Annotation of src/usr.bin/ssh/sshd.c, Revision 1.106
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
5: * Created: Fri Mar 17 17:09:28 1995 ylo
6: * This program is the ssh daemon. It listens for connections from clients, and
7: * performs authentication, executes use commands or shell, and forwards
8: * information to/from the application to the user client over an encrypted
9: * connection. This can also handle forwarding of X11, TCP/IP, and authentication
10: * agent connections.
1.98 markus 11: *
12: * SSH2 implementation,
13: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.65 deraadt 14: */
1.1 deraadt 15:
16: #include "includes.h"
1.106 ! markus 17: RCSID("$OpenBSD: sshd.c,v 1.105 2000/04/14 10:30:33 markus Exp $");
1.1 deraadt 18:
19: #include "xmalloc.h"
20: #include "rsa.h"
21: #include "ssh.h"
22: #include "pty.h"
23: #include "packet.h"
24: #include "cipher.h"
25: #include "mpaux.h"
26: #include "servconf.h"
27: #include "uidswap.h"
1.33 markus 28: #include "compat.h"
1.96 markus 29: #include "buffer.h"
30:
1.98 markus 31: #include "ssh2.h"
1.104 markus 32: #include <openssl/dh.h>
33: #include <openssl/bn.h>
34: #include <openssl/hmac.h>
1.98 markus 35: #include "kex.h"
1.104 markus 36: #include <openssl/dsa.h>
37: #include <openssl/rsa.h>
1.96 markus 38: #include "key.h"
1.98 markus 39: #include "dsa.h"
1.96 markus 40:
41: #include "auth.h"
1.98 markus 42: #include "myproposal.h"
1.1 deraadt 43:
44: #ifdef LIBWRAP
45: #include <tcpd.h>
46: #include <syslog.h>
47: int allow_severity = LOG_INFO;
48: int deny_severity = LOG_WARNING;
49: #endif /* LIBWRAP */
50:
51: #ifndef O_NOCTTY
52: #define O_NOCTTY 0
53: #endif
54:
55: /* Server configuration options. */
56: ServerOptions options;
57:
58: /* Name of the server configuration file. */
59: char *config_file_name = SERVER_CONFIG_FILE;
60:
1.105 markus 61: /*
1.75 markus 62: * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
63: * Default value is AF_UNSPEC means both IPv4 and IPv6.
64: */
65: int IPv4or6 = AF_UNSPEC;
66:
1.65 deraadt 67: /*
68: * Debug mode flag. This can be set on the command line. If debug
69: * mode is enabled, extra debugging output will be sent to the system
70: * log, the daemon will not go to background, and will exit after processing
71: * the first connection.
72: */
1.1 deraadt 73: int debug_flag = 0;
74:
75: /* Flag indicating that the daemon is being started from inetd. */
76: int inetd_flag = 0;
77:
1.47 markus 78: /* debug goes to stderr unless inetd_flag is set */
79: int log_stderr = 0;
80:
1.1 deraadt 81: /* argv[0] without path. */
82: char *av0;
83:
84: /* Saved arguments to main(). */
85: char **saved_argv;
86:
1.66 markus 87: /*
1.75 markus 88: * The sockets that the server is listening; this is used in the SIGHUP
89: * signal handler.
1.66 markus 90: */
1.75 markus 91: #define MAX_LISTEN_SOCKS 16
92: int listen_socks[MAX_LISTEN_SOCKS];
93: int num_listen_socks = 0;
1.1 deraadt 94:
1.66 markus 95: /*
96: * the client's version string, passed by sshd2 in compat mode. if != NULL,
97: * sshd will skip the version-number exchange
98: */
1.61 markus 99: char *client_version_string = NULL;
1.96 markus 100: char *server_version_string = NULL;
1.1 deraadt 101:
1.66 markus 102: /*
103: * Any really sensitive data in the application is contained in this
104: * structure. The idea is that this structure could be locked into memory so
105: * that the pages do not get written into swap. However, there are some
106: * problems. The private key contains BIGNUMs, and we do not (in principle)
107: * have access to the internals of them, and locking just the structure is
108: * not very useful. Currently, memory locking is not implemented.
109: */
1.64 markus 110: struct {
111: RSA *private_key; /* Private part of server key. */
112: RSA *host_key; /* Private part of host key. */
1.1 deraadt 113: } sensitive_data;
114:
1.66 markus 115: /*
116: * Flag indicating whether the current session key has been used. This flag
117: * is set whenever the key is used, and cleared when the key is regenerated.
118: */
1.1 deraadt 119: int key_used = 0;
120:
121: /* This is set to true when SIGHUP is received. */
122: int received_sighup = 0;
123:
124: /* Public side of the server key. This value is regenerated regularly with
125: the private key. */
1.2 provos 126: RSA *public_key;
1.1 deraadt 127:
1.96 markus 128: /* session identifier, used by RSA-auth */
129: unsigned char session_id[16];
130:
1.1 deraadt 131: /* Prototypes for various functions defined later in this file. */
1.96 markus 132: void do_ssh1_kex();
1.98 markus 133: void do_ssh2_kex();
1.87 markus 134:
135: /*
1.75 markus 136: * Close all listening sockets
137: */
138: void
139: close_listen_socks(void)
140: {
141: int i;
142: for (i = 0; i < num_listen_socks; i++)
143: close(listen_socks[i]);
144: num_listen_socks = -1;
145: }
146:
147: /*
1.65 deraadt 148: * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
149: * the effect is to reread the configuration file (and to regenerate
150: * the server key).
151: */
1.105 markus 152: void
1.64 markus 153: sighup_handler(int sig)
1.1 deraadt 154: {
1.64 markus 155: received_sighup = 1;
156: signal(SIGHUP, sighup_handler);
1.1 deraadt 157: }
158:
1.65 deraadt 159: /*
160: * Called from the main program after receiving SIGHUP.
161: * Restarts the server.
