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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
| 2 | +/* |
| 3 | + * Copyright (c) 2023 Hannes Reinecke, SUSE Labs |
| 4 | + */ |
| 5 | + |
| 6 | +#include <linux/module.h> |
| 7 | +#include <linux/seq_file.h> |
| 8 | +#include <linux/key.h> |
| 9 | +#include <linux/key-type.h> |
| 10 | +#include <keys/user-type.h> |
| 11 | +#include <linux/nvme.h> |
| 12 | +#include <linux/nvme-tcp.h> |
| 13 | +#include <linux/nvme-keyring.h> |
| 14 | + |
| 15 | +static struct key *nvme_keyring; |
| 16 | + |
| 17 | +key_serial_t nvme_keyring_id(void) |
| 18 | +{ |
| 19 | + return nvme_keyring->serial; |
| 20 | +} |
| 21 | +EXPORT_SYMBOL_GPL(nvme_keyring_id); |
| 22 | + |
| 23 | +static void nvme_tls_psk_describe(const struct key *key, struct seq_file *m) |
| 24 | +{ |
| 25 | + seq_puts(m, key->description); |
| 26 | + seq_printf(m, ": %u", key->datalen); |
| 27 | +} |
| 28 | + |
| 29 | +static bool nvme_tls_psk_match(const struct key *key, |
| 30 | + const struct key_match_data *match_data) |
| 31 | +{ |
| 32 | + const char *match_id; |
| 33 | + size_t match_len; |
| 34 | + |
| 35 | + if (!key->description) { |
| 36 | + pr_debug("%s: no key description\n", __func__); |
| 37 | + return false; |
| 38 | + } |
| 39 | + match_len = strlen(key->description); |
| 40 | + pr_debug("%s: id %s len %zd\n", __func__, key->description, match_len); |
| 41 | + |
| 42 | + if (!match_data->raw_data) { |
| 43 | + pr_debug("%s: no match data\n", __func__); |
| 44 | + return false; |
| 45 | + } |
| 46 | + match_id = match_data->raw_data; |
| 47 | + pr_debug("%s: match '%s' '%s' len %zd\n", |
| 48 | + __func__, match_id, key->description, match_len); |
| 49 | + return !memcmp(key->description, match_id, match_len); |
| 50 | +} |
| 51 | + |
| 52 | +static int nvme_tls_psk_match_preparse(struct key_match_data *match_data) |
| 53 | +{ |
| 54 | + match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE; |
| 55 | + match_data->cmp = nvme_tls_psk_match; |
| 56 | + return 0; |
| 57 | +} |
| 58 | + |
| 59 | +static struct key_type nvme_tls_psk_key_type = { |
| 60 | + .name = "psk", |
| 61 | + .flags = KEY_TYPE_NET_DOMAIN, |
| 62 | + .preparse = user_preparse, |
| 63 | + .free_preparse = user_free_preparse, |
| 64 | + .match_preparse = nvme_tls_psk_match_preparse, |
| 65 | + .instantiate = generic_key_instantiate, |
| 66 | + .revoke = user_revoke, |
| 67 | + .destroy = user_destroy, |
| 68 | + .describe = nvme_tls_psk_describe, |
| 69 | + .read = user_read, |
| 70 | +}; |
| 71 | + |
| 72 | +static struct key *nvme_tls_psk_lookup(struct key *keyring, |
| 73 | + const char *hostnqn, const char *subnqn, |
| 74 | + int hmac, bool generated) |
| 75 | +{ |
| 76 | + char *identity; |
| 77 | + size_t identity_len = (NVMF_NQN_SIZE) * 2 + 11; |
| 78 | + key_ref_t keyref; |
| 79 | + key_serial_t keyring_id; |
| 80 | + |
| 81 | + identity = kzalloc(identity_len, GFP_KERNEL); |
| 82 | + if (!identity) |
| 83 | + return ERR_PTR(-ENOMEM); |
| 84 | + |
| 85 | + snprintf(identity, identity_len, "NVMe0%c%02d %s %s", |
| 86 | + generated ? 'G' : 'R', hmac, hostnqn, subnqn); |
| 87 | + |
| 88 | + if (!keyring) |
| 89 | + keyring = nvme_keyring; |
| 90 | + keyring_id = key_serial(keyring); |
| 91 | + pr_debug("keyring %x lookup tls psk '%s'\n", |
