57_WolveandClaude Opus 5
339c62a1b0
Proxmox VE and Proxmox Mail Gateway are Debian, so os_detect classified them as debian and harden-firewall.sh installed the iptables backend on top of pve-firewall. The conflict is not the obvious one. pve-firewall does NOT delete third-party rules: it restores with `iptables-restore -n` (--noflush), only ever flushes chains matching its own patterns (PVEFW-*, tapNiM-*, vethNiM-*, fwbrN-*, GROUP-*), appends `-A INPUT -j PVEFW-INPUT` only when that hook is missing, and never sets a built-in chain's policy. Our rules survive it. We are the ones doing damage: - `-P INPUT DROP` is ours alone, and PVEFW-HOST-IN RETURNs on accept rather than ACCEPTing (it still has to check tap rules), so traffic Proxmox explicitly allowed falls out of its chain onto our DROP -- we silently override the platform's own accepts. - netfilter-persistent restores at boot with a full iptables-restore (no --noflush), wiping PVE's hook along with everything else until the daemon re-appends it ~10s later. - a deny-by-default chain has to enumerate the whole platform to stay usable: 8006, 5405-5412/udp corosync, 60000-60050, 5900-5999, 3128, 22, 111/udp, plus Ceph when hyperconverged -- and `-i lo`, or pveproxy loses pvedaemon on :85. - under the nftables backend (PVE 8.2+) an nft DROP beats an iptables ACCEPT, so our rules would not even be authoritative. So don't manage a firewall there at all: - oslib: is_proxmox() -- matches hosts shipping pve-firewall (VE/PMG), not PBS. - harden-firewall.sh: a third backend, "pve", that deliberately does nothing. apply explains and exits 0, allow/deny refuse loudly rather than fake success for a rule they didn't add, list shows pve-firewall status. It overrides an explicit FW_BACKEND; FW_IGNORE_PVE=1 is the one escape hatch. - harden-ssh.sh / harden-jumphost.sh: skip the firewall and install the standalone INPUT -> sshguard boot hook instead. That jump is safe alongside pve-firewall -- inserted with -I, it sits ahead of the appended PVEFW-INPUT hook and keeps first look at NEW connections. Detection only helps hosts built from here on, so `disable` cleans up one that was hardened earlier: it detects leftovers (and says which signal fired), sets INPUT ACCEPT *before* flushing so it can't drop the SSH session it runs over, deletes /etc/firewall and the engine, disables boot restore and renames the saved rulesets aside rather than persisting the open state, re-adds the sshguard jump, and restarts pve-firewall. `apply` points at it when it spots leftovers. Documented plainly that skipped is NOT protected: Proxmox's firewall is off by default (cluster-wide enable defaults to 0, and the daemon tears its chains down every ~10s while it is), so these hosts have no host firewall until someone enables it -- and the node panel's "Firewall: Yes" is ignored while the datacenter one says No. Also: svc_disable + fw_restore_services/fw_saved_files in oslib (fw_enable_restore now derives from the former), and usage() prints the whole header block instead of a hardcoded line range. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
63 lines
2.8 KiB
YAML
63 lines
2.8 KiB
YAML
#cloud-config
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#
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# Jump-host (bastion) bootstrap -- Alpine, Debian, or Alma Linux.
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#
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# Same base steps as base.yml, but applies the bastion hardening
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# (scripts/harden-jumphost.sh) instead of plain SSH hardening:
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# - ssh-admins : full shell for maintenance
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# - ssh-jumpers : ProxyJump only, to the JUMP_TARGETS whitelist
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#
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# Fill in REPO_URL, HOST, and JUMP_TARGETS, then paste as instance user-data.
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# Add jumper/admin users afterwards with the installed `sshuser` tool.
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#
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# NOTE: harden-jumphost.sh prints a freshly generated root private key to
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# stdout (-> the cloud console/serial log). Capture it there, or rely on the
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# keys seeded from globals/ and ignore it.
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runcmd:
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- |
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set -e
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# ===== config =====
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REPO_URL=https://git.anomalous.dev/57_Wolve/automations.git
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REPO_BRANCH=main
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HOST=ssh-1 # <svc>-<n>; "ssh" is the bastion service code
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BASE_DOMAIN=srvno.de
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DATACENTER="Globally Everywhere"
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SSH_PORT=22
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ALLOWED_IP= # optional: whitelist your client IP
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ENABLE_FIREWALL=1 # deny-by-default host firewall (0 to skip;
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# always skipped on Proxmox -- pve-firewall owns it)
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JUMP_TARGETS="10.0.0.5:22 10.0.0.6:22" # hosts jumpers may ProxyJump to
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# Optional login notifications (pam_exec -> ntfy). Leave NTFY_URL empty to
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# skip. NTFY_REGION defaults to the region segment of this host's FQDN.
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NTFY_URL=
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NTFY_TOKEN= # bearer token; empty if unauth publish
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NTFY_EMAIL=
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NTFY_REGION=
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# ==================
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# Prerequisites (OS-agnostic).
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if command -v apk >/dev/null 2>&1; then apk add --no-cache bash git curl
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elif command -v apt-get >/dev/null 2>&1; then apt-get update -qq && apt-get install -y -qq bash git curl
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elif command -v dnf >/dev/null 2>&1; then dnf install -y -q bash git curl
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fi
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git clone --depth 1 --branch "$REPO_BRANCH" "$REPO_URL" /opt/automations
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cd /opt/automations
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# Hostname + shared MOTD.
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HOST="$HOST" BASE_DOMAIN="$BASE_DOMAIN" DATACENTER="$DATACENTER" bash scripts/setup-host.sh
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# Seed root's (ssh-admins) authorized_keys from globals/.
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. scripts/lib.sh && load_globals \
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&& install -d -m 700 /root/.ssh \
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&& resolve_ssh_keys >> /root/.ssh/authorized_keys || true
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sort -u /root/.ssh/authorized_keys -o /root/.ssh/authorized_keys 2>/dev/null || true
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# Bastion hardening (admins shell + jumpers ProxyJump whitelist + optional
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# login notifications).
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SSH_PORT="$SSH_PORT" ALLOWED_IP="$ALLOWED_IP" JUMP_TARGETS="$JUMP_TARGETS" \
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ENABLE_FIREWALL="$ENABLE_FIREWALL" \
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NTFY_URL="$NTFY_URL" NTFY_TOKEN="$NTFY_TOKEN" NTFY_EMAIL="$NTFY_EMAIL" NTFY_REGION="$NTFY_REGION" \
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FORCE=1 bash scripts/harden-jumphost.sh
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