diff options
| author | Colin Cross <ccross@android.com> | 2011-07-12 19:53:24 -0700 |
|---|---|---|
| committer | Arve Hjønnevåg <arve@android.com> | 2013-07-01 13:38:49 -0700 |
| commit | bebadf46e98874f1a18f2bcae73248ede371795b (patch) | |
| tree | 44c9197b607a0be217a9ad909163f641f8344c82 /kernel/sched | |
| parent | b4ef696dc1fc4f5c2a8bfa84dde2586e9a652e23 (diff) | |
cgroup: Add generic cgroup subsystem permission checks
Rather than using explicit euid == 0 checks when trying to move
tasks into a cgroup via CFS, move permission checks into each
specific cgroup subsystem. If a subsystem does not specify a
'allow_attach' handler, then we fall back to doing our checks
the old way.
Use the 'allow_attach' handler for the 'cpu' cgroup to allow
non-root processes to add arbitrary processes to a 'cpu' cgroup
if it has the CAP_SYS_NICE capability set.
This version of the patch adds a 'allow_attach' handler instead
of reusing the 'can_attach' handler. If the 'can_attach' handler
is reused, a new cgroup that implements 'can_attach' but not
the permission checks could end up with no permission checks
at all.
Change-Id: Icfa950aa9321d1ceba362061d32dc7dfa2c64f0c
Original-Author: San Mehat <san@google.com>
Signed-off-by: Colin Cross <ccross@android.com>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5b582cabd316..014040fa3d21 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7716,6 +7716,23 @@ static void cpu_cgroup_css_offline(struct cgroup *cgrp) sched_offline_group(tg); } +static int +cpu_cgroup_allow_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) +{ + const struct cred *cred = current_cred(), *tcred; + struct task_struct *task; + + cgroup_taskset_for_each(task, cgrp, tset) { + tcred = __task_cred(task); + + if ((current != task) && !capable(CAP_SYS_NICE) && + cred->euid != tcred->uid && cred->euid != tcred->suid) + return -EACCES; + } + + return 0; +} + static int cpu_cgroup_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) { @@ -8075,6 +8092,7 @@ struct cgroup_subsys cpu_cgroup_subsys = { .css_offline = cpu_cgroup_css_offline, .can_attach = cpu_cgroup_can_attach, .attach = cpu_cgroup_attach, + .allow_attach = cpu_cgroup_allow_attach, .exit = cpu_cgroup_exit, .subsys_id = cpu_cgroup_subsys_id, .base_cftypes = cpu_files, |