Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 1341 insertions, 0 deletions

diff --git a/certs/.gitignore b/certs/.gitignore
new file mode 100644
index 0000000000..cec5465f31
--- /dev/null
+++ b/certs/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+/blacklist_hash_list
+/extract-cert
+/x509_certificate_list
+/x509_revocation_list
diff --git a/certs/Kconfig b/certs/Kconfig
new file mode 100644
index 0000000000..1f109b0708
--- /dev/null
+++ b/certs/Kconfig
@@ -0,0 +1,141 @@
+# SPDX-License-Identifier: GPL-2.0
+menu "Certificates for signature checking"
+
+config MODULE_SIG_KEY
+	string "File name or PKCS#11 URI of module signing key"
+	default "certs/signing_key.pem"
+	depends on MODULE_SIG || (IMA_APPRAISE_MODSIG && MODULES)
+	help
+         Provide the file name of a private key/certificate in PEM format,
+         or a PKCS#11 URI according to RFC7512. The file should contain, or
+         the URI should identify, both the certificate and its corresponding
+         private key.
+
+         If this option is unchanged from its default "certs/signing_key.pem",
+         then the kernel will automatically generate the private key and
+         certificate as described in Documentation/admin-guide/module-signing.rst
+
+choice
+	prompt "Type of module signing key to be generated"
+	depends on MODULE_SIG || (IMA_APPRAISE_MODSIG && MODULES)
+	help
+	 The type of module signing key type to generate. This option
+	 does not apply if a #PKCS11 URI is used.
+
+config MODULE_SIG_KEY_TYPE_RSA
+	bool "RSA"
+	help
+	 Use an RSA key for module signing.
+
+config MODULE_SIG_KEY_TYPE_ECDSA
+	bool "ECDSA"
+	select CRYPTO_ECDSA
+	help
+	 Use an elliptic curve key (NIST P384) for module signing. Consider
+	 using a strong hash like sha256 or sha384 for hashing modules.
+
+	 Note: Remove all ECDSA signing keys, e.g. certs/signing_key.pem,
+	 when falling back to building Linux 5.14 and older kernels.
+
+endchoice
+
+config SYSTEM_TRUSTED_KEYRING
+	bool "Provide system-wide ring of trusted keys"
+	depends on KEYS
+	depends on ASYMMETRIC_KEY_TYPE
+	depends on X509_CERTIFICATE_PARSER = y
+	help
+	  Provide a system keyring to which trusted keys can be added.  Keys in
+	  the keyring are considered to be trusted.  Keys may be added at will
+	  by the kernel from compiled-in data and from hardware key stores, but
+	  userspace may only add extra keys if those keys can be verified by
+	  keys already in the keyring.
+
+	  Keys in this keyring are used by module signature checking.
+
+config SYSTEM_TRUSTED_KEYS
+	string "Additional X.509 keys for default system keyring"
+	depends on SYSTEM_TRUSTED_KEYRING
+	help
+	  If set, this option should be the filename of a PEM-formatted file
+	  containing trusted X.509 certificates to be included in the default
+	  system keyring. Any certificate used for module signing is implicitly
+	  also trusted.
+
+	  NOTE: If you previously provided keys for the system keyring in the
+	  form of DER-encoded *.x509 files in the top-level build directory,
+	  those are no longer used. You will need to set this option instead.
+
+config SYSTEM_EXTRA_CERTIFICATE
+	bool "Reserve area for inserting a certificate without recompiling"
+	depends on SYSTEM_TRUSTED_KEYRING
+	help
+	  If set, space for an extra certificate will be reserved in the kernel
+	  image. This allows introducing a trusted certificate to the default
+	  system keyring without recompiling the kernel.
+
+config SYSTEM_EXTRA_CERTIFICATE_SIZE
+	int "Number of bytes to reserve for the extra certificate"
+	depends on SYSTEM_EXTRA_CERTIFICATE
+	default 4096
+	help
+	  This is the number of bytes reserved in the kernel image for a
+	  certificate to be inserted.
+
+config SECONDARY_TRUSTED_KEYRING
+	bool "Provide a keyring to which extra trustable keys may be added"
+	depends on SYSTEM_TRUSTED_KEYRING
+	help
+	  If set, provide a keyring to which extra keys may be added, provided
+	  those keys are not blacklisted and are vouched for by a key built
+	  into the kernel or already in the secondary trusted keyring.
+
+config SYSTEM_BLACKLIST_KEYRING
+	bool "Provide system-wide ring of blacklisted keys"
+	depends on KEYS
+	help
+	  Provide a system keyring to which blacklisted keys can be added.
+	  Keys in the keyring are considered entirely untrusted.  Keys in this
+	  keyring are used by the module signature checking to reject loading
+	  of modules signed with a blacklisted key.
+
+config SYSTEM_BLACKLIST_HASH_LIST
+	string "Hashes to be preloaded into the system blacklist keyring"
+	depends on SYSTEM_BLACKLIST_KEYRING
+	help
+	  If set, this option should be the filename of a list of hashes in the
+	  form "<hash>", "<hash>", ... .  This will be included into a C
+	  wrapper to incorporate the list into the kernel.  Each <hash> must be a
+	  string starting with a prefix ("tbs" or "bin"), then a colon (":"), and
+	  finally an even number of hexadecimal lowercase characters (up to 128).
+	  Certificate hashes can be generated with
+	  tools/certs/print-cert-tbs-hash.sh .
