2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Functions for connecting the local authentication agent.
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
13 * SSH2 implementation,
14 * Copyright (c) 2000 Markus Friedl. All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 RCSID("$OpenBSD: authfd.c,v 1.45 2001/09/19 19:35:30 stevesk Exp $");
40 #include <openssl/evp.h>
57 int decode_reply(int type);
59 /* macro to check for "agent failure" message */
60 #define agent_failed(x) \
61 ((x == SSH_AGENT_FAILURE) || (x == SSH_COM_AGENT2_FAILURE) || \
62 (x == SSH2_AGENT_FAILURE))
64 /* Returns the number of the authentication fd, or -1 if there is none. */
67 ssh_get_authentication_socket(void)
69 const char *authsocket;
71 struct sockaddr_un sunaddr;
73 authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
77 sunaddr.sun_family = AF_UNIX;
78 strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
80 sock = socket(AF_UNIX, SOCK_STREAM, 0);
85 if (fcntl(sock, F_SETFD, 1) == -1) {
89 if (connect(sock, (struct sockaddr *) &sunaddr, sizeof sunaddr) < 0) {
97 ssh_request_reply(AuthenticationConnection *auth, Buffer *request, Buffer *reply)
102 /* Get the length of the message, and format it in the buffer. */
103 len = buffer_len(request);
106 /* Send the length and then the packet to the agent. */
107 if (atomicio(write, auth->fd, buf, 4) != 4 ||
108 atomicio(write, auth->fd, buffer_ptr(request),
109 buffer_len(request)) != buffer_len(request)) {
110 error("Error writing to authentication socket.");
114 * Wait for response from the agent. First read the length of the
119 l = read(auth->fd, buf + 4 - len, len);
120 if (l == -1 && (errno == EAGAIN || errno == EINTR))
123 error("Error reading response length from authentication socket.");
129 /* Extract the length, and check it for sanity. */
130 len = GET_32BIT(buf);
131 if (len > 256 * 1024)
132 fatal("Authentication response too long: %d", len);
134 /* Read the rest of the response in to the buffer. */
140 l = read(auth->fd, buf, l);
141 if (l == -1 && (errno == EAGAIN || errno == EINTR))
144 error("Error reading response from authentication socket.");
147 buffer_append(reply, (char *) buf, l);
154 * Closes the agent socket if it should be closed (depends on how it was
155 * obtained). The argument must have been returned by
156 * ssh_get_authentication_socket().
160 ssh_close_authentication_socket(int sock)
162 if (getenv(SSH_AUTHSOCKET_ENV_NAME))
167 * Opens and connects a private socket for communication with the
168 * authentication agent. Returns the file descriptor (which must be
169 * shut down and closed by the caller when no longer needed).
170 * Returns NULL if an error occurred and the connection could not be
174 AuthenticationConnection *
175 ssh_get_authentication_connection(void)
177 AuthenticationConnection *auth;
180 sock = ssh_get_authentication_socket();
183 * Fail if we couldn't obtain a connection. This happens if we
184 * exited due to a timeout.
189 auth = xmalloc(sizeof(*auth));
191 buffer_init(&auth->identities);
198 * Closes the connection to the authentication agent and frees any associated
203 ssh_close_authentication_connection(AuthenticationConnection *auth)
205 buffer_free(&auth->identities);
211 * Returns the first authentication identity held by the agent.
215 ssh_get_num_identities(AuthenticationConnection *auth, int version)
217 int type, code1 = 0, code2 = 0;
222 code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
223 code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
226 code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
227 code2 = SSH2_AGENT_IDENTITIES_ANSWER;
234 * Send a message to the agent requesting for a list of the
235 * identities it can represent.
