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-rw-r--r--include/linux/cgroup.h4
-rw-r--r--kernel/cgroup.c11
-rw-r--r--kernel/ns_cgroup.c14
3 files changed, 12 insertions, 17 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index bb8feb9..788c496 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -348,8 +348,8 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
int cgroup_task_count(const struct cgroup *cgrp);
-/* Return true if the cgroup is a descendant of the current cgroup */
-int cgroup_is_descendant(const struct cgroup *cgrp);
+/* Return true if cgrp is a descendant of the task's cgroup */
+int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task);
/* Control Group subsystem type. See Documentation/cgroups.txt for details */
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c500ca7..27792bc 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3084,18 +3084,19 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
}
/**
- * cgroup_is_descendant - see if @cgrp is a descendant of current task's cgrp
+ * cgroup_is_descendant - see if @cgrp is a descendant of @task's cgrp
* @cgrp: the cgroup in question
+ * @task: the task in question
*
- * See if @cgrp is a descendant of the current task's cgroup in
- * the appropriate hierarchy.
+ * See if @cgrp is a descendant of @task's cgroup in the appropriate
+ * hierarchy.
*
* If we are sending in dummytop, then presumably we are creating
* the top cgroup in the subsystem.
*
* Called only by the ns (nsproxy) cgroup.
*/
-int cgroup_is_descendant(const struct cgroup *cgrp)
+int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task)
{
int ret;
struct cgroup *target;
@@ -3105,7 +3106,7 @@ int cgroup_is_descendant(const struct cgroup *cgrp)
return 1;
get_first_subsys(cgrp, NULL, &subsys_id);
- target = task_cgroup(current, subsys_id);
+ target = task_cgroup(task, subsys_id);
while (cgrp != target && cgrp!= cgrp->top_cgroup)
cgrp = cgrp->parent;
ret = (cgrp == target);
diff --git a/kernel/ns_cgroup.c b/kernel/ns_cgroup.c
index 78bc3fd..5aa854f 100644
--- a/kernel/ns_cgroup.c
+++ b/kernel/ns_cgroup.c
@@ -34,7 +34,7 @@ int ns_cgroup_clone(struct task_struct *task, struct pid *pid)
/*
* Rules:
- * 1. you can only enter a cgroup which is a child of your current
+ * 1. you can only enter a cgroup which is a descendant of your current
* cgroup
* 2. you can only place another process into a cgroup if
* a. you have CAP_SYS_ADMIN
@@ -45,21 +45,15 @@ int ns_cgroup_clone(struct task_struct *task, struct pid *pid)
static int ns_can_attach(struct cgroup_subsys *ss,
struct cgroup *new_cgroup, struct task_struct *task)
{
- struct cgroup *orig;
-
if (current != task) {
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (!cgroup_is_descendant(new_cgroup))
+ if (!cgroup_is_descendant(new_cgroup, current))
return -EPERM;
}
- if (atomic_read(&new_cgroup->count) != 0)
- return -EPERM;
-
- orig = task_cgroup(task, ns_subsys_id);
- if (orig && orig != new_cgroup->parent)
+ if (!cgroup_is_descendant(new_cgroup, task))
return -EPERM;
return 0;
@@ -77,7 +71,7 @@ static struct cgroup_subsys_state *ns_create(struct cgroup_subsys *ss,
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
- if (!cgroup_is_descendant(cgroup))
+ if (!cgroup_is_descendant(cgroup, current))
return ERR_PTR(-EPERM);
ns_cgroup = kzalloc(sizeof(*ns_cgroup), GFP_KERNEL);
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