Commit Graph

5 Commits

Author SHA1 Message Date
José Almeida cbc573b0a0 fix(ssh): reject invalid ssh_port + retry in-net keyscan + restore D5 + doc count
executor_ssh.targetFromMetadata: reject malformed / out-of-range
ssh_port instead of silently falling back to 0 → 22 in the resolver.
"abc", "0", "70000" all now return a "must be 1-65535" error so a
broken config can't masquerade as a successful launch routed through
port 22. Cubic P2.

scanFingerprintInsideNetwork (bastion fixture): retry on empty output.
Mirrors the host-side scanFingerprintViaHost retry loop — sshd accepts
TCP before host-key negotiation completes on a cold container, so the
keyscan can come back empty on the first try. Bound at 15s; surfaces
"status=..., stderr=..." on final failure for diagnosis. Cubic P2.

executor-crud D5 (changing config…): restore the seeded executor in a
try/finally. The test pinned the executor to host=10.255.255.1 to
verify the snapshot stayed sticky on the live session, but never put
the real host back, so any later spec in the same worker that reused
seedData.sshExecutorId would dial the unroutable address and hang.
Cubic P2.

e2e-plan.md: replace the "roughly 75" estimate with the actual 80 /
17-files current count plus the ~2.4 min wall-clock. Cubic P3.
2026-05-18 00:05:15 +01:00
José Almeida 2a342927e7 fix(ssh): defend launch + handshake against several real bugs
manager_launch: trusted exec-config keys override req.Metadata.
  buildLaunchMetadata applied executor config only when the matching
  key was missing in req.Metadata. A request that carried metadata.
  ssh_host_fingerprint (or ssh_host, ssh_identity_*) could pivot the
  launch to a different target and bypass the pinned fingerprint.
  Pin a list of connection-routing keys (ssh_host, ssh_port, ssh_user,
  ssh_host_fingerprint, ssh_identity_source, ssh_identity_file,
  ssh_proxy_jump) and have the executor config always win for those.
  Cubic / CodeRabbit P1.

executor_ssh.CreateInstance: reuse the resumed session state.
  ResumeRemoteInstance attaches the recovered ssh.Client + forwarder
  to r.sessions[InstanceID] and refreshes metadata, then the lifecycle
  manager unconditionally called CreateInstance, which dialed a fresh
  client and started a second remote agentctl on top of the live one
  — leaking the resumed state. CreateInstance now early-returns from
  the existing r.sessions entry via buildResumedInstance. Cubic P1.

executor_ssh.Close: actually release tracked sessions.
  After dropping the SSHConnPool, Close was a no-op. A hard kandev
  exit (no per-session StopInstance) left forwarders and SSH clients
  open. Iterate r.sessions and Close the forwarder + client for each.
  Cubic P2.

buildAuthMethods: close the ssh-agent unix socket after handshake.
  Each agent-authenticated dial opened net.Dial("unix", $SSH_AUTH_SOCK)
  and never closed it; only PublicKeysCallback held the agent.Client
  reference and that callback is consulted exactly once at handshake.
  Return a cleanup func from buildAuthMethods + buildClientConfig and
  defer it from dialSSH / dialViaJump so the socket releases as soon
  as key exchange completes. Greptile P1 security.

waitAgentctlHealthy: probe HTTP /health, not just the TCP listener.
  The local port is owned by the SSH forwarder, which Accepts before
  it Dials the remote direct-tcpip channel — a TCP connect can succeed
  before the channel actually establishes. Issue a real GET /health
  and require a 2xx so a broken tunnel surfaces here rather than at
  the first agent operation. Cubic P1.

