Annotation of src/usr.bin/ssh/sshconnect.c, Revision 1.2
1.1 deraadt 1: /*
2:
3: sshconnect.c
4:
5: Author: Tatu Ylonen <ylo@cs.hut.fi>
6:
7: Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: All rights reserved
9:
10: Created: Sat Mar 18 22:15:47 1995 ylo
11:
12: Code to connect to a remote host, and to perform the client side of the
13: login (authentication) dialog.
14:
15: */
16:
17: #include "includes.h"
1.2 ! deraadt 18: RCSID("$Id: sshconnect.c,v 1.1 1999/09/26 20:53:38 deraadt Exp $");
1.1 deraadt 19:
20: #include <gmp.h>
21: #include "xmalloc.h"
22: #include "randoms.h"
23: #include "rsa.h"
24: #include "ssh.h"
25: #include "packet.h"
26: #include "authfd.h"
27: #include "cipher.h"
28: #include "ssh_md5.h"
29: #include "mpaux.h"
30: #include "uidswap.h"
31:
32: #ifdef KRB4
33: #include <krb.h>
34: #ifdef AFS
35: #if defined(HAVE_SYS_IOCTL_H) && SunOS != 4
36: #include <sys/ioctl.h>
37: #endif
38: #ifdef HAVE_SYS_FILIO_H
39: #include <sys/filio.h>
40: #endif
41: #include <kafs.h>
42: #endif /* AFS */
43: #endif /* KRB4 */
44:
45: /* Session id for the current session. */
46: unsigned char session_id[16];
47:
48: /* Connect to the given ssh server using a proxy command. */
49:
50: int ssh_proxy_connect(const char *host, int port, uid_t original_real_uid,
51: const char *proxy_command, RandomState *random_state)
52: {
53: Buffer command;
54: const char *cp;
55: char *command_string;
56: int pin[2], pout[2];
57: int pid;
58: char portstring[100];
59:
60: /* Convert the port number into a string. */
61: sprintf(portstring, "%d", port);
62:
63: /* Build the final command string in the buffer by making the appropriate
64: substitutions to the given proxy command. */
65: buffer_init(&command);
66: for (cp = proxy_command; *cp; cp++)
67: {
68: if (cp[0] == '%' && cp[1] == '%')
69: {
70: buffer_append(&command, "%", 1);
71: cp++;
72: continue;
73: }
74: if (cp[0] == '%' && cp[1] == 'h')
75: {
76: buffer_append(&command, host, strlen(host));
77: cp++;
78: continue;
79: }
80: if (cp[0] == '%' && cp[1] == 'p')
81: {
82: buffer_append(&command, portstring, strlen(portstring));
83: cp++;
84: continue;
85: }
86: buffer_append(&command, cp, 1);
87: }
88: buffer_append(&command, "\0", 1);
89:
90: /* Get the final command string. */
91: command_string = buffer_ptr(&command);
92:
93: /* Create pipes for communicating with the proxy. */
94: if (pipe(pin) < 0 || pipe(pout) < 0)
95: fatal("Could not create pipes to communicate with the proxy: %.100s",
96: strerror(errno));
97:
98: debug("Executing proxy command: %.500s", command_string);
99:
100: /* Fork and execute the proxy command. */
101: if ((pid = fork()) == 0)
102: {
103: char *argv[10];
104:
105: /* Child. Permanently give up superuser privileges. */
106: permanently_set_uid(original_real_uid);
107:
108: /* Redirect stdin and stdout. */
109: close(pin[1]);
110: if (pin[0] != 0)
111: {
112: if (dup2(pin[0], 0) < 0)
113: perror("dup2 stdin");
114: close(pin[0]);
115: }
116: close(pout[0]);
117: if (dup2(pout[1], 1) < 0)
118: perror("dup2 stdout");
119: close(pout[1]); /* Cannot be 1 because pin allocated two descriptors. */
120:
121: /* Stderr is left as it is so that error messages get printed on
122: the user's terminal. */
123: argv[0] = "/bin/sh";
124: argv[1] = "-c";
125: argv[2] = command_string;
126: argv[3] = NULL;
127:
128: /* Execute the proxy command. Note that we gave up any extra
129: privileges above. */
130: execv("/bin/sh", argv);
131: perror("/bin/sh");
132: exit(1);
133: }
134: /* Parent. */
135: if (pid < 0)
136: fatal("fork failed: %.100s", strerror(errno));
137:
138: /* Close child side of the descriptors. */
139: close(pin[0]);
140: close(pout[1]);
141:
142: /* Free the command name. */
143: buffer_free(&command);
144:
145: /* Set the connection file descriptors. */
146: packet_set_connection(pout[0], pin[1], random_state);
147:
148: return 1;
149: }
150:
151: /* Creates a (possibly privileged) socket for use as the ssh connection. */
152:
153: int ssh_create_socket(uid_t original_real_uid, int privileged)
154: {
155: int sock;
156:
157: /* If we are running as root and want to connect to a privileged port,
158: bind our own socket to a privileged port. */
159: if (privileged)
160: {
161: struct sockaddr_in sin;
1.2 ! deraadt 162: int p = IPPORT_RESERVED - 1;
! 163:
! 164: sock = rresvport(&p);
! 165: if (sock < 0)
! 166: fatal("rresvport: %.100s", strerror(errno));
1.1 deraadt 167: debug("Allocated local port %d.", p);
168: }
169: else
170: {
171: /* Just create an ordinary socket on arbitrary port. We use the
172: user's uid to create the socket. */
173: temporarily_use_uid(original_real_uid);
174: sock = socket(AF_INET, SOCK_STREAM, 0);
175: if (sock < 0)
176: fatal("socket: %.100s", strerror(errno));
177: restore_uid();
178: }
179: return sock;
180: }
181:
182: /* Opens a TCP/IP connection to the remote server on the given host. If
183: port is 0, the default port will be used. If anonymous is zero,
184: a privileged port will be allocated to make the connection.
185: This requires super-user privileges if anonymous is false.
