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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" | |
c8d54615 | 11 | RCSID("$OpenBSD: sshconnect.c,v 1.56 2000/02/18 08:50:33 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) |
c8d54615 | 159 | error("rresvport: af=%d %.100s", family, strerror(errno)); |
160 | else | |
161 | debug("Allocated local port %d.", p); | |
5260325f | 162 | } else { |
95f1eccc | 163 | /* |
164 | * Just create an ordinary socket on arbitrary port. We use | |
165 | * the user's uid to create the socket. | |
166 | */ | |
5260325f | 167 | temporarily_use_uid(original_real_uid); |
48e671d5 | 168 | sock = socket(family, SOCK_STREAM, 0); |
5260325f | 169 | if (sock < 0) |
48e671d5 | 170 | error("socket: %.100s", strerror(errno)); |
5260325f | 171 | restore_uid(); |
172 | } | |
173 | return sock; | |
8efc0c15 | 174 | } |
175 | ||
5260325f | 176 | /* |
48e671d5 | 177 | * Opens a TCP/IP connection to the remote server on the given host. |
178 | * The address of the remote host will be returned in hostaddr. | |
179 | * If port is 0, the default port will be used. If anonymous is zero, | |
5260325f | 180 | * a privileged port will be allocated to make the connection. |
181 | * This requires super-user privileges if anonymous is false. | |
182 | * Connection_attempts specifies the maximum number of tries (one per | |
183 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
184 | * and %p substituted for host and port, respectively) to use to contact | |
185 | * the daemon. | |
186 | */ | |
187 | int | |
48e671d5 | 188 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
57112b5a | 189 | u_short port, int connection_attempts, |
5260325f | 190 | int anonymous, uid_t original_real_uid, |
191 | const char *proxy_command) | |
8efc0c15 | 192 | { |
48e671d5 | 193 | int sock = -1, attempt; |
5260325f | 194 | struct servent *sp; |
48e671d5 | 195 | struct addrinfo hints, *ai, *aitop; |
196 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
197 | int gaierr; | |
5260325f | 198 | struct linger linger; |
199 | ||
200 | debug("ssh_connect: getuid %d geteuid %d anon %d", | |
201 | (int) getuid(), (int) geteuid(), anonymous); | |
202 | ||
203 | /* Get default port if port has not been set. */ | |
204 | if (port == 0) { | |
205 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); | |
206 | if (sp) | |
207 | port = ntohs(sp->s_port); | |
208 | else | |
209 | port = SSH_DEFAULT_PORT; | |
8efc0c15 | 210 | } |
5260325f | 211 | /* If a proxy command is given, connect using it. */ |
212 | if (proxy_command != NULL) | |
213 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); | |
214 | ||
215 | /* No proxy command. */ | |
216 | ||
48e671d5 | 217 | memset(&hints, 0, sizeof(hints)); |
218 | hints.ai_family = IPv4or6; | |
219 | hints.ai_socktype = SOCK_STREAM; | |
220 | snprintf(strport, sizeof strport, "%d", port); | |
221 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) | |
222 | fatal("%s: %.100s: %s", __progname, host, | |
223 | gai_strerror(gaierr)); | |
5260325f | 224 | |
95f1eccc | 225 | /* |
226 | * Try to connect several times. On some machines, the first time | |
227 | * will sometimes fail. In general socket code appears to behave | |
228 | * quite magically on many machines. | |
229 | */ | |
5260325f | 230 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
231 | if (attempt > 0) | |
232 | debug("Trying again..."); | |
233 | ||
48e671d5 | 234 | /* Loop through addresses for this host, and try each one in |
235 | sequence until the connection succeeds. */ | |
236 | for (ai = aitop; ai; ai = ai->ai_next) { | |
237 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
238 | continue; | |
239 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
240 | ntop, sizeof(ntop), strport, sizeof(strport), | |
241 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
242 | error("ssh_connect: getnameinfo failed"); | |
243 | continue; | |
244 | } | |
245 | debug("Connecting to %.200s [%.100s] port %s.", | |
246 | host, ntop, strport); | |
247 | ||
248 | /* Create a socket for connecting. */ | |
249 | sock = ssh_create_socket(original_real_uid, | |
250 | !anonymous && geteuid() == 0 && port < IPPORT_RESERVED, | |
251 | ai->ai_family); | |
252 | if (sock < 0) | |
253 | continue; | |
254 | ||
255 | /* Connect to the host. We use the user's uid in the | |
256 | * hope that it will help with tcp_wrappers showing | |
257 | * the remote uid as root. | |
aa3378df | 258 | */ |
5260325f | 259 | temporarily_use_uid(original_real_uid); |
48e671d5 | 260 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { |
261 | /* Successful connection. */ | |
262 | memcpy(hostaddr, ai->ai_addr, sizeof(*(ai->ai_addr))); | |
5260325f | 263 | restore_uid(); |
264 | break; | |
48e671d5 | 265 | } else { |
5260325f | 266 | debug("connect: %.100s", strerror(errno)); |
267 | restore_uid(); | |
aa3378df | 268 | /* |
269 | * Close the failed socket; there appear to | |
270 | * be some problems when reusing a socket for | |
271 | * which connect() has already returned an | |
272 | * error. | |
273 | */ | |
5260325f | 274 | shutdown(sock, SHUT_RDWR); |
275 | close(sock); | |
276 | } | |
8efc0c15 | 277 | } |
48e671d5 | 278 | if (ai) |
279 | break; /* Successful connection. */ | |
8efc0c15 | 280 | |
5260325f | 281 | /* Sleep a moment before retrying. */ |
282 | sleep(1); | |
283 | } | |
48e671d5 | 284 | |
285 | freeaddrinfo(aitop); | |
286 | ||
5260325f | 287 | /* Return failure if we didn't get a successful connection. */ |
288 | if (attempt >= connection_attempts) | |
289 | return 0; | |
8efc0c15 | 290 | |
5260325f | 291 | debug("Connection established."); |
8efc0c15 | 292 | |
aa3378df | 293 | /* |
294 | * Set socket options. We would like the socket to disappear as soon | |
295 | * as it has been closed for whatever reason. | |
296 | */ | |
297 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 298 | linger.l_onoff = 1; |
299 | linger.l_linger = 5; | |
300 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
8efc0c15 | 301 | |
5260325f | 302 | /* Set the connection. */ |
303 | packet_set_connection(sock, sock); | |
8efc0c15 | 304 | |
5260325f | 305 | return 1; |
8efc0c15 | 306 | } |
307 | ||
5260325f | 308 | /* |
309 | * Checks if the user has an authentication agent, and if so, tries to | |
310 | * authenticate using the agent. | |
311 | */ | |
8efc0c15 | 312 | int |
313 | try_agent_authentication() | |
314 | { | |
5260325f | 315 | int status, type; |
316 | char *comment; | |
317 | AuthenticationConnection *auth; | |
318 | unsigned char response[16]; | |
319 | unsigned int i; | |
320 | BIGNUM *e, *n, *challenge; | |
321 | ||
322 | /* Get connection to the agent. */ | |
323 | auth = ssh_get_authentication_connection(); | |
324 | if (!auth) | |
325 | return 0; | |
326 | ||
327 | e = BN_new(); | |
328 | n = BN_new(); | |
329 | challenge = BN_new(); | |
330 | ||
331 | /* Loop through identities served by the agent. */ | |
332 | for (status = ssh_get_first_identity(auth, e, n, &comment); | |
333 | status; | |
334 | status = ssh_get_next_identity(auth, e, n, &comment)) { | |
335 | int plen, clen; | |
336 | ||
337 | /* Try this identity. */ | |
338 | debug("Trying RSA authentication via agent with '%.100s'", comment); | |
339 | xfree(comment); | |