ssh-connection-card: also gate the trust + save on in-flight tests.
  Editing a connection field during a pending test silently kept
  resultStale=false because prev.result was still null; when the test
  returned, the new fingerprint was bound to the old form values but
  the gate let the user trust + save anyway. Treat in-flight tests as
  prior tests for staleness purposes, and preserve resultStale across
  the test's success setState. Cubic P2.
2026-05-18 00:05:15 +01:00
José Almeida a30833b336 refactor(ssh): drop the unused conn pool + remote curl dependency
CodeRabbit and Greptile both flagged the SSHConnPool: the executor never
took the pool path (CreateInstance always dialDirect'd a fresh client and
parked it on sshSessionState), so the pool's keepalive goroutines and
refcount logic were dead code. Get() also overwrote map entries on every
call, which would have leaked keepalive goroutines if the pool *had* been
used. Delete the entire SSHConnPool + sshConnKey + pooledConn + keepalive
plumbing. Export DialSSH so the SSH test endpoint can dial directly and
close the client when its single-shot probe is done.

While here:
  * pickRemoteAgentctlPort: switch from time.Now().UnixNano()%20000 to
    math/rand/v2.IntN. Two concurrent CreateInstance calls on a fast
    machine were getting the same port (UnixNano cycles in ~20µs through
    the 20k range); randomized picks avoid the collision.
  * createRemoteAgentInstance: POST to the remote control port over a
    direct-tcpip dial via net/http instead of shelling out to `curl`. The
    sshd container no longer needs curl, the kandev test endpoint no
    longer needs to probe for it, and the call inherits Go's standard
    timeout + error handling. Drop `curl` from the e2e Alpine image.
  * maybeUploadCredentials: was probing `printf %s "$HOME"` and
    discarding the output, then allocating an unused sshFileUploader.
    SSH v1 doesn't ship credential upload — just log a warning when a
    user sets remote_credentials so they know it won't take effect, and
    delete the dead uploader file.
2026-05-18 00:05:15 +01:00
José Almeida 39c574bd57 fix(ssh): make the end-to-end launch path actually work
A pass of issues uncovered by running the SSH e2e suite locally
(KANDEV_E2E_CONTAINERS=1 against the real sshd container). After this
commit all 15 non-launch SSH e2e tests pass (UI form validation,
test-connection contract, auth-methods, error-surfacing, sessions-card
empty state) and the launch path runs through prepare -> upload ->
agentctl -> instance -> forward, with WebSocket streams sometimes
disconnecting partway through (tracked below for follow-up).

Image changes (apps/web/e2e/fixtures/ssh-image.ts):
- Install curl so the SSH executor can POST to the in-container
  agentctl control server for instance creation.
- Install gcompat + libstdc++ so the dynamically-linked glibc
  agentctl binary can exec on musl-libc Alpine. Without it the
  kernel returns ENOENT for /lib64/ld-linux-x86-64.so.2.
- Install shadow + 'usermod -p *' kandev so sshd doesn't refuse
  pubkey auth for the otherwise-locked user.
- Drop in 'AllowTcpForwarding yes' and 'MaxSessions 100' via
  /etc/ssh/sshd_config.d/. Alpine's defaults are 'no' and 10, both
  of which crater the SSH executor's port-forward path.
- chown /home/kandev/.kandev to kandev on entrypoint so a host
  bind-mount of that path (used in this commit for log persistence)
  doesn't make agentctl unable to write its log file.

Image helper (apps/web/e2e/helpers/ssh.ts):
- Bind-mount the host mock-agent-linux-amd64 into the container at
  the same absolute path. kandev's orchestrator builds the agent
  command from KANDEV_MOCK_AGENT_LINUX_BINARY (a host path), so the
  remote needs the binary at that exact path; bake-into-image isn't
  enough because the absolute host path is what kandev sends.
- Bind-mount /home/kandev/.kandev so per-session agentctl logs
  survive --rm teardown and the test runner can inspect them on
  failure.
- Replace the broken CPU-spin sleep helper with a real sleep
  subprocess and a /dev/tcp TCP-open probe so timing-dependent
  helpers stop racing the container start.
- Retry the host fingerprint scan with stderr capture; the first
  scan can race the sshd accept loop on Alpine.

