ssh-keygen.c

   1 /* $OpenBSD: ssh-keygen.c,v 1.146 2006/07/06 16:22:39 stevesk 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/stat.h>
  19
  20 #include <openssl/evp.h>
  21 #include <openssl/pem.h>
  22
  23 #include <paths.h>
  24 #include <pwd.h>
  25
  26 #include "xmalloc.h"
  27 #include "key.h"
  28 #include "rsa.h"
  29 #include "authfile.h"
  30 #include "uuencode.h"
  31 #include "buffer.h"
  32 #include "bufaux.h"
  33 #include "pathnames.h"
  34 #include "log.h"
  35 #include "misc.h"
  36 #include "match.h"
  37 #include "hostfile.h"
  38 #include "dns.h"
  39
  40 #ifdef SMARTCARD
  41 #include "scard.h"
  42 #endif
  43
  44 /* Number of bits in the RSA/DSA key.  This value can be set on the command line. */
  45 #define DEFAULT_BITS            2048
  46 #define DEFAULT_BITS_DSA        1024
  47 u_int32_t bits = 0;
  48
  49 /*
  50  * Flag indicating that we just want to change the passphrase.  This can be
  51  * set on the command line.
  52  */
  53 int change_passphrase = 0;
  54
  55 /*
  56  * Flag indicating that we just want to change the comment.  This can be set
  57  * on the command line.
  58  */
  59 int change_comment = 0;
  60
  61 int quiet = 0;
  62
  63 /* Flag indicating that we want to hash a known_hosts file */
  64 int hash_hosts = 0;
  65 /* Flag indicating that we want lookup a host in known_hosts file */
  66 int find_host = 0;
  67 /* Flag indicating that we want to delete a host from a known_hosts file */
  68 int delete_host = 0;
  69
  70 /* Flag indicating that we just want to see the key fingerprint */
  71 int print_fingerprint = 0;
  72 int print_bubblebabble = 0;
  73
  74 /* The identity file name, given on the command line or entered by the user. */
  75 char identity_file[1024];
  76 int have_identity = 0;
  77
  78 /* This is set to the passphrase if given on the command line. */
  79 char *identity_passphrase = NULL;
  80
  81 /* This is set to the new passphrase if given on the command line. */
  82 char *identity_new_passphrase = NULL;
  83
  84 /* This is set to the new comment if given on the command line. */
  85 char *identity_comment = NULL;
  86
  87 /* Dump public key file in format used by real and the original SSH 2 */
  88 int convert_to_ssh2 = 0;
  89 int convert_from_ssh2 = 0;
  90 int print_public = 0;
  91 int print_generic = 0;
  92
  93 char *key_type_name = NULL;
  94
  95 /* argv0 */
  96 extern char *__progname;
  97
  98 char hostname[MAXHOSTNAMELEN];
  99
 100 /* moduli.c */
 101 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
 102 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t);
 103
 104 static void
 105 ask_filename(struct passwd *pw, const char *prompt)
 106 {
 107         char buf[1024];
 108         char *name = NULL;
 109
 110         if (key_type_name == NULL)
 111                 name = _PATH_SSH_CLIENT_ID_RSA;
 112         else {
 113                 switch (key_type_from_name(key_type_name)) {
 114                 case KEY_RSA1:
 115                         name = _PATH_SSH_CLIENT_IDENTITY;
 116                         break;
 117                 case KEY_DSA:
 118                         name = _PATH_SSH_CLIENT_ID_DSA;
 119                         break;
 120                 case KEY_RSA:
 121                         name = _PATH_SSH_CLIENT_ID_RSA;
 122                         break;
 123                 default:
 124                         fprintf(stderr, "bad key type");
 125                         exit(1);
 126                         break;
 127                 }
 128         }
 129         snprintf(identity_file, sizeof(identity_file), "%s/%s", pw->pw_dir, name);
 130         fprintf(stderr, "%s (%s): ", prompt, identity_file);
 131         if (fgets(buf, sizeof(buf), stdin) == NULL)
 132                 exit(1);
 133         if (strchr(buf, '\n'))
 134                 *strchr(buf, '\n') = 0;
 135         if (strcmp(buf, "") != 0)
 136                 strlcpy(identity_file, buf, sizeof(identity_file));
 137         have_identity = 1;
 138 }
 139
 140 static Key *
 141 load_identity(char *filename)
 142 {
 143         char *pass;
 144         Key *prv;
 145
 146         prv = key_load_private(filename, "", NULL);
 147         if (prv == NULL) {
 148                 if (identity_passphrase)
 149                         pass = xstrdup(identity_passphrase);
 150                 else
 151                         pass = read_passphrase("Enter passphrase: ",
 152                             RP_ALLOW_STDIN);
 153                 prv = key_load_private(filename, pass, NULL);
 154                 memset(pass, 0, strlen(pass));
 155                 xfree(pass);
 156         }
 157         return prv;
 158 }
 159
 160 #define SSH_COM_PUBLIC_BEGIN            "---- BEGIN SSH2 PUBLIC KEY ----"
 161 #define SSH_COM_PUBLIC_END              "---- END SSH2 PUBLIC KEY ----"
 162 #define SSH_COM_PRIVATE_BEGIN           "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----"
 163 #define SSH_COM_PRIVATE_KEY_MAGIC       0x3f6ff9eb
 164
 165 static void
 166 do_convert_to_ssh2(struct passwd *pw)
 167 {
 168         Key *k;
 169         u_int len;
 170         u_char *blob;
 171         struct stat st;
 172
 173         if (!have_identity)
 174                 ask_filename(pw, "Enter file in which the key is");
 175         if (stat(identity_file, &st) < 0) {
 176                 perror(identity_file);
 177                 exit(1);
 178         }
 179         if ((k = key_load_public(identity_file, NULL)) == NULL) {
 180                 if ((k = load_identity(identity_file)) == NULL) {
 181                         fprintf(stderr, "load failed\n");
 182                         exit(1);
 183                 }
 184         }
 185         if (k->type == KEY_RSA1) {
 186                 fprintf(stderr, "version 1 keys are not supported\n");
 187                 exit(1);
 188         }
 189         if (key_to_blob(k, &blob, &len) <= 0) {
 190                 fprintf(stderr, "key_to_blob failed\n");
 191                 exit(1);
 192         }
 193         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_BEGIN);
 194         fprintf(stdout,
 195             "Comment: \"%u-bit %s, converted from OpenSSH by %s@%s\"\n",
 196             key_size(k), key_type(k),
 197             pw->pw_name, hostname);
 198         dump_base64(stdout, blob, len);
 199         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_END);
 200         key_free(k);
 201         xfree(blob);
 202         exit(0);
 203 }
 204
 205 static void
 206 buffer_get_bignum_bits(Buffer *b, BIGNUM *value)
 207 {
 208         u_int bignum_bits = buffer_get_int(b);
 209         u_int bytes = (bignum_bits + 7) / 8;
 210
 211         if (buffer_len(b) < bytes)
 212                 fatal("buffer_get_bignum_bits: input buffer too small: "
 213                     "need %d have %d", bytes, buffer_len(b));
 214         BN_bin2bn(buffer_ptr(b), bytes, value);