340 | ||
341 | /* Tell the server that we are willing to authenticate using this key. */ | |
342 | packet_start(SSH_CMSG_AUTH_RSA); | |
343 | packet_put_bignum(n); | |
344 | packet_send(); | |
345 | packet_write_wait(); | |
346 | ||
347 | /* Wait for server's response. */ | |
348 | type = packet_read(&plen); | |
349 | ||
350 | /* The server sends failure if it doesn\'t like our key or | |
351 | does not support RSA authentication. */ | |
352 | if (type == SSH_SMSG_FAILURE) { | |
353 | debug("Server refused our key."); | |
354 | continue; | |
355 | } | |
356 | /* Otherwise it should have sent a challenge. */ | |
357 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
358 | packet_disconnect("Protocol error during RSA authentication: %d", | |
359 | type); | |
8efc0c15 | 360 | |
5260325f | 361 | packet_get_bignum(challenge, &clen); |
8efc0c15 | 362 | |
5260325f | 363 | packet_integrity_check(plen, clen, type); |
8efc0c15 | 364 | |
5260325f | 365 | debug("Received RSA challenge from server."); |
366 | ||
367 | /* Ask the agent to decrypt the challenge. */ | |
368 | if (!ssh_decrypt_challenge(auth, e, n, challenge, | |
369 | session_id, 1, response)) { | |
370 | /* The agent failed to authenticate this identifier although it | |
371 | advertised it supports this. Just return a wrong value. */ | |
372 | log("Authentication agent failed to decrypt challenge."); | |
373 | memset(response, 0, sizeof(response)); | |
374 | } | |
375 | debug("Sending response to RSA challenge."); | |
376 | ||
377 | /* Send the decrypted challenge back to the server. */ | |
378 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
379 | for (i = 0; i < 16; i++) | |
380 | packet_put_char(response[i]); | |
381 | packet_send(); | |
382 | packet_write_wait(); | |
383 | ||
384 | /* Wait for response from the server. */ | |
385 | type = packet_read(&plen); | |
386 | ||
387 | /* The server returns success if it accepted the authentication. */ | |
388 | if (type == SSH_SMSG_SUCCESS) { | |
389 | debug("RSA authentication accepted by server."); | |
390 | BN_clear_free(e); | |
391 | BN_clear_free(n); | |
392 | BN_clear_free(challenge); | |
393 | return 1; | |
394 | } | |
395 | /* Otherwise it should return failure. */ | |
396 | if (type != SSH_SMSG_FAILURE) | |
397 | packet_disconnect("Protocol error waiting RSA auth response: %d", | |
398 | type); | |
399 | } | |
400 | ||
401 | BN_clear_free(e); | |
402 | BN_clear_free(n); | |
403 | BN_clear_free(challenge); | |
8efc0c15 | 404 | |
5260325f | 405 | debug("RSA authentication using agent refused."); |
406 | return 0; | |
407 | } | |
8efc0c15 | 408 | |
5260325f | 409 | /* |
410 | * Computes the proper response to a RSA challenge, and sends the response to | |
411 | * the server. | |
412 | */ | |
8efc0c15 | 413 | void |
5260325f | 414 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
8efc0c15 | 415 | { |
5260325f | 416 | unsigned char buf[32], response[16]; |
417 | MD5_CTX md; | |
418 | int i, len; | |
419 | ||
420 | /* Decrypt the challenge using the private key. */ | |
421 | rsa_private_decrypt(challenge, challenge, prv); | |
422 | ||
423 | /* Compute the response. */ | |
424 | /* The response is MD5 of decrypted challenge plus session id. */ | |
425 | len = BN_num_bytes(challenge); | |
426 | if (len <= 0 || len > sizeof(buf)) | |
427 | packet_disconnect("respond_to_rsa_challenge: bad challenge length %d", | |
428 | len); | |
429 | ||
430 | memset(buf, 0, sizeof(buf)); | |
431 | BN_bn2bin(challenge, buf + sizeof(buf) - len); | |
432 | MD5_Init(&md); | |
433 | MD5_Update(&md, buf, 32); | |
434 | MD5_Update(&md, session_id, 16); | |
435 | MD5_Final(response, &md); | |
436 | ||
437 | debug("Sending response to host key RSA challenge."); | |
438 | ||
439 | /* Send the response back to the server. */ | |
440 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
441 | for (i = 0; i < 16; i++) | |
442 | packet_put_char(response[i]); | |
443 | packet_send(); | |
444 | packet_write_wait(); | |
8efc0c15 | 445 | |
5260325f | 446 | memset(buf, 0, sizeof(buf)); |
447 | memset(response, 0, sizeof(response)); | |
448 | memset(&md, 0, sizeof(md)); | |
449 | } | |
8efc0c15 | 450 | |
5260325f | 451 | /* |
452 | * Checks if the user has authentication file, and if so, tries to authenticate | |
453 | * the user using it. | |
454 | */ | |
8efc0c15 | 455 | int |
57112b5a | 456 | try_rsa_authentication(const char *authfile) |
8efc0c15 | 457 | { |
5260325f | 458 | BIGNUM *challenge; |
459 | RSA *private_key; | |
460 | RSA *public_key; | |
461 | char *passphrase, *comment; | |
462 | int type, i; | |
463 | int plen, clen; | |
464 | ||
465 | /* Try to load identification for the authentication key. */ | |
466 | public_key = RSA_new(); | |
467 | if (!load_public_key(authfile, public_key, &comment)) { | |
468 | RSA_free(public_key); | |
57112b5a | 469 | /* Could not load it. Fail. */ |
470 | return 0; | |
8efc0c15 | 471 | } |
5260325f | 472 | debug("Trying RSA authentication with key '%.100s'", comment); |
473 | ||
474 | /* Tell the server that we are willing to authenticate using this key. */ | |
475 | packet_start(SSH_CMSG_AUTH_RSA); | |
476 | packet_put_bignum(public_key->n); | |
477 | packet_send(); | |
478 | packet_write_wait(); | |
479 | ||
480 | /* We no longer need the public key. */ | |
481 | RSA_free(public_key); | |
482 | ||
483 | /* Wait for server's response. */ | |
484 | type = packet_read(&plen); | |
485 | ||
aa3378df | 486 | /* |
487 | * The server responds with failure if it doesn\'t like our key or | |
488 | * doesn\'t support RSA authentication. | |
489 | */ | |
5260325f | 490 | if (type == SSH_SMSG_FAILURE) { |
491 | debug("Server refused our key."); | |
492 | xfree(comment); | |
57112b5a | 493 | return 0; |
8efc0c15 | 494 | } |
5260325f | 495 | /* Otherwise, the server should respond with a challenge. */ |
496 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
497 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
498 | ||
499 | /* Get the challenge from the packet. */ | |
500 | challenge = BN_new(); | |
501 | packet_get_bignum(challenge, &clen); | |
502 | ||
503 | packet_integrity_check(plen, clen, type); | |
504 | ||
505 | debug("Received RSA challenge from server."); | |
506 | ||
507 | private_key = RSA_new(); | |
aa3378df | 508 | /* |
509 | * Load the private key. Try first with empty passphrase; if it | |
510 | * fails, ask for a passphrase. | |
511 | */ | |
5260325f | 512 | if (!load_private_key(authfile, "", private_key, NULL)) { |
513 | char buf[300]; | |
514 | snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ", | |
a408af76 | 515 | comment); |
5260325f | 516 | if (!options.batch_mode) |
517 | passphrase = read_passphrase(buf, 0); | |
518 | else { | |
519 | debug("Will not query passphrase for %.100s in batch mode.", | |
520 | comment); | |
521 | passphrase = xstrdup(""); | |
522 | } | |
8efc0c15 | 523 | |
5260325f | 524 | /* Load the authentication file using the pasphrase. */ |
525 | if (!load_private_key(authfile, passphrase, private_key, NULL)) { | |
526 | memset(passphrase, 0, strlen(passphrase)); | |
527 | xfree(passphrase); | |
528 | error("Bad passphrase."); | |
529 | ||
530 | /* Send a dummy response packet to avoid protocol error. */ | |
531 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
