ssh-keygen.c

   1 /* $OpenBSD: ssh-keygen.c,v 1.147 2006/07/09 15:15:11 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/socket.h>
  19 #include <sys/stat.h>
  20
  21 #include <openssl/evp.h>
  22 #include <openssl/pem.h>
  23
  24 #include <fcntl.h>
  25 #ifdef HAVE_PATHS_H
  26 # include <paths.h>
  27 #endif
  28 #include <pwd.h>
  29
  30 #include "xmalloc.h"
  31 #include "key.h"
  32 #include "rsa.h"
  33 #include "authfile.h"
  34 #include "uuencode.h"
  35 #include "buffer.h"
  36 #include "bufaux.h"
  37 #include "pathnames.h"
  38 #include "log.h"
  39 #include "misc.h"
  40 #include "match.h"
  41 #include "hostfile.h"
  42 #include "dns.h"
  43
  44 #ifdef SMARTCARD
  45 #include "scard.h"
  46 #endif
  47
  48 /* Number of bits in the RSA/DSA key.  This value can be set on the command line. */
  49 #define DEFAULT_BITS            2048
  50 #define DEFAULT_BITS_DSA        1024
  51 u_int32_t bits = 0;
  52
  53 /*
  54  * Flag indicating that we just want to change the passphrase.  This can be
  55  * set on the command line.
  56  */
  57 int change_passphrase = 0;
  58
  59 /*
  60  * Flag indicating that we just want to change the comment.  This can be set
  61  * on the command line.
  62  */
  63 int change_comment = 0;
  64
  65 int quiet = 0;
  66
  67 /* Flag indicating that we want to hash a known_hosts file */
  68 int hash_hosts = 0;
  69 /* Flag indicating that we want lookup a host in known_hosts file */
  70 int find_host = 0;
  71 /* Flag indicating that we want to delete a host from a known_hosts file */
  72 int delete_host = 0;
  73
  74 /* Flag indicating that we just want to see the key fingerprint */
  75 int print_fingerprint = 0;
  76 int print_bubblebabble = 0;
  77
  78 /* The identity file name, given on the command line or entered by the user. */
  79 char identity_file[1024];
  80 int have_identity = 0;
  81
  82 /* This is set to the passphrase if given on the command line. */
  83 char *identity_passphrase = NULL;
  84
  85 /* This is set to the new passphrase if given on the command line. */
  86 char *identity_new_passphrase = NULL;
  87
  88 /* This is set to the new comment if given on the command line. */
  89 char *identity_comment = NULL;
  90
  91 /* Dump public key file in format used by real and the original SSH 2 */
  92 int convert_to_ssh2 = 0;
  93 int convert_from_ssh2 = 0;
  94 int print_public = 0;
  95 int print_generic = 0;
  96
  97 char *key_type_name = NULL;
  98
  99 /* argv0 */
 100 extern char *__progname;
 101
 102 char hostname[MAXHOSTNAMELEN];
 103
 104 /* moduli.c */
 105 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
 106 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t);
 107
 108 static void
 109 ask_filename(struct passwd *pw, const char *prompt)
 110 {
 111         char buf[1024];
 112         char *name = NULL;
 113
 114         if (key_type_name == NULL)
 115                 name = _PATH_SSH_CLIENT_ID_RSA;
 116         else {
 117                 switch (key_type_from_name(key_type_name)) {
 118                 case KEY_RSA1:
 119                         name = _PATH_SSH_CLIENT_IDENTITY;
 120                         break;
 121                 case KEY_DSA:
 122                         name = _PATH_SSH_CLIENT_ID_DSA;
 123                         break;
 124                 case KEY_RSA:
 125                         name = _PATH_SSH_CLIENT_ID_RSA;
 126                         break;
 127                 default:
 128                         fprintf(stderr, "bad key type");
 129                         exit(1);
 130                         break;
 131                 }
 132         }
 133         snprintf(identity_file, sizeof(identity_file), "%s/%s", pw->pw_dir, name);
 134         fprintf(stderr, "%s (%s): ", prompt, identity_file);
 135         if (fgets(buf, sizeof(buf), stdin) == NULL)
 136                 exit(1);
 137         if (strchr(buf, '\n'))
 138                 *strchr(buf, '\n') = 0;
 139         if (strcmp(buf, "") != 0)
 140                 strlcpy(identity_file, buf, sizeof(identity_file));
 141         have_identity = 1;
 142 }
 143
 144 static Key *
 145 load_identity(char *filename)
 146 {
 147         char *pass;
 148         Key *prv;
 149
 150         prv = key_load_private(filename, "", NULL);
 151         if (prv == NULL) {
 152                 if (identity_passphrase)
 153                         pass = xstrdup(identity_passphrase);
 154                 else
 155                         pass = read_passphrase("Enter passphrase: ",
 156                             RP_ALLOW_STDIN);
 157                 prv = key_load_private(filename, pass, NULL);
 158                 memset(pass, 0, strlen(pass));
 159                 xfree(pass);
 160         }
 161         return prv;
 162 }
 163
 164 #define SSH_COM_PUBLIC_BEGIN            "---- BEGIN SSH2 PUBLIC KEY ----"
 165 #define SSH_COM_PUBLIC_END              "---- END SSH2 PUBLIC KEY ----"
 166 #define SSH_COM_PRIVATE_BEGIN           "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----"
 167 #define SSH_COM_PRIVATE_KEY_MAGIC       0x3f6ff9eb
 168
 169 static void
 170 do_convert_to_ssh2(struct passwd *pw)
 171 {
 172         Key *k;
 173         u_int len;
 174         u_char *blob;
 175         struct stat st;
 176
 177         if (!have_identity)
 178                 ask_filename(pw, "Enter file in which the key is");
 179         if (stat(identity_file, &st) < 0) {
 180                 perror(identity_file);
 181                 exit(1);
 182         }
 183         if ((k = key_load_public(identity_file, NULL)) == NULL) {
 184                 if ((k = load_identity(identity_file)) == NULL) {
 185                         fprintf(stderr, "load failed\n");
 186                         exit(1);
 187                 }
 188         }
 189         if (k->type == KEY_RSA1) {
 190                 fprintf(stderr, "version 1 keys are not supported\n");
 191                 exit(1);
 192         }
 193         if (key_to_blob(k, &blob, &len) <= 0) {
 194                 fprintf(stderr, "key_to_blob failed\n");
 195                 exit(1);
 196         }
 197         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_BEGIN);
 198         fprintf(stdout,
 199             "Comment: \"%u-bit %s, converted from OpenSSH by %s@%s\"\n",
 200             key_size(k), key_type(k),
 201             pw->pw_name, hostname);
 202         dump_base64(stdout, blob, len);
 203         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_END);
 204         key_free(k);
 205         xfree(blob);
 206         exit(0);
 207 }
 208
 209 static void
 210 buffer_get_bignum_bits(Buffer *b, BIGNUM *value)
 211 {
 212         u_int bignum_bits = buffer_get_int(b);
 213         u_int bytes = (bignum_bits + 7) / 8;
 214
 215         if (buffer_len(b) < bytes)
 216                 fatal("buffer_get_bignum_bits: input buffer too small: "
 217                     "need %d have %d", bytes, buffer_len(b));
