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8efc0c15 | 1 | /* |
5260325f | 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 | */ | |
8efc0c15 | 9 | |
10 | #include "includes.h" | |
7b2ea3a1 | 11 | RCSID("$OpenBSD: sshconnect.c,v 1.53 2000/01/18 09:42:17 markus Exp $"); |
8efc0c15 | 12 | |
5881cd60 | 13 | #ifdef HAVE_OPENSSL |
8efc0c15 | 14 | #include <openssl/bn.h> |
5881cd60 | 15 | #include <openssl/md5.h> |
16 | #endif | |
17 | #ifdef HAVE_SSL | |
18 | #include <ssl/bn.h> | |
19 | #include <ssl/md5.h> | |
20 | #endif | |
21 | ||
8efc0c15 | 22 | #include "xmalloc.h" |
23 | #include "rsa.h" | |
24 | #include "ssh.h" | |
25 | #include "packet.h" | |
26 | #include "authfd.h" | |
27 | #include "cipher.h" | |
28 | #include "mpaux.h" | |
29 | #include "uidswap.h" | |
30 | #include "compat.h" | |
6fa724bc | 31 | #include "readconf.h" |
2bd61362 | 32 | #include "fingerprint.h" |
8efc0c15 | 33 | |
34 | /* Session id for the current session. */ | |
35 | unsigned char session_id[16]; | |
36 | ||
7b2ea3a1 | 37 | /* authentications supported by server */ |
38 | unsigned int supported_authentications; | |
39 | ||
57112b5a | 40 | extern Options options; |
48e671d5 | 41 | extern char *__progname; |
57112b5a | 42 | |
5260325f | 43 | /* |
44 | * Connect to the given ssh server using a proxy command. | |
45 | */ | |
8efc0c15 | 46 | int |
57112b5a | 47 | ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid, |
8efc0c15 | 48 | const char *proxy_command) |
49 | { | |
5260325f | 50 | Buffer command; |
51 | const char *cp; | |
52 | char *command_string; | |
53 | int pin[2], pout[2]; | |
54 | int pid; | |
48e671d5 | 55 | char strport[NI_MAXSERV]; |
5260325f | 56 | |
57 | /* Convert the port number into a string. */ | |
48e671d5 | 58 | snprintf(strport, sizeof strport, "%hu", port); |
5260325f | 59 | |
60 | /* Build the final command string in the buffer by making the | |
61 | appropriate substitutions to the given proxy command. */ | |
62 | buffer_init(&command); | |
63 | for (cp = proxy_command; *cp; cp++) { | |
64 | if (cp[0] == '%' && cp[1] == '%') { | |
65 | buffer_append(&command, "%", 1); | |
66 | cp++; | |
67 | continue; | |
68 | } | |
69 | if (cp[0] == '%' && cp[1] == 'h') { | |
70 | buffer_append(&command, host, strlen(host)); | |
71 | cp++; | |
72 | continue; | |
73 | } | |
74 | if (cp[0] == '%' && cp[1] == 'p') { | |
48e671d5 | 75 | buffer_append(&command, strport, strlen(strport)); |
5260325f | 76 | cp++; |
77 | continue; | |
78 | } | |
79 | buffer_append(&command, cp, 1); | |
8efc0c15 | 80 | } |
5260325f | 81 | buffer_append(&command, "\0", 1); |
82 | ||
83 | /* Get the final command string. */ | |
84 | command_string = buffer_ptr(&command); | |
85 | ||
86 | /* Create pipes for communicating with the proxy. */ | |
87 | if (pipe(pin) < 0 || pipe(pout) < 0) | |
88 | fatal("Could not create pipes to communicate with the proxy: %.100s", | |
89 | strerror(errno)); | |
90 | ||
91 | debug("Executing proxy command: %.500s", command_string); | |
92 | ||
93 | /* Fork and execute the proxy command. */ | |
94 | if ((pid = fork()) == 0) { | |
95 | char *argv[10]; | |
96 | ||
97 | /* Child. Permanently give up superuser privileges. */ | |
98 | permanently_set_uid(original_real_uid); | |
99 | ||
100 | /* Redirect stdin and stdout. */ | |
101 | close(pin[1]); | |
102 | if (pin[0] != 0) { | |
103 | if (dup2(pin[0], 0) < 0) | |
104 | perror("dup2 stdin"); | |
105 | close(pin[0]); | |
106 | } | |
107 | close(pout[0]); | |
108 | if (dup2(pout[1], 1) < 0) | |
109 | perror("dup2 stdout"); | |
110 | /* Cannot be 1 because pin allocated two descriptors. */ | |
111 | close(pout[1]); | |
112 | ||
113 | /* Stderr is left as it is so that error messages get | |
114 | printed on the user's terminal. */ | |
115 | argv[0] = "/bin/sh"; | |
116 | argv[1] = "-c"; | |
117 | argv[2] = command_string; | |
118 | argv[3] = NULL; | |
119 | ||
120 | /* Execute the proxy command. Note that we gave up any | |
121 | extra privileges above. */ | |
122 | execv("/bin/sh", argv); | |
123 | perror("/bin/sh"); | |
124 | exit(1); | |
8efc0c15 | 125 | } |
5260325f | 126 | /* Parent. */ |
127 | if (pid < 0) | |
128 | fatal("fork failed: %.100s", strerror(errno)); | |
129 | ||
130 | /* Close child side of the descriptors. */ | |
131 | close(pin[0]); | |
132 | close(pout[1]); | |
133 | ||
134 | /* Free the command name. */ | |
135 | buffer_free(&command); | |
136 | ||
137 | /* Set the connection file descriptors. */ | |
138 | packet_set_connection(pout[0], pin[1]); | |
8efc0c15 | 139 | |
5260325f | 140 | return 1; |
141 | } | |
8efc0c15 | 142 | |
5260325f | 143 | /* |
144 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
145 | */ | |
146 | int | |
48e671d5 | 147 | ssh_create_socket(uid_t original_real_uid, int privileged, int family) |
8efc0c15 | 148 | { |
5260325f | 149 | int sock; |
150 | ||
aa3378df | 151 | /* |
152 | * If we are running as root and want to connect to a privileged | |
153 | * port, bind our own socket to a privileged port. | |
154 | */ | |
5260325f | 155 | if (privileged) { |
156 | int p = IPPORT_RESERVED - 1; | |
48e671d5 | 157 | sock = rresvport_af(&p, family); |
5260325f | 158 | if (sock < 0) |
48e671d5 | 159 | fatal("rresvport: af=%d %.100s", family, strerror(errno)); |
5260325f | 160 | debug("Allocated local port %d.", p); |
161 | } else { | |
95f1eccc | 162 | /* |
163 | * Just create an ordinary socket on arbitrary port. We use | |
164 | * the user's uid to create the socket. | |
165 | */ | |
5260325f | 166 | temporarily_use_uid(original_real_uid); |
48e671d5 | 167 | sock = socket(family, SOCK_STREAM, 0); |
5260325f | 168 | if (sock < 0) |
48e671d5 | 169 | error("socket: %.100s", strerror(errno)); |
5260325f | 170 | restore_uid(); |
171 | } | |
172 | return sock; | |
8efc0c15 | 173 | } |
174 | ||
5260325f | 175 | /* |
48e671d5 | 176 | * Opens a TCP/IP connection to the remote server on the given host. |
177 | * The address of the remote host will be returned in hostaddr. | |
178 | * If port is 0, the default port will be used. If anonymous is zero, | |
5260325f | 179 | * a privileged port will be allocated to make the connection. |
180 | * This requires super-user privileges if anonymous is false. | |
181 | * Connection_attempts specifies the maximum number of tries (one per | |
182 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
183 | * and %p substituted for host and port, respectively) to use to contact | |
184 | * the daemon. | |
185 | */ | |
186 | int | |
48e671d5 | 187 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
57112b5a | 188 | u_short port, int connection_attempts, |
5260325f | 189 | int anonymous, uid_t original_real_uid, |
190 | const char *proxy_command) | |
8efc0c15 | 191 | { |
48e671d5 | 192 | int sock = -1, attempt; |
5260325f | 193 | struct servent *sp; |
48e671d5 | 194 | struct addrinfo hints, *ai, *aitop; |
195 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
196 | int gaierr; | |
5260325f | 197 | struct linger linger; |
198 | ||
199 | debug("ssh_connect: getuid %d geteuid %d anon %d", | |
200 | (int) getuid(), (int) geteuid(), anonymous); | |
201 | ||
202 | /* Get default port if port has not been set. */ | |
203 | if (port == 0) { | |
204 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); | |
205 | if (sp) | |
206 | port = ntohs(sp->s_port); | |
207 | else | |
208 | port = SSH_DEFAULT_PORT; | |
8efc0c15 | 209 | } |
5260325f | 210 | /* If a proxy command is given, connect using it. */ |
211 | if (proxy_command != NULL) | |
212 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); | |
213 | ||
214 | /* No proxy command. */ | |
215 | ||
48e671d5 | 216 | memset(&hints, 0, sizeof(hints)); |
217 | hints.ai_family = IPv4or6; | |
218 | hints.ai_socktype = SOCK_STREAM; | |
219 | snprintf(strport, sizeof strport, "%d", port); | |
220 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) | |