+
+config SYSTEM_REVOCATION_LIST
+	bool "Provide system-wide ring of revocation certificates"
+	depends on SYSTEM_BLACKLIST_KEYRING
+	depends on PKCS7_MESSAGE_PARSER=y
+	help
+	  If set, this allows revocation certificates to be stored in the
+	  blacklist keyring and implements a hook whereby a PKCS#7 message can
+	  be checked to see if it matches such a certificate.
+
+config SYSTEM_REVOCATION_KEYS
+	string "X.509 certificates to be preloaded into the system blacklist keyring"
+	depends on SYSTEM_REVOCATION_LIST
+	help
+	  If set, this option should be the filename of a PEM-formatted file
+	  containing X.509 certificates to be included in the default blacklist
+	  keyring.
+
+config SYSTEM_BLACKLIST_AUTH_UPDATE
+	bool "Allow root to add signed blacklist keys"
+	depends on SYSTEM_BLACKLIST_KEYRING
+	depends on SYSTEM_DATA_VERIFICATION
+	help
+	  If set, provide the ability to load new blacklist keys at run time if
+	  they are signed and vouched by a certificate from the builtin trusted
+	  keyring.  The PKCS#7 signature of the description is set in the key
+	  payload.  Blacklist keys cannot be removed.
+
+endmenu
diff --git a/certs/Makefile b/certs/Makefile
new file mode 100644
index 0000000000..799ad7b9e6
--- /dev/null
+++ b/certs/Makefile
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux kernel signature checking certificates.
+#
+
+obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
+obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist.o blacklist_hashes.o
+obj-$(CONFIG_SYSTEM_REVOCATION_LIST) += revocation_certificates.o
+
+$(obj)/blacklist_hashes.o: $(obj)/blacklist_hash_list
+CFLAGS_blacklist_hashes.o := -I $(obj)
+
+quiet_cmd_check_and_copy_blacklist_hash_list = GEN     $@
+      cmd_check_and_copy_blacklist_hash_list = \
+	$(if $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST), \
+	$(AWK) -f $(srctree)/$(src)/check-blacklist-hashes.awk $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST) >&2; \
+	{ cat $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST); echo $(comma) NULL; } > $@, \
+	echo NULL > $@)
+
+$(obj)/blacklist_hash_list: $(CONFIG_SYSTEM_BLACKLIST_HASH_LIST) FORCE
+	$(call if_changed,check_and_copy_blacklist_hash_list)
+
+targets += blacklist_hash_list
+
+quiet_cmd_extract_certs  = CERT    $@
+      cmd_extract_certs  = $(obj)/extract-cert "$(extract-cert-in)" $@
+extract-cert-in = $(filter-out $(obj)/extract-cert, $(real-prereqs))
+
+$(obj)/system_certificates.o: $(obj)/x509_certificate_list
+
+$(obj)/x509_certificate_list: $(CONFIG_SYSTEM_TRUSTED_KEYS) $(obj)/extract-cert FORCE
+	$(call if_changed,extract_certs)
+
+targets += x509_certificate_list
+
+# If module signing is requested, say by allyesconfig, but a key has not been
+# supplied, then one will need to be generated to make sure the build does not
+# fail and that the kernel may be used afterwards.
+#
+# We do it this way rather than having a boolean option for enabling an
+# external private key, because 'make randconfig' might enable such a
+# boolean option and we unfortunately can't make it depend on !RANDCONFIG.
+ifeq ($(CONFIG_MODULE_SIG_KEY),certs/signing_key.pem)
+
+keytype-$(CONFIG_MODULE_SIG_KEY_TYPE_ECDSA) := -newkey ec -pkeyopt ec_paramgen_curve:secp384r1
+
+quiet_cmd_gen_key = GENKEY  $@
+      cmd_gen_key = openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
+		-batch -x509 -config $< \
+		-outform PEM -out $@ -keyout $@ $(keytype-y) 2>&1
+
+$(obj)/signing_key.pem: $(obj)/x509.genkey FORCE
+	$(call if_changed,gen_key)
+
+targets += signing_key.pem
+
+quiet_cmd_copy_x509_config = COPY    $@
+      cmd_copy_x509_config = cat $(srctree)/$(src)/default_x509.genkey > $@
+
+# You can provide your own config file. If not present, copy the default one.
+$(obj)/x509.genkey:
+	$(call cmd,copy_x509_config)
+
+endif # CONFIG_MODULE_SIG_KEY
+
+$(obj)/system_certificates.o: $(obj)/signing_key.x509
+
+PKCS11_URI := $(filter pkcs11:%, $(CONFIG_MODULE_SIG_KEY))
+ifdef PKCS11_URI
+$(obj)/signing_key.x509: extract-cert-in := $(PKCS11_URI)
+endif
+
+$(obj)/signing_key.x509: $(filter-out $(PKCS11_URI),$(CONFIG_MODULE_SIG_KEY)) $(obj)/extract-cert FORCE
+	$(call if_changed,extract_certs)
+
+targets += signing_key.x509
+
+$(obj)/revocation_certificates.o: $(obj)/x509_revocation_list
+
+$(obj)/x509_revocation_list: $(CONFIG_SYSTEM_REVOCATION_KEYS) $(obj)/extract-cert FORCE
+	$(call if_changed,extract_certs)
+
+targets += x509_revocation_list
+
+hostprogs := extract-cert
+
+HOSTCFLAGS_extract-cert.o = $(shell $(HOSTPKG_CONFIG) --cflags libcrypto 2> /dev/null)
+HOSTLDLIBS_extract-cert = $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null || echo -lcrypto)
diff --git a/certs/blacklist.c b/certs/blacklist.c
new file mode 100644
index 0000000000..675dd7a8f0
--- /dev/null
+++ b/certs/blacklist.c
@@ -0,0 +1,375 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* System hash blacklist.
