The Synacor Challenge is a story driven collection of programming exercises and logic puzzles provided by the company Synacor.
I would say that the problems inside it range from beginner to intermediate difficulty, but overall it is a fun experience.
This repository contains some code and a writeup of my playthrough of this challenge.
The virtual machine is the file syn-vm.py. Run it with the -h option to see how to use it. For simply running a program, call the script with the desired binary file as input, like so.
./syn-vm.py challenge.bin
Syn-VM will allow you to save and load the machine state so that you can jump back into a session where ever you left off.
The save feature is a little hackish. You need to wait for the VM to request input, and then type in "debug: save". This will then create a file in your directory called "save.state" that you can then use to load from.
To load use the -l option.
./syn-vm.py -l foo.state
Syn-VM includes tracer functionality for debugging purposes. Specify the -t option, and it will create a file called "trace.out" in your directory that contains the exact instructions that were executed by the VM for that session.
./syn-vm.py -t program.bin
Syn-VM has an interactive debugger that you can use. With it you can go through instructions step by step, set and remove breakpoints, and change register values.
In order to keep the debugger output separate from the normal VM output, the VM output will be redirected to a file called "display.out" when in debug mode. The recommended workflow is to use two terminals and run the two following commands in them. (First command going to the first terminal, second command going to the second terminal.)
./syn-vm.py -d program.bin
tail -f display.out
The commands you can run from the debug menu are these.
| Command | Description |
|---|---|
| step | Step through one instruction |
| continue | Continue execution to the next breakpoint |
| set break <addr> | Set a breakpoint at the given address |
| remove break <addr> | Remove a breakpoint at the given address |
| display breaks | Display a list of the active breakpoints |
| set register <#> <value> | Set the # register to the given value |
These are programs to crack the key for the teleporter game-code. Simply compile and run them. The inputs are hard coded in.
This will try to disassemble syn-vm machine code to an assembly-like readable format. It doesn't do anything special for differentiating between code and data within a binary, but it should work well enough for most situations.
./disassembler.py program.bin
This is just a quick script that I wrote for printing a hexdump-like printout to the screen of a syn-vm binary. The reasoning was that hexdump was giving me addresses per byte, and I wanted addresses to be per word, so that I didn't have to constantly convert between the two when looking at a trace or disassembly. There probably is an option in hexdump to give me what I wanted, but this was quicker.
./print_dump.py program.bin
Solutions to most of the problems
Visualization and solution to the vault problem
A memory dump of the challenge.bin after it has run the self tests and decrypted itself