186: Connection_attempts specifies the maximum number of tries (one per
187: second). If proxy_command is non-NULL, it specifies the command (with %h
188: and %p substituted for host and port, respectively) to use to contact
189: the daemon. */
190:
191: int ssh_connect(const char *host, int port, int connection_attempts,
192: int anonymous, uid_t original_real_uid,
193: const char *proxy_command, RandomState *random_state)
194: {
195: int sock = -1, attempt, i;
196: int on = 1;
197: struct servent *sp;
198: struct hostent *hp;
199: struct sockaddr_in hostaddr;
200: #ifdef SO_LINGER
201: struct linger linger;
202: #endif /* SO_LINGER */
203:
204: debug("ssh_connect: getuid %d geteuid %d anon %d",
205: (int)getuid(), (int)geteuid(), anonymous);
206:
207: /* Get default port if port has not been set. */
208: if (port == 0)
209: {
210: sp = getservbyname(SSH_SERVICE_NAME, "tcp");
211: if (sp)
212: port = ntohs(sp->s_port);
213: else
214: port = SSH_DEFAULT_PORT;
215: }
216:
217: /* If a proxy command is given, connect using it. */
218: if (proxy_command != NULL)
219: return ssh_proxy_connect(host, port, original_real_uid, proxy_command,
220: random_state);
221:
222: /* No proxy command. */
223:
224: /* No host lookup made yet. */
225: hp = NULL;
226:
227: /* Try to connect several times. On some machines, the first time will
228: sometimes fail. In general socket code appears to behave quite
229: magically on many machines. */
230: for (attempt = 0; attempt < connection_attempts; attempt++)
231: {
232: if (attempt > 0)
233: debug("Trying again...");
234:
235: /* Try to parse the host name as a numeric inet address. */
236: memset(&hostaddr, 0, sizeof(hostaddr));
237: hostaddr.sin_family = AF_INET;
238: hostaddr.sin_port = htons(port);
239: #ifdef BROKEN_INET_ADDR
240: hostaddr.sin_addr.s_addr = inet_network(host);
241: #else /* BROKEN_INET_ADDR */
242: hostaddr.sin_addr.s_addr = inet_addr(host);
243: #endif /* BROKEN_INET_ADDR */
244: if ((hostaddr.sin_addr.s_addr & 0xffffffff) != 0xffffffff)
245: {
246: /* Valid numeric IP address */
247: debug("Connecting to %.100s port %d.",
248: inet_ntoa(hostaddr.sin_addr), port);
249:
250: /* Create a socket. */
251: sock = ssh_create_socket(original_real_uid,
252: !anonymous && geteuid() == 0 &&
253: port < 1024);
254:
255: /* Connect to the host. We use the user's uid in the hope that
256: it will help with the problems of tcp_wrappers showing the
257: remote uid as root. */
258: temporarily_use_uid(original_real_uid);
259: if (connect(sock, (struct sockaddr *)&hostaddr, sizeof(hostaddr))
260: >= 0)
261: {
262: /* Successful connect. */
263: restore_uid();
264: break;
265: }
266: debug("connect: %.100s", strerror(errno));
267: restore_uid();
268:
269: /* Destroy the failed socket. */
270: shutdown(sock, 2);
271: close(sock);
272: }
273: else
274: {
275: /* Not a valid numeric inet address. */
276: /* Map host name to an address. */
277: if (!hp)
278: hp = gethostbyname(host);
279: if (!hp)
280: fatal("Bad host name: %.100s", host);
281: if (!hp->h_addr_list[0])
282: fatal("Host does not have an IP address: %.100s", host);
283:
284: /* Loop through addresses for this host, and try each one in
285: sequence until the connection succeeds. */
286: for (i = 0; hp->h_addr_list[i]; i++)
287: {
288: /* Set the address to connect to. */
289: hostaddr.sin_family = hp->h_addrtype;
290: memcpy(&hostaddr.sin_addr, hp->h_addr_list[i],
291: sizeof(hostaddr.sin_addr));
292:
293: debug("Connecting to %.200s [%.100s] port %d.",
294: host, inet_ntoa(hostaddr.sin_addr), port);
295:
296: /* Create a socket for connecting. */
297: sock = ssh_create_socket(original_real_uid,
298: !anonymous && geteuid() == 0 &&
299: port < 1024);
300:
301: /* Connect to the host. We use the user's uid in the hope that
302: it will help with tcp_wrappers showing the remote uid as
303: root. */
304: temporarily_use_uid(original_real_uid);
305: if (connect(sock, (struct sockaddr *)&hostaddr,
306: sizeof(hostaddr)) >= 0)
307: {
308: /* Successful connection. */
309: restore_uid();
310: break;
311: }
312: debug("connect: %.100s", strerror(errno));
313: restore_uid();
314:
315: /* Close the failed socket; there appear to be some problems
316: when reusing a socket for which connect() has already
317: returned an error. */
318: shutdown(sock, 2);
319: close(sock);
320: }
321: if (hp->h_addr_list[i])
322: break; /* Successful connection. */
323: }
324:
325: /* Sleep a moment before retrying. */
326: sleep(1);
327: }
328: /* Return failure if we didn't get a successful connection. */
329: if (attempt >= connection_attempts)
330: return 0;
331:
332: debug("Connection established.");
333:
334: /* Set socket options. We would like the socket to disappear as soon as
335: it has been closed for whatever reason. */
336: /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
337: #ifdef TCP_NODELAY
338: setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void *)&on, sizeof(on));
339: #endif /* TCP_NODELAY */
340: #ifdef SO_LINGER
341: linger.l_onoff = 1;
342: linger.l_linger = 5;
343: setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
344: #endif /* SO_LINGER */
345:
346: /* Set the connection. */
347: packet_set_connection(sock, sock, random_state);
348:
349: return 1;
350: }
351:
352: /* Checks if the user has an authentication agent, and if so, tries to
353: authenticate using the agent. */
354:
355: int try_agent_authentication()
356: {
357: int status, type, bits;
358: MP_INT e, n, challenge;
359: char *comment;
360: AuthenticationConnection *auth;
361: unsigned char response[16];
362: unsigned int i;
363:
364: /* Get connection to the agent. */
365: auth = ssh_get_authentication_connection();
366: if (!auth)
367: return 0;
368:
369: mpz_init(&e);
370: mpz_init(&n);
371: mpz_init(&challenge);
372:
373: /* Loop through identities served by the agent. */
374: for (status = ssh_get_first_identity(auth, &bits, &e, &n, &comment);
375: status;