532 | for (i = 0; i < 16; i++) | |
533 | packet_put_char(0); | |
534 | packet_send(); | |
535 | packet_write_wait(); | |
536 | ||
537 | /* Expect the server to reject it... */ | |
538 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
539 | xfree(comment); | |
540 | return 0; | |
541 | } | |
542 | /* Destroy the passphrase. */ | |
543 | memset(passphrase, 0, strlen(passphrase)); | |
544 | xfree(passphrase); | |
545 | } | |
546 | /* We no longer need the comment. */ | |
547 | xfree(comment); | |
548 | ||
549 | /* Compute and send a response to the challenge. */ | |
550 | respond_to_rsa_challenge(challenge, private_key); | |
551 | ||
552 | /* Destroy the private key. */ | |
553 | RSA_free(private_key); | |
8efc0c15 | 554 | |
5260325f | 555 | /* We no longer need the challenge. */ |
556 | BN_clear_free(challenge); | |
557 | ||
558 | /* Wait for response from the server. */ | |
559 | type = packet_read(&plen); | |
560 | if (type == SSH_SMSG_SUCCESS) { | |
561 | debug("RSA authentication accepted by server."); | |
562 | return 1; | |
563 | } | |
564 | if (type != SSH_SMSG_FAILURE) | |
565 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
566 | debug("RSA authentication refused."); | |
567 | return 0; | |
568 | } | |
8efc0c15 | 569 | |
5260325f | 570 | /* |
571 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
572 | * authentication and RSA host authentication. | |
573 | */ | |
8efc0c15 | 574 | int |
5260325f | 575 | try_rhosts_rsa_authentication(const char *local_user, RSA * host_key) |
8efc0c15 | 576 | { |
5260325f | 577 | int type; |
578 | BIGNUM *challenge; | |
579 | int plen, clen; | |
580 | ||
581 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
582 | ||
583 | /* Tell the server that we are willing to authenticate using this key. */ | |
584 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
585 | packet_put_string(local_user, strlen(local_user)); | |
586 | packet_put_int(BN_num_bits(host_key->n)); | |
587 | packet_put_bignum(host_key->e); | |
588 | packet_put_bignum(host_key->n); | |
589 | packet_send(); | |
590 | packet_write_wait(); | |
591 | ||
592 | /* Wait for server's response. */ | |
593 | type = packet_read(&plen); | |
594 | ||
595 | /* The server responds with failure if it doesn't admit our | |
596 | .rhosts authentication or doesn't know our host key. */ | |
597 | if (type == SSH_SMSG_FAILURE) { | |
598 | debug("Server refused our rhosts authentication or host key."); | |
599 | return 0; | |
600 | } | |
601 | /* Otherwise, the server should respond with a challenge. */ | |
602 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
603 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
604 | ||
605 | /* Get the challenge from the packet. */ | |
606 | challenge = BN_new(); | |
607 | packet_get_bignum(challenge, &clen); | |
608 | ||
609 | packet_integrity_check(plen, clen, type); | |
610 | ||
611 | debug("Received RSA challenge for host key from server."); | |
612 | ||
613 | /* Compute a response to the challenge. */ | |
614 | respond_to_rsa_challenge(challenge, host_key); | |
615 | ||
616 | /* We no longer need the challenge. */ | |
617 | BN_clear_free(challenge); | |
618 | ||
619 | /* Wait for response from the server. */ | |
620 | type = packet_read(&plen); | |
621 | if (type == SSH_SMSG_SUCCESS) { | |
622 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
623 | return 1; | |
624 | } | |
625 | if (type != SSH_SMSG_FAILURE) | |
626 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
627 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
628 | return 0; | |
8efc0c15 | 629 | } |
630 | ||
631 | #ifdef KRB4 | |
5260325f | 632 | int |
633 | try_kerberos_authentication() | |
8efc0c15 | 634 | { |
5260325f | 635 | KTEXT_ST auth; /* Kerberos data */ |
636 | char *reply; | |
637 | char inst[INST_SZ]; | |
638 | char *realm; | |
639 | CREDENTIALS cred; | |
640 | int r, type, plen; | |
641 | Key_schedule schedule; | |
642 | u_long checksum, cksum; | |
643 | MSG_DAT msg_data; | |
644 | struct sockaddr_in local, foreign; | |
645 | struct stat st; | |
646 | ||
647 | /* Don't do anything if we don't have any tickets. */ | |
648 | if (stat(tkt_string(), &st) < 0) | |
649 | return 0; | |
650 | ||
651 | strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ); | |
652 | ||
653 | realm = (char *) krb_realmofhost(get_canonical_hostname()); | |
654 | if (!realm) { | |
655 | debug("Kerberos V4: no realm for %s", get_canonical_hostname()); | |
656 | return 0; | |
657 | } | |
658 | /* This can really be anything. */ | |
659 | checksum = (u_long) getpid(); | |
660 | ||
661 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); | |
662 | if (r != KSUCCESS) { | |
663 | debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]); | |
664 | return 0; | |
665 | } | |
666 | /* Get session key to decrypt the server's reply with. */ | |
667 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
668 | if (r != KSUCCESS) { | |
669 | debug("get_cred failed: %s", krb_err_txt[r]); | |
670 | return 0; | |
671 | } | |
672 | des_key_sched((des_cblock *) cred.session, schedule); | |
673 | ||
674 | /* Send authentication info to server. */ | |
675 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
676 | packet_put_string((char *) auth.dat, auth.length); | |
677 | packet_send(); | |
678 | packet_write_wait(); | |
679 | ||
680 | /* Zero the buffer. */ | |
681 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
682 | ||
683 | r = sizeof(local); | |
684 | memset(&local, 0, sizeof(local)); | |
685 | if (getsockname(packet_get_connection_in(), | |
686 | (struct sockaddr *) & local, &r) < 0) | |
687 | debug("getsockname failed: %s", strerror(errno)); | |
688 | ||
689 | r = sizeof(foreign); | |
690 | memset(&foreign, 0, sizeof(foreign)); | |
691 | if (getpeername(packet_get_connection_in(), | |
692 | (struct sockaddr *) & foreign, &r) < 0) { | |
693 | debug("getpeername failed: %s", strerror(errno)); | |
694 | fatal_cleanup(); | |
695 | } | |
696 | /* Get server reply. */ | |
697 | type = packet_read(&plen); | |
698 | switch (type) { | |
699 | case SSH_SMSG_FAILURE: | |
700 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
701 | debug("Kerberos V4 authentication failed."); | |
702 | return 0; | |
703 | break; | |
704 | ||
705 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
706 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
707 | debug("Kerberos V4 authentication accepted."); | |
708 | ||
709 | /* Get server's response. */ | |
710 | reply = packet_get_string((unsigned int *) &auth.length); | |
711 | memcpy(auth.dat, reply, auth.length); | |
712 | xfree(reply); | |
713 | ||
714 | packet_integrity_check(plen, 4 + auth.length, type); | |
715 | ||
aa3378df | 716 | /* |
717 | * If his response isn't properly encrypted with the session | |
718 | * key, and the decrypted checksum fails to match, he's | |
719 | * bogus. Bail out. | |
720 | */ | |
5260325f | 721 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, |
722 | &foreign, &local, &msg_data); | |
723 | if (r != KSUCCESS) { | |
724 | debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]); | |
725 | packet_disconnect("Kerberos V4 challenge failed!"); | |
726 | } | |
727 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