162: */
1.105 markus 163: void
1.64 markus 164: sighup_restart()
1.1 deraadt 165: {
1.64 markus 166: log("Received SIGHUP; restarting.");
1.75 markus 167: close_listen_socks();
1.64 markus 168: execv(saved_argv[0], saved_argv);
169: log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno));
170: exit(1);
1.1 deraadt 171: }
172:
1.65 deraadt 173: /*
174: * Generic signal handler for terminating signals in the master daemon.
175: * These close the listen socket; not closing it seems to cause "Address
176: * already in use" problems on some machines, which is inconvenient.
177: */
1.105 markus 178: void
1.64 markus 179: sigterm_handler(int sig)
1.1 deraadt 180: {
1.64 markus 181: log("Received signal %d; terminating.", sig);
1.75 markus 182: close_listen_socks();
1.64 markus 183: exit(255);
1.1 deraadt 184: }
185:
1.65 deraadt 186: /*
187: * SIGCHLD handler. This is called whenever a child dies. This will then
188: * reap any zombies left by exited c.
189: */
1.105 markus 190: void
1.64 markus 191: main_sigchld_handler(int sig)
1.1 deraadt 192: {
1.64 markus 193: int save_errno = errno;
194: int status;
1.60 deraadt 195:
1.64 markus 196: while (waitpid(-1, &status, WNOHANG) > 0)
197: ;
1.60 deraadt 198:
1.64 markus 199: signal(SIGCHLD, main_sigchld_handler);
200: errno = save_errno;
1.1 deraadt 201: }
202:
1.65 deraadt 203: /*
204: * Signal handler for the alarm after the login grace period has expired.
205: */
1.105 markus 206: void
1.64 markus 207: grace_alarm_handler(int sig)
1.1 deraadt 208: {
1.64 markus 209: /* Close the connection. */
210: packet_close();
211:
212: /* Log error and exit. */
213: fatal("Timeout before authentication for %s.", get_remote_ipaddr());
1.62 markus 214: }
215:
1.65 deraadt 216: /*
217: * Signal handler for the key regeneration alarm. Note that this
218: * alarm only occurs in the daemon waiting for connections, and it does not
219: * do anything with the private key or random state before forking.
220: * Thus there should be no concurrency control/asynchronous execution
221: * problems.
222: */
1.105 markus 223: void
1.64 markus 224: key_regeneration_alarm(int sig)
1.1 deraadt 225: {
1.64 markus 226: int save_errno = errno;
1.18 deraadt 227:
1.64 markus 228: /* Check if we should generate a new key. */
229: if (key_used) {
230: /* This should really be done in the background. */
231: log("Generating new %d bit RSA key.", options.server_key_bits);
232:
233: if (sensitive_data.private_key != NULL)
234: RSA_free(sensitive_data.private_key);
235: sensitive_data.private_key = RSA_new();
236:
237: if (public_key != NULL)
238: RSA_free(public_key);
239: public_key = RSA_new();
240:
241: rsa_generate_key(sensitive_data.private_key, public_key,
242: options.server_key_bits);
243: arc4random_stir();
244: key_used = 0;
245: log("RSA key generation complete.");
246: }
247: /* Reschedule the alarm. */
248: signal(SIGALRM, key_regeneration_alarm);
249: alarm(options.key_regeneration_time);
250: errno = save_errno;
1.1 deraadt 251: }
252:
1.98 markus 253: char *
254: chop(char *s)
255: {
1.105 markus 256: char *t = s;
257: while (*t) {
258: if(*t == '\n' || *t == '\r') {
259: *t = '\0';
260: return s;
261: }
262: t++;
263: }
264: return s;
1.98 markus 265:
266: }
267:
1.96 markus 268: void
269: sshd_exchange_identification(int sock_in, int sock_out)
270: {
1.102 markus 271: int i, mismatch;
1.96 markus 272: int remote_major, remote_minor;
1.102 markus 273: int major, minor;
1.96 markus 274: char *s;
275: char buf[256]; /* Must not be larger than remote_version. */
276: char remote_version[256]; /* Must be at least as big as buf. */
277:
1.103 markus 278: if ((options.protocol & SSH_PROTO_1) &&
279: (options.protocol & SSH_PROTO_2)) {
1.102 markus 280: major = PROTOCOL_MAJOR_1;
281: minor = 99;
282: } else if (options.protocol & SSH_PROTO_2) {
283: major = PROTOCOL_MAJOR_2;
284: minor = PROTOCOL_MINOR_2;
285: } else {
286: major = PROTOCOL_MAJOR_1;
287: minor = PROTOCOL_MINOR_1;
288: }
289: snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
1.96 markus 290: server_version_string = xstrdup(buf);
291:
292: if (client_version_string == NULL) {
293: /* Send our protocol version identification. */
294: if (atomicio(write, sock_out, server_version_string, strlen(server_version_string))
295: != strlen(server_version_string)) {
296: log("Could not write ident string to %s.", get_remote_ipaddr());
297: fatal_cleanup();
298: }
299:
300: /* Read other side\'s version identification. */
301: for (i = 0; i < sizeof(buf) - 1; i++) {
302: if (read(sock_in, &buf[i], 1) != 1) {
303: log("Did not receive ident string from %s.", get_remote_ipaddr());
304: fatal_cleanup();
305: }
306: if (buf[i] == '\r') {
307: buf[i] = '\n';
308: buf[i + 1] = 0;
309: continue;
310: }
311: if (buf[i] == '\n') {
312: /* buf[i] == '\n' */
313: buf[i + 1] = 0;
314: break;
315: }
316: }
317: buf[sizeof(buf) - 1] = 0;
318: client_version_string = xstrdup(buf);
319: }
320:
321: /*
322: * Check that the versions match. In future this might accept
323: * several versions and set appropriate flags to handle them.
