Return 从本机代码到托管损坏了返回的对象

Question

我正在尝试使用 C++/CLI 和 yubico 的 libu2f-host(https://github.com/Yubico/libu2f-host) 在我的 WPF 程序中构建 U2F 身份验证的实现我的 C++/CLI dll 中有一个完全原生的函数，它调用适当的 libu2f 函数，然后它 return 是指向 u2f_reply（我自己的 class）的指针，其中包含响应和错误代码。但是，当 dll 的托管部分接收到此对象时，响应代码仍然正确，但响应字符串似乎已完全损坏。

我尝试立即 returning char 指针，然后使用 marshal 将其转换为托管字符串，我尝试使用标准 C# 字符串。我尝试使用 memcpy 将响应复制到 reply->response 但没有成功。

Managed_U2F_Reply^ Utilities::AuthenticateU2F(System::String^ challenge)
{
    IntPtr ptrToChallenge = System::Runtime::InteropServices::Marshal::StringToHGlobalAnsi(challenge);
    u2f_reply* reply = NativeUtilities::AuthenticateU2F(static_cast<char*>(ptrToChallenge.ToPointer()));
    //clean up before return
    System::Runtime::InteropServices::Marshal::FreeHGlobal(ptrToChallenge);
    Managed_U2F_Reply^ managedReply = gcnew Managed_U2F_Reply();
    managedReply->ResultCode = reply->responseCode;
    if (managedReply->ResultCode == 0)
    {
        managedReply->Response = gcnew String(reply->response, 0, reply->length);
    }
    return managedReply;
}

struct u2f_reply
{
    int responseCode;
    int length;
    char* response;
};

u2f_reply* NativeUtilities::AuthenticateU2F(char* challenge)
{
    u2f_reply* reply = new u2f_reply();
    char response[2048] = { 0 };
    size_t response_len = sizeof(response);
    u2fh_devs* devs = NULL;
    u2fh_rc rc;
    u2fh_initflags flags = (u2fh_initflags)0;
    rc = u2fh_global_init(flags);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    rc = u2fh_devs_init(&devs);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    rc = u2fh_devs_discover(devs, NULL);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    rc = u2fh_authenticate2(devs, challenge, "https://demo.yubico.com", response, &response_len, U2FH_REQUEST_USER_PRESENCE);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    u2fh_devs_done(devs);
    u2fh_global_done();
    reply->length = response_len;
    reply->response = response;//adding printf here prints it out correctly, yet it doesn't when I call it in Utilities::AuthenticateU2F
    reply->responseCode = rc;
    return reply;
}

我希望它 return 一个带有响应数据的 json 对象，如下所示：https://developers.yubico.com/libu2f-host/，但我得到一个随机的 ASCII 字符串（无法粘贴）这里）并且没有错误

Answer 1

感谢 Hans Passant，我使用以下方法解决了这个问题：

u2f_reply* NativeUtilities::AuthenticateU2F(char* challenge)
{
    u2f_reply* reply = new u2f_reply();
    char response[2048] = { 0 };
    size_t response_len = sizeof(response);
    u2fh_devs* devs = NULL;
    u2fh_rc rc;
    u2fh_initflags flags = (u2fh_initflags)0;
    rc = u2fh_global_init(flags);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    rc = u2fh_devs_init(&devs);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    rc = u2fh_devs_discover(devs, NULL);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    rc = u2fh_authenticate2(devs, challenge, "https://demo.yubico.com", response, &response_len, U2FH_REQUEST_USER_PRESENCE);
    if (rc != U2FH_OK)
    {
        reply->responseCode = rc;
        return reply;
    }
    u2fh_devs_done(devs);
    u2fh_global_done();
    reply->length = response_len;
    reply->response = new char[response_len];
    memcpy_s(reply->response, response_len, response, response_len);
    reply->responseCode = rc;
    return reply;
}

Return 从本机代码到托管损坏了返回的对象

Return from native code to managed corrupts the returned object

c++

c++-cli

fido-u2f

yubico