1 /*        $NetBSD: authfd.c,v 1.27 2023/12/20 17:15:20 christos Exp $ */
2 /* $OpenBSD: authfd.c,v 1.134 2023/12/18 14:46:56 djm Exp $ */
3 
4 /*
5  * Author: Tatu Ylonen <ylo@cs.hut.fi>
6  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7  *                    All rights reserved
8  * Functions for connecting the local authentication agent.
9  *
10  * As far as I am concerned, the code I have written for this software
11  * can be used freely for any purpose.  Any derived versions of this
12  * software must be clearly marked as such, and if the derived work is
13  * incompatible with the protocol description in the RFC file, it must be
14  * called by a name other than "ssh" or "Secure Shell".
15  *
16  * SSH2 implementation,
17  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
18  *
19  * Redistribution and use in source and binary forms, with or without
20  * modification, are permitted provided that the following conditions
21  * are met:
22  * 1. Redistributions of source code must retain the above copyright
23  *    notice, this list of conditions and the following disclaimer.
24  * 2. Redistributions in binary form must reproduce the above copyright
25  *    notice, this list of conditions and the following disclaimer in the
26  *    documentation and/or other materials provided with the distribution.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 #include "includes.h"
41 __RCSID("$NetBSD: authfd.c,v 1.27 2023/12/20 17:15:20 christos Exp $");
42 #include <sys/types.h>
43 #include <sys/un.h>
44 #include <sys/socket.h>
45 
46 #include <fcntl.h>
47 #include <stdlib.h>
48 #include <signal.h>
49 #include <string.h>
50 #include <stdarg.h>
51 #include <unistd.h>
52 #include <errno.h>
53 
54 #include "xmalloc.h"
55 #include "ssh.h"
56 #include "sshbuf.h"
57 #include "sshkey.h"
58 #include "authfd.h"
59 #include "cipher.h"
60 #include "log.h"
61 #include "atomicio.h"
62 #include "misc.h"
63 #include "ssherr.h"
64 
65 #define MAX_AGENT_IDENTITIES  2048                /* Max keys in agent reply */
66 #define MAX_AGENT_REPLY_LEN   (256 * 1024)        /* Max bytes in agent reply */
67 
68 /* macro to check for "agent failure" message */
69 #define agent_failed(x) \
70     ((x == SSH_AGENT_FAILURE) || \
71     (x == SSH_COM_AGENT2_FAILURE) || \
72     (x == SSH2_AGENT_FAILURE))
73 
74 /* Convert success/failure response from agent to a err.h status */
75 static int
decode_reply(u_char type)76 decode_reply(u_char type)
77 {
78           if (agent_failed(type))
79                     return SSH_ERR_AGENT_FAILURE;
80           else if (type == SSH_AGENT_SUCCESS)
81                     return 0;
82           else
83                     return SSH_ERR_INVALID_FORMAT;
84 }
85 
86 /*
87  * Opens an authentication socket at the provided path and stores the file
88  * descriptor in fdp. Returns 0 on success and an error on failure.
89  */
90 int
ssh_get_authentication_socket_path(const char * authsocket,int * fdp)91 ssh_get_authentication_socket_path(const char *authsocket, int *fdp)
92 {
93           int sock, oerrno;
94           struct sockaddr_un sunaddr;
95 
96           debug3_f("path '%s'", authsocket);
97           memset(&sunaddr, 0, sizeof(sunaddr));
98           sunaddr.sun_family = AF_UNIX;
99           strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
100 
101           if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
102                     return SSH_ERR_SYSTEM_ERROR;
103 
104           /* close on exec */
105           if (fcntl(sock, F_SETFD, FD_CLOEXEC) == -1 ||
106               connect(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
107                     oerrno = errno;
108                     close(sock);
109                     errno = oerrno;
110                     return SSH_ERR_SYSTEM_ERROR;
111           }
112           if (fdp != NULL)
113                     *fdp = sock;
114           else
115                     close(sock);
116           return 0;
117 }
118 
119 /*
120  * Opens the default authentication socket and stores the file descriptor in
121  * fdp. Returns 0 on success and an error on failure.
