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 1.36 2001/03/01 02:11:25 deraadt 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))
63 /* Returns the number of the authentication fd, or -1 if there is none. */
66 ssh_get_authentication_socket(void)
68 const char *authsocket;
70 struct sockaddr_un sunaddr;
72 authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
76 sunaddr.sun_family = AF_UNIX;
77 strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
78 len = SUN_LEN(&sunaddr)+1;
79 #ifdef HAVE_SUN_LEN_IN_SOCKADDR_UN
80 sunaddr.sun_len = len;
81 #endif /* HAVE_SUN_LEN_IN_SOCKADDR_UN */
83 sock = socket(AF_UNIX, SOCK_STREAM, 0);
88 if (fcntl(sock, F_SETFD, 1) == -1) {
92 if (connect(sock, (struct sockaddr *) & sunaddr, len) < 0) {
100 ssh_request_reply(AuthenticationConnection *auth, Buffer *request, Buffer *reply)
105 /* Get the length of the message, and format it in the buffer. */
106 len = buffer_len(request);
109 /* Send the length and then the packet to the agent. */
110 if (atomicio(write, auth->fd, buf, 4) != 4 ||
111 atomicio(write, auth->fd, buffer_ptr(request),
112 buffer_len(request)) != buffer_len(request)) {
113 error("Error writing to authentication socket.");
117 * Wait for response from the agent. First read the length of the
122 l = read(auth->fd, buf + 4 - len, len);
124 error("Error reading response length from authentication socket.");
130 /* Extract the length, and check it for sanity. */
131 len = GET_32BIT(buf);
132 if (len > 256 * 1024)
133 fatal("Authentication response too long: %d", len);
135 /* Read the rest of the response in to the buffer. */
141 l = read(auth->fd, buf, l);
143 error("Error reading response from authentication socket.");
146 buffer_append(reply, (char *) buf, l);
153 * Closes the agent socket if it should be closed (depends on how it was
154 * obtained). The argument must have been returned by
155 * ssh_get_authentication_socket().
159 ssh_close_authentication_socket(int sock)
161 if (getenv(SSH_AUTHSOCKET_ENV_NAME))
166 * Opens and connects a private socket for communication with the
167 * authentication agent. Returns the file descriptor (which must be
168 * shut down and closed by the caller when no longer needed).
169 * Returns NULL if an error occurred and the connection could not be
173 AuthenticationConnection *
174 ssh_get_authentication_connection(void)
176 AuthenticationConnection *auth;
179 sock = ssh_get_authentication_socket();
182 * Fail if we couldn't obtain a connection. This happens if we
183 * exited due to a timeout.
188 auth = xmalloc(sizeof(*auth));
190 buffer_init(&auth->identities);
197 * Closes the connection to the authentication agent and frees any associated
202 ssh_close_authentication_connection(AuthenticationConnection *auth)
204 buffer_free(&auth->identities);
210 * Returns the first authentication identity held by the agent.
214 ssh_get_num_identities(AuthenticationConnection *auth, int version)
216 int type, code1 = 0, code2 = 0;
221 code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
222 code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
225 code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
226 code2 = SSH2_AGENT_IDENTITIES_ANSWER;
233 * Send a message to the agent requesting for a list of the
234 * identities it can represent.
236 buffer_init(&request);
237 buffer_put_char(&request, code1);
239 buffer_clear(&auth->identities);
240 if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
241 buffer_free(&request);
244 buffer_free(&request);
246 /* Get message type, and verify that we got a proper answer. */
247 type = buffer_get_char(&auth->identities);
248 if (agent_failed(type)) {
250 } else if (type != code2) {
251 fatal("Bad authentication reply message type: %d", type);
254 /* Get the number of entries in the response and check it for sanity. */
255 auth->howmany = buffer_get_int(&auth->identities);
256 if (auth->howmany > 1024)
257 fatal("Too many identities in authentication reply: %d\n",
260 return auth->howmany;
264 ssh_get_first_identity(AuthenticationConnection *auth, char **comment, int version)
266 /* get number of identities and return the first entry (if any). */
267 if (ssh_get_num_identities(auth, version) > 0)
268 return ssh_get_next_identity(auth, comment, version);
273 ssh_get_next_identity(AuthenticationConnection *auth, char **comment, int version)
280 /* Return failure if no more entries. */
281 if (auth->howmany <= 0)
285 * Get the next entry from the packet. These will abort with a fatal
286 * error if the packet is too short or contains corrupt data.
290 key = key_new(KEY_RSA1);
291 bits = buffer_get_int(&auth->identities);
292 buffer_get_bignum(&auth->identities, key->rsa->e);
293 buffer_get_bignum(&auth->identities, key->rsa->n);
294 *comment = buffer_get_string(&auth->identities, NULL);
295 if (bits != BN_num_bits(key->rsa->n))
296 log("Warning: identity keysize mismatch: actual %d, announced %u",
297 BN_num_bits(key->rsa->n), bits);
300 blob = buffer_get_string(&auth->identities, &blen);
301 *comment = buffer_get_string(&auth->identities, NULL);
302 key = key_from_blob(blob, blen);
309 /* Decrement the number of remaining entries. */
315 * Generates a random challenge, sends it to the agent, and waits for
316 * response from the agent. Returns true (non-zero) if the agent gave the
317 * correct answer, zero otherwise. Response type selects the style of
318 * response desired, with 0 corresponding to protocol version 1.0 (no longer
319 * supported) and 1 corresponding to protocol version 1.1.