 218         BN_bin2bn(buffer_ptr(b), bytes, value);
 219         buffer_consume(b, bytes);
 220 }
 221
 222 static Key *
 223 do_convert_private_ssh2_from_blob(u_char *blob, u_int blen)
 224 {
 225         Buffer b;
 226         Key *key = NULL;
 227         char *type, *cipher;
 228         u_char *sig, data[] = "abcde12345";
 229         int magic, rlen, ktype, i1, i2, i3, i4;
 230         u_int slen;
 231         u_long e;
 232
 233         buffer_init(&b);
 234         buffer_append(&b, blob, blen);
 235
 236         magic  = buffer_get_int(&b);
 237         if (magic != SSH_COM_PRIVATE_KEY_MAGIC) {
 238                 error("bad magic 0x%x != 0x%x", magic, SSH_COM_PRIVATE_KEY_MAGIC);
 239                 buffer_free(&b);
 240                 return NULL;
 241         }
 242         i1 = buffer_get_int(&b);
 243         type   = buffer_get_string(&b, NULL);
 244         cipher = buffer_get_string(&b, NULL);
 245         i2 = buffer_get_int(&b);
 246         i3 = buffer_get_int(&b);
 247         i4 = buffer_get_int(&b);
 248         debug("ignore (%d %d %d %d)", i1,i2,i3,i4);
 249         if (strcmp(cipher, "none") != 0) {
 250                 error("unsupported cipher %s", cipher);
 251                 xfree(cipher);
 252                 buffer_free(&b);
 253                 xfree(type);
 254                 return NULL;
 255         }
 256         xfree(cipher);
 257
 258         if (strstr(type, "dsa")) {
 259                 ktype = KEY_DSA;
 260         } else if (strstr(type, "rsa")) {
 261                 ktype = KEY_RSA;
 262         } else {
 263                 buffer_free(&b);
 264                 xfree(type);
 265                 return NULL;
 266         }
 267         key = key_new_private(ktype);
 268         xfree(type);
 269
 270         switch (key->type) {
 271         case KEY_DSA:
 272                 buffer_get_bignum_bits(&b, key->dsa->p);
 273                 buffer_get_bignum_bits(&b, key->dsa->g);
 274                 buffer_get_bignum_bits(&b, key->dsa->q);
 275                 buffer_get_bignum_bits(&b, key->dsa->pub_key);
 276                 buffer_get_bignum_bits(&b, key->dsa->priv_key);
 277                 break;
 278         case KEY_RSA:
 279                 e  = buffer_get_char(&b);
 280                 debug("e %lx", e);
 281                 if (e < 30) {
 282                         e <<= 8;
 283                         e += buffer_get_char(&b);
 284                         debug("e %lx", e);
 285                         e <<= 8;
 286                         e += buffer_get_char(&b);
 287                         debug("e %lx", e);
 288                 }
 289                 if (!BN_set_word(key->rsa->e, e)) {
 290                         buffer_free(&b);
 291                         key_free(key);
 292                         return NULL;
 293                 }
 294                 buffer_get_bignum_bits(&b, key->rsa->d);
 295                 buffer_get_bignum_bits(&b, key->rsa->n);
 296                 buffer_get_bignum_bits(&b, key->rsa->iqmp);
 297                 buffer_get_bignum_bits(&b, key->rsa->q);
 298                 buffer_get_bignum_bits(&b, key->rsa->p);
 299                 rsa_generate_additional_parameters(key->rsa);
 300                 break;
 301         }
 302         rlen = buffer_len(&b);
 303         if (rlen != 0)
 304                 error("do_convert_private_ssh2_from_blob: "
 305                     "remaining bytes in key blob %d", rlen);
 306         buffer_free(&b);
 307
 308         /* try the key */
 309         key_sign(key, &sig, &slen, data, sizeof(data));
 310         key_verify(key, sig, slen, data, sizeof(data));
 311         xfree(sig);
 312         return key;
 313 }
 314
 315 static int
 316 get_line(FILE *fp, char *line, size_t len)
 317 {
 318         int c;
 319         size_t pos = 0;
 320
 321         line[0] = '\0';
 322         while ((c = fgetc(fp)) != EOF) {
 323                 if (pos >= len - 1) {
 324                         fprintf(stderr, "input line too long.\n");
 325                         exit(1);
 326                 }
 327                 switch (c) {
 328                 case '\r':
 329                         c = fgetc(fp);
 330                         if (c != EOF && c != '\n' && ungetc(c, fp) == EOF) {
 331                                 fprintf(stderr, "unget: %s\n", strerror(errno));
 332                                 exit(1);
 333                         }
 334                         return pos;
 335                 case '\n':
 336                         return pos;
 337                 }
 338                 line[pos++] = c;
 339                 line[pos] = '\0';
 340         }
 341         if (c == EOF)
 342                 return -1;
 343         return pos;
 344 }
 345
 346 static void
 347 do_convert_from_ssh2(struct passwd *pw)
 348 {
 349         Key *k;
 350         int blen;
 351         u_int len;
 352         char line[1024];
 353         u_char blob[8096];
 354         char encoded[8096];
 355         struct stat st;
 356         int escaped = 0, private = 0, ok;
 357         FILE *fp;
 358
 359         if (!have_identity)
 360                 ask_filename(pw, "Enter file in which the key is");
 361         if (stat(identity_file, &st) < 0) {
 362                 perror(identity_file);
 363                 exit(1);
 364         }
 365         fp = fopen(identity_file, "r");
 366         if (fp == NULL) {
 367                 perror(identity_file);
 368                 exit(1);
 369         }
 370         encoded[0] = '\0';
 371         while ((blen = get_line(fp, line, sizeof(line))) != -1) {
 372                 if (line[blen - 1] == '\\')
 373                         escaped++;
 374                 if (strncmp(line, "----", 4) == 0 ||
 375                     strstr(line, ": ") != NULL) {
 376                         if (strstr(line, SSH_COM_PRIVATE_BEGIN) != NULL)
 377                                 private = 1;
 378                         if (strstr(line, " END ") != NULL) {
 379                                 break;
 380                         }
 381                         /* fprintf(stderr, "ignore: %s", line); */
 382                         continue;
 383                 }
 384                 if (escaped) {
 385                         escaped--;
 386                         /* fprintf(stderr, "escaped: %s", line); */
 387                         continue;
 388                 }
 389                 strlcat(encoded, line, sizeof(encoded));
 390         }
 391         len = strlen(encoded);
 392         if (((len % 4) == 3) &&
 393             (encoded[len-1] == '=') &&
 394             (encoded[len-2] == '=') &&
 395             (encoded[len-3] == '='))
 396                 encoded[len-3] = '\0';
 397         blen = uudecode(encoded, blob, sizeof(blob));
 398         if (blen < 0) {
 399                 fprintf(stderr, "uudecode failed.\n");
 400                 exit(1);
 401         }
 402         k = private ?
