ssh-keygen.c

   1 /* $OpenBSD: ssh-keygen.c,v 1.142 2006/03/25 18:40:14 deraadt 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 "xmalloc.h"
  24 #include "key.h"
  25 #include "rsa.h"
  26 #include "authfile.h"
  27 #include "uuencode.h"
  28 #include "buffer.h"
  29 #include "bufaux.h"
  30 #include "pathnames.h"
  31 #include "log.h"
  32 #include "misc.h"
  33 #include "match.h"
  34 #include "hostfile.h"
  35
  36 #ifdef SMARTCARD
  37 #include "scard.h"
  38 #endif
  39 #include "dns.h"
  40
  41 /* Number of bits in the RSA/DSA key.  This value can be set on the command line. */
  42 #define DEFAULT_BITS            2048
  43 #define DEFAULT_BITS_DSA        1024
  44 u_int32_t bits = 0;
  45
  46 /*
  47  * Flag indicating that we just want to change the passphrase.  This can be
  48  * set on the command line.
  49  */
  50 int change_passphrase = 0;
  51
  52 /*
  53  * Flag indicating that we just want to change the comment.  This can be set
  54  * on the command line.
  55  */
  56 int change_comment = 0;
  57
  58 int quiet = 0;
  59
  60 /* Flag indicating that we want to hash a known_hosts file */
  61 int hash_hosts = 0;
  62 /* Flag indicating that we want lookup a host in known_hosts file */
  63 int find_host = 0;
  64 /* Flag indicating that we want to delete a host from a known_hosts file */
  65 int delete_host = 0;
  66
  67 /* Flag indicating that we just want to see the key fingerprint */
  68 int print_fingerprint = 0;
  69 int print_bubblebabble = 0;
  70
  71 /* The identity file name, given on the command line or entered by the user. */
  72 char identity_file[1024];
  73 int have_identity = 0;
  74
  75 /* This is set to the passphrase if given on the command line. */
  76 char *identity_passphrase = NULL;
  77
  78 /* This is set to the new passphrase if given on the command line. */
  79 char *identity_new_passphrase = NULL;
  80
  81 /* This is set to the new comment if given on the command line. */
  82 char *identity_comment = NULL;
  83
  84 /* Dump public key file in format used by real and the original SSH 2 */
  85 int convert_to_ssh2 = 0;
  86 int convert_from_ssh2 = 0;
  87 int print_public = 0;
  88 int print_generic = 0;
  89
  90 char *key_type_name = NULL;
  91
  92 /* argv0 */
  93 extern char *__progname;
  94
  95 char hostname[MAXHOSTNAMELEN];
  96
  97 /* moduli.c */
  98 int gen_candidates(FILE *, u_int32_t, u_int32_t, BIGNUM *);
  99 int prime_test(FILE *, FILE *, u_int32_t, u_int32_t);
 100
 101 static void
 102 ask_filename(struct passwd *pw, const char *prompt)
 103 {
 104         char buf[1024];
 105         char *name = NULL;
 106
 107         if (key_type_name == NULL)
 108                 name = _PATH_SSH_CLIENT_ID_RSA;
 109         else {
 110                 switch (key_type_from_name(key_type_name)) {
 111                 case KEY_RSA1:
 112                         name = _PATH_SSH_CLIENT_IDENTITY;
 113                         break;
 114                 case KEY_DSA:
 115                         name = _PATH_SSH_CLIENT_ID_DSA;
 116                         break;
 117                 case KEY_RSA:
 118                         name = _PATH_SSH_CLIENT_ID_RSA;
 119                         break;
 120                 default:
 121                         fprintf(stderr, "bad key type");
 122                         exit(1);
 123                         break;
 124                 }
 125         }
 126         snprintf(identity_file, sizeof(identity_file), "%s/%s", pw->pw_dir, name);
 127         fprintf(stderr, "%s (%s): ", prompt, identity_file);
 128         if (fgets(buf, sizeof(buf), stdin) == NULL)
 129                 exit(1);
 130         if (strchr(buf, '\n'))
 131                 *strchr(buf, '\n') = 0;
 132         if (strcmp(buf, "") != 0)
 133                 strlcpy(identity_file, buf, sizeof(identity_file));
 134         have_identity = 1;
 135 }
 136
 137 static Key *
 138 load_identity(char *filename)
 139 {
 140         char *pass;
 141         Key *prv;
 142
 143         prv = key_load_private(filename, "", NULL);
 144         if (prv == NULL) {
 145                 if (identity_passphrase)
 146                         pass = xstrdup(identity_passphrase);
 147                 else
 148                         pass = read_passphrase("Enter passphrase: ",
 149                             RP_ALLOW_STDIN);
 150                 prv = key_load_private(filename, pass, NULL);
 151                 memset(pass, 0, strlen(pass));
 152                 xfree(pass);
 153         }
 154         return prv;
 155 }
 156
 157 #define SSH_COM_PUBLIC_BEGIN            "---- BEGIN SSH2 PUBLIC KEY ----"
 158 #define SSH_COM_PUBLIC_END              "---- END SSH2 PUBLIC KEY ----"
 159 #define SSH_COM_PRIVATE_BEGIN           "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----"
 160 #define SSH_COM_PRIVATE_KEY_MAGIC       0x3f6ff9eb
 161
 162 static void
 163 do_convert_to_ssh2(struct passwd *pw)
 164 {
 165         Key *k;
 166         u_int len;
 167         u_char *blob;
 168         struct stat st;
 169
 170         if (!have_identity)
 171                 ask_filename(pw, "Enter file in which the key is");
 172         if (stat(identity_file, &st) < 0) {
 173                 perror(identity_file);
 174                 exit(1);
 175         }
 176         if ((k = key_load_public(identity_file, NULL)) == NULL) {
 177                 if ((k = load_identity(identity_file)) == NULL) {
 178                         fprintf(stderr, "load failed\n");
 179                         exit(1);
 180                 }
 181         }
 182         if (k->type == KEY_RSA1) {
 183                 fprintf(stderr, "version 1 keys are not supported\n");
 184                 exit(1);
 185         }
 186         if (key_to_blob(k, &blob, &len) <= 0) {
 187                 fprintf(stderr, "key_to_blob failed\n");
 188                 exit(1);
 189         }
 190         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_BEGIN);
 191         fprintf(stdout,
 192             "Comment: \"%u-bit %s, converted from OpenSSH by %s@%s\"\n",
 193             key_size(k), key_type(k),
 194             pw->pw_name, hostname);
 195         dump_base64(stdout, blob, len);
 196         fprintf(stdout, "%s\n", SSH_COM_PUBLIC_END);
 197         key_free(k);
 198         xfree(blob);
 199         exit(0);
 200 }
 201
 202 static void
 203 buffer_get_bignum_bits(Buffer *b, BIGNUM *value)
 204 {
 205         u_int bignum_bits = buffer_get_int(b);
 206         u_int bytes = (bignum_bits + 7) / 8;
 207
 208         if (buffer_len(b) < bytes)
 209                 fatal("buffer_get_bignum_bits: input buffer too small: "
 210                     "need %d have %d", bytes, buffer_len(b));
 211         BN_bin2bn(buffer_ptr(b), bytes, value);
 212         buffer_consume(b, bytes);
 213 }
