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 1.28 2000/09/21 11:07:50 markus Exp $");
47 #include <openssl/rsa.h>
48 #include <openssl/dsa.h>
49 #include <openssl/evp.h>
57 int decode_reply(int type);
59 /* Returns the number of the authentication fd, or -1 if there is none. */
62 ssh_get_authentication_socket()
64 const char *authsocket;
66 struct sockaddr_un sunaddr;
68 authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
72 sunaddr.sun_family = AF_UNIX;
73 strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
74 #ifdef HAVE_SUN_LEN_IN_SOCKADDR_UN
75 sunaddr.sun_len = len = SUN_LEN(&sunaddr)+1;
76 #else /* HAVE_SUN_LEN_IN_SOCKADDR_UN */
77 len = SUN_LEN(&sunaddr)+1;
78 #endif /* HAVE_SUN_LEN_IN_SOCKADDR_UN */
80 sock = socket(AF_UNIX, SOCK_STREAM, 0);
85 if (fcntl(sock, F_SETFD, 1) == -1) {
89 if (connect(sock, (struct sockaddr *) & sunaddr, len) < 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);
121 error("Error reading response length from authentication socket.");
127 /* Extract the length, and check it for sanity. */
128 len = GET_32BIT(buf);
129 if (len > 256 * 1024)
130 fatal("Authentication response too long: %d", len);
132 /* Read the rest of the response in to the buffer. */
138 l = read(auth->fd, buf, l);
140 error("Error reading response from authentication socket.");
143 buffer_append(reply, (char *) buf, l);
150 * Closes the agent socket if it should be closed (depends on how it was
151 * obtained). The argument must have been returned by
152 * ssh_get_authentication_socket().
156 ssh_close_authentication_socket(int sock)
158 if (getenv(SSH_AUTHSOCKET_ENV_NAME))
163 * Opens and connects a private socket for communication with the
164 * authentication agent. Returns the file descriptor (which must be
165 * shut down and closed by the caller when no longer needed).
166 * Returns NULL if an error occurred and the connection could not be
170 AuthenticationConnection *
171 ssh_get_authentication_connection()
173 AuthenticationConnection *auth;
176 sock = ssh_get_authentication_socket();
179 * Fail if we couldn't obtain a connection. This happens if we
180 * exited due to a timeout.
185 auth = xmalloc(sizeof(*auth));
187 buffer_init(&auth->identities);
194 * Closes the connection to the authentication agent and frees any associated
199 ssh_close_authentication_connection(AuthenticationConnection *auth)
201 buffer_free(&auth->identities);
207 * Returns the first authentication identity held by the agent.
211 ssh_get_first_identity(AuthenticationConnection *auth, char **comment, int version)
213 int type, code1 = 0, code2 = 0;
218 code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
219 code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
222 code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
223 code2 = SSH2_AGENT_IDENTITIES_ANSWER;
230 * Send a message to the agent requesting for a list of the
231 * identities it can represent.
233 buffer_init(&request);
234 buffer_put_char(&request, code1);
236 buffer_clear(&auth->identities);
237 if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
238 buffer_free(&request);
241 buffer_free(&request);
243 /* Get message type, and verify that we got a proper answer. */
244 type = buffer_get_char(&auth->identities);
245 if (type == SSH_AGENT_FAILURE) {
247 } else if (type != code2) {
248 fatal("Bad authentication reply message type: %d", type);
251 /* Get the number of entries in the response and check it for sanity. */
252 auth->howmany = buffer_get_int(&auth->identities);
253 if (auth->howmany > 1024)
254 fatal("Too many identities in authentication reply: %d\n",
257 /* Return the first entry (if any). */
258 return ssh_get_next_identity(auth, comment, version);
262 ssh_get_next_identity(AuthenticationConnection *auth, char **comment, int version)
269 /* Return failure if no more entries. */
270 if (auth->howmany <= 0)
274 * Get the next entry from the packet. These will abort with a fatal
275 * error if the packet is too short or contains corrupt data.
279 key = key_new(KEY_RSA);
280 bits = buffer_get_int(&auth->identities);
281 buffer_get_bignum(&auth->identities, key->rsa->e);
282 buffer_get_bignum(&auth->identities, key->rsa->n);
283 *comment = buffer_get_string(&auth->identities, NULL);
284 if (bits != BN_num_bits(key->rsa->n))
285 log("Warning: identity keysize mismatch: actual %d, announced %u",
286 BN_num_bits(key->rsa->n), bits);
289 blob = buffer_get_string(&auth->identities, &blen);
290 *comment = buffer_get_string(&auth->identities, NULL);
291 key = dsa_key_from_blob(blob, blen);
298 /* Decrement the number of remaining entries. */
304 * Generates a random challenge, sends it to the agent, and waits for
305 * response from the agent. Returns true (non-zero) if the agent gave the
306 * correct answer, zero otherwise. Response type selects the style of
307 * response desired, with 0 corresponding to protocol version 1.0 (no longer
308 * supported) and 1 corresponding to protocol version 1.1.