 215         buffer_consume(b, bytes);
 216 }
 217
 218 static Key *
 219 do_convert_private_ssh2_from_blob(u_char *blob, u_int blen)
 220 {
 221         Buffer b;
 222         Key *key = NULL;
 223         char *type, *cipher;
 224         u_char *sig, data[] = "abcde12345";
 225         int magic, rlen, ktype, i1, i2, i3, i4;
 226         u_int slen;
 227         u_long e;
 228
 229         buffer_init(&b);
 230         buffer_append(&b, blob, blen);
 231
 232         magic  = buffer_get_int(&b);
 233         if (magic != SSH_COM_PRIVATE_KEY_MAGIC) {
 234                 error("bad magic 0x%x != 0x%x", magic, SSH_COM_PRIVATE_KEY_MAGIC);
 235                 buffer_free(&b);
 236                 return NULL;
 237         }
 238         i1 = buffer_get_int(&b);
 239         type   = buffer_get_string(&b, NULL);
 240         cipher = buffer_get_string(&b, NULL);
 241         i2 = buffer_get_int(&b);
 242         i3 = buffer_get_int(&b);
 243         i4 = buffer_get_int(&b);
 244         debug("ignore (%d %d %d %d)", i1,i2,i3,i4);
 245         if (strcmp(cipher, "none") != 0) {
 246                 error("unsupported cipher %s", cipher);
 247                 xfree(cipher);
 248                 buffer_free(&b);
 249                 xfree(type);
 250                 return NULL;
 251         }
 252         xfree(cipher);
 253
 254         if (strstr(type, "dsa")) {
 255                 ktype = KEY_DSA;
 256         } else if (strstr(type, "rsa")) {
 257                 ktype = KEY_RSA;
 258         } else {
 259                 buffer_free(&b);
 260                 xfree(type);
 261                 return NULL;
 262         }
 263         key = key_new_private(ktype);
 264         xfree(type);
 265
 266         switch (key->type) {
 267         case KEY_DSA:
 268                 buffer_get_bignum_bits(&b, key->dsa->p);
 269                 buffer_get_bignum_bits(&b, key->dsa->g);
 270                 buffer_get_bignum_bits(&b, key->dsa->q);
 271                 buffer_get_bignum_bits(&b, key->dsa->pub_key);
 272                 buffer_get_bignum_bits(&b, key->dsa->priv_key);
 273                 break;
 274         case KEY_RSA:
 275                 e  = buffer_get_char(&b);
 276                 debug("e %lx", e);
 277                 if (e < 30) {
 278                         e <<= 8;
 279                         e += buffer_get_char(&b);
 280                         debug("e %lx", e);
 281                         e <<= 8;
 282                         e += buffer_get_char(&b);
 283                         debug("e %lx", e);
 284                 }
 285                 if (!BN_set_word(key->rsa->e, e)) {
 286                         buffer_free(&b);
 287                         key_free(key);
 288                         return NULL;
 289                 }
 290                 buffer_get_bignum_bits(&b, key->rsa->d);
 291                 buffer_get_bignum_bits(&b, key->rsa->n);
 292                 buffer_get_bignum_bits(&b, key->rsa->iqmp);
 293                 buffer_get_bignum_bits(&b, key->rsa->q);
 294                 buffer_get_bignum_bits(&b, key->rsa->p);
 295                 rsa_generate_additional_parameters(key->rsa);
 296                 break;
 297         }
 298         rlen = buffer_len(&b);
 299         if (rlen != 0)
 300                 error("do_convert_private_ssh2_from_blob: "
 301                     "remaining bytes in key blob %d", rlen);
 302         buffer_free(&b);
 303
 304         /* try the key */
 305         key_sign(key, &sig, &slen, data, sizeof(data));
 306         key_verify(key, sig, slen, data, sizeof(data));
 307         xfree(sig);
 308         return key;
 309 }
 310
 311 static int
 312 get_line(FILE *fp, char *line, size_t len)
 313 {
 314         int c;
 315         size_t pos = 0;
 316
 317         line[0] = '\0';
 318         while ((c = fgetc(fp)) != EOF) {
 319                 if (pos >= len - 1) {
 320                         fprintf(stderr, "input line too long.\n");
 321                         exit(1);
 322                 }
 323                 switch (c) {
 324                 case '\r':
 325                         c = fgetc(fp);
 326                         if (c != EOF && c != '\n' && ungetc(c, fp) == EOF) {
 327                                 fprintf(stderr, "unget: %s\n", strerror(errno));
 328                                 exit(1);
 329                         }
 330                         return pos;
 331                 case '\n':
 332                         return pos;
 333                 }
 334                 line[pos++] = c;
 335                 line[pos] = '\0';
 336         }
 337         if (c == EOF)
 338                 return -1;
 339         return pos;
 340 }
 341
 342 static void
 343 do_convert_from_ssh2(struct passwd *pw)
 344 {
 345         Key *k;
 346         int blen;
 347         u_int len;
 348         char line[1024];
 349         u_char blob[8096];
 350         char encoded[8096];
 351         struct stat st;
 352         int escaped = 0, private = 0, ok;
 353         FILE *fp;
 354
 355         if (!have_identity)
 356                 ask_filename(pw, "Enter file in which the key is");
 357         if (stat(identity_file, &st) < 0) {
 358                 perror(identity_file);
 359                 exit(1);
 360         }
 361         fp = fopen(identity_file, "r");
 362         if (fp == NULL) {
 363                 perror(identity_file);
 364                 exit(1);
 365         }
 366         encoded[0] = '\0';
 367         while ((blen = get_line(fp, line, sizeof(line))) != -1) {
 368                 if (line[blen - 1] == '\\')
 369                         escaped++;
 370                 if (strncmp(line, "----", 4) == 0 ||
 371                     strstr(line, ": ") != NULL) {
 372                         if (strstr(line, SSH_COM_PRIVATE_BEGIN) != NULL)
 373                                 private = 1;
 374                         if (strstr(line, " END ") != NULL) {
 375                                 break;
 376                         }
 377                         /* fprintf(stderr, "ignore: %s", line); */
 378                         continue;
 379                 }
 380                 if (escaped) {
 381                         escaped--;
 382                         /* fprintf(stderr, "escaped: %s", line); */
 383                         continue;
 384                 }
 385                 strlcat(encoded, line, sizeof(encoded));
 386         }
 387         len = strlen(encoded);
 388         if (((len % 4) == 3) &&
 389             (encoded[len-1] == '=') &&
 390             (encoded[len-2] == '=') &&
 391             (encoded[len-3] == '='))
 392                 encoded[len-3] = '\0';
 393         blen = uudecode(encoded, blob, sizeof(blob));
 394         if (blen < 0) {
 395                 fprintf(stderr, "uudecode failed.\n");
 396                 exit(1);
 397         }
 398         k = private ?
