summaryrefslogtreecommitdiff
path: root/authfd.c
blob: 5d9414faf543af60cd9f0062ca725e39702c5c4c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
/* $OpenBSD: authfd.c,v 1.94 2015/01/14 20:05:27 djm Exp $ */
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * Functions for connecting the local authentication agent.
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 *
 * SSH2 implementation,
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>
#include <sys/un.h>
#include <sys/socket.h>

#include <fcntl.h>
#include <stdlib.h>
#include <signal.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include "xmalloc.h"
#include "ssh.h"
#include "rsa.h"
#include "sshbuf.h"
#include "sshkey.h"
#include "authfd.h"
#include "cipher.h"
#include "compat.h"
#include "log.h"
#include "atomicio.h"
#include "misc.h"
#include "ssherr.h"

#define MAX_AGENT_IDENTITIES	2048		/* Max keys in agent reply */
#define MAX_AGENT_REPLY_LEN	(256 * 1024) 	/* Max bytes in agent reply */

/* macro to check for "agent failure" message */
#define agent_failed(x) \
    ((x == SSH_AGENT_FAILURE) || \
    (x == SSH_COM_AGENT2_FAILURE) || \
    (x == SSH2_AGENT_FAILURE))

/* Convert success/failure response from agent to a err.h status */
static int
decode_reply(u_char type)
{
	if (agent_failed(type))
		return SSH_ERR_AGENT_FAILURE;
	else if (type == SSH_AGENT_SUCCESS)
		return 0;
	else
		return SSH_ERR_INVALID_FORMAT;
}

/* Returns the number of the authentication fd, or -1 if there is none. */
int
ssh_get_authentication_socket(int *fdp)
{
	const char *authsocket;
	int sock, oerrno;
	struct sockaddr_un sunaddr;

	if (fdp != NULL)
		*fdp = -1;

	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
	if (!authsocket)
		return SSH_ERR_AGENT_NOT_PRESENT;

	memset(&sunaddr, 0, sizeof(sunaddr));
	sunaddr.sun_family = AF_UNIX;
	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));

	if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
		return SSH_ERR_SYSTEM_ERROR;

	/* close on exec */
	if (fcntl(sock, F_SETFD, FD_CLOEXEC) == -1 ||
	    connect(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
		oerrno = errno;
		close(sock);
		errno = oerrno;
		return SSH_ERR_SYSTEM_ERROR;
	}
	if (fdp != NULL)
		*fdp = sock;
	else
		close(sock);
	return 0;
}

/* Communicate with agent: send request and read reply */
static int
ssh_request_reply(int sock, struct sshbuf *request, struct sshbuf *reply)
{
	int r;
	size_t l, len;
	char buf[1024];

	/* Get the length of the message, and format it in the buffer. */
	len = sshbuf_len(request);
	put_u32(buf, len);

	/* Send the length and then the packet to the agent. */
	if (atomicio(vwrite, sock, buf, 4) != 4 ||
	    atomicio(vwrite, sock, (u_char *)sshbuf_ptr(request),
	    sshbuf_len(request)) != sshbuf_len(request))
		return SSH_ERR_AGENT_COMMUNICATION;
	/*
	 * Wait for response from the agent.  First read the length of the
	 * response packet.
	 */
	if (atomicio(read, sock, buf, 4) != 4)
	    return SSH_ERR_AGENT_COMMUNICATION;

	/* Extract the length, and check it for sanity. */
	len = get_u32(buf);
	if (len > MAX_AGENT_REPLY_LEN)
		return SSH_ERR_INVALID_FORMAT;

	/* Read the rest of the response in to the buffer. */
	sshbuf_reset(reply);
	while (len > 0) {
		l = len;
		if (l > sizeof(buf))
			l = sizeof(buf);
		if (atomicio(read, sock, buf, l) != l)
			return SSH_ERR_AGENT_COMMUNICATION;
		if ((r = sshbuf_put(reply, buf, l)) != 0)
			return r;
		len -= l;
	}
	return 0;
}

/*
 * Closes the agent socket if it should be closed (depends on how it was
 * obtained).  The argument must have been returned by
 * ssh_get_authentication_socket().
 */
void
ssh_close_authentication_socket(int sock)
{
	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
		close(sock);
}

/* Lock/unlock agent */
int
ssh_lock_agent(int sock, int lock, const char *password)
{
	int r;
	u_char type = lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK;
	struct sshbuf *msg;

	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = sshbuf_put_u8(msg, type)) != 0 ||
	    (r = sshbuf_put_cstring(msg, password)) != 0)
		goto out;
	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
		goto out;
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	r = decode_reply(type);
 out:
	sshbuf_free(msg);
	return r;
}

