On Wed, Jan 25, 2023 at 03:36:42PM -0800, Andrew Morton wrote: > On Wed, 25 Jan 2023 16:28:49 +0100 Alexey Gladkov <legion@xxxxxxxxxx> wrote: > > > If, after creating a container and mounting procfs, the system > > configuration may change and new files may appear in procfs. Files > > including writable root or any other users. > > > > In most cases, it is known in advance which files in procfs the user > > needs in the container. It is much easier to control the list of what > > you want than to control the list of unwanted files. > > > > To do this, subset=allowlist is added to control the visibility of > > static files in procfs (not process pids). After that, the control file > > /proc/allowlist appears in the root of the filesystem. This file > > contains a list of files and directories that will be visible in this > > vmountpoint. Immediately after mount, this file contains only one > > name - the name of the file itself. > > > > The admin can add names, read this file to get the current state of the > > allowlist. The file behaves almost like a regular file. Changes are > > applied when the file is closed. > > "the admin" is a bit vague. Precisely which capabilities are required > for this? In this commit, the admin is the one with CAP_SYS_ADMIN. You're right, I'll fix the commit message. > > To prevent changes to allowlist, admin should remove its name from the > > list of allowed files. After this change, the file will disappear. > -- Rgrds, legion
