wasm_injector

wasm_injector is a Rust-based command line utility to manipulate WebAssembly (wasm) modules. It allows you to inject code, compress, and hexify a given wasm module. This utility is especially useful when you need to modify wasm files for testing, optimization, or debugging.

Prerequisites

To use this utility, you need to have Rust installed on your system. If you don't have Rust installed, you can follow the official instructions here.

Installation

Clone the repository and build the project with cargo, Rust's package manager:

git clone https://github.com/LimeChain/wasm-injector.git
cd wasm-injector
cargo build --release

This will create an executable in the target/release directory.

Usage

• This project is developed to inject instructions in WASM modules or polkadot conformance testing. You can download a sample WASM file from here.
• The script will automatically unhexify and decompress WASM modules passed in as input
• The general format to run the wasm_injector is as follows:

Usage: wasm_injector <COMMAND>

Commands:
  inject   Inject invalid instructions into a wasm module
  convert  Convert from `hexified` and/or `compressed` to `raw` wasm module and vice versa
  help     Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Inject:

Inject invalid instructions into a wasm module

Usage: wasm_injector inject [OPTIONS] <injection> <function> <source> [destination]

Arguments:
  <injection>    [possible values: infinite-loop, bad-return-value, stack-overflow, noops, heap-overflow]
  <function>     The name of the exported function to be injected with the instructions
  <source>       Wasm source file path. Can be compressed and/or hexified
  [destination]  Destination file path (optional). If not specified, the output file will be a prefixed source file name

Options:
      --compressed  Compresses the wasm. Can be used with `--hexified`
      --hexified    Hexifies the wasm. Can be used with `--compressed`
  -h, --help        Print help

Convert:

Convert from `hexified` and/or `compressed` to `raw` wasm module and vice versa

Usage: wasm_injector convert [OPTIONS] <source> [destination]

Arguments:
  <source>       Wasm source file path. Can be compressed and/or hexified.
  [destination]  Destination file path (optional). If not specified, the output file will be a prefixed source file name

Options:
      --raw         Saves the file as raw wasm (default). Can not be used with `--compressed` or `--hexified`
      --compressed  Compresses the wasm (zstd compression). Can be used with `--hexified`
      --hexified    Hexifies the wasm. Can be used with `--compressed`
  -h, --help        Print help

Examples

Inject:

To inject code into a wasm file, compress and hexify it, you can run:

./wasm_injector inject noops validate_block my_wasm_file.wasm --compressed --hexified

To specify a custom destination path, you can run:

./wasm_injector inject noops validate_block my_wasm_file.wasm my_destination_directory/injected_new_file.wasm

Convert:

From Compressed and/or Hexified Wasm to Raw (default):

./wasm_injector convert --raw compressed_and_hexified_wasm_file.wasm.hex raw_wasm_file.wasm

or

./wasm_injector convert compressed_and_hexified_wasm_file.wasm.hex raw_wasm_file.wasm

From Raw Wasm to Compressed and/or Hexified:

./wasm_injector convert --hexified raw_wasm_file.wasm heified_wasm_file.wasm.hex

./wasm_injector convert  --compressed --hexified raw_wasm_file.wasm compressed_and_hexified_wasm_file.wasm.hex

Contributing

Please feel free to contribute to the project. For major changes, please open an issue first to discuss what you would like to change.

License

This project is licensed under MIT. See the LICENSE file for details.