capabilities: allow nice if we are privileged

f54fb863 · Serge Hallyn <[email protected]> · 2013-07-23 13:18:53 -05:00

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 <[email protected]>
Reviewed-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>

Commit: f54fb863c6bbcbafdfc332b4a4260abb5a002137
Parents: 6e556ce2

Changes

1 files changed · +4 −4

File	Status	Add	Del	Content
security/commoncap.c	modified	+4	−4	View file

security/commoncap.c

View file

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 @@ int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
  */
 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;
 }
 
 /**