fix(pdf): .pdf writes, Chrome on Windows, render cleanup, unsafe options ignored

[mihailt]

Stack #818 · 07/20 · base: fix/windows-rename-retry · next: fix/structured-content

PDF rendering could reach outside the allowed folders: front matter or options could write the PDF anywhere or start any program, and the render server listened on every network interface and served the working folder, with listings, to anyone. PDF output was also broken: markdown written to a .pdf path produced nothing, and on Windows Chrome could refuse to start and a failed launch crashed the server. Rendering now has one path that releases everything it starts, the dangerous options are ignored or refused with the allowed-folder error, and several PDF, SVG, image and folder answers are corrected.

What this fixes

Problem	Fix
write_file of markdown to a .pdf path wrote nothing.	The handler builds the PDF and writes it.
🪟 Chrome refused to start when %USERPROFILE%\AppData\Local was missing.	Chrome gets the account's real profile folder.
🪟 A failed Chrome launch crashed the server about 16 s after the tool had returned its error.	Each render uses its own Chrome profile, and everything is released in finally.
🪟 With Program Files not on C: (Windows on another drive, or the folders moved), a Chrome or Chromium installed in Program Files was never found, so rendering downloaded Chrome for Testing or failed offline.	Chrome is looked for where Windows' own settings say (ProgramFiles, ProgramW6432, ProgramFiles(x86), LOCALAPPDATA), not under fixed C:\ paths.
🔒 The render server listened on all interfaces, served the working folder with listings, and stayed up after a failed render.	Its own server on 127.0.0.1, with a per-render cookie, no listings, closed on every path.
🔒 Front matter or options could write the PDF outside the allowed folders (dest, pdf_options.path), start any program (launch_options), or hang the call (devtools: true).	resolveRender() merges options and front matter once and drops these options.
🔒 write_pdf ran code from the markdown's header in the server process when gray_matter_options was given (even {} or null): it replaced md-to-pdf's defaults, which switch gray-matter's JavaScript engine off, so a ---js / ---javascript header, or any header with language: 'javascript', was evaluated.	The caller's gray-matter settings apply over md-to-pdf's defaults, and the JavaScript engine is always switched off again (js and javascript).
🔒 edit_block on a PDF wrote outputPath and read inserted PDFs (sourcePdfPath) outside the allowed folders.	validatePdfOperationPaths checks both.
🔒 write_pdf embedded files from outside the allowed folders through options.basedir or the working folder.	basedir is validated, and the render server serves only files inside the allowed folders (403 otherwise).
🔒 write_pdf read stylesheets, scripts and highlight_style from outside the allowed folders into the page.	validateRenderFiles checks them.
🔒 The other launch_options still reached Chrome: env replaced its environment (it could preload a library into Chrome, and on Windows undo the profile fix above), dumpio piped its output into the MCP connection, downloadBehavior saved downloads anywhere, debuggingPort opened DevTools on a chosen port.	Only launch options that change the render or the waits apply (headless, timeout, protocolTimeout, slowMo, defaultViewport, acceptInsecureCerts, networkEnabled, waitForInitialPage); the rest are ignored and named internally.
🔒 The allowed-folder checks above (stylesheets, scripts, highlight_style, files the page loads) checked a path, then the render looked it up again, so a link changed right after its check was read at its new target.	The render reads the path each check resolved.
⚠️ write_file append on a PDF answered "Successfully appended" and wrote nothing.	Refused, in the DOCX handler's wording.
⚠️ write_file append on an image replaced the image.	Refused ("Image append not supported.").
read_file on a PDF returned every page for an offset past the end or length 0, and cut a negative offset to its length.	No pages past the end; a negative offset reads the last N pages.
Markdown inserted into a PDF ignored insert.pdfOptions and write_pdf's options.	The inserted page follows them.
Deleting a page that doesn't exist answered "Successfully wrote PDF".	"Invalid page index", and nothing is written.
⚠️ An .svg was read as an image and written as 6 garbage bytes.	An .svg is text for read, write, edit and get_file_info; the preview widget still draws it.
An SVG read from a URL was answered as an image.	The same rule as a local .svg (isImageAnswer).
get_file_info called a folder a text (or image) file.	"fileType: directory".