 214
 215 static Key *
 216 do_convert_private_ssh2_from_blob(u_char *blob, u_int blen)
 217 {
 218         Buffer b;
 219         Key *key = NULL;
 220         char *type, *cipher;
 221         u_char *sig, data[] = "abcde12345";
 222         int magic, rlen, ktype, i1, i2, i3, i4;
 223         u_int slen;
 224         u_long e;
 225
 226         buffer_init(&b);
 227         buffer_append(&b, blob, blen);
 228
 229         magic  = buffer_get_int(&b);
 230         if (magic != SSH_COM_PRIVATE_KEY_MAGIC) {
 231                 error("bad magic 0x%x != 0x%x", magic, SSH_COM_PRIVATE_KEY_MAGIC);
 232                 buffer_free(&b);
 233                 return NULL;
 234         }
 235         i1 = buffer_get_int(&b);
 236         type   = buffer_get_string(&b, NULL);
 237         cipher = buffer_get_string(&b, NULL);
 238         i2 = buffer_get_int(&b);
 239         i3 = buffer_get_int(&b);
 240         i4 = buffer_get_int(&b);
 241         debug("ignore (%d %d %d %d)", i1,i2,i3,i4);
 242         if (strcmp(cipher, "none") != 0) {
 243                 error("unsupported cipher %s", cipher);
 244                 xfree(cipher);
 245                 buffer_free(&b);
 246                 xfree(type);
 247                 return NULL;
 248         }
 249         xfree(cipher);
 250
 251         if (strstr(type, "dsa")) {
 252                 ktype = KEY_DSA;
 253         } else if (strstr(type, "rsa")) {
 254                 ktype = KEY_RSA;
 255         } else {
 256                 buffer_free(&b);
 257                 xfree(type);
 258                 return NULL;
 259         }
 260         key = key_new_private(ktype);
 261         xfree(type);
 262
 263         switch (key->type) {
 264         case KEY_DSA:
 265                 buffer_get_bignum_bits(&b, key->dsa->p);
 266                 buffer_get_bignum_bits(&b, key->dsa->g);
 267                 buffer_get_bignum_bits(&b, key->dsa->q);
 268                 buffer_get_bignum_bits(&b, key->dsa->pub_key);
 269                 buffer_get_bignum_bits(&b, key->dsa->priv_key);
 270                 break;
 271         case KEY_RSA:
 272                 e  = buffer_get_char(&b);
 273                 debug("e %lx", e);
 274                 if (e < 30) {
 275                         e <<= 8;
 276                         e += buffer_get_char(&b);
 277                         debug("e %lx", e);
 278                         e <<= 8;
 279                         e += buffer_get_char(&b);
 280                         debug("e %lx", e);
 281                 }
 282                 if (!BN_set_word(key->rsa->e, e)) {
 283                         buffer_free(&b);
 284                         key_free(key);
 285                         return NULL;
 286                 }
 287                 buffer_get_bignum_bits(&b, key->rsa->d);
 288                 buffer_get_bignum_bits(&b, key->rsa->n);
 289                 buffer_get_bignum_bits(&b, key->rsa->iqmp);
 290                 buffer_get_bignum_bits(&b, key->rsa->q);
 291                 buffer_get_bignum_bits(&b, key->rsa->p);
 292                 rsa_generate_additional_parameters(key->rsa);
 293                 break;
 294         }
 295         rlen = buffer_len(&b);
 296         if (rlen != 0)
 297                 error("do_convert_private_ssh2_from_blob: "
 298                     "remaining bytes in key blob %d", rlen);
 299         buffer_free(&b);
 300
 301         /* try the key */
 302         key_sign(key, &sig, &slen, data, sizeof(data));
 303         key_verify(key, sig, slen, data, sizeof(data));
 304         xfree(sig);
 305         return key;
 306 }
 307
 308 static int
 309 get_line(FILE *fp, char *line, size_t len)
 310 {
 311         int c;
 312         size_t pos = 0;
 313
 314         line[0] = '\0';
 315         while ((c = fgetc(fp)) != EOF) {
 316                 if (pos >= len - 1) {
 317                         fprintf(stderr, "input line too long.\n");
 318                         exit(1);
 319                 }
 320                 switch (c) {
 321                 case '\r':
 322                         c = fgetc(fp);
 323                         if (c != EOF && c != '\n' && ungetc(c, fp) == EOF) {
 324                                 fprintf(stderr, "unget: %s\n", strerror(errno));
 325                                 exit(1);
 326                         }
 327                         return pos;
 328                 case '\n':
 329                         return pos;
 330                 }
 331                 line[pos++] = c;
 332                 line[pos] = '\0';
 333         }
 334         return pos;
 335 }
 336
 337 static void
 338 do_convert_from_ssh2(struct passwd *pw)
 339 {
 340         Key *k;
 341         int blen;
 342         u_int len;
 343         char line[1024];
 344         u_char blob[8096];
 345         char encoded[8096];
 346         struct stat st;
 347         int escaped = 0, private = 0, ok;
 348         FILE *fp;
 349
 350         if (!have_identity)
 351                 ask_filename(pw, "Enter file in which the key is");
 352         if (stat(identity_file, &st) < 0) {
 353                 perror(identity_file);
 354                 exit(1);
 355         }
 356         fp = fopen(identity_file, "r");
 357         if (fp == NULL) {
 358                 perror(identity_file);
 359                 exit(1);
 360         }
 361         encoded[0] = '\0';
 362         while ((blen = get_line(fp, line, sizeof(line))) != -1) {
 363                 if (line[blen - 1] == '\\')
 364                         escaped++;
 365                 if (strncmp(line, "----", 4) == 0 ||
 366                     strstr(line, ": ") != NULL) {
 367                         if (strstr(line, SSH_COM_PRIVATE_BEGIN) != NULL)
 368                                 private = 1;
 369                         if (strstr(line, " END ") != NULL) {
 370                                 break;
 371                         }
 372                         /* fprintf(stderr, "ignore: %s", line); */
 373                         continue;
 374                 }
 375                 if (escaped) {
 376                         escaped--;
 377                         /* fprintf(stderr, "escaped: %s", line); */
 378                         continue;
 379                 }
 380                 strlcat(encoded, line, sizeof(encoded));
 381         }
 382         len = strlen(encoded);
 383         if (((len % 4) == 3) &&
 384             (encoded[len-1] == '=') &&
 385             (encoded[len-2] == '=') &&
 386             (encoded[len-3] == '='))
 387                 encoded[len-3] = '\0';
 388         blen = uudecode(encoded, blob, sizeof(blob));
 389         if (blen < 0) {
 390                 fprintf(stderr, "uudecode failed.\n");
 391                 exit(1);
 392         }
 393         k = private ?
