sshconnect2.c

   1 /*
   2  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23  */
  24
  25 #include "includes.h"
  26 RCSID("$OpenBSD: sshconnect2.c,v 1.120 2003/06/24 08:23:46 markus Exp $");
  27
  28 #ifdef KRB5
  29 #include <krb5.h>
  30 #ifndef HEIMDAL
  31 #define krb5_get_err_text(context,code) error_message(code)
  32 #endif /* !HEIMDAL */
  33 #endif
  34
  35 #include "openbsd-compat/sys-queue.h"
  36
  37 #include "ssh.h"
  38 #include "ssh2.h"
  39 #include "xmalloc.h"
  40 #include "buffer.h"
  41 #include "packet.h"
  42 #include "compat.h"
  43 #include "bufaux.h"
  44 #include "cipher.h"
  45 #include "kex.h"
  46 #include "myproposal.h"
  47 #include "sshconnect.h"
  48 #include "authfile.h"
  49 #include "dh.h"
  50 #include "authfd.h"
  51 #include "log.h"
  52 #include "readconf.h"
  53 #include "readpass.h"
  54 #include "match.h"
  55 #include "dispatch.h"
  56 #include "canohost.h"
  57 #include "msg.h"
  58 #include "pathnames.h"
  59
  60 /* import */
  61 extern char *client_version_string;
  62 extern char *server_version_string;
  63 extern Options options;
  64
  65 /*
  66  * SSH2 key exchange
  67  */
  68
  69 u_char *session_id2 = NULL;
  70 u_int session_id2_len = 0;
  71
  72 char *xxx_host;
  73 struct sockaddr *xxx_hostaddr;
  74
  75 Kex *xxx_kex = NULL;
  76
  77 static int
  78 verify_host_key_callback(Key *hostkey)
  79 {
  80         if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
  81                 fatal("Host key verification failed.");
  82         return 0;
  83 }
  84
  85 void
  86 ssh_kex2(char *host, struct sockaddr *hostaddr)
  87 {
  88         Kex *kex;
  89
  90         xxx_host = host;
  91         xxx_hostaddr = hostaddr;
  92
  93         if (options.ciphers == (char *)-1) {
  94                 logit("No valid ciphers for protocol version 2 given, using defaults.");
  95                 options.ciphers = NULL;
  96         }
  97         if (options.ciphers != NULL) {
  98                 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
  99                 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
 100         }
 101         myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 102             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
 103         myproposal[PROPOSAL_ENC_ALGS_STOC] =
 104             compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
 105         if (options.compression) {
 106                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 107                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib,none";
 108         } else {
 109                 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
 110                 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib";
 111         }
 112         if (options.macs != NULL) {
 113                 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
 114                 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
 115         }
 116         if (options.hostkeyalgorithms != NULL)
 117                 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
 118                     options.hostkeyalgorithms;
 119
 120         if (options.rekey_limit)
 121                 packet_set_rekey_limit(options.rekey_limit);
 122
 123         /* start key exchange */
 124         kex = kex_setup(myproposal);
 125         kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
 126         kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
 127         kex->client_version_string=client_version_string;
 128         kex->server_version_string=server_version_string;
 129         kex->verify_host_key=&verify_host_key_callback;
 130
 131         xxx_kex = kex;
 132
 133         dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
 134
 135         session_id2 = kex->session_id;
 136         session_id2_len = kex->session_id_len;
 137
 138 #ifdef DEBUG_KEXDH
 139         /* send 1st encrypted/maced/compressed message */
 140         packet_start(SSH2_MSG_IGNORE);
 141         packet_put_cstring("markus");
 142         packet_send();
 143         packet_write_wait();
 144 #endif
 145 }
 146
 147 /*
 148  * Authenticate user
 149  */
 150
 151 typedef struct Authctxt Authctxt;
 152 typedef struct Authmethod Authmethod;
 153 typedef struct identity Identity;
 154 typedef struct idlist Idlist;
 155
 156 struct identity {
 157         TAILQ_ENTRY(identity) next;
 158         AuthenticationConnection *ac;   /* set if agent supports key */
 159         Key     *key;                   /* public/private key */
 160         char    *filename;              /* comment for agent-only keys */
 161         int     tried;
 162         int     isprivate;              /* key points to the private key */
 163 };
 164 TAILQ_HEAD(idlist, identity);
 165
 166 struct Authctxt {
 167         const char *server_user;
 168         const char *local_user;
 169         const char *host;
 170         const char *service;
 171         Authmethod *method;
 172         int success;
 173         char *authlist;
 174         /* pubkey */
 175         Idlist keys;
 176         AuthenticationConnection *agent;
 177         /* hostbased */
 178         Sensitive *sensitive;
 179         /* kbd-interactive */
 180         int info_req_seen;
 181 };
 182 struct Authmethod {
 183         char    *name;          /* string to compare against server's list */
 184         int     (*userauth)(Authctxt *authctxt);
 185         int     *enabled;       /* flag in option struct that enables method */
 186         int     *batch_flag;    /* flag in option struct that disables method */
 187 };
 188
 189 void    input_userauth_success(int, u_int32_t, void *);
 190 void    input_userauth_failure(int, u_int32_t, void *);
 191 void    input_userauth_banner(int, u_int32_t, void *);
 192 void    input_userauth_error(int, u_int32_t, void *);
 193 void    input_userauth_info_req(int, u_int32_t, void *);
 194 void    input_userauth_pk_ok(int, u_int32_t, void *);
 195 void    input_userauth_passwd_changereq(int, u_int32_t, void *);
 196
 197 int     userauth_none(Authctxt *);
 198 int     userauth_pubkey(Authctxt *);
 199 int     userauth_passwd(Authctxt *);
 200 int     userauth_kbdint(Authctxt *);
 201 int     userauth_hostbased(Authctxt *);
 202 int     userauth_kerberos(Authctxt *);
 203
 204 void    userauth(Authctxt *, char *);
 205
 206 static int sign_and_send_pubkey(Authctxt *, Identity *);
 207 static void pubkey_prepare(Authctxt *);
 208 static void pubkey_cleanup(Authctxt *);
 209 static Key *load_identity_file(char *);
