Parental control
 

Heloo. I have this urgent problem with Parental control on linux. I have been set up the time in what user could be logged in- from 5pm to 10pm. It was all fine until my kid tried to prove being smarter than me :D and changed system time so he can log in about 2 hours before 5pm. Next thing i hear is "dad there is something wrong with the computer, but it's not my fault!" :D exactly after 5 hours. So, the question is, how can it be possible that time changed back to correct one and linux is now logging out all the time after 8pm, although parental control is showing that access to session will be denied after 2hours (at 10pm, as it is set in parental control settings)??
I will appreciate any help on how to fix this, thanks.

look into setting up NTP and using a trusted source. Additionally, I'm surprised that you gave your child's parental controlled account access to any administrative functions (and changing the time is administrative). Look into what permissions settings to which you have access.

Might have to restrict it with the router or modem instead. Also should have bios passworded to prevent that time change and a simple user should not have been able to change time.

Buy a paddle too.