 403             do_convert_private_ssh2_from_blob(blob, blen) :
 404             key_from_blob(blob, blen);
 405         if (k == NULL) {
 406                 fprintf(stderr, "decode blob failed.\n");
 407                 exit(1);
 408         }
 409         ok = private ?
 410             (k->type == KEY_DSA ?
 411                  PEM_write_DSAPrivateKey(stdout, k->dsa, NULL, NULL, 0, NULL, NULL) :
 412                  PEM_write_RSAPrivateKey(stdout, k->rsa, NULL, NULL, 0, NULL, NULL)) :
 413             key_write(k, stdout);
 414         if (!ok) {
 415                 fprintf(stderr, "key write failed");
 416                 exit(1);
 417         }
 418         key_free(k);
 419         if (!private)
 420                 fprintf(stdout, "\n");
 421         fclose(fp);
 422         exit(0);
 423 }
 424
 425 static void
 426 do_print_public(struct passwd *pw)
 427 {
 428         Key *prv;
 429         struct stat st;
 430
 431         if (!have_identity)
 432                 ask_filename(pw, "Enter file in which the key is");
 433         if (stat(identity_file, &st) < 0) {
 434                 perror(identity_file);
 435                 exit(1);
 436         }
 437         prv = load_identity(identity_file);
 438         if (prv == NULL) {
 439                 fprintf(stderr, "load failed\n");
 440                 exit(1);
 441         }
 442         if (!key_write(prv, stdout))
 443                 fprintf(stderr, "key_write failed");
 444         key_free(prv);
 445         fprintf(stdout, "\n");
 446         exit(0);
 447 }
 448
 449 #ifdef SMARTCARD
 450 static void
 451 do_upload(struct passwd *pw, const char *sc_reader_id)
 452 {
 453         Key *prv = NULL;
 454         struct stat st;
 455         int ret;
 456
 457         if (!have_identity)
 458                 ask_filename(pw, "Enter file in which the key is");
 459         if (stat(identity_file, &st) < 0) {
 460                 perror(identity_file);
 461                 exit(1);
 462         }
 463         prv = load_identity(identity_file);
 464         if (prv == NULL) {
 465                 error("load failed");
 466                 exit(1);
 467         }
 468         ret = sc_put_key(prv, sc_reader_id);
 469         key_free(prv);
 470         if (ret < 0)
 471                 exit(1);
 472         logit("loading key done");
 473         exit(0);
 474 }
 475
 476 static void
 477 do_download(struct passwd *pw, const char *sc_reader_id)
 478 {
 479         Key **keys = NULL;
 480         int i;
 481
 482         keys = sc_get_keys(sc_reader_id, NULL);
 483         if (keys == NULL)
 484                 fatal("cannot read public key from smartcard");
 485         for (i = 0; keys[i]; i++) {
 486                 key_write(keys[i], stdout);
 487                 key_free(keys[i]);
 488                 fprintf(stdout, "\n");
 489         }
 490         xfree(keys);
 491         exit(0);
 492 }
 493 #endif /* SMARTCARD */
 494
 495 static void
 496 do_fingerprint(struct passwd *pw)
 497 {
 498         FILE *f;
 499         Key *public;
 500         char *comment = NULL, *cp, *ep, line[16*1024], *fp;
 501         int i, skip = 0, num = 1, invalid = 1;
 502         enum fp_rep rep;
 503         enum fp_type fptype;
 504         struct stat st;
 505
 506         fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
 507         rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
 508
 509         if (!have_identity)
 510                 ask_filename(pw, "Enter file in which the key is");
 511         if (stat(identity_file, &st) < 0) {
 512                 perror(identity_file);
 513                 exit(1);
 514         }
 515         public = key_load_public(identity_file, &comment);
 516         if (public != NULL) {
 517                 fp = key_fingerprint(public, fptype, rep);
 518                 printf("%u %s %s\n", key_size(public), fp, comment);
 519                 key_free(public);
 520                 xfree(comment);
 521                 xfree(fp);
 522                 exit(0);
 523         }
 524         if (comment) {
 525                 xfree(comment);
 526                 comment = NULL;
 527         }
 528
 529         f = fopen(identity_file, "r");
 530         if (f != NULL) {
 531                 while (fgets(line, sizeof(line), f)) {
 532                         i = strlen(line) - 1;
 533                         if (line[i] != '\n') {
 534                                 error("line %d too long: %.40s...", num, line);
 535                                 skip = 1;
 536                                 continue;
 537                         }
 538                         num++;
 539                         if (skip) {
 540                                 skip = 0;
 541                                 continue;
 542                         }
 543                         line[i] = '\0';
 544
 545                         /* Skip leading whitespace, empty and comment lines. */
 546                         for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 547                                 ;
 548                         if (!*cp || *cp == '\n' || *cp == '#')
 549                                 continue ;
 550                         i = strtol(cp, &ep, 10);
 551                         if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
 552                                 int quoted = 0;
 553                                 comment = cp;
 554                                 for (; *cp && (quoted || (*cp != ' ' &&
 555                                     *cp != '\t')); cp++) {
 556                                         if (*cp == '\\' && cp[1] == '"')
 557                                                 cp++;   /* Skip both */
 558                                         else if (*cp == '"')
 559                                                 quoted = !quoted;
 560                                 }
 561                                 if (!*cp)
 562                                         continue;
 563                                 *cp++ = '\0';
 564                         }
 565                         ep = cp;
 566                         public = key_new(KEY_RSA1);
 567                         if (key_read(public, &cp) != 1) {
 568                                 cp = ep;
 569                                 key_free(public);
 570                                 public = key_new(KEY_UNSPEC);
 571                                 if (key_read(public, &cp) != 1) {
 572                                         key_free(public);
 573                                         continue;
 574                                 }
 575                         }
 576                         comment = *cp ? cp : comment;
 577                         fp = key_fingerprint(public, fptype, rep);
 578                         printf("%u %s %s\n", key_size(public), fp,
 579                             comment ? comment : "no comment");
 580                         xfree(fp);
 581                         key_free(public);
 582                         invalid = 0;
 583                 }
 584                 fclose(f);
 585         }
 586         if (invalid) {
 587                 printf("%s is not a public key file.\n", identity_file);
 588                 exit(1);
 589         }
 590         exit(0);
 591 }
 592
 593 static void
 594 print_host(FILE *f, char *name, Key *public, int hash)
 595 {
 596         if (hash && (name = host_hash(name, NULL, 0)) == NULL)
 597                 fatal("hash_host failed");
 598         fprintf(f, "%s ", name);
 599         if (!key_write(public, f))
 600                 fatal("key_write failed");
 601         fprintf(f, "\n");
 602 }
 603
 604 static void
 605 do_known_hosts(struct passwd *pw, const char *name)
 606 {
 607         FILE *in, *out = stdout;
 608         Key *public;
 609         char *cp, *cp2, *kp, *kp2;
 610         char line[16*1024], tmp[MAXPATHLEN], old[MAXPATHLEN];
 611         int c, i, skip = 0, inplace = 0, num = 0, invalid = 0, has_unhashed = 0;
 612
 613         if (!have_identity) {
 614                 cp = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
 615                 if (strlcpy(identity_file, cp, sizeof(identity_file)) >=
 616                     sizeof(identity_file))
 617                         fatal("Specified known hosts path too long");
 618                 xfree(cp);
