The following table shows directory and file permissions for the generic binary distribution installation of MySQL Enterprise Edition for Linux x86-64 on Oracle Linux that is described in this guide.
As a general rule, distributed files and resources should follow the principal of least privilege, which requires that users, processes, programs, and other system components only have access to information and resources that are required for their legitimate purpose.
      As indicated previously, most of the MySQL installation can be
      owned by root. The exceptions are the data
      directory, the error log file, the
      mysql-files directory, the pid file, and the
      socket file, to which the mysql user must have
      write access. Files and resources that the
      mysql user requires read access to include
      configuration files (/etc/my.cnf) and the
      MySQL binaries (/usr/local/mysql/bin).
    
Table E.1 MySQL Linux Generic Binary Installation Directory and File Permissions
| File or Resource | Location | Owner | Directory Permissions | File Permissions | 
|---|---|---|---|---|
| Client and utility programs directory | /usr/local/mysql/bin | root | drwxr-xr-x | |
| mysqld server | /usr/local/mysql/bin | root | drwxr-xr-x | -rwxr-xr-x | 
| MySQL configuration file | /etc/my.cnf | root | drwxr-xr-x | -rw-r--r-- | 
| Data directory | /usr/local/mysql/data | mysql | drwxr-x--- | |
| Error log file | /usr/local/mysql/data/host_name.err | mysql | drwxr-x--- | -rw------- | 
secure_file_priv directory | 
/usr/local/mysql/mysql-files | mysql | drwxr-x--- | |
| mysqld systemd service file | /usr/lib/systemd/system/mysqld.service | root | drwxr-xr-x | -rw-r--r-- | 
| systemd tmpfiles configuration file | /usr/lib/tmpfiles.d/mysql.conf | root | drwxr-xr-x | -rw-r--r-- | 
| pid file | /usr/local/mysql/data/mysqld.pid | mysql | drwxr-x--- | -rw-r----- | 
| socket file | /tmp/mysql.sock | mysql | drwxrwxrwt | srwxrwxrwx | 
| Unix manual pages directory | /usr/local/mysql/man | root | drwxr-xr-x | |
| Include Header files directory | /usr/local/mysql/include | root | drwxr-xr-x | |
| Libraries directory | /usr/local/mysql/lib | root | drwxr-xr-x | |
| Miscellaneous support files directory | /usr/local/mysql/support-files | root | drwxr-xr-x | |
| Miscellaneous files directory | /usr/local/mysql/share | root | drwxr-xr-x |