1 files changed, 9 insertions, 6 deletions

diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index 34684adb6899..b3b09b98896d 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -46,6 +46,15 @@ extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 static inline
 bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
 {
+        /*
+         * "Allocated" pkeys are those that have been returned
+         * from pkey_alloc().  pkey 0 is special, and never
+         * returned from pkey_alloc().
+         */
+        if (pkey <= 0)
+                return false;
+        if (pkey >= arch_max_pkey())
+                return false;
         return mm_pkey_allocation_map(mm) & (1U << pkey);
 }
 
@@ -82,12 +91,6 @@ int mm_pkey_alloc(struct mm_struct *mm)
 static inline
 int mm_pkey_free(struct mm_struct *mm, int pkey)
 {
-        /*
-         * pkey 0 is special, always allocated and can never
-         * be freed.
-         */
-        if (!pkey)
-                return -EINVAL;
         if (!mm_pkey_is_allocated(mm, pkey))
                 return -EINVAL;