| 92 | + keyring_id, identity); |
| 93 | + keyref = keyring_search(make_key_ref(keyring, true), |
| 94 | + &nvme_tls_psk_key_type, |
| 95 | + identity, false); |
| 96 | + if (IS_ERR(keyref)) { |
| 97 | + pr_debug("lookup tls psk '%s' failed, error %ld\n", |
| 98 | + identity, PTR_ERR(keyref)); |
| 99 | + kfree(identity); |
| 100 | + return ERR_PTR(-ENOKEY); |
| 101 | + } |
| 102 | + kfree(identity); |
| 103 | + |
| 104 | + return key_ref_to_ptr(keyref); |
| 105 | +} |
| 106 | + |
| 107 | +/* |
| 108 | + * NVMe PSK priority list |
| 109 | + * |
| 110 | + * 'Retained' PSKs (ie 'generated == false') |
| 111 | + * should be preferred to 'generated' PSKs, |
| 112 | + * and SHA-384 should be preferred to SHA-256. |
| 113 | + */ |
| 114 | +struct nvme_tls_psk_priority_list { |
| 115 | + bool generated; |
| 116 | + enum nvme_tcp_tls_cipher cipher; |
| 117 | +} nvme_tls_psk_prio[] = { |
| 118 | + { .generated = false, |
| 119 | + .cipher = NVME_TCP_TLS_CIPHER_SHA384, }, |
| 120 | + { .generated = false, |
| 121 | + .cipher = NVME_TCP_TLS_CIPHER_SHA256, }, |
| 122 | + { .generated = true, |
| 123 | + .cipher = NVME_TCP_TLS_CIPHER_SHA384, }, |
| 124 | + { .generated = true, |
| 125 | + .cipher = NVME_TCP_TLS_CIPHER_SHA256, }, |
| 126 | +}; |
| 127 | + |
| 128 | +/* |
| 129 | + * nvme_tls_psk_default - Return the preferred PSK to use for TLS ClientHello |
| 130 | + */ |
| 131 | +key_serial_t nvme_tls_psk_default(struct key *keyring, |
| 132 | + const char *hostnqn, const char *subnqn) |
| 133 | +{ |
| 134 | + struct key *tls_key; |
| 135 | + key_serial_t tls_key_id; |
| 136 | + int prio; |
| 137 | + |
| 138 | + for (prio = 0; prio < ARRAY_SIZE(nvme_tls_psk_prio); prio++) { |
| 139 | + bool generated = nvme_tls_psk_prio[prio].generated; |
| 140 | + enum nvme_tcp_tls_cipher cipher = nvme_tls_psk_prio[prio].cipher; |
| 141 | + |
| 142 | + tls_key = nvme_tls_psk_lookup(keyring, hostnqn, subnqn, |
| 143 | + cipher, generated); |
| 144 | + if (!IS_ERR(tls_key)) { |
| 145 | + tls_key_id = tls_key->serial; |
| 146 | + key_put(tls_key); |
| 147 | + return tls_key_id; |
| 148 | + } |
| 149 | + } |
| 150 | + return 0; |
| 151 | +} |
| 152 | +EXPORT_SYMBOL_GPL(nvme_tls_psk_default); |
| 153 | + |
| 154 | +int nvme_keyring_init(void) |
| 155 | +{ |
| 156 | + int err; |
| 157 | + |
| 158 | + nvme_keyring = keyring_alloc(".nvme", |
| 159 | + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, |
| 160 | + current_cred(), |
| 161 | + (KEY_POS_ALL & ~KEY_POS_SETATTR) | |
| 162 | + (KEY_USR_ALL & ~KEY_USR_SETATTR), |
| 163 | + KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL); |
| 164 | + if (IS_ERR(nvme_keyring)) |
| 165 | + return PTR_ERR(nvme_keyring); |
| 166 | + |
| 167 | + err = register_key_type(&nvme_tls_psk_key_type); |
| 168 | + if (err) { |
| 169 | + key_put(nvme_keyring); |
| 170 | + return err; |
| 171 | + } |
| 172 | + return 0; |
| 173 | +} |
| 174 | +EXPORT_SYMBOL_GPL(nvme_keyring_init); |
| 175 | + |
| 176 | +void nvme_keyring_exit(void) |
| 177 | +{ |
| 178 | + unregister_key_type(&nvme_tls_psk_key_type); |
| 179 | + key_revoke(nvme_keyring); |
| 180 | + key_put(nvme_keyring); |
| 181 | +} |
| 182 | +EXPORT_SYMBOL_GPL(nvme_keyring_exit); |
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