feat(smolmachines): per-bottle loopback alias scopes TSI to single /32 #76

Merged
didericis-claude merged 4 commits from smolmachines-loopback-alias-scoping into main 2026-05-27 18:08:02 -04:00

4 Commits

Author SHA1 Message Date
didericis-claude 2f143c7142 fix(smolmachines): include per-bottle alias in NO_PROXY
test / unit (pull_request) Successful in 26s
test / integration (pull_request) Successful in 39s
claude's HTTPS_PROXY was catching the supervise MCP URL
(`http://<alias>:<port>/`) because NO_PROXY was hardcoded to
`localhost,127.0.0.1` and didn't include the per-bottle
loopback alias. Claude proxied the MCP POST through egress,
egress had no route for the alias, and the connection failed
— `/mcp` showed "supervise · ✘ failed" inside the bottle.

Append the loopback alias to NO_PROXY in launch.py so direct
MCP calls bypass the proxy. The git-gate URL uses `git://`,
which proxies don't touch, so this only affects MCP / HTTP
paths to the bundle.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-27 17:17:00 -04:00
didericis-claude 7eda2a66ec feat(smolmachines): patch smolvm state DB to actually enforce per-bottle allowlist
test / unit (pull_request) Successful in 26s
test / integration (pull_request) Successful in 44s
Earlier commit framed this PR as "infrastructure landed, TSI
enforcement blocked on upstream smolvm 0.8.0." Found a clean
workaround that lets us enforce now.

Smolvm persists each machine's config (including
`allowed_cidrs`) as a JSON BLOB in
`~/Library/Application Support/smolvm/server/smolvm.db`,
`vms.data`. `machine create --allow-cidr X/32` silently writes
`allowed_cidrs: null` to that row when combined with `--from`,
but smolvm reads the row at `machine start` — so patching the
row between create and start sets the allowlist for real.

New `loopback_alias.force_allowlist(machine_name, cidrs)` opens
the SQLite DB, JSON-decodes the row, sets `allowed_cidrs`, and
writes back as BLOB (Text type silently corrupts smolvm's
later reads). launch.py calls it immediately after
`machine_create` and before `machine_start`.

Verified end-to-end on macOS / Docker Desktop:

  VM allowlist after start: ["127.0.0.16/32"]
  VM → 127.0.0.1:3000      → BLOCKED (Permission denied)
  VM → 8.8.8.8:53          → BLOCKED (Permission denied)
  VM → 127.0.0.16:<bundle> → CONNECTED

The DB-patch hack is correct only because smolvm reads
`allowed_cidrs` from the row at start time (not derived in-
process). When upstream honors `--allow-cidr` with `--from`,
the call becomes redundant — drop the call and the workaround
is gone.

Tests: 4 new for `force_allowlist` (BLOB round-trip; Linux
no-op; missing DB; missing row). Total 593 unit tests pass.

README + PRD updated to reflect the fix landed (no longer
"infrastructure pending upstream"). gitea#75 can close.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-27 16:55:03 -04:00
didericis-claude a919268d5e docs: honest framing of upstream smolvm 0.8.0 allowlist bug
test / unit (pull_request) Successful in 26s
test / integration (pull_request) Successful in 40s
PR #76 originally claimed the per-bottle alias scoping closed
gitea#75 ("agent can reach host loopback"). Verified
empirically that's not actually true: `smolvm 0.8.0 machine
create --from <smolmachine> --net --allow-cidr X/32` silently
drops the allowlist (`agent.config.json` shows `allowed_cidrs:
null`, and the running VM reaches all of `127.0.0.0/8`
regardless).

So the alias-allocation + alias-bind infrastructure is correct
pre-work, but the actual TSI enforcement is blocked on an
upstream smolvm bug. README + PRD 0023 + the module docstring
get reworded to say so plainly. gitea#75 stays open.

Workarounds tried (all dead-ends):
- `machine update --allow-cidr` doesn't exist
- stop-edit-`agent.config.json`-restart fails (smolvm removes
  the file on stop)
- `--smolfile` is mutually exclusive with `--from`
- `--image localhost:<port>/...` fails because smolvm's agent
  process can't reach host loopback during pull

When upstream lands a fix, our existing code (alias allocation,
port-bind, --allow-cidr in launch) will scope correctly without
further changes.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-27 16:37:56 -04:00
didericis-claude 2edc1abb9a feat(smolmachines): per-bottle loopback alias scopes TSI to single /32
test / unit (pull_request) Successful in 27s
test / integration (pull_request) Successful in 41s
PR #74's Docker-Desktop fix routed the agent through
`127.0.0.1:<random>` loopback forwards, but TSI filters by IP
only — so the allowlist `127.0.0.1/32` let the agent VM reach
**any** host service on macOS loopback (postgres, dev servers,
other bottles' published ports, mDNSResponder, ...). Real
downgrade vs the docker backend's `--internal` network.

Resolution: per-bottle loopback alias.

- New `loopback_alias` module manages a pool of
  `127.0.0.16` .. `127.0.0.31` on `lo0`. macOS only routes
  `127.0.0.1` by default; the extras need `sudo ifconfig lo0
  alias`. `ensure_pool()` lazily adds the missing entries via
  one sudo prompt on first launch per reboot — aliases persist
  on `lo0` until reboot, so subsequent launches skip the
  prompt entirely.
- `allocate(slug)` picks the lowest-numbered unused alias by
  inspecting running bundle containers' port-binding HostIps.
  No on-disk reservation — docker is the source of truth.
- Bundle bringup binds published ports to the allocated alias
  (`docker run -p <alias>::<port>`) instead of `127.0.0.1`.
- TSI allowlist becomes the alias's /32 — narrows reachability
  to this bottle's bundle only.
- Linux native daemons share the host's network namespace;
  `127.0.0.0/8` works without aliases, so the module no-ops on
  non-Darwin and returns `127.0.0.1` from `allocate`.

Tracking issue closed: gitea/issues/75.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-27 16:23:17 -04:00