 210
 211 static Authmethod *authmethod_get(char *authlist);
 212 static Authmethod *authmethod_lookup(const char *name);
 213 static char *authmethods_get(void);
 214
 215 Authmethod authmethods[] = {
 216         {"hostbased",
 217                 userauth_hostbased,
 218                 &options.hostbased_authentication,
 219                 NULL},
 220 #if KRB5
 221         {"kerberos-2@ssh.com",
 222                 userauth_kerberos,
 223                 &options.kerberos_authentication,
 224                 NULL},
 225 #endif
 226         {"publickey",
 227                 userauth_pubkey,
 228                 &options.pubkey_authentication,
 229                 NULL},
 230         {"keyboard-interactive",
 231                 userauth_kbdint,
 232                 &options.kbd_interactive_authentication,
 233                 &options.batch_mode},
 234         {"password",
 235                 userauth_passwd,
 236                 &options.password_authentication,
 237                 &options.batch_mode},
 238         {"none",
 239                 userauth_none,
 240                 NULL,
 241                 NULL},
 242         {NULL, NULL, NULL, NULL}
 243 };
 244
 245 void
 246 ssh_userauth2(const char *local_user, const char *server_user, char *host,
 247     Sensitive *sensitive)
 248 {
 249         Authctxt authctxt;
 250         int type;
 251
 252         if (options.challenge_response_authentication)
 253                 options.kbd_interactive_authentication = 1;
 254
 255         packet_start(SSH2_MSG_SERVICE_REQUEST);
 256         packet_put_cstring("ssh-userauth");
 257         packet_send();
 258         debug("SSH2_MSG_SERVICE_REQUEST sent");
 259         packet_write_wait();
 260         type = packet_read();
 261         if (type != SSH2_MSG_SERVICE_ACCEPT)
 262                 fatal("Server denied authentication request: %d", type);
 263         if (packet_remaining() > 0) {
 264                 char *reply = packet_get_string(NULL);
 265                 debug2("service_accept: %s", reply);
 266                 xfree(reply);
 267         } else {
 268                 debug2("buggy server: service_accept w/o service");
 269         }
 270         packet_check_eom();
 271         debug("SSH2_MSG_SERVICE_ACCEPT received");
 272
 273         if (options.preferred_authentications == NULL)
 274                 options.preferred_authentications = authmethods_get();
 275
 276         /* setup authentication context */
 277         memset(&authctxt, 0, sizeof(authctxt));
 278         pubkey_prepare(&authctxt);
 279         authctxt.server_user = server_user;
 280         authctxt.local_user = local_user;
 281         authctxt.host = host;
 282         authctxt.service = "ssh-connection";            /* service name */
 283         authctxt.success = 0;
 284         authctxt.method = authmethod_lookup("none");
 285         authctxt.authlist = NULL;
 286         authctxt.sensitive = sensitive;
 287         authctxt.info_req_seen = 0;
 288         if (authctxt.method == NULL)
 289                 fatal("ssh_userauth2: internal error: cannot send userauth none request");
 290
 291         /* initial userauth request */
 292         userauth_none(&authctxt);
 293
 294         dispatch_init(&input_userauth_error);
 295         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
 296         dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
 297         dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
 298         dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt);     /* loop until success */
 299
 300         pubkey_cleanup(&authctxt);
 301         dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
 302
 303         debug("Authentication succeeded (%s).", authctxt.method->name);
 304 }
 305
 306 void
 307 userauth(Authctxt *authctxt, char *authlist)
 308 {
 309         if (authlist == NULL) {
 310                 authlist = authctxt->authlist;
 311         } else {
 312                 if (authctxt->authlist)
 313                         xfree(authctxt->authlist);
 314                 authctxt->authlist = authlist;
 315         }
 316         for (;;) {
 317                 Authmethod *method = authmethod_get(authlist);
 318                 if (method == NULL)
 319                         fatal("Permission denied (%s).", authlist);
 320                 authctxt->method = method;
 321
 322                 /* reset the per method handler */
 323                 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
 324                     SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
 325
 326                 /* and try new method */
 327                 if (method->userauth(authctxt) != 0) {
 328                         debug2("we sent a %s packet, wait for reply", method->name);
 329                         break;
 330                 } else {
 331                         debug2("we did not send a packet, disable method");
 332                         method->enabled = NULL;
 333                 }
 334         }
 335 }
 336
 337 void
 338 input_userauth_error(int type, u_int32_t seq, void *ctxt)
 339 {
 340         fatal("input_userauth_error: bad message during authentication: "
 341            "type %d", type);
 342 }
 343
 344 void
 345 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
 346 {
 347         char *msg, *lang;
 348         debug3("input_userauth_banner");
 349         msg = packet_get_string(NULL);
 350         lang = packet_get_string(NULL);
 351         fprintf(stderr, "%s", msg);
 352         xfree(msg);
 353         xfree(lang);
 354 }
 355
 356 void
 357 input_userauth_success(int type, u_int32_t seq, void *ctxt)
 358 {
 359         Authctxt *authctxt = ctxt;
 360         if (authctxt == NULL)
 361                 fatal("input_userauth_success: no authentication context");
 362         if (authctxt->authlist)
 363                 xfree(authctxt->authlist);
 364         authctxt->success = 1;                  /* break out */
 365 }
 366
 367 void
 368 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
 369 {
 370         Authctxt *authctxt = ctxt;
 371         char *authlist = NULL;
 372         int partial;
 373
 374         if (authctxt == NULL)
 375                 fatal("input_userauth_failure: no authentication context");
 376
 377         authlist = packet_get_string(NULL);
 378         partial = packet_get_char();
 379         packet_check_eom();
 380
 381         if (partial != 0)
 382                 logit("Authenticated with partial success.");
 383         debug("Authentications that can continue: %s", authlist);