221 | fatal("%s: %.100s: %s", __progname, host, | |
222 | gai_strerror(gaierr)); | |
5260325f | 223 | |
95f1eccc | 224 | /* |
225 | * Try to connect several times. On some machines, the first time | |
226 | * will sometimes fail. In general socket code appears to behave | |
227 | * quite magically on many machines. | |
228 | */ | |
5260325f | 229 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
230 | if (attempt > 0) | |
231 | debug("Trying again..."); | |
232 | ||
48e671d5 | 233 | /* Loop through addresses for this host, and try each one in |
234 | sequence until the connection succeeds. */ | |
235 | for (ai = aitop; ai; ai = ai->ai_next) { | |
236 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
237 | continue; | |
238 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
239 | ntop, sizeof(ntop), strport, sizeof(strport), | |
240 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
241 | error("ssh_connect: getnameinfo failed"); | |
242 | continue; | |
243 | } | |
244 | debug("Connecting to %.200s [%.100s] port %s.", | |
245 | host, ntop, strport); | |
246 | ||
247 | /* Create a socket for connecting. */ | |
248 | sock = ssh_create_socket(original_real_uid, | |
249 | !anonymous && geteuid() == 0 && port < IPPORT_RESERVED, | |
250 | ai->ai_family); | |
251 | if (sock < 0) | |
252 | continue; | |
253 | ||
254 | /* Connect to the host. We use the user's uid in the | |
255 | * hope that it will help with tcp_wrappers showing | |
256 | * the remote uid as root. | |
aa3378df | 257 | */ |
5260325f | 258 | temporarily_use_uid(original_real_uid); |
48e671d5 | 259 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { |
260 | /* Successful connection. */ | |
261 | memcpy(hostaddr, ai->ai_addr, sizeof(*(ai->ai_addr))); | |
5260325f | 262 | restore_uid(); |
263 | break; | |
48e671d5 | 264 | } else { |
5260325f | 265 | debug("connect: %.100s", strerror(errno)); |
266 | restore_uid(); | |
aa3378df | 267 | /* |
268 | * Close the failed socket; there appear to | |
269 | * be some problems when reusing a socket for | |
270 | * which connect() has already returned an | |
271 | * error. | |
272 | */ | |
5260325f | 273 | shutdown(sock, SHUT_RDWR); |
274 | close(sock); | |
275 | } | |
8efc0c15 | 276 | } |
48e671d5 | 277 | if (ai) |
278 | break; /* Successful connection. */ | |
8efc0c15 | 279 | |
5260325f | 280 | /* Sleep a moment before retrying. */ |
281 | sleep(1); | |
282 | } | |
48e671d5 | 283 | |
284 | freeaddrinfo(aitop); | |
285 | ||
5260325f | 286 | /* Return failure if we didn't get a successful connection. */ |
287 | if (attempt >= connection_attempts) | |
288 | return 0; | |
8efc0c15 | 289 | |
5260325f | 290 | debug("Connection established."); |
8efc0c15 | 291 | |
aa3378df | 292 | /* |
293 | * Set socket options. We would like the socket to disappear as soon | |
294 | * as it has been closed for whatever reason. | |
295 | */ | |
296 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 297 | linger.l_onoff = 1; |
298 | linger.l_linger = 5; | |
299 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
8efc0c15 | 300 | |
5260325f | 301 | /* Set the connection. */ |
302 | packet_set_connection(sock, sock); | |
8efc0c15 | 303 | |
5260325f | 304 | return 1; |
8efc0c15 | 305 | } |
306 | ||
5260325f | 307 | /* |
308 | * Checks if the user has an authentication agent, and if so, tries to | |
309 | * authenticate using the agent. | |
310 | */ | |
8efc0c15 | 311 | int |
312 | try_agent_authentication() | |
313 | { | |
5260325f | 314 | int status, type; |
315 | char *comment; | |
316 | AuthenticationConnection *auth; | |
317 | unsigned char response[16]; | |
318 | unsigned int i; | |
319 | BIGNUM *e, *n, *challenge; | |
320 | ||
321 | /* Get connection to the agent. */ | |
322 | auth = ssh_get_authentication_connection(); | |
323 | if (!auth) | |
324 | return 0; | |
325 | ||
326 | e = BN_new(); | |
327 | n = BN_new(); | |
328 | challenge = BN_new(); | |
329 | ||
330 | /* Loop through identities served by the agent. */ | |
331 | for (status = ssh_get_first_identity(auth, e, n, &comment); | |
332 | status; | |
333 | status = ssh_get_next_identity(auth, e, n, &comment)) { | |
334 | int plen, clen; | |
335 | ||
336 | /* Try this identity. */ | |
337 | debug("Trying RSA authentication via agent with '%.100s'", comment); | |
338 | xfree(comment); | |
339 | ||
340 | /* Tell the server that we are willing to authenticate using this key. */ | |
341 | packet_start(SSH_CMSG_AUTH_RSA); | |
342 | packet_put_bignum(n); | |
343 | packet_send(); | |
344 | packet_write_wait(); | |
345 | ||
346 | /* Wait for server's response. */ | |
347 | type = packet_read(&plen); | |
348 | ||
349 | /* The server sends failure if it doesn\'t like our key or | |
350 | does not support RSA authentication. */ | |
351 | if (type == SSH_SMSG_FAILURE) { | |
352 | debug("Server refused our key."); | |
353 | continue; | |
354 | } | |
355 | /* Otherwise it should have sent a challenge. */ | |
356 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
357 | packet_disconnect("Protocol error during RSA authentication: %d", | |
358 | type); | |
8efc0c15 | 359 | |
5260325f | 360 | packet_get_bignum(challenge, &clen); |
8efc0c15 | 361 | |
5260325f | 362 | packet_integrity_check(plen, clen, type); |
8efc0c15 | 363 | |
5260325f | 364 | debug("Received RSA challenge from server."); |
365 | ||
366 | /* Ask the agent to decrypt the challenge. */ | |
367 | if (!ssh_decrypt_challenge(auth, e, n, challenge, | |
368 | session_id, 1, response)) { | |
369 | /* The agent failed to authenticate this identifier although it | |
370 | advertised it supports this. Just return a wrong value. */ | |
371 | log("Authentication agent failed to decrypt challenge."); | |
372 | memset(response, 0, sizeof(response)); | |
373 | } | |
374 | debug("Sending response to RSA challenge."); | |
375 | ||
376 | /* Send the decrypted challenge back to the server. */ | |
377 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
378 | for (i = 0; i < 16; i++) | |
379 | packet_put_char(response[i]); | |
380 | packet_send(); | |
381 | packet_write_wait(); | |
382 | ||
383 | /* Wait for response from the server. */ | |
384 | type = packet_read(&plen); | |
385 | ||
386 | /* The server returns success if it accepted the authentication. */ | |
387 | if (type == SSH_SMSG_SUCCESS) { | |
388 | debug("RSA authentication accepted by server."); | |
389 | BN_clear_free(e); | |
390 | BN_clear_free(n); | |
391 | BN_clear_free(challenge); | |
392 | return 1; | |
393 | } | |
394 | /* Otherwise it should return failure. */ | |
395 | if (type != SSH_SMSG_FAILURE) | |
396 | packet_disconnect("Protocol error waiting RSA auth response: %d", | |
397 | type); | |
398 | } | |
399 | ||
400 | BN_clear_free(e); | |
401 | BN_clear_free(n); | |
402 | BN_clear_free(challenge); | |
8efc0c15 | 403 | |
5260325f | 404 | debug("RSA authentication using agent refused."); |
405 | return 0; | |
406 | } | |
8efc0c15 | 407 | |
5260325f | 408 | /* |
409 | * Computes the proper response to a RSA challenge, and sends the response to | |
410 | * the server. | |
411 | */ | |
8efc0c15 | 412 | void |
5260325f | 413 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
8efc0c15 | 414 | { |
5260325f | 415 | unsigned char buf[32], response[16]; |
416 | MD5_CTX md; | |
417 | int i, len; | |
418 | ||
419 | /* Decrypt the challenge using the private key. */ | |
420 | rsa_private_decrypt(challenge, challenge, prv); | |
421 | ||
422 | /* Compute the response. */ | |
423 | /* The response is MD5 of decrypted challenge plus session id. */ | |
424 | len = BN_num_bytes(challenge); | |
425 | if (len <= 0 || len > sizeof(buf)) | |
426 | packet_disconnect("respond_to_rsa_challenge: bad challenge length %d", | |
427 | len); | |
428 | ||
429 | memset(buf, 0, sizeof(buf)); | |
430 | BN_bn2bin(challenge, buf + sizeof(buf) - len); | |
431 | MD5_Init(&md); | |
