authfile.c

   1 /* $OpenBSD: authfile.c,v 1.77 2009/10/22 22:26:13 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * This file contains functions for reading and writing identity files, and
   7  * for reading the passphrase from the user.
   8  *
   9  * As far as I am concerned, the code I have written for this software
  10  * can be used freely for any purpose.  Any derived versions of this
  11  * software must be clearly marked as such, and if the derived work is
  12  * incompatible with the protocol description in the RFC file, it must be
  13  * called by a name other than "ssh" or "Secure Shell".
  14  *
  15  *
  16  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  17  *
  18  * Redistribution and use in source and binary forms, with or without
  19  * modification, are permitted provided that the following conditions
  20  * are met:
  21  * 1. Redistributions of source code must retain the above copyright
  22  *    notice, this list of conditions and the following disclaimer.
  23  * 2. Redistributions in binary form must reproduce the above copyright
  24  *    notice, this list of conditions and the following disclaimer in the
  25  *    documentation and/or other materials provided with the distribution.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  28  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  29  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  30  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  31  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  32  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  33  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  34  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  35  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  36  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 #include "includes.h"
  40
  41 #include <sys/types.h>
  42 #include <sys/stat.h>
  43 #include <sys/param.h>
  44 #include <sys/uio.h>
  45
  46 #include <openssl/err.h>
  47 #include <openssl/evp.h>
  48 #include <openssl/pem.h>
  49
  50 /* compatibility with old or broken OpenSSL versions */
  51 #include "openbsd-compat/openssl-compat.h"
  52
  53 #include <errno.h>
  54 #include <fcntl.h>
  55 #include <stdarg.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <unistd.h>
  60
  61 #include "xmalloc.h"
  62 #include "cipher.h"
  63 #include "buffer.h"
  64 #include "key.h"
  65 #include "ssh.h"
  66 #include "log.h"
  67 #include "authfile.h"
  68 #include "rsa.h"
  69 #include "misc.h"
  70 #include "atomicio.h"
  71
  72 /* Version identification string for SSH v1 identity files. */
  73 static const char authfile_id_string[] =
  74     "SSH PRIVATE KEY FILE FORMAT 1.1\n";
  75
  76 /*
  77  * Saves the authentication (private) key in a file, encrypting it with
  78  * passphrase.  The identification of the file (lowest 64 bits of n) will
  79  * precede the key to provide identification of the key without needing a
  80  * passphrase.
  81  */
  82
  83 static int
  84 key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
  85     const char *comment)
  86 {
  87         Buffer buffer, encrypted;
  88         u_char buf[100], *cp;
  89         int fd, i, cipher_num;
  90         CipherContext ciphercontext;
  91         Cipher *cipher;
  92         u_int32_t rnd;
  93
  94         /*
  95          * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
  96          * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
  97          */
  98         cipher_num = (strcmp(passphrase, "") == 0) ?
  99             SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
 100         if ((cipher = cipher_by_number(cipher_num)) == NULL)
 101                 fatal("save_private_key_rsa: bad cipher");
 102
 103         /* This buffer is used to built the secret part of the private key. */
 104         buffer_init(&buffer);
 105
 106         /* Put checkbytes for checking passphrase validity. */
 107         rnd = arc4random();
 108         buf[0] = rnd & 0xff;
 109         buf[1] = (rnd >> 8) & 0xff;
 110         buf[2] = buf[0];
 111         buf[3] = buf[1];
 112         buffer_append(&buffer, buf, 4);
 113
 114         /*
 115          * Store the private key (n and e will not be stored because they
 116          * will be stored in plain text, and storing them also in encrypted
 117          * format would just give known plaintext).