 399             do_convert_private_ssh2_from_blob(blob, blen) :
 400             key_from_blob(blob, blen);
 401         if (k == NULL) {
 402                 fprintf(stderr, "decode blob failed.\n");
 403                 exit(1);
 404         }
 405         ok = private ?
 406             (k->type == KEY_DSA ?
 407                  PEM_write_DSAPrivateKey(stdout, k->dsa, NULL, NULL, 0, NULL, NULL) :
 408                  PEM_write_RSAPrivateKey(stdout, k->rsa, NULL, NULL, 0, NULL, NULL)) :
 409             key_write(k, stdout);
 410         if (!ok) {
 411                 fprintf(stderr, "key write failed");
 412                 exit(1);
 413         }
 414         key_free(k);
 415         if (!private)
 416                 fprintf(stdout, "\n");
 417         fclose(fp);
 418         exit(0);
 419 }
 420
 421 static void
 422 do_print_public(struct passwd *pw)
 423 {
 424         Key *prv;
 425         struct stat st;
 426
 427         if (!have_identity)
 428                 ask_filename(pw, "Enter file in which the key is");
 429         if (stat(identity_file, &st) < 0) {
 430                 perror(identity_file);
 431                 exit(1);
 432         }
 433         prv = load_identity(identity_file);
 434         if (prv == NULL) {
 435                 fprintf(stderr, "load failed\n");
 436                 exit(1);
 437         }
 438         if (!key_write(prv, stdout))
 439                 fprintf(stderr, "key_write failed");
 440         key_free(prv);
 441         fprintf(stdout, "\n");
 442         exit(0);
 443 }
 444
 445 #ifdef SMARTCARD
 446 static void
 447 do_upload(struct passwd *pw, const char *sc_reader_id)
 448 {
 449         Key *prv = NULL;
 450         struct stat st;
 451         int ret;
 452
 453         if (!have_identity)
 454                 ask_filename(pw, "Enter file in which the key is");
 455         if (stat(identity_file, &st) < 0) {
 456                 perror(identity_file);
 457                 exit(1);
 458         }
 459         prv = load_identity(identity_file);
 460         if (prv == NULL) {
 461                 error("load failed");
 462                 exit(1);
 463         }
 464         ret = sc_put_key(prv, sc_reader_id);
 465         key_free(prv);
 466         if (ret < 0)
 467                 exit(1);
 468         logit("loading key done");
 469         exit(0);
 470 }
 471
 472 static void
 473 do_download(struct passwd *pw, const char *sc_reader_id)
 474 {
 475         Key **keys = NULL;
 476         int i;
 477
 478         keys = sc_get_keys(sc_reader_id, NULL);
 479         if (keys == NULL)
 480                 fatal("cannot read public key from smartcard");
 481         for (i = 0; keys[i]; i++) {
 482                 key_write(keys[i], stdout);
 483                 key_free(keys[i]);
 484                 fprintf(stdout, "\n");
 485         }
 486         xfree(keys);
 487         exit(0);
 488 }
 489 #endif /* SMARTCARD */
 490
 491 static void
 492 do_fingerprint(struct passwd *pw)
 493 {
 494         FILE *f;
 495         Key *public;
 496         char *comment = NULL, *cp, *ep, line[16*1024], *fp;
 497         int i, skip = 0, num = 1, invalid = 1;
 498         enum fp_rep rep;
 499         enum fp_type fptype;
 500         struct stat st;
 501
 502         fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
 503         rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
 504
 505         if (!have_identity)
 506                 ask_filename(pw, "Enter file in which the key is");
 507         if (stat(identity_file, &st) < 0) {
 508                 perror(identity_file);
 509                 exit(1);
 510         }
 511         public = key_load_public(identity_file, &comment);
 512         if (public != NULL) {
 513                 fp = key_fingerprint(public, fptype, rep);
 514                 printf("%u %s %s\n", key_size(public), fp, comment);
 515                 key_free(public);
 516                 xfree(comment);
 517                 xfree(fp);
 518                 exit(0);
 519         }
 520         if (comment) {
 521                 xfree(comment);
 522                 comment = NULL;
 523         }
 524
 525         f = fopen(identity_file, "r");
 526         if (f != NULL) {
 527                 while (fgets(line, sizeof(line), f)) {
 528                         i = strlen(line) - 1;
 529                         if (line[i] != '\n') {
 530                                 error("line %d too long: %.40s...", num, line);
 531                                 skip = 1;
 532                                 continue;
 533                         }
 534                         num++;
 535                         if (skip) {
 536                                 skip = 0;
 537                                 continue;
 538                         }
 539                         line[i] = '\0';
 540
 541                         /* Skip leading whitespace, empty and comment lines. */
 542                         for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 543                                 ;
 544                         if (!*cp || *cp == '\n' || *cp == '#')
 545                                 continue ;
 546                         i = strtol(cp, &ep, 10);
 547                         if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
 548                                 int quoted = 0;
 549                                 comment = cp;
 550                                 for (; *cp && (quoted || (*cp != ' ' &&
 551                                     *cp != '\t')); cp++) {
 552                                         if (*cp == '\\' && cp[1] == '"')
 553                                                 cp++;   /* Skip both */
 554                                         else if (*cp == '"')
 555                                                 quoted = !quoted;
 556                                 }
 557                                 if (!*cp)
 558                                         continue;
 559                                 *cp++ = '\0';
 560                         }
 561                         ep = cp;
 562                         public = key_new(KEY_RSA1);
 563                         if (key_read(public, &cp) != 1) {
 564                                 cp = ep;
 565                                 key_free(public);
 566                                 public = key_new(KEY_UNSPEC);
 567                                 if (key_read(public, &cp) != 1) {
 568                                         key_free(public);
 569                                         continue;
 570                                 }
 571                         }
 572                         comment = *cp ? cp : comment;
 573                         fp = key_fingerprint(public, fptype, rep);
 574                         printf("%u %s %s\n", key_size(public), fp,
 575                             comment ? comment : "no comment");
 576                         xfree(fp);
 577                         key_free(public);
 578                         invalid = 0;
 579                 }
 580                 fclose(f);
 581         }
 582         if (invalid) {
 583                 printf("%s is not a public key file.\n", identity_file);
 584                 exit(1);
 585         }
 586         exit(0);
 587 }
 588
 589 static void
 590 print_host(FILE *f, char *name, Key *public, int hash)
 591 {
 592         if (hash && (name = host_hash(name, NULL, 0)) == NULL)
 593                 fatal("hash_host failed");
 594         fprintf(f, "%s ", name);
 595         if (!key_write(public, f))
 596                 fatal("key_write failed");
 597         fprintf(f, "\n");
 598 }
 599
 600 static void
 601 do_known_hosts(struct passwd *pw, const char *name)
 602 {
 603         FILE *in, *out = stdout;
 604         Key *public;
 605         char *cp, *cp2, *kp, *kp2;
 606         char line[16*1024], tmp[MAXPATHLEN], old[MAXPATHLEN];
 607         int c, i, skip = 0, inplace = 0, num = 0, invalid = 0, has_unhashed = 0;
 608
 609         if (!have_identity) {
 610                 cp = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
 611                 if (strlcpy(identity_file, cp, sizeof(identity_file)) >=
 612                     sizeof(identity_file))
 613                         fatal("Specified known hosts path too long");
 614                 xfree(cp);
