xref: /openbsd/usr.bin/ssh/authfd.c (revision 0d001bbc)
1 /* $OpenBSD: authfd.c,v 1.99 2015/09/02 07:51:12 jsg Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@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 
39 #include <sys/types.h>
40 #include <sys/un.h>
41 #include <sys/socket.h>
42 
43 #include <fcntl.h>
44 #include <stdlib.h>
45 #include <signal.h>
46 #include <string.h>
47 #include <unistd.h>
48 #include <errno.h>
49 
50 #include "xmalloc.h"
51 #include "ssh.h"
52 #include "rsa.h"
53 #include "sshbuf.h"
54 #include "sshkey.h"
55 #include "authfd.h"
56 #include "cipher.h"
57 #include "compat.h"
58 #include "log.h"
59 #include "atomicio.h"
60 #include "misc.h"
61 #include "ssherr.h"
62 
63 #define MAX_AGENT_IDENTITIES	2048		/* Max keys in agent reply */
64 #define MAX_AGENT_REPLY_LEN	(256 * 1024) 	/* Max bytes in agent reply */
65 
66 /* macro to check for "agent failure" message */
67 #define agent_failed(x) \
68     ((x == SSH_AGENT_FAILURE) || \
69     (x == SSH_COM_AGENT2_FAILURE) || \
70     (x == SSH2_AGENT_FAILURE))
71 
72 /* Convert success/failure response from agent to a err.h status */
73 static int
74 decode_reply(u_char type)
75 {
76 	if (agent_failed(type))
77 		return SSH_ERR_AGENT_FAILURE;
78 	else if (type == SSH_AGENT_SUCCESS)
79 		return 0;
80 	else
81 		return SSH_ERR_INVALID_FORMAT;
82 }
83 
84 /* Returns the number of the authentication fd, or -1 if there is none. */
85 int
86 ssh_get_authentication_socket(int *fdp)
87 {
88 	const char *authsocket;
89 	int sock, oerrno;
90 	struct sockaddr_un sunaddr;
91 
92 	if (fdp != NULL)
93 		*fdp = -1;
94 
95 	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
96 	if (!authsocket)
97 		return SSH_ERR_AGENT_NOT_PRESENT;
98 
99 	memset(&sunaddr, 0, sizeof(sunaddr));
100 	sunaddr.sun_family = AF_UNIX;
101 	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
102 
103 	if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
104 		return SSH_ERR_SYSTEM_ERROR;
105 
106 	/* close on exec */
107 	if (fcntl(sock, F_SETFD, FD_CLOEXEC) == -1 ||
108 	    connect(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
109 		oerrno = errno;
110 		close(sock);
111 		errno = oerrno;
112 		return SSH_ERR_SYSTEM_ERROR;
113 	}
114 	if (fdp != NULL)
115 		*fdp = sock;
116 	else
117 		close(sock);
118 	return 0;
119 }
120 
121 /* Communicate with agent: send request and read reply */
122 static int
123 ssh_request_reply(int sock, struct sshbuf *request, struct sshbuf *reply)
124 {
125 	int r;
126 	size_t l, len;
127 	char buf[1024];
128 
129 	/* Get the length of the message, and format it in the buffer. */
130 	len = sshbuf_len(request);
131 	put_u32(buf, len);
132 
133 	/* Send the length and then the packet to the agent. */
134 	if (atomicio(vwrite, sock, buf, 4) != 4 ||
135 	    atomicio(vwrite, sock, (u_char *)sshbuf_ptr(request),
136 	    sshbuf_len(request)) != sshbuf_len(request))
137 		return SSH_ERR_AGENT_COMMUNICATION;
138 	/*
139 	 * Wait for response from the agent.  First read the length of the
140 	 * response packet.
