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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * NVMe over Fabrics DH-HMAC-CHAP authentication.
4 * Copyright (c) 2020 Hannes Reinecke, SUSE Software Solutions.
5 * All rights reserved.
6 */
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/slab.h>
11#include <linux/err.h>
12#include <linux/crc32.h>
13#include <linux/base64.h>
14#include <linux/ctype.h>
15#include <linux/random.h>
16#include <linux/nvme-auth.h>
17#include <linux/nvme-keyring.h>
18#include <linux/unaligned.h>
19
20#include "nvmet.h"
21
22int nvmet_auth_set_key(struct nvmet_host *host, const char *secret,
23 bool set_ctrl)
24{
25 unsigned char key_hash;
26 char *dhchap_secret;
27
28 if (!strlen(secret)) {
29 if (set_ctrl) {
30 kfree(host->dhchap_ctrl_secret);
31 host->dhchap_ctrl_secret = NULL;
32 host->dhchap_ctrl_key_hash = 0;
33 } else {
34 kfree(host->dhchap_secret);
35 host->dhchap_secret = NULL;
36 host->dhchap_key_hash = 0;
37 }
38 return 0;
39 }
40 if (sscanf(secret, "DHHC-1:%hhd:%*s", &key_hash) != 1)
41 return -EINVAL;
42 if (key_hash > 3) {
43 pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
44 key_hash);
45 return -EINVAL;
46 }
47 dhchap_secret = kstrdup(secret, GFP_KERNEL);
48 if (!dhchap_secret)
49 return -ENOMEM;
50 down_write(&nvmet_config_sem);
51 if (set_ctrl) {
52 kfree(host->dhchap_ctrl_secret);
53 host->dhchap_ctrl_secret = strim(dhchap_secret);
54 host->dhchap_ctrl_key_hash = key_hash;
55 } else {
56 kfree(host->dhchap_secret);
57 host->dhchap_secret = strim(dhchap_secret);
58 host->dhchap_key_hash = key_hash;
59 }
60 up_write(&nvmet_config_sem);
61 return 0;
62}
63
64int nvmet_setup_dhgroup(struct nvmet_ctrl *ctrl, u8 dhgroup_id)
65{
66 const char *dhgroup_kpp;
67 int ret = 0;
68
69 pr_debug("%s: ctrl %d selecting dhgroup %d\n",
70 __func__, ctrl->cntlid, dhgroup_id);
71
72 if (ctrl->dh_tfm) {
73 if (ctrl->dh_gid == dhgroup_id) {
74 pr_debug("%s: ctrl %d reuse existing DH group %d\n",
75 __func__, ctrl->cntlid, dhgroup_id);
76 return 0;
77 }
78 crypto_free_kpp(ctrl->dh_tfm);
79 ctrl->dh_tfm = NULL;
80 ctrl->dh_gid = 0;
81 }
82
83 if (dhgroup_id == NVME_AUTH_DHGROUP_NULL)
84 return 0;
85
86 dhgroup_kpp = nvme_auth_dhgroup_kpp(dhgroup_id);
87 if (!dhgroup_kpp) {
88 pr_debug("%s: ctrl %d invalid DH group %d\n",
89 __func__, ctrl->cntlid, dhgroup_id);
90 return -EINVAL;
91 }
92 ctrl->dh_tfm = crypto_alloc_kpp(dhgroup_kpp, 0, 0);
93 if (IS_ERR(ctrl->dh_tfm)) {
94 pr_debug("%s: ctrl %d failed to setup DH group %d, err %ld\n",
95 __func__, ctrl->cntlid, dhgroup_id,
96 PTR_ERR(ctrl->dh_tfm));
97 ret = PTR_ERR(ctrl->dh_tfm);
98 ctrl->dh_tfm = NULL;
99 ctrl->dh_gid = 0;
100 } else {
101 ctrl->dh_gid = dhgroup_id;
102 pr_debug("%s: ctrl %d setup DH group %d\n",
103 __func__, ctrl->cntlid, ctrl->dh_gid);
104 ret = nvme_auth_gen_privkey(ctrl->dh_tfm, ctrl->dh_gid);
105 if (ret < 0) {
106 pr_debug("%s: ctrl %d failed to generate private key, err %d\n",
107 __func__, ctrl->cntlid, ret);
