1 files changed, 80 insertions, 0 deletions
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
new file mode 100644
index 000000000000..c5ba695c10e3
--- /dev/null
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/efi.h>
+#include <linux/slab.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include "../integrity.h"
+
+static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
+static efi_guid_t efi_cert_x509_sha256_guid __initdata =
+	EFI_CERT_X509_SHA256_GUID;
+static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID;
+
+/*
+ * Blacklist a hash.
+ */
+static __init void uefi_blacklist_hash(const char *source, const void *data,
+				       size_t len, const char *type,
+				       size_t type_len)
+{
+	char *hash, *p;
+
+	hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
+	if (!hash)
+		return;
+	p = memcpy(hash, type, type_len);
+	p += type_len;
+	bin2hex(p, data, len);
+	p += len * 2;
+	*p = 0;
+
+	mark_hash_blacklisted(hash);
+	kfree(hash);
+}
+
+/*
+ * Blacklist an X509 TBS hash.
+ */
+static __init void uefi_blacklist_x509_tbs(const char *source,
+					   const void *data, size_t len)
+{
+	uefi_blacklist_hash(source, data, len, "tbs:", 4);
+}
+
+/*
+ * Blacklist the hash of an executable.
+ */
+static __init void uefi_blacklist_binary(const char *source,
+					 const void *data, size_t len)
+{
+	uefi_blacklist_hash(source, data, len, "bin:", 4);
+}
+
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the UEFI db and MokListRT tables.
+ */
+__init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
+{
+	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+		return add_to_platform_keyring;
+	return 0;
+}
+
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the UEFI dbx and MokListXRT tables.
+ */
+__init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
+{
+	if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
+		return uefi_blacklist_x509_tbs;
+	if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
+		return uefi_blacklist_binary;
+	return 0;
+}