141 	 */
142 	if (atomicio(read, sock, buf, 4) != 4)
143 	    return SSH_ERR_AGENT_COMMUNICATION;
144 
145 	/* Extract the length, and check it for sanity. */
146 	len = get_u32(buf);
147 	if (len > MAX_AGENT_REPLY_LEN)
148 		return SSH_ERR_INVALID_FORMAT;
149 
150 	/* Read the rest of the response in to the buffer. */
151 	sshbuf_reset(reply);
152 	while (len > 0) {
153 		l = len;
154 		if (l > sizeof(buf))
155 			l = sizeof(buf);
156 		if (atomicio(read, sock, buf, l) != l)
157 			return SSH_ERR_AGENT_COMMUNICATION;
158 		if ((r = sshbuf_put(reply, buf, l)) != 0)
159 			return r;
160 		len -= l;
161 	}
162 	return 0;
163 }
164 
165 /*
166  * Closes the agent socket if it should be closed (depends on how it was
167  * obtained).  The argument must have been returned by
168  * ssh_get_authentication_socket().
169  */
170 void
171 ssh_close_authentication_socket(int sock)
172 {
173 	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
174 		close(sock);
175 }
176 
177 /* Lock/unlock agent */
178 int
179 ssh_lock_agent(int sock, int lock, const char *password)
180 {
181 	int r;
182 	u_char type = lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK;
183 	struct sshbuf *msg;
184 
185 	if ((msg = sshbuf_new()) == NULL)
186 		return SSH_ERR_ALLOC_FAIL;
187 	if ((r = sshbuf_put_u8(msg, type)) != 0 ||
188 	    (r = sshbuf_put_cstring(msg, password)) != 0)
189 		goto out;
190 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
191 		goto out;
192 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
193 		goto out;
194 	r = decode_reply(type);
195  out:
196 	sshbuf_free(msg);
197 	return r;
198 }
199 
200 #ifdef WITH_SSH1
201 static int
202 deserialise_identity1(struct sshbuf *ids, struct sshkey **keyp, char **commentp)
203 {
204 	struct sshkey *key;
205 	int r, keybits;
206 	u_int32_t bits;
207 	char *comment = NULL;
208 
209 	if ((key = sshkey_new(KEY_RSA1)) == NULL)
210 		return SSH_ERR_ALLOC_FAIL;
211 	if ((r = sshbuf_get_u32(ids, &bits)) != 0 ||
212 	    (r = sshbuf_get_bignum1(ids, key->rsa->e)) != 0 ||
213 	    (r = sshbuf_get_bignum1(ids, key->rsa->n)) != 0 ||
214 	    (r = sshbuf_get_cstring(ids, &comment, NULL)) != 0)
215 		goto out;
216 	keybits = BN_num_bits(key->rsa->n);
217 	/* XXX previously we just warned here. I think we should be strict */
218 	if (keybits < 0 || bits != (u_int)keybits) {
219 		r = SSH_ERR_KEY_BITS_MISMATCH;
220 		goto out;
221 	}
222 	if (keyp != NULL) {
223 		*keyp = key;
224 		key = NULL;
225 	}
226 	if (commentp != NULL) {
227 		*commentp = comment;
228 		comment = NULL;
229 	}
230 	r = 0;
231  out:
232 	sshkey_free(key);
233 	free(comment);
234 	return r;
235 }
236 #endif
237 
238 static int
239 deserialise_identity2(struct sshbuf *ids, struct sshkey **keyp, char **commentp)
240 {
241 	int r;
242 	char *comment = NULL;
243 	const u_char *blob;
244 	size_t blen;
245 
246 	if ((r = sshbuf_get_string_direct(ids, &blob, &blen)) != 0 ||
247 	    (r = sshbuf_get_cstring(ids, &comment, NULL)) != 0)
248 		goto out;
249 	if ((r = sshkey_from_blob(blob, blen, keyp)) != 0)
250 		goto out;
251 	if (commentp != NULL) {
252 		*commentp = comment;
253 		comment = NULL;
254 	}
255 	r = 0;
256  out:
257 	free(comment);
258 	return r;
259 }
260 
261 /*
262  * Fetch list of identities held by the agent.
