tor/src/lib/crypt_ops/crypto.c

/* Copyright (c) 2001, Matej Pfajfar.
 * Copyright (c) 2001-2004, Roger Dingledine.
 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 * Copyright (c) 2007-2018, The Tor Project, Inc. */
/* See LICENSE for licensing information */

/**
 * \file crypto.c
 * \brief Wrapper functions to present a consistent interface to
 * public-key and symmetric cryptography operations from OpenSSL and
 * other places.
 **/

#include "orconfig.h"

#ifdef _WIN32
#include <winsock2.h>
#include <windows.h>
#include <wincrypt.h>
/* Windows defines this; so does OpenSSL 0.9.8h and later. We don't actually
 * use either definition. */
#undef OCSP_RESPONSE
#endif /* defined(_WIN32) */

#define CRYPTO_PRIVATE
#include "lib/crypt_ops/compat_openssl.h"
#include "lib/crypt_ops/crypto.h"
#include "lib/crypt_ops/crypto_curve25519.h"
#include "lib/crypt_ops/crypto_digest.h"
#include "lib/crypt_ops/crypto_dh.h"
#include "lib/crypt_ops/crypto_ed25519.h"
#include "lib/crypt_ops/crypto_format.h"
#include "lib/crypt_ops/crypto_rand.h"
#include "lib/crypt_ops/crypto_rsa.h"
#include "lib/crypt_ops/crypto_util.h"

DISABLE_GCC_WARNING(redundant-decls)

#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <openssl/dh.h>
#include <openssl/conf.h>
#include <openssl/hmac.h>
#include <openssl/ssl.h>

ENABLE_GCC_WARNING(redundant-decls)

#if __GNUC__ && GCC_VERSION >= 402
#if GCC_VERSION >= 406
#pragma GCC diagnostic pop
#else
#pragma GCC diagnostic warning "-Wredundant-decls"
#endif
#endif /* __GNUC__ && GCC_VERSION >= 402 */

#ifdef HAVE_CTYPE_H
#include <ctype.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include "lib/log/log.h"
#include "lib/log/util_bug.h"
#include "lib/cc/torint.h"
#include "lib/crypt_ops/aes.h"
#include "lib/encoding/binascii.h"

#include "keccak-tiny/keccak-tiny.h"

#include "siphash.h"

#include <string.h>

/** Allocate and return a new symmetric cipher using the provided key and iv.
 * The key is <b>bits</b> bits long; the IV is CIPHER_IV_LEN bytes.  Both
 * must be provided. Key length must be 128, 192, or 256 */
crypto_cipher_t *
crypto_cipher_new_with_iv_and_bits(const uint8_t *key,
                                   const uint8_t *iv,
                                   int bits)
{
  tor_assert(key);
  tor_assert(iv);

  return aes_new_cipher((const uint8_t*)key, (const uint8_t*)iv, bits);
}

/** Allocate and return a new symmetric cipher using the provided key and iv.
 * The key is CIPHER_KEY_LEN bytes; the IV is CIPHER_IV_LEN bytes.  Both
 * must be provided.
 */
crypto_cipher_t *
crypto_cipher_new_with_iv(const char *key, const char *iv)
{
  return crypto_cipher_new_with_iv_and_bits((uint8_t*)key, (uint8_t*)iv,
                                            128);
}

/** Return a new crypto_cipher_t with the provided <b>key</b> and an IV of all
 * zero bytes and key length <b>bits</b>.  Key length must be 128, 192, or
 * 256. */
crypto_cipher_t *
crypto_cipher_new_with_bits(const char *key, int bits)
{
  char zeroiv[CIPHER_IV_LEN];
  memset(zeroiv, 0, sizeof(zeroiv));
  return crypto_cipher_new_with_iv_and_bits((uint8_t*)key, (uint8_t*)zeroiv,
                                            bits);
}

/** Return a new crypto_cipher_t with the provided <b>key</b> (of
 * CIPHER_KEY_LEN bytes) and an IV of all zero bytes.  */
crypto_cipher_t *
crypto_cipher_new(const char *key)
{
  return crypto_cipher_new_with_bits(key, 128);
}

