Resguardo inicial

linux-7.2.3/security/integrity/platform_certs/efi_parser.c

@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* EFI signature/key/certificate list parser
+ *
+ * Copyright (C) 2012, 2016 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) "EFI: "fmt
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/err.h>
+#include <linux/efi.h>
+
+/**
+ * parse_efi_signature_list - Parse an EFI signature list for certificates
+ * @source: The source of the key
+ * @data: The data blob to parse
+ * @size: The size of the data blob
+ * @get_handler_for_guid: Get the handler func for the sig type (or NULL)
+ *
+ * Parse an EFI signature list looking for elements of interest.  A list is
+ * made up of a series of sublists, where all the elements in a sublist are of
+ * the same type, but sublists can be of different types.
+ *
+ * For each sublist encountered, the @get_handler_for_guid function is called
+ * with the type specifier GUID and returns either a pointer to a function to
+ * handle elements of that type or NULL if the type is not of interest.
+ *
+ * If the sublist is of interest, each element is passed to the handler
+ * function in turn.
+ *
+ * Error EBADMSG is returned if the list doesn't parse correctly and 0 is
+ * returned if the list was parsed correctly.  No error can be returned from
+ * the @get_handler_for_guid function or the element handler function it
+ * returns.
+ */
+int __init parse_efi_signature_list(
+	const char *source,
+	const void *data, size_t size,
+	efi_element_handler_t (*get_handler_for_guid)(const efi_guid_t *))
+{
+	efi_element_handler_t handler;
+	unsigned int offs = 0;
+
+	pr_devel("-->%s(,%zu)\n", __func__, size);
+
+	while (size > 0) {
+		const efi_signature_data_t *elem;
+		efi_signature_list_t list;
+		size_t lsize, esize, hsize, elsize;
+
+		if (size < sizeof(list))
+			return -EBADMSG;
+
+		memcpy(&list, data, sizeof(list));
+		pr_devel("LIST[%04x] guid=%pUl ls=%x hs=%x ss=%x\n",
+			 offs,
+			 &list.signature_type, list.signature_list_size,
+			 list.signature_header_size, list.signature_size);
+
+		lsize = list.signature_list_size;
+		hsize = list.signature_header_size;
+		esize = list.signature_size;
+		elsize = lsize - sizeof(list) - hsize;
+
+		if (lsize > size) {
+			pr_devel("<--%s() = -EBADMSG [overrun @%x]\n",
+				 __func__, offs);
+			return -EBADMSG;
+		}
+
+		if (lsize < sizeof(list) ||
+		    lsize - sizeof(list) < hsize ||
+		    esize < sizeof(*elem) ||
+		    elsize < esize ||
+		    elsize % esize != 0) {
+			pr_devel("- bad size combo @%x\n", offs);
+			return -EBADMSG;
+		}
+
+		handler = get_handler_for_guid(&list.signature_type);
+		if (!handler) {
+			data += lsize;
+			size -= lsize;
+			offs += lsize;
+			continue;
+		}
+
+		data += sizeof(list) + hsize;
+		size -= sizeof(list) + hsize;
+		offs += sizeof(list) + hsize;
+
+		for (; elsize > 0; elsize -= esize) {
+			elem = data;
+
+			pr_devel("ELEM[%04x]\n", offs);
+			handler(source,
+				&elem->signature_data,
+				esize - sizeof(*elem));
+
+			data += esize;
+			size -= esize;
+			offs += esize;
+		}
+	}
+
+	return 0;
+}

