🛡️ Sentinel: [CRITICAL] Fix Remote Code Execution in PDF Compilation

.jules/sentinel.md

@@ -7,3 +7,7 @@
 **Vulnerability:** The `CoverLetterGenerator` used a standard Jinja2 environment (intended for HTML/XML or plain text) to render LaTeX templates. This allowed malicious user input (or AI hallucinations) containing LaTeX control characters (e.g., `\input{...}`) to be injected directly into the LaTeX source, leading to potential Local File Inclusion (LFI) or other exploits.
 **Learning:** Jinja2's default `autoescape` is context-aware based on file extensions, but usually only for HTML/XML. It does NOT automatically escape LaTeX special characters. Relying on manual filters (like `| latex_escape`) in templates is error-prone and brittle, as developers might forget to apply them to every variable.
 **Prevention:** Always use a dedicated Jinja2 environment for LaTeX generation that enforces auto-escaping via a `finalize` hook (e.g., `tex_env.finalize = latex_escape`). This ensures *all* variable output is sanitized by default, providing defense-in-depth even if the template author forgets explicit filters.
+## 2025-03-09 - [CRITICAL] Remote Code Execution (RCE) via LaTeX Compilation
+**Vulnerability:** Untrusted LaTeX compilation commands (`pdflatex` and `pandoc` using `xelatex`) were executed via `subprocess.Popen` without the `-no-shell-escape` flag. This allows malicious LaTeX documents to execute arbitrary system commands via `\write18{}` or similar mechanisms during PDF generation.
+**Learning:** All PDF compilation tools, whether `pdflatex` directly or `pandoc` using a LaTeX engine, must be explicitly sandboxed to prevent command injection, even when the input source is semi-trusted or dynamically generated (e.g., from an LLM). Process execution should also enforce strict timeouts to prevent Denial of Service (DoS) from infinite compilation loops.
+**Prevention:** Always enforce `-no-shell-escape` directly in `pdflatex` or via `--pdf-engine-opt=-no-shell-escape` in `pandoc`. Always wrap `subprocess.Popen().communicate()` calls with a strict `timeout` argument and implement proper cleanup (`process.kill()`) for `TimeoutExpired` exceptions to avoid zombie processes.

cli/generators/cover_letter_generator.py

@@ -771,12 +771,16 @@ def _compile_pdf(self, output_path: Path, tex_content: str) -> bool:
         try:
             # Use Popen with explicit cleanup to avoid double-free issues
             process = subprocess.Popen(
-                ["pdflatex", "-interaction=nonstopmode", tex_path.name],
+                ["pdflatex", "-interaction=nonstopmode", "-no-shell-escape", tex_path.name],
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
                 cwd=tex_path.parent,
             )
-            stdout, stderr = process.communicate()
+            try:
+                stdout, stderr = process.communicate(timeout=30)
+            except subprocess.TimeoutExpired:
+                process.kill()
+                stdout, stderr = process.communicate()
             if process.returncode == 0 or output_path.exists():
                 pdf_created = True
         except (subprocess.CalledProcessError, FileNotFoundError):
@@ -787,11 +791,22 @@ def _compile_pdf(self, output_path: Path, tex_content: str) -> bool:
                 # Fallback to pandoc
                 try:
                     process = subprocess.Popen(
-                        ["pandoc", str(tex_path), "-o", str(output_path), "--pdf-engine=xelatex"],
+                        [
+                            "pandoc",
+                            str(tex_path),
+                            "-o",
+                            str(output_path),
+                            "--pdf-engine=xelatex",
+                            "--pdf-engine-opt=-no-shell-escape",
+                        ],
                         stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE,
                     )
-                    stdout, stderr = process.communicate()
+                    try:
+                        stdout, stderr = process.communicate(timeout=30)
+                    except subprocess.TimeoutExpired:
+                        process.kill()
+                        stdout, stderr = process.communicate()
                     if process.returncode == 0 or output_path.exists():
                         pdf_created = True
                 except (subprocess.CalledProcessError, FileNotFoundError):

cli/pdf/converter.py

@@ -86,12 +86,16 @@ def _compile_pdflatex(
         """
         try:
             process = subprocess.Popen(
-                ["pdflatex", "-interaction=nonstopmode", tex_path.name],
+                ["pdflatex", "-interaction=nonstopmode", "-no-shell-escape", tex_path.name],
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
                 cwd=working_dir,
             )
-            stdout, stderr = process.communicate()
+            try:
+                stdout, stderr = process.communicate(timeout=30)
+            except subprocess.TimeoutExpired:
+                process.kill()
+                stdout, stderr = process.communicate()
 
             if process.returncode == 0 or output_path.exists():
                 return True
@@ -121,12 +125,23 @@ def _compile_pandoc(
         """
         try:
             process = subprocess.Popen(
-                ["pandoc", str(tex_path), "-o", str(output_path), "--pdf-engine=xelatex"],
+                [
+                    "pandoc",
+                    str(tex_path),
+                    "-o",
+                    str(output_path),
+                    "--pdf-engine=xelatex",
+                    "--pdf-engine-opt=-no-shell-escape",
+                ],
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
                 cwd=working_dir,
             )
-            stdout, stderr = process.communicate()
+            try:
+                stdout, stderr = process.communicate(timeout=30)
+            except subprocess.TimeoutExpired:
+                process.kill()
+                stdout, stderr = process.communicate()
 
             if process.returncode == 0 or output_path.exists():
                 return True
@@ -148,7 +163,11 @@ def is_pdflatex_available(self) -> bool:
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
             )
-            process.communicate()
+            try:
+                process.communicate(timeout=10)
+            except subprocess.TimeoutExpired:
+                process.kill()
+                process.communicate()
             return process.returncode == 0
         except FileNotFoundError:
             return False
@@ -166,7 +185,11 @@ def is_pandoc_available(self) -> bool:
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE,
             )
-            process.communicate()
+            try:
+                process.communicate(timeout=10)
+            except subprocess.TimeoutExpired:
+                process.kill()
+                process.communicate()
             return process.returncode == 0
         except FileNotFoundError:
             return False