108 kfree_sensitive(ctrl->dh_key);
109 ctrl->dh_key = NULL;
110 return ret;
111 }
112 ctrl->dh_keysize = crypto_kpp_maxsize(ctrl->dh_tfm);
113 kfree_sensitive(ctrl->dh_key);
114 ctrl->dh_key = kzalloc(ctrl->dh_keysize, GFP_KERNEL);
115 if (!ctrl->dh_key) {
116 pr_warn("ctrl %d failed to allocate public key\n",
117 ctrl->cntlid);
118 return -ENOMEM;
119 }
120 ret = nvme_auth_gen_pubkey(ctrl->dh_tfm, ctrl->dh_key,
121 ctrl->dh_keysize);
122 if (ret < 0) {
123 pr_warn("ctrl %d failed to generate public key\n",
124 ctrl->cntlid);
125 kfree(ctrl->dh_key);
126 ctrl->dh_key = NULL;
127 }
128 }
129
130 return ret;
131}
132
133u8 nvmet_setup_auth(struct nvmet_ctrl *ctrl, struct nvmet_sq *sq, bool reset)
134{
135 int ret = 0;
136 struct nvmet_host_link *p;
137 struct nvmet_host *host = NULL;
138
139 down_read(&nvmet_config_sem);
140 if (nvmet_is_disc_subsys(ctrl->subsys))
141 goto out_unlock;
142
143 if (ctrl->subsys->allow_any_host)
144 goto out_unlock;
145
146 list_for_each_entry(p, &ctrl->subsys->hosts, entry) {
147 if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn))
148 continue;
149 host = p->host;
150 break;
151 }
152 if (!host) {
153 pr_debug("host %s not found\n", ctrl->hostnqn);
154 ret = NVME_AUTH_DHCHAP_FAILURE_FAILED;
155 goto out_unlock;
156 }
157
158 if (!reset && nvmet_queue_tls_keyid(sq)) {
159 pr_debug("host %s tls enabled\n", ctrl->hostnqn);
160 goto out_unlock;
161 }
162
163 ret = nvmet_setup_dhgroup(ctrl, host->dhchap_dhgroup_id);
164 if (ret < 0) {
165 pr_warn("Failed to setup DH group");
166 ret = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE;
167 goto out_unlock;
168 }
169
170 if (!host->dhchap_secret) {
171 pr_debug("No authentication provided\n");
172 goto out_unlock;
173 }
174
175 if (host->dhchap_hash_id == ctrl->shash_id) {
176 pr_debug("Re-use existing hash ID %d\n",
177 ctrl->shash_id);
178 } else {
179 ctrl->shash_id = host->dhchap_hash_id;
180 }
181
182 /* Skip the 'DHHC-1:XX:' prefix */
183 nvme_auth_free_key(ctrl->host_key);
184 ctrl->host_key = nvme_auth_extract_key(host->dhchap_secret + 10,
185 host->dhchap_key_hash);
186 if (IS_ERR(ctrl->host_key)) {
187 ret = NVME_AUTH_DHCHAP_FAILURE_NOT_USABLE;
188 ctrl->host_key = NULL;
189 goto out_free_hash;
190 }
191#ifdef CONFIG_NVME_TARGET_AUTH_DEBUG
192 pr_debug("%s: using hash %s key %*ph\n", __func__,
193 ctrl->host_key->hash > 0 ?
194 nvme_auth_hmac_name(ctrl->host_key->hash) : "none",
195 (int)ctrl->host_key->len, ctrl->host_key->key);
196#endif
197 nvme_auth_free_key(ctrl->ctrl_key);
198 if (!host->dhchap_ctrl_secret) {
199 ctrl->ctrl_key = NULL;
200 goto out_unlock;
201 }
202
203 ctrl->ctrl_key = nvme_auth_extract_key(host->dhchap_ctrl_secret + 10,
204 host->dhchap_ctrl_key_hash);
205 if (IS_ERR(ctrl->ctrl_key)) {
206 ret = NVME_AUTH_DHCHAP_FAILURE_NOT_USABLE;
207 ctrl->ctrl_key = NULL;
208 goto out_free_hash;
209 }
210#ifdef CONFIG_NVME_TARGET_AUTH_DEBUG
211 pr_debug("%s: using ctrl hash %s key %*ph\n", __func__,
212 ctrl->ctrl_key->hash > 0 ?
