Dear All, After switching on SELinux in MLS enforcing mode, I'd like to know how the slogan of "no read up, no write down" works. I created some text files with the following descriptions TestFile_S0 system_u:object_r:usr_t:s0 TestFile_S0C2 system_u:object_r:usr_t:s0:c2 TestFile_S1 system_u:object_r:usr_t:s1 TestFile_S2 system_u:object_r:usr_t:s2 TestFile_S2C11 system_u:object_r:usr_t:s2:c11 TestFile_S2C5 system_u:object_r:usr_t:s2:c5 TestFile_S3 system_u:object_r:usr_t:s3 TestFile_S3C14 system_u:object_r:usr_t:s3:c14 TestFile_S3C5 system_u:object_r:usr_t:s3:c5 After creating these text file, I went to create users having different security clearance; The clearance of each created user is listed bellow: Login Name SELinux User Role MLS/MCS Range first x_first xguest_r s0 second x_second sysadm_r s3-s3:c5.c15 third x_third sysadm_r s1:c3.c15-s3:c5.c10 forth x_forth system_r s1-s1:c0.c10 root root system_r s0-s15:c0.c1023 having the clearance delegated for each user I expect user first have read write access to TestFile_S0 and just write access to all other files; user second have read access to files such as TestFile_S0, TestFile_S0C2, TestFile_S2, TestFile_S2C5, TestFile_S2C11 and only write access to TestFile_S3, TestFile_S3C14. when I switch to MLS enforcing mode I see something else. These users have no permission to write to files they expect they have write access to. I'd like to know the where this problem originates Moreover when user first wants to take a list of the directory contents only TestFile_S0, TestFile_S1, TestFile_S2 are listed not else; user second sees TestFile_S0, TestFile_S1, TestFile2, TestFile3; users third and root sees all files; user forth sees just TestFile_S0 not more. I don't know why such lists are taken when I'd like to take a list. Any comment is wellcome Best Regards