🛡️ Sentinel: [CRITICAL] Fix RCE vulnerability in PDF compilation

[anchapin]

🚨 Severity: CRITICAL
💡 Vulnerability: PDF compilation commands for pdflatex and pandoc lacked the -no-shell-escape flags in cli/pdf/converter.py and cli/generators/cover_letter_generator.py.
🎯 Impact: Allows arbitrary shell command execution (RCE) via \write18 if a malicious payload is injected into the LaTeX source.
🔧 Fix: Added -no-shell-escape to pdflatex commands and --pdf-engine-opt=-no-shell-escape to pandoc commands during compilation.
✅ Verification: Ensure the test suite passes (python -m pytest) and PDF generation works normally.

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PR created automatically by Jules for task 11300656647367414925 started by @anchapin

Summary by Sourcery

Harden PDF compilation against remote code execution by restricting LaTeX shell access in all pdflatex and pandoc workflows.

Bug Fixes:

• Prevent potential RCE in cover letter PDF generation by adding -no-shell-escape to pdflatex and restricting pandoc’s PDF engine options.
• Prevent potential RCE in generic PDF conversion by enforcing -no-shell-escape for both pdflatex and pandoc-based compilation paths.

Documentation:

• Document the new critical RCE class in the Sentinel security log, including lessons learned and prevention guidance.

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Reviewer's Guide

Adds restrictive execution flags to all LaTeX/PDF compilation paths (pdflatex and pandoc) and documents the RCE fix in the Sentinel security log for defense-in-depth against shell escape exploits.

Sequence diagram for secured PDF compilation with no_shell_escape

sequenceDiagram
    actor User
    participant CoverLetterGenerator
    participant PdfConverter
    participant pdflatex
    participant pandoc

    User->>CoverLetterGenerator: generate_cover_letter
    CoverLetterGenerator->>PdfConverter: _compile_pdf(tex_content, output_path)

    PdfConverter->>pdflatex: subprocess.Popen(pdflatex -interaction=nonstopmode -no-shell-escape)
    alt [pdflatex succeeds]
        pdflatex-->>PdfConverter: PDF created
        PdfConverter-->>CoverLetterGenerator: return True
    else [pdflatex fails]
        PdfConverter->>pandoc: subprocess.Popen(pandoc --pdf-engine=xelatex --pdf-engine-opt=-no-shell-escape)
        pandoc-->>PdfConverter: PDF created
        PdfConverter-->>CoverLetterGenerator: return True
    end

    CoverLetterGenerator-->>User: compiled PDF

Loading

File-Level Changes

Change	Details	Files
Harden pdflatex-based PDF compilation to disable LaTeX shell escapes.	Extend pdflatex invocation in cover_letter_generator to include -no-shell-escape while preserving existing options and working directory behavior. Extend pdflatex invocation in cli/pdf/converter to include -no-shell-escape, keeping stdout/stderr capture and working-dir semantics intact. Add inline comments explaining the security rationale (RCE prevention via \write18) next to the modified subprocess.Popen calls.	cli/generators/cover_letter_generator.py cli/pdf/converter.py
Harden pandoc-based PDF compilation by passing restrictive pdf engine options.	Modify pandoc command in cover_letter_generator to pass --pdf-engine-opt=-no-shell-escape alongside the existing --pdf-engine=xelatex flag. Modify pandoc command in cli/pdf/converter to pass --pdf-engine-opt=-no-shell-escape, preserving output paths and engine selection. Add inline comments clarifying that the new flag prevents RCE via LaTeX shell escapes in the pandoc fallback path.	cli/generators/cover_letter_generator.py cli/pdf/converter.py
Document the new critical RCE vulnerability and mitigation in the Sentinel security log.	Append a dated section describing the missing -no-shell-escape flags as a critical RCE vulnerability. Capture key learnings about compiler-level hardening and defense-in-depth versus template sanitization. Record prevention guidance to always use -no-shell-escape when compiling untrusted or generated LaTeX sources.	.jules/sentinel.md

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