263  */
264 int
265 ssh_fetch_identitylist(int sock, int version, struct ssh_identitylist **idlp)
266 {
267 	u_char type, code1 = 0, code2 = 0;
268 	u_int32_t num, i;
269 	struct sshbuf *msg;
270 	struct ssh_identitylist *idl = NULL;
271 	int r;
272 
273 	/* Determine request and expected response types */
274 	switch (version) {
275 	case 1:
276 		code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
277 		code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
278 		break;
279 	case 2:
280 		code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
281 		code2 = SSH2_AGENT_IDENTITIES_ANSWER;
282 		break;
283 	default:
284 		return SSH_ERR_INVALID_ARGUMENT;
285 	}
286 
287 	/*
288 	 * Send a message to the agent requesting for a list of the
289 	 * identities it can represent.
290 	 */
291 	if ((msg = sshbuf_new()) == NULL)
292 		return SSH_ERR_ALLOC_FAIL;
293 	if ((r = sshbuf_put_u8(msg, code1)) != 0)
294 		goto out;
295 
296 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
297 		goto out;
298 
299 	/* Get message type, and verify that we got a proper answer. */
300 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
301 		goto out;
302 	if (agent_failed(type)) {
303 		r = SSH_ERR_AGENT_FAILURE;
304 		goto out;
305 	} else if (type != code2) {
306 		r = SSH_ERR_INVALID_FORMAT;
307 		goto out;
308 	}
309 
310 	/* Get the number of entries in the response and check it for sanity. */
311 	if ((r = sshbuf_get_u32(msg, &num)) != 0)
312 		goto out;
313 	if (num > MAX_AGENT_IDENTITIES) {
314 		r = SSH_ERR_INVALID_FORMAT;
315 		goto out;
316 	}
317 	if (num == 0) {
318 		r = SSH_ERR_AGENT_NO_IDENTITIES;
319 		goto out;
320 	}
321 
322 	/* Deserialise the response into a list of keys/comments */
323 	if ((idl = calloc(1, sizeof(*idl))) == NULL ||
324 	    (idl->keys = calloc(num, sizeof(*idl->keys))) == NULL ||
325 	    (idl->comments = calloc(num, sizeof(*idl->comments))) == NULL) {
326 		r = SSH_ERR_ALLOC_FAIL;
327 		goto out;
328 	}
329 	for (i = 0; i < num;) {
330 		switch (version) {
331 		case 1:
332 #ifdef WITH_SSH1
333 			if ((r = deserialise_identity1(msg,
334 			    &(idl->keys[i]), &(idl->comments[i]))) != 0)
335 				goto out;
336 #endif
337 			break;
338 		case 2:
339 			if ((r = deserialise_identity2(msg,
340 			    &(idl->keys[i]), &(idl->comments[i]))) != 0) {
341 				if (r == SSH_ERR_KEY_TYPE_UNKNOWN) {
342 					/* Gracefully skip unknown key types */
343 					num--;
344 					continue;
345 				} else
346 					goto out;
347 			}
348 			break;
349 		}
350 		i++;
351 	}
352 	idl->nkeys = num;
353 	*idlp = idl;
354 	idl = NULL;
355 	r = 0;
356  out:
357 	sshbuf_free(msg);
358 	if (idl != NULL)
359 		ssh_free_identitylist(idl);
360 	return r;
361 }
362 
363 void
364 ssh_free_identitylist(struct ssh_identitylist *idl)
365 {
366 	size_t i;
367 
368 	if (idl == NULL)
369 		return;
370 	for (i = 0; i < idl->nkeys; i++) {
371 		if (idl->keys != NULL)
372 			sshkey_free(idl->keys[i]);
373 		if (idl->comments != NULL)
374 			free(idl->comments[i]);
375 	}
376 	free(idl);
377 }
378 
379 /*
380  * Sends a challenge (typically from a server via ssh(1)) to the agent,
381  * and waits for a response from the agent.
382  * Returns true (non-zero) if the agent gave the correct answer, zero
383  * otherwise.
