merge: testing → main (reconcile 2-week divergence)

decnet/templates/pop3/Dockerfile

@@ -0,0 +1,23 @@
+ARG BASE_IMAGE=debian:bookworm-slim
+FROM ${BASE_IMAGE}
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    python3 \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY syslog_bridge.py /opt/syslog_bridge.py
+COPY server.py /opt/server.py
+COPY entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+EXPOSE 110 995
+RUN useradd -r -s /bin/false -d /opt logrelay \
+ && apt-get update && apt-get install -y --no-install-recommends libcap2-bin \
+ && rm -rf /var/lib/apt/lists/* \
+ && (find /usr/bin/ -maxdepth 1 -name 'python3*' -type f -exec setcap 'cap_net_bind_service+eip' {} \; 2>/dev/null || true)
+
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
+  CMD kill -0 1 || exit 1
+
+USER logrelay
+ENTRYPOINT ["/entrypoint.sh"]

decnet/templates/pop3/entrypoint.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+set -e
+exec python3 /opt/server.py

decnet/templates/pop3/instance_seed.py

@@ -0,0 +1,120 @@
+#!/usr/bin/env python3
+"""
+Per-instance stealth seeding for honeypot service templates.
+
+The whole decoy fleet looks identical to a scanner unless each decky
+diverges on the boring details: cluster UUIDs, auth salts, uptime, minor
+version strings, etc. This module derives a stable per-instance seed
+from NODE_NAME (+ optional INSTANCE_ID) and exposes helpers that return
+deterministic-per-decky-but-different-across-the-fleet values.
+
+Connection-time jitter is intentionally NOT seeded — two hits to the same
+decky should not replay the same latency curve.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import hashlib
+import os
+import random
+import time
+import uuid
+from typing import Sequence, TypeVar
+
+T = TypeVar("T")
+
+_HOSTNAME = (
+    os.environ.get("NODE_NAME")
+    or os.environ.get("HOSTNAME")
+    or "decky"
+)
+_INSTANCE_ID = os.environ.get("INSTANCE_ID", "")
+_SEED_MATERIAL = f"{_HOSTNAME}:{_INSTANCE_ID}".encode()
+_SEED_INT = int.from_bytes(hashlib.sha256(_SEED_MATERIAL).digest()[:8], "big")
+
+#: Deterministic RNG seeded per decky — use for *persistent* choices
+#: (versions, UUIDs, stored credentials). Never use for timing.
+rng = random.Random(_SEED_INT)
+
+#: Process boot time — real uptime elapsed since container start.
+_PROCESS_START = time.time()
+
+#: Deterministic per-instance fake "has been up for this long at boot"
+#: offset, so every decky pretends to have a different history.
+_BOOT_OFFSET = rng.randint(3600, 45 * 86400)
+
+
+def hostname() -> str:
+    return _HOSTNAME
+
+
+def uptime_seconds() -> int:
+    """Monotonically increasing, unique per instance."""
+    return int(_BOOT_OFFSET + (time.time() - _PROCESS_START))
+
+
+def boot_epoch() -> int:
+    """Fake wall-clock boot time for this instance (seconds since epoch)."""
+    return int(time.time() - uptime_seconds())
+
+
+def instance_uuid(namespace: str = "") -> str:
+    """Deterministic UUID4-looking value for this instance+namespace."""
+    ns = uuid.UUID("00000000-0000-0000-0000-000000000000")
+    return str(uuid.uuid5(ns, f"{_HOSTNAME}:{namespace}"))
+
+
+def instance_hex(nbytes: int, namespace: str = "") -> str:
+    """Deterministic hex token of given byte length."""
+    material = f"{_HOSTNAME}:{namespace}".encode()
+    digest = hashlib.sha256(material).digest()
+    while len(digest) < nbytes:
+        digest += hashlib.sha256(digest).digest()
+    return digest[:nbytes].hex()
+
+
+def pick(choices: Sequence[T]) -> T:
+    """Deterministic choice from a sequence."""
+    return rng.choice(list(choices))
+
+
+def pick_weighted(choices: Sequence[tuple[T, float]]) -> T:
+    """Deterministic weighted choice. Input: [(item, weight), ...]."""
+    total = sum(w for _, w in choices)
+    r = rng.uniform(0, total)
+    acc = 0.0
+    for item, w in choices:
+        acc += w
+        if r <= acc:
+            return item
+    return choices[-1][0]
+
+
+def random_bytes(n: int, namespace: str = "") -> bytes:
+    """Deterministic per-instance byte string of length n."""
