fix(ssh): forbid password authentication fallback - #1120
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Clever Cloud SSH only accepts key auth. Disable password fallback so a missing or unregistered key fails fast instead of prompting for a password that cannot work. Pass PreferredAuthentications=publickey and PasswordAuthentication=no to the ssh client. Fixes CleverCloud#574
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Summary
Clever Cloud SSH only accepts key authentication. When a key is missing or not registered,
clever sshused to fall back to a password prompt that can never succeed.This disables password authentication for the SSH session so the failure is immediate and clearer for users and support.
Fixes #574
Change
Pass to the ssh client:
PreferredAuthentications=publickeyPasswordAuthentication=noTest plan
clever sshwith a valid key still connectsclever sshwith a missing/unregistered key fails without asking for a passwordE2E results (2026-08-13)
Tested against a real Clever Cloud Node app with the patched CLI (
clever-toolsPR checkout, linked as localclever).clever ssh-keys add, then:SSH_AUTH_SOCK= clever ssh -a <app> -i <good> -c 'echo SSH_OK'→
SSH_OK, exit 0SSH_AUTH_SOCK= clever ssh -a <app> -i <bad> -c 'echo SSH_OK'→ exit 255 in under 1s, no password prompt
Note: without clearing the agent, OpenSSH may still offer other loaded keys, so a wrong
-ican succeed if another registered key is available in the agent. That is normal OpenSSH behavior and unrelated to this change. For a clean negative test, useSSH_AUTH_SOCK=(orIdentitiesOnly=yeson a rawsshcall).Test app and temporary SSH key were deleted after the run.