Re: [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?