Since commit: ab2e53c8a grub-mkconfig: Honor a symlink when generating configuration by grub-mkconfig
has inadvertently discarded umask for creating grub.cfg in the process of grub-mkconfig. The resulting wrong permission (0644) would allow unprivileged users to read grub's configuration file content. This presents a low confidentiality risk as grub.cfg may contain non-secured plain-text passwords. This patch restores the missing umask and set the file mode of creation to 0600 preventing unprivileged access. Fixes: CVE-2021-3981 Signed-off-by: Michael Chang <mch...@suse.com> --- util/grub-mkconfig.in | 2 ++ 1 file changed, 2 insertions(+) diff --git a/util/grub-mkconfig.in b/util/grub-mkconfig.in index c3ea7612e..41af98135 100644 --- a/util/grub-mkconfig.in +++ b/util/grub-mkconfig.in @@ -301,7 +301,9 @@ and /etc/grub.d/* files or please file a bug report with exit 1 else # none of the children aborted with error, install the new grub.cfg + oldumask=$(umask); umask 077 cat ${grub_cfg}.new > ${grub_cfg} + umask $oldumask rm -f ${grub_cfg}.new fi fi -- 2.31.1 _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel