ssh-keygen.c

   1 /* $OpenBSD: ssh-keygen.c,v 1.176 2010/01/11 10:51:07 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Identity and host key generation and maintenance.
   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
  15 #include "includes.h"
  16
  17 #include <sys/types.h>
  18 #include <sys/socket.h>
  19 #include <sys/stat.h>
  20 #include <sys/param.h>
  21
  22 #include <openssl/evp.h>
  23 #include <openssl/pem.h>
  24 #include "openbsd-compat/openssl-compat.h"
  25
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <netdb.h>
  29 #ifdef HAVE_PATHS_H
  30 # include <paths.h>
  31 #endif
  32 #include <pwd.h>
  33 #include <stdarg.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38
  39 #include "xmalloc.h"
  40 #include "key.h"
  41 #include "rsa.h"
  42 #include "authfile.h"
  43 #include "uuencode.h"
  44 #include "buffer.h"
  45 #include "pathnames.h"
  46 #include "log.h"
  47 #include "misc.h"
  48 #include "match.h"
  49 #include "hostfile.h"
  50 #include "dns.h"
  51
  52 #ifdef SMARTCARD
  53 #include "scard.h"
  54 #endif
  55
  56 /* Number of bits in the RSA/DSA key.  This value can be set on the command line. */
  57 #define DEFAULT_BITS            2048
  58 #define DEFAULT_BITS_DSA        1024
  59 u_int32_t bits = 0;
  60
  61 /*
  62  * Flag indicating that we just want to change the passphrase.  This can be
  63  * set on the command line.
  64  */
  65 int change_passphrase = 0;
  66
  67 /*
  68  * Flag indicating that we just want to change the comment.  This can be set
  69  * on the command line.
  70  */
  71 int change_comment = 0;
  72
  73 int quiet = 0;
  74
  75 int log_level = SYSLOG_LEVEL_INFO;
  76
  77 /* Flag indicating that we want to hash a known_hosts file */
  78 int hash_hosts = 0;
  79 /* Flag indicating that we want lookup a host in known_hosts file */
  80 int find_host = 0;
  81 /* Flag indicating that we want to delete a host from a known_hosts file */
  82 int delete_host = 0;
  83
  84 /* Flag indicating that we just want to see the key fingerprint */
  85 int print_fingerprint = 0;
  86 int print_bubblebabble = 0;
  87
  88 /* The identity file name, given on the command line or entered by the user. */
  89 char identity_file[1024];
  90 int have_identity = 0;
  91
  92 /* This is set to the passphrase if given on the command line. */
  93 char *identity_passphrase = NULL;
  94
  95 /* This is set to the new passphrase if given on the command line. */
  96 char *identity_new_passphrase = NULL;
  97
  98 /* This is set to the new comment if given on the command line. */
  99 char *identity_comment = NULL;
 100
 101 /* Dump public key file in format used by real and the original SSH 2 */
 102 int convert_to_ssh2 = 0;
 103 int convert_from_ssh2 = 0;
 104 int print_public = 0;
 105 int print_generic = 0;
 106
 107 char *key_type_name = NULL;
 108
 109 /* argv0 */
 110 extern char *__progname;
 111
 112 char hostname[MAXHOSTNAMELEN];
 113
 114 /* moduli.c */
 115 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
 116 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t);
 117
 118 static void
 119 ask_filename(struct passwd *pw, const char *prompt)
 120 {
 121         char buf[1024];
 122         char *name = NULL;
 123
 124         if (key_type_name == NULL)
 125                 name = _PATH_SSH_CLIENT_ID_RSA;
 126         else {
 127                 switch (key_type_from_name(key_type_name)) {
 128                 case KEY_RSA1:
 129                         name = _PATH_SSH_CLIENT_IDENTITY;
 130                         break;
 131                 case KEY_DSA:
 132                         name = _PATH_SSH_CLIENT_ID_DSA;
 133                         break;
 134                 case KEY_RSA:
 135                         name = _PATH_SSH_CLIENT_ID_RSA;
 136                         break;
 137                 default:
 138                         fprintf(stderr, "bad key type\n");
 139                         exit(1);
 140                         break;
 141                 }
 142         }
 143         snprintf(identity_file, sizeof(identity_file), "%s/%s", pw->pw_dir, name);
 144         fprintf(stderr, "%s (%s): ", prompt, identity_file);
 145         if (fgets(buf, sizeof(buf), stdin) == NULL)
 146                 exit(1);
 147         buf[strcspn(buf, "\n")] = '\0';
 148         if (strcmp(buf, "") != 0)
 149                 strlcpy(identity_file, buf, sizeof(identity_file));
 150         have_identity = 1;
 151 }
 152
 153 static Key *
 154 load_identity(char *filename)
 155 {
 156         char *pass;
 157         Key *prv;
 158
 159         prv = key_load_private(filename, "", NULL);
 160         if (prv == NULL) {
 161                 if (identity_passphrase)
 162                         pass = xstrdup(identity_passphrase);
 163                 else
 164                         pass = read_passphrase("Enter passphrase: ",
 165                             RP_ALLOW_STDIN);
 166                 prv = key_load_private(filename, pass, NULL);
 167                 memset(pass, 0, strlen(pass));
 168                 xfree(pass);
 169         }
 170         return prv;
 171 }
 172
 173 #define SSH_COM_PUBLIC_BEGIN            "---- BEGIN SSH2 PUBLIC KEY ----"
 174 #define SSH_COM_PUBLIC_END              "---- END SSH2 PUBLIC KEY ----"
 175 #define SSH_COM_PRIVATE_BEGIN           "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----"
 176 #define SSH_COM_PRIVATE_KEY_MAGIC       0x3f6ff9eb
 177
 178 static void
 179 do_convert_to_ssh2(struct passwd *pw)
 180 {
 181         Key *k;
 182         u_int len;
 183         u_char *blob;
 184         char comment[61];
 185         struct stat st;
 186
 187         if (!have_identity)
 188                 ask_filename(pw, "Enter file in which the key is");
 189         if (stat(identity_file, &st) < 0) {
 190                 perror(identity_file);
 191                 exit(1);
 192         }
 193         if ((k = key_load_public(identity_file, NULL)) == NULL) {
 194                 if ((k = load_identity(identity_file)) == NULL) {
 195                         fprintf(stderr, "load failed\n");
 196                         exit(1);
 197                 }
 198         }
 199         if (k->type == KEY_RSA1) {
 200                 fprintf(stderr, "version 1 keys are not supported\n");
 201                 exit(1);
 202         }
 203         if (key_to_blob(k, &blob, &len) <= 0) {
 204                 fprintf(stderr, "key_to_blob failed\n");
 205                 exit(1);
 206         }
 207         /* Comment + surrounds must fit into 72 chars (RFC 4716 sec 3.3) */
 208         snprintf(comment, sizeof(comment),
 209             "%u-bit %s, converted by %s@%s from OpenSSH",
 210             key_size(k), key_type(k),
 211             pw->pw_name, hostname);
 212
 213         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_BEGIN);
 214         fprintf(stdout, "Comment: \"%s\"\n", comment);
 215         dump_base64(stdout, blob, len);
 216         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_END);
 217         key_free(k);
 218         xfree(blob);
 219         exit(0);
 220 }
 221
 222 static void
 223 buffer_get_bignum_bits(Buffer *b, BIGNUM *value)
 224 {
 225         u_int bignum_bits = buffer_get_int(b);
