| Message ID | 20190820001805.241928-17-matthewgarrett@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add kernel lockdown functionality | expand |
On Tuesday, August 20, 2019 2:17:52 AM CEST Matthew Garrett wrote: > From: Linn Crosetto <lcrosetto@gmail.com> > > >From the kernel documentation (initrd_table_override.txt): > > If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible > to override nearly any ACPI table provided by the BIOS with an > instrumented, modified one. > > When lockdown is enabled, the kernel should disallow any unauthenticated > changes to kernel space. ACPI tables contain code invoked by the kernel, > so do not allow ACPI tables to be overridden if the kernel is locked down. > > Signed-off-by: Linn Crosetto <lcrosetto@gmail.com> > Signed-off-by: David Howells <dhowells@redhat.com> > Signed-off-by: Matthew Garrett <mjg59@google.com> > Reviewed-by: Kees Cook <keescook@chromium.org> > cc: linux-acpi@vger.kernel.org > Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/acpi/tables.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c > index de974322a197..b7c29a11c0c1 100644 > --- a/drivers/acpi/tables.c > +++ b/drivers/acpi/tables.c > @@ -20,6 +20,7 @@ > #include <linux/memblock.h> > #include <linux/earlycpio.h> > #include <linux/initrd.h> > +#include <linux/security.h> > #include "internal.h" > > #ifdef CONFIG_ACPI_CUSTOM_DSDT > @@ -577,6 +578,11 @@ void __init acpi_table_upgrade(void) > if (table_nr == 0) > return; > > + if (security_locked_down(LOCKDOWN_ACPI_TABLES)) { > + pr_notice("kernel is locked down, ignoring table override\n"); > + return; > + } > + > acpi_tables_addr = > memblock_find_in_range(0, ACPI_TABLE_UPGRADE_MAX_PHYS, > all_tables_size, PAGE_SIZE); >
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c index de974322a197..b7c29a11c0c1 100644 --- a/drivers/acpi/tables.c +++ b/drivers/acpi/tables.c @@ -20,6 +20,7 @@ #include <linux/memblock.h> #include <linux/earlycpio.h> #include <linux/initrd.h> +#include <linux/security.h> #include "internal.h" #ifdef CONFIG_ACPI_CUSTOM_DSDT @@ -577,6 +578,11 @@ void __init acpi_table_upgrade(void) if (table_nr == 0) return; + if (security_locked_down(LOCKDOWN_ACPI_TABLES)) { + pr_notice("kernel is locked down, ignoring table override\n"); + return; + } + acpi_tables_addr = memblock_find_in_range(0, ACPI_TABLE_UPGRADE_MAX_PHYS, all_tables_size, PAGE_SIZE);