 394             do_convert_private_ssh2_from_blob(blob, blen) :
 395             key_from_blob(blob, blen);
 396         if (k == NULL) {
 397                 fprintf(stderr, "decode blob failed.\n");
 398                 exit(1);
 399         }
 400         ok = private ?
 401             (k->type == KEY_DSA ?
 402                  PEM_write_DSAPrivateKey(stdout, k->dsa, NULL, NULL, 0, NULL, NULL) :
 403                  PEM_write_RSAPrivateKey(stdout, k->rsa, NULL, NULL, 0, NULL, NULL)) :
 404             key_write(k, stdout);
 405         if (!ok) {
 406                 fprintf(stderr, "key write failed");
 407                 exit(1);
 408         }
 409         key_free(k);
 410         if (!private)
 411                 fprintf(stdout, "\n");
 412         fclose(fp);
 413         exit(0);
 414 }
 415
 416 static void
 417 do_print_public(struct passwd *pw)
 418 {
 419         Key *prv;
 420         struct stat st;
 421
 422         if (!have_identity)
 423                 ask_filename(pw, "Enter file in which the key is");
 424         if (stat(identity_file, &st) < 0) {
 425                 perror(identity_file);
 426                 exit(1);
 427         }
 428         prv = load_identity(identity_file);
 429         if (prv == NULL) {
 430                 fprintf(stderr, "load failed\n");
 431                 exit(1);
 432         }
 433         if (!key_write(prv, stdout))
 434                 fprintf(stderr, "key_write failed");
 435         key_free(prv);
 436         fprintf(stdout, "\n");
 437         exit(0);
 438 }
 439
 440 #ifdef SMARTCARD
 441 static void
 442 do_upload(struct passwd *pw, const char *sc_reader_id)
 443 {
 444         Key *prv = NULL;
 445         struct stat st;
 446         int ret;
 447
 448         if (!have_identity)
 449                 ask_filename(pw, "Enter file in which the key is");
 450         if (stat(identity_file, &st) < 0) {
 451                 perror(identity_file);
 452                 exit(1);
 453         }
 454         prv = load_identity(identity_file);
 455         if (prv == NULL) {
 456                 error("load failed");
 457                 exit(1);
 458         }
 459         ret = sc_put_key(prv, sc_reader_id);
 460         key_free(prv);
 461         if (ret < 0)
 462                 exit(1);
 463         logit("loading key done");
 464         exit(0);
 465 }
 466
 467 static void
 468 do_download(struct passwd *pw, const char *sc_reader_id)
 469 {
 470         Key **keys = NULL;
 471         int i;
 472
 473         keys = sc_get_keys(sc_reader_id, NULL);
 474         if (keys == NULL)
 475                 fatal("cannot read public key from smartcard");
 476         for (i = 0; keys[i]; i++) {
 477                 key_write(keys[i], stdout);
 478                 key_free(keys[i]);
 479                 fprintf(stdout, "\n");
 480         }
 481         xfree(keys);
 482         exit(0);
 483 }
 484 #endif /* SMARTCARD */
 485
 486 static void
 487 do_fingerprint(struct passwd *pw)
 488 {
 489         FILE *f;
 490         Key *public;
 491         char *comment = NULL, *cp, *ep, line[16*1024], *fp;
 492         int i, skip = 0, num = 1, invalid = 1;
 493         enum fp_rep rep;
 494         enum fp_type fptype;
 495         struct stat st;
 496
 497         fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
 498         rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;
 499
 500         if (!have_identity)
 501                 ask_filename(pw, "Enter file in which the key is");
 502         if (stat(identity_file, &st) < 0) {
 503                 perror(identity_file);
 504                 exit(1);
 505         }
 506         public = key_load_public(identity_file, &comment);
 507         if (public != NULL) {
 508                 fp = key_fingerprint(public, fptype, rep);
 509                 printf("%u %s %s\n", key_size(public), fp, comment);
 510                 key_free(public);
 511                 xfree(comment);
 512                 xfree(fp);
 513                 exit(0);
 514         }
 515         if (comment)
 516                 xfree(comment);
 517
 518         f = fopen(identity_file, "r");
 519         if (f != NULL) {
 520                 while (fgets(line, sizeof(line), f)) {
 521                         i = strlen(line) - 1;
 522                         if (line[i] != '\n') {
 523                                 error("line %d too long: %.40s...", num, line);
 524                                 skip = 1;
 525                                 continue;
 526                         }
 527                         num++;
 528                         if (skip) {
 529                                 skip = 0;
 530                                 continue;
 531                         }
 532                         line[i] = '\0';
 533
 534                         /* Skip leading whitespace, empty and comment lines. */
 535                         for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 536                                 ;
 537                         if (!*cp || *cp == '\n' || *cp == '#')
 538                                 continue ;
 539                         i = strtol(cp, &ep, 10);
 540                         if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
 541                                 int quoted = 0;
 542                                 comment = cp;
 543                                 for (; *cp && (quoted || (*cp != ' ' &&
 544                                     *cp != '\t')); cp++) {
 545                                         if (*cp == '\\' && cp[1] == '"')
 546                                                 cp++;   /* Skip both */
 547                                         else if (*cp == '"')
 548                                                 quoted = !quoted;
 549                                 }
 550                                 if (!*cp)
 551                                         continue;
 552                                 *cp++ = '\0';
 553                         }
 554                         ep = cp;
 555                         public = key_new(KEY_RSA1);
 556                         if (key_read(public, &cp) != 1) {
 557                                 cp = ep;
 558                                 key_free(public);
 559                                 public = key_new(KEY_UNSPEC);
 560                                 if (key_read(public, &cp) != 1) {
 561                                         key_free(public);
 562                                         continue;
 563                                 }
 564                         }
 565                         comment = *cp ? cp : comment;
 566                         fp = key_fingerprint(public, fptype, rep);
 567                         printf("%u %s %s\n", key_size(public), fp,
 568                             comment ? comment : "no comment");
 569                         xfree(fp);
 570                         key_free(public);
 571                         invalid = 0;
 572                 }
 573                 fclose(f);
 574         }
 575         if (invalid) {
 576                 printf("%s is not a public key file.\n", identity_file);
 577                 exit(1);
 578         }
 579         exit(0);
 580 }
 581
 582 static void
 583 print_host(FILE *f, char *name, Key *public, int hash)
 584 {
 585         if (hash && (name = host_hash(name, NULL, 0)) == NULL)
 586                 fatal("hash_host failed");
 587         fprintf(f, "%s ", name);
 588         if (!key_write(public, f))
 589                 fatal("key_write failed");
 590         fprintf(f, "\n");
 591 }
 592
 593 static void
 594 do_known_hosts(struct passwd *pw, const char *name)
 595 {
 596         FILE *in, *out = stdout;
 597         Key *public;
 598         char *cp, *cp2, *kp, *kp2;
 599         char line[16*1024], tmp[MAXPATHLEN], old[MAXPATHLEN];
 600         int c, i, skip = 0, inplace = 0, num = 0, invalid = 0, has_unhashed = 0;
 601
 602         if (!have_identity) {
 603                 cp = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
 604                 if (strlcpy(identity_file, cp, sizeof(identity_file)) >=
 605                     sizeof(identity_file))
 606                         fatal("Specified known hosts path too long");
 607                 xfree(cp);
 608                 have_identity = 1;
