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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2020 Hannes Reinecke, SUSE Linux
4 */
5
6#include <linux/module.h>
7#include <linux/crc32.h>
8#include <linux/base64.h>
9#include <linux/prandom.h>
10#include <linux/scatterlist.h>
11#include <linux/unaligned.h>
12#include <crypto/hash.h>
13#include <crypto/dh.h>
14#include <crypto/hkdf.h>
15#include <linux/nvme.h>
16#include <linux/nvme-auth.h>
17
18#define HKDF_MAX_HASHLEN 64
19
20static u32 nvme_dhchap_seqnum;
21static DEFINE_MUTEX(nvme_dhchap_mutex);
22
23u32 nvme_auth_get_seqnum(void)
24{
25 u32 seqnum;
26
27 mutex_lock(&nvme_dhchap_mutex);
28 if (!nvme_dhchap_seqnum)
29 nvme_dhchap_seqnum = get_random_u32();
30 else {
31 nvme_dhchap_seqnum++;
32 if (!nvme_dhchap_seqnum)
33 nvme_dhchap_seqnum++;
34 }
35 seqnum = nvme_dhchap_seqnum;
36 mutex_unlock(lock: &nvme_dhchap_mutex);
37 return seqnum;
38}
39EXPORT_SYMBOL_GPL(nvme_auth_get_seqnum);
40
41static struct nvme_auth_dhgroup_map {
42 const char name[16];
43 const char kpp[16];
44} dhgroup_map[] = {
45 [NVME_AUTH_DHGROUP_NULL] = {
46 .name = "null", .kpp = "null" },
47 [NVME_AUTH_DHGROUP_2048] = {
48 .name = "ffdhe2048", .kpp = "ffdhe2048(dh)" },
49 [NVME_AUTH_DHGROUP_3072] = {
50 .name = "ffdhe3072", .kpp = "ffdhe3072(dh)" },
51 [NVME_AUTH_DHGROUP_4096] = {
52 .name = "ffdhe4096", .kpp = "ffdhe4096(dh)" },
53 [NVME_AUTH_DHGROUP_6144] = {
54 .name = "ffdhe6144", .kpp = "ffdhe6144(dh)" },
55 [NVME_AUTH_DHGROUP_8192] = {
56 .name = "ffdhe8192", .kpp = "ffdhe8192(dh)" },
57};
58
59const char *nvme_auth_dhgroup_name(u8 dhgroup_id)
60{
61 if (dhgroup_id >= ARRAY_SIZE(dhgroup_map))
62 return NULL;
63 return dhgroup_map[dhgroup_id].name;
64}
65EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_name);
66
67const char *nvme_auth_dhgroup_kpp(u8 dhgroup_id)
68{
69 if (dhgroup_id >= ARRAY_SIZE(dhgroup_map))
70 return NULL;
71 return dhgroup_map[dhgroup_id].kpp;
72}
73EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_kpp);
74
75u8 nvme_auth_dhgroup_id(const char *dhgroup_name)
76{
77 int i;
78
79 if (!dhgroup_name || !strlen(dhgroup_name))
80 return NVME_AUTH_DHGROUP_INVALID;
81 for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
82 if (!strlen(dhgroup_map[i].name))
83 continue;
84 if (!strncmp(dhgroup_map[i].name, dhgroup_name,
85 strlen(dhgroup_map[i].name)))
86 return i;
87 }
88 return NVME_AUTH_DHGROUP_INVALID;
89}
90EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_id);
91
92static struct nvme_dhchap_hash_map {
93 int len;
94 const char hmac[15];
95 const char digest[8];
96} hash_map[] = {