+ *
+ * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) "blacklist: "fmt
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/key.h>
+#include <linux/key-type.h>
+#include <linux/sched.h>
+#include <linux/ctype.h>
+#include <linux/err.h>
+#include <linux/seq_file.h>
+#include <linux/uidgid.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include "blacklist.h"
+
+/*
+ * According to crypto/asymmetric_keys/x509_cert_parser.c:x509_note_pkey_algo(),
+ * the size of the currently longest supported hash algorithm is 512 bits,
+ * which translates into 128 hex characters.
+ */
+#define MAX_HASH_LEN	128
+
+#define BLACKLIST_KEY_PERM (KEY_POS_SEARCH | KEY_POS_VIEW | \
+			    KEY_USR_SEARCH | KEY_USR_VIEW)
+
+static const char tbs_prefix[] = "tbs";
+static const char bin_prefix[] = "bin";
+
+static struct key *blacklist_keyring;
+
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+extern __initconst const u8 revocation_certificate_list[];
+extern __initconst const unsigned long revocation_certificate_list_size;
+#endif
+
+/*
+ * The description must be a type prefix, a colon and then an even number of
+ * hex digits.  The hash is kept in the description.
+ */
+static int blacklist_vet_description(const char *desc)
+{
+	int i, prefix_len, tbs_step = 0, bin_step = 0;
+
+	/* The following algorithm only works if prefix lengths match. */
+	BUILD_BUG_ON(sizeof(tbs_prefix) != sizeof(bin_prefix));
+	prefix_len = sizeof(tbs_prefix) - 1;
+	for (i = 0; *desc; desc++, i++) {
+		if (*desc == ':') {
+			if (tbs_step == prefix_len)
+				goto found_colon;
+			if (bin_step == prefix_len)
+				goto found_colon;
+			return -EINVAL;
+		}
+		if (i >= prefix_len)
+			return -EINVAL;
+		if (*desc == tbs_prefix[i])
+			tbs_step++;
+		if (*desc == bin_prefix[i])
+			bin_step++;
+	}
+	return -EINVAL;
+
+found_colon:
+	desc++;
+	for (i = 0; *desc && i < MAX_HASH_LEN; desc++, i++) {
+		if (!isxdigit(*desc) || isupper(*desc))
+			return -EINVAL;
+	}
+	if (*desc)
+		/* The hash is greater than MAX_HASH_LEN. */
+		return -ENOPKG;
+
+	/* Checks for an even number of hexadecimal characters. */
+	if (i == 0 || i & 1)
+		return -EINVAL;
+	return 0;
+}
+
+static int blacklist_key_instantiate(struct key *key,
+		struct key_preparsed_payload *prep)
+{
+#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE
+	int err;
+#endif
+
+	/* Sets safe default permissions for keys loaded by user space. */
+	key->perm = BLACKLIST_KEY_PERM;
+
+	/*
+	 * Skips the authentication step for builtin hashes, they are not
+	 * signed but still trusted.
+	 */
+	if (key->flags & (1 << KEY_FLAG_BUILTIN))
+		goto out;
+
+#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE
+	/*
+	 * Verifies the description's PKCS#7 signature against the builtin
+	 * trusted keyring.
+	 */
+	err = verify_pkcs7_signature(key->description,
+			strlen(key->description), prep->data, prep->datalen,
+			NULL, VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL);
+	if (err)
+		return err;
+#else
+	/*
+	 * It should not be possible to come here because the keyring doesn't
+	 * have KEY_USR_WRITE and the only other way to call this function is
+	 * for builtin hashes.
+	 */
+	WARN_ON_ONCE(1);
+	return -EPERM;
+#endif
+
+out:
+	return generic_key_instantiate(key, prep);
+}
+
+static int blacklist_key_update(struct key *key,
+		struct key_preparsed_payload *prep)
+{
+	return -EPERM;
+}
+
+static void blacklist_describe(const struct key *key, struct seq_file *m)
+{
+	seq_puts(m, key->description);
+}
+
+static struct key_type key_type_blacklist = {
+	.name			= "blacklist",
+	.vet_description	= blacklist_vet_description,
+	.instantiate		= blacklist_key_instantiate,
+	.update			= blacklist_key_update,
+	.describe		= blacklist_describe,
+};
+
+static char *get_raw_hash(const u8 *hash, size_t hash_len,
+		enum blacklist_hash_type hash_type)
+{
+	size_t type_len;
+	const char *type_prefix;
+	char *buffer, *p;
+
+	switch (hash_type) {
+	case BLACKLIST_HASH_X509_TBS:
+		type_len = sizeof(tbs_prefix) - 1;
+		type_prefix = tbs_prefix;
+		break;
+	case BLACKLIST_HASH_BINARY:
+		type_len = sizeof(bin_prefix) - 1;
+		type_prefix = bin_prefix;
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return ERR_PTR(-EINVAL);
+	}
+	buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL);
+	if (!buffer)
+		return ERR_PTR(-ENOMEM);
+	p = memcpy(buffer, type_prefix, type_len);
+	p += type_len;
+	*p++ = ':';
+	bin2hex(p, hash, hash_len);
+	p += hash_len * 2;
+	*p = '\0';
+	return buffer;
+}
+
+/**
+ * mark_raw_hash_blacklisted - Add a hash to the system blacklist
+ * @hash: The hash as a hex string with a type prefix (eg. "tbs:23aa429783")
+ */
+static int mark_raw_hash_blacklisted(const char *hash)
+{
+	key_ref_t key;
+
+	key = key_create(make_key_ref(blacklist_keyring, true),
