Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[firefly-linux-kernel-4.4.55.git] / drivers / misc / lkdtm.c

diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index b5abe34120b8a9c2169e6bb8513e88bd8d49051c..11fdadc68e53e57722b4d58892fdf2c644beba34 100644 (file)
--- a/drivers/misc/lkdtm.c
+++ b/drivers/misc/lkdtm.c
@@ -472,7 +472,7 @@ static void lkdtm_do_action(enum ctype which)
                break;
        }
        case CT_ACCESS_USERSPACE: {
-               unsigned long user_addr, tmp;
+               unsigned long user_addr, tmp = 0;
                unsigned long *ptr;
 
                user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
@@ -483,6 +483,12 @@ static void lkdtm_do_action(enum ctype which)
                        return;
                }
 
+               if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) {
+                       pr_warn("copy_to_user failed\n");
+                       vm_munmap(user_addr, PAGE_SIZE);
+                       return;
+               }
+
                ptr = (unsigned long *)user_addr;
 
                pr_info("attempting bad read at %p\n", ptr);