312 ssh_decrypt_challenge(AuthenticationConnection *auth,
313 Key* key, BIGNUM *challenge,
314 unsigned char session_id[16],
315 unsigned int response_type,
316 unsigned char response[16])
323 if (key->type != KEY_RSA)
325 if (response_type == 0) {
326 log("Compatibility with ssh protocol version 1.0 no longer supported.");
329 buffer_init(&buffer);
330 buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
331 buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
332 buffer_put_bignum(&buffer, key->rsa->e);
333 buffer_put_bignum(&buffer, key->rsa->n);
334 buffer_put_bignum(&buffer, challenge);
335 buffer_append(&buffer, (char *) session_id, 16);
336 buffer_put_int(&buffer, response_type);
338 if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
339 buffer_free(&buffer);
342 type = buffer_get_char(&buffer);
344 if (type == SSH_AGENT_FAILURE) {
345 log("Agent admitted failure to authenticate using the key.");
346 } else if (type != SSH_AGENT_RSA_RESPONSE) {
347 fatal("Bad authentication response: %d", type);
351 * Get the response from the packet. This will abort with a
352 * fatal error if the packet is corrupt.
354 for (i = 0; i < 16; i++)
355 response[i] = buffer_get_char(&buffer);
357 buffer_free(&buffer);
361 /* ask agent to sign data, returns -1 on error, 0 on success */
363 ssh_agent_sign(AuthenticationConnection *auth,
365 unsigned char **sigp, int *lenp,
366 unsigned char *data, int datalen)
368 extern int datafellows;
375 if (dsa_make_key_blob(key, &blob, &blen) == 0)
378 if (datafellows & SSH_BUG_SIGBLOB)
379 flags = SSH_AGENT_OLD_SIGNATURE;
382 buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
383 buffer_put_string(&msg, blob, blen);
384 buffer_put_string(&msg, data, datalen);
385 buffer_put_int(&msg, flags);
388 if (ssh_request_reply(auth, &msg, &msg) == 0) {
392 type = buffer_get_char(&msg);
393 if (type == SSH_AGENT_FAILURE) {
394 log("Agent admitted failure to sign using the key.");
395 } else if (type != SSH2_AGENT_SIGN_RESPONSE) {
396 fatal("Bad authentication response: %d", type);
399 *sigp = buffer_get_string(&msg, lenp);
405 /* Encode key for a message to the agent. */
408 ssh_encode_identity_rsa(Buffer *b, RSA *key, const char *comment)
411 buffer_put_char(b, SSH_AGENTC_ADD_RSA_IDENTITY);
412 buffer_put_int(b, BN_num_bits(key->n));
413 buffer_put_bignum(b, key->n);
414 buffer_put_bignum(b, key->e);
415 buffer_put_bignum(b, key->d);
416 /* To keep within the protocol: p < q for ssh. in SSL p > q */
417 buffer_put_bignum(b, key->iqmp); /* ssh key->u */
418 buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
419 buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
420 buffer_put_string(b, comment, strlen(comment));
424 ssh_encode_identity_dsa(Buffer *b, DSA *key, const char *comment)
427 buffer_put_char(b, SSH2_AGENTC_ADD_IDENTITY);
428 buffer_put_cstring(b, KEX_DSS);
429 buffer_put_bignum2(b, key->p);
430 buffer_put_bignum2(b, key->q);
431 buffer_put_bignum2(b, key->g);
432 buffer_put_bignum2(b, key->pub_key);
433 buffer_put_bignum2(b, key->priv_key);
434 buffer_put_string(b, comment, strlen(comment));
438 * Adds an identity to the authentication server. This call is not meant to
439 * be used by normal applications.
443 ssh_add_identity(AuthenticationConnection *auth, Key *key, const char *comment)
452 ssh_encode_identity_rsa(&msg, key->rsa, comment);
455 ssh_encode_identity_dsa(&msg, key->dsa, comment);
462 if (ssh_request_reply(auth, &msg, &msg) == 0) {
466 type = buffer_get_char(&msg);
468 return decode_reply(type);
472 * Removes an identity from the authentication server. This call is not
473 * meant to be used by normal applications.
477 ssh_remove_identity(AuthenticationConnection *auth, Key *key)
486 if (key->type == KEY_RSA) {
487 buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
488 buffer_put_int(&msg, BN_num_bits(key->rsa->n));
489 buffer_put_bignum(&msg, key->rsa->e);
490 buffer_put_bignum(&msg, key->rsa->n);
491 } else if (key->type == KEY_DSA) {
492 dsa_make_key_blob(key, &blob, &blen);
493 buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
494 buffer_put_string(&msg, blob, blen);
500 if (ssh_request_reply(auth, &msg, &msg) == 0) {
504 type = buffer_get_char(&msg);
506 return decode_reply(type);
510 * Removes all identities from the agent. This call is not meant to be used
511 * by normal applications.
515 ssh_remove_all_identities(AuthenticationConnection *auth, int version)
519 int code = (version==1) ?
520 SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
521 SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
524 buffer_put_char(&msg, code);
526 if (ssh_request_reply(auth, &msg, &msg) == 0) {
530 type = buffer_get_char(&msg);
532 return decode_reply(type);
536 decode_reply(int type)
539 case SSH_AGENT_FAILURE:
540 log("SSH_AGENT_FAILURE");
542 case SSH_AGENT_SUCCESS:
545 fatal("Bad response from authentication agent: %d", type);