+			 "blacklist",
+			 hash,
+			 NULL,
+			 0,
+			 BLACKLIST_KEY_PERM,
+			 KEY_ALLOC_NOT_IN_QUOTA |
+			 KEY_ALLOC_BUILT_IN);
+	if (IS_ERR(key)) {
+		if (PTR_ERR(key) == -EEXIST)
+			pr_warn("Duplicate blacklisted hash %s\n", hash);
+		else
+			pr_err("Problem blacklisting hash %s: %pe\n", hash, key);
+		return PTR_ERR(key);
+	}
+	return 0;
+}
+
+int mark_hash_blacklisted(const u8 *hash, size_t hash_len,
+		enum blacklist_hash_type hash_type)
+{
+	const char *buffer;
+	int err;
+
+	buffer = get_raw_hash(hash, hash_len, hash_type);
+	if (IS_ERR(buffer))
+		return PTR_ERR(buffer);
+	err = mark_raw_hash_blacklisted(buffer);
+	kfree(buffer);
+	return err;
+}
+
+/**
+ * is_hash_blacklisted - Determine if a hash is blacklisted
+ * @hash: The hash to be checked as a binary blob
+ * @hash_len: The length of the binary hash
+ * @hash_type: Type of hash
+ */
+int is_hash_blacklisted(const u8 *hash, size_t hash_len,
+		enum blacklist_hash_type hash_type)
+{
+	key_ref_t kref;
+	const char *buffer;
+	int ret = 0;
+
+	buffer = get_raw_hash(hash, hash_len, hash_type);
+	if (IS_ERR(buffer))
+		return PTR_ERR(buffer);
+	kref = keyring_search(make_key_ref(blacklist_keyring, true),
+			      &key_type_blacklist, buffer, false);
+	if (!IS_ERR(kref)) {
+		key_ref_put(kref);
+		ret = -EKEYREJECTED;
+	}
+
+	kfree(buffer);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(is_hash_blacklisted);
+
+int is_binary_blacklisted(const u8 *hash, size_t hash_len)
+{
+	if (is_hash_blacklisted(hash, hash_len, BLACKLIST_HASH_BINARY) ==
+			-EKEYREJECTED)
+		return -EPERM;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(is_binary_blacklisted);
+
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+/**
+ * add_key_to_revocation_list - Add a revocation certificate to the blacklist
+ * @data: The data blob containing the certificate
+ * @size: The size of data blob
+ */
+int add_key_to_revocation_list(const char *data, size_t size)
+{
+	key_ref_t key;
+
+	key = key_create_or_update(make_key_ref(blacklist_keyring, true),
+				   "asymmetric",
+				   NULL,
+				   data,
+				   size,
+				   KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH
+				   | KEY_USR_VIEW,
+				   KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN
+				   | KEY_ALLOC_BYPASS_RESTRICTION);
+
+	if (IS_ERR(key)) {
+		pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key));
+		return PTR_ERR(key);
+	}
+
+	return 0;
+}
+
+/**
+ * is_key_on_revocation_list - Determine if the key for a PKCS#7 message is revoked
+ * @pkcs7: The PKCS#7 message to check
+ */
+int is_key_on_revocation_list(struct pkcs7_message *pkcs7)
+{
+	int ret;
+
+	ret = pkcs7_validate_trust(pkcs7, blacklist_keyring);
+
+	if (ret == 0)
+		return -EKEYREJECTED;
+
+	return -ENOKEY;
+}
+#endif
+
+static int restrict_link_for_blacklist(struct key *dest_keyring,
+		const struct key_type *type, const union key_payload *payload,
+		struct key *restrict_key)
+{
+	if (type == &key_type_blacklist)
+		return 0;
+	return -EOPNOTSUPP;
+}
+
+/*
+ * Initialise the blacklist
+ *
+ * The blacklist_init() function is registered as an initcall via
+ * device_initcall().  As a result if the blacklist_init() function fails for
+ * any reason the kernel continues to execute.  While cleanly returning -ENODEV
+ * could be acceptable for some non-critical kernel parts, if the blacklist
+ * keyring fails to load it defeats the certificate/key based deny list for
+ * signed modules.  If a critical piece of security functionality that users
+ * expect to be present fails to initialize, panic()ing is likely the right
+ * thing to do.
+ */
+static int __init blacklist_init(void)
+{
+	const char *const *bl;
+	struct key_restriction *restriction;
+
+	if (register_key_type(&key_type_blacklist) < 0)
+		panic("Can't allocate system blacklist key type\n");
+
+	restriction = kzalloc(sizeof(*restriction), GFP_KERNEL);
+	if (!restriction)
+		panic("Can't allocate blacklist keyring restriction\n");
+	restriction->check = restrict_link_for_blacklist;
+
+	blacklist_keyring =
+		keyring_alloc(".blacklist",
+			      GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
+			      KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
+			      KEY_POS_WRITE |
+			      KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH
+#ifdef CONFIG_SYSTEM_BLACKLIST_AUTH_UPDATE
+			      | KEY_USR_WRITE
+#endif
+			      , KEY_ALLOC_NOT_IN_QUOTA |
+			      KEY_ALLOC_SET_KEEP,
+			      restriction, NULL);
+	if (IS_ERR(blacklist_keyring))
+		panic("Can't allocate system blacklist keyring\n");
+
+	for (bl = blacklist_hashes; *bl; bl++)
+		if (mark_raw_hash_blacklisted(*bl) < 0)
+			pr_err("- blacklisting failed\n");
+	return 0;
+}
+
+/*
+ * Must be initialised before we try and load the keys into the keyring.
