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      1 /* $OpenBSD: authfd.c,v 1.86 2011/07/06 18:09:21 tedu Exp $ */
      2 /*
      3  * Author: Tatu Ylonen <ylo (at) cs.hut.fi>
      4  * Copyright (c) 1995 Tatu Ylonen <ylo (at) cs.hut.fi>, Espoo, Finland
      5  *                    All rights reserved
      6  * Functions for connecting the local authentication agent.
      7  *
      8  * As far as I am concerned, the code I have written for this software
      9  * can be used freely for any purpose.  Any derived versions of this
     10  * software must be clearly marked as such, and if the derived work is
     11  * incompatible with the protocol description in the RFC file, it must be
     12  * called by a name other than "ssh" or "Secure Shell".
     13  *
     14  * SSH2 implementation,
     15  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
     16  *
     17  * Redistribution and use in source and binary forms, with or without
     18  * modification, are permitted provided that the following conditions
     19  * are met:
     20  * 1. Redistributions of source code must retain the above copyright
     21  *    notice, this list of conditions and the following disclaimer.
     22  * 2. Redistributions in binary form must reproduce the above copyright
     23  *    notice, this list of conditions and the following disclaimer in the
     24  *    documentation and/or other materials provided with the distribution.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 #include "includes.h"
     39 
     40 #include <sys/types.h>
     41 #include <sys/un.h>
     42 #include <sys/socket.h>
     43 
     44 #include <openssl/evp.h>
     45 
     46 #include <openssl/crypto.h>
     47 #include <fcntl.h>
     48 #include <stdlib.h>
     49 #include <signal.h>
     50 #include <stdarg.h>
     51 #include <string.h>
     52 #include <unistd.h>
     53 
     54 #include "xmalloc.h"
     55 #include "ssh.h"
     56 #include "rsa.h"
     57 #include "buffer.h"
     58 #include "key.h"
     59 #include "authfd.h"
     60 #include "cipher.h"
     61 #include "kex.h"
     62 #include "compat.h"
     63 #include "log.h"
     64 #include "atomicio.h"
     65 #include "misc.h"
     66 
     67 static int agent_present = 0;
     68 
     69 /* helper */
     70 int	decode_reply(int type);
     71 
     72 /* macro to check for "agent failure" message */
     73 #define agent_failed(x) \
     74     ((x == SSH_AGENT_FAILURE) || (x == SSH_COM_AGENT2_FAILURE) || \
     75     (x == SSH2_AGENT_FAILURE))
     76 
     77 int
     78 ssh_agent_present(void)
     79 {
     80 	int authfd;
     81 
     82 	if (agent_present)
     83 		return 1;
     84 	if ((authfd = ssh_get_authentication_socket()) == -1)
     85 		return 0;
     86 	else {
     87 		ssh_close_authentication_socket(authfd);
     88 		return 1;
     89 	}
     90 }
     91 
     92 /* Returns the number of the authentication fd, or -1 if there is none. */
     93 
     94 int
     95 ssh_get_authentication_socket(void)
     96 {
     97 	const char *authsocket;
     98 	int sock;
     99 	struct sockaddr_un sunaddr;
    100 
    101 	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
    102 	if (!authsocket)
    103 		return -1;
    104 
    105 	bzero(&sunaddr, sizeof(sunaddr));
    106 	sunaddr.sun_family = AF_UNIX;
    107 	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
    108 
    109 	sock = socket(AF_UNIX, SOCK_STREAM, 0);
    110 	if (sock < 0)
    111 		return -1;
    112 
    113 	/* close on exec */
    114 	if (fcntl(sock, F_SETFD, FD_CLOEXEC) == -1) {
    115 		close(sock);
    116 		return -1;
    117 	}
    118 	if (connect(sock, (struct sockaddr *)&sunaddr, sizeof sunaddr) < 0) {
    119 		close(sock);
    120 		return -1;
    121 	}
    122 	agent_present = 1;
    123 	return sock;
    124 }
    125 
    126 static int
    127 ssh_request_reply(AuthenticationConnection *auth, Buffer *request, Buffer *reply)
    128 {
    129 	u_int l, len;
    130 	char buf[1024];
    131 
    132 	/* Get the length of the message, and format it in the buffer. */
    133 	len = buffer_len(request);
    134 	put_u32(buf, len);
    135 
    136 	/* Send the length and then the packet to the agent. */
    137 	if (atomicio(vwrite, auth->fd, buf, 4) != 4 ||
    138 	    atomicio(vwrite, auth->fd, buffer_ptr(request),
    139 	    buffer_len(request)) != buffer_len(request)) {
    140 		error("Error writing to authentication socket.");
    141 		return 0;
    142 	}
    143 	/*
    144 	 * Wait for response from the agent.  First read the length of the
    145 	 * response packet.
