Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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 pr_debug("check %s\n", nvmet_host_name(p->host));
148 if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn))
149 continue;
150 host = p->host;
151 break;
152 }
153 if (!host) {
154 pr_debug("host %s not found\n", ctrl->hostnqn);
155 ret = NVME_AUTH_DHCHAP_FAILURE_FAILED;
156 goto out_unlock;
157 }
158
159 if (!reset && nvmet_queue_tls_keyid(sq)) {
160 pr_debug("host %s tls enabled\n", ctrl->hostnqn);
161 goto out_unlock;
162 }
163
164 ret = nvmet_setup_dhgroup(ctrl, host->dhchap_dhgroup_id);
165 if (ret < 0) {
166 pr_warn("Failed to setup DH group");
167 ret = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE;
168 goto out_unlock;
169 }
170
171 if (!host->dhchap_secret) {
172 pr_debug("No authentication provided\n");
173 goto out_unlock;
174 }
175
176 if (host->dhchap_hash_id == ctrl->shash_id) {
177 pr_debug("Re-use existing hash ID %d\n",
178 ctrl->shash_id);
179 } else {
180 ctrl->shash_id = host->dhchap_hash_id;
181 }
182
183 /* Skip the 'DHHC-1:XX:' prefix */
184 nvme_auth_free_key(ctrl->host_key);
185 ctrl->host_key = nvme_auth_extract_key(host->dhchap_secret + 10,
186 host->dhchap_key_hash);
187 if (IS_ERR(ctrl->host_key)) {
188 ret = NVME_AUTH_DHCHAP_FAILURE_NOT_USABLE;
189 ctrl->host_key = NULL;
190 goto out_free_hash;
191 }
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
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 pr_debug("%s: using ctrl hash %s key %*ph\n", __func__,
211 ctrl->ctrl_key->hash > 0 ?
212 nvme_auth_hmac_name(ctrl->ctrl_key->hash) : "none",
213 (int)ctrl->ctrl_key->len, ctrl->ctrl_key->key);
214
215out_free_hash:
216 if (ret) {
217 if (ctrl->host_key) {
218 nvme_auth_free_key(ctrl->host_key);
219 ctrl->host_key = NULL;
220 }
221 ctrl->shash_id = 0;
222 }
223out_unlock:
224 up_read(&nvmet_config_sem);
225
226 return ret;
227}
228
229void nvmet_auth_sq_free(struct nvmet_sq *sq)
230{
231 cancel_delayed_work(&sq->auth_expired_work);
232 kfree(sq->dhchap_c1);
233 sq->dhchap_c1 = NULL;
234 kfree(sq->dhchap_c2);
235 sq->dhchap_c2 = NULL;
236 kfree(sq->dhchap_skey);
237 sq->dhchap_skey = NULL;
238}
239
240void nvmet_destroy_auth(struct nvmet_ctrl *ctrl)
241{
242 ctrl->shash_id = 0;
243
244 if (ctrl->dh_tfm) {
245 crypto_free_kpp(ctrl->dh_tfm);
246 ctrl->dh_tfm = NULL;
247 ctrl->dh_gid = 0;
248 }
249 kfree_sensitive(ctrl->dh_key);
250 ctrl->dh_key = NULL;
251
252 if (ctrl->host_key) {
253 nvme_auth_free_key(ctrl->host_key);
254 ctrl->host_key = NULL;
255 }
256 if (ctrl->ctrl_key) {
257 nvme_auth_free_key(ctrl->ctrl_key);
258 ctrl->ctrl_key = NULL;
259 }
260#ifdef CONFIG_NVME_TARGET_TCP_TLS
261 if (ctrl->tls_key) {
262 key_put(ctrl->tls_key);
263 ctrl->tls_key = NULL;
264 }
265#endif
266}
267
268bool nvmet_check_auth_status(struct nvmet_req *req)
269{
270 if (req->sq->ctrl->host_key) {
271 if (req->sq->qid > 0)
272 return true;
273 if (!req->sq->authenticated)
274 return false;
275 }
276 return true;
277}
278
279int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
280 unsigned int shash_len)
281{
282 struct nvme_auth_hmac_ctx hmac;
283 struct nvmet_ctrl *ctrl = req->sq->ctrl;
284 u8 *challenge = req->sq->dhchap_c1;
285 struct nvme_dhchap_key *transformed_key;
286 u8 buf[4];
287 int ret;
288
289 transformed_key = nvme_auth_transform_key(ctrl->host_key,
290 ctrl->hostnqn);
291 if (IS_ERR(transformed_key))
292 return PTR_ERR(transformed_key);
293
294 ret = nvme_auth_hmac_init(&hmac, ctrl->shash_id, transformed_key->key,
