authfile.c

   1 /* $OpenBSD: authfile.c,v 1.85 2010/10/28 11:22:09 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 #ifdef OPENSSL_HAS_ECC
 217         case KEY_ECDSA:
 218                 success = PEM_write_ECPrivateKey(fp, key->ecdsa,
 219                     cipher, passphrase, len, NULL, NULL);
 220                 break;
 221 #endif
 222         case KEY_RSA:
 223                 success = PEM_write_RSAPrivateKey(fp, key->rsa,
 224                     cipher, passphrase, len, NULL, NULL);
 225                 break;
 226         }
 227         fclose(fp);
 228         return success;
 229 }
 230
 231 int
 232 key_save_private(Key *key, const char *filename, const char *passphrase,
 233     const char *comment)
 234 {
 235         switch (key->type) {
 236         case KEY_RSA1:
 237                 return key_save_private_rsa1(key, filename, passphrase,
 238                     comment);
 239         case KEY_DSA:
 240         case KEY_ECDSA:
 241         case KEY_RSA:
 242                 return key_save_private_pem(key, filename, passphrase,
 243                     comment);
 244         default:
 245                 break;
 246         }
 247         error("key_save_private: cannot save key type %d", key->type);
 248         return 0;
 249 }
 250
 251 /*
 252  * Loads the public part of the ssh v1 key file.  Returns NULL if an error was
 253  * encountered (the file does not exist or is not readable), and the key
 254  * otherwise.
 255  */
 256
 257 static Key *
 258 key_load_public_rsa1(int fd, const char *filename, char **commentp)
 259 {
 260         Buffer buffer;
 261         Key *pub;
 262         struct stat st;
 263         char *cp;
 264         u_int i;
 265         size_t len;
 266
 267         if (fstat(fd, &st) < 0) {
 268                 error("fstat for key file %.200s failed: %.100s",
 269                     filename, strerror(errno));
 270                 return NULL;
 271         }
 272         if (st.st_size > 1*1024*1024) {
 273                 error("key file %.200s too large", filename);
 274                 return NULL;
 275         }
 276         len = (size_t)st.st_size;               /* truncated */
 277
 278         buffer_init(&buffer);
 279         cp = buffer_append_space(&buffer, len);
 280
 281         if (atomicio(read, fd, cp, len) != len) {
 282                 debug("Read from key file %.200s failed: %.100s", filename,
 283                     strerror(errno));
 284                 buffer_free(&buffer);
 285                 return NULL;
 286         }
 287
 288         /* Check that it is at least big enough to contain the ID string. */
 289         if (len < sizeof(authfile_id_string)) {
 290                 debug3("Not a RSA1 key file %.200s.", filename);
 291                 buffer_free(&buffer);
 292                 return NULL;
 293         }
 294         /*
 295          * Make sure it begins with the id string.  Consume the id string
 296          * from the buffer.
 297          */
 298         for (i = 0; i < sizeof(authfile_id_string); i++)
 299                 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
 300                         debug3("Not a RSA1 key file %.200s.", filename);
 301                         buffer_free(&buffer);
 302                         return NULL;
 303                 }
 304         /* Skip cipher type and reserved data. */
 305         (void) buffer_get_char(&buffer);        /* cipher type */
 306         (void) buffer_get_int(&buffer);         /* reserved */
 307
 308         /* Read the public key from the buffer. */
 309         (void) buffer_get_int(&buffer);
 310         pub = key_new(KEY_RSA1);
 311         buffer_get_bignum(&buffer, pub->rsa->n);
 312         buffer_get_bignum(&buffer, pub->rsa->e);
 313         if (commentp)
 314                 *commentp = buffer_get_string(&buffer, NULL);
 315         /* The encrypted private part is not parsed by this function. */
 316
 317         buffer_free(&buffer);
 318         return pub;
 319 }
 320
 321 /* load public key from private-key file, works only for SSH v1 */
 322 Key *
 323 key_load_public_type(int type, const char *filename, char **commentp)
 324 {
 325         Key *pub;
 326         int fd;
 327
 328         if (type == KEY_RSA1) {
 329                 fd = open(filename, O_RDONLY);
 330                 if (fd < 0)
 331                         return NULL;
 332                 pub = key_load_public_rsa1(fd, filename, commentp);
 333                 close(fd);
 334                 return pub;
 335         }
 336         return NULL;
 337 }
 338
 339 /*
 340  * Loads the private key from the file.  Returns 0 if an error is encountered
 341  * (file does not exist or is not readable, or passphrase is bad). This
 342  * initializes the private key.
 343  * Assumes we are called under uid of the owner of the file.