728 | (void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum)); | |
729 | cksum = ntohl(cksum); | |
730 | ||
731 | /* If it matches, we're golden. */ | |
732 | if (cksum == checksum + 1) { | |
733 | debug("Kerberos V4 challenge successful."); | |
734 | return 1; | |
735 | } else | |
736 | packet_disconnect("Kerberos V4 challenge failed!"); | |
737 | break; | |
738 | ||
739 | default: | |
740 | packet_disconnect("Protocol error on Kerberos V4 response: %d", type); | |
741 | } | |
742 | return 0; | |
8efc0c15 | 743 | } |
5260325f | 744 | |
8efc0c15 | 745 | #endif /* KRB4 */ |
746 | ||
747 | #ifdef AFS | |
5260325f | 748 | int |
749 | send_kerberos_tgt() | |
8efc0c15 | 750 | { |
5260325f | 751 | CREDENTIALS *creds; |
752 | char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; | |
753 | int r, type, plen; | |
754 | unsigned char buffer[8192]; | |
755 | struct stat st; | |
756 | ||
757 | /* Don't do anything if we don't have any tickets. */ | |
758 | if (stat(tkt_string(), &st) < 0) | |
759 | return 0; | |
760 | ||
761 | creds = xmalloc(sizeof(*creds)); | |
762 | ||
763 | if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) { | |
764 | debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]); | |
765 | return 0; | |
766 | } | |
767 | if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) { | |
768 | debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]); | |
769 | return 0; | |
770 | } | |
771 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { | |
772 | debug("Kerberos V4 ticket expired: %s", TKT_FILE); | |
773 | return 0; | |
774 | } | |
775 | creds_to_radix(creds, buffer); | |
776 | xfree(creds); | |
777 | ||
778 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
779 | packet_put_string((char *) buffer, strlen(buffer)); | |
780 | packet_send(); | |
781 | packet_write_wait(); | |
782 | ||
783 | type = packet_read(&plen); | |
784 | ||
785 | if (type == SSH_SMSG_FAILURE) | |
786 | debug("Kerberos TGT for realm %s rejected.", prealm); | |
787 | else if (type != SSH_SMSG_SUCCESS) | |
788 | packet_disconnect("Protocol error on Kerberos TGT response: %d", type); | |
789 | ||
790 | return 1; | |
8efc0c15 | 791 | } |
792 | ||
5260325f | 793 | void |
794 | send_afs_tokens(void) | |
8efc0c15 | 795 | { |
5260325f | 796 | CREDENTIALS creds; |
797 | struct ViceIoctl parms; | |
798 | struct ClearToken ct; | |
799 | int i, type, len, plen; | |
800 | char buf[2048], *p, *server_cell; | |
801 | unsigned char buffer[8192]; | |
802 | ||
803 | /* Move over ktc_GetToken, here's something leaner. */ | |
804 | for (i = 0; i < 100; i++) { /* just in case */ | |
805 | parms.in = (char *) &i; | |
806 | parms.in_size = sizeof(i); | |
807 | parms.out = buf; | |
808 | parms.out_size = sizeof(buf); | |
809 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
810 | break; | |
811 | p = buf; | |
812 | ||
813 | /* Get secret token. */ | |
814 | memcpy(&creds.ticket_st.length, p, sizeof(unsigned int)); | |
815 | if (creds.ticket_st.length > MAX_KTXT_LEN) | |
816 | break; | |
817 | p += sizeof(unsigned int); | |
818 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); | |
819 | p += creds.ticket_st.length; | |
820 | ||
821 | /* Get clear token. */ | |
822 | memcpy(&len, p, sizeof(len)); | |
823 | if (len != sizeof(struct ClearToken)) | |
824 | break; | |
825 | p += sizeof(len); | |
826 | memcpy(&ct, p, len); | |
827 | p += len; | |
828 | p += sizeof(len); /* primary flag */ | |
829 | server_cell = p; | |
830 | ||
831 | /* Flesh out our credentials. */ | |
832 | strlcpy(creds.service, "afs", sizeof creds.service); | |
833 | creds.instance[0] = '\0'; | |
834 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
835 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
836 | creds.issue_date = ct.BeginTimestamp; | |
837 | creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp); | |
838 | creds.kvno = ct.AuthHandle; | |
839 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
840 | creds.pinst[0] = '\0'; | |
841 | ||
842 | /* Encode token, ship it off. */ | |
843 | if (!creds_to_radix(&creds, buffer)) | |
844 | break; | |
845 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
846 | packet_put_string((char *) buffer, strlen(buffer)); | |
847 | packet_send(); | |
848 | packet_write_wait(); | |
849 | ||
850 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
851 | Victor? */ | |
852 | type = packet_read(&plen); | |
853 | ||
854 | if (type == SSH_SMSG_FAILURE) | |
855 | debug("AFS token for cell %s rejected.", server_cell); | |
856 | else if (type != SSH_SMSG_SUCCESS) | |
857 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
858 | } | |
8efc0c15 | 859 | } |
8efc0c15 | 860 | |
5260325f | 861 | #endif /* AFS */ |
8efc0c15 | 862 | |
57112b5a | 863 | /* |
864 | * Tries to authenticate with any string-based challenge/response system. | |
865 | * Note that the client code is not tied to s/key or TIS. | |
866 | */ | |
867 | int | |
868 | try_skey_authentication() | |
869 | { | |
870 | int type, i, payload_len; | |
871 | char *challenge, *response; | |
872 | ||
873 | debug("Doing skey authentication."); | |
874 | ||
875 | /* request a challenge */ | |
876 | packet_start(SSH_CMSG_AUTH_TIS); | |
877 | packet_send(); | |
878 | packet_write_wait(); | |
879 | ||
880 | type = packet_read(&payload_len); | |
881 | if (type != SSH_SMSG_FAILURE && | |
882 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
883 | packet_disconnect("Protocol error: got %d in response " | |
884 | "to skey-auth", type); | |
885 | } | |
886 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
887 | debug("No challenge for skey authentication."); | |
888 | return 0; | |
889 | } | |
890 | challenge = packet_get_string(&payload_len); | |
891 | if (options.cipher == SSH_CIPHER_NONE) | |
892 | log("WARNING: Encryption is disabled! " | |
893 | "Reponse will be transmitted in clear text."); | |
894 | fprintf(stderr, "%s\n", challenge); | |
c8d54615 | 895 | xfree(challenge); |
57112b5a | 896 | fflush(stderr); |
897 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
898 | if (i != 0) | |
899 | error("Permission denied, please try again."); | |
900 | response = read_passphrase("Response: ", 0); | |
901 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); | |
902 | packet_put_string(response, strlen(response)); | |
903 | memset(response, 0, strlen(response)); | |
904 | xfree(response); | |
905 | packet_send(); | |
906 | packet_write_wait(); | |
907 | type = packet_read(&payload_len); | |
908 | if (type == SSH_SMSG_SUCCESS) | |
909 | return 1; | |
910 | if (type != SSH_SMSG_FAILURE) | |
911 | packet_disconnect("Protocol error: got %d in response " | |
912 | "to skey-auth-reponse", type); | |
913 | } | |
914 | /* failure */ | |
915 | return 0; | |
916 | } | |
917 | ||
918 | /* | |
919 | * Tries to authenticate with plain passwd authentication. | |
920 | */ | |
921 | int | |
922 | try_password_authentication(char *prompt) | |
923 | { | |
924 | int type, i, payload_len; | |
925 | char *password; | |
926 | ||
927 | debug("Doing password authentication."); | |
928 | if (options.cipher == SSH_CIPHER_NONE) | |
929 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
930 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
931 | if (i != 0) | |
932 | error("Permission denied, please try again."); | |