/** Free a symmetric cipher.
 */
void
crypto_cipher_free_(crypto_cipher_t *env)
{
  if (!env)
    return;

  aes_cipher_free(env);
}

/** Copy <b>in</b> to the <b>outlen</b>-byte buffer <b>out</b>, adding spaces
 * every four characters. */
void
crypto_add_spaces_to_fp(char *out, size_t outlen, const char *in)
{
  int n = 0;
  char *end = out+outlen;
  tor_assert(outlen < SIZE_T_CEILING);

  while (*in && out<end) {
    *out++ = *in++;
    if (++n == 4 && *in && out<end) {
      n = 0;
      *out++ = ' ';
    }
  }
  tor_assert(out<end);
  *out = '\0';
}

/* symmetric crypto */

/** Encrypt <b>fromlen</b> bytes from <b>from</b> using the cipher
 * <b>env</b>; on success, store the result to <b>to</b> and return 0.
 * Does not check for failure.
 */
int
crypto_cipher_encrypt(crypto_cipher_t *env, char *to,
                      const char *from, size_t fromlen)
{
  tor_assert(env);
  tor_assert(env);
  tor_assert(from);
  tor_assert(fromlen);
  tor_assert(to);
  tor_assert(fromlen < SIZE_T_CEILING);

  memcpy(to, from, fromlen);
  aes_crypt_inplace(env, to, fromlen);
  return 0;
}

/** Decrypt <b>fromlen</b> bytes from <b>from</b> using the cipher
 * <b>env</b>; on success, store the result to <b>to</b> and return 0.
 * Does not check for failure.
 */
int
crypto_cipher_decrypt(crypto_cipher_t *env, char *to,
                      const char *from, size_t fromlen)
{
  tor_assert(env);
  tor_assert(from);
  tor_assert(to);
  tor_assert(fromlen < SIZE_T_CEILING);

  memcpy(to, from, fromlen);
  aes_crypt_inplace(env, to, fromlen);
  return 0;
}

/** Encrypt <b>len</b> bytes on <b>from</b> using the cipher in <b>env</b>;
 * on success. Does not check for failure.
 */
void
crypto_cipher_crypt_inplace(crypto_cipher_t *env, char *buf, size_t len)
{
  tor_assert(len < SIZE_T_CEILING);
  aes_crypt_inplace(env, buf, len);
}

/** Encrypt <b>fromlen</b> bytes (at least 1) from <b>from</b> with the key in
 * <b>key</b> to the buffer in <b>to</b> of length
 * <b>tolen</b>. <b>tolen</b> must be at least <b>fromlen</b> plus
 * CIPHER_IV_LEN bytes for the initialization vector. On success, return the
 * number of bytes written, on failure, return -1.
 */
int
crypto_cipher_encrypt_with_iv(const char *key,
                              char *to, size_t tolen,
                              const char *from, size_t fromlen)
{
  crypto_cipher_t *cipher;
  tor_assert(from);
  tor_assert(to);
  tor_assert(fromlen < INT_MAX);

  if (fromlen < 1)
    return -1;
  if (tolen < fromlen + CIPHER_IV_LEN)
    return -1;

  char iv[CIPHER_IV_LEN];
  crypto_rand(iv, sizeof(iv));
  cipher = crypto_cipher_new_with_iv(key, iv);

  memcpy(to, iv, CIPHER_IV_LEN);
  crypto_cipher_encrypt(cipher, to+CIPHER_IV_LEN, from, fromlen);
  crypto_cipher_free(cipher);
  memwipe(iv, 0, sizeof(iv));
  return (int)(fromlen + CIPHER_IV_LEN);
}

/** Decrypt <b>fromlen</b> bytes (at least 1+CIPHER_IV_LEN) from <b>from</b>
 * with the key in <b>key</b> to the buffer in <b>to</b> of length
 * <b>tolen</b>. <b>tolen</b> must be at least <b>fromlen</b> minus
 * CIPHER_IV_LEN bytes for the initialization vector. On success, return the
 * number of bytes written, on failure, return -1.
 */
int
crypto_cipher_decrypt_with_iv(const char *key,
                              char *to, size_t tolen,
                              const char *from, size_t fromlen)
{
  crypto_cipher_t *cipher;
  tor_assert(key);
  tor_assert(from);
  tor_assert(to);
  tor_assert(fromlen < INT_MAX);

  if (fromlen <= CIPHER_IV_LEN)
    return -1;
  if (tolen < fromlen - CIPHER_IV_LEN)
    return -1;

  cipher = crypto_cipher_new_with_iv(key, from);

  crypto_cipher_encrypt(cipher, to, from+CIPHER_IV_LEN, fromlen-CIPHER_IV_LEN);
  crypto_cipher_free(cipher);
  return (int)(fromlen - CIPHER_IV_LEN);
}