+    out = bytearray()
+    i = 0
+    while len(out) < n:
+        out.extend(
+            hashlib.sha256(f"{_HOSTNAME}:{namespace}:{i}".encode()).digest()
+        )
+        i += 1
+    return bytes(out[:n])
+
+
+def fresh_bytes(n: int) -> bytes:
+    """Non-deterministic random bytes — for per-connection nonces/salts."""
+    return os.urandom(n)
+
+
+async def jitter(min_ms: int = 5, max_ms: int = 120) -> None:
+    """Async response-time jitter. Uses unseeded RNG so timing varies
+    across connections to the same decky — seeded jitter would leak
+    predictability."""
+    await asyncio.sleep(random.uniform(min_ms, max_ms) / 1000.0)
+
+
+def jitter_sync(min_ms: int = 5, max_ms: int = 120) -> None:
+    """Blocking jitter for non-asyncio servers."""
+    time.sleep(random.uniform(min_ms, max_ms) / 1000.0)

decnet/templates/pop3/server.py

@@ -0,0 +1,488 @@
+#!/usr/bin/env python3
+"""
+POP3 server (port 110).
+Full POP3 state machine with bait mailbox.
+
+States: AUTHORIZATION → TRANSACTION
+
+Credentials via IMAP_USERS env var (shared with IMAP service).
+10 bait emails containing AWS keys, DB passwords, tokens etc.
+"""
+
+import asyncio
+import os
+import time
+from pathlib import Path
+from syslog_bridge import (
+    SEVERITY_WARNING,
+    encode_secret,
+    forward_syslog,
+    syslog_line,
+    write_syslog_file,
+)
+
+NODE_NAME    = os.environ.get("NODE_NAME", "mailserver")
+SERVICE_NAME  = "pop3"
+LOG_TARGET   = os.environ.get("LOG_TARGET", "")
+PORT         = int(os.environ.get("PORT", "110"))
+POP3_BANNER  = os.environ.get("POP3_BANNER", f"+OK {NODE_NAME} Dovecot POP3 ready.")
+_RAW_USERS   = os.environ.get("IMAP_USERS", "admin:admin123,root:toor,mail:mail,user:user")
+
+VALID_USERS: dict[str, str] = {
+    u: p for part in _RAW_USERS.split(",") if ":" in part for u, p in [part.split(":", 1)]
+}
+
+# Path to a directory of ``*.eml`` files dropped by the orchestrator
+# emailgen worker (``/var/spool/decnet-emails/`` by convention).  When
+# set and populated, those EMLs replace the hardcoded fallback list
+# below — same semantics as the IMAP template.  Empty / missing falls
+# back so a fresh deployment is never silent.
+_EMAIL_SEED_PATH = os.environ.get("POP3_EMAIL_SEED", "")
+_SEED_RESCAN_INTERVAL = float(os.environ.get("POP3_EMAIL_SEED_RESCAN", "5"))
+
+# ── Bait emails ───────────────────────────────────────────────────────────────
+
+_BAIT_EMAILS: list[str] = [
+    (
+        "Date: Mon, 06 Nov 2023 09:12:33 +0000\r\n"
+        "From: DevOps Team <devops@company.internal>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: AWS credentials rotation\r\n"
+        "Message-ID: <1@company.internal>\r\n"
+        "\r\n"
+        "Team,\r\n\r\n"
+        "New AWS credentials have been issued. Old keys deactivated.\r\n\r\n"
+        "Access Key ID:     AKIAIOSFODNN7EXAMPLE\r\n"
+        "Secret Access Key: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY\r\n\r\n"
+        "Update ~/.aws/credentials immediately.\r\n\r\n-- DevOps\r\n"
+    ),
+    (
+        "Date: Tue, 07 Nov 2023 14:05:11 +0000\r\n"
+        "From: Monitoring <monitoring@company.internal>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: DB password changed\r\n"
+        "Message-ID: <2@company.internal>\r\n"
+        "\r\n"
+        "Production database password was rotated.\r\n\r\n"
+        "Connection string: mysql://admin:Sup3rS3cr3t!@10.0.1.5:3306/production\r\n\r\n"
+        "Update all app configs.\r\n"
+    ),
+    (
+        "Date: Wed, 08 Nov 2023 08:30:00 +0000\r\n"
+        "From: GitHub <noreply@github.com>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: Your personal access token\r\n"
+        "Message-ID: <3@company.internal>\r\n"
+        "\r\n"
+        "Hi admin,\r\n\r\n"
+        "A new personal access token was created for your account.\r\n\r\n"
+        "Token: ghp_16C7e42F292c6912E7710c838347Ae178B4a\r\n\r\n"
+        "If this wasn't you, revoke it immediately at github.com/settings/tokens.\r\n"