 118          */
 119         buffer_put_bignum(&buffer, key->rsa->d);
 120         buffer_put_bignum(&buffer, key->rsa->iqmp);
 121         buffer_put_bignum(&buffer, key->rsa->q);        /* reverse from SSL p */
 122         buffer_put_bignum(&buffer, key->rsa->p);        /* reverse from SSL q */
 123
 124         /* Pad the part to be encrypted until its size is a multiple of 8. */
 125         while (buffer_len(&buffer) % 8 != 0)
 126                 buffer_put_char(&buffer, 0);
 127
 128         /* This buffer will be used to contain the data in the file. */
 129         buffer_init(&encrypted);
 130
 131         /* First store keyfile id string. */
 132         for (i = 0; authfile_id_string[i]; i++)
 133                 buffer_put_char(&encrypted, authfile_id_string[i]);
 134         buffer_put_char(&encrypted, 0);
 135
 136         /* Store cipher type. */
 137         buffer_put_char(&encrypted, cipher_num);
 138         buffer_put_int(&encrypted, 0);  /* For future extension */
 139
 140         /* Store public key.  This will be in plain text. */
 141         buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
 142         buffer_put_bignum(&encrypted, key->rsa->n);
 143         buffer_put_bignum(&encrypted, key->rsa->e);
 144         buffer_put_cstring(&encrypted, comment);
 145
 146         /* Allocate space for the private part of the key in the buffer. */
 147         cp = buffer_append_space(&encrypted, buffer_len(&buffer));
 148
 149         cipher_set_key_string(&ciphercontext, cipher, passphrase,
 150             CIPHER_ENCRYPT);
 151         cipher_crypt(&ciphercontext, cp,
 152             buffer_ptr(&buffer), buffer_len(&buffer));
 153         cipher_cleanup(&ciphercontext);
 154         memset(&ciphercontext, 0, sizeof(ciphercontext));
 155
 156         /* Destroy temporary data. */
 157         memset(buf, 0, sizeof(buf));
 158         buffer_free(&buffer);
 159
 160         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
 161         if (fd < 0) {
 162                 error("open %s failed: %s.", filename, strerror(errno));
 163                 buffer_free(&encrypted);
 164                 return 0;
 165         }
 166         if (atomicio(vwrite, fd, buffer_ptr(&encrypted),
 167             buffer_len(&encrypted)) != buffer_len(&encrypted)) {
 168                 error("write to key file %s failed: %s", filename,
 169                     strerror(errno));
 170                 buffer_free(&encrypted);
 171                 close(fd);
 172                 unlink(filename);
 173                 return 0;
 174         }
 175         close(fd);
 176         buffer_free(&encrypted);
 177         return 1;
 178 }
 179
 180 /* save SSH v2 key in OpenSSL PEM format */
 181 static int
 182 key_save_private_pem(Key *key, const char *filename, const char *_passphrase,
 183     const char *comment)
 184 {
 185         FILE *fp;
 186         int fd;
 187         int success = 0;
 188         int len = strlen(_passphrase);
 189         u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
 190 #if (OPENSSL_VERSION_NUMBER < 0x00907000L)
 191         const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
 192 #else
 193         const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL;
 194 #endif
 195
 196         if (len > 0 && len <= 4) {
 197                 error("passphrase too short: have %d bytes, need > 4", len);
 198                 return 0;
 199         }
 200         fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600);
 201         if (fd < 0) {
 202                 error("open %s failed: %s.", filename, strerror(errno));
 203                 return 0;
 204         }
 205         fp = fdopen(fd, "w");
 206         if (fp == NULL) {
 207                 error("fdopen %s failed: %s.", filename, strerror(errno));
 208                 close(fd);
 209                 return 0;
 210         }
 211         switch (key->type) {
 212         case KEY_DSA:
 213                 success = PEM_write_DSAPrivateKey(fp, key->dsa,
 214                     cipher, passphrase, len, NULL, NULL);
 215                 break;
 216         case KEY_RSA:
 217                 success = PEM_write_RSAPrivateKey(fp, key->rsa,
 218                     cipher, passphrase, len, NULL, NULL);
 219                 break;
 220         }
 221         fclose(fp);
 222         return success;
 223 }
 224
 225 int
 226 key_save_private(Key *key, const char *filename, const char *passphrase,
 227     const char *comment)
 228 {
 229         switch (key->type) {
 230         case KEY_RSA1:
 231                 return key_save_private_rsa1(key, filename, passphrase,
 232                     comment);
 233         case KEY_DSA:
 234         case KEY_RSA:
 235                 return key_save_private_pem(key, filename, passphrase,
 236                     comment);
 237         default:
 238                 break;
 239         }
 240         error("key_save_private: cannot save key type %d", key->type);
 241         return 0;
 242 }
 243
 244 /*
 245  * Loads the public part of the ssh v1 key file.  Returns NULL if an error was
 246  * encountered (the file does not exist or is not readable), and the key
 247  * otherwise.
