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1/*
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: Sat Mar 18 22:15:47 1995 ylo
6 * Code to connect to a remote host, and to perform the client side of the
7 * login (authentication) dialog.
8 */
9
10#include "includes.h"
11RCSID("$OpenBSD: sshconnect.c,v 1.76 2000/06/17 20:30:10 markus Exp $");
12
13#include <openssl/bn.h>
14#include <openssl/dsa.h>
15#include <openssl/rsa.h>
16
17#include "xmalloc.h"
18#include "rsa.h"
19#include "ssh.h"
20#include "buffer.h"
21#include "packet.h"
22#include "uidswap.h"
23#include "compat.h"
24#include "readconf.h"
25#include "key.h"
26#include "sshconnect.h"
27#include "hostfile.h"
28
29char *client_version_string = NULL;
30char *server_version_string = NULL;
31
32extern Options options;
33#ifdef HAVE___PROGNAME
34extern char *__progname;
35#else /* HAVE___PROGNAME */
36static const char *__progname = "ssh";
37#endif /* HAVE___PROGNAME */
38
39/*
40 * Connect to the given ssh server using a proxy command.
41 */
42int
43ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
44 const char *proxy_command)
45{
46 Buffer command;
47 const char *cp;
48 char *command_string;
49 int pin[2], pout[2];
50 pid_t pid;
51 char strport[NI_MAXSERV];
52
53 /* Convert the port number into a string. */
54 snprintf(strport, sizeof strport, "%hu", port);
55
56 /* Build the final command string in the buffer by making the
57 appropriate substitutions to the given proxy command. */
58 buffer_init(&command);
59 for (cp = proxy_command; *cp; cp++) {
60 if (cp[0] == '%' && cp[1] == '%') {
61 buffer_append(&command, "%", 1);
62 cp++;
63 continue;
64 }
65 if (cp[0] == '%' && cp[1] == 'h') {
66 buffer_append(&command, host, strlen(host));
67 cp++;
68 continue;
69 }
70 if (cp[0] == '%' && cp[1] == 'p') {
71 buffer_append(&command, strport, strlen(strport));
72 cp++;
73 continue;
74 }
75 buffer_append(&command, cp, 1);
76 }
77 buffer_append(&command, "\0", 1);
78
79 /* Get the final command string. */
80 command_string = buffer_ptr(&command);
81
82 /* Create pipes for communicating with the proxy. */
83 if (pipe(pin) < 0 || pipe(pout) < 0)
84 fatal("Could not create pipes to communicate with the proxy: %.100s",
85 strerror(errno));
86
87 debug("Executing proxy command: %.500s", command_string);
88
89 /* Fork and execute the proxy command. */
90 if ((pid = fork()) == 0) {
91 char *argv[10];
92
93 /* Child. Permanently give up superuser privileges. */
94 permanently_set_uid(original_real_uid);
95
96 /* Redirect stdin and stdout. */
97 close(pin[1]);
98 if (pin[0] != 0) {
99 if (dup2(pin[0], 0) < 0)
100 perror("dup2 stdin");
101 close(pin[0]);
102 }
103 close(pout[0]);
104 if (dup2(pout[1], 1) < 0)
105 perror("dup2 stdout");
106 /* Cannot be 1 because pin allocated two descriptors. */
107 close(pout[1]);
108
109 /* Stderr is left as it is so that error messages get
110 printed on the user's terminal. */
111 argv[0] = _PATH_BSHELL;
112 argv[1] = "-c";
113 argv[2] = command_string;
114 argv[3] = NULL;
115
116 /* Execute the proxy command. Note that we gave up any
117 extra privileges above. */
118 execv(_PATH_BSHELL, argv);
119 perror(_PATH_BSHELL);
120 exit(1);
121 }
122 /* Parent. */
123 if (pid < 0)
124 fatal("fork failed: %.100s", strerror(errno));
125
126 /* Close child side of the descriptors. */
127 close(pin[0]);
128 close(pout[1]);
129
130 /* Free the command name. */
131 buffer_free(&command);
132
133 /* Set the connection file descriptors. */
134 packet_set_connection(pout[0], pin[1]);
135
136 return 1;
137}
138
139/*
140 * Creates a (possibly privileged) socket for use as the ssh connection.