+    ),
+    (
+        "Date: Thu, 09 Nov 2023 11:22:47 +0000\r\n"
+        "From: IT Admin <admin@company.internal>\r\n"
+        "To: team@company.internal\r\n"
+        "Subject: VPN config attached\r\n"
+        "Message-ID: <4@company.internal>\r\n"
+        "\r\n"
+        "VPN access details for new starters:\r\n\r\n"
+        "  Host:     vpn.company.internal:1194\r\n"
+        "  Protocol: UDP\r\n"
+        "  Username: vpnadmin\r\n"
+        "  Password: VpnP@ss2024\r\n\r\n"
+        "Config file sent separately via secure channel.\r\n"
+    ),
+    (
+        "Date: Fri, 10 Nov 2023 16:45:00 +0000\r\n"
+        "From: SysAdmin <sysadmin@company.internal>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: Root password\r\n"
+        "Message-ID: <5@company.internal>\r\n"
+        "\r\n"
+        "New root password for prod servers:\r\n\r\n"
+        "  r00tM3T00!\r\n\r\n"
+        "Change after first login. Do NOT forward this email.\r\n"
+    ),
+    (
+        "Date: Sat, 11 Nov 2023 03:12:04 +0000\r\n"
+        "From: Backup System <backup@company.internal>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: Backup job failed\r\n"
+        "Message-ID: <6@company.internal>\r\n"
+        "\r\n"
+        "Nightly backup to 192.168.1.50:/mnt/nas FAILED at 03:11 UTC.\r\n\r\n"
+        "Error: Authentication failed. Credentials in /etc/backup.conf may be stale.\r\n\r\n"
+        "Last successful backup: 2023-11-10 03:11 UTC\r\n"
+    ),
+    (
+        "Date: Sun, 12 Nov 2023 07:04:31 +0000\r\n"
+        "From: Security Alerts <alerts@company.internal>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: SSH brute-force alert\r\n"
+        "Message-ID: <7@company.internal>\r\n"
+        "\r\n"
+        "47 failed SSH login attempts detected against prod-web-01.\r\n\r\n"
+        "Source IPs: 185.220.101.34, 185.220.101.47, 185.220.101.52\r\n"
+        "Target user: root\r\n"
+        "Period: 2023-11-12 06:58 - 07:04 UTC\r\n\r\n"
+        "All attempts blocked by fail2ban. No successful logins.\r\n"
+    ),
+    (
+        "Date: Mon, 13 Nov 2023 10:11:55 +0000\r\n"
+        "From: External Vendor <vendor@external.com>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: RE: API integration\r\n"
+        "Message-ID: <8@company.internal>\r\n"
+        "\r\n"
+        "Hi,\r\n\r\n"
+        "Here is the live API key for the integration:\r\n\r\n"
+        "  sk_live_9mK3xF2aP7qR1bN8cT4dW6vE0yU5hJ\r\n\r\n"
+        "Keep this confidential. Let me know if you need the webhook secret.\r\n\r\n"
+        "Best regards,\r\nVendor Support\r\n"
+    ),
+    (
+        "Date: Tue, 14 Nov 2023 13:48:22 +0000\r\n"
+        "From: Help Desk <helpdesk@company.internal>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: Password reset request\r\n"
+        "Message-ID: <9@company.internal>\r\n"
+        "\r\n"
+        "Hi,\r\n\r\n"
+        "Could you reset my MFA? Current password is Winter2024! so you can verify it's me.\r\n\r\n"
+        "Thanks\r\n"
+    ),
+    (
+        "Date: Wed, 15 Nov 2023 00:01:00 +0000\r\n"
+        "From: AWS Billing <noreply@aws.amazon.com>\r\n"
+        "To: admin@company.internal\r\n"
+        "Subject: Your AWS bill is ready\r\n"
+        "Message-ID: <10@company.internal>\r\n"
+        "\r\n"
+        "Your AWS bill for October 2023 is $847.23.\r\n\r\n"
+        "Top services:\r\n"
+        "  EC2 (us-east-1):   $412.10\r\n"
+        "  RDS (us-east-1):   $198.50\r\n"
+        "  S3:                 $87.43\r\n"
+        "  EC2 (eu-west-2):   $149.20\r\n\r\n"
+        "Account ID: 123456789012\r\n"
+    ),
+]
+
+
+# ── Spool-backed email loader ─────────────────────────────────────────────────
+# POP3 stores each message as a single str (full RFC 822 text); when the
+# emailgen spool is configured, we read every *.eml in it and serve the
+# raw bytes as the corpus.  Same caching strategy as the IMAP template.
