authfile.c

   1 /* $OpenBSD: authfile.c,v 1.87 2010/11/29 18:57:04 markus 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  * Serialises the authentication (private) key to a blob, encrypting it with
  78  * passphrase.  The identification of the blob (lowest 64 bits of n) will
  79  * precede the key to provide identification of the key without needing a
  80  * passphrase.
  81  */
  82 static int
  83 key_private_rsa1_to_blob(Key *key, Buffer *blob, const char *passphrase,
  84     const char *comment)
  85 {
  86         Buffer buffer, encrypted;
  87         u_char buf[100], *cp;
  88         int i, cipher_num;
  89         CipherContext ciphercontext;
  90         Cipher *cipher;
  91         u_int32_t rnd;
  92
  93         /*
  94          * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting
  95          * to another cipher; otherwise use SSH_AUTHFILE_CIPHER.
  96          */
  97         cipher_num = (strcmp(passphrase, "") == 0) ?
  98             SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER;
  99         if ((cipher = cipher_by_number(cipher_num)) == NULL)
 100                 fatal("save_private_key_rsa: bad cipher");
 101
 102         /* This buffer is used to built the secret part of the private key. */
 103         buffer_init(&buffer);
 104
 105         /* Put checkbytes for checking passphrase validity. */
 106         rnd = arc4random();
 107         buf[0] = rnd & 0xff;
 108         buf[1] = (rnd >> 8) & 0xff;
 109         buf[2] = buf[0];
 110         buf[3] = buf[1];
 111         buffer_append(&buffer, buf, 4);
 112
 113         /*
 114          * Store the private key (n and e will not be stored because they
 115          * will be stored in plain text, and storing them also in encrypted
 116          * format would just give known plaintext).
 117          */
 118         buffer_put_bignum(&buffer, key->rsa->d);
 119         buffer_put_bignum(&buffer, key->rsa->iqmp);
 120         buffer_put_bignum(&buffer, key->rsa->q);        /* reverse from SSL p */
 121         buffer_put_bignum(&buffer, key->rsa->p);        /* reverse from SSL q */
 122
 123         /* Pad the part to be encrypted until its size is a multiple of 8. */
 124         while (buffer_len(&buffer) % 8 != 0)
 125                 buffer_put_char(&buffer, 0);
 126
 127         /* This buffer will be used to contain the data in the file. */
 128         buffer_init(&encrypted);
 129
 130         /* First store keyfile id string. */
 131         for (i = 0; authfile_id_string[i]; i++)
 132                 buffer_put_char(&encrypted, authfile_id_string[i]);
 133         buffer_put_char(&encrypted, 0);
 134
 135         /* Store cipher type. */
 136         buffer_put_char(&encrypted, cipher_num);
 137         buffer_put_int(&encrypted, 0);  /* For future extension */
 138
 139         /* Store public key.  This will be in plain text. */
 140         buffer_put_int(&encrypted, BN_num_bits(key->rsa->n));
 141         buffer_put_bignum(&encrypted, key->rsa->n);
 142         buffer_put_bignum(&encrypted, key->rsa->e);
 143         buffer_put_cstring(&encrypted, comment);
 144
 145         /* Allocate space for the private part of the key in the buffer. */
 146         cp = buffer_append_space(&encrypted, buffer_len(&buffer));
 147
 148         cipher_set_key_string(&ciphercontext, cipher, passphrase,
 149             CIPHER_ENCRYPT);
 150         cipher_crypt(&ciphercontext, cp,
 151             buffer_ptr(&buffer), buffer_len(&buffer));
 152         cipher_cleanup(&ciphercontext);
 153         memset(&ciphercontext, 0, sizeof(ciphercontext));
 154
 155         /* Destroy temporary data. */
 156         memset(buf, 0, sizeof(buf));
 157         buffer_free(&buffer);
 158
 159         buffer_append(blob, buffer_ptr(&encrypted), buffer_len(&encrypted));
 160         buffer_free(&encrypted);
 161
 162         return 1;
 163 }
 164
 165 /* convert SSH v2 key in OpenSSL PEM format */
 166 static int
 167 key_private_pem_to_blob(Key *key, Buffer *blob, const char *_passphrase,
 168     const char *comment)
 169 {
 170         int success = 0;
 171         int blen, len = strlen(_passphrase);