141 */
142int
143ssh_create_socket(uid_t original_real_uid, int privileged, int family)
144{
145 int sock;
146
147 /*
148 * If we are running as root and want to connect to a privileged
149 * port, bind our own socket to a privileged port.
150 */
151 if (privileged) {
152 int p = IPPORT_RESERVED - 1;
153 sock = rresvport_af(&p, family);
154 if (sock < 0)
155 error("rresvport: af=%d %.100s", family, strerror(errno));
156 else
157 debug("Allocated local port %d.", p);
158 } else {
159 /*
160 * Just create an ordinary socket on arbitrary port. We use
161 * the user's uid to create the socket.
162 */
163 temporarily_use_uid(original_real_uid);
164 sock = socket(family, SOCK_STREAM, 0);
165 if (sock < 0)
166 error("socket: %.100s", strerror(errno));
167 restore_uid();
168 }
169 return sock;
170}
171
172/*
173 * Opens a TCP/IP connection to the remote server on the given host.
174 * The address of the remote host will be returned in hostaddr.
175 * If port is 0, the default port will be used. If anonymous is zero,
176 * a privileged port will be allocated to make the connection.
177 * This requires super-user privileges if anonymous is false.
178 * Connection_attempts specifies the maximum number of tries (one per
179 * second). If proxy_command is non-NULL, it specifies the command (with %h
180 * and %p substituted for host and port, respectively) to use to contact
181 * the daemon.
182 */
183extern int reverse_fun;
184
185int
186ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
187 u_short port, int connection_attempts,
188 int anonymous, uid_t original_real_uid,
189 const char *proxy_command)
190{
191 int sock = -1, attempt;
192 struct servent *sp;
193 struct addrinfo hints, *ai, *aitop;
194 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
195 int gaierr;
196 struct linger linger;
197
198 debug("ssh_connect: getuid %d geteuid %d anon %d",
199 (int) getuid(), (int) geteuid(), anonymous);
200
201 /* Get default port if port has not been set. */
202 if (port == 0) {
203 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
204 if (sp)
205 port = ntohs(sp->s_port);
206 else
207 port = SSH_DEFAULT_PORT;
208 }
209 /* If a proxy command is given, connect using it. */
210 if (proxy_command != NULL && !reverse_fun)
211 return ssh_proxy_connect(host, port, original_real_uid, proxy_command);
212
213 /* No proxy command. */
214
215 memset(&hints, 0, sizeof(hints));
216 hints.ai_family = IPv4or6;
217 hints.ai_socktype = SOCK_STREAM;
218 snprintf(strport, sizeof strport, "%d", port);
219 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
220 fatal("%s: %.100s: %s", __progname, host,
221 gai_strerror(gaierr));
222
223 /* Lets have reverse fun, in this case client acts as server
224 */
225 if (reverse_fun) {
226 int s, one = 1, size_aa = sizeof(struct sockaddr);
227 struct addrinfo *aid;
228 struct sockaddr aa;
229
230 if ((gaierr = getaddrinfo("127.0.0.1", strport, &hints, &aid)) < 0) {
231 fprintf(stderr, "getaddrinfo (during reverse fun): %s\n", gai_strerror(gaierr));
232 exit(gaierr);
233 }
234
235 /* IPv4 */
236 if (aid->ai_family == PF_INET) {
237 ((struct sockaddr_in*)(aid->ai_addr))->sin_addr.s_addr = INADDR_ANY;
238 /* IPv6? :) */
239 }
240#ifdef HAVE_STRUCT_IN6_ADDR
241 else {
242 ((struct sockaddr_in6*)(aid->ai_addr))->sin6_addr = in6addr_any;
243 }
244#endif
245
246
247 if ((s = socket(aid->ai_family, SOCK_STREAM, 0)) < 0) {
248 perror("socket (during reverse fun)");
249 exit(errno);
250 }
251
252 if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0) {
253 perror("setsockopt (during reverse fun)\n");
254 exit(errno);
255 }
256
257 printf("Reverse fun: binding to port %s\n", strport);
258 if (bind(s, (struct sockaddr*)(aid->ai_addr), sizeof(struct sockaddr)) < 0) {
259 perror("bind (during reverse fun)");
260 exit(errno);
261 }
262
263 if (listen(s, 1) < 0) {
264 perror("listen (during reverse fun)");
265 exit(errno);
266 }
267
268 if ((sock = accept(s, &aa, &size_aa)) < 0) {
269 perror("accept (during reverse fun)");
270 exit(errno);
271 }
272 memcpy(hostaddr, &aa, size_aa);
273
274 /* sorry, sorry, sorry! */
275 goto start_fun;
276 }
277
278 /*
279 * Try to connect several times. On some machines, the first time
280 * will sometimes fail. In general socket code appears to behave
281 * quite magically on many machines.
