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There is a potential Denial of Service attack from a container against the host by using up 50% of available memory from writing to /dev.

Also needs to be fixed in Fedora.

This is really under docker.  But I am not sure it is real important.  Since /tmp size is controlled by memory cgroup, this would only allow a user to use 50% of available memory in his container.  If the admin does not set any memory limit on a container the processes inside could use 100% or memory.

Created attachment 1300623 [details]
This patch might fix the issue.

Yeah, that should work. Do we want to make it configurable though like the --shm-size flag in docker?

I don't think it would ever grow to that big of a size unless the user is doing something very wrong, the only things that should be in /dev are devicenodes.

Giving a container with a tmpfs limited with size makes sense.

We have no plans to ship another version of Docker at this time. RHEL7 is in final support stages where only security fixes will get released.  Customers should move to use Podman which is available starting in RHEL 7.6.