97 [NVME_AUTH_HASH_SHA256] = {
98 .len = 32,
99 .hmac = "hmac(sha256)",
100 .digest = "sha256",
101 },
102 [NVME_AUTH_HASH_SHA384] = {
103 .len = 48,
104 .hmac = "hmac(sha384)",
105 .digest = "sha384",
106 },
107 [NVME_AUTH_HASH_SHA512] = {
108 .len = 64,
109 .hmac = "hmac(sha512)",
110 .digest = "sha512",
111 },
112};
113
114const char *nvme_auth_hmac_name(u8 hmac_id)
115{
116 if (hmac_id >= ARRAY_SIZE(hash_map))
117 return NULL;
118 return hash_map[hmac_id].hmac;
119}
120EXPORT_SYMBOL_GPL(nvme_auth_hmac_name);
121
122const char *nvme_auth_digest_name(u8 hmac_id)
123{
124 if (hmac_id >= ARRAY_SIZE(hash_map))
125 return NULL;
126 return hash_map[hmac_id].digest;
127}
128EXPORT_SYMBOL_GPL(nvme_auth_digest_name);
129
130u8 nvme_auth_hmac_id(const char *hmac_name)
131{
132 int i;
133
134 if (!hmac_name || !strlen(hmac_name))
135 return NVME_AUTH_HASH_INVALID;
136
137 for (i = 0; i < ARRAY_SIZE(hash_map); i++) {
138 if (!strlen(hash_map[i].hmac))
139 continue;
140 if (!strncmp(hash_map[i].hmac, hmac_name,
141 strlen(hash_map[i].hmac)))
142 return i;
143 }
144 return NVME_AUTH_HASH_INVALID;
145}
146EXPORT_SYMBOL_GPL(nvme_auth_hmac_id);
147
148size_t nvme_auth_hmac_hash_len(u8 hmac_id)
149{
150 if (hmac_id >= ARRAY_SIZE(hash_map))
151 return 0;
152 return hash_map[hmac_id].len;
153}
154EXPORT_SYMBOL_GPL(nvme_auth_hmac_hash_len);
155
156u32 nvme_auth_key_struct_size(u32 key_len)
157{
158 struct nvme_dhchap_key key;
159
160 return struct_size(&key, key, key_len);
161}
162EXPORT_SYMBOL_GPL(nvme_auth_key_struct_size);
163
164struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
165 u8 key_hash)
166{
167 struct nvme_dhchap_key *key;
168 unsigned char *p;
169 u32 crc;
170 int ret, key_len;
171 size_t allocated_len = strlen(secret);
172
173 /* Secret might be affixed with a ':' */
174 p = strrchr(secret, ':');
175 if (p)
176 allocated_len = p - secret;
177 key = nvme_auth_alloc_key(len: allocated_len, hash: 0);
178 if (!key)
179 return ERR_PTR(error: -ENOMEM);
180
181 key_len = base64_decode(src: secret, len: allocated_len, dst: key->key, padding: true, variant: BASE64_STD);
182 if (key_len < 0) {
183 pr_debug("base64 key decoding error %d\n",
184 key_len);
185 ret = key_len;
186 goto out_free_secret;
187 }
188
189 if (key_len != 36 && key_len != 52 &&
190 key_len != 68) {
191 pr_err("Invalid key len %d\n", key_len);
192 ret = -EINVAL;
193 goto out_free_secret;
194 }
195
196 /* The last four bytes is the CRC in little-endian format */
197 key_len -= 4;
198 /*
199 * The linux implementation doesn't do pre- and post-increments,
200 * so we have to do it manually.