+
+_seed_cache: list[str] | None = None
+_seed_cache_dir_mtime: float = 0.0
+_seed_cache_loaded_at: float = 0.0
+
+
+def _scan_seed_dir(path: Path) -> list[str]:
+    """Walk *path* recursively and return each .eml's raw text content,
+    sorted by mtime so older threads get lower indices."""
+    eml_paths: list[Path] = []
+    try:
+        for p in path.rglob("*.eml"):
+            if p.is_file():
+                eml_paths.append(p)
+    except OSError:
+        return []
+    eml_paths.sort(key=lambda p: p.stat().st_mtime)
+    out: list[str] = []
+    for p in eml_paths:
+        try:
+            out.append(p.read_text(encoding="utf-8", errors="replace"))
+        except OSError:
+            continue
+    return out
+
+
+def _get_emails() -> list[str]:
+    """Return the active corpus.  Same fallback rules as IMAP template."""
+    global _seed_cache, _seed_cache_dir_mtime, _seed_cache_loaded_at
+    if not _EMAIL_SEED_PATH:
+        return _BAIT_EMAILS
+    seed_dir = Path(_EMAIL_SEED_PATH)
+    try:
+        dir_stat = seed_dir.stat()
+    except OSError:
+        return _BAIT_EMAILS
+    now = time.monotonic()
+    fresh_enough = (
+        _seed_cache is not None
+        and (now - _seed_cache_loaded_at) < _SEED_RESCAN_INTERVAL
+        and dir_stat.st_mtime == _seed_cache_dir_mtime
+    )
+    if fresh_enough:
+        return _seed_cache or _BAIT_EMAILS
+    scanned = _scan_seed_dir(seed_dir)
+    if not scanned:
+        return _BAIT_EMAILS
+    _seed_cache = scanned
+    _seed_cache_dir_mtime = dir_stat.st_mtime
+    _seed_cache_loaded_at = now
+    return scanned
+
+
+# ── Logging ───────────────────────────────────────────────────────────────────
+
+def _log(event_type: str, severity: int = 6, **kwargs) -> None:
+    line = syslog_line(SERVICE_NAME, NODE_NAME, event_type, severity, **kwargs)
+    write_syslog_file(line)
+    forward_syslog(line, LOG_TARGET)
+
+
+# ── Protocol ──────────────────────────────────────────────────────────────────
+
+class POP3Protocol(asyncio.Protocol):
+    def __init__(self):
+        self._transport    = None
+        self._peer         = ("?", 0)
+        self._buf          = b""
+        self._state        = "AUTHORIZATION"
+        self._current_user: str | None = None
+        self._deleted: set[int] = set()   # 0-based indices of DELE'd messages
+
+    def connection_made(self, transport):
+        self._transport = transport
+        self._peer = transport.get_extra_info("peername", ("?", 0))
+        _log("connect", src=self._peer[0], src_port=self._peer[1])
+        banner = POP3_BANNER if POP3_BANNER.endswith("\r\n") else POP3_BANNER + "\r\n"
+        if not banner.startswith("+OK"):
+            banner = "+OK " + banner
+        transport.write(banner.encode())
+
+    def data_received(self, data):
+        self._buf += data
+        while b"\n" in self._buf:
+            line, self._buf = self._buf.split(b"\n", 1)
+            self._handle_line(line.decode(errors="replace").strip())
+
+    def connection_lost(self, exc):
+        _log("disconnect", src=self._peer[0] if self._peer else "?")