+ */
+device_initcall(blacklist_init);
+
+#ifdef CONFIG_SYSTEM_REVOCATION_LIST
+/*
+ * Load the compiled-in list of revocation X.509 certificates.
+ */
+static __init int load_revocation_certificate_list(void)
+{
+	if (revocation_certificate_list_size)
+		pr_notice("Loading compiled-in revocation X.509 certificates\n");
+
+	return x509_load_certificate_list(revocation_certificate_list,
+					  revocation_certificate_list_size,
+					  blacklist_keyring);
+}
+late_initcall(load_revocation_certificate_list);
+#endif
diff --git a/certs/blacklist.h b/certs/blacklist.h
new file mode 100644
index 0000000000..51b320cf85
--- /dev/null
+++ b/certs/blacklist.h
@@ -0,0 +1,5 @@
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <crypto/pkcs7.h>
+
+extern const char __initconst *const blacklist_hashes[];
diff --git a/certs/blacklist_hashes.c b/certs/blacklist_hashes.c
new file mode 100644
index 0000000000..0c5476abeb
--- /dev/null
+++ b/certs/blacklist_hashes.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "blacklist.h"
+
+const char __initconst *const blacklist_hashes[] = {
+#include "blacklist_hash_list"
+};
diff --git a/certs/check-blacklist-hashes.awk b/certs/check-blacklist-hashes.awk
new file mode 100755
index 0000000000..107c1d3204
--- /dev/null
+++ b/certs/check-blacklist-hashes.awk
@@ -0,0 +1,37 @@
+#!/usr/bin/awk -f
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright © 2020, Microsoft Corporation. All rights reserved.
+#
+# Author: Mickaël Salaün <mic@linux.microsoft.com>
+#
+# Check that a CONFIG_SYSTEM_BLACKLIST_HASH_LIST file contains a valid array of
+# hash strings.  Such string must start with a prefix ("tbs" or "bin"), then a
+# colon (":"), and finally an even number of hexadecimal lowercase characters
+# (up to 128).
+
+BEGIN {
+	RS = ","
+}
+{
+	if (!match($0, "^[ \t\n\r]*\"([^\"]*)\"[ \t\n\r]*$", part1)) {
+		print "Not a string (item " NR "):", $0;
+		exit 1;
+	}
+	if (!match(part1[1], "^(tbs|bin):(.*)$", part2)) {
+		print "Unknown prefix (item " NR "):", part1[1];
+		exit 1;
+	}
+	if (!match(part2[2], "^([0-9a-f]+)$", part3)) {
+		print "Not a lowercase hexadecimal string (item " NR "):", part2[2];
+		exit 1;
+	}
+	if (length(part3[1]) > 128) {
+		print "Hash string too long (item " NR "):", part3[1];
+		exit 1;
+	}
+	if (length(part3[1]) % 2 == 1) {
+		print "Not an even number of hexadecimal characters (item " NR "):", part3[1];
+		exit 1;
+	}
+}
diff --git a/certs/default_x509.genkey b/certs/default_x509.genkey
new file mode 100644
index 0000000000..d4c6628cb8
--- /dev/null
+++ b/certs/default_x509.genkey
@@ -0,0 +1,17 @@
+[ req ]
+default_bits = 4096
+distinguished_name = req_distinguished_name
+prompt = no
+string_mask = utf8only
+x509_extensions = myexts
+
+[ req_distinguished_name ]
+#O = Unspecified company
+CN = Build time autogenerated kernel key
+#emailAddress = unspecified.user@unspecified.company
+
+[ myexts ]
+basicConstraints=critical,CA:FALSE
+keyUsage=digitalSignature
+subjectKeyIdentifier=hash
+authorityKeyIdentifier=keyid
diff --git a/certs/extract-cert.c b/certs/extract-cert.c
new file mode 100644
index 0000000000..70e9ec89d8
--- /dev/null
+++ b/certs/extract-cert.c
@@ -0,0 +1,172 @@
+/* Extract X.509 certificate in DER form from PKCS#11 or PEM.
+ *
+ * Copyright © 2014-2015 Red Hat, Inc. All Rights Reserved.
+ * Copyright © 2015      Intel Corporation.
+ *
+ * Authors: David Howells <dhowells@redhat.com>
+ *          David Woodhouse <dwmw2@infradead.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the licence, or (at your option) any later version.
+ */
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <err.h>
+#include <openssl/bio.h>
+#include <openssl/pem.h>
+#include <openssl/err.h>
+#include <openssl/engine.h>
+
+/*
+ * OpenSSL 3.0 deprecates the OpenSSL's ENGINE API.
