git / moonbite-core / src/support/cleanse.cpp · raw

// Copyright (c) 2009-2010 Satoshi Nakamoto// Copyright (c) 2009-2019 The Bitcoin Core developers// Distributed under the MIT software license, see the accompanying// file COPYING or http://www.opensource.org/licenses/mit-license.php.#include <support/cleanse.h>#include <cstring>#if defined(_MSC_VER)#include <Windows.h> // For SecureZeroMemory.#endifvoid memory_cleanse(void *ptr, size_t len){#if defined(_MSC_VER)    /* SecureZeroMemory is guaranteed not to be optimized out by MSVC. */    SecureZeroMemory(ptr, len);#else    std::memset(ptr, 0, len);    /* Memory barrier that scares the compiler away from optimizing out the memset.     *     * Quoting Adam Langley <agl@google.com> in commit ad1907fe73334d6c696c8539646c21b11178f20f     * in BoringSSL (ISC License):     *    As best as we can tell, this is sufficient to break any optimisations that     *    might try to eliminate "superfluous" memsets.     * This method is used in memzero_explicit() the Linux kernel, too. Its advantage is that it     * is pretty efficient because the compiler can still implement the memset() efficiently,     * just not remove it entirely. See "Dead Store Elimination (Still) Considered Harmful" by     * Yang et al. (USENIX Security 2017) for more background.     */    __asm__ __volatile__("" : : "r"(ptr) : "memory");#endif}