[PATCH v2 2/6] module: Make module loading policy usable without MODULE_SIG

["Thomas Weißschuh" <linux@weissschuh.net>]

The loading policy functionality will also be used by the hash-based
module validation. Split it out from CONFIG_MODULE_SIG so it is usable
by both.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 include/linux/module.h  |  8 ++++----
 kernel/module/Kconfig   |  6 +++++-
 kernel/module/main.c    | 26 +++++++++++++++++++++++++-
 kernel/module/signing.c | 21 ---------------------
 4 files changed, 34 insertions(+), 27 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index b3a643435357986f3f9fe852260ca07f371cf86c..ccddab25d277da84d8c2866a9b4ded7c18691c0d 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -451,7 +451,7 @@ struct module {
 	const s32 *gpl_crcs;
 	bool using_gplonly_symbols;
 
-#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_POLICY
 	/* Signature was verified. */
 	bool sig_ok;
 #endif
@@ -928,14 +928,14 @@ static inline bool retpoline_module_ok(bool has_retpoline)
 }
 #endif
 
-#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_POLICY
 bool is_module_sig_enforced(void);
 
 static inline bool module_sig_ok(struct module *module)
 {
 	return module->sig_ok;
 }
-#else	/* !CONFIG_MODULE_SIG */
+#else	/* !CONFIG_MODULE_SIG_POLICY */
 static inline bool is_module_sig_enforced(void)
 {
 	return false;
@@ -945,7 +945,7 @@ static inline bool module_sig_ok(struct module *module)
 {
 	return true;
 }
-#endif	/* CONFIG_MODULE_SIG */
+#endif	/* CONFIG_MODULE_SIG_POLICY */
 
 #if defined(CONFIG_MODULES) && defined(CONFIG_KALLSYMS)
 int module_kallsyms_on_each_symbol(const char *modname,
diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
index 7b329057997ad2ec310133ca84617d9bfcdb7e9f..a80de8d22efdd0f13b3eb579a8ff1e69029d0694 100644
--- a/kernel/module/Kconfig
+++ b/kernel/module/Kconfig
@@ -210,9 +210,13 @@ config MODULE_SIG
 	  debuginfo strip done by some packagers (such as rpmbuild) and
 	  inclusion into an initramfs that wants the module size reduced.
 
+config MODULE_SIG_POLICY
+	def_bool y
+	depends on MODULE_SIG
+
 config MODULE_SIG_FORCE
 	bool "Require modules to be validly signed"
-	depends on MODULE_SIG
+	depends on MODULE_SIG_POLICY
 	help
 	  Reject unsigned modules or signed modules for which we don't have a
 	  key.  Without this, such modules will simply taint the kernel.
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 5399c182b3cbed2dbeea0291f717f30358d8e7fc..8aa593fee22a227a482466dceda4a6b657b956e0 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2367,7 +2367,7 @@ static void module_augment_kernel_taints(struct module *mod, struct load_info *i
 				mod->name);
 		add_taint_module(mod, TAINT_TEST, LOCKDEP_STILL_OK);
 	}
-#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_POLICY
 	mod->sig_ok = info->sig_ok;
 	if (!mod->sig_ok) {
 		pr_notice_once("%s: module verification failed: signature "
@@ -3779,3 +3779,27 @@ static int module_debugfs_init(void)
 }
 module_init(module_debugfs_init);
 #endif
+
+#ifdef CONFIG_MODULE_SIG_POLICY
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "module."
+
+static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
+module_param(sig_enforce, bool_enable_only, 0644);
+
+/*
+ * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
+ * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
+ */
+bool is_module_sig_enforced(void)
+{
+	return sig_enforce;
+}
+EXPORT_SYMBOL(is_module_sig_enforced);
+
+void set_module_sig_enforced(void)
+{
+	sig_enforce = true;
+}
+#endif
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index a2ff4242e623d5d4e87d2f3d139d8620fb937579..e51920605da14771601327ea596dad2e12400518 100644
--- a/kernel/module/signing.c
+++ b/kernel/module/signing.c
@@ -16,27 +16,6 @@
 #include <uapi/linux/module.h>
 #include "internal.h"
 
-#undef MODULE_PARAM_PREFIX
-#define MODULE_PARAM_PREFIX "module."
-
-static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
-module_param(sig_enforce, bool_enable_only, 0644);
-
-/*
- * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
- * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
- */
-bool is_module_sig_enforced(void)
-{
-	return sig_enforce;
-}
-EXPORT_SYMBOL(is_module_sig_enforced);
-
-void set_module_sig_enforced(void)
-{
-	sig_enforce = true;
-}
-
 /*
  * Verify the signature on a module.
  */

-- 
2.48.1