refactor: strip DECNET tokens from container-visible surface

Rename the container-side logging module decnet_logging → syslog_bridge
(canonical at templates/syslog_bridge.py, synced into each template by
the deployer). Drop the stale per-template copies; setuptools find was
picking them up anyway. Swap useradd/USER/chown "decnet" for "logrelay"
so no obvious token appears in the rendered container image.

Apply the same cloaking pattern to the telnet template that SSH got:
syslog pipe moves to /run/systemd/journal/syslog-relay and the relay
is cat'd via exec -a "systemd-journal-fwd". rsyslog.d conf rename
99-decnet.conf → 50-journal-forward.conf. SSH capture script:
/var/decnet/captured → /var/lib/systemd/coredump (real systemd path),
logger tag decnet-capture → systemd-journal. Compose volume updated
to match the new in-container quarantine path.

SD element ID shifts decnet@55555 → relay@55555; synced across
collector, parser, sniffer, prober, formatter, tests, and docs so the
host-side pipeline still matches what containers emit.
This commit is contained in:
2026-04-17 22:57:53 -04:00
parent 69510fb880
commit 8dd4c78b33
114 changed files with 220 additions and 2712 deletions

View File

@@ -8,13 +8,13 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
ENV PIP_BREAK_SYSTEM_PACKAGES=1
RUN pip3 install --no-cache-dir impacket jinja2
COPY decnet_logging.py /opt/decnet_logging.py
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 445 139
RUN useradd -r -s /bin/false -d /opt decnet \
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)
@@ -22,5 +22,5 @@ RUN useradd -r -s /bin/false -d /opt decnet \
HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
CMD kill -0 1 || exit 1
USER decnet
USER logrelay
ENTRYPOINT ["/entrypoint.sh"]

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@@ -1,89 +0,0 @@
#!/usr/bin/env python3
"""
Shared RFC 5424 syslog helper for DECNET service templates.
Services call syslog_line() to format an RFC 5424 message, then
write_syslog_file() to emit it to stdout — Docker 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), PEN for SD element ID: decnet@55555
"""
from datetime import datetime, timezone
from typing import Any
# ─── Constants ────────────────────────────────────────────────────────────────
_FACILITY_LOCAL0 = 16
_SD_ID = "decnet@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 (decky 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 write_syslog_file(line: str) -> None:
"""Emit a syslog line to stdout for Docker log capture."""
print(line, flush=True)
def forward_syslog(line: str, log_target: str) -> None:
"""No-op stub. TCP forwarding is now handled by rsyslog, not by service containers."""
pass

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@@ -7,7 +7,7 @@ Logs all connection attempts, optionally forwarding them as JSON to LOG_TARGET.
import os
from impacket import smbserver
from decnet_logging import syslog_line, write_syslog_file, forward_syslog
from syslog_bridge import syslog_line, write_syslog_file, forward_syslog
NODE_NAME = os.environ.get("NODE_NAME", "WORKSTATION")
SERVICE_NAME = "smb"