213 nvme_auth_hmac_name(ctrl->ctrl_key->hash) : "none",
214 (int)ctrl->ctrl_key->len, ctrl->ctrl_key->key);
215#endif
216out_free_hash:
217 if (ret) {
218 if (ctrl->host_key) {
219 nvme_auth_free_key(ctrl->host_key);
220 ctrl->host_key = NULL;
221 }
222 ctrl->shash_id = 0;
223 }
224out_unlock:
225 up_read(&nvmet_config_sem);
226
227 return ret;
228}
229
230void nvmet_auth_sq_free(struct nvmet_sq *sq)
231{
232 cancel_delayed_work(&sq->auth_expired_work);
233 kfree(sq->dhchap_c1);
234 sq->dhchap_c1 = NULL;
235 kfree(sq->dhchap_c2);
236 sq->dhchap_c2 = NULL;
237 kfree(sq->dhchap_skey);
238 sq->dhchap_skey = NULL;
239}
240
241void nvmet_auth_sq_destroy(struct nvmet_sq *sq)
242{
243 cancel_delayed_work_sync(&sq->auth_expired_work);
244 nvmet_auth_sq_free(sq);
245}
246
247void nvmet_destroy_auth(struct nvmet_ctrl *ctrl)
248{
249 ctrl->shash_id = 0;
250
251 if (ctrl->dh_tfm) {
252 crypto_free_kpp(ctrl->dh_tfm);
253 ctrl->dh_tfm = NULL;
254 ctrl->dh_gid = 0;
255 }
256 kfree_sensitive(ctrl->dh_key);
257 ctrl->dh_key = NULL;
258
259 if (ctrl->host_key) {
260 nvme_auth_free_key(ctrl->host_key);
261 ctrl->host_key = NULL;
262 }
263 if (ctrl->ctrl_key) {
264 nvme_auth_free_key(ctrl->ctrl_key);
265 ctrl->ctrl_key = NULL;
266 }
267#ifdef CONFIG_NVME_TARGET_TCP_TLS
268 if (ctrl->tls_key) {
269 key_put(ctrl->tls_key);
270 ctrl->tls_key = NULL;
271 }
272#endif
273}
274
275bool nvmet_check_auth_status(struct nvmet_req *req)
276{
277 if (req->sq->ctrl->host_key) {
278 if (req->sq->qid > 0)
279 return true;
280 if (!req->sq->authenticated)
281 return false;
282 }
283 return true;
284}
285
286int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
287 unsigned int shash_len)
288{
289 struct nvme_auth_hmac_ctx hmac;
290 struct nvmet_ctrl *ctrl = req->sq->ctrl;
291 u8 *challenge = req->sq->dhchap_c1;
292 struct nvme_dhchap_key *transformed_key;
293 u8 buf[4];
294 int ret;
295
296 transformed_key = nvme_auth_transform_key(ctrl->host_key,
297 ctrl->hostnqn);
298 if (IS_ERR(transformed_key))
299 return PTR_ERR(transformed_key);
300
301 ret = nvme_auth_hmac_init(&hmac, ctrl->shash_id, transformed_key->key,
302 transformed_key->len);
303 if (ret)
304 goto out_free_response;
305
306 if (shash_len != nvme_auth_hmac_hash_len(ctrl->shash_id)) {
307 pr_err("%s: hash len mismatch (len %u digest %zu)\n", __func__,
308 shash_len, nvme_auth_hmac_hash_len(ctrl->shash_id));
309 ret = -EINVAL;
310 goto out_free_response;
311 }
312
313 if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) {
314 challenge = kmalloc(shash_len, GFP_KERNEL);
315 if (!challenge) {
316 ret = -ENOMEM;
317 goto out_free_response;
318 }
319 ret = nvme_auth_augmented_challenge(ctrl->shash_id,
320 req->sq->dhchap_skey,
321 req->sq->dhchap_skey_len,
322 req->sq->dhchap_c1,
323 challenge, shash_len);
324 if (ret)
325 goto out_free_challenge;
326 }
327 pr_debug("ctrl %d qid %d host response seq %u transaction %d\n",
328 ctrl->cntlid, req->sq->qid, req->sq->dhchap_s1,
329 req->sq->dhchap_tid);
330
331 nvme_auth_hmac_update(&hmac, challenge, shash_len);
332
