restrict.c | Explore in Territory

// 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 ([email protected])
 */

#define pr_fmt(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 { … } cakey;

static int __init ca_keys_setup(char *str)
{ … }
__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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

static bool match_either_id(const struct asymmetric_key_id **pair,
			    const struct asymmetric_key_id *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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }
linux/crypto/asymmetric_keys/restrict.c