 609         }
 610         if ((in = fopen(identity_file, "r")) == NULL)
 611                 fatal("fopen: %s", strerror(errno));
 612
 613         /*
 614          * Find hosts goes to stdout, hash and deletions happen in-place
 615          * A corner case is ssh-keygen -HF foo, which should go to stdout
 616          */
 617         if (!find_host && (hash_hosts || delete_host)) {
 618                 if (strlcpy(tmp, identity_file, sizeof(tmp)) >= sizeof(tmp) ||
 619                     strlcat(tmp, ".XXXXXXXXXX", sizeof(tmp)) >= sizeof(tmp) ||
 620                     strlcpy(old, identity_file, sizeof(old)) >= sizeof(old) ||
 621                     strlcat(old, ".old", sizeof(old)) >= sizeof(old))
 622                         fatal("known_hosts path too long");
 623                 umask(077);
 624                 if ((c = mkstemp(tmp)) == -1)
 625                         fatal("mkstemp: %s", strerror(errno));
 626                 if ((out = fdopen(c, "w")) == NULL) {
 627                         c = errno;
 628                         unlink(tmp);
 629                         fatal("fdopen: %s", strerror(c));
 630                 }
 631                 inplace = 1;
 632         }
 633
 634         while (fgets(line, sizeof(line), in)) {
 635                 num++;
 636                 i = strlen(line) - 1;
 637                 if (line[i] != '\n') {
 638                         error("line %d too long: %.40s...", num, line);
 639                         skip = 1;
 640                         invalid = 1;
 641                         continue;
 642                 }
 643                 if (skip) {
 644                         skip = 0;
 645                         continue;
 646                 }
 647                 line[i] = '\0';
 648
 649                 /* Skip leading whitespace, empty and comment lines. */
 650                 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
 651                         ;
 652                 if (!*cp || *cp == '\n' || *cp == '#') {
 653                         if (inplace)
 654                                 fprintf(out, "%s\n", cp);
 655                         continue;
 656                 }
 657                 /* Find the end of the host name portion. */
 658                 for (kp = cp; *kp && *kp != ' ' && *kp != '\t'; kp++)
 659                         ;
 660                 if (*kp == '\0' || *(kp + 1) == '\0') {
 661                         error("line %d missing key: %.40s...",
 662                             num, line);
 663                         invalid = 1;
 664                         continue;
 665                 }
 666                 *kp++ = '\0';
 667                 kp2 = kp;
 668
 669                 public = key_new(KEY_RSA1);
 670                 if (key_read(public, &kp) != 1) {
 671                         kp = kp2;
 672                         key_free(public);
 673                         public = key_new(KEY_UNSPEC);
 674                         if (key_read(public, &kp) != 1) {
 675                                 error("line %d invalid key: %.40s...",
 676                                     num, line);
 677                                 key_free(public);
 678                                 invalid = 1;
 679                                 continue;
 680                         }
 681                 }
 682
 683                 if (*cp == HASH_DELIM) {
 684                         if (find_host || delete_host) {
 685                                 cp2 = host_hash(name, cp, strlen(cp));
 686                                 if (cp2 == NULL) {
 687                                         error("line %d: invalid hashed "
 688                                             "name: %.64s...", num, line);
 689                                         invalid = 1;
 690                                         continue;
 691                                 }
 692                                 c = (strcmp(cp2, cp) == 0);
 693                                 if (find_host && c) {
 694                                         printf("# Host %s found: "
 695                                             "line %d type %s\n", name,
 696                                             num, key_type(public));
 697                                         print_host(out, cp, public, 0);
 698                                 }
 699                                 if (delete_host && !c)
 700                                         print_host(out, cp, public, 0);
 701                         } else if (hash_hosts)
 702                                 print_host(out, cp, public, 0);
 703                 } else {
 704                         if (find_host || delete_host) {
 705                                 c = (match_hostname(name, cp,
 706                                     strlen(cp)) == 1);
 707                                 if (find_host && c) {
 708                                         printf("# Host %s found: "
 709                                             "line %d type %s\n", name,
 710                                             num, key_type(public));
 711                                         print_host(out, cp, public, hash_hosts);
 712                                 }
 713                                 if (delete_host && !c)
 714                                         print_host(out, cp, public, 0);
 715                         } else if (hash_hosts) {
 716                                 for (cp2 = strsep(&cp, ",");
 717                                     cp2 != NULL && *cp2 != '\0';
 718                                     cp2 = strsep(&cp, ",")) {
 719                                         if (strcspn(cp2, "*?!") != strlen(cp2))
 720                                                 fprintf(stderr, "Warning: "
 721                                                     "ignoring host name with "
 722                                                     "metacharacters: %.64s\n",
 723                                                     cp2);
 724                                         else
 725                                                 print_host(out, cp2, public, 1);
 726                                 }
 727                                 has_unhashed = 1;
 728                         }
 729                 }
 730                 key_free(public);
 731         }
 732         fclose(in);
 733
 734         if (invalid) {
 735                 fprintf(stderr, "%s is not a valid known_host file.\n",
 736                     identity_file);
 737                 if (inplace) {
 738                         fprintf(stderr, "Not replacing existing known_hosts "
 739                             "file because of errors\n");
 740                         fclose(out);
 741                         unlink(tmp);
 742                 }
 743                 exit(1);
 744         }
 745
 746         if (inplace) {
 747                 fclose(out);
 748
 749                 /* Backup existing file */
 750                 if (unlink(old) == -1 && errno != ENOENT)
 751                         fatal("unlink %.100s: %s", old, strerror(errno));
 752                 if (link(identity_file, old) == -1)
 753                         fatal("link %.100s to %.100s: %s", identity_file, old,
 754                             strerror(errno));
 755                 /* Move new one into place */
 756                 if (rename(tmp, identity_file) == -1) {
 757                         error("rename\"%s\" to \"%s\": %s", tmp, identity_file,
 758                             strerror(errno));
 759                         unlink(tmp);
 760                         unlink(old);
 761                         exit(1);
 762                 }
 763
 764                 fprintf(stderr, "%s updated.\n", identity_file);
 765                 fprintf(stderr, "Original contents retained as %s\n", old);
 766                 if (has_unhashed) {
 767                         fprintf(stderr, "WARNING: %s contains unhashed "
 768                             "entries\n", old);
 769                         fprintf(stderr, "Delete this file to ensure privacy "
 770                             "of hostnames\n");
 771                 }
 772         }
 773
 774         exit(0);
 775 }
 776
 777 /*
 778  * Perform changing a passphrase.  The argument is the passwd structure
 779  * for the current user.
