On 29 January 2016 at 09:54, <serge.hallyn@xxxxxxxxxx> wrote: > Hi, > > following is a revised set of the CGroup Namespace patchset which Aditya > Kali has previously sent. The code can also be found in the cgroupns.v10 > branch of > > https://git.kernel.org/cgit/linux/kernel/git/sergeh/linux-security.git/ > > To summarize the semantics: > > 1. CLONE_NEWCGROUP re-uses 0x02000000, which was previously CLONE_STOPPED > > 2. unsharing a cgroup namespace makes all your current cgroups your new > cgroup root. > > 3. /proc/pid/cgroup always shows cgroup paths relative to the reader's > cgroup namespce root. A task outside of your cgroup looks like > > 8:memory:/../../.. > > 4. when a task mounts a cgroupfs, the cgroup which shows up as root depends > on the mounting task's cgroup namespace. > > 5. setns to a cgroup namespace switches your cgroup namespace but not > your cgroups. > > With this, using github.com/hallyn/lxc #2015-11-09/cgns (and > github.com/hallyn/lxcfs #2015-11-10/cgns) we can start a container in a full > proper cgroup namespace, avoiding either cgmanager or lxcfs cgroup bind mounts. > > This is completely backward compatible and will be completely invisible > to any existing cgroup users (except for those running inside a cgroup > namespace and looking at /proc/pid/cgroup of tasks outside their > namespace.) Hi, I just noticed commit c38c4597e4bf ("netfilter: implement xt_cgroup cgroup2 path match") which, as far as I understand, introduces a new userland facing API containing the full cgroup path. Does it mean that the cgroupns patchset should include cgroup path translation in xt_cgroup? > Changes from V9: > 1. Update to latest Linus tree > 2. A few locking fixes > > Changes from V8: > 1. Incorporate updated documentation from tj. > 2. Put lookup_one_len() under inode lock > 3. Make cgroup_path non-namespaced, so only calls to cgroup_path_ns() are > namespaced. > 4. Make cgroup_path{,_ns} take the needed locks, since external callers cannot > do so. > 5. Fix the bisectability problem of to_cg_ns() being defined after use > > Changes from V7: > 1. Rework kernfs_path_from_node_locked to return the string length > 2. Rename and reorder args to kernfs_path_from_node > 3. cgroup.c: undo accidental conversoins to inline > 4. cgroup.h: move ns declarations to bottom. > 5. Rework the documentation to fit the style of the rest of cgroup.txt > > Changes from V6: > 1. Switch to some WARN_ONs to provide stack traces > 2. Rename kernfs_node_distance to kernfs_depth > 3. Make sure kernfs_common_ancestor() nodes are from same root > 4. Split kernfs changes for cgroup_mount into separate patch > 5. Rename kernfs_obtain_root to kernfs_node_dentry > (And more, see patch changelogs) > > Changes from V5: > 1. To get a root dentry for cgroup namespace mount, walk the path from the > kernfs root dentry. > > Changes from V4: > 1. Move the FS_USERNS_MOUNT flag to last patch > 2. Rebase onto cgroup/for-4.5 > 3. Don't non-init user namespaces to bind new subsystems when mounting. > 4. Address feedback from Tejun (thanks). Specificaly, not addressed: > . kernfs_obtain_root - walking dentry from kernfs root. > (I think that's the only piece) > 5. Dropped unused get_task_cgroup fn/patch. > 6. Reworked kernfs_path_from_node_locked() to try to simplify the logic. > It now finds a common ancestor, walks from the source to it, then back > up to the target. > > Changes from V3: > 1. Rebased onto latest cgroup changes. In particular switch to > css_set_lock and ns_common. > 2. Support all hierarchies. > > Changes from V2: > 1. Added documentation in Documentation/cgroups/namespace.txt > 2. Fixed a bug that caused crash > 3. Incorporated some other suggestions from last patchset: > - removed use of threadgroup_lock() while creating new cgroupns > - use task_lock() instead of rcu_read_lock() while accessing > task->nsproxy > - optimized setns() to own cgroupns > - simplified code around sane-behavior mount option parsing > 4. Restored ACKs from Serge Hallyn from v1 on few patches that have > not changed since then. > > Changes from V1: > 1. No pinning of processes within cgroupns. Tasks can be freely moved > across cgroups even outside of their cgroupns-root. Usual DAC/MAC policies > apply as before. > 2. Path in /proc/<pid>/cgroup is now always shown and is relative to > cgroupns-root. So path can contain '/..' strings depending on cgroupns-root > of the reader and cgroup of <pid>. > 3. setns() does not require the process to first move under target > cgroupns-root. > > Changes form RFC (V0): > 1. setns support for cgroupns > 2. 'mount -t cgroup cgroup <mntpt>' from inside a cgroupns now > mounts the cgroup hierarcy with cgroupns-root as the filesystem root. > 3. writes to cgroup files outside of cgroupns-root are not allowed > 4. visibility of /proc/<pid>/cgroup is further restricted by not showing > anything if the <pid> is in a sibling cgroupns and its cgroup falls outside > your cgroupns-root. > > > _______________________________________________ > lxc-devel mailing list > lxc-devel@xxxxxxxxxxxxxxxxxxxxxxxxx > http://lists.linuxcontainers.org/listinfo/lxc-devel -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
