Commit 22d01afb authored by David Howells's avatar David Howells

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
......@@ -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
......@@ -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
/* 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);
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