anti
f2b3393669
Replaces LICENSE (GPLv3 -> AGPLv3) and prepends `SPDX-License-Identifier: AGPL-3.0-or-later` to every source file across decnet/, decnet_web/, tests/, scripts/, and tools/. Rationale: closes the GPLv3 ASP loophole so any party operating a modified DECNET as a network service must offer their modified source. Personal copyright (Samuel Paschuan) + inbound=outbound contributions make a future unilateral relicense infeasible. - LICENSE: full AGPL-3.0 text (gnu.org/licenses/agpl-3.0.txt) - COPYRIGHT: project copyright notice - tools/add_spdx_headers.py: idempotent header injector (shebang- and PEP 263-aware) Touches 1565 source files (.py, .ts, .tsx, .js, .jsx, .css, .sh). No behavior change; comments only.
78 lines
2.8 KiB
Python
78 lines
2.8 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-or-later
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"""PDF instrumenter — requires :mod:`pikepdf` (optional dependency).
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PDF embedding is non-trivial: the cleanest place to put a callback
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is an ``/AA`` (additional actions) ``/O`` (open) entry on the
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catalog or a ``/URI`` action on a link annotation. Either path
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needs proper xref-table updates — pikepdf handles that for us.
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If pikepdf isn't available in the environment the instrumenter
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raises :class:`InstrumenterRejectedError` so the API can return a
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clear 400 directing the operator to either install pikepdf or
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re-upload as ``passthrough``.
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We don't ship a stdlib fallback because every "naive" PDF mutation
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I'm aware of (appending raw bytes, splicing into the trailer, etc.)
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breaks the document's xref table and trips a "file is corrupt"
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warning in modern viewers — which the attacker will absolutely
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notice.
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"""
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from __future__ import annotations
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from decnet.canary.base import (
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CanaryArtifact,
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CanaryContext,
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CanaryInstrumenter,
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InstrumenterRejectedError,
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)
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class PdfInstrumenter(CanaryInstrumenter):
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name = "pdf"
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mime_prefixes = ("application/pdf",)
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def instrument(
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self, blob: bytes, ctx: CanaryContext, *, target_path: str,
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) -> CanaryArtifact:
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try:
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import pikepdf
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except ImportError as e:
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raise InstrumenterRejectedError(
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"PDF instrumenter requires pikepdf; install it (`pip "
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"install pikepdf`) or re-upload the artifact with "
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"kind=passthrough so it ships unmodified."
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) from e
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url = f"{ctx.http_base.rstrip('/')}/c/{ctx.callback_token}"
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try:
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import io
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buf = io.BytesIO(blob)
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with pikepdf.open(buf) as pdf:
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# Add an OpenAction that fires a URI action on document
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# open. Most viewers prompt before fetching; that's
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# fine — even the prompt itself can trip a "user
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# interacted with the document" tell, and an
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# auto-allow viewer fetches the URL silently.
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action = pikepdf.Dictionary(
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Type=pikepdf.Name("/Action"),
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S=pikepdf.Name("/URI"),
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URI=pikepdf.String(url),
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)
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pdf.Root[pikepdf.Name("/OpenAction")] = action
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out = io.BytesIO()
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pdf.save(out)
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mutated = out.getvalue()
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except Exception as e:
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raise InstrumenterRejectedError(
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f"failed to instrument PDF: {e!s}"
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) from e
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return CanaryArtifact(
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path=target_path,
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content=mutated,
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mode=0o644,
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mtime_offset=-86400 * 14,
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instrumenter=self.name,
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notes=[f"installed /OpenAction /URI -> {url}"],
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)
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