 172         u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
 173 #if (OPENSSL_VERSION_NUMBER < 0x00907000L)
 174         const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL;
 175 #else
 176         const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL;
 177 #endif
 178         const u_char *bptr;
 179         BIO *bio;
 180
 181         if (len > 0 && len <= 4) {
 182                 error("passphrase too short: have %d bytes, need > 4", len);
 183                 return 0;
 184         }
 185         if ((bio = BIO_new(BIO_s_mem())) == NULL) {
 186                 error("%s: BIO_new failed", __func__);
 187                 return 0;
 188         }
 189         switch (key->type) {
 190         case KEY_DSA:
 191                 success = PEM_write_bio_DSAPrivateKey(bio, key->dsa,
 192                     cipher, passphrase, len, NULL, NULL);
 193                 break;
 194 #ifdef OPENSSL_HAS_ECC
 195         case KEY_ECDSA:
 196                 success = PEM_write_bio_ECPrivateKey(bio, key->ecdsa,
 197                     cipher, passphrase, len, NULL, NULL);
 198                 break;
 199 #endif
 200         case KEY_RSA:
 201                 success = PEM_write_bio_RSAPrivateKey(bio, key->rsa,
 202                     cipher, passphrase, len, NULL, NULL);
 203                 break;
 204         }
 205         if (success) {
 206                 if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0)
 207                         success = 0;
 208                 else
 209                         buffer_append(blob, bptr, blen);
 210         }
 211         BIO_free(bio);
 212         return success;
 213 }
 214
 215 /* Save a key blob to a file */
 216 static int
 217 key_save_private_blob(Buffer *keybuf, const char *filename)
 218 {
 219         int fd;
 220
 221         if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0) {
 222                 error("open %s failed: %s.", filename, strerror(errno));
 223                 return 0;
 224         }
 225         if (atomicio(vwrite, fd, buffer_ptr(keybuf),
 226             buffer_len(keybuf)) != buffer_len(keybuf)) {
 227                 error("write to key file %s failed: %s", filename,
 228                     strerror(errno));
 229                 close(fd);
 230                 unlink(filename);
 231                 return 0;
 232         }
 233         close(fd);
 234         return 1;
 235 }
 236
 237 /* Serialise "key" to buffer "blob" */
 238 static int
 239 key_private_to_blob(Key *key, Buffer *blob, const char *passphrase,
 240     const char *comment)
 241 {
 242         switch (key->type) {
 243         case KEY_RSA1:
 244                 return key_private_rsa1_to_blob(key, blob, passphrase, comment);
 245         case KEY_DSA:
 246         case KEY_ECDSA:
 247         case KEY_RSA:
 248                 return key_private_pem_to_blob(key, blob, passphrase, comment);
 249         default:
 250                 error("%s: cannot save key type %d", __func__, key->type);
 251                 return 0;
 252         }
 253 }
 254
 255 int
 256 key_save_private(Key *key, const char *filename, const char *passphrase,
 257     const char *comment)
 258 {
 259         Buffer keyblob;
 260         int success = 0;
 261
 262         buffer_init(&keyblob);
 263         if (!key_private_to_blob(key, &keyblob, passphrase, comment))
 264                 goto out;
 265         if (!key_save_private_blob(&keyblob, filename))
 266                 goto out;
 267         success = 1;
 268  out:
 269         buffer_free(&keyblob);
 270         return success;
 271 }
 272
 273 /*
 274  * Parse the public, unencrypted portion of a RSA1 key.
 275  */
 276 static Key *
 277 key_parse_public_rsa1(Buffer *blob, char **commentp)
 278 {
 279         Key *pub;
 280
 281         /* Check that it is at least big enough to contain the ID string. */
 282         if (buffer_len(blob) < sizeof(authfile_id_string)) {
 283                 debug3("Truncated RSA1 identifier");
 284                 return NULL;
 285         }
 286
 287         /*
 288          * Make sure it begins with the id string.  Consume the id string
 289          * from the buffer.