+
+    # ── Command dispatch ──────────────────────────────────────────────────────
+
+    def _handle_line(self, line: str) -> None:
+        parts = line.split(None, 1)
+        if not parts:
+            return
+        cmd  = parts[0].upper()
+        args = parts[1] if len(parts) > 1 else ""
+
+        _log("command", src=self._peer[0], cmd=cmd, state=self._state)
+
+        # Always available
+        if cmd == "CAPA":
+            self._transport.write(
+                b"+OK\r\nTOP\r\nUSER\r\nUIDL\r\nRESP-CODES\r\nAUTH-RESP-CODE\r\nSASL\r\n.\r\n"
+            )
+        elif cmd == "QUIT":
+            self._transport.write(b"+OK Logging out.\r\n")
+            self._transport.close()
+
+        # AUTHORIZATION state
+        elif cmd == "USER":
+            self._cmd_user(args)
+        elif cmd == "PASS":
+            self._cmd_pass(args)
+
+        # TRANSACTION state
+        elif cmd == "STAT":
+            self._cmd_stat()
+        elif cmd == "LIST":
+            self._cmd_list(args)
+        elif cmd == "RETR":
+            self._cmd_retr(args)
+        elif cmd == "TOP":
+            self._cmd_top(args)
+        elif cmd == "UIDL":
+            self._cmd_uidl(args)
+        elif cmd == "DELE":
+            self._cmd_dele(args)
+        elif cmd == "RSET":
+            self._cmd_rset()
+        elif cmd == "NOOP":
+            self._transport.write(b"+OK\r\n")
+
+        else:
+            self._transport.write(b"-ERR Command not recognized\r\n")
+
+    # ── Command implementations ───────────────────────────────────────────────
+
+    def _cmd_user(self, args: str) -> None:
+        if self._state != "AUTHORIZATION":
+            self._transport.write(b"-ERR Already authenticated\r\n")
+            return
+        self._current_user = args.strip()
+        self._transport.write(b"+OK User name accepted, password please\r\n")
+
+    def _cmd_pass(self, args: str) -> None:
+        if self._state != "AUTHORIZATION":
+            self._transport.write(b"-ERR Already authenticated\r\n")
+            return
+        if not self._current_user:
+            self._transport.write(b"-ERR USER required first\r\n")
+            return
+        username = self._current_user
+        password = args.strip()
+        _enc = encode_secret(password)
+        if VALID_USERS.get(username) == password:
+            self._state = "TRANSACTION"
+            _log("auth", src=self._peer[0], username=username, principal=username,
+                 outcome="success", **_enc)
+            self._transport.write(b"+OK Logged in.\r\n")
+        else:
+            _log("auth", src=self._peer[0], username=username, principal=username,
+                 outcome="failure", severity=SEVERITY_WARNING, **_enc)
+            self._current_user = None
+            self._transport.write(b"-ERR Authentication failed.\r\n")
+
+    def _require_transaction(self) -> bool:
+        if self._state != "TRANSACTION":
+            self._transport.write(b"-ERR Not authenticated\r\n")
+            return False
+        return True
+
+    def _active_messages(self) -> list[tuple[int, str]]:
+        """Return [(1-based-num, body), ...] excluding DELE'd messages."""
+        return [
+            (i + 1, body)
+            for i, body in enumerate(_get_emails())
+            if i not in self._deleted
+        ]
+
+    def _cmd_stat(self) -> None:
+        if not self._require_transaction():
+            return
+        msgs = self._active_messages()
+        total = sum(len(b.encode()) for _, b in msgs)
+        self._transport.write(f"+OK {len(msgs)} {total}\r\n".encode())
+
+    def _cmd_list(self, args: str) -> None:
+        if not self._require_transaction():
+            return
+        emails = _get_emails()
+        if args:
+            try:
+                n = int(args)
+                idx = n - 1
+                if idx in self._deleted or not (0 <= idx < len(emails)):
+                    self._transport.write(b"-ERR No such message\r\n")
+                else:
+                    size = len(emails[idx].encode())
+                    self._transport.write(f"+OK {n} {size}\r\n".encode())
+            except ValueError:
+                self._transport.write(b"-ERR Invalid argument\r\n")
+        else:
+            msgs  = self._active_messages()
+            total = sum(len(b.encode()) for _, b in msgs)
+            self._transport.write(f"+OK {len(msgs)} messages ({total} octets)\r\n".encode())
+            for n, body in msgs:
+                self._transport.write(f"{n} {len(body.encode())}\r\n".encode())
+            self._transport.write(b".\r\n")
+
+    def _cmd_retr(self, args: str) -> None:
+        if not self._require_transaction():
+            return
+        try:
+            n   = int(args)
+            idx = n - 1
+            emails = _get_emails()
+            if idx in self._deleted or not (0 <= idx < len(emails)):