 344  */
 345
 346 static Key *
 347 key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
 348     char **commentp)
 349 {
 350         u_int i;
 351         int check1, check2, cipher_type;
 352         size_t len;
 353         Buffer buffer, decrypted;
 354         u_char *cp;
 355         CipherContext ciphercontext;
 356         Cipher *cipher;
 357         Key *prv = NULL;
 358         struct stat st;
 359
 360         if (fstat(fd, &st) < 0) {
 361                 error("fstat for key file %.200s failed: %.100s",
 362                     filename, strerror(errno));
 363                 close(fd);
 364                 return NULL;
 365         }
 366         if (st.st_size > 1*1024*1024) {
 367                 error("key file %.200s too large", filename);
 368                 close(fd);
 369                 return (NULL);
 370         }
 371         len = (size_t)st.st_size;               /* truncated */
 372
 373         buffer_init(&buffer);
 374         cp = buffer_append_space(&buffer, len);
 375
 376         if (atomicio(read, fd, cp, len) != len) {
 377                 debug("Read from key file %.200s failed: %.100s", filename,
 378                     strerror(errno));
 379                 buffer_free(&buffer);
 380                 close(fd);
 381                 return NULL;
 382         }
 383
 384         /* Check that it is at least big enough to contain the ID string. */
 385         if (len < sizeof(authfile_id_string)) {
 386                 debug3("Not a RSA1 key file %.200s.", filename);
 387                 buffer_free(&buffer);
 388                 close(fd);
 389                 return NULL;
 390         }
 391         /*
 392          * Make sure it begins with the id string.  Consume the id string
 393          * from the buffer.
 394          */
 395         for (i = 0; i < sizeof(authfile_id_string); i++)
 396                 if (buffer_get_char(&buffer) != authfile_id_string[i]) {
 397                         debug3("Not a RSA1 key file %.200s.", filename);
 398                         buffer_free(&buffer);
 399                         close(fd);
 400                         return NULL;
 401                 }
 402
 403         /* Read cipher type. */
 404         cipher_type = buffer_get_char(&buffer);
 405         (void) buffer_get_int(&buffer); /* Reserved data. */
 406
 407         /* Read the public key from the buffer. */
 408         (void) buffer_get_int(&buffer);
 409         prv = key_new_private(KEY_RSA1);
 410
 411         buffer_get_bignum(&buffer, prv->rsa->n);
 412         buffer_get_bignum(&buffer, prv->rsa->e);
 413         if (commentp)
 414                 *commentp = buffer_get_string(&buffer, NULL);
 415         else
 416                 xfree(buffer_get_string(&buffer, NULL));
 417
 418         /* Check that it is a supported cipher. */
 419         cipher = cipher_by_number(cipher_type);
 420         if (cipher == NULL) {
 421                 debug("Unsupported cipher %d used in key file %.200s.",
 422                     cipher_type, filename);
 423                 buffer_free(&buffer);
 424                 goto fail;
 425         }
 426         /* Initialize space for decrypted data. */
 427         buffer_init(&decrypted);
 428         cp = buffer_append_space(&decrypted, buffer_len(&buffer));
 429
 430         /* Rest of the buffer is encrypted.  Decrypt it using the passphrase. */
 431         cipher_set_key_string(&ciphercontext, cipher, passphrase,
 432             CIPHER_DECRYPT);
 433         cipher_crypt(&ciphercontext, cp,
 434             buffer_ptr(&buffer), buffer_len(&buffer));
 435         cipher_cleanup(&ciphercontext);
 436         memset(&ciphercontext, 0, sizeof(ciphercontext));
 437         buffer_free(&buffer);
 438
 439         check1 = buffer_get_char(&decrypted);
 440         check2 = buffer_get_char(&decrypted);
 441         if (check1 != buffer_get_char(&decrypted) ||
 442             check2 != buffer_get_char(&decrypted)) {
 443                 if (strcmp(passphrase, "") != 0)
 444                         debug("Bad passphrase supplied for key file %.200s.",
 445                             filename);
 446                 /* Bad passphrase. */
 447                 buffer_free(&decrypted);
 448                 goto fail;
 449         }
 450         /* Read the rest of the private key. */
 451         buffer_get_bignum(&decrypted, prv->rsa->d);
 452         buffer_get_bignum(&decrypted, prv->rsa->iqmp);          /* u */
