diff options
| author |   Chen Ridong <chenridong@huawei.com> | 2024-08-15 13:14:08 +0000 |
|---|---|---|
| committer |   Tejun Heo <tj@kernel.org> | 2024-08-19 12:16:17 -1000 |
| commit | d1a92d2d6c5dbeba9a87bfb57fa0142cdae7b206 (patch) | |
| tree | 60ae9c0a7c40540ebcb47b3d6ac9e3f9115f011a | |
| parent | cgroup: Fix incorrect WARN_ON_ONCE() in css_release_work_fn() (diff) | |
| download | wireguard-linux-d1a92d2d6c5dbeba9a87bfb57fa0142cdae7b206.tar.xz wireguard-linux-d1a92d2d6c5dbeba9a87bfb57fa0142cdae7b206.zip | |
cgroup: update some statememt about delegation
The comment in cgroup_file_write is missing some interfaces, such as
'cgroup.threads'. All delegatable files are listed in
'/sys/kernel/cgroup/delegate', so update the comment in cgroup_file_write.
Besides, add a statement that files outside the namespace shouldn't be
visible from inside the delegated namespace.
tj: Reflowed text for consistency.
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 10 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup.c | 2 |
2 files changed, 7 insertions, 5 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 70cefccd07ce..75f8c403f77a 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -533,10 +533,12 @@ cgroup namespace on namespace creation. Because the resource control interface files in a given directory control the distribution of the parent's resources, the delegatee shouldn't be allowed to write to them. For the first method, this is -achieved by not granting access to these files. For the second, the -kernel rejects writes to all files other than "cgroup.procs" and -"cgroup.subtree_control" on a namespace root from inside the -namespace. +achieved by not granting access to these files. For the second, files +outside the namespace should be hidden from the delegatee by the means +of at least mount namespacing, and the kernel rejects writes to all +files on a namespace root from inside the cgroup namespace, except for +those files listed in "/sys/kernel/cgroup/delegate" (including +"cgroup.procs", "cgroup.threads", "cgroup.subtree_control", etc.). The end results are equivalent for both delegation types. Once delegated, the user can build sub-hierarchy under the directory, diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 244ec600b4d8..c72e18ffbfd8 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4124,7 +4124,7 @@ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf, * If namespaces are delegation boundaries, disallow writes to * files in an non-init namespace root from inside the namespace * except for the files explicitly marked delegatable - - * cgroup.procs and cgroup.subtree_control. + * eg. cgroup.procs, cgroup.threads and cgroup.subtree_control. */ if ((cgrp->root->flags & CGRP_ROOT_NS_DELEGATE) && !(cft->flags & CFTYPE_NS_DELEGATABLE) && |