324: */
325: if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
326: &remote_major, &remote_minor, remote_version) != 3) {
1.105 markus 327: s = "Protocol mismatch.\n";
1.96 markus 328: (void) atomicio(write, sock_out, s, strlen(s));
329: close(sock_in);
330: close(sock_out);
331: log("Bad protocol version identification '%.100s' from %s",
332: client_version_string, get_remote_ipaddr());
333: fatal_cleanup();
334: }
335: debug("Client protocol version %d.%d; client software version %.100s",
336: remote_major, remote_minor, remote_version);
337:
1.98 markus 338: compat_datafellows(remote_version);
339:
1.102 markus 340: mismatch = 0;
1.96 markus 341: switch(remote_major) {
342: case 1:
1.102 markus 343: if (!(options.protocol & SSH_PROTO_1)) {
344: mismatch = 1;
345: break;
346: }
1.96 markus 347: if (remote_minor < 3) {
348: packet_disconnect("Your ssh version is too old and"
349: "is no longer supported. Please install a newer version.");
350: } else if (remote_minor == 3) {
351: /* note that this disables agent-forwarding */
352: enable_compat13();
353: }
1.102 markus 354: if (remote_minor == 99) {
355: if (options.protocol & SSH_PROTO_2)
356: enable_compat20();
357: else
358: mismatch = 1;
359: }
360: break;
1.98 markus 361: case 2:
1.102 markus 362: if (options.protocol & SSH_PROTO_2) {
1.98 markus 363: enable_compat20();
364: break;
365: }
1.99 markus 366: /* FALLTHROUGH */
1.105 markus 367: default:
1.102 markus 368: mismatch = 1;
369: break;
370: }
371: chop(server_version_string);
372: chop(client_version_string);
373: debug("Local version string %.200s", server_version_string);
374:
375: if (mismatch) {
1.96 markus 376: s = "Protocol major versions differ.\n";
377: (void) atomicio(write, sock_out, s, strlen(s));
378: close(sock_in);
379: close(sock_out);
1.102 markus 380: log("Protocol major versions differ for %s: %.200s vs. %.200s",
381: get_remote_ipaddr(),
382: server_version_string, client_version_string);
1.96 markus 383: fatal_cleanup();
384: }
385: }
386:
1.65 deraadt 387: /*
388: * Main program for the daemon.
389: */
1.2 provos 390: int
391: main(int ac, char **av)
1.1 deraadt 392: {
1.64 markus 393: extern char *optarg;
394: extern int optind;
1.75 markus 395: int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1;
396: socklen_t fromlen;
1.64 markus 397: int silentrsa = 0;
1.75 markus 398: fd_set *fdset;
399: struct sockaddr_storage from;
1.64 markus 400: const char *remote_ip;
401: int remote_port;
402: char *comment;
403: FILE *f;
404: struct linger linger;
1.75 markus 405: struct addrinfo *ai;
406: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
407: int listen_sock, maxfd;
1.64 markus 408:
409: /* Save argv[0]. */
410: saved_argv = av;
411: if (strchr(av[0], '/'))
412: av0 = strrchr(av[0], '/') + 1;
413: else
414: av0 = av[0];
415:
416: /* Initialize configuration options to their default values. */
417: initialize_server_options(&options);
418:
419: /* Parse command-line arguments. */
1.102 markus 420: while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) {
1.64 markus 421: switch (opt) {
1.75 markus 422: case '4':
423: IPv4or6 = AF_INET;
424: break;
425: case '6':
426: IPv4or6 = AF_INET6;
427: break;
1.64 markus 428: case 'f':
429: config_file_name = optarg;
430: break;
431: case 'd':
432: debug_flag = 1;
433: options.log_level = SYSLOG_LEVEL_DEBUG;
434: break;
435: case 'i':
436: inetd_flag = 1;
437: break;
438: case 'Q':
439: silentrsa = 1;
440: break;
441: case 'q':
442: options.log_level = SYSLOG_LEVEL_QUIET;
443: break;
444: case 'b':
445: options.server_key_bits = atoi(optarg);
446: break;
447: case 'p':
1.75 markus 448: options.ports_from_cmdline = 1;
449: if (options.num_ports >= MAX_PORTS)
450: fatal("too many ports.\n");
451: options.ports[options.num_ports++] = atoi(optarg);
1.64 markus 452: break;
453: case 'g':
454: options.login_grace_time = atoi(optarg);
455: break;
456: case 'k':
457: options.key_regeneration_time = atoi(optarg);
458: break;
459: case 'h':
460: options.host_key_file = optarg;
461: break;
462: case 'V':
463: client_version_string = optarg;
464: /* only makes sense with inetd_flag, i.e. no listen() */
465: inetd_flag = 1;
466: break;
467: case '?':
468: default:
469: fprintf(stderr, "sshd version %s\n", SSH_VERSION);
470: fprintf(stderr, "Usage: %s [options]\n", av0);
471: fprintf(stderr, "Options:\n");
1.66 markus 472: fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
1.64 markus 473: fprintf(stderr, " -d Debugging mode\n");
474: fprintf(stderr, " -i Started from inetd\n");
475: fprintf(stderr, " -q Quiet (no logging)\n");
476: fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
477: fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
478: fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n");
479: fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
480: fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
1.75 markus 481: HOST_KEY_FILE);
482: fprintf(stderr, " -4 Use IPv4 only\n");
483: fprintf(stderr, " -6 Use IPv6 only\n");
1.64 markus 484: exit(1);
485: }
486: }
487:
1.75 markus 488: /*
489: * Force logging to stderr until we have loaded the private host
490: * key (unless started from inetd)
491: */
492: log_init(av0,
493: options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
494: options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
495: !inetd_flag);
496:
1.64 markus 497: /* check if RSA support exists */
498: if (rsa_alive() == 0) {
499: if (silentrsa == 0)
500: printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
501: log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
502: exit(1);
503: }
504: /* Read server configuration options from the configuration file. */
505: read_server_config(&options, config_file_name);
506:
507: /* Fill in default values for those options not explicitly set. */
508: fill_default_server_options(&options);
509:
510: /* Check certain values for sanity. */