 384
 385         userauth(authctxt, authlist);
 386 }
 387 void
 388 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
 389 {
 390         Authctxt *authctxt = ctxt;
 391         Key *key = NULL;
 392         Identity *id = NULL;
 393         Buffer b;
 394         int pktype, sent = 0;
 395         u_int alen, blen;
 396         char *pkalg, *fp;
 397         u_char *pkblob;
 398
 399         if (authctxt == NULL)
 400                 fatal("input_userauth_pk_ok: no authentication context");
 401         if (datafellows & SSH_BUG_PKOK) {
 402                 /* this is similar to SSH_BUG_PKAUTH */
 403                 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
 404                 pkblob = packet_get_string(&blen);
 405                 buffer_init(&b);
 406                 buffer_append(&b, pkblob, blen);
 407                 pkalg = buffer_get_string(&b, &alen);
 408                 buffer_free(&b);
 409         } else {
 410                 pkalg = packet_get_string(&alen);
 411                 pkblob = packet_get_string(&blen);
 412         }
 413         packet_check_eom();
 414
 415         debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
 416
 417         if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
 418                 debug("unknown pkalg %s", pkalg);
 419                 goto done;
 420         }
 421         if ((key = key_from_blob(pkblob, blen)) == NULL) {
 422                 debug("no key from blob. pkalg %s", pkalg);
 423                 goto done;
 424         }
 425         if (key->type != pktype) {
 426                 error("input_userauth_pk_ok: type mismatch "
 427                     "for decoded key (received %d, expected %d)",
 428                     key->type, pktype);
 429                 goto done;
 430         }
 431         fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 432         debug2("input_userauth_pk_ok: fp %s", fp);
 433         xfree(fp);
 434
 435         TAILQ_FOREACH(id, &authctxt->keys, next) {
 436                 if (key_equal(key, id->key)) {
 437                         sent = sign_and_send_pubkey(authctxt, id);
 438                         break;
 439                 }
 440         }
 441 done:
 442         if (key != NULL)
 443                 key_free(key);
 444         xfree(pkalg);
 445         xfree(pkblob);
 446
 447         /* try another method if we did not send a packet */
 448         if (sent == 0)
 449                 userauth(authctxt, NULL);
 450 }
 451
 452 int
 453 userauth_none(Authctxt *authctxt)
 454 {
 455         /* initial userauth request */
 456         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 457         packet_put_cstring(authctxt->server_user);
 458         packet_put_cstring(authctxt->service);
 459         packet_put_cstring(authctxt->method->name);
 460         packet_send();
 461         return 1;
 462 }
 463
 464 int
 465 userauth_passwd(Authctxt *authctxt)
 466 {
 467         static int attempt = 0;
 468         char prompt[150];
 469         char *password;
 470
 471         if (attempt++ >= options.number_of_password_prompts)
 472                 return 0;
 473
 474         if (attempt != 1)
 475                 error("Permission denied, please try again.");
 476
 477         snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
 478             authctxt->server_user, authctxt->host);
 479         password = read_passphrase(prompt, 0);
 480         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 481         packet_put_cstring(authctxt->server_user);
 482         packet_put_cstring(authctxt->service);
 483         packet_put_cstring(authctxt->method->name);
 484         packet_put_char(0);
 485         packet_put_cstring(password);
 486         memset(password, 0, strlen(password));
 487         xfree(password);
 488         packet_add_padding(64);
 489         packet_send();
 490
 491         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
 492             &input_userauth_passwd_changereq);
 493
 494         return 1;
 495 }
 496 /*
 497  * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
 498  */
 499 void
 500 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
 501 {
 502         Authctxt *authctxt = ctxt;
 503         char *info, *lang, *password = NULL, *retype = NULL;
 504         char prompt[150];
 505
 506         debug2("input_userauth_passwd_changereq");
 507
 508         if (authctxt == NULL)
 509                 fatal("input_userauth_passwd_changereq: "
 510                     "no authentication context");
 511
 512         info = packet_get_string(NULL);
 513         lang = packet_get_string(NULL);
 514         if (strlen(info) > 0)
 515                 logit("%s", info);
 516         xfree(info);
 517         xfree(lang);
 518         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 519         packet_put_cstring(authctxt->server_user);
 520         packet_put_cstring(authctxt->service);
 521         packet_put_cstring(authctxt->method->name);
 522         packet_put_char(1);                     /* additional info */
 523         snprintf(prompt, sizeof(prompt),
 524             "Enter %.30s@%.128s's old password: ",
 525             authctxt->server_user, authctxt->host);
 526         password = read_passphrase(prompt, 0);
 527         packet_put_cstring(password);
 528         memset(password, 0, strlen(password));
 529         xfree(password);
 530         password = NULL;
 531         while (password == NULL) {
 532                 snprintf(prompt, sizeof(prompt),
 533                     "Enter %.30s@%.128s's new password: ",
 534                     authctxt->server_user, authctxt->host);
 535                 password = read_passphrase(prompt, RP_ALLOW_EOF);
 536                 if (password == NULL) {
 537                         /* bail out */
 538                         return;
 539                 }
 540                 snprintf(prompt, sizeof(prompt),
 541                     "Retype %.30s@%.128s's new password: ",
 542                     authctxt->server_user, authctxt->host);
 543                 retype = read_passphrase(prompt, 0);
 544                 if (strcmp(password, retype) != 0) {
 545                         memset(password, 0, strlen(password));
 546                         xfree(password);
 547                         logit("Mismatch; try again, EOF to quit.");
 548                         password = NULL;
 549                 }
 550                 memset(retype, 0, strlen(retype));
 551                 xfree(retype);
 552         }