#ifdef WITH_SSH1
static int
deserialise_identity1(struct sshbuf *ids, struct sshkey **keyp, char **commentp)
{
	struct sshkey *key;
	int r, keybits;
	u_int32_t bits;
	char *comment = NULL;

	if ((key = sshkey_new(KEY_RSA1)) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = sshbuf_get_u32(ids, &bits)) != 0 ||
	    (r = sshbuf_get_bignum1(ids, key->rsa->e)) != 0 ||
	    (r = sshbuf_get_bignum1(ids, key->rsa->n)) != 0 ||
	    (r = sshbuf_get_cstring(ids, &comment, NULL)) != 0)
		goto out;
	keybits = BN_num_bits(key->rsa->n);
	/* XXX previously we just warned here. I think we should be strict */
	if (keybits < 0 || bits != (u_int)keybits) {
		r = SSH_ERR_KEY_BITS_MISMATCH;
		goto out;
	}
	if (keyp != NULL) {
		*keyp = key;
		key = NULL;
	}
	if (commentp != NULL) {
		*commentp = comment;
		comment = NULL;
	}
	r = 0;
 out:
	sshkey_free(key);
	free(comment);
	return r;
}
#endif

static int
deserialise_identity2(struct sshbuf *ids, struct sshkey **keyp, char **commentp)
{
	int r;
	char *comment = NULL;
	const u_char *blob;
	size_t blen;

	if ((r = sshbuf_get_string_direct(ids, &blob, &blen)) != 0 ||
	    (r = sshbuf_get_cstring(ids, &comment, NULL)) != 0)
		goto out;
	if ((r = sshkey_from_blob(blob, blen, keyp)) != 0)
		goto out;
	if (commentp != NULL) {
		*commentp = comment;
		comment = NULL;
	}
	r = 0;
 out:
	free(comment);
	return r;
}

/*
 * Fetch list of identities held by the agent.
 */
int
ssh_fetch_identitylist(int sock, int version, struct ssh_identitylist **idlp)
{
	u_char type, code1 = 0, code2 = 0;
	u_int32_t num, i;
	struct sshbuf *msg;
	struct ssh_identitylist *idl = NULL;
	int r;

	/* Determine request and expected response types */
	switch (version) {
	case 1:
		code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
		code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
		break;
	case 2:
		code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
		code2 = SSH2_AGENT_IDENTITIES_ANSWER;
		break;
	default:
		return SSH_ERR_INVALID_ARGUMENT;
	}

	/*
	 * Send a message to the agent requesting for a list of the
	 * identities it can represent.
	 */
	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = sshbuf_put_u8(msg, code1)) != 0)
		goto out;

	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
		goto out;

	/* Get message type, and verify that we got a proper answer. */
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	if (agent_failed(type)) {
		r = SSH_ERR_AGENT_FAILURE;
		goto out;
	} else if (type != code2) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}

	/* Get the number of entries in the response and check it for sanity. */
	if ((r = sshbuf_get_u32(msg, &num)) != 0)
		goto out;
	if (num > MAX_AGENT_IDENTITIES) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}
	if (num == 0) {
		r = SSH_ERR_AGENT_NO_IDENTITIES;
		goto out;
	}

	/* Deserialise the response into a list of keys/comments */
	if ((idl = calloc(1, sizeof(*idl))) == NULL ||
	    (idl->keys = calloc(num, sizeof(*idl->keys))) == NULL ||
	    (idl->comments = calloc(num, sizeof(*idl->comments))) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	for (i = 0; i < num;) {
		switch (version) {
		case 1:
#ifdef WITH_SSH1
			if ((r = deserialise_identity1(msg,
			    &(idl->keys[i]), &(idl->comments[i]))) != 0)
				goto out;
#endif
			break;
		case 2:
			if ((r = deserialise_identity2(msg,
			    &(idl->keys[i]), &(idl->comments[i]))) != 0) {
				if (r == SSH_ERR_KEY_TYPE_UNKNOWN) {
					/* Gracefully skip unknown key types */
					num--;
					continue;
				} else
					goto out;
			}
			break;
		}
		i++;
	}
	idl->nkeys = num;
	*idlp = idl;
	idl = NULL;
	r = 0;
 out:
	sshbuf_free(msg);
	if (idl != NULL)
		ssh_free_identitylist(idl);
	return r;
}

void
ssh_free_identitylist(struct ssh_identitylist *idl)
{
	size_t i;

	if (idl == NULL)
		return;
	for (i = 0; i < idl->nkeys; i++) {
		if (idl->keys != NULL)
			sshkey_free(idl->keys[i]);
		if (idl->comments != NULL)
			free(idl->comments[i]);
	}
	free(idl);
}

/*
 * Sends a challenge (typically from a server via ssh(1)) to the agent,
 * and waits for a response from the agent.
 * Returns true (non-zero) if the agent gave the correct answer, zero
 * otherwise.
 */