376: status = ssh_get_next_identity(auth, &bits, &e, &n, &comment))
377: {
378: int plen, clen;
379:
380: /* Try this identity. */
381: debug("Trying RSA authentication via agent with '%.100s'", comment);
382: xfree(comment);
383:
384: /* Tell the server that we are willing to authenticate using this key. */
385: packet_start(SSH_CMSG_AUTH_RSA);
386: packet_put_mp_int(&n);
387: packet_send();
388: packet_write_wait();
389:
390: /* Wait for server's response. */
391: type = packet_read(&plen);
392:
393: /* The server sends failure if it doesn\'t like our key or does not
394: support RSA authentication. */
395: if (type == SSH_SMSG_FAILURE)
396: {
397: debug("Server refused our key.");
398: continue;
399: }
400:
401: /* Otherwise it should have sent a challenge. */
402: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
403: packet_disconnect("Protocol error during RSA authentication: %d",
404: type);
405:
406: packet_get_mp_int(&challenge, &clen);
407:
408: packet_integrity_check(plen, clen, type);
409:
410: debug("Received RSA challenge from server.");
411:
412: /* Ask the agent to decrypt the challenge. */
413: if (!ssh_decrypt_challenge(auth, bits, &e, &n, &challenge,
414: session_id, 1, response))
415: {
416: /* The agent failed to authenticate this identifier although it
417: advertised it supports this. Just return a wrong value. */
418: log("Authentication agent failed to decrypt challenge.");
419: memset(response, 0, sizeof(response));
420: }
421:
422: debug("Sending response to RSA challenge.");
423:
424: /* Send the decrypted challenge back to the server. */
425: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
426: for (i = 0; i < 16; i++)
427: packet_put_char(response[i]);
428: packet_send();
429: packet_write_wait();
430:
431: /* Wait for response from the server. */
432: type = packet_read(&plen);
433:
434: /* The server returns success if it accepted the authentication. */
435: if (type == SSH_SMSG_SUCCESS)
436: {
437: debug("RSA authentication accepted by server.");
438: mpz_clear(&e);
439: mpz_clear(&n);
440: mpz_clear(&challenge);
441: return 1;
442: }
443:
444: /* Otherwise it should return failure. */
445: if (type != SSH_SMSG_FAILURE)
446: packet_disconnect("Protocol error waiting RSA auth response: %d",
447: type);
448: }
449:
450: mpz_clear(&e);
451: mpz_clear(&n);
452: mpz_clear(&challenge);
453:
454: debug("RSA authentication using agent refused.");
455: return 0;
456: }
457:
458: /* Computes the proper response to a RSA challenge, and sends the response to
459: the server. */
460:
461: void respond_to_rsa_challenge(MP_INT *challenge, RSAPrivateKey *prv)
462: {
463: unsigned char buf[32], response[16];
464: struct MD5Context md;
465: int i;
466:
467: /* Decrypt the challenge using the private key. */
468: rsa_private_decrypt(challenge, challenge, prv);
469:
470: /* Compute the response. */
471: /* The response is MD5 of decrypted challenge plus session id. */
472: mp_linearize_msb_first(buf, 32, challenge);
473: MD5Init(&md);
474: MD5Update(&md, buf, 32);
475: MD5Update(&md, session_id, 16);
476: MD5Final(response, &md);
477:
478: debug("Sending response to host key RSA challenge.");
479:
480: /* Send the response back to the server. */
481: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
482: for (i = 0; i < 16; i++)
483: packet_put_char(response[i]);
484: packet_send();
485: packet_write_wait();
486:
487: memset(buf, 0, sizeof(buf));
488: memset(response, 0, sizeof(response));
489: memset(&md, 0, sizeof(md));
490: }
491:
492: /* Checks if the user has authentication file, and if so, tries to authenticate
493: the user using it. */
494:
495: int try_rsa_authentication(struct passwd *pw, const char *authfile,
496: int may_ask_passphrase)
497: {
498: MP_INT challenge;
499: RSAPrivateKey private_key;
500: RSAPublicKey public_key;
501: char *passphrase, *comment;
502: int type, i;
503: int plen, clen;
504:
505: /* Try to load identification for the authentication key. */
506: if (!load_public_key(authfile, &public_key, &comment))
507: return 0; /* Could not load it. Fail. */
508:
509: debug("Trying RSA authentication with key '%.100s'", comment);
510:
511: /* Tell the server that we are willing to authenticate using this key. */
512: packet_start(SSH_CMSG_AUTH_RSA);
513: packet_put_mp_int(&public_key.n);
514: packet_send();
515: packet_write_wait();
516:
517: /* We no longer need the public key. */
518: rsa_clear_public_key(&public_key);
519:
520: /* Wait for server's response. */
521: type = packet_read(&plen);
522:
523: /* The server responds with failure if it doesn\'t like our key or doesn\'t
524: support RSA authentication. */
525: if (type == SSH_SMSG_FAILURE)
526: {
527: debug("Server refused our key.");
528: xfree(comment);
529: return 0; /* Server refuses to authenticate with this key. */
530: }
531:
532: /* Otherwise, the server should respond with a challenge. */
533: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
534: packet_disconnect("Protocol error during RSA authentication: %d", type);
535:
536: /* Get the challenge from the packet. */
537: mpz_init(&challenge);
538: packet_get_mp_int(&challenge, &clen);
539:
540: packet_integrity_check(plen, clen, type);
541:
542: debug("Received RSA challenge from server.");
543:
544: /* Load the private key. Try first with empty passphrase; if it fails,
545: ask for a passphrase. */
546: if (!load_private_key(authfile, "", &private_key, NULL))
547: {
548: char buf[300];
549: /* Request passphrase from the user. We read from /dev/tty to make
550: this work even if stdin has been redirected. If running in
551: batch mode, we just use the empty passphrase, which will fail and
552: return. */
553: sprintf(buf, "Enter passphrase for RSA key '%.100s': ", comment);
554: if (may_ask_passphrase)
555: passphrase = read_passphrase(buf, 0);
556: else
557: {
558: debug("Will not query passphrase for %.100s in batch mode.",
559: comment);
560: passphrase = xstrdup("");
