Rust Patcher

Secure fully decentralized software updates.

Implementation Flow

1. Add dependency

# Cargo.toml
[dependencies]
rustpatcher = "0.2"
tokio = { version = "1", features = ["rt-multi-thread","macros"] }

2. Embed owner public key and start the updater

#[tokio::main]
#[rustpatcher::public_key("axegnqus3miex47g1kxf1j7j8spczbc57go7jgpeixq8nxjfz7gy")]
async fn main() -> anyhow::Result<()> {

    // Only in --release builds, not intended for debug builds
    rustpatcher::spawn(rustpatcher::UpdaterMode::At(13, 40)).await?;

    println!("my version is {:?}", rustpatcher::Version::current()?);
    
    // your app code after this
    loop {
        tokio::select! {
            _ = tokio::signal::ctrl_c() => {
                println!("Exiting on Ctrl-C");
                break;
            }
        }
    }
    Ok(())
}

3. Generate signing key (one-time)

cargo install rustpatcher
rustpatcher gen ./owner_key

Output includes:

• Owner signing key saved to ./owner_key (z-base-32 encoded)
• Owner public key (z-base-32)
• Attribute snippet to paste into main: #[rustpatcher::public_key("")]

4. Build and sign releases

# build your binary
cargo build --release

# sign the compiled binary in-place
rustpatcher sign target/release/<your-bin> --key-file=./owner_key

5. Publish updates

• Run the newly signed binary on at least one node until a couple of peers have updated themselfs.
• The running process periodically publishes the latest PatchInfo to the DHT.
• Clients discover new PatchInfo, fetch the patch from peers, verify, and self-replace.

Run Example: simple

git clone https://github.com/rustonbsd/rustpatcher
cd rustpatcher
cargo build --release --example simple
cargo run --bin rustpatcher sign target/release/examples/simple --key-file ./owner_key_example

# Run signed app:
./target/release/examples/simple


# if you increase the version in /crates/rustpatcher/Cargo.toml  
# and build+sign+start another node, then the first 
# node will update via the second node.

Network Architecture

sequenceDiagram
    participant Owner as Owner Node (new version)
    participant DTT as DHT Topic Tracker
    participant Peer as Peer Node (old)

    Owner->>DTT: Publish PatchInfo(version, size, hash, sig)
    Peer->>DTT: Query latest PatchInfo (minute slots)
    DTT-->>Peer: Return newest records
    Peer->>Owner: Iroh connect (ALPN /rustpatcher/<owner>/v0)
    Peer->>Owner: Auth = sha512(pubkey || unix_minute)
    Owner-->>Peer: OK + Patch (postcard)
    Peer->>Peer: Verify(hash, size, ed25519(pubkey))
    Peer->>Peer: Atomic replace + optional execv restart

• Discovery: distributed-topic-tracker minute-slotted records over the DHT
• Transport: iroh QUIC, ALPN namespaced per owner key
• Authentication: rotating hash auth per minute bucket

Key Processes

1. Version propagation

• Running a node publishes a PatchInfo record roughly every minute.
• Records are minute scoped with short TTL to avoid staleness.
• Peers scan current and previous minute for latest version.

2. Patch fetch + verification

• Peer connects to other peers with newer version via iroh using an ALPN derived from the owner pubkey.
• Auth: sha512(owner_pub_key || unix_minute(t)) for t ∈ {-1..1}.
• Owner sends the signed patch (postcard-encoded).

3. Self-update mechanism

• Write to temp file
• Atomic self-replace
• Optional immediate restart via execv (UpdaterMode::Now) or deferred (OnRestart / At(hh, mm))

Data Embedded in the Binary

• Fixed-size embedded region in a dedicated link section (.embedded_signature)
• Layout:
  • 28 bytes: bounds start marker
  • 32 bytes: binary hash (sha512 truncated to 32)
  • 8 bytes: binary size (LE)
  • 64 bytes: ed25519 signature
  • 16 bytes: ASCII version (padded)
  • 28 bytes: bounds end marker

At runtime, the library:

• Locates the embedded region
• Parses version/hash/size/signature
• Verifies the binary contents against the signed metadata

CLI Reference (rustpatcher)

• gen
  • Generates a new ed25519 signing key in z-base-32; prints the public key and attribute snippet.
• sign --key-file
  • Reads the compiled binary, computes PatchInfo, and writes it into the embedded region.

DO NOT COMMIT YOUR PRIVATE KEY!

# add this to your .gitignore
owner_key*

Notes:

• Keys are z-base-32 encoded on disk, the public key is embedded in code via #[rustpatcher::public_key("...")].
• Signing must be re-run after each new build that is intendet to self update.
• For every build target a seperate keypair is required (we don't want the arm users patching in x86 binaries).

Library API (overview)

• #[rustpatcher::public_key("")]
  • Embeds the owner public key and the package version for verification
• rustpatcher::spawn(mode: UpdaterMode) -> Future<Result<()>>
  • Starts discovery, publishing, distribution server, and updater
• UpdaterMode::{Now, OnRestart, At(h, m)}

How It Changed (vs previous rustpatcher)

• Single embedded region with explicit bounds, constant size, and zero-allocation compile-time construction
• Signature scheme clarified and minimal:
  • sha512(data_no_embed) -> first 32 bytes as hash
  • sign sha512(version || hash || size_le) with ed25519
• Owner key embedding via attribute macro, version captured from CARGO_PKG_VERSION and embedded as fixed-length ASCII
• Minute-slotted record publishing and discovery via distributed-topic-tracker
• iroh-based distributor with rotating minute auth derived from owner public key
• Simple updater modes: Now, OnRestart, At(hh:mm)
• CLI split: cargo install rustpatcher to manage keys and sign releases

Example

use rustpatcher::UpdaterMode;

#[tokio::main]
#[rustpatcher::public_key("axegnqus3miex47g1kxf1j7j8spczbc57go7jgpeixq8nxjfz7gy")]
async fn main() -> anyhow::Result<()> {

    rustpatcher::spawn(UpdaterMode::At(02, 30)).await?;

    // app code...
    Ok(())
}

Release Workflow

1. Generate key (once):

• rustpatcher gen ./owner_key

2. Build + sign each release:

• cargo build --release
• rustpatcher sign target/release/ --key-file=./owner_key

3. Deploy and run the signed binary on at least one node:

• It will publish PatchInfo and serve patches to peers.
• No need to have any exposed ports.

build:
    cargo build --release
    rustpatcher sign target/release/<your-bin> --key-file ./owner_key

publish:
    target/release/<your-bin>