 248  */
 249
 250 static Key *
 251 key_load_public_rsa1(int fd, const char *filename, char **commentp)
 252 {
 253         Buffer buffer;
 254         Key *pub;
 255         struct stat st;
 256         char *cp;
 257         u_int i;
 258         size_t len;
 259
 260         if (fstat(fd, &st) < 0) {
 261                 error("fstat for key file %.200s failed: %.100s",
 262                     filename, strerror(errno));
 263                 return NULL;
 264         }
 265         if (st.st_size > 1*1024*1024) {
 266                 error("key file %.200s too large", filename);
 267                 return NULL;
 268         }
 269         len = (size_t)st.st_size;               /* truncated */
 270
 271         buffer_init(&buffer);
 272         cp = buffer_append_space(&buffer, len);
 273
 274         if (atomicio(read, fd, cp, len) != len) {
 275                 debug("Read from key file %.200s failed: %.100s", filename,
 276                     strerror(errno));
 277                 buffer_free(&buffer);
 278                 return NULL;
 279         }
 280
 281         /* Check that it is at least big enough to contain the ID string. */
 282         if (len < sizeof(authfile_id_string)) {
 283                 debug3("Not a RSA1 key file %.200s.", filename);
 284                 buffer_free(&buffer);
 285                 return NULL;
 286         }
 287         /*
 288          * Make sure it begins with the id string.  Consume the id string
 289          * from the buffer.
 290          */
 291         for (i = 0; i < sizeof(authfile_id_string); i++)
 292                 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
 293                         debug3("Not a RSA1 key file %.200s.", filename);
 294                         buffer_free(&buffer);
 295                         return NULL;
 296                 }
 297         /* Skip cipher type and reserved data. */
 298         (void) buffer_get_char(&buffer);        /* cipher type */
 299         (void) buffer_get_int(&buffer);         /* reserved */
 300
 301         /* Read the public key from the buffer. */
 302         (void) buffer_get_int(&buffer);
 303         pub = key_new(KEY_RSA1);
 304         buffer_get_bignum(&buffer, pub->rsa->n);
 305         buffer_get_bignum(&buffer, pub->rsa->e);
 306         if (commentp)
 307                 *commentp = buffer_get_string(&buffer, NULL);
 308         /* The encrypted private part is not parsed by this function. */
 309
 310         buffer_free(&buffer);
 311         return pub;
 312 }
 313
 314 /* load public key from private-key file, works only for SSH v1 */
 315 Key *
 316 key_load_public_type(int type, const char *filename, char **commentp)
 317 {
 318         Key *pub;
 319         int fd;
 320
 321         if (type == KEY_RSA1) {
 322                 fd = open(filename, O_RDONLY);
 323                 if (fd < 0)
 324                         return NULL;
 325                 pub = key_load_public_rsa1(fd, filename, commentp);
 326                 close(fd);
 327                 return pub;
 328         }
 329         return NULL;
 330 }
 331
 332 /*
 333  * Loads the private key from the file.  Returns 0 if an error is encountered
 334  * (file does not exist or is not readable, or passphrase is bad). This
 335  * initializes the private key.
 336  * Assumes we are called under uid of the owner of the file.