 226         u_int bytes = (bignum_bits + 7) / 8;
 227
 228         if (buffer_len(b) < bytes)
 229                 fatal("buffer_get_bignum_bits: input buffer too small: "
 230                     "need %d have %d", bytes, buffer_len(b));
 231         if (BN_bin2bn(buffer_ptr(b), bytes, value) == NULL)
 232                 fatal("buffer_get_bignum_bits: BN_bin2bn failed");
 233         buffer_consume(b, bytes);
 234 }
 235
 236 static Key *
 237 do_convert_private_ssh2_from_blob(u_char *blob, u_int blen)
 238 {
 239         Buffer b;
 240         Key *key = NULL;
 241         char *type, *cipher;
 242         u_char *sig, data[] = "abcde12345";
 243         int magic, rlen, ktype, i1, i2, i3, i4;
 244         u_int slen;
 245         u_long e;
 246
 247         buffer_init(&b);
 248         buffer_append(&b, blob, blen);
 249
 250         magic = buffer_get_int(&b);
 251         if (magic != SSH_COM_PRIVATE_KEY_MAGIC) {
 252                 error("bad magic 0x%x != 0x%x", magic, SSH_COM_PRIVATE_KEY_MAGIC);
 253                 buffer_free(&b);
 254                 return NULL;
 255         }
 256         i1 = buffer_get_int(&b);
 257         type   = buffer_get_string(&b, NULL);
 258         cipher = buffer_get_string(&b, NULL);
 259         i2 = buffer_get_int(&b);
 260         i3 = buffer_get_int(&b);
 261         i4 = buffer_get_int(&b);
 262         debug("ignore (%d %d %d %d)", i1, i2, i3, i4);
 263         if (strcmp(cipher, "none") != 0) {
 264                 error("unsupported cipher %s", cipher);
 265                 xfree(cipher);
 266                 buffer_free(&b);
 267                 xfree(type);
 268                 return NULL;
 269         }
 270         xfree(cipher);
 271
 272         if (strstr(type, "dsa")) {
 273                 ktype = KEY_DSA;
 274         } else if (strstr(type, "rsa")) {
 275                 ktype = KEY_RSA;
 276         } else {
 277                 buffer_free(&b);
 278                 xfree(type);
 279                 return NULL;
 280         }
 281         key = key_new_private(ktype);
 282         xfree(type);
 283
 284         switch (key->type) {
 285         case KEY_DSA:
 286                 buffer_get_bignum_bits(&b, key->dsa->p);
 287                 buffer_get_bignum_bits(&b, key->dsa->g);
 288                 buffer_get_bignum_bits(&b, key->dsa->q);
 289                 buffer_get_bignum_bits(&b, key->dsa->pub_key);
 290                 buffer_get_bignum_bits(&b, key->dsa->priv_key);
 291                 break;
 292         case KEY_RSA:
 293                 e = buffer_get_char(&b);
 294                 debug("e %lx", e);
 295                 if (e < 30) {
 296                         e <<= 8;
 297                         e += buffer_get_char(&b);
 298                         debug("e %lx", e);
 299                         e <<= 8;
 300                         e += buffer_get_char(&b);
 301                         debug("e %lx", e);
 302                 }
 303                 if (!BN_set_word(key->rsa->e, e)) {
 304                         buffer_free(&b);
 305                         key_free(key);
 306                         return NULL;
 307                 }
 308                 buffer_get_bignum_bits(&b, key->rsa->d);
 309                 buffer_get_bignum_bits(&b, key->rsa->n);
 310                 buffer_get_bignum_bits(&b, key->rsa->iqmp);
 311                 buffer_get_bignum_bits(&b, key->rsa->q);
 312                 buffer_get_bignum_bits(&b, key->rsa->p);
 313                 rsa_generate_additional_parameters(key->rsa);
 314                 break;
 315         }
 316         rlen = buffer_len(&b);
 317         if (rlen != 0)
 318                 error("do_convert_private_ssh2_from_blob: "
 319                     "remaining bytes in key blob %d", rlen);
 320         buffer_free(&b);
 321
 322         /* try the key */
 323         key_sign(key, &sig, &slen, data, sizeof(data));
 324         key_verify(key, sig, slen, data, sizeof(data));
 325         xfree(sig);
 326         return key;
 327 }
 328
 329 static int
 330 get_line(FILE *fp, char *line, size_t len)
 331 {
 332         int c;
 333         size_t pos = 0;
 334
 335         line[0] = '\0';
 336         while ((c = fgetc(fp)) != EOF) {
 337                 if (pos >= len - 1) {
 338                         fprintf(stderr, "input line too long.\n");
 339                         exit(1);
 340                 }
 341                 switch (c) {
 342                 case '\r':
 343                         c = fgetc(fp);
 344                         if (c != EOF && c != '\n' && ungetc(c, fp) == EOF) {
 345                                 fprintf(stderr, "unget: %s\n", strerror(errno));
 346                                 exit(1);
 347                         }
 348                         return pos;
 349                 case '\n':
 350                         return pos;
 351                 }
 352                 line[pos++] = c;
 353                 line[pos] = '\0';
 354         }
 355         /* We reached EOF */
 356         return -1;
 357 }
 358
 359 static void
 360 do_convert_from_ssh2(struct passwd *pw)
 361 {
 362         Key *k;
 363         int blen;
 364         u_int len;
 365         char line[1024];
 366         u_char blob[8096];
 367         char encoded[8096];
 368         struct stat st;
 369         int escaped = 0, private = 0, ok;
 370         FILE *fp;
 371
 372         if (!have_identity)
 373                 ask_filename(pw, "Enter file in which the key is");
 374         if (stat(identity_file, &st) < 0) {
 375                 perror(identity_file);
 376                 exit(1);
 377         }
 378         fp = fopen(identity_file, "r");
 379         if (fp == NULL) {
 380                 perror(identity_file);
 381                 exit(1);
 382         }
 383         encoded[0] = '\0';
 384         while ((blen = get_line(fp, line, sizeof(line))) != -1) {
 385                 if (line[blen - 1] == '\\')
 386                         escaped++;
 387                 if (strncmp(line, "----", 4) == 0 ||
 388                     strstr(line, ": ") != NULL) {
 389                         if (strstr(line, SSH_COM_PRIVATE_BEGIN) != NULL)
 390                                 private = 1;
 391                         if (strstr(line, " END ") != NULL) {
 392                                 break;
 393                         }
 394                         /* fprintf(stderr, "ignore: %s", line); */
 395                         continue;
 396                 }
 397                 if (escaped) {
 398                         escaped--;
 399                         /* fprintf(stderr, "escaped: %s", line); */
 400                         continue;
 401                 }
 402                 strlcat(encoded, line, sizeof(encoded));
 403         }
 404         len = strlen(encoded);
 405         if (((len % 4) == 3) &&
 406             (encoded[len-1] == '=') &&
 407             (encoded[len-2] == '=') &&
 408             (encoded[len-3] == '='))
 409                 encoded[len-3] = '\0';
 410         blen = uudecode(encoded, blob, sizeof(blob));
 411         if (blen < 0) {
 412                 fprintf(stderr, "uudecode failed.\n");
 413                 exit(1);
 414         }
 415         k = private ?