    146 	 */
    147 	if (atomicio(read, auth->fd, buf, 4) != 4) {
    148 	    error("Error reading response length from authentication socket.");
    149 	    return 0;
    150 	}
    151 
    152 	/* Extract the length, and check it for sanity. */
    153 	len = get_u32(buf);
    154 	if (len > 256 * 1024)
    155 		fatal("Authentication response too long: %u", len);
    156 
    157 	/* Read the rest of the response in to the buffer. */
    158 	buffer_clear(reply);
    159 	while (len > 0) {
    160 		l = len;
    161 		if (l > sizeof(buf))
    162 			l = sizeof(buf);
    163 		if (atomicio(read, auth->fd, buf, l) != l) {
    164 			error("Error reading response from authentication socket.");
    165 			return 0;
    166 		}
    167 		buffer_append(reply, buf, l);
    168 		len -= l;
    169 	}
    170 	return 1;
    171 }
    172 
    173 /*
    174  * Closes the agent socket if it should be closed (depends on how it was
    175  * obtained).  The argument must have been returned by
    176  * ssh_get_authentication_socket().
    177  */
    178 
    179 void
    180 ssh_close_authentication_socket(int sock)
    181 {
    182 	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
    183 		close(sock);
    184 }
    185 
    186 /*
    187  * Opens and connects a private socket for communication with the
    188  * authentication agent.  Returns the file descriptor (which must be
    189  * shut down and closed by the caller when no longer needed).
    190  * Returns NULL if an error occurred and the connection could not be
    191  * opened.
    192  */
    193 
    194 AuthenticationConnection *
    195 ssh_get_authentication_connection(void)
    196 {
    197 	AuthenticationConnection *auth;
    198 	int sock;
    199 
    200 	sock = ssh_get_authentication_socket();
    201 
    202 	/*
    203 	 * Fail if we couldn't obtain a connection.  This happens if we
    204 	 * exited due to a timeout.
    205 	 */
    206 	if (sock < 0)
    207 		return NULL;
    208 
    209 	auth = xmalloc(sizeof(*auth));
    210 	auth->fd = sock;
    211 	buffer_init(&auth->identities);
    212 	auth->howmany = 0;
    213 
    214 	return auth;
    215 }
    216 
    217 /*
    218  * Closes the connection to the authentication agent and frees any associated
    219  * memory.
    220  */
    221 
    222 void
    223 ssh_close_authentication_connection(AuthenticationConnection *auth)
    224 {
    225 	buffer_free(&auth->identities);
    226 	close(auth->fd);
    227 	xfree(auth);
    228 }
    229 
    230 /* Lock/unlock agent */
    231 int
    232 ssh_lock_agent(AuthenticationConnection *auth, int lock, const char *password)
    233 {
    234 	int type;
    235 	Buffer msg;
    236 
    237 	buffer_init(&msg);
    238 	buffer_put_char(&msg, lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK);
    239 	buffer_put_cstring(&msg, password);
    240 
    241 	if (ssh_request_reply(auth, &msg, &msg) == 0) {
    242 		buffer_free(&msg);
    243 		return 0;
    244 	}
    245 	type = buffer_get_char(&msg);
    246 	buffer_free(&msg);
    247 	return decode_reply(type);
    248 }
    249 
    250 /*
    251  * Returns the first authentication identity held by the agent.
    252  */
    253 
    254 int
    255 ssh_get_num_identities(AuthenticationConnection *auth, int version)
    256 {
    257 	int type, code1 = 0, code2 = 0;
    258 	Buffer request;
    259 
    260 	switch (version) {
    261 	case 1:
    262 		code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
    263 		code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
    264 		break;
    265 	case 2:
    266 		code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
    267 		code2 = SSH2_AGENT_IDENTITIES_ANSWER;
    268 		break;
    269 	default:
    270 		return 0;
    271 	}
    272 
    273 	/*
    274 	 * Send a message to the agent requesting for a list of the
    275 	 * identities it can represent.