295 transformed_key->len);
296 if (ret)
297 goto out_free_response;
298
299 if (shash_len != nvme_auth_hmac_hash_len(ctrl->shash_id)) {
300 pr_err("%s: hash len mismatch (len %u digest %zu)\n", __func__,
301 shash_len, nvme_auth_hmac_hash_len(ctrl->shash_id));
302 ret = -EINVAL;
303 goto out_free_response;
304 }
305
306 if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) {
307 challenge = kmalloc(shash_len, GFP_KERNEL);
308 if (!challenge) {
309 ret = -ENOMEM;
310 goto out_free_response;
311 }
312 ret = nvme_auth_augmented_challenge(ctrl->shash_id,
313 req->sq->dhchap_skey,
314 req->sq->dhchap_skey_len,
315 req->sq->dhchap_c1,
316 challenge, shash_len);
317 if (ret)
318 goto out_free_challenge;
319 }
320
321 pr_debug("ctrl %d qid %d host response seq %u transaction %d\n",
322 ctrl->cntlid, req->sq->qid, req->sq->dhchap_s1,
323 req->sq->dhchap_tid);
324
325 nvme_auth_hmac_update(&hmac, challenge, shash_len);
326
327 put_unaligned_le32(req->sq->dhchap_s1, buf);
328 nvme_auth_hmac_update(&hmac, buf, 4);
329
330 put_unaligned_le16(req->sq->dhchap_tid, buf);
331 nvme_auth_hmac_update(&hmac, buf, 2);
332
333 *buf = req->sq->sc_c;
334 nvme_auth_hmac_update(&hmac, buf, 1);
335 nvme_auth_hmac_update(&hmac, "HostHost", 8);
336 memset(buf, 0, 4);
337 nvme_auth_hmac_update(&hmac, ctrl->hostnqn, strlen(ctrl->hostnqn));
338 nvme_auth_hmac_update(&hmac, buf, 1);
339 nvme_auth_hmac_update(&hmac, ctrl->subsys->subsysnqn,
340 strlen(ctrl->subsys->subsysnqn));
341 nvme_auth_hmac_final(&hmac, response);
342 ret = 0;
343out_free_challenge:
344 if (challenge != req->sq->dhchap_c1)
345 kfree(challenge);
346out_free_response:
347 memzero_explicit(&hmac, sizeof(hmac));
348 nvme_auth_free_key(transformed_key);
349 return ret;
350}
351
352int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
353 unsigned int shash_len)
354{
355 struct nvme_auth_hmac_ctx hmac;
356 struct nvmet_ctrl *ctrl = req->sq->ctrl;
357 u8 *challenge = req->sq->dhchap_c2;
358 struct nvme_dhchap_key *transformed_key;
359 u8 buf[4];
360 int ret;
361
362 transformed_key = nvme_auth_transform_key(ctrl->ctrl_key,
363 ctrl->subsys->subsysnqn);
364 if (IS_ERR(transformed_key))
365 return PTR_ERR(transformed_key);
366
367 ret = nvme_auth_hmac_init(&hmac, ctrl->shash_id, transformed_key->key,
368 transformed_key->len);
369 if (ret)
370 goto out_free_response;
371
372 if (shash_len != nvme_auth_hmac_hash_len(ctrl->shash_id)) {
373 pr_err("%s: hash len mismatch (len %u digest %zu)\n", __func__,
374 shash_len, nvme_auth_hmac_hash_len(ctrl->shash_id));
375 ret = -EINVAL;
376 goto out_free_response;
377 }
378
379 if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) {
380 challenge = kmalloc(shash_len, GFP_KERNEL);
381 if (!challenge) {
382 ret = -ENOMEM;
383 goto out_free_response;
384 }
385 ret = nvme_auth_augmented_challenge(ctrl->shash_id,
386 req->sq->dhchap_skey,
387 req->sq->dhchap_skey_len,
388 req->sq->dhchap_c2,
389 challenge, shash_len);
390 if (ret)
391 goto out_free_challenge;
392 }
393
394 nvme_auth_hmac_update(&hmac, challenge, shash_len);
395
396 put_unaligned_le32(req->sq->dhchap_s2, buf);
397 nvme_auth_hmac_update(&hmac, buf, 4);
398
399 put_unaligned_le16(req->sq->dhchap_tid, buf);
400 nvme_auth_hmac_update(&hmac, buf, 2);
401
402 *buf = req->sq->sc_c;
403 nvme_auth_hmac_update(&hmac, buf, 1);
404 nvme_auth_hmac_update(&hmac, "Controller", 10);
405 nvme_auth_hmac_update(&hmac, ctrl->subsys->subsysnqn,
406 strlen(ctrl->subsys->subsysnqn));