 453         /* in SSL and SSH v1 p and q are exchanged */
 454         buffer_get_bignum(&decrypted, prv->rsa->q);             /* p */
 455         buffer_get_bignum(&decrypted, prv->rsa->p);             /* q */
 456
 457         /* calculate p-1 and q-1 */
 458         rsa_generate_additional_parameters(prv->rsa);
 459
 460         buffer_free(&decrypted);
 461
 462         /* enable blinding */
 463         if (RSA_blinding_on(prv->rsa, NULL) != 1) {
 464                 error("key_load_private_rsa1: RSA_blinding_on failed");
 465                 goto fail;
 466         }
 467         close(fd);
 468         return prv;
 469
 470 fail:
 471         if (commentp)
 472                 xfree(*commentp);
 473         close(fd);
 474         key_free(prv);
 475         return NULL;
 476 }
 477
 478 Key *
 479 key_load_private_pem(int fd, int type, const char *passphrase,
 480     char **commentp)
 481 {
 482         FILE *fp;
 483         EVP_PKEY *pk = NULL;
 484         Key *prv = NULL;
 485         char *name = "<no key>";
 486
 487         fp = fdopen(fd, "r");
 488         if (fp == NULL) {
 489                 error("fdopen failed: %s", strerror(errno));
 490                 close(fd);
 491                 return NULL;
 492         }
 493         pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase);
 494         if (pk == NULL) {
 495                 debug("PEM_read_PrivateKey failed");
 496                 (void)ERR_get_error();
 497         } else if (pk->type == EVP_PKEY_RSA &&
 498             (type == KEY_UNSPEC||type==KEY_RSA)) {
 499                 prv = key_new(KEY_UNSPEC);
 500                 prv->rsa = EVP_PKEY_get1_RSA(pk);
 501                 prv->type = KEY_RSA;
 502                 name = "rsa w/o comment";
 503 #ifdef DEBUG_PK
 504                 RSA_print_fp(stderr, prv->rsa, 8);
 505 #endif
 506                 if (RSA_blinding_on(prv->rsa, NULL) != 1) {
 507                         error("key_load_private_pem: RSA_blinding_on failed");
 508                         key_free(prv);
 509                         prv = NULL;
 510                 }
 511         } else if (pk->type == EVP_PKEY_DSA &&
 512             (type == KEY_UNSPEC||type==KEY_DSA)) {
 513                 prv = key_new(KEY_UNSPEC);
 514                 prv->dsa = EVP_PKEY_get1_DSA(pk);
 515                 prv->type = KEY_DSA;
 516                 name = "dsa w/o comment";
 517 #ifdef DEBUG_PK
 518                 DSA_print_fp(stderr, prv->dsa, 8);
 519 #endif
 520 #ifdef OPENSSL_HAS_ECC
 521         } else if (pk->type == EVP_PKEY_EC &&
 522             (type == KEY_UNSPEC||type==KEY_ECDSA)) {
 523                 prv = key_new(KEY_UNSPEC);
 524                 prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk);
 525                 prv->type = KEY_ECDSA;
 526                 if ((prv->ecdsa_nid = key_ecdsa_key_to_nid(prv->ecdsa)) == -1 ||
 527                     key_curve_nid_to_name(prv->ecdsa_nid) == NULL ||
 528                     key_ec_validate_public(EC_KEY_get0_group(prv->ecdsa),
 529                     EC_KEY_get0_public_key(prv->ecdsa)) != 0 ||
 530                     key_ec_validate_private(prv->ecdsa) != 0) {
 531                         error("%s: bad ECDSA key", __func__);
 532                         key_free(prv);
 533                         prv = NULL;
 534                 }
 535                 name = "ecdsa w/o comment";
 536 #ifdef DEBUG_PK
 537                 if (prv != NULL && prv->ecdsa != NULL)
 538                         key_dump_ec_key(prv->ecdsa);
 539 #endif
 540 #endif /* OPENSSL_HAS_ECC */
 541         } else {
 542                 error("PEM_read_PrivateKey: mismatch or "
 543                     "unknown EVP_PKEY save_type %d", pk->save_type);
 544         }
 545         fclose(fp);
 546         if (pk != NULL)
 547                 EVP_PKEY_free(pk);
 548         if (prv != NULL && commentp)
 549                 *commentp = xstrdup(name);
 550         debug("read PEM private key done: type %s",
 551             prv ? key_type(prv) : "<unknown>");
 552         return prv;
 553 }
 554
 555 int
 556 key_perm_ok(int fd, const char *filename)
 557 {
 558         struct stat st;
 559
 560         if (fstat(fd, &st) < 0)
 561                 return 0;
 562         /*
 563          * if a key owned by the user is accessed, then we check the
 564          * permissions of the file. if the key owned by a different user,
 565          * then we don't care.