561: }
562:
563: /* Load the authentication file using the pasphrase. */
564: if (!load_private_key(authfile, passphrase, &private_key, NULL))
565: {
566: memset(passphrase, 0, strlen(passphrase));
567: xfree(passphrase);
568: error("Bad passphrase.");
569:
570: /* Send a dummy response packet to avoid protocol error. */
571: packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
572: for (i = 0; i < 16; i++)
573: packet_put_char(0);
574: packet_send();
575: packet_write_wait();
576:
577: /* Expect the server to reject it... */
578: packet_read_expect(&plen, SSH_SMSG_FAILURE);
579: xfree(comment);
580: return 0;
581: }
582:
583: /* Destroy the passphrase. */
584: memset(passphrase, 0, strlen(passphrase));
585: xfree(passphrase);
586: }
587:
588: /* We no longer need the comment. */
589: xfree(comment);
590:
591: /* Compute and send a response to the challenge. */
592: respond_to_rsa_challenge(&challenge, &private_key);
593:
594: /* Destroy the private key. */
595: rsa_clear_private_key(&private_key);
596:
597: /* We no longer need the challenge. */
598: mpz_clear(&challenge);
599:
600: /* Wait for response from the server. */
601: type = packet_read(&plen);
602: if (type == SSH_SMSG_SUCCESS)
603: {
604: debug("RSA authentication accepted by server.");
605: return 1;
606: }
607: if (type != SSH_SMSG_FAILURE)
608: packet_disconnect("Protocol error waiting RSA auth response: %d", type);
609: debug("RSA authentication refused.");
610: return 0;
611: }
612:
613: /* Tries to authenticate the user using combined rhosts or /etc/hosts.equiv
614: authentication and RSA host authentication. */
615:
616: int try_rhosts_rsa_authentication(const char *local_user,
617: RSAPrivateKey *host_key)
618: {
619: int type;
620: MP_INT challenge;
621: int plen, clen;
622:
623: debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication.");
624:
625: /* Tell the server that we are willing to authenticate using this key. */
626: packet_start(SSH_CMSG_AUTH_RHOSTS_RSA);
627: packet_put_string(local_user, strlen(local_user));
628: packet_put_int(host_key->bits);
629: packet_put_mp_int(&host_key->e);
630: packet_put_mp_int(&host_key->n);
631: packet_send();
632: packet_write_wait();
633:
634: /* Wait for server's response. */
635: type = packet_read(&plen);
636:
637: /* The server responds with failure if it doesn't admit our .rhosts
638: authentication or doesn't know our host key. */
639: if (type == SSH_SMSG_FAILURE)
640: {
641: debug("Server refused our rhosts authentication or host key.");
642: return 0; /* Server refuses to authenticate us with this method. */
643: }
644:
645: /* Otherwise, the server should respond with a challenge. */
646: if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
647: packet_disconnect("Protocol error during RSA authentication: %d", type);
648:
649: /* Get the challenge from the packet. */
650: mpz_init(&challenge);
651: packet_get_mp_int(&challenge, &clen);
652:
653: packet_integrity_check(plen, clen, type);
654:
655: debug("Received RSA challenge for host key from server.");
656:
657: /* Compute a response to the challenge. */
658: respond_to_rsa_challenge(&challenge, host_key);
659:
660: /* We no longer need the challenge. */
661: mpz_clear(&challenge);
662:
663: /* Wait for response from the server. */
664: type = packet_read(&plen);
665: if (type == SSH_SMSG_SUCCESS)
666: {
667: debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server.");
668: return 1;
669: }
670: if (type != SSH_SMSG_FAILURE)
671: packet_disconnect("Protocol error waiting RSA auth response: %d", type);
672: debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused.");
673: return 0;
674: }
675:
676: #ifdef KRB4
677: int try_kerberos_authentication()
678: {
679: KTEXT_ST auth; /* Kerberos data */
680: char *reply;
681: char inst[INST_SZ];
682: char *realm;
683: CREDENTIALS cred;
684: int r, type;
685: Key_schedule schedule;
686: u_long checksum, cksum;
687: MSG_DAT msg_data;
688: struct sockaddr_in local, foreign;
689: struct stat st;
690: int plen;
691:
692: /* Don't do anything if we don't have any tickets. */
693: if (stat(tkt_string(), &st) < 0) return 0;
694:
695: debug("Trying Kerberos authentication.");
696: strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ);
697:
698: realm = (char *)krb_realmofhost(get_canonical_hostname());
699: if (!realm) {
700: debug("Kerberos V4: no realm for %.100s", get_canonical_hostname());
701: return 0;
702: }
703: /* This can really be anything. */
704: checksum = (u_long) getpid();
705:
706: r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum);
707: if (r != KSUCCESS) {
708: debug("Kerberos V4 krb_mk_req failed: %.100s", krb_err_txt[r]);
709: return 0;
710: }
711: /* Get session key to decrypt the server's reply with. */
712: r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred);
713: if (r != KSUCCESS) {
714: debug("get_cred failed: %.100s", krb_err_txt[r]);
715: return 0;
716: }
717: des_key_sched((des_cblock *)cred.session, schedule);
718:
719: /* Send authentication info to server. */
720: packet_start(SSH_CMSG_AUTH_KERBEROS);
721: packet_put_string((char *)auth.dat, auth.length);
722: packet_send();
723: packet_write_wait();
724:
725: /* zero the buffer */
726: (void) memset(auth.dat, 0, MAX_KTXT_LEN);
727:
728: r = sizeof(local);
729: memset(&local, 0, sizeof(local));
730: if (getsockname(packet_get_connection_in(),
731: (struct sockaddr *) &local, &r) < 0)
732: debug("getsockname failed: %.100s", strerror(errno));
733:
734: r = sizeof(foreign);
735: memset(&foreign, 0, sizeof(foreign));
736: if (getpeername(packet_get_connection_in(),
737: (struct sockaddr *)&foreign, &r) < 0)
738: debug("getpeername failed: %.100s", strerror(errno));
739:
740: /* Get server reply. */
741: type = packet_read(&plen);
742: switch(type) {
743:
744: case SSH_SMSG_FAILURE: /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */
745: debug("Kerberos V4 authentication failed.");
746: return 0;
747: break;