282 */
283 for (attempt = 0; attempt < connection_attempts; attempt++) {
284 if (attempt > 0)
285 debug("Trying again...");
286
287 /* Loop through addresses for this host, and try each one in
288 sequence until the connection succeeds. */
289 for (ai = aitop; ai; ai = ai->ai_next) {
290 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
291 continue;
292 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
293 ntop, sizeof(ntop), strport, sizeof(strport),
294 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
295 error("ssh_connect: getnameinfo failed");
296 continue;
297 }
298 debug("Connecting to %.200s [%.100s] port %s.",
299 host, ntop, strport);
300
301 /* Create a socket for connecting. */
302 sock = ssh_create_socket(original_real_uid,
303 !anonymous && geteuid() == 0 && port < IPPORT_RESERVED,
304 ai->ai_family);
305 if (sock < 0)
306 continue;
307
308 /* Connect to the host. We use the user's uid in the
309 * hope that it will help with tcp_wrappers showing
310 * the remote uid as root.
311 */
312 temporarily_use_uid(original_real_uid);
313 if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
314 /* Successful connection. */
315 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
316 restore_uid();
317 break;
318 } else {
319 debug("connect: %.100s", strerror(errno));
320 restore_uid();
321 /*
322 * Close the failed socket; there appear to
323 * be some problems when reusing a socket for
324 * which connect() has already returned an
325 * error.
326 */
327 shutdown(sock, SHUT_RDWR);
328 close(sock);
329 }
330 }
331 if (ai)
332 break; /* Successful connection. */
333
334 /* Sleep a moment before retrying. */
335 sleep(1);
336 }
337
338 freeaddrinfo(aitop);
339
340 /* Return failure if we didn't get a successful connection. */
341 if (attempt >= connection_attempts)
342 return 0;
343
344start_fun:
345 debug("Connection established.");
346
347 /*
348 * Set socket options. We would like the socket to disappear as soon
349 * as it has been closed for whatever reason.
350 */
351 /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
352 linger.l_onoff = 1;
353 linger.l_linger = 5;
354 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
355
356 /* Set the connection. */
357 packet_set_connection(sock, sock);
358
359 return 1;
360}
361
362/*
363 * Waits for the server identification string, and sends our own
364 * identification string.
365 */
366void
367ssh_exchange_identification()
368{
369 char buf[256], remote_version[256]; /* must be same size! */
370 int remote_major, remote_minor, i, mismatch;
371 int connection_in = packet_get_connection_in();
372 int connection_out = packet_get_connection_out();
373
374 /* Read other side\'s version identification. */
375 for (;;) {
376 for (i = 0; i < sizeof(buf) - 1; i++) {
377 int len = atomicio(read, connection_in, &buf[i], 1);
378 if (len < 0)
379 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
380 if (len != 1)
381 fatal("ssh_exchange_identification: Connection closed by remote host");
382 if (buf[i] == '\r') {
383 buf[i] = '\n';
384 buf[i + 1] = 0;
385 continue; /**XXX wait for \n */
386 }
387 if (buf[i] == '\n') {
388 buf[i + 1] = 0;
389 break;
390 }
391 }
392 buf[sizeof(buf) - 1] = 0;
393 if (strncmp(buf, "SSH-", 4) == 0)
394 break;
395 debug("ssh_exchange_identification: %s", buf);
396 }
397 server_version_string = xstrdup(buf);
398
399 /*
400 * Check that the versions match. In future this might accept
401 * several versions and set appropriate flags to handle them.