201 */
202 crc = ~crc32(crc: ~0, p: key->key, len: key_len);
203
204 if (get_unaligned_le32(p: key->key + key_len) != crc) {
205 pr_err("key crc mismatch (key %08x, crc %08x)\n",
206 get_unaligned_le32(key->key + key_len), crc);
207 ret = -EKEYREJECTED;
208 goto out_free_secret;
209 }
210 key->len = key_len;
211 key->hash = key_hash;
212 return key;
213out_free_secret:
214 nvme_auth_free_key(key);
215 return ERR_PTR(error: ret);
216}
217EXPORT_SYMBOL_GPL(nvme_auth_extract_key);
218
219struct nvme_dhchap_key *nvme_auth_alloc_key(u32 len, u8 hash)
220{
221 u32 num_bytes = nvme_auth_key_struct_size(len);
222 struct nvme_dhchap_key *key = kzalloc(num_bytes, GFP_KERNEL);
223
224 if (key) {
225 key->len = len;
226 key->hash = hash;
227 }
228 return key;
229}
230EXPORT_SYMBOL_GPL(nvme_auth_alloc_key);
231
232void nvme_auth_free_key(struct nvme_dhchap_key *key)
233{
234 if (!key)
235 return;
236 kfree_sensitive(objp: key);
237}
238EXPORT_SYMBOL_GPL(nvme_auth_free_key);
239
240struct nvme_dhchap_key *nvme_auth_transform_key(
241 struct nvme_dhchap_key *key, char *nqn)
242{
243 const char *hmac_name;
244 struct crypto_shash *key_tfm;
245 SHASH_DESC_ON_STACK(shash, key_tfm);
246 struct nvme_dhchap_key *transformed_key;
247 int ret, key_len;
248
249 if (!key) {
250 pr_warn("No key specified\n");
251 return ERR_PTR(error: -ENOKEY);
252 }
253 if (key->hash == 0) {
254 key_len = nvme_auth_key_struct_size(key->len);
255 transformed_key = kmemdup(key, key_len, GFP_KERNEL);
256 if (!transformed_key)
257 return ERR_PTR(error: -ENOMEM);
258 return transformed_key;
259 }
260 hmac_name = nvme_auth_hmac_name(key->hash);
261 if (!hmac_name) {
262 pr_warn("Invalid key hash id %d\n", key->hash);
263 return ERR_PTR(error: -EINVAL);
264 }
265
266 key_tfm = crypto_alloc_shash(alg_name: hmac_name, type: 0, mask: 0);
267 if (IS_ERR(ptr: key_tfm))
268 return ERR_CAST(ptr: key_tfm);
269
270 key_len = crypto_shash_digestsize(tfm: key_tfm);
271 transformed_key = nvme_auth_alloc_key(key_len, key->hash);
272 if (!transformed_key) {
273 ret = -ENOMEM;
274 goto out_free_key;
275 }
276
277 shash->tfm = key_tfm;
278 ret = crypto_shash_setkey(tfm: key_tfm, key: key->key, keylen: key->len);
279 if (ret < 0)
280 goto out_free_transformed_key;
281 ret = crypto_shash_init(desc: shash);
282 if (ret < 0)
283 goto out_free_transformed_key;
284 ret = crypto_shash_update(desc: shash, data: nqn, strlen(nqn));
285 if (ret < 0)
286 goto out_free_transformed_key;
287 ret = crypto_shash_update(desc: shash, data: "NVMe-over-Fabrics", len: 17);
288 if (ret < 0)
289 goto out_free_transformed_key;
290 ret = crypto_shash_final(desc: shash, out: transformed_key->key);
291 if (ret < 0)
292 goto out_free_transformed_key;
293
294 crypto_free_shash(tfm: key_tfm);
295
296 return transformed_key;
297
298out_free_transformed_key:
299 nvme_auth_free_key(transformed_key);
300out_free_key:
301 crypto_free_shash(tfm: key_tfm);
302
303 return ERR_PTR(error: ret);
304}
305EXPORT_SYMBOL_GPL(nvme_auth_transform_key);
306
307static int nvme_auth_hash_skey(int hmac_id, u8 *skey, size_t skey_len, u8 *hkey)
308{
309 const char *digest_name;
310 struct crypto_shash *tfm;
311 int ret;
312
313 digest_name = nvme_auth_digest_name(hmac_id);
314 if (!digest_name) {
315 pr_debug("%s: failed to get digest for %d\n", __func__,
316 hmac_id);
317 return -EINVAL;
318 }