Backend SSH executor (apps/backend/internal/agent/lifecycle):
- executor_ssh_operations.go startRemoteAgentctl: agentctl does not
  accept --port-file or --pid-file flags (it reads AGENTCTL_PORT
  and writes its own pid). Rewrite the launch wrapper to inject
  AGENTCTL_PORT via env, capture $! as the pid, and tail the
  on-remote agentctl.log for 'HTTP server bound successfully'
  instead of waiting on imaginary side-files.
- executor_ssh_operations.go createRemoteAgentInstance: new helper
  that POSTs /api/v1/instances on the in-container control server
  via SSH-exec'd curl, returning the per-instance port the executor
  should forward to. Mirrors what executor_sprites_operations.go
  does inside its sprite. Without this step the agent stream
  returns 'configure request failed with status 404' because the
  SSH executor was talking to the control server, not the
  per-session sub-server.
- executor_ssh.go startAndForwardAgentctl: chains the new
  create-instance step in between agentctl launch and port-forward,
  and forwards the *instance* port (not the control port).
- executor_ssh.go: drop the per-host SSH connection pool (it was
  introducing a subtle aliasing issue between
  CreateInstance/StopInstance/GetRemoteStatus that made the SSH
  client unreliable across same-host sessions). Each session now
  holds its own ssh.Client directly on sshSessionState and
  ResumeRemoteInstance dials a fresh client too.
- executor_ssh_operations.go SSHPortForwarder: serialize the
  client.Dial calls with a per-forwarder mutex. golang.org/x/crypto/
  ssh.Client.Dial is documented as concurrency-safe but in practice
  parallel opens from the kandev stream-manager occasionally
  produce io.EOF as if the channel-open response was never
  received.

Test fix (apps/web/e2e/tests/ssh/error-surfacing.spec.ts):
- Q1 ('TCP refused') was using identity_source='agent' with no
  SSH_AUTH_SOCK in the backend env, so it failed at
  buildAuthMethods before reaching the TCP-refused path. Switch to
  identity_source='file' with the seed key so the test exercises
  the failure it claims to.

Known remaining issue (to investigate next): the launch path now
reaches 'agent process started' + 'ACP initialize response
received' when run in isolation, but the WebSocket updates stream
sometimes disconnects with 1006 abnormal closure shortly after. A
standalone Go reproduction of concurrent direct-tcpip channels
against the same image works without issue, so the trigger is
something specific to the kandev backend's stream-manager + my
forwarder interaction. Tracked for the next iteration.
2026-05-17 23:45:07 +01:00
José Almeida 99404133d4 feat(backend): add SSH executor runtime
Run agents on any Linux box reachable over SSH: own VPS, homelab, EC2,
shared dev box. One SSH connection per (host, user, identity) shared
across all sessions on that host; each session gets its own remote
agentctl process, remote port, and SSH-tunneled local port. Mirrors the
local ~/.kandev/tasks/<task-dir>/<repo>/ layout on the remote so
multi-session tasks share a worktree and per-session runtime state lives
under the task dir.

Implements ExecutorBackend + RemoteSessionResumer + RemoteStatusProvider
+ Closeable. Host-key trust is explicit: the test endpoint observes a
fingerprint without pinning; the user trusts it in settings; subsequent
connects reject any mismatch. Auth via ssh-agent or IdentityFile only
(passphrase-protected keys must be loaded into ssh-agent). Parses
~/.ssh/config for HostName/Port/User/IdentityFile/ProxyJump inheritance.
agentctl is content-hash-cached on the remote (~/.kandev/bin/agentctl
plus a .sha256 sidecar) and uploaded only when local and remote differ.
Linux/amd64 only in v1, matching Docker's current state; arm64 is
called out as a cross-cutting follow-up.

See docs/specs/ssh-executor/spec.md.
2026-05-17 23:28:50 +01:00