[linux-2.6-block.git] / crypto / asymmetric_keys / restrict.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Instantiate a public key crypto key from an X.509 Certificate
 *
 * Copyright (C) 2012, 2016 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define pr_fmt(fmt) "ASYM: "fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <crypto/public_key.h>
#include "asymmetric_keys.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

/**
 * restrict_link_by_signature - Restrict additions to a ring of public keys
 * @dest_keyring: Keyring being linked to.
 * @type: The type of key being added.
 * @payload: The payload of the new key.
 * @trust_keyring: A ring of keys that can be used to vouch for the new cert.
 *
 * 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.
 *
 * Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a
 * matching parent certificate in the trusted list, -EKEYREJECTED if the
 * signature check fails or the key is blacklisted, -ENOPKG if the signature
 * uses unsupported crypto, or some other error if there is a matching
 * certificate but the signature check cannot be performed.
 */
int restrict_link_by_signature(struct key *dest_keyring,
			       const struct key_type *type,
			       const union key_payload *payload,
			       struct key *trust_keyring)
{
	const struct public_key_signature *sig;
	struct key *key;
	int ret;

	pr_devel("==>%s()\n", __func__);

	if (!trust_keyring)
		return -ENOKEY;

	if (type != &key_type_asymmetric)
		return -EOPNOTSUPP;

	sig = payload->data[asym_auth];
	if (!sig)
		return -ENOPKG;
	if (!sig->auth_ids[0] && !sig->auth_ids[1] && !sig->auth_ids[2])
		return -ENOKEY;

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

	/* See if we have a key that signed this one. */
	key = find_asymmetric_key(trust_keyring,
				  sig->auth_ids[0], sig->auth_ids[1],
				  sig->auth_ids[2], false);
	if (IS_ERR(key))
		return -ENOKEY;

	if (use_builtin_keys && !test_bit(KEY_FLAG_BUILTIN, &key->flags))
		ret = -ENOKEY;
	else
		ret = verify_signature(key, sig);
	key_put(key);
	return ret;
}

/**
 * restrict_link_by_ca - Restrict additions to a ring of CA keys
 * @dest_keyring: Keyring being linked to.
 * @type: The type of key being added.
 * @payload: The payload of the new key.
 * @trust_keyring: Unused.
 *
 * Check if the new certificate is a CA. If it is a CA, then mark the new
 * certificate as being ok to link.
 *
 * Returns 0 if the new certificate was accepted, -ENOKEY if the
 * certificate is not a CA. -ENOPKG if the signature uses unsupported
 * crypto, or some other error if there is a matching certificate but
 * the signature check cannot be performed.
 */
int restrict_link_by_ca(struct key *dest_keyring,
			const struct key_type *type,
			const union key_payload *payload,
			struct key *trust_keyring)
{
	const struct public_key *pkey;

	if (type != &key_type_asymmetric)
		return -EOPNOTSUPP;

	pkey = payload->data[asym_crypto];
	if (!pkey)
		return -ENOPKG;
	if (!test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
		return -ENOKEY;
	if (!test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
		return -ENOKEY;
	if (!IS_ENABLED(CONFIG_INTEGRITY_CA_MACHINE_KEYRING_MAX))
		return 0;
	if (test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
		return -ENOKEY;

	return 0;
}

/**
 * restrict_link_by_digsig - Restrict additions to a ring of digsig keys
 * @dest_keyring: Keyring being linked to.
 * @type: The type of key being added.
 * @payload: The payload of the new key.
 * @trust_keyring: A ring of keys that can be used to vouch for the new cert.
 *
 * Check if the new certificate has digitalSignature usage set. If it is,
 * then mark the new certificate as being ok to link. Afterwards verify
 * the new certificate against the ones in the trust_keyring.
 *
 * Returns 0 if the new certificate was accepted, -ENOKEY if the
 * certificate is not a digsig. -ENOPKG if the signature uses unsupported
 * crypto, or some other error if there is a matching certificate but
 * the signature check cannot be performed.
 */
int restrict_link_by_digsig(struct key *dest_keyring,
			    const struct key_type *type,
			    const union key_payload *payload,
			    struct key *trust_keyring)
{
	const struct public_key *pkey;

	if (type != &key_type_asymmetric)
		return -EOPNOTSUPP;

	pkey = payload->data[asym_crypto];

	if (!pkey)
		return -ENOPKG;