237 buffer_init(&request);
238 buffer_put_char(&request, code1);
240 buffer_clear(&auth->identities);
241 if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
242 buffer_free(&request);
245 buffer_free(&request);
247 /* Get message type, and verify that we got a proper answer. */
248 type = buffer_get_char(&auth->identities);
249 if (agent_failed(type)) {
251 } else if (type != code2) {
252 fatal("Bad authentication reply message type: %d", type);
255 /* Get the number of entries in the response and check it for sanity. */
256 auth->howmany = buffer_get_int(&auth->identities);
257 if (auth->howmany > 1024)
258 fatal("Too many identities in authentication reply: %d",
261 return auth->howmany;
265 ssh_get_first_identity(AuthenticationConnection *auth, char **comment, int version)
267 /* get number of identities and return the first entry (if any). */
268 if (ssh_get_num_identities(auth, version) > 0)
269 return ssh_get_next_identity(auth, comment, version);
274 ssh_get_next_identity(AuthenticationConnection *auth, char **comment, int version)
281 /* Return failure if no more entries. */
282 if (auth->howmany <= 0)
286 * Get the next entry from the packet. These will abort with a fatal
287 * error if the packet is too short or contains corrupt data.
291 key = key_new(KEY_RSA1);
292 bits = buffer_get_int(&auth->identities);
293 buffer_get_bignum(&auth->identities, key->rsa->e);
294 buffer_get_bignum(&auth->identities, key->rsa->n);
295 *comment = buffer_get_string(&auth->identities, NULL);
296 if (bits != BN_num_bits(key->rsa->n))
297 log("Warning: identity keysize mismatch: actual %d, announced %u",
298 BN_num_bits(key->rsa->n), bits);
301 blob = buffer_get_string(&auth->identities, &blen);
302 *comment = buffer_get_string(&auth->identities, NULL);
303 key = key_from_blob(blob, blen);
310 /* Decrement the number of remaining entries. */
316 * Generates a random challenge, sends it to the agent, and waits for
317 * response from the agent. Returns true (non-zero) if the agent gave the
318 * correct answer, zero otherwise. Response type selects the style of
319 * response desired, with 0 corresponding to protocol version 1.0 (no longer
320 * supported) and 1 corresponding to protocol version 1.1.
324 ssh_decrypt_challenge(AuthenticationConnection *auth,
325 Key* key, BIGNUM *challenge,
326 u_char session_id[16],
335 if (key->type != KEY_RSA1)
337 if (response_type == 0) {
338 log("Compatibility with ssh protocol version 1.0 no longer supported.");
341 buffer_init(&buffer);
342 buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
343 buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
344 buffer_put_bignum(&buffer, key->rsa->e);
345 buffer_put_bignum(&buffer, key->rsa->n);
346 buffer_put_bignum(&buffer, challenge);
347 buffer_append(&buffer, (char *) session_id, 16);
348 buffer_put_int(&buffer, response_type);
350 if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
351 buffer_free(&buffer);
354 type = buffer_get_char(&buffer);
356 if (agent_failed(type)) {
357 log("Agent admitted failure to authenticate using the key.");
358 } else if (type != SSH_AGENT_RSA_RESPONSE) {
359 fatal("Bad authentication response: %d", type);
363 * Get the response from the packet. This will abort with a
364 * fatal error if the packet is corrupt.
