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
20 static u32 nvme_dhchap_seqnum;
21 static DEFINE_MUTEX(nvme_dhchap_mutex);
22
nvme_auth_get_seqnum(void)23 u32 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(&nvme_dhchap_mutex);
37 return seqnum;
38 }
39 EXPORT_SYMBOL_GPL(nvme_auth_get_seqnum);
40
41 static 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
nvme_auth_dhgroup_name(u8 dhgroup_id)59 const 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 }
65 EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_name);
66
nvme_auth_dhgroup_kpp(u8 dhgroup_id)67 const 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 }
73 EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_kpp);
74
nvme_auth_dhgroup_id(const char * dhgroup_name)75 u8 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 }
90 EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_id);
91
92 static 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
nvme_auth_hmac_name(u8 hmac_id)114 const 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 }
120 EXPORT_SYMBOL_GPL(nvme_auth_hmac_name);
121
nvme_auth_digest_name(u8 hmac_id)122 const 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 }
128 EXPORT_SYMBOL_GPL(nvme_auth_digest_name);
129
nvme_auth_hmac_id(const char * hmac_name)130 u8 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 }
146 EXPORT_SYMBOL_GPL(nvme_auth_hmac_id);
147
nvme_auth_hmac_hash_len(u8 hmac_id)148 size_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 }
154 EXPORT_SYMBOL_GPL(nvme_auth_hmac_hash_len);
155
nvme_auth_key_struct_size(u32 key_len)156 u32 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 }
162 EXPORT_SYMBOL_GPL(nvme_auth_key_struct_size);
163
nvme_auth_extract_key(unsigned char * secret,u8 key_hash)164 struct 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(allocated_len, 0);
178 if (!key)
179 return ERR_PTR(-ENOMEM);
180
181 key_len = base64_decode(secret, allocated_len, key->key);
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(~0, key->key, key_len);
203
204 if (get_unaligned_le32(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;
213 out_free_secret:
214 nvme_auth_free_key(key);
215 return ERR_PTR(ret);
216 }
217 EXPORT_SYMBOL_GPL(nvme_auth_extract_key);
218
nvme_auth_alloc_key(u32 len,u8 hash)219 struct 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 }
230 EXPORT_SYMBOL_GPL(nvme_auth_alloc_key);
231
nvme_auth_free_key(struct nvme_dhchap_key * key)232 void nvme_auth_free_key(struct nvme_dhchap_key *key)
233 {
234 if (!key)
235 return;
236 kfree_sensitive(key);
237 }
238 EXPORT_SYMBOL_GPL(nvme_auth_free_key);
239
nvme_auth_transform_key(struct nvme_dhchap_key * key,char * nqn)240 struct 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(-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(-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(-EINVAL);
264 }
265
266 key_tfm = crypto_alloc_shash(hmac_name, 0, 0);
267 if (IS_ERR(key_tfm))
268 return ERR_CAST(key_tfm);
269
270 key_len = crypto_shash_digestsize(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(key_tfm, key->key, key->len);
279 if (ret < 0)
280 goto out_free_transformed_key;
281 ret = crypto_shash_init(shash);
282 if (ret < 0)
283 goto out_free_transformed_key;
284 ret = crypto_shash_update(shash, nqn, strlen(nqn));
285 if (ret < 0)
286 goto out_free_transformed_key;
287 ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17);
288 if (ret < 0)
289 goto out_free_transformed_key;
290 ret = crypto_shash_final(shash, transformed_key->key);
291 if (ret < 0)
292 goto out_free_transformed_key;
293
294 crypto_free_shash(key_tfm);
295
296 return transformed_key;
297
298 out_free_transformed_key:
299 nvme_auth_free_key(transformed_key);
300 out_free_key:
301 crypto_free_shash(key_tfm);
302
303 return ERR_PTR(ret);
304 }
305 EXPORT_SYMBOL_GPL(nvme_auth_transform_key);
306
nvme_auth_hash_skey(int hmac_id,u8 * skey,size_t skey_len,u8 * hkey)307 static 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(digest_name, 0, 0);
320 if (IS_ERR(tfm))
321 return -ENOMEM;
322
323 ret = crypto_shash_tfm_digest(tfm, skey, skey_len, 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
nvme_auth_augmented_challenge(u8 hmac_id,u8 * skey,size_t skey_len,u8 * challenge,u8 * aug,size_t hlen)332 int 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, 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(hmac_name, 0, 0);
358 if (IS_ERR(tfm)) {
359 ret = PTR_ERR(tfm);
360 goto out_free_key;
361 }
362
363 ret = crypto_shash_setkey(tfm, hashed_key, hlen);
364 if (ret)
365 goto out_free_hash;
366
367 ret = crypto_shash_tfm_digest(tfm, challenge, hlen, aug);
368 out_free_hash:
369 crypto_free_shash(tfm);
370 out_free_key:
371 kfree_sensitive(hashed_key);
372 return ret;
373 }
374 EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge);
375
nvme_auth_gen_privkey(struct crypto_kpp * dh_tfm,u8 dh_gid)376 int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, u8 dh_gid)
377 {
378 int ret;
379
380 ret = crypto_kpp_set_secret(dh_tfm, NULL, 0);
381 if (ret)
382 pr_debug("failed to set private key, error %d\n", ret);
383
384 return ret;
385 }
