🛡️ Sentinel: [CRITICAL] Fix symlink attack vulnerability in burnrate#91
🛡️ Sentinel: [CRITICAL] Fix symlink attack vulnerability in burnrate#91
Conversation
Co-authored-by: himattm <6266621+himattm@users.noreply.github.com>
|
👋 Jules, reporting for duty! I'm here to lend a hand with this pull request. When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down. I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job! For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with New to Jules? Learn more at jules.google/docs. For security, I will only act on instructions from the user who triggered this task. |
![gemini-code-assist[bot]](https://avatars.githubusercontent.com/in/956858?s=60&v=4){kind=small}
There was a problem hiding this comment.
Code Review
This pull request addresses a security vulnerability by replacing predictable temporary file creation with os.CreateTemp in internal/burnrate/burnrate.go and adding documentation to the sentinel log. Feedback suggests improving the implementation's robustness by using defer for file closure to prevent resource leaks and incorporating tmpFile.Sync() to ensure data durability before the file is renamed.
| tmpFile, err := os.CreateTemp(filepath.Dir(path), "prism-burn-tmp-*") | ||
| if err != nil { | ||
| return nil, false, err | ||
| } | ||
| tmpPath := tmpFile.Name() | ||
|
|
||
| // Ensure cleanup if we fail before rename | ||
| defer os.Remove(tmpPath) | ||
|
|
||
| if _, err := tmpFile.Write(data); err != nil { | ||
| tmpFile.Close() | ||
| return nil, false, err | ||
| } | ||
|
|
||
| if err := tmpFile.Chmod(0644); err != nil { | ||
| tmpFile.Close() | ||
| return nil, false, err | ||
| } | ||
|
|
||
| if err := tmpFile.Close(); err != nil { | ||
| return nil, false, err | ||
| } |
There was a problem hiding this comment.
While the use of os.CreateTemp correctly addresses the symlink vulnerability, the implementation can be made more robust and durable by following standard Go idioms for file operations:
- Resource Management: Using
defer tmpFile.Close()ensures the file descriptor is always closed, preventing leaks in case of panics or future code changes that add early returns. - Data Durability: Adding
tmpFile.Sync()before closing ensures that data is flushed to stable storage. This prevents data loss or corruption if the system crashes after the rename but before the OS flushes its buffers. - Simplification: Using
deferallows removing redundant manualClose()calls in error paths, making the code cleaner and less error-prone.
tmpFile, err := os.CreateTemp(filepath.Dir(path), "prism-burn-tmp-*")
if err != nil {
return nil, false, err
}
tmpPath := tmpFile.Name()
defer os.Remove(tmpPath)
defer tmpFile.Close()
if _, err := tmpFile.Write(data); err != nil {
return nil, false, err
}
if err := tmpFile.Sync(); err != nil {
return nil, false, err
}
if err := tmpFile.Chmod(0644); err != nil {
return nil, false, err
}
if err := tmpFile.Close(); err != nil {
return nil, false, err
}
Understood. Acknowledging that this work is now obsolete and stopping work on this task. |
1 participant
🚨 Severity: CRITICAL
💡 Vulnerability: Predictable temporary filenames used before renaming in shared directories (like
/tmp) expose the application to local symlink attacks. An attacker can pre-create the predictable.tmpfile as a symlink, allowing local file overwrite.🎯 Impact: An attacker could potentially overwrite critical system or user files with the burnrate json data.
🔧 Fix: Utilized
os.CreateTempto securely generate an unpredictable temporary file in the target directory (filepath.Dir(path)) instead of usingpath + ".tmp". Also ensured the permissions are explicitly set to match original behavior (0644).✅ Verification: The modification was verified through code review and by successfully passing the test suite (
go test ./...) which showed no regressions.PR created automatically by Jules for task 5105896159643456558 started by @himattm