linux-7.2.3/security/integrity/platform_certs/keyring_handler.c

@@ -0,0 +1,102 @@
+// 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"
+#include "keyring_handler.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 an X509 TBS hash.
+ */
+static __init void uefi_blacklist_x509_tbs(const char *source,
+					   const void *data, size_t len)
+{
+	mark_hash_blacklisted(data, len, BLACKLIST_HASH_X509_TBS);
+}
+
+/*
+ * Blacklist the hash of an executable.
+ */
+static __init void uefi_blacklist_binary(const char *source,
+					 const void *data, size_t len)
+{
+	mark_hash_blacklisted(data, len, BLACKLIST_HASH_BINARY);
+}
+
+/*
+ * Add an X509 cert to the revocation list.
+ */
+static __init void uefi_revocation_list_x509(const char *source,
+					     const void *data, size_t len)
+{
+	add_key_to_revocation_list(data, len);
+}
+
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the UEFI db 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 NULL;
+}
+
+/*
+ * 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) &&
+		    imputed_trust_enabled())
+			return add_to_machine_keyring;
+		else
+			return add_to_platform_keyring;
+	}
+	return NULL;
+}
+
+__init efi_element_handler_t get_handler_for_ca_keys(const efi_guid_t *sig_type)
+{
+	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+		return add_to_machine_keyring;
+
+	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.
+ */
+__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;
+	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+		return uefi_revocation_list_x509;
+	return NULL;
+}

linux-7.2.3/security/integrity/platform_certs/keyring_handler.h

@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef PLATFORM_CERTS_INTERNAL_H
+#define PLATFORM_CERTS_INTERNAL_H
+
+#include <linux/efi.h>
+
+void blacklist_hash(const char *source, const void *data,
+		    size_t len, const char *type,
+		    size_t type_len);
+
+/*
+ * Blacklist an X509 TBS hash.
+ */
+void blacklist_x509_tbs(const char *source, const void *data, size_t len);
+
+/*
+ * Blacklist the hash of an executable.
+ */
+void blacklist_binary(const char *source, const void *data, size_t len);
+
+/*
+ * Return the handler for particular signature list types found in the db.
+ */
+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 for CA keys.
+ */
+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.
+ */
+efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type);
+
+#endif
+
+#ifndef UEFI_QUIRK_SKIP_CERT
+#define UEFI_QUIRK_SKIP_CERT(vendor, product) \
+		 .matches = { \
+			DMI_MATCH(DMI_BOARD_VENDOR, vendor), \
+			DMI_MATCH(DMI_PRODUCT_NAME, product), \
+		},
+#endif

linux-7.2.3/security/integrity/platform_certs/load_ipl_s390.c

@@ -0,0 +1,36 @@
+// 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 <asm/boot_data.h>
+#include "../integrity.h"
+
+/*
+ * Load the certs contained in the IPL report created by the machine loader
+ * into the platform trusted keyring.
+ */
+static int __init load_ipl_certs(void)
+{
+	void *ptr, *end;
+	unsigned int len;
+
+	if (!ipl_cert_list_addr)
+		return 0;
+	/* Copy the certificates to the platform keyring */
+	ptr = __va(ipl_cert_list_addr);
+	end = ptr + ipl_cert_list_size;
+	while ((void *) ptr < end) {
+		len = *(unsigned int *) ptr;
+		ptr += sizeof(unsigned int);
+		add_to_platform_keyring("IPL:db", ptr, len);
+		ptr += len;
+	}
+	return 0;
+}
+late_initcall(load_ipl_certs);