511: if (options.server_key_bits < 512 ||
512: options.server_key_bits > 32768) {
513: fprintf(stderr, "Bad server key size.\n");
514: exit(1);
515: }
516: /* Check that there are no remaining arguments. */
517: if (optind < ac) {
518: fprintf(stderr, "Extra argument %s.\n", av[optind]);
519: exit(1);
520: }
521:
522: debug("sshd version %.100s", SSH_VERSION);
523:
524: sensitive_data.host_key = RSA_new();
525: errno = 0;
526: /* Load the host key. It must have empty passphrase. */
527: if (!load_private_key(options.host_key_file, "",
528: sensitive_data.host_key, &comment)) {
529: error("Could not load host key: %.200s: %.100s",
530: options.host_key_file, strerror(errno));
531: exit(1);
532: }
533: xfree(comment);
534:
535: /* Initialize the log (it is reinitialized below in case we
536: forked). */
537: if (debug_flag && !inetd_flag)
538: log_stderr = 1;
539: log_init(av0, options.log_level, options.log_facility, log_stderr);
540:
541: /* If not in debugging mode, and not started from inetd,
542: disconnect from the controlling terminal, and fork. The
543: original process exits. */
544: if (!debug_flag && !inetd_flag) {
1.1 deraadt 545: #ifdef TIOCNOTTY
1.64 markus 546: int fd;
1.1 deraadt 547: #endif /* TIOCNOTTY */
1.64 markus 548: if (daemon(0, 0) < 0)
549: fatal("daemon() failed: %.200s", strerror(errno));
550:
551: /* Disconnect from the controlling tty. */
1.1 deraadt 552: #ifdef TIOCNOTTY
1.64 markus 553: fd = open("/dev/tty", O_RDWR | O_NOCTTY);
554: if (fd >= 0) {
555: (void) ioctl(fd, TIOCNOTTY, NULL);
556: close(fd);
557: }
558: #endif /* TIOCNOTTY */
559: }
560: /* Reinitialize the log (because of the fork above). */
561: log_init(av0, options.log_level, options.log_facility, log_stderr);
562:
563: /* Check that server and host key lengths differ sufficiently.
564: This is necessary to make double encryption work with rsaref.
565: Oh, I hate software patents. I dont know if this can go? Niels */
566: if (options.server_key_bits >
567: BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
568: options.server_key_bits <
569: BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
570: options.server_key_bits =
571: BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
572: debug("Forcing server key to %d bits to make it differ from host key.",
573: options.server_key_bits);
1.1 deraadt 574: }
1.64 markus 575: /* Do not display messages to stdout in RSA code. */
576: rsa_set_verbose(0);
577:
578: /* Initialize the random number generator. */
579: arc4random_stir();
580:
581: /* Chdir to the root directory so that the current disk can be
582: unmounted if desired. */
583: chdir("/");
584:
585: /* Start listening for a socket, unless started from inetd. */
586: if (inetd_flag) {
587: int s1, s2;
588: s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
589: s2 = dup(s1);
590: sock_in = dup(0);
591: sock_out = dup(1);
592: /* We intentionally do not close the descriptors 0, 1, and 2
593: as our code for setting the descriptors won\'t work
594: if ttyfd happens to be one of those. */
595: debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
596:
597: public_key = RSA_new();
598: sensitive_data.private_key = RSA_new();
599:
1.102 markus 600: /* XXX check options.protocol */
1.64 markus 601: log("Generating %d bit RSA key.", options.server_key_bits);
602: rsa_generate_key(sensitive_data.private_key, public_key,
603: options.server_key_bits);
604: arc4random_stir();
605: log("RSA key generation complete.");
606: } else {
1.75 markus 607: for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
608: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
609: continue;
610: if (num_listen_socks >= MAX_LISTEN_SOCKS)
611: fatal("Too many listen sockets. "
612: "Enlarge MAX_LISTEN_SOCKS");
613: if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
614: ntop, sizeof(ntop), strport, sizeof(strport),
615: NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
616: error("getnameinfo failed");
617: continue;
618: }
619: /* Create socket for listening. */
620: listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
621: if (listen_sock < 0) {
622: /* kernel may not support ipv6 */
623: verbose("socket: %.100s", strerror(errno));
624: continue;
625: }
626: if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
627: error("listen_sock O_NONBLOCK: %s", strerror(errno));
628: close(listen_sock);
629: continue;
630: }
631: /*
632: * Set socket options. We try to make the port
633: * reusable and have it close as fast as possible
634: * without waiting in unnecessary wait states on
635: * close.
636: */
637: setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
638: (void *) &on, sizeof(on));
639: linger.l_onoff = 1;
640: linger.l_linger = 5;
641: setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
642: (void *) &linger, sizeof(linger));
643:
644: debug("Bind to port %s on %s.", strport, ntop);
645:
646: /* Bind the socket to the desired port. */
647: if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
648: error("Bind to port %s on %s failed: %.200s.",
649: strport, ntop, strerror(errno));
650: close(listen_sock);
651: continue;
652: }
653: listen_socks[num_listen_socks] = listen_sock;
654: num_listen_socks++;
655:
656: /* Start listening on the port. */
657: log("Server listening on %s port %s.", ntop, strport);
658: if (listen(listen_sock, 5) < 0)
659: fatal("listen: %.100s", strerror(errno));
660:
1.64 markus 661: }
1.75 markus 662: freeaddrinfo(options.listen_addrs);
663:
664: if (!num_listen_socks)
665: fatal("Cannot bind any address.");
666:
1.64 markus 667: if (!debug_flag) {
1.66 markus 668: /*
669: * Record our pid in /etc/sshd_pid to make it easier
670: * to kill the correct sshd. We don\'t want to do
671: * this before the bind above because the bind will
672: * fail if there already is a daemon, and this will
673: * overwrite any old pid in the file.
