Ubuntu 16.04.3 LTS共享文件夹所有者变为Debian-exim的原因咨询

Hey there, let's break down why your Ubuntu 16.04.3 LTS server's shared folder suddenly changed ownership to Debian-exim—this user is tied to the Exim mail server, so the issue is almost certainly linked to Exim's operations. Here are the most likely causes and how to investigate them:

Possible Root Causes #

• Misconfigured Exim paths: If your shared folder was accidentally added to Exim's configuration (as a spool directory, log storage, or temp folder), Exim's routine maintenance tasks (like cleaning old logs or processing mail queues) would modify its ownership. Since Exim runs under the Debian-exim user, any write/management operations it performs on the folder will reset ownership to that user.
• Unintended cron jobs: Check if there's a scheduled task running as Debian-exim that targets your shared folder. This could be a misconfigured cleanup script or a custom task set up by mistake.
• Exim package updates: Even if you didn't manually modify the system, Ubuntu's automatic updates might have pushed an Exim package update. Rarely, post-update configuration scripts can glitch and affect unrelated directories if there's a path overlap or misconfiguration.
• Accidental mail-related writes: If an application or script running as Debian-exim wrote files to your shared folder (e.g., saving email attachments there), this would change the folder's ownership to match the user that performed the write.

Steps to Diagnose the Issue #

1. Check Exim configuration files:
   • Search for references to your shared folder path in Exim's config directory:

     grep -r "/path/to/your/shared/folder" /etc/exim4/
     

   • Focus on files like exim4.conf.template and update-exim4.conf.conf—these are the core config files for Exim on Ubuntu.
2. Review Exim logs:
   • Look for activity related to your folder in Exim's main and panic logs:

     grep "/path/to/your/shared/folder" /var/log/exim4/mainlog /var/log/exim4/paniclog
     

   • This will show if Exim performed any operations on the folder around the time the ownership changed.
3. Inspect cron tasks:
   • List cron jobs running specifically as Debian-exim:

     crontab -u Debian-exim -l
     

   • Also check system-level cron directories (/etc/cron.d/, /etc/cron.daily/, /etc/cron.hourly/) for scripts that might target your folder.
4. Verify update history:
   • Check if an Exim update coincided with the ownership change:

     cat /var/log/apt/history.log | grep -i exim
     

Once you identify the root cause (e.g., a misconfigured path or rogue cron job), you can fix it to prevent the issue from recurring. For example, if Exim was mistakenly using your shared folder, update the configuration to point to a proper mail-related directory instead.

内容的提问来源于stack exchange，提问作者user792743