 566          */
 567 #ifdef HAVE_CYGWIN
 568         if (check_ntsec(filename))
 569 #endif
 570         if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) {
 571                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 572                 error("@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @");
 573                 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 574                 error("Permissions 0%3.3o for '%s' are too open.",
 575                     (u_int)st.st_mode & 0777, filename);
 576                 error("It is recommended that your private key files are NOT accessible by others.");
 577                 error("This private key will be ignored.");
 578                 return 0;
 579         }
 580         return 1;
 581 }
 582
 583 Key *
 584 key_load_private_type(int type, const char *filename, const char *passphrase,
 585     char **commentp, int *perm_ok)
 586 {
 587         int fd;
 588
 589         fd = open(filename, O_RDONLY);
 590         if (fd < 0) {
 591                 debug("could not open key file '%s': %s", filename,
 592                     strerror(errno));
 593                 if (perm_ok != NULL)
 594                         *perm_ok = 0;
 595                 return NULL;
 596         }
 597         if (!key_perm_ok(fd, filename)) {
 598                 if (perm_ok != NULL)
 599                         *perm_ok = 0;
 600                 error("bad permissions: ignore key: %s", filename);
 601                 close(fd);
 602                 return NULL;
 603         }
 604         if (perm_ok != NULL)
 605                 *perm_ok = 1;
 606         switch (type) {
 607         case KEY_RSA1:
 608                 return key_load_private_rsa1(fd, filename, passphrase,
 609                     commentp);
 610                 /* closes fd */
 611         case KEY_DSA:
 612         case KEY_ECDSA:
 613         case KEY_RSA:
 614         case KEY_UNSPEC:
 615                 return key_load_private_pem(fd, type, passphrase, commentp);
 616                 /* closes fd */
 617         default:
 618                 close(fd);
 619                 break;
 620         }
 621         return NULL;
 622 }
 623
 624 Key *
 625 key_load_private(const char *filename, const char *passphrase,
 626     char **commentp)
 627 {
 628         Key *pub, *prv;
 629         int fd;
 630
 631         fd = open(filename, O_RDONLY);
 632         if (fd < 0) {
 633                 debug("could not open key file '%s': %s", filename,
 634                     strerror(errno));
 635                 return NULL;
 636         }
 637         if (!key_perm_ok(fd, filename)) {
 638                 error("bad permissions: ignore key: %s", filename);
 639                 close(fd);
 640                 return NULL;
 641         }
 642         pub = key_load_public_rsa1(fd, filename, commentp);
 643         lseek(fd, (off_t) 0, SEEK_SET);         /* rewind */
 644         if (pub == NULL) {
 645                 /* closes fd */
 646                 prv = key_load_private_pem(fd, KEY_UNSPEC, passphrase, NULL);
 647                 /* use the filename as a comment for PEM */
 648                 if (commentp && prv)
 649                         *commentp = xstrdup(filename);
 650         } else {
 651                 /* it's a SSH v1 key if the public key part is readable */
 652                 key_free(pub);
 653                 /* closes fd */
 654                 prv = key_load_private_rsa1(fd, filename, passphrase, NULL);
 655         }
 656         return prv;
 657 }
 658
 659 static int
 660 key_try_load_public(Key *k, const char *filename, char **commentp)
 661 {
 662         FILE *f;
 663         char line[SSH_MAX_PUBKEY_BYTES];
 664         char *cp;
 665         u_long linenum = 0;
 666
 667         f = fopen(filename, "r");
 668         if (f != NULL) {
 669                 while (read_keyfile_line(f, filename, line, sizeof(line),
 670                             &linenum) != -1) {
 671                         cp = line;
 672                         switch (*cp) {
 673                         case '#':
 674                         case '\n':
 675                         case '\0':
 676                                 continue;
 677                         }
 678                         /* Skip leading whitespace. */
 679                         for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
 680                                 ;
 681                         if (*cp) {
 682                                 if (key_read(k, &cp) == 1) {
 683                                         if (commentp)
 684                                                 *commentp=xstrdup(filename);
 685                                         fclose(f);
 686                                         return 1;
 687                                 }
 688                         }
 689                 }
 690                 fclose(f);
 691         }
 692         return 0;
 693 }
 694
 695 /* load public key from ssh v1 private or any pubkey file */
 696 Key *
 697 key_load_public(const char *filename, char **commentp)
