capabilities: allow nice if we are privileged
We allow task A to change B's nice level if it has a supserset of
B's privileges, or of it has CAP_SYS_NICE. Also allow it if A has
CAP_SYS_NICE with respect to B - meaning it is root in the same
namespace, or it created B's namespace.
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/security/commoncap.c b/security/commoncap.c
index 9fccf71..b9d613e 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -768,16 +768,16 @@
*/
static int cap_safe_nice(struct task_struct *p)
{
- int is_subset;
+ int is_subset, ret = 0;
rcu_read_lock();
is_subset = cap_issubset(__task_cred(p)->cap_permitted,
current_cred()->cap_permitted);
+ if (!is_subset && !ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE))
+ ret = -EPERM;
rcu_read_unlock();
- if (!is_subset && !capable(CAP_SYS_NICE))
- return -EPERM;
- return 0;
+ return ret;
}
/**