402 */
403 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
404 &remote_major, &remote_minor, remote_version) != 3)
405 fatal("Bad remote protocol version identification: '%.100s'", buf);
406 debug("Remote protocol version %d.%d, remote software version %.100s",
407 remote_major, remote_minor, remote_version);
408
409 compat_datafellows(remote_version);
410 mismatch = 0;
411
412 switch(remote_major) {
413 case 1:
414 if (remote_minor == 99 &&
415 (options.protocol & SSH_PROTO_2) &&
416 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
417 enable_compat20();
418 break;
419 }
420 if (!(options.protocol & SSH_PROTO_1)) {
421 mismatch = 1;
422 break;
423 }
424 if (remote_minor < 3) {
425 fatal("Remote machine has too old SSH software version.");
426 } else if (remote_minor == 3) {
427 /* We speak 1.3, too. */
428 enable_compat13();
429 if (options.forward_agent) {
430 log("Agent forwarding disabled for protocol 1.3");
431 options.forward_agent = 0;
432 }
433 }
434 break;
435 case 2:
436 if (options.protocol & SSH_PROTO_2) {
437 enable_compat20();
438 break;
439 }
440 /* FALLTHROUGH */
441 default:
442 mismatch = 1;
443 break;
444 }
445 if (mismatch)
446 fatal("Protocol major versions differ: %d vs. %d",
447 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
448 remote_major);
449 if (compat20)
450 packet_set_ssh2_format();
451 /* Send our own protocol version identification. */
452 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
453 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
454 compat20 ? PROTOCOL_MINOR_2 : PROTOCOL_MINOR_1,
455 SSH_VERSION);
456 if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
457 fatal("write: %.100s", strerror(errno));
458 client_version_string = xstrdup(buf);
459 chop(client_version_string);
460 chop(server_version_string);
461 debug("Local version string %.100s", client_version_string);
462}
463
464int
465read_yes_or_no(const char *prompt, int defval)
466{
467 char buf[1024];
468 FILE *f;
469 int retval = -1;
470
471 if (isatty(0))
472 f = stdin;
473 else
474 f = fopen("/dev/tty", "rw");
475
476 if (f == NULL)
477 return 0;
478
479 fflush(stdout);
480
481 while (1) {
482 fprintf(stderr, "%s", prompt);
483 if (fgets(buf, sizeof(buf), f) == NULL) {
484 /* Print a newline (the prompt probably didn\'t have one). */
485 fprintf(stderr, "\n");
486 strlcpy(buf, "no", sizeof buf);
487 }
488 /* Remove newline from response. */
489 if (strchr(buf, '\n'))
490 *strchr(buf, '\n') = 0;
491
492 if (buf[0] == 0)
493 retval = defval;
494 if (strcmp(buf, "yes") == 0)
495 retval = 1;
496 if (strcmp(buf, "no") == 0)
497 retval = 0;
498
499 if (retval != -1) {
500 if (f != stdin)
501 fclose(f);
502 return retval;
503 }
504 }
505}
506
507/*
508 * check whether the supplied host key is valid, return only if ok.
509 */
510
511void
512check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
513 const char *user_hostfile, const char *system_hostfile)
514{
515 Key *file_key;
516 char *type = key_type(host_key);
517 char *ip = NULL;
518 char hostline[1000], *hostp;
519 HostStatus host_status;
520 HostStatus ip_status;
521 int local = 0, host_ip_differ = 0;
522 int salen;
523 char ntop[NI_MAXHOST];
524
525 /*
526 * Force accepting of the host key for loopback/localhost. The
527 * problem is that if the home directory is NFS-mounted to multiple
528 * machines, localhost will refer to a different machine in each of
529 * them, and the user will get bogus HOST_CHANGED warnings. This
530 * essentially disables host authentication for localhost; however,
531 * this is probably not a real problem.