122  */
123 int
ssh_get_authentication_socket(int * fdp)124 ssh_get_authentication_socket(int *fdp)
125 {
126           const char *authsocket;
127 
128           if (fdp != NULL)
129                     *fdp = -1;
130 
131           authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
132           if (authsocket == NULL || *authsocket == '\0')
133                     return SSH_ERR_AGENT_NOT_PRESENT;
134 
135           return ssh_get_authentication_socket_path(authsocket, fdp);
136 }
137 
138 /* Communicate with agent: send request and read reply */
139 static int
ssh_request_reply(int sock,struct sshbuf * request,struct sshbuf * reply)140 ssh_request_reply(int sock, struct sshbuf *request, struct sshbuf *reply)
141 {
142           int r;
143           size_t l, len;
144           char buf[1024];
145 
146           /* Get the length of the message, and format it in the buffer. */
147           len = sshbuf_len(request);
148           POKE_U32(buf, len);
149 
150           /* Send the length and then the packet to the agent. */
151           if (atomicio(vwrite, sock, buf, 4) != 4 ||
152               atomicio(vwrite, sock, sshbuf_mutable_ptr(request),
153               sshbuf_len(request)) != sshbuf_len(request))
154                     return SSH_ERR_AGENT_COMMUNICATION;
155           /*
156            * Wait for response from the agent.  First read the length of the
157            * response packet.
158            */
159           if (atomicio(read, sock, buf, 4) != 4)
160               return SSH_ERR_AGENT_COMMUNICATION;
161 
162           /* Extract the length, and check it for sanity. */
163           len = PEEK_U32(buf);
164           if (len > MAX_AGENT_REPLY_LEN)
165                     return SSH_ERR_INVALID_FORMAT;
166 
167           /* Read the rest of the response in to the buffer. */
168           sshbuf_reset(reply);
169           while (len > 0) {
170                     l = len;
171                     if (l > sizeof(buf))
172                               l = sizeof(buf);
173                     if (atomicio(read, sock, buf, l) != l)
174                               return SSH_ERR_AGENT_COMMUNICATION;
175                     if ((r = sshbuf_put(reply, buf, l)) != 0)
176                               return r;
177                     len -= l;
178           }
179           return 0;
180 }
181 
182 /* Communicate with agent: sent request, read and decode status reply */
183 static int
ssh_request_reply_decode(int sock,struct sshbuf * request)184 ssh_request_reply_decode(int sock, struct sshbuf *request)
185 {
186           struct sshbuf *reply;
187           int r;
188           u_char type;
189 
190           if ((reply = sshbuf_new()) == NULL)
191                     return SSH_ERR_ALLOC_FAIL;
192           if ((r = ssh_request_reply(sock, request, reply)) != 0 ||
193               (r = sshbuf_get_u8(reply, &type)) != 0 ||
194               (r = decode_reply(type)) != 0)
195                     goto out;
196           /* success */
197           r = 0;
198  out:
199           sshbuf_free(reply);
200           return r;
201 }
202 
203 /*
204  * Closes the agent socket if it should be closed (depends on how it was
205  * obtained).  The argument must have been returned by
206  * ssh_get_authentication_socket().
207  */
208 void
ssh_close_authentication_socket(int sock)209 ssh_close_authentication_socket(int sock)
210 {
211           if (getenv(SSH_AUTHSOCKET_ENV_NAME))
212                     close(sock);
213 }
214 
215 /* Lock/unlock agent */
216 int
ssh_lock_agent(int sock,int lock,const char * password)217 ssh_lock_agent(int sock, int lock, const char *password)
218 {
219           int r;
220           u_char type = lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK;
221           struct sshbuf *msg;
222 
223           if ((msg = sshbuf_new()) == NULL)
224                     return SSH_ERR_ALLOC_FAIL;
225           if ((r = sshbuf_put_u8(msg, type)) != 0 ||
226               (r = sshbuf_put_cstring(msg, password)) != 0 ||
227               (r = ssh_request_reply_decode(sock, msg)) != 0)
228                     goto out;
229           /* success */
230           r = 0;
231  out:
232           sshbuf_free(msg);
233           return r;
234 }
235 
236 
237 static int
deserialise_identity2(struct sshbuf * ids,struct sshkey ** keyp,char ** commentp)238 deserialise_identity2(struct sshbuf *ids, struct sshkey **keyp, char **commentp)
239 {
240           int r;
241           char *comment = NULL;
242           const u_char *blob;
243           size_t blen;
244 
245           if ((r = sshbuf_get_string_direct(ids, &blob, &blen)) != 0 ||
246               (r = sshbuf_get_cstring(ids, &comment, NULL)) != 0)
247                     goto out;
248           if ((r = sshkey_from_blob(blob, blen, keyp)) != 0)
249                     goto out;
250           if (commentp != NULL) {
251                     *commentp = comment;
252                     comment = NULL;
253           }
254           r = 0;
255  out:
256           free(comment);
257           return r;
258 }
259 
260 /*
261  * Fetch list of identities held by the agent.