 416             do_convert_private_ssh2_from_blob(blob, blen) :
 417             key_from_blob(blob, blen);
 418         if (k == NULL) {
 419                 fprintf(stderr, "decode blob failed.\n");
 420                 exit(1);
 421         }
 422         ok = private ?
 423             (k->type == KEY_DSA ?
 424                  PEM_write_DSAPrivateKey(stdout, k->dsa, NULL, NULL, 0, NULL, NULL) :
 425                  PEM_write_RSAPrivateKey(stdout, k->rsa, NULL, NULL, 0, NULL, NULL)) :
 426             key_write(k, stdout);
 427         if (!ok) {
 428                 fprintf(stderr, "key write failed\n");
 429                 exit(1);
 430         }
 431         key_free(k);
 432         if (!private)
 433                 fprintf(stdout, "\n");
 434         fclose(fp);
 435         exit(0);
 436 }
 437
 438 static void
 439 do_print_public(struct passwd *pw)
 440 {
 441         Key *prv;
 442         struct stat st;
 443
 444         if (!have_identity)
 445                 ask_filename(pw, "Enter file in which the key is");
 446         if (stat(identity_file, &st) < 0) {
 447                 perror(identity_file);
 448                 exit(1);
 449         }
 450         prv = load_identity(identity_file);
 451         if (prv == NULL) {
 452                 fprintf(stderr, "load failed\n");
 453                 exit(1);
 454         }
 455         if (!key_write(prv, stdout))
 456                 fprintf(stderr, "key_write failed");
 457         key_free(prv);
 458         fprintf(stdout, "\n");
 459         exit(0);
 460 }
 461
 462 #ifdef SMARTCARD
 463 static void
 464 do_upload(struct passwd *pw, const char *sc_reader_id)
 465 {
 466         Key *prv = NULL;
 467         struct stat st;
 468         int ret;
 469
 470         if (!have_identity)
 471                 ask_filename(pw, "Enter file in which the key is");
 472         if (stat(identity_file, &st) < 0) {
 473                 perror(identity_file);
 474                 exit(1);
 475         }
 476         prv = load_identity(identity_file);
 477         if (prv == NULL) {
 478                 error("load failed");
 479                 exit(1);
 480         }
 481         ret = sc_put_key(prv, sc_reader_id);
 482         key_free(prv);
 483         if (ret < 0)
 484                 exit(1);
 485         logit("loading key done");
 486         exit(0);
 487 }
 488
 489 static void
 490 do_download(struct passwd *pw, const char *sc_reader_id)
 491 {
 492         Key **keys = NULL;
 493         int i;
 494
 495         keys = sc_get_keys(sc_reader_id, NULL);
 496         if (keys == NULL)
 497                 fatal("cannot read public key from smartcard");
 498         for (i = 0; keys[i]; i++) {
 499                 key_write(keys[i], stdout);
 500                 key_free(keys[i]);
 501                 fprintf(stdout, "\n");
 502         }
 503         xfree(keys);
 504         exit(0);
 505 }
 506 #endif /* SMARTCARD */
 507
 508 static void
 509 do_fingerprint(struct passwd *pw)
 510 {
 511         FILE *f;
 512         Key *public;
 513         char *comment = NULL, *cp, *ep, line[16*1024], *fp, *ra;
 514         int i, skip = 0, num = 0, invalid = 1;
 515         enum fp_rep rep;
 516         enum fp_type fptype;
 517         struct stat st;
 518
 519         fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
 520         rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
 521
 522         if (!have_identity)
 523                 ask_filename(pw, "Enter file in which the key is");
 524         if (stat(identity_file, &st) < 0) {
 525                 perror(identity_file);
 526                 exit(1);
 527         }
 528         public = key_load_public(identity_file, &comment);
 529         if (public != NULL) {
 530                 fp = key_fingerprint(public, fptype, rep);
 531                 ra = key_fingerprint(public, SSH_FP_MD5, SSH_FP_RANDOMART);
 532                 printf("%u %s %s (%s)\n", key_size(public), fp, comment,
 533                     key_type(public));
 534                 if (log_level >= SYSLOG_LEVEL_VERBOSE)
 535                         printf("%s\n", ra);
 536                 key_free(public);
 537                 xfree(comment);
 538                 xfree(ra);
 539                 xfree(fp);
 540                 exit(0);
 541         }
 542         if (comment) {
 543                 xfree(comment);
 544                 comment = NULL;
 545         }
 546
 547         f = fopen(identity_file, "r");
 548         if (f != NULL) {
 549                 while (fgets(line, sizeof(line), f)) {
 550                         if ((cp = strchr(line, '\n')) == NULL) {
 551                                 error("line %d too long: %.40s...",
 552                                     num + 1, line);
 553                                 skip = 1;
 554                                 continue;
 555                         }
 556                         num++;
 557                         if (skip) {
 558                                 skip = 0;
 559                                 continue;
 560                         }
 561                         *cp = '\0';
 562
 563                         /* Skip leading whitespace, empty and comment lines. */
 564                         for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 565                                 ;
 566                         if (!*cp || *cp == '\n' || *cp == '#')
 567                                 continue;
 568                         i = strtol(cp, &ep, 10);
 569                         if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
 570                                 int quoted = 0;
 571                                 comment = cp;
 572                                 for (; *cp && (quoted || (*cp != ' ' &&
 573                                     *cp != '\t')); cp++) {
 574                                         if (*cp == '\\' && cp[1] == '"')
 575                                                 cp++;   /* Skip both */
 576                                         else if (*cp == '"')
 577                                                 quoted = !quoted;
 578                                 }
 579                                 if (!*cp)
 580                                         continue;
 581                                 *cp++ = '\0';
 582                         }
 583                         ep = cp;
 584                         public = key_new(KEY_RSA1);
 585                         if (key_read(public, &cp) != 1) {
 586                                 cp = ep;
 587                                 key_free(public);
 588                                 public = key_new(KEY_UNSPEC);
 589                                 if (key_read(public, &cp) != 1) {
 590                                         key_free(public);
 591                                         continue;
 592                                 }
 593                         }
 594                         comment = *cp ? cp : comment;
 595                         fp = key_fingerprint(public, fptype, rep);
 596                         ra = key_fingerprint(public, SSH_FP_MD5, SSH_FP_RANDOMART);
 597                         printf("%u %s %s (%s)\n", key_size(public), fp,
 598                             comment ? comment : "no comment", key_type(public));
 599                         if (log_level >= SYSLOG_LEVEL_VERBOSE)
 600                                 printf("%s\n", ra);
 601                         xfree(ra);
 602                         xfree(fp);
 603                         key_free(public);
