1 files changed, 37 insertions, 5 deletions

diff --git a/kernel/capability.c b/kernel/capability.c
index 9e9385f132c..0a3d2c863a1 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -14,6 +14,7 @@
 #include <linux/security.h>
 #include <linux/syscalls.h>
 #include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
 #include <asm/uaccess.h>
 
 /*
@@ -299,17 +300,48 @@ error:
  * This sets PF_SUPERPRIV on the task if the capability is available on the
  * assumption that it's about to be used.
  */
-int capable(int cap)
+bool capable(int cap)
+{
+        return ns_capable(&init_user_ns, cap);
+}
+EXPORT_SYMBOL(capable);
+
+/**
+ * ns_capable - Determine if the current task has a superior capability in effect
+ * @ns:  The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool ns_capable(struct user_namespace *ns, int cap)
 {
         if (unlikely(!cap_valid(cap))) {
                 printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
                 BUG();
         }
 
-        if (security_capable(current_cred(), cap) == 0) {
+        if (security_capable(ns, current_cred(), cap) == 0) {
                 current->flags |= PF_SUPERPRIV;
-                return 1;
+                return true;
         }
-        return 0;
+        return false;
 }
-EXPORT_SYMBOL(capable);
+EXPORT_SYMBOL(ns_capable);
+
+/**
+ * task_ns_capable - Determine whether current task has a superior
+ * capability targeted at a specific task's user namespace.
+ * @t: The task whose user namespace is targeted.
+ * @cap: The capability in question.
+ *
+ *  Return true if it does, false otherwise.
+ */
+bool task_ns_capable(struct task_struct *t, int cap)
+{
+        return ns_capable(task_cred_xxx(t, user)->user_ns, cap);
+}
+EXPORT_SYMBOL(task_ns_capable);