 615                 have_identity = 1;
 616         }
 617         if ((in = fopen(identity_file, "r")) == NULL)
 618                 fatal("fopen: %s", strerror(errno));
 619
 620         /*
 621          * Find hosts goes to stdout, hash and deletions happen in-place
 622          * A corner case is ssh-keygen -HF foo, which should go to stdout
 623          */
 624         if (!find_host && (hash_hosts || delete_host)) {
 625                 if (strlcpy(tmp, identity_file, sizeof(tmp)) >= sizeof(tmp) ||
 626                     strlcat(tmp, ".XXXXXXXXXX", sizeof(tmp)) >= sizeof(tmp) ||
 627                     strlcpy(old, identity_file, sizeof(old)) >= sizeof(old) ||
 628                     strlcat(old, ".old", sizeof(old)) >= sizeof(old))
 629                         fatal("known_hosts path too long");
 630                 umask(077);
 631                 if ((c = mkstemp(tmp)) == -1)
 632                         fatal("mkstemp: %s", strerror(errno));
 633                 if ((out = fdopen(c, "w")) == NULL) {
 634                         c = errno;
 635                         unlink(tmp);
 636                         fatal("fdopen: %s", strerror(c));
 637                 }
 638                 inplace = 1;
 639         }
 640
 641         while (fgets(line, sizeof(line), in)) {
 642                 num++;
 643                 i = strlen(line) - 1;
 644                 if (line[i] != '\n') {
 645                         error("line %d too long: %.40s...", num, line);
 646                         skip = 1;
 647                         invalid = 1;
 648                         continue;
 649                 }
 650                 if (skip) {
 651                         skip = 0;
 652                         continue;
 653                 }
 654                 line[i] = '\0';
 655
 656                 /* Skip leading whitespace, empty and comment lines. */
 657                 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 658                         ;
 659                 if (!*cp || *cp == '\n' || *cp == '#') {
 660                         if (inplace)
 661                                 fprintf(out, "%s\n", cp);
 662                         continue;
 663                 }
 664                 /* Find the end of the host name portion. */
 665                 for (kp = cp; *kp && *kp != ' ' && *kp != '\t'; kp++)
 666                         ;
 667                 if (*kp == '\0' || *(kp + 1) == '\0') {
 668                         error("line %d missing key: %.40s...",
 669                             num, line);
 670                         invalid = 1;
 671                         continue;
 672                 }
 673                 *kp++ = '\0';
 674                 kp2 = kp;
 675
 676                 public = key_new(KEY_RSA1);
 677                 if (key_read(public, &kp) != 1) {
 678                         kp = kp2;
 679                         key_free(public);
 680                         public = key_new(KEY_UNSPEC);
 681                         if (key_read(public, &kp) != 1) {
 682                                 error("line %d invalid key: %.40s...",
 683                                     num, line);
 684                                 key_free(public);
 685                                 invalid = 1;
 686                                 continue;
 687                         }
 688                 }
 689
 690                 if (*cp == HASH_DELIM) {
 691                         if (find_host || delete_host) {
 692                                 cp2 = host_hash(name, cp, strlen(cp));
 693                                 if (cp2 == NULL) {
 694                                         error("line %d: invalid hashed "
 695                                             "name: %.64s...", num, line);
 696                                         invalid = 1;
 697                                         continue;
 698                                 }
 699                                 c = (strcmp(cp2, cp) == 0);
 700                                 if (find_host && c) {
 701                                         printf("# Host %s found: "
 702                                             "line %d type %s\n", name,
 703                                             num, key_type(public));
 704                                         print_host(out, cp, public, 0);
 705                                 }
 706                                 if (delete_host && !c)
 707                                         print_host(out, cp, public, 0);
 708                         } else if (hash_hosts)
 709                                 print_host(out, cp, public, 0);
 710                 } else {
 711                         if (find_host || delete_host) {
 712                                 c = (match_hostname(name, cp,
 713                                     strlen(cp)) == 1);
 714                                 if (find_host && c) {
 715                                         printf("# Host %s found: "
 716                                             "line %d type %s\n", name,
 717                                             num, key_type(public));
 718                                         print_host(out, cp, public, hash_hosts);
 719                                 }
 720                                 if (delete_host && !c)
 721                                         print_host(out, cp, public, 0);
 722                         } else if (hash_hosts) {
 723                                 for (cp2 = strsep(&cp, ",");
 724                                     cp2 != NULL && *cp2 != '\0';
 725                                     cp2 = strsep(&cp, ",")) {
 726                                         if (strcspn(cp2, "*?!") != strlen(cp2))
 727                                                 fprintf(stderr, "Warning: "
 728                                                     "ignoring host name with "
 729                                                     "metacharacters: %.64s\n",
 730                                                     cp2);
 731                                         else
 732                                                 print_host(out, cp2, public, 1);
 733                                 }
 734                                 has_unhashed = 1;
 735                         }
 736                 }
 737                 key_free(public);
 738         }
 739         fclose(in);
 740
 741         if (invalid) {
 742                 fprintf(stderr, "%s is not a valid known_host file.\n",
 743                     identity_file);
 744                 if (inplace) {
 745                         fprintf(stderr, "Not replacing existing known_hosts "
 746                             "file because of errors\n");
 747                         fclose(out);
 748                         unlink(tmp);
 749                 }
 750                 exit(1);
 751         }
 752
 753         if (inplace) {
 754                 fclose(out);
 755
 756                 /* Backup existing file */
 757                 if (unlink(old) == -1 && errno != ENOENT)
 758                         fatal("unlink %.100s: %s", old, strerror(errno));
 759                 if (link(identity_file, old) == -1)
 760                         fatal("link %.100s to %.100s: %s", identity_file, old,
 761                             strerror(errno));
 762                 /* Move new one into place */
 763                 if (rename(tmp, identity_file) == -1) {
 764                         error("rename\"%s\" to \"%s\": %s", tmp, identity_file,
 765                             strerror(errno));
 766                         unlink(tmp);
 767                         unlink(old);
 768                         exit(1);
 769                 }
 770
 771                 fprintf(stderr, "%s updated.\n", identity_file);
 772                 fprintf(stderr, "Original contents retained as %s\n", old);
 773                 if (has_unhashed) {
 774                         fprintf(stderr, "WARNING: %s contains unhashed "
 775                             "entries\n", old);
 776                         fprintf(stderr, "Delete this file to ensure privacy "
 777                             "of hostnames\n");
 778                 }
 779         }
 780
 781         exit(0);
 782 }
 783
 784 /*
 785  * Perform changing a passphrase.  The argument is the passwd structure
 786  * for the current user.