674: */
1.64 markus 675: f = fopen(SSH_DAEMON_PID_FILE, "w");
676: if (f) {
677: fprintf(f, "%u\n", (unsigned int) getpid());
678: fclose(f);
679: }
680: }
681:
682: public_key = RSA_new();
683: sensitive_data.private_key = RSA_new();
684:
685: log("Generating %d bit RSA key.", options.server_key_bits);
686: rsa_generate_key(sensitive_data.private_key, public_key,
687: options.server_key_bits);
688: arc4random_stir();
689: log("RSA key generation complete.");
690:
691: /* Schedule server key regeneration alarm. */
692: signal(SIGALRM, key_regeneration_alarm);
693: alarm(options.key_regeneration_time);
694:
695: /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
696: signal(SIGHUP, sighup_handler);
697: signal(SIGTERM, sigterm_handler);
698: signal(SIGQUIT, sigterm_handler);
699:
700: /* Arrange SIGCHLD to be caught. */
701: signal(SIGCHLD, main_sigchld_handler);
702:
1.75 markus 703: /* setup fd set for listen */
704: maxfd = 0;
705: for (i = 0; i < num_listen_socks; i++)
706: if (listen_socks[i] > maxfd)
707: maxfd = listen_socks[i];
1.105 markus 708: fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
709: fdset = (fd_set *)xmalloc(fdsetsz);
1.75 markus 710:
1.66 markus 711: /*
712: * Stay listening for connections until the system crashes or
713: * the daemon is killed with a signal.
714: */
1.64 markus 715: for (;;) {
716: if (received_sighup)
717: sighup_restart();
1.75 markus 718: /* Wait in select until there is a connection. */
719: memset(fdset, 0, fdsetsz);
720: for (i = 0; i < num_listen_socks; i++)
721: FD_SET(listen_socks[i], fdset);
722: if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) {
723: if (errno != EINTR)
724: error("select: %.100s", strerror(errno));
725: continue;
726: }
727: for (i = 0; i < num_listen_socks; i++) {
728: if (!FD_ISSET(listen_socks[i], fdset))
1.70 provos 729: continue;
1.75 markus 730: fromlen = sizeof(from);
731: newsock = accept(listen_socks[i], (struct sockaddr *)&from,
732: &fromlen);
733: if (newsock < 0) {
734: if (errno != EINTR && errno != EWOULDBLOCK)
735: error("accept: %.100s", strerror(errno));
736: continue;
1.70 provos 737: }
1.75 markus 738: if (fcntl(newsock, F_SETFL, 0) < 0) {
739: error("newsock del O_NONBLOCK: %s", strerror(errno));
1.64 markus 740: continue;
741: }
1.66 markus 742: /*
743: * Got connection. Fork a child to handle it, unless
744: * we are in debugging mode.
745: */
1.64 markus 746: if (debug_flag) {
1.66 markus 747: /*
748: * In debugging mode. Close the listening
749: * socket, and start processing the
750: * connection without forking.
751: */
1.64 markus 752: debug("Server will not fork when running in debugging mode.");
1.75 markus 753: close_listen_socks();
1.64 markus 754: sock_in = newsock;
755: sock_out = newsock;
756: pid = getpid();
757: break;
758: } else {
1.66 markus 759: /*
760: * Normal production daemon. Fork, and have
761: * the child process the connection. The
762: * parent continues listening.
763: */
1.64 markus 764: if ((pid = fork()) == 0) {
1.66 markus 765: /*
766: * Child. Close the listening socket, and start using the
767: * accepted socket. Reinitialize logging (since our pid has
768: * changed). We break out of the loop to handle the connection.
769: */
1.75 markus 770: close_listen_socks();
1.64 markus 771: sock_in = newsock;
772: sock_out = newsock;
773: log_init(av0, options.log_level, options.log_facility, log_stderr);
774: break;
775: }
776: }
777:
778: /* Parent. Stay in the loop. */
779: if (pid < 0)
780: error("fork: %.100s", strerror(errno));
781: else
782: debug("Forked child %d.", pid);
1.1 deraadt 783:
1.64 markus 784: /* Mark that the key has been used (it was "given" to the child). */
785: key_used = 1;
1.1 deraadt 786:
1.64 markus 787: arc4random_stir();
1.1 deraadt 788:
1.64 markus 789: /* Close the new socket (the child is now taking care of it). */
790: close(newsock);
1.75 markus 791: } /* for (i = 0; i < num_listen_socks; i++) */
792: /* child process check (or debug mode) */
793: if (num_listen_socks < 0)
794: break;
1.64 markus 795: }
1.1 deraadt 796: }
797:
1.64 markus 798: /* This is the child processing a new connection. */
799:
1.66 markus 800: /*
801: * Disable the key regeneration alarm. We will not regenerate the
802: * key since we are no longer in a position to give it to anyone. We
803: * will not restart on SIGHUP since it no longer makes sense.
804: */
1.64 markus 805: alarm(0);
806: signal(SIGALRM, SIG_DFL);
807: signal(SIGHUP, SIG_DFL);
808: signal(SIGTERM, SIG_DFL);
809: signal(SIGQUIT, SIG_DFL);
810: signal(SIGCHLD, SIG_DFL);
811:
1.66 markus 812: /*
813: * Set socket options for the connection. We want the socket to
814: * close as fast as possible without waiting for anything. If the
815: * connection is not a socket, these will do nothing.
816: */
817: /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
1.64 markus 818: linger.l_onoff = 1;
819: linger.l_linger = 5;
820: setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
821:
1.66 markus 822: /*
823: * Register our connection. This turns encryption off because we do
824: * not have a key.
825: */
1.64 markus 826: packet_set_connection(sock_in, sock_out);
1.1 deraadt 827:
1.64 markus 828: remote_port = get_remote_port();
829: remote_ip = get_remote_ipaddr();
1.52 markus 830:
1.64 markus 831: /* Check whether logins are denied from this host. */
1.37 dugsong 832: #ifdef LIBWRAP
1.75 markus 833: /* XXX LIBWRAP noes not know about IPv6 */
1.64 markus 834: {
835: struct request_info req;
1.37 dugsong 836:
1.64 markus 837: request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
838: fromhost(&req);
1.37 dugsong 839:
1.64 markus 840: if (!hosts_access(&req)) {
841: close(sock_in);
842: close(sock_out);
843: refuse(&req);
844: }
1.75 markus 845: /*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
1.64 markus 846: }
1.75 markus 847: #endif /* LIBWRAP */
1.64 markus 848: /* Log the connection. */
849: verbose("Connection from %.500s port %d", remote_ip, remote_port);
1.1 deraadt 850:
1.66 markus 851: /*
852: * We don\'t want to listen forever unless the other side
853: * successfully authenticates itself. So we set up an alarm which is
854: * cleared after successful authentication. A limit of zero
855: * indicates no limit. Note that we don\'t set the alarm in debugging
856: * mode; it is just annoying to have the server exit just when you
857: * are about to discover the bug.