 604                         invalid = 0;
 605                 }
 606                 fclose(f);
 607         }
 608         if (invalid) {
 609                 printf("%s is not a public key file.\n", identity_file);
 610                 exit(1);
 611         }
 612         exit(0);
 613 }
 614
 615 static void
 616 print_host(FILE *f, const char *name, Key *public, int hash)
 617 {
 618         if (print_fingerprint) {
 619                 enum fp_rep rep;
 620                 enum fp_type fptype;
 621                 char *fp, *ra;
 622
 623                 fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
 624                 rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
 625                 fp = key_fingerprint(public, fptype, rep);
 626                 ra = key_fingerprint(public, SSH_FP_MD5, SSH_FP_RANDOMART);
 627                 printf("%u %s %s (%s)\n", key_size(public), fp, name,
 628                     key_type(public));
 629                 if (log_level >= SYSLOG_LEVEL_VERBOSE)
 630                         printf("%s\n", ra);
 631                 xfree(ra);
 632                 xfree(fp);
 633         } else {
 634                 if (hash && (name = host_hash(name, NULL, 0)) == NULL)
 635                         fatal("hash_host failed");
 636                 fprintf(f, "%s ", name);
 637                 if (!key_write(public, f))
 638                         fatal("key_write failed");
 639                 fprintf(f, "\n");
 640         }
 641 }
 642
 643 static void
 644 do_known_hosts(struct passwd *pw, const char *name)
 645 {
 646         FILE *in, *out = stdout;
 647         Key *public;
 648         char *cp, *cp2, *kp, *kp2;
 649         char line[16*1024], tmp[MAXPATHLEN], old[MAXPATHLEN];
 650         int c, skip = 0, inplace = 0, num = 0, invalid = 0, has_unhashed = 0;
 651
 652         if (!have_identity) {
 653                 cp = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
 654                 if (strlcpy(identity_file, cp, sizeof(identity_file)) >=
 655                     sizeof(identity_file))
 656                         fatal("Specified known hosts path too long");
 657                 xfree(cp);
 658                 have_identity = 1;
 659         }
 660         if ((in = fopen(identity_file, "r")) == NULL)
 661                 fatal("fopen: %s", strerror(errno));
 662
 663         /*
 664          * Find hosts goes to stdout, hash and deletions happen in-place
 665          * A corner case is ssh-keygen -HF foo, which should go to stdout
 666          */
 667         if (!find_host && (hash_hosts || delete_host)) {
 668                 if (strlcpy(tmp, identity_file, sizeof(tmp)) >= sizeof(tmp) ||
 669                     strlcat(tmp, ".XXXXXXXXXX", sizeof(tmp)) >= sizeof(tmp) ||
 670                     strlcpy(old, identity_file, sizeof(old)) >= sizeof(old) ||
 671                     strlcat(old, ".old", sizeof(old)) >= sizeof(old))
 672                         fatal("known_hosts path too long");
 673                 umask(077);
 674                 if ((c = mkstemp(tmp)) == -1)
 675                         fatal("mkstemp: %s", strerror(errno));
 676                 if ((out = fdopen(c, "w")) == NULL) {
 677                         c = errno;
 678                         unlink(tmp);
 679                         fatal("fdopen: %s", strerror(c));
 680                 }
 681                 inplace = 1;
 682         }
 683
 684         while (fgets(line, sizeof(line), in)) {
 685                 if ((cp = strchr(line, '\n')) == NULL) {
 686                         error("line %d too long: %.40s...", num + 1, line);
 687                         skip = 1;
 688                         invalid = 1;
 689                         continue;
 690                 }
 691                 num++;
 692                 if (skip) {
 693                         skip = 0;
 694                         continue;
 695                 }
 696                 *cp = '\0';
 697
 698                 /* Skip leading whitespace, empty and comment lines. */
 699                 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 700                         ;
 701                 if (!*cp || *cp == '\n' || *cp == '#') {
 702                         if (inplace)
 703                                 fprintf(out, "%s\n", cp);
 704                         continue;
 705                 }
 706                 /* Find the end of the host name portion. */
 707                 for (kp = cp; *kp && *kp != ' ' && *kp != '\t'; kp++)
 708                         ;
 709                 if (*kp == '\0' || *(kp + 1) == '\0') {
 710                         error("line %d missing key: %.40s...",
 711                             num, line);
 712                         invalid = 1;
 713                         continue;
 714                 }
 715                 *kp++ = '\0';
 716                 kp2 = kp;
 717
 718                 public = key_new(KEY_RSA1);
 719                 if (key_read(public, &kp) != 1) {
 720                         kp = kp2;
 721                         key_free(public);
 722                         public = key_new(KEY_UNSPEC);
 723                         if (key_read(public, &kp) != 1) {
 724                                 error("line %d invalid key: %.40s...",
 725                                     num, line);
 726                                 key_free(public);
 727                                 invalid = 1;
 728                                 continue;
 729                         }
 730                 }
 731
 732                 if (*cp == HASH_DELIM) {
 733                         if (find_host || delete_host) {
 734                                 cp2 = host_hash(name, cp, strlen(cp));
 735                                 if (cp2 == NULL) {
 736                                         error("line %d: invalid hashed "
 737                                             "name: %.64s...", num, line);
 738                                         invalid = 1;
 739                                         continue;
 740                                 }
 741                                 c = (strcmp(cp2, cp) == 0);
 742                                 if (find_host && c) {
 743                                         printf("# Host %s found: "
 744                                             "line %d type %s\n", name,
 745                                             num, key_type(public));
 746                                         print_host(out, cp, public, 0);
 747                                 }
 748                                 if (delete_host && !c)
 749                                         print_host(out, cp, public, 0);
 750                         } else if (hash_hosts)
 751                                 print_host(out, cp, public, 0);
 752                 } else {
 753                         if (find_host || delete_host) {
 754                                 c = (match_hostname(name, cp,
 755                                     strlen(cp)) == 1);
 756                                 if (find_host && c) {
 757                                         printf("# Host %s found: "
 758                                             "line %d type %s\n", name,
 759                                             num, key_type(public));
 760                                         print_host(out, name, public,
 761                                             hash_hosts);
 762                                 }
 763                                 if (delete_host && !c)
 764                                         print_host(out, cp, public, 0);
