ring/crypto/internal.h

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com). */

#ifndef OPENSSL_HEADER_CRYPTO_INTERNAL_H
#define OPENSSL_HEADER_CRYPTO_INTERNAL_H

#include <assert.h>

#if defined(__clang__) || defined(_MSC_VER)
#include <string.h>
#endif

#include <stddef.h>

#include <GFp/base.h>
#include <GFp/type_check.h>

#if defined(_MSC_VER)
#pragma warning(push, 3)
#include <intrin.h>
#pragma warning(pop)
#if !defined(__cplusplus)
#define alignas(x) __declspec(align(x))
#define alignof __alignof
#endif
#elif !defined(__clang__) && defined(__GNUC__) && __GNUC__ == 4 && \
      __GNUC_MINOR__ <= 6
#define alignas(x) __attribute__((aligned (x)))
#define alignof __alignof__
#else
#include <stdalign.h>
#endif

#if defined(__cplusplus)
extern "C" {
#endif


#if defined(OPENSSL_X86) || defined(OPENSSL_X86_64) || defined(OPENSSL_ARM) || \
    defined(OPENSSL_AARCH64) || defined(OPENSSL_PPC64LE)
/* OPENSSL_cpuid_setup initializes the platform-specific feature cache. */
void GFp_cpuid_setup(void);
#endif

#define OPENSSL_LITTLE_ENDIAN 1
#define OPENSSL_BIG_ENDIAN 2

#if defined(OPENSSL_X86_64) || defined(OPENSSL_X86) || \
    (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \
     __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#define OPENSSL_ENDIAN OPENSSL_LITTLE_ENDIAN
#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
      __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define OPENSSL_ENDIAN OPENSSL_BIG_ENDIAN
#else
#error "Cannot determine endianness"
#endif


#if defined(__GNUC__)
#define bswap_u32(x) __builtin_bswap32(x)
#define bswap_u64(x) __builtin_bswap64(x)
#elif defined(_MSC_VER)
#pragma intrinsic(_byteswap_ulong, _byteswap_uint64)
#define bswap_u32(x) _byteswap_ulong(x)
#define bswap_u64(x) _byteswap_uint64(x)
#endif


#if !defined(_MSC_VER) && defined(OPENSSL_64_BIT)
typedef __int128_t int128_t;
typedef __uint128_t uint128_t;
#endif


/* Constant-time utility functions.
 *
 * The following methods return a bitmask of all ones (0xff...f) for true and 0
 * for false. This is useful for choosing a value based on the result of a
 * conditional in constant time. */

/* constant_time_msb returns the given value with the MSB copied to all the
 * other bits. */
static inline unsigned int constant_time_msb_unsigned(unsigned int a) {
  return (unsigned int)((int)(a) >> (sizeof(int) * 8 - 1));
}

OPENSSL_COMPILE_ASSERT(sizeof(ptrdiff_t) == sizeof(size_t),
                       ptrdiff_t_and_size_t_are_different_sizes);

static inline size_t constant_time_msb_size_t(size_t a) {
  return (size_t)((ptrdiff_t)(a) >> (sizeof(ptrdiff_t) * 8 - 1));
}


/* constant_time_is_zero returns 0xff..f if a == 0 and 0 otherwise. */
static inline unsigned int constant_time_is_zero_unsigned(unsigned int a) {
  /* Here is an SMT-LIB verification of this formula:
   *
   * (define-fun is_zero ((a (_ BitVec 32))) (_ BitVec 32)
   *   (bvand (bvnot a) (bvsub a #x00000001))
   * )
   *
   * (declare-fun a () (_ BitVec 32))
   *
   * (assert (not (= (= #x00000001 (bvlshr (is_zero a) #x0000001f)) (= a #x00000000))))
   * (check-sat)
   * (get-model)
   */
  return constant_time_msb_unsigned(~a & (a - 1));
}

/* constant_time_is_zero_size_t is like |constant_time_is_zero_unsigned| but
 * operates on |size_t|. */
static inline size_t constant_time_is_zero_size_t(size_t a) {
  return constant_time_msb_size_t(~a & (a - 1));
}

static inline size_t constant_time_is_nonzero_size_t(size_t a) {
  return constant_time_is_zero_size_t(constant_time_is_zero_size_t(a));
}

/* constant_time_eq_int returns 0xff..f if a == b and 0 otherwise. */
static inline unsigned int constant_time_eq_int(int a, int b) {
  return constant_time_is_zero_unsigned((unsigned)(a) ^ (unsigned)(b));
}

/* constant_time_eq_size_t acts like |constant_time_eq_int| but operates on
 * |size_t|. */
static inline size_t constant_time_eq_size_t(size_t a, size_t b) {
  return constant_time_is_zero_size_t(a ^ b);
}

/* constant_time_select_size_t returns (mask & a) | (~mask & b). When |mask| is
 * all 1s or all 0s (as returned by the methods above), the select methods
 * return either |a| (if |mask| is nonzero) or |b| (if |mask| is zero). it is
 * derived from BoringSSL's |constant_time_select|. */
static inline size_t constant_time_select_size_t(size_t mask, size_t a,
                                                 size_t b) {
  return (mask & a) | (~mask & b);
}

