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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 <asm/unaligned.h>
12#include <crypto/hash.h>
13#include <crypto/dh.h>
14#include <linux/nvme.h>
15#include <linux/nvme-auth.h>
16
17static u32 nvme_dhchap_seqnum;
18static DEFINE_MUTEX(nvme_dhchap_mutex);
19
20u32 nvme_auth_get_seqnum(void)
21{
22 u32 seqnum;
23
24 mutex_lock(&nvme_dhchap_mutex);
25 if (!nvme_dhchap_seqnum)
26 nvme_dhchap_seqnum = get_random_u32();
27 else {
28 nvme_dhchap_seqnum++;
29 if (!nvme_dhchap_seqnum)
30 nvme_dhchap_seqnum++;
31 }
32 seqnum = nvme_dhchap_seqnum;
33 mutex_unlock(&nvme_dhchap_mutex);
34 return seqnum;
35}
36EXPORT_SYMBOL_GPL(nvme_auth_get_seqnum);
37
38static struct nvme_auth_dhgroup_map {
39 const char name[16];
40 const char kpp[16];
41} dhgroup_map[] = {
42 [NVME_AUTH_DHGROUP_NULL] = {
43 .name = "null", .kpp = "null" },
44 [NVME_AUTH_DHGROUP_2048] = {
45 .name = "ffdhe2048", .kpp = "ffdhe2048(dh)" },
46 [NVME_AUTH_DHGROUP_3072] = {
47 .name = "ffdhe3072", .kpp = "ffdhe3072(dh)" },
48 [NVME_AUTH_DHGROUP_4096] = {
49 .name = "ffdhe4096", .kpp = "ffdhe4096(dh)" },
50 [NVME_AUTH_DHGROUP_6144] = {
51 .name = "ffdhe6144", .kpp = "ffdhe6144(dh)" },
52 [NVME_AUTH_DHGROUP_8192] = {
53 .name = "ffdhe8192", .kpp = "ffdhe8192(dh)" },
54};
55
56const char *nvme_auth_dhgroup_name(u8 dhgroup_id)
57{
58 if (dhgroup_id >= ARRAY_SIZE(dhgroup_map))
59 return NULL;
60 return dhgroup_map[dhgroup_id].name;
61}
62EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_name);
63
64const char *nvme_auth_dhgroup_kpp(u8 dhgroup_id)
65{
66 if (dhgroup_id >= ARRAY_SIZE(dhgroup_map))
67 return NULL;
68 return dhgroup_map[dhgroup_id].kpp;
69}
70EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_kpp);
71
72u8 nvme_auth_dhgroup_id(const char *dhgroup_name)
73{
74 int i;
75
76 if (!dhgroup_name || !strlen(dhgroup_name))
77 return NVME_AUTH_DHGROUP_INVALID;
78 for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
79 if (!strlen(dhgroup_map[i].name))
80 continue;
81 if (!strncmp(dhgroup_map[i].name, dhgroup_name,
82 strlen(dhgroup_map[i].name)))
83 return i;
84 }
85 return NVME_AUTH_DHGROUP_INVALID;
86}
87EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_id);
88
89static struct nvme_dhchap_hash_map {
90 int len;
91 const char hmac[15];
92 const char digest[8];
93} hash_map[] = {
94 [NVME_AUTH_HASH_SHA256] = {
95 .len = 32,
96 .hmac = "hmac(sha256)",
97 .digest = "sha256",
98 },
99 [NVME_AUTH_HASH_SHA384] = {
100 .len = 48,
101 .hmac = "hmac(sha384)",
102 .digest = "sha384",
103 },
104 [NVME_AUTH_HASH_SHA512] = {
105 .len = 64,
106 .hmac = "hmac(sha512)",
107 .digest = "sha512",
108 },
109};
110
111const char *nvme_auth_hmac_name(u8 hmac_id)
112{
113 if (hmac_id >= ARRAY_SIZE(hash_map))
114 return NULL;
115 return hash_map[hmac_id].hmac;
116}
117EXPORT_SYMBOL_GPL(nvme_auth_hmac_name);
118
119const char *nvme_auth_digest_name(u8 hmac_id)
120{
121 if (hmac_id >= ARRAY_SIZE(hash_map))
122 return NULL;
123 return hash_map[hmac_id].digest;
124}
125EXPORT_SYMBOL_GPL(nvme_auth_digest_name);
126
127u8 nvme_auth_hmac_id(const char *hmac_name)
128{
129 int i;
130
131 if (!hmac_name || !strlen(hmac_name))
132 return NVME_AUTH_HASH_INVALID;
133
134 for (i = 0; i < ARRAY_SIZE(hash_map); i++) {
135 if (!strlen(hash_map[i].hmac))
136 continue;
137 if (!strncmp(hash_map[i].hmac, hmac_name,
138 strlen(hash_map[i].hmac)))
139 return i;
140 }