748:
749: case SSH_SMSG_AUTH_KERBEROS_RESPONSE: /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */
750: debug("Kerberos V4 authentication accepted.");
751:
752: /* Get server's response. */
753: reply = packet_get_string((unsigned int *)&auth.length);
754: memcpy(auth.dat, reply, auth.length);
755: xfree(reply);
756:
757: packet_integrity_check(plen, 4 + auth.length, type);
758:
759: /* If his response isn't properly encrypted with the session key,
760: and the decrypted checksum fails to match, he's bogus. Bail out. */
761: r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session,
762: &foreign, &local, &msg_data);
763: if (r != KSUCCESS) {
764: debug("Kerberos V4 krb_rd_priv failed: %.100s", krb_err_txt[r]);
765: packet_disconnect("Kerberos V4 challenge failed!");
766: }
767: /* fetch the (incremented) checksum that we supplied in the request */
768: (void)memcpy((char *)&cksum, (char *)msg_data.app_data, sizeof(cksum));
769: cksum = ntohl(cksum);
770:
771: /* If it matches, we're golden. */
772: if (cksum == checksum + 1) {
773: debug("Kerberos V4 challenge successful.");
774: return 1;
775: }
776: else
777: packet_disconnect("Kerberos V4 challenge failed!");
778: break;
779:
780: default:
781: packet_disconnect("Protocol error on Kerberos V4 response: %d", type);
782: }
783: return 0;
784: }
785: #endif /* KRB4 */
786:
787: #ifdef AFS
788:
789: #ifdef KERBEROS_TGT_PASSING
790: int send_kerberos_tgt()
791: {
792: CREDENTIALS *creds;
793: char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];
794: int r, plen, type;
795: unsigned char buffer[8192];
796: struct stat st;
797:
798: /* Don't do anything if we don't have any tickets. */
799: if (stat(tkt_string(), &st) < 0) return 0;
800:
801: creds = xmalloc(sizeof(CREDENTIALS));
802:
803: if ((r=krb_get_tf_fullname(TKT_FILE,pname,pinst,prealm)) != KSUCCESS) {
804: debug("Kerberos V4 tf_fullname failed: %.100s",krb_err_txt[r]);
805: return 0;
806: }
807: if ((r=krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) {
808: debug("Kerberos V4 get_cred failed: %.100s", krb_err_txt[r]);
809: return 0;
810: }
811: if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) {
812: debug("Kerberos V4 ticket expired: %.100s", TKT_FILE);
813: return 0;
814: }
815:
816: creds_to_radix(creds, buffer);
817: xfree(creds);
818:
819: packet_start(SSH_CMSG_HAVE_KERBEROS_TGT);
820: packet_put_string((char *)buffer, strlen(buffer));
821: packet_send();
822: packet_write_wait();
823:
824: type = packet_read(&plen);
825:
826: if (type == SSH_SMSG_FAILURE)
827: debug("Kerberos TGT for realm %.100s rejected.", prealm);
828: else if (type != SSH_SMSG_SUCCESS)
829: packet_disconnect("Protocol error on Kerberos TGT response: %d", type);
830:
831: return 1;
832: }
833: #endif /* KERBEROS_TGT_PASSING */
834:
835: /* Forwards our AFS tokens to the server. */
836: void send_afs_tokens(void)
837: {
838: CREDENTIALS creds;
839: struct ViceIoctl parms;
840: struct ClearToken ct;
841: int i, type;
842: int len, plen;
843: char buf[2048], *p, *server_cell;
844: unsigned char buffer[8192];
845:
846: /* Move over ktc_GetToken, here's something leaner. */
847: for (i = 0; i < 100; i++) { /* just in case */
848: parms.in = (char *)&i;
849: parms.in_size = sizeof(i);
850: parms.out = buf;
851: parms.out_size = sizeof(buf);
852: if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) break;
853: p = buf;
854:
855: /* Get secret token. */
856: memcpy(&creds.ticket_st.length, p, sizeof(unsigned int));
857: if (creds.ticket_st.length > MAX_KTXT_LEN) break;
858: p += sizeof(unsigned int);
859: memcpy(creds.ticket_st.dat, p, creds.ticket_st.length);
860: p += creds.ticket_st.length;
861:
862: /* Get clear token. */
863: memcpy(&len, p, sizeof(len));
864: if (len != sizeof(struct ClearToken)) break;
865: p += sizeof(len);
866: memcpy(&ct, p, len);
867: p += len;
868: p += sizeof(len); /* primary flag */
869: server_cell = p;
870:
871: /* Flesh out our credentials. */
872: strcpy(creds.service, "afs");
873: creds.instance[0] = '\0';
874: strncpy(creds.realm, server_cell, REALM_SZ);
875: memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ);
876: creds.issue_date = ct.BeginTimestamp;
877: creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp);
878: creds.kvno = ct.AuthHandle;
879: sprintf(creds.pname, "AFS ID %d", ct.ViceId);
880: creds.pinst[0] = '\0';
881:
882: /* Encode token, ship it off. */
883: if (!creds_to_radix(&creds, buffer)) break;
884: packet_start(SSH_CMSG_HAVE_AFS_TOKEN);
885: packet_put_string((char *)buffer, strlen(buffer));
886: packet_send();
887: packet_write_wait();
888:
889: /* Roger, Roger. Clearance, Clarence. What's your vector, Victor? */
890: type = packet_read(&plen);
891:
892: if (type == SSH_SMSG_FAILURE)
893: debug("AFS token for cell %.100s rejected.", server_cell);
894: else if (type != SSH_SMSG_SUCCESS)
895: packet_disconnect("Protocol error on AFS token response: %d", type);
896: }
897: }
898: #endif /* AFS */
899:
900: /* Waits for the server identification string, and sends our own identification
901: string. */
902:
903: void ssh_exchange_identification()
904: {
905: char buf[256], remote_version[256]; /* must be same size! */
906: int remote_major, remote_minor, i;
907: int connection_in = packet_get_connection_in();
908: int connection_out = packet_get_connection_out();
909:
910: /* Read other side\'s version identification. */
911: for (i = 0; i < sizeof(buf) - 1; i++)
912: {
913: if (read(connection_in, &buf[i], 1) != 1)
914: fatal("read: %.100s", strerror(errno));
915: if (buf[i] == '\r')
916: {
917: buf[i] = '\n';
918: buf[i + 1] = 0;
919: break;
920: }
921: if (buf[i] == '\n')
922: {
923: buf[i + 1] = 0;
924: break;
925: }
926: }
927: buf[sizeof(buf) - 1] = 0;
928:
929: /* Check that the versions match. In future this might accept several
930: versions and set appropriate flags to handle them. */
931: if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
932: remote_version) != 3)