 765                         } else if (hash_hosts) {
 766                                 for (cp2 = strsep(&cp, ",");
 767                                     cp2 != NULL && *cp2 != '\0';
 768                                     cp2 = strsep(&cp, ",")) {
 769                                         if (strcspn(cp2, "*?!") != strlen(cp2))
 770                                                 fprintf(stderr, "Warning: "
 771                                                     "ignoring host name with "
 772                                                     "metacharacters: %.64s\n",
 773                                                     cp2);
 774                                         else
 775                                                 print_host(out, cp2, public, 1);
 776                                 }
 777                                 has_unhashed = 1;
 778                         }
 779                 }
 780                 key_free(public);
 781         }
 782         fclose(in);
 783
 784         if (invalid) {
 785                 fprintf(stderr, "%s is not a valid known_hosts file.\n",
 786                     identity_file);
 787                 if (inplace) {
 788                         fprintf(stderr, "Not replacing existing known_hosts "
 789                             "file because of errors\n");
 790                         fclose(out);
 791                         unlink(tmp);
 792                 }
 793                 exit(1);
 794         }
 795
 796         if (inplace) {
 797                 fclose(out);
 798
 799                 /* Backup existing file */
 800                 if (unlink(old) == -1 && errno != ENOENT)
 801                         fatal("unlink %.100s: %s", old, strerror(errno));
 802                 if (link(identity_file, old) == -1)
 803                         fatal("link %.100s to %.100s: %s", identity_file, old,
 804                             strerror(errno));
 805                 /* Move new one into place */
 806                 if (rename(tmp, identity_file) == -1) {
 807                         error("rename\"%s\" to \"%s\": %s", tmp, identity_file,
 808                             strerror(errno));
 809                         unlink(tmp);
 810                         unlink(old);
 811                         exit(1);
 812                 }
 813
 814                 fprintf(stderr, "%s updated.\n", identity_file);
 815                 fprintf(stderr, "Original contents retained as %s\n", old);
 816                 if (has_unhashed) {
 817                         fprintf(stderr, "WARNING: %s contains unhashed "
 818                             "entries\n", old);
 819                         fprintf(stderr, "Delete this file to ensure privacy "
 820                             "of hostnames\n");
 821                 }
 822         }
 823
 824         exit(0);
 825 }
 826
 827 /*
 828  * Perform changing a passphrase.  The argument is the passwd structure
 829  * for the current user.
 830  */
 831 static void
 832 do_change_passphrase(struct passwd *pw)
 833 {
 834         char *comment;
 835         char *old_passphrase, *passphrase1, *passphrase2;
 836         struct stat st;
 837         Key *private;
 838
 839         if (!have_identity)
 840                 ask_filename(pw, "Enter file in which the key is");
 841         if (stat(identity_file, &st) < 0) {
 842                 perror(identity_file);
 843                 exit(1);
 844         }
 845         /* Try to load the file with empty passphrase. */
 846         private = key_load_private(identity_file, "", &comment);
 847         if (private == NULL) {
 848                 if (identity_passphrase)
 849                         old_passphrase = xstrdup(identity_passphrase);
 850                 else
 851                         old_passphrase =
 852                             read_passphrase("Enter old passphrase: ",
 853                             RP_ALLOW_STDIN);
 854                 private = key_load_private(identity_file, old_passphrase,
 855                     &comment);
 856                 memset(old_passphrase, 0, strlen(old_passphrase));
 857                 xfree(old_passphrase);
 858                 if (private == NULL) {
 859                         printf("Bad passphrase.\n");
 860                         exit(1);
 861                 }
 862         }
 863         printf("Key has comment '%s'\n", comment);
 864
 865         /* Ask the new passphrase (twice). */
 866         if (identity_new_passphrase) {
 867                 passphrase1 = xstrdup(identity_new_passphrase);
 868                 passphrase2 = NULL;
 869         } else {
 870                 passphrase1 =
 871                         read_passphrase("Enter new passphrase (empty for no "
 872                             "passphrase): ", RP_ALLOW_STDIN);
 873                 passphrase2 = read_passphrase("Enter same passphrase again: ",
 874                     RP_ALLOW_STDIN);
 875
 876                 /* Verify that they are the same. */
 877                 if (strcmp(passphrase1, passphrase2) != 0) {
 878                         memset(passphrase1, 0, strlen(passphrase1));
 879                         memset(passphrase2, 0, strlen(passphrase2));
 880                         xfree(passphrase1);
 881                         xfree(passphrase2);
 882                         printf("Pass phrases do not match.  Try again.\n");
 883                         exit(1);
 884                 }
 885                 /* Destroy the other copy. */
 886                 memset(passphrase2, 0, strlen(passphrase2));
 887                 xfree(passphrase2);
 888         }
 889
 890         /* Save the file using the new passphrase. */
 891         if (!key_save_private(private, identity_file, passphrase1, comment)) {
 892                 printf("Saving the key failed: %s.\n", identity_file);
 893                 memset(passphrase1, 0, strlen(passphrase1));
 894                 xfree(passphrase1);
 895                 key_free(private);
 896                 xfree(comment);
 897                 exit(1);
 898         }
 899         /* Destroy the passphrase and the copy of the key in memory. */
 900         memset(passphrase1, 0, strlen(passphrase1));
 901         xfree(passphrase1);
 902         key_free(private);               /* Destroys contents */
 903         xfree(comment);
 904
 905         printf("Your identification has been saved with the new passphrase.\n");
 906         exit(0);
 907 }
 908
 909 /*
 910  * Print the SSHFP RR.
 911  */
 912 static int
 913 do_print_resource_record(struct passwd *pw, char *fname, char *hname)
 914 {
 915         Key *public;
 916         char *comment = NULL;
 917         struct stat st;
 918
 919         if (fname == NULL)
 920                 ask_filename(pw, "Enter file in which the key is");
 921         if (stat(fname, &st) < 0) {
 922                 if (errno == ENOENT)
 923                         return 0;
 924                 perror(fname);
 925                 exit(1);
 926         }
 927         public = key_load_public(fname, &comment);
 928         if (public != NULL) {
 929                 export_dns_rr(hname, public, stdout, print_generic);
 930                 key_free(public);
 931                 xfree(comment);
 932                 return 1;
 933         }
 934         if (comment)
 935                 xfree(comment);
 936
 937         printf("failed to read v2 public key from %s.\n", fname);
 938         exit(1);
 939 }
 940
 941 /*
 942  * Change the comment of a private key file.