 290          */
 291         if (memcmp(buffer_ptr(blob), authfile_id_string,
 292             sizeof(authfile_id_string)) != 0) {
 293                 debug3("Incorrect RSA1 identifier");
 294                 return NULL;
 295         }
 296         buffer_consume(blob, sizeof(authfile_id_string));
 297
 298         /* Skip cipher type and reserved data. */
 299         (void) buffer_get_char(blob);   /* cipher type */
 300         (void) buffer_get_int(blob);            /* reserved */
 301
 302         /* Read the public key from the buffer. */
 303         (void) buffer_get_int(blob);
 304         pub = key_new(KEY_RSA1);
 305         buffer_get_bignum(blob, pub->rsa->n);
 306         buffer_get_bignum(blob, pub->rsa->e);
 307         if (commentp)
 308                 *commentp = buffer_get_string(blob, NULL);
 309         /* The encrypted private part is not parsed by this function. */
 310         buffer_clear(blob);
 311
 312         return pub;
 313 }
 314
 315 /* Load the contents of a key file into a buffer */
 316 static int
 317 key_load_file(int fd, const char *filename, Buffer *blob)
 318 {
 319         size_t len;
 320         u_char *cp;
 321         struct stat st;
 322
 323         if (fstat(fd, &st) < 0) {
 324                 error("%s: fstat of key file %.200s%sfailed: %.100s", __func__,
 325                     filename == NULL ? "" : filename,
 326                     filename == NULL ? "" : " ",
 327                     strerror(errno));
 328                 close(fd);
 329                 return 0;
 330         }
 331         if (st.st_size > 1*1024*1024) {
 332                 error("%s: key file %.200s%stoo large", __func__,
 333                     filename == NULL ? "" : filename,
 334                     filename == NULL ? "" : " ");
 335                 close(fd);
 336                 return 0;
 337         }
 338         len = (size_t)st.st_size;               /* truncated */
 339
 340         buffer_init(blob);
 341         cp = buffer_append_space(blob, len);
 342
 343         if (atomicio(read, fd, cp, len) != len) {
 344                 debug("%s: read from key file %.200s%sfailed: %.100s", __func__,
 345                     filename == NULL ? "" : filename,
 346                     filename == NULL ? "" : " ",
 347                     strerror(errno));
 348                 buffer_clear(blob);
 349                 close(fd);
 350                 return 0;
 351         }
 352         return 1;
 353 }
 354
 355 /*
 356  * Loads the public part of the ssh v1 key file.  Returns NULL if an error was
 357  * encountered (the file does not exist or is not readable), and the key
 358  * otherwise.
 359  */
 360 static Key *
 361 key_load_public_rsa1(int fd, const char *filename, char **commentp)
 362 {
 363         Buffer buffer;
 364         Key *pub;
 365
 366         buffer_init(&buffer);
 367         if (!key_load_file(fd, filename, &buffer)) {
 368                 buffer_free(&buffer);
 369                 return NULL;
 370         }
 371
 372         pub = key_parse_public_rsa1(&buffer, commentp);
 373         if (pub == NULL)
 374                 debug3("Could not load \"%s\" as a RSA1 public key", filename);
 375         buffer_free(&buffer);
 376         return pub;
 377 }
 378
 379 /* load public key from private-key file, works only for SSH v1 */
 380 Key *
 381 key_load_public_type(int type, const char *filename, char **commentp)
 382 {
 383         Key *pub;
 384         int fd;
 385
 386         if (type == KEY_RSA1) {
 387                 fd = open(filename, O_RDONLY);
 388                 if (fd < 0)
 389                         return NULL;
 390                 pub = key_load_public_rsa1(fd, filename, commentp);
 391                 close(fd);
 392                 return pub;
 393         }
 394         return NULL;
 395 }
 396
 397 static Key *
 398 key_parse_private_rsa1(Buffer *blob, const char *passphrase, char **commentp)
 399 {
 400         int check1, check2, cipher_type;
 401         Buffer decrypted;
 402         u_char *cp;
 403         CipherContext ciphercontext;
 404         Cipher *cipher;
 405         Key *prv = NULL;
 406
 407         /* Check that it is at least big enough to contain the ID string. */
 408         if (buffer_len(blob) < sizeof(authfile_id_string)) {
 409                 debug3("Truncated RSA1 identifier");
 410                 return NULL;
 411         }
 412
 413         /*
 414          * Make sure it begins with the id string.  Consume the id string
 415          * from the buffer.