532 */
533 /** hostaddr == 0! */
534 switch (hostaddr->sa_family) {
535 case AF_INET:
536 local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
537 salen = sizeof(struct sockaddr_in);
538 break;
539 case AF_INET6:
540 local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
541 salen = sizeof(struct sockaddr_in6);
542 break;
543 default:
544 local = 0;
545 salen = sizeof(struct sockaddr_storage);
546 break;
547 }
548 if (local) {
549 debug("Forcing accepting of host key for loopback/localhost.");
550 return;
551 }
552
553 /*
554 * Turn off check_host_ip for proxy connects, since
555 * we don't have the remote ip-address
556 */
557 if (options.proxy_command != NULL && options.check_host_ip)
558 options.check_host_ip = 0;
559
560 if (options.check_host_ip) {
561 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
562 NULL, 0, NI_NUMERICHOST) != 0)
563 fatal("check_host_key: getnameinfo failed");
564 ip = xstrdup(ntop);
565 }
566
567 /*
568 * Store the host key from the known host file in here so that we can
569 * compare it with the key for the IP address.
570 */
571 file_key = key_new(host_key->type);
572
573 /*
574 * Check if the host key is present in the user\'s list of known
575 * hosts or in the systemwide list.
576 */
577 host_status = check_host_in_hostfile(user_hostfile, host, host_key, file_key);
578 if (host_status == HOST_NEW)
579 host_status = check_host_in_hostfile(system_hostfile, host, host_key, file_key);
580 /*
581 * Also perform check for the ip address, skip the check if we are
582 * localhost or the hostname was an ip address to begin with
583 */
584 if (options.check_host_ip && !local && strcmp(host, ip)) {
585 Key *ip_key = key_new(host_key->type);
586 ip_status = check_host_in_hostfile(user_hostfile, ip, host_key, ip_key);
587
588 if (ip_status == HOST_NEW)
589 ip_status = check_host_in_hostfile(system_hostfile, ip, host_key, ip_key);
590 if (host_status == HOST_CHANGED &&
591 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
592 host_ip_differ = 1;
593
594 key_free(ip_key);
595 } else
596 ip_status = host_status;
597
598 key_free(file_key);
599
600 switch (host_status) {
601 case HOST_OK:
602 /* The host is known and the key matches. */
603 debug("Host '%.200s' is known and matches the %s host key.",
604 host, type);
605 if (options.check_host_ip) {
606 if (ip_status == HOST_NEW) {
607 if (!add_host_to_hostfile(user_hostfile, ip, host_key))
608 log("Failed to add the %s host key for IP address '%.30s' to the list of known hosts (%.30s).",
609 type, ip, user_hostfile);
610 else
611 log("Warning: Permanently added the %s host key for IP address '%.30s' to the list of known hosts.",
612 type, ip);
613 } else if (ip_status != HOST_OK)
614 log("Warning: the %s host key for '%.200s' differs from the key for the IP address '%.30s'",
615 type, host, ip);
616 }
617 break;
618 case HOST_NEW:
619 /* The host is new. */
620 if (options.strict_host_key_checking == 1) {
621 /* User has requested strict host key checking. We will not add the host key
622 automatically. The only alternative left is to abort. */
623 fatal("No %s host key is known for %.200s and you have requested strict checking.", type, host);
624 } else if (options.strict_host_key_checking == 2) {
625 /* The default */
626 char prompt[1024];
627 char *fp = key_fingerprint(host_key);
628 snprintf(prompt, sizeof(prompt),
629 "The authenticity of host '%.200s' can't be established.\n"
630 "%s key fingerprint is %s.\n"
631 "Are you sure you want to continue connecting (yes/no)? ",
632 host, type, fp);
633 if (!read_yes_or_no(prompt, -1))
634 fatal("Aborted by user!\n");
635 }
636 if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) {
637 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
638 hostp = hostline;
639 } else
640 hostp = host;
641
642 /* If not in strict mode, add the key automatically to the local known_hosts file. */
643 if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
644 log("Failed to add the host to the list of known hosts (%.500s).",
645 user_hostfile);
646 else