432 | MD5_Update(&md, buf, 32); | |
433 | MD5_Update(&md, session_id, 16); | |
434 | MD5_Final(response, &md); | |
435 | ||
436 | debug("Sending response to host key RSA challenge."); | |
437 | ||
438 | /* Send the response back to the server. */ | |
439 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
440 | for (i = 0; i < 16; i++) | |
441 | packet_put_char(response[i]); | |
442 | packet_send(); | |
443 | packet_write_wait(); | |
8efc0c15 | 444 | |
5260325f | 445 | memset(buf, 0, sizeof(buf)); |
446 | memset(response, 0, sizeof(response)); | |
447 | memset(&md, 0, sizeof(md)); | |
448 | } | |
8efc0c15 | 449 | |
5260325f | 450 | /* |
451 | * Checks if the user has authentication file, and if so, tries to authenticate | |
452 | * the user using it. | |
453 | */ | |
8efc0c15 | 454 | int |
57112b5a | 455 | try_rsa_authentication(const char *authfile) |
8efc0c15 | 456 | { |
5260325f | 457 | BIGNUM *challenge; |
458 | RSA *private_key; | |
459 | RSA *public_key; | |
460 | char *passphrase, *comment; | |
461 | int type, i; | |
462 | int plen, clen; | |
463 | ||
464 | /* Try to load identification for the authentication key. */ | |
465 | public_key = RSA_new(); | |
466 | if (!load_public_key(authfile, public_key, &comment)) { | |
467 | RSA_free(public_key); | |
57112b5a | 468 | /* Could not load it. Fail. */ |
469 | return 0; | |
8efc0c15 | 470 | } |
5260325f | 471 | debug("Trying RSA authentication with key '%.100s'", comment); |
472 | ||
473 | /* Tell the server that we are willing to authenticate using this key. */ | |
474 | packet_start(SSH_CMSG_AUTH_RSA); | |
475 | packet_put_bignum(public_key->n); | |
476 | packet_send(); | |
477 | packet_write_wait(); | |
478 | ||
479 | /* We no longer need the public key. */ | |
480 | RSA_free(public_key); | |
481 | ||
482 | /* Wait for server's response. */ | |
483 | type = packet_read(&plen); | |
484 | ||
aa3378df | 485 | /* |
486 | * The server responds with failure if it doesn\'t like our key or | |
487 | * doesn\'t support RSA authentication. | |
488 | */ | |
5260325f | 489 | if (type == SSH_SMSG_FAILURE) { |
490 | debug("Server refused our key."); | |
491 | xfree(comment); | |
57112b5a | 492 | return 0; |
8efc0c15 | 493 | } |
5260325f | 494 | /* Otherwise, the server should respond with a challenge. */ |
495 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
496 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
497 | ||
498 | /* Get the challenge from the packet. */ | |
499 | challenge = BN_new(); | |
500 | packet_get_bignum(challenge, &clen); | |
501 | ||
502 | packet_integrity_check(plen, clen, type); | |
503 | ||
504 | debug("Received RSA challenge from server."); | |
505 | ||
506 | private_key = RSA_new(); | |
aa3378df | 507 | /* |
508 | * Load the private key. Try first with empty passphrase; if it | |
509 | * fails, ask for a passphrase. | |
510 | */ | |
5260325f | 511 | if (!load_private_key(authfile, "", private_key, NULL)) { |
512 | char buf[300]; | |
513 | snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ", | |
a408af76 | 514 | comment); |
5260325f | 515 | if (!options.batch_mode) |
516 | passphrase = read_passphrase(buf, 0); | |
517 | else { | |
518 | debug("Will not query passphrase for %.100s in batch mode.", | |
519 | comment); | |
520 | passphrase = xstrdup(""); | |
521 | } | |
8efc0c15 | 522 | |
5260325f | 523 | /* Load the authentication file using the pasphrase. */ |
524 | if (!load_private_key(authfile, passphrase, private_key, NULL)) { | |
525 | memset(passphrase, 0, strlen(passphrase)); | |
526 | xfree(passphrase); | |
527 | error("Bad passphrase."); | |
528 | ||
529 | /* Send a dummy response packet to avoid protocol error. */ | |
530 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
531 | for (i = 0; i < 16; i++) | |
532 | packet_put_char(0); | |
533 | packet_send(); | |
534 | packet_write_wait(); | |
535 | ||
536 | /* Expect the server to reject it... */ | |
537 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
538 | xfree(comment); | |
539 | return 0; | |
540 | } | |
541 | /* Destroy the passphrase. */ | |
542 | memset(passphrase, 0, strlen(passphrase)); | |
543 | xfree(passphrase); | |
544 | } | |
545 | /* We no longer need the comment. */ | |
546 | xfree(comment); | |
547 | ||
548 | /* Compute and send a response to the challenge. */ | |
549 | respond_to_rsa_challenge(challenge, private_key); | |
550 | ||
551 | /* Destroy the private key. */ | |
552 | RSA_free(private_key); | |
8efc0c15 | 553 | |
5260325f | 554 | /* We no longer need the challenge. */ |
555 | BN_clear_free(challenge); | |
556 | ||
557 | /* Wait for response from the server. */ | |
558 | type = packet_read(&plen); | |
559 | if (type == SSH_SMSG_SUCCESS) { | |
560 | debug("RSA authentication accepted by server."); | |
561 | return 1; | |
562 | } | |
563 | if (type != SSH_SMSG_FAILURE) | |
564 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
565 | debug("RSA authentication refused."); | |
566 | return 0; | |
567 | } | |
8efc0c15 | 568 | |
5260325f | 569 | /* |
570 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
571 | * authentication and RSA host authentication. | |
572 | */ | |
8efc0c15 | 573 | int |
5260325f | 574 | try_rhosts_rsa_authentication(const char *local_user, RSA * host_key) |
8efc0c15 | 575 | { |
5260325f | 576 | int type; |
577 | BIGNUM *challenge; | |
578 | int plen, clen; | |
579 | ||
580 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
581 | ||
582 | /* Tell the server that we are willing to authenticate using this key. */ | |
583 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
584 | packet_put_string(local_user, strlen(local_user)); | |
585 | packet_put_int(BN_num_bits(host_key->n)); | |
586 | packet_put_bignum(host_key->e); | |
587 | packet_put_bignum(host_key->n); | |
588 | packet_send(); | |
589 | packet_write_wait(); | |
590 | ||
591 | /* Wait for server's response. */ | |
592 | type = packet_read(&plen); | |
593 | ||
594 | /* The server responds with failure if it doesn't admit our | |
595 | .rhosts authentication or doesn't know our host key. */ | |
596 | if (type == SSH_SMSG_FAILURE) { | |
597 | debug("Server refused our rhosts authentication or host key."); | |
598 | return 0; | |
599 | } | |
600 | /* Otherwise, the server should respond with a challenge. */ | |
601 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
602 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
603 | ||
604 | /* Get the challenge from the packet. */ | |
605 | challenge = BN_new(); | |
606 | packet_get_bignum(challenge, &clen); | |
607 | ||
608 | packet_integrity_check(plen, clen, type); | |
609 | ||
610 | debug("Received RSA challenge for host key from server."); | |
611 | ||
612 | /* Compute a response to the challenge. */ | |
613 | respond_to_rsa_challenge(challenge, host_key); | |
614 | ||
615 | /* We no longer need the challenge. */ | |
616 | BN_clear_free(challenge); | |
617 | ||
618 | /* Wait for response from the server. */ | |
619 | type = packet_read(&plen); | |
620 | if (type == SSH_SMSG_SUCCESS) { | |
621 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
622 | return 1; | |
623 | } | |
624 | if (type != SSH_SMSG_FAILURE) | |
625 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
626 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
627 | return 0; | |
8efc0c15 | 628 | } |
629 | ||
630 | #ifdef KRB4 | |
5260325f | 631 | int |
632 | try_kerberos_authentication() | |
8efc0c15 | 633 | { |
5260325f | 634 | KTEXT_ST auth; /* Kerberos data */ |
635 | char *reply; | |
636 | char inst[INST_SZ]; | |
637 | char *realm; | |
638 | CREDENTIALS cred; | |
639 | int r, type, plen; | |
640 | Key_schedule schedule; | |
641 | u_long checksum, cksum; | |
642 | MSG_DAT msg_data; | |
643 | struct sockaddr_in local, foreign; | |
644 | struct stat st; | |
645 | ||
646 | /* Don't do anything if we don't have any tickets. */ | |