 619                 have_identity = 1;
 620         }
 621         if ((in = fopen(identity_file, "r")) == NULL)
 622                 fatal("fopen: %s", strerror(errno));
 623
 624         /*
 625          * Find hosts goes to stdout, hash and deletions happen in-place
 626          * A corner case is ssh-keygen -HF foo, which should go to stdout
 627          */
 628         if (!find_host && (hash_hosts || delete_host)) {
 629                 if (strlcpy(tmp, identity_file, sizeof(tmp)) >= sizeof(tmp) ||
 630                     strlcat(tmp, ".XXXXXXXXXX", sizeof(tmp)) >= sizeof(tmp) ||
 631                     strlcpy(old, identity_file, sizeof(old)) >= sizeof(old) ||
 632                     strlcat(old, ".old", sizeof(old)) >= sizeof(old))
 633                         fatal("known_hosts path too long");
 634                 umask(077);
 635                 if ((c = mkstemp(tmp)) == -1)
 636                         fatal("mkstemp: %s", strerror(errno));
 637                 if ((out = fdopen(c, "w")) == NULL) {
 638                         c = errno;
 639                         unlink(tmp);
 640                         fatal("fdopen: %s", strerror(c));
 641                 }
 642                 inplace = 1;
 643         }
 644
 645         while (fgets(line, sizeof(line), in)) {
 646                 num++;
 647                 i = strlen(line) - 1;
 648                 if (line[i] != '\n') {
 649                         error("line %d too long: %.40s...", num, line);
 650                         skip = 1;
 651                         invalid = 1;
 652                         continue;
 653                 }
 654                 if (skip) {
 655                         skip = 0;
 656                         continue;
 657                 }
 658                 line[i] = '\0';
 659
 660                 /* Skip leading whitespace, empty and comment lines. */
 661                 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 662                         ;
 663                 if (!*cp || *cp == '\n' || *cp == '#') {
 664                         if (inplace)
 665                                 fprintf(out, "%s\n", cp);
 666                         continue;
 667                 }
 668                 /* Find the end of the host name portion. */
 669                 for (kp = cp; *kp && *kp != ' ' && *kp != '\t'; kp++)
 670                         ;
 671                 if (*kp == '\0' || *(kp + 1) == '\0') {
 672                         error("line %d missing key: %.40s...",
 673                             num, line);
 674                         invalid = 1;
 675                         continue;
 676                 }
 677                 *kp++ = '\0';
 678                 kp2 = kp;
 679
 680                 public = key_new(KEY_RSA1);
 681                 if (key_read(public, &kp) != 1) {
 682                         kp = kp2;
 683                         key_free(public);
 684                         public = key_new(KEY_UNSPEC);
 685                         if (key_read(public, &kp) != 1) {
 686                                 error("line %d invalid key: %.40s...",
 687                                     num, line);
 688                                 key_free(public);
 689                                 invalid = 1;
 690                                 continue;
 691                         }
 692                 }
 693
 694                 if (*cp == HASH_DELIM) {
 695                         if (find_host || delete_host) {
 696                                 cp2 = host_hash(name, cp, strlen(cp));
 697                                 if (cp2 == NULL) {
 698                                         error("line %d: invalid hashed "
 699                                             "name: %.64s...", num, line);
 700                                         invalid = 1;
 701                                         continue;
 702                                 }
 703                                 c = (strcmp(cp2, cp) == 0);
 704                                 if (find_host && c) {
 705                                         printf("# Host %s found: "
 706                                             "line %d type %s\n", name,
 707                                             num, key_type(public));
 708                                         print_host(out, cp, public, 0);
 709                                 }
 710                                 if (delete_host && !c)
 711                                         print_host(out, cp, public, 0);
 712                         } else if (hash_hosts)
 713                                 print_host(out, cp, public, 0);
 714                 } else {
 715                         if (find_host || delete_host) {
 716                                 c = (match_hostname(name, cp,
 717                                     strlen(cp)) == 1);
 718                                 if (find_host && c) {
 719                                         printf("# Host %s found: "
 720                                             "line %d type %s\n", name,
 721                                             num, key_type(public));
 722                                         print_host(out, cp, public, hash_hosts);
 723                                 }
 724                                 if (delete_host && !c)
 725                                         print_host(out, cp, public, 0);
 726                         } else if (hash_hosts) {
 727                                 for (cp2 = strsep(&cp, ",");
 728                                     cp2 != NULL && *cp2 != '\0';
 729                                     cp2 = strsep(&cp, ",")) {
 730                                         if (strcspn(cp2, "*?!") != strlen(cp2))
 731                                                 fprintf(stderr, "Warning: "
 732                                                     "ignoring host name with "
 733                                                     "metacharacters: %.64s\n",
 734                                                     cp2);
 735                                         else
 736                                                 print_host(out, cp2, public, 1);
 737                                 }
 738                                 has_unhashed = 1;
 739                         }
 740                 }
 741                 key_free(public);
 742         }
 743         fclose(in);
 744
 745         if (invalid) {
 746                 fprintf(stderr, "%s is not a valid known_host file.\n",
 747                     identity_file);
 748                 if (inplace) {
 749                         fprintf(stderr, "Not replacing existing known_hosts "
 750                             "file because of errors\n");
 751                         fclose(out);
 752                         unlink(tmp);
 753                 }
 754                 exit(1);
 755         }
 756
 757         if (inplace) {
 758                 fclose(out);
 759
 760                 /* Backup existing file */
 761                 if (unlink(old) == -1 && errno != ENOENT)
 762                         fatal("unlink %.100s: %s", old, strerror(errno));
 763                 if (link(identity_file, old) == -1)
 764                         fatal("link %.100s to %.100s: %s", identity_file, old,
 765                             strerror(errno));
 766                 /* Move new one into place */
 767                 if (rename(tmp, identity_file) == -1) {
 768                         error("rename\"%s\" to \"%s\": %s", tmp, identity_file,
 769                             strerror(errno));
 770                         unlink(tmp);
 771                         unlink(old);
 772                         exit(1);
 773                 }
 774
 775                 fprintf(stderr, "%s updated.\n", identity_file);
 776                 fprintf(stderr, "Original contents retained as %s\n", old);
 777                 if (has_unhashed) {
 778                         fprintf(stderr, "WARNING: %s contains unhashed "
 779                             "entries\n", old);
 780                         fprintf(stderr, "Delete this file to ensure privacy "
 781                             "of hostnames\n");
 782                 }
 783         }
 784
 785         exit(0);
 786 }
 787
 788 /*
 789  * Perform changing a passphrase.  The argument is the passwd structure
 790  * for the current user.