+ *
+ * Remove this if/when that API is no longer used
+ */
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
+#define PKEY_ID_PKCS7 2
+
+static __attribute__((noreturn))
+void format(void)
+{
+	fprintf(stderr,
+		"Usage: extract-cert <source> <dest>\n");
+	exit(2);
+}
+
+static void display_openssl_errors(int l)
+{
+	const char *file;
+	char buf[120];
+	int e, line;
+
+	if (ERR_peek_error() == 0)
+		return;
+	fprintf(stderr, "At main.c:%d:\n", l);
+
+	while ((e = ERR_get_error_line(&file, &line))) {
+		ERR_error_string(e, buf);
+		fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
+	}
+}
+
+static void drain_openssl_errors(void)
+{
+	const char *file;
+	int line;
+
+	if (ERR_peek_error() == 0)
+		return;
+	while (ERR_get_error_line(&file, &line)) {}
+}
+
+#define ERR(cond, fmt, ...)				\
+	do {						\
+		bool __cond = (cond);			\
+		display_openssl_errors(__LINE__);	\
+		if (__cond) {				\
+			err(1, fmt, ## __VA_ARGS__);	\
+		}					\
+	} while(0)
+
+static const char *key_pass;
+static BIO *wb;
+static char *cert_dst;
+static bool verbose;
+
+static void write_cert(X509 *x509)
+{
+	char buf[200];
+
+	if (!wb) {
+		wb = BIO_new_file(cert_dst, "wb");
+		ERR(!wb, "%s", cert_dst);
+	}
+	X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf));
+	ERR(!i2d_X509_bio(wb, x509), "%s", cert_dst);
+	if (verbose)
+		fprintf(stderr, "Extracted cert: %s\n", buf);
+}
+
+int main(int argc, char **argv)
+{
+	char *cert_src;
+	char *verbose_env;
+
+	OpenSSL_add_all_algorithms();
+	ERR_load_crypto_strings();
+	ERR_clear_error();
+
+	verbose_env = getenv("KBUILD_VERBOSE");
+	if (verbose_env && strchr(verbose_env, '1'))
+		verbose = true;
+
+        key_pass = getenv("KBUILD_SIGN_PIN");
+
+	if (argc != 3)
+		format();
+
+	cert_src = argv[1];
+	cert_dst = argv[2];
+
+	if (!cert_src[0]) {
+		/* Invoked with no input; create empty file */
+		FILE *f = fopen(cert_dst, "wb");
+		ERR(!f, "%s", cert_dst);
+		fclose(f);
+		exit(0);
+	} else if (!strncmp(cert_src, "pkcs11:", 7)) {
+		ENGINE *e;
+		struct {
+			const char *cert_id;
+			X509 *cert;
+		} parms;
+
+		parms.cert_id = cert_src;
+		parms.cert = NULL;
+
+		ENGINE_load_builtin_engines();
+		drain_openssl_errors();
+		e = ENGINE_by_id("pkcs11");
+		ERR(!e, "Load PKCS#11 ENGINE");
+		if (ENGINE_init(e))
+			drain_openssl_errors();
+		else
+			ERR(1, "ENGINE_init");
+		if (key_pass)
+			ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
+		ENGINE_ctrl_cmd(e, "LOAD_CERT_CTRL", 0, &parms, NULL, 1);
+		ERR(!parms.cert, "Get X.509 from PKCS#11");
+		write_cert(parms.cert);
+	} else {
+		BIO *b;
+		X509 *x509;
+
+		b = BIO_new_file(cert_src, "rb");
+		ERR(!b, "%s", cert_src);
+
+		while (1) {
+			x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
+			if (wb && !x509) {
+				unsigned long err = ERR_peek_last_error();
+				if (ERR_GET_LIB(err) == ERR_LIB_PEM &&
+				    ERR_GET_REASON(err) == PEM_R_NO_START_LINE) {
+					ERR_clear_error();
+					break;
+				}
+			}
+			ERR(!x509, "%s", cert_src);
+			write_cert(x509);
+		}
+	}
+
+	BIO_free(wb);
+
+	return 0;
+}
diff --git a/certs/revocation_certificates.S b/certs/revocation_certificates.S
new file mode 100644
index 0000000000..f21aae8a8f
--- /dev/null
+++ b/certs/revocation_certificates.S
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/export.h>
+#include <linux/init.h>
+
+	__INITRODATA
+
+	.align 8
+	.globl revocation_certificate_list
+revocation_certificate_list:
+__revocation_list_start:
+	.incbin "certs/x509_revocation_list"
+__revocation_list_end:
+
+	.align 8
+	.globl revocation_certificate_list_size
+revocation_certificate_list_size:
+#ifdef CONFIG_64BIT
+	.quad __revocation_list_end - __revocation_list_start
+#else
+	.long __revocation_list_end - __revocation_list_start
+#endif
diff --git a/certs/system_certificates.S b/certs/system_certificates.S
new file mode 100644
index 0000000000..003e25d4a1
--- /dev/null
+++ b/certs/system_certificates.S
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/export.h>
+#include <linux/init.h>
+
+	__INITRODATA
+
+	.align 8
+	.globl system_certificate_list
+system_certificate_list:
+__cert_list_start:
+__module_cert_start:
+	.incbin "certs/signing_key.x509"
+__module_cert_end:
+	.incbin "certs/x509_certificate_list"
+__cert_list_end:
+
+#ifdef CONFIG_SYSTEM_EXTRA_CERTIFICATE
+	.globl system_extra_cert
+	.size system_extra_cert, CONFIG_SYSTEM_EXTRA_CERTIFICATE_SIZE
+system_extra_cert:
+	.fill CONFIG_SYSTEM_EXTRA_CERTIFICATE_SIZE, 1, 0
+
+	.align 4
+	.globl system_extra_cert_used
+system_extra_cert_used:
+	.int 0
+
+#endif /* CONFIG_SYSTEM_EXTRA_CERTIFICATE */
+
+	.align 8
+	.globl system_certificate_list_size
+system_certificate_list_size:
+#ifdef CONFIG_64BIT
+	.quad __cert_list_end - __cert_list_start
+#else
+	.long __cert_list_end - __cert_list_start
+#endif
+
+	.align 8
+	.globl module_cert_size
+module_cert_size:
+#ifdef CONFIG_64BIT
+	.quad __module_cert_end - __module_cert_start
+#else
+	.long __module_cert_end - __module_cert_start
+#endif
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
new file mode 100644
index 0000000000..9de610bf1f
--- /dev/null
+++ b/certs/system_keyring.c
@@ -0,0 +1,428 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* System trusted keyring for trusted public keys
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.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 <linux/uidgid.h>
+#include <linux/verification.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include <crypto/pkcs7.h>
+
+static struct key *builtin_trusted_keys;
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+static struct key *secondary_trusted_keys;
+#endif
+#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
+static struct key *machine_trusted_keys;
+#endif
+#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
+static struct key *platform_trusted_keys;
+#endif
+
+extern __initconst const u8 system_certificate_list[];
+extern __initconst const unsigned long system_certificate_list_size;
+extern __initconst const unsigned long module_cert_size;
+
+/**
+ * restrict_link_by_builtin_trusted - Restrict keyring addition by built-in CA
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @restriction_key: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in the built in system keyring.
