Anvil

Pure-Rust SSH stack for Git tooling — transport, keys, signing, agent.

Anvil is the foundation library extracted from Steelbore/Gitway. It packages everything Git needs from SSH, and nothing it doesn't: pinned-host transport, key generation, SSHSIG commit signing, and an SSH agent (client + daemon). Pure Rust end to end. No C runtime at link time. #![forbid(unsafe_code)] in project-owned code.

Status

v0.1.0 — initial cold-start extraction from Steelbore/Gitway @ 28abee6. Pre-1.0; the public type names will rename in 0.2.0 (see CHANGELOG). Full v1.0 scope and roadmap live in the Gitway PRD.

Use

[dependencies]
anvil-ssh = "0.1"

use anvil_ssh::{GitwayConfig, GitwaySession};

#[tokio::main]
async fn main() -> Result<(), anvil_ssh::GitwayError> {
    let config = GitwayConfig::github();
    let mut session = GitwaySession::connect(&config).await?;
    session.authenticate_best(&config).await?;
    let exit_code = session.exec("git-upload-pack 'steelbore/gitway.git'").await?;
    session.close().await?;
    Ok(())
}

The type names (GitwaySession, GitwayConfig, GitwayError) are inherited from the source crate. They will be renamed to AnvilSession / AnvilConfig / AnvilError in 0.2.0 with #[deprecated] aliases for one major version.

Modules

Module	Purpose
`session`	russh-backed SSH session lifecycle
`auth`	Identity discovery (CLI flag → `~/.ssh` paths → SSH agent)
`hostkey`	Pinned host fingerprints (GitHub, GitLab, Codeberg)
`relay`	Bidirectional stdin/stdout/stderr relay over an exec channel
`keygen`	Ed25519 / ECDSA / RSA keypair generation in OpenSSH format
`sshsig`	SSHSIG sign / verify / `find-principals` / `check-novalidate`
`allowed_signers`	Parser for git's `allowed_signers` file format
`agent::client`	Blocking SSH agent client (`ssh-add` equivalent)
`agent::daemon`	Async SSH agent server (`ssh-agent` equivalent)
`agent::askpass`	`$SSH_ASKPASS`-driven interactive confirmation
`diagnostic`	Single-line stderr failure diagnostic helper
`time`	ISO 8601 timestamp helpers (no `chrono` / `time` crate dep)

Crypto backends

Anvil layers two pure-Rust crypto stacks:

Transport — russh with the aws-lc-rs backend (post-quantum-ready; no CMake on non-FIPS builds).
Keys + signing — RustCrypto (ed25519-dalek, rsa, p256/384/521) via ssh-key.

PrivateKey values never cross the boundary between the two stacks.

Build

cargo build --release
cargo test
cargo clippy --all-targets -- -D warnings
cargo fmt --check

perl is required by aws-lc-rs for assembly pre-processing on every platform; nasm is also required on Windows MSVC.

License

Steelbore/Gitway — primary consumer; the full Git-over-SSH toolkit (gitway, gitway-keygen, gitway-add binaries) built on top of Anvil.

anvil-ssh 0.1.0