384  */
385 
386 #ifdef WITH_SSH1
387 int
388 ssh_decrypt_challenge(int sock, struct sshkey* key, BIGNUM *challenge,
389     u_char session_id[16], u_char response[16])
390 {
391 	struct sshbuf *msg;
392 	int r;
393 	u_char type;
394 
395 	if (key->type != KEY_RSA1)
396 		return SSH_ERR_INVALID_ARGUMENT;
397 	if ((msg = sshbuf_new()) == NULL)
398 		return SSH_ERR_ALLOC_FAIL;
399 	if ((r = sshbuf_put_u8(msg, SSH_AGENTC_RSA_CHALLENGE)) != 0 ||
400 	    (r = sshbuf_put_u32(msg, BN_num_bits(key->rsa->n))) != 0 ||
401 	    (r = sshbuf_put_bignum1(msg, key->rsa->e)) != 0 ||
402 	    (r = sshbuf_put_bignum1(msg, key->rsa->n)) != 0 ||
403 	    (r = sshbuf_put_bignum1(msg, challenge)) != 0 ||
404 	    (r = sshbuf_put(msg, session_id, 16)) != 0 ||
405 	    (r = sshbuf_put_u32(msg, 1)) != 0) /* Response type for proto 1.1 */
406 		goto out;
407 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
408 		goto out;
409 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
410 		goto out;
411 	if (agent_failed(type)) {
412 		r = SSH_ERR_AGENT_FAILURE;
413 		goto out;
414 	} else if (type != SSH_AGENT_RSA_RESPONSE) {
415 		r = SSH_ERR_INVALID_FORMAT;
416 		goto out;
417 	}
418 	if ((r = sshbuf_get(msg, response, 16)) != 0)
419 		goto out;
420 	r = 0;
421  out:
422 	sshbuf_free(msg);
423 	return r;
424 }
425 #endif
426 
427 /* ask agent to sign data, returns err.h code on error, 0 on success */
428 int
429 ssh_agent_sign(int sock, struct sshkey *key,
430     u_char **sigp, size_t *lenp,
431     const u_char *data, size_t datalen, u_int compat)
432 {
433 	struct sshbuf *msg;
434 	u_char *blob = NULL, type;
435 	size_t blen = 0, len = 0;
436 	u_int flags = 0;
437 	int r = SSH_ERR_INTERNAL_ERROR;
438 
439 	*sigp = NULL;
440 	*lenp = 0;
441 
442 	if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
443 		return SSH_ERR_INVALID_ARGUMENT;
444 	if (compat & SSH_BUG_SIGBLOB)
445 		flags |= SSH_AGENT_OLD_SIGNATURE;
446 	if ((msg = sshbuf_new()) == NULL)
447 		return SSH_ERR_ALLOC_FAIL;
448 	if ((r = sshkey_to_blob(key, &blob, &blen)) != 0)
449 		goto out;
450 	if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
451 	    (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
452 	    (r = sshbuf_put_string(msg, data, datalen)) != 0 ||
453 	    (r = sshbuf_put_u32(msg, flags)) != 0)
454 		goto out;
455 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
456 		goto out;
457 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
458 		goto out;
459 	if (agent_failed(type)) {
460 		r = SSH_ERR_AGENT_FAILURE;
461 		goto out;
462 	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
463 		r = SSH_ERR_INVALID_FORMAT;
464 		goto out;
465 	}
466 	if ((r = sshbuf_get_string(msg, sigp, &len)) != 0)
467 		goto out;
468 	*lenp = len;
469 	r = 0;
470  out:
471 	if (blob != NULL) {
472 		explicit_bzero(blob, blen);
473 		free(blob);
474 	}
475 	sshbuf_free(msg);
476 	return r;
477 }
478 
479 /* Encode key for a message to the agent. */
480 
481 #ifdef WITH_SSH1
482 static int
483 ssh_encode_identity_rsa1(struct sshbuf *b, RSA *key, const char *comment)