    276 	 */
    277 	buffer_init(&request);
    278 	buffer_put_char(&request, code1);
    279 
    280 	buffer_clear(&auth->identities);
    281 	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
    282 		buffer_free(&request);
    283 		return 0;
    284 	}
    285 	buffer_free(&request);
    286 
    287 	/* Get message type, and verify that we got a proper answer. */
    288 	type = buffer_get_char(&auth->identities);
    289 	if (agent_failed(type)) {
    290 		return 0;
    291 	} else if (type != code2) {
    292 		fatal("Bad authentication reply message type: %d", type);
    293 	}
    294 
    295 	/* Get the number of entries in the response and check it for sanity. */
    296 	auth->howmany = buffer_get_int(&auth->identities);
    297 	if ((u_int)auth->howmany > 1024)
    298 		fatal("Too many identities in authentication reply: %d",
    299 		    auth->howmany);
    300 
    301 	return auth->howmany;
    302 }
    303 
    304 Key *
    305 ssh_get_first_identity(AuthenticationConnection *auth, char **comment, int version)
    306 {
    307 	/* get number of identities and return the first entry (if any). */
    308 	if (ssh_get_num_identities(auth, version) > 0)
    309 		return ssh_get_next_identity(auth, comment, version);
    310 	return NULL;
    311 }
    312 
    313 Key *
    314 ssh_get_next_identity(AuthenticationConnection *auth, char **comment, int version)
    315 {
    316 	int keybits;
    317 	u_int bits;
    318 	u_char *blob;
    319 	u_int blen;
    320 	Key *key = NULL;
    321 
    322 	/* Return failure if no more entries. */
    323 	if (auth->howmany <= 0)
    324 		return NULL;
    325 
    326 	/*
    327 	 * Get the next entry from the packet.  These will abort with a fatal
    328 	 * error if the packet is too short or contains corrupt data.
    329 	 */
    330 	switch (version) {
    331 	case 1:
    332 		key = key_new(KEY_RSA1);
    333 		bits = buffer_get_int(&auth->identities);
    334 		buffer_get_bignum(&auth->identities, key->rsa->e);
    335 		buffer_get_bignum(&auth->identities, key->rsa->n);
    336 		*comment = buffer_get_string(&auth->identities, NULL);
    337 		keybits = BN_num_bits(key->rsa->n);
    338 		if (keybits < 0 || bits != (u_int)keybits)
    339 			logit("Warning: identity keysize mismatch: actual %d, announced %u",
    340 			    BN_num_bits(key->rsa->n), bits);
    341 		break;
    342 	case 2:
    343 		blob = buffer_get_string(&auth->identities, &blen);
    344 		*comment = buffer_get_string(&auth->identities, NULL);
    345 		key = key_from_blob(blob, blen);
    346 		xfree(blob);
    347 		break;
    348 	default:
    349 		return NULL;
    350 	}
    351 	/* Decrement the number of remaining entries. */
    352 	auth->howmany--;
    353 	return key;
    354 }
    355 
    356 /*
    357  * Generates a random challenge, sends it to the agent, and waits for
    358  * response from the agent.  Returns true (non-zero) if the agent gave the
    359  * correct answer, zero otherwise.  Response type selects the style of
    360  * response desired, with 0 corresponding to protocol version 1.0 (no longer
    361  * supported) and 1 corresponding to protocol version 1.1.
