fix(scanner): decouple port discovery from version detection
nmap -sV sends plaintext probes to TLS ports (e.g. Proxmox 8006). They stall until the host crosses --host-timeout, at which point nmap skips the whole host and discards ports it already found — a reachable host is returned with 0 open ports (issue #277). Split Phase 2 into two passes: Pass A (-sS/-sT --open) discovers ports fast with no version detection; its ports are authoritative. Pass B (-sV --host-timeout, scoped to the found ports) enriches banners best-effort — on timeout/failure the discovered ports are kept with empty banners instead of losing the host. Healthy hosts still get full-intensity -sV banners (no quality drop). Version host-timeout is now configurable via SCANNER_VERSION_HOST_TIMEOUT (default 60s). ha-relevant: yes
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Pouzor
@@ -14,6 +14,7 @@ from typing import Any
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from sqlalchemy import or_, select
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from sqlalchemy.ext.asyncio import AsyncSession
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from app.core.config import settings
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from app.db.models import Node, PendingDevice, ScanRun
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from app.services.discovery_sources import add_source
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from app.services.fingerprint import fingerprint_ports, suggest_node_type
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@@ -240,6 +241,14 @@ def _nmap_scan_single(host_dict: dict[str, Any], port_spec: str = _EXTRA_PORTS)
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"""
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Phase 2 — single-IP port scan with service detection.
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Runs in a thread (blocking). Returns the host dict enriched with open_ports.
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Two decoupled nmap passes (issue #277):
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Pass A — port discovery only (``--open``, no ``-sV``). Fast and reliable;
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its open ports are authoritative and are never discarded.
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Pass B — version detection (``-sV``) scoped to the ports Pass A found,
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bounded by ``--host-timeout``. Best-effort: if it times out or
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fails (e.g. a TLS port stalls plaintext probes), the Pass A ports
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are kept with empty banners instead of the whole host being lost.
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"""
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ip = host_dict["ip"]
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logger.info("[Phase 2] Scanning %s ...", ip)
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@@ -248,48 +257,76 @@ def _nmap_scan_single(host_dict: dict[str, Any], port_spec: str = _EXTRA_PORTS)
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logger.warning("[Phase 2] nmap not available, skipping %s", ip)
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return host_dict
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is_root = os.geteuid() == 0
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if is_root:
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# SYN scan + version detection (fastest, most accurate)
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scan_args = f"-sS -sV --open -T4 -Pn --host-timeout 60s -p {port_spec}"
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else:
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# TCP connect scan (-sT) — no raw sockets needed, works without root.
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# nmap auto-selects -sT without root but being explicit avoids edge cases.
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scan_args = f"-sT -sV --open -T4 -Pn --host-timeout 60s -p {port_spec}"
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# -sS (SYN) needs root; -sT (connect) works without it. nmap auto-selects
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# -sT without root but being explicit avoids edge cases.
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scan_type = "-sS" if os.geteuid() == 0 else "-sT"
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logger.debug("[Phase 2] %s args: %s", ip, scan_args)
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nm = nmap.PortScanner()
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# --- Pass A: port discovery (no -sV, no host-timeout) ---
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discovery_args = f"{scan_type} --open -T4 -Pn -p {port_spec}"
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logger.debug("[Phase 2] %s discovery args: %s", ip, discovery_args)
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nm_disc = nmap.PortScanner()
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try:
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nm.scan(hosts=ip, arguments=scan_args)
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nm_disc.scan(hosts=ip, arguments=discovery_args)
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except Exception as exc:
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logger.warning("[Phase 2] nmap FAILED for %s (%s: %s) — skipping port scan", ip, type(exc).__name__, exc)
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logger.warning("[Phase 2] nmap discovery FAILED for %s (%s: %s) — skipping port scan",
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ip, type(exc).__name__, exc)
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return host_dict
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all_scanned = nm.all_hosts()
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logger.debug("[Phase 2] %s — nmap returned %d host(s) in results", ip, len(all_scanned))
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if ip not in all_scanned:
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if ip not in nm_disc.all_hosts():
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logger.info("[Phase 2] %s — no open ports found (all closed/filtered or nmap had no results)", ip)
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return host_dict
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open_ports = []
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for proto in nm[ip].all_protocols():
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for port, info in nm[ip][proto].items():
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for proto in nm_disc[ip].all_protocols():
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for port, info in nm_disc[ip][proto].items():
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if info["state"] == "open":
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banner = (info.get("product", "") + " " + info.get("version", "")).strip()
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open_ports.append({"port": port, "protocol": proto, "banner": banner})
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open_ports.append({"port": port, "protocol": proto, "banner": ""})
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if open_ports:
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port_summary = ", ".join(
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f"{p['port']}/{p['protocol']} ({p['banner'] or 'unknown'})" for p in open_ports
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)
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logger.info("[Phase 2] %s — %d open port(s): %s", ip, len(open_ports), port_summary)
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else:
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if not open_ports:
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logger.info("[Phase 2] %s — 0 open ports detected", ip)
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host_dict["open_ports"] = []
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if not host_dict["mac"]:
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host_dict["mac"] = nm_disc[ip].get("addresses", {}).get("mac")
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return host_dict
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# --- Pass B: version detection on the discovered ports (best-effort) ---
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port_list = ",".join(str(p["port"]) for p in open_ports)
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timeout = settings.scanner_version_host_timeout
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version_args = f"{scan_type} -sV -T4 -Pn --host-timeout {timeout}s -p {port_list}"
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logger.debug("[Phase 2] %s version args: %s", ip, version_args)
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nm_ver = nmap.PortScanner()
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banners: dict[tuple[str, int], str] = {}
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ver_os = None
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ver_mac = None
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try:
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nm_ver.scan(hosts=ip, arguments=version_args)
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if ip in nm_ver.all_hosts():
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for proto in nm_ver[ip].all_protocols():
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for port, info in nm_ver[ip][proto].items():
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banner = (info.get("product", "") + " " + info.get("version", "")).strip()
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if banner:
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banners[(proto, port)] = banner
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ver_os = _extract_os(nm_ver, ip)
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ver_mac = nm_ver[ip].get("addresses", {}).get("mac")
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else:
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logger.info("[Phase 2] %s — version detection returned no results, keeping %d port(s) without banners",
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ip, len(open_ports))
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except Exception as exc:
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logger.info("[Phase 2] %s — version detection failed (%s: %s), keeping %d port(s) without banners",
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ip, type(exc).__name__, exc, len(open_ports))
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for p in open_ports:
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p["banner"] = banners.get((p["protocol"], p["port"]), "")
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port_summary = ", ".join(
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f"{p['port']}/{p['protocol']} ({p['banner'] or 'unknown'})" for p in open_ports
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)
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logger.info("[Phase 2] %s — %d open port(s): %s", ip, len(open_ports), port_summary)
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host_dict["open_ports"] = open_ports
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if not host_dict["mac"]:
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host_dict["mac"] = nm[ip].get("addresses", {}).get("mac")
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host_dict["os"] = _extract_os(nm, ip)
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host_dict["mac"] = ver_mac or nm_disc[ip].get("addresses", {}).get("mac")
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host_dict["os"] = ver_os
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return host_dict
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