[RFC PATCH 2/9] Introduce a new LSM: loadpol

[Simon THOBY <git@nightmared.fr>]

Create a new LSM to filter the load of kernel modules according
to a user-provided policy.

Signed-off-by: Simon THOBY <git@nightmared.fr>
---
 include/linux/lsm_count.h  |  7 +++++++
 include/uapi/linux/lsm.h   |  1 +
 security/Kconfig           |  1 +
 security/Makefile          |  1 +
 security/loadpol/Kconfig   | 12 ++++++++++++
 security/loadpol/Makefile  |  1 +
 security/loadpol/loadpol.c | 29 +++++++++++++++++++++++++++++
 security/loadpol/loadpol.h |  8 ++++++++
 8 files changed, 60 insertions(+)
 create mode 100644 security/loadpol/Kconfig
 create mode 100644 security/loadpol/Makefile
 create mode 100644 security/loadpol/loadpol.c
 create mode 100644 security/loadpol/loadpol.h

diff --git a/include/linux/lsm_count.h b/include/linux/lsm_count.h
index 16eb49761b25..9e0d96dfe9d2 100644
--- a/include/linux/lsm_count.h
+++ b/include/linux/lsm_count.h
@@ -84,6 +84,12 @@
 #define LANDLOCK_ENABLED
 #endif
 
+#if IS_ENABLED(CONFIG_SECURITY_LOADPOL)
+#define LOADPOL_ENABLED 1,
+#else
+#define LOADPOL_ENABLED
+#endif
+
 #if IS_ENABLED(CONFIG_IMA)
 #define IMA_ENABLED 1,
 #else
@@ -122,6 +128,7 @@
 		SAFESETID_ENABLED	\
 		BPF_LSM_ENABLED		\
 		LANDLOCK_ENABLED	\
+		LOADPOL_ENABLED		\
 		IMA_ENABLED		\
 		EVM_ENABLED		\
 		IPE_ENABLED)
diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
index 938593dfd5da..ec8bdb415562 100644
--- a/include/uapi/linux/lsm.h
+++ b/include/uapi/linux/lsm.h
@@ -65,6 +65,7 @@ struct lsm_ctx {
 #define LSM_ID_IMA		111
 #define LSM_ID_EVM		112
 #define LSM_ID_IPE		113
+#define LSM_ID_LOADPOL		114
 
 /*
  * LSM_ATTR_XXX definitions identify different LSM attributes
diff --git a/security/Kconfig b/security/Kconfig
index 4816fc74f81e..e492c0d6768c 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -230,6 +230,7 @@ source "security/safesetid/Kconfig"
 source "security/lockdown/Kconfig"
 source "security/landlock/Kconfig"
 source "security/ipe/Kconfig"
+source "security/loadpol/Kconfig"
 
 source "security/integrity/Kconfig"
 
diff --git a/security/Makefile b/security/Makefile
index 22ff4c8bd8ce..562c572b7f23 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_CGROUPS)			+= device_cgroup.o
 obj-$(CONFIG_BPF_LSM)			+= bpf/
 obj-$(CONFIG_SECURITY_LANDLOCK)		+= landlock/
 obj-$(CONFIG_SECURITY_IPE)		+= ipe/
+obj-$(CONFIG_SECURITY_LOADPOL)		+= loadpol/
 
 # Object integrity file lists
 obj-$(CONFIG_INTEGRITY)			+= integrity/
diff --git a/security/loadpol/Kconfig b/security/loadpol/Kconfig
new file mode 100644
index 000000000000..8945e210ef69
--- /dev/null
+++ b/security/loadpol/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config SECURITY_LOADPOL
+	bool "LOADPOL support"
+	depends on SECURITY && MODULES
+	help
+	  Loadpol allows restricting the kernel modules that can be loaded
+	  dynamically according to a user-defined policy.
+
+	  If you are unsure how to answer this question, answer N. Otherwise,
+	  enable this and append "loadpol," to the CONFIG_LSM variable to
+	  enable Loadpol.
diff --git a/security/loadpol/Makefile b/security/loadpol/Makefile
new file mode 100644
index 000000000000..a794c8cfbfee
--- /dev/null
+++ b/security/loadpol/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SECURITY_LOADPOL) := loadpol.o
diff --git a/security/loadpol/loadpol.c b/security/loadpol/loadpol.c
new file mode 100644
index 000000000000..3fc29263e2f8
--- /dev/null
+++ b/security/loadpol/loadpol.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "linux/array_size.h"
+#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>
+
+#include "loadpol.h"
+
+static int __init loadpol_init(void);
+
+static const struct lsm_id loadpol_lsmid = {
+	.name = LOADPOL_NAME,
+	.id = LSM_ID_LOADPOL,
+};
+
+static struct security_hook_list loadpol_hooks[] __ro_after_init = {
+};
+
+DEFINE_LSM(LOADPOL_NAME) = {
+	.name = LOADPOL_NAME,
+	.init = loadpol_init,
+};
+
+static int __init loadpol_init(void)
+{
+	security_add_hooks(loadpol_hooks, ARRAY_SIZE(loadpol_hooks), &loadpol_lsmid);
+	pr_info("Loadpol started.\n");
+	return 0;
+}
diff --git a/security/loadpol/loadpol.h b/security/loadpol/loadpol.h
new file mode 100644
index 000000000000..5e11474191f0
--- /dev/null
+++ b/security/loadpol/loadpol.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _SECURITY_LOADPOL_LOADPOL_H
+#define _SECURITY_LOADPOL_LOADPOL_H
+
+#define LOADPOL_NAME "loadpol"
+
+#endif /* _SECURITY_LOADPOL_LOADPOL_H */
-- 
2.49.0