	if (!test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
		return -ENOKEY;

	if (test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
		return -ENOKEY;

	if (test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
		return -ENOKEY;

	return restrict_link_by_signature(dest_keyring, type, payload,
					  trust_keyring);
}

static bool match_either_id(const struct asymmetric_key_id **pair,
			    const struct asymmetric_key_id *single)
{
	return (asymmetric_key_id_same(pair[0], single) ||
		asymmetric_key_id_same(pair[1], single));
}

static int key_or_keyring_common(struct key *dest_keyring,
				 const struct key_type *type,
				 const union key_payload *payload,
				 struct key *trusted, bool check_dest)
{
	const struct public_key_signature *sig;
	struct key *key = NULL;
	int ret;

	pr_devel("==>%s()\n", __func__);

	if (!dest_keyring)
		return -ENOKEY;
	else if (dest_keyring->type != &key_type_keyring)
		return -EOPNOTSUPP;

	if (!trusted && !check_dest)
		return -ENOKEY;

	if (type != &key_type_asymmetric)
		return -EOPNOTSUPP;

	sig = payload->data[asym_auth];
	if (!sig)
		return -ENOPKG;
	if (!sig->auth_ids[0] && !sig->auth_ids[1] && !sig->auth_ids[2])
		return -ENOKEY;

	if (trusted) {
		if (trusted->type == &key_type_keyring) {
			/* See if we have a key that signed this one. */
			key = find_asymmetric_key(trusted, sig->auth_ids[0],
						  sig->auth_ids[1],
						  sig->auth_ids[2], false);
			if (IS_ERR(key))
				key = NULL;
		} else if (trusted->type == &key_type_asymmetric) {
			const struct asymmetric_key_id **signer_ids;

			signer_ids = (const struct asymmetric_key_id **)
				asymmetric_key_ids(trusted)->id;

			/*
			 * The auth_ids come from the candidate key (the
			 * one that is being considered for addition to
			 * dest_keyring) and identify the key that was
			 * used to sign.
			 *
			 * The signer_ids are identifiers for the
			 * signing key specified for dest_keyring.
			 *
			 * The first auth_id is the preferred id, 2nd and
			 * 3rd are the fallbacks. If exactly one of
			 * auth_ids[0] and auth_ids[1] is present, it may
			 * match either signer_ids[0] or signed_ids[1].
			 * If both are present the first one may match
			 * either signed_id but the second one must match
			 * the second signer_id. If neither of them is
			 * available, auth_ids[2] is matched against
			 * signer_ids[2] as a fallback.
			 */
			if (!sig->auth_ids[0] && !sig->auth_ids[1]) {
				if (asymmetric_key_id_same(signer_ids[2],
							   sig->auth_ids[2]))
					key = __key_get(trusted);

			} else if (!sig->auth_ids[0] || !sig->auth_ids[1]) {
				const struct asymmetric_key_id *auth_id;

				auth_id = sig->auth_ids[0] ?: sig->auth_ids[1];
				if (match_either_id(signer_ids, auth_id))
					key = __key_get(trusted);

			} else if (asymmetric_key_id_same(signer_ids[1],
							  sig->auth_ids[1]) &&
				   match_either_id(signer_ids,
						   sig->auth_ids[0])) {
				key = __key_get(trusted);
			}
		} else {
			return -EOPNOTSUPP;
		}
	}

	if (check_dest && !key) {
		/* See if the destination has a key that signed this one. */
		key = find_asymmetric_key(dest_keyring, sig->auth_ids[0],
					  sig->auth_ids[1], sig->auth_ids[2],
					  false);
		if (IS_ERR(key))
			key = NULL;
	}

	if (!key)
		return -ENOKEY;

	ret = key_validate(key);
	if (ret == 0)
		ret = verify_signature(key, sig);

	key_put(key);
	return ret;
}

/**
 * restrict_link_by_key_or_keyring - Restrict additions to a ring of public
 * keys using the restrict_key information stored in the ring.
 * @dest_keyring: Keyring being linked to.
 * @type: The type of key being added.
 * @payload: The payload of the new key.
 * @trusted: A key or ring of keys that can be used to vouch for the new cert.
 *
 * Check the new certificate only against the key or keys passed in the data
 * parameter. If one of those is the signing key and validates the new
 * certificate, then mark the new certificate as being ok to link.
 *
 * Returns 0 if the new certificate was accepted, -ENOKEY if we
 * couldn't find a matching parent certificate in the trusted list,
 * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
 * unsupported crypto, or some other error if there is a matching certificate
 * but the signature check cannot be performed.
 */
int restrict_link_by_key_or_keyring(struct key *dest_keyring,
				    const struct key_type *type,
				    const union key_payload *payload,
				    struct key *trusted)
{
	return key_or_keyring_common(dest_keyring, type, payload, trusted,
				     false);
}