319 tfm = crypto_alloc_shash(alg_name: digest_name, type: 0, mask: 0);
320 if (IS_ERR(ptr: tfm))
321 return -ENOMEM;
322
323 ret = crypto_shash_tfm_digest(tfm, data: skey, len: skey_len, out: hkey);
324 if (ret < 0)
325 pr_debug("%s: Failed to hash digest len %zu\n", __func__,
326 skey_len);
327
328 crypto_free_shash(tfm);
329 return ret;
330}
331
332int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len,
333 u8 *challenge, u8 *aug, size_t hlen)
334{
335 struct crypto_shash *tfm;
336 u8 *hashed_key;
337 const char *hmac_name;
338 int ret;
339
340 hashed_key = kmalloc(hlen, GFP_KERNEL);
341 if (!hashed_key)
342 return -ENOMEM;
343
344 ret = nvme_auth_hash_skey(hmac_id, skey,
345 skey_len, hkey: hashed_key);
346 if (ret < 0)
347 goto out_free_key;
348
349 hmac_name = nvme_auth_hmac_name(hmac_id);
350 if (!hmac_name) {
351 pr_warn("%s: invalid hash algorithm %d\n",
352 __func__, hmac_id);
353 ret = -EINVAL;
354 goto out_free_key;
355 }
356
357 tfm = crypto_alloc_shash(alg_name: hmac_name, type: 0, mask: 0);
358 if (IS_ERR(ptr: tfm)) {
359 ret = PTR_ERR(ptr: tfm);
360 goto out_free_key;
361 }
362
363 ret = crypto_shash_setkey(tfm, key: hashed_key, keylen: hlen);
364 if (ret)
365 goto out_free_hash;
366
367 ret = crypto_shash_tfm_digest(tfm, data: challenge, len: hlen, out: aug);
368out_free_hash:
369 crypto_free_shash(tfm);
370out_free_key:
371 kfree_sensitive(objp: hashed_key);
372 return ret;
373}
374EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge);
375
376int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, u8 dh_gid)
377{
378 int ret;
379
380 ret = crypto_kpp_set_secret(tfm: dh_tfm, NULL, len: 0);
381 if (ret)
382 pr_debug("failed to set private key, error %d\n", ret);
383
384 return ret;
385}
386EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey);
387
388int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm,
389 u8 *host_key, size_t host_key_len)
390{
391 struct kpp_request *req;
392 struct crypto_wait wait;
393 struct scatterlist dst;
394 int ret;
395
396 req = kpp_request_alloc(tfm: dh_tfm, GFP_KERNEL);
397 if (!req)
398 return -ENOMEM;
399
400 crypto_init_wait(wait: &wait);
401 kpp_request_set_input(req, NULL, input_len: 0);
402 sg_init_one(&dst, host_key, host_key_len);
403 kpp_request_set_output(req, output: &dst, output_len: host_key_len);
404 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
405 cmpl: crypto_req_done, data: &wait);
406
407 ret = crypto_wait_req(err: crypto_kpp_generate_public_key(req), wait: &wait);
408 kpp_request_free(req);
409 return ret;
410}
411EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey);
412
413int nvme_auth_gen_shared_secret(struct crypto_kpp *dh_tfm,
414 u8 *ctrl_key, size_t ctrl_key_len,
415 u8 *sess_key, size_t sess_key_len)
416{
417 struct kpp_request *req;
418 struct crypto_wait wait;
419 struct scatterlist src, dst;
420 int ret;
421
422 req = kpp_request_alloc(tfm: dh_tfm, GFP_KERNEL);
423 if (!req)
424 return -ENOMEM;
425
426 crypto_init_wait(wait: &wait);
427 sg_init_one(&src, ctrl_key, ctrl_key_len);
428 kpp_request_set_input(req, input: &src, input_len: ctrl_key_len);
429 sg_init_one(&dst, sess_key, sess_key_len);
430 kpp_request_set_output(req, output: &dst, output_len: sess_key_len);
431 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
432 cmpl: crypto_req_done, data: &wait);
433