933 | password = read_passphrase(prompt, 0); | |
934 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
935 | packet_put_string(password, strlen(password)); | |
936 | memset(password, 0, strlen(password)); | |
937 | xfree(password); | |
938 | packet_send(); | |
939 | packet_write_wait(); | |
940 | ||
941 | type = packet_read(&payload_len); | |
942 | if (type == SSH_SMSG_SUCCESS) | |
943 | return 1; | |
944 | if (type != SSH_SMSG_FAILURE) | |
945 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
946 | } | |
947 | /* failure */ | |
948 | return 0; | |
949 | } | |
950 | ||
5260325f | 951 | /* |
952 | * Waits for the server identification string, and sends our own | |
953 | * identification string. | |
954 | */ | |
955 | void | |
956 | ssh_exchange_identification() | |
8efc0c15 | 957 | { |
5260325f | 958 | char buf[256], remote_version[256]; /* must be same size! */ |
959 | int remote_major, remote_minor, i; | |
960 | int connection_in = packet_get_connection_in(); | |
961 | int connection_out = packet_get_connection_out(); | |
5260325f | 962 | |
963 | /* Read other side\'s version identification. */ | |
964 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
c8d54615 | 965 | int len = read(connection_in, &buf[i], 1); |
966 | if (len < 0) | |
5260325f | 967 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); |
c8d54615 | 968 | if (len != 1) |
969 | fatal("ssh_exchange_identification: Connection closed by remote host"); | |
5260325f | 970 | if (buf[i] == '\r') { |
971 | buf[i] = '\n'; | |
972 | buf[i + 1] = 0; | |
973 | break; | |
974 | } | |
975 | if (buf[i] == '\n') { | |
976 | buf[i + 1] = 0; | |
977 | break; | |
978 | } | |
8efc0c15 | 979 | } |
5260325f | 980 | buf[sizeof(buf) - 1] = 0; |
981 | ||
aa3378df | 982 | /* |
983 | * Check that the versions match. In future this might accept | |
984 | * several versions and set appropriate flags to handle them. | |
985 | */ | |
5260325f | 986 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
987 | remote_version) != 3) | |
988 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
989 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
990 | remote_major, remote_minor, remote_version); | |
991 | ||
992 | /* Check if the remote protocol version is too old. */ | |
993 | if (remote_major == 1 && remote_minor < 3) | |
994 | fatal("Remote machine has too old SSH software version."); | |
995 | ||
996 | /* We speak 1.3, too. */ | |
997 | if (remote_major == 1 && remote_minor == 3) { | |
998 | enable_compat13(); | |
7b2ea3a1 | 999 | if (options.forward_agent) { |
1000 | log("Agent forwarding disabled for protocol 1.3"); | |
5260325f | 1001 | options.forward_agent = 0; |
1002 | } | |
8efc0c15 | 1003 | } |
8efc0c15 | 1004 | #if 0 |
aa3378df | 1005 | /* |
1006 | * Removed for now, to permit compatibility with latter versions. The | |
1007 | * server will reject our version and disconnect if it doesn't | |
1008 | * support it. | |
1009 | */ | |
5260325f | 1010 | if (remote_major != PROTOCOL_MAJOR) |
1011 | fatal("Protocol major versions differ: %d vs. %d", | |
1012 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 1013 | #endif |
1014 | ||
5260325f | 1015 | /* Send our own protocol version identification. */ |
1016 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
a408af76 | 1017 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); |
1018 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) | |
5260325f | 1019 | fatal("write: %.100s", strerror(errno)); |
8efc0c15 | 1020 | } |
1021 | ||
1022 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
1023 | ||
5260325f | 1024 | int |
1025 | read_yes_or_no(const char *prompt, int defval) | |
8efc0c15 | 1026 | { |
5260325f | 1027 | char buf[1024]; |
1028 | FILE *f; | |
1029 | int retval = -1; | |
1030 | ||
1031 | if (isatty(0)) | |
1032 | f = stdin; | |
1033 | else | |
1034 | f = fopen("/dev/tty", "rw"); | |
1035 | ||
1036 | if (f == NULL) | |
1037 | return 0; | |
1038 | ||
1039 | fflush(stdout); | |
1040 | ||
1041 | while (1) { | |
1042 | fprintf(stderr, "%s", prompt); | |
1043 | if (fgets(buf, sizeof(buf), f) == NULL) { | |
1044 | /* Print a newline (the prompt probably didn\'t have one). */ | |
1045 | fprintf(stderr, "\n"); | |
1046 | strlcpy(buf, "no", sizeof buf); | |
1047 | } | |
1048 | /* Remove newline from response. */ | |
1049 | if (strchr(buf, '\n')) | |
1050 | *strchr(buf, '\n') = 0; | |
1051 | ||
1052 | if (buf[0] == 0) | |
1053 | retval = defval; | |
1054 | if (strcmp(buf, "yes") == 0) | |
1055 | retval = 1; | |
1056 | if (strcmp(buf, "no") == 0) | |
1057 | retval = 0; | |
1058 | ||
1059 | if (retval != -1) { | |
1060 | if (f != stdin) | |
1061 | fclose(f); | |
1062 | return retval; | |
1063 | } | |
8efc0c15 | 1064 | } |
8efc0c15 | 1065 | } |
1066 | ||
5260325f | 1067 | /* |
95f1eccc | 1068 | * check whether the supplied host key is valid, return only if ok. |
5260325f | 1069 | */ |
95f1eccc | 1070 | |
5260325f | 1071 | void |
48e671d5 | 1072 | check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key) |
8efc0c15 | 1073 | { |
95f1eccc | 1074 | RSA *file_key; |
1075 | char *ip = NULL; | |
5260325f | 1076 | char hostline[1000], *hostp; |
5260325f | 1077 | HostStatus host_status; |
1078 | HostStatus ip_status; | |
48e671d5 | 1079 | int local = 0, host_ip_differ = 0; |
20af321f | 1080 | int salen; |
48e671d5 | 1081 | char ntop[NI_MAXHOST]; |
1082 | ||
1083 | /* | |
1084 | * Force accepting of the host key for loopback/localhost. The | |
1085 | * problem is that if the home directory is NFS-mounted to multiple | |
1086 | * machines, localhost will refer to a different machine in each of | |
1087 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
1088 | * essentially disables host authentication for localhost; however, | |
1089 | * this is probably not a real problem. | |
1090 | */ | |
1091 | switch (hostaddr->sa_family) { | |
1092 | case AF_INET: | |
1093 | local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; | |
20af321f | 1094 | salen = sizeof(struct sockaddr_in); |
48e671d5 | 1095 | break; |
1096 | case AF_INET6: | |
1097 | local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
20af321f | 1098 | salen = sizeof(struct sockaddr_in6); |
48e671d5 | 1099 | break; |
1100 | default: | |
1101 | local = 0; | |
20af321f | 1102 | salen = sizeof(struct sockaddr_storage); |
48e671d5 | 1103 | break; |
1104 | } | |
1105 | if (local) { | |
1106 | debug("Forcing accepting of host key for loopback/localhost."); | |
1107 | return; | |
1108 | } | |
5260325f | 1109 | |
57112b5a | 1110 | /* |
1111 | * Turn off check_host_ip for proxy connects, since | |
1112 | * we don't have the remote ip-address | |
1113 | */ | |
1114 | if (options.proxy_command != NULL && options.check_host_ip) | |
1115 | options.check_host_ip = 0; | |
1116 | ||
48e671d5 | 1117 | if (options.check_host_ip) { |
20af321f | 1118 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), |
48e671d5 | 1119 | NULL, 0, NI_NUMERICHOST) != 0) |
1120 | fatal("check_host_key: getnameinfo failed"); | |
1121 | ip = xstrdup(ntop); | |
1122 | } | |
5260325f | 1123 | |
95f1eccc | 1124 | /* |
1125 | * Store the host key from the known host file in here so that we can | |
1126 | * compare it with the key for the IP address. | |
1127 | */ | |
5260325f | 1128 | file_key = RSA_new(); |