 337  */
 338
 339 static Key *
 340 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
 341     char **commentp)
 342 {
 343         u_int i;
 344         int check1, check2, cipher_type;
 345         size_t len;
 346         Buffer buffer, decrypted;
 347         u_char *cp;
 348         CipherContext ciphercontext;
 349         Cipher *cipher;
 350         Key *prv = NULL;
 351         struct stat st;
 352
 353         if (fstat(fd, &st) < 0) {
 354                 error("fstat for key file %.200s failed: %.100s",
 355                     filename, strerror(errno));
 356                 close(fd);
 357                 return NULL;
 358         }
 359         if (st.st_size > 1*1024*1024) {
 360                 error("key file %.200s too large", filename);
 361                 close(fd);
 362                 return (NULL);
 363         }
 364         len = (size_t)st.st_size;               /* truncated */
 365
 366         buffer_init(&buffer);
 367         cp = buffer_append_space(&buffer, len);
 368
 369         if (atomicio(read, fd, cp, len) != len) {
 370                 debug("Read from key file %.200s failed: %.100s", filename,
 371                     strerror(errno));
 372                 buffer_free(&buffer);
 373                 close(fd);
 374                 return NULL;
 375         }
 376
 377         /* Check that it is at least big enough to contain the ID string. */
 378         if (len < sizeof(authfile_id_string)) {
 379                 debug3("Not a RSA1 key file %.200s.", filename);
 380                 buffer_free(&buffer);
 381                 close(fd);
 382                 return NULL;
 383         }
 384         /*
 385          * Make sure it begins with the id string.  Consume the id string
 386          * from the buffer.
 387          */
 388         for (i = 0; i < sizeof(authfile_id_string); i++)
 389                 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
 390                         debug3("Not a RSA1 key file %.200s.", filename);
 391                         buffer_free(&buffer);
 392                         close(fd);
 393                         return NULL;
 394                 }
 395
 396         /* Read cipher type. */
 397         cipher_type = buffer_get_char(&buffer);
 398         (void) buffer_get_int(&buffer); /* Reserved data. */
 399
 400         /* Read the public key from the buffer. */
 401         (void) buffer_get_int(&buffer);
 402         prv = key_new_private(KEY_RSA1);
 403
 404         buffer_get_bignum(&buffer, prv->rsa->n);
 405         buffer_get_bignum(&buffer, prv->rsa->e);
 406         if (commentp)
 407                 *commentp = buffer_get_string(&buffer, NULL);
 408         else
 409                 xfree(buffer_get_string(&buffer, NULL));
 410
 411         /* Check that it is a supported cipher. */
 412         cipher = cipher_by_number(cipher_type);
 413         if (cipher == NULL) {
 414                 debug("Unsupported cipher %d used in key file %.200s.",
 415                     cipher_type, filename);
 416                 buffer_free(&buffer);
 417                 goto fail;
 418         }
 419         /* Initialize space for decrypted data. */
 420         buffer_init(&decrypted);
 421         cp = buffer_append_space(&decrypted, buffer_len(&buffer));
 422
 423         /* Rest of the buffer is encrypted.  Decrypt it using the passphrase. */
 424         cipher_set_key_string(&ciphercontext, cipher, passphrase,
 425             CIPHER_DECRYPT);
 426         cipher_crypt(&ciphercontext, cp,
 427             buffer_ptr(&buffer), buffer_len(&buffer));
 428         cipher_cleanup(&ciphercontext);
 429         memset(&ciphercontext, 0, sizeof(ciphercontext));
 430         buffer_free(&buffer);
 431
 432         check1 = buffer_get_char(&decrypted);
 433         check2 = buffer_get_char(&decrypted);
 434         if (check1 != buffer_get_char(&decrypted) ||