434 ret = crypto_wait_req(err: crypto_kpp_compute_shared_secret(req), wait: &wait);
435
436 kpp_request_free(req);
437 return ret;
438}
439EXPORT_SYMBOL_GPL(nvme_auth_gen_shared_secret);
440
441int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key)
442{
443 struct nvme_dhchap_key *key;
444 u8 key_hash;
445
446 if (!secret) {
447 *ret_key = NULL;
448 return 0;
449 }
450
451 if (sscanf(secret, "DHHC-1:%hhd:%*s:", &key_hash) != 1)
452 return -EINVAL;
453
454 /* Pass in the secret without the 'DHHC-1:XX:' prefix */
455 key = nvme_auth_extract_key(secret + 10, key_hash);
456 if (IS_ERR(ptr: key)) {
457 *ret_key = NULL;
458 return PTR_ERR(ptr: key);
459 }
460
461 *ret_key = key;
462 return 0;
463}
464EXPORT_SYMBOL_GPL(nvme_auth_generate_key);
465
466/**
467 * nvme_auth_generate_psk - Generate a PSK for TLS
468 * @hmac_id: Hash function identifier
469 * @skey: Session key
470 * @skey_len: Length of @skey
471 * @c1: Value of challenge C1
472 * @c2: Value of challenge C2
473 * @hash_len: Hash length of the hash algorithm
474 * @ret_psk: Pointer to the resulting generated PSK
475 * @ret_len: length of @ret_psk
476 *
477 * Generate a PSK for TLS as specified in NVMe base specification, section
478 * 8.13.5.9: Generated PSK for TLS
479 *
480 * The generated PSK for TLS shall be computed applying the HMAC function
481 * using the hash function H( ) selected by the HashID parameter in the
482 * DH-HMAC-CHAP_Challenge message with the session key KS as key to the
483 * concatenation of the two challenges C1 and C2 (i.e., generated
484 * PSK = HMAC(KS, C1 || C2)).
485 *
486 * Returns 0 on success with a valid generated PSK pointer in @ret_psk and
487 * the length of @ret_psk in @ret_len, or a negative error number otherwise.
488 */
489int nvme_auth_generate_psk(u8 hmac_id, u8 *skey, size_t skey_len,
490 u8 *c1, u8 *c2, size_t hash_len, u8 **ret_psk, size_t *ret_len)
491{
492 struct crypto_shash *tfm;
493 SHASH_DESC_ON_STACK(shash, tfm);
494 u8 *psk;
495 const char *hmac_name;
496 int ret, psk_len;
497
498 if (!c1 || !c2)
499 return -EINVAL;
500
501 hmac_name = nvme_auth_hmac_name(hmac_id);
502 if (!hmac_name) {
503 pr_warn("%s: invalid hash algorithm %d\n",
504 __func__, hmac_id);
505 return -EINVAL;
506 }
507
508 tfm = crypto_alloc_shash(alg_name: hmac_name, type: 0, mask: 0);
509 if (IS_ERR(ptr: tfm))
510 return PTR_ERR(ptr: tfm);
511
512 psk_len = crypto_shash_digestsize(tfm);
513 psk = kzalloc(psk_len, GFP_KERNEL);
514 if (!psk) {
515 ret = -ENOMEM;
516 goto out_free_tfm;
517 }
518
519 shash->tfm = tfm;
520 ret = crypto_shash_setkey(tfm, key: skey, keylen: skey_len);
521 if (ret)
522 goto out_free_psk;
523
524 ret = crypto_shash_init(desc: shash);
525 if (ret)
526 goto out_free_psk;
527
528 ret = crypto_shash_update(desc: shash, data: c1, len: hash_len);
529 if (ret)
530 goto out_free_psk;
531
532 ret = crypto_shash_update(desc: shash, data: c2, len: hash_len);
533 if (ret)
534 goto out_free_psk;
535
536 ret = crypto_shash_final(desc: shash, out: psk);
537 if (!ret) {
538 *ret_psk = psk;
539 *ret_len = psk_len;
540 }
541
542out_free_psk:
543 if (ret)
544 kfree_sensitive(objp: psk);
545out_free_tfm:
546 crypto_free_shash(tfm);
547
548 return ret;
549}
550EXPORT_SYMBOL_GPL(nvme_auth_generate_psk);
551
552/**
553 * nvme_auth_generate_digest - Generate TLS PSK digest
554 * @hmac_id: Hash function identifier
