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Commit 22d01afb authored by David Howells's avatar David Howells
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PKCS#7: Provide a key type for testing PKCS#7



Provide a key type for testing the PKCS#7 parser.  It is given a non-detached
PKCS#7 message as payload:

	keyctl padd pkcs7_test a @s <stuff.pkcs7

The PKCS#7 wrapper is validated against the trusted certificates available and
then stripped off.  If successful, the key can be read, which will give the
data content of the PKCS#7 message.

A suitable message can be created by running make on the attached Makefile.
This will produce a file called stuff.pkcs7 for test loading.  The key3.x509
file should be put into the kernel source tree before it is built and
converted to DER form:

	openssl x509 -in .../pkcs7/key3.x509 -outform DER -out key3.x509

###############################################################################
#
# Create a pkcs7 message and sign it twice
#
#	openssl x509 -text -inform PEM -noout -in key2.x509
#
###############################################################################
stuff.pkcs7: stuff.txt key2.priv key2.x509 key4.priv key4.x509 certs
	$(RM) $@
	openssl smime -sign \
		-signer key2.x509 \
		-inkey key2.priv \
		-signer key4.x509 \
		-inkey key4.priv \
		-in stuff.txt \
		-certfile certs \
		-out $@ -binary -outform DER -nodetach
	openssl pkcs7 -inform DER -in stuff.pkcs7  -print_certs -noout
	openssl asn1parse -inform DER -in stuff.pkcs7  -i >out

stuff.txt:
	echo "The quick red fox jumped over the lazy brown dog" >stuff.txt

certs: key1.x509 key2.x509 key3.x509 key4.x509
	cat key{1,3}.x509 >$@

###############################################################################
#
# Generate a signed key
#
#	openssl x509 -text -inform PEM -noout -in key2.x509
#
###############################################################################
key2.x509: key2.x509_unsigned key1.priv key1.x509
	openssl x509 \
		-req -in key2.x509_unsigned \
		-out key2.x509 \
		-extfile key2.genkey -extensions myexts \
		-CA key1.x509 \
		-CAkey key1.priv \
		-CAcreateserial

key2.priv key2.x509_unsigned: key2.genkey
	openssl req -new -nodes -utf8 -sha1 -days 36500 \
		-batch -outform PEM \
		-config key2.genkey \
		-keyout key2.priv \
		-out key2.x509_unsigned

key2.genkey:
	@echo Generating X.509 key generation config
	@echo  >$@ "[ req ]"
	@echo >>$@ "default_bits = 4096"
	@echo >>$@ "distinguished_name = req_distinguished_name"
	@echo >>$@ "prompt = no"
	@echo >>$@ "string_mask = utf8only"
	@echo >>$@ "x509_extensions = myexts"
	@echo >>$@
	@echo >>$@ "[ req_distinguished_name ]"
	@echo >>$@ "O = Magrathea"
	@echo >>$@ "CN = PKCS7 key 2"
	@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
	@echo >>$@
	@echo >>$@ "[ myexts ]"
	@echo >>$@ "basicConstraints=critical,CA:FALSE"
	@echo >>$@ "keyUsage=digitalSignature"
	@echo >>$@ "subjectKeyIdentifier=hash"
	@echo >>$@ "authorityKeyIdentifier=keyid"

###############################################################################
#
# Generate a couple of signing keys
#
#	openssl x509 -text -inform PEM -noout -in key1.x509
#
###############################################################################
key1.x509: key1.x509_unsigned key4.priv key4.x509
	openssl x509 \
		-req -in key1.x509_unsigned \
		-out key1.x509 \
		-extfile key1.genkey -extensions myexts \
		-CA key4.x509 \
		-CAkey key4.priv \
		-CAcreateserial

key1.priv key1.x509_unsigned: key1.genkey
	openssl req -new -nodes -utf8 -sha1 -days 36500 \
		-batch -outform PEM \
		-config key1.genkey \
		-keyout key1.priv \
		-out key1.x509_unsigned