    362  */
    363 
    364 int
    365 ssh_decrypt_challenge(AuthenticationConnection *auth,
    366     Key* key, BIGNUM *challenge,
    367     u_char session_id[16],
    368     u_int response_type,
    369     u_char response[16])
    370 {
    371 	Buffer buffer;
    372 	int success = 0;
    373 	int i;
    374 	int type;
    375 
    376 	if (key->type != KEY_RSA1)
    377 		return 0;
    378 	if (response_type == 0) {
    379 		logit("Compatibility with ssh protocol version 1.0 no longer supported.");
    380 		return 0;
    381 	}
    382 	buffer_init(&buffer);
    383 	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
    384 	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
    385 	buffer_put_bignum(&buffer, key->rsa->e);
    386 	buffer_put_bignum(&buffer, key->rsa->n);
    387 	buffer_put_bignum(&buffer, challenge);
    388 	buffer_append(&buffer, session_id, 16);
    389 	buffer_put_int(&buffer, response_type);
    390 
    391 	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
    392 		buffer_free(&buffer);
    393 		return 0;
    394 	}
    395 	type = buffer_get_char(&buffer);
    396 
    397 	if (agent_failed(type)) {
    398 		logit("Agent admitted failure to authenticate using the key.");
    399 	} else if (type != SSH_AGENT_RSA_RESPONSE) {
    400 		fatal("Bad authentication response: %d", type);
    401 	} else {
    402 		success = 1;
    403 		/*
    404 		 * Get the response from the packet.  This will abort with a
    405 		 * fatal error if the packet is corrupt.
    406 		 */
    407 		for (i = 0; i < 16; i++)
    408 			response[i] = (u_char)buffer_get_char(&buffer);
    409 	}
    410 	buffer_free(&buffer);
    411 	return success;
    412 }
    413 
    414 /* ask agent to sign data, returns -1 on error, 0 on success */
    415 int
    416 ssh_agent_sign(AuthenticationConnection *auth,
    417     Key *key,
    418     u_char **sigp, u_int *lenp,
    419     u_char *data, u_int datalen)
    420 {
    421 	extern int datafellows;
    422 	Buffer msg;
    423 	u_char *blob;
    424 	u_int blen;
    425 	int type, flags = 0;
    426 	int ret = -1;
    427 
    428 	if (key_to_blob(key, &blob, &blen) == 0)
    429 		return -1;
    430 
    431 	if (datafellows & SSH_BUG_SIGBLOB)
    432 		flags = SSH_AGENT_OLD_SIGNATURE;
    433 
    434 	buffer_init(&msg);
    435 	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
    436 	buffer_put_string(&msg, blob, blen);
    437 	buffer_put_string(&msg, data, datalen);
    438 	buffer_put_int(&msg, flags);
    439 	xfree(blob);
    440 
    441 	if (ssh_request_reply(auth, &msg, &msg) == 0) {
    442 		buffer_free(&msg);
    443 		return -1;
    444 	}
    445 	type = buffer_get_char(&msg);
    446 	if (agent_failed(type)) {
    447 		logit("Agent admitted failure to sign using the key.");
    448 	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
    449 		fatal("Bad authentication response: %d", type);
    450 	} else {
    451 		ret = 0;
    452 		*sigp = buffer_get_string(&msg, lenp);
    453 	}
    454 	buffer_free(&msg);
    455 	return ret;
    456 }
    457 
    458 /* Encode key for a message to the agent. */
    459 
    460 static void
    461 ssh_encode_identity_rsa1(Buffer *b, RSA *key, const char *comment)
    462 {
    463 	buffer_put_int(b, BN_num_bits(key->n));
    464 	buffer_put_bignum(b, key->n);
    465 	buffer_put_bignum(b, key->e);
    466 	buffer_put_bignum(b, key->d);
    467 	/* To keep within the protocol: p < q for ssh. in SSL p > q */
    468 	buffer_put_bignum(b, key->iqmp);	/* ssh key->u */
    469 	buffer_put_bignum(b, key->q);	/* ssh key->p, SSL key->q */
    470 	buffer_put_bignum(b, key->p);	/* ssh key->q, SSL key->p */
    471 	buffer_put_cstring(b, comment);
    472 }
    473 
    474 static void
    475 ssh_encode_identity_ssh2(Buffer *b, Key *key, const char *comment)
    476 {
    477 	buffer_put_cstring(b, key_ssh_name(key));
    478 	switch (key->type) {
    479 	case KEY_RSA:
    480 		buffer_put_bignum2(b, key->rsa->n);
    481 		buffer_put_bignum2(b, key->rsa->e);
