src/tools/tor-gencert.c

   1 /* Copyright (c) 2007-2008 The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 #include "orconfig.h"
   5
   6 #include <stdio.h>
   7 #include <string.h>
   8
   9 #include <sys/types.h>
  10 #include <sys/stat.h>
  11 #include <fcntl.h>
  12 #include <unistd.h>
  13
  14 #include <openssl/evp.h>
  15 #include <openssl/pem.h>
  16 #include <openssl/objects.h>
  17 #include <openssl/obj_mac.h>
  18 #include <openssl/err.h>
  19
  20 #include <errno.h>
  21 #if 0
  22 #include <stdlib.h>
  23 #include <stdarg.h>
  24 #include <assert.h>
  25 #endif
  26
  27 #define CRYPTO_PRIVATE
  28
  29 #include "compat.h"
  30 #include "util.h"
  31 #include "log.h"
  32 #include "crypto.h"
  33 #include "address.h"
  34
  35 #define IDENTITY_KEY_BITS 3072
  36 #define SIGNING_KEY_BITS 1024
  37 #define DEFAULT_LIFETIME 12
  38
  39 /* These globals are set via command line options. */
  40 char *identity_key_file = NULL;
  41 char *signing_key_file = NULL;
  42 char *certificate_file = NULL;
  43 int reuse_signing_key = 0;
  44 int verbose = 0;
  45 int make_new_id = 0;
  46 int months_lifetime = DEFAULT_LIFETIME;
  47 int passphrase_fd = -1;
  48 char *address = NULL;
  49
  50 char *passphrase = NULL;
  51 size_t passphrase_len = 0;
  52
  53 EVP_PKEY *identity_key = NULL;
  54 EVP_PKEY *signing_key = NULL;
  55
  56 /** Write a usage message for tor-gencert to stderr. */
  57 static void
  58 show_help(void)
  59 {
  60   fprintf(stderr, "Syntax:\n"
  61           "tor-gencert [-h|--help] [-v] [-r|--reuse] [--create-identity-key]\n"
  62           "        [-i identity_key_file] [-s signing_key_file] "
  63           "[-c certificate_file]\n"
  64           "        [-m lifetime_in_months] [-a address:port] "
  65           "[--passphrase-fd <fd>]\n");
  66
  67 }
  68
  69 /* XXXX copied from crypto.c */
  70 static void
  71 crypto_log_errors(int severity, const char *doing)
  72 {
  73   unsigned int err;
  74   const char *msg, *lib, *func;
  75   while ((err = ERR_get_error()) != 0) {
  76     msg = (const char*)ERR_reason_error_string(err);
  77     lib = (const char*)ERR_lib_error_string(err);
  78     func = (const char*)ERR_func_error_string(err);
  79     if (!msg) msg = "(null)";
  80     if (!lib) lib = "(null)";
  81     if (!func) func = "(null)";
  82     if (doing) {
  83       log(severity, LD_CRYPTO, "crypto error while %s: %s (in %s:%s)",
  84           doing, msg, lib, func);
  85     } else {
  86       log(severity, LD_CRYPTO, "crypto error: %s (in %s:%s)", msg, lib, func);
  87     }
  88   }
  89 }
  90
  91 /** Read the passphrase from the passphrase fd. */
  92 static int
  93 load_passphrase(void)
  94 {
  95   char *cp;
  96   char buf[1024]; /* "Ought to be enough for anybody." */
  97   int n = read_all(passphrase_fd, buf, sizeof(buf), 0);
  98   if (n < 0) {
  99     log_err(LD_GENERAL, "Couldn't read from passphrase fd: %s",
 100             strerror(errno));
 101     return -1;
 102   }
 103   cp = memchr(buf, '\n', n);
 104   passphrase_len = cp-buf;
 105   passphrase = tor_strndup(buf, passphrase_len);
 106   memset(buf, 0, sizeof(buf));
 107   return 0;
 108 }
 109
 110 static void
 111 clear_passphrase(void)
 112 {
 113   if (passphrase) {
 114     memset(passphrase, 0, passphrase_len);
 115     tor_free(passphrase);
 116   }
 117 }
 118
 119 /** Read the command line options from <b>argc</b> and <b>argv</b>,
 120  * setting global option vars as needed.