262  */
263 int
ssh_fetch_identitylist(int sock,struct ssh_identitylist ** idlp)264 ssh_fetch_identitylist(int sock, struct ssh_identitylist **idlp)
265 {
266           u_char type;
267           u_int32_t num, i;
268           struct sshbuf *msg;
269           struct ssh_identitylist *idl = NULL;
270           int r;
271 
272           /*
273            * Send a message to the agent requesting for a list of the
274            * identities it can represent.
275            */
276           if ((msg = sshbuf_new()) == NULL)
277                     return SSH_ERR_ALLOC_FAIL;
278           if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_REQUEST_IDENTITIES)) != 0)
279                     goto out;
280 
281           if ((r = ssh_request_reply(sock, msg, msg)) != 0)
282                     goto out;
283 
284           /* Get message type, and verify that we got a proper answer. */
285           if ((r = sshbuf_get_u8(msg, &type)) != 0)
286                     goto out;
287           if (agent_failed(type)) {
288                     r = SSH_ERR_AGENT_FAILURE;
289                     goto out;
290           } else if (type != SSH2_AGENT_IDENTITIES_ANSWER) {
291                     r = SSH_ERR_INVALID_FORMAT;
292                     goto out;
293           }
294 
295           /* Get the number of entries in the response and check it for sanity. */
296           if ((r = sshbuf_get_u32(msg, &num)) != 0)
297                     goto out;
298           if (num > MAX_AGENT_IDENTITIES) {
299                     r = SSH_ERR_INVALID_FORMAT;
300                     goto out;
301           }
302           if (num == 0) {
303                     r = SSH_ERR_AGENT_NO_IDENTITIES;
304                     goto out;
305           }
306 
307           /* Deserialise the response into a list of keys/comments */
308           if ((idl = calloc(1, sizeof(*idl))) == NULL ||
309               (idl->keys = calloc(num, sizeof(*idl->keys))) == NULL ||
310               (idl->comments = calloc(num, sizeof(*idl->comments))) == NULL) {
311                     r = SSH_ERR_ALLOC_FAIL;
312                     goto out;
313           }
314           for (i = 0; i < num;) {
315                     if ((r = deserialise_identity2(msg, &(idl->keys[i]),
316                         &(idl->comments[i]))) != 0) {
317                               if (r == SSH_ERR_KEY_TYPE_UNKNOWN) {
318                                         /* Gracefully skip unknown key types */
319                                         num--;
320                                         continue;
321                               } else
322                                         goto out;
323                     }
324                     i++;
325           }
326           idl->nkeys = num;
327           *idlp = idl;
328           idl = NULL;
329           r = 0;
330  out:
331           sshbuf_free(msg);
332           if (idl != NULL)
333                     ssh_free_identitylist(idl);
334           return r;
335 }
336 
337 void
ssh_free_identitylist(struct ssh_identitylist * idl)338 ssh_free_identitylist(struct ssh_identitylist *idl)
339 {
340           size_t i;
341 
342           if (idl == NULL)
343                     return;
344           for (i = 0; i < idl->nkeys; i++) {
345                     if (idl->keys != NULL)
346                               sshkey_free(idl->keys[i]);
347                     if (idl->comments != NULL)
348                               free(idl->comments[i]);
349           }
350           free(idl->keys);
351           free(idl->comments);
352           free(idl);
353 }
354 
355 /*
356  * Check if the ssh agent has a given key.
357  * Returns 0 if found, or a negative SSH_ERR_* error code on failure.
