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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-type.h>
9#include <keys/user-type.h>
10#include <linux/nvme.h>
11#include <linux/nvme-tcp.h>
12#include <linux/nvme-keyring.h>
13
14static struct key *nvme_keyring;
15
16key_serial_t nvme_keyring_id(void)
17{
18 return nvme_keyring->serial;
19}
20EXPORT_SYMBOL_GPL(nvme_keyring_id);
21
22static bool nvme_tls_psk_revoked(struct key *psk)
23{
24 return test_bit(KEY_FLAG_REVOKED, &psk->flags) ||
25 test_bit(KEY_FLAG_INVALIDATED, &psk->flags);
26}
27
28struct key *nvme_tls_key_lookup(key_serial_t key_id)
29{
30 struct key *key = key_lookup(key_id);
31
32 if (IS_ERR(key)) {
33 pr_err("key id %08x not found\n", key_id);
34 return key;
35 }
36 if (nvme_tls_psk_revoked(key)) {
37 pr_err("key id %08x revoked\n", key_id);
38 return ERR_PTR(-EKEYREVOKED);
39 }
40 return key;
41}
42EXPORT_SYMBOL_GPL(nvme_tls_key_lookup);
43
44static void nvme_tls_psk_describe(const struct key *key, struct seq_file *m)
45{
46 seq_puts(m, key->description);
47 seq_printf(m, ": %u", key->datalen);
48}
49
50static bool nvme_tls_psk_match(const struct key *key,
51 const struct key_match_data *match_data)
52{
53 const char *match_id;
54 size_t match_len;
55
56 if (!key->description) {
57 pr_debug("%s: no key description\n", __func__);
58 return false;
59 }
60 if (!match_data->raw_data) {
61 pr_debug("%s: no match data\n", __func__);
62 return false;
63 }
64 match_id = match_data->raw_data;
65 match_len = strlen(match_id);
66 pr_debug("%s: match '%s' '%s' len %zd\n",
67 __func__, match_id, key->description, match_len);
68 return !memcmp(key->description, match_id, match_len);
69}
70
71static int nvme_tls_psk_match_preparse(struct key_match_data *match_data)
72{
73 match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
74 match_data->cmp = nvme_tls_psk_match;
75 return 0;
76}
77
78static struct key_type nvme_tls_psk_key_type = {
79 .name = "psk",
80 .flags = KEY_TYPE_NET_DOMAIN,
81 .preparse = user_preparse,
82 .free_preparse = user_free_preparse,
83 .match_preparse = nvme_tls_psk_match_preparse,
84 .instantiate = generic_key_instantiate,
85 .revoke = user_revoke,
86 .destroy = user_destroy,
87 .describe = nvme_tls_psk_describe,
88 .read = user_read,
89};
90
91static struct key *nvme_tls_psk_lookup(struct key *keyring,
92 const char *hostnqn, const char *subnqn,
93 u8 hmac, u8 psk_ver, bool generated)
94{
95 char *identity;
96 size_t identity_len = (NVMF_NQN_SIZE) * 2 + 11;
97 key_ref_t keyref;
98 key_serial_t keyring_id;
99
100 identity = kzalloc(identity_len, GFP_KERNEL);
101 if (!identity)
102 return ERR_PTR(-ENOMEM);
103
104 snprintf(identity, identity_len, "NVMe%u%c%02u %s %s",
105 psk_ver, generated ? 'G' : 'R', hmac, hostnqn, subnqn);
106
107 if (!keyring)
108 keyring = nvme_keyring;
109 keyring_id = key_serial(keyring);
110 pr_debug("keyring %x lookup tls psk '%s'\n",
111 keyring_id, identity);
112 keyref = keyring_search(make_key_ref(keyring, true),
113 &nvme_tls_psk_key_type,
114 identity, false);
115 if (IS_ERR(keyref)) {
116 pr_debug("lookup tls psk '%s' failed, error %ld\n",
117 identity, PTR_ERR(keyref));
118 kfree(identity);
119 return ERR_PTR(-ENOKEY);
120 }
121 kfree(identity);
122
123 return key_ref_to_ptr(keyref);
124}
125
126/**
127 * nvme_tls_psk_refresh - Refresh TLS PSK
128 * @keyring: Keyring holding the TLS PSK
129 * @hostnqn: Host NQN to use
130 * @subnqn: Subsystem NQN to use
131 * @hmac_id: Hash function identifier
132 * @data: TLS PSK key material
133 * @data_len: Length of @data
134 * @digest: TLS PSK digest
135 *
136 * Refresh a generated version 1 TLS PSK with the identity generated
137 * from @hmac_id, @hostnqn, @subnqn, and @digest in the keyring given
138 * by @keyring.
139 *
140 * Returns the updated key success or an error pointer otherwise.
