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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2023 Hannes Reinecke, SUSE Labs
*/
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/key.h>
#include <linux/key-type.h>
#include <keys/user-type.h>
#include <linux/nvme.h>
#include <linux/nvme-tcp.h>
#include <linux/nvme-keyring.h>
static struct key *nvme_keyring;
key_serial_t nvme_keyring_id(void)
{
return nvme_keyring->serial;
}
EXPORT_SYMBOL_GPL(nvme_keyring_id);
static void nvme_tls_psk_describe(const struct key *key, struct seq_file *m)
{
seq_puts(m, key->description);
seq_printf(m, ": %u", key->datalen);
}
static bool nvme_tls_psk_match(const struct key *key,
const struct key_match_data *match_data)
{
const char *match_id;
size_t match_len;
if (!key->description) {
pr_debug("%s: no key description\n", __func__);
return false;
}
match_len = strlen(key->description);
pr_debug("%s: id %s len %zd\n", __func__, key->description, match_len);
if (!match_data->raw_data) {
pr_debug("%s: no match data\n", __func__);
return false;
}
match_id = match_data->raw_data;
pr_debug("%s: match '%s' '%s' len %zd\n",
__func__, match_id, key->description, match_len);
return !memcmp(key->description, match_id, match_len);
}
static int nvme_tls_psk_match_preparse(struct key_match_data *match_data)
{
match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
match_data->cmp = nvme_tls_psk_match;
return 0;
}
static struct key_type nvme_tls_psk_key_type = {
.name = "psk",
.flags = KEY_TYPE_NET_DOMAIN,
.preparse = user_preparse,
.free_preparse = user_free_preparse,
.match_preparse = nvme_tls_psk_match_preparse,
.instantiate = generic_key_instantiate,
.revoke = user_revoke,
.destroy = user_destroy,
.describe = nvme_tls_psk_describe,
.read = user_read,
};
static struct key *nvme_tls_psk_lookup(struct key *keyring,
const char *hostnqn, const char *subnqn,
int hmac, bool generated)
{
char *identity;
size_t identity_len = (NVMF_NQN_SIZE) * 2 + 11;
key_ref_t keyref;
key_serial_t keyring_id;
identity = kzalloc(identity_len, GFP_KERNEL);
if (!identity)
return ERR_PTR(-ENOMEM);
snprintf(identity, identity_len, "NVMe0%c%02d %s %s",
generated ? 'G' : 'R', hmac, hostnqn, subnqn);
if (!keyring)
keyring = nvme_keyring;
keyring_id = key_serial(keyring);
pr_debug("keyring %x lookup tls psk '%s'\n",
keyring_id, identity);
keyref = keyring_search(make_key_ref(keyring, true),
&nvme_tls_psk_key_type,
identity, false);
if (IS_ERR(keyref)) {
pr_debug("lookup tls psk '%s' failed, error %ld\n",
identity, PTR_ERR(keyref));
kfree(identity);
return ERR_PTR(-ENOKEY);
}
kfree(identity);
return key_ref_to_ptr(keyref);
}
/*
* NVMe PSK priority list
*
* 'Retained' PSKs (ie 'generated == false')
* should be preferred to 'generated' PSKs,
* and SHA-384 should be preferred to SHA-256.
*/
static struct nvme_tls_psk_priority_list {
bool generated;
enum nvme_tcp_tls_cipher cipher;
} nvme_tls_psk_prio[] = {
{ .generated = false,
.cipher = NVME_TCP_TLS_CIPHER_SHA384, },
{ .generated = false,
.cipher = NVME_TCP_TLS_CIPHER_SHA256, },
{ .generated = true,
.cipher = NVME_TCP_TLS_CIPHER_SHA384, },
{ .generated = true,
.cipher = NVME_TCP_TLS_CIPHER_SHA256, },
};
/*
* nvme_tls_psk_default - Return the preferred PSK to use for TLS ClientHello
*/
key_serial_t nvme_tls_psk_default(struct key *keyring,
const char *hostnqn, const char *subnqn)
{
struct key *tls_key;
key_serial_t tls_key_id;
int prio;
for (prio = 0; prio < ARRAY_SIZE(nvme_tls_psk_prio); prio++) {
bool generated = nvme_tls_psk_prio[prio].generated;
enum nvme_tcp_tls_cipher cipher = nvme_tls_psk_prio[prio].cipher;
tls_key = nvme_tls_psk_lookup(keyring, hostnqn, subnqn,
cipher, generated);
if (!IS_ERR(tls_key)) {
tls_key_id = tls_key->serial;
key_put(tls_key);
return tls_key_id;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(nvme_tls_psk_default);
static int __init nvme_keyring_init(void)
{
int err;
nvme_keyring = keyring_alloc(".nvme",
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
current_cred(),
(KEY_POS_ALL & ~KEY_POS_SETATTR) |
(KEY_USR_ALL & ~KEY_USR_SETATTR),
KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
if (IS_ERR(nvme_keyring))
return PTR_ERR(nvme_keyring);
err = register_key_type(&nvme_tls_psk_key_type);
if (err) {
key_put(nvme_keyring);
return err;
}
return 0;
}
static void __exit nvme_keyring_exit(void)
{
unregister_key_type(&nvme_tls_psk_key_type);
key_revoke(nvme_keyring);
key_put(nvme_keyring);
}
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
MODULE_DESCRIPTION("NVMe Keyring implementation");
module_init(nvme_keyring_init);
module_exit(nvme_keyring_exit);
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