358  */
359 int
ssh_agent_has_key(int sock,const struct sshkey * key)360 ssh_agent_has_key(int sock, const struct sshkey *key)
361 {
362           int r, ret = SSH_ERR_KEY_NOT_FOUND;
363           size_t i;
364           struct ssh_identitylist *idlist = NULL;
365 
366           if ((r = ssh_fetch_identitylist(sock, &idlist)) != 0) {
367                     return r;
368           }
369 
370           for (i = 0; i < idlist->nkeys; i++) {
371                     if (sshkey_equal_public(idlist->keys[i], key)) {
372                               ret = 0;
373                               break;
374                     }
375           }
376 
377           ssh_free_identitylist(idlist);
378           return ret;
379 }
380 
381 /*
382  * Sends a challenge (typically from a server via ssh(1)) to the agent,
383  * and waits for a response from the agent.
384  * Returns true (non-zero) if the agent gave the correct answer, zero
385  * otherwise.
386  */
387 
388 
389 /* encode signature algorithm in flag bits, so we can keep the msg format */
390 static u_int
agent_encode_alg(const struct sshkey * key,const char * alg)391 agent_encode_alg(const struct sshkey *key, const char *alg)
392 {
393           if (alg != NULL && sshkey_type_plain(key->type) == KEY_RSA) {
394                     if (strcmp(alg, "rsa-sha2-256") == 0 ||
395                         strcmp(alg, "rsa-sha2-256-cert-v01@openssh.com") == 0)
396                               return SSH_AGENT_RSA_SHA2_256;
397                     if (strcmp(alg, "rsa-sha2-512") == 0 ||
398                         strcmp(alg, "rsa-sha2-512-cert-v01@openssh.com") == 0)
399                               return SSH_AGENT_RSA_SHA2_512;
400           }
401           return 0;
402 }
403 
404 /* ask agent to sign data, returns err.h code on error, 0 on success */
405 int
ssh_agent_sign(int sock,const struct sshkey * key,u_char ** sigp,size_t * lenp,const u_char * data,size_t datalen,const char * alg,u_int compat)406 ssh_agent_sign(int sock, const struct sshkey *key,
407     u_char **sigp, size_t *lenp,
408     const u_char *data, size_t datalen, const char *alg, u_int compat)
409 {
410           struct sshbuf *msg;
411           u_char *sig = NULL, type = 0;
412           size_t len = 0;
413           u_int flags = 0;
414           int r = SSH_ERR_INTERNAL_ERROR;
415 
416           *sigp = NULL;
417           *lenp = 0;
418 
419           if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
420                     return SSH_ERR_INVALID_ARGUMENT;
421           if ((msg = sshbuf_new()) == NULL)
422                     return SSH_ERR_ALLOC_FAIL;
423           flags |= agent_encode_alg(key, alg);
424           if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
425               (r = sshkey_puts(key, msg)) != 0 ||
426               (r = sshbuf_put_string(msg, data, datalen)) != 0 ||
427               (r = sshbuf_put_u32(msg, flags)) != 0)
428                     goto out;
429           if ((r = ssh_request_reply(sock, msg, msg)) != 0)
430                     goto out;
431           if ((r = sshbuf_get_u8(msg, &type)) != 0)
432                     goto out;
433           if (agent_failed(type)) {
434                     r = SSH_ERR_AGENT_FAILURE;
435                     goto out;
436           } else if (type != SSH2_AGENT_SIGN_RESPONSE) {
437                     r = SSH_ERR_INVALID_FORMAT;
438                     goto out;
439           }
440           if ((r = sshbuf_get_string(msg, &sig, &len)) != 0)
441                     goto out;
442           /* Check what we actually got back from the agent. */
443           if ((r = sshkey_check_sigtype(sig, len, alg)) != 0)
444                     goto out;
445           /* success */
446           *sigp = sig;
447           *lenp = len;
448           sig = NULL;
449           len = 0;
450           r = 0;
451  out:
452           freezero(sig, len);
453           sshbuf_free(msg);
454           return r;
455 }
456 
457 /* Encode key for a message to the agent. */
458 
459 static int
encode_dest_constraint_hop(struct sshbuf * m,const struct dest_constraint_hop * dch)460 encode_dest_constraint_hop(struct sshbuf *m,
461     const struct dest_constraint_hop *dch)
462 {
463           struct sshbuf *b;
464           u_int i;
465           int r;
466 
467           if ((b = sshbuf_new()) == NULL)
468                     return SSH_ERR_ALLOC_FAIL;
469           if ((r = sshbuf_put_cstring(b, dch->user)) != 0 ||
470               (r = sshbuf_put_cstring(b, dch->hostname)) != 0 ||
471               (r = sshbuf_put_string(b, NULL, 0)) != 0) /* reserved */
472                     goto out;