933: fatal("Bad remote protocol version identification: '%.100s'", buf);
934: debug("Remote protocol version %d.%d, remote software version %.100s",
935: remote_major, remote_minor, remote_version);
936: #if 0
937: /* Removed for now, to permit compatibility with latter versions. The server
938: will reject our version and disconnect if it doesn't support it. */
939: if (remote_major != PROTOCOL_MAJOR)
940: fatal("Protocol major versions differ: %d vs. %d",
941: PROTOCOL_MAJOR, remote_major);
942: #endif
943:
944: /* Check if the remote protocol version is too old. */
945: if (remote_major == 1 && remote_minor == 0)
946: fatal("Remote machine has too old SSH software version.");
947:
948: /* Send our own protocol version identification. */
949: sprintf(buf, "SSH-%d.%d-%.100s\n",
950: PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
951: if (write(connection_out, buf, strlen(buf)) != strlen(buf))
952: fatal("write: %.100s", strerror(errno));
953: }
954:
955: int ssh_cipher_default = SSH_CIPHER_3DES;
956:
957: int read_yes_or_no(const char *prompt, int defval)
958: {
959: char buf[1024];
960: FILE *f;
961: int retval = -1;
962:
963: if (isatty(0))
964: f = stdin;
965: else
966: f = fopen("/dev/tty", "rw");
967:
968: if (f == NULL)
969: return 0;
970:
971: fflush(stdout);
972:
973: while (1)
974: {
975: fprintf(stderr, "%s", prompt);
976: if (fgets(buf, sizeof(buf), f) == NULL)
977: {
978: /* Print a newline (the prompt probably didn\'t have one). */
979: fprintf(stderr, "\n");
980: strcpy(buf, "no");
981: }
982: /* Remove newline from response. */
983: if (strchr(buf, '\n'))
984: *strchr(buf, '\n') = 0;
985:
986: if (buf[0] == 0)
987: retval = defval;
988: if (strcmp(buf, "yes") == 0)
989: retval = 1;
990: if (strcmp(buf, "no") == 0)
991: retval = 0;
992:
993: if (retval != -1)
994: {
995: if (f != stdin)
996: fclose(f);
997: return retval;
998: }
999: }
1000: }
1001:
1002: /* Starts a dialog with the server, and authenticates the current user on the
1003: server. This does not need any extra privileges. The basic connection
1004: to the server must already have been established before this is called.
1005: User is the remote user; if it is NULL, the current local user name will
1006: be used. Anonymous indicates that no rhosts authentication will be used.
1007: If login fails, this function prints an error and never returns.
1008: This function does not require super-user privileges. */
1009:
1010: void ssh_login(RandomState *state, int host_key_valid,
1011: RSAPrivateKey *own_host_key,
1012: const char *orighost,
1013: Options *options, uid_t original_real_uid)
1014: {
1015: int i, type;
1016: char buf[1024];
1017: char *password;
1018: struct passwd *pw;
1019: MP_INT key;
1020: RSAPublicKey host_key;
1021: RSAPublicKey public_key;
1022: unsigned char session_key[SSH_SESSION_KEY_LENGTH];
1023: const char *server_user, *local_user;
1024: char *cp, *host;
1025: struct stat st;
1026: unsigned char check_bytes[8];
1027: unsigned int supported_ciphers, supported_authentications, protocol_flags;
1028: HostStatus host_status;
1029: int payload_len, clen, sum_len = 0;
1030:
1031: /* Convert the user-supplied hostname into all lowercase. */
1032: host = xstrdup(orighost);
1033: for (cp = host; *cp; cp++)
1034: if (isupper(*cp))
1035: *cp = tolower(*cp);
1036:
1037: /* Exchange protocol version identification strings with the server. */
1038: ssh_exchange_identification();
1039:
1040: /* Put the connection into non-blocking mode. */
1041: packet_set_nonblocking();
1042:
1043: /* Get local user name. Use it as server user if no user name
1044: was given. */
1045: pw = getpwuid(original_real_uid);
1046: if (!pw)
1047: fatal("User id %d not found from user database.", original_real_uid);
1048: local_user = xstrdup(pw->pw_name);
1049: server_user = options->user ? options->user : local_user;
1050:
1051: debug("Waiting for server public key.");
1052:
1053: /* Wait for a public key packet from the server. */
1054: packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY);
1055:
1056: /* Get check bytes from the packet. */
1057: for (i = 0; i < 8; i++)
1058: check_bytes[i] = packet_get_char();
1059:
1060: /* Get the public key. */
1061: public_key.bits = packet_get_int();
1062: mpz_init(&public_key.e);
1063: packet_get_mp_int(&public_key.e, &clen);
1064: sum_len += clen;
1065: mpz_init(&public_key.n);
1066: packet_get_mp_int(&public_key.n, &clen);
1067: sum_len += clen;
1068:
1069: /* Get the host key. */
1070: host_key.bits = packet_get_int();
1071: mpz_init(&host_key.e);
1072: packet_get_mp_int(&host_key.e, &clen);
1073: sum_len += clen;
1074: mpz_init(&host_key.n);
1075: packet_get_mp_int(&host_key.n, &clen);
1076: sum_len += clen;
1077:
1078: /* Get protocol flags. */
1079: protocol_flags = packet_get_int();
1080: packet_set_protocol_flags(protocol_flags);
1081:
1082: /* Get supported cipher types. */
1083: supported_ciphers = packet_get_int();
1084:
1085: /* Get supported authentication types. */
1086: supported_authentications = packet_get_int();
1087:
1088: debug("Received server public key (%d bits) and host key (%d bits).",
1089: public_key.bits, host_key.bits);
1090:
1091: packet_integrity_check(payload_len,
1092: 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4,
1093: SSH_SMSG_PUBLIC_KEY);
1094:
1095: /* Compute the session id. */
1096: compute_session_id(session_id, check_bytes, host_key.bits, &host_key.n,
1097: public_key.bits, &public_key.n);
1098:
1099: /* Check if the host key is present in the user\'s list of known hosts
1100: or in the systemwide list. */
1101: host_status = check_host_in_hostfile(options->user_hostfile,
1102: host, host_key.bits,
1103: &host_key.e, &host_key.n);
1104: if (host_status == HOST_NEW)
1105: host_status = check_host_in_hostfile(options->system_hostfile, host,
1106: host_key.bits, &host_key.e,
1107: &host_key.n);
1108:
1109: /* Force accepting of the host key for localhost and 127.0.0.1.
