Cred.h

/*
    SPDX-License-Identifier: MIT
    Copyright © 1991-2022 Amebis
    Copyright © 2016 GÉANT
*/
 
#pragma once
 
#include "Common.h"
#include <wincred.h>
#include <memory>
 
 
template<class _Traits, class _Ax>
static BOOL CredProtectA(_In_ BOOL fAsSelf, _In_count_(cchCredentials) LPCSTR pszCredentials, _In_ DWORD cchCredentials, _Inout_ std::basic_string<char, _Traits, _Ax> &sProtectedCredentials, _Out_ CRED_PROTECTION_TYPE *ProtectionType)
{
    char buf[WINSTD_STACK_BUFFER_BYTES/sizeof(char)];
    DWORD dwSize = _countof(buf);
 
    // Try with the stack buffer first.
    if (CredProtectA(fAsSelf, const_cast<LPSTR>(pszCredentials), cchCredentials, buf, &dwSize, ProtectionType)) {
        // Copy from stack.
        sProtectedCredentials.assign(buf, dwSize - 1);
        return TRUE;
    } else if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
        // Allocate on heap and retry.
        std::unique_ptr<char[]> buf(new char[dwSize]);
        if (CredProtectA(fAsSelf, const_cast<LPSTR>(pszCredentials), cchCredentials, buf.get(), &dwSize, ProtectionType)) {
            sProtectedCredentials.assign(buf.get(), dwSize - 1);
            return TRUE;
        }
    }
 
    return FALSE;
}
 
template<class _Traits, class _Ax>
static BOOL CredProtectW(_In_ BOOL fAsSelf, _In_count_(cchCredentials) LPCWSTR pszCredentials, _In_ DWORD cchCredentials, _Inout_ std::basic_string<wchar_t, _Traits, _Ax> &sProtectedCredentials, _Out_ CRED_PROTECTION_TYPE *ProtectionType)
{
    wchar_t buf[WINSTD_STACK_BUFFER_BYTES/sizeof(wchar_t)];
    DWORD dwSize = _countof(buf);
 
    // Try with the stack buffer first.
    if (CredProtectW(fAsSelf, const_cast<LPWSTR>(pszCredentials), cchCredentials, buf, &dwSize, ProtectionType)) {
        // Copy from stack.
        sProtectedCredentials.assign(buf, dwSize - 1);
        return TRUE;
    } else if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
        // Allocate on heap and retry.
        std::unique_ptr<wchar_t[]> buf(new wchar_t[dwSize]);
        if (CredProtectW(fAsSelf, const_cast<LPWSTR>(pszCredentials), cchCredentials, buf.get(), &dwSize, ProtectionType)) {
            sProtectedCredentials.assign(buf.get(), dwSize - 1);
            return TRUE;
        }
    }
 
    return FALSE;
}
 
template<class _Traits, class _Ax>
static BOOL CredUnprotectA(_In_ BOOL fAsSelf, _In_count_(cchCredentials) LPCSTR pszProtectedCredentials, _In_ DWORD cchCredentials, _Inout_ std::basic_string<char, _Traits, _Ax> &sCredentials)
{
    char buf[WINSTD_STACK_BUFFER_BYTES/sizeof(char)];
    DWORD dwSize = _countof(buf);
 
    // Try with the stack buffer first.
    if (CredUnprotectA(fAsSelf, const_cast<LPSTR>(pszProtectedCredentials), cchCredentials, buf, &dwSize)) {
        // Copy from stack.
        sCredentials.assign(buf, dwSize);
        return TRUE;
    } else if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
        // Allocate on heap and retry.
        std::unique_ptr<char[]> buf(new char[dwSize]);
        if (CredUnprotectA(fAsSelf, const_cast<LPSTR>(pszProtectedCredentials), cchCredentials, buf.get(), &dwSize)) {
            sCredentials.assign(buf.get(), dwSize);
            return TRUE;
        }
    }
 
    return FALSE;
}
 
template<class _Traits, class _Ax>
static BOOL CredUnprotectW(_In_ BOOL fAsSelf, _In_count_(cchCredentials) LPCWSTR pszProtectedCredentials, _In_ DWORD cchCredentials, _Inout_ std::basic_string<wchar_t, _Traits, _Ax> &sCredentials)
{
    wchar_t buf[WINSTD_STACK_BUFFER_BYTES/sizeof(wchar_t)];
    DWORD dwSize = _countof(buf);
 
    // Try with the stack buffer first.
    if (CredUnprotectW(fAsSelf, const_cast<LPWSTR>(pszProtectedCredentials), cchCredentials, buf, &dwSize)) {
        // Copy from stack.
        sCredentials.assign(buf, dwSize);
        return TRUE;
    } else if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
        // Allocate on heap and retry.
        std::unique_ptr<wchar_t[]> buf(new wchar_t[dwSize]);
        if (CredUnprotectW(fAsSelf, const_cast<LPWSTR>(pszProtectedCredentials), cchCredentials, buf.get(), &dwSize)) {
            sCredentials.assign(buf.get(), dwSize);
            return TRUE;
        }
    }
 
    return FALSE;
}
 
 
namespace winstd
{
 
    template <class _Ty> struct CredFree_delete
    {
        typedef CredFree_delete<_Ty> _Myt; 
 
        CredFree_delete() {}
 
        template <class _Ty2> CredFree_delete(const CredFree_delete<_Ty2>&) {}
 
        void operator()(_Ty *_Ptr) const
        {
            CredFree(_Ptr);
        }
    };
 
    template <class _Ty> struct CredFree_delete<_Ty[]>
    {
        typedef CredFree_delete<_Ty> _Myt; 
 
        CredFree_delete() {}
 
        void operator()(_Ty *_Ptr) const noexcept
        {
            CredFree(_Ptr);
        }
 
        template<class _Other>
        void operator()(_Other *) const
        {
            CredFree(_Ptr);
        }
    };
 
}
 
 
#pragma warning(suppress: 4505) // Don't warn on unused code
static BOOL CredEnumerate(_In_z_ LPCTSTR Filter, _Reserved_ DWORD Flags, _Out_ DWORD *Count, _Inout_ std::unique_ptr<PCREDENTIAL[], winstd::CredFree_delete<PCREDENTIAL[]> > &cCredentials) noexcept
{
    PCREDENTIAL *pCredentials;
    if (CredEnumerate(Filter, Flags, Count, &pCredentials)) {
        cCredentials.reset(pCredentials);
        return TRUE;
    }
 
    return FALSE;
}