Laika/CONTRIBUTING.md

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.

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

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.