/**
 * restrict_link_by_key_or_keyring_chain - Restrict additions to a ring of
 * public keys using the restrict_key information stored in the ring.
 * @dest_keyring: Keyring being linked to.
 * @type: The type of key being added.
 * @payload: The payload of the new key.
 * @trusted: A key or ring of keys that can be used to vouch for the new cert.
 *
 * Check the new certificate against the key or keys passed in the data
 * parameter and against the keys already linked to the destination keyring. If
 * one of those is the signing key and validates the new certificate, then mark
 * the new certificate as being ok to link.
 *
 * Returns 0 if the new certificate was accepted, -ENOKEY if we
 * couldn't find a matching parent certificate in the trusted list,
 * -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
 * unsupported crypto, or some other error if there is a matching certificate
 * but the signature check cannot be performed.
 */
int restrict_link_by_key_or_keyring_chain(struct key *dest_keyring,
					  const struct key_type *type,
					  const union key_payload *payload,
					  struct key *trusted)
{
	return key_or_keyring_common(dest_keyring, type, payload, trusted,
				     true);
}
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
cfb664ff DH	2	/* Instantiate a public key crypto key from an X.509 Certificate
cfb664ff DH	3	*
a511e1af	4	* Copyright (C) 2012, 2016 Red Hat, Inc. All Rights Reserved.
cfb664ff	5	* Written by David Howells (dhowells@redhat.com)
cfb664ff DH	6	*/
cfb664ff DH	7
a511e1af	8	#define pr_fmt(fmt) "ASYM: "fmt
cfb664ff DH	9	#include <linux/module.h>
cfb664ff DH	10	#include <linux/kernel.h>
cfb664ff	11	#include <linux/err.h>
cfb664ff DH	12	#include <crypto/public_key.h>
cfb664ff DH	13	#include "asymmetric_keys.h"
cfb664ff DH	14
	15	static bool use_builtin_keys;
	16	static struct asymmetric_key_id *ca_keyid;
	17
	18	#ifndef MODULE
	19	static struct {
	20	struct asymmetric_key_id id;
	21	unsigned char data[10];
	22	} cakey;
	23
	24	static int __init ca_keys_setup(char *str)
	25	{
	26	if (!str) /* default system keyring */
	27	return 1;
	28
	29	if (strncmp(str, "id:", 3) == 0) {
	30	struct asymmetric_key_id *p = &cakey.id;
	31	size_t hexlen = (strlen(str) - 3) / 2;
	32	int ret;
	33
	34	if (hexlen == 0 \|\| hexlen > sizeof(cakey.data)) {
	35	pr_err("Missing or invalid ca_keys id\n");
	36	return 1;
	37	}
	38
	39	ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);
	40	if (ret < 0)
	41	pr_err("Unparsable ca_keys id hex string\n");
	42	else
	43	ca_keyid = p; /* owner key 'id:xxxxxx' */
	44	} else if (strcmp(str, "builtin") == 0) {
	45	use_builtin_keys = true;
	46	}
	47
	48	return 1;
	49	}
	50	__setup("ca_keys=", ca_keys_setup);
	51	#endif
	52
a511e1af DH	53	/**
a511e1af DH	54	* restrict_link_by_signature - Restrict additions to a ring of public keys
aaf66c88	55	* @dest_keyring: Keyring being linked to.
a511e1af DH	56	* @type: The type of key being added.
a511e1af DH	57	* @payload: The payload of the new key.
aaf66c88	58	* @trust_keyring: A ring of keys that can be used to vouch for the new cert.
a511e1af	59	*
cfb664ff DH	60	* Check the new certificate against the ones in the trust keyring. If one of
	61	* those is the signing key and validates the new certificate, then mark the
	62	* new certificate as being trusted.
	63	*
a511e1af DH	64	* Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a
a511e1af DH	65	* matching parent certificate in the trusted list, -EKEYREJECTED if the
4b34968e EB	66	* signature check fails or the key is blacklisted, -ENOPKG if the signature
	67	* uses unsupported crypto, or some other error if there is a matching