 698 {
 699         Key *pub;
 700         char file[MAXPATHLEN];
 701
 702         /* try rsa1 private key */
 703         pub = key_load_public_type(KEY_RSA1, filename, commentp);
 704         if (pub != NULL)
 705                 return pub;
 706
 707         /* try rsa1 public key */
 708         pub = key_new(KEY_RSA1);
 709         if (key_try_load_public(pub, filename, commentp) == 1)
 710                 return pub;
 711         key_free(pub);
 712
 713         /* try ssh2 public key */
 714         pub = key_new(KEY_UNSPEC);
 715         if (key_try_load_public(pub, filename, commentp) == 1)
 716                 return pub;
 717         if ((strlcpy(file, filename, sizeof file) < sizeof(file)) &&
 718             (strlcat(file, ".pub", sizeof file) < sizeof(file)) &&
 719             (key_try_load_public(pub, file, commentp) == 1))
 720                 return pub;
 721         key_free(pub);
 722         return NULL;
 723 }
 724
 725 /* Load the certificate associated with the named private key */
 726 Key *
 727 key_load_cert(const char *filename)
 728 {
 729         Key *pub;
 730         char *file;
 731
 732         pub = key_new(KEY_UNSPEC);
 733         xasprintf(&file, "%s-cert.pub", filename);
 734         if (key_try_load_public(pub, file, NULL) == 1) {
 735                 xfree(file);
 736                 return pub;
 737         }
 738         xfree(file);
 739         key_free(pub);
 740         return NULL;
 741 }
 742
 743 /* Load private key and certificate */
 744 Key *
 745 key_load_private_cert(int type, const char *filename, const char *passphrase,
 746     int *perm_ok)
 747 {
 748         Key *key, *pub;
 749
 750         switch (type) {
 751         case KEY_RSA:
 752         case KEY_DSA:
 753         case KEY_ECDSA:
 754                 break;
 755         default:
 756                 error("%s: unsupported key type", __func__);
 757                 return NULL;
 758         }
 759
 760         if ((key = key_load_private_type(type, filename,
 761             passphrase, NULL, perm_ok)) == NULL)
 762                 return NULL;
 763
 764         if ((pub = key_load_cert(filename)) == NULL) {
 765                 key_free(key);
 766                 return NULL;
 767         }
 768
 769         /* Make sure the private key matches the certificate */
 770         if (key_equal_public(key, pub) == 0) {
 771                 error("%s: certificate does not match private key %s",
 772                     __func__, filename);
 773         } else if (key_to_certified(key, key_cert_is_legacy(pub)) != 0) {
 774                 error("%s: key_to_certified failed", __func__);
 775         } else {
 776                 key_cert_copy(pub, key);
 777                 key_free(pub);
 778                 return key;
 779         }
 780
 781         key_free(key);
 782         key_free(pub);
 783         return NULL;
 784 }
 785
 786 /*
 787  * Returns 1 if the specified "key" is listed in the file "filename",
 788  * 0 if the key is not listed or -1 on error.
 789  * If strict_type is set then the key type must match exactly,
 790  * otherwise a comparison that ignores certficiate data is performed.
 791  */
 792 int
 793 key_in_file(Key *key, const char *filename, int strict_type)
 794 {
 795         FILE *f;
 796         char line[SSH_MAX_PUBKEY_BYTES];
 797         char *cp;
 798         u_long linenum = 0;
 799         int ret = 0;
 800         Key *pub;
 801         int (*key_compare)(const Key *, const Key *) = strict_type ?
 802             key_equal : key_equal_public;
 803
 804         if ((f = fopen(filename, "r")) == NULL) {
 805                 if (errno == ENOENT) {
 806                         debug("%s: keyfile \"%s\" missing", __func__, filename);
 807                         return 0;
 808                 } else {
 809                         error("%s: could not open keyfile \"%s\": %s", __func__,
 810                             filename, strerror(errno));
 811                         return -1;
 812                 }
 813         }
 814
 815         while (read_keyfile_line(f, filename, line, sizeof(line),
 816                     &linenum) != -1) {
 817                 cp = line;
 818
 819                 /* Skip leading whitespace. */
 820                 for (; *cp && (*cp == ' ' || *cp == '\t'); cp++)
 821                         ;
 822
 823                 /* Skip comments and empty lines */
 824                 switch (*cp) {
 825                 case '#':
 826                 case '\n':
 827                 case '\0':
 828                         continue;
 829                 }
 830
 831                 pub = key_new(KEY_UNSPEC);
 832                 if (key_read(pub, &cp) != 1) {
 833                         key_free(pub);
 834                         continue;
 835                 }
 836                 if (key_compare(key, pub)) {
 837                         ret = 1;
 838                         key_free(pub);
 839                         break;
 840                 }
 841                 key_free(pub);
 842         }
 843         fclose(f);
 844         return ret;
 845 }
 846