hi.d

Security Policy

A tool people run against every host they touch earns the obvious questions up front. This is the threat model: what hi does and deliberately doesn’t, what runs where, what it leaves behind, where the trust boundaries sit, and how to report what slipped through.

Contents

• What hi does - and deliberately doesn’t
• What runs where
• Footprint and cleanup on the target
• Trust boundaries
• Supported versions
• Reporting a vulnerability

What hi does - and deliberately doesn’t

• No network calls of its own. hi only execs the transports you already use (ssh, docker exec, podman exec, nomad alloc exec, kubectl exec) against a target you named. No telemetry, no update checks, no curl/wget anywhere in the shipped tree.
• No curl | bash. Installing is git clone plus scripts/install.sh, or a distro package (deb/rpm/apk, AUR, Homebrew) built from that same script. hi --update is git pull in a checkout you can read.
• The payload is an allow list. What goes over the wire is exactly $_HI_PAYLOAD at the top of hi.sh (common misc shells load.sh) - docs, tests, CI and editor config never leave the client. Your overlay (settings.sh, colors, packages from ~/.config/hi.d/) is a second, smaller allow list.
• base64 is armor, not crypto. The payload is base64-encoded so it survives the target’s login shell unmangled; it provides no confidentiality or integrity. Both come entirely from the transport (ssh, or the container runtime’s exec channel).

What runs where

hi.sh runs on the client: it parses arguments, picks the backend, tars and armors the payload, and pipes it over the transport. On the target, a single sh unpacks it into a temp directory and chainloads load.sh, which prints the header, grafts hi’s marker-delimited blocks onto the host’s rc files, and hands off to the best shell available. Everything the target executes was generated on the client.

Footprint and cleanup on the target

• The session tree lives in a mktemp -d directory (mode 0700, named <user>.hi.XXXXXX); the ssh bootstrap directory is created with mkdir -m 700.
• Removal has two independent paths: the bootstrap’s trap 'rm -rf $_HI_CLEANUP' exit, and load.sh’s own on-exit hook. tests/targets/ssh_disconnect_test.sh verifies cleanup fires on an abrupt disconnect, not just a clean exit.
• The rc additions sit between # hi-config-start and # hi-config-end markers and are stripped back out by that same on-exit hook.
• A target with a permanent ~/hi.d (you ran scripts/install.sh there) is used in place and nothing is deleted; the rc grafts are still cleaned on exit. That permanent tree never needs to be writable by you - root-owned, package-manager-installed copies work, because your config lives in ~/.config/hi.d/.
• On the client, install.sh validates your existing rc files with each shell’s own syntax checker before touching them, and --uninstall removes exactly what install wrote.

Trust boundaries

• hi’s security model is the transport’s security model. It adds no authentication, listens on nothing, and anyone positioned to intercept or control your ssh/container session could do so without hi in it.
• A malicious target gets what any interactive session gives it: your payload and a terminal. Treat your overlay (settings.sh, colors, packages) as public to every host you visit. Nothing a target sends back is ever executed on the client - the one string hi reads back (the probe for an existing ~/hi.d) is only interpolated into the script sent back to that same target. Escape sequences in session output remain possible, exactly as with plain ssh.
• Backend dispatch trusts your local ~/.ssh/config and your docker/podman/nomad/kubectl CLIs - the same ones you already run by hand.

Supported versions

There is no tagged release yet: the supported version is the tip of main. Once v1.0 is tagged, this section becomes a version table, with the latest release supported.

Reporting a vulnerability

Please don’t open a public issue for anything exploitable. Instead, either:

• report privately via GitHub private vulnerability reporting, or
• email ivylikethevine@gmail.com.

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