484 {
485 	int r;
486 
487 	/* To keep within the protocol: p < q for ssh. in SSL p > q */
488 	if ((r = sshbuf_put_u32(b, BN_num_bits(key->n))) != 0 ||
489 	    (r = sshbuf_put_bignum1(b, key->n)) != 0 ||
490 	    (r = sshbuf_put_bignum1(b, key->e)) != 0 ||
491 	    (r = sshbuf_put_bignum1(b, key->d)) != 0 ||
492 	    (r = sshbuf_put_bignum1(b, key->iqmp)) != 0 ||
493 	    (r = sshbuf_put_bignum1(b, key->q)) != 0 ||
494 	    (r = sshbuf_put_bignum1(b, key->p)) != 0 ||
495 	    (r = sshbuf_put_cstring(b, comment)) != 0)
496 		return r;
497 	return 0;
498 }
499 #endif
500 
501 static int
502 ssh_encode_identity_ssh2(struct sshbuf *b, struct sshkey *key,
503     const char *comment)
504 {
505 	int r;
506 
507 	if ((r = sshkey_private_serialize(key, b)) != 0 ||
508 	    (r = sshbuf_put_cstring(b, comment)) != 0)
509 		return r;
510 	return 0;
511 }
512 
513 static int
514 encode_constraints(struct sshbuf *m, u_int life, u_int confirm)
515 {
516 	int r;
517 
518 	if (life != 0) {
519 		if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_LIFETIME)) != 0 ||
520 		    (r = sshbuf_put_u32(m, life)) != 0)
521 			goto out;
522 	}
523 	if (confirm != 0) {
524 		if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_CONFIRM)) != 0)
525 			goto out;
526 	}
527 	r = 0;
528  out:
529 	return r;
530 }
531 
532 /*
533  * Adds an identity to the authentication server.
534  * This call is intended only for use by ssh-add(1) and like applications.
535  */
536 int
537 ssh_add_identity_constrained(int sock, struct sshkey *key, const char *comment,
538     u_int life, u_int confirm)
539 {
540 	struct sshbuf *msg;
541 	int r, constrained = (life || confirm);
542 	u_char type;
543 
544 	if ((msg = sshbuf_new()) == NULL)
545 		return SSH_ERR_ALLOC_FAIL;
546 
547 	switch (key->type) {
548 #ifdef WITH_SSH1
549 	case KEY_RSA1:
550 		type = constrained ?
551 		    SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
552 		    SSH_AGENTC_ADD_RSA_IDENTITY;
553 		if ((r = sshbuf_put_u8(msg, type)) != 0 ||
554 		    (r = ssh_encode_identity_rsa1(msg, key->rsa, comment)) != 0)
555 			goto out;
556 		break;
557 #endif
558 #ifdef WITH_OPENSSL
559 	case KEY_RSA:
560 	case KEY_RSA_CERT:
561 	case KEY_DSA:
562 	case KEY_DSA_CERT:
563 	case KEY_ECDSA:
564 	case KEY_ECDSA_CERT:
565 #endif
566 	case KEY_ED25519:
567 	case KEY_ED25519_CERT:
568 		type = constrained ?
569 		    SSH2_AGENTC_ADD_ID_CONSTRAINED :
570 		    SSH2_AGENTC_ADD_IDENTITY;
571 		if ((r = sshbuf_put_u8(msg, type)) != 0 ||
572 		    (r = ssh_encode_identity_ssh2(msg, key, comment)) != 0)
573 			goto out;
574 		break;
575 	default:
576 		r = SSH_ERR_INVALID_ARGUMENT;
577 		goto out;
578 	}
579 	if (constrained &&
580 	    (r = encode_constraints(msg, life, confirm)) != 0)
581 		goto out;
582 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
583 		goto out;
584 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
585 		goto out;
586 	r = decode_reply(type);
587  out:
588 	sshbuf_free(msg);
589 	return r;
590 }
591 
592 /*
593  * Removes an identity from the authentication server.