 787  */
 788 static void
 789 do_change_passphrase(struct passwd *pw)
 790 {
 791         char *comment;
 792         char *old_passphrase, *passphrase1, *passphrase2;
 793         struct stat st;
 794         Key *private;
 795
 796         if (!have_identity)
 797                 ask_filename(pw, "Enter file in which the key is");
 798         if (stat(identity_file, &st) < 0) {
 799                 perror(identity_file);
 800                 exit(1);
 801         }
 802         /* Try to load the file with empty passphrase. */
 803         private = key_load_private(identity_file, "", &comment);
 804         if (private == NULL) {
 805                 if (identity_passphrase)
 806                         old_passphrase = xstrdup(identity_passphrase);
 807                 else
 808                         old_passphrase =
 809                             read_passphrase("Enter old passphrase: ",
 810                             RP_ALLOW_STDIN);
 811                 private = key_load_private(identity_file, old_passphrase,
 812                     &comment);
 813                 memset(old_passphrase, 0, strlen(old_passphrase));
 814                 xfree(old_passphrase);
 815                 if (private == NULL) {
 816                         printf("Bad passphrase.\n");
 817                         exit(1);
 818                 }
 819         }
 820         printf("Key has comment '%s'\n", comment);
 821
 822         /* Ask the new passphrase (twice). */
 823         if (identity_new_passphrase) {
 824                 passphrase1 = xstrdup(identity_new_passphrase);
 825                 passphrase2 = NULL;
 826         } else {
 827                 passphrase1 =
 828                         read_passphrase("Enter new passphrase (empty for no "
 829                             "passphrase): ", RP_ALLOW_STDIN);
 830                 passphrase2 = read_passphrase("Enter same passphrase again: ",
 831                     RP_ALLOW_STDIN);
 832
 833                 /* Verify that they are the same. */
 834                 if (strcmp(passphrase1, passphrase2) != 0) {
 835                         memset(passphrase1, 0, strlen(passphrase1));
 836                         memset(passphrase2, 0, strlen(passphrase2));
 837                         xfree(passphrase1);
 838                         xfree(passphrase2);
 839                         printf("Pass phrases do not match.  Try again.\n");
 840                         exit(1);
 841                 }
 842                 /* Destroy the other copy. */
 843                 memset(passphrase2, 0, strlen(passphrase2));
 844                 xfree(passphrase2);
 845         }
 846
 847         /* Save the file using the new passphrase. */
 848         if (!key_save_private(private, identity_file, passphrase1, comment)) {
 849                 printf("Saving the key failed: %s.\n", identity_file);
 850                 memset(passphrase1, 0, strlen(passphrase1));
 851                 xfree(passphrase1);
 852                 key_free(private);
 853                 xfree(comment);
 854                 exit(1);
 855         }
 856         /* Destroy the passphrase and the copy of the key in memory. */
 857         memset(passphrase1, 0, strlen(passphrase1));
 858         xfree(passphrase1);
 859         key_free(private);               /* Destroys contents */
 860         xfree(comment);
 861
 862         printf("Your identification has been saved with the new passphrase.\n");
 863         exit(0);
 864 }
 865
 866 /*
 867  * Print the SSHFP RR.
 868  */
 869 static int
 870 do_print_resource_record(struct passwd *pw, char *fname, char *hname)
 871 {
 872         Key *public;
 873         char *comment = NULL;
 874         struct stat st;
 875
 876         if (fname == NULL)
 877                 ask_filename(pw, "Enter file in which the key is");
 878         if (stat(fname, &st) < 0) {
 879                 if (errno == ENOENT)
 880                         return 0;
 881                 perror(fname);
 882                 exit(1);
 883         }
 884         public = key_load_public(fname, &comment);
 885         if (public != NULL) {
 886                 export_dns_rr(hname, public, stdout, print_generic);
 887                 key_free(public);
 888                 xfree(comment);
 889                 return 1;
 890         }
 891         if (comment)
 892                 xfree(comment);
 893
 894         printf("failed to read v2 public key from %s.\n", fname);
 895         exit(1);
 896 }
 897
 898 /*
 899  * Change the comment of a private key file.