	68	* certificate but the signature check cannot be performed.
cfb664ff	69	*/
aaf66c88	70	int restrict_link_by_signature(struct key *dest_keyring,
a511e1af	71	const struct key_type *type,
aaf66c88 MM	72	const union key_payload *payload,
aaf66c88 MM	73	struct key *trust_keyring)
cfb664ff	74	{
a511e1af	75	const struct public_key_signature *sig;
cfb664ff	76	struct key *key;
a511e1af	77	int ret;
cfb664ff	78
a511e1af	79	pr_devel("==>%s()\n", __func__);
cfb664ff DH	80
cfb664ff DH	81	if (!trust_keyring)
a511e1af DH	82	return -ENOKEY;
	83
	84	if (type != &key_type_asymmetric)
cfb664ff	85	return -EOPNOTSUPP;
a511e1af DH	86
a511e1af DH	87	sig = payload->data[asym_auth];
4b34968e EB	88	if (!sig)
4b34968e EB	89	return -ENOPKG;
7d30198e	90	if (!sig->auth_ids[0] && !sig->auth_ids[1] && !sig->auth_ids[2])
acddc720	91	return -ENOKEY;
a511e1af	92
cfb664ff DH	93	if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid))
cfb664ff DH	94	return -EPERM;
cfb664ff	95
a511e1af	96	/* See if we have a key that signed this one. */
cfb664ff DH	97	key = find_asymmetric_key(trust_keyring,
cfb664ff DH	98	sig->auth_ids[0], sig->auth_ids[1],
7d30198e	99	sig->auth_ids[2], false);
cfb664ff	100	if (IS_ERR(key))
a511e1af	101	return -ENOKEY;
cfb664ff	102
a511e1af DH	103	if (use_builtin_keys && !test_bit(KEY_FLAG_BUILTIN, &key->flags))
	104	ret = -ENOKEY;
	105	else
	106	ret = verify_signature(key, sig);
cfb664ff DH	107	key_put(key);
	108	return ret;
	109	}
7e3c4d22	110
76adb2fb ES	111	/**
	112	* restrict_link_by_ca - Restrict additions to a ring of CA keys
	113	* @dest_keyring: Keyring being linked to.
	114	* @type: The type of key being added.
	115	* @payload: The payload of the new key.
	116	* @trust_keyring: Unused.
	117	*
	118	* Check if the new certificate is a CA. If it is a CA, then mark the new
	119	* certificate as being ok to link.
	120	*
	121	* Returns 0 if the new certificate was accepted, -ENOKEY if the
	122	* certificate is not a CA. -ENOPKG if the signature uses unsupported
	123	* crypto, or some other error if there is a matching certificate but
	124	* the signature check cannot be performed.
	125	*/
	126	int restrict_link_by_ca(struct key *dest_keyring,
	127	const struct key_type *type,
	128	const union key_payload *payload,
	129	struct key *trust_keyring)
	130	{
	131	const struct public_key *pkey;
	132
	133	if (type != &key_type_asymmetric)
	134	return -EOPNOTSUPP;
	135
	136	pkey = payload->data[asym_crypto];
	137	if (!pkey)
	138	return -ENOPKG;
	139	if (!test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
	140	return -ENOKEY;
	141	if (!test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
	142	return -ENOKEY;
099f26f2 ES	143	if (!IS_ENABLED(CONFIG_INTEGRITY_CA_MACHINE_KEYRING_MAX))
099f26f2 ES	144	return 0;
76adb2fb ES	145	if (test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
	146	return -ENOKEY;
	147
	148	return 0;
	149	}
	150
4cfb9080 ES	151	/**
	152	* restrict_link_by_digsig - Restrict additions to a ring of digsig keys
	153	* @dest_keyring: Keyring being linked to.
	154	* @type: The type of key being added.
	155	* @payload: The payload of the new key.
	156	* @trust_keyring: A ring of keys that can be used to vouch for the new cert.
	157	*
	158	* Check if the new certificate has digitalSignature usage set. If it is,
	159	* then mark the new certificate as being ok to link. Afterwards verify
	160	* the new certificate against the ones in the trust_keyring.
	161	*
	162	* Returns 0 if the new certificate was accepted, -ENOKEY if the
	163	* certificate is not a digsig. -ENOPKG if the signature uses unsupported