858: */
1.64 markus 859: signal(SIGALRM, grace_alarm_handler);
860: if (!debug_flag)
861: alarm(options.login_grace_time);
862:
1.96 markus 863: sshd_exchange_identification(sock_in, sock_out);
1.66 markus 864: /*
865: * Check that the connection comes from a privileged port. Rhosts-
866: * and Rhosts-RSA-Authentication only make sense from priviledged
867: * programs. Of course, if the intruder has root access on his local
868: * machine, he can connect from any port. So do not use these
869: * authentication methods from machines that you do not trust.
870: */
1.64 markus 871: if (remote_port >= IPPORT_RESERVED ||
872: remote_port < IPPORT_RESERVED / 2) {
873: options.rhosts_authentication = 0;
874: options.rhosts_rsa_authentication = 0;
875: }
1.76 markus 876: #ifdef KRB4
877: if (!packet_connection_is_ipv4() &&
878: options.kerberos_authentication) {
879: debug("Kerberos Authentication disabled, only available for IPv4.");
880: options.kerberos_authentication = 0;
881: }
882: #endif /* KRB4 */
883:
1.64 markus 884: packet_set_nonblocking();
1.1 deraadt 885:
1.77 markus 886: /* perform the key exchange */
887: /* authenticate user and start session */
1.98 markus 888: if (compat20) {
889: do_ssh2_kex();
890: do_authentication2();
891: } else {
892: do_ssh1_kex();
893: do_authentication();
894: }
1.1 deraadt 895:
896: #ifdef KRB4
1.64 markus 897: /* Cleanup user's ticket cache file. */
898: if (options.kerberos_ticket_cleanup)
899: (void) dest_tkt();
1.1 deraadt 900: #endif /* KRB4 */
901:
1.64 markus 902: /* The connection has been terminated. */
903: verbose("Closing connection to %.100s", remote_ip);
904: packet_close();
905: exit(0);
1.1 deraadt 906: }
907:
1.65 deraadt 908: /*
1.77 markus 909: * SSH1 key exchange
1.65 deraadt 910: */
1.52 markus 911: void
1.96 markus 912: do_ssh1_kex()
1.1 deraadt 913: {
1.64 markus 914: int i, len;
1.77 markus 915: int plen, slen;
1.64 markus 916: BIGNUM *session_key_int;
917: unsigned char session_key[SSH_SESSION_KEY_LENGTH];
1.77 markus 918: unsigned char cookie[8];
1.64 markus 919: unsigned int cipher_type, auth_mask, protocol_flags;
920: u_int32_t rand = 0;
921:
1.66 markus 922: /*
923: * Generate check bytes that the client must send back in the user
924: * packet in order for it to be accepted; this is used to defy ip
925: * spoofing attacks. Note that this only works against somebody
926: * doing IP spoofing from a remote machine; any machine on the local
927: * network can still see outgoing packets and catch the random
928: * cookie. This only affects rhosts authentication, and this is one
929: * of the reasons why it is inherently insecure.
930: */
1.64 markus 931: for (i = 0; i < 8; i++) {
932: if (i % 4 == 0)
933: rand = arc4random();
1.77 markus 934: cookie[i] = rand & 0xff;
1.64 markus 935: rand >>= 8;
936: }
937:
1.66 markus 938: /*
939: * Send our public key. We include in the packet 64 bits of random
940: * data that must be matched in the reply in order to prevent IP
941: * spoofing.
942: */
1.64 markus 943: packet_start(SSH_SMSG_PUBLIC_KEY);
944: for (i = 0; i < 8; i++)
1.77 markus 945: packet_put_char(cookie[i]);
1.64 markus 946:
947: /* Store our public server RSA key. */
948: packet_put_int(BN_num_bits(public_key->n));
949: packet_put_bignum(public_key->e);
950: packet_put_bignum(public_key->n);
951:
952: /* Store our public host RSA key. */
953: packet_put_int(BN_num_bits(sensitive_data.host_key->n));
954: packet_put_bignum(sensitive_data.host_key->e);
955: packet_put_bignum(sensitive_data.host_key->n);
956:
957: /* Put protocol flags. */
958: packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
959:
960: /* Declare which ciphers we support. */
1.97 markus 961: packet_put_int(cipher_mask1());
1.64 markus 962:
963: /* Declare supported authentication types. */
964: auth_mask = 0;
965: if (options.rhosts_authentication)
966: auth_mask |= 1 << SSH_AUTH_RHOSTS;
967: if (options.rhosts_rsa_authentication)
968: auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
969: if (options.rsa_authentication)
970: auth_mask |= 1 << SSH_AUTH_RSA;
1.1 deraadt 971: #ifdef KRB4
1.64 markus 972: if (options.kerberos_authentication)
973: auth_mask |= 1 << SSH_AUTH_KERBEROS;
1.1 deraadt 974: #endif
1.5 dugsong 975: #ifdef AFS
1.64 markus 976: if (options.kerberos_tgt_passing)
977: auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
978: if (options.afs_token_passing)
979: auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
1.1 deraadt 980: #endif
1.63 markus 981: #ifdef SKEY
1.64 markus 982: if (options.skey_authentication == 1)
983: auth_mask |= 1 << SSH_AUTH_TIS;
1.63 markus 984: #endif
1.64 markus 985: if (options.password_authentication)
986: auth_mask |= 1 << SSH_AUTH_PASSWORD;
987: packet_put_int(auth_mask);
988:
989: /* Send the packet and wait for it to be sent. */
990: packet_send();
991: packet_write_wait();
992:
993: debug("Sent %d bit public key and %d bit host key.",
994: BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
995:
996: /* Read clients reply (cipher type and session key). */
997: packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
998:
1.69 markus 999: /* Get cipher type and check whether we accept this. */
1.64 markus 1000: cipher_type = packet_get_char();
1.69 markus 1001:
1.105 markus 1002: if (!(cipher_mask() & (1 << cipher_type)))
1.69 markus 1003: packet_disconnect("Warning: client selects unsupported cipher.");
1.64 markus 1004:
1005: /* Get check bytes from the packet. These must match those we
1006: sent earlier with the public key packet. */
1007: for (i = 0; i < 8; i++)
1.77 markus 1008: if (cookie[i] != packet_get_char())
1.64 markus 1009: packet_disconnect("IP Spoofing check bytes do not match.");
1010:
1011: debug("Encryption type: %.200s", cipher_name(cipher_type));
1012:
1013: /* Get the encrypted integer. */
1014: session_key_int = BN_new();
1015: packet_get_bignum(session_key_int, &slen);
1016:
1017: protocol_flags = packet_get_int();
1018: packet_set_protocol_flags(protocol_flags);
1019:
1020: packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
1021:
1.66 markus 1022: /*
1023: * Decrypt it using our private server key and private host key (key
1024: * with larger modulus first).
