Possible memory safety issue

[zeon256]

Problem 1

The use of Vec::from_raw_parts usage, in this case, is not safe the as the data is not allocated by the same allocator. Dropping this Vec may corrupt the internal data structures of the allocator.

Proposed solution

/// Wrapper around DPAPI `CryptUnprotectData`
pub fn crypt_unprotect_data(data_buf: &mut [u8]) -> Result<Vec<u8>, DumperError> {
    let buf_ptr = data_buf.as_mut_ptr();
    let buf_len = data_buf.len();
    let mut data_in = DATA_BLOB {
        cbData: buf_len as u32,
        pbData: buf_ptr,
    };

    let mut data_out = unsafe { std::mem::zeroed() };

    let unprotect_result = unsafe {
        CryptUnprotectData(
            &mut data_in,
            ptr::null_mut(),
            ptr::null_mut(),
            ptr::null_mut(),
            ptr::null_mut(),
            0,
            &mut data_out,
        )
    };

    if unprotect_result == 0 {
        let error = unsafe { GetLastError() };
        return Err(DumperError::DpapiFailedToDecrypt(error));
    }

    let size = data_out.cbData as usize;
    let v = unsafe { slice::from_raw_parts(data_out.pbData, size).to_vec() };
    Ok(v)
}