+                self._transport.write(b"-ERR No such message\r\n")
+                return
+            body = emails[idx]
+            raw  = body.encode()
+            _log("retr", src=self._peer[0], message_num=n)
+            self._transport.write(f"+OK {len(raw)} octets\r\n".encode())
+            self._transport.write(raw)
+            if not raw.endswith(b"\r\n"):
+                self._transport.write(b"\r\n")
+            self._transport.write(b".\r\n")
+        except ValueError:
+            self._transport.write(b"-ERR Invalid argument\r\n")
+
+    def _cmd_top(self, args: str) -> None:
+        if not self._require_transaction():
+            return
+        try:
+            parts     = args.split(None, 1)
+            n         = int(parts[0])
+            line_count = int(parts[1]) if len(parts) > 1 else 0
+            idx = n - 1
+            emails = _get_emails()
+            if idx in self._deleted or not (0 <= idx < len(emails)):
+                self._transport.write(b"-ERR No such message\r\n")
+                return
+            body    = emails[idx]
+            sep     = "\r\n\r\n"
+            if sep in body:
+                headers, rest = body.split(sep, 1)
+                headers += sep
+            else:
+                headers, rest = body, ""
+            body_lines = rest.split("\r\n")[:line_count]
+            result     = headers + "\r\n".join(body_lines)
+            self._transport.write(b"+OK\r\n")
+            self._transport.write(result.encode())
+            if not result.endswith("\r\n"):
+                self._transport.write(b"\r\n")
+            self._transport.write(b".\r\n")
+        except (ValueError, IndexError):
+            self._transport.write(b"-ERR Invalid arguments\r\n")
+
+    def _cmd_uidl(self, args: str) -> None:
+        if not self._require_transaction():
+            return
+        if args:
+            try:
+                n   = int(args)
+                idx = n - 1
+                if idx in self._deleted or not (0 <= idx < len(_get_emails())):
+                    self._transport.write(b"-ERR No such message\r\n")
+                else:
+                    self._transport.write(f"+OK {n} msg-{n}\r\n".encode())
+            except ValueError:
+                self._transport.write(b"-ERR Invalid argument\r\n")
+        else:
+            self._transport.write(b"+OK\r\n")
+            for n, _ in self._active_messages():
+                self._transport.write(f"{n} msg-{n}\r\n".encode())
+            self._transport.write(b".\r\n")
+
+    def _cmd_dele(self, args: str) -> None:
+        if not self._require_transaction():
+            return
+        try:
+            n   = int(args)
+            idx = n - 1
+            if idx in self._deleted or not (0 <= idx < len(_get_emails())):
+                self._transport.write(b"-ERR No such message\r\n")
+            else:
+                self._deleted.add(idx)
+                _log("delete", src=self._peer[0], message_num=n)
+                self._transport.write(f"+OK Message {n} deleted\r\n".encode())
+        except ValueError:
+            self._transport.write(b"-ERR Invalid argument\r\n")
+
+    def _cmd_rset(self) -> None:
+        if not self._require_transaction():
+            return
+        self._deleted.clear()
+        self._transport.write(b"+OK\r\n")
+
+
+async def main():
+    _log("startup", msg=f"POP3 server starting as {NODE_NAME}")
+    loop = asyncio.get_running_loop()
+    server = await loop.create_server(POP3Protocol, "0.0.0.0", PORT)  # nosec B104
+    async with server:
+        await server.serve_forever()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())

decnet/templates/pop3/syslog_bridge.py

@@ -0,0 +1,261 @@
+#!/usr/bin/env python3
+"""
+Shared RFC 5424 syslog helper used by service containers.
+
+Services call syslog_line() to format an RFC 5424 message, then
+write_syslog_file() to emit it to stdout — the container runtime
+captures it, and the host-side collector streams it into the log file.
+
+RFC 5424 structure:
+  <PRI>1 TIMESTAMP HOSTNAME APP-NAME PROCID MSGID [SD-ELEMENT] MSG
+
+Facility: local0 (16). SD element ID uses PEN 55555.
+"""
+
+import base64
+import re
+from datetime import datetime, timezone
+from typing import Any, Optional
+
+# ─── Constants ────────────────────────────────────────────────────────────────
+
+_FACILITY_LOCAL0 = 16
+_SD_ID = "relay@55555"
+_NILVALUE = "-"
+
+SEVERITY_EMERG   = 0
+SEVERITY_ALERT   = 1
+SEVERITY_CRIT    = 2
+SEVERITY_ERROR   = 3
+SEVERITY_WARNING = 4
+SEVERITY_NOTICE  = 5
+SEVERITY_INFO    = 6
+SEVERITY_DEBUG   = 7
+
+_MAX_HOSTNAME = 255
+_MAX_APPNAME  = 48
+_MAX_MSGID    = 32
+
+# ─── Formatter ────────────────────────────────────────────────────────────────
+
+def _sd_escape(value: str) -> str:
+    """Escape SD-PARAM-VALUE per RFC 5424 §6.3.3."""