 943  */
 944 static void
 945 do_change_comment(struct passwd *pw)
 946 {
 947         char new_comment[1024], *comment, *passphrase;
 948         Key *private;
 949         Key *public;
 950         struct stat st;
 951         FILE *f;
 952         int fd;
 953
 954         if (!have_identity)
 955                 ask_filename(pw, "Enter file in which the key is");
 956         if (stat(identity_file, &st) < 0) {
 957                 perror(identity_file);
 958                 exit(1);
 959         }
 960         private = key_load_private(identity_file, "", &comment);
 961         if (private == NULL) {
 962                 if (identity_passphrase)
 963                         passphrase = xstrdup(identity_passphrase);
 964                 else if (identity_new_passphrase)
 965                         passphrase = xstrdup(identity_new_passphrase);
 966                 else
 967                         passphrase = read_passphrase("Enter passphrase: ",
 968                             RP_ALLOW_STDIN);
 969                 /* Try to load using the passphrase. */
 970                 private = key_load_private(identity_file, passphrase, &comment);
 971                 if (private == NULL) {
 972                         memset(passphrase, 0, strlen(passphrase));
 973                         xfree(passphrase);
 974                         printf("Bad passphrase.\n");
 975                         exit(1);
 976                 }
 977         } else {
 978                 passphrase = xstrdup("");
 979         }
 980         if (private->type != KEY_RSA1) {
 981                 fprintf(stderr, "Comments are only supported for RSA1 keys.\n");
 982                 key_free(private);
 983                 exit(1);
 984         }
 985         printf("Key now has comment '%s'\n", comment);
 986
 987         if (identity_comment) {
 988                 strlcpy(new_comment, identity_comment, sizeof(new_comment));
 989         } else {
 990                 printf("Enter new comment: ");
 991                 fflush(stdout);
 992                 if (!fgets(new_comment, sizeof(new_comment), stdin)) {
 993                         memset(passphrase, 0, strlen(passphrase));
 994                         key_free(private);
 995                         exit(1);
 996                 }
 997                 new_comment[strcspn(new_comment, "\n")] = '\0';
 998         }
 999
1000         /* Save the file using the new passphrase. */
1001         if (!key_save_private(private, identity_file, passphrase, new_comment)) {
1002                 printf("Saving the key failed: %s.\n", identity_file);
1003                 memset(passphrase, 0, strlen(passphrase));
1004                 xfree(passphrase);
1005                 key_free(private);
1006                 xfree(comment);
1007                 exit(1);
1008         }
1009         memset(passphrase, 0, strlen(passphrase));
1010         xfree(passphrase);
1011         public = key_from_private(private);
1012         key_free(private);
1013
1014         strlcat(identity_file, ".pub", sizeof(identity_file));
1015         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
1016         if (fd == -1) {
1017                 printf("Could not save your public key in %s\n", identity_file);
1018                 exit(1);
1019         }
1020         f = fdopen(fd, "w");
1021         if (f == NULL) {
1022                 printf("fdopen %s failed\n", identity_file);
1023                 exit(1);
1024         }
1025         if (!key_write(public, f))
1026                 fprintf(stderr, "write key failed\n");
1027         key_free(public);
1028         fprintf(f, " %s\n", new_comment);
1029         fclose(f);
1030
1031         xfree(comment);
1032
1033         printf("The comment in your key file has been changed.\n");
1034         exit(0);
1035 }
1036
1037 static void
1038 usage(void)
1039 {
1040         fprintf(stderr, "usage: %s [options]\n", __progname);
1041         fprintf(stderr, "Options:\n");
1042         fprintf(stderr, "  -a trials   Number of trials for screening DH-GEX moduli.\n");
1043         fprintf(stderr, "  -B          Show bubblebabble digest of key file.\n");
1044         fprintf(stderr, "  -b bits     Number of bits in the key to create.\n");
1045         fprintf(stderr, "  -C comment  Provide new comment.\n");
1046         fprintf(stderr, "  -c          Change comment in private and public key files.\n");
1047 #ifdef SMARTCARD
1048         fprintf(stderr, "  -D reader   Download public key from smartcard.\n");
1049 #endif /* SMARTCARD */
1050         fprintf(stderr, "  -e          Convert OpenSSH to RFC 4716 key file.\n");
1051         fprintf(stderr, "  -F hostname Find hostname in known hosts file.\n");
1052         fprintf(stderr, "  -f filename Filename of the key file.\n");
1053         fprintf(stderr, "  -G file     Generate candidates for DH-GEX moduli.\n");
1054         fprintf(stderr, "  -g          Use generic DNS resource record format.\n");
1055         fprintf(stderr, "  -H          Hash names in known_hosts file.\n");
1056         fprintf(stderr, "  -i          Convert RFC 4716 to OpenSSH key file.\n");
1057         fprintf(stderr, "  -l          Show fingerprint of key file.\n");
1058         fprintf(stderr, "  -M memory   Amount of memory (MB) to use for generating DH-GEX moduli.\n");
1059         fprintf(stderr, "  -N phrase   Provide new passphrase.\n");
1060         fprintf(stderr, "  -P phrase   Provide old passphrase.\n");
1061         fprintf(stderr, "  -p          Change passphrase of private key file.\n");
1062         fprintf(stderr, "  -q          Quiet.\n");
1063         fprintf(stderr, "  -R hostname Remove host from known_hosts file.\n");
1064         fprintf(stderr, "  -r hostname Print DNS resource record.\n");
1065         fprintf(stderr, "  -S start    Start point (hex) for generating DH-GEX moduli.\n");
1066         fprintf(stderr, "  -T file     Screen candidates for DH-GEX moduli.\n");
1067         fprintf(stderr, "  -t type     Specify type of key to create.\n");
1068 #ifdef SMARTCARD
1069         fprintf(stderr, "  -U reader   Upload private key to smartcard.\n");
1070 #endif /* SMARTCARD */
1071         fprintf(stderr, "  -v          Verbose.\n");
1072         fprintf(stderr, "  -W gen      Generator to use for generating DH-GEX moduli.\n");
1073         fprintf(stderr, "  -y          Read private key file and print public key.\n");
1074
1075         exit(1);
1076 }
1077
1078 /*
1079  * Main program for key management.