+ */
+int restrict_link_by_builtin_trusted(struct key *dest_keyring,
+				     const struct key_type *type,
+				     const union key_payload *payload,
+				     struct key *restriction_key)
+{
+	return restrict_link_by_signature(dest_keyring, type, payload,
+					  builtin_trusted_keys);
+}
+
+/**
+ * restrict_link_by_digsig_builtin - Restrict digitalSignature key additions by the built-in keyring
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @restriction_key: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in the built in system keyring. The new key
+ * must have the digitalSignature usage field set.
+ */
+int restrict_link_by_digsig_builtin(struct key *dest_keyring,
+				    const struct key_type *type,
+				    const union key_payload *payload,
+				    struct key *restriction_key)
+{
+	return restrict_link_by_digsig(dest_keyring, type, payload,
+				       builtin_trusted_keys);
+}
+
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+/**
+ * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
+ *   addition by both built-in and secondary keyrings.
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @restrict_key: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in either the built-in or the secondary system
+ * keyrings.
+ */
+int restrict_link_by_builtin_and_secondary_trusted(
+	struct key *dest_keyring,
+	const struct key_type *type,
+	const union key_payload *payload,
+	struct key *restrict_key)
+{
+	/* If we have a secondary trusted keyring, then that contains a link
+	 * through to the builtin keyring and the search will follow that link.
+	 */
+	if (type == &key_type_keyring &&
+	    dest_keyring == secondary_trusted_keys &&
+	    payload == &builtin_trusted_keys->payload)
+		/* Allow the builtin keyring to be added to the secondary */
+		return 0;
+
+	return restrict_link_by_signature(dest_keyring, type, payload,
+					  secondary_trusted_keys);
+}
+
+/**
+ * restrict_link_by_digsig_builtin_and_secondary - Restrict by digitalSignature.
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @restrict_key: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in either the built-in or the secondary system
+ * keyrings. The new key must have the digitalSignature usage field set.
+ */
+int restrict_link_by_digsig_builtin_and_secondary(struct key *dest_keyring,
+						  const struct key_type *type,
+						  const union key_payload *payload,
+						  struct key *restrict_key)
+{
+	/* If we have a secondary trusted keyring, then that contains a link
+	 * through to the builtin keyring and the search will follow that link.
+	 */
+	if (type == &key_type_keyring &&
+	    dest_keyring == secondary_trusted_keys &&
+	    payload == &builtin_trusted_keys->payload)
+		/* Allow the builtin keyring to be added to the secondary */
+		return 0;
+
+	return restrict_link_by_digsig(dest_keyring, type, payload,
+				       secondary_trusted_keys);
+}
+
+/*
+ * Allocate a struct key_restriction for the "builtin and secondary trust"
+ * keyring. Only for use in system_trusted_keyring_init().
+ */
+static __init struct key_restriction *get_builtin_and_secondary_restriction(void)
+{
+	struct key_restriction *restriction;
+
+	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
+
+	if (!restriction)
+		panic("Can't allocate secondary trusted keyring restriction\n");
+
+	if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING))
+		restriction->check = restrict_link_by_builtin_secondary_and_machine;
+	else
+		restriction->check = restrict_link_by_builtin_and_secondary_trusted;
+
+	return restriction;
+}
+
+/**
+ * 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);
+}
+#endif
+#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
+void __init set_machine_trusted_keys(struct key *keyring)
+{
+	machine_trusted_keys = keyring;
+
+	if (key_link(secondary_trusted_keys, machine_trusted_keys) < 0)
+		panic("Can't link (machine) trusted keyrings\n");
+}
+
+/**
+ * restrict_link_by_builtin_secondary_and_machine - Restrict keyring addition.
+ * @dest_keyring: Keyring being linked to.
+ * @type: The type of key being added.
+ * @payload: The payload of the new key.
+ * @restrict_key: A ring of keys that can be used to vouch for the new cert.
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in either the built-in, the secondary, or
+ * the machine keyrings.