 900  */
 901 static void
 902 do_change_comment(struct passwd *pw)
 903 {
 904         char new_comment[1024], *comment, *passphrase;
 905         Key *private;
 906         Key *public;
 907         struct stat st;
 908         FILE *f;
 909         int fd;
 910
 911         if (!have_identity)
 912                 ask_filename(pw, "Enter file in which the key is");
 913         if (stat(identity_file, &st) < 0) {
 914                 perror(identity_file);
 915                 exit(1);
 916         }
 917         private = key_load_private(identity_file, "", &comment);
 918         if (private == NULL) {
 919                 if (identity_passphrase)
 920                         passphrase = xstrdup(identity_passphrase);
 921                 else if (identity_new_passphrase)
 922                         passphrase = xstrdup(identity_new_passphrase);
 923                 else
 924                         passphrase = read_passphrase("Enter passphrase: ",
 925                             RP_ALLOW_STDIN);
 926                 /* Try to load using the passphrase. */
 927                 private = key_load_private(identity_file, passphrase, &comment);
 928                 if (private == NULL) {
 929                         memset(passphrase, 0, strlen(passphrase));
 930                         xfree(passphrase);
 931                         printf("Bad passphrase.\n");
 932                         exit(1);
 933                 }
 934         } else {
 935                 passphrase = xstrdup("");
 936         }
 937         if (private->type != KEY_RSA1) {
 938                 fprintf(stderr, "Comments are only supported for RSA1 keys.\n");
 939                 key_free(private);
 940                 exit(1);
 941         }
 942         printf("Key now has comment '%s'\n", comment);
 943
 944         if (identity_comment) {
 945                 strlcpy(new_comment, identity_comment, sizeof(new_comment));
 946         } else {
 947                 printf("Enter new comment: ");
 948                 fflush(stdout);
 949                 if (!fgets(new_comment, sizeof(new_comment), stdin)) {
 950                         memset(passphrase, 0, strlen(passphrase));
 951                         key_free(private);
 952                         exit(1);
 953                 }
 954                 if (strchr(new_comment, '\n'))
 955                         *strchr(new_comment, '\n') = 0;
 956         }
 957
 958         /* Save the file using the new passphrase. */
 959         if (!key_save_private(private, identity_file, passphrase, new_comment)) {
 960                 printf("Saving the key failed: %s.\n", identity_file);
 961                 memset(passphrase, 0, strlen(passphrase));
 962                 xfree(passphrase);
 963                 key_free(private);
 964                 xfree(comment);
 965                 exit(1);
 966         }
 967         memset(passphrase, 0, strlen(passphrase));
 968         xfree(passphrase);
 969         public = key_from_private(private);
 970         key_free(private);
 971
 972         strlcat(identity_file, ".pub", sizeof(identity_file));
 973         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 974         if (fd == -1) {
 975                 printf("Could not save your public key in %s\n", identity_file);
 976                 exit(1);
 977         }
 978         f = fdopen(fd, "w");
 979         if (f == NULL) {
 980                 printf("fdopen %s failed", identity_file);
 981                 exit(1);
 982         }
 983         if (!key_write(public, f))
 984                 fprintf(stderr, "write key failed");
 985         key_free(public);
 986         fprintf(f, " %s\n", new_comment);
 987         fclose(f);
 988
 989         xfree(comment);
 990
 991         printf("The comment in your key file has been changed.\n");
 992         exit(0);
 993 }
 994
 995 static void
 996 usage(void)
 997 {
 998         fprintf(stderr, "Usage: %s [options]\n", __progname);
 999         fprintf(stderr, "Options:\n");
1000         fprintf(stderr, "  -a trials   Number of trials for screening DH-GEX moduli.\n");
1001         fprintf(stderr, "  -B          Show bubblebabble digest of key file.\n");
1002         fprintf(stderr, "  -b bits     Number of bits in the key to create.\n");
1003         fprintf(stderr, "  -C comment  Provide new comment.\n");
1004         fprintf(stderr, "  -c          Change comment in private and public key files.\n");
1005 #ifdef SMARTCARD
1006         fprintf(stderr, "  -D reader   Download public key from smartcard.\n");
1007 #endif /* SMARTCARD */
1008         fprintf(stderr, "  -e          Convert OpenSSH to IETF SECSH key file.\n");
1009         fprintf(stderr, "  -F hostname Find hostname in known hosts file.\n");
1010         fprintf(stderr, "  -f filename Filename of the key file.\n");
1011         fprintf(stderr, "  -G file     Generate candidates for DH-GEX moduli.\n");
1012         fprintf(stderr, "  -g          Use generic DNS resource record format.\n");
1013         fprintf(stderr, "  -H          Hash names in known_hosts file.\n");
1014         fprintf(stderr, "  -i          Convert IETF SECSH to OpenSSH key file.\n");
1015         fprintf(stderr, "  -l          Show fingerprint of key file.\n");
1016         fprintf(stderr, "  -M memory   Amount of memory (MB) to use for generating DH-GEX moduli.\n");
1017         fprintf(stderr, "  -N phrase   Provide new passphrase.\n");
1018         fprintf(stderr, "  -P phrase   Provide old passphrase.\n");
1019         fprintf(stderr, "  -p          Change passphrase of private key file.\n");
1020         fprintf(stderr, "  -q          Quiet.\n");
1021         fprintf(stderr, "  -R hostname Remove host from known_hosts file.\n");
1022         fprintf(stderr, "  -r hostname Print DNS resource record.\n");
1023         fprintf(stderr, "  -S start    Start point (hex) for generating DH-GEX moduli.\n");
1024         fprintf(stderr, "  -T file     Screen candidates for DH-GEX moduli.\n");
1025         fprintf(stderr, "  -t type     Specify type of key to create.\n");
1026 #ifdef SMARTCARD
1027         fprintf(stderr, "  -U reader   Upload private key to smartcard.\n");
1028 #endif /* SMARTCARD */
1029         fprintf(stderr, "  -v          Verbose.\n");
1030         fprintf(stderr, "  -W gen      Generator to use for generating DH-GEX moduli.\n");
1031         fprintf(stderr, "  -y          Read private key file and print public key.\n");
1032
1033         exit(1);
1034 }
1035
1036 /*
1037  * Main program for key management.