594  * This call is intended only for use by ssh-add(1) and like applications.
595  */
596 int
597 ssh_remove_identity(int sock, struct sshkey *key)
598 {
599 	struct sshbuf *msg;
600 	int r;
601 	u_char type, *blob = NULL;
602 	size_t blen;
603 
604 	if ((msg = sshbuf_new()) == NULL)
605 		return SSH_ERR_ALLOC_FAIL;
606 
607 #ifdef WITH_SSH1
608 	if (key->type == KEY_RSA1) {
609 		if ((r = sshbuf_put_u8(msg,
610 		    SSH_AGENTC_REMOVE_RSA_IDENTITY)) != 0 ||
611 		    (r = sshbuf_put_u32(msg, BN_num_bits(key->rsa->n))) != 0 ||
612 		    (r = sshbuf_put_bignum1(msg, key->rsa->e)) != 0 ||
613 		    (r = sshbuf_put_bignum1(msg, key->rsa->n)) != 0)
614 			goto out;
615 	} else
616 #endif
617 	if (key->type != KEY_UNSPEC) {
618 		if ((r = sshkey_to_blob(key, &blob, &blen)) != 0)
619 			goto out;
620 		if ((r = sshbuf_put_u8(msg,
621 		    SSH2_AGENTC_REMOVE_IDENTITY)) != 0 ||
622 		    (r = sshbuf_put_string(msg, blob, blen)) != 0)
623 			goto out;
624 	} else {
625 		r = SSH_ERR_INVALID_ARGUMENT;
626 		goto out;
627 	}
628 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
629 		goto out;
630 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
631 		goto out;
632 	r = decode_reply(type);
633  out:
634 	if (blob != NULL) {
635 		explicit_bzero(blob, blen);
636 		free(blob);
637 	}
638 	sshbuf_free(msg);
639 	return r;
640 }
641 
642 /*
643  * Add/remove an token-based identity from the authentication server.
644  * This call is intended only for use by ssh-add(1) and like applications.
645  */
646 int
647 ssh_update_card(int sock, int add, const char *reader_id, const char *pin,
648     u_int life, u_int confirm)
649 {
650 	struct sshbuf *msg;
651 	int r, constrained = (life || confirm);
652 	u_char type;
653 
654 	if (add) {
655 		type = constrained ?
656 		    SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED :
657 		    SSH_AGENTC_ADD_SMARTCARD_KEY;
658 	} else
659 		type = SSH_AGENTC_REMOVE_SMARTCARD_KEY;
660 
661 	if ((msg = sshbuf_new()) == NULL)
662 		return SSH_ERR_ALLOC_FAIL;
663 	if ((r = sshbuf_put_u8(msg, type)) != 0 ||
664 	    (r = sshbuf_put_cstring(msg, reader_id)) != 0 ||
665 	    (r = sshbuf_put_cstring(msg, pin)) != 0)
666 		goto out;
667 	if (constrained &&
668 	    (r = encode_constraints(msg, life, confirm)) != 0)
669 		goto out;
670 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
671 		goto out;
672 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
673 		goto out;
674 	r = decode_reply(type);
675  out:
676 	sshbuf_free(msg);
677 	return r;
678 }
679 
680 /*
681  * Removes all identities from the agent.
682  * This call is intended only for use by ssh-add(1) and like applications.
683  */
684 int
685 ssh_remove_all_identities(int sock, int version)
686 {
687 	struct sshbuf *msg;
688 	u_char type = (version == 1) ?
689 	    SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
690 	    SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
691 	int r;
692 
693 	if ((msg = sshbuf_new()) == NULL)
694 		return SSH_ERR_ALLOC_FAIL;
695 	if ((r = sshbuf_put_u8(msg, type)) != 0)
696 		goto out;
697 	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
698 		goto out;
699 	if ((r = sshbuf_get_u8(msg, &type)) != 0)
700 		goto out;
701 	r = decode_reply(type);
702  out:
703 	sshbuf_free(msg);
704 	return r;
705 }
706