fix: pin sish tunnel auth to the dedicated key with IdentitiesOnly - #551
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Without it, a forwarded ssh-agent (present when dev is re-run inside tmux after an SSH login) offers its keys before the -i file: sish's TOFU authenticator pins the first accepted key per username, so an agent key winning the first-ever connection silently locks the VM out of its tunnel once that agent disappears. Agent keys could also exhaust the SSH server's MaxAuthTries (6) before the tunnel key is offered. Found by a sish v2.23.0 source review of the auth webhook contract. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01ErBUiAYTosnpbF9hvUj3Dn
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One flag on the autossh invocation:
-o IdentitiesOnly=yes.A sish v2.23.0 source review of the tunnel auth flow found two failure modes when it's absent (both require a forwarded ssh-agent, which appears whenever
devis re-run from a tmux session after an SSH login — and everydevrun restarts autossh):-ifile identities. sish calls the TOFU authenticator once per offered key, and the first accepted key is pinned to the username forever. If an agent key wins the VM's first-ever connection, everything works until the agent disappears (detach/reboot → systemd path) — then every reconnect is akey mismatch403 and the tunnel is dead until the user's file insish_users/is deleted by hand.IdentitiesOnly=yesrestricts the client to exactly~/.ssh/sish_tunnel_key_id_ed25519, eliminating both. No behavior change for the systemd boot path (no agent there) — this hardens the interactive re-run path.🤖 Generated with Claude Code
https://claude.ai/code/session_01ErBUiAYTosnpbF9hvUj3Dn