1038  */
1039 int
1040 main(int ac, char **av)
1041 {
1042         char dotsshdir[MAXPATHLEN], comment[1024], *passphrase1, *passphrase2;
1043         char out_file[MAXPATHLEN], *reader_id = NULL;
1044         char *rr_hostname = NULL;
1045         Key *private, *public;
1046         struct passwd *pw;
1047         struct stat st;
1048         int opt, type, fd, download = 0;
1049         u_int32_t memory = 0, generator_wanted = 0, trials = 100;
1050         int do_gen_candidates = 0, do_screen_candidates = 0;
1051         int log_level = SYSLOG_LEVEL_INFO;
1052         BIGNUM *start = NULL;
1053         FILE *f;
1054         const char *errstr;
1055
1056         extern int optind;
1057         extern char *optarg;
1058
1059         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1060         sanitise_stdfd();
1061
1062         __progname = ssh_get_progname(av[0]);
1063
1064         SSLeay_add_all_algorithms();
1065         log_init(av[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
1066
1067         init_rng();
1068         seed_rng();
1069
1070         /* we need this for the home * directory.  */
1071         pw = getpwuid(getuid());
1072         if (!pw) {
1073                 printf("You don't exist, go away!\n");
1074                 exit(1);
1075         }
1076         if (gethostname(hostname, sizeof(hostname)) < 0) {
1077                 perror("gethostname");
1078                 exit(1);
1079         }
1080
1081         while ((opt = getopt(ac, av,
1082             "degiqpclBHvxXyF:b:f:t:U:D:P:N:C:r:g:R:T:G:M:S:a:W:")) != -1) {
1083                 switch (opt) {
1084                 case 'b':
1085                         bits = (u_int32_t)strtonum(optarg, 768, 32768, &errstr);
1086                         if (errstr)
1087                                 fatal("Bits has bad value %s (%s)",
1088                                         optarg, errstr);
1089                         break;
1090                 case 'F':
1091                         find_host = 1;
1092                         rr_hostname = optarg;
1093                         break;
1094                 case 'H':
1095                         hash_hosts = 1;
1096                         break;
1097                 case 'R':
1098                         delete_host = 1;
1099                         rr_hostname = optarg;
1100                         break;
1101                 case 'l':
1102                         print_fingerprint = 1;
1103                         break;
1104                 case 'B':
1105                         print_bubblebabble = 1;
1106                         break;
1107                 case 'p':
1108                         change_passphrase = 1;
1109                         break;
1110                 case 'c':
1111                         change_comment = 1;
1112                         break;
1113                 case 'f':
1114                         if (strlcpy(identity_file, optarg, sizeof(identity_file)) >=
1115                             sizeof(identity_file))
1116                                 fatal("Identity filename too long");
1117                         have_identity = 1;
1118                         break;
1119                 case 'g':
1120                         print_generic = 1;
1121                         break;
1122                 case 'P':
1123                         identity_passphrase = optarg;
1124                         break;
1125                 case 'N':
1126                         identity_new_passphrase = optarg;
1127                         break;
1128                 case 'C':
1129                         identity_comment = optarg;
1130                         break;
1131                 case 'q':
1132                         quiet = 1;
1133                         break;
1134                 case 'e':
1135                 case 'x':
1136                         /* export key */
1137                         convert_to_ssh2 = 1;
1138                         break;
1139                 case 'i':
1140                 case 'X':
1141                         /* import key */
1142                         convert_from_ssh2 = 1;
1143                         break;
1144                 case 'y':
1145                         print_public = 1;
1146                         break;
1147                 case 'd':
1148                         key_type_name = "dsa";
1149                         break;
1150                 case 't':
1151                         key_type_name = optarg;
1152                         break;
1153                 case 'D':
1154                         download = 1;
1155                         /*FALLTHROUGH*/
1156                 case 'U':
1157                         reader_id = optarg;
1158                         break;
1159                 case 'v':
1160                         if (log_level == SYSLOG_LEVEL_INFO)
1161                                 log_level = SYSLOG_LEVEL_DEBUG1;
1162                         else {
1163                                 if (log_level >= SYSLOG_LEVEL_DEBUG1 &&
1164                                     log_level < SYSLOG_LEVEL_DEBUG3)
1165                                         log_level++;
1166                         }
1167                         break;
1168                 case 'r':
1169                         rr_hostname = optarg;
1170                         break;
1171                 case 'W':
1172                         generator_wanted = (u_int32_t)strtonum(optarg, 1,
1173                             UINT_MAX, &errstr);
1174                         if (errstr)
1175                                 fatal("Desired generator has bad value: %s (%s)",
1176                                         optarg, errstr);
1177                         break;
1178                 case 'a':
1179                         trials = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1180                         if (errstr)
1181                                 fatal("Invalid number of trials: %s (%s)",
1182                                         optarg, errstr);
1183                         break;
1184                 case 'M':
1185                         memory = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1186                         if (errstr) {
1187                                 fatal("Memory limit is %s: %s", errstr, optarg);
1188                         }
1189                         break;
1190                 case 'G':
1191                         do_gen_candidates = 1;
1192                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1193                             sizeof(out_file))
1194                                 fatal("Output filename too long");
1195                         break;
1196                 case 'T':
1197                         do_screen_candidates = 1;
1198                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1199                             sizeof(out_file))
1200                                 fatal("Output filename too long");
1201                         break;
1202                 case 'S':
1203                         /* XXX - also compare length against bits */
1204                         if (BN_hex2bn(&start, optarg) == 0)
1205                                 fatal("Invalid start point.");
1206                         break;
1207                 case '?':
1208                 default:
1209                         usage();
1210                 }
1211         }
1212
1213         /* reinit */
1214         log_init(av[0], log_level, SYSLOG_FACILITY_USER, 1);
1215
1216         if (optind < ac) {
1217                 printf("Too many arguments.\n");
1218                 usage();
1219         }
1220         if (change_passphrase && change_comment) {
1221                 printf("Can only have one of -p and -c.\n");
1222                 usage();
1223         }
1224         if (delete_host || hash_hosts || find_host)
1225                 do_known_hosts(pw, rr_hostname);
1226         if (print_fingerprint || print_bubblebabble)
1227                 do_fingerprint(pw);
1228         if (change_passphrase)
1229                 do_change_passphrase(pw);
1230         if (change_comment)
1231                 do_change_comment(pw);
1232         if (convert_to_ssh2)
1233                 do_convert_to_ssh2(pw);
1234         if (convert_from_ssh2)
1235                 do_convert_from_ssh2(pw);
1236         if (print_public)
1237                 do_print_public(pw);
1238         if (rr_hostname != NULL) {
1239                 unsigned int n = 0;
1240
1241                 if (have_identity) {