 416          */
 417         if (memcmp(buffer_ptr(blob), authfile_id_string,
 418             sizeof(authfile_id_string)) != 0) {
 419                 debug3("Incorrect RSA1 identifier");
 420                 return NULL;
 421         }
 422         buffer_consume(blob, sizeof(authfile_id_string));
 423
 424         /* Read cipher type. */
 425         cipher_type = buffer_get_char(blob);
 426         (void) buffer_get_int(blob);    /* Reserved data. */
 427
 428         /* Read the public key from the buffer. */
 429         (void) buffer_get_int(blob);
 430         prv = key_new_private(KEY_RSA1);
 431
 432         buffer_get_bignum(blob, prv->rsa->n);
 433         buffer_get_bignum(blob, prv->rsa->e);
 434         if (commentp)
 435                 *commentp = buffer_get_string(blob, NULL);
 436         else
 437                 (void)buffer_get_string_ptr(blob, NULL);
 438
 439         /* Check that it is a supported cipher. */
 440         cipher = cipher_by_number(cipher_type);
 441         if (cipher == NULL) {
 442                 debug("Unsupported RSA1 cipher %d", cipher_type);
 443                 goto fail;
 444         }
 445         /* Initialize space for decrypted data. */
 446         buffer_init(&decrypted);
 447         cp = buffer_append_space(&decrypted, buffer_len(blob));
 448
 449         /* Rest of the buffer is encrypted.  Decrypt it using the passphrase. */
 450         cipher_set_key_string(&ciphercontext, cipher, passphrase,
 451             CIPHER_DECRYPT);
 452         cipher_crypt(&ciphercontext, cp,
 453             buffer_ptr(blob), buffer_len(blob));
 454         cipher_cleanup(&ciphercontext);
 455         memset(&ciphercontext, 0, sizeof(ciphercontext));
 456         buffer_clear(blob);
 457
 458         check1 = buffer_get_char(&decrypted);
 459         check2 = buffer_get_char(&decrypted);
 460         if (check1 != buffer_get_char(&decrypted) ||
 461             check2 != buffer_get_char(&decrypted)) {
 462                 if (strcmp(passphrase, "") != 0)
 463                         debug("Bad passphrase supplied for RSA1 key");
 464                 /* Bad passphrase. */
 465                 buffer_free(&decrypted);
 466                 goto fail;
 467         }
 468         /* Read the rest of the private key. */
 469         buffer_get_bignum(&decrypted, prv->rsa->d);
 470         buffer_get_bignum(&decrypted, prv->rsa->iqmp);          /* u */
 471         /* in SSL and SSH v1 p and q are exchanged */
 472         buffer_get_bignum(&decrypted, prv->rsa->q);             /* p */
 473         buffer_get_bignum(&decrypted, prv->rsa->p);             /* q */
 474
 475         /* calculate p-1 and q-1 */
 476         rsa_generate_additional_parameters(prv->rsa);
 477
 478         buffer_free(&decrypted);
 479
 480         /* enable blinding */
 481         if (RSA_blinding_on(prv->rsa, NULL) != 1) {
 482                 error("%s: RSA_blinding_on failed", __func__);
 483                 goto fail;
 484         }
 485         return prv;
 486
 487 fail:
 488         if (commentp)
 489                 xfree(*commentp);
 490         key_free(prv);
 491         return NULL;
 492 }
 493
 494 static Key *
 495 key_parse_private_pem(Buffer *blob, int type, const char *passphrase,
 496     char **commentp)
 497 {
 498         EVP_PKEY *pk = NULL;
 499         Key *prv = NULL;
 500         char *name = "<no key>";
 501         BIO *bio;
 502
 503         if ((bio = BIO_new_mem_buf(buffer_ptr(blob),
 504             buffer_len(blob))) == NULL) {
 505                 error("%s: BIO_new_mem_buf failed", __func__);
 506                 return NULL;
 507         }
 508
 509         pk = PEM_read_bio_PrivateKey(bio, NULL, NULL, (char *)passphrase);
