For a official purpose, I had to build a basic application. But it was not a normal application, it had to be a BIOS app. I can code in C/C++ to some extent, but I don’t know how to do it in BIOS. So after many hours, I understood that the easiest way to run is below. Please note that some basics have been already configured as per found in the coreboot document.
In this post we will try to understand the memory more. From here we will be able tweak some parameters and obtain more information regarding how we can assigne values into the memory which we have allocated and then try to access them via pointer and dereference.
If we lookinto the code below, we can see that we have mapped a memory location at 0x404000 and we have called it my memory.
Qiling is an advanced binary emulation framework. It can emulate various types of archs and can be used to perform advanced operations as well. Below are some of the quick commands which are needed for my tasks.
python module from qiling import Qiling # import from qiling.const import QL_VERBOSE init code=b"\x90" ql = Qiling(code=code, archtype='x86', ostype='Linux', verbose=QL_VERBOSE.DISASM) register ql.arch.regs.read("EAX") # read register ql.arch.regs.write("EAX", 0xff) # write register memory ql.mem.get_mapinfo() #get memory related information ql.
In this guide we will try to explore if we can check for any mnemonics which we don’t want the CPU to execute. In the below example, we will try to block some specific commands from being executed in the CPU. The challenge is to convert rawbytes to assembly language again and check for prohibited mnemonics.
code # prohibit command # the objective is to block certain commands from qiling import Qiling from qiling.
In this segment we will take a sample code from the how to and try to execute according to our own. In this test, we will try to perform an simple addition and see how it goes. The below tutorial will be a very basic entry into the qiling framework where we will perform a simple addition.
addition To perform the addition, following code will be executed onto the CPU.