333 put_unaligned_le32(req->sq->dhchap_s1, buf);
334 nvme_auth_hmac_update(&hmac, buf, 4);
335
336 put_unaligned_le16(req->sq->dhchap_tid, buf);
337 nvme_auth_hmac_update(&hmac, buf, 2);
338
339 *buf = req->sq->sc_c;
340 nvme_auth_hmac_update(&hmac, buf, 1);
341 nvme_auth_hmac_update(&hmac, "HostHost", 8);
342 memset(buf, 0, 4);
343 nvme_auth_hmac_update(&hmac, ctrl->hostnqn, strlen(ctrl->hostnqn));
344 nvme_auth_hmac_update(&hmac, buf, 1);
345 nvme_auth_hmac_update(&hmac, ctrl->subsys->subsysnqn,
346 strlen(ctrl->subsys->subsysnqn));
347 nvme_auth_hmac_final(&hmac, response);
348 ret = 0;
349out_free_challenge:
350 if (challenge != req->sq->dhchap_c1)
351 kfree(challenge);
352out_free_response:
353 memzero_explicit(&hmac, sizeof(hmac));
354 nvme_auth_free_key(transformed_key);
355 return ret;
356}
357
358int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
359 unsigned int shash_len)
360{
361 struct nvme_auth_hmac_ctx hmac;
362 struct nvmet_ctrl *ctrl = req->sq->ctrl;
363 u8 *challenge = req->sq->dhchap_c2;
364 struct nvme_dhchap_key *transformed_key;
365 u8 buf[4];
366 int ret;
367
368 transformed_key = nvme_auth_transform_key(ctrl->ctrl_key,
369 ctrl->subsys->subsysnqn);
370 if (IS_ERR(transformed_key))
371 return PTR_ERR(transformed_key);
372
373 ret = nvme_auth_hmac_init(&hmac, ctrl->shash_id, transformed_key->key,
374 transformed_key->len);
375 if (ret)
376 goto out_free_response;
377
378 if (shash_len != nvme_auth_hmac_hash_len(ctrl->shash_id)) {
379 pr_err("%s: hash len mismatch (len %u digest %zu)\n", __func__,
380 shash_len, nvme_auth_hmac_hash_len(ctrl->shash_id));
381 ret = -EINVAL;
382 goto out_free_response;
383 }
384
385 if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) {
386 challenge = kmalloc(shash_len, GFP_KERNEL);
387 if (!challenge) {
388 ret = -ENOMEM;
389 goto out_free_response;
390 }
391 ret = nvme_auth_augmented_challenge(ctrl->shash_id,
392 req->sq->dhchap_skey,
393 req->sq->dhchap_skey_len,
394 req->sq->dhchap_c2,
395 challenge, shash_len);
396 if (ret)
397 goto out_free_challenge;
398 }
399
400 nvme_auth_hmac_update(&hmac, challenge, shash_len);
401
402 put_unaligned_le32(req->sq->dhchap_s2, buf);
403 nvme_auth_hmac_update(&hmac, buf, 4);
404
405 put_unaligned_le16(req->sq->dhchap_tid, buf);
406 nvme_auth_hmac_update(&hmac, buf, 2);
407
408 *buf = req->sq->sc_c;
409 nvme_auth_hmac_update(&hmac, buf, 1);
410 nvme_auth_hmac_update(&hmac, "Controller", 10);
411 nvme_auth_hmac_update(&hmac, ctrl->subsys->subsysnqn,
412 strlen(ctrl->subsys->subsysnqn));
413 memset(buf, 0, 4);
414 nvme_auth_hmac_update(&hmac, buf, 1);
415 nvme_auth_hmac_update(&hmac, ctrl->hostnqn, strlen(ctrl->hostnqn));
416 nvme_auth_hmac_final(&hmac, response);
417 ret = 0;
418out_free_challenge:
419 if (challenge != req->sq->dhchap_c2)
420 kfree(challenge);
421out_free_response:
422 memzero_explicit(&hmac, sizeof(hmac));
423 nvme_auth_free_key(transformed_key);
424 return ret;
425}
426
427int nvmet_auth_ctrl_exponential(struct nvmet_req *req,
428 u8 *buf, int buf_size)
429{
430 struct nvmet_ctrl *ctrl = req->sq->ctrl;