linux-7.2.3/security/integrity/platform_certs/load_powerpc.c

@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ *
+ *      - loads keys and hashes stored and controlled by the firmware.
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <asm/secure_boot.h>
+#include <asm/secvar.h>
+#include "keyring_handler.h"
+#include "../integrity.h"
+
+#define extract_esl(db, data, size, offset)	\
+	do { db = data + offset; size = size - offset; } while (0)
+
+/*
+ * Get a certificate list blob from the named secure variable.
+ *
+ * Returns:
+ *  - a pointer to a kmalloc'd buffer containing the cert list on success
+ *  - NULL if the key does not exist
+ *  - an ERR_PTR on error
+ */
+static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)
+{
+	int rc;
+	void *db;
+
+	rc = secvar_ops->get(key, keylen, NULL, size);
+	if (rc) {
+		if (rc == -ENOENT)
+			return NULL;
+		return ERR_PTR(rc);
+	}
+
+	db = kmalloc(*size, GFP_KERNEL);
+	if (!db)
+		return ERR_PTR(-ENOMEM);
+
+	rc = secvar_ops->get(key, keylen, db, size);
+	if (rc) {
+		kfree(db);
+		return ERR_PTR(rc);
+	}
+
+	return db;
+}
+
+/*
+ * Load the certs contained in the keys databases into the platform trusted
+ * keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist
+ * keyring.
+ */
+static int __init load_powerpc_certs(void)
+{
+	void *db = NULL, *dbx = NULL, *data = NULL;
+	void *trustedca;
+	void *moduledb;
+	u64 dsize = 0;
+	u64 offset = 0;
+	int rc = 0;
+	ssize_t len;
+	char buf[32];
+
+	if (!secvar_ops)
+		return -ENODEV;
+
+	len = secvar_ops->format(buf, sizeof(buf));
+	if (len <= 0)
+		return -ENODEV;
+
+	// Check for known secure boot implementations from OPAL or PLPKS
+	if (strcmp("ibm,edk2-compat-v1", buf) && strcmp("ibm,plpks-sb-v1", buf) &&
+	    strcmp("ibm,plpks-sb-v0", buf)) {
+		pr_err("Unsupported secvar implementation \"%s\", not loading certs\n", buf);
+		return -ENODEV;
+	}
+
+	if (strcmp("ibm,plpks-sb-v1", buf) == 0 || strcmp("ibm,plpks-sb-v0", buf) == 0)
+		/* PLPKS authenticated variables ESL data is prefixed with 8 bytes of timestamp */
+		offset = 8;
+
+	/*
+	 * Get db, and dbx. They might not exist, so it isn't an error if we
+	 * can't get them.
+	 */
+	data = get_cert_list("db", 3, &dsize);
+	if (!data) {
+		pr_info("Couldn't get db list from firmware\n");
+	} else if (IS_ERR(data)) {
+		rc = PTR_ERR(data);
+		pr_err("Error reading db from firmware: %d\n", rc);
+		return rc;
+	} else {
+		extract_esl(db, data, dsize, offset);
+
+		rc = parse_efi_signature_list("powerpc:db", db, dsize,
+					      get_handler_for_db);
+		if (rc)
+			pr_err("Couldn't parse db signatures: %d\n", rc);
+		kfree(data);
+	}
+
+	data = get_cert_list("dbx", 4,  &dsize);
+	if (!data) {
+		pr_info("Couldn't get dbx list from firmware\n");
+	} else if (IS_ERR(data)) {
+		rc = PTR_ERR(data);
+		pr_err("Error reading dbx from firmware: %d\n", rc);
+		return rc;
+	} else {
+		extract_esl(dbx, data, dsize, offset);
+
+		rc = parse_efi_signature_list("powerpc:dbx", dbx, dsize,
+					      get_handler_for_dbx);
+		if (rc)
+			pr_err("Couldn't parse dbx signatures: %d\n", rc);
+		kfree(data);
+	}
+
+	data = get_cert_list("trustedcadb", 12,  &dsize);
+	if (!data) {
+		pr_info("Couldn't get trustedcadb list from firmware\n");
+	} else if (IS_ERR(data)) {
+		rc = PTR_ERR(data);
+		pr_err("Error reading trustedcadb from firmware: %d\n", rc);
+	} else {
+		extract_esl(trustedca, data, dsize, offset);
+
+		rc = parse_efi_signature_list("powerpc:trustedca", trustedca, dsize,
+					      get_handler_for_ca_keys);
+		if (rc)
+			pr_err("Couldn't parse trustedcadb signatures: %d\n", rc);
+		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);

