# Jails, UID's and security



## badaei (Apr 20, 2011)

Hello,

I realized recently that if I *vipw* in a jail and change user UIDs to that of other UIDs of other jails I cause memory conflicts in the other jail that run processes under said UID. Also not sure what would happen if I change the UID of a jail user (from within the jail!) to that of a user on the base system... like say root or toor. 

Is there something I can do as a precaution to prevent a jail from changing UID's of users or some other precaution?

Thanks for your suggestions.


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## SirDice (Apr 20, 2011)

I have various jails running with processes using the same UID. Never had any issues.

You do need to be careful when allowing IPC/shared memory though. As I understood it they all use the same namespace which would mean a process in a jail could access the IPC/shared memory of another.


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