1025: */
1.64 markus 1026: if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
1027: /* Private key has bigger modulus. */
1028: if (BN_num_bits(sensitive_data.private_key->n) <
1029: BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
1030: fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1031: get_remote_ipaddr(),
1032: BN_num_bits(sensitive_data.private_key->n),
1033: BN_num_bits(sensitive_data.host_key->n),
1034: SSH_KEY_BITS_RESERVED);
1035: }
1036: rsa_private_decrypt(session_key_int, session_key_int,
1037: sensitive_data.private_key);
1038: rsa_private_decrypt(session_key_int, session_key_int,
1039: sensitive_data.host_key);
1040: } else {
1041: /* Host key has bigger modulus (or they are equal). */
1042: if (BN_num_bits(sensitive_data.host_key->n) <
1043: BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
1044: fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
1045: get_remote_ipaddr(),
1046: BN_num_bits(sensitive_data.host_key->n),
1047: BN_num_bits(sensitive_data.private_key->n),
1048: SSH_KEY_BITS_RESERVED);
1049: }
1050: rsa_private_decrypt(session_key_int, session_key_int,
1051: sensitive_data.host_key);
1052: rsa_private_decrypt(session_key_int, session_key_int,
1053: sensitive_data.private_key);
1054: }
1055:
1.77 markus 1056: compute_session_id(session_id, cookie,
1.64 markus 1057: sensitive_data.host_key->n,
1058: sensitive_data.private_key->n);
1059:
1.77 markus 1060: /* Destroy the private and public keys. They will no longer be needed. */
1061: RSA_free(public_key);
1062: RSA_free(sensitive_data.private_key);
1063: RSA_free(sensitive_data.host_key);
1064:
1.66 markus 1065: /*
1066: * Extract session key from the decrypted integer. The key is in the
1067: * least significant 256 bits of the integer; the first byte of the
1068: * key is in the highest bits.
1069: */
1.64 markus 1070: BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1071: len = BN_num_bytes(session_key_int);
1072: if (len < 0 || len > sizeof(session_key))
1073: fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
1074: get_remote_ipaddr(),
1075: len, sizeof(session_key));
1076: memset(session_key, 0, sizeof(session_key));
1077: BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
1078:
1.77 markus 1079: /* Destroy the decrypted integer. It is no longer needed. */
1080: BN_clear_free(session_key_int);
1081:
1.64 markus 1082: /* Xor the first 16 bytes of the session key with the session id. */
1083: for (i = 0; i < 16; i++)
1084: session_key[i] ^= session_id[i];
1085:
1086: /* Set the session key. From this on all communications will be encrypted. */
1087: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1088:
1089: /* Destroy our copy of the session key. It is no longer needed. */
1090: memset(session_key, 0, sizeof(session_key));
1091:
1092: debug("Received session key; encryption turned on.");
1093:
1094: /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1095: packet_start(SSH_SMSG_SUCCESS);
1096: packet_send();
1097: packet_write_wait();
1.98 markus 1098: }
1099:
1100: /*
1101: * SSH2 key exchange: diffie-hellman-group1-sha1
1102: */
1103: void
1104: do_ssh2_kex()
1105: {
1106: Buffer *server_kexinit;
1107: Buffer *client_kexinit;
1108: int payload_len, dlen;
1109: int slen;
1110: unsigned int klen, kout;
1111: char *ptr;
1112: unsigned char *signature = NULL;
1113: unsigned char *server_host_key_blob = NULL;
1114: unsigned int sbloblen;
1115: DH *dh;
1116: BIGNUM *dh_client_pub = 0;
1117: BIGNUM *shared_secret = 0;
1118: int i;
1119: unsigned char *kbuf;
1120: unsigned char *hash;
1121: Kex *kex;
1122: Key *server_host_key;
1123: char *cprop[PROPOSAL_MAX];
1124: char *sprop[PROPOSAL_MAX];
1125:
1126: /* KEXINIT */
1.102 markus 1127:
1128: if (options.ciphers != NULL) {
1.105 markus 1129: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1.102 markus 1130: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1131: }
1.98 markus 1132:
1133: debug("Sending KEX init.");
1134:
1135: for (i = 0; i < PROPOSAL_MAX; i++)
1136: sprop[i] = xstrdup(myproposal[i]);
1137: server_kexinit = kex_init(sprop);
1138: packet_start(SSH2_MSG_KEXINIT);
1139: packet_put_raw(buffer_ptr(server_kexinit), buffer_len(server_kexinit));
1140: packet_send();
1141: packet_write_wait();
1142:
1143: debug("done");
1144:
1145: packet_read_expect(&payload_len, SSH2_MSG_KEXINIT);
1146:
1147: /*
1148: * save raw KEXINIT payload in buffer. this is used during
1149: * computation of the session_id and the session keys.