386 EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey);
387
nvme_auth_gen_pubkey(struct crypto_kpp * dh_tfm,u8 * host_key,size_t host_key_len)388 int 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(dh_tfm, GFP_KERNEL);
397 if (!req)
398 return -ENOMEM;
399
400 crypto_init_wait(&wait);
401 kpp_request_set_input(req, NULL, 0);
402 sg_init_one(&dst, host_key, host_key_len);
403 kpp_request_set_output(req, &dst, host_key_len);
404 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
405 crypto_req_done, &wait);
406
407 ret = crypto_wait_req(crypto_kpp_generate_public_key(req), &wait);
408 kpp_request_free(req);
409 return ret;
410 }
411 EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey);
412
nvme_auth_gen_shared_secret(struct crypto_kpp * dh_tfm,u8 * ctrl_key,size_t ctrl_key_len,u8 * sess_key,size_t sess_key_len)413 int 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(dh_tfm, GFP_KERNEL);
423 if (!req)
424 return -ENOMEM;
425
426 crypto_init_wait(&wait);
427 sg_init_one(&src, ctrl_key, ctrl_key_len);
428 kpp_request_set_input(req, &src, ctrl_key_len);
429 sg_init_one(&dst, sess_key, sess_key_len);
430 kpp_request_set_output(req, &dst, sess_key_len);
431 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
432 crypto_req_done, &wait);
433
434 ret = crypto_wait_req(crypto_kpp_compute_shared_secret(req), &wait);
435
436 kpp_request_free(req);
437 return ret;
438 }
439 EXPORT_SYMBOL_GPL(nvme_auth_gen_shared_secret);
440
nvme_auth_generate_key(u8 * secret,struct nvme_dhchap_key ** ret_key)441 int 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(key)) {
457 *ret_key = NULL;
458 return PTR_ERR(key);
459 }
460
461 *ret_key = key;
462 return 0;
463 }
464 EXPORT_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 */
nvme_auth_generate_psk(u8 hmac_id,u8 * skey,size_t skey_len,u8 * c1,u8 * c2,size_t hash_len,u8 ** ret_psk,size_t * ret_len)489 int 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(hmac_name, 0, 0);
509 if (IS_ERR(tfm))
510 return PTR_ERR(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, skey, skey_len);
521 if (ret)
522 goto out_free_psk;
523
524 ret = crypto_shash_init(shash);
525 if (ret)
526 goto out_free_psk;
527
528 ret = crypto_shash_update(shash, c1, hash_len);
529 if (ret)
530 goto out_free_psk;
531
532 ret = crypto_shash_update(shash, c2, hash_len);
533 if (ret)
534 goto out_free_psk;
535
536 ret = crypto_shash_final(shash, psk);
537 if (!ret) {
538 *ret_psk = psk;
539 *ret_len = psk_len;
540 }
541
542 out_free_psk:
543 if (ret)
544 kfree_sensitive(psk);
545 out_free_tfm:
546 crypto_free_shash(tfm);
547
548 return ret;
549 }
550 EXPORT_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 */
nvme_auth_generate_digest(u8 hmac_id,u8 * psk,size_t psk_len,char * subsysnqn,char * hostnqn,u8 ** ret_digest)587 int 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(hmac_name, 0, 0);
625 if (IS_ERR(tfm)) {
626 ret = PTR_ERR(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, psk, psk_len);
639 if (ret)
640 goto out_free_digest;
641
642 ret = crypto_shash_init(shash);
643 if (ret)
644 goto out_free_digest;
645
646 ret = crypto_shash_update(shash, hostnqn, strlen(hostnqn));
647 if (ret)
648 goto out_free_digest;
649
650 ret = crypto_shash_update(shash, " ", 1);
651 if (ret)
652 goto out_free_digest;
653
654 ret = crypto_shash_update(shash, subsysnqn, strlen(subsysnqn));
655 if (ret)
656 goto out_free_digest;
657
658 ret = crypto_shash_update(shash, " NVMe-over-Fabrics", 18);
659 if (ret)
660 goto out_free_digest;
661
662 ret = crypto_shash_final(shash, digest);
663 if (ret)
664 goto out_free_digest;
665
666 ret = base64_encode(digest, digest_len, enc);
667 if (ret < hmac_len) {
668 ret = -ENOKEY;
669 goto out_free_digest;
670 }
671 *ret_digest = enc;
672 ret = 0;
673
674 out_free_digest:
675 kfree_sensitive(digest);
676 out_free_tfm:
677 crypto_free_shash(tfm);
678 out_free_enc:
679 if (ret)
680 kfree_sensitive(enc);
681
682 return ret;
683 }
684 EXPORT_SYMBOL_GPL(nvme_auth_generate_digest);
685
686 /**
687 * nvme_auth_derive_tls_psk - Derive TLS PSK
688 * @hmac_id: Hash function identifier
689 * @psk: generated input PSK
690 * @psk_len: size of @psk
691 * @psk_digest: TLS PSK digest
692 * @ret_psk: Pointer to the resulting TLS PSK
693 *
694 * Derive a TLS PSK as specified in TP8018 Section 3.6.1.3:
695 * TLS PSK and PSK identity Derivation
696 *
697 * The TLS PSK shall be derived as follows from an input PSK
698 * (i.e., either a retained PSK or a generated PSK) and a PSK
699 * identity using the HKDF-Extract and HKDF-Expand-Label operations
700 * (refer to RFC 5869 and RFC 8446) where the hash function is the
701 * one specified by the hash specifier of the PSK identity:
702 * 1. PRK = HKDF-Extract(0, Input PSK); and
703 * 2. TLS PSK = HKDF-Expand-Label(PRK, "nvme-tls-psk", PskIdentityContext, L),
704 * where PskIdentityContext is the hash identifier indicated in
705 * the PSK identity concatenated to a space character and to the
706 * Base64 PSK digest (i.e., "<hash> <PSK digest>") and L is the
707 * output size in bytes of the hash function (i.e., 32 for SHA-256
708 * and 48 for SHA-384).
