buffer_ptr(server_kexinit), buffer_len(server_kexinit),
1672: (char *)server_host_key_blob, sbloblen,
1673: nbits, dh->p, dh->g,
1674: dh_client_pub,
1675: dh->pub_key,
1676: shared_secret
1677: );
1678: buffer_free(client_kexinit);
1679: buffer_free(server_kexinit);
1680: xfree(client_kexinit);
1681: xfree(server_kexinit);
1.132.2.1! jason 1682: BN_free(dh_client_pub);
1.100 markus 1683: #ifdef DEBUG_KEXDH
1.129 provos 1684: fprintf(stderr, "hash == ");
1685: for (i = 0; i< 20; i++)
1686: fprintf(stderr, "%02x", (hash[i])&0xff);
1687: fprintf(stderr, "\n");
1688: #endif
1689: /* save session id := H */
1690: /* XXX hashlen depends on KEX */
1691: session_id2_len = 20;
1692: session_id2 = xmalloc(session_id2_len);
1693: memcpy(session_id2, hash, session_id2_len);
1694:
1695: /* sign H */
1696: /* XXX hashlen depends on KEX */
1.132.2.1! jason 1697: key_sign(hostkey, &signature, &slen, hash, 20);
1.129 provos 1698:
1699: destroy_sensitive_data();
1700:
1701: /* send server hostkey, DH pubkey 'f' and singed H */
1702: packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
1703: packet_put_string((char *)server_host_key_blob, sbloblen);
1704: packet_put_bignum2(dh->pub_key); /* f */
1705: packet_put_string((char *)signature, slen);
1.98 markus 1706: packet_send();
1.129 provos 1707: xfree(signature);
1708: xfree(server_host_key_blob);
1.98 markus 1709: packet_write_wait();
1.129 provos 1710:
1711: kex_derive_keys(kex, hash, shared_secret);
1.132.2.1! jason 1712: BN_clear_free(shared_secret);
1.129 provos 1713: packet_set_kex(kex);
1714:
1715: /* have keys, free DH */
1716: DH_free(dh);
1.1 deraadt 1717: }
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