Where to look

• src/tools/pdf/markdown.ts parseMarkdownToPdf(), resolveRender() (ALLOWED_LAUNCH_OPTIONS), validateRenderFiles(): the one render path, the dropped options and the file checks, whose resolved paths are what the render reads. The risky part is serveAllowedFile: the render server must serve only files inside the allowed folders, with links resolved. findSystemChrome() / windowsChromePaths(): an installed Chrome is looked for in the folders Windows names. safeGrayMatterOptions(): the header is read with the caller's gray-matter settings, never with its JavaScript engine.
• src/tools/filesystem.ts writePdf(), validatePdfOperationPaths(), getFileInfo() (folders), readFileFromUrl() (SVG URLs).
• src/utils/files/pdf.ts write() (refuses append), read() (page selection); src/tools/pdf/ pdf2md, generatePageNumbers, editPdf, insertRenderOptions, deletePages.
• src/utils/files/image.ts isImageAnswer(), src/utils/files/factory.ts getFileHandler(path, { svgAsImage }): one rule for files and URLs.
• src/utils/internal-facts.ts (new) withoutInternalFacts(), src/server.ts: write_pdf's list of ignored options stays internal and is dropped before the result is sent.

How to verify

git checkout c26a558 && npx shx rm -rf dist && node test/run-all-tests.js test-pdf-render-options.js   # fails before
git checkout fix/pdf-rendering && npx shx rm -rf dist && node test/run-all-tests.js test-pdf-render-options.js && node test/repro/run-repro.js test-pdf-launch-failure-server.js   # passes after
node test/run-all-tests.js test-client-results.js   # the client gets the old answer, no structuredContent
node test/run-all-tests.js test-pdf-render-options.js test-pdf-render-option-paths.js test-pdf-no-chrome.js test-pdf-system-chrome.js   # launch options, links changed after their check, no Chrome, Chrome not on C: (Windows)
git checkout 0b46c62 -- src/tools/pdf/markdown.ts && npx shx rm -rf dist && node test/run-all-tests.js test-pdf-front-matter-js.js   # fails before: 4 headers run their code
git checkout HEAD -- src/tools/pdf/markdown.ts && npx shx rm -rf dist && node test/run-all-tests.js test-pdf-front-matter-js.js   # passes after
node test/run-all-tests.js test-pdf-write-file-append.js test-pdf-edit-block-paths.js test-pdf-render-allowed-folders.js test-pdf-read-pages.js test-pdf-insert-options.js test-pdf-delete-missing-page.js test-pdf-render-option-paths.js test-svg-text.js test-file-info-folder.js test-image-write-file-append.js   # passes after

Answers that change

Before	After
write_file append on a PDF: "Successfully appended to …", nothing written	"PDF append not supported. Use write_pdf to modify existing PDF files."
edit_block on a PDF, outputPath or sourcePdfPath outside the allowed folders: "Successfully updated range …"	"Path not allowed: … Must be within one of these directories: …"
write_pdf, options.basedir outside the allowed folders: the outside file embedded	"Path not allowed: …"
write_pdf, a stylesheet, script or highlight_style outside the allowed folders: success, the file read in	"Path not allowed: …"
write_pdf, a highlight_style whose file is a link to a file not ending in .css: the file read in	"highlight_style … (…) is a link to a file that is not a .css file"
read_file on a PDF, offset past the last page or length 0: every page	the header and no pages
read_file on a PDF, negative offset: N pages cut to length	the last N pages, length ignored
write_pdf deleting a page that doesn't exist: "Successfully wrote PDF"	"Invalid page index", nothing written
read_file / read_multiple_files of an .svg or an SVG URL: an image block	its text
get_file_info on an .svg: "fileType: image", "isImage: true"	"fileType: text" with the line fields
get_file_info on a folder: "fileType: text" (or "image")	"fileType: directory"
write_file append on an image: "Successfully appended", the file replaced	"Error: Image append not supported.", the file unchanged
write_pdf with gray_matter_options and a JavaScript header: the header's code ran, the PDF written	the header is skipped (as without gray_matter_options), the PDF written
write_pdf with gray_matter_options.engines.js set to something that isn't a function, with a ---js header: expected "js.parse" to be a function	the header is skipped, the PDF written