141 */
142struct key *nvme_tls_psk_refresh(struct key *keyring,
143 const char *hostnqn, const char *subnqn, u8 hmac_id,
144 u8 *data, size_t data_len, const char *digest)
145{
146 key_perm_t keyperm =
147 KEY_POS_SEARCH | KEY_POS_VIEW | KEY_POS_READ |
148 KEY_POS_WRITE | KEY_POS_LINK | KEY_POS_SETATTR |
149 KEY_USR_SEARCH | KEY_USR_VIEW | KEY_USR_READ;
150 char *identity;
151 key_ref_t keyref;
152 key_serial_t keyring_id;
153 struct key *key;
154
155 if (!hostnqn || !subnqn || !data || !data_len)
156 return ERR_PTR(-EINVAL);
157
158 identity = kasprintf(GFP_KERNEL, "NVMe1G%02d %s %s %s",
159 hmac_id, hostnqn, subnqn, digest);
160 if (!identity)
161 return ERR_PTR(-ENOMEM);
162
163 if (!keyring)
164 keyring = nvme_keyring;
165 keyring_id = key_serial(keyring);
166 pr_debug("keyring %x refresh tls psk '%s'\n",
167 keyring_id, identity);
168 keyref = key_create_or_update(make_key_ref(keyring, true),
169 "psk", identity, data, data_len,
170 keyperm, KEY_ALLOC_NOT_IN_QUOTA |
171 KEY_ALLOC_BUILT_IN |
172 KEY_ALLOC_BYPASS_RESTRICTION);
173 if (IS_ERR(keyref)) {
174 pr_debug("refresh tls psk '%s' failed, error %ld\n",
175 identity, PTR_ERR(keyref));
176 kfree(identity);
177 return ERR_PTR(-ENOKEY);
178 }
179 kfree(identity);
180 /*
181 * Set the default timeout to 1 hour
182 * as suggested in TP8018.
183 */
184 key = key_ref_to_ptr(keyref);
185 key_set_timeout(key, 3600);
186 return key;
187}
188EXPORT_SYMBOL_GPL(nvme_tls_psk_refresh);
189
190/*
191 * NVMe PSK priority list
192 *
193 * 'Retained' PSKs (ie 'generated == false') should be preferred to 'generated'
194 * PSKs, PSKs with hash (psk_ver 1) should be preferred to PSKs without hash
195 * (psk_ver 0), and SHA-384 should be preferred to SHA-256.
196 */
197static struct nvme_tls_psk_priority_list {
198 bool generated;
199 u8 psk_ver;
200 enum nvme_tcp_tls_cipher cipher;
201} nvme_tls_psk_prio[] = {
202 { .generated = false,
203 .psk_ver = 1,
204 .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
205 { .generated = false,
206 .psk_ver = 1,
207 .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
208 { .generated = false,
209 .psk_ver = 0,
210 .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
211 { .generated = false,
212 .psk_ver = 0,
213 .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
214 { .generated = true,
215 .psk_ver = 1,
216 .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
217 { .generated = true,
218 .psk_ver = 1,
219 .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
220 { .generated = true,
221 .psk_ver = 0,
222 .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
223 { .generated = true,
224 .psk_ver = 0,
225 .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
226};
227
228/*
229 * nvme_tls_psk_default - Return the preferred PSK to use for TLS ClientHello
230 */
231key_serial_t nvme_tls_psk_default(struct key *keyring,
232 const char *hostnqn, const char *subnqn)
233{
234 struct key *tls_key;
235 key_serial_t tls_key_id;
236 int prio;
237
238 for (prio = 0; prio < ARRAY_SIZE(nvme_tls_psk_prio); prio++) {
239 bool generated = nvme_tls_psk_prio[prio].generated;
240 u8 ver = nvme_tls_psk_prio[prio].psk_ver;
241 enum nvme_tcp_tls_cipher cipher = nvme_tls_psk_prio[prio].cipher;
242
243 tls_key = nvme_tls_psk_lookup(keyring, hostnqn, subnqn,
244 cipher, ver, generated);
245 if (!IS_ERR(tls_key)) {
246 tls_key_id = tls_key->serial;
247 key_put(tls_key);
248 return tls_key_id;
249 }
250 }
251 return 0;
252}
253EXPORT_SYMBOL_GPL(nvme_tls_psk_default);
254
255static int __init nvme_keyring_init(void)
256{
257 int err;
258
259 nvme_keyring = keyring_alloc(".nvme",
260 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
261 current_cred(),
262 (KEY_POS_ALL & ~KEY_POS_SETATTR) |
263 (KEY_USR_ALL & ~KEY_USR_SETATTR),
264 KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
265 if (IS_ERR(nvme_keyring))
266 return PTR_ERR(nvme_keyring);
267
268 err = register_key_type(&nvme_tls_psk_key_type);
269 if (err) {
270 key_put(nvme_keyring);
271 return err;
272 }
273 return 0;
274}
275
276static void __exit nvme_keyring_exit(void)
277{
278 unregister_key_type(&nvme_tls_psk_key_type);
279 key_revoke(nvme_keyring);
280 key_put(nvme_keyring);
281}
282
283MODULE_LICENSE("GPL v2");
284MODULE_AUTHOR("Hannes Reinecke <[email protected]>");
285MODULE_DESCRIPTION("NVMe Keyring implementation");
286module_init(nvme_keyring_init);
287module_exit(nvme_keyring_exit);