 780  */
 781 static void
 782 do_change_passphrase(struct passwd *pw)
 783 {
 784         char *comment;
 785         char *old_passphrase, *passphrase1, *passphrase2;
 786         struct stat st;
 787         Key *private;
 788
 789         if (!have_identity)
 790                 ask_filename(pw, "Enter file in which the key is");
 791         if (stat(identity_file, &st) < 0) {
 792                 perror(identity_file);
 793                 exit(1);
 794         }
 795         /* Try to load the file with empty passphrase. */
 796         private = key_load_private(identity_file, "", &comment);
 797         if (private == NULL) {
 798                 if (identity_passphrase)
 799                         old_passphrase = xstrdup(identity_passphrase);
 800                 else
 801                         old_passphrase =
 802                             read_passphrase("Enter old passphrase: ",
 803                             RP_ALLOW_STDIN);
 804                 private = key_load_private(identity_file, old_passphrase,
 805                     &comment);
 806                 memset(old_passphrase, 0, strlen(old_passphrase));
 807                 xfree(old_passphrase);
 808                 if (private == NULL) {
 809                         printf("Bad passphrase.\n");
 810                         exit(1);
 811                 }
 812         }
 813         printf("Key has comment '%s'\n", comment);
 814
 815         /* Ask the new passphrase (twice). */
 816         if (identity_new_passphrase) {
 817                 passphrase1 = xstrdup(identity_new_passphrase);
 818                 passphrase2 = NULL;
 819         } else {
 820                 passphrase1 =
 821                         read_passphrase("Enter new passphrase (empty for no "
 822                             "passphrase): ", RP_ALLOW_STDIN);
 823                 passphrase2 = read_passphrase("Enter same passphrase again: ",
 824                     RP_ALLOW_STDIN);
 825
 826                 /* Verify that they are the same. */
 827                 if (strcmp(passphrase1, passphrase2) != 0) {
 828                         memset(passphrase1, 0, strlen(passphrase1));
 829                         memset(passphrase2, 0, strlen(passphrase2));
 830                         xfree(passphrase1);
 831                         xfree(passphrase2);
 832                         printf("Pass phrases do not match.  Try again.\n");
 833                         exit(1);
 834                 }
 835                 /* Destroy the other copy. */
 836                 memset(passphrase2, 0, strlen(passphrase2));
 837                 xfree(passphrase2);
 838         }
 839
 840         /* Save the file using the new passphrase. */
 841         if (!key_save_private(private, identity_file, passphrase1, comment)) {
 842                 printf("Saving the key failed: %s.\n", identity_file);
 843                 memset(passphrase1, 0, strlen(passphrase1));
 844                 xfree(passphrase1);
 845                 key_free(private);
 846                 xfree(comment);
 847                 exit(1);
 848         }
 849         /* Destroy the passphrase and the copy of the key in memory. */
 850         memset(passphrase1, 0, strlen(passphrase1));
 851         xfree(passphrase1);
 852         key_free(private);               /* Destroys contents */
 853         xfree(comment);
 854
 855         printf("Your identification has been saved with the new passphrase.\n");
 856         exit(0);
 857 }
 858
 859 /*
 860  * Print the SSHFP RR.
 861  */
 862 static int
 863 do_print_resource_record(struct passwd *pw, char *fname, char *hname)
 864 {
 865         Key *public;
 866         char *comment = NULL;
 867         struct stat st;
 868
 869         if (fname == NULL)
 870                 ask_filename(pw, "Enter file in which the key is");
 871         if (stat(fname, &st) < 0) {
 872                 if (errno == ENOENT)
 873                         return 0;
 874                 perror(fname);
 875                 exit(1);
 876         }
 877         public = key_load_public(fname, &comment);
 878         if (public != NULL) {
 879                 export_dns_rr(hname, public, stdout, print_generic);
 880                 key_free(public);
 881                 xfree(comment);
 882                 return 1;
 883         }
 884         if (comment)
 885                 xfree(comment);
 886
 887         printf("failed to read v2 public key from %s.\n", fname);
 888         exit(1);
 889 }
 890
 891 /*
 892  * Change the comment of a private key file.
