1 /* $OpenBSD: authfd.c,v 1.128 2021/12/19 22:08:48 djm 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 <stdarg.h> 48 #include <unistd.h> 49 #include <errno.h> 50 51 #include "xmalloc.h" 52 #include "ssh.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 /* 85 * Opens an authentication socket at the provided path and stores the file 86 * descriptor in fdp. Returns 0 on success and an error on failure. 87 */ 88 int 89 ssh_get_authentication_socket_path(const char *authsocket, int *fdp) 90 { 91 int sock, oerrno; 92 struct sockaddr_un sunaddr; 93 94 memset(&sunaddr, 0, sizeof(sunaddr)); 95 sunaddr.sun_family = AF_UNIX; 96 strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path)); 97 98 if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 99 return SSH_ERR_SYSTEM_ERROR; 100 101 /* close on exec */ 102 if (fcntl(sock, F_SETFD, FD_CLOEXEC) == -1 || 103 connect(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) { 104 oerrno = errno; 105 close(sock); 106 errno = oerrno; 107 return SSH_ERR_SYSTEM_ERROR; 108 } 109 if (fdp != NULL) 110 *fdp = sock; 111 else 112 close(sock); 113 return 0; 114 } 115 116 /* 117 * Opens the default authentication socket and stores the file descriptor in 118 * fdp. Returns 0 on success and an error on failure. 119 */ 120 int 121 ssh_get_authentication_socket(int *fdp) 122 { 123 const char *authsocket; 124 125 if (fdp != NULL) 126 *fdp = -1; 127 128 authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME); 129 if (authsocket == NULL || *authsocket == '\0') 130 return SSH_ERR_AGENT_NOT_PRESENT; 131 132 return ssh_get_authentication_socket_path(authsocket, fdp); 133 } 134 135 /* Communicate with agent: send request and read reply */ 136 static int 137 ssh_request_reply(int sock, struct sshbuf *request, struct sshbuf *reply) 138 { 139 int r; 140 size_t l, len; 141 char buf[1024]; 142 143 /* Get the length of the message, and format it in the buffer. */ 144 len = sshbuf_len(request); 145 POKE_U32(buf, len); 146 147 /* Send the length and then the packet to the agent. */ 148 if (atomicio(vwrite, sock, buf, 4) != 4 || 149 atomicio(vwrite, sock, sshbuf_mutable_ptr(request), 150 sshbuf_len(request)) != sshbuf_len(request)) 151 return SSH_ERR_AGENT_COMMUNICATION; 152 /* 153 * Wait for response from the agent. First read the length of the 154 * response packet. 155 */ 156 if (atomicio(read, sock, buf, 4) != 4) 157 return SSH_ERR_AGENT_COMMUNICATION; 158 159 /* Extract the length, and check it for sanity. */ 160 len = PEEK_U32(buf); 161 if (len > MAX_AGENT_REPLY_LEN) 162 return SSH_ERR_INVALID_FORMAT; 163 164 /* Read the rest of the response in to the buffer. */ 165 sshbuf_reset(reply); 166 while (len > 0) { 167 l = len; 168 if (l > sizeof(buf)) 169 l = sizeof(buf); 170 if (atomicio(read, sock, buf, l) != l) 171 return SSH_ERR_AGENT_COMMUNICATION; 172 if ((r = sshbuf_put(reply, buf, l)) != 0) 173 return r; 174 len -= l; 175 } 176 return 0; 177 } 178 179 /* Communicate with agent: sent request, read and decode status reply */ 180 static int 181 ssh_request_reply_decode(int sock, struct sshbuf *request) 182 { 183 struct sshbuf *reply; 184 int r; 185 u_char type; 186 187 if ((reply = sshbuf_new()) == NULL) 188 return SSH_ERR_ALLOC_FAIL; 189 if ((r = ssh_request_reply(sock, request, reply)) != 0 || 190 (r = sshbuf_get_u8(reply, &type)) != 0 || 191 (r = decode_reply(type)) != 0) 192 goto out; 193 /* success */ 194 r = 0; 195 out: 196 sshbuf_free(reply); 197 return r; 198 } 199 200 /* 201 * Closes the agent socket if it should be closed (depends on how it was 202 * obtained). The argument must have been returned by 203 * ssh_get_authentication_socket(). 