647 | if (stat(tkt_string(), &st) < 0) | |
648 | return 0; | |
649 | ||
650 | strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ); | |
651 | ||
652 | realm = (char *) krb_realmofhost(get_canonical_hostname()); | |
653 | if (!realm) { | |
654 | debug("Kerberos V4: no realm for %s", get_canonical_hostname()); | |
655 | return 0; | |
656 | } | |
657 | /* This can really be anything. */ | |
658 | checksum = (u_long) getpid(); | |
659 | ||
660 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); | |
661 | if (r != KSUCCESS) { | |
662 | debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]); | |
663 | return 0; | |
664 | } | |
665 | /* Get session key to decrypt the server's reply with. */ | |
666 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
667 | if (r != KSUCCESS) { | |
668 | debug("get_cred failed: %s", krb_err_txt[r]); | |
669 | return 0; | |
670 | } | |
671 | des_key_sched((des_cblock *) cred.session, schedule); | |
672 | ||
673 | /* Send authentication info to server. */ | |
674 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
675 | packet_put_string((char *) auth.dat, auth.length); | |
676 | packet_send(); | |
677 | packet_write_wait(); | |
678 | ||
679 | /* Zero the buffer. */ | |
680 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
681 | ||
682 | r = sizeof(local); | |
683 | memset(&local, 0, sizeof(local)); | |
684 | if (getsockname(packet_get_connection_in(), | |
685 | (struct sockaddr *) & local, &r) < 0) | |
686 | debug("getsockname failed: %s", strerror(errno)); | |
687 | ||
688 | r = sizeof(foreign); | |
689 | memset(&foreign, 0, sizeof(foreign)); | |
690 | if (getpeername(packet_get_connection_in(), | |
691 | (struct sockaddr *) & foreign, &r) < 0) { | |
692 | debug("getpeername failed: %s", strerror(errno)); | |
693 | fatal_cleanup(); | |
694 | } | |
695 | /* Get server reply. */ | |
696 | type = packet_read(&plen); | |
697 | switch (type) { | |
698 | case SSH_SMSG_FAILURE: | |
699 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
700 | debug("Kerberos V4 authentication failed."); | |
701 | return 0; | |
702 | break; | |
703 | ||
704 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
705 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
706 | debug("Kerberos V4 authentication accepted."); | |
707 | ||
708 | /* Get server's response. */ | |
709 | reply = packet_get_string((unsigned int *) &auth.length); | |
710 | memcpy(auth.dat, reply, auth.length); | |
711 | xfree(reply); | |
712 | ||
713 | packet_integrity_check(plen, 4 + auth.length, type); | |
714 | ||
aa3378df | 715 | /* |
716 | * If his response isn't properly encrypted with the session | |
717 | * key, and the decrypted checksum fails to match, he's | |
718 | * bogus. Bail out. | |
719 | */ | |
5260325f | 720 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, |
721 | &foreign, &local, &msg_data); | |
722 | if (r != KSUCCESS) { | |
723 | debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]); | |
724 | packet_disconnect("Kerberos V4 challenge failed!"); | |
725 | } | |
726 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
727 | (void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum)); | |
728 | cksum = ntohl(cksum); | |
729 | ||
730 | /* If it matches, we're golden. */ | |
731 | if (cksum == checksum + 1) { | |
732 | debug("Kerberos V4 challenge successful."); | |
733 | return 1; | |
734 | } else | |
735 | packet_disconnect("Kerberos V4 challenge failed!"); | |
736 | break; | |
737 | ||
738 | default: | |
739 | packet_disconnect("Protocol error on Kerberos V4 response: %d", type); | |
740 | } | |
741 | return 0; | |
8efc0c15 | 742 | } |
5260325f | 743 | |
8efc0c15 | 744 | #endif /* KRB4 */ |
745 | ||
746 | #ifdef AFS | |
5260325f | 747 | int |
748 | send_kerberos_tgt() | |
8efc0c15 | 749 | { |
5260325f | 750 | CREDENTIALS *creds; |
751 | char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; | |
752 | int r, type, plen; | |
753 | unsigned char buffer[8192]; | |
754 | struct stat st; | |
755 | ||
756 | /* Don't do anything if we don't have any tickets. */ | |
757 | if (stat(tkt_string(), &st) < 0) | |
758 | return 0; | |
759 | ||
760 | creds = xmalloc(sizeof(*creds)); | |
761 | ||
762 | if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) { | |
763 | debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]); | |
764 | return 0; | |
765 | } | |
766 | if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) { | |
767 | debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]); | |
768 | return 0; | |
769 | } | |
770 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { | |
771 | debug("Kerberos V4 ticket expired: %s", TKT_FILE); | |
772 | return 0; | |
773 | } | |
774 | creds_to_radix(creds, buffer); | |
775 | xfree(creds); | |
776 | ||
777 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
778 | packet_put_string((char *) buffer, strlen(buffer)); | |
779 | packet_send(); | |
780 | packet_write_wait(); | |
781 | ||
782 | type = packet_read(&plen); | |
783 | ||
784 | if (type == SSH_SMSG_FAILURE) | |
785 | debug("Kerberos TGT for realm %s rejected.", prealm); | |
786 | else if (type != SSH_SMSG_SUCCESS) | |
787 | packet_disconnect("Protocol error on Kerberos TGT response: %d", type); | |
788 | ||
789 | return 1; | |
8efc0c15 | 790 | } |
791 | ||
5260325f | 792 | void |
793 | send_afs_tokens(void) | |
8efc0c15 | 794 | { |
5260325f | 795 | CREDENTIALS creds; |
796 | struct ViceIoctl parms; | |
797 | struct ClearToken ct; | |
798 | int i, type, len, plen; | |
799 | char buf[2048], *p, *server_cell; | |
800 | unsigned char buffer[8192]; | |
801 | ||
802 | /* Move over ktc_GetToken, here's something leaner. */ | |
803 | for (i = 0; i < 100; i++) { /* just in case */ | |
804 | parms.in = (char *) &i; | |
805 | parms.in_size = sizeof(i); | |
806 | parms.out = buf; | |
807 | parms.out_size = sizeof(buf); | |
808 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
809 | break; | |
810 | p = buf; | |
811 | ||
812 | /* Get secret token. */ | |
813 | memcpy(&creds.ticket_st.length, p, sizeof(unsigned int)); | |
814 | if (creds.ticket_st.length > MAX_KTXT_LEN) | |
815 | break; | |
816 | p += sizeof(unsigned int); | |
817 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); | |
818 | p += creds.ticket_st.length; | |
819 | ||
820 | /* Get clear token. */ | |
821 | memcpy(&len, p, sizeof(len)); | |
822 | if (len != sizeof(struct ClearToken)) | |
823 | break; | |
824 | p += sizeof(len); | |
825 | memcpy(&ct, p, len); | |
826 | p += len; | |
827 | p += sizeof(len); /* primary flag */ | |
828 | server_cell = p; | |
829 | ||
830 | /* Flesh out our credentials. */ | |
831 | strlcpy(creds.service, "afs", sizeof creds.service); | |
832 | creds.instance[0] = '\0'; | |
833 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
834 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
835 | creds.issue_date = ct.BeginTimestamp; | |
836 | creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp); | |
837 | creds.kvno = ct.AuthHandle; | |
838 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
839 | creds.pinst[0] = '\0'; | |
840 | ||
841 | /* Encode token, ship it off. */ | |
842 | if (!creds_to_radix(&creds, buffer)) | |
843 | break; | |
844 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
845 | packet_put_string((char *) buffer, strlen(buffer)); | |
846 | packet_send(); | |
847 | packet_write_wait(); | |
848 | ||
849 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
850 | Victor? */ | |
851 | type = packet_read(&plen); | |
852 | ||
853 | if (type == SSH_SMSG_FAILURE) | |
854 | debug("AFS token for cell %s rejected.", server_cell); | |
855 | else if (type != SSH_SMSG_SUCCESS) | |
856 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
857 | } | |
8efc0c15 | 858 | } |
8efc0c15 | 859 | |
5260325f | 860 | #endif /* AFS */ |
8efc0c15 | 861 | |
57112b5a | 862 | /* |