 553         packet_put_cstring(password);
 554         memset(password, 0, strlen(password));
 555         xfree(password);
 556         packet_add_padding(64);
 557         packet_send();
 558
 559         dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
 560             &input_userauth_passwd_changereq);
 561 }
 562
 563 static int
 564 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
 565     u_char *data, u_int datalen)
 566 {
 567         Key *prv;
 568         int ret;
 569
 570         /* the agent supports this key */
 571         if (id->ac)
 572                 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
 573                     data, datalen));
 574         /*
 575          * we have already loaded the private key or
 576          * the private key is stored in external hardware
 577          */
 578         if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
 579                 return (key_sign(id->key, sigp, lenp, data, datalen));
 580         /* load the private key from the file */
 581         if ((prv = load_identity_file(id->filename)) == NULL)
 582                 return (-1);
 583         ret = key_sign(prv, sigp, lenp, data, datalen);
 584         key_free(prv);
 585         return (ret);
 586 }
 587
 588 static int
 589 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
 590 {
 591         Buffer b;
 592         u_char *blob, *signature;
 593         u_int bloblen, slen;
 594         u_int skip = 0;
 595         int ret = -1;
 596         int have_sig = 1;
 597
 598         debug3("sign_and_send_pubkey");
 599
 600         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
 601                 /* we cannot handle this key */
 602                 debug3("sign_and_send_pubkey: cannot handle key");
 603                 return 0;
 604         }
 605         /* data to be signed */
 606         buffer_init(&b);
 607         if (datafellows & SSH_OLD_SESSIONID) {
 608                 buffer_append(&b, session_id2, session_id2_len);
 609                 skip = session_id2_len;
 610         } else {
 611                 buffer_put_string(&b, session_id2, session_id2_len);
 612                 skip = buffer_len(&b);
 613         }
 614         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
 615         buffer_put_cstring(&b, authctxt->server_user);
 616         buffer_put_cstring(&b,
 617             datafellows & SSH_BUG_PKSERVICE ?
 618             "ssh-userauth" :
 619             authctxt->service);
 620         if (datafellows & SSH_BUG_PKAUTH) {
 621                 buffer_put_char(&b, have_sig);
 622         } else {
 623                 buffer_put_cstring(&b, authctxt->method->name);
 624                 buffer_put_char(&b, have_sig);
 625                 buffer_put_cstring(&b, key_ssh_name(id->key));
 626         }
 627         buffer_put_string(&b, blob, bloblen);
 628
 629         /* generate signature */
 630         ret = identity_sign(id, &signature, &slen,
 631             buffer_ptr(&b), buffer_len(&b));
 632         if (ret == -1) {
 633                 xfree(blob);
 634                 buffer_free(&b);
 635                 return 0;
 636         }
 637 #ifdef DEBUG_PK
 638         buffer_dump(&b);
 639 #endif
 640         if (datafellows & SSH_BUG_PKSERVICE) {
 641                 buffer_clear(&b);
 642                 buffer_append(&b, session_id2, session_id2_len);
 643                 skip = session_id2_len;
 644                 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
 645                 buffer_put_cstring(&b, authctxt->server_user);
 646                 buffer_put_cstring(&b, authctxt->service);
 647                 buffer_put_cstring(&b, authctxt->method->name);
 648                 buffer_put_char(&b, have_sig);
 649                 if (!(datafellows & SSH_BUG_PKAUTH))
 650                         buffer_put_cstring(&b, key_ssh_name(id->key));
 651                 buffer_put_string(&b, blob, bloblen);
 652         }
 653         xfree(blob);
 654
 655         /* append signature */
 656         buffer_put_string(&b, signature, slen);
 657         xfree(signature);
 658
 659         /* skip session id and packet type */
 660         if (buffer_len(&b) < skip + 1)
 661                 fatal("userauth_pubkey: internal error");
 662         buffer_consume(&b, skip + 1);
 663
 664         /* put remaining data from buffer into packet */
 665         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 666         packet_put_raw(buffer_ptr(&b), buffer_len(&b));
 667         buffer_free(&b);
 668         packet_send();
 669
 670         return 1;
 671 }
 672
 673 static int
 674 send_pubkey_test(Authctxt *authctxt, Identity *id)
 675 {
 676         u_char *blob;
 677         u_int bloblen, have_sig = 0;
 678
 679         debug3("send_pubkey_test");
 680
 681         if (key_to_blob(id->key, &blob, &bloblen) == 0) {
 682                 /* we cannot handle this key */
 683                 debug3("send_pubkey_test: cannot handle key");
 684                 return 0;
 685         }
 686         /* register callback for USERAUTH_PK_OK message */
 687         dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
 688
 689         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 690         packet_put_cstring(authctxt->server_user);
 691         packet_put_cstring(authctxt->service);
 692         packet_put_cstring(authctxt->method->name);
 693         packet_put_char(have_sig);
 694         if (!(datafellows & SSH_BUG_PKAUTH))
 695                 packet_put_cstring(key_ssh_name(id->key));
 696         packet_put_string(blob, bloblen);
 697         xfree(blob);
 698         packet_send();
 699         return 1;
 700 }
 701
 702 static Key *
 703 load_identity_file(char *filename)
 704 {
 705         Key *private;
 706         char prompt[300], *passphrase;
 707         int quit, i;
 708         struct stat st;
 709
 710         if (stat(filename, &st) < 0) {
 711                 debug3("no such identity: %s", filename);
 712                 return NULL;
 713         }
 714         private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
 715         if (private == NULL) {
 716                 if (options.batch_mode)
 717                         return NULL;
 718                 snprintf(prompt, sizeof prompt,
 719                     "Enter passphrase for key '%.100s': ", filename);
 720                 for (i = 0; i < options.number_of_password_prompts; i++) {
 721                         passphrase = read_passphrase(prompt, 0);
 722                         if (strcmp(passphrase, "") != 0) {
