hotpatch

Hotpatch is a library designed to hot patch Linux executables by injecting .so files into already running processes. This allows for dynamic modification of process behavior without interrupting execution, making it useful for runtime patching, debugging, or introducing new functionality into live applications.

The tool includes the hotpatcher command-line utility, which simplifies the injection process by targeting a specific process ID (PID). It supports options for verbose logging, dry runs, symbol invocation, and execution pointer manipulation, providing flexibility for various patching scenarios.

Use cases include security research, exploit development, and runtime analysis where altering process memory or injecting code is necessary without restarting the target.

Hotpatch uses a C API (also C++ compatible) to inject a shared library (.so) into a running process identified by PID. The hotpatcher utility facilitates this by loading the .so file into the target process's memory space. It can invoke specific symbols from the library, reset or set the execution pointer to a symbol, and supports dry-run mode to simulate without modification. The injection occurs without halting the target process, leveraging Linux dynamic linking mechanisms.