863 | * Tries to authenticate with any string-based challenge/response system. | |
864 | * Note that the client code is not tied to s/key or TIS. | |
865 | */ | |
866 | int | |
867 | try_skey_authentication() | |
868 | { | |
869 | int type, i, payload_len; | |
870 | char *challenge, *response; | |
871 | ||
872 | debug("Doing skey authentication."); | |
873 | ||
874 | /* request a challenge */ | |
875 | packet_start(SSH_CMSG_AUTH_TIS); | |
876 | packet_send(); | |
877 | packet_write_wait(); | |
878 | ||
879 | type = packet_read(&payload_len); | |
880 | if (type != SSH_SMSG_FAILURE && | |
881 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
882 | packet_disconnect("Protocol error: got %d in response " | |
883 | "to skey-auth", type); | |
884 | } | |
885 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
886 | debug("No challenge for skey authentication."); | |
887 | return 0; | |
888 | } | |
889 | challenge = packet_get_string(&payload_len); | |
890 | if (options.cipher == SSH_CIPHER_NONE) | |
891 | log("WARNING: Encryption is disabled! " | |
892 | "Reponse will be transmitted in clear text."); | |
893 | fprintf(stderr, "%s\n", challenge); | |
894 | fflush(stderr); | |
895 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
896 | if (i != 0) | |
897 | error("Permission denied, please try again."); | |
898 | response = read_passphrase("Response: ", 0); | |
899 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); | |
900 | packet_put_string(response, strlen(response)); | |
901 | memset(response, 0, strlen(response)); | |
902 | xfree(response); | |
903 | packet_send(); | |
904 | packet_write_wait(); | |
905 | type = packet_read(&payload_len); | |
906 | if (type == SSH_SMSG_SUCCESS) | |
907 | return 1; | |
908 | if (type != SSH_SMSG_FAILURE) | |
909 | packet_disconnect("Protocol error: got %d in response " | |
910 | "to skey-auth-reponse", type); | |
911 | } | |
912 | /* failure */ | |
913 | return 0; | |
914 | } | |
915 | ||
916 | /* | |
917 | * Tries to authenticate with plain passwd authentication. | |
918 | */ | |
919 | int | |
920 | try_password_authentication(char *prompt) | |
921 | { | |
922 | int type, i, payload_len; | |
923 | char *password; | |
924 | ||
925 | debug("Doing password authentication."); | |
926 | if (options.cipher == SSH_CIPHER_NONE) | |
927 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
928 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
929 | if (i != 0) | |
930 | error("Permission denied, please try again."); | |
931 | password = read_passphrase(prompt, 0); | |
932 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
933 | packet_put_string(password, strlen(password)); | |
934 | memset(password, 0, strlen(password)); | |
935 | xfree(password); | |
936 | packet_send(); | |
937 | packet_write_wait(); | |
938 | ||
939 | type = packet_read(&payload_len); | |
940 | if (type == SSH_SMSG_SUCCESS) | |
941 | return 1; | |
942 | if (type != SSH_SMSG_FAILURE) | |
943 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
944 | } | |
945 | /* failure */ | |
946 | return 0; | |
947 | } | |
948 | ||
5260325f | 949 | /* |
950 | * Waits for the server identification string, and sends our own | |
951 | * identification string. | |
952 | */ | |
953 | void | |
954 | ssh_exchange_identification() | |
8efc0c15 | 955 | { |
5260325f | 956 | char buf[256], remote_version[256]; /* must be same size! */ |
957 | int remote_major, remote_minor, i; | |
958 | int connection_in = packet_get_connection_in(); | |
959 | int connection_out = packet_get_connection_out(); | |
5260325f | 960 | |
961 | /* Read other side\'s version identification. */ | |
962 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
963 | if (read(connection_in, &buf[i], 1) != 1) | |
964 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); | |
965 | if (buf[i] == '\r') { | |
966 | buf[i] = '\n'; | |
967 | buf[i + 1] = 0; | |
968 | break; | |
969 | } | |
970 | if (buf[i] == '\n') { | |
971 | buf[i + 1] = 0; | |
972 | break; | |
973 | } | |
8efc0c15 | 974 | } |
5260325f | 975 | buf[sizeof(buf) - 1] = 0; |
976 | ||
aa3378df | 977 | /* |
978 | * Check that the versions match. In future this might accept | |
979 | * several versions and set appropriate flags to handle them. | |
980 | */ | |
5260325f | 981 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
982 | remote_version) != 3) | |
983 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
984 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
985 | remote_major, remote_minor, remote_version); | |
986 | ||
987 | /* Check if the remote protocol version is too old. */ | |
988 | if (remote_major == 1 && remote_minor < 3) | |
989 | fatal("Remote machine has too old SSH software version."); | |
990 | ||
991 | /* We speak 1.3, too. */ | |
992 | if (remote_major == 1 && remote_minor == 3) { | |
993 | enable_compat13(); | |
7b2ea3a1 | 994 | if (options.forward_agent) { |
995 | log("Agent forwarding disabled for protocol 1.3"); | |
5260325f | 996 | options.forward_agent = 0; |
997 | } | |
8efc0c15 | 998 | } |
8efc0c15 | 999 | #if 0 |
aa3378df | 1000 | /* |
1001 | * Removed for now, to permit compatibility with latter versions. The | |
1002 | * server will reject our version and disconnect if it doesn't | |
1003 | * support it. | |
1004 | */ | |
5260325f | 1005 | if (remote_major != PROTOCOL_MAJOR) |
1006 | fatal("Protocol major versions differ: %d vs. %d", | |
1007 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 1008 | #endif |
1009 | ||
5260325f | 1010 | /* Send our own protocol version identification. */ |
1011 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
a408af76 | 1012 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); |
1013 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) | |
5260325f | 1014 | fatal("write: %.100s", strerror(errno)); |
8efc0c15 | 1015 | } |
1016 | ||
1017 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
1018 | ||
5260325f | 1019 | int |
1020 | read_yes_or_no(const char *prompt, int defval) | |
8efc0c15 | 1021 | { |
5260325f | 1022 | char buf[1024]; |
1023 | FILE *f; | |
1024 | int retval = -1; | |
1025 | ||
1026 | if (isatty(0)) | |
1027 | f = stdin; | |
1028 | else | |
1029 | f = fopen("/dev/tty", "rw"); | |
1030 | ||
1031 | if (f == NULL) | |
1032 | return 0; | |
1033 | ||
1034 | fflush(stdout); | |
1035 | ||
1036 | while (1) { | |
1037 | fprintf(stderr, "%s", prompt); | |
1038 | if (fgets(buf, sizeof(buf), f) == NULL) { | |
1039 | /* Print a newline (the prompt probably didn\'t have one). */ | |
1040 | fprintf(stderr, "\n"); | |
1041 | strlcpy(buf, "no", sizeof buf); | |
1042 | } | |
1043 | /* Remove newline from response. */ | |
1044 | if (strchr(buf, '\n')) | |
1045 | *strchr(buf, '\n') = 0; | |
1046 | ||
1047 | if (buf[0] == 0) | |
1048 | retval = defval; | |
1049 | if (strcmp(buf, "yes") == 0) | |
1050 | retval = 1; | |
1051 | if (strcmp(buf, "no") == 0) | |
1052 | retval = 0; | |
1053 | ||
1054 | if (retval != -1) { | |
1055 | if (f != stdin) | |
1056 | fclose(f); | |
1057 | return retval; | |
1058 | } | |
8efc0c15 | 1059 | } |
8efc0c15 | 1060 | } |
1061 | ||
5260325f | 1062 | /* |
95f1eccc | 1063 | * check whether the supplied host key is valid, return only if ok. |
5260325f | 1064 | */ |
95f1eccc | 1065 | |
5260325f | 1066 | void |
48e671d5 | 1067 | check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key) |
8efc0c15 | 1068 | { |
95f1eccc | 1069 | RSA *file_key; |
1070 | char *ip = NULL; | |
5260325f | 1071 | char hostline[1000], *hostp; |
5260325f | 1072 | HostStatus host_status; |
1073 | HostStatus ip_status; | |
48e671d5 | 1074 | int local = 0, host_ip_differ = 0; |
20af321f | 1075 | int salen; |
48e671d5 | 1076 | char ntop[NI_MAXHOST]; |
1077 | ||
1078 | /* | |
1079 | * Force accepting of the host key for loopback/localhost. The | |
1080 | * problem is that if the home directory is NFS-mounted to multiple | |