#ifdef WITH_SSH1
int
ssh_decrypt_challenge(int sock, struct sshkey* key, BIGNUM *challenge,
    u_char session_id[16], u_char response[16])
{
	struct sshbuf *msg;
	int r;
	u_char type;

	if (key->type != KEY_RSA1)
		return SSH_ERR_INVALID_ARGUMENT;
	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = sshbuf_put_u8(msg, SSH_AGENTC_RSA_CHALLENGE)) != 0 ||
	    (r = sshbuf_put_u32(msg, BN_num_bits(key->rsa->n))) != 0 ||
	    (r = sshbuf_put_bignum1(msg, key->rsa->e)) != 0 ||
	    (r = sshbuf_put_bignum1(msg, key->rsa->n)) != 0 ||
	    (r = sshbuf_put_bignum1(msg, challenge)) != 0 ||
	    (r = sshbuf_put(msg, session_id, 16)) != 0 ||
	    (r = sshbuf_put_u32(msg, 1)) != 0) /* Response type for proto 1.1 */
		goto out;
	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
		goto out;
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	if (agent_failed(type)) {
		r = SSH_ERR_AGENT_FAILURE;
		goto out;
	} else if (type != SSH_AGENT_RSA_RESPONSE) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}
	if ((r = sshbuf_get(msg, response, 16)) != 0)
		goto out;
	r = 0;
 out:
	sshbuf_free(msg);
	return r;
}
#endif

/* ask agent to sign data, returns err.h code on error, 0 on success */
int
ssh_agent_sign(int sock, struct sshkey *key,
    u_char **sigp, size_t *lenp,
    const u_char *data, size_t datalen, u_int compat)
{
	struct sshbuf *msg;
	u_char *blob = NULL, type;
	size_t blen = 0, len = 0;
	u_int flags = 0;
	int r = SSH_ERR_INTERNAL_ERROR;

	if (sigp != NULL)
		*sigp = NULL;
	if (lenp != NULL)
		*lenp = 0;

	if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
		return SSH_ERR_INVALID_ARGUMENT;
	if (compat & SSH_BUG_SIGBLOB)
		flags |= SSH_AGENT_OLD_SIGNATURE;
	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = sshkey_to_blob(key, &blob, &blen)) != 0)
		goto out;
	if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
	    (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
	    (r = sshbuf_put_string(msg, data, datalen)) != 0 ||
	    (r = sshbuf_put_u32(msg, flags)) != 0)
		goto out;
	if ((r = ssh_request_reply(sock, msg, msg) != 0))
		goto out;
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	if (agent_failed(type)) {
		r = SSH_ERR_AGENT_FAILURE;
		goto out;
	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}
	if ((r = sshbuf_get_string(msg, sigp, &len)) != 0)
		goto out;
	*lenp = len;
	r = 0;
 out:
	if (blob != NULL) {
		explicit_bzero(blob, blen);
		free(blob);
	}
	sshbuf_free(msg);
	return r;
}

/* Encode key for a message to the agent. */

#ifdef WITH_SSH1
static int
ssh_encode_identity_rsa1(struct sshbuf *b, RSA *key, const char *comment)
{
	int r;

	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	if ((r = sshbuf_put_u32(b, BN_num_bits(key->n))) != 0 ||
	    (r = sshbuf_put_bignum1(b, key->n)) != 0 ||
	    (r = sshbuf_put_bignum1(b, key->e)) != 0 ||
	    (r = sshbuf_put_bignum1(b, key->d)) != 0 ||
	    (r = sshbuf_put_bignum1(b, key->iqmp)) != 0 ||
	    (r = sshbuf_put_bignum1(b, key->q)) != 0 ||
	    (r = sshbuf_put_bignum1(b, key->p)) != 0 ||
	    (r = sshbuf_put_cstring(b, comment)) != 0)
		return r;
	return 0;
}
#endif

static int
ssh_encode_identity_ssh2(struct sshbuf *b, struct sshkey *key,
    const char *comment)
{
	int r;

	if ((r = sshkey_private_serialize(key, b)) != 0 ||
	    (r = sshbuf_put_cstring(b, comment)) != 0)
		return r;
	return 0;
}

static int
encode_constraints(struct sshbuf *m, u_int life, u_int confirm)
{
	int r;

	if (life != 0) {
		if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_LIFETIME)) != 0 ||
		    (r = sshbuf_put_u32(m, life)) != 0)
			goto out;
	}
	if (confirm != 0) {
		if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_CONFIRM)) != 0)
			goto out;
	}
	r = 0;
 out:
	return r;
}