366 for (i = 0; i < 16; i++)
367 response[i] = buffer_get_char(&buffer);
369 buffer_free(&buffer);
373 /* ask agent to sign data, returns -1 on error, 0 on success */
375 ssh_agent_sign(AuthenticationConnection *auth,
377 u_char **sigp, int *lenp,
378 u_char *data, int datalen)
380 extern int datafellows;
387 if (key_to_blob(key, &blob, &blen) == 0)
390 if (datafellows & SSH_BUG_SIGBLOB)
391 flags = SSH_AGENT_OLD_SIGNATURE;
394 buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
395 buffer_put_string(&msg, blob, blen);
396 buffer_put_string(&msg, data, datalen);
397 buffer_put_int(&msg, flags);
400 if (ssh_request_reply(auth, &msg, &msg) == 0) {
404 type = buffer_get_char(&msg);
405 if (agent_failed(type)) {
406 log("Agent admitted failure to sign using the key.");
407 } else if (type != SSH2_AGENT_SIGN_RESPONSE) {
408 fatal("Bad authentication response: %d", type);
411 *sigp = buffer_get_string(&msg, lenp);
417 /* Encode key for a message to the agent. */
420 ssh_encode_identity_rsa1(Buffer *b, RSA *key, const char *comment)
423 buffer_put_char(b, SSH_AGENTC_ADD_RSA_IDENTITY);
424 buffer_put_int(b, BN_num_bits(key->n));
425 buffer_put_bignum(b, key->n);
426 buffer_put_bignum(b, key->e);
427 buffer_put_bignum(b, key->d);
428 /* To keep within the protocol: p < q for ssh. in SSL p > q */
429 buffer_put_bignum(b, key->iqmp); /* ssh key->u */
430 buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
431 buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
432 buffer_put_cstring(b, comment);
436 ssh_encode_identity_ssh2(Buffer *b, Key *key, const char *comment)
439 buffer_put_char(b, SSH2_AGENTC_ADD_IDENTITY);
440 buffer_put_cstring(b, key_ssh_name(key));
443 buffer_put_bignum2(b, key->rsa->n);
444 buffer_put_bignum2(b, key->rsa->e);
445 buffer_put_bignum2(b, key->rsa->d);
446 buffer_put_bignum2(b, key->rsa->iqmp);
447 buffer_put_bignum2(b, key->rsa->p);
448 buffer_put_bignum2(b, key->rsa->q);
451 buffer_put_bignum2(b, key->dsa->p);
452 buffer_put_bignum2(b, key->dsa->q);
453 buffer_put_bignum2(b, key->dsa->g);
454 buffer_put_bignum2(b, key->dsa->pub_key);
455 buffer_put_bignum2(b, key->dsa->priv_key);
458 buffer_put_cstring(b, comment);
462 * Adds an identity to the authentication server. This call is not meant to
463 * be used by normal applications.
467 ssh_add_identity(AuthenticationConnection *auth, Key *key, const char *comment)
476 ssh_encode_identity_rsa1(&msg, key->rsa, comment);
480 ssh_encode_identity_ssh2(&msg, key, comment);
487 if (ssh_request_reply(auth, &msg, &msg) == 0) {
491 type = buffer_get_char(&msg);
493 return decode_reply(type);
497 * Removes an identity from the authentication server. This call is not
498 * meant to be used by normal applications.
502 ssh_remove_identity(AuthenticationConnection *auth, Key *key)
511 if (key->type == KEY_RSA1) {
512 buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
513 buffer_put_int(&msg, BN_num_bits(key->rsa->n));
514 buffer_put_bignum(&msg, key->rsa->e);
515 buffer_put_bignum(&msg, key->rsa->n);
516 } else if (key->type == KEY_DSA || key->type == KEY_RSA) {
517 key_to_blob(key, &blob, &blen);
518 buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
519 buffer_put_string(&msg, blob, blen);
525 if (ssh_request_reply(auth, &msg, &msg) == 0) {
529 type = buffer_get_char(&msg);
531 return decode_reply(type);
535 ssh_update_card(AuthenticationConnection *auth, int add, const char *reader_id)
541 buffer_put_char(&msg, add ? SSH_AGENTC_ADD_SMARTCARD_KEY :
542 SSH_AGENTC_REMOVE_SMARTCARD_KEY);
543 buffer_put_cstring(&msg, reader_id);
544 if (ssh_request_reply(auth, &msg, &msg) == 0) {
548 type = buffer_get_char(&msg);
550 return decode_reply(type);
554 * Removes all identities from the agent. This call is not meant to be used
555 * by normal applications.
559 ssh_remove_all_identities(AuthenticationConnection *auth, int version)
563 int code = (version==1) ?
564 SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
565 SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
568 buffer_put_char(&msg, code);
570 if (ssh_request_reply(auth, &msg, &msg) == 0) {
574 type = buffer_get_char(&msg);
576 return decode_reply(type);
580 decode_reply(int type)
583 case SSH_AGENT_FAILURE:
584 case SSH_COM_AGENT2_FAILURE:
585 case SSH2_AGENT_FAILURE:
586 log("SSH_AGENT_FAILURE");
588 case SSH_AGENT_SUCCESS:
591 fatal("Bad response from authentication agent: %d", type);