r12596@catbus: nickm | 2007-04-30 18:42:44 -0400

New tool to generate key certificates as in proposal 103. needs cleanup


svn:r10075

ChangeLog

@@ -16,6 +16,8 @@ Changes in version 0.2.0.1-alpha - 2007-??-??
     - Add an HSAuthorityRecordStats option that hidden service authorities
       can use to track statistics of overall hidden service usage without
       logging information that would be very useful to an attacker.
+    - Start work implementing proposal 103: Add a standalone tool to
+      generate key certificates.
 
   o Security fixes:
     - Directory authorities now call routers stable if they have an

src/tools/Makefile.am

@@ -1,6 +1,10 @@
-bin_PROGRAMS = tor-resolve
+bin_PROGRAMS = tor-resolve tor-gencert
 
 tor_resolve_SOURCES = tor-resolve.c
-
+tor_resolve_LDFLAGS = @TOR_LDFLAGS_libevent@ -levent
 tor_resolve_LDADD = ../common/libor.a
 
+tor_gencert_SOURCES = tor-gencert.c
+tor_gencert_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
+        @TOR_LDFLAGS_libevent@ -lz -lcrypto -levent
+tor_gencert_LDADD = ../common/libor.a ../common/libor-crypto.a

src/tools/tor-gencert.c

@@ -0,0 +1,356 @@
+/* Copyright 2007 Roger Dingledine, Nick Mathewson */
+/* See LICENSE for licensing information */
+/* $Id: /tor/trunk/src/tools/tor-resolve.c 12481 2007-04-21T17:27:19.371353Z nickm  $ */
+
+#include "orconfig.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+#include <openssl/objects.h>
+#include <openssl/obj_mac.h>
+#include <openssl/err.h>
+
+#include <errno.h>
+#if 0
+#include <stdlib.h>
+#include <stdarg.h>
+#include <assert.h>
+#endif
+
+#define CRYPTO_PRIVATE
+
+#include "../common/compat.h"
+#include "../common/util.h"
+#include "../common/log.h"
+#include "../common/crypto.h"
+
+#define IDENTITY_KEY_BITS 3072
+#define SIGNING_KEY_BITS 1024
+
+char *identity_key_file = NULL;
+char *signing_key_file = NULL;
+char *certificate_file = NULL;
+int verbose = 0;
+int make_new_id = 0;
+
+EVP_PKEY *identity_key = NULL;
+EVP_PKEY *signing_key = NULL;
+
+/* DOCDOC */
+static void
+show_help(void)
+{
+  fprintf(stderr, "Syntax:\n"
+          "tor-gencert [-h|--help] [-v] [--create-identity-key] "
+          "[-i identity_key_file]\n"
+          "            [-s signing_key_file] [-c certificate_file]\n");
+}
+
+/* XXXX copied from crypto.c */
+static void
+crypto_log_errors(int severity, const char *doing)
+{
+  unsigned int err;
+  const char *msg, *lib, *func;
+  while ((err = ERR_get_error()) != 0) {
+    msg = (const char*)ERR_reason_error_string(err);
+    lib = (const char*)ERR_lib_error_string(err);
+    func = (const char*)ERR_func_error_string(err);
+    if (!msg) msg = "(null)";
+    if (!lib) lib = "(null)";
+    if (!func) func = "(null)";
+    if (doing) {
+      log(severity, LD_CRYPTO, "crypto error while %s: %s (in %s:%s)",
+          doing, msg, lib, func);
+    } else {
+      log(severity, LD_CRYPTO, "crypto error: %s (in %s:%s)", msg, lib, func);
+    }
+  }
+}
+
+/** DOCDOC */
+static int
+parse_commandline(int argc, char **argv)
+{
+  int i;
+  for (i = 1; i < argc; ++i) {
+    if (!strcmp(argv[i], "--help") || !strcmp(argv[i], "-h")) {
+      show_help();
+      return 1;
+    } else if (!strcmp(argv[i], "-i")) {
+      if (i+1>=argc) {
+        fprintf(stderr, "No argument to -i\n");
+        return 1;
+      }
+      identity_key_file = tor_strdup(argv[++i]);
+    } else if (!strcmp(argv[i], "-c")) {
+      if (i+1>=argc) {
+        fprintf(stderr, "No argument to -c\n");
+        return 1;
+      }
+      certificate_file = tor_strdup(argv[++i]);
+    } else if (!strcmp(argv[i], "-v")) {
+      verbose = 1;
+    } else if (!strcmp(argv[i], "--create-identity-key")) {