1081 | * machines, localhost will refer to a different machine in each of | |
1082 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
1083 | * essentially disables host authentication for localhost; however, | |
1084 | * this is probably not a real problem. | |
1085 | */ | |
1086 | switch (hostaddr->sa_family) { | |
1087 | case AF_INET: | |
1088 | local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; | |
20af321f | 1089 | salen = sizeof(struct sockaddr_in); |
48e671d5 | 1090 | break; |
1091 | case AF_INET6: | |
1092 | local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
20af321f | 1093 | salen = sizeof(struct sockaddr_in6); |
48e671d5 | 1094 | break; |
1095 | default: | |
1096 | local = 0; | |
20af321f | 1097 | salen = sizeof(struct sockaddr_storage); |
48e671d5 | 1098 | break; |
1099 | } | |
1100 | if (local) { | |
1101 | debug("Forcing accepting of host key for loopback/localhost."); | |
1102 | return; | |
1103 | } | |
5260325f | 1104 | |
57112b5a | 1105 | /* |
1106 | * Turn off check_host_ip for proxy connects, since | |
1107 | * we don't have the remote ip-address | |
1108 | */ | |
1109 | if (options.proxy_command != NULL && options.check_host_ip) | |
1110 | options.check_host_ip = 0; | |
1111 | ||
48e671d5 | 1112 | if (options.check_host_ip) { |
20af321f | 1113 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), |
48e671d5 | 1114 | NULL, 0, NI_NUMERICHOST) != 0) |
1115 | fatal("check_host_key: getnameinfo failed"); | |
1116 | ip = xstrdup(ntop); | |
1117 | } | |
5260325f | 1118 | |
95f1eccc | 1119 | /* |
1120 | * Store the host key from the known host file in here so that we can | |
1121 | * compare it with the key for the IP address. | |
1122 | */ | |
5260325f | 1123 | file_key = RSA_new(); |
1124 | file_key->n = BN_new(); | |
1125 | file_key->e = BN_new(); | |
1126 | ||
aa3378df | 1127 | /* |
1128 | * Check if the host key is present in the user\'s list of known | |
1129 | * hosts or in the systemwide list. | |
1130 | */ | |
5260325f | 1131 | host_status = check_host_in_hostfile(options.user_hostfile, host, |
1132 | host_key->e, host_key->n, | |
1133 | file_key->e, file_key->n); | |
1134 | if (host_status == HOST_NEW) | |
1135 | host_status = check_host_in_hostfile(options.system_hostfile, host, | |
1136 | host_key->e, host_key->n, | |
1137 | file_key->e, file_key->n); | |
aa3378df | 1138 | /* |
1139 | * Also perform check for the ip address, skip the check if we are | |
1140 | * localhost or the hostname was an ip address to begin with | |
1141 | */ | |
5260325f | 1142 | if (options.check_host_ip && !local && strcmp(host, ip)) { |
1143 | RSA *ip_key = RSA_new(); | |
1144 | ip_key->n = BN_new(); | |
1145 | ip_key->e = BN_new(); | |
1146 | ip_status = check_host_in_hostfile(options.user_hostfile, ip, | |
1147 | host_key->e, host_key->n, | |
1148 | ip_key->e, ip_key->n); | |
1149 | ||
1150 | if (ip_status == HOST_NEW) | |
1151 | ip_status = check_host_in_hostfile(options.system_hostfile, ip, | |
1152 | host_key->e, host_key->n, | |
1153 | ip_key->e, ip_key->n); | |
1154 | if (host_status == HOST_CHANGED && | |
1155 | (ip_status != HOST_CHANGED || | |
1156 | (BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n)))) | |
1157 | host_ip_differ = 1; | |
1158 | ||
1159 | RSA_free(ip_key); | |
1160 | } else | |
1161 | ip_status = host_status; | |
1162 | ||
1163 | RSA_free(file_key); | |
1164 | ||
1165 | switch (host_status) { | |
1166 | case HOST_OK: | |
1167 | /* The host is known and the key matches. */ | |
1168 | debug("Host '%.200s' is known and matches the host key.", host); | |
1169 | if (options.check_host_ip) { | |
1170 | if (ip_status == HOST_NEW) { | |
1171 | if (!add_host_to_hostfile(options.user_hostfile, ip, | |
1172 | host_key->e, host_key->n)) | |
1173 | log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).", | |
1174 | ip, options.user_hostfile); | |
1175 | else | |
1176 | log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.", | |
1177 | ip); | |
1178 | } else if (ip_status != HOST_OK) | |
1179 | log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'", | |
1180 | host, ip); | |
1181 | } | |
1182 | break; | |
1183 | case HOST_NEW: | |
1184 | /* The host is new. */ | |
1185 | if (options.strict_host_key_checking == 1) { | |
1186 | /* User has requested strict host key checking. We will not add the host key | |
1187 | automatically. The only alternative left is to abort. */ | |
1188 | fatal("No host key is known for %.200s and you have requested strict checking.", host); | |
1189 | } else if (options.strict_host_key_checking == 2) { | |
1190 | /* The default */ | |
1191 | char prompt[1024]; | |
1192 | char *fp = fingerprint(host_key->e, host_key->n); | |
1193 | snprintf(prompt, sizeof(prompt), | |
a408af76 | 1194 | "The authenticity of host '%.200s' can't be established.\n" |
1195 | "Key fingerprint is %d %s.\n" | |
1196 | "Are you sure you want to continue connecting (yes/no)? ", | |
1197 | host, BN_num_bits(host_key->n), fp); | |
5260325f | 1198 | if (!read_yes_or_no(prompt, -1)) |
1199 | fatal("Aborted by user!\n"); | |
1200 | } | |
1201 | if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) { | |
1202 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); | |
1203 | hostp = hostline; | |
1204 | } else | |
1205 | hostp = host; | |
1206 | ||
1207 | /* If not in strict mode, add the key automatically to the local known_hosts file. */ | |
1208 | if (!add_host_to_hostfile(options.user_hostfile, hostp, | |
1209 | host_key->e, host_key->n)) | |
1210 | log("Failed to add the host to the list of known hosts (%.500s).", | |
1211 | options.user_hostfile); | |
1212 | else | |
1213 | log("Warning: Permanently added '%.200s' to the list of known hosts.", | |
1214 | hostp); | |
1215 | break; | |
1216 | case HOST_CHANGED: | |
1217 | if (options.check_host_ip && host_ip_differ) { | |
1218 | char *msg; | |
1219 | if (ip_status == HOST_NEW) | |
1220 | msg = "is unknown"; | |
1221 | else if (ip_status == HOST_OK) | |
1222 | msg = "is unchanged"; | |
1223 | else | |
1224 | msg = "has a different value"; | |
1225 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1226 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
1227 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1228 | error("The host key for %s has changed,", host); | |
1229 | error("and the key for the according IP address %s", ip); | |
1230 | error("%s. This could either mean that", msg); | |
1231 | error("DNS SPOOFING is happening or the IP address for the host"); | |
1232 | error("and its host key have changed at the same time"); | |
1233 | } | |
1234 | /* The host key has changed. */ | |
1235 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
ae2f7af7 | 1236 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
5260325f | 1237 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
1238 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1239 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1240 | error("It is also possible that the host key has just been changed."); | |
1241 | error("Please contact your system administrator."); | |
1242 | error("Add correct host key in %.100s to get rid of this message.", | |
1243 | options.user_hostfile); | |
1244 | ||
aa3378df | 1245 | /* |
1246 | * If strict host key checking is in use, the user will have | |
1247 | * to edit the key manually and we can only abort. | |
1248 | */ | |
5260325f | 1249 | if (options.strict_host_key_checking) |
1250 | fatal("Host key for %.200s has changed and you have requested strict checking.", host); | |
1251 | ||
aa3378df | 1252 | /* |
1253 | * If strict host key checking has not been requested, allow | |
1254 | * the connection but without password authentication or | |
1255 | * agent forwarding. | |
1256 | */ | |
5260325f | 1257 | if (options.password_authentication) { |
