276 lines
8.3 KiB
C
276 lines
8.3 KiB
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;
|
|
}
|
|
|
|
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);
|
|
}
|