 893  */
 894 static void
 895 do_change_comment(struct passwd *pw)
 896 {
 897         char new_comment[1024], *comment, *passphrase;
 898         Key *private;
 899         Key *public;
 900         struct stat st;
 901         FILE *f;
 902         int fd;
 903
 904         if (!have_identity)
 905                 ask_filename(pw, "Enter file in which the key is");
 906         if (stat(identity_file, &st) < 0) {
 907                 perror(identity_file);
 908                 exit(1);
 909         }
 910         private = key_load_private(identity_file, "", &comment);
 911         if (private == NULL) {
 912                 if (identity_passphrase)
 913                         passphrase = xstrdup(identity_passphrase);
 914                 else if (identity_new_passphrase)
 915                         passphrase = xstrdup(identity_new_passphrase);
 916                 else
 917                         passphrase = read_passphrase("Enter passphrase: ",
 918                             RP_ALLOW_STDIN);
 919                 /* Try to load using the passphrase. */
 920                 private = key_load_private(identity_file, passphrase, &comment);
 921                 if (private == NULL) {
 922                         memset(passphrase, 0, strlen(passphrase));
 923                         xfree(passphrase);
 924                         printf("Bad passphrase.\n");
 925                         exit(1);
 926                 }
 927         } else {
 928                 passphrase = xstrdup("");
 929         }
 930         if (private->type != KEY_RSA1) {
 931                 fprintf(stderr, "Comments are only supported for RSA1 keys.\n");
 932                 key_free(private);
 933                 exit(1);
 934         }
 935         printf("Key now has comment '%s'\n", comment);
 936
 937         if (identity_comment) {
 938                 strlcpy(new_comment, identity_comment, sizeof(new_comment));
 939         } else {
 940                 printf("Enter new comment: ");
 941                 fflush(stdout);
 942                 if (!fgets(new_comment, sizeof(new_comment), stdin)) {
 943                         memset(passphrase, 0, strlen(passphrase));
 944                         key_free(private);
 945                         exit(1);
 946                 }
 947                 if (strchr(new_comment, '\n'))
 948                         *strchr(new_comment, '\n') = 0;
 949         }
 950
 951         /* Save the file using the new passphrase. */
 952         if (!key_save_private(private, identity_file, passphrase, new_comment)) {
 953                 printf("Saving the key failed: %s.\n", identity_file);
 954                 memset(passphrase, 0, strlen(passphrase));
 955                 xfree(passphrase);
 956                 key_free(private);
 957                 xfree(comment);
 958                 exit(1);
 959         }
 960         memset(passphrase, 0, strlen(passphrase));
 961         xfree(passphrase);
 962         public = key_from_private(private);
 963         key_free(private);
 964
 965         strlcat(identity_file, ".pub", sizeof(identity_file));
 966         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 967         if (fd == -1) {
 968                 printf("Could not save your public key in %s\n", identity_file);
 969                 exit(1);
 970         }
 971         f = fdopen(fd, "w");
 972         if (f == NULL) {
 973                 printf("fdopen %s failed", identity_file);
 974                 exit(1);
 975         }
 976         if (!key_write(public, f))
 977                 fprintf(stderr, "write key failed");
 978         key_free(public);
 979         fprintf(f, " %s\n", new_comment);
 980         fclose(f);
 981
 982         xfree(comment);
 983
 984         printf("The comment in your key file has been changed.\n");
 985         exit(0);
 986 }
 987
 988 static void
 989 usage(void)
 990 {
 991         fprintf(stderr, "Usage: %s [options]\n", __progname);
 992         fprintf(stderr, "Options:\n");
 993         fprintf(stderr, "  -a trials   Number of trials for screening DH-GEX moduli.\n");
 994         fprintf(stderr, "  -B          Show bubblebabble digest of key file.\n");
 995         fprintf(stderr, "  -b bits     Number of bits in the key to create.\n");
 996         fprintf(stderr, "  -C comment  Provide new comment.\n");
 997         fprintf(stderr, "  -c          Change comment in private and public key files.\n");
 998 #ifdef SMARTCARD
 999         fprintf(stderr, "  -D reader   Download public key from smartcard.\n");
1000 #endif /* SMARTCARD */
1001         fprintf(stderr, "  -e          Convert OpenSSH to IETF SECSH key file.\n");
1002         fprintf(stderr, "  -F hostname Find hostname in known hosts file.\n");
1003         fprintf(stderr, "  -f filename Filename of the key file.\n");
1004         fprintf(stderr, "  -G file     Generate candidates for DH-GEX moduli.\n");
1005         fprintf(stderr, "  -g          Use generic DNS resource record format.\n");
1006         fprintf(stderr, "  -H          Hash names in known_hosts file.\n");
1007         fprintf(stderr, "  -i          Convert IETF SECSH to OpenSSH key file.\n");
1008         fprintf(stderr, "  -l          Show fingerprint of key file.\n");
1009         fprintf(stderr, "  -M memory   Amount of memory (MB) to use for generating DH-GEX moduli.\n");
1010         fprintf(stderr, "  -N phrase   Provide new passphrase.\n");
1011         fprintf(stderr, "  -P phrase   Provide old passphrase.\n");
1012         fprintf(stderr, "  -p          Change passphrase of private key file.\n");
1013         fprintf(stderr, "  -q          Quiet.\n");
1014         fprintf(stderr, "  -R hostname Remove host from known_hosts file.\n");
1015         fprintf(stderr, "  -r hostname Print DNS resource record.\n");
1016         fprintf(stderr, "  -S start    Start point (hex) for generating DH-GEX moduli.\n");
1017         fprintf(stderr, "  -T file     Screen candidates for DH-GEX moduli.\n");
1018         fprintf(stderr, "  -t type     Specify type of key to create.\n");
1019 #ifdef SMARTCARD
1020         fprintf(stderr, "  -U reader   Upload private key to smartcard.\n");
1021 #endif /* SMARTCARD */
1022         fprintf(stderr, "  -v          Verbose.\n");
1023         fprintf(stderr, "  -W gen      Generator to use for generating DH-GEX moduli.\n");
1024         fprintf(stderr, "  -y          Read private key file and print public key.\n");
1025
1026         exit(1);
1027 }
1028
1029 /*
1030  * Main program for key management.
