1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index 9725aed305bb..389475b25bb7 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -322,6 +322,19 @@ free_user:
         vm_munmap(user_addr, PAGE_SIZE);
 }
 
+void lkdtm_USERCOPY_KERNEL_DS(void)
+{
+        char __user *user_ptr = (char __user *)ERR_PTR(-EINVAL);
+        mm_segment_t old_fs = get_fs();
+        char buf[10] = {0};
+
+        pr_info("attempting copy_to_user on unmapped kernel address\n");
+        set_fs(KERNEL_DS);
+        if (copy_to_user(user_ptr, buf, sizeof(buf)))
+                pr_info("copy_to_user un unmapped kernel address failed\n");
+        set_fs(old_fs);
+}
+
 void __init lkdtm_usercopy_init(void)
 {
         /* Prepare cache that lacks SLAB_USERCOPY flag. */