 791  */
 792 static void
 793 do_change_passphrase(struct passwd *pw)
 794 {
 795         char *comment;
 796         char *old_passphrase, *passphrase1, *passphrase2;
 797         struct stat st;
 798         Key *private;
 799
 800         if (!have_identity)
 801                 ask_filename(pw, "Enter file in which the key is");
 802         if (stat(identity_file, &st) < 0) {
 803                 perror(identity_file);
 804                 exit(1);
 805         }
 806         /* Try to load the file with empty passphrase. */
 807         private = key_load_private(identity_file, "", &comment);
 808         if (private == NULL) {
 809                 if (identity_passphrase)
 810                         old_passphrase = xstrdup(identity_passphrase);
 811                 else
 812                         old_passphrase =
 813                             read_passphrase("Enter old passphrase: ",
 814                             RP_ALLOW_STDIN);
 815                 private = key_load_private(identity_file, old_passphrase,
 816                     &comment);
 817                 memset(old_passphrase, 0, strlen(old_passphrase));
 818                 xfree(old_passphrase);
 819                 if (private == NULL) {
 820                         printf("Bad passphrase.\n");
 821                         exit(1);
 822                 }
 823         }
 824         printf("Key has comment '%s'\n", comment);
 825
 826         /* Ask the new passphrase (twice). */
 827         if (identity_new_passphrase) {
 828                 passphrase1 = xstrdup(identity_new_passphrase);
 829                 passphrase2 = NULL;
 830         } else {
 831                 passphrase1 =
 832                         read_passphrase("Enter new passphrase (empty for no "
 833                             "passphrase): ", RP_ALLOW_STDIN);
 834                 passphrase2 = read_passphrase("Enter same passphrase again: ",
 835                     RP_ALLOW_STDIN);
 836
 837                 /* Verify that they are the same. */
 838                 if (strcmp(passphrase1, passphrase2) != 0) {
 839                         memset(passphrase1, 0, strlen(passphrase1));
 840                         memset(passphrase2, 0, strlen(passphrase2));
 841                         xfree(passphrase1);
 842                         xfree(passphrase2);
 843                         printf("Pass phrases do not match.  Try again.\n");
 844                         exit(1);
 845                 }
 846                 /* Destroy the other copy. */
 847                 memset(passphrase2, 0, strlen(passphrase2));
 848                 xfree(passphrase2);
 849         }
 850
 851         /* Save the file using the new passphrase. */
 852         if (!key_save_private(private, identity_file, passphrase1, comment)) {
 853                 printf("Saving the key failed: %s.\n", identity_file);
 854                 memset(passphrase1, 0, strlen(passphrase1));
 855                 xfree(passphrase1);
 856                 key_free(private);
 857                 xfree(comment);
 858                 exit(1);
 859         }
 860         /* Destroy the passphrase and the copy of the key in memory. */
 861         memset(passphrase1, 0, strlen(passphrase1));
 862         xfree(passphrase1);
 863         key_free(private);               /* Destroys contents */
 864         xfree(comment);
 865
 866         printf("Your identification has been saved with the new passphrase.\n");
 867         exit(0);
 868 }
 869
 870 /*
 871  * Print the SSHFP RR.
 872  */
 873 static int
 874 do_print_resource_record(struct passwd *pw, char *fname, char *hname)
 875 {
 876         Key *public;
 877         char *comment = NULL;
 878         struct stat st;
 879
 880         if (fname == NULL)
 881                 ask_filename(pw, "Enter file in which the key is");
 882         if (stat(fname, &st) < 0) {
 883                 if (errno == ENOENT)
 884                         return 0;
 885                 perror(fname);
 886                 exit(1);
 887         }
 888         public = key_load_public(fname, &comment);
 889         if (public != NULL) {
 890                 export_dns_rr(hname, public, stdout, print_generic);
 891                 key_free(public);
 892                 xfree(comment);
 893                 return 1;
 894         }
 895         if (comment)
 896                 xfree(comment);
 897
 898         printf("failed to read v2 public key from %s.\n", fname);
 899         exit(1);
 900 }
 901
 902 /*
 903  * Change the comment of a private key file.