473           for (i = 0; i < dch->nkeys; i++) {
474                     if ((r = sshkey_puts(dch->keys[i], b)) != 0 ||
475                         (r = sshbuf_put_u8(b, dch->key_is_ca[i] != 0)) != 0)
476                               goto out;
477           }
478           if ((r = sshbuf_put_stringb(m, b)) != 0)
479                     goto out;
480           /* success */
481           r = 0;
482  out:
483           sshbuf_free(b);
484           return r;
485 }
486 
487 static int
encode_dest_constraint(struct sshbuf * m,const struct dest_constraint * dc)488 encode_dest_constraint(struct sshbuf *m, const struct dest_constraint *dc)
489 {
490           struct sshbuf *b;
491           int r;
492 
493           if ((b = sshbuf_new()) == NULL)
494                     return SSH_ERR_ALLOC_FAIL;
495           if ((r = encode_dest_constraint_hop(b, &dc->from)) != 0 ||
496               (r = encode_dest_constraint_hop(b, &dc->to)) != 0 ||
497               (r = sshbuf_put_string(b, NULL, 0)) != 0) /* reserved */
498                     goto out;
499           if ((r = sshbuf_put_stringb(m, b)) != 0)
500                     goto out;
501           /* success */
502           r = 0;
503  out:
504           sshbuf_free(b);
505           return r;
506 }
507 
508 static int
encode_constraints(struct sshbuf * m,u_int life,u_int confirm,u_int maxsign,const char * provider,struct dest_constraint ** dest_constraints,size_t ndest_constraints,int cert_only,struct sshkey ** certs,size_t ncerts)509 encode_constraints(struct sshbuf *m, u_int life, u_int confirm,
510     u_int maxsign, const char *provider,
511     struct dest_constraint **dest_constraints, size_t ndest_constraints,
512     int cert_only, struct sshkey **certs, size_t ncerts)
513 {
514           int r;
515           struct sshbuf *b = NULL;
516           size_t i;
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           if (maxsign != 0) {
528                     if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_MAXSIGN)) != 0 ||
529                         (r = sshbuf_put_u32(m, maxsign)) != 0)
530                               goto out;
531           }
532           if (provider != NULL) {
533                     if ((r = sshbuf_put_u8(m,
534                         SSH_AGENT_CONSTRAIN_EXTENSION)) != 0 ||
535                         (r = sshbuf_put_cstring(m,
536                         "sk-provider@openssh.com")) != 0 ||
537                         (r = sshbuf_put_cstring(m, provider)) != 0)
538                               goto out;
539           }
540           if (dest_constraints != NULL && ndest_constraints > 0) {
541                     if ((b = sshbuf_new()) == NULL) {
542                               r = SSH_ERR_ALLOC_FAIL;
543                               goto out;
544                     }
545                     for (i = 0; i < ndest_constraints; i++) {
546                               if ((r = encode_dest_constraint(b,
547                                   dest_constraints[i])) != 0)
548                                         goto out;
549                     }
550                     if ((r = sshbuf_put_u8(m,
551                         SSH_AGENT_CONSTRAIN_EXTENSION)) != 0 ||
552                         (r = sshbuf_put_cstring(m,
553                         "restrict-destination-v00@openssh.com")) != 0 ||
554                         (r = sshbuf_put_stringb(m, b)) != 0)
555                               goto out;
556                     sshbuf_free(b);
557                     b = NULL;
558           }
559           if (ncerts != 0) {
560                     if ((b = sshbuf_new()) == NULL) {
561                               r = SSH_ERR_ALLOC_FAIL;
562                               goto out;
563                     }
564                     for (i = 0; i < ncerts; i++) {
565                               if ((r = sshkey_puts(certs[i], b)) != 0)
566                                         goto out;
567                     }
568                     if ((r = sshbuf_put_u8(m,
569                         SSH_AGENT_CONSTRAIN_EXTENSION)) != 0 ||
570                         (r = sshbuf_put_cstring(m,
571                         "associated-certs-v00@openssh.com")) != 0 ||
572                         (r = sshbuf_put_u8(m, cert_only != 0)) != 0 ||
573                         (r = sshbuf_put_stringb(m, b)) != 0)
574                               goto out;
575                     sshbuf_free(b);
576                     b = NULL;
577           }
578           r = 0;
579  out:
580           sshbuf_free(b);
581           return r;
582 }
583 
584 /*
585  * Adds an identity to the authentication server.