1031  */
1032 int
1033 main(int ac, char **av)
1034 {
1035         char dotsshdir[MAXPATHLEN], comment[1024], *passphrase1, *passphrase2;
1036         char out_file[MAXPATHLEN], *reader_id = NULL;
1037         char *rr_hostname = NULL;
1038         Key *private, *public;
1039         struct passwd *pw;
1040         struct stat st;
1041         int opt, type, fd, download = 0;
1042         u_int32_t memory = 0, generator_wanted = 0, trials = 100;
1043         int do_gen_candidates = 0, do_screen_candidates = 0;
1044         int log_level = SYSLOG_LEVEL_INFO;
1045         BIGNUM *start = NULL;
1046         FILE *f;
1047         const char *errstr;
1048
1049         extern int optind;
1050         extern char *optarg;
1051
1052         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1053         sanitise_stdfd();
1054
1055         __progname = ssh_get_progname(av[0]);
1056
1057         SSLeay_add_all_algorithms();
1058         log_init(av[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
1059
1060         init_rng();
1061         seed_rng();
1062
1063         /* we need this for the home * directory.  */
1064         pw = getpwuid(getuid());
1065         if (!pw) {
1066                 printf("You don't exist, go away!\n");
1067                 exit(1);
1068         }
1069         if (gethostname(hostname, sizeof(hostname)) < 0) {
1070                 perror("gethostname");
1071                 exit(1);
1072         }
1073
1074         while ((opt = getopt(ac, av,
1075             "degiqpclBHvxXyF:b:f:t:U:D:P:N:C:r:g:R:T:G:M:S:a:W:")) != -1) {
1076                 switch (opt) {
1077                 case 'b':
1078                         bits = (u_int32_t)strtonum(optarg, 768, 32768, &errstr);
1079                         if (errstr)
1080                                 fatal("Bits has bad value %s (%s)",
1081                                         optarg, errstr);
1082                         break;
1083                 case 'F':
1084                         find_host = 1;
1085                         rr_hostname = optarg;
1086                         break;
1087                 case 'H':
1088                         hash_hosts = 1;
1089                         break;
1090                 case 'R':
1091                         delete_host = 1;
1092                         rr_hostname = optarg;
1093                         break;
1094                 case 'l':
1095                         print_fingerprint = 1;
1096                         break;
1097                 case 'B':
1098                         print_bubblebabble = 1;
1099                         break;
1100                 case 'p':
1101                         change_passphrase = 1;
1102                         break;
1103                 case 'c':
1104                         change_comment = 1;
1105                         break;
1106                 case 'f':
1107                         if (strlcpy(identity_file, optarg, sizeof(identity_file)) >=
1108                             sizeof(identity_file))
1109                                 fatal("Identity filename too long");
1110                         have_identity = 1;
1111                         break;
1112                 case 'g':
1113                         print_generic = 1;
1114                         break;
1115                 case 'P':
1116                         identity_passphrase = optarg;
1117                         break;
1118                 case 'N':
1119                         identity_new_passphrase = optarg;
1120                         break;
1121                 case 'C':
1122                         identity_comment = optarg;
1123                         break;
1124                 case 'q':
1125                         quiet = 1;
1126                         break;
1127                 case 'e':
1128                 case 'x':
1129                         /* export key */
1130                         convert_to_ssh2 = 1;
1131                         break;
1132                 case 'i':
1133                 case 'X':
1134                         /* import key */
1135                         convert_from_ssh2 = 1;
1136                         break;
1137                 case 'y':
1138                         print_public = 1;
1139                         break;
1140                 case 'd':
1141                         key_type_name = "dsa";
1142                         break;
1143                 case 't':
1144                         key_type_name = optarg;
1145                         break;
1146                 case 'D':
1147                         download = 1;
1148                         /*FALLTHROUGH*/
1149                 case 'U':
1150                         reader_id = optarg;
1151                         break;
1152                 case 'v':
1153                         if (log_level == SYSLOG_LEVEL_INFO)
1154                                 log_level = SYSLOG_LEVEL_DEBUG1;
1155                         else {
1156                                 if (log_level >= SYSLOG_LEVEL_DEBUG1 &&
1157                                     log_level < SYSLOG_LEVEL_DEBUG3)
1158                                         log_level++;
1159                         }
1160                         break;
1161                 case 'r':
1162                         rr_hostname = optarg;
1163                         break;
1164                 case 'W':
1165                         generator_wanted = (u_int32_t)strtonum(optarg, 1,
1166                             UINT_MAX, &errstr);
1167                         if (errstr)
1168                                 fatal("Desired generator has bad value: %s (%s)",
1169                                         optarg, errstr);
1170                         break;
1171                 case 'a':
1172                         trials = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1173                         if (errstr)
1174                                 fatal("Invalid number of trials: %s (%s)",
1175                                         optarg, errstr);
1176                         break;
1177                 case 'M':
1178                         memory = (u_int32_t)strtonum(optarg, 1, UINT_MAX, &errstr);
1179                         if (errstr) {
1180                                 fatal("Memory limit is %s: %s", errstr, optarg);
1181                         }
1182                         break;
1183                 case 'G':
1184                         do_gen_candidates = 1;
1185                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1186                             sizeof(out_file))
1187                                 fatal("Output filename too long");
1188                         break;
1189                 case 'T':
1190                         do_screen_candidates = 1;
1191                         if (strlcpy(out_file, optarg, sizeof(out_file)) >=
1192                             sizeof(out_file))
1193                                 fatal("Output filename too long");
1194                         break;
1195                 case 'S':
1196                         /* XXX - also compare length against bits */
1197                         if (BN_hex2bn(&start, optarg) == 0)
1198                                 fatal("Invalid start point.");
1199                         break;
1200                 case '?':
1201                 default:
1202                         usage();
1203                 }
1204         }
1205
1206         /* reinit */
1207         log_init(av[0], log_level, SYSLOG_FACILITY_USER, 1);
1208
1209         if (optind < ac) {
1210                 printf("Too many arguments.\n");
1211                 usage();
1212         }
1213         if (change_passphrase && change_comment) {
1214                 printf("Can only have one of -p and -c.\n");
1215                 usage();
1216         }
1217         if (delete_host || hash_hosts || find_host)
1218                 do_known_hosts(pw, rr_hostname);
1219         if (print_fingerprint || print_bubblebabble)
1220                 do_fingerprint(pw);
1221         if (change_passphrase)
1222                 do_change_passphrase(pw);
1223         if (change_comment)
1224                 do_change_comment(pw);
1225         if (convert_to_ssh2)
1226                 do_convert_to_ssh2(pw);
1227         if (convert_from_ssh2)
1228                 do_convert_from_ssh2(pw);
1229         if (print_public)
1230                 do_print_public(pw);
1231         if (rr_hostname != NULL) {
1232                 unsigned int n = 0;
1233
1234                 if (have_identity) {