 121  */
 122 static int
 123 parse_commandline(int argc, char **argv)
 124 {
 125   int i;
 126   log_severity_list_t s;
 127   for (i = 1; i < argc; ++i) {
 128     if (!strcmp(argv[i], "--help") || !strcmp(argv[i], "-h")) {
 129       show_help();
 130       return 1;
 131     } else if (!strcmp(argv[i], "-i")) {
 132       if (i+1>=argc) {
 133         fprintf(stderr, "No argument to -i\n");
 134         return 1;
 135       }
 136       identity_key_file = tor_strdup(argv[++i]);
 137     } else if (!strcmp(argv[i], "-s")) {
 138       if (i+1>=argc) {
 139         fprintf(stderr, "No argument to -s\n");
 140         return 1;
 141       }
 142       signing_key_file = tor_strdup(argv[++i]);
 143     } else if (!strcmp(argv[i], "-c")) {
 144       if (i+1>=argc) {
 145         fprintf(stderr, "No argument to -c\n");
 146         return 1;
 147       }
 148       certificate_file = tor_strdup(argv[++i]);
 149     } else if (!strcmp(argv[i], "-m")) {
 150       if (i+1>=argc) {
 151         fprintf(stderr, "No argument to -m\n");
 152         return 1;
 153       }
 154       months_lifetime = atoi(argv[++i]);
 155       if (months_lifetime > 24 || months_lifetime < 0) {
 156         fprintf(stderr, "Lifetime (in months) was out of range.");
 157         return 1;
 158       }
 159     } else if (!strcmp(argv[i], "-r") || !strcmp(argv[i], "--reuse")) {
 160       reuse_signing_key = 1;
 161     } else if (!strcmp(argv[i], "-v")) {
 162       verbose = 1;
 163     } else if (!strcmp(argv[i], "-a")) {
 164       uint32_t addr;
 165       uint16_t port;
 166       char b[INET_NTOA_BUF_LEN];
 167       struct in_addr in;
 168       if (i+1>=argc) {
 169         fprintf(stderr, "No argument to -a\n");
 170         return 1;
 171       }
 172       if (parse_addr_port(LOG_ERR, argv[++i], NULL, &addr, &port)<0)
 173         return 1;
 174       in.s_addr = htonl(addr);
 175       tor_inet_ntoa(&in, b, sizeof(b));
 176       address = tor_malloc(INET_NTOA_BUF_LEN+32);
 177       tor_snprintf(address, INET_NTOA_BUF_LEN+32, "%s:%d", b, (int)port);
 178     } else if (!strcmp(argv[i], "--create-identity-key")) {
 179       make_new_id = 1;
 180     } else if (!strcmp(argv[i], "--passphrase-fd")) {
 181       if (i+1>=argc) {
 182         fprintf(stderr, "No argument to --passphrase-fd\n");
 183         return 1;
 184       }
 185       passphrase_fd = atoi(argv[++i]);
 186     } else {
 187       fprintf(stderr, "Unrecognized option %s\n", argv[i]);
 188       return 1;
 189     }
 190   }
 191
 192   memset(&s, 0, sizeof(s));
 193   if (verbose)
 194     set_log_severity_config(LOG_DEBUG, LOG_ERR, &s);
 195   else
 196     set_log_severity_config(LOG_WARN, LOG_ERR, &s);
 197   add_stream_log(&s, "<stderr>", fileno(stderr));
 198
 199   if (!identity_key_file) {
 200     identity_key_file = tor_strdup("./authority_identity_key");
 201     log_info(LD_GENERAL, "No identity key file given; defaulting to %s",
 202              identity_key_file);
 203   }
 204   if (!signing_key_file) {
 205     signing_key_file = tor_strdup("./authority_signing_key");
 206     log_info(LD_GENERAL, "No signing key file given; defaulting to %s",
 207              signing_key_file);
 208   }
 209   if (!certificate_file) {
 210     certificate_file = tor_strdup("./authority_certificate");
 211     log_info(LD_GENERAL, "No signing key file given; defaulting to %s",
 212              certificate_file);
 213   }
 214   if (passphrase_fd >= 0) {
 215     if (load_passphrase()<0)
 216       return 1;
 217   }
 218   return 0;
 219 }
 220
 221 /** Try to read the identity key from <b>identity_key_file</b>.  If no such
 222  * file exists and create_identity_key is set, make a new identity key and
 223  * store it.  Return 0 on success, nonzero on failure.