write_pdf still answers "Successfully wrote PDF to …" when options are ignored; which ones, and why, stays internal.

Commits and test results

Commit	What it does
c26a558	Tests: .pdf writes, Chrome on Windows, render cleanup, ignored options.
4497035	write_file to a .pdf path writes the PDF.
39fad34	Chrome on Windows, per-render cleanup, the render server on 127.0.0.1.
888bfd0	write_pdf answers as before; the ignored options stay internal.
7a1bdbf	PdfFileHandler.write refuses mode append.
fb9ac0e	validatePdfOperationPaths checks the output path and inserted PDFs.
8500dba	basedir is validated; the server serves only allowed files.
a61f0d6	PDF pages past the end are none; a negative offset reads to the last page.
50daa21	Inserted markdown honors insert.pdfOptions and write_pdf's options.
0f3ee8f	deletePages throws "Invalid page index" before deleting.
f963bdc	validateRenderFiles: stylesheets, scripts, highlight_style.
e482835	An .svg is text for read, write, edit and get_file_info.
6dc6dd4	getFileInfo answers "fileType: directory" for a folder.
94b0276	ImageFileHandler.write refuses mode append.
8e70226	An SVG from a URL is text, as a local .svg.
c797f44	Of launch_options, only those that change the render apply.
9fcfa6f	The render reads the paths its allowed-folder checks resolved; a highlight_style link to a file not ending in .css is refused.
42338a1	The rendering tests skip, not fail, without Chrome.
61c88e9	The PDF test workspace comes from createTempDir().
d733d60	A render error names the files as the caller gave them, not where their links lead.
0b46c62	An installed Chrome is found wherever Windows keeps programs, not only on C:.
31a8020	A markdown header's code never runs, whatever gray_matter_options says.

• Full suites at the top of the stack, on main (c774c3b): Windows 11 / Node 24.18: unit 165/165, integration 4/4, repros 19/19. macOS 26.6.2 / Node 24.15: unit 165/165, integration 4/4, repros 19/19. Checks skipped for the platform, missing rights or a missing tool: 7 on Windows, 10 on macOS.
• c26a558 fails and 39fad34 passes on Windows 11 / Node 24.18.
• 888bfd0 fails before and passes after on Windows; it passes on macOS.
• 7a1bdbf to 8e70226: each fix's test fails before and passes after, on Windows 11 and macOS 26.6.2.
• c797f44, 9fcfa6f, 42338a1, d733d60: each test fails before and passes after on Windows 11 / Node 24.18 and on macOS 26.6.2 / Node 24.15. On macOS, at d733d60, the 14 test-pdf-*.js files and test-file-handlers.js pass (15/15). With 61c88e9 and d733d60, the 16 PDF-related test files pass on Windows.
• 0b46c62: test-pdf-system-chrome.js (Windows only) fails with the code before it and with main 7bad545's: each of the 6 cases found C:\Program Files\Google\Chrome\Application\chrome.exe instead of the Chrome where the setting pointed. At 0b46c62 all 6 pass, and with the machine's own settings the same Chrome as before is found. fix(pdf): .pdf writes, Chrome on Windows, render cleanup, unsafe options ignored #763's 18 test files (0 skipped) and test-pdf-launch-failure-server.js pass on Windows 11 / Node 24.18.
• 31a8020: test-pdf-front-matter-js.js fails with the code before it: a ---js header with gray_matter_options {} or null, a ---javascript header with the caller's own engines, and a plain header with language: 'javascript' ran their code in the server process. On main 7bad545, through its write_pdf path (md-to-pdf), the {}, engines and language cases ran too (null wasn't tried there), and the PDF was still written. At 31a8020 none runs, and the caller's delimiters still find the header. fix(pdf): .pdf writes, Chrome on Windows, render cleanup, unsafe options ignored #763's 19 test files (0 skipped) and test-pdf-launch-failure-server.js pass on Windows 11 / Node 24.18.
• Known and not changed:
  • Page scripts can read what the render server serves (allowed files only).
  • The render cookie also reaches other local ports.
  • Wording: write_file's description says not to write PDFs, though rewrite mode renders them.
  • Wording: write_pdf prints "Original file: " in create mode with outputPath.
  • Wording: write_pdf says outputPath "MUST be provided"; create mode writes to path.