+ */
+int restrict_link_by_builtin_secondary_and_machine(
+	struct key *dest_keyring,
+	const struct key_type *type,
+	const union key_payload *payload,
+	struct key *restrict_key)
+{
+	if (machine_trusted_keys && type == &key_type_keyring &&
+	    dest_keyring == secondary_trusted_keys &&
+	    payload == &machine_trusted_keys->payload)
+		/* Allow the machine keyring to be added to the secondary */
+		return 0;
+
+	return restrict_link_by_builtin_and_secondary_trusted(dest_keyring, type,
+							      payload, restrict_key);
+}
+#endif
+
+/*
+ * Create the trusted keyrings
+ */
+static __init int system_trusted_keyring_init(void)
+{
+	pr_notice("Initialise system trusted keyrings\n");
+
+	builtin_trusted_keys =
+		keyring_alloc(".builtin_trusted_keys",
+			      GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
+			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+			      KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
+			      KEY_ALLOC_NOT_IN_QUOTA,
+			      NULL, NULL);
+	if (IS_ERR(builtin_trusted_keys))
+		panic("Can't allocate builtin trusted keyring\n");
+
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+	secondary_trusted_keys =
+		keyring_alloc(".secondary_trusted_keys",
+			      GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
+			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+			       KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
+			       KEY_USR_WRITE),
+			      KEY_ALLOC_NOT_IN_QUOTA,
+			      get_builtin_and_secondary_restriction(),
+			      NULL);
+	if (IS_ERR(secondary_trusted_keys))
+		panic("Can't allocate secondary trusted keyring\n");
+
+	if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
+		panic("Can't link trusted keyrings\n");
+#endif
+
+	return 0;
+}
+
+/*
+ * Must be initialised before we try and load the keys into the keyring.
+ */
+device_initcall(system_trusted_keyring_init);
+
+__init int load_module_cert(struct key *keyring)
+{
+	if (!IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG))
+		return 0;
+
+	pr_notice("Loading compiled-in module X.509 certificates\n");
+
+	return x509_load_certificate_list(system_certificate_list,
+					  module_cert_size, keyring);
+}
+
+/*
+ * Load the compiled-in list of X.509 certificates.
+ */
+static __init int load_system_certificate_list(void)
+{
+	const u8 *p;
+	unsigned long size;
+
+	pr_notice("Loading compiled-in X.509 certificates\n");
+
+#ifdef CONFIG_MODULE_SIG
+	p = system_certificate_list;
+	size = system_certificate_list_size;
+#else
+	p = system_certificate_list + module_cert_size;
+	size = system_certificate_list_size - module_cert_size;
+#endif
+
+	return x509_load_certificate_list(p, size, builtin_trusted_keys);
+}
+late_initcall(load_system_certificate_list);
+
+#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
+
+/**
+ * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data.
+ * @data: The data to be verified (NULL if expecting internal data).
+ * @len: Size of @data.
+ * @pkcs7: The PKCS#7 message that is the signature.
+ * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
+ *					(void *)1UL for all trusted keys).
+ * @usage: The use to which the key is being put.
+ * @view_content: Callback to gain access to content.
+ * @ctx: Context for callback.
+ */
+int verify_pkcs7_message_sig(const void *data, size_t len,
+			     struct pkcs7_message *pkcs7,
+			     struct key *trusted_keys,
+			     enum key_being_used_for usage,
+			     int (*view_content)(void *ctx,
+						 const void *data, size_t len,
+						 size_t asn1hdrlen),
+			     void *ctx)
+{
+	int ret;
+
+	/* The data should be detached - so we need to supply it. */
+	if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
+		pr_err("PKCS#7 signature with non-detached data\n");
+		ret = -EBADMSG;
+		goto error;
+	}
+
+	ret = pkcs7_verify(pkcs7, usage);
+	if (ret < 0)
+		goto error;
+
+	ret = is_key_on_revocation_list(pkcs7);
+	if (ret != -ENOKEY) {
+		pr_devel("PKCS#7 key is on revocation list\n");
+		goto error;
+	}
+
+	if (!trusted_keys) {
+		trusted_keys = builtin_trusted_keys;
+	} else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+		trusted_keys = secondary_trusted_keys;
+#else
+		trusted_keys = builtin_trusted_keys;
+#endif
+	} else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) {
+#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
+		trusted_keys = platform_trusted_keys;
+#else
+		trusted_keys = NULL;
+#endif
+		if (!trusted_keys) {
+			ret = -ENOKEY;
+			pr_devel("PKCS#7 platform keyring is not available\n");
+			goto error;
+		}
+	}
+	ret = pkcs7_validate_trust(pkcs7, trusted_keys);
+	if (ret < 0) {
+		if (ret == -ENOKEY)
+			pr_devel("PKCS#7 signature not signed with a trusted key\n");
+		goto error;
+	}
+
+	if (view_content) {
+		size_t asn1hdrlen;
+
+		ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
+		if (ret < 0) {
+			if (ret == -ENODATA)
+				pr_devel("PKCS#7 message does not contain data\n");
+			goto error;
+		}
+
+		ret = view_content(ctx, data, len, asn1hdrlen);
+	}
+
+error:
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+
+/**
+ * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
+ * @data: The data to be verified (NULL if expecting internal data).
+ * @len: Size of @data.
+ * @raw_pkcs7: The PKCS#7 message that is the signature.
+ * @pkcs7_len: The size of @raw_pkcs7.
+ * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
+ *					(void *)1UL for all trusted keys).
+ * @usage: The use to which the key is being put.
+ * @view_content: Callback to gain access to content.
+ * @ctx: Context for callback.
+ */
+int verify_pkcs7_signature(const void *data, size_t len,
+			   const void *raw_pkcs7, size_t pkcs7_len,
+			   struct key *trusted_keys,
+			   enum key_being_used_for usage,
+			   int (*view_content)(void *ctx,
+					       const void *data, size_t len,
+					       size_t asn1hdrlen),
+			   void *ctx)
+{
+	struct pkcs7_message *pkcs7;
+	int ret;
+
+	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
+	if (IS_ERR(pkcs7))
+		return PTR_ERR(pkcs7);
+
+	ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage,
+				       view_content, ctx);
+
+	pkcs7_free_message(pkcs7);
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
+
+#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
+
+#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
+void __init set_platform_trusted_keys(struct key *keyring)
+{
+	platform_trusted_keys = keyring;
+}
+#endif