/* from_be_u32_ptr returns the 32-bit big-endian-encoded value at |data|. */
static inline uint32_t from_be_u32_ptr(const uint8_t *data) {
#if defined(__clang__) || defined(_MSC_VER)
  /* XXX: Unlike GCC, Clang doesn't optimize compliant access to unaligned data
   * well. See https://llvm.org/bugs/show_bug.cgi?id=20605,
   * https://llvm.org/bugs/show_bug.cgi?id=17603,
   * http://blog.regehr.org/archives/702, and
   * http://blog.regehr.org/archives/1055. MSVC seems to have similar problems.
   */
  uint32_t value;
  memcpy(&value, data, sizeof(value));
#if OPENSSL_ENDIAN != OPENSSL_BIG_ENDIAN
  value = bswap_u32(value);
#endif
  return value;
#else
  return ((uint32_t)data[0] << 24) |
         ((uint32_t)data[1] << 16) |
         ((uint32_t)data[2] << 8) |
         ((uint32_t)data[3]);
#endif
}


/* from_be_u64_ptr returns the 64-bit big-endian-encoded value at |data|. */
static inline uint64_t from_be_u64_ptr(const uint8_t *data) {
#if defined(__clang__) || defined(_MSC_VER)
  /* XXX: Unlike GCC, Clang doesn't optimize compliant access to unaligned data
   * well. See https://llvm.org/bugs/show_bug.cgi?id=20605,
   * https://llvm.org/bugs/show_bug.cgi?id=17603,
   * http://blog.regehr.org/archives/702, and
   * http://blog.regehr.org/archives/1055. MSVC seems to have similar problems.
   */
  uint64_t value;
  memcpy(&value, data, sizeof(value));
#if OPENSSL_ENDIAN != OPENSSL_BIG_ENDIAN
  value = bswap_u64(value);
#endif
  return value;
#else
  return ((uint64_t)data[0] << 56) |
         ((uint64_t)data[1] << 48) |
         ((uint64_t)data[2] << 40) |
         ((uint64_t)data[3] << 32) |
         ((uint64_t)data[4] << 24) |
         ((uint64_t)data[5] << 16) |
         ((uint64_t)data[6] << 8) |
         ((uint64_t)data[7]);
#endif
}

/* to_be_u32_ptr writes the value |x| to the location |out| in big-endian
   order. */
static inline void to_be_u32_ptr(uint8_t *out, uint32_t value) {
#if defined(__clang__) || defined(_MSC_VER)
  /* XXX: Unlike GCC, Clang doesn't optimize compliant access to unaligned data
   * well. See https://llvm.org/bugs/show_bug.cgi?id=20605,
   * https://llvm.org/bugs/show_bug.cgi?id=17603,
   * http://blog.regehr.org/archives/702, and
   * http://blog.regehr.org/archives/1055. MSVC seems to have similar problems.
   */
#if  OPENSSL_ENDIAN != OPENSSL_BIG_ENDIAN
  value = bswap_u32(value);
#endif
  memcpy(out, &value, sizeof(value));
#else
  out[0] = (uint8_t)(value >> 24);
  out[1] = (uint8_t)(value >> 16);
  out[2] = (uint8_t)(value >> 8);
  out[3] = (uint8_t)value;
#endif
}

/* to_be_u64_ptr writes the value |value| to the location |out| in big-endian
   order. */
static inline void to_be_u64_ptr(uint8_t *out, uint64_t value) {
#if defined(__clang__) || defined(_MSC_VER)
  /* XXX: Unlike GCC, Clang doesn't optimize compliant access to unaligned data
   * well. See https://llvm.org/bugs/show_bug.cgi?id=20605,
   * https://llvm.org/bugs/show_bug.cgi?id=17603,
   * http://blog.regehr.org/archives/702, and
   * http://blog.regehr.org/archives/1055. MSVC seems to have similar problems.
   */
#if  OPENSSL_ENDIAN != OPENSSL_BIG_ENDIAN
  value = bswap_u64(value);
#endif
  memcpy(out, &value, sizeof(value));
#else
  out[0] = (uint8_t)(value >> 56);
  out[1] = (uint8_t)(value >> 48);
  out[2] = (uint8_t)(value >> 40);
  out[3] = (uint8_t)(value >> 32);
  out[4] = (uint8_t)(value >> 24);
  out[5] = (uint8_t)(value >> 16);
  out[6] = (uint8_t)(value >> 8);
  out[7] = (uint8_t)value;
#endif
}

/* from_be_u64 returns the native representation of the 64-bit
 * big-endian-encoded value |x|. */
static inline uint64_t from_be_u64(uint64_t x) {
#if OPENSSL_ENDIAN != OPENSSL_BIG_ENDIAN
  x = bswap_u64(x);
#endif
  return x;
}


#if defined(__cplusplus)
}  /* extern C */
#endif

#endif  /* OPENSSL_HEADER_CRYPTO_INTERNAL_H */