1129 | file_key->n = BN_new(); | |
1130 | file_key->e = BN_new(); | |
1131 | ||
aa3378df | 1132 | /* |
1133 | * Check if the host key is present in the user\'s list of known | |
1134 | * hosts or in the systemwide list. | |
1135 | */ | |
5260325f | 1136 | host_status = check_host_in_hostfile(options.user_hostfile, host, |
1137 | host_key->e, host_key->n, | |
1138 | file_key->e, file_key->n); | |
1139 | if (host_status == HOST_NEW) | |
1140 | host_status = check_host_in_hostfile(options.system_hostfile, host, | |
1141 | host_key->e, host_key->n, | |
1142 | file_key->e, file_key->n); | |
aa3378df | 1143 | /* |
1144 | * Also perform check for the ip address, skip the check if we are | |
1145 | * localhost or the hostname was an ip address to begin with | |
1146 | */ | |
5260325f | 1147 | if (options.check_host_ip && !local && strcmp(host, ip)) { |
1148 | RSA *ip_key = RSA_new(); | |
1149 | ip_key->n = BN_new(); | |
1150 | ip_key->e = BN_new(); | |
1151 | ip_status = check_host_in_hostfile(options.user_hostfile, ip, | |
1152 | host_key->e, host_key->n, | |
1153 | ip_key->e, ip_key->n); | |
1154 | ||
1155 | if (ip_status == HOST_NEW) | |
1156 | ip_status = check_host_in_hostfile(options.system_hostfile, ip, | |
1157 | host_key->e, host_key->n, | |
1158 | ip_key->e, ip_key->n); | |
1159 | if (host_status == HOST_CHANGED && | |
1160 | (ip_status != HOST_CHANGED || | |
1161 | (BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n)))) | |
1162 | host_ip_differ = 1; | |
1163 | ||
1164 | RSA_free(ip_key); | |
1165 | } else | |
1166 | ip_status = host_status; | |
1167 | ||
1168 | RSA_free(file_key); | |
1169 | ||
1170 | switch (host_status) { | |
1171 | case HOST_OK: | |
1172 | /* The host is known and the key matches. */ | |
1173 | debug("Host '%.200s' is known and matches the host key.", host); | |
1174 | if (options.check_host_ip) { | |
1175 | if (ip_status == HOST_NEW) { | |
1176 | if (!add_host_to_hostfile(options.user_hostfile, ip, | |
1177 | host_key->e, host_key->n)) | |
1178 | log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).", | |
1179 | ip, options.user_hostfile); | |
1180 | else | |
1181 | log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.", | |
1182 | ip); | |
1183 | } else if (ip_status != HOST_OK) | |
1184 | log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'", | |
1185 | host, ip); | |
1186 | } | |
1187 | break; | |
1188 | case HOST_NEW: | |
1189 | /* The host is new. */ | |
1190 | if (options.strict_host_key_checking == 1) { | |
1191 | /* User has requested strict host key checking. We will not add the host key | |
1192 | automatically. The only alternative left is to abort. */ | |
1193 | fatal("No host key is known for %.200s and you have requested strict checking.", host); | |
1194 | } else if (options.strict_host_key_checking == 2) { | |
1195 | /* The default */ | |
1196 | char prompt[1024]; | |
1197 | char *fp = fingerprint(host_key->e, host_key->n); | |
1198 | snprintf(prompt, sizeof(prompt), | |
a408af76 | 1199 | "The authenticity of host '%.200s' can't be established.\n" |
1200 | "Key fingerprint is %d %s.\n" | |
1201 | "Are you sure you want to continue connecting (yes/no)? ", | |
1202 | host, BN_num_bits(host_key->n), fp); | |
5260325f | 1203 | if (!read_yes_or_no(prompt, -1)) |
1204 | fatal("Aborted by user!\n"); | |
1205 | } | |
1206 | if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) { | |
1207 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); | |
1208 | hostp = hostline; | |
1209 | } else | |
1210 | hostp = host; | |
1211 | ||
1212 | /* If not in strict mode, add the key automatically to the local known_hosts file. */ | |
1213 | if (!add_host_to_hostfile(options.user_hostfile, hostp, | |
1214 | host_key->e, host_key->n)) | |
1215 | log("Failed to add the host to the list of known hosts (%.500s).", | |
1216 | options.user_hostfile); | |
1217 | else | |
1218 | log("Warning: Permanently added '%.200s' to the list of known hosts.", | |
1219 | hostp); | |
1220 | break; | |
1221 | case HOST_CHANGED: | |
1222 | if (options.check_host_ip && host_ip_differ) { | |
1223 | char *msg; | |
1224 | if (ip_status == HOST_NEW) | |
1225 | msg = "is unknown"; | |
1226 | else if (ip_status == HOST_OK) | |
1227 | msg = "is unchanged"; | |
1228 | else | |
1229 | msg = "has a different value"; | |
1230 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1231 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
1232 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1233 | error("The host key for %s has changed,", host); | |
1234 | error("and the key for the according IP address %s", ip); | |
1235 | error("%s. This could either mean that", msg); | |
1236 | error("DNS SPOOFING is happening or the IP address for the host"); | |
1237 | error("and its host key have changed at the same time"); | |
1238 | } | |
1239 | /* The host key has changed. */ | |
1240 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
ae2f7af7 | 1241 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
5260325f | 1242 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
1243 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1244 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1245 | error("It is also possible that the host key has just been changed."); | |
1246 | error("Please contact your system administrator."); | |
1247 | error("Add correct host key in %.100s to get rid of this message.", | |
1248 | options.user_hostfile); | |
1249 | ||
aa3378df | 1250 | /* |
1251 | * If strict host key checking is in use, the user will have | |
1252 | * to edit the key manually and we can only abort. | |
1253 | */ | |
5260325f | 1254 | if (options.strict_host_key_checking) |
1255 | fatal("Host key for %.200s has changed and you have requested strict checking.", host); | |
1256 | ||
aa3378df | 1257 | /* |
1258 | * If strict host key checking has not been requested, allow | |
1259 | * the connection but without password authentication or | |
1260 | * agent forwarding. | |
1261 | */ | |
5260325f | 1262 | if (options.password_authentication) { |
1263 | error("Password authentication is disabled to avoid trojan horses."); | |
1264 | options.password_authentication = 0; | |
1265 | } | |
1266 | if (options.forward_agent) { | |
1267 | error("Agent forwarding is disabled to avoid trojan horses."); | |
1268 | options.forward_agent = 0; | |
1269 | } | |
aa3378df | 1270 | /* |
1271 | * XXX Should permit the user to change to use the new id. | |
1272 | * This could be done by converting the host key to an | |
1273 | * identifying sentence, tell that the host identifies itself | |
1274 | * by that sentence, and ask the user if he/she whishes to | |
1275 | * accept the authentication. | |
1276 | */ | |
5260325f | 1277 | break; |
1278 | } | |
5260325f | 1279 | if (options.check_host_ip) |
1280 | xfree(ip); | |
95f1eccc | 1281 | } |
1282 | ||
1283 | /* | |
7b2ea3a1 | 1284 | * SSH1 key exchange |
95f1eccc | 1285 | */ |
1286 | void | |
7b2ea3a1 | 1287 | ssh_kex(char *host, struct sockaddr *hostaddr) |
95f1eccc | 1288 | { |
7b2ea3a1 | 1289 | int i; |
95f1eccc | 1290 | BIGNUM *key; |
1291 | RSA *host_key; | |
1292 | RSA *public_key; | |
1293 | int bits, rbits; | |
1294 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