1242                         n = do_print_resource_record(pw,
1243                             identity_file, rr_hostname);
1244                         if (n == 0) {
1245                                 perror(identity_file);
1246                                 exit(1);
1247                         }
1248                         exit(0);
1249                 } else {
1250
1251                         n += do_print_resource_record(pw,
1252                             _PATH_HOST_RSA_KEY_FILE, rr_hostname);
1253                         n += do_print_resource_record(pw,
1254                             _PATH_HOST_DSA_KEY_FILE, rr_hostname);
1255
1256                         if (n == 0)
1257                                 fatal("no keys found.");
1258                         exit(0);
1259                 }
1260         }
1261         if (reader_id != NULL) {
1262 #ifdef SMARTCARD
1263                 if (download)
1264                         do_download(pw, reader_id);
1265                 else
1266                         do_upload(pw, reader_id);
1267 #else /* SMARTCARD */
1268                 fatal("no support for smartcards.");
1269 #endif /* SMARTCARD */
1270         }
1271
1272         if (do_gen_candidates) {
1273                 FILE *out = fopen(out_file, "w");
1274
1275                 if (out == NULL) {
1276                         error("Couldn't open modulus candidate file \"%s\": %s",
1277                             out_file, strerror(errno));
1278                         return (1);
1279                 }
1280                 if (bits == 0)
1281                         bits = DEFAULT_BITS;
1282                 if (gen_candidates(out, memory, bits, start) != 0)
1283                         fatal("modulus candidate generation failed");
1284
1285                 return (0);
1286         }
1287
1288         if (do_screen_candidates) {
1289                 FILE *in;
1290                 FILE *out = fopen(out_file, "w");
1291
1292                 if (have_identity && strcmp(identity_file, "-") != 0) {
1293                         if ((in = fopen(identity_file, "r")) == NULL) {
1294                                 fatal("Couldn't open modulus candidate "
1295                                     "file \"%s\": %s", identity_file,
1296                                     strerror(errno));
1297                         }
1298                 } else
1299                         in = stdin;
1300
1301                 if (out == NULL) {
1302                         fatal("Couldn't open moduli file \"%s\": %s",
1303                             out_file, strerror(errno));
1304                 }
1305                 if (prime_test(in, out, trials, generator_wanted) != 0)
1306                         fatal("modulus screening failed");
1307                 return (0);
1308         }
1309
1310         arc4random_stir();
1311
1312         if (key_type_name == NULL)
1313                 key_type_name = "rsa";
1314
1315         type = key_type_from_name(key_type_name);
1316         if (type == KEY_UNSPEC) {
1317                 fprintf(stderr, "unknown key type %s\n", key_type_name);
1318                 exit(1);
1319         }
1320         if (bits == 0)
1321                 bits = (type == KEY_DSA) ? DEFAULT_BITS_DSA : DEFAULT_BITS;
1322         if (type == KEY_DSA && bits != 1024)
1323                 fatal("DSA keys must be 1024 bits");
1324         if (!quiet)
1325                 printf("Generating public/private %s key pair.\n", key_type_name);
1326         private = key_generate(type, bits);
1327         if (private == NULL) {
1328                 fprintf(stderr, "key_generate failed");
1329                 exit(1);
1330         }
1331         public  = key_from_private(private);
1332
1333         if (!have_identity)
1334                 ask_filename(pw, "Enter file in which to save the key");
1335
1336         /* Create ~/.ssh directory if it doesn't already exist. */
1337         snprintf(dotsshdir, sizeof dotsshdir, "%s/%s", pw->pw_dir, _PATH_SSH_USER_DIR);
1338         if (strstr(identity_file, dotsshdir) != NULL &&
1339             stat(dotsshdir, &st) < 0) {
1340                 if (mkdir(dotsshdir, 0700) < 0)
1341                         error("Could not create directory '%s'.", dotsshdir);
1342                 else if (!quiet)
1343                         printf("Created directory '%s'.\n", dotsshdir);
1344         }
1345         /* If the file already exists, ask the user to confirm. */
1346         if (stat(identity_file, &st) >= 0) {
1347                 char yesno[3];
1348                 printf("%s already exists.\n", identity_file);
1349                 printf("Overwrite (y/n)? ");
1350                 fflush(stdout);
1351                 if (fgets(yesno, sizeof(yesno), stdin) == NULL)
1352                         exit(1);
1353                 if (yesno[0] != 'y' && yesno[0] != 'Y')
1354                         exit(1);
1355         }
1356         /* Ask for a passphrase (twice). */
1357         if (identity_passphrase)
1358                 passphrase1 = xstrdup(identity_passphrase);
1359         else if (identity_new_passphrase)
1360                 passphrase1 = xstrdup(identity_new_passphrase);
1361         else {
1362 passphrase_again:
1363                 passphrase1 =
1364                         read_passphrase("Enter passphrase (empty for no "
1365                             "passphrase): ", RP_ALLOW_STDIN);
1366                 passphrase2 = read_passphrase("Enter same passphrase again: ",
1367                     RP_ALLOW_STDIN);
1368                 if (strcmp(passphrase1, passphrase2) != 0) {
1369                         /*
1370                          * The passphrases do not match.  Clear them and
1371                          * retry.
1372                          */
1373                         memset(passphrase1, 0, strlen(passphrase1));
1374                         memset(passphrase2, 0, strlen(passphrase2));
1375                         xfree(passphrase1);
1376                         xfree(passphrase2);
1377                         printf("Passphrases do not match.  Try again.\n");
1378                         goto passphrase_again;
1379                 }
1380                 /* Clear the other copy of the passphrase. */
1381                 memset(passphrase2, 0, strlen(passphrase2));
1382                 xfree(passphrase2);
1383         }
1384
1385         if (identity_comment) {
1386                 strlcpy(comment, identity_comment, sizeof(comment));
1387         } else {
1388                 /* Create default commend field for the passphrase. */
1389                 snprintf(comment, sizeof comment, "%s@%s", pw->pw_name, hostname);
1390         }
1391
1392         /* Save the key with the given passphrase and comment. */
1393         if (!key_save_private(private, identity_file, passphrase1, comment)) {
1394                 printf("Saving the key failed: %s.\n", identity_file);
1395                 memset(passphrase1, 0, strlen(passphrase1));
1396                 xfree(passphrase1);
1397                 exit(1);
1398         }
1399         /* Clear the passphrase. */
1400         memset(passphrase1, 0, strlen(passphrase1));
1401         xfree(passphrase1);
1402
1403         /* Clear the private key and the random number generator. */
1404         key_free(private);
1405         arc4random_stir();
1406
1407         if (!quiet)
1408                 printf("Your identification has been saved in %s.\n", identity_file);
1409
1410         strlcat(identity_file, ".pub", sizeof(identity_file));
1411         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
1412         if (fd == -1) {
1413                 printf("Could not save your public key in %s\n", identity_file);
1414                 exit(1);
1415         }
1416         f = fdopen(fd, "w");
1417         if (f == NULL) {
1418                 printf("fdopen %s failed", identity_file);
1419                 exit(1);
1420         }
1421         if (!key_write(public, f))
1422                 fprintf(stderr, "write key failed");
1423         fprintf(f, " %s\n", comment);
1424         fclose(f);
1425
1426         if (!quiet) {
1427                 char *fp = key_fingerprint(public, SSH_FP_MD5, SSH_FP_HEX);
1428                 printf("Your public key has been saved in %s.\n",
1429                     identity_file);
1430                 printf("The key fingerprint is:\n");
1431                 printf("%s %s\n", fp, comment);
1432                 xfree(fp);
1433         }
1434
1435         key_free(public);
1436         exit(0);
1437 }