didericis
49c2ed0b93
Port the smolmachines backend so BOT_BOTTLE_BACKEND=smolmachines works on Linux (KVM), not just macOS: - Preflight gates /dev/kvm presence + accessibility on Linux with actionable remediation (kvm module, kvm group). - smolvm state-DB path is platform-derived (XDG on Linux). - force_allowlist runs on both platforms and is fail-closed: it verifies the persisted TSI allowlist and dies rather than booting a VM whose egress confinement it can't confirm. Previously it no-oped on Linux, failing OPEN. - allocate() does per-bottle 127.0.0.<N> scoping on Linux too (no ifconfig needed — all of 127/8 is already loopback); only ensure_pool's lo0 aliasing stays macOS-only. - README documents Linux + NixOS host setup. Linux/KVM integration (the sandbox-escape acceptance gate) is pending verification on a NixOS host; unit tests cover the new platform branches. Issue: #283 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NkwFXLFff9PYPy4wgVBJp9
83 lines
3.2 KiB
Python
83 lines
3.2 KiB
Python
"""Slug / preflight / subnet helpers for the smolmachines backend
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(PRD 0023). Kept in its own module so the renderers can be
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unit-tested without importing the docker subprocess paths."""
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from __future__ import annotations
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import hashlib
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import os
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import platform
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import shutil
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from ...log import die
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# libkrun's Linux backend drives the guest through KVM, so the host
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# must expose `/dev/kvm` and the invoking user must be able to open
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# it. macOS uses Hypervisor.framework and needs no device node.
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_KVM_DEVICE = "/dev/kvm"
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def smolmachines_preflight() -> None:
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"""Ensure the host can run the smolmachines backend before the
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launch flow starts. Called from `_resolve_plan`; surfaces a
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clear, actionable error instead of a cryptic `smolvm` failure
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deep in launch.
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Checks `smolvm` is on PATH (both platforms) and, on Linux,
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that `/dev/kvm` exists and is accessible. `gvproxy` is no
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longer required — see the PRD's design pivot section."""
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if shutil.which("smolvm") is None:
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die(
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"BOT_BOTTLE_BACKEND=smolmachines requires `smolvm` on "
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"PATH. Install with: "
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"curl -sSL https://smolmachines.com/install.sh | sh. "
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"To use the legacy Docker backend instead, set "
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"BOT_BOTTLE_BACKEND=docker or pass --backend=docker."
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)
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if platform.system() == "Linux":
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_preflight_kvm()
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def _preflight_kvm() -> None:
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"""Linux-only: libkrun needs `/dev/kvm`. Distinguish 'KVM not
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enabled' from 'no permission' so the operator knows which to
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fix."""
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if not os.path.exists(_KVM_DEVICE):
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die(
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f"BOT_BOTTLE_BACKEND=smolmachines needs {_KVM_DEVICE} on "
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"Linux but it is missing. Enable KVM: load the kvm-intel "
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"or kvm-amd kernel module (and confirm virtualization is "
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"enabled in BIOS/firmware). To use the legacy Docker "
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"backend instead, set BOT_BOTTLE_BACKEND=docker."
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)
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if not os.access(_KVM_DEVICE, os.R_OK | os.W_OK):
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die(
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f"{_KVM_DEVICE} exists but is not readable/writable by the "
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"current user. Add your user to the `kvm` group "
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"(`sudo usermod -aG kvm \"$USER\"`) and re-login, or run "
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"with access to the device."
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)
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def smolmachines_bundle_subnet(slug: str) -> tuple[str, str, str]:
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"""Derive a per-bottle docker subnet + gateway IP + bundle IP
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from the slug.
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Returns `(subnet_cidr, gateway_ip, bundle_ip)`. The third
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octet comes from SHA-256 of the slug mod 254 (skipping 17 to
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avoid the docker-default bridge), so parallel bottles get
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distinct /24s and `resume` reuses the same /24. The bundle
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container always lands at `.2`; gateway is `.1`; the smolvm
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Smolfile's `allow_cidrs` is `<bundle_ip>/32`."""
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digest = hashlib.sha256(slug.encode("utf-8")).digest()
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octet = (digest[0] % 254) + 1
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# Skip the docker-default bridge to dodge the most common
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# collision (operators with `docker0` at 172.17.x.x or a
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# 192.168.17.x VPN client).
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if octet == 17:
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octet = 18
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subnet = f"192.168.{octet}.0/24"
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gateway = f"192.168.{octet}.1"
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bundle_ip = f"192.168.{octet}.2"
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return subnet, gateway, bundle_ip
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