	164	* crypto, or some other error if there is a matching certificate but
	165	* the signature check cannot be performed.
	166	*/
	167	int restrict_link_by_digsig(struct key *dest_keyring,
	168	const struct key_type *type,
	169	const union key_payload *payload,
	170	struct key *trust_keyring)
	171	{
	172	const struct public_key *pkey;
	173
	174	if (type != &key_type_asymmetric)
	175	return -EOPNOTSUPP;
	176
	177	pkey = payload->data[asym_crypto];
	178
	179	if (!pkey)
	180	return -ENOPKG;
	181
	182	if (!test_bit(KEY_EFLAG_DIGITALSIG, &pkey->key_eflags))
	183	return -ENOKEY;
	184
	185	if (test_bit(KEY_EFLAG_CA, &pkey->key_eflags))
	186	return -ENOKEY;
	187
	188	if (test_bit(KEY_EFLAG_KEYCERTSIGN, &pkey->key_eflags))
	189	return -ENOKEY;
	190
	191	return restrict_link_by_signature(dest_keyring, type, payload,
	192	trust_keyring);
	193	}
	194
7d30198e	195	static bool match_either_id(const struct asymmetric_key_id **pair,
8e323a02 MM	196	const struct asymmetric_key_id *single)
8e323a02 MM	197	{
7d30198e AZ	198	return (asymmetric_key_id_same(pair[0], single) \|\|
7d30198e AZ	199	asymmetric_key_id_same(pair[1], single));
8e323a02 MM	200	}
	201
	202	static int key_or_keyring_common(struct key *dest_keyring,
	203	const struct key_type *type,
	204	const union key_payload *payload,
	205	struct key *trusted, bool check_dest)
7e3c4d22 MM	206	{
7e3c4d22 MM	207	const struct public_key_signature *sig;
8e323a02	208	struct key *key = NULL;
7e3c4d22 MM	209	int ret;
	210
	211	pr_devel("==>%s()\n", __func__);
	212
	213	if (!dest_keyring)
	214	return -ENOKEY;
	215	else if (dest_keyring->type != &key_type_keyring)
	216	return -EOPNOTSUPP;
	217
8e323a02	218	if (!trusted && !check_dest)
7e3c4d22 MM	219	return -ENOKEY;
	220
	221	if (type != &key_type_asymmetric)
	222	return -EOPNOTSUPP;
	223
	224	sig = payload->data[asym_auth];
4b34968e EB	225	if (!sig)
4b34968e EB	226	return -ENOPKG;
7d30198e	227	if (!sig->auth_ids[0] && !sig->auth_ids[1] && !sig->auth_ids[2])
7e3c4d22 MM	228	return -ENOKEY;
7e3c4d22 MM	229
8e323a02 MM	230	if (trusted) {
	231	if (trusted->type == &key_type_keyring) {
	232	/* See if we have a key that signed this one. */
	233	key = find_asymmetric_key(trusted, sig->auth_ids[0],
7d30198e AZ	234	sig->auth_ids[1],
7d30198e AZ	235	sig->auth_ids[2], false);
8e323a02 MM	236	if (IS_ERR(key))
	237	key = NULL;
	238	} else if (trusted->type == &key_type_asymmetric) {
7d30198e	239	const struct asymmetric_key_id **signer_ids;
7e3c4d22	240
7d30198e AZ	241	signer_ids = (const struct asymmetric_key_id **)
7d30198e AZ	242	asymmetric_key_ids(trusted)->id;
7e3c4d22	243
8e323a02 MM	244	/*
	245	* The auth_ids come from the candidate key (the
	246	* one that is being considered for addition to
	247	* dest_keyring) and identify the key that was
	248	* used to sign.
	249	*
	250	* The signer_ids are identifiers for the
	251	* signing key specified for dest_keyring.
	252	*
7d30198e AZ	253	* The first auth_id is the preferred id, 2nd and
	254	* 3rd are the fallbacks. If exactly one of
	255	* auth_ids[0] and auth_ids[1] is present, it may
	256	* match either signer_ids[0] or signed_ids[1].
	257	* If both are present the first one may match
	258	* either signed_id but the second one must match
	259	* the second signer_id. If neither of them is
	260	* available, auth_ids[2] is matched against
	261	* signer_ids[2] as a fallback.
8e323a02	262	*/
7d30198e AZ	263	if (!sig->auth_ids[0] && !sig->auth_ids[1]) {
	264	if (asymmetric_key_id_same(signer_ids[2],
	265	sig->auth_ids[2]))
	266	key = __key_get(trusted);
	267
	268	} else if (!sig->auth_ids[0] \|\| !sig->auth_ids[1]) {
