🛡️ Sentinel: Fix DoS pipe deadlock in shell execution

[NSEvent]

🚨 Severity: HIGH
💡 Vulnerability: When executing shell commands via Foundation.Process, process.waitUntilExit() was called before draining the standard output/error pipes (pipe.fileHandleForReading.readDataToEndOfFile()). If the shell command outputs more data than the OS pipe buffer capacity (~64KB), the child process hangs waiting for space in the pipe, while the parent hangs waiting for the process to exit.
🎯 Impact: An attacker or a malfunctioning script could trivially cause a Denial of Service by printing a large amount of text, causing the application thread to deadlock indefinitely.
🔧 Fix: Swapped the order so that the pipe buffer is drained completely via readDataToEndOfFile() before calling waitUntilExit().
✅ Verification: Statically verified that the data read now correctly precedes the exit wait across instances within AutomationExecutor.swift.

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PR created automatically by Jules for task 17038624719230680235 started by @NSEvent

Summary by CodeRabbit

• Bug Fixes
  • Improved handling of command output so results are captured more reliably before processes finish.
  • Enhanced retrieval of child-process information for more consistent automation execution.

[google-labs-jules]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 664a0442-4790-4b3b-bf35-607141b70233

📥 Commits

Reviewing files that changed from the base of the PR and between 8821423 and 0fcebc5.

📒 Files selected for processing (1)

• TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift

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📝 Walkthrough

Walkthrough

AutomationExecutor now drains process output pipes before waiting for process termination in both command execution and child-process discovery paths.

Changes

Process output handling

Layer / File(s)	Summary
Drain process pipes before termination wait TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift	runProcess and childPIDs(of:) read all available pipe data before waiting for their processes to exit.

Estimated code review effort: 2 (Simple) | ~5 minutes

Possibly related PRs

• NSEvent/xbox-controller-mapper#85: Reorders stdout/stderr draining before waitUntilExit() in the same AutomationExecutor.swift paths.

Suggested reviewers: google-labs-jules[bot]

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the PR’s main change: fixing a pipe deadlock/DoS risk in shell execution.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch sentinel-fix-dos-pipe-deadlock-17038624719230680235

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