 224  */
 225 static int
 226 load_identity_key(void)
 227 {
 228   file_status_t status = file_status(identity_key_file);
 229   FILE *f;
 230
 231   if (make_new_id) {
 232     open_file_t *open_file = NULL;
 233     RSA *key;
 234     if (status != FN_NOENT) {
 235       log_err(LD_GENERAL, "--create-identity-key was specified, but %s "
 236               "already exists.", identity_key_file);
 237       return 1;
 238     }
 239     log_notice(LD_GENERAL, "Generating %d-bit RSA identity key.",
 240                IDENTITY_KEY_BITS);
 241     if (!(key = RSA_generate_key(IDENTITY_KEY_BITS, 65537, NULL, NULL))) {
 242       log_err(LD_GENERAL, "Couldn't generate identity key.");
 243       crypto_log_errors(LOG_ERR, "Generating identity key");
 244       return 1;
 245     }
 246     identity_key = EVP_PKEY_new();
 247     if (!(EVP_PKEY_assign_RSA(identity_key, key))) {
 248       log_err(LD_GENERAL, "Couldn't assign identity key.");
 249       return 1;
 250     }
 251
 252     if (!(f = start_writing_to_stdio_file(identity_key_file,
 253                                           OPEN_FLAGS_REPLACE, 0400,
 254                                           &open_file)))
 255       return 1;
 256
 257     /* Write the key to the file.  If passphrase is not set, takes it from
 258      * the terminal. */
 259     if (!PEM_write_PKCS8PrivateKey_nid(f, identity_key,
 260                                        NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
 261                                        passphrase, (int)passphrase_len,
 262                                        NULL, NULL)) {
 263       log_err(LD_GENERAL, "Couldn't write identity key to %s",
 264               identity_key_file);
 265       crypto_log_errors(LOG_ERR, "Writing identity key");
 266       abort_writing_to_file(open_file);
 267       return 1;
 268     }
 269     finish_writing_to_file(open_file);
 270   } else {
 271     if (status != FN_FILE) {
 272       log_err(LD_GENERAL,
 273               "No identity key found in %s.  To specify a location "
 274               "for an identity key, use -i.  To generate a new identity key, "
 275               "use --create-identity-key.", identity_key_file);
 276       return 1;
 277     }
 278
 279     if (!(f = fopen(identity_key_file, "r"))) {
 280       log_err(LD_GENERAL, "Couldn't open %s for reading: %s",
 281               identity_key_file, strerror(errno));
 282       return 1;
 283     }
 284
 285     /* Read the key.  If passphrase is not set, takes it from the terminal. */
 286     identity_key = PEM_read_PrivateKey(f, NULL, NULL, passphrase);
 287     if (!identity_key) {
 288       log_err(LD_GENERAL, "Couldn't read identity key from %s",
 289               identity_key_file);
 290       return 1;
 291     }
 292     fclose(f);
 293   }
 294   return 0;
 295 }
 296
 297 /** Load a saved signing key from disk.  Return 0 on success, nonzero on
 298  * failure. */
 299 static int
 300 load_signing_key(void)
 301 {
 302   FILE *f;
 303   if (!(f = fopen(signing_key_file, "r"))) {
 304     log_err(LD_GENERAL, "Couldn't open %s for reading: %s",
 305             signing_key_file, strerror(errno));
 306     return 1;
 307   }
 308   if (!(signing_key = PEM_read_PrivateKey(f, NULL, NULL, NULL))) {
 309     log_err(LD_GENERAL, "Couldn't read siging key from %s", signing_key_file);
 310     return 1;
 311   }
 312   fclose(f);
 313   return 0;
 314 }
 315
