Under the oracle user, using sqlplus "/as sysdba" to log in the data fails

hello dear

1. Use sqlplus "/as sysdba" to log in as a super administrator to check whether the same problem exists
2. Please confirm whether the recent configuration has been changed, such as changing the read and write permissions of the /etc/passwd file from 644 to 640;
3. If the permissions are changed, after changing the read and write permissions of the passwd file back to 644, log in with sqlplus "/as sysdba" to check whether it is normal
4. Change the read and write permissions of the /etc/passwd file back to 644,
When using sqlplus "/as sysdba" to log in to the database as a super administrator, you need to read the /etc/passwd file.