CONTRIBUTING to Laika

HEAD: https://github.com/CPunch/Laika/tree/main

Directories explained

/cmake-modules holds helper functions for CMake.
/lib is a shared static library between the bot, shell & CNC. LibSodium is also vendor'd here.
/cnc is the Command aNd Control server. (Currently only targets Linux)
/bot is the bot client to be ran on the target machine. (Targets both Linux and Windows)
/shell is the main shell to connect to the CNC server with to issue commands. (Currently only targets Linux)
/tools holds tools for generating keypairs, etc.

Coding style

Laika uses clang-format to enforce a consistent style across the codebase. Before committing changes, make sure to run git clang-format and add the changes to the commit. Pull requests with wrong styling will be rejected.

Tasks and TODOs

Looking for some simple tasks that need to get done for that sweet 'contributor' cred? Check here!

Change lib/lin/linshell.c to use openpty() instead of forkpty() for BSD support
Fix address sanitizer for CMake DEBUG builds
Change laikaT_getTime in lib/src/ltask.c to not use C11 features
Implement more LAIKA_BOX_* VMs in lib/include/lbox.h
Follow GNU GPL license guidelines (read 'How to Apply These Terms to Your New Programs')

Lib: Error Handling

Error handling in Laika is done via the 'lerror.h' header library. It's a small and simple error handling solution written for laika, however can be stripped and used as a simple error handling library. Error handling in Laika is used similarly to other languages, implementing a try & catch block and is achieved using setjmp(). The LAIKA_ERROR(...) is used to throw errors.

Example:

LAIKA_TRY
    printf("Ran first\n");
    LAIKA_ERROR("Debug message here\n");
    printf("You'll never see this\n");
LAIKA_CATCH
    printf("Ran second!\n");
LAIKA_TRYEND

printf("Ran last!\n");

Some minor inconveniences include:

return or other control-flow statements that leave the current scope cannot be used in the LAIKA_TRY or LAIKA_CATCH scopes.
max of 32 depth, avoid using recursively.
not thread safe.

Lib: Packet Handlers

Laika has a simple binary protocol & a small backend (see lib/src/lpeer.c) to handle packets to/from peers. lib/include/lpacket.h includes descriptions for each packet type. For an example of proper packet handler definitions see bot/src/bot.c. It boils down to passing a sLaika_peerPacketInfo table to laikaS_newPeer. To add packet handlers to the bot, add your handler info to laikaB_pktTbl in bot/src/bot.c. To add packet handlers to the shell, add your handler info to shellC_pktTbl in shell/src/sclient.c. For adding packet handlers to cnc, make sure you add them to the corresponding table in cnc/src/cnc.c, laikaC_botPktTbl for packets being received from a bot peer, laikaC_authPktTbl for packets being received from an auth peer (shell), or DEFAULT_PKT_TBL if it's received by all peer types (things like handshakes, keep-alive, etc.)

Lib: Task Service

Tasks can be scheduled on a delta-period (call X function every approximate N seconds). laikaT_pollTasks() is used to check & run any currently queued tasks. This is useful for sending keep-alive packets, polling shell pipes, or other repeatably scheduled tasks. Most laikaT_pollTasks() calls are done in the peerHandler for each client/server.

Lib: VM Boxes

Laika has a tiny VM for decrypting sensitive information. For details on the ISA read lib/include/lvm.h, for information on how to use them read lib/include/lbox.h. Feel free to write your own boxes and contribute them :D

Bot: Platform-specific backends

bot/win and bot/lin include code for platform-specific code that can't be quickly "ifdef"d away. These mainly include stuff like persistence or opening pseudo-ttys.

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