1150: */
1151: client_kexinit = xmalloc(sizeof(*client_kexinit));
1152: buffer_init(client_kexinit);
1153: ptr = packet_get_raw(&payload_len);
1154: buffer_append(client_kexinit, ptr, payload_len);
1155:
1156: /* skip cookie */
1157: for (i = 0; i < 16; i++)
1158: (void) packet_get_char();
1159: /* save kex init proposal strings */
1160: for (i = 0; i < PROPOSAL_MAX; i++) {
1161: cprop[i] = packet_get_string(NULL);
1162: debug("got kexinit string: %s", cprop[i]);
1163: }
1164:
1165: i = (int) packet_get_char();
1166: debug("first kex follow == %d", i);
1167: i = packet_get_int();
1168: debug("reserved == %d", i);
1169:
1170: debug("done read kexinit");
1171: kex = kex_choose_conf(cprop, sprop, 1);
1172:
1173: /* KEXDH */
1174:
1175: debug("Wait SSH2_MSG_KEXDH_INIT.");
1176: packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
1177:
1178: /* key, cert */
1179: dh_client_pub = BN_new();
1180: if (dh_client_pub == NULL)
1181: fatal("dh_client_pub == NULL");
1182: packet_get_bignum2(dh_client_pub, &dlen);
1183:
1184: #ifdef DEBUG_KEXDH
1185: fprintf(stderr, "\ndh_client_pub= ");
1186: bignum_print(dh_client_pub);
1187: fprintf(stderr, "\n");
1188: debug("bits %d", BN_num_bits(dh_client_pub));
1189: #endif
1190:
1191: /* generate DH key */
1.101 markus 1192: dh = dh_new_group1(); /* XXX depends on 'kex' */
1.98 markus 1193:
1194: #ifdef DEBUG_KEXDH
1195: fprintf(stderr, "\np= ");
1196: bignum_print(dh->p);
1197: fprintf(stderr, "\ng= ");
1198: bignum_print(dh->g);
1199: fprintf(stderr, "\npub= ");
1200: bignum_print(dh->pub_key);
1201: fprintf(stderr, "\n");
1202: #endif
1.101 markus 1203: if (!dh_pub_is_valid(dh, dh_client_pub))
1204: packet_disconnect("bad client public DH value");
1.98 markus 1205:
1206: klen = DH_size(dh);
1207: kbuf = xmalloc(klen);
1208: kout = DH_compute_key(kbuf, dh_client_pub, dh);
1209:
1210: #ifdef DEBUG_KEXDH
1211: debug("shared secret: len %d/%d", klen, kout);
1212: fprintf(stderr, "shared secret == ");
1213: for (i = 0; i< kout; i++)
1214: fprintf(stderr, "%02x", (kbuf[i])&0xff);
1215: fprintf(stderr, "\n");
1216: #endif
1217: shared_secret = BN_new();
1218:
1219: BN_bin2bn(kbuf, kout, shared_secret);
1220: memset(kbuf, 0, klen);
1221: xfree(kbuf);
1222:
1223: server_host_key = dsa_get_serverkey(options.dsa_key_file);
1224: dsa_make_serverkey_blob(server_host_key, &server_host_key_blob, &sbloblen);
1225:
1226: /* calc H */ /* XXX depends on 'kex' */
1227: hash = kex_hash(
1228: client_version_string,
1229: server_version_string,
1230: buffer_ptr(client_kexinit), buffer_len(client_kexinit),
1231: buffer_ptr(server_kexinit), buffer_len(server_kexinit),
1232: (char *)server_host_key_blob, sbloblen,
1233: dh_client_pub,
1234: dh->pub_key,
1235: shared_secret
1236: );
1237: buffer_free(client_kexinit);
1238: buffer_free(server_kexinit);
1239: xfree(client_kexinit);
1240: xfree(server_kexinit);
1241: #ifdef DEBUG_KEXDH
1.105 markus 1242: fprintf(stderr, "hash == ");
1243: for (i = 0; i< 20; i++)
1244: fprintf(stderr, "%02x", (hash[i])&0xff);
1245: fprintf(stderr, "\n");
1.98 markus 1246: #endif
1247: /* sign H */
1248: dsa_sign(server_host_key, &signature, &slen, hash, 20);
1249: /* hashlen depends on KEX */
1250: key_free(server_host_key);
1251:
1252: /* send server hostkey, DH pubkey 'f' and singed H */
1253: packet_start(SSH2_MSG_KEXDH_REPLY);
1254: packet_put_string((char *)server_host_key_blob, sbloblen);
1255: packet_put_bignum2(dh->pub_key); // f
1256: packet_put_string((char *)signature, slen);
1257: packet_send();
1.106 ! markus 1258: xfree(signature);
1.98 markus 1259: packet_write_wait();
1260:
1261: kex_derive_keys(kex, hash, shared_secret);
1262: packet_set_kex(kex);
1263:
1264: /* have keys, free DH */
1265: DH_free(dh);
1266:
1267: debug("send SSH2_MSG_NEWKEYS.");
1268: packet_start(SSH2_MSG_NEWKEYS);
1269: packet_send();
1270: packet_write_wait();
1271: debug("done: send SSH2_MSG_NEWKEYS.");
1272:
1273: debug("Wait SSH2_MSG_NEWKEYS.");
1274: packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
1275: debug("GOT SSH2_MSG_NEWKEYS.");
1276:
1.100 markus 1277: #ifdef DEBUG_KEXDH
1.98 markus 1278: /* send 1st encrypted/maced/compressed message */
1279: packet_start(SSH2_MSG_IGNORE);
1280: packet_put_cstring("markus");
1281: packet_send();
1282: packet_write_wait();
1.100 markus 1283: #endif
1.98 markus 1284: debug("done: KEX2.");
1.1 deraadt 1285: }
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