709 *
710 * Returns 0 on success with a valid psk pointer in @ret_psk or a negative
711 * error number otherwise.
712 */
nvme_auth_derive_tls_psk(int hmac_id,u8 * psk,size_t psk_len,u8 * psk_digest,u8 ** ret_psk)713 int nvme_auth_derive_tls_psk(int hmac_id, u8 *psk, size_t psk_len,
714 u8 *psk_digest, u8 **ret_psk)
715 {
716 struct crypto_shash *hmac_tfm;
717 const char *hmac_name;
718 const char *psk_prefix = "tls13 nvme-tls-psk";
719 static const char default_salt[HKDF_MAX_HASHLEN];
720 size_t info_len, prk_len;
721 char *info;
722 unsigned char *prk, *tls_key;
723 int ret;
724
725 hmac_name = nvme_auth_hmac_name(hmac_id);
726 if (!hmac_name) {
727 pr_warn("%s: invalid hash algorithm %d\n",
728 __func__, hmac_id);
729 return -EINVAL;
730 }
731 if (hmac_id == NVME_AUTH_HASH_SHA512) {
732 pr_warn("%s: unsupported hash algorithm %s\n",
733 __func__, hmac_name);
734 return -EINVAL;
735 }
736
737 hmac_tfm = crypto_alloc_shash(hmac_name, 0, 0);
738 if (IS_ERR(hmac_tfm))
739 return PTR_ERR(hmac_tfm);
740
741 prk_len = crypto_shash_digestsize(hmac_tfm);
742 prk = kzalloc(prk_len, GFP_KERNEL);
743 if (!prk) {
744 ret = -ENOMEM;
745 goto out_free_shash;
746 }
747
748 if (WARN_ON(prk_len > HKDF_MAX_HASHLEN)) {
749 ret = -EINVAL;
750 goto out_free_prk;
751 }
752 ret = hkdf_extract(hmac_tfm, psk, psk_len,
753 default_salt, prk_len, prk);
754 if (ret)
755 goto out_free_prk;
756
757 ret = crypto_shash_setkey(hmac_tfm, prk, prk_len);
758 if (ret)
759 goto out_free_prk;
760
761 /*
762 * 2 additional bytes for the length field from HDKF-Expand-Label,
763 * 2 additional bytes for the HMAC ID, and one byte for the space
764 * separator.
765 */
766 info_len = strlen(psk_digest) + strlen(psk_prefix) + 5;
767 info = kzalloc(info_len + 1, GFP_KERNEL);
768 if (!info) {
769 ret = -ENOMEM;
770 goto out_free_prk;
771 }
772
773 put_unaligned_be16(psk_len, info);
774 memcpy(info + 2, psk_prefix, strlen(psk_prefix));
775 sprintf(info + 2 + strlen(psk_prefix), "%02d %s", hmac_id, psk_digest);
776
777 tls_key = kzalloc(psk_len, GFP_KERNEL);
778 if (!tls_key) {
779 ret = -ENOMEM;
780 goto out_free_info;
781 }
782 ret = hkdf_expand(hmac_tfm, info, info_len, tls_key, psk_len);
783 if (ret) {
784 kfree(tls_key);
785 goto out_free_info;
786 }
787 *ret_psk = tls_key;
788
789 out_free_info:
790 kfree(info);
791 out_free_prk:
792 kfree(prk);
793 out_free_shash:
794 crypto_free_shash(hmac_tfm);
795
796 return ret;
797 }
798 EXPORT_SYMBOL_GPL(nvme_auth_derive_tls_psk);
799
800 MODULE_DESCRIPTION("NVMe Authentication framework");
801 MODULE_LICENSE("GPL v2");
802