 510         BIO_free(bio);
 511         if (pk == NULL) {
 512                 debug("%s: PEM_read_PrivateKey failed", __func__);
 513                 (void)ERR_get_error();
 514         } else if (pk->type == EVP_PKEY_RSA &&
 515             (type == KEY_UNSPEC||type==KEY_RSA)) {
 516                 prv = key_new(KEY_UNSPEC);
 517                 prv->rsa = EVP_PKEY_get1_RSA(pk);
 518                 prv->type = KEY_RSA;
 519                 name = "rsa w/o comment";
 520 #ifdef DEBUG_PK
 521                 RSA_print_fp(stderr, prv->rsa, 8);
 522 #endif
 523                 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
 524                         error("%s: RSA_blinding_on failed", __func__);
 525                         key_free(prv);
 526                         prv = NULL;
 527                 }
 528         } else if (pk->type == EVP_PKEY_DSA &&
 529             (type == KEY_UNSPEC||type==KEY_DSA)) {
 530                 prv = key_new(KEY_UNSPEC);
 531                 prv->dsa = EVP_PKEY_get1_DSA(pk);
 532                 prv->type = KEY_DSA;
 533                 name = "dsa w/o comment";
 534 #ifdef DEBUG_PK
 535                 DSA_print_fp(stderr, prv->dsa, 8);
 536 #endif
 537 #ifdef OPENSSL_HAS_ECC
 538         } else if (pk->type == EVP_PKEY_EC &&
 539             (type == KEY_UNSPEC||type==KEY_ECDSA)) {
 540                 prv = key_new(KEY_UNSPEC);
 541                 prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk);
 542                 prv->type = KEY_ECDSA;
 543                 if ((prv->ecdsa_nid = key_ecdsa_key_to_nid(prv->ecdsa)) == -1 ||
 544                     key_curve_nid_to_name(prv->ecdsa_nid) == NULL ||
 545                     key_ec_validate_public(EC_KEY_get0_group(prv->ecdsa),
 546                     EC_KEY_get0_public_key(prv->ecdsa)) != 0 ||
 547                     key_ec_validate_private(prv->ecdsa) != 0) {
 548                         error("%s: bad ECDSA key", __func__);
 549                         key_free(prv);
 550                         prv = NULL;
 551                 }
 552                 name = "ecdsa w/o comment";
 553 #ifdef DEBUG_PK
 554                 if (prv != NULL && prv->ecdsa != NULL)
 555                         key_dump_ec_key(prv->ecdsa);
 556 #endif
 557 #endif /* OPENSSL_HAS_ECC */
 558         } else {
 559                 error("%s: PEM_read_PrivateKey: mismatch or "
 560                     "unknown EVP_PKEY save_type %d", __func__, pk->save_type);
 561         }
 562         if (pk != NULL)
 563                 EVP_PKEY_free(pk);
 564         if (prv != NULL && commentp)
 565                 *commentp = xstrdup(name);
 566         debug("read PEM private key done: type %s",
 567             prv ? key_type(prv) : "<unknown>");
 568         return prv;
 569 }
 570
 571 Key *
 572 key_load_private_pem(int fd, int type, const char *passphrase,
 573     char **commentp)
 574 {
 575         Buffer buffer;
 576         Key *prv;
 577
 578         buffer_init(&buffer);
 579         if (!key_load_file(fd, NULL, &buffer)) {
 580                 buffer_free(&buffer);
 581                 return NULL;
 582         }
 583         prv = key_parse_private_pem(&buffer, type, passphrase, commentp);
 584         buffer_free(&buffer);
 585         return prv;
 586 }
 587
 588 int
 589 key_perm_ok(int fd, const char *filename)
 590 {
 591         struct stat st;
 592
 593         if (fstat(fd, &st) < 0)
 594                 return 0;
 595         /*
 596          * if a key owned by the user is accessed, then we check the
 597          * permissions of the file. if the key owned by a different user,
 598          * then we don't care.
