Verify SSH host keys against known_hosts - #396
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ssh2 accepts any host key when no hostVerifier is set, so the Console completed the handshake with whatever answered the address and handed it the user's credentials and forwarded agent. Read the known_hosts files `ssh -G` resolves for the host, pin the key on first use, and refuse to connect when a pinned key changes. Honours StrictHostKeyChecking, UserKnownHostsFile, GlobalKnownHostsFile and HashKnownHosts.
jameshoweee
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amaudruz and
christian-mcdermott
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September 8, 2026 17:27
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ssh2 accepts any host key when no
hostVerifieris set, and the Console never sets one. So a remote connection completes against whatever answers on the address and hands it the user's password or private key, plus the forwarded agent socket when agent forwarding is on. There is no host-key check today at all.This adds one. It reads the same known_hosts files OpenSSH would use for that host (resolved from
ssh -G, so aliases andUserKnownHostsFile/GlobalKnownHostsFileare honoured), matches plain, hashed, glob and negated patterns, honours@revoked, pins the key on first use, and refuses when a pinned key changes.StrictHostKeyCheckingis respected:yesrefuses an unknown host, anything else accepts and records it. A changed key is refused under every setting. An unreadable known_hosts fails closed rather than turning into blind trust.@cert-authoritylines are reported as unknown rather than as a match. This does not validate host certificates, and ssh2 never advertises the*-cert-v01@openssh.comalgorithms, so a server cannot present one on this path anyway.Tests: 44 new cases over the parser, the matcher and the verifier, plus an end-to-end case proving the resolved ConnectConfig refuses a changed key, and one against a real known_hosts file on disk. 153/153 in the ssh suite, 3100/3101 across the node project (the one failure is session-spawner, which fails the same way on main).