🛡️ Sentinel: [CRITICAL] Fix LaTeX shell escape RCE

[anchapin]

🚨 Severity: CRITICAL
💡 Vulnerability: Missing flags allowed arbitrary shell command execution if malicious LaTeX was injected.
🎯 Impact: Prevents RCE and protects the system from arbitrary command execution.
🔧 Fix: Disabled shell escapes in pdflatex and pandoc during PDF compilation.
✅ Verification: Verified via unit tests that compilation proceeds successfully while blocking shell escapes.

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PR created automatically by Jules for task 15206891120435747647 started by @anchapin

Summary by Sourcery

Harden LaTeX-based PDF generation against remote code execution by disabling shell escapes in all compilation paths and documenting the vulnerability and its mitigation in Sentinel notes.

Bug Fixes:

• Disable LaTeX shell escapes in pdflatex and pandoc-based PDF compilation to prevent arbitrary command execution when handling untrusted LaTeX content.

Documentation:

• Add Sentinel security note describing the LaTeX shell escape RCE vulnerability, its risks, and required compilation flags to prevent it.

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[sourcery-ai]

Reviewer's Guide

This PR hardens PDF generation by explicitly disabling LaTeX shell escapes for both pdflatex and pandoc-based compilation paths, and documents the vulnerability and its mitigation in the Sentinel security log.

Sequence diagram for hardened LaTeX PDF compilation

sequenceDiagram
    participant CoverLetterGenerator
    participant subprocess
    participant pdflatex
    participant pandoc

    CoverLetterGenerator->>subprocess: Popen(["pdflatex", "-interaction=nonstopmode", "-no-shell-escape", tex_path.name])
    subprocess->>pdflatex: execute pdflatex
    pdflatex-->>CoverLetterGenerator: returncode

    alt pdflatex_success
        CoverLetterGenerator-->>CoverLetterGenerator: use pdflatex PDF output
    else pdflatex_failure
        CoverLetterGenerator->>subprocess: Popen(["pandoc", tex_path, "-o", output_path, "--pdf-engine=xelatex", "--pdf-engine-opt=-no-shell-escape"]) 
        subprocess->>pandoc: execute pandoc
        pandoc-->>CoverLetterGenerator: returncode
    end

Loading

File-Level Changes

Change	Details	Files
Disable LaTeX shell escapes during pdflatex and pandoc compilation in the cover letter generator.	Add -no-shell-escape flag to pdflatex invocation when compiling cover letters. Add --pdf-engine-opt=-no-shell-escape to pandoc invocation using xelatex as the pdf engine. Update inline comments to highlight RCE prevention via disabled shell-escape flags.	cli/generators/cover_letter_generator.py
Disable LaTeX shell escapes during pdflatex and pandoc compilation in the generic PDF converter.	Add -no-shell-escape flag to pdflatex invocation in the converter. Add --pdf-engine-opt=-no-shell-escape to pandoc invocation in the converter. Update inline comments to clarify intent to block LaTeX-based RCE via shell escapes.	cli/pdf/converter.py
Document the LaTeX shell escape RCE vulnerability and its mitigation in the Sentinel security record.	Add a new Sentinel entry describing the missing -no-shell-escape flag vulnerability in LaTeX compilation. Explain why LaTeX compilation on untrusted input is unsafe without shell escape restrictions. Record preventive guidance to always pass -no-shell-escape for pdflatex and corresponding options for pandoc, with caveat for non-compilation utility commands.	.jules/sentinel.md

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[sourcery-ai]

Hey - I've left some high level feedback:

• The pdflatex and pandoc invocation arguments are now duplicated in multiple places; consider centralizing command construction (e.g., a helper that injects the -no-shell-escape / --pdf-engine-opt flags) to keep the shell-escape policy consistent and easier to maintain.
• If there are any other LaTeX compilation paths in the codebase (e.g., different generators or utilities), it would be worth checking that they also explicitly pass -no-shell-escape / --pdf-engine-opt=-no-shell-escape to avoid inconsistent hardening.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- The pdflatex and pandoc invocation arguments are now duplicated in multiple places; consider centralizing command construction (e.g., a helper that injects the `-no-shell-escape` / `--pdf-engine-opt` flags) to keep the shell-escape policy consistent and easier to maintain.
- If there are any other LaTeX compilation paths in the codebase (e.g., different generators or utilities), it would be worth checking that they also explicitly pass `-no-shell-escape` / `--pdf-engine-opt=-no-shell-escape` to avoid inconsistent hardening.

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