555 * @psk: Generated input PSK
556 * @psk_len: Length of @psk
557 * @subsysnqn: NQN of the subsystem
558 * @hostnqn: NQN of the host
559 * @ret_digest: Pointer to the returned digest
560 *
561 * Generate a TLS PSK digest as specified in TP8018 Section 3.6.1.3:
562 * TLS PSK and PSK identity Derivation
563 *
564 * The PSK digest shall be computed by encoding in Base64 (refer to RFC
565 * 4648) the result of the application of the HMAC function using the hash
566 * function specified in item 4 above (ie the hash function of the cipher
567 * suite associated with the PSK identity) with the PSK as HMAC key to the
568 * concatenation of:
569 * - the NQN of the host (i.e., NQNh) not including the null terminator;
570 * - a space character;
571 * - the NQN of the NVM subsystem (i.e., NQNc) not including the null
572 * terminator;
573 * - a space character; and
574 * - the seventeen ASCII characters "NVMe-over-Fabrics"
575 * (i.e., <PSK digest> = Base64(HMAC(PSK, NQNh || " " || NQNc || " " ||
576 * "NVMe-over-Fabrics"))).
577 * The length of the PSK digest depends on the hash function used to compute
578 * it as follows:
579 * - If the SHA-256 hash function is used, the resulting PSK digest is 44
580 * characters long; or
581 * - If the SHA-384 hash function is used, the resulting PSK digest is 64
582 * characters long.
583 *
584 * Returns 0 on success with a valid digest pointer in @ret_digest, or a
585 * negative error number on failure.
586 */
587int nvme_auth_generate_digest(u8 hmac_id, u8 *psk, size_t psk_len,
588 char *subsysnqn, char *hostnqn, u8 **ret_digest)
589{
590 struct crypto_shash *tfm;
591 SHASH_DESC_ON_STACK(shash, tfm);
592 u8 *digest, *enc;
593 const char *hmac_name;
594 size_t digest_len, hmac_len;
595 int ret;
596
597 if (WARN_ON(!subsysnqn || !hostnqn))
598 return -EINVAL;
599
600 hmac_name = nvme_auth_hmac_name(hmac_id);
601 if (!hmac_name) {
602 pr_warn("%s: invalid hash algorithm %d\n",
603 __func__, hmac_id);
604 return -EINVAL;
605 }
606
607 switch (nvme_auth_hmac_hash_len(hmac_id)) {
608 case 32:
609 hmac_len = 44;
610 break;
611 case 48:
612 hmac_len = 64;
613 break;
614 default:
615 pr_warn("%s: invalid hash algorithm '%s'\n",
616 __func__, hmac_name);
617 return -EINVAL;
618 }
619
620 enc = kzalloc(hmac_len + 1, GFP_KERNEL);
621 if (!enc)
622 return -ENOMEM;
623
624 tfm = crypto_alloc_shash(alg_name: hmac_name, type: 0, mask: 0);
625 if (IS_ERR(ptr: tfm)) {
626 ret = PTR_ERR(ptr: tfm);
627 goto out_free_enc;
628 }
629
630 digest_len = crypto_shash_digestsize(tfm);
631 digest = kzalloc(digest_len, GFP_KERNEL);
632 if (!digest) {
633 ret = -ENOMEM;
634 goto out_free_tfm;
635 }
636
637 shash->tfm = tfm;
638 ret = crypto_shash_setkey(tfm, key: psk, keylen: psk_len);
639 if (ret)
640 goto out_free_digest;
641
642 ret = crypto_shash_init(desc: shash);
643 if (ret)
644 goto out_free_digest;
645
646 ret = crypto_shash_update(desc: shash, data: hostnqn, strlen(hostnqn));
647 if (ret)
648 goto out_free_digest;
649
650 ret = crypto_shash_update(desc: shash, data: " ", len: 1);
651 if (ret)
652 goto out_free_digest;
653
654 ret = crypto_shash_update(desc: shash, data: subsysnqn, strlen(subsysnqn));
655 if (ret)
656 goto out_free_digest;
657
658 ret = crypto_shash_update(desc: shash, data: " NVMe-over-Fabrics", len: 18);
659 if (ret)
660 goto out_free_digest;
661