8e323a02	269	const struct asymmetric_key_id *auth_id;
7e3c4d22	270
8e323a02 MM	271	auth_id = sig->auth_ids[0] ?: sig->auth_ids[1];
	272	if (match_either_id(signer_ids, auth_id))
	273	key = __key_get(trusted);
	274
7d30198e	275	} else if (asymmetric_key_id_same(signer_ids[1],
8e323a02 MM	276	sig->auth_ids[1]) &&
	277	match_either_id(signer_ids,
	278	sig->auth_ids[0])) {
	279	key = __key_get(trusted);
	280	}
	281	} else {
	282	return -EOPNOTSUPP;
	283	}
7e3c4d22 MM	284	}
7e3c4d22 MM	285
8e323a02 MM	286	if (check_dest && !key) {
	287	/* See if the destination has a key that signed this one. */
	288	key = find_asymmetric_key(dest_keyring, sig->auth_ids[0],
7d30198e AZ	289	sig->auth_ids[1], sig->auth_ids[2],
7d30198e AZ	290	false);
8e323a02 MM	291	if (IS_ERR(key))
	292	key = NULL;
	293	}
	294
	295	if (!key)
	296	return -ENOKEY;
	297
7e3c4d22 MM	298	ret = key_validate(key);
	299	if (ret == 0)
	300	ret = verify_signature(key, sig);
	301
	302	key_put(key);
	303	return ret;
	304	}
8e323a02 MM	305
	306	/**
	307	* restrict_link_by_key_or_keyring - Restrict additions to a ring of public
	308	* keys using the restrict_key information stored in the ring.
	309	* @dest_keyring: Keyring being linked to.
	310	* @type: The type of key being added.
	311	* @payload: The payload of the new key.
	312	* @trusted: A key or ring of keys that can be used to vouch for the new cert.
	313	*
	314	* Check the new certificate only against the key or keys passed in the data
	315	* parameter. If one of those is the signing key and validates the new
	316	* certificate, then mark the new certificate as being ok to link.
	317	*
	318	* Returns 0 if the new certificate was accepted, -ENOKEY if we
	319	* couldn't find a matching parent certificate in the trusted list,
4b34968e EB	320	* -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
	321	* unsupported crypto, or some other error if there is a matching certificate
	322	* but the signature check cannot be performed.
8e323a02 MM	323	*/
	324	int restrict_link_by_key_or_keyring(struct key *dest_keyring,
	325	const struct key_type *type,
	326	const union key_payload *payload,
	327	struct key *trusted)
	328	{
	329	return key_or_keyring_common(dest_keyring, type, payload, trusted,
	330	false);
	331	}
	332
	333	/**
	334	* restrict_link_by_key_or_keyring_chain - Restrict additions to a ring of
	335	* public keys using the restrict_key information stored in the ring.
	336	* @dest_keyring: Keyring being linked to.
	337	* @type: The type of key being added.
	338	* @payload: The payload of the new key.
	339	* @trusted: A key or ring of keys that can be used to vouch for the new cert.
	340	*
40d32b59 AZ	341	* Check the new certificate against the key or keys passed in the data
	342	* parameter and against the keys already linked to the destination keyring. If
	343	* one of those is the signing key and validates the new certificate, then mark
	344	* the new certificate as being ok to link.
8e323a02 MM	345	*
	346	* Returns 0 if the new certificate was accepted, -ENOKEY if we
	347	* couldn't find a matching parent certificate in the trusted list,
4b34968e EB	348	* -EKEYREJECTED if the signature check fails, -ENOPKG if the signature uses
	349	* unsupported crypto, or some other error if there is a matching certificate
	350	* but the signature check cannot be performed.
8e323a02 MM	351	*/
	352	int restrict_link_by_key_or_keyring_chain(struct key *dest_keyring,
	353	const struct key_type *type,
	354	const union key_payload *payload,
	355	struct key *trusted)
	356	{
	357	return key_or_keyring_common(dest_keyring, type, payload, trusted,
	358	true);
	359	}