🛡️ Sentinel: [CRITICAL] Fix command injection in PDF compilation

[anchapin]

🚨 Severity: CRITICAL
💡 Vulnerability: Command injection/Remote Code Execution (RCE) via pdflatex and pandoc during PDF compilation in PDFConverter and CoverLetterGenerator.
🎯 Impact: Malicious user input or hallucinated LaTeX control characters could inject arbitrary shell commands.
🔧 Fix: Add -no-shell-escape flag to pdflatex and --pdf-engine-opt=-no-shell-escape to pandoc. Added timeout=30 to subprocess.communicate() calls to prevent DoS.
✅ Verification: Ran tests/test_pdf_security.py to ensure flags and timeout behavior function safely. All tests pass and linter passes.

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PR created automatically by Jules for task 10565898894670016090 started by @anchapin

Summary by Sourcery

Harden PDF compilation against command injection and long-running processes by enforcing shell-escape disabling and adding timeouts to external LaTeX/Pandoc calls.

Bug Fixes:

• Disable shell escape in pdflatex and pandoc-based PDF generation to prevent command injection and remote code execution.
• Add 30-second timeouts and process kill handling to PDF compilation subprocesses to avoid denial-of-service from hanging converters.

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[sourcery-ai]

Reviewer's Guide

Harden PDF compilation against command injection and DoS by disabling shell escape in pdflatex/pandoc and enforcing a 30s timeout on all LaTeX compilation subprocesses.

Sequence diagram for hardened PDF compilation with timeout and no shell escape

sequenceDiagram
    title Hardened PDF compilation flow with timeout and no shell escape
    actor User
    participant CLIApp
    participant PDFCompiler
    participant Subprocess
    participant PdfEngine

    User->>CLIApp: request PDF generation
    CLIApp->>PDFCompiler: compile(tex_content, output_path)

    rect rgb(230,230,255)
        PDFCompiler->>Subprocess: Popen([pdflatex|pandoc, -interaction=nonstopmode, -no-shell-escape,...])
        Subprocess->>PdfEngine: start process with args
        PdfEngine-->>Subprocess: running

        alt completes within 30s
            PDFCompiler->>Subprocess: communicate(timeout=30)
            Subprocess-->>PDFCompiler: stdout, stderr
            PDFCompiler->>PDFCompiler: check returncode or output_path.exists()
            alt success
                PDFCompiler-->>CLIApp: True (PDF created)
                CLIApp-->>User: return generated PDF
            else failure
                PDFCompiler-->>CLIApp: False (compilation failed)
                CLIApp-->>User: report compilation error
            end
        else exceeds 30s
            PDFCompiler->>Subprocess: communicate(timeout=30)
            Subprocess-->>PDFCompiler: TimeoutExpired exception
            PDFCompiler->>Subprocess: kill()
            PDFCompiler->>Subprocess: communicate()
            Subprocess-->>PDFCompiler: stdout, stderr
            PDFCompiler-->>CLIApp: raise RuntimeError
            CLIApp-->>User: report PDF compilation timed out
        end
    end

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Updated class diagram for PDF compilation helpers with security hardening

classDiagram
    class CoverLetterGenerator {
        +_compile_pdf(output_path, tex_content) bool
    }

    class PDFConverter {
        +_compile_pdflatex(tex_path, output_path, working_dir) bool
        +_compile_pandoc(tex_path, output_path, working_dir) bool
    }

    class SubprocessModule {
        +Popen(args, stdout, stderr, cwd) Process
    }

    class Process {
        +communicate(timeout) stdout_stderr
        +kill() void
        +returncode int
    }

    class PdfLatexEngine {
        +exec(-interaction=nonstopmode, -no-shell-escape, tex_name) void
    }

    class PandocEngine {
        +exec(tex_path, output_path, --pdf-engine=xelatex, --pdf-engine-opt=-no-shell-escape) void
    }

    CoverLetterGenerator ..> SubprocessModule : uses
    PDFConverter ..> SubprocessModule : uses

    SubprocessModule ..> Process : returns
    Process ..> PdfLatexEngine : runs
    Process ..> PandocEngine : runs

    CoverLetterGenerator ..> PdfLatexEngine : compiles
    CoverLetterGenerator ..> PandocEngine : fallback

    PDFConverter ..> PdfLatexEngine : _compile_pdflatex
    PDFConverter ..> PandocEngine : _compile_pandoc

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File-Level Changes

Change	Details	Files
Harden pdflatex invocation in cover letter PDF generation against RCE and DoS.	Add -no-shell-escape flag to the pdflatex command to prevent shell escapes in LaTeX documents. Wrap subprocess.communicate() with a 30-second timeout and kill the process on timeout to avoid hanging compilations, then raise a RuntimeError. Preserve existing success criteria by checking both process return code and output PDF existence.	cli/generators/cover_letter_generator.py
Harden both pdflatex and pandoc-based PDF compilation in the core PDF converter against RCE and DoS.	Add -no-shell-escape flag to the pdflatex command to disable LaTeX shell escapes. Extend pandoc invocation with --pdf-engine-opt=-no-shell-escape when using xelatex as the PDF engine. Wrap all subprocess.communicate() calls with a 30-second timeout, killing the process and raising RuntimeError on timeout, while keeping existing success checks based on return code and output file existence.	cli/pdf/converter.py

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[sourcery-ai]

Hey - I've left some high level feedback:

• The new timeout handling logic for pdflatex and pandoc is duplicated in multiple places; consider extracting a small helper (e.g., run_with_timeout(cmd, cwd, timeout=30)) to centralize process execution, timeout, and error behavior.
• On RuntimeError("PDF compilation timed out"), stdout/stderr are currently discarded; capturing and attaching stderr (or at least logging it) would make diagnosing misconfigurations or unexpected hangs much easier while keeping the call sites unchanged.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- The new timeout handling logic for `pdflatex` and `pandoc` is duplicated in multiple places; consider extracting a small helper (e.g., `run_with_timeout(cmd, cwd, timeout=30)`) to centralize process execution, timeout, and error behavior.
- On `RuntimeError("PDF compilation timed out")`, stdout/stderr are currently discarded; capturing and attaching stderr (or at least logging it) would make diagnosing misconfigurations or unexpected hangs much easier while keeping the call sites unchanged.

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