141 return NVME_AUTH_HASH_INVALID;
142}
143EXPORT_SYMBOL_GPL(nvme_auth_hmac_id);
144
145size_t nvme_auth_hmac_hash_len(u8 hmac_id)
146{
147 if (hmac_id >= ARRAY_SIZE(hash_map))
148 return 0;
149 return hash_map[hmac_id].len;
150}
151EXPORT_SYMBOL_GPL(nvme_auth_hmac_hash_len);
152
153struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
154 u8 key_hash)
155{
156 struct nvme_dhchap_key *key;
157 unsigned char *p;
158 u32 crc;
159 int ret, key_len;
160 size_t allocated_len = strlen(secret);
161
162 /* Secret might be affixed with a ':' */
163 p = strrchr(secret, ':');
164 if (p)
165 allocated_len = p - secret;
166 key = kzalloc(sizeof(*key), GFP_KERNEL);
167 if (!key)
168 return ERR_PTR(-ENOMEM);
169 key->key = kzalloc(allocated_len, GFP_KERNEL);
170 if (!key->key) {
171 ret = -ENOMEM;
172 goto out_free_key;
173 }
174
175 key_len = base64_decode(secret, allocated_len, key->key);
176 if (key_len < 0) {
177 pr_debug("base64 key decoding error %d\n",
178 key_len);
179 ret = key_len;
180 goto out_free_secret;
181 }
182
183 if (key_len != 36 && key_len != 52 &&
184 key_len != 68) {
185 pr_err("Invalid key len %d\n", key_len);
186 ret = -EINVAL;
187 goto out_free_secret;
188 }
189
190 if (key_hash > 0 &&
191 (key_len - 4) != nvme_auth_hmac_hash_len(key_hash)) {
192 pr_err("Mismatched key len %d for %s\n", key_len,
193 nvme_auth_hmac_name(key_hash));
194 ret = -EINVAL;
195 goto out_free_secret;
196 }
197
198 /* The last four bytes is the CRC in little-endian format */
199 key_len -= 4;
200 /*
201 * The linux implementation doesn't do pre- and post-increments,
202 * so we have to do it manually.
203 */
204 crc = ~crc32(~0, key->key, key_len);
205
206 if (get_unaligned_le32(key->key + key_len) != crc) {
207 pr_err("key crc mismatch (key %08x, crc %08x)\n",
208 get_unaligned_le32(key->key + key_len), crc);
209 ret = -EKEYREJECTED;
210 goto out_free_secret;
211 }
212 key->len = key_len;
213 key->hash = key_hash;
214 return key;
215out_free_secret:
216 kfree_sensitive(key->key);
217out_free_key:
218 kfree(key);
219 return ERR_PTR(ret);
220}
221EXPORT_SYMBOL_GPL(nvme_auth_extract_key);
222
223void nvme_auth_free_key(struct nvme_dhchap_key *key)
224{
225 if (!key)
226 return;
227 kfree_sensitive(key->key);
228 kfree(key);
229}
230EXPORT_SYMBOL_GPL(nvme_auth_free_key);
231
232u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
233{
234 const char *hmac_name;
235 struct crypto_shash *key_tfm;
236 struct shash_desc *shash;
237 u8 *transformed_key;
238 int ret;
239
240 if (!key || !key->key) {
241 pr_warn("No key specified\n");
242 return ERR_PTR(-ENOKEY);
243 }
244 if (key->hash == 0) {
245 transformed_key = kmemdup(key->key, key->len, GFP_KERNEL);
246 return transformed_key ? transformed_key : ERR_PTR(-ENOMEM);
247 }
248 hmac_name = nvme_auth_hmac_name(key->hash);
249 if (!hmac_name) {
250 pr_warn("Invalid key hash id %d\n", key->hash);
251 return ERR_PTR(-EINVAL);
252 }
253
254 key_tfm = crypto_alloc_shash(hmac_name, 0, 0);
255 if (IS_ERR(key_tfm))
256 return (u8 *)key_tfm;
257
258 shash = kmalloc(sizeof(struct shash_desc) +
259 crypto_shash_descsize(key_tfm),
260 GFP_KERNEL);
261 if (!shash) {
262 ret = -ENOMEM;
263 goto out_free_key;
264 }
265
266 transformed_key = kzalloc(crypto_shash_digestsize(key_tfm), GFP_KERNEL);
267 if (!transformed_key) {
268 ret = -ENOMEM;
269 goto out_free_shash;
270 }
271
272 shash->tfm = key_tfm;
273 ret = crypto_shash_setkey(key_tfm, key->key, key->len);
