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From:   Nayna Jain <nayna@linux.ibm.com>
To:     linux-integrity@vger.kernel.org
Cc:     Mimi Zohar <zohar@linux.ibm.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Eric Snowberg <eric.snowberg@oracle.com>,
        Paul Moore <paul@paul-moore.com>,
        linux-security-module@vger.kernel.org,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        linux-kernel@vger.kernel.org, Nayna Jain <nayna@linux.ibm.com>
Subject: [PATCH v3 6/6] integrity: PowerVM support for loading third party code signing keys
Date:   Sat, 12 Aug 2023 22:15:31 -0400
Message-Id: <20230813021531.1382815-7-nayna@linux.ibm.com>
In-Reply-To: <20230813021531.1382815-1-nayna@linux.ibm.com>
References: <20230813021531.1382815-1-nayna@linux.ibm.com>
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On secure boot enabled PowerVM LPAR, third party code signing keys are
needed during early boot to verify signed third party modules. These
third party keys are stored in moduledb object in the Platform
KeyStore(PKS).

Load third party code signing keys onto .secondary_trusted_keys keyring.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
 certs/system_keyring.c                        | 30 +++++++++++++++++++
 include/keys/system_keyring.h                 |  7 +++++
 security/integrity/integrity.h                |  1 +
 .../platform_certs/keyring_handler.c          |  8 +++++
 .../platform_certs/keyring_handler.h          |  5 ++++
 .../integrity/platform_certs/load_powerpc.c   | 18 ++++++++++-
 6 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index b348e0898d34..e458d414918d 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -396,3 +396,33 @@ void __init set_platform_trusted_keys(struct key *keyring)
 	platform_trusted_keys = keyring;
 }
 #endif
+
+/**
+ * add_to_secondary_keyring - Add to secondary keyring.
+ * @source: Source of key
+ * @data: The blob holding the key
+ * @len: The length of the data blob
+ *
+ * Add a key to the secondary keyring. The key must be vouched for by a key in the builtin,
+ * machine or secondary keyring itself.
+ */
+void __init add_to_secondary_keyring(const char *source, const void *data, size_t len)
+{
+	key_ref_t key;
+	key_perm_t perm;
+
+	perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW;
+
+	key = key_create_or_update(make_key_ref(secondary_trusted_keys, 1),
+				   "asymmetric",
+				   NULL, data, len, perm,
+				   KEY_ALLOC_NOT_IN_QUOTA);
+	if (IS_ERR(key)) {
+		pr_err("Problem loading X.509 certificate from %s to secondary keyring %ld\n",
+		       source, PTR_ERR(key));
+		return;
+	}
+
+	pr_notice("Loaded X.509 cert '%s'\n", key_ref_to_ptr(key)->description);
+	key_ref_put(key);
+}
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 7e2583208820..4188f75d1bac 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -50,9 +50,16 @@ int restrict_link_by_digsig_builtin_and_secondary(struct key *keyring,
 						  const struct key_type *type,
 						  const union key_payload *payload,
 						  struct key *restriction_key);
+void __init add_to_secondary_keyring(const char *source, const void *data,
+				     size_t len);
+
 #else
 #define restrict_link_by_builtin_and_secondary_trusted restrict_link_by_builtin_trusted
 #define restrict_link_by_digsig_builtin_and_secondary restrict_link_by_digsig_builtin
+void __init add_to_secondary_keyring(const char *source, const void *data,
+				     size_t len)
+{
+}
 #endif
 
 #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index d7553c93f5c0..efaa2eb789ad 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -228,6 +228,7 @@ static inline int __init integrity_load_cert(const unsigned int id,
 {
 	return 0;
 }
+
 #endif /* CONFIG_INTEGRITY_SIGNATURE */
 
 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
index 586027b9a3f5..13ea17207902 100644
--- a/security/integrity/platform_certs/keyring_handler.c
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -78,6 +78,14 @@ __init efi_element_handler_t get_handler_for_ca_keys(const efi_guid_t *sig_type)
 	return NULL;
 }
 
+__init efi_element_handler_t get_handler_for_code_signing_keys(const efi_guid_t *sig_type)
+{
+	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+		return add_to_secondary_keyring;
+
+	return NULL;
+}
+
 /*
  * Return the appropriate handler for particular signature list types found in
  * the UEFI dbx and MokListXRT tables.
diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h
index 6f15bb4cc8dc..f92895cc50f6 100644
--- a/security/integrity/platform_certs/keyring_handler.h
+++ b/security/integrity/platform_certs/keyring_handler.h
@@ -34,6 +34,11 @@ efi_element_handler_t get_handler_for_mok(const efi_guid_t *sig_type);
  */
 efi_element_handler_t get_handler_for_ca_keys(const efi_guid_t *sig_type);
 
+/*
+ * Return the handler for particular signature list types for code signing keys.
+ */
+efi_element_handler_t get_handler_for_code_signing_keys(const efi_guid_t *sig_type);
+
 /*
  * Return the handler for particular signature list types found in the dbx.
  */
diff --git a/security/integrity/platform_certs/load_powerpc.c b/security/integrity/platform_certs/load_powerpc.c
index 6263ce3b3f1e..32c4e5fbf0fb 100644
--- a/security/integrity/platform_certs/load_powerpc.c
+++ b/security/integrity/platform_certs/load_powerpc.c
@@ -59,7 +59,7 @@ static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)
 static int __init load_powerpc_certs(void)
 {
 	void *db = NULL, *dbx = NULL, *data = NULL;
-	void *trustedca = NULL;
+	void *trustedca = NULL, *moduledb = NULL;
 	u64 dsize = 0;
 	u64 offset = 0;
 	int rc = 0;
@@ -137,6 +137,22 @@ static int __init load_powerpc_certs(void)
 		kfree(data);
 	}
 
+	data = get_cert_list("moduledb", 9,  &dsize);
+	if (!data) {
+		pr_info("Couldn't get moduledb list from firmware\n");
+	} else if (IS_ERR(data)) {
+		rc = PTR_ERR(data);
+		pr_err("Error reading moduledb from firmware: %d\n", rc);
+	} else {
+		extract_esl(moduledb, data, dsize, offset);
+
+		rc = parse_efi_signature_list("powerpc:moduledb", moduledb, dsize,
+					      get_handler_for_code_signing_keys);
+		if (rc)
+			pr_err("Couldn't parse moduledb signatures: %d\n", rc);
+		kfree(data);
+	}
+
 	return rc;
 }
 late_initcall(load_powerpc_certs);
-- 
2.31.1