 316 /** Generate a new signing key and write it to disk.  Return 0 on success,
 317  * nonzero on failure. */
 318 static int
 319 generate_signing_key(void)
 320 {
 321   open_file_t *open_file;
 322   FILE *f;
 323   RSA *key;
 324   log_notice(LD_GENERAL, "Generating %d-bit RSA signing key.",
 325              SIGNING_KEY_BITS);
 326   if (!(key = RSA_generate_key(SIGNING_KEY_BITS, 65537, NULL, NULL))) {
 327     log_err(LD_GENERAL, "Couldn't generate signing key.");
 328     crypto_log_errors(LOG_ERR, "Generating signing key");
 329     return 1;
 330   }
 331   signing_key = EVP_PKEY_new();
 332   if (!(EVP_PKEY_assign_RSA(signing_key, key))) {
 333     log_err(LD_GENERAL, "Couldn't assign signing key.");
 334     return 1;
 335   }
 336
 337   if (!(f = start_writing_to_stdio_file(signing_key_file,
 338                                         OPEN_FLAGS_REPLACE, 0600,
 339                                         &open_file)))
 340     return 1;
 341
 342   /* Write signing key with no encryption. */
 343   if (!PEM_write_RSAPrivateKey(f, key, NULL, NULL, 0, NULL, NULL)) {
 344     crypto_log_errors(LOG_WARN, "writing signing key");
 345     abort_writing_to_file(open_file);
 346     return 1;
 347   }
 348
 349   finish_writing_to_file(open_file);
 350
 351   return 0;
 352 }
 353
 354 /** Encode <b>key</b> in the format used in directory documents; return
 355  * a newly allocated string holding the result or NULL on failure. */
 356 static char *
 357 key_to_string(EVP_PKEY *key)
 358 {
 359   BUF_MEM *buf;
 360   BIO *b;
 361   RSA *rsa = EVP_PKEY_get1_RSA(key);
 362   char *result;
 363   if (!rsa)
 364     return NULL;
 365
 366   b = BIO_new(BIO_s_mem());
 367   if (!PEM_write_bio_RSAPublicKey(b, rsa)) {
 368     crypto_log_errors(LOG_WARN, "writing public key to string");
 369     return NULL;
 370   }
 371
 372   BIO_get_mem_ptr(b, &buf);
 373   (void) BIO_set_close(b, BIO_NOCLOSE);
 374   BIO_free(b);
 375   result = tor_malloc(buf->length + 1);
 376   memcpy(result, buf->data, buf->length);
 377   result[buf->length] = 0;
 378   BUF_MEM_free(buf);
 379
 380   return result;
 381 }
 382
 383 /** Set <b>out</b> to the hex-encoded fingerprint of <b>pkey</b>. */
 384 static int
 385 get_fingerprint(EVP_PKEY *pkey, char *out)
 386 {
 387   int r = 1;
 388   crypto_pk_env_t *pk = _crypto_new_pk_env_rsa(EVP_PKEY_get1_RSA(pkey));
 389   if (pk) {
 390     r = crypto_pk_get_fingerprint(pk, out, 0);
 391     crypto_free_pk_env(pk);
 392   }
 393   return r;
 394 }
 395
 396
 397 /** Set <b>out</b> to the hex-encoded fingerprint of <b>pkey</b>. */
 398 static int
 399 get_digest(EVP_PKEY *pkey, char *out)
 400 {
 401   int r = 1;
 402   crypto_pk_env_t *pk = _crypto_new_pk_env_rsa(EVP_PKEY_get1_RSA(pkey));
 403   if (pk) {
 404     r = crypto_pk_get_digest(pk, out);
 405     crypto_free_pk_env(pk);
 406   }
 407   return r;
 408 }
 409
 410 /** Generate a new certificate for our loaded or generated keys, and write it
 411  * to disk.  Return 0 on success, nonzero on failure. */
 412 static int
 413 generate_certificate(void)
 414 {
 415   char buf[8192];
 416   time_t now = time(NULL);
 417   struct tm tm;
 418   char published[ISO_TIME_LEN+1];
 419   char expires[ISO_TIME_LEN+1];
 420   char id_digest[DIGEST_LEN];
 421   char fingerprint[FINGERPRINT_LEN+1];
 422   char *ident = key_to_string(identity_key);
 423   char *signing = key_to_string(signing_key);
 424   FILE *f;
 425   size_t signed_len;
 426   char digest[DIGEST_LEN];