1080  */
1081 int
1082 main(int argc, char **argv)
1083 {
1084         char dotsshdir[MAXPATHLEN], comment[1024], *passphrase1, *passphrase2;
1085         char out_file[MAXPATHLEN], *reader_id = NULL;
1086         char *rr_hostname = NULL;
1087         Key *private, *public;
1088         struct passwd *pw;
1089         struct stat st;
1090         int opt, type, fd, download = 0;
1091         u_int32_t memory = 0, generator_wanted = 0, trials = 100;
1092         int do_gen_candidates = 0, do_screen_candidates = 0;
1093         BIGNUM *start = NULL;
1094         FILE *f;
1095         const char *errstr;
1096
1097         extern int optind;
1098         extern char *optarg;
1099
1100         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1101         sanitise_stdfd();
1102
1103         __progname = ssh_get_progname(argv[0]);
1104
1105         SSLeay_add_all_algorithms();
1106         log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
1107
1108         init_rng();
1109         seed_rng();
1110
1111         /* we need this for the home * directory.  */
1112         pw = getpwuid(getuid());
1113         if (!pw) {
1114                 printf("You don't exist, go away!\n");
1115                 exit(1);
1116         }
1117         if (gethostname(hostname, sizeof(hostname)) < 0) {
1118                 perror("gethostname");
1119                 exit(1);
1120         }
1121
1122         while ((opt = getopt(argc, argv,
1123             "degiqpclBHvxXyF:b:f:t:U:D:P:N:C:r:g:R:T:G:M:S:a:W:")) != -1) {
1124                 switch (opt) {
1125                 case 'b':
1126                         bits = (u_int32_t)strtonum(optarg, 768, 32768, &errstr);
1127                         if (errstr)
1128                                 fatal("Bits has bad value %s (%s)",
1129                                         optarg, errstr);
1130                         break;
1131                 case 'F':
1132                         find_host = 1;
1133                         rr_hostname = optarg;
1134                         break;
1135                 case 'H':
1136                         hash_hosts = 1;
1137                         break;
1138                 case 'R':
1139                         delete_host = 1;
1140                         rr_hostname = optarg;
1141                         break;
1142                 case 'l':
1143                         print_fingerprint = 1;
1144                         break;
1145                 case 'B':
1146                         print_bubblebabble = 1;
1147                         break;
1148                 case 'p':
1149                         change_passphrase = 1;
1150                         break;
1151                 case 'c':
1152                         change_comment = 1;
1153                         break;
1154                 case 'f':
1155                         if (strlcpy(identity_file, optarg, sizeof(identity_file)) >=
1156                             sizeof(identity_file))
1157                                 fatal("Identity filename too long");
1158                         have_identity = 1;
1159                         break;
1160                 case 'g':
1161                         print_generic = 1;
1162                         break;
1163                 case 'P':
1164                         identity_passphrase = optarg;
1165                         break;
1166                 case 'N':
1167                         identity_new_passphrase = optarg;
1168                         break;
1169                 case 'C':
1170                         identity_comment = optarg;
1171                         break;
1172                 case 'q':
1173                         quiet = 1;
1174                         break;
1175                 case 'e':
1176                 case 'x':
1177                         /* export key */
1178                         convert_to_ssh2 = 1;
1179                         break;
1180                 case 'i':
1181                 case 'X':
1182                         /* import key */
1183                         convert_from_ssh2 = 1;
1184                         break;
1185                 case 'y':
1186                         print_public = 1;
1187                         break;
1188                 case 'd':
1189                         key_type_name = "dsa";
1190                         break;
1191                 case 't':
1192                         key_type_name = optarg;
1193                         break;
1194                 case 'D':
1195                         download = 1;
1196                         /*FALLTHROUGH*/
1197                 case 'U':
1198                         reader_id = optarg;
1199                         break;
1200                 case 'v':
1201                         if (log_level == SYSLOG_LEVEL_INFO)
1202                                 log_level = SYSLOG_LEVEL_DEBUG1;
1203                         else {
1204                                 if (log_level >= SYSLOG_LEVEL_DEBUG1 &&
1205                                     log_level < SYSLOG_LEVEL_DEBUG3)
1206                                         log_level++;
1207                         }
1208                         break;
1209                 case 'r':
1210                         rr_hostname = optarg;
1211                         break;
1212                 case 'W':
1213                         generator_wanted = (u_int32_t)strtonum(optarg, 1,
1214                             UINT_MAX, &errstr);
1215                         if (errstr)
1216                                 fatal("Desired generator has bad value: %s (%s)",
1217                                         optarg, errstr);
1218                         break;
1219                 case 'a':
1220                         trials = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1221                         if (errstr)
1222                                 fatal("Invalid number of trials: %s (%s)",
1223                                         optarg, errstr);
1224                         break;
1225                 case 'M':
1226                         memory = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1227                         if (errstr) {
1228                                 fatal("Memory limit is %s: %s", errstr, optarg);
1229                         }
1230                         break;
1231                 case 'G':
1232                         do_gen_candidates = 1;
1233                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1234                             sizeof(out_file))
1235                                 fatal("Output filename too long");
1236                         break;
1237                 case 'T':
1238                         do_screen_candidates = 1;
1239                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1240                             sizeof(out_file))
1241                                 fatal("Output filename too long");
1242                         break;
1243                 case 'S':
1244                         /* XXX - also compare length against bits */
1245                         if (BN_hex2bn(&start, optarg) == 0)
1246                                 fatal("Invalid start point.");
1247                         break;
1248                 case '?':
1249                 default:
1250                         usage();
1251                 }
1252         }
1253
1254         /* reinit */
1255         log_init(argv[0], log_level, SYSLOG_FACILITY_USER, 1);
1256
1257         if (optind < argc) {
1258                 printf("Too many arguments.\n");
1259                 usage();
1260         }
1261         if (change_passphrase && change_comment) {
1262                 printf("Can only have one of -p and -c.\n");
1263                 usage();
1264         }
1265         if (print_fingerprint && (delete_host || hash_hosts)) {
1266                 printf("Cannot use -l with -D or -R.\n");
1267                 usage();
1268         }
1269         if (delete_host || hash_hosts || find_host)
1270                 do_known_hosts(pw, rr_hostname);
1271         if (print_fingerprint || print_bubblebabble)
1272                 do_fingerprint(pw);
1273         if (change_passphrase)
1274                 do_change_passphrase(pw);
1275         if (change_comment)
1276                 do_change_comment(pw);
1277         if (convert_to_ssh2)
1278                 do_convert_to_ssh2(pw);
1279         if (convert_from_ssh2)
1280                 do_convert_from_ssh2(pw);
1281         if (print_public)
1282                 do_print_public(pw);
1283         if (rr_hostname != NULL) {
1284                 unsigned int n = 0;
1285
1286                 if (have_identity) {
1287                         n = do_print_resource_record(pw,