 904  */
 905 static void
 906 do_change_comment(struct passwd *pw)
 907 {
 908         char new_comment[1024], *comment, *passphrase;
 909         Key *private;
 910         Key *public;
 911         struct stat st;
 912         FILE *f;
 913         int fd;
 914
 915         if (!have_identity)
 916                 ask_filename(pw, "Enter file in which the key is");
 917         if (stat(identity_file, &st) < 0) {
 918                 perror(identity_file);
 919                 exit(1);
 920         }
 921         private = key_load_private(identity_file, "", &comment);
 922         if (private == NULL) {
 923                 if (identity_passphrase)
 924                         passphrase = xstrdup(identity_passphrase);
 925                 else if (identity_new_passphrase)
 926                         passphrase = xstrdup(identity_new_passphrase);
 927                 else
 928                         passphrase = read_passphrase("Enter passphrase: ",
 929                             RP_ALLOW_STDIN);
 930                 /* Try to load using the passphrase. */
 931                 private = key_load_private(identity_file, passphrase, &comment);
 932                 if (private == NULL) {
 933                         memset(passphrase, 0, strlen(passphrase));
 934                         xfree(passphrase);
 935                         printf("Bad passphrase.\n");
 936                         exit(1);
 937                 }
 938         } else {
 939                 passphrase = xstrdup("");
 940         }
 941         if (private->type != KEY_RSA1) {
 942                 fprintf(stderr, "Comments are only supported for RSA1 keys.\n");
 943                 key_free(private);
 944                 exit(1);
 945         }
 946         printf("Key now has comment '%s'\n", comment);
 947
 948         if (identity_comment) {
 949                 strlcpy(new_comment, identity_comment, sizeof(new_comment));
 950         } else {
 951                 printf("Enter new comment: ");
 952                 fflush(stdout);
 953                 if (!fgets(new_comment, sizeof(new_comment), stdin)) {
 954                         memset(passphrase, 0, strlen(passphrase));
 955                         key_free(private);
 956                         exit(1);
 957                 }
 958                 if (strchr(new_comment, '\n'))
 959                         *strchr(new_comment, '\n') = 0;
 960         }
 961
 962         /* Save the file using the new passphrase. */
 963         if (!key_save_private(private, identity_file, passphrase, new_comment)) {
 964                 printf("Saving the key failed: %s.\n", identity_file);
 965                 memset(passphrase, 0, strlen(passphrase));
 966                 xfree(passphrase);
 967                 key_free(private);
 968                 xfree(comment);
 969                 exit(1);
 970         }
 971         memset(passphrase, 0, strlen(passphrase));
 972         xfree(passphrase);
 973         public = key_from_private(private);
 974         key_free(private);
 975
 976         strlcat(identity_file, ".pub", sizeof(identity_file));
 977         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 978         if (fd == -1) {
 979                 printf("Could not save your public key in %s\n", identity_file);
 980                 exit(1);
 981         }
 982         f = fdopen(fd, "w");
 983         if (f == NULL) {
 984                 printf("fdopen %s failed", identity_file);
 985                 exit(1);
 986         }
 987         if (!key_write(public, f))
 988                 fprintf(stderr, "write key failed");
 989         key_free(public);
 990         fprintf(f, " %s\n", new_comment);
 991         fclose(f);
 992
 993         xfree(comment);
 994
 995         printf("The comment in your key file has been changed.\n");
 996         exit(0);
 997 }
 998
 999 static void
1000 usage(void)
1001 {
1002         fprintf(stderr, "Usage: %s [options]\n", __progname);
1003         fprintf(stderr, "Options:\n");
1004         fprintf(stderr, "  -a trials   Number of trials for screening DH-GEX moduli.\n");
1005         fprintf(stderr, "  -B          Show bubblebabble digest of key file.\n");
1006         fprintf(stderr, "  -b bits     Number of bits in the key to create.\n");
1007         fprintf(stderr, "  -C comment  Provide new comment.\n");
1008         fprintf(stderr, "  -c          Change comment in private and public key files.\n");
1009 #ifdef SMARTCARD
1010         fprintf(stderr, "  -D reader   Download public key from smartcard.\n");
1011 #endif /* SMARTCARD */
1012         fprintf(stderr, "  -e          Convert OpenSSH to IETF SECSH key file.\n");
1013         fprintf(stderr, "  -F hostname Find hostname in known hosts file.\n");
1014         fprintf(stderr, "  -f filename Filename of the key file.\n");
1015         fprintf(stderr, "  -G file     Generate candidates for DH-GEX moduli.\n");
1016         fprintf(stderr, "  -g          Use generic DNS resource record format.\n");
1017         fprintf(stderr, "  -H          Hash names in known_hosts file.\n");
1018         fprintf(stderr, "  -i          Convert IETF SECSH to OpenSSH key file.\n");
1019         fprintf(stderr, "  -l          Show fingerprint of key file.\n");
1020         fprintf(stderr, "  -M memory   Amount of memory (MB) to use for generating DH-GEX moduli.\n");
1021         fprintf(stderr, "  -N phrase   Provide new passphrase.\n");
1022         fprintf(stderr, "  -P phrase   Provide old passphrase.\n");
1023         fprintf(stderr, "  -p          Change passphrase of private key file.\n");
1024         fprintf(stderr, "  -q          Quiet.\n");
1025         fprintf(stderr, "  -R hostname Remove host from known_hosts file.\n");
1026         fprintf(stderr, "  -r hostname Print DNS resource record.\n");
1027         fprintf(stderr, "  -S start    Start point (hex) for generating DH-GEX moduli.\n");
1028         fprintf(stderr, "  -T file     Screen candidates for DH-GEX moduli.\n");
1029         fprintf(stderr, "  -t type     Specify type of key to create.\n");
1030 #ifdef SMARTCARD
1031         fprintf(stderr, "  -U reader   Upload private key to smartcard.\n");
1032 #endif /* SMARTCARD */
1033         fprintf(stderr, "  -v          Verbose.\n");
1034         fprintf(stderr, "  -W gen      Generator to use for generating DH-GEX moduli.\n");
1035         fprintf(stderr, "  -y          Read private key file and print public key.\n");
1036
1037         exit(1);
1038 }
1039
1040 /*
1041  * Main program for key management.