204 */ 205 void 206 ssh_close_authentication_socket(int sock) 207 { 208 if (getenv(SSH_AUTHSOCKET_ENV_NAME)) 209 close(sock); 210 } 211 212 /* Lock/unlock agent */ 213 int 214 ssh_lock_agent(int sock, int lock, const char *password) 215 { 216 int r; 217 u_char type = lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK; 218 struct sshbuf *msg; 219 220 if ((msg = sshbuf_new()) == NULL) 221 return SSH_ERR_ALLOC_FAIL; 222 if ((r = sshbuf_put_u8(msg, type)) != 0 || 223 (r = sshbuf_put_cstring(msg, password)) != 0 || 224 (r = ssh_request_reply_decode(sock, msg)) != 0) 225 goto out; 226 /* success */ 227 r = 0; 228 out: 229 sshbuf_free(msg); 230 return r; 231 } 232 233 234 static int 235 deserialise_identity2(struct sshbuf *ids, struct sshkey **keyp, char **commentp) 236 { 237 int r; 238 char *comment = NULL; 239 const u_char *blob; 240 size_t blen; 241 242 if ((r = sshbuf_get_string_direct(ids, &blob, &blen)) != 0 || 243 (r = sshbuf_get_cstring(ids, &comment, NULL)) != 0) 244 goto out; 245 if ((r = sshkey_from_blob(blob, blen, keyp)) != 0) 246 goto out; 247 if (commentp != NULL) { 248 *commentp = comment; 249 comment = NULL; 250 } 251 r = 0; 252 out: 253 free(comment); 254 return r; 255 } 256 257 /* 258 * Fetch list of identities held by the agent. 259 */ 260 int 261 ssh_fetch_identitylist(int sock, struct ssh_identitylist **idlp) 262 { 263 u_char type; 264 u_int32_t num, i; 265 struct sshbuf *msg; 266 struct ssh_identitylist *idl = NULL; 267 int r; 268 269 /* 270 * Send a message to the agent requesting for a list of the 271 * identities it can represent. 272 */ 273 if ((msg = sshbuf_new()) == NULL) 274 return SSH_ERR_ALLOC_FAIL; 275 if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_REQUEST_IDENTITIES)) != 0) 276 goto out; 277 278 if ((r = ssh_request_reply(sock, msg, msg)) != 0) 279 goto out; 280 281 /* Get message type, and verify that we got a proper answer. */ 282 if ((r = sshbuf_get_u8(msg, &type)) != 0) 283 goto out; 284 if (agent_failed(type)) { 285 r = SSH_ERR_AGENT_FAILURE; 286 goto out; 287 } else if (type != SSH2_AGENT_IDENTITIES_ANSWER) { 288 r = SSH_ERR_INVALID_FORMAT; 289 goto out; 290 } 291 292 /* Get the number of entries in the response and check it for sanity. */ 293 if ((r = sshbuf_get_u32(msg, &num)) != 0) 294 goto out; 295 if (num > MAX_AGENT_IDENTITIES) { 296 r = SSH_ERR_INVALID_FORMAT; 297 goto out; 298 } 299 if (num == 0) { 300 r = SSH_ERR_AGENT_NO_IDENTITIES; 301 goto out; 302 } 303 304 /* Deserialise the response into a list of keys/comments */ 305 if ((idl = calloc(1, sizeof(*idl))) == NULL || 306 (idl->keys = calloc(num, sizeof(*idl->keys))) == NULL || 307 (idl->comments = calloc(num, sizeof(*idl->comments))) == NULL) { 308 r = SSH_ERR_ALLOC_FAIL; 309 goto out; 310 } 311 for (i = 0; i < num;) { 312 if ((r = deserialise_identity2(msg, &(idl->keys[i]), 313 &(idl->comments[i]))) != 