LSM: LoadPin: provide enablement CONFIG
Instead of being enabled by default when SECURITY_LOADPIN is selected,
provide an additional (default off) config to determine the boot time
behavior. As before, the "loadpin.enabled=0/1" kernel parameter remains
available.
Suggested-by: James Morris <jmorris@namei.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
diff --git a/security/loadpin/Kconfig b/security/loadpin/Kconfig
index c668ac4..dd01aa9 100644
--- a/security/loadpin/Kconfig
+++ b/security/loadpin/Kconfig
@@ -3,8 +3,17 @@
depends on SECURITY && BLOCK
help
Any files read through the kernel file reading interface
- (kernel modules, firmware, kexec images, security policy) will
- be pinned to the first filesystem used for loading. Any files
- that come from other filesystems will be rejected. This is best
- used on systems without an initrd that have a root filesystem
- backed by a read-only device such as dm-verity or a CDROM.
+ (kernel modules, firmware, kexec images, security policy)
+ can be pinned to the first filesystem used for loading. When
+ enabled, any files that come from other filesystems will be
+ rejected. This is best used on systems without an initrd that
+ have a root filesystem backed by a read-only device such as
+ dm-verity or a CDROM.
+
+config SECURITY_LOADPIN_ENABLED
+ bool "Enforce LoadPin at boot"
+ depends on SECURITY_LOADPIN
+ help
+ If selected, LoadPin will enforce pinning at boot. If not
+ selected, it can be enabled at boot with the kernel parameter
+ "loadpin.enabled=1".
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index e4debae..89a46f1 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -45,7 +45,7 @@
kfree(pathname);
}
-static int enabled = 1;
+static int enabled = IS_ENABLED(CONFIG_SECURITY_LOADPIN_ENABLED);
static struct super_block *pinned_root;
static DEFINE_SPINLOCK(pinned_root_spinlock);