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Kernel 4.14.74 enabled user namespaces

October 08, 2018 — BarryK

The 4.14.73 kernel was compiled only a few days ago:

It has namespaces support, all except user namespaces. Coz I had read various reports about user namespaces being trouble.

However, want to explore user namespace in containers, so have now enabled it in the compile of the 4.14.74 kernel. That is the only configuration difference.

General setup
 Namespaces support
[*] User namespaces

With so much happening, should think about getting out the next Easy, version 0.9.7, soon.

EDIT 2018-10-8
Reverted, going back to the 4.14.73 kernel with user namespaces disabled. Will keep it disabled for future compiles of the kernel. Have been reading some more, and user namespaces seem like asking for trouble. Plus, as already running as root in Easy, there doesn't seem much point in having user namespaces.

What I do want to be able to do is optionally run as user 'zeus' in containers. I was unable to get pflask to do that. rather than get tied up trying to "fix" pflask, perhaps this is a satisfactory workaround:

# pflask -- chroot --userspec=zeus:zeus /mnt/sdc2/containers/sh0/container whoami

Well, that's a starting point, but has limitations. If pflask drops capabilities, will have to make sure that still has the capability to do a chroot and change user:group -- which, oddly, may mean zeus will end up with more capabilities than the "crippled root" -- though, a start-script in the container could drop more capabilities.

Also, the full 'chroot' from 'coreutils' package is required, as the busybox applet does not support that commandline option.

Tags: easy