431 int ret = 0;
432
433 if (!ctrl->dh_key) {
434 pr_warn("ctrl %d no DH public key!\n", ctrl->cntlid);
435 return -ENOKEY;
436 }
437 if (buf_size != ctrl->dh_keysize) {
438 pr_warn("ctrl %d DH public key size mismatch, need %zu is %d\n",
439 ctrl->cntlid, ctrl->dh_keysize, buf_size);
440 ret = -EINVAL;
441 } else {
442 memcpy(buf, ctrl->dh_key, buf_size);
443#ifdef CONFIG_NVME_TARGET_AUTH_DEBUG
444 pr_debug("%s: ctrl %d public key %*ph\n", __func__,
445 ctrl->cntlid, (int)buf_size, buf);
446#endif
447 }
448
449 return ret;
450}
451
452int nvmet_auth_ctrl_sesskey(struct nvmet_req *req,
453 const u8 *pkey, int pkey_size)
454{
455 struct nvmet_ctrl *ctrl = req->sq->ctrl;
456 int ret;
457
458 req->sq->dhchap_skey_len = nvme_auth_hmac_hash_len(ctrl->shash_id);
459 req->sq->dhchap_skey = kzalloc(req->sq->dhchap_skey_len, GFP_KERNEL);
460 if (!req->sq->dhchap_skey)
461 return -ENOMEM;
462 ret = nvme_auth_gen_session_key(ctrl->dh_tfm,
463 pkey, pkey_size,
464 req->sq->dhchap_skey,
465 req->sq->dhchap_skey_len,
466 ctrl->shash_id);
467 if (ret)
468 pr_debug("failed to compute session key, err %d\n", ret);
469#ifdef CONFIG_NVME_TARGET_AUTH_DEBUG
470 else
471 pr_debug("%s: session key %*ph\n", __func__,
472 (int)req->sq->dhchap_skey_len,
473 req->sq->dhchap_skey);
474#endif
475 return ret;
476}
477
478void nvmet_auth_insert_psk(struct nvmet_sq *sq)
479{
480 int hash_len = nvme_auth_hmac_hash_len(sq->ctrl->shash_id);
481 u8 *psk, *tls_psk;
482 char *digest;
483 size_t psk_len;
484 int ret;
485#ifdef CONFIG_NVME_TARGET_TCP_TLS
486 struct key *tls_key = NULL;
487#endif
488
489 ret = nvme_auth_generate_psk(sq->ctrl->shash_id,
490 sq->dhchap_skey,
491 sq->dhchap_skey_len,
492 sq->dhchap_c1, sq->dhchap_c2,
493 hash_len, &psk, &psk_len);
494 if (ret) {
495 pr_warn("%s: ctrl %d qid %d failed to generate PSK, error %d\n",
496 __func__, sq->ctrl->cntlid, sq->qid, ret);
497 return;
498 }
499 ret = nvme_auth_generate_digest(sq->ctrl->shash_id, psk, psk_len,
500 sq->ctrl->subsys->subsysnqn,
501 sq->ctrl->hostnqn, &digest);
502 if (ret) {
503 pr_warn("%s: ctrl %d qid %d failed to generate digest, error %d\n",
504 __func__, sq->ctrl->cntlid, sq->qid, ret);
505 goto out_free_psk;
506 }
507 ret = nvme_auth_derive_tls_psk(sq->ctrl->shash_id, psk, psk_len,
508 digest, &tls_psk);
509 if (ret) {
510 pr_warn("%s: ctrl %d qid %d failed to derive TLS PSK, error %d\n",
511 __func__, sq->ctrl->cntlid, sq->qid, ret);
512 goto out_free_digest;
513 }
514#ifdef CONFIG_NVME_TARGET_TCP_TLS
515 tls_key = nvme_tls_psk_refresh(NULL, sq->ctrl->hostnqn,
516 sq->ctrl->subsys->subsysnqn,
517 sq->ctrl->shash_id, tls_psk, psk_len,
518 digest);
519 if (IS_ERR(tls_key)) {
520 pr_warn("%s: ctrl %d qid %d failed to refresh key, error %ld\n",
521 __func__, sq->ctrl->cntlid, sq->qid, PTR_ERR(tls_key));
522 tls_key = NULL;
523 }
524 if (sq->ctrl->tls_key)
525 key_put(sq->ctrl->tls_key);
526 sq->ctrl->tls_key = tls_key;
527#endif
528 kfree_sensitive(tls_psk);
529out_free_digest:
530 kfree_sensitive(digest);
531out_free_psk:
532 kfree_sensitive(psk);
533}