 723                                 private = key_load_private_type(KEY_UNSPEC, filename,
 724                                     passphrase, NULL);
 725                                 quit = 0;
 726                         } else {
 727                                 debug2("no passphrase given, try next key");
 728                                 quit = 1;
 729                         }
 730                         memset(passphrase, 0, strlen(passphrase));
 731                         xfree(passphrase);
 732                         if (private != NULL || quit)
 733                                 break;
 734                         debug2("bad passphrase given, try again...");
 735                 }
 736         }
 737         return private;
 738 }
 739
 740 /*
 741  * try keys in the following order:
 742  *      1. agent keys that are found in the config file
 743  *      2. other agent keys
 744  *      3. keys that are only listed in the config file
 745  */
 746 static void
 747 pubkey_prepare(Authctxt *authctxt)
 748 {
 749         Identity *id;
 750         Idlist agent, files, *preferred;
 751         Key *key;
 752         AuthenticationConnection *ac;
 753         char *comment;
 754         int i, found;
 755
 756         TAILQ_INIT(&agent);     /* keys from the agent */
 757         TAILQ_INIT(&files);     /* keys from the config file */
 758         preferred = &authctxt->keys;
 759         TAILQ_INIT(preferred);  /* preferred order of keys */
 760
 761         /* list of keys stored in the filesystem */
 762         for (i = 0; i < options.num_identity_files; i++) {
 763                 key = options.identity_keys[i];
 764                 if (key && key->type == KEY_RSA1)
 765                         continue;
 766                 options.identity_keys[i] = NULL;
 767                 id = xmalloc(sizeof(*id));
 768                 memset(id, 0, sizeof(*id));
 769                 id->key = key;
 770                 id->filename = xstrdup(options.identity_files[i]);
 771                 TAILQ_INSERT_TAIL(&files, id, next);
 772         }
 773         /* list of keys supported by the agent */
 774         if ((ac = ssh_get_authentication_connection())) {
 775                 for (key = ssh_get_first_identity(ac, &comment, 2);
 776                     key != NULL;
 777                     key = ssh_get_next_identity(ac, &comment, 2)) {
 778                         found = 0;
 779                         TAILQ_FOREACH(id, &files, next) {
 780                                 /* agent keys from the config file are preferred */
 781                                 if (key_equal(key, id->key)) {
 782                                         key_free(key);
 783                                         xfree(comment);
 784                                         TAILQ_REMOVE(&files, id, next);
 785                                         TAILQ_INSERT_TAIL(preferred, id, next);
 786                                         id->ac = ac;
 787                                         found = 1;
 788                                         break;
 789                                 }
 790                         }
 791                         if (!found) {
 792                                 id = xmalloc(sizeof(*id));
 793                                 memset(id, 0, sizeof(*id));
 794                                 id->key = key;
 795                                 id->filename = comment;
 796                                 id->ac = ac;
 797                                 TAILQ_INSERT_TAIL(&agent, id, next);
 798                         }
 799                 }
 800                 /* append remaining agent keys */
 801                 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
 802                         TAILQ_REMOVE(&agent, id, next);
 803                         TAILQ_INSERT_TAIL(preferred, id, next);
 804                 }
 805                 authctxt->agent = ac;
 806         }
 807         /* append remaining keys from the config file */
 808         for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
 809                 TAILQ_REMOVE(&files, id, next);
 810                 TAILQ_INSERT_TAIL(preferred, id, next);
 811         }
 812         TAILQ_FOREACH(id, preferred, next) {
 813                 debug2("key: %s (%p)", id->filename, id->key);
 814         }
 815 }
 816
 817 static void
 818 pubkey_cleanup(Authctxt *authctxt)
 819 {
 820         Identity *id;
 821
 822         if (authctxt->agent != NULL)
 823                 ssh_close_authentication_connection(authctxt->agent);
 824         for (id = TAILQ_FIRST(&authctxt->keys); id;
 825             id = TAILQ_FIRST(&authctxt->keys)) {
 826                 TAILQ_REMOVE(&authctxt->keys, id, next);
 827                 if (id->key)
 828                         key_free(id->key);
 829                 if (id->filename)
 830                         xfree(id->filename);
 831                 xfree(id);
 832         }
 833 }
 834
 835 int
 836 userauth_pubkey(Authctxt *authctxt)
 837 {
 838         Identity *id;
 839         int sent = 0;
 840
 841         while ((id = TAILQ_FIRST(&authctxt->keys))) {
 842                 if (id->tried++)
 843                         return (0);
 844                 TAILQ_REMOVE(&authctxt->keys, id, next);
 845                 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
 846                 /*
 847                  * send a test message if we have the public key. for
 848                  * encrypted keys we cannot do this and have to load the
 849                  * private key instead
 850                  */
 851                 if (id->key && id->key->type != KEY_RSA1) {
 852                         debug("Offering public key: %s", id->filename);
 853                         sent = send_pubkey_test(authctxt, id);
 854                 } else if (id->key == NULL) {
 855                         debug("Trying private key: %s", id->filename);
 856                         id->key = load_identity_file(id->filename);
 857                         if (id->key != NULL) {
 858                                 id->isprivate = 1;
 859                                 sent = sign_and_send_pubkey(authctxt, id);
 860                                 key_free(id->key);
 861                                 id->key = NULL;
 862                         }
 863                 }
 864                 if (sent)
 865                         return (sent);
 866         }
 867         return (0);
 868 }
 869
 870 /*
 871  * Send userauth request message specifying keyboard-interactive method.