linux-7.2.3/security/integrity/platform_certs/load_uefi.c

@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/dmi.h>
+#include <linux/err.h>
+#include <linux/efi.h>
+#include <linux/slab.h>
+#include <linux/ima.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include "../integrity.h"
+#include "keyring_handler.h"
+
+/*
+ * On T2 Macs reading the db and dbx efi variables to load UEFI Secure Boot
+ * certificates causes occurrence of a page fault in Apple's firmware and
+ * a crash disabling EFI runtime services. The following quirk skips reading
+ * these variables.
+ */
+static const struct dmi_system_id uefi_skip_cert[] = {
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,1") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,2") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,3") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,4") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,1") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,2") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,3") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,4") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,1") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,2") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir9,1") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "Macmini8,1") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacPro7,1") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,1") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,2") },
+	{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMacPro1,1") },
+	{ }
+};
+
+/*
+ * Look to see if a UEFI variable called MokIgnoreDB exists and return true if
+ * it does.
+ *
+ * This UEFI variable is set by the shim if a user tells the shim to not use
+ * the certs/hashes in the UEFI db variable for verification purposes.  If it
+ * is set, we should ignore the db variable also and the true return indicates
+ * this.
+ */
+static __init bool uefi_check_ignore_db(void)
+{
+	efi_status_t status;
+	unsigned int db = 0;
+	unsigned long size = sizeof(db);
+	efi_guid_t guid = EFI_SHIM_LOCK_GUID;
+
+	status = efi.get_variable(L"MokIgnoreDB", &guid, NULL, &size, &db);
+	return status == EFI_SUCCESS;
+}
+
+/*
+ * Get a certificate list blob from the named EFI variable.
+ */
+static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
+				  unsigned long *size, efi_status_t *status)
+{
+	unsigned long lsize = 4;
+	unsigned long tmpdb[4];
+	void *db;
+
+	*status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb);
+	if (*status == EFI_NOT_FOUND)
+		return NULL;
+
+	if (*status != EFI_BUFFER_TOO_SMALL) {
+		pr_err("Couldn't get size: 0x%lx\n", *status);
+		return NULL;
+	}
+
+	db = kmalloc(lsize, GFP_KERNEL);
+	if (!db)
+		return NULL;
+
+	*status = efi.get_variable(name, guid, NULL, &lsize, db);
+	if (*status != EFI_SUCCESS) {
+		kfree(db);
+		pr_err("Error reading db var: 0x%lx\n", *status);
+		return NULL;
+	}
+
+	*size = lsize;
+	return db;
+}
+
+/*
+ * load_moklist_certs() - Load MokList certs
+ *
+ * Load the certs contained in the UEFI MokListRT database into the
+ * platform trusted keyring.
+ *
+ * This routine checks the EFI MOK config table first. If and only if
+ * that fails, this routine uses the MokListRT ordinary UEFI variable.
+ *
+ * Return:	Status
+ */
+static int __init load_moklist_certs(void)
+{
+	struct efi_mokvar_table_entry *mokvar_entry;
+	efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
+	void *mok;
+	unsigned long moksize;
+	efi_status_t status;
+	int rc;