+    return value.replace("\\", "\\\\").replace('"', '\\"').replace("]", "\\]")
+
+
+def _sd_element(fields: dict[str, Any]) -> str:
+    if not fields:
+        return _NILVALUE
+    params = " ".join(f'{k}="{_sd_escape(str(v))}"' for k, v in fields.items())
+    return f"[{_SD_ID} {params}]"
+
+
+def syslog_line(
+    service: str,
+    hostname: str,
+    event_type: str,
+    severity: int = SEVERITY_INFO,
+    timestamp: datetime | None = None,
+    msg: str | None = None,
+    **fields: Any,
+) -> str:
+    """
+    Return a single RFC 5424-compliant syslog line (no trailing newline).
+
+    Args:
+        service:    APP-NAME (e.g. "http", "mysql")
+        hostname:   HOSTNAME (node name)
+        event_type: MSGID    (e.g. "request", "login_attempt")
+        severity:   Syslog severity integer (default: INFO=6)
+        timestamp:  UTC datetime; defaults to now
+        msg:        Optional free-text MSG
+        **fields:   Encoded as structured data params
+    """
+    pri     = f"<{_FACILITY_LOCAL0 * 8 + severity}>"
+    ts      = (timestamp or datetime.now(timezone.utc)).isoformat()
+    host    = (hostname or _NILVALUE)[:_MAX_HOSTNAME]
+    appname = (service  or _NILVALUE)[:_MAX_APPNAME]
+    msgid   = (event_type or _NILVALUE)[:_MAX_MSGID]
+    sd      = _sd_element(fields)
+    message = f" {msg}" if msg else ""
+    return f"{pri}1 {ts} {host} {appname} {_NILVALUE} {msgid} {sd}{message}"
+
+
+def encode_secret(secret: str) -> dict[str, str]:
+    """Standardized credential-secret encoding for the universal SD-block shape.
+
+    Returns ``{'secret_printable': ..., 'secret_b64': ...}`` ready to spread
+    into a :func:`syslog_line` / ``_log`` call::
+
+        _log("auth_attempt", principal=user, **encode_secret(password))
+
+    ``secret_printable`` mirrors auth-helper.c's sd_escape: bytes outside
+    ``[0x20, 0x7f)`` collapse to ``'?'`` so the field is always parser-safe
+    RFC 5424 ASCII. ``secret_b64`` preserves the *original* utf-8 bytes —
+    NUL/0xff/control/non-utf8 sequences all survive losslessly, useful as
+    a fingerprinting signal even when the printable form sanitizes them.
+
+    The decnet web ingester's native-shape branch keys off ``secret_b64``
+    being present, so any service emitter calling this helper lands its
+    cred attempt directly in the :class:`Credential` table.
+    """
+    raw = secret.encode("utf-8", errors="replace")
+    printable = "".join(chr(b) if 0x20 <= b < 0x7f else "?" for b in raw)
+    return {
+        "secret_printable": printable,
+        "secret_b64": base64.b64encode(raw).decode("ascii"),
+    }
+
+
+_DIGEST_PARAM_RE = re.compile(r'(\w+)\s*=\s*"([^"]*)"|(\w+)\s*=\s*([^,\s]+)')
+
+
+def classify_authorization(header_value: Optional[str]) -> Optional[dict[str, Any]]:
+    """Parse an HTTP Authorization header value into Credential SD fields.
+
+    Returns a dict with the universal cred shape ready to spread into a
+    ``_log(...)`` call::
+
+        auth = request.headers.get("Authorization")
+        cred = classify_authorization(auth)
+        if cred:
+            _log("auth_attempt", **cred)
+
+    Recognised schemes:
+      * Basic — base64(user:pw); decoded → ``principal=user`` +
+        ``secret_kind="plaintext"`` + ``encode_secret(pw)``.
+      * Bearer / Token — opaque token; ``principal=None`` +
+        ``secret_kind="http_bearer"`` + ``encode_secret(token)``.