 872  */
 873 int
 874 userauth_kbdint(Authctxt *authctxt)
 875 {
 876         static int attempt = 0;
 877
 878         if (attempt++ >= options.number_of_password_prompts)
 879                 return 0;
 880         /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
 881         if (attempt > 1 && !authctxt->info_req_seen) {
 882                 debug3("userauth_kbdint: disable: no info_req_seen");
 883                 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
 884                 return 0;
 885         }
 886
 887         debug2("userauth_kbdint");
 888         packet_start(SSH2_MSG_USERAUTH_REQUEST);
 889         packet_put_cstring(authctxt->server_user);
 890         packet_put_cstring(authctxt->service);
 891         packet_put_cstring(authctxt->method->name);
 892         packet_put_cstring("");                                 /* lang */
 893         packet_put_cstring(options.kbd_interactive_devices ?
 894             options.kbd_interactive_devices : "");
 895         packet_send();
 896
 897         dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
 898         return 1;
 899 }
 900
 901 /*
 902  * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
 903  */
 904 void
 905 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
 906 {
 907         Authctxt *authctxt = ctxt;
 908         char *name, *inst, *lang, *prompt, *response;
 909         u_int num_prompts, i;
 910         int echo = 0;
 911
 912         debug2("input_userauth_info_req");
 913
 914         if (authctxt == NULL)
 915                 fatal("input_userauth_info_req: no authentication context");
 916
 917         authctxt->info_req_seen = 1;
 918
 919         name = packet_get_string(NULL);
 920         inst = packet_get_string(NULL);
 921         lang = packet_get_string(NULL);
 922         if (strlen(name) > 0)
 923                 logit("%s", name);
 924         if (strlen(inst) > 0)
 925                 logit("%s", inst);
 926         xfree(name);
 927         xfree(inst);
 928         xfree(lang);
 929
 930         num_prompts = packet_get_int();
 931         /*
 932          * Begin to build info response packet based on prompts requested.
 933          * We commit to providing the correct number of responses, so if
 934          * further on we run into a problem that prevents this, we have to
 935          * be sure and clean this up and send a correct error response.
 936          */
 937         packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
 938         packet_put_int(num_prompts);
 939
 940         debug2("input_userauth_info_req: num_prompts %d", num_prompts);
 941         for (i = 0; i < num_prompts; i++) {
 942                 prompt = packet_get_string(NULL);
 943                 echo = packet_get_char();
 944
 945                 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
 946
 947                 packet_put_cstring(response);
 948                 memset(response, 0, strlen(response));
 949                 xfree(response);
 950                 xfree(prompt);
 951         }
 952         packet_check_eom(); /* done with parsing incoming message. */
 953
 954         packet_add_padding(64);
 955         packet_send();
 956 }
 957
 958 static int
 959 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
 960     u_char *data, u_int datalen)
 961 {
 962         Buffer b;
 963         struct stat st;
 964         pid_t pid;
 965         int to[2], from[2], status, version = 2;
 966
 967         debug2("ssh_keysign called");
 968
 969         if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
 970                 error("ssh_keysign: no installed: %s", strerror(errno));
 971                 return -1;
 972         }
 973         if (fflush(stdout) != 0)
 974                 error("ssh_keysign: fflush: %s", strerror(errno));
 975         if (pipe(to) < 0) {
 976                 error("ssh_keysign: pipe: %s", strerror(errno));
 977                 return -1;
 978         }
 979         if (pipe(from) < 0) {
 980                 error("ssh_keysign: pipe: %s", strerror(errno));
 981                 return -1;
 982         }
 983         if ((pid = fork()) < 0) {
 984                 error("ssh_keysign: fork: %s", strerror(errno));
 985                 return -1;
 986         }
 987         if (pid == 0) {
 988                 seteuid(getuid());
 989                 setuid(getuid());
 990                 close(from[0]);
 991                 if (dup2(from[1], STDOUT_FILENO) < 0)
 992                         fatal("ssh_keysign: dup2: %s", strerror(errno));
 993                 close(to[1]);
 994                 if (dup2(to[0], STDIN_FILENO) < 0)
 995                         fatal("ssh_keysign: dup2: %s", strerror(errno));
 996                 close(from[1]);
 997                 close(to[0]);
 998                 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
 999                 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1000                     strerror(errno));
1001         }
1002         close(from[1]);
1003         close(to[0]);
1004
1005         buffer_init(&b);
1006         buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1007         buffer_put_string(&b, data, datalen);
1008         ssh_msg_send(to[1], version, &b);
1009
1010         if (ssh_msg_recv(from[0], &b) < 0) {
1011                 error("ssh_keysign: no reply");
1012                 buffer_clear(&b);
1013                 return -1;
1014         }
1015         close(from[0]);
1016         close(to[1]);
1017