+
+	/* First try to load certs from the EFI MOKvar config table.
+	 * It's not an error if the MOKvar config table doesn't exist
+	 * or the MokListRT entry is not found in it.
+	 */
+	mokvar_entry = efi_mokvar_entry_find("MokListRT");
+	if (mokvar_entry) {
+		rc = parse_efi_signature_list("UEFI:MokListRT (MOKvar table)",
+					      mokvar_entry->data,
+					      mokvar_entry->data_size,
+					      get_handler_for_mok);
+		/* All done if that worked. */
+		if (!rc)
+			return rc;
+
+		pr_err("Couldn't parse MokListRT signatures from EFI MOKvar config table: %d\n",
+		       rc);
+	}
+
+	/* Get MokListRT. It might not exist, so it isn't an error
+	 * if we can't get it.
+	 */
+	mok = get_cert_list(L"MokListRT", &mok_var, &moksize, &status);
+	if (mok) {
+		rc = parse_efi_signature_list("UEFI:MokListRT",
+					      mok, moksize, get_handler_for_mok);
+		kfree(mok);
+		if (rc)
+			pr_err("Couldn't parse MokListRT signatures: %d\n", rc);
+		return rc;
+	}
+	if (status == EFI_NOT_FOUND)
+		pr_debug("MokListRT variable wasn't found\n");
+	else
+		pr_info("Couldn't get UEFI MokListRT\n");
+	return 0;
+}
+
+/*
+ * load_uefi_certs() - Load certs from UEFI sources
+ *
+ * Load the certs contained in the UEFI databases into the platform trusted
+ * keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist
+ * keyring.
+ */
+static int __init load_uefi_certs(void)
+{
+	efi_guid_t secure_var = EFI_IMAGE_SECURITY_DATABASE_GUID;
+	efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
+	void *db = NULL, *dbx = NULL, *mokx = NULL;
+	unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0;
+	efi_status_t status;
+	int rc = 0;
+	const struct dmi_system_id *dmi_id;
+
+	dmi_id = dmi_first_match(uefi_skip_cert);
+	if (dmi_id) {
+		pr_err("Reading UEFI Secure Boot Certs is not supported on T2 Macs.\n");
+		return false;
+	}
+
+	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
+		return false;
+
+	/* Get db and dbx.  They might not exist, so it isn't an error
+	 * if we can't get them.
+	 */
+	if (!uefi_check_ignore_db()) {
+		db = get_cert_list(L"db", &secure_var, &dbsize, &status);
+		if (!db) {
+			if (status == EFI_NOT_FOUND)
+				pr_debug("MODSIGN: db variable wasn't found\n");
+			else
+				pr_err("MODSIGN: Couldn't get UEFI db list\n");
+		} else {
+			rc = parse_efi_signature_list("UEFI:db",
+					db, dbsize, get_handler_for_db);
+			if (rc)
+				pr_err("Couldn't parse db signatures: %d\n",
+				       rc);
+			kfree(db);
+		}
+	}
+
+	dbx = get_cert_list(L"dbx", &secure_var, &dbxsize, &status);
+	if (!dbx) {
+		if (status == EFI_NOT_FOUND)
+			pr_debug("dbx variable wasn't found\n");
+		else
+			pr_info("Couldn't get UEFI dbx list\n");
+	} else {
+		rc = parse_efi_signature_list("UEFI:dbx",
+					      dbx, dbxsize,
+					      get_handler_for_dbx);
+		if (rc)
+			pr_err("Couldn't parse dbx signatures: %d\n", rc);
+		kfree(dbx);
+	}
+
+	/* the MOK/MOKx can not be trusted when secure boot is disabled */
+	if (!arch_get_secureboot())
+		return 0;
+
+	mokx = get_cert_list(L"MokListXRT", &mok_var, &mokxsize, &status);
+	if (!mokx) {
+		if (status == EFI_NOT_FOUND)
+			pr_debug("mokx variable wasn't found\n");
+		else
+			pr_info("Couldn't get mokx list\n");
+	} else {
+		rc = parse_efi_signature_list("UEFI:MokListXRT",
+					      mokx, mokxsize,
+					      get_handler_for_dbx);
+		if (rc)
+			pr_err("Couldn't parse mokx signatures %d\n", rc);
+		kfree(mokx);
+	}
+
+	/* Load the MokListRT certs */
+	rc = load_moklist_certs();
+
+	return rc;
+}
+late_initcall(load_uefi_certs);