key1.genkey:
	@echo Generating X.509 key generation config
	@echo  >$@ "[ req ]"
	@echo >>$@ "default_bits = 4096"
	@echo >>$@ "distinguished_name = req_distinguished_name"
	@echo >>$@ "prompt = no"
	@echo >>$@ "string_mask = utf8only"
	@echo >>$@ "x509_extensions = myexts"
	@echo >>$@
	@echo >>$@ "[ req_distinguished_name ]"
	@echo >>$@ "O = Magrathea"
	@echo >>$@ "CN = PKCS7 key 1"
	@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
	@echo >>$@
	@echo >>$@ "[ myexts ]"
	@echo >>$@ "basicConstraints=critical,CA:TRUE"
	@echo >>$@ "keyUsage=digitalSignature,keyCertSign"
	@echo >>$@ "subjectKeyIdentifier=hash"
	@echo >>$@ "authorityKeyIdentifier=keyid"

###############################################################################
#
# Generate a signed key
#
#	openssl x509 -text -inform PEM -noout -in key4.x509
#
###############################################################################
key4.x509: key4.x509_unsigned key3.priv key3.x509
	openssl x509 \
		-req -in key4.x509_unsigned \
		-out key4.x509 \
		-extfile key4.genkey -extensions myexts \
		-CA key3.x509 \
		-CAkey key3.priv \
		-CAcreateserial

key4.priv key4.x509_unsigned: key4.genkey
	openssl req -new -nodes -utf8 -sha1 -days 36500 \
		-batch -outform PEM \
		-config key4.genkey \
		-keyout key4.priv \
		-out key4.x509_unsigned

key4.genkey:
	@echo Generating X.509 key generation config
	@echo  >$@ "[ req ]"
	@echo >>$@ "default_bits = 4096"
	@echo >>$@ "distinguished_name = req_distinguished_name"
	@echo >>$@ "prompt = no"
	@echo >>$@ "string_mask = utf8only"
	@echo >>$@ "x509_extensions = myexts"
	@echo >>$@
	@echo >>$@ "[ req_distinguished_name ]"
	@echo >>$@ "O = Magrathea"
	@echo >>$@ "CN = PKCS7 key 4"
	@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
	@echo >>$@
	@echo >>$@ "[ myexts ]"
	@echo >>$@ "basicConstraints=critical,CA:TRUE"
	@echo >>$@ "keyUsage=digitalSignature,keyCertSign"
	@echo >>$@ "subjectKeyIdentifier=hash"
	@echo >>$@ "authorityKeyIdentifier=keyid"

###############################################################################
#
# Generate a couple of signing keys
#
#	openssl x509 -text -inform PEM -noout -in key3.x509
#
###############################################################################
key3.priv key3.x509: key3.genkey
	openssl req -new -nodes -utf8 -sha1 -days 36500 \
		-batch -x509 -outform PEM \
		-config key3.genkey \
		-keyout key3.priv \
		-out key3.x509

key3.genkey:
	@echo Generating X.509 key generation config
	@echo  >$@ "[ req ]"
	@echo >>$@ "default_bits = 4096"
	@echo >>$@ "distinguished_name = req_distinguished_name"
	@echo >>$@ "prompt = no"
	@echo >>$@ "string_mask = utf8only"
	@echo >>$@ "x509_extensions = myexts"
	@echo >>$@
	@echo >>$@ "[ req_distinguished_name ]"
	@echo >>$@ "O = Magrathea"
	@echo >>$@ "CN = PKCS7 key 3"
	@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
	@echo >>$@
	@echo >>$@ "[ myexts ]"
	@echo >>$@ "basicConstraints=critical,CA:TRUE"
	@echo >>$@ "keyUsage=digitalSignature,keyCertSign"
	@echo >>$@ "subjectKeyIdentifier=hash"
	@echo >>$@ "authorityKeyIdentifier=keyid"

clean:
	$(RM) *~
	$(RM) key1.* key2.* key3.* key4.* stuff.* out certs

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 08815b62
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+13 −0
Original line number Diff line number Diff line
@@ -46,4 +46,17 @@ config PKCS7_MESSAGE_PARSER
	  This option provides support for parsing PKCS#7 format messages for
	  signature data and provides the ability to verify the signature.