    482 		buffer_put_bignum2(b, key->rsa->d);
    483 		buffer_put_bignum2(b, key->rsa->iqmp);
    484 		buffer_put_bignum2(b, key->rsa->p);
    485 		buffer_put_bignum2(b, key->rsa->q);
    486 		break;
    487 	case KEY_RSA_CERT_V00:
    488 	case KEY_RSA_CERT:
    489 		if (key->cert == NULL || buffer_len(&key->cert->certblob) == 0)
    490 			fatal("%s: no cert/certblob", __func__);
    491 		buffer_put_string(b, buffer_ptr(&key->cert->certblob),
    492 		    buffer_len(&key->cert->certblob));
    493 		buffer_put_bignum2(b, key->rsa->d);
    494 		buffer_put_bignum2(b, key->rsa->iqmp);
    495 		buffer_put_bignum2(b, key->rsa->p);
    496 		buffer_put_bignum2(b, key->rsa->q);
    497 		break;
    498 	case KEY_DSA:
    499 		buffer_put_bignum2(b, key->dsa->p);
    500 		buffer_put_bignum2(b, key->dsa->q);
    501 		buffer_put_bignum2(b, key->dsa->g);
    502 		buffer_put_bignum2(b, key->dsa->pub_key);
    503 		buffer_put_bignum2(b, key->dsa->priv_key);
    504 		break;
    505 	case KEY_DSA_CERT_V00:
    506 	case KEY_DSA_CERT:
    507 		if (key->cert == NULL || buffer_len(&key->cert->certblob) == 0)
    508 			fatal("%s: no cert/certblob", __func__);
    509 		buffer_put_string(b, buffer_ptr(&key->cert->certblob),
    510 		    buffer_len(&key->cert->certblob));
    511 		buffer_put_bignum2(b, key->dsa->priv_key);
    512 		break;
    513 #ifdef OPENSSL_HAS_ECC
    514 	case KEY_ECDSA:
    515 		buffer_put_cstring(b, key_curve_nid_to_name(key->ecdsa_nid));
    516 		buffer_put_ecpoint(b, EC_KEY_get0_group(key->ecdsa),
    517 		    EC_KEY_get0_public_key(key->ecdsa));
    518 		buffer_put_bignum2(b, EC_KEY_get0_private_key(key->ecdsa));
    519 		break;
    520 	case KEY_ECDSA_CERT:
    521 		if (key->cert == NULL || buffer_len(&key->cert->certblob) == 0)
    522 			fatal("%s: no cert/certblob", __func__);
    523 		buffer_put_string(b, buffer_ptr(&key->cert->certblob),
    524 		    buffer_len(&key->cert->certblob));
    525 		buffer_put_bignum2(b, EC_KEY_get0_private_key(key->ecdsa));
    526 		break;
    527 #endif
    528 	}
    529 	buffer_put_cstring(b, comment);
    530 }
    531 
    532 /*
    533  * Adds an identity to the authentication server.  This call is not meant to
    534  * be used by normal applications.
    535  */
    536 
    537 int
    538 ssh_add_identity_constrained(AuthenticationConnection *auth, Key *key,
    539     const char *comment, u_int life, u_int confirm)
    540 {
    541 	Buffer msg;
    542 	int type, constrained = (life || confirm);
    543 
    544 	buffer_init(&msg);
    545 
    546 	switch (key->type) {
    547 	case KEY_RSA1:
    548 		type = constrained ?
    549 		    SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
    550 		    SSH_AGENTC_ADD_RSA_IDENTITY;
    551 		buffer_put_char(&msg, type);
    552 		ssh_encode_identity_rsa1(&msg, key->rsa, comment);
    553 		break;
    554 	case KEY_RSA:
    555 	case KEY_RSA_CERT:
    556 	case KEY_RSA_CERT_V00:
    557 	case KEY_DSA:
    558 	case KEY_DSA_CERT:
    559 	case KEY_DSA_CERT_V00:
    560 	case KEY_ECDSA:
    561 	case KEY_ECDSA_CERT:
    562 		type = constrained ?
    563 		    SSH2_AGENTC_ADD_ID_CONSTRAINED :
    564 		    SSH2_AGENTC_ADD_IDENTITY;
    565 		buffer_put_char(&msg, type);
    566 		ssh_encode_identity_ssh2(&msg, key, comment);
    567 		break;
    568 	default:
    569 		buffer_free(&msg);
    570 		return 0;
    571 	}
    572 	if (constrained) {
    573 		if (life != 0) {
    574 			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
    575 			buffer_put_int(&msg, life);
    576 		}
    577 		if (confirm != 0)
    578 			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
    579 	}
    580 	if (ssh_request_reply(auth, &msg, &msg) == 0) {
    581 		buffer_free(&msg);
    582 		return 0;
    583 	}
    584 	type = buffer_get_char(&msg);
    585 	buffer_free(&msg);
    586 	return decode_reply(type);
    587 }
    588 
    589 /*
    590  * Removes an identity from the authentication server.  This call is not
    591  * meant to be used by normal applications.