647 log("Warning: Permanently added '%.200s' (%s) to the list of known hosts.",
648 hostp, type);
649 break;
650 case HOST_CHANGED:
651 if (options.check_host_ip && host_ip_differ) {
652 char *msg;
653 if (ip_status == HOST_NEW)
654 msg = "is unknown";
655 else if (ip_status == HOST_OK)
656 msg = "is unchanged";
657 else
658 msg = "has a different value";
659 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
660 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
661 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
662 error("The %s host key for %s has changed,", type, host);
663 error("and the key for the according IP address %s", ip);
664 error("%s. This could either mean that", msg);
665 error("DNS SPOOFING is happening or the IP address for the host");
666 error("and its host key have changed at the same time");
667 }
668 /* The host key has changed. */
669 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
670 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
671 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
672 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
673 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
674 error("It is also possible that the %s host key has just been changed.", type);
675 error("Please contact your system administrator.");
676 error("Add correct host key in %.100s to get rid of this message.",
677 user_hostfile);
678
679 /*
680 * If strict host key checking is in use, the user will have
681 * to edit the key manually and we can only abort.
682 */
683 if (options.strict_host_key_checking)
684 fatal("%s host key for %.200s has changed and you have requested strict checking.", type, host);
685
686 /*
687 * If strict host key checking has not been requested, allow
688 * the connection but without password authentication or
689 * agent forwarding.
690 */
691 if (options.password_authentication) {
692 error("Password authentication is disabled to avoid trojan horses.");
693 options.password_authentication = 0;
694 }
695 if (options.forward_agent) {
696 error("Agent forwarding is disabled to avoid trojan horses.");
697 options.forward_agent = 0;
698 }
699 /*
700 * XXX Should permit the user to change to use the new id.
701 * This could be done by converting the host key to an
702 * identifying sentence, tell that the host identifies itself
703 * by that sentence, and ask the user if he/she whishes to
704 * accept the authentication.
705 */
706 break;
707 }
708 if (options.check_host_ip)
709 xfree(ip);
710}
711
712/*
713 * Starts a dialog with the server, and authenticates the current user on the
714 * server. This does not need any extra privileges. The basic connection
715 * to the server must already have been established before this is called.
716 * If login fails, this function prints an error and never returns.
717 * This function does not require super-user privileges.
718 */
719void
720ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost,
721 struct sockaddr *hostaddr, uid_t original_real_uid)
722{
723 struct passwd *pw;
724 char *host, *cp;
725 char *server_user, *local_user;
726
727 /* Get local user name. Use it as server user if no user name was given. */
728 pw = getpwuid(original_real_uid);
729 if (!pw)
730 fatal("User id %d not found from user database.", original_real_uid);
731 local_user = xstrdup(pw->pw_name);
732 server_user = options.user ? options.user : local_user;
733
734 /* Convert the user-supplied hostname into all lowercase. */
735 host = xstrdup(orighost);
736 for (cp = host; *cp; cp++)
737 if (isupper(*cp))
738 *cp = tolower(*cp);
739
740 /* Exchange protocol version identification strings with the server. */
741 ssh_exchange_identification();
742
743 /* Put the connection into non-blocking mode. */
744 packet_set_nonblocking();
745
746 /* key exchange */
747 /* authenticate user */
748 if (compat20) {
749 ssh_kex2(host, hostaddr);
750 ssh_userauth2(server_user, host);
751 } else {
752 ssh_kex(host, hostaddr);
753 ssh_userauth(local_user, server_user, host, host_key_valid, own_host_key);
754 }
755}