diff options
| author | Christian Brauner <christian.brauner@ubuntu.com> | 2020-02-05 14:26:18 +0100 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2020-02-12 17:57:51 -0500 |
| commit | 6df970e4f5d2c273554550d40d8b92cea9bec1a0 (patch) | |
| tree | a7734ff12f7dbb720c60a80c4b4519cb2d6b2809 | |
| parent | a49e4629b5edf1db856de05fbf1aae05502ef1af (diff) | |
cgroup: unify attach permission checking
The core codepaths to check whether a process can be attached to a
cgroup are the same for threads and thread-group leaders. Only a small
piece of code verifying that source and destination cgroup are in the
same domain differentiates the thread permission checking from
thread-group leader permission checking.
Since cgroup_migrate_vet_dst() only matters cgroup2 - it is a noop on
cgroup1 - we can move it out of cgroup_attach_task().
All checks can now be consolidated into a new helper
cgroup_attach_permissions() callable from both cgroup_procs_write() and
cgroup_threads_write().
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | kernel/cgroup/cgroup.c | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 7a310db6c807..9ca51bf3769a 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2714,11 +2714,7 @@ int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, { DEFINE_CGROUP_MGCTX(mgctx); struct task_struct *task; - int ret; - - ret = cgroup_migrate_vet_dst(dst_cgrp); - if (ret) - return ret; + int ret = 0; /* look up all src csets */ spin_lock_irq(&css_set_lock); @@ -4695,6 +4691,26 @@ static int cgroup_procs_write_permission(struct cgroup *src_cgrp, return 0; } +static int cgroup_attach_permissions(struct cgroup *src_cgrp, + struct cgroup *dst_cgrp, + struct super_block *sb, bool threadgroup) +{ + int ret = 0; + + ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp, sb); + if (ret) + return ret; + + ret = cgroup_migrate_vet_dst(dst_cgrp); + if (ret) + return ret; + + if (!threadgroup && (src_cgrp->dom_cgrp != dst_cgrp->dom_cgrp)) + ret = -EOPNOTSUPP; + + return ret; +} + static ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { @@ -4717,8 +4733,8 @@ static ssize_t cgroup_procs_write(struct kernfs_open_file *of, src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root); spin_unlock_irq(&css_set_lock); - ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp, - of->file->f_path.dentry->d_sb); + ret = cgroup_attach_permissions(src_cgrp, dst_cgrp, + of->file->f_path.dentry->d_sb, true); if (ret) goto out_finish; @@ -4762,16 +4778,11 @@ static ssize_t cgroup_threads_write(struct kernfs_open_file *of, spin_unlock_irq(&css_set_lock); /* thread migrations follow the cgroup.procs delegation rule */ - ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp, - of->file->f_path.dentry->d_sb); + ret = cgroup_attach_permissions(src_cgrp, dst_cgrp, + of->file->f_path.dentry->d_sb, false); if (ret) goto out_finish; - /* and must be contained in the same domain */ - ret = -EOPNOTSUPP; - if (src_cgrp->dom_cgrp != dst_cgrp->dom_cgrp) - goto out_finish; - ret = cgroup_attach_task(dst_cgrp, task, false); out_finish: |