Stack #818: #781 makes the tests run on Windows and macOS; #770–#768 fix what that exposed; #773–#779 fix the issues listed in each; #780 fixes the remote device's state; #794 reports targeted Broadcast receipts.

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📝 Walkthrough

Walkthrough

The changes update Markdown-to-PDF rendering and cleanup, PDF editing and page selection, and filesystem behavior for SVG reads, directory information, and append-mode writes.

Changes

PDF workflows

Layer / File(s)	Summary
Managed Markdown-to-PDF rendering src/tools/pdf/markdown.ts, src/tools/pdf/index.ts, test/helpers/pdf.js, test/test-pdf-render-*, test/test-pdf-launch-failure.js, test/test-pdf-system-chrome.js, test/repro/test-pdf-launch-failure-server.js	Rendering resolves and filters options, validates local render files, starts a cookie-protected localhost server, and uses a managed Puppeteer profile. Tests cover ignored options, allowed paths, Chrome discovery, launch failures, and resource cleanup.
PDF edits, paths, and option reporting src/tools/filesystem.ts, src/tools/pdf/manipulations.ts, src/utils/files/pdf.ts, src/utils/internal-facts.ts, src/server.ts, src/handlers/filesystem-handlers.ts, test/test-client-results.js, test/test-file-handlers.js, test/test-pdf-creation.js, test/test-pdf-delete-missing-page.js, test/test-pdf-edit-block-paths.js, test/test-pdf-insert-options.js, test/test-pdf-write-file-append.js	PDF operations validate output and inserted-source paths, merge render options for inserted Markdown, and reject invalid page-delete indices. write_pdf collects ignored render options, while server result processing removes structuredContent for that tool. Tests cover PDF creation, edits, path validation, option precedence, and result handling.
PDF page selection src/tools/pdf/lib/pdf2md.ts, src/tools/pdf/utils.ts, src/utils/files/pdf.ts, test/test-pdf-read-pages.js	PDF page selection distinguishes an empty array from a nonempty selection that resolves to no pages. Negative offsets select through the last page and ignore length; tests cover page ranges and edge cases.

Filesystem behavior

Layer / File(s)	Summary
File reads and directory classification src/utils/files/base.ts, src/utils/files/factory.ts, src/utils/files/image.ts, src/utils/files/index.ts, src/tools/filesystem.ts, src/handlers/filesystem-handlers.ts, test/test-svg-text.js, test/test-file-info-folder.js	SVG reads return text by default and are treated as images for UI-origin reads. Directory information uses the directory file type. Tests cover local and URL SVG reads, UI previews, and directory results.
Append-mode restrictions src/utils/files/image.ts, src/utils/files/pdf.ts, test/test-image-write-file-append.js, test/test-pdf-write-file-append.js	Image and PDF handlers reject append mode. Tests verify that existing files remain unchanged after append requests.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~60 minutes