 427   char signature[1024]; /* handles up to 8192-bit keys. */
 428   int r;
 429
 430   get_fingerprint(identity_key, fingerprint);
 431   get_digest(identity_key, id_digest);
 432
 433   tor_localtime_r(&now, &tm);
 434   tm.tm_mon += months_lifetime;
 435
 436   format_iso_time(published, now);
 437   format_iso_time(expires, mktime(&tm));
 438
 439   tor_snprintf(buf, sizeof(buf),
 440                "dir-key-certificate-version 3"
 441                "%s%s"
 442                "\nfingerprint %s\n"
 443                "dir-key-published %s\n"
 444                "dir-key-expires %s\n"
 445                "dir-identity-key\n%s"
 446                "dir-signing-key\n%s"
 447                "dir-key-crosscert\n"
 448                "-----BEGIN ID SIGNATURE-----\n",
 449                address?"\ndir-address ":"", address?address:"",
 450                fingerprint, published, expires, ident, signing
 451                );
 452   tor_free(ident);
 453   tor_free(signing);
 454
 455   /* Append a cross-certification */
 456   r = RSA_private_encrypt(DIGEST_LEN, (unsigned char*)id_digest,
 457                           (unsigned char*)signature,
 458                           EVP_PKEY_get1_RSA(signing_key),
 459                           RSA_PKCS1_PADDING);
 460   signed_len = strlen(buf);
 461   base64_encode(buf+signed_len, sizeof(buf)-signed_len, signature, r);
 462
 463   strlcat(buf,
 464           "-----END ID SIGNATURE-----\n"
 465           "dir-key-certification\n", sizeof(buf));
 466
 467   signed_len = strlen(buf);
 468   SHA1((const unsigned char*)buf,signed_len,(unsigned char*)digest);
 469
 470   r = RSA_private_encrypt(DIGEST_LEN, (unsigned char*)digest,
 471                           (unsigned char*)signature,
 472                           EVP_PKEY_get1_RSA(identity_key),
 473                           RSA_PKCS1_PADDING);
 474   strlcat(buf, "-----BEGIN SIGNATURE-----\n", sizeof(buf));
 475   signed_len = strlen(buf);
 476   base64_encode(buf+signed_len, sizeof(buf)-signed_len, signature, r);
 477   strlcat(buf, "-----END SIGNATURE-----\n", sizeof(buf));
 478
 479   if (!(f = fopen(certificate_file, "w"))) {
 480     log_err(LD_GENERAL, "Couldn't open %s for writing: %s",
 481             certificate_file, strerror(errno));
 482     return 1;
 483   }
 484
 485   fputs(buf, f);
 486   fclose(f);
 487   return 0;
 488 }
 489
 490
 491 /** Entry point to tor-gencert */
 492 int
 493 main(int argc, char **argv)
 494 {
 495   int r = 1;
 496   init_logging();
 497
 498   /* Don't bother using acceleration. */
 499   if (crypto_global_init(0)) {
 500     fprintf(stderr, "Couldn't initialize crypto library.\n");
 501     return 1;
 502   }
 503   if (crypto_seed_rng(1)) {
 504     fprintf(stderr, "Couldn't seed RNG.\n");
 505     goto done;
 506   }
 507   /* Make sure that files are made private. */
 508   umask(0077);
 509
 510   if (parse_commandline(argc, argv))
 511     goto done;
 512   if (load_identity_key())
 513     goto done;
 514   if (reuse_signing_key) {
 515     if (load_signing_key())
 516       goto done;
 517   } else {
 518     if (generate_signing_key())
 519       goto done;
 520   }
 521   if (generate_certificate())
 522     goto done;
 523
 524   r = 0;
 525  done:
 526   clear_passphrase();
 527   if (identity_key)
 528     EVP_PKEY_free(identity_key);
 529   if (signing_key)
 530     EVP_PKEY_free(signing_key);
 531   tor_free(address);
 532
 533   crypto_global_cleanup();
 534   return r;
 535 }
 536