grub2: CVE-2021-3981 Incorrect permission in grub.cfg allow unprivileged user to...

grub2: CVE-2021-3981 Incorrect permission in grub.cfg allow unprivileged user to read the file content

Source: https://git.savannah.gnu.org/cgit/grub.git/
MR: 116495
Type: Security Fix
Disposition: Backport from https://git.savannah.gnu.org/cgit/grub.git/diff/util/grub-mkconfig.in?id=0adec29674561034771c13e446069b41ef41e4d4
ChangeID: fce3d59e50320bef247bb981352051b8f953a4fc
Description:
        CVE-2021-3981 grub2: Incorrect permission in grub.cfg allow unprivileged user to read the file content.

Affects "grub2 < 2.06"

Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>