futex: move user address verification up to common code

[~andy/linux] / kernel / futex.c

diff --git a/kernel/futex.c b/kernel/futex.c
index 02febad007944ca0ff7eaf4880df7f8e06f5972c..f6ff0191ecf72aca1d42f128771af55f9c859d13 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -251,6 +251,9 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
                return -EINVAL;
        address -= key->both.offset;
 
+       if (unlikely(!access_ok(rw, uaddr, sizeof(u32))))
+               return -EFAULT;
+
        /*
         * PROCESS_PRIVATE futexes are fast.
         * As the mm cannot disappear under us and the 'key' only needs
@@ -259,8 +262,6 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
         *        but access_ok() should be faster than find_vma()
         */
        if (!fshared) {
-               if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
-                       return -EFAULT;
                key->private.mm = mm;
                key->private.address = address;
                get_futex_key_refs(key);