586  * This call is intended only for use by ssh-add(1) and like applications.
587  */
588 int
ssh_add_identity_constrained(int sock,struct sshkey * key,const char * comment,u_int life,u_int confirm,u_int maxsign,const char * provider,struct dest_constraint ** dest_constraints,size_t ndest_constraints)589 ssh_add_identity_constrained(int sock, struct sshkey *key,
590     const char *comment, u_int life, u_int confirm, u_int maxsign,
591     const char *provider, struct dest_constraint **dest_constraints,
592     size_t ndest_constraints)
593 {
594           struct sshbuf *msg;
595           int r, constrained = (life || confirm || maxsign ||
596               provider || dest_constraints);
597           u_char type;
598 
599           if ((msg = sshbuf_new()) == NULL)
600                     return SSH_ERR_ALLOC_FAIL;
601 
602           switch (key->type) {
603 #ifdef WITH_OPENSSL
604           case KEY_RSA:
605           case KEY_RSA_CERT:
606           case KEY_DSA:
607           case KEY_DSA_CERT:
608           case KEY_ECDSA:
609           case KEY_ECDSA_CERT:
610           case KEY_ECDSA_SK:
611           case KEY_ECDSA_SK_CERT:
612 #endif
613           case KEY_ED25519:
614           case KEY_ED25519_CERT:
615           case KEY_ED25519_SK:
616           case KEY_ED25519_SK_CERT:
617           case KEY_XMSS:
618           case KEY_XMSS_CERT:
619                     type = constrained ?
620                         SSH2_AGENTC_ADD_ID_CONSTRAINED :
621                         SSH2_AGENTC_ADD_IDENTITY;
622                     if ((r = sshbuf_put_u8(msg, type)) != 0 ||
623                         (r = sshkey_private_serialize_maxsign(key, msg, maxsign,
624                         0)) != 0 ||
625                         (r = sshbuf_put_cstring(msg, comment)) != 0)
626                               goto out;
627                     break;
628           default:
629                     r = SSH_ERR_INVALID_ARGUMENT;
630                     goto out;
631           }
632           if (constrained &&
633               (r = encode_constraints(msg, life, confirm, maxsign,
634               provider, dest_constraints, ndest_constraints, 0, NULL, 0)) != 0)
635                     goto out;
636           if ((r = ssh_request_reply_decode(sock, msg)) != 0)
637                     goto out;
638           /* success */
639           r = 0;
640  out:
641           sshbuf_free(msg);
642           return r;
643 }
644 
645 /*
646  * Removes an identity from the authentication server.
647  * This call is intended only for use by ssh-add(1) and like applications.
648  */
649 int
ssh_remove_identity(int sock,const struct sshkey * key)650 ssh_remove_identity(int sock, const struct sshkey *key)
651 {
652           struct sshbuf *msg;
653           int r;
654           u_char *blob = NULL;
655           size_t blen;
656 
657           if ((msg = sshbuf_new()) == NULL)
658                     return SSH_ERR_ALLOC_FAIL;
659 
660           if (key->type != KEY_UNSPEC) {
661                     if ((r = sshkey_to_blob(key, &blob, &blen)) != 0)
662                               goto out;
663                     if ((r = sshbuf_put_u8(msg,
664                         SSH2_AGENTC_REMOVE_IDENTITY)) != 0 ||
665                         (r = sshbuf_put_string(msg, blob, blen)) != 0)
666                               goto out;
667           } else {
668                     r = SSH_ERR_INVALID_ARGUMENT;
669                     goto out;
670           }
671           if ((r = ssh_request_reply_decode(sock, msg)) != 0)
672                     goto out;
673           /* success */
674           r = 0;
675  out:
676           if (blob != NULL)
677                     freezero(blob, blen);
678           sshbuf_free(msg);
679           return r;
680 }
681 
682 /*
683  * Add/remove an token-based identity from the authentication server.