0) { 314 if (r == SSH_ERR_KEY_TYPE_UNKNOWN) { 315 /* Gracefully skip unknown key types */ 316 num--; 317 continue; 318 } else 319 goto out; 320 } 321 i++; 322 } 323 idl->nkeys = num; 324 *idlp = idl; 325 idl = NULL; 326 r = 0; 327 out: 328 sshbuf_free(msg); 329 if (idl != NULL) 330 ssh_free_identitylist(idl); 331 return r; 332 } 333 334 void 335 ssh_free_identitylist(struct ssh_identitylist *idl) 336 { 337 size_t i; 338 339 if (idl == NULL) 340 return; 341 for (i = 0; i < idl->nkeys; i++) { 342 if (idl->keys != NULL) 343 sshkey_free(idl->keys[i]); 344 if (idl->comments != NULL) 345 free(idl->comments[i]); 346 } 347 free(idl->keys); 348 free(idl->comments); 349 free(idl); 350 } 351 352 /* 353 * Check if the ssh agent has a given key. 354 * Returns 0 if found, or a negative SSH_ERR_* error code on failure. 355 */ 356 int 357 ssh_agent_has_key(int sock, const struct sshkey *key) 358 { 359 int r, ret = SSH_ERR_KEY_NOT_FOUND; 360 size_t i; 361 struct ssh_identitylist *idlist = NULL; 362 363 if ((r = ssh_fetch_identitylist(sock, &idlist)) != 0) { 364 return r; 365 } 366 367 for (i = 0; i < idlist->nkeys; i++) { 368 if (sshkey_equal_public(idlist->keys[i], key)) { 369 ret = 0; 370 break; 371 } 372 } 373 374 ssh_free_identitylist(idlist); 375 return ret; 376 } 377 378 /* 379 * Sends a challenge (typically from a server via ssh(1)) to the agent, 380 * and waits for a response from the agent. 381 * Returns true (non-zero) if the agent gave the correct answer, zero 382 * otherwise. 383 */ 384 385 386 /* encode signature algorithm in flag bits, so we can keep the msg format */ 387 static u_int 388 agent_encode_alg(const struct sshkey *key, const char *alg) 389 { 390 if (alg != NULL && sshkey_type_plain(key->type) == KEY_RSA) { 391 if (strcmp(alg, "rsa-sha2-256") == 0 || 392 strcmp(alg, "rsa-sha2-256-cert-v01@openssh.com") == 0) 393 return SSH_AGENT_RSA_SHA2_256; 394 if (strcmp(alg, "rsa-sha2-512") == 0 || 395 strcmp(alg, "rsa-sha2-512-cert-v01@openssh.com") == 0) 396 return SSH_AGENT_RSA_SHA2_512; 397 } 398 return 0; 399 } 400 401 /* ask agent to sign data, returns err.h code on error, 0 on success */ 402 int 403 ssh_agent_sign(int sock, const struct sshkey *key, 404 u_char **sigp, size_t *lenp, 405 const u_char *data, size_t datalen, const char *alg, u_int compat) 406 { 407 struct sshbuf *msg; 408 u_char *sig = NULL, type = 0; 409 size_t len = 0; 410 u_int flags = 0; 411 int r = SSH_ERR_INTERNAL_ERROR; 412 413 *sigp = NULL; 414 *lenp = 0; 415 416 if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE) 417 return SSH_ERR_INVALID_ARGUMENT; 418 if ((msg = sshbuf_new()) == NULL) 419 return SSH_ERR_ALLOC_FAIL; 420 flags |= agent_encode_alg(key, alg); 421 if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 || 422 (r = sshkey_puts(key, msg)) != 0 || 423 (r = sshbuf_put_string(msg, data, datalen)) != 0 || 424 (r = sshbuf_put_u32(msg, flags)) != 0) 425 goto out; 426 if ((r = ssh_request_reply(sock, msg, msg)) != 0) 427 goto out; 428 if ((r = sshbuf_get_u8(msg, &type)) != 0) 429 goto out; 430 if (agent_failed(type)) { 431 r = SSH_ERR_AGENT_FAILURE; 432 goto out; 433 } else if (type != SSH2_AGENT_SIGN_RESPONSE) { 434 r = SSH_ERR_INVALID_FORMAT; 435 goto out; 436 } 437 if ((r = sshbuf_get_string(msg, &sig, &len)) != 