From: Javier Martinez Canillas <javi...@redhat.com> There are some more commands that should be restricted when the GRUB is locked down. Following is the list of commands and reasons to restrict:
* fakebios: creates BIOS-like structures for backward compatibility with existing OSes. This should not be allowed when locked down. * loadbios: reads a BIOS dump from storage and loads it. This action should not be allowed when locked down. * devicetree: loads a Device Tree blob and passes it to the OS. It replaces any Device Tree provided by the firmware. This also should not be allowed when locked down. Signed-off-by: Javier Martinez Canillas <javi...@redhat.com> Reviewed-by: Daniel Kiper <daniel.ki...@oracle.com> --- docs/grub.texi | 3 +++ grub-core/commands/efi/loadbios.c | 14 +++++++------- grub-core/loader/arm/linux.c | 6 +++--- grub-core/loader/efi/fdt.c | 4 ++-- 4 files changed, 15 insertions(+), 12 deletions(-) diff --git a/docs/grub.texi b/docs/grub.texi index 5dbb02f1c..91666781b 100644 --- a/docs/grub.texi +++ b/docs/grub.texi @@ -4324,6 +4324,9 @@ hour, minute, and second unchanged. Load a device tree blob (.dtb) from a filesystem, for later use by a Linux kernel. Does not perform merging with any device tree supplied by firmware, but rather replaces it completely. + +Note: The command is not allowed when lockdown is enforced (@pxref{Lockdown}). + This is done to prevent subverting various security mechanisms. @end deffn @node distrust diff --git a/grub-core/commands/efi/loadbios.c b/grub-core/commands/efi/loadbios.c index d41d521a4..5c7725f8b 100644 --- a/grub-core/commands/efi/loadbios.c +++ b/grub-core/commands/efi/loadbios.c @@ -205,14 +205,14 @@ static grub_command_t cmd_fakebios, cmd_loadbios; GRUB_MOD_INIT(loadbios) { - cmd_fakebios = grub_register_command ("fakebios", grub_cmd_fakebios, - 0, N_("Create BIOS-like structures for" - " backward compatibility with" - " existing OS.")); + cmd_fakebios = grub_register_command_lockdown ("fakebios", grub_cmd_fakebios, + 0, N_("Create BIOS-like structures for" + " backward compatibility with" + " existing OS.")); - cmd_loadbios = grub_register_command ("loadbios", grub_cmd_loadbios, - N_("BIOS_DUMP [INT10_DUMP]"), - N_("Load BIOS dump.")); + cmd_loadbios = grub_register_command_lockdown ("loadbios", grub_cmd_loadbios, + N_("BIOS_DUMP [INT10_DUMP]"), + N_("Load BIOS dump.")); } GRUB_MOD_FINI(loadbios) diff --git a/grub-core/loader/arm/linux.c b/grub-core/loader/arm/linux.c index d70c17486..ed23dc71e 100644 --- a/grub-core/loader/arm/linux.c +++ b/grub-core/loader/arm/linux.c @@ -493,9 +493,9 @@ GRUB_MOD_INIT (linux) 0, N_("Load Linux.")); cmd_initrd = grub_register_command ("initrd", grub_cmd_initrd, 0, N_("Load initrd.")); - cmd_devicetree = grub_register_command ("devicetree", grub_cmd_devicetree, - /* TRANSLATORS: DTB stands for device tree blob. */ - 0, N_("Load DTB file.")); + cmd_devicetree = grub_register_command_lockdown ("devicetree", grub_cmd_devicetree, + /* TRANSLATORS: DTB stands for device tree blob. */ + 0, N_("Load DTB file.")); my_mod = mod; current_fdt = (const void *) grub_arm_firmware_get_boot_data (); machine_type = grub_arm_firmware_get_machine_type (); diff --git a/grub-core/loader/efi/fdt.c b/grub-core/loader/efi/fdt.c index ee9c5592c..003d07cd8 100644 --- a/grub-core/loader/efi/fdt.c +++ b/grub-core/loader/efi/fdt.c @@ -165,8 +165,8 @@ static grub_command_t cmd_devicetree; GRUB_MOD_INIT (fdt) { cmd_devicetree = - grub_register_command ("devicetree", grub_cmd_devicetree, 0, - N_("Load DTB file.")); + grub_register_command_lockdown ("devicetree", grub_cmd_devicetree, 0, + N_("Load DTB file.")); } GRUB_MOD_FINI (fdt) -- 2.11.0 _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel