vt_ioctl: return -EFAULT on copy_from_user errors

copy_from_user() returns the number of bytes remaining but we want to
return a negative error code here.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c
index 6aa10284104a..cb19dbc52136 100644
--- a/drivers/char/vt_ioctl.c
+++ b/drivers/char/vt_ioctl.c
@@ -1303,7 +1303,9 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
                 if (!perm)
                         goto eperm;
                 ret = copy_from_user(&ui, up, sizeof(struct unimapinit));
-                if (!ret)
+                if (ret)
+                        ret = -EFAULT;
+                else
                         con_clear_unimap(vc, &ui);
                 break;
               }