 435             check2 != buffer_get_char(&decrypted)) {
 436                 if (strcmp(passphrase, "") != 0)
 437                         debug("Bad passphrase supplied for key file %.200s.",
 438                             filename);
 439                 /* Bad passphrase. */
 440                 buffer_free(&decrypted);
 441                 goto fail;
 442         }
 443         /* Read the rest of the private key. */
 444         buffer_get_bignum(&decrypted, prv->rsa->d);
 445         buffer_get_bignum(&decrypted, prv->rsa->iqmp);          /* u */
 446         /* in SSL and SSH v1 p and q are exchanged */
 447         buffer_get_bignum(&decrypted, prv->rsa->q);             /* p */
 448         buffer_get_bignum(&decrypted, prv->rsa->p);             /* q */
 449
 450         /* calculate p-1 and q-1 */
 451         rsa_generate_additional_parameters(prv->rsa);
 452
 453         buffer_free(&decrypted);
 454
 455         /* enable blinding */
 456         if (RSA_blinding_on(prv->rsa, NULL) != 1) {
 457                 error("key_load_private_rsa1: RSA_blinding_on failed");
 458                 goto fail;
 459         }
 460         close(fd);
 461         return prv;
 462
 463 fail:
 464         if (commentp)
 465                 xfree(*commentp);
 466         close(fd);
 467         key_free(prv);
 468         return NULL;
 469 }
 470
 471 Key *
 472 key_load_private_pem(int fd, int type, const char *passphrase,
 473     char **commentp)
 474 {
 475         FILE *fp;
 476         EVP_PKEY *pk = NULL;
 477         Key *prv = NULL;
 478         char *name = "<no key>";
 479
 480         fp = fdopen(fd, "r");
 481         if (fp == NULL) {
 482                 error("fdopen failed: %s", strerror(errno));
 483                 close(fd);
 484                 return NULL;
 485         }
 486         pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
 487         if (pk == NULL) {
 488                 debug("PEM_read_PrivateKey failed");
 489                 (void)ERR_get_error();
 490         } else if (pk->type == EVP_PKEY_RSA &&
 491             (type == KEY_UNSPEC||type==KEY_RSA)) {
 492                 prv = key_new(KEY_UNSPEC);
 493                 prv->rsa = EVP_PKEY_get1_RSA(pk);
 494                 prv->type = KEY_RSA;
 495                 name = "rsa w/o comment";
 496 #ifdef DEBUG_PK
 497                 RSA_print_fp(stderr, prv->rsa, 8);
 498 #endif
 499                 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
 500                         error("key_load_private_pem: RSA_blinding_on failed");
 501                         key_free(prv);
 502                         prv = NULL;
 503                 }
 504         } else if (pk->type == EVP_PKEY_DSA &&
 505             (type == KEY_UNSPEC||type==KEY_DSA)) {
 506                 prv = key_new(KEY_UNSPEC);
 507                 prv->dsa = EVP_PKEY_get1_DSA(pk);
 508                 prv->type = KEY_DSA;
 509                 name = "dsa w/o comment";
 510 #ifdef DEBUG_PK
 511                 DSA_print_fp(stderr, prv->dsa, 8);
 512 #endif
 513         } else {
 514                 error("PEM_read_PrivateKey: mismatch or "
 515                     "unknown EVP_PKEY save_type %d", pk->save_type);
 516         }
 517         fclose(fp);
 518         if (pk != NULL)
 519                 EVP_PKEY_free(pk);
 520         if (prv != NULL && commentp)
 521                 *commentp = xstrdup(name);
 522         debug("read PEM private key done: type %s",
 523             prv ? key_type(prv) : "<unknown>");
 524         return prv;
 525 }
 526
 527 int
 528 key_perm_ok(int fd, const char *filename)
 529 {
 530         struct stat st;
 531
 532         if (fstat(fd, &st) < 0)
 533                 return 0;
 534         /*
 535          * if a key owned by the user is accessed, then we check the
 536          * permissions of the file. if the key owned by a different user,
 537          * then we don't care.
