securemem.h

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#pragma once
 
#include <cstddef>
#include <promeki/core/namespace.h>
#include <promeki/core/platform.h>
#include <promeki/core/error.h>
 
#if defined(PROMEKI_PLATFORM_WINDOWS)
#       include <Windows.h>
#       include <memoryapi.h>
#elif defined(PROMEKI_PLATFORM_POSIX)
#       include <sys/mman.h>
#endif
 
PROMEKI_NAMESPACE_BEGIN
 
inline void secureZero(void *ptr, size_t size) {
        if(ptr == nullptr || size == 0) return;
#if defined(PROMEKI_PLATFORM_WINDOWS)
        SecureZeroMemory(ptr, size);
#elif defined(PROMEKI_LIBC_GLIBC) && \
      (PROMEKI_LIBC_GLIBC_VERSION_MAJOR > 2 || \
       (PROMEKI_LIBC_GLIBC_VERSION_MAJOR == 2 && PROMEKI_LIBC_GLIBC_VERSION_MINOR >= 25))
        explicit_bzero(ptr, size);
#elif defined(PROMEKI_PLATFORM_BSD)
        explicit_bzero(ptr, size);
#else
        volatile unsigned char *p = static_cast<volatile unsigned char *>(ptr);
        while(size--) *p++ = 0;
#endif
}
 
inline Error secureLock(void *ptr, size_t size) {
        if(ptr == nullptr || size == 0) return Error::Ok;
#if defined(PROMEKI_PLATFORM_WINDOWS)
        if(VirtualLock(ptr, size) == 0) return Error::syserr();
        return Error::Ok;
#elif defined(PROMEKI_PLATFORM_POSIX)
        if(mlock(ptr, size) != 0) return Error::syserr();
#       if defined(PROMEKI_PLATFORM_LINUX)
        madvise(ptr, size, MADV_DONTDUMP);
#       endif
        return Error::Ok;
#else
        return Error::NotSupported;
#endif
}
 
inline Error secureUnlock(void *ptr, size_t size) {
        if(ptr == nullptr || size == 0) return Error::Ok;
#if defined(PROMEKI_PLATFORM_WINDOWS)
        if(VirtualUnlock(ptr, size) == 0) return Error::syserr();
        return Error::Ok;
#elif defined(PROMEKI_PLATFORM_POSIX)
#       if defined(PROMEKI_PLATFORM_LINUX)
        madvise(ptr, size, MADV_DODUMP);
#       endif
        if(munlock(ptr, size) != 0) return Error::syserr();
        return Error::Ok;
#else
        return Error::NotSupported;
#endif
}
 
PROMEKI_NAMESPACE_END