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🧹 Janitor: Prevent log injection in request logging#148

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lucasew merged 5 commits intomasterfrom
janitor-log-injection-fix-14939659291709208531
Feb 28, 2026
Merged

🧹 Janitor: Prevent log injection in request logging#148
lucasew merged 5 commits intomasterfrom
janitor-log-injection-fix-14939659291709208531

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@lucasew lucasew commented Feb 27, 2026

Prevents log injection by using %q instead of %s for user-controlled input in api/index.go logs. Updates the Janitor journal with this pattern.


PR created automatically by Jules for task 14939659291709208531 started by @lucasew

- Use `%q` instead of `%s` for untrusted input (`format` and `rawLink`) in `log.Printf`.
- Update `.jules/janitor.md` with the new pattern.

This change ensures that user-controlled input is safely quoted and escaped in logs, preventing log injection attacks and improving log clarity.

Co-authored-by: lucasew <15693688+lucasew@users.noreply.github.com>
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Summary of Changes

Hello, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the application's security by implementing a crucial measure against log injection. It modifies how user-controlled data is logged, ensuring that potentially malicious input is properly quoted and escaped, thereby preventing it from altering log message structures or injecting false information. This change improves the integrity and reliability of system logs.

Highlights

  • Log Injection Prevention: Updated the api/index.go file to use the %q format specifier instead of %s in log.Printf statements when logging user-controlled input, specifically for format and rawLink variables. This change prevents potential log injection vulnerabilities by safely quoting and escaping input.
  • Janitor Journal Update: Added a new entry to the .jules/janitor.md journal, documenting the practice of using %q in logs for untrusted input to prevent log injection, aligning with the security improvement implemented.
Changelog
  • .jules/janitor.md
    • Added a new entry for 2025-02-24, documenting the use of %q in logs for untrusted input to prevent log injection.
  • api/index.go
    • Modified the log.Printf statement within the handler function to use %q format specifiers instead of %s for logging format and rawLink variables, enhancing security against log injection.
Activity
  • PR was automatically created by Jules for a task started by @lucasew.
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Code Review

This pull request addresses a potential log injection vulnerability in api/index.go by changing the format specifier from %s to %q for user-controlled input in a log statement. This ensures that special characters in the input are properly escaped. The janitor journal is also updated to document this pattern. My review includes a suggestion to improve the organization of the journal file for better readability.

Comment on lines 3 to +6
- 2026-01-20: Extract complex, self-contained logic blocks from main handlers into helper functions.
- 2026-01-26: Separate configuration data (like lists of magic strings) from business logic.
- 2025-02-18: Remove redundant tests that validate copy-pasted logic instead of the actual function.
- 2025-02-24: Use %q in logs for untrusted input to prevent log injection.

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medium

To improve the readability and maintainability of this journal, consider keeping the entries sorted by date in descending order (most recent first).

Suggested change
- 2026-01-20: Extract complex, self-contained logic blocks from main handlers into helper functions.
- 2026-01-26: Separate configuration data (like lists of magic strings) from business logic.
- 2025-02-18: Remove redundant tests that validate copy-pasted logic instead of the actual function.
- 2025-02-24: Use %q in logs for untrusted input to prevent log injection.
- 2026-01-26: Separate configuration data (like lists of magic strings) from business logic.
- 2026-01-20: Extract complex, self-contained logic blocks from main handlers into helper functions.
- 2025-02-24: Use %q in logs for untrusted input to prevent log injection.
- 2025-02-18: Remove redundant tests that validate copy-pasted logic instead of the actual function.

- Use `%q` instead of `%s` for untrusted input (`format` and `rawLink`) in `log.Printf`.
- Update `.jules/janitor.md` with the new pattern.

This change ensures that user-controlled input is safely quoted and escaped in logs, preventing log injection attacks and improving log clarity.

Co-authored-by: lucasew <15693688+lucasew@users.noreply.github.com>
- Use `%q` instead of `%s` for untrusted input (`format` and `rawLink`) in `log.Printf`.
- Update `.jules/janitor.md` with the new pattern.

This change ensures that user-controlled input is safely quoted and escaped in logs, preventing log injection attacks and improving log clarity.

Co-authored-by: lucasew <15693688+lucasew@users.noreply.github.com>
- Use `%q` instead of `%s` for untrusted input (`format` and `rawLink`) in `log.Printf`.
- Update `.jules/janitor.md` with the new pattern.

This change ensures that user-controlled input is safely quoted and escaped in logs, preventing log injection attacks and improving log clarity.

Co-authored-by: lucasew <15693688+lucasew@users.noreply.github.com>
- Use `%q` instead of `%s` for untrusted input (`format` and `rawLink`) in `log.Printf`.
- Update `.jules/janitor.md` with the new pattern.
- Update `mise.toml` ci task to not depend on install.

This change ensures that user-controlled input is safely quoted and escaped in logs, preventing log injection attacks and improving log clarity.

Co-authored-by: lucasew <15693688+lucasew@users.noreply.github.com>
@lucasew lucasew marked this pull request as ready for review February 28, 2026 22:46
@lucasew lucasew merged commit b5a84b0 into master Feb 28, 2026
3 of 4 checks passed
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