0) 438 goto out; 439 /* Check what we actually got back from the agent. */ 440 if ((r = sshkey_check_sigtype(sig, len, alg)) != 0) 441 goto out; 442 /* success */ 443 *sigp = sig; 444 *lenp = len; 445 sig = NULL; 446 len = 0; 447 r = 0; 448 out: 449 freezero(sig, len); 450 sshbuf_free(msg); 451 return r; 452 } 453 454 /* Encode key for a message to the agent. */ 455 456 457 static int 458 encode_constraints(struct sshbuf *m, u_int life, u_int confirm, u_int maxsign, 459 const char *provider) 460 { 461 int r; 462 463 if (life != 0) { 464 if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_LIFETIME)) != 0 || 465 (r = sshbuf_put_u32(m, life)) != 0) 466 goto out; 467 } 468 if (confirm != 0) { 469 if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_CONFIRM)) != 0) 470 goto out; 471 } 472 if (maxsign != 0) { 473 if ((r = sshbuf_put_u8(m, SSH_AGENT_CONSTRAIN_MAXSIGN)) != 0 || 474 (r = sshbuf_put_u32(m, maxsign)) != 0) 475 goto out; 476 } 477 if (provider != NULL) { 478 if ((r = sshbuf_put_u8(m, 479 SSH_AGENT_CONSTRAIN_EXTENSION)) != 0 || 480 (r = sshbuf_put_cstring(m, 481 "sk-provider@openssh.com")) != 0 || 482 (r = sshbuf_put_cstring(m, provider)) != 0) 483 goto out; 484 } 485 r = 0; 486 out: 487 return r; 488 } 489 490 /* 491 * Adds an identity to the authentication server. 492 * This call is intended only for use by ssh-add(1) and like applications. 493 */ 494 int 495 ssh_add_identity_constrained(int sock, struct sshkey *key, 496 const char *comment, u_int life, u_int confirm, u_int maxsign, 497 const char *provider) 498 { 499 struct sshbuf *msg; 500 int r, constrained = (life || confirm || maxsign || provider); 501 u_char type; 502 503 if ((msg = sshbuf_new()) == NULL) 504 return SSH_ERR_ALLOC_FAIL; 505 506 switch (key->type) { 507 #ifdef WITH_OPENSSL 508 case KEY_RSA: 509 case KEY_RSA_CERT: 510 case KEY_DSA: 511 case KEY_DSA_CERT: 512 case KEY_ECDSA: 513 case KEY_ECDSA_CERT: 514 case KEY_ECDSA_SK: 515 case KEY_ECDSA_SK_CERT: 516 #endif 517 case KEY_ED25519: 518 case KEY_ED25519_CERT: 519 case KEY_ED25519_SK: 520 case KEY_ED25519_SK_CERT: 521 case KEY_XMSS: 522 case KEY_XMSS_CERT: 523 type = constrained ? 524 SSH2_AGENTC_ADD_ID_CONSTRAINED : 525 SSH2_AGENTC_ADD_IDENTITY; 526 if ((r = sshbuf_put_u8(msg, type)) != 0 || 527 (r = sshkey_private_serialize_maxsign(key, msg, maxsign, 528 0)) != 0 || 529 (r = sshbuf_put_cstring(msg, comment)) != 0) 530 goto out; 531 break; 532 default: 533 r = SSH_ERR_INVALID_ARGUMENT; 534 goto out; 535 } 536 if (constrained && 537 (r = encode_constraints(msg, life, confirm, maxsign, 538 provider)) != 0) 539 goto out; 540 if ((r = ssh_request_reply_decode(sock, msg)) != 0) 541 goto out; 542 /* success */ 543 r = 0; 544 out: 545 sshbuf_free(msg); 546 return r; 547 } 548 549 /* 550 * Removes an identity from the authentication server. 551 * This call is intended only for use by ssh-add(1) and like applications. 