[PATCH v5 07/14] module: Make module authentication usable without MODULE_SIG

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

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

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 crypto/algapi.c          |  4 ++--
 include/linux/module.h   | 18 +++++++++---------
 kernel/module/Kconfig    |  5 ++++-
 kernel/module/Makefile   |  1 +
 kernel/module/auth.c     | 32 ++++++++++++++++++++++++++++++++
 kernel/module/internal.h |  2 +-
 kernel/module/main.c     |  8 ++++----
 kernel/module/signing.c  | 23 +----------------------
 8 files changed, 54 insertions(+), 39 deletions(-)

diff --git a/crypto/algapi.c b/crypto/algapi.c
index 37de377719ae..14252b780266 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -24,8 +24,8 @@ static LIST_HEAD(crypto_template_list);
 
 static inline void crypto_check_module_sig(struct module *mod)
 {
-	if (fips_enabled && mod && !module_sig_ok(mod))
-		panic("Module %s signature verification failed in FIPS mode\n",
+	if (fips_enabled && mod && !module_auth_ok(mod))
+		panic("Module %s authentication failed in FIPS mode\n",
 		      module_name(mod));
 }
 
diff --git a/include/linux/module.h b/include/linux/module.h
index 7566815fabbe..b4760777daad 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -437,9 +437,9 @@ struct module {
 	/* GPL-only exported symbols. */
 	bool using_gplonly_symbols;
 
-#ifdef CONFIG_MODULE_SIG
-	/* Signature was verified. */
-	bool sig_ok;
+#ifdef CONFIG_MODULE_AUTH
+	/* Module was authenticated. */
+	bool auth_ok;
 #endif
 
 	bool async_probe_requested;
@@ -918,16 +918,16 @@ static inline bool retpoline_module_ok(bool has_retpoline)
 }
 #endif
 
-#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_AUTH
 bool is_module_sig_enforced(void);
 
 void set_module_sig_enforced(void);
 
-static inline bool module_sig_ok(struct module *module)
+static inline bool module_auth_ok(struct module *module)
 {
-	return module->sig_ok;
+	return module->auth_ok;
 }
-#else	/* !CONFIG_MODULE_SIG */
+#else	/* !CONFIG_MODULE_AUTH */
 static inline bool is_module_sig_enforced(void)
 {
 	return false;
@@ -937,11 +937,11 @@ static inline void set_module_sig_enforced(void)
 {
 }
 
-static inline bool module_sig_ok(struct module *module)
+static inline bool module_auth_ok(struct module *module)
 {
 	return true;
 }
-#endif	/* CONFIG_MODULE_SIG */
+#endif	/* CONFIG_MODULE_AUTH */
 
 #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 f535181e0d98..84297da666ff 100644
--- a/kernel/module/Kconfig
+++ b/kernel/module/Kconfig
@@ -271,9 +271,12 @@ 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_AUTH
+	def_bool MODULE_SIG
+
 config MODULE_SIG_FORCE
 	bool "Require modules to be validly signed"
-	depends on MODULE_SIG
+	depends on MODULE_AUTH
 	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/Makefile b/kernel/module/Makefile
index d9e8759a7b05..c7200e293d04 100644
--- a/kernel/module/Makefile
+++ b/kernel/module/Makefile
@@ -14,6 +14,7 @@ obj-y += strict_rwx.o
 obj-y += kmod.o
 obj-$(CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS) += dups.o
 obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
+obj-$(CONFIG_MODULE_AUTH) += auth.o
 obj-$(CONFIG_MODULE_SIG) += signing.o
 obj-$(CONFIG_LIVEPATCH) += livepatch.o
 obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o
diff --git a/kernel/module/auth.c b/kernel/module/auth.c
new file mode 100644
index 000000000000..956ac63d9d33
--- /dev/null
+++ b/kernel/module/auth.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Module authentication checker
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.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;
+}
diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index 006ada7d4e6e..f8f425b167f1 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -68,7 +68,7 @@ struct load_info {
 	Elf_Shdr *sechdrs;
 	char *secstrings, *strtab;
 	unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
-	bool sig_ok;
+	bool auth_ok;
 #ifdef CONFIG_KALLSYMS
 	unsigned long mod_kallsyms_init_off;
 #endif
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 17a352198016..cd8a74df117e 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2601,10 +2601,10 @@ 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
-	mod->sig_ok = info->sig_ok;
-	if (!mod->sig_ok) {
-		pr_notice_once("%s: module verification failed: signature "
+#ifdef CONFIG_MODULE_AUTH
+	mod->auth_ok = info->auth_ok;
+	if (!mod->auth_ok) {
+		pr_notice_once("%s: module authentication failed: signature "
 			       "and/or required key missing - tainting "
 			       "kernel\n", mod->name);
 		add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index 69d4b1758540..07a786723221 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.
  */
@@ -84,7 +63,7 @@ int module_sig_check(struct load_info *info, int flags)
 		info->len -= markerlen;
 		err = mod_verify_sig(mod, info);
 		if (!err) {
-			info->sig_ok = true;
+			info->auth_ok = true;
 			return 0;
 		}
 	}

-- 
2.54.0