+      make_new_id = 1;
+    } else {
+      fprintf(stderr, "Unrecognized option %s\n", argv[i]);
+      return 1;
+    }
+  }
+
+  if (verbose) {
+    add_stream_log(LOG_INFO, LOG_ERR, "<stderr>", stderr);
+  } else {
+    add_stream_log(LOG_NOTICE, LOG_ERR, "<stderr>", stderr);
+  }
+
+  if (!identity_key_file) {
+    identity_key_file = tor_strdup("./authority_identity_key");
+    log_info(LD_GENERAL, "No identity key file given; defaulting to %s",
+             identity_key_file);
+  }
+  if (!signing_key_file) {
+    signing_key_file = tor_strdup("./authority_signing_key");
+    log_info(LD_GENERAL, "No signing key file given; defaulting to %s",
+             signing_key_file);
+  }
+  if (!certificate_file) {
+    certificate_file = tor_strdup("./authority_certificate");
+    log_info(LD_GENERAL, "No signing key file given; defaulting to %s",
+             signing_key_file);
+  }
+  return 0;
+}
+
+/** DOCDOC */
+static int
+load_identity_key(void)
+{
+  file_status_t status = file_status(identity_key_file);
+  FILE *f;
+
+  if (make_new_id) {
+    RSA *key;
+    if (status != FN_NOENT) {
+      log_err(LD_GENERAL, "--create-identity-key was specified, but %s "
+              "already exists.", identity_key_file);
+      return 1;
+    }
+    log_notice(LD_GENERAL, "Generating %d-bit RSA identity key.",
+               IDENTITY_KEY_BITS);
+    if (!(key = RSA_generate_key(IDENTITY_KEY_BITS, 65537, NULL, NULL))) {
+      log_err(LD_GENERAL, "Couldn't generate identity key.");
+      crypto_log_errors(LOG_ERR, "Generating identity key");
+      return 1;
+    }
+    identity_key = EVP_PKEY_new();
+    if (!(EVP_PKEY_assign_RSA(identity_key, key))) {
+      log_err(LD_GENERAL, "Couldn't assign identity key.");
+      return 1;
+    }
+
+    if (!(f = fopen(identity_key_file, "w"))) {
+      log_err(LD_GENERAL, "Couldn't open %s for writing: %s",
+              identity_key_file, strerror(errno));
+      return 1;
+    }
+
+    if (!PEM_write_PKCS8PrivateKey_nid(f, identity_key,
+                                       NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
+                                       NULL, 0, /* no password here. */
+                                       NULL, NULL)) {
+      log_err(LD_GENERAL, "Couldn't write identity key to %s",
+              identity_key_file);
+      crypto_log_errors(LOG_ERR, "Writing identity key");
+      return 1;
+    }
+    fclose(f);
+  } else {
+    if (status != FN_FILE) {
+      log_err(LD_GENERAL,
+              "No identity key found in %s.  To specify a location "
+              "for an identity key, use -i.  To generate a new identity key, "
+              "use --create-identity-key.", identity_key_file);
+      return 1;
+    }
+
+    if (!(f = fopen(identity_key_file, "r"))) {
+      log_err(LD_GENERAL, "Couldn't open %s for reading: %s",
+              identity_key_file, strerror(errno));
+      return 1;
+    }
+
+    identity_key = PEM_read_PrivateKey(f, NULL, NULL, NULL);
+    if (!identity_key) {
+      log_err(LD_GENERAL, "Couldn't read identity key from %s",
+              identity_key_file);
+      return 1;
+    }
+    fclose(f);
+  }
+  return 0;
+}
+
+/** DOCDOC */
+static int
+generate_signing_key(void)
+{
+  FILE *f;
+  RSA *key;
+  log_notice(LD_GENERAL, "Generating %d-bit RSA signing key.",
+             SIGNING_KEY_BITS);
+  if (!(key = RSA_generate_key(SIGNING_KEY_BITS, 65537, NULL, NULL))) {
+    log_err(LD_GENERAL, "Couldn't generate signing key.");
+    crypto_log_errors(LOG_ERR, "Generating signing key");
+    return 1;
+  }
+  signing_key = EVP_PKEY_new();