+      * Digest — ``principal=username`` from header +
+        ``secret_kind="http_digest_md5"`` + ``encode_secret(response)``.
+
+    Returns ``None`` for anything unrecognized (AWS4-HMAC-SHA256, NTLM,
+    Negotiate, …) — callers can still log the raw header value in the
+    ambient SD-block; we just don't know how to extract a hashable
+    secret from it.
+    """
+    if not header_value or not isinstance(header_value, str):
+        return None
+    parts = header_value.strip().split(None, 1)
+    if len(parts) < 2:
+        return None
+    scheme, rest = parts[0].lower(), parts[1].strip()
+
+    if scheme == "basic":
+        try:
+            decoded = base64.b64decode(rest, validate=True).decode("utf-8", errors="replace")
+        except (ValueError, base64.binascii.Error):
+            return None
+        if ":" not in decoded:
+            return None
+        user, _, pw = decoded.partition(":")
+        return {
+            "principal": user,
+            "secret_kind": "plaintext",
+            **encode_secret(pw),
+        }
+
+    if scheme in ("bearer", "token"):
+        return {
+            "principal": None,
+            "secret_kind": "http_bearer",
+            **encode_secret(rest),
+        }
+
+    if scheme == "digest":
+        params: dict[str, str] = {}
+        for m in _DIGEST_PARAM_RE.finditer(rest):
+            k = m.group(1) or m.group(3)
+            v = m.group(2) if m.group(2) is not None else m.group(4)
+            if k:
+                params[k.lower()] = v
+        response = params.get("response")
+        if not response:
+            return None
+        return {
+            "principal": params.get("username"),
+            "secret_kind": "http_digest_md5",
+            **encode_secret(response),
+        }
+
+    return None
+
+
+_FORM_PRINCIPAL_KEYS = (
+    "username", "user", "email", "login", "userid", "account",
+    "log",        # wp-login.php
+    "user_login", # WordPress alt
+    "uname",      # phpMyAdmin
+    "pma_username",
+)
+_FORM_SECRET_KEYS = (
+    "password", "pass", "pwd", "passwd", "passwort", "mot_de_passe",
+    "user_password",   # WordPress alt
+    "pma_password",    # phpMyAdmin
+)
+
+
+def extract_form_credentials(
+    body: Optional[str],
+    content_type: Optional[str],
+) -> Optional[dict[str, Any]]:
+    """Parse an `application/x-www-form-urlencoded` body for credentials.
+
+    Returns the universal cred SD shape ready to spread into a
+    ``_log(...)`` call when both a principal-shaped key and a secret-
+    shaped key are present in the body. Otherwise returns ``None``.
+
+    Field-name detection is case-insensitive and covers the most common
+    login-form variants (WordPress wp-login.php, phpMyAdmin, Joomla,
+    etc.). Add more entries to ``_FORM_PRINCIPAL_KEYS`` /
+    ``_FORM_SECRET_KEYS`` as new templates surface them.
+    """
+    if not body or not isinstance(content_type, str):
+        return None
+    if not content_type.lower().startswith("application/x-www-form-urlencoded"):
+        return None
+
+    fields: dict[str, str] = {}
+    for pair in body.split("&"):
+        if "=" not in pair:
+            continue
+        k, _, v = pair.partition("=")
+        # urllib decode without importing urllib at module scope (the
+        # template emitters are import-cost-sensitive). Inline the
+        # tiny percent-decode + plus-decode.
+        try:
+            from urllib.parse import unquote_plus
+            key = unquote_plus(k).lower()
+            val = unquote_plus(v)
+        except Exception:
+            continue
+        # First-wins so duplicate-key forms don't get clobbered.
+        fields.setdefault(key, val)
+
+    principal: Optional[str] = None
+    for k in _FORM_PRINCIPAL_KEYS:
+        if k in fields:
+            principal = fields[k]
+            break
+    secret: Optional[str] = None
+    for k in _FORM_SECRET_KEYS:
+        if k in fields:
+            secret = fields[k]
+            break
+    if secret is None:
+        return None
+    return {
+        "principal": principal,
+        "secret_kind": "plaintext",
+        **encode_secret(secret),
+    }
+
+
+def write_syslog_file(line: str) -> None:
+    """Emit a syslog line to stdout for container log capture."""
+    print(line, flush=True)
+
+
+def forward_syslog(line: str, log_target: str) -> None:
+    """No-op stub. TCP forwarding is handled by rsyslog, not by service containers."""
+    pass