1042  */
1043 int
1044 main(int ac, char **av)
1045 {
1046         char dotsshdir[MAXPATHLEN], comment[1024], *passphrase1, *passphrase2;
1047         char out_file[MAXPATHLEN], *reader_id = NULL;
1048         char *rr_hostname = NULL;
1049         Key *private, *public;
1050         struct passwd *pw;
1051         struct stat st;
1052         int opt, type, fd, download = 0;
1053         u_int32_t memory = 0, generator_wanted = 0, trials = 100;
1054         int do_gen_candidates = 0, do_screen_candidates = 0;
1055         int log_level = SYSLOG_LEVEL_INFO;
1056         BIGNUM *start = NULL;
1057         FILE *f;
1058         const char *errstr;
1059
1060         extern int optind;
1061         extern char *optarg;
1062
1063         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1064         sanitise_stdfd();
1065
1066         __progname = ssh_get_progname(av[0]);
1067
1068         SSLeay_add_all_algorithms();
1069         log_init(av[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
1070
1071         init_rng();
1072         seed_rng();
1073
1074         /* we need this for the home * directory.  */
1075         pw = getpwuid(getuid());
1076         if (!pw) {
1077                 printf("You don't exist, go away!\n");
1078                 exit(1);
1079         }
1080         if (gethostname(hostname, sizeof(hostname)) < 0) {
1081                 perror("gethostname");
1082                 exit(1);
1083         }
1084
1085         while ((opt = getopt(ac, av,
1086             "degiqpclBHvxXyF:b:f:t:U:D:P:N:C:r:g:R:T:G:M:S:a:W:")) != -1) {
1087                 switch (opt) {
1088                 case 'b':
1089                         bits = (u_int32_t)strtonum(optarg, 768, 32768, &errstr);
1090                         if (errstr)
1091                                 fatal("Bits has bad value %s (%s)",
1092                                         optarg, errstr);
1093                         break;
1094                 case 'F':
1095                         find_host = 1;
1096                         rr_hostname = optarg;
1097                         break;
1098                 case 'H':
1099                         hash_hosts = 1;
1100                         break;
1101                 case 'R':
1102                         delete_host = 1;
1103                         rr_hostname = optarg;
1104                         break;
1105                 case 'l':
1106                         print_fingerprint = 1;
1107                         break;
1108                 case 'B':
1109                         print_bubblebabble = 1;
1110                         break;
1111                 case 'p':
1112                         change_passphrase = 1;
1113                         break;
1114                 case 'c':
1115                         change_comment = 1;
1116                         break;
1117                 case 'f':
1118                         if (strlcpy(identity_file, optarg, sizeof(identity_file)) >=
1119                             sizeof(identity_file))
1120                                 fatal("Identity filename too long");
1121                         have_identity = 1;
1122                         break;
1123                 case 'g':
1124                         print_generic = 1;
1125                         break;
1126                 case 'P':
1127                         identity_passphrase = optarg;
1128                         break;
1129                 case 'N':
1130                         identity_new_passphrase = optarg;
1131                         break;
1132                 case 'C':
1133                         identity_comment = optarg;
1134                         break;
1135                 case 'q':
1136                         quiet = 1;
1137                         break;
1138                 case 'e':
1139                 case 'x':
1140                         /* export key */
1141                         convert_to_ssh2 = 1;
1142                         break;
1143                 case 'i':
1144                 case 'X':
1145                         /* import key */
1146                         convert_from_ssh2 = 1;
1147                         break;
1148                 case 'y':
1149                         print_public = 1;
1150                         break;
1151                 case 'd':
1152                         key_type_name = "dsa";
1153                         break;
1154                 case 't':
1155                         key_type_name = optarg;
1156                         break;
1157                 case 'D':
1158                         download = 1;
1159                         /*FALLTHROUGH*/
1160                 case 'U':
1161                         reader_id = optarg;
1162                         break;
1163                 case 'v':
1164                         if (log_level == SYSLOG_LEVEL_INFO)
1165                                 log_level = SYSLOG_LEVEL_DEBUG1;
1166                         else {
1167                                 if (log_level >= SYSLOG_LEVEL_DEBUG1 &&
1168                                     log_level < SYSLOG_LEVEL_DEBUG3)
1169                                         log_level++;
1170                         }
1171                         break;
1172                 case 'r':
1173                         rr_hostname = optarg;
1174                         break;
1175                 case 'W':
1176                         generator_wanted = (u_int32_t)strtonum(optarg, 1,
1177                             UINT_MAX, &errstr);
1178                         if (errstr)
1179                                 fatal("Desired generator has bad value: %s (%s)",
1180                                         optarg, errstr);
1181                         break;
1182                 case 'a':
1183                         trials = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1184                         if (errstr)
1185                                 fatal("Invalid number of trials: %s (%s)",
1186                                         optarg, errstr);
1187                         break;
1188                 case 'M':
1189                         memory = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1190                         if (errstr) {
1191                                 fatal("Memory limit is %s: %s", errstr, optarg);
1192                         }
1193                         break;
1194                 case 'G':
1195                         do_gen_candidates = 1;
1196                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1197                             sizeof(out_file))
1198                                 fatal("Output filename too long");
1199                         break;
1200                 case 'T':
1201                         do_screen_candidates = 1;
1202                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1203                             sizeof(out_file))
1204                                 fatal("Output filename too long");
1205                         break;
1206                 case 'S':
1207                         /* XXX - also compare length against bits */
1208                         if (BN_hex2bn(&start, optarg) == 0)
1209                                 fatal("Invalid start point.");
1210                         break;
1211                 case '?':
1212                 default:
1213                         usage();
1214                 }
1215         }
1216
1217         /* reinit */
1218         log_init(av[0], log_level, SYSLOG_FACILITY_USER, 1);
1219
1220         if (optind < ac) {
1221                 printf("Too many arguments.\n");
1222                 usage();
1223         }
1224         if (change_passphrase && change_comment) {
1225                 printf("Can only have one of -p and -c.\n");
1226                 usage();
1227         }
1228         if (delete_host || hash_hosts || find_host)
1229                 do_known_hosts(pw, rr_hostname);
1230         if (print_fingerprint || print_bubblebabble)
1231                 do_fingerprint(pw);
1232         if (change_passphrase)
1233                 do_change_passphrase(pw);
1234         if (change_comment)
1235                 do_change_comment(pw);
1236         if (convert_to_ssh2)
1237                 do_convert_to_ssh2(pw);
1238         if (convert_from_ssh2)
1239                 do_convert_from_ssh2(pw);
1240         if (print_public)
1241                 do_print_public(pw);
1242         if (rr_hostname != NULL) {
1243                 unsigned int n = 0;
1244
1245                 if (have_identity) {