1258 | error("Password authentication is disabled to avoid trojan horses."); | |
1259 | options.password_authentication = 0; | |
1260 | } | |
1261 | if (options.forward_agent) { | |
1262 | error("Agent forwarding is disabled to avoid trojan horses."); | |
1263 | options.forward_agent = 0; | |
1264 | } | |
aa3378df | 1265 | /* |
1266 | * XXX Should permit the user to change to use the new id. | |
1267 | * This could be done by converting the host key to an | |
1268 | * identifying sentence, tell that the host identifies itself | |
1269 | * by that sentence, and ask the user if he/she whishes to | |
1270 | * accept the authentication. | |
1271 | */ | |
5260325f | 1272 | break; |
1273 | } | |
5260325f | 1274 | if (options.check_host_ip) |
1275 | xfree(ip); | |
95f1eccc | 1276 | } |
1277 | ||
1278 | /* | |
7b2ea3a1 | 1279 | * SSH1 key exchange |
95f1eccc | 1280 | */ |
1281 | void | |
7b2ea3a1 | 1282 | ssh_kex(char *host, struct sockaddr *hostaddr) |
95f1eccc | 1283 | { |
7b2ea3a1 | 1284 | int i; |
95f1eccc | 1285 | BIGNUM *key; |
1286 | RSA *host_key; | |
1287 | RSA *public_key; | |
1288 | int bits, rbits; | |
1289 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
7b2ea3a1 | 1290 | unsigned char cookie[8]; |
1291 | unsigned int supported_ciphers; | |
95f1eccc | 1292 | unsigned int server_flags, client_flags; |
1293 | int payload_len, clen, sum_len = 0; | |
1294 | u_int32_t rand = 0; | |
1295 | ||
95f1eccc | 1296 | debug("Waiting for server public key."); |
1297 | ||
1298 | /* Wait for a public key packet from the server. */ | |
1299 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
1300 | ||
7b2ea3a1 | 1301 | /* Get cookie from the packet. */ |
95f1eccc | 1302 | for (i = 0; i < 8; i++) |
7b2ea3a1 | 1303 | cookie[i] = packet_get_char(); |
95f1eccc | 1304 | |
1305 | /* Get the public key. */ | |
1306 | public_key = RSA_new(); | |
1307 | bits = packet_get_int();/* bits */ | |
1308 | public_key->e = BN_new(); | |
1309 | packet_get_bignum(public_key->e, &clen); | |
1310 | sum_len += clen; | |
1311 | public_key->n = BN_new(); | |
1312 | packet_get_bignum(public_key->n, &clen); | |
1313 | sum_len += clen; | |
1314 | ||
1315 | rbits = BN_num_bits(public_key->n); | |
1316 | if (bits != rbits) { | |
1317 | log("Warning: Server lies about size of server public key: " | |
1318 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1319 | log("Warning: This may be due to an old implementation of ssh."); | |
1320 | } | |
1321 | /* Get the host key. */ | |
1322 | host_key = RSA_new(); | |
1323 | bits = packet_get_int();/* bits */ | |
1324 | host_key->e = BN_new(); | |
1325 | packet_get_bignum(host_key->e, &clen); | |
1326 | sum_len += clen; | |
1327 | host_key->n = BN_new(); | |
1328 | packet_get_bignum(host_key->n, &clen); | |
1329 | sum_len += clen; | |
1330 | ||
1331 | rbits = BN_num_bits(host_key->n); | |
1332 | if (bits != rbits) { | |
1333 | log("Warning: Server lies about size of server host key: " | |
1334 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1335 | log("Warning: This may be due to an old implementation of ssh."); | |
1336 | } | |
1337 | ||
1338 | /* Get protocol flags. */ | |
1339 | server_flags = packet_get_int(); | |
1340 | packet_set_protocol_flags(server_flags); | |
1341 | ||
1342 | supported_ciphers = packet_get_int(); | |
1343 | supported_authentications = packet_get_int(); | |
1344 | ||
1345 | debug("Received server public key (%d bits) and host key (%d bits).", | |
1346 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
1347 | ||
1348 | packet_integrity_check(payload_len, | |
1349 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
1350 | SSH_SMSG_PUBLIC_KEY); | |
1351 | ||
1352 | check_host_key(host, hostaddr, host_key); | |
1353 | ||
1354 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; | |
1355 | ||
7b2ea3a1 | 1356 | compute_session_id(session_id, cookie, host_key->n, public_key->n); |
5260325f | 1357 | |
1358 | /* Generate a session key. */ | |
1359 | arc4random_stir(); | |
1360 | ||
aa3378df | 1361 | /* |
1362 | * Generate an encryption key for the session. The key is a 256 bit | |
1363 | * random number, interpreted as a 32-byte key, with the least | |
1364 | * significant 8 bits being the first byte of the key. | |
1365 | */ | |
5260325f | 1366 | for (i = 0; i < 32; i++) { |
1367 | if (i % 4 == 0) | |
1368 | rand = arc4random(); | |
1369 | session_key[i] = rand & 0xff; | |
1370 | rand >>= 8; | |
1371 | } | |
1372 | ||
aa3378df | 1373 | /* |
1374 | * According to the protocol spec, the first byte of the session key | |
1375 | * is the highest byte of the integer. The session key is xored with | |
1376 | * the first 16 bytes of the session id. | |
1377 | */ | |
5260325f | 1378 | key = BN_new(); |
1379 | BN_set_word(key, 0); | |
1380 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1381 | BN_lshift(key, key, 8); | |
1382 | if (i < 16) | |
1383 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1384 | else | |
1385 | BN_add_word(key, session_key[i]); | |
1386 | } | |
1387 | ||
aa3378df | 1388 | /* |
1389 | * Encrypt the integer using the public key and host key of the | |
1390 | * server (key with smaller modulus first). | |
1391 | */ | |
5260325f | 1392 | if (BN_cmp(public_key->n, host_key->n) < 0) { |
1393 | /* Public key has smaller modulus. */ | |
1394 | if (BN_num_bits(host_key->n) < | |
1395 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1396 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1397 | "SSH_KEY_BITS_RESERVED %d", | |
1398 | BN_num_bits(host_key->n), | |
1399 | BN_num_bits(public_key->n), | |
1400 | SSH_KEY_BITS_RESERVED); | |
1401 | } | |
1402 | rsa_public_encrypt(key, key, public_key); | |
1403 | rsa_public_encrypt(key, key, host_key); | |
1404 | } else { | |
1405 | /* Host key has smaller modulus (or they are equal). */ | |
1406 | if (BN_num_bits(public_key->n) < | |
1407 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1408 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1409 | "SSH_KEY_BITS_RESERVED %d", | |
1410 | BN_num_bits(public_key->n), | |
1411 | BN_num_bits(host_key->n), | |
1412 | SSH_KEY_BITS_RESERVED); | |
1413 | } | |
1414 | rsa_public_encrypt(key, key, host_key); | |
1415 | rsa_public_encrypt(key, key, public_key); | |
1416 | } | |
1417 | ||
7b2ea3a1 | 1418 | /* Destroy the public keys since we no longer need them. */ |
1419 | RSA_free(public_key); | |
1420 | RSA_free(host_key); | |
1421 | ||
5260325f | 1422 | if (options.cipher == SSH_CIPHER_NOT_SET) { |
1423 | if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default)) | |
1424 | options.cipher = ssh_cipher_default; | |
1425 | else { | |
1426 | debug("Cipher %s not supported, using %.100s instead.", | |
1427 | cipher_name(ssh_cipher_default), | |
1428 | cipher_name(SSH_FALLBACK_CIPHER)); | |
1429 | options.cipher = SSH_FALLBACK_CIPHER; | |
1430 | } | |
1431 | } | |
1432 | /* Check that the selected cipher is supported. */ | |
1433 | if (!(supported_ciphers & (1 << options.cipher))) | |
1434 | fatal("Selected cipher type %.100s not supported by server.", | |
1435 | cipher_name(options.cipher)); | |
1436 | ||
1437 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1438 | ||
1439 | /* Send the encrypted session key to the server. */ | |
1440 | packet_start(SSH_CMSG_SESSION_KEY); | |
1441 | packet_put_char(options.cipher); | |
1442 | ||
7b2ea3a1 | 1443 | /* Send the cookie back to the server. */ |
5260325f | 1444 | for (i = 0; i < 8; i++) |
7b2ea3a1 | 1445 | packet_put_char(cookie[i]); |
5260325f | 1446 | |
7b2ea3a1 | 1447 | /* Send and destroy the encrypted encryption key integer. */ |
5260325f | 1448 | packet_put_bignum(key); |
7b2ea3a1 | 1449 | BN_clear_free(key); |
5260325f | 1450 | |
1451 | /* Send protocol flags. */ | |
95f1eccc | 1452 | packet_put_int(client_flags); |
5260325f | 1453 | |
1454 | /* Send the packet now. */ | |
8efc0c15 | 1455 | packet_send(); |
