diff options
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r-- | kernel/cgroup.c | 53 |
1 files changed, 50 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 18711f326260..a822ed2a6de1 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2110,6 +2110,44 @@ out_free_group_list: return retval; } +static int cgroup_allow_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) +{ + struct cgroup_subsys_state *css; + int i; + int ret; + + for_each_css(css, i, cgrp) { + if (css->ss->allow_attach) { + ret = css->ss->allow_attach(css, tset); + if (ret) + return ret; + } else { + return -EACCES; + } + } + + return 0; +} + +int subsys_cgroup_allow_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) +{ + const struct cred *cred = current_cred(), *tcred; + struct task_struct *task; + + if (capable(CAP_SYS_NICE)) + return 0; + + cgroup_taskset_for_each(task, css, tset) { + tcred = __task_cred(task); + + if (current != task && !uid_eq(cred->euid, tcred->uid) && + !uid_eq(cred->euid, tcred->suid)) + return -EACCES; + } + + return 0; +} + /* * Find the task_struct of the task to attach by vpid and pass it along to the * function to attach either it or all tasks in its threadgroup. Will lock @@ -2141,9 +2179,18 @@ retry_find_task: if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) && !uid_eq(cred->euid, tcred->uid) && !uid_eq(cred->euid, tcred->suid)) { - rcu_read_unlock(); - ret = -EACCES; - goto out_unlock_cgroup; + /* + * if the default permission check fails, give each + * cgroup a chance to extend the permission check + */ + struct cgroup_taskset tset = { }; + tset.single.task = tsk; + tset.single.cgrp = cgrp; + ret = cgroup_allow_attach(cgrp, &tset); + if (ret) { + rcu_read_unlock(); + goto out_unlock_cgroup; + } } } else tsk = current; |