407 memset(buf, 0, 4);
408 nvme_auth_hmac_update(&hmac, buf, 1);
409 nvme_auth_hmac_update(&hmac, ctrl->hostnqn, strlen(ctrl->hostnqn));
410 nvme_auth_hmac_final(&hmac, response);
411 ret = 0;
412out_free_challenge:
413 if (challenge != req->sq->dhchap_c2)
414 kfree(challenge);
415out_free_response:
416 memzero_explicit(&hmac, sizeof(hmac));
417 nvme_auth_free_key(transformed_key);
418 return ret;
419}
420
421int nvmet_auth_ctrl_exponential(struct nvmet_req *req,
422 u8 *buf, int buf_size)
423{
424 struct nvmet_ctrl *ctrl = req->sq->ctrl;
425 int ret = 0;
426
427 if (!ctrl->dh_key) {
428 pr_warn("ctrl %d no DH public key!\n", ctrl->cntlid);
429 return -ENOKEY;
430 }
431 if (buf_size != ctrl->dh_keysize) {
432 pr_warn("ctrl %d DH public key size mismatch, need %zu is %d\n",
433 ctrl->cntlid, ctrl->dh_keysize, buf_size);
434 ret = -EINVAL;
435 } else {
436 memcpy(buf, ctrl->dh_key, buf_size);
437 pr_debug("%s: ctrl %d public key %*ph\n", __func__,
438 ctrl->cntlid, (int)buf_size, buf);
439 }
440
441 return ret;
442}
443
444int nvmet_auth_ctrl_sesskey(struct nvmet_req *req,
445 const u8 *pkey, int pkey_size)
446{
447 struct nvmet_ctrl *ctrl = req->sq->ctrl;
448 int ret;
449
450 req->sq->dhchap_skey_len = nvme_auth_hmac_hash_len(ctrl->shash_id);
451 req->sq->dhchap_skey = kzalloc(req->sq->dhchap_skey_len, GFP_KERNEL);
452 if (!req->sq->dhchap_skey)
453 return -ENOMEM;
454 ret = nvme_auth_gen_session_key(ctrl->dh_tfm,
455 pkey, pkey_size,
456 req->sq->dhchap_skey,
457 req->sq->dhchap_skey_len,
458 ctrl->shash_id);
459 if (ret)
460 pr_debug("failed to compute session key, err %d\n", ret);
461 else
462 pr_debug("%s: session key %*ph\n", __func__,
463 (int)req->sq->dhchap_skey_len,
464 req->sq->dhchap_skey);
465
466 return ret;
467}
468
469void nvmet_auth_insert_psk(struct nvmet_sq *sq)
470{
471 int hash_len = nvme_auth_hmac_hash_len(sq->ctrl->shash_id);
472 u8 *psk, *tls_psk;
473 char *digest;
474 size_t psk_len;
475 int ret;
476#ifdef CONFIG_NVME_TARGET_TCP_TLS
477 struct key *tls_key = NULL;
478#endif
479
480 ret = nvme_auth_generate_psk(sq->ctrl->shash_id,
481 sq->dhchap_skey,
482 sq->dhchap_skey_len,
483 sq->dhchap_c1, sq->dhchap_c2,
484 hash_len, &psk, &psk_len);
485 if (ret) {
486 pr_warn("%s: ctrl %d qid %d failed to generate PSK, error %d\n",
487 __func__, sq->ctrl->cntlid, sq->qid, ret);
488 return;
489 }
490 ret = nvme_auth_generate_digest(sq->ctrl->shash_id, psk, psk_len,
491 sq->ctrl->subsys->subsysnqn,
492 sq->ctrl->hostnqn, &digest);
493 if (ret) {
494 pr_warn("%s: ctrl %d qid %d failed to generate digest, error %d\n",
495 __func__, sq->ctrl->cntlid, sq->qid, ret);
496 goto out_free_psk;
497 }
498 ret = nvme_auth_derive_tls_psk(sq->ctrl->shash_id, psk, psk_len,
499 digest, &tls_psk);
500 if (ret) {
501 pr_warn("%s: ctrl %d qid %d failed to derive TLS PSK, error %d\n",
502 __func__, sq->ctrl->cntlid, sq->qid, ret);
503 goto out_free_digest;
504 }
505#ifdef CONFIG_NVME_TARGET_TCP_TLS
506 tls_key = nvme_tls_psk_refresh(NULL, sq->ctrl->hostnqn,
507 sq->ctrl->subsys->subsysnqn,
508 sq->ctrl->shash_id, tls_psk, psk_len,
509 digest);
510 if (IS_ERR(tls_key)) {
511 pr_warn("%s: ctrl %d qid %d failed to refresh key, error %ld\n",
512 __func__, sq->ctrl->cntlid, sq->qid, PTR_ERR(tls_key));
513 tls_key = NULL;
514 }
515 if (sq->ctrl->tls_key)
516 key_put(sq->ctrl->tls_key);
517 sq->ctrl->tls_key = tls_key;
518#endif
519 kfree_sensitive(tls_psk);
520out_free_digest:
521 kfree_sensitive(digest);
522out_free_psk:
523 kfree_sensitive(psk);
524}