684  * This call is intended only for use by ssh-add(1) and like applications.
685  */
686 int
ssh_update_card(int sock,int add,const char * reader_id,const char * pin,u_int life,u_int confirm,struct dest_constraint ** dest_constraints,size_t ndest_constraints,int cert_only,struct sshkey ** certs,size_t ncerts)687 ssh_update_card(int sock, int add, const char *reader_id, const char *pin,
688     u_int life, u_int confirm,
689     struct dest_constraint **dest_constraints, size_t ndest_constraints,
690     int cert_only, struct sshkey **certs, size_t ncerts)
691 {
692           struct sshbuf *msg;
693           int r, constrained = (life || confirm || dest_constraints || certs);
694           u_char type;
695 
696           if (add) {
697                     type = constrained ?
698                         SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED :
699                         SSH_AGENTC_ADD_SMARTCARD_KEY;
700           } else
701                     type = SSH_AGENTC_REMOVE_SMARTCARD_KEY;
702 
703           if ((msg = sshbuf_new()) == NULL)
704                     return SSH_ERR_ALLOC_FAIL;
705           if ((r = sshbuf_put_u8(msg, type)) != 0 ||
706               (r = sshbuf_put_cstring(msg, reader_id)) != 0 ||
707               (r = sshbuf_put_cstring(msg, pin)) != 0)
708                     goto out;
709           if (constrained &&
710               (r = encode_constraints(msg, life, confirm, 0, NULL,
711               dest_constraints, ndest_constraints,
712               cert_only, certs, ncerts)) != 0)
713                     goto out;
714           if ((r = ssh_request_reply_decode(sock, msg)) != 0)
715                     goto out;
716           /* success */
717           r = 0;
718  out:
719           sshbuf_free(msg);
720           return r;
721 }
722 
723 /*
724  * Removes all identities from the agent.
725  * This call is intended only for use by ssh-add(1) and like applications.
726  *
727  * This supports the SSH protocol 1 message to because, when clearing all
728  * keys from an agent, we generally want to clear both protocol v1 and v2
729  * keys.
730  */
731 int
ssh_remove_all_identities(int sock,int version)732 ssh_remove_all_identities(int sock, int version)
733 {
734           struct sshbuf *msg;
735           u_char type = (version == 1) ?
736               SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
737               SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
738           int r;
739 
740           if ((msg = sshbuf_new()) == NULL)
741                     return SSH_ERR_ALLOC_FAIL;
742           if ((r = sshbuf_put_u8(msg, type)) != 0)
743                     goto out;
744           if ((r = ssh_request_reply_decode(sock, msg)) != 0)
745                     goto out;
746           /* success */
747           r = 0;
748  out:
749           sshbuf_free(msg);
750           return r;
751 }
752 
753 /* Binds a session ID to a hostkey via the initial KEX signature. */
754 int
ssh_agent_bind_hostkey(int sock,const struct sshkey * key,const struct sshbuf * session_id,const struct sshbuf * signature,int forwarding)755 ssh_agent_bind_hostkey(int sock, const struct sshkey *key,
756     const struct sshbuf *session_id, const struct sshbuf *signature,
757     int forwarding)
758 {
759           struct sshbuf *msg;
760           int r;
761 
762           if (key == NULL || session_id == NULL || signature == NULL)
763                     return SSH_ERR_INVALID_ARGUMENT;
764           if ((msg = sshbuf_new()) == NULL)
765                     return SSH_ERR_ALLOC_FAIL;
766           if ((r = sshbuf_put_u8(msg, SSH_AGENTC_EXTENSION)) != 0 ||
767               (r = sshbuf_put_cstring(msg, "session-bind@openssh.com")) != 0 ||
768               (r = sshkey_puts(key, msg)) != 0 ||
769               (r = sshbuf_put_stringb(msg, session_id)) != 0 ||
770               (r = sshbuf_put_stringb(msg, signature)) != 0 ||
771               (r = sshbuf_put_u8(msg, forwarding ? 1 : 0)) != 0)
772                     goto out;
773           if ((r = ssh_request_reply_decode(sock, msg)) != 0)
774                     goto out;
775           /* success */
776           r = 0;
777  out:
778           sshbuf_free(msg);
779           return r;
780 }
781