552 */ 553 int 554 ssh_remove_identity(int sock, const struct sshkey *key) 555 { 556 struct sshbuf *msg; 557 int r; 558 u_char *blob = NULL; 559 size_t blen; 560 561 if ((msg = sshbuf_new()) == NULL) 562 return SSH_ERR_ALLOC_FAIL; 563 564 if (key->type != KEY_UNSPEC) { 565 if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) 566 goto out; 567 if ((r = sshbuf_put_u8(msg, 568 SSH2_AGENTC_REMOVE_IDENTITY)) != 0 || 569 (r = sshbuf_put_string(msg, blob, blen)) != 0) 570 goto out; 571 } else { 572 r = SSH_ERR_INVALID_ARGUMENT; 573 goto out; 574 } 575 if ((r = ssh_request_reply_decode(sock, msg)) != 0) 576 goto out; 577 /* success */ 578 r = 0; 579 out: 580 if (blob != NULL) 581 freezero(blob, blen); 582 sshbuf_free(msg); 583 return r; 584 } 585 586 /* 587 * Add/remove an token-based identity from the authentication server. 588 * This call is intended only for use by ssh-add(1) and like applications. 589 */ 590 int 591 ssh_update_card(int sock, int add, const char *reader_id, const char *pin, 592 u_int life, u_int confirm) 593 { 594 struct sshbuf *msg; 595 int r, constrained = (life || confirm); 596 u_char type; 597 598 if (add) { 599 type = constrained ? 600 SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED : 601 SSH_AGENTC_ADD_SMARTCARD_KEY; 602 } else 603 type = SSH_AGENTC_REMOVE_SMARTCARD_KEY; 604 605 if ((msg = sshbuf_new()) == NULL) 606 return SSH_ERR_ALLOC_FAIL; 607 if ((r = sshbuf_put_u8(msg, type)) != 0 || 608 (r = sshbuf_put_cstring(msg, reader_id)) != 0 || 609 (r = sshbuf_put_cstring(msg, pin)) != 0) 610 goto out; 611 if (constrained && 612 (r = encode_constraints(msg, life, confirm, 0, NULL)) != 0) 613 goto out; 614 if ((r = ssh_request_reply_decode(sock, msg)) != 0) 615 goto out; 616 /* success */ 617 r = 0; 618 out: 619 sshbuf_free(msg); 620 return r; 621 } 622 623 /* 624 * Removes all identities from the agent. 625 * This call is intended only for use by ssh-add(1) and like applications. 626 * 627 * This supports the SSH protocol 1 message to because, when clearing all 628 * keys from an agent, we generally want to clear both protocol v1 and v2 629 * keys. 630 */ 631 int 632 ssh_remove_all_identities(int sock, int version) 633 { 634 struct sshbuf *msg; 635 u_char type = (version == 1) ? 636 SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES : 637 SSH2_AGENTC_REMOVE_ALL_IDENTITIES; 638 int r; 639 640 if ((msg = sshbuf_new()) == NULL) 641 return SSH_ERR_ALLOC_FAIL; 642 if ((r = sshbuf_put_u8(msg, type)) != 0) 643 goto out; 644 if ((r = ssh_request_reply_decode(sock, msg)) != 0) 645 goto out; 646 /* success */ 647 r = 0; 648 out: 649 sshbuf_free(msg); 650 return r; 651 } 652 653 /* Binds a session ID to a hostkey via the initial KEX signature. */ 654 int 655 ssh_agent_bind_hostkey(int sock, const struct sshkey *key, 656 const struct sshbuf *session_id, const struct sshbuf *signature, 657 int forwarding) 658 { 659 struct sshbuf *msg; 660 int r; 661 662 if (key == NULL || session_id == NULL || signature == NULL) 663 return SSH_ERR_INVALID_ARGUMENT; 664 if ((msg = sshbuf_new()) == NULL) 665 return SSH_ERR_ALLOC_FAIL; 666 if ((r = sshbuf_put_u8(msg, SSH_AGENTC_EXTENSION)) != 0 || 667 (r = sshbuf_put_cstring(msg, "session-bind@openssh.com")) != 0 || 668 (r = sshkey_puts(key, msg)) != 0 || 669 (r = sshbuf_put_stringb(msg, session_id)) != 0 || 670 (r = sshbuf_put_stringb(msg, signature)) != 0 || 671 (r = sshbuf_put_u8(msg, forwarding ? 1 : 0)) != 0) 672 goto out; 673 if ((r = ssh_request_reply_decode(sock, msg)) != 0) 674 goto out; 675 /* success */ 676 r = 0; 677 out: 678 sshbuf_free(msg); 679 return r; 680 } 681