/*
 * Adds an identity to the authentication server.
 * This call is intended only for use by ssh-add(1) and like applications.
 */
int
ssh_add_identity_constrained(int sock, struct sshkey *key, const char *comment,
    u_int life, u_int confirm)
{
	struct sshbuf *msg;
	int r, constrained = (life || confirm);
	u_char type;

	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;

	switch (key->type) {
#ifdef WITH_SSH1
	case KEY_RSA1:
		type = constrained ?
		    SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
		    SSH_AGENTC_ADD_RSA_IDENTITY;
		if ((r = sshbuf_put_u8(msg, type)) != 0 ||
		    (r = ssh_encode_identity_rsa1(msg, key->rsa, comment)) != 0)
			goto out;
		break;
#endif
#ifdef WITH_OPENSSL
	case KEY_RSA:
	case KEY_RSA_CERT:
	case KEY_RSA_CERT_V00:
	case KEY_DSA:
	case KEY_DSA_CERT:
	case KEY_DSA_CERT_V00:
	case KEY_ECDSA:
	case KEY_ECDSA_CERT:
#endif
	case KEY_ED25519:
	case KEY_ED25519_CERT:
		type = constrained ?
		    SSH2_AGENTC_ADD_ID_CONSTRAINED :
		    SSH2_AGENTC_ADD_IDENTITY;
		if ((r = sshbuf_put_u8(msg, type)) != 0 ||
		    (r = ssh_encode_identity_ssh2(msg, key, comment)) != 0)
			goto out;
		break;
	default:
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	if (constrained &&
	    (r = encode_constraints(msg, life, confirm)) != 0)
		goto out;
	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
		goto out;
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	r = decode_reply(type);
 out:
	sshbuf_free(msg);
	return r;
}

/*
 * Removes an identity from the authentication server.
 * This call is intended only for use by ssh-add(1) and like applications.
 */
int
ssh_remove_identity(int sock, struct sshkey *key)
{
	struct sshbuf *msg;
	int r;
	u_char type, *blob = NULL;
	size_t blen;

	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;

#ifdef WITH_SSH1
	if (key->type == KEY_RSA1) {
		if ((r = sshbuf_put_u8(msg,
		    SSH_AGENTC_REMOVE_RSA_IDENTITY)) != 0 ||
		    (r = sshbuf_put_u32(msg, BN_num_bits(key->rsa->n))) != 0 ||
		    (r = sshbuf_put_bignum1(msg, key->rsa->e)) != 0 ||
		    (r = sshbuf_put_bignum1(msg, key->rsa->n)) != 0)
			goto out;
	} else
#endif
	if (key->type != KEY_UNSPEC) {
		if ((r = sshkey_to_blob(key, &blob, &blen)) != 0)
			goto out;
		if ((r = sshbuf_put_u8(msg,
		    SSH2_AGENTC_REMOVE_IDENTITY)) != 0 ||
		    (r = sshbuf_put_string(msg, blob, blen)) != 0)
			goto out;
	} else {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
		goto out;
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	r = decode_reply(type);
 out:
	if (blob != NULL) {
		explicit_bzero(blob, blen);
		free(blob);
	}
	sshbuf_free(msg);
	return r;
}

/*
 * Add/remove an token-based identity from the authentication server.
 * This call is intended only for use by ssh-add(1) and like applications.
 */
int
ssh_update_card(int sock, int add, const char *reader_id, const char *pin,
    u_int life, u_int confirm)
{
	struct sshbuf *msg;
	int r, constrained = (life || confirm);
	u_char type;

	if (add) {
		type = constrained ?
		    SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED :
		    SSH_AGENTC_ADD_SMARTCARD_KEY;
	} else
		type = SSH_AGENTC_REMOVE_SMARTCARD_KEY;

	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = sshbuf_put_u8(msg, type)) != 0 ||
	    (r = sshbuf_put_cstring(msg, reader_id)) != 0 ||
	    (r = sshbuf_put_cstring(msg, pin)) != 0)
		goto out;
	if (constrained &&
	    (r = encode_constraints(msg, life, confirm)) != 0)
		goto out;
	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
		goto out;
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	r = decode_reply(type);
 out:
	sshbuf_free(msg);
	return r;
}

/*
 * Removes all identities from the agent.
 * This call is intended only for use by ssh-add(1) and like applications.
 */
int
ssh_remove_all_identities(int sock, int version)
{
	struct sshbuf *msg;
	u_char type = (version == 1) ?
	    SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
	    SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
	int r;

	if ((msg = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = sshbuf_put_u8(msg, type)) != 0)
		goto out;
	if ((r = ssh_request_reply(sock, msg, msg)) != 0)
		goto out;
	if ((r = sshbuf_get_u8(msg, &type)) != 0)
		goto out;
	r = decode_reply(type);
 out:
	sshbuf_free(msg);
	return r;
}