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Commit cfb664ff authored by David Howells's avatar David Howells
Browse files

X.509: Move the trust validation code out to its own file 



Move the X.509 trust validation code out to its own file so that it can be
generalised.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 5f7f5c81

crypto/asymmetric_keys/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -4,7 +4,10 @@ 


obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys.o



asymmetric_keys-y := asymmetric_type.o signature.o

asymmetric_keys-y := \

	asymmetric_type.o \

	restrict.o \

	signature.o



obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o

crypto/asymmetric_keys/restrict.c

0 → 100644
+106 −0
Original line number Diff line number Diff line 
/* Instantiate a public key crypto key from an X.509 Certificate

 *

 * Copyright (C) 2012 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) "X.509: "fmt

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/err.h>

#include <linux/mpi.h>

#include <linux/asn1_decoder.h>

#include <keys/asymmetric-subtype.h>

#include <keys/asymmetric-parser.h>

#include <keys/system_keyring.h>

#include <crypto/hash.h>

#include <crypto/public_key.h>

#include "asymmetric_keys.h"

#include "x509_parser.h"



static bool use_builtin_keys;

static struct asymmetric_key_id *ca_keyid;



#ifndef MODULE

static struct {

	struct asymmetric_key_id id;

	unsigned char data[10];

} cakey;



static int __init ca_keys_setup(char *str)

{

	if (!str)		/* default system keyring */

		return 1;



	if (strncmp(str, "id:", 3) == 0) {

		struct asymmetric_key_id *p = &cakey.id;

		size_t hexlen = (strlen(str) - 3) / 2;

		int ret;



		if (hexlen == 0 || hexlen > sizeof(cakey.data)) {

			pr_err("Missing or invalid ca_keys id\n");

			return 1;

		}



		ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);

		if (ret < 0)

			pr_err("Unparsable ca_keys id hex string\n");

		else

			ca_keyid = p;	/* owner key 'id:xxxxxx' */

	} else if (strcmp(str, "builtin") == 0) {

		use_builtin_keys = true;

	}



	return 1;

}

__setup("ca_keys=", ca_keys_setup);

#endif



/*

 * Check the new certificate against the ones in the trust keyring.  If one of

 * those is the signing key and validates the new certificate, then mark the

 * new certificate as being trusted.

 *

 * Return 0 if the new certificate was successfully validated, 1 if we couldn't

 * find a matching parent certificate in the trusted list and an error if there

 * is a matching certificate but the signature check fails.

 */

int x509_validate_trust(struct x509_certificate *cert,

			struct key *trust_keyring)

{

	struct public_key_signature *sig = cert->sig;

	struct key *key;

	int ret = 1;



	if (!sig->auth_ids[0] && !sig->auth_ids[1])

		return 1;



	if (!trust_keyring)

		return -EOPNOTSUPP;

	if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid))

		return -EPERM;

	if (cert->unsupported_sig)

		return -ENOPKG;



	key = find_asymmetric_key(trust_keyring,

				  sig->auth_ids[0], sig->auth_ids[1],

				  false);

	if (IS_ERR(key))

		return PTR_ERR(key);



	if (!use_builtin_keys ||

	    test_bit(KEY_FLAG_BUILTIN, &key->flags)) {

		ret = verify_signature(key, cert->sig);

		if (ret == -ENOPKG)

			cert->unsupported_sig = true;

	}

	key_put(key);

	return ret;

}

EXPORT_SYMBOL_GPL(x509_validate_trust);

crypto/asymmetric_keys/x509_parser.h

+6 −0
Original line number Diff line number Diff line
@@ -58,3 +58,9 @@ extern int x509_decode_time(time64_t *_t, size_t hdrlen, 
 */

extern int x509_get_sig_params(struct x509_certificate *cert);

extern int x509_check_for_self_signed(struct x509_certificate *cert);



/*

 * public_key_trust.c

 */

extern int x509_validate_trust(struct x509_certificate *cert,

			       struct key *trust_keyring);

crypto/asymmetric_keys/x509_public_key.c

+0 −79
Original line number Diff line number Diff line
@@ -20,44 +20,6 @@ 
#include "asymmetric_keys.h"

#include "x509_parser.h"



static bool use_builtin_keys;

static struct asymmetric_key_id *ca_keyid;



#ifndef MODULE

static struct {

	struct asymmetric_key_id id;

	unsigned char data[10];

} cakey;



static int __init ca_keys_setup(char *str)

{

	if (!str)		/* default system keyring */

		return 1;



	if (strncmp(str, "id:", 3) == 0) {

		struct asymmetric_key_id *p = &cakey.id;

		size_t hexlen = (strlen(str) - 3) / 2;

		int ret;



		if (hexlen == 0 || hexlen > sizeof(cakey.data)) {

			pr_err("Missing or invalid ca_keys id\n");

			return 1;

		}



		ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);

		if (ret < 0)

			pr_err("Unparsable ca_keys id hex string\n");

		else

			ca_keyid = p;	/* owner key 'id:xxxxxx' */

	} else if (strcmp(str, "builtin") == 0) {

		use_builtin_keys = true;

	}



	return 1;

}

__setup("ca_keys=", ca_keys_setup);

#endif



/*

 * Set up the signature parameters in an X.509 certificate.  This involves

 * digesting the signed data and extracting the signature.
@@ -187,47 +149,6 @@ int x509_check_for_self_signed(struct x509_certificate *cert) 
	return 0;

}



/*

 * Check the new certificate against the ones in the trust keyring.  If one of

 * those is the signing key and validates the new certificate, then mark the

 * new certificate as being trusted.

 *

 * Return 0 if the new certificate was successfully validated, 1 if we couldn't

 * find a matching parent certificate in the trusted list and an error if there

 * is a matching certificate but the signature check fails.

 */

static int x509_validate_trust(struct x509_certificate *cert,

			       struct key *trust_keyring)

{

	struct public_key_signature *sig = cert->sig;

	struct key *key;

	int ret = 1;



	if (!sig->auth_ids[0] && !sig->auth_ids[1])

		return 1;



	if (!trust_keyring)

		return -EOPNOTSUPP;

	if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid))

		return -EPERM;

	if (cert->unsupported_sig)

		return -ENOPKG;



	key = find_asymmetric_key(trust_keyring,

				  sig->auth_ids[0], sig->auth_ids[1], false);

	if (IS_ERR(key))

		return PTR_ERR(key);



	if (!use_builtin_keys ||

	    test_bit(KEY_FLAG_BUILTIN, &key->flags)) {

		ret = verify_signature(key, cert->sig);

		if (ret == -ENOPKG)

			cert->unsupported_sig = true;

	}

	key_put(key);

	return ret;

}



/*

 * Attempt to parse a data blob for a key as an X509 certificate.

 */