userns: security: make capabilities relative to the user namespace

[cascardo/linux.git] / kernel / capability.c

diff --git a/kernel/capability.c b/kernel/capability.c
index 9e9385f..0a3d2c8 100644 (file)
--- 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);