1110: The problem is that if the home directory is NFS-mounted to multiple
1111: machines, localhost will refer to a different machine in each of them,
1112: and the user will get bogus HOST_CHANGED warnings. This essentially
1113: disables host authentication for localhost; however, this is probably
1114: not a real problem. */
1115: if (strcmp(host, "localhost") == 0 ||
1116: strcmp(host, "127.0.0.1") == 0)
1117: {
1118: debug("Forcing accepting of host key for localhost.");
1119: host_status = HOST_OK;
1120: }
1121:
1122: switch (host_status)
1123: {
1124: case HOST_OK:
1125: /* The host is known and the key matches. */
1126: debug("Host '%.200s' is known and matches the host key.", host);
1127: break;
1128: case HOST_NEW:
1129: /* The host is new. */
1130: if (options->strict_host_key_checking == 1)
1131: { /* User has requested strict host key checking. We will not
1132: add the host key automatically. The only alternative left
1133: is to abort. */
1134: fatal("No host key is known for %.200s and you have requested strict checking.", host);
1135: }
1136: else if (options->strict_host_key_checking == 2) /* The default */
1137: {
1138: char prompt[1024];
1139: sprintf(prompt,
1140: "The authenticity of host '%.200s' can't be established.\n"
1141: "Are you sure you want to continue connecting (yes/no)? ",
1142: host);
1143: if (!read_yes_or_no(prompt, -1))
1144: fatal("Aborted by user!\n");
1145: }
1146: /* If not in strict mode, add the key automatically to the local
1147: known_hosts file. */
1148: if (!add_host_to_hostfile(options->user_hostfile, host, host_key.bits,
1149: &host_key.e, &host_key.n))
1150: log("Failed to add the host to the list of known hosts (%.500s).",
1151: options->user_hostfile);
1152: else
1153: log("Warning: Permanently added host '%.200s' to the list of known hosts.", host);
1154: break;
1155: case HOST_CHANGED:
1156: /* The host key has changed. */
1157: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1158: error("@ WARNING: HOST IDENTIFICATION HAS CHANGED! @");
1159: error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1160: error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1161: error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1162: error("It is also possible that the host key has just been changed.");
1163: error("Please contact your system administrator.");
1164: error("Add correct host key in %.100s to get rid of this message.",
1165: options->user_hostfile);
1166:
1167: /* If strict host key checking is in use, the user will have to edit
1168: the key manually and we can only abort. */
1169: if (options->strict_host_key_checking)
1170: fatal("Host key for %.200s has changed and you have requested strict checking.", host);
1171:
1172: /* If strict host key checking has not been requested, allow the
1173: connection but without password authentication. */
1174: error("Password authentication is disabled to avoid trojan horses.");
1175: options->password_authentication = 0;
1176: /* XXX Should permit the user to change to use the new id. This could
1177: be done by converting the host key to an identifying sentence, tell
1178: that the host identifies itself by that sentence, and ask the user
1179: if he/she whishes to accept the authentication. */
1180: break;
1181: }
1182:
1183: /* Generate a session key. */
1184:
1185: /* Initialize the random number generator. */
1186: sprintf(buf, "%.500s/%.200s", pw->pw_dir, SSH_CLIENT_SEEDFILE);
1187: if (stat(buf, &st) < 0)
1188: log("Creating random seed file ~/%.900s. This may take a while.",
1189: SSH_CLIENT_SEEDFILE);
1190: else
1191: debug("Initializing random; seed file %.900s", buf);
1192: random_initialize(state, buf);
1193:
1194: /* Generate an encryption key for the session. The key is a 256 bit
1195: random number, interpreted as a 32-byte key, with the least significant
1196: 8 bits being the first byte of the key. */
1197: for (i = 0; i < 32; i++)
1198: session_key[i] = random_get_byte(state);
1199:
1200: /* Save the new random state. */
1201: random_save(state, buf);
1202: random_stir(state); /* This is supposed to be irreversible. */
1203:
1204: /* According to the protocol spec, the first byte of the session key is
1205: the highest byte of the integer. The session key is xored with the
1206: first 16 bytes of the session id. */
1207: mpz_init_set_ui(&key, 0);
1208: for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++)
1209: {
1210: mpz_mul_2exp(&key, &key, 8);
1211: if (i < 16)
1212: mpz_add_ui(&key, &key, session_key[i] ^ session_id[i]);
1213: else
1214: mpz_add_ui(&key, &key, session_key[i]);
1215: }
1216:
1217: /* Encrypt the integer using the public key and host key of the server
1218: (key with smaller modulus first). */
1219: if (mpz_cmp(&public_key.n, &host_key.n) < 0)
1220: {
1221: /* Public key has smaller modulus. */
1222: assert(host_key.bits >= public_key.bits + SSH_KEY_BITS_RESERVED);
1223:
1224: rsa_public_encrypt(&key, &key, &public_key, state);
1225: rsa_public_encrypt(&key, &key, &host_key, state);
1226: }
1227: else
1228: {
1229: /* Host key has smaller modulus (or they are equal). */
1230: assert(public_key.bits >= host_key.bits + SSH_KEY_BITS_RESERVED);
1231:
1232: rsa_public_encrypt(&key, &key, &host_key, state);
1233: rsa_public_encrypt(&key, &key, &public_key, state);
1234: }
1235:
1236: if (options->cipher == SSH_CIPHER_NOT_SET)
1237: if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default))
1238: options->cipher = ssh_cipher_default;
1239: else
1240: {
1241: debug("Cipher %d not supported, using %.100s instead.",
1242: cipher_name(ssh_cipher_default),
1243: cipher_name(SSH_FALLBACK_CIPHER));
1244: options->cipher = SSH_FALLBACK_CIPHER;
1245: }
1246:
1247: /* Check that the selected cipher is supported. */
1248: if (!(supported_ciphers & (1 << options->cipher)))
1249: fatal("Selected cipher type %.100s not supported by server.",
1250: cipher_name(options->cipher));
1251:
1252: debug("Encryption type: %.100s", cipher_name(options->cipher));
1253:
1254: /* Send the encrypted session key to the server. */
1255: packet_start(SSH_CMSG_SESSION_KEY);
