Thread (41 messages) 41 messages, 4 authors, 2021-11-19

[PATCH v7 08/17] integrity: add new keyring handler for mok keys

From: Eric Snowberg <eric.snowberg@oracle.com>
Date: 2021-11-16 00:19:54
Also in: keyrings, linux-crypto, linux-efi, linux-integrity, lkml
Subsystem: extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds

Currently both Secure Boot DB and Machine Owner Keys (MOK) go through
the same keyring handler (get_handler_for_db). With the addition of the
new machine keyring, the end-user may choose to trust MOK keys.

Introduce a new keyring handler specific for MOK keys.  If MOK keys are
trusted by the end-user, use the new keyring handler instead.

Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
---
v1: Initial version
v3: Only change the keyring handler if the secondary is enabled
v4: Removed trust_moklist check
v5: Rename to machine keyring
v7: Unmodified from v5
---
 .../integrity/platform_certs/keyring_handler.c  | 17 ++++++++++++++++-
 .../integrity/platform_certs/keyring_handler.h  |  5 +++++
 security/integrity/platform_certs/load_uefi.c   |  4 ++--
 3 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
index e9791be98fd9..4872850d081f 100644
--- a/security/integrity/platform_certs/keyring_handler.c
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -67,7 +67,7 @@ static __init void uefi_revocation_list_x509(const char *source,
 
 /*
  * Return the appropriate handler for particular signature list types found in
- * the UEFI db and MokListRT tables.
+ * the UEFI db tables.
  */
 __init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
 {
@@ -76,6 +76,21 @@ __init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
 	return 0;
 }
 
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the MokListRT tables.
+ */
+__init efi_element_handler_t get_handler_for_mok(const efi_guid_t *sig_type)
+{
+	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0) {
+		if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING))
+			return add_to_machine_keyring;
+		else
+			return add_to_platform_keyring;
+	}
+	return 0;
+}
+
 /*
  * 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 2462bfa08fe3..284558f30411 100644
--- a/security/integrity/platform_certs/keyring_handler.h
+++ b/security/integrity/platform_certs/keyring_handler.h
@@ -24,6 +24,11 @@ void blacklist_binary(const char *source, const void *data, size_t len);
  */
 efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type);
 
+/*
+ * Return the handler for particular signature list types found in the mok.
+ */
+efi_element_handler_t get_handler_for_mok(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_uefi.c b/security/integrity/platform_certs/load_uefi.c
index f290f78c3f30..c1bfd1cd7cc3 100644
--- a/security/integrity/platform_certs/load_uefi.c
+++ b/security/integrity/platform_certs/load_uefi.c
@@ -94,7 +94,7 @@ static int __init load_moklist_certs(void)
 		rc = parse_efi_signature_list("UEFI:MokListRT (MOKvar table)",
 					      mokvar_entry->data,
 					      mokvar_entry->data_size,
-					      get_handler_for_db);
+					      get_handler_for_mok);
 		/* All done if that worked. */
 		if (!rc)
 			return rc;
@@ -109,7 +109,7 @@ static int __init load_moklist_certs(void)
 	mok = get_cert_list(L"MokListRT", &mok_var, &moksize, &status);
 	if (mok) {
 		rc = parse_efi_signature_list("UEFI:MokListRT",
-					      mok, moksize, get_handler_for_db);
+					      mok, moksize, get_handler_for_mok);
 		kfree(mok);
 		if (rc)
 			pr_err("Couldn't parse MokListRT signatures: %d\n", rc);
-- 
2.18.4
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