 599          */
 600 #ifdef HAVE_CYGWIN
 601         if (check_ntsec(filename))
 602 #endif
 603         if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
 604                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 605                 error("@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @");
 606                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 607                 error("Permissions 0%3.3o for '%s' are too open.",
 608                     (u_int)st.st_mode & 0777, filename);
 609                 error("It is recommended that your private key files are NOT accessible by others.");
 610                 error("This private key will be ignored.");
 611                 return 0;
 612         }
 613         return 1;
 614 }
 615
 616 static Key *
 617 key_parse_private_type(Buffer *blob, int type, const char *passphrase,
 618     char **commentp)
 619 {
 620         switch (type) {
 621         case KEY_RSA1:
 622                 return key_parse_private_rsa1(blob, passphrase, commentp);
 623         case KEY_DSA:
 624         case KEY_ECDSA:
 625         case KEY_RSA:
 626         case KEY_UNSPEC:
 627                 return key_parse_private_pem(blob, type, passphrase, commentp);
 628         default:
 629                 break;
 630         }
 631         return NULL;
 632 }
 633
 634 Key *
 635 key_load_private_type(int type, const char *filename, const char *passphrase,
 636     char **commentp, int *perm_ok)
 637 {
 638         int fd;
 639         Key *ret;
 640         Buffer buffer;
 641
 642         fd = open(filename, O_RDONLY);
 643         if (fd < 0) {
 644                 debug("could not open key file '%s': %s", filename,
 645                     strerror(errno));
 646                 if (perm_ok != NULL)
 647                         *perm_ok = 0;
 648                 return NULL;
 649         }
 650         if (!key_perm_ok(fd, filename)) {
 651                 if (perm_ok != NULL)
 652                         *perm_ok = 0;
 653                 error("bad permissions: ignore key: %s", filename);
 654                 close(fd);
 655                 return NULL;
 656         }
 657         if (perm_ok != NULL)
 658                 *perm_ok = 1;
 659
 660         buffer_init(&buffer);
 661         if (!key_load_file(fd, filename, &buffer)) {
 662                 buffer_free(&buffer);
 663                 close(fd);
 664                 return NULL;
 665         }
 666         close(fd);
 667         ret = key_parse_private_type(&buffer, type, passphrase, commentp);
 668         buffer_free(&buffer);
 669         return ret;
 670 }
 671
 672 Key *
 673 key_load_private(const char *filename, const char *passphrase,
 674     char **commentp)
 675 {
 676         Key *pub, *prv;
 677         Buffer buffer, pubcopy;
 678         int fd;
 679
 680         fd = open(filename, O_RDONLY);
 681         if (fd < 0) {
 682                 debug("could not open key file '%s': %s", filename,
 683                     strerror(errno));
 684                 return NULL;
 685         }
 686         if (!key_perm_ok(fd, filename)) {
 687                 error("bad permissions: ignore key: %s", filename);
 688                 close(fd);
 689                 return NULL;
 690         }
 691
 692         buffer_init(&buffer);
 693         if (!key_load_file(fd, filename, &buffer)) {
 694                 buffer_free(&buffer);
 695                 close(fd);
 696                 return NULL;
 697         }
 698         close(fd);
 699
 700         buffer_init(&pubcopy);
 701         buffer_append(&pubcopy, buffer_ptr(&buffer), buffer_len(&buffer));
 702         /* it's a SSH v1 key if the public key part is readable */
 703         pub = key_parse_public_rsa1(&pubcopy, commentp);
 704         buffer_free(&pubcopy);
 705         if (pub == NULL) {
 706                 prv = key_parse_private_type(&buffer, KEY_UNSPEC,
 707                     passphrase, NULL);
 708                 /* use the filename as a comment for PEM */
 709                 if (commentp && prv)
 710                         *commentp = xstrdup(filename);
 711         } else {
 712                 key_free(pub);
 713                 /* key_parse_public_rsa1() has already loaded the comment */
 714                 prv = key_parse_private_type(&buffer, KEY_RSA1, passphrase,
 715                     NULL);
 716         }
 717         buffer_free(&buffer);
 718         return prv;
 719 }
 720
 721 static int
 722 key_try_load_public(Key *k, const char *filename, char **commentp)
 723 {
 724         FILE *f;
 725         char line[SSH_MAX_PUBKEY_BYTES];
 726         char *cp;
 727         u_long linenum = 0;
 728
 729         f = fopen(filename, "r");
 730         if (f != NULL) {
 731                 while (read_keyfile_line(f, filename, line, sizeof(line),
 732                             &linenum) != -1) {
 733                         cp = line;
 734                         switch (*cp) {
 735                         case '#':
 736                         case '\n':
 737                         case '\0':
 738                                 continue;
 739                         }
 740                         /* Skip leading whitespace. */
 741                         for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
 742                                 ;
 743                         if (*cp) {
 744                                 if (key_read(k, &cp) == 1) {
 745                                         if (commentp)
 746                                                 *commentp=xstrdup(filename);