1018         while (waitpid(pid, &status, 0) < 0)
1019                 if (errno != EINTR)
1020                         break;
1021
1022         if (buffer_get_char(&b) != version) {
1023                 error("ssh_keysign: bad version");
1024                 buffer_clear(&b);
1025                 return -1;
1026         }
1027         *sigp = buffer_get_string(&b, lenp);
1028         buffer_clear(&b);
1029
1030         return 0;
1031 }
1032
1033 int
1034 userauth_hostbased(Authctxt *authctxt)
1035 {
1036         Key *private = NULL;
1037         Sensitive *sensitive = authctxt->sensitive;
1038         Buffer b;
1039         u_char *signature, *blob;
1040         char *chost, *pkalg, *p;
1041         const char *service;
1042         u_int blen, slen;
1043         int ok, i, len, found = 0;
1044
1045         /* check for a useful key */
1046         for (i = 0; i < sensitive->nkeys; i++) {
1047                 private = sensitive->keys[i];
1048                 if (private && private->type != KEY_RSA1) {
1049                         found = 1;
1050                         /* we take and free the key */
1051                         sensitive->keys[i] = NULL;
1052                         break;
1053                 }
1054         }
1055         if (!found) {
1056                 debug("No more client hostkeys for hostbased authentication.");
1057                 return 0;
1058         }
1059         if (key_to_blob(private, &blob, &blen) == 0) {
1060                 key_free(private);
1061                 return 0;
1062         }
1063         /* figure out a name for the client host */
1064         p = get_local_name(packet_get_connection_in());
1065         if (p == NULL) {
1066                 error("userauth_hostbased: cannot get local ipaddr/name");
1067                 key_free(private);
1068                 return 0;
1069         }
1070         len = strlen(p) + 2;
1071         chost = xmalloc(len);
1072         strlcpy(chost, p, len);
1073         strlcat(chost, ".", len);
1074         debug2("userauth_hostbased: chost %s", chost);
1075         xfree(p);
1076
1077         service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1078             authctxt->service;
1079         pkalg = xstrdup(key_ssh_name(private));
1080         buffer_init(&b);
1081         /* construct data */
1082         buffer_put_string(&b, session_id2, session_id2_len);
1083         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1084         buffer_put_cstring(&b, authctxt->server_user);
1085         buffer_put_cstring(&b, service);
1086         buffer_put_cstring(&b, authctxt->method->name);
1087         buffer_put_cstring(&b, pkalg);
1088         buffer_put_string(&b, blob, blen);
1089         buffer_put_cstring(&b, chost);
1090         buffer_put_cstring(&b, authctxt->local_user);
1091 #ifdef DEBUG_PK
1092         buffer_dump(&b);
1093 #endif
1094         if (sensitive->external_keysign)
1095                 ok = ssh_keysign(private, &signature, &slen,
1096                     buffer_ptr(&b), buffer_len(&b));
1097         else
1098                 ok = key_sign(private, &signature, &slen,
1099                     buffer_ptr(&b), buffer_len(&b));
1100         key_free(private);
1101         buffer_free(&b);
1102         if (ok != 0) {
1103                 error("key_sign failed");
1104                 xfree(chost);
1105                 xfree(pkalg);
1106                 return 0;
1107         }
1108         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1109         packet_put_cstring(authctxt->server_user);
1110         packet_put_cstring(authctxt->service);
1111         packet_put_cstring(authctxt->method->name);
1112         packet_put_cstring(pkalg);
1113         packet_put_string(blob, blen);
1114         packet_put_cstring(chost);
1115         packet_put_cstring(authctxt->local_user);
1116         packet_put_string(signature, slen);
1117         memset(signature, 's', slen);
1118         xfree(signature);
1119         xfree(chost);
1120         xfree(pkalg);
1121
1122         packet_send();
1123         return 1;
1124 }
1125
1126 #if KRB5
1127 static int
1128 ssh_krb5_helper(krb5_data *ap, krb5_context *context)
1129 {
1130         krb5_context xcontext = NULL;   /* XXX share with ssh1 */
1131         krb5_auth_context xauth_context = NULL;
1132         krb5_auth_context *auth_context;
1133         krb5_error_code problem;
1134         const char *tkfile;
1135         struct stat buf;
1136         krb5_ccache ccache = NULL;
1137         const char *remotehost;
1138         int ret;
1139
1140         memset(ap, 0, sizeof(*ap));
1141
1142         context = &xcontext;
1143         auth_context = &xauth_context;
1144
1145         problem = krb5_init_context(context);
1146         if (problem) {
1147                 debug("Kerberos v5: krb5_init_context failed");
1148                 ret = 0;
1149                 goto out;
1150         }
1151
1152         tkfile = krb5_cc_default_name(*context);
1153         if (strncmp(tkfile, "FILE:", 5) == 0)
1154                 tkfile += 5;
1155
1156         if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {
1157                 debug("Kerberos v5: could not get default ccache (permission denied).");
1158                 ret = 0;
1159                 goto out;
1160         }
1161
1162         problem = krb5_cc_default(*context, &ccache);
1163         if (problem) {
1164                 debug("Kerberos v5: krb5_cc_default failed: %s",
1165                     krb5_get_err_text(*context, problem));
1166                 ret = 0;