+  if (!(EVP_PKEY_assign_RSA(signing_key, key))) {
+    log_err(LD_GENERAL, "Couldn't assign signing key.");
+    return 1;
+  }
+
+  if (!(f = fopen(signing_key_file, "w"))) {
+    log_err(LD_GENERAL, "Couldn't open %s for reading: %s",
+            signing_key_file, strerror(errno));
+    return 1;
+  }
+
+  /* Write signing key with no encryption. */
+  if (!PEM_write_RSAPrivateKey(f, key, NULL, NULL, 0, NULL, NULL)) {
+    crypto_log_errors(LOG_WARN, "writing signing key");
+    return 1;
+  }
+
+  fclose(f);
+
+  return 0;
+}
+
+static char *
+key_to_string(EVP_PKEY *key)
+{
+  BUF_MEM *buf;
+  BIO *b;
+  RSA *rsa = EVP_PKEY_get1_RSA(key);
+  char *result;
+  if (!rsa)
+    return NULL;
+
+  b = BIO_new(BIO_s_mem());
+  if (!PEM_write_bio_RSAPublicKey(b, rsa)) {
+    crypto_log_errors(LOG_WARN, "writing public key to string");
+    return NULL;
+  }
+
+  BIO_get_mem_ptr(b, &buf);
+  (void) BIO_set_close(b, BIO_NOCLOSE);
+  BIO_free(b);
+  result = tor_malloc(buf->length + 1);
+  memcpy(result, buf->data, buf->length);
+  result[buf->length] = 0;
+  BUF_MEM_free(buf);
+
+  return result;
+}
+
+static int
+get_fingerprint(EVP_PKEY *pkey, char *out)
+{
+  int r = 1;
+  crypto_pk_env_t *pk = _crypto_new_pk_env_rsa(EVP_PKEY_get1_RSA(pkey));
+  if (pk) {
+    r = crypto_pk_get_fingerprint(pk, out, 0);
+    crypto_free_pk_env(pk);
+  }
+  return r;
+}
+
+static int
+generate_certificate(void)
+{
+  char buf[8192];
+  time_t now = time(NULL);
+  char published[ISO_TIME_LEN+1];
+  char fingerprint[FINGERPRINT_LEN+1];
+  char *ident = key_to_string(identity_key);
+  char *signing = key_to_string(signing_key);
+  FILE *f;
+  size_t signed_len;
+  char digest[DIGEST_LEN];
+  char signature[1024]; /* handles up to 8192-bit keys. */
+  int r;
+
+  get_fingerprint(identity_key, fingerprint);
+  format_iso_time(published, now);
+
+  tor_snprintf(buf, sizeof(buf),
+               "dir-key-certificate-version 3\n"
+               "fingerprint %s\n"
+               "dir-key-published %s\n"
+               "dir-identity-key\n%s"
+               "dir-signing-key\n%s"
+               "dir-key-certification\n",
+               fingerprint, published, ident, signing);
+  signed_len = strlen(buf);
+  SHA1((const unsigned char*)buf,signed_len,(unsigned char*)digest);
+
+  r = RSA_private_encrypt(DIGEST_LEN, (unsigned char*)digest,
+                          (unsigned char*)signature,
+                          EVP_PKEY_get1_RSA(identity_key),
+                          RSA_PKCS1_PADDING);
+  strlcat(buf, "-----BEGIN_SIGNATURE-----\n", sizeof(buf));
+  signed_len = strlen(buf);
+  base64_encode(buf+signed_len, sizeof(buf)-signed_len, signature, r);
+  strlcat(buf, "-----END_SIGNATURE-----\n", sizeof(buf));
+
+  if (!(f = fopen(certificate_file, "w"))) {
+    log_err(LD_GENERAL, "Couldn't open %s for writing: %s",
+            certificate_file, strerror(errno));
+    return 1;
+  }
+
+  fputs(buf, f);
+  fclose(f);
+  return 0;
+}
+
+
+/** Entry point to tor-gencert */
+int
+main(int argc, char **argv)
+{
+  int r = 1;
+  /* Don't bother using acceleration. */
+  if (crypto_global_init(0)) {
+    fprintf(stderr, "Couldn't initialize crypto library.\n");
+    return 1;
+  }
+  if (crypto_seed_rng()) {
+    fprintf(stderr, "Couldn't seed RNG.\n");
+    goto done;
+  }
+  if (parse_commandline(argc, argv))
+    goto done;
+  if (load_identity_key())
+    goto done;
+  if (generate_signing_key())
+    goto done;
+  if (generate_certificate())
+    goto done;
+
+  r = 0;
+ done:
+  if (identity_key)
+    EVP_PKEY_free(identity_key);
+  if (signing_key)
+    EVP_PKEY_free(signing_key);
+
+  crypto_global_cleanup();
+  return r;
+}
+