This is a revival of an older patch set from Dmitry Torokhov: https://lore.kernel.org/lkml/1471386795-32918-1-git-send-email-dmitry.torokhov@xxxxxxxxx/ Here's Dmitry's description: There are objects in /sys hierarchy (/sys/class/net/) that logically belong to a namespace/container. Unfortunately all sysfs objects start their life belonging to global root, and while we could change ownership manually, keeping tracks of all objects that come and go is cumbersome. It would be better if kernel created them using correct uid/gid from the beginning. This series changes kernfs to allow creating object's with arbitrary uid/gid, adds get_ownership() callback to ktype structure so subsystems could supply their own logic (likely tied to namespace support) for determining ownership of kobjects, and adjusts sysfs code to make use of this information. Lastly net-sysfs is adjusted to make sure that objects in net namespace are owned by the root user from the owning user namespace. Note that we do not adjust ownership of objects moved into a new namespace (as when moving a network device into a container) as userspace can easily do it. I'm reviving this patch set because we would like this feature for system containers. One specific use case that we have is that libvirt is unable to configure its bridge device inside of a system container due to the bridge files in /sys/class/net/ being owned by init root instead of container root. The last two patches in this set are patches that I've added to Dmitry's original set to allow such configuration of the bridge device. Eric had previously provided feedback that he didn't favor these changes affecting all layers of the stack and that most of the changes could remain local to drivers/base/core.c. That feedback is certainly sensible but I wanted to send out v2 of the patch set without making that large of a change since quite a bit of time has passed and the bridge changes in the last patch of this set shows that not all of the changes will be local to drivers/base/core.c. I'm happy to make the changes if the original request still stands. I've verified that all of the bridge related files affected by patch 7 have proper access control checks for CAP_NET_ADMIN inside of the user namespace. I have *not* yet verified that all of the network device related sysfs files affected by patch 5 have proper access control checks. I was working under the assumption that those code paths already were verified when the first iteration of the patches were sent out. * Changes since v1: - Patch 1 was forward ported to use idr instead of ida for the inode num - Patch 5 was forward ported around the ro_after_init changes - Patch 5 received a build failure fix for !CONFIG_SYSFS - Patch 6 and 7 are new Thanks! Tyler _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