Change: Bug fix

Suggested reviewers: wonderwhy-er

Sequence Diagram(s)

sequenceDiagram
  participant writePdf
  participant parseMarkdownToPdf
  participant renderServer
  participant Puppeteer
  participant convertMdToPdf
  writePdf->>parseMarkdownToPdf: Request PDF rendering
  parseMarkdownToPdf->>renderServer: Validate files and start localhost server
  parseMarkdownToPdf->>Puppeteer: Launch browser with temporary profile
  parseMarkdownToPdf->>convertMdToPdf: Convert Markdown using resolved options
  convertMdToPdf-->>parseMarkdownToPdf: Return PDF content
  parseMarkdownToPdf->>renderServer: Close server during cleanup
  parseMarkdownToPdf->>Puppeteer: Close browser and release profile
  parseMarkdownToPdf-->>writePdf: Return PDF content

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Merge Risk: 🟡 Moderate · up to 710eb

PDF rendering still has unresolved unsafe-option concerns that should be addressed before merging. The test now skips correctly when Chrome is unavailable.

Security Architecture Review

Security architecture risk: 🟡 Moderate · up to 710eb

The design narrows several PDF-rendering permissions, but it changes a security-sensitive workflow used by multiple file operations. The remaining uncertainty is chiefly about runtime cleanup and coverage, not a confirmed new vulnerability.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — A caller able to invoke PDF creation or modification can supply Markdown and render options that reach a privileged local browser. The examined changes constrain its executable, arguments, output destination, and served filesystem paths; they do not establish an increase in caller privilege.

Trust Boundaries and Controls

• observed — Render asset paths and each HTTP file request pass through allowed-path validation; requests without the render cookie are refused, and directory listings are disabled.

Resilience and Maintainability Implications

• inferred — Per-render cookies, profiles, and finally-block cleanup limit cross-render resource sharing and failed-launch persistence. Eventual profile deletion under sustained OS file-lock contention remains unverified.

Hardening Proposals

• proposed — Consider pinning front-matter parsing to the dependency's disabled-JavaScript engine configuration rather than accepting a caller replacement for gray_matter_options. This is defense in depth, not an established PR-introduced finding.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 58.82% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 102 functions across 34 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main PDF fixes, including .pdf writes, Chrome startup and cleanup, and ignored unsafe render options.

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Inline comments:
In `@src/tools/pdf/markdown.ts`:
- Around line 688-697: Update resolveRender’s launch_options filtering so env,
dumpio, pipe, and ignoreDefaultArgs are removed and reported as ignored before
launchOptions is spread into puppeteer.launch. Preserve the existing filtering
for executablePath and args, ensuring chromeEnv and Desktop Commander’s browser
launch controls remain authoritative.

In `@test/test-file-handlers.js`:
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• src/handlers/filesystem-handlers.ts
• src/server.ts
• src/tools/filesystem.ts
• src/tools/pdf/index.ts
• src/tools/pdf/lib/pdf2md.ts
• src/tools/pdf/manipulations.ts
• src/tools/pdf/markdown.ts
• src/tools/pdf/utils.ts
• src/utils/files/base.ts
• src/utils/files/factory.ts
• src/utils/files/image.ts
• src/utils/files/index.ts
• src/utils/files/pdf.ts
• src/utils/internal-facts.ts
• test/helpers/pdf.js
• test/repro/test-pdf-launch-failure-server.js
• test/test-client-results.js
• test/test-file-handlers.js
• test/test-file-info-folder.js
• test/test-image-write-file-append.js
• test/test-pdf-creation.js
• test/test-pdf-delete-missing-page.js
• test/test-pdf-edit-block-paths.js
• test/test-pdf-insert-options.js
• test/test-pdf-launch-failure.js
• test/test-pdf-read-pages.js
• test/test-pdf-render-allowed-folders.js
• test/test-pdf-render-option-paths.js
• test/test-pdf-render-options.js
• test/test-pdf-render-resources.js
• test/test-pdf-write-file-append.js
• test/test-svg-text.js

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Inline comments:
Review comments at @src/tools/pdf/markdown.ts:
- Around line 116-117: Update the grayMatterOptions construction used by
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override the JavaScript-engine restrictions in
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