662 ret = crypto_shash_final(desc: shash, out: digest);
663 if (ret)
664 goto out_free_digest;
665
666 ret = base64_encode(src: digest, len: digest_len, dst: enc, padding: true, variant: BASE64_STD);
667 if (ret < hmac_len) {
668 ret = -ENOKEY;
669 goto out_free_digest;
670 }
671 *ret_digest = enc;
672 ret = 0;
673
674out_free_digest:
675 kfree_sensitive(objp: digest);
676out_free_tfm:
677 crypto_free_shash(tfm);
678out_free_enc:
679 if (ret)
680 kfree_sensitive(objp: enc);
681
682 return ret;
683}
684EXPORT_SYMBOL_GPL(nvme_auth_generate_digest);
685
686/**
687 * hkdf_expand_label - HKDF-Expand-Label (RFC 8846 section 7.1)
688 * @hmac_tfm: hash context keyed with pseudorandom key
689 * @label: ASCII label without "tls13 " prefix
690 * @labellen: length of @label
691 * @context: context bytes
692 * @contextlen: length of @context
693 * @okm: output keying material
694 * @okmlen: length of @okm
695 *
696 * Build the TLS 1.3 HkdfLabel structure and invoke hkdf_expand().
697 *
698 * Returns 0 on success with output keying material stored in @okm,
699 * or a negative errno value otherwise.
700 */
701static int hkdf_expand_label(struct crypto_shash *hmac_tfm,
702 const u8 *label, unsigned int labellen,
703 const u8 *context, unsigned int contextlen,
704 u8 *okm, unsigned int okmlen)
705{
706 int err;
707 u8 *info;
708 unsigned int infolen;
709 const char *tls13_prefix = "tls13 ";
710 unsigned int prefixlen = strlen(tls13_prefix);
711
712 if (WARN_ON(labellen > (255 - prefixlen)))
713 return -EINVAL;
714 if (WARN_ON(contextlen > 255))
715 return -EINVAL;
716
717 infolen = 2 + (1 + prefixlen + labellen) + (1 + contextlen);
718 info = kzalloc(infolen, GFP_KERNEL);
719 if (!info)
720 return -ENOMEM;
721
722 /* HkdfLabel.Length */
723 put_unaligned_be16(val: okmlen, p: info);
724
725 /* HkdfLabel.Label */
726 info[2] = prefixlen + labellen;
727 memcpy(info + 3, tls13_prefix, prefixlen);
728 memcpy(info + 3 + prefixlen, label, labellen);
729
730 /* HkdfLabel.Context */
731 info[3 + prefixlen + labellen] = contextlen;
732 memcpy(info + 4 + prefixlen + labellen, context, contextlen);
733
734 err = hkdf_expand(hmac_tfm, info, infolen, okm, okmlen);
735 kfree_sensitive(objp: info);
736 return err;
737}
738
739/**
740 * nvme_auth_derive_tls_psk - Derive TLS PSK
741 * @hmac_id: Hash function identifier
742 * @psk: generated input PSK
743 * @psk_len: size of @psk
744 * @psk_digest: TLS PSK digest
745 * @ret_psk: Pointer to the resulting TLS PSK
746 *
747 * Derive a TLS PSK as specified in TP8018 Section 3.6.1.3:
748 * TLS PSK and PSK identity Derivation
749 *
750 * The TLS PSK shall be derived as follows from an input PSK
751 * (i.e., either a retained PSK or a generated PSK) and a PSK
752 * identity using the HKDF-Extract and HKDF-Expand-Label operations
753 * (refer to RFC 5869 and RFC 8446) where the hash function is the
754 * one specified by the hash specifier of the PSK identity:
755 * 1. PRK = HKDF-Extract(0, Input PSK); and
756 * 2. TLS PSK = HKDF-Expand-Label(PRK, "nvme-tls-psk", PskIdentityContext, L),
757 * where PskIdentityContext is the hash identifier indicated in
758 * the PSK identity concatenated to a space character and to the
759 * Base64 PSK digest (i.e., "<hash> <PSK digest>") and L is the
760 * output size in bytes of the hash function (i.e., 32 for SHA-256
761 * and 48 for SHA-384).