323 ssh_decrypt_challenge(AuthenticationConnection *auth,
324 Key* key, BIGNUM *challenge,
325 u_char session_id[16],
334 if (key->type != KEY_RSA1)
336 if (response_type == 0) {
337 log("Compatibility with ssh protocol version 1.0 no longer supported.");
340 buffer_init(&buffer);
341 buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
342 buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
343 buffer_put_bignum(&buffer, key->rsa->e);
344 buffer_put_bignum(&buffer, key->rsa->n);
345 buffer_put_bignum(&buffer, challenge);
346 buffer_append(&buffer, (char *) session_id, 16);
347 buffer_put_int(&buffer, response_type);
349 if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
350 buffer_free(&buffer);
353 type = buffer_get_char(&buffer);
355 if (agent_failed(type)) {
356 log("Agent admitted failure to authenticate using the key.");
357 } else if (type != SSH_AGENT_RSA_RESPONSE) {
358 fatal("Bad authentication response: %d", type);
362 * Get the response from the packet. This will abort with a
363 * fatal error if the packet is corrupt.
365 for (i = 0; i < 16; i++)
366 response[i] = buffer_get_char(&buffer);
368 buffer_free(&buffer);
372 /* ask agent to sign data, returns -1 on error, 0 on success */
374 ssh_agent_sign(AuthenticationConnection *auth,
376 u_char **sigp, int *lenp,
377 u_char *data, int datalen)
379 extern int datafellows;
386 if (key_to_blob(key, &blob, &blen) == 0)
389 if (datafellows & SSH_BUG_SIGBLOB)
390 flags = SSH_AGENT_OLD_SIGNATURE;
393 buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
394 buffer_put_string(&msg, blob, blen);
395 buffer_put_string(&msg, data, datalen);
396 buffer_put_int(&msg, flags);
399 if (ssh_request_reply(auth, &msg, &msg) == 0) {
403 type = buffer_get_char(&msg);
404 if (agent_failed(type)) {
405 log("Agent admitted failure to sign using the key.");
406 } else if (type != SSH2_AGENT_SIGN_RESPONSE) {
407 fatal("Bad authentication response: %d", type);
410 *sigp = buffer_get_string(&msg, lenp);
416 /* Encode key for a message to the agent. */
419 ssh_encode_identity_rsa1(Buffer *b, RSA *key, const char *comment)
422 buffer_put_char(b, SSH_AGENTC_ADD_RSA_IDENTITY);
423 buffer_put_int(b, BN_num_bits(key->n));
424 buffer_put_bignum(b, key->n);
425 buffer_put_bignum(b, key->e);
426 buffer_put_bignum(b, key->d);
427 /* To keep within the protocol: p < q for ssh. in SSL p > q */
428 buffer_put_bignum(b, key->iqmp); /* ssh key->u */
429 buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
430 buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
431 buffer_put_string(b, comment, strlen(comment));
435 ssh_encode_identity_ssh2(Buffer *b, Key *key, const char *comment)
438 buffer_put_char(b, SSH2_AGENTC_ADD_IDENTITY);
439 buffer_put_cstring(b, key_ssh_name(key));
442 buffer_put_bignum2(b, key->rsa->n);
443 buffer_put_bignum2(b, key->rsa->e);
444 buffer_put_bignum2(b, key->rsa->d);
445 buffer_put_bignum2(b, key->rsa->iqmp);
446 buffer_put_bignum2(b, key->rsa->p);
447 buffer_put_bignum2(b, key->rsa->q);
450 buffer_put_bignum2(b, key->dsa->p);
451 buffer_put_bignum2(b, key->dsa->q);
452 buffer_put_bignum2(b, key->dsa->g);
453 buffer_put_bignum2(b, key->dsa->pub_key);
454 buffer_put_bignum2(b, key->dsa->priv_key);
457 buffer_put_cstring(b, comment);
461 * Adds an identity to the authentication server. This call is not meant to
462 * be used by normal applications.
466 ssh_add_identity(AuthenticationConnection *auth, Key *key, const char *comment)
475 ssh_encode_identity_rsa1(&msg, key->rsa, comment);
479 ssh_encode_identity_ssh2(&msg, key, comment);
486 if (ssh_request_reply(auth, &msg, &msg) == 0) {
490 type = buffer_get_char(&msg);
492 return decode_reply(type);
496 * Removes an identity from the authentication server. This call is not
497 * meant to be used by normal applications.
501 ssh_remove_identity(AuthenticationConnection *auth, Key *key)
510 if (key->type == KEY_RSA1) {
511 buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
512 buffer_put_int(&msg, BN_num_bits(key->rsa->n));
513 buffer_put_bignum(&msg, key->rsa->e);
514 buffer_put_bignum(&msg, key->rsa->n);
515 } else if (key->type == KEY_DSA || key->type == KEY_RSA) {
516 key_to_blob(key, &blob, &blen);
517 buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
518 buffer_put_string(&msg, blob, blen);
524 if (ssh_request_reply(auth, &msg, &msg) == 0) {
528 type = buffer_get_char(&msg);
530 return decode_reply(type);
534 * Removes all identities from the agent. This call is not meant to be used
535 * by normal applications.
539 ssh_remove_all_identities(AuthenticationConnection *auth, int version)
543 int code = (version==1) ?
544 SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
545 SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
548 buffer_put_char(&msg, code);
550 if (ssh_request_reply(auth, &msg, &msg) == 0) {
554 type = buffer_get_char(&msg);
556 return decode_reply(type);
560 decode_reply(int type)
563 case SSH_AGENT_FAILURE:
564 case SSH_COM_AGENT2_FAILURE:
565 log("SSH_AGENT_FAILURE");
567 case SSH_AGENT_SUCCESS:
570 fatal("Bad response from authentication agent: %d", type);