[PATCH v2.1 6/7] integrity: digital signature verification using multiple keyrings

@@ -3,5 +3,19 @@ config INTEGRITY
 	def_bool y
 	depends on IMA || EVM
 
+config INTEGRITY_DIGSIG
+	boolean "Digital signature verification using multiple keyrings"
+	depends on INTEGRITY
+	default n
+	select DIGSIG
+	help
+	  This option enables digital signature verification support
+	  using multiple keyrings. It defines separate keyrings for each
+	  of the different use cases - evm, ima, and modules.
+	  Different keyrings improves search performance, but also allow
+	  to "lock" certain keyring to prevent adding new keys.
+	  This is useful for evm and module keyrings, when keys are
+	  usually only added from initramfs.
+
 source security/integrity/ima/Kconfig
 source security/integrity/evm/Kconfig

@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_INTEGRITY) += integrity.o
+obj-$(CONFIG_INTEGRITY_DIGSIG) += digsig.o
 
 integrity-y := iint.o
 

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2011 Intel Corporation
+ *
+ * Author:
+ * Dmitry Kasatkin <dmitry.kasatkin@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/err.h>
+#include <linux/rbtree.h>
+#include <linux/key-type.h>
+#include <linux/digsig.h>
+
+#include "integrity.h"
+
+static struct key *keyring[INTEGRITY_KEYRING_MAX];
+
+static const char *keyring_name[INTEGRITY_KEYRING_MAX] = {
+	"_evm",
+	"_module",
+	"_ima",
+};
+
+int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
+					const char *digest, int digestlen)
+{
+	if (id >= INTEGRITY_KEYRING_MAX)
+		return -EINVAL;
+
+	if (!keyring[id]) {
+		keyring[id] =
+			request_key(&key_type_keyring, keyring_name[id], NULL);
+		if (IS_ERR(keyring[id])) {
+			pr_err("no %s keyring: %ld\n", keyring_name[id],
+							PTR_ERR(keyring[id]));
+			keyring[id] = NULL;
+			return PTR_ERR(keyring[id]);
+		}
+	}
+
+	return digsig_verify(keyring[id], sig, siglen, digest, digestlen);
+}

@@ -51,5 +51,25 @@ struct integrity_iint_cache {
 struct integrity_iint_cache *integrity_iint_insert(struct inode *inode);
 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
 
+#define INTEGRITY_KEYRING_EVM		0
+#define INTEGRITY_KEYRING_MODULE	1
+#define INTEGRITY_KEYRING_IMA		2
+#define INTEGRITY_KEYRING_MAX		3
+
+#ifdef CONFIG_INTEGRITY_DIGSIG
+
+int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
+					const char *digest, int digestlen);
+
+#else
+
+static inline int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
+					const char *digest, int digestlen)
+{
+	return -EOPNOTSUPP;
+}
+
+#endif /* CONFIG_INTEGRITY_DIGSIG */
+
 /* set during initialization */
 extern int iint_initialized;