5 files changed, 150 insertions, 1 deletions
diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
index 5bd1cc1b4a54..4bb3a775a996 100644
--- a/security/integrity/Kconfig
+++ b/security/integrity/Kconfig
@@ -17,5 +17,17 @@ config INTEGRITY_SIGNATURE
 	  This is useful for evm and module keyrings, when keys are
 	  usually only added from initramfs.
 
+config INTEGRITY_ASYMMETRIC_KEYS
+	boolean "Enable asymmetric keys support"
+	depends on INTEGRITY_SIGNATURE
+	default n
+        select ASYMMETRIC_KEY_TYPE
+        select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+        select PUBLIC_KEY_ALGO_RSA
+        select X509_CERTIFICATE_PARSER
+	help
+	  This option enables digital signature verification using
+	  asymmetric keys.
+
 source security/integrity/ima/Kconfig
 source security/integrity/evm/Kconfig
diff --git a/security/integrity/Makefile b/security/integrity/Makefile
index d43799cc14f6..ebb6409b3fcb 100644
--- a/security/integrity/Makefile
+++ b/security/integrity/Makefile
@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_INTEGRITY) += integrity.o
 obj-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o
+obj-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o
 
 integrity-y := iint.o
 
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 2dc167d7cde9..0b759e17a131 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -44,5 +44,14 @@ int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
 		}
 	}
 
-	return digsig_verify(keyring[id], sig, siglen, digest, digestlen);
+	switch (sig[0]) {
+	case 1:
+		return digsig_verify(keyring[id], sig, siglen,
+				     digest, digestlen);
+	case 2:
+		return asymmetric_verify(keyring[id], sig, siglen,
+					 digest, digestlen);
+	}
+
+	return -EOPNOTSUPP;
 }
diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c
new file mode 100644
index 000000000000..b4754667659d
--- /dev/null
+++ b/security/integrity/digsig_asymmetric.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2013 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/key-type.h>
+#include <crypto/public_key.h>
+#include <keys/asymmetric-type.h>
+
+#include "integrity.h"
+
+/*
+ * signature format v2 - for using with asymmetric keys
+ */
+struct signature_v2_hdr {
+	uint8_t version;	/* signature format version */
+	uint8_t	hash_algo;	/* Digest algorithm [enum pkey_hash_algo] */
+	uint32_t keyid;		/* IMA key identifier - not X509/PGP specific*/
+	uint16_t sig_size;	/* signature size */
+	uint8_t sig[0];		/* signature payload */
+} __packed;
+
+/*
+ * Request an asymmetric key.
+ */
+static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid)
+{
+	struct key *key;
+	char name[12];
+
+	sprintf(name, "id:%x", keyid);
+
+	pr_debug("key search: \"%s\"\n", name);
+
+	if (keyring) {
+		/* search in specific keyring */
+		key_ref_t kref;
+		kref = keyring_search(make_key_ref(keyring, 1),
+				      &key_type_asymmetric, name);
+		if (IS_ERR(kref))
+			key = ERR_CAST(kref);
+		else
+			key = key_ref_to_ptr(kref);
+	} else {
+		key = request_key(&key_type_asymmetric, name, NULL);
+	}
+
+	if (IS_ERR(key)) {
+		pr_warn("Request for unknown key '%s' err %ld\n",
+			name, PTR_ERR(key));
+		switch (PTR_ERR(key)) {
+			/* Hide some search errors */
+		case -EACCES:
+		case -ENOTDIR:
+		case -EAGAIN:
+			return ERR_PTR(-ENOKEY);
+		default:
+			return key;
+		}
+	}
+
+	pr_debug("%s() = 0 [%x]\n", __func__, key_serial(key));
+
+	return key;
+}
+
+int asymmetric_verify(struct key *keyring, const char *sig,
+		      int siglen, const char *data, int datalen)
+{
+	struct public_key_signature pks;
+	struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
+	struct key *key;
+	int ret = -ENOMEM;
+
+	if (siglen <= sizeof(*hdr))
+		return -EBADMSG;
+
+	siglen -= sizeof(*hdr);
+
+	if (siglen != __be16_to_cpu(hdr->sig_size))
+		return -EBADMSG;
+
+	if (hdr->hash_algo >= PKEY_HASH__LAST)
+		return -ENOPKG;
+
+	key = request_asymmetric_key(keyring, __be32_to_cpu(hdr->keyid));
+	if (IS_ERR(key))
+		return PTR_ERR(key);
+
+	memset(&pks, 0, sizeof(pks));
+
+	pks.pkey_hash_algo = hdr->hash_algo;
+	pks.digest = (u8 *)data;
+	pks.digest_size = datalen;
+	pks.nr_mpi = 1;
+	pks.rsa.s = mpi_read_raw_data(hdr->sig, siglen);
+
+	if (pks.rsa.s)
+		ret = verify_signature(key, &pks);
+
+	mpi_free(pks.rsa.s);
+	key_put(key);
+	pr_debug("%s() = %d\n", __func__, ret);
+	return ret;
+}
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 0ae08fc88585..84c37c4db914 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -14,6 +14,7 @@
 #include <linux/types.h>
 #include <linux/integrity.h>
 #include <crypto/sha.h>
+#include <linux/key.h>
 
 /* iint action cache flags */
 #define IMA_MEASURE		0x00000001
@@ -101,5 +102,16 @@ static inline int integrity_digsig_verify(const unsigned int id,
 
 #endif /* CONFIG_INTEGRITY_SIGNATURE */
 
+#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
+int asymmetric_verify(struct key *keyring, const char *sig,
+		      int siglen, const char *data, int datalen);
+#else
+static inline int asymmetric_verify(struct key *keyring, const char *sig,
+				    int siglen, const char *data, int datalen)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
 /* set during initialization */
 extern int iint_initialized;