762 *
763 * Returns 0 on success with a valid psk pointer in @ret_psk or a negative
764 * error number otherwise.
765 */
766int nvme_auth_derive_tls_psk(int hmac_id, u8 *psk, size_t psk_len,
767 u8 *psk_digest, u8 **ret_psk)
768{
769 struct crypto_shash *hmac_tfm;
770 const char *hmac_name;
771 const char *label = "nvme-tls-psk";
772 static const char default_salt[HKDF_MAX_HASHLEN];
773 size_t prk_len;
774 const char *ctx;
775 unsigned char *prk, *tls_key;
776 int ret;
777
778 hmac_name = nvme_auth_hmac_name(hmac_id);
779 if (!hmac_name) {
780 pr_warn("%s: invalid hash algorithm %d\n",
781 __func__, hmac_id);
782 return -EINVAL;
783 }
784 if (hmac_id == NVME_AUTH_HASH_SHA512) {
785 pr_warn("%s: unsupported hash algorithm %s\n",
786 __func__, hmac_name);
787 return -EINVAL;
788 }
789
790 hmac_tfm = crypto_alloc_shash(alg_name: hmac_name, type: 0, mask: 0);
791 if (IS_ERR(ptr: hmac_tfm))
792 return PTR_ERR(ptr: hmac_tfm);
793
794 prk_len = crypto_shash_digestsize(tfm: hmac_tfm);
795 prk = kzalloc(prk_len, GFP_KERNEL);
796 if (!prk) {
797 ret = -ENOMEM;
798 goto out_free_shash;
799 }
800
801 if (WARN_ON(prk_len > HKDF_MAX_HASHLEN)) {
802 ret = -EINVAL;
803 goto out_free_prk;
804 }
805 ret = hkdf_extract(hmac_tfm, ikm: psk, ikmlen: psk_len,
806 salt: default_salt, saltlen: prk_len, prk);
807 if (ret)
808 goto out_free_prk;
809
810 ret = crypto_shash_setkey(tfm: hmac_tfm, key: prk, keylen: prk_len);
811 if (ret)
812 goto out_free_prk;
813
814 ctx = kasprintf(GFP_KERNEL, fmt: "%02d %s", hmac_id, psk_digest);
815 if (!ctx) {
816 ret = -ENOMEM;
817 goto out_free_prk;
818 }
819
820 tls_key = kzalloc(psk_len, GFP_KERNEL);
821 if (!tls_key) {
822 ret = -ENOMEM;
823 goto out_free_ctx;
824 }
825 ret = hkdf_expand_label(hmac_tfm,
826 label, strlen(label),
827 context: ctx, strlen(ctx),
828 okm: tls_key, okmlen: psk_len);
829 if (ret) {
830 kfree(objp: tls_key);
831 goto out_free_ctx;
832 }
833 *ret_psk = tls_key;
834
835out_free_ctx:
836 kfree(objp: ctx);
837out_free_prk:
838 kfree(objp: prk);
839out_free_shash:
840 crypto_free_shash(tfm: hmac_tfm);
841
842 return ret;
843}
844EXPORT_SYMBOL_GPL(nvme_auth_derive_tls_psk);
845
846MODULE_DESCRIPTION("NVMe Authentication framework");
847MODULE_LICENSE("GPL v2");
848

source code of linux/drivers/nvme/common/auth.c