From: Lee Jones <lee.jones@linaro.org>
To: lee.jones@linaro.org
Cc: linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org
Subject: [PATCH 1/1] cgroup-v1: Grant CAP_SYS_NICE holders permission to move tasks between cgroups
Date: Thu, 17 Jun 2021 10:09:41 +0100 [thread overview]
Message-ID: <20210617090941.340135-1-lee.jones@linaro.org> (raw)
It should be possible for processes with CAP_SYS_NICE capabilities
(privileges) to move lower priority tasks within the same namespace to
different cgroups.
One extremely common example of this is Android's 'system_server',
which moves processes around to different cgroups/cpusets, but should
not require any other root privileges.
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
kernel/cgroup/cgroup-v1.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 1f274d7fc934e..56d0d91951f02 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -510,7 +510,8 @@ static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of,
tcred = get_task_cred(task);
if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
!uid_eq(cred->euid, tcred->uid) &&
- !uid_eq(cred->euid, tcred->suid))
+ !uid_eq(cred->euid, tcred->suid) &&
+ !ns_capable(tcred->user_ns, CAP_SYS_NICE))
ret = -EACCES;
put_cred(tcred);
if (ret)
--
2.32.0
next reply other threads:[~2021-06-17 9:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 9:09 Lee Jones [this message]
2021-06-17 11:41 ` [PATCH 1/1] cgroup-v1: Grant CAP_SYS_NICE holders permission to move tasks between cgroups Tejun Heo
2021-06-17 12:01 ` Lee Jones
2021-09-30 21:20 ` Suren Baghdasaryan
2021-10-04 16:41 ` Tejun Heo
2021-10-04 16:57 ` Suren Baghdasaryan
2021-10-04 17:23 ` John Stultz
2021-10-04 17:33 ` John Stultz
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