7b2ea3a1 | 1295 | unsigned char cookie[8]; |
1296 | unsigned int supported_ciphers; | |
95f1eccc | 1297 | unsigned int server_flags, client_flags; |
1298 | int payload_len, clen, sum_len = 0; | |
1299 | u_int32_t rand = 0; | |
1300 | ||
95f1eccc | 1301 | debug("Waiting for server public key."); |
1302 | ||
1303 | /* Wait for a public key packet from the server. */ | |
1304 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
1305 | ||
7b2ea3a1 | 1306 | /* Get cookie from the packet. */ |
95f1eccc | 1307 | for (i = 0; i < 8; i++) |
7b2ea3a1 | 1308 | cookie[i] = packet_get_char(); |
95f1eccc | 1309 | |
1310 | /* Get the public key. */ | |
1311 | public_key = RSA_new(); | |
1312 | bits = packet_get_int();/* bits */ | |
1313 | public_key->e = BN_new(); | |
1314 | packet_get_bignum(public_key->e, &clen); | |
1315 | sum_len += clen; | |
1316 | public_key->n = BN_new(); | |
1317 | packet_get_bignum(public_key->n, &clen); | |
1318 | sum_len += clen; | |
1319 | ||
1320 | rbits = BN_num_bits(public_key->n); | |
1321 | if (bits != rbits) { | |
1322 | log("Warning: Server lies about size of server public key: " | |
1323 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1324 | log("Warning: This may be due to an old implementation of ssh."); | |
1325 | } | |
1326 | /* Get the host key. */ | |
1327 | host_key = RSA_new(); | |
1328 | bits = packet_get_int();/* bits */ | |
1329 | host_key->e = BN_new(); | |
1330 | packet_get_bignum(host_key->e, &clen); | |
1331 | sum_len += clen; | |
1332 | host_key->n = BN_new(); | |
1333 | packet_get_bignum(host_key->n, &clen); | |
1334 | sum_len += clen; | |
1335 | ||
1336 | rbits = BN_num_bits(host_key->n); | |
1337 | if (bits != rbits) { | |
1338 | log("Warning: Server lies about size of server host key: " | |
1339 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1340 | log("Warning: This may be due to an old implementation of ssh."); | |
1341 | } | |
1342 | ||
1343 | /* Get protocol flags. */ | |
1344 | server_flags = packet_get_int(); | |
1345 | packet_set_protocol_flags(server_flags); | |
1346 | ||
1347 | supported_ciphers = packet_get_int(); | |
1348 | supported_authentications = packet_get_int(); | |
1349 | ||
1350 | debug("Received server public key (%d bits) and host key (%d bits).", | |
1351 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
1352 | ||
1353 | packet_integrity_check(payload_len, | |
1354 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
1355 | SSH_SMSG_PUBLIC_KEY); | |
1356 | ||
1357 | check_host_key(host, hostaddr, host_key); | |
1358 | ||
1359 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; | |
1360 | ||
7b2ea3a1 | 1361 | compute_session_id(session_id, cookie, host_key->n, public_key->n); |
5260325f | 1362 | |
1363 | /* Generate a session key. */ | |
1364 | arc4random_stir(); | |
1365 | ||
aa3378df | 1366 | /* |
1367 | * Generate an encryption key for the session. The key is a 256 bit | |
1368 | * random number, interpreted as a 32-byte key, with the least | |
1369 | * significant 8 bits being the first byte of the key. | |
1370 | */ | |
5260325f | 1371 | for (i = 0; i < 32; i++) { |
1372 | if (i % 4 == 0) | |
1373 | rand = arc4random(); | |
1374 | session_key[i] = rand & 0xff; | |
1375 | rand >>= 8; | |
1376 | } | |
1377 | ||
aa3378df | 1378 | /* |
1379 | * According to the protocol spec, the first byte of the session key | |
1380 | * is the highest byte of the integer. The session key is xored with | |
1381 | * the first 16 bytes of the session id. | |
1382 | */ | |
5260325f | 1383 | key = BN_new(); |
1384 | BN_set_word(key, 0); | |
1385 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1386 | BN_lshift(key, key, 8); | |
1387 | if (i < 16) | |
1388 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1389 | else | |
1390 | BN_add_word(key, session_key[i]); | |
1391 | } | |
1392 | ||
aa3378df | 1393 | /* |
1394 | * Encrypt the integer using the public key and host key of the | |
1395 | * server (key with smaller modulus first). | |
1396 | */ | |
5260325f | 1397 | if (BN_cmp(public_key->n, host_key->n) < 0) { |
1398 | /* Public key has smaller modulus. */ | |
1399 | if (BN_num_bits(host_key->n) < | |
1400 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1401 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1402 | "SSH_KEY_BITS_RESERVED %d", | |
1403 | BN_num_bits(host_key->n), | |
1404 | BN_num_bits(public_key->n), | |
1405 | SSH_KEY_BITS_RESERVED); | |
1406 | } | |
1407 | rsa_public_encrypt(key, key, public_key); | |
1408 | rsa_public_encrypt(key, key, host_key); | |
1409 | } else { | |
1410 | /* Host key has smaller modulus (or they are equal). */ | |
1411 | if (BN_num_bits(public_key->n) < | |
1412 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1413 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1414 | "SSH_KEY_BITS_RESERVED %d", | |
1415 | BN_num_bits(public_key->n), | |
1416 | BN_num_bits(host_key->n), | |
1417 | SSH_KEY_BITS_RESERVED); | |
1418 | } | |
1419 | rsa_public_encrypt(key, key, host_key); | |
1420 | rsa_public_encrypt(key, key, public_key); | |
1421 | } | |
1422 | ||
7b2ea3a1 | 1423 | /* Destroy the public keys since we no longer need them. */ |
1424 | RSA_free(public_key); | |
1425 | RSA_free(host_key); | |
1426 | ||
5260325f | 1427 | if (options.cipher == SSH_CIPHER_NOT_SET) { |
1428 | if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default)) | |
1429 | options.cipher = ssh_cipher_default; | |
1430 | else { | |
1431 | debug("Cipher %s not supported, using %.100s instead.", | |
1432 | cipher_name(ssh_cipher_default), | |
1433 | cipher_name(SSH_FALLBACK_CIPHER)); | |
1434 | options.cipher = SSH_FALLBACK_CIPHER; | |
1435 | } | |
1436 | } | |
1437 | /* Check that the selected cipher is supported. */ | |
1438 | if (!(supported_ciphers & (1 << options.cipher))) | |
1439 | fatal("Selected cipher type %.100s not supported by server.", | |
1440 | cipher_name(options.cipher)); | |
1441 | ||
1442 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1443 | ||
1444 | /* Send the encrypted session key to the server. */ | |
1445 | packet_start(SSH_CMSG_SESSION_KEY); | |
1446 | packet_put_char(options.cipher); | |
1447 | ||
7b2ea3a1 | 1448 | /* Send the cookie back to the server. */ |
5260325f | 1449 | for (i = 0; i < 8; i++) |
7b2ea3a1 | 1450 | packet_put_char(cookie[i]); |
5260325f | 1451 | |
7b2ea3a1 | 1452 | /* Send and destroy the encrypted encryption key integer. */ |
5260325f | 1453 | packet_put_bignum(key); |
7b2ea3a1 | 1454 | BN_clear_free(key); |
5260325f | 1455 | |
1456 | /* Send protocol flags. */ | |
95f1eccc | 1457 | packet_put_int(client_flags); |
5260325f | 1458 | |
1459 | /* Send the packet now. */ | |
8efc0c15 | 1460 | packet_send(); |
1461 | packet_write_wait(); | |
5260325f | 1462 | |
5260325f | 1463 | debug("Sent encrypted session key."); |
1464 | ||
1465 | /* Set the encryption key. */ | |
1466 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1467 | ||
1468 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1469 | memset(session_key, 0, sizeof(session_key)); | |
1470 | ||
aa3378df | 1471 | /* |
1472 | * Expect a success message from the server. Note that this message | |
1473 | * will be received in encrypted form. | |
1474 | */ | |
5260325f | 1475 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); |
1476 | ||