    592  */
    593 
    594 int
    595 ssh_remove_identity(AuthenticationConnection *auth, Key *key)
    596 {
    597 	Buffer msg;
    598 	int type;
    599 	u_char *blob;
    600 	u_int blen;
    601 
    602 	buffer_init(&msg);
    603 
    604 	if (key->type == KEY_RSA1) {
    605 		buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
    606 		buffer_put_int(&msg, BN_num_bits(key->rsa->n));
    607 		buffer_put_bignum(&msg, key->rsa->e);
    608 		buffer_put_bignum(&msg, key->rsa->n);
    609 	} else if (key_type_plain(key->type) == KEY_DSA ||
    610 	    key_type_plain(key->type) == KEY_RSA ||
    611 	    key_type_plain(key->type) == KEY_ECDSA) {
    612 		key_to_blob(key, &blob, &blen);
    613 		buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
    614 		buffer_put_string(&msg, blob, blen);
    615 		xfree(blob);
    616 	} else {
    617 		buffer_free(&msg);
    618 		return 0;
    619 	}
    620 	if (ssh_request_reply(auth, &msg, &msg) == 0) {
    621 		buffer_free(&msg);
    622 		return 0;
    623 	}
    624 	type = buffer_get_char(&msg);
    625 	buffer_free(&msg);
    626 	return decode_reply(type);
    627 }
    628 
    629 int
    630 ssh_update_card(AuthenticationConnection *auth, int add,
    631     const char *reader_id, const char *pin, u_int life, u_int confirm)
    632 {
    633 	Buffer msg;
    634 	int type, constrained = (life || confirm);
    635 
    636 	if (add) {
    637 		type = constrained ?
    638 		    SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED :
    639 		    SSH_AGENTC_ADD_SMARTCARD_KEY;
    640 	} else
    641 		type = SSH_AGENTC_REMOVE_SMARTCARD_KEY;
    642 
    643 	buffer_init(&msg);
    644 	buffer_put_char(&msg, type);
    645 	buffer_put_cstring(&msg, reader_id);
    646 	buffer_put_cstring(&msg, pin);
    647 
    648 	if (constrained) {
    649 		if (life != 0) {
    650 			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
    651 			buffer_put_int(&msg, life);
    652 		}
    653 		if (confirm != 0)
    654 			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
    655 	}
    656 
    657 	if (ssh_request_reply(auth, &msg, &msg) == 0) {
    658 		buffer_free(&msg);
    659 		return 0;
    660 	}
    661 	type = buffer_get_char(&msg);
    662 	buffer_free(&msg);
    663 	return decode_reply(type);
    664 }
    665 
    666 /*
    667  * Removes all identities from the agent.  This call is not meant to be used
    668  * by normal applications.
    669  */
    670 
    671 int
    672 ssh_remove_all_identities(AuthenticationConnection *auth, int version)
    673 {
    674 	Buffer msg;
    675 	int type;
    676 	int code = (version==1) ?
    677 		SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
    678 		SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
    679 
    680 	buffer_init(&msg);
    681 	buffer_put_char(&msg, code);
    682 
    683 	if (ssh_request_reply(auth, &msg, &msg) == 0) {
    684 		buffer_free(&msg);
    685 		return 0;
    686 	}
    687 	type = buffer_get_char(&msg);
    688 	buffer_free(&msg);
    689 	return decode_reply(type);
    690 }
    691 
    692 int
    693 decode_reply(int type)
    694 {
    695 	switch (type) {
    696 	case SSH_AGENT_FAILURE:
    697 	case SSH_COM_AGENT2_FAILURE:
    698 	case SSH2_AGENT_FAILURE:
    699 		logit("SSH_AGENT_FAILURE");
    700 		return 0;
    701 	case SSH_AGENT_SUCCESS:
    702 		return 1;
    703 	default:
    704 		fatal("Bad response from authentication agent: %d", type);
    705 	}
    706 	/* NOTREACHED */
    707 	return 0;
    708 }
    709