diff options
Diffstat (limited to 'drivers/nvme/common/keyring.c')
| -rw-r--r-- | drivers/nvme/common/keyring.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/drivers/nvme/common/keyring.c b/drivers/nvme/common/keyring.c new file mode 100644 index 000000000..ee341b83e --- /dev/null +++ b/drivers/nvme/common/keyring.c @@ -0,0 +1,185 @@ +// 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. + */ +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_init(nvme_keyring_init); +module_exit(nvme_keyring_exit); |