boringssl/crypto/fipsmodule/delocate.h

/* Copyright (c) 2017, Google Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

#ifndef OPENSSL_HEADER_FIPSMODULE_DELOCATE_H
#define OPENSSL_HEADER_FIPSMODULE_DELOCATE_H

#include <openssl/base.h>

#include "../internal.h"


#if defined(BORINGSSL_FIPS)
#define DEFINE_BSS_GET(type, name)            \
  static type name __attribute__((used)); \
  type *name##_bss_get(void);
#else
#define DEFINE_BSS_GET(type, name) \
  static type name;            \
  static type *name##_bss_get(void) { return &name; }
#endif

/* DEFINE_METHOD_FUNCTION defines a function named |name| which returns a
 * method table of type const |type|*. In FIPS mode, to avoid rel.ro data, it
 * is split into a CRYPTO_once_t-guarded initializer in the module and
 * unhashed, non-module accessor functions to space reserved in the BSS. The
 * method table is initialized by a caller-supplied function which takes a
 * parameter named |out| of type |type|*. The caller should follow the macro
 * invocation with the body of this function:
 *
 *     DEFINE_METHOD_FUNCTION(EVP_MD, EVP_md4) {
 *       out->type = NID_md4;
 *       out->md_size = MD4_DIGEST_LENGTH;
 *       out->flags = 0;
 *       out->init = md4_init;
 *       out->update = md4_update;
 *       out->final = md4_final;
 *       out->block_size = 64;
 *       out->ctx_size = sizeof(MD4_CTX);
 *     }
 *
 * This mechanism does not use a static initializer because their execution
 * order is undefined. See FIPS.md for more details. */
#define DEFINE_METHOD_FUNCTION(type, name)                                    \
  DEFINE_BSS_GET(type, name##_storage)                                        \
  DEFINE_BSS_GET(CRYPTO_once_t, name##_once)                                  \
  static void name##_do_init(type *out);                                      \
  static void name##_init(void) { name##_do_init(name##_storage_bss_get()); } \
  const type *name(void) {                                                    \
    CRYPTO_once(name##_once_bss_get(), name##_init);                          \
    return name##_storage_bss_get();                                          \
  }                                                                           \
  static void name##_do_init(type *out)


#endif /* OPENSSL_HEADER_FIPSMODULE_DELOCATE_H */