1235                         n = do_print_resource_record(pw,
1236                             identity_file, rr_hostname);
1237                         if (n == 0) {
1238                                 perror(identity_file);
1239                                 exit(1);
1240                         }
1241                         exit(0);
1242                 } else {
1243
1244                         n += do_print_resource_record(pw,
1245                             _PATH_HOST_RSA_KEY_FILE, rr_hostname);
1246                         n += do_print_resource_record(pw,
1247                             _PATH_HOST_DSA_KEY_FILE, rr_hostname);
1248
1249                         if (n == 0)
1250                                 fatal("no keys found.");
1251                         exit(0);
1252                 }
1253         }
1254         if (reader_id != NULL) {
1255 #ifdef SMARTCARD
1256                 if (download)
1257                         do_download(pw, reader_id);
1258                 else
1259                         do_upload(pw, reader_id);
1260 #else /* SMARTCARD */
1261                 fatal("no support for smartcards.");
1262 #endif /* SMARTCARD */
1263         }
1264
1265         if (do_gen_candidates) {
1266                 FILE *out = fopen(out_file, "w");
1267
1268                 if (out == NULL) {
1269                         error("Couldn't open modulus candidate file \"%s\": %s",
1270                             out_file, strerror(errno));
1271                         return (1);
1272                 }
1273                 if (bits == 0)
1274                         bits = DEFAULT_BITS;
1275                 if (gen_candidates(out, memory, bits, start) != 0)
1276                         fatal("modulus candidate generation failed");
1277
1278                 return (0);
1279         }
1280
1281         if (do_screen_candidates) {
1282                 FILE *in;
1283                 FILE *out = fopen(out_file, "w");
1284
1285                 if (have_identity && strcmp(identity_file, "-") != 0) {
1286                         if ((in = fopen(identity_file, "r")) == NULL) {
1287                                 fatal("Couldn't open modulus candidate "
1288                                     "file \"%s\": %s", identity_file,
1289                                     strerror(errno));
1290                         }
1291                 } else
1292                         in = stdin;
1293
1294                 if (out == NULL) {
1295                         fatal("Couldn't open moduli file \"%s\": %s",
1296                             out_file, strerror(errno));
1297                 }
1298                 if (prime_test(in, out, trials, generator_wanted) != 0)
1299                         fatal("modulus screening failed");
1300                 return (0);
1301         }
1302
1303         arc4random_stir();
1304
1305         if (key_type_name == NULL)
1306                 key_type_name = "rsa";
1307
1308         type = key_type_from_name(key_type_name);
1309         if (type == KEY_UNSPEC) {
1310                 fprintf(stderr, "unknown key type %s\n", key_type_name);
1311                 exit(1);
1312         }
1313         if (bits == 0)
1314                 bits = (type == KEY_DSA) ? DEFAULT_BITS_DSA : DEFAULT_BITS;
1315         if (type == KEY_DSA && bits != 1024)
1316                 fatal("DSA keys must be 1024 bits");
1317         if (!quiet)
1318                 printf("Generating public/private %s key pair.\n", key_type_name);
1319         private = key_generate(type, bits);
1320         if (private == NULL) {
1321                 fprintf(stderr, "key_generate failed");
1322                 exit(1);
1323         }
1324         public  = key_from_private(private);
1325
1326         if (!have_identity)
1327                 ask_filename(pw, "Enter file in which to save the key");
1328
1329         /* Create ~/.ssh directory if it doesn't already exist. */
1330         snprintf(dotsshdir, sizeof dotsshdir, "%s/%s", pw->pw_dir, _PATH_SSH_USER_DIR);
1331         if (strstr(identity_file, dotsshdir) != NULL &&
1332             stat(dotsshdir, &st) < 0) {
1333                 if (mkdir(dotsshdir, 0700) < 0)
1334                         error("Could not create directory '%s'.", dotsshdir);
1335                 else if (!quiet)
1336                         printf("Created directory '%s'.\n", dotsshdir);
1337         }
1338         /* If the file already exists, ask the user to confirm. */
1339         if (stat(identity_file, &st) >= 0) {
1340                 char yesno[3];
1341                 printf("%s already exists.\n", identity_file);
1342                 printf("Overwrite (y/n)? ");
1343                 fflush(stdout);
1344                 if (fgets(yesno, sizeof(yesno), stdin) == NULL)
1345                         exit(1);
1346                 if (yesno[0] != 'y' && yesno[0] != 'Y')
1347                         exit(1);
1348         }
1349         /* Ask for a passphrase (twice). */
1350         if (identity_passphrase)
1351                 passphrase1 = xstrdup(identity_passphrase);
1352         else if (identity_new_passphrase)
1353                 passphrase1 = xstrdup(identity_new_passphrase);
1354         else {
1355 passphrase_again:
1356                 passphrase1 =
1357                         read_passphrase("Enter passphrase (empty for no "
1358                             "passphrase): ", RP_ALLOW_STDIN);
1359                 passphrase2 = read_passphrase("Enter same passphrase again: ",
1360                     RP_ALLOW_STDIN);
1361                 if (strcmp(passphrase1, passphrase2) != 0) {
1362                         /*
1363                          * The passphrases do not match.  Clear them and
1364                          * retry.
1365                          */
1366                         memset(passphrase1, 0, strlen(passphrase1));
1367                         memset(passphrase2, 0, strlen(passphrase2));
1368                         xfree(passphrase1);
1369                         xfree(passphrase2);
1370                         printf("Passphrases do not match.  Try again.\n");
1371                         goto passphrase_again;
1372                 }
1373                 /* Clear the other copy of the passphrase. */
1374                 memset(passphrase2, 0, strlen(passphrase2));
1375                 xfree(passphrase2);
1376         }
1377
1378         if (identity_comment) {
1379                 strlcpy(comment, identity_comment, sizeof(comment));
1380         } else {
1381                 /* Create default commend field for the passphrase. */
1382                 snprintf(comment, sizeof comment, "%s@%s", pw->pw_name, hostname);
1383         }
1384
1385         /* Save the key with the given passphrase and comment. */
1386         if (!key_save_private(private, identity_file, passphrase1, comment)) {
1387                 printf("Saving the key failed: %s.\n", identity_file);
1388                 memset(passphrase1, 0, strlen(passphrase1));
1389                 xfree(passphrase1);
1390                 exit(1);
1391         }
1392         /* Clear the passphrase. */
1393         memset(passphrase1, 0, strlen(passphrase1));
1394         xfree(passphrase1);
1395
1396         /* Clear the private key and the random number generator. */
1397         key_free(private);
1398         arc4random_stir();
1399
1400         if (!quiet)
1401                 printf("Your identification has been saved in %s.\n", identity_file);
1402
1403         strlcat(identity_file, ".pub", sizeof(identity_file));
1404         fd = open(identity_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
1405         if (fd == -1) {
1406                 printf("Could not save your public key in %s\n", identity_file);
1407                 exit(1);
1408         }
1409         f = fdopen(fd, "w");
1410         if (f == NULL) {
1411                 printf("fdopen %s failed", identity_file);
1412                 exit(1);
1413         }
1414         if (!key_write(public, f))
1415                 fprintf(stderr, "write key failed");
1416         fprintf(f, " %s\n", comment);
1417         fclose(f);
1418
1419         if (!quiet) {
1420                 char *fp = key_fingerprint(public, SSH_FP_MD5, SSH_FP_HEX);
1421                 printf("Your public key has been saved in %s.\n",
1422                     identity_file);
1423                 printf("The key fingerprint is:\n");
1424                 printf("%s %s\n", fp, comment);
1425                 xfree(fp);
1426         }
1427
1428         key_free(public);
1429         exit(0);
1430 }