 747                                         fclose(f);
 748                                         return 1;
 749                                 }
 750                         }
 751                 }
 752                 fclose(f);
 753         }
 754         return 0;
 755 }
 756
 757 /* load public key from ssh v1 private or any pubkey file */
 758 Key *
 759 key_load_public(const char *filename, char **commentp)
 760 {
 761         Key *pub;
 762         char file[MAXPATHLEN];
 763
 764         /* try rsa1 private key */
 765         pub = key_load_public_type(KEY_RSA1, filename, commentp);
 766         if (pub != NULL)
 767                 return pub;
 768
 769         /* try rsa1 public key */
 770         pub = key_new(KEY_RSA1);
 771         if (key_try_load_public(pub, filename, commentp) == 1)
 772                 return pub;
 773         key_free(pub);
 774
 775         /* try ssh2 public key */
 776         pub = key_new(KEY_UNSPEC);
 777         if (key_try_load_public(pub, filename, commentp) == 1)
 778                 return pub;
 779         if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
 780             (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
 781             (key_try_load_public(pub, file, commentp) == 1))
 782                 return pub;
 783         key_free(pub);
 784         return NULL;
 785 }
 786
 787 /* Load the certificate associated with the named private key */
 788 Key *
 789 key_load_cert(const char *filename)
 790 {
 791         Key *pub;
 792         char *file;
 793
 794         pub = key_new(KEY_UNSPEC);
 795         xasprintf(&file, "%s-cert.pub", filename);
 796         if (key_try_load_public(pub, file, NULL) == 1) {
 797                 xfree(file);
 798                 return pub;
 799         }
 800         xfree(file);
 801         key_free(pub);
 802         return NULL;
 803 }
 804
 805 /* Load private key and certificate */
 806 Key *
 807 key_load_private_cert(int type, const char *filename, const char *passphrase,
 808     int *perm_ok)
 809 {
 810         Key *key, *pub;
 811
 812         switch (type) {
 813         case KEY_RSA:
 814         case KEY_DSA:
 815         case KEY_ECDSA:
 816                 break;
 817         default:
 818                 error("%s: unsupported key type", __func__);
 819                 return NULL;
 820         }
 821
 822         if ((key = key_load_private_type(type, filename,
 823             passphrase, NULL, perm_ok)) == NULL)
 824                 return NULL;
 825
 826         if ((pub = key_load_cert(filename)) == NULL) {
 827                 key_free(key);
 828                 return NULL;
 829         }
 830
 831         /* Make sure the private key matches the certificate */
 832         if (key_equal_public(key, pub) == 0) {
 833                 error("%s: certificate does not match private key %s",
 834                     __func__, filename);
 835         } else if (key_to_certified(key, key_cert_is_legacy(pub)) != 0) {
 836                 error("%s: key_to_certified failed", __func__);
 837         } else {
 838                 key_cert_copy(pub, key);
 839                 key_free(pub);
 840                 return key;
 841         }
 842
 843         key_free(key);
 844         key_free(pub);
 845         return NULL;
 846 }
 847
 848 /*
 849  * Returns 1 if the specified "key" is listed in the file "filename",
 850  * 0 if the key is not listed or -1 on error.
 851  * If strict_type is set then the key type must match exactly,
 852  * otherwise a comparison that ignores certficiate data is performed.
 853  */
 854 int
 855 key_in_file(Key *key, const char *filename, int strict_type)
 856 {
 857         FILE *f;
 858         char line[SSH_MAX_PUBKEY_BYTES];
 859         char *cp;
 860         u_long linenum = 0;
 861         int ret = 0;
 862         Key *pub;
 863         int (*key_compare)(const Key *, const Key *) = strict_type ?
 864             key_equal : key_equal_public;
 865
 866         if ((f = fopen(filename, "r")) == NULL) {
 867                 if (errno == ENOENT) {
 868                         debug("%s: keyfile \"%s\" missing", __func__, filename);
 869                         return 0;
 870                 } else {
 871                         error("%s: could not open keyfile \"%s\": %s", __func__,
 872                             filename, strerror(errno));
 873                         return -1;
 874                 }
 875         }
 876
 877         while (read_keyfile_line(f, filename, line, sizeof(line),
 878                     &linenum) != -1) {
 879                 cp = line;
 880
 881                 /* Skip leading whitespace. */
 882                 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
 883                         ;
 884
 885                 /* Skip comments and empty lines */
 886                 switch (*cp) {
 887                 case '#':
 888                 case '\n':
 889                 case '\0':
 890                         continue;
 891                 }
 892
 893                 pub = key_new(KEY_UNSPEC);
 894                 if (key_read(pub, &cp) != 1) {
 895                         key_free(pub);
 896                         continue;
 897                 }
 898                 if (key_compare(key, pub)) {
 899                         ret = 1;
 900                         key_free(pub);
 901                         break;
 902                 }
 903                 key_free(pub);
 904         }
 905         fclose(f);
 906         return ret;
 907 }
 908