zexec

zexec allows users to safely execute remote commands on a server. It relies on Zenroom to check that a certain user can execute a certain command. It does so by storing a Zenroom contract and the user public keys; the user trigger the command by sending it along with its signature. zexec will execute the Zenroom contract and, if the signature matches, it will execute the command requested.

Features

• Cryptographically secure by using Zenroom
• Small and static executable

Getting started

Binary relaese

There is no binary release yet, you need to compile zexec from the source code.

Compiling from the source

zexec requires the nightly version of the Rust toolchain; rustup can be used to download and setup Rust.

In addition, Zenroom requires the following dependencies:

• clang
• cmake
• linux-headers
• llvm
• meson
• xxd (usually contained in the vim package)
• zsh

Nightly rustc

Some dependancies require a nightly or dev build of rust to run. An easy way to solve this is:

rustup default nightly

After the dependencies have been installed and rust set to nightly, run the following command:

cargo build --release

Usage

zexec looks by default in the folder /etc/zexec, as defined here and saves output into /var/lib/zexec/logs/. Create both folders and copy the "command" smart contract to /etc/zexec

sudo mkdir /etc/zexec
sudo mkdir -p /var/lib/zexec/logs/
sudo cp ./contracts/* /etc/zexec

To run zexec:

sudo ./target/release/zexec

It will by default listen on the port 9856 on the localhost address. You can change it by respectively using -p and -a in the command line.

Then you can pass it data via a POST, for example using curl:

curl -X POST "http://127.0.0.1:9856/contracts/command" -H  "accept: application/json" -H  "Content-Type: application/json" -d "{\"Alice\":{\"signature\":{\"r\":\"5n2RrZFIxuQtETEfKfQwPhR7FvW4hfxOGn2bQOz69gs=\",\"s\":\"vZMggPH3U2A30IwwzTUpLRLNVeUoUjWlG3/wDZaOXbM=\"}},\"command\":\"ls\"}"

Zexec should then return the name of the file, where it logged the output of the command passed in the POST (a simple "ls" in this case), which you can find in the folder /var/lib/zexec/logs/.

License

zexec is written and maintained by Jaromil Rojo (@jaromil) and Danilo Spinella (@danyspin97). It is licensed under the GPL-3.0.