config PKCS7_TEST_KEY
	tristate "PKCS#7 testing key type"
	depends on PKCS7_MESSAGE_PARSER
	select SYSTEM_TRUSTED_KEYRING
	help
	  This option provides a type of key that can be loaded up from a
	  PKCS#7 message - provided the message is signed by a trusted key.  If
	  it is, the PKCS#7 wrapper is discarded and reading the key returns
	  just the payload.  If it isn't, adding the key will fail with an
	  error.

	  This is intended for testing the PKCS#7 parser.

endif # ASYMMETRIC_KEY_TYPE
+7 −0
Original line number Diff line number Diff line
@@ -40,3 +40,10 @@ $(obj)/pkcs7_parser.o: $(obj)/pkcs7-asn1.h
$(obj)/pkcs7-asn1.o: $(obj)/pkcs7-asn1.c $(obj)/pkcs7-asn1.h

clean-files	+= pkcs7-asn1.c pkcs7-asn1.h

#
# PKCS#7 parser testing key
#
obj-$(CONFIG_PKCS7_TEST_KEY) += pkcs7_test_key.o
pkcs7_test_key-y := \
	pkcs7_key_type.o
+97 −0
Original line number Diff line number Diff line
/* Testing module to load key from trusted PKCS#7 message
 *
 * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#define pr_fmt(fmt) "PKCS7key: "fmt
#include <linux/key.h>
#include <linux/key-type.h>
#include <crypto/pkcs7.h>
#include <keys/user-type.h>
#include <keys/system_keyring.h>
#include "pkcs7_parser.h"

/*
 * Instantiate a PKCS#7 wrapped and validated key.
 */
int pkcs7_instantiate(struct key *key, struct key_preparsed_payload *prep)
{
	struct pkcs7_message *pkcs7;
	const void *data, *saved_prep_data;
	size_t datalen, saved_prep_datalen;
	bool trusted;
	int ret;

	kenter("");

	saved_prep_data = prep->data;
	saved_prep_datalen = prep->datalen;
	pkcs7 = pkcs7_parse_message(saved_prep_data, saved_prep_datalen);
	if (IS_ERR(pkcs7)) {
		ret = PTR_ERR(pkcs7);
		goto error;
	}

	ret = pkcs7_verify(pkcs7);
	if (ret < 0)
		goto error_free;

	ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
	if (ret < 0)
		goto error_free;
	if (!trusted)
		pr_warn("PKCS#7 message doesn't chain back to a trusted key\n");

	ret = pkcs7_get_content_data(pkcs7, &data, &datalen, false);
	if (ret < 0)
		goto error_free;

	prep->data = data;
	prep->datalen = datalen;
	ret = user_instantiate(key, prep);
	prep->data = saved_prep_data;
	prep->datalen = saved_prep_datalen;

error_free:
	pkcs7_free_message(pkcs7);
error:
	kleave(" = %d", ret);
	return ret;
}

/*
 * user defined keys take an arbitrary string as the description and an
 * arbitrary blob of data as the payload
 */
struct key_type key_type_pkcs7 = {
	.name			= "pkcs7_test",
	.def_lookup_type	= KEYRING_SEARCH_LOOKUP_DIRECT,
	.instantiate		= pkcs7_instantiate,
	.match			= user_match,
	.revoke			= user_revoke,
	.destroy		= user_destroy,
	.describe		= user_describe,
	.read			= user_read,
};

/*
 * Module stuff
 */
static int __init pkcs7_key_init(void)
{
	return register_key_type(&key_type_pkcs7);
}

static void __exit pkcs7_key_cleanup(void)
{
	unregister_key_type(&key_type_pkcs7);
}

module_init(pkcs7_key_init);
module_exit(pkcs7_key_cleanup);