Messages in this thread | | | From | Kenton Varda <> | Date | Thu, 28 May 2015 13:17:30 -0700 | Subject | Re: [PATCH] devpts: Add ptmx_uid and ptmx_gid options |
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On Thu, May 28, 2015 at 1:06 PM, Alexander Larsson <alexl@redhat.com> wrote: > On Thu, 2015-05-28 at 12:14 -0500, Eric W. Biederman wrote: >> >> > Where does the second namespace enter into this? >> >> Step a. Create create a user namespace where uid 0 is mapped to your >> real uid, and set up your sandbox (aka mount /dev/pts and everything >> else). >> >> Step b. Create a nested user namespace where your uid is identity >> mapped and run your desktop application. You can even drop all caps >> in >> your namespace. > > Just tried this. Its not the nicest, and it doubles the number of > namespaces in action for each sandbox, but it does work.
How much overhead is involved in each user namespace? Is there any system-wide limit on total namespaces, other than RAM? Is there (non-negligible) CPU overhead for each syscall seeking permissions in the namespace?
-Kenton
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