linux-7.2.3/security/integrity/platform_certs/machine_keyring.c

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Machine keyring routines.
+ *
+ * Copyright (c) 2021, Oracle and/or its affiliates.
+ */
+
+#include <linux/efi.h>
+#include "../integrity.h"
+
+static __init int machine_keyring_init(void)
+{
+	int rc;
+
+	rc = integrity_init_keyring(INTEGRITY_KEYRING_MACHINE);
+	if (rc)
+		return rc;
+
+	pr_notice("Machine keyring initialized\n");
+	return 0;
+}
+device_initcall(machine_keyring_init);
+
+void __init add_to_machine_keyring(const char *source, const void *data, size_t len)
+{
+	key_perm_t perm;
+	int rc;
+
+	perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW;
+	rc = integrity_load_cert(INTEGRITY_KEYRING_MACHINE, source, data, len, perm);
+
+	/*
+	 * Some MOKList keys may not pass the machine keyring restrictions.
+	 * If the restriction check does not pass and the platform keyring
+	 * is configured, try to add it into that keyring instead.
+	 */
+	if (rc && efi_enabled(EFI_BOOT) &&
+	    IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING))
+		rc = integrity_load_cert(INTEGRITY_KEYRING_PLATFORM, source,
+					 data, len, perm);
+
+	if (rc)
+		pr_info("Error adding keys to machine keyring %s\n", source);
+}
+
+/*
+ * Try to load the MokListTrustedRT MOK variable to see if we should trust
+ * the MOK keys within the kernel. It is not an error if this variable
+ * does not exist.  If it does not exist, MOK keys should not be trusted
+ * within the machine keyring.
+ */
+static __init bool uefi_check_trust_mok_keys(void)
+{
+	struct efi_mokvar_table_entry *mokvar_entry;
+
+	mokvar_entry = efi_mokvar_entry_find("MokListTrustedRT");
+
+	if (mokvar_entry)
+		return true;
+
+	return false;
+}
+
+static bool __init trust_moklist(void)
+{
+	static bool initialized;
+	static bool trust_mok;
+
+	if (!initialized) {
+		initialized = true;
+		trust_mok = false;
+
+		if (uefi_check_trust_mok_keys())
+			trust_mok = true;
+	}
+
+	return trust_mok;
+}
+
+/*
+ * Provides platform specific check for trusting imputed keys before loading
+ * on .machine keyring. UEFI systems enable this trust based on a variable,
+ * and for other platforms, it is always enabled.
+ */
+bool __init imputed_trust_enabled(void)
+{
+	if (efi_enabled(EFI_BOOT))
+		return trust_moklist();
+
+	return true;
+}

linux-7.2.3/security/integrity/platform_certs/platform_keyring.c

@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Platform keyring for firmware/platform keys
+ *
+ * Copyright IBM Corporation, 2018
+ * Author(s): Nayna Jain <nayna@linux.ibm.com>
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include "../integrity.h"
+
+/**
+ * add_to_platform_keyring - Add to platform keyring without validation.
+ * @source: Source of key
+ * @data: The blob holding the key
+ * @len: The length of the data blob
+ *
+ * Add a key to the platform keyring without checking its trust chain.  This
+ * is available only during kernel initialisation.
+ */
+void __init add_to_platform_keyring(const char *source, const void *data,
+				    size_t len)
+{
+	key_perm_t perm;
+	int rc;
+
+	perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW;
+
+	rc = integrity_load_cert(INTEGRITY_KEYRING_PLATFORM, source, data, len,
+				 perm);
+	if (rc)
+		pr_info("Error adding keys to platform keyring %s\n", source);
+}
+
+/*
+ * Create the trusted keyrings.
+ */
+static __init int platform_keyring_init(void)
+{
+	int rc;
+
+	rc = integrity_init_keyring(INTEGRITY_KEYRING_PLATFORM);
+	if (rc)
+		return rc;
+
+	pr_notice("Platform Keyring initialized\n");
+	return 0;
+}
+
+/*
+ * Must be initialised before we try and load the keys into the keyring.
+ */
+device_initcall(platform_keyring_init);