 538          */
 539 #ifdef HAVE_CYGWIN
 540         if (check_ntsec(filename))
 541 #endif
 542         if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
 543                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 544                 error("@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @");
 545                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 546                 error("Permissions 0%3.3o for '%s' are too open.",
 547                     (u_int)st.st_mode & 0777, filename);
 548                 error("It is recommended that your private key files are NOT accessible by others.");
 549                 error("This private key will be ignored.");
 550                 return 0;
 551         }
 552         return 1;
 553 }
 554
 555 Key *
 556 key_load_private_type(int type, const char *filename, const char *passphrase,
 557     char **commentp, int *perm_ok)
 558 {
 559         int fd;
 560
 561         fd = open(filename, O_RDONLY);
 562         if (fd < 0)
 563                 return NULL;
 564         if (!key_perm_ok(fd, filename)) {
 565                 if (perm_ok != NULL)
 566                         *perm_ok = 0;
 567                 error("bad permissions: ignore key: %s", filename);
 568                 close(fd);
 569                 return NULL;
 570         }
 571         if (perm_ok != NULL)
 572                 *perm_ok = 1;
 573         switch (type) {
 574         case KEY_RSA1:
 575                 return key_load_private_rsa1(fd, filename, passphrase,
 576                     commentp);
 577                 /* closes fd */
 578         case KEY_DSA:
 579         case KEY_RSA:
 580         case KEY_UNSPEC:
 581                 return key_load_private_pem(fd, type, passphrase, commentp);
 582                 /* closes fd */
 583         default:
 584                 close(fd);
 585                 break;
 586         }
 587         return NULL;
 588 }
 589
 590 Key *
 591 key_load_private(const char *filename, const char *passphrase,
 592     char **commentp)
 593 {
 594         Key *pub, *prv;
 595         int fd;
 596
 597         fd = open(filename, O_RDONLY);
 598         if (fd < 0)
 599                 return NULL;
 600         if (!key_perm_ok(fd, filename)) {
 601                 error("bad permissions: ignore key: %s", filename);
 602                 close(fd);
 603                 return NULL;
 604         }
 605         pub = key_load_public_rsa1(fd, filename, commentp);
 606         lseek(fd, (off_t) 0, SEEK_SET);         /* rewind */
 607         if (pub == NULL) {
 608                 /* closes fd */
 609                 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
 610                 /* use the filename as a comment for PEM */
 611                 if (commentp && prv)
 612                         *commentp = xstrdup(filename);
 613         } else {
 614                 /* it's a SSH v1 key if the public key part is readable */
 615                 key_free(pub);
 616                 /* closes fd */
 617                 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
 618         }
 619         return prv;
 620 }
 621
 622 static int
 623 key_try_load_public(Key *k, const char *filename, char **commentp)
 624 {
 625         FILE *f;
 626         char line[SSH_MAX_PUBKEY_BYTES];
 627         char *cp;
 628         u_long linenum = 0;
 629
 630         f = fopen(filename, "r");
 631         if (f != NULL) {
 632                 while (read_keyfile_line(f, filename, line, sizeof(line),
 633                             &linenum) != -1) {
 634                         cp = line;
 635                         switch (*cp) {
 636                         case '#':
 637                         case '\n':
 638                         case '\0':
 639                                 continue;
 640                         }
 641                         /* Skip leading whitespace. */
 642                         for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
 643                                 ;
 644                         if (*cp) {
 645                                 if (key_read(k, &cp) == 1) {
 646                                         if (commentp)
 647                                                 *commentp=xstrdup(filename);
 648                                         fclose(f);
 649                                         return 1;
 650                                 }
 651                         }
 652                 }
 653                 fclose(f);
 654         }
 655         return 0;
 656 }
 657
 658 /* load public key from ssh v1 private or any pubkey file */
 659 Key *
 660 key_load_public(const char *filename, char **commentp)
 661 {
 662         Key *pub;
 663         char file[MAXPATHLEN];
 664
 665         /* try rsa1 private key */
 666         pub = key_load_public_type(KEY_RSA1, filename, commentp);
 667         if (pub != NULL)
 668                 return pub;
 669
 670         /* try rsa1 public key */
 671         pub = key_new(KEY_RSA1);
 672         if (key_try_load_public(pub, filename, commentp) == 1)
 673                 return pub;
 674         key_free(pub);
 675
 676         /* try ssh2 public key */
 677         pub = key_new(KEY_UNSPEC);
 678         if (key_try_load_public(pub, filename, commentp) == 1)
 679                 return pub;
 680         if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
 681             (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
 682             (key_try_load_public(pub, file, commentp) == 1))
 683                 return pub;
 684         key_free(pub);
 685         return NULL;
 686 }