1288                             identity_file, rr_hostname);
1289                         if (n == 0) {
1290                                 perror(identity_file);
1291                                 exit(1);
1292                         }
1293                         exit(0);
1294                 } else {
1295
1296                         n += do_print_resource_record(pw,
1297                             _PATH_HOST_RSA_KEY_FILE, rr_hostname);
1298                         n += do_print_resource_record(pw,
1299                             _PATH_HOST_DSA_KEY_FILE, rr_hostname);
1300
1301                         if (n == 0)
1302                                 fatal("no keys found.");
1303                         exit(0);
1304                 }
1305         }
1306         if (reader_id != NULL) {
1307 #ifdef SMARTCARD
1308                 if (download)
1309                         do_download(pw, reader_id);
1310                 else
1311                         do_upload(pw, reader_id);
1312 #else /* SMARTCARD */
1313                 fatal("no support for smartcards.");
1314 #endif /* SMARTCARD */
1315         }
1316
1317         if (do_gen_candidates) {
1318                 FILE *out = fopen(out_file, "w");
1319
1320                 if (out == NULL) {
1321                         error("Couldn't open modulus candidate file \"%s\": %s",
1322                             out_file, strerror(errno));
1323                         return (1);
1324                 }
1325                 if (bits == 0)
1326                         bits = DEFAULT_BITS;
1327                 if (gen_candidates(out, memory, bits, start) != 0)
1328                         fatal("modulus candidate generation failed");
1329
1330                 return (0);
1331         }
1332
1333         if (do_screen_candidates) {
1334                 FILE *in;
1335                 FILE *out = fopen(out_file, "w");
1336
1337                 if (have_identity && strcmp(identity_file, "-") != 0) {
1338                         if ((in = fopen(identity_file, "r")) == NULL) {
1339                                 fatal("Couldn't open modulus candidate "
1340                                     "file \"%s\": %s", identity_file,
1341                                     strerror(errno));
1342                         }
1343                 } else
1344                         in = stdin;
1345
1346                 if (out == NULL) {
1347                         fatal("Couldn't open moduli file \"%s\": %s",
1348                             out_file, strerror(errno));
1349                 }
1350                 if (prime_test(in, out, trials, generator_wanted) != 0)
1351                         fatal("modulus screening failed");
1352                 return (0);
1353         }
1354
1355         arc4random_stir();
1356
1357         if (key_type_name == NULL)
1358                 key_type_name = "rsa";
1359
1360         type = key_type_from_name(key_type_name);
1361         if (type == KEY_UNSPEC) {
1362                 fprintf(stderr, "unknown key type %s\n", key_type_name);
1363                 exit(1);
1364         }
1365         if (bits == 0)
1366                 bits = (type == KEY_DSA) ? DEFAULT_BITS_DSA : DEFAULT_BITS;
1367         if (type == KEY_DSA && bits != 1024)
1368                 fatal("DSA keys must be 1024 bits");
1369         if (!quiet)
1370                 printf("Generating public/private %s key pair.\n", key_type_name);
1371         private = key_generate(type, bits);
1372         if (private == NULL) {
1373                 fprintf(stderr, "key_generate failed\n");
1374                 exit(1);
1375         }
1376         public  = key_from_private(private);
1377
1378         if (!have_identity)
1379                 ask_filename(pw, "Enter file in which to save the key");
1380
1381         /* Create ~/.ssh directory if it doesn't already exist. */
1382         snprintf(dotsshdir, sizeof dotsshdir, "%s/%s", pw->pw_dir, _PATH_SSH_USER_DIR);
1383         if (strstr(identity_file, dotsshdir) != NULL &&
1384             stat(dotsshdir, &st) < 0) {
1385                 if (mkdir(dotsshdir, 0700) < 0)
1386                         error("Could not create directory '%s'.", dotsshdir);
1387                 else if (!quiet)
1388                         printf("Created directory '%s'.\n", dotsshdir);
1389         }
1390         /* If the file already exists, ask the user to confirm. */
1391         if (stat(identity_file, &st) >= 0) {
1392                 char yesno[3];
1393                 printf("%s already exists.\n", identity_file);
1394                 printf("Overwrite (y/n)? ");
1395                 fflush(stdout);
1396                 if (fgets(yesno, sizeof(yesno), stdin) == NULL)
1397                         exit(1);
1398                 if (yesno[0] != 'y' && yesno[0] != 'Y')
1399                         exit(1);
1400         }
1401         /* Ask for a passphrase (twice). */
1402         if (identity_passphrase)
1403                 passphrase1 = xstrdup(identity_passphrase);
1404         else if (identity_new_passphrase)
1405                 passphrase1 = xstrdup(identity_new_passphrase);
1406         else {
1407 passphrase_again:
1408                 passphrase1 =
1409                         read_passphrase("Enter passphrase (empty for no "
1410                             "passphrase): ", RP_ALLOW_STDIN);
1411                 passphrase2 = read_passphrase("Enter same passphrase again: ",
1412                     RP_ALLOW_STDIN);
1413                 if (strcmp(passphrase1, passphrase2) != 0) {
1414                         /*
1415                          * The passphrases do not match.  Clear them and
1416                          * retry.
1417                          */
1418                         memset(passphrase1, 0, strlen(passphrase1));
1419                         memset(passphrase2, 0, strlen(passphrase2));
1420                         xfree(passphrase1);
1421                         xfree(passphrase2);
1422                         printf("Passphrases do not match.  Try again.\n");
1423                         goto passphrase_again;
1424                 }
1425                 /* Clear the other copy of the passphrase. */
1426                 memset(passphrase2, 0, strlen(passphrase2));
1427                 xfree(passphrase2);
1428         }
1429
1430         if (identity_comment) {
1431                 strlcpy(comment, identity_comment, sizeof(comment));
1432         } else {
1433                 /* Create default comment field for the passphrase. */
1434                 snprintf(comment, sizeof comment, "%s@%s", pw->pw_name, hostname);
1435         }
1436
1437         /* Save the key with the given passphrase and comment. */
1438         if (!key_save_private(private, identity_file, passphrase1, comment)) {
1439                 printf("Saving the key failed: %s.\n", identity_file);
1440                 memset(passphrase1, 0, strlen(passphrase1));
1441                 xfree(passphrase1);
1442                 exit(1);
1443         }
1444         /* Clear the passphrase. */
1445         memset(passphrase1, 0, strlen(passphrase1));
1446         xfree(passphrase1);
1447
1448         /* Clear the private key and the random number generator. */
1449         key_free(private);
1450         arc4random_stir();
1451
1452         if (!quiet)
1453                 printf("Your identification has been saved in %s.\n", identity_file);
1454
1455         strlcat(identity_file, ".pub", sizeof(identity_file));
1456         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
1457         if (fd == -1) {
1458                 printf("Could not save your public key in %s\n", identity_file);
1459                 exit(1);
1460         }
1461         f = fdopen(fd, "w");
1462         if (f == NULL) {
1463                 printf("fdopen %s failed\n", identity_file);
1464                 exit(1);
1465         }
1466         if (!key_write(public, f))
1467                 fprintf(stderr, "write key failed\n");
1468         fprintf(f, " %s\n", comment);
1469         fclose(f);
1470
1471         if (!quiet) {
1472                 char *fp = key_fingerprint(public, SSH_FP_MD5, SSH_FP_HEX);
1473                 char *ra = key_fingerprint(public, SSH_FP_MD5,
1474                     SSH_FP_RANDOMART);
1475                 printf("Your public key has been saved in %s.\n",
1476                     identity_file);
1477                 printf("The key fingerprint is:\n");
1478                 printf("%s %s\n", fp, comment);
1479                 printf("The key's randomart image is:\n");
1480                 printf("%s\n", ra);
1481                 xfree(ra);
1482                 xfree(fp);
1483         }
1484
1485         key_free(public);
1486         exit(0);
1487 }