1246                         n = do_print_resource_record(pw,
1247                             identity_file, rr_hostname);
1248                         if (n == 0) {
1249                                 perror(identity_file);
1250                                 exit(1);
1251                         }
1252                         exit(0);
1253                 } else {
1254
1255                         n += do_print_resource_record(pw,
1256                             _PATH_HOST_RSA_KEY_FILE, rr_hostname);
1257                         n += do_print_resource_record(pw,
1258                             _PATH_HOST_DSA_KEY_FILE, rr_hostname);
1259
1260                         if (n == 0)
1261                                 fatal("no keys found.");
1262                         exit(0);
1263                 }
1264         }
1265         if (reader_id != NULL) {
1266 #ifdef SMARTCARD
1267                 if (download)
1268                         do_download(pw, reader_id);
1269                 else
1270                         do_upload(pw, reader_id);
1271 #else /* SMARTCARD */
1272                 fatal("no support for smartcards.");
1273 #endif /* SMARTCARD */
1274         }
1275
1276         if (do_gen_candidates) {
1277                 FILE *out = fopen(out_file, "w");
1278
1279                 if (out == NULL) {
1280                         error("Couldn't open modulus candidate file \"%s\": %s",
1281                             out_file, strerror(errno));
1282                         return (1);
1283                 }
1284                 if (bits == 0)
1285                         bits = DEFAULT_BITS;
1286                 if (gen_candidates(out, memory, bits, start) != 0)
1287                         fatal("modulus candidate generation failed");
1288
1289                 return (0);
1290         }
1291
1292         if (do_screen_candidates) {
1293                 FILE *in;
1294                 FILE *out = fopen(out_file, "w");
1295
1296                 if (have_identity && strcmp(identity_file, "-") != 0) {
1297                         if ((in = fopen(identity_file, "r")) == NULL) {
1298                                 fatal("Couldn't open modulus candidate "
1299                                     "file \"%s\": %s", identity_file,
1300                                     strerror(errno));
1301                         }
1302                 } else
1303                         in = stdin;
1304
1305                 if (out == NULL) {
1306                         fatal("Couldn't open moduli file \"%s\": %s",
1307                             out_file, strerror(errno));
1308                 }
1309                 if (prime_test(in, out, trials, generator_wanted) != 0)
1310                         fatal("modulus screening failed");
1311                 return (0);
1312         }
1313
1314         arc4random_stir();
1315
1316         if (key_type_name == NULL)
1317                 key_type_name = "rsa";
1318
1319         type = key_type_from_name(key_type_name);
1320         if (type == KEY_UNSPEC) {
1321                 fprintf(stderr, "unknown key type %s\n", key_type_name);
1322                 exit(1);
1323         }
1324         if (bits == 0)
1325                 bits = (type == KEY_DSA) ? DEFAULT_BITS_DSA : DEFAULT_BITS;
1326         if (type == KEY_DSA && bits != 1024)
1327                 fatal("DSA keys must be 1024 bits");
1328         if (!quiet)
1329                 printf("Generating public/private %s key pair.\n", key_type_name);
1330         private = key_generate(type, bits);
1331         if (private == NULL) {
1332                 fprintf(stderr, "key_generate failed");
1333                 exit(1);
1334         }
1335         public  = key_from_private(private);
1336
1337         if (!have_identity)
1338                 ask_filename(pw, "Enter file in which to save the key");
1339
1340         /* Create ~/.ssh directory if it doesn't already exist. */
1341         snprintf(dotsshdir, sizeof dotsshdir, "%s/%s", pw->pw_dir, _PATH_SSH_USER_DIR);
1342         if (strstr(identity_file, dotsshdir) != NULL &&
1343             stat(dotsshdir, &st) < 0) {
1344                 if (mkdir(dotsshdir, 0700) < 0)
1345                         error("Could not create directory '%s'.", dotsshdir);
1346                 else if (!quiet)
1347                         printf("Created directory '%s'.\n", dotsshdir);
1348         }
1349         /* If the file already exists, ask the user to confirm. */
1350         if (stat(identity_file, &st) >= 0) {
1351                 char yesno[3];
1352                 printf("%s already exists.\n", identity_file);
1353                 printf("Overwrite (y/n)? ");
1354                 fflush(stdout);
1355                 if (fgets(yesno, sizeof(yesno), stdin) == NULL)
1356                         exit(1);
1357                 if (yesno[0] != 'y' && yesno[0] != 'Y')
1358                         exit(1);
1359         }
1360         /* Ask for a passphrase (twice). */
1361         if (identity_passphrase)
1362                 passphrase1 = xstrdup(identity_passphrase);
1363         else if (identity_new_passphrase)
1364                 passphrase1 = xstrdup(identity_new_passphrase);
1365         else {
1366 passphrase_again:
1367                 passphrase1 =
1368                         read_passphrase("Enter passphrase (empty for no "
1369                             "passphrase): ", RP_ALLOW_STDIN);
1370                 passphrase2 = read_passphrase("Enter same passphrase again: ",
1371                     RP_ALLOW_STDIN);
1372                 if (strcmp(passphrase1, passphrase2) != 0) {
1373                         /*
1374                          * The passphrases do not match.  Clear them and
1375                          * retry.
1376                          */
1377                         memset(passphrase1, 0, strlen(passphrase1));
1378                         memset(passphrase2, 0, strlen(passphrase2));
1379                         xfree(passphrase1);
1380                         xfree(passphrase2);
1381                         printf("Passphrases do not match.  Try again.\n");
1382                         goto passphrase_again;
1383                 }
1384                 /* Clear the other copy of the passphrase. */
1385                 memset(passphrase2, 0, strlen(passphrase2));
1386                 xfree(passphrase2);
1387         }
1388
1389         if (identity_comment) {
1390                 strlcpy(comment, identity_comment, sizeof(comment));
1391         } else {
1392                 /* Create default commend field for the passphrase. */
1393                 snprintf(comment, sizeof comment, "%s@%s", pw->pw_name, hostname);
1394         }
1395
1396         /* Save the key with the given passphrase and comment. */
1397         if (!key_save_private(private, identity_file, passphrase1, comment)) {
1398                 printf("Saving the key failed: %s.\n", identity_file);
1399                 memset(passphrase1, 0, strlen(passphrase1));
1400                 xfree(passphrase1);
1401                 exit(1);
1402         }
1403         /* Clear the passphrase. */
1404         memset(passphrase1, 0, strlen(passphrase1));
1405         xfree(passphrase1);
1406
1407         /* Clear the private key and the random number generator. */
1408         key_free(private);
1409         arc4random_stir();
1410
1411         if (!quiet)
1412                 printf("Your identification has been saved in %s.\n", identity_file);
1413
1414         strlcat(identity_file, ".pub", sizeof(identity_file));
1415         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
1416         if (fd == -1) {
1417                 printf("Could not save your public key in %s\n", identity_file);
1418                 exit(1);
1419         }
1420         f = fdopen(fd, "w");
1421         if (f == NULL) {
1422                 printf("fdopen %s failed", identity_file);
1423                 exit(1);
1424         }
1425         if (!key_write(public, f))
1426                 fprintf(stderr, "write key failed");
1427         fprintf(f, " %s\n", comment);
1428         fclose(f);
1429
1430         if (!quiet) {
1431                 char *fp = key_fingerprint(public, SSH_FP_MD5, SSH_FP_HEX);
1432                 printf("Your public key has been saved in %s.\n",
1433                     identity_file);
1434                 printf("The key fingerprint is:\n");
1435                 printf("%s %s\n", fp, comment);
1436                 xfree(fp);
1437         }
1438
1439         key_free(public);
1440         exit(0);
1441 }