1477 | debug("Received encrypted confirmation."); | |
7b2ea3a1 | 1478 | } |
1479 | ||
1480 | /* | |
1481 | * Authenticate user | |
1482 | */ | |
1483 | void | |
1484 | ssh_userauth(int host_key_valid, RSA *own_host_key, | |
1485 | uid_t original_real_uid, char *host) | |
1486 | { | |
1487 | int i, type; | |
1488 | int payload_len; | |
1489 | struct passwd *pw; | |
1490 | const char *server_user, *local_user; | |
1491 | ||
1492 | /* Get local user name. Use it as server user if no user name was given. */ | |
1493 | pw = getpwuid(original_real_uid); | |
1494 | if (!pw) | |
1495 | fatal("User id %d not found from user database.", original_real_uid); | |
1496 | local_user = xstrdup(pw->pw_name); | |
1497 | server_user = options.user ? options.user : local_user; | |
5260325f | 1498 | |
1499 | /* Send the name of the user to log in as on the server. */ | |
1500 | packet_start(SSH_CMSG_USER); | |
1501 | packet_put_string(server_user, strlen(server_user)); | |
1502 | packet_send(); | |
1503 | packet_write_wait(); | |
1504 | ||
aa3378df | 1505 | /* |
1506 | * The server should respond with success if no authentication is | |
1507 | * needed (the user has no password). Otherwise the server responds | |
1508 | * with failure. | |
1509 | */ | |
8efc0c15 | 1510 | type = packet_read(&payload_len); |
5260325f | 1511 | |
1512 | /* check whether the connection was accepted without authentication. */ | |
8efc0c15 | 1513 | if (type == SSH_SMSG_SUCCESS) |
5260325f | 1514 | return; |
8efc0c15 | 1515 | if (type != SSH_SMSG_FAILURE) |
5260325f | 1516 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", |
1517 | type); | |
1518 | ||
1519 | #ifdef AFS | |
1520 | /* Try Kerberos tgt passing if the server supports it. */ | |
1521 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1522 | options.kerberos_tgt_passing) { | |
1523 | if (options.cipher == SSH_CIPHER_NONE) | |
1524 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1525 | (void) send_kerberos_tgt(); | |
1526 | } | |
1527 | /* Try AFS token passing if the server supports it. */ | |
1528 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1529 | options.afs_token_passing && k_hasafs()) { | |
1530 | if (options.cipher == SSH_CIPHER_NONE) | |
1531 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1532 | send_afs_tokens(); | |
1533 | } | |
1534 | #endif /* AFS */ | |
8efc0c15 | 1535 | |
5260325f | 1536 | #ifdef KRB4 |
1537 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1538 | options.kerberos_authentication) { | |
1539 | debug("Trying Kerberos authentication."); | |
1540 | if (try_kerberos_authentication()) { | |
1541 | /* The server should respond with success or failure. */ | |
1542 | type = packet_read(&payload_len); | |
1543 | if (type == SSH_SMSG_SUCCESS) | |
1544 | return; | |
1545 | if (type != SSH_SMSG_FAILURE) | |
1546 | packet_disconnect("Protocol error: got %d in response to Kerberos auth", type); | |
1547 | } | |
1548 | } | |
1549 | #endif /* KRB4 */ | |
1550 | ||
aa3378df | 1551 | /* |
1552 | * Use rhosts authentication if running in privileged socket and we | |
1553 | * do not wish to remain anonymous. | |
1554 | */ | |
5260325f | 1555 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && |
1556 | options.rhosts_authentication) { | |
1557 | debug("Trying rhosts authentication."); | |
1558 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
1559 | packet_put_string(local_user, strlen(local_user)); | |
1560 | packet_send(); | |
1561 | packet_write_wait(); | |
1562 | ||
1563 | /* The server should respond with success or failure. */ | |
1564 | type = packet_read(&payload_len); | |
1565 | if (type == SSH_SMSG_SUCCESS) | |
1566 | return; | |
1567 | if (type != SSH_SMSG_FAILURE) | |
1568 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1569 | type); | |
1570 | } | |
aa3378df | 1571 | /* |
1572 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1573 | * authentication. | |
1574 | */ | |
5260325f | 1575 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && |
1576 | options.rhosts_rsa_authentication && host_key_valid) { | |
1577 | if (try_rhosts_rsa_authentication(local_user, own_host_key)) | |
1578 | return; | |
1579 | } | |
1580 | /* Try RSA authentication if the server supports it. */ | |
1581 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1582 | options.rsa_authentication) { | |
aa3378df | 1583 | /* |
1584 | * Try RSA authentication using the authentication agent. The | |
1585 | * agent is tried first because no passphrase is needed for | |
1586 | * it, whereas identity files may require passphrases. | |
1587 | */ | |
5260325f | 1588 | if (try_agent_authentication()) |
1589 | return; | |
1590 | ||
1591 | /* Try RSA authentication for each identity. */ | |
1592 | for (i = 0; i < options.num_identity_files; i++) | |
57112b5a | 1593 | if (try_rsa_authentication(options.identity_files[i])) |
5260325f | 1594 | return; |
1595 | } | |
1596 | /* Try skey authentication if the server supports it. */ | |
1597 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && | |
1598 | options.skey_authentication && !options.batch_mode) { | |
57112b5a | 1599 | if (try_skey_authentication()) |
1600 | return; | |
5260325f | 1601 | } |
1602 | /* Try password authentication if the server supports it. */ | |
1603 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1604 | options.password_authentication && !options.batch_mode) { | |
1605 | char prompt[80]; | |
a408af76 | 1606 | |
57112b5a | 1607 | snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
a408af76 | 1608 | server_user, host); |
57112b5a | 1609 | if (try_password_authentication(prompt)) |
1610 | return; | |
5260325f | 1611 | } |
1612 | /* All authentication methods have failed. Exit with an error message. */ | |
1613 | fatal("Permission denied."); | |
1614 | /* NOTREACHED */ | |
8efc0c15 | 1615 | } |
7b2ea3a1 | 1616 | |
1617 | /* | |
1618 | * Starts a dialog with the server, and authenticates the current user on the | |
1619 | * server. This does not need any extra privileges. The basic connection | |
1620 | * to the server must already have been established before this is called. | |
1621 | * If login fails, this function prints an error and never returns. | |
1622 | * This function does not require super-user privileges. | |
1623 | */ | |
1624 | void | |
1625 | ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost, | |
1626 | struct sockaddr *hostaddr, uid_t original_real_uid) | |
1627 | { | |
1628 | char *host, *cp; | |
1629 | ||
1630 | /* Convert the user-supplied hostname into all lowercase. */ | |
1631 | host = xstrdup(orighost); | |
1632 | for (cp = host; *cp; cp++) | |
1633 | if (isupper(*cp)) | |
1634 | *cp = tolower(*cp); | |
1635 | ||
1636 | /* Exchange protocol version identification strings with the server. */ | |
1637 | ssh_exchange_identification(); | |
1638 | ||
1639 | /* Put the connection into non-blocking mode. */ | |
1640 | packet_set_nonblocking(); | |
1641 | ||
1642 | supported_authentications = 0; | |
1643 | /* key exchange */ | |
1644 | ssh_kex(host, hostaddr); | |
1645 | if (supported_authentications == 0) | |
1646 | fatal("supported_authentications == 0."); | |
1647 | /* authenticate user */ | |
1648 | ssh_userauth(host_key_valid, own_host_key, original_real_uid, host); | |
1649 | } |