1167                 goto out;
1168         }
1169
1170         remotehost = get_canonical_hostname(1);
1171
1172         problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED,
1173             "host", remotehost, NULL, ccache, ap);
1174         if (problem) {
1175                 debug("Kerberos v5: krb5_mk_req failed: %s",
1176                     krb5_get_err_text(*context, problem));
1177                 ret = 0;
1178                 goto out;
1179         }
1180         ret = 1;
1181
1182  out:
1183         if (ccache != NULL)
1184                 krb5_cc_close(*context, ccache);
1185         if (*auth_context)
1186                 krb5_auth_con_free(*context, *auth_context);
1187         return (ret);
1188 }
1189
1190 int
1191 userauth_kerberos(Authctxt *authctxt)
1192 {
1193         krb5_data ap;
1194         krb5_context *context;
1195         int ret = 0;
1196
1197         if (ssh_krb5_helper(&ap, context) == 0)
1198                 goto out;
1199
1200         packet_start(SSH2_MSG_USERAUTH_REQUEST);
1201         packet_put_cstring(authctxt->server_user);
1202         packet_put_cstring(authctxt->service);
1203         packet_put_cstring(authctxt->method->name);
1204         packet_put_string(ap.data, ap.length);
1205         packet_send();
1206
1207 #ifdef HEIMDAL
1208         krb5_data_free(&ap);
1209 #else
1210         krb5_free_data_contents(*context, &ap);
1211 #endif
1212         ret = 1;
1213
1214 out:
1215         if (*context)
1216                 krb5_free_context(*context);
1217         return ret;
1218 }
1219 #endif
1220
1221 /* find auth method */
1222
1223 /*
1224  * given auth method name, if configurable options permit this method fill
1225  * in auth_ident field and return true, otherwise return false.
1226  */
1227 static int
1228 authmethod_is_enabled(Authmethod *method)
1229 {
1230         if (method == NULL)
1231                 return 0;
1232         /* return false if options indicate this method is disabled */
1233         if  (method->enabled == NULL || *method->enabled == 0)
1234                 return 0;
1235         /* return false if batch mode is enabled but method needs interactive mode */
1236         if  (method->batch_flag != NULL && *method->batch_flag != 0)
1237                 return 0;
1238         return 1;
1239 }
1240
1241 static Authmethod *
1242 authmethod_lookup(const char *name)
1243 {
1244         Authmethod *method = NULL;
1245         if (name != NULL)
1246                 for (method = authmethods; method->name != NULL; method++)
1247                         if (strcmp(name, method->name) == 0)
1248                                 return method;
1249         debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1250         return NULL;
1251 }
1252
1253 /* XXX internal state */
1254 static Authmethod *current = NULL;
1255 static char *supported = NULL;
1256 static char *preferred = NULL;
1257
1258 /*
1259  * Given the authentication method list sent by the server, return the
1260  * next method we should try.  If the server initially sends a nil list,
1261  * use a built-in default list.
1262  */
1263 static Authmethod *
1264 authmethod_get(char *authlist)
1265 {
1266         char *name = NULL;
1267         u_int next;
1268
1269         /* Use a suitable default if we're passed a nil list.  */
1270         if (authlist == NULL || strlen(authlist) == 0)
1271                 authlist = options.preferred_authentications;
1272
1273         if (supported == NULL || strcmp(authlist, supported) != 0) {
1274                 debug3("start over, passed a different list %s", authlist);
1275                 if (supported != NULL)
1276                         xfree(supported);
1277                 supported = xstrdup(authlist);
1278                 preferred = options.preferred_authentications;
1279                 debug3("preferred %s", preferred);
1280                 current = NULL;
1281         } else if (current != NULL && authmethod_is_enabled(current))
1282                 return current;
1283
1284         for (;;) {
1285                 if ((name = match_list(preferred, supported, &next)) == NULL) {
1286                         debug("No more authentication methods to try.");
1287                         current = NULL;
1288                         return NULL;
1289                 }
1290                 preferred += next;
1291                 debug3("authmethod_lookup %s", name);
1292                 debug3("remaining preferred: %s", preferred);
1293                 if ((current = authmethod_lookup(name)) != NULL &&
1294                     authmethod_is_enabled(current)) {
1295                         debug3("authmethod_is_enabled %s", name);
1296                         debug("Next authentication method: %s", name);
1297                         return current;
1298                 }
1299         }
1300 }
1301
1302 static char *
1303 authmethods_get(void)
1304 {
1305         Authmethod *method = NULL;
1306         Buffer b;
1307         char *list;
1308
1309         buffer_init(&b);
1310         for (method = authmethods; method->name != NULL; method++) {
1311                 if (authmethod_is_enabled(method)) {
1312                         if (buffer_len(&b) > 0)
1313                                 buffer_append(&b, ",", 1);
1314                         buffer_append(&b, method->name, strlen(method->name));
1315                 }
1316         }
1317         buffer_append(&b, "\0", 1);
1318         list = xstrdup(buffer_ptr(&b));
1319         buffer_free(&b);
1320         return list;
1321 }