anti
b26dd8f529
Adds per-mint nonce gating, structural shape validation, mint UUID consistency checks, and a per-(token, IP) rate limiter to the canary worker so attackers who extract a canary from a decky filesystem cannot poison fingerprint forensics by replaying or forging ?d= submissions. Changes: base.py fingerprint_nonce: Optional[str] added to CanaryArtifact so generators can surface the nonce to the cultivator without coupling the generator directly to DB code. obfuscator.py nonce_for(callback_token, mint_uuid): HMAC-SHA256 keyed on DECNET_CANARY_FINGERPRINT_SECRET, truncated to 16 hex chars. FingerprintSecretMissing raised at mint time if env var is unset. render_fingerprint_js() now accepts nonce= and substitutes MINT_NONCE. fingerprint_payload.js New MINT_NONCE placeholder. Appended as &k= on all beacon URLs (bare-open, single-shot, chunked). Using &k= avoids colliding with &n= (chunk total). fingerprint_html.py / fingerprint_svg.py Derive nonce via nonce_for() and pass to render_fingerprint_js(). Set artifact.fingerprint_nonce so the cultivator can persist it. cultivator.py Passes fingerprint_nonce into create_canary_token() when present on the artifact; NULL for all non-fingerprint generators. canary.py (model) fingerprint_nonce: Optional[str] = Field(default=None, max_length=16) added to CanaryToken. None for non-fingerprint tokens. worker.py _extract_fingerprint now returns (meta_dict, parsed_fp) tuple. _record_hit accepts parsed_fp + raw_nonce and runs 4 layers after token lookup: nonce match, shape check, mint UUID consistency, rate limit. Each failure sets _fp_invalid_* flag and drops structured _fp. Trigger row always lands regardless. tests/canary/conftest.py Session-scoped autouse fixture sets DECNET_CANARY_FINGERPRINT_SECRET so fingerprint generator and worker tests work offline. tests 5 new worker HTTP tests and 2 new generator tests covering each validation layer.
89 lines
3.6 KiB
Python
89 lines
3.6 KiB
Python
"""SVG fingerprint canary — standalone SVG with an embedded ``<script>``
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that runs the obfuscated fingerprinter when the file is opened directly
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in a browser.
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SVG ``<script>`` only fires when the SVG is loaded as a top-level
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document (or via ``<object>``/``<iframe>``); it's *blocked* when the
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SVG is referenced from another page's ``<img>``. That's the right
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posture for canary use: an attacker browsing the decky filesystem and
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double-clicking a stray ``network_diagram.svg`` triggers it; rendering
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inside a sandboxed CMS preview does not.
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Same determinism guarantees as :mod:`fingerprint_html`.
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"""
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from __future__ import annotations
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from decnet.canary.base import CanaryArtifact, CanaryContext, CanaryGenerator
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from decnet.canary.generators.fingerprint_html import _mint_uuid_for, _stable_int
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from decnet.canary.obfuscator import render_fingerprint_js, nonce_for
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_DIAGRAM_TEMPLATE = """<?xml version="1.0" encoding="UTF-8"?>
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<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 600 360" width="600" height="360">
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<style>
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.box{{fill:#f7f9fb;stroke:#7a93ad;stroke-width:1.2}}
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.lbl{{font:12px Segoe UI,Arial,sans-serif;fill:#2a3a4a}}
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.edge{{stroke:#7a93ad;stroke-width:1.2;fill:none}}
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.title{{font:bold 14px Segoe UI,Arial,sans-serif;fill:#1a2a3a}}
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.cap{{font:10px Segoe UI,Arial,sans-serif;fill:#6a7a8a}}
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</style>
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<text class="title" x="20" y="28">Network Topology — {region} segment</text>
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<text class="cap" x="20" y="44">draft v{ver} · last reviewed {review}</text>
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<rect class="box" x="40" y="80" width="120" height="50" rx="4"/>
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<text class="lbl" x="100" y="110" text-anchor="middle">edge gw</text>
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<rect class="box" x="240" y="80" width="120" height="50" rx="4"/>
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<text class="lbl" x="300" y="110" text-anchor="middle">core sw</text>
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<rect class="box" x="440" y="80" width="120" height="50" rx="4"/>
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<text class="lbl" x="500" y="110" text-anchor="middle">app cluster</text>
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<rect class="box" x="240" y="220" width="120" height="50" rx="4"/>
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<text class="lbl" x="300" y="250" text-anchor="middle">db tier</text>
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<path class="edge" d="M160 105 L240 105"/>
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<path class="edge" d="M360 105 L440 105"/>
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<path class="edge" d="M300 130 L300 220"/>
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<script type="application/ecmascript"><![CDATA[
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{payload}
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]]></script>
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</svg>
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"""
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_REGIONS = ("us-east", "eu-central", "ap-south", "us-west", "sa-east")
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class FingerprintSvgGenerator(CanaryGenerator):
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"""Synthesise an SVG that fingerprints the browser opening it."""
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name = "fingerprint_svg"
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def generate(self, ctx: CanaryContext) -> CanaryArtifact:
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mint_uuid = _mint_uuid_for(ctx.callback_token)
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nonce = nonce_for(ctx.callback_token, mint_uuid)
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payload = render_fingerprint_js(
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callback_token=ctx.callback_token,
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http_base=ctx.http_base,
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mint_uuid=mint_uuid,
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nonce=nonce,
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)
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region = _REGIONS[_stable_int(ctx.callback_token, "reg") % len(_REGIONS)]
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ver = 1 + (_stable_int(ctx.callback_token, "ver") % 6)
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day = _stable_int(ctx.callback_token, "day") % 28 + 1
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body = _DIAGRAM_TEMPLATE.format(
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region=region,
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ver=ver,
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review=f"2026-03-{day:02d}",
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payload=payload,
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)
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beacon = f"{ctx.http_base.rstrip('/')}/c/{ctx.callback_token}"
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return CanaryArtifact(
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path="",
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content=body.encode("utf-8"),
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mode=0o644,
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mtime_offset=-86400 * 30,
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generator=self.name,
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fingerprint_nonce=nonce,
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notes=[
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f"obfuscated fingerprinter beacons={beacon}",
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f"mint_uuid={mint_uuid}",
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],
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)
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