[PATCH] crypt32: Support CERT_QUERY_OBJECT_BLOB in CRYPT_QueryEmbeddedMessageObject().

[Hans Leidekker]

On Mon, 2022-03-28 at 14:01 +0300, Paul Gofman wrote:
> -    if (dwObjectType != CERT_QUERY_OBJECT_FILE)
> +    if (dwObjectType == CERT_QUERY_OBJECT_BLOB)
>      {
> -        WARN("don't know what to do for type %ld embedded signed messages\n",
> -         dwObjectType);
> +        WCHAR temp_path[MAX_PATH], temp_name[MAX_PATH];
> +        const CERT_BLOB *b = pvObject;
> +
> +        TRACE("cbData %lu, pbData %p.\n", b->cbData, b->pbData);
> +
> +        if (!GetTempPathW(MAX_PATH, temp_path) || !GetTempFileNameW(temp_path, L"blb", 0, temp_name))
> +        {
> +            ERR("Failed getting temp file name.\n");
> +            return FALSE;
> +        }
> +        file = CreateFileW(temp_name, GENERIC_READ | GENERIC_WRITE, 0,
> +                NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_DELETE_ON_CLOSE, NULL);
> +        if (file == INVALID_HANDLE_VALUE)
> +        {
> +            ERR("Could not create temp file.\n");
> +            SetLastError(ERROR_OUTOFMEMORY);
> +            return FALSE;

It would be nice to avoid creating a temporary file. Perhaps we could factor out
a helper that operates on memory and rewrite CryptSIPRetrieveSubjectGuid() to 
use a file mapping?