1456 | packet_write_wait(); | |
5260325f | 1457 | |
5260325f | 1458 | debug("Sent encrypted session key."); |
1459 | ||
1460 | /* Set the encryption key. */ | |
1461 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1462 | ||
1463 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1464 | memset(session_key, 0, sizeof(session_key)); | |
1465 | ||
aa3378df | 1466 | /* |
1467 | * Expect a success message from the server. Note that this message | |
1468 | * will be received in encrypted form. | |
1469 | */ | |
5260325f | 1470 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); |
1471 | ||
1472 | debug("Received encrypted confirmation."); | |
7b2ea3a1 | 1473 | } |
1474 | ||
1475 | /* | |
1476 | * Authenticate user | |
1477 | */ | |
1478 | void | |
1479 | ssh_userauth(int host_key_valid, RSA *own_host_key, | |
1480 | uid_t original_real_uid, char *host) | |
1481 | { | |
1482 | int i, type; | |
1483 | int payload_len; | |
1484 | struct passwd *pw; | |
1485 | const char *server_user, *local_user; | |
1486 | ||
1487 | /* Get local user name. Use it as server user if no user name was given. */ | |
1488 | pw = getpwuid(original_real_uid); | |
1489 | if (!pw) | |
1490 | fatal("User id %d not found from user database.", original_real_uid); | |
1491 | local_user = xstrdup(pw->pw_name); | |
1492 | server_user = options.user ? options.user : local_user; | |
5260325f | 1493 | |
1494 | /* Send the name of the user to log in as on the server. */ | |
1495 | packet_start(SSH_CMSG_USER); | |
1496 | packet_put_string(server_user, strlen(server_user)); | |
1497 | packet_send(); | |
1498 | packet_write_wait(); | |
1499 | ||
aa3378df | 1500 | /* |
1501 | * The server should respond with success if no authentication is | |
1502 | * needed (the user has no password). Otherwise the server responds | |
1503 | * with failure. | |
1504 | */ | |
8efc0c15 | 1505 | type = packet_read(&payload_len); |
5260325f | 1506 | |
1507 | /* check whether the connection was accepted without authentication. */ | |
8efc0c15 | 1508 | if (type == SSH_SMSG_SUCCESS) |
5260325f | 1509 | return; |
8efc0c15 | 1510 | if (type != SSH_SMSG_FAILURE) |
5260325f | 1511 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", |
1512 | type); | |
1513 | ||
1514 | #ifdef AFS | |
1515 | /* Try Kerberos tgt passing if the server supports it. */ | |
1516 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1517 | options.kerberos_tgt_passing) { | |
1518 | if (options.cipher == SSH_CIPHER_NONE) | |
1519 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1520 | (void) send_kerberos_tgt(); | |
1521 | } | |
1522 | /* Try AFS token passing if the server supports it. */ | |
1523 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1524 | options.afs_token_passing && k_hasafs()) { | |
1525 | if (options.cipher == SSH_CIPHER_NONE) | |
1526 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1527 | send_afs_tokens(); | |
1528 | } | |
1529 | #endif /* AFS */ | |
8efc0c15 | 1530 | |
5260325f | 1531 | #ifdef KRB4 |
1532 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1533 | options.kerberos_authentication) { | |
1534 | debug("Trying Kerberos authentication."); | |
1535 | if (try_kerberos_authentication()) { | |
1536 | /* The server should respond with success or failure. */ | |
1537 | type = packet_read(&payload_len); | |
1538 | if (type == SSH_SMSG_SUCCESS) | |
1539 | return; | |
1540 | if (type != SSH_SMSG_FAILURE) | |
1541 | packet_disconnect("Protocol error: got %d in response to Kerberos auth", type); | |
1542 | } | |
1543 | } | |
1544 | #endif /* KRB4 */ | |
1545 | ||
aa3378df | 1546 | /* |
1547 | * Use rhosts authentication if running in privileged socket and we | |
1548 | * do not wish to remain anonymous. | |
1549 | */ | |
5260325f | 1550 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && |
1551 | options.rhosts_authentication) { | |
1552 | debug("Trying rhosts authentication."); | |
1553 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
1554 | packet_put_string(local_user, strlen(local_user)); | |
1555 | packet_send(); | |
1556 | packet_write_wait(); | |
1557 | ||
1558 | /* The server should respond with success or failure. */ | |
1559 | type = packet_read(&payload_len); | |
1560 | if (type == SSH_SMSG_SUCCESS) | |
1561 | return; | |
1562 | if (type != SSH_SMSG_FAILURE) | |
1563 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1564 | type); | |
1565 | } | |
aa3378df | 1566 | /* |
1567 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1568 | * authentication. | |
1569 | */ | |
5260325f | 1570 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && |
1571 | options.rhosts_rsa_authentication && host_key_valid) { | |
1572 | if (try_rhosts_rsa_authentication(local_user, own_host_key)) | |
1573 | return; | |
1574 | } | |
1575 | /* Try RSA authentication if the server supports it. */ | |
1576 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1577 | options.rsa_authentication) { | |
aa3378df | 1578 | /* |
1579 | * Try RSA authentication using the authentication agent. The | |
1580 | * agent is tried first because no passphrase is needed for | |
1581 | * it, whereas identity files may require passphrases. | |
1582 | */ | |
5260325f | 1583 | if (try_agent_authentication()) |
1584 | return; | |
1585 | ||
1586 | /* Try RSA authentication for each identity. */ | |
1587 | for (i = 0; i < options.num_identity_files; i++) | |
57112b5a | 1588 | if (try_rsa_authentication(options.identity_files[i])) |
5260325f | 1589 | return; |
1590 | } | |
1591 | /* Try skey authentication if the server supports it. */ | |
1592 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && | |
1593 | options.skey_authentication && !options.batch_mode) { | |
57112b5a | 1594 | if (try_skey_authentication()) |
1595 | return; | |
5260325f | 1596 | } |
1597 | /* Try password authentication if the server supports it. */ | |
1598 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1599 | options.password_authentication && !options.batch_mode) { | |
1600 | char prompt[80]; | |
a408af76 | 1601 | |
57112b5a | 1602 | snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
a408af76 | 1603 | server_user, host); |
57112b5a | 1604 | if (try_password_authentication(prompt)) |
1605 | return; | |
5260325f | 1606 | } |
1607 | /* All authentication methods have failed. Exit with an error message. */ | |
1608 | fatal("Permission denied."); | |
1609 | /* NOTREACHED */ | |
8efc0c15 | 1610 | } |
7b2ea3a1 | 1611 | |
1612 | /* | |
1613 | * Starts a dialog with the server, and authenticates the current user on the | |
1614 | * server. This does not need any extra privileges. The basic connection | |
1615 | * to the server must already have been established before this is called. | |
1616 | * If login fails, this function prints an error and never returns. | |
1617 | * This function does not require super-user privileges. | |
1618 | */ | |
1619 | void | |
1620 | ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost, | |
1621 | struct sockaddr *hostaddr, uid_t original_real_uid) | |
1622 | { | |
1623 | char *host, *cp; | |
1624 | ||
1625 | /* Convert the user-supplied hostname into all lowercase. */ | |
1626 | host = xstrdup(orighost); | |
1627 | for (cp = host; *cp; cp++) | |
1628 | if (isupper(*cp)) | |
1629 | *cp = tolower(*cp); | |
1630 | ||
1631 | /* Exchange protocol version identification strings with the server. */ | |
1632 | ssh_exchange_identification(); | |
1633 | ||
1634 | /* Put the connection into non-blocking mode. */ | |
1635 | packet_set_nonblocking(); | |
1636 | ||
1637 | supported_authentications = 0; | |
1638 | /* key exchange */ | |
1639 | ssh_kex(host, hostaddr); | |
1640 | if (supported_authentications == 0) | |
1641 | fatal("supported_authentications == 0."); | |
1642 | /* authenticate user */ | |
1643 | ssh_userauth(host_key_valid, own_host_key, original_real_uid, host); | |
1644 | } |