1256: packet_put_char(options->cipher);
1257:
1258: /* Send the check bytes back to the server. */
1259: for (i = 0; i < 8; i++)
1260: packet_put_char(check_bytes[i]);
1261:
1262: /* Send the encrypted encryption key. */
1263: packet_put_mp_int(&key);
1264:
1265: /* Send protocol flags. */
1266: packet_put_int(SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1267:
1268: /* Send the packet now. */
1269: packet_send();
1270: packet_write_wait();
1271:
1272: /* Destroy the session key integer and the public keys since we no longer
1273: need them. */
1274: mpz_clear(&key);
1275: rsa_clear_public_key(&public_key);
1276: rsa_clear_public_key(&host_key);
1277:
1278: debug("Sent encrypted session key.");
1279:
1280: /* Set the encryption key. */
1281: packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH,
1282: options->cipher, 1);
1283:
1284: /* We will no longer need the session key here. Destroy any extra copies. */
1285: memset(session_key, 0, sizeof(session_key));
1286:
1287: /* Expect a success message from the server. Note that this message will
1288: be received in encrypted form. */
1289: packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
1290:
1291: debug("Received encrypted confirmation.");
1292:
1293: /* Send the name of the user to log in as on the server. */
1294: packet_start(SSH_CMSG_USER);
1295: packet_put_string(server_user, strlen(server_user));
1296: packet_send();
1297: packet_write_wait();
1298:
1299: /* The server should respond with success if no authentication is needed
1300: (the user has no password). Otherwise the server responds with
1301: failure. */
1302: type = packet_read(&payload_len);
1303: if (type == SSH_SMSG_SUCCESS)
1304: return; /* Connection was accepted without authentication. */
1305: if (type != SSH_SMSG_FAILURE)
1306: packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER",
1307: type);
1308:
1309: #ifdef KERBEROS_TGT_PASSING
1310: /* Try Kerberos tgt passing if the server supports it. */
1311: if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) &&
1312: options->kerberos_tgt_passing) {
1313: if (options->cipher == SSH_CIPHER_NONE)
1314: log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
1315: (void)send_kerberos_tgt();
1316: }
1317: #endif /* KERBEROS_TGT_PASSING */
1318:
1319: #ifdef AFS
1320: /* Try AFS token passing if the server supports it. */
1321: if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&
1322: options->afs_token_passing && k_hasafs()) {
1323: if (options->cipher == SSH_CIPHER_NONE)
1324: log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");
1325: send_afs_tokens();
1326: }
1327: #endif /* AFS */
1328:
1329: #if defined(KRB4)
1330: if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) &&
1331: options->kerberos_authentication)
1332: {
1333: if (try_kerberos_authentication()) {
1334: /* The server should respond with success or failure. */
1335: type = packet_read(&payload_len);
1336: if (type == SSH_SMSG_SUCCESS)
1337: return; /* Successful connection. */
1338: if (type != SSH_SMSG_FAILURE)
1339: packet_disconnect("Protocol error: got %d in response to Kerberos auth", type);
1340: }
1341: }
1342: #endif /* KRB4 */
1343:
1344: /* Use rhosts authentication if running in privileged socket and we do not
1345: wish to remain anonymous. */
1346: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) &&
1347: options->rhosts_authentication)
1348: {
1349: debug("Trying rhosts authentication.");
1350: packet_start(SSH_CMSG_AUTH_RHOSTS);
1351: packet_put_string(local_user, strlen(local_user));
1352: packet_send();
1353: packet_write_wait();
1354:
1355: /* The server should respond with success or failure. */
1356: type = packet_read(&payload_len);
1357: if (type == SSH_SMSG_SUCCESS)
1358: return; /* Successful connection. */
1359: if (type != SSH_SMSG_FAILURE)
1360: packet_disconnect("Protocol error: got %d in response to rhosts auth",
1361: type);
1362: }
1363:
1364: /* Try .rhosts or /etc/hosts.equiv authentication with RSA host
1365: authentication. */
1366: if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) &&
1367: options->rhosts_rsa_authentication && host_key_valid)
1368: {
1369: if (try_rhosts_rsa_authentication(local_user, own_host_key))
1370: return; /* Successful authentication. */
1371: }
1372:
1373: /* Try RSA authentication if the server supports it. */
1374: if ((supported_authentications & (1 << SSH_AUTH_RSA)) &&
1375: options->rsa_authentication)
1376: {
1377: /* Try RSA authentication using the authentication agent. The agent
1378: is tried first because no passphrase is needed for it, whereas
1379: identity files may require passphrases. */
1380: if (try_agent_authentication())
1381: return; /* Successful connection. */
1382:
1383: /* Try RSA authentication for each identity. */
1384: for (i = 0; i < options->num_identity_files; i++)
1385: if (try_rsa_authentication(pw, options->identity_files[i],
1386: !options->batch_mode))
1387: return; /* Successful connection. */
1388: }
1389:
1390: /* Try password authentication if the server supports it. */
1391: if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) &&
1392: options->password_authentication && !options->batch_mode)
1393: {
1394: debug("Doing password authentication.");
1395: if (options->cipher == SSH_CIPHER_NONE)
1396: log("WARNING: Encryption is disabled! Password will be transmitted in clear text.");
1397: password = read_passphrase("Password: ", 0);
1398: packet_start(SSH_CMSG_AUTH_PASSWORD);
1399: packet_put_string(password, strlen(password));
1400: memset(password, 0, strlen(password));
1401: xfree(password);
1402: packet_send();
1403: packet_write_wait();
1404:
1405: type = packet_read(&payload_len);
1406: if (type == SSH_SMSG_SUCCESS)
1407: return; /* Successful connection. */
1408: if (type != SSH_SMSG_FAILURE)
1409: packet_disconnect("Protocol error: got %d in response to passwd auth",
1410: type);
1411: }
1412:
1413: /* All authentication methods have failed. Exit with an error message. */
1414: fatal("Permission denied.");
1415: /*NOTREACHED*/
1416: }
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