274 if (ret < 0)
275 goto out_free_transformed_key;
276 ret = crypto_shash_init(shash);
277 if (ret < 0)
278 goto out_free_transformed_key;
279 ret = crypto_shash_update(shash, nqn, strlen(nqn));
280 if (ret < 0)
281 goto out_free_transformed_key;
282 ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17);
283 if (ret < 0)
284 goto out_free_transformed_key;
285 ret = crypto_shash_final(shash, transformed_key);
286 if (ret < 0)
287 goto out_free_transformed_key;
288
289 kfree(shash);
290 crypto_free_shash(key_tfm);
291
292 return transformed_key;
293
294out_free_transformed_key:
295 kfree_sensitive(transformed_key);
296out_free_shash:
297 kfree(shash);
298out_free_key:
299 crypto_free_shash(key_tfm);
300
301 return ERR_PTR(ret);
302}
303EXPORT_SYMBOL_GPL(nvme_auth_transform_key);
304
305static int nvme_auth_hash_skey(int hmac_id, u8 *skey, size_t skey_len, u8 *hkey)
306{
307 const char *digest_name;
308 struct crypto_shash *tfm;
309 int ret;
310
311 digest_name = nvme_auth_digest_name(hmac_id);
312 if (!digest_name) {
313 pr_debug("%s: failed to get digest for %d\n", __func__,
314 hmac_id);
315 return -EINVAL;
316 }
317 tfm = crypto_alloc_shash(digest_name, 0, 0);
318 if (IS_ERR(tfm))
319 return -ENOMEM;
320
321 ret = crypto_shash_tfm_digest(tfm, skey, skey_len, hkey);
322 if (ret < 0)
323 pr_debug("%s: Failed to hash digest len %zu\n", __func__,
324 skey_len);
325
326 crypto_free_shash(tfm);
327 return ret;
328}
329
330int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len,
331 u8 *challenge, u8 *aug, size_t hlen)
332{
333 struct crypto_shash *tfm;
334 struct shash_desc *desc;
335 u8 *hashed_key;
336 const char *hmac_name;
337 int ret;
338
339 hashed_key = kmalloc(hlen, GFP_KERNEL);
340 if (!hashed_key)
341 return -ENOMEM;
342
343 ret = nvme_auth_hash_skey(hmac_id, skey,
344 skey_len, hashed_key);
345 if (ret < 0)
346 goto out_free_key;
347
348 hmac_name = nvme_auth_hmac_name(hmac_id);
349 if (!hmac_name) {
350 pr_warn("%s: invalid hash algorithm %d\n",
351 __func__, hmac_id);
352 ret = -EINVAL;
353 goto out_free_key;
354 }
355
356 tfm = crypto_alloc_shash(hmac_name, 0, 0);
357 if (IS_ERR(tfm)) {
358 ret = PTR_ERR(tfm);
359 goto out_free_key;
360 }
361
362 desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
363 GFP_KERNEL);
364 if (!desc) {
365 ret = -ENOMEM;
366 goto out_free_hash;
367 }
368 desc->tfm = tfm;
369
370 ret = crypto_shash_setkey(tfm, hashed_key, hlen);
371 if (ret)
372 goto out_free_desc;
373
374 ret = crypto_shash_init(desc);
375 if (ret)
376 goto out_free_desc;
377
378 ret = crypto_shash_update(desc, challenge, hlen);
379 if (ret)
380 goto out_free_desc;
381
382 ret = crypto_shash_final(desc, aug);
383out_free_desc:
384 kfree_sensitive(desc);
385out_free_hash:
386 crypto_free_shash(tfm);
387out_free_key:
388 kfree_sensitive(hashed_key);
389 return ret;
390}
391EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge);
392
393int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, u8 dh_gid)
394{
395 int ret;
396
397 ret = crypto_kpp_set_secret(dh_tfm, NULL, 0);
398 if (ret)
399 pr_debug("failed to set private key, error %d\n", ret);
400
401 return ret;
402}
403EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey);
404
405int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm,
406 u8 *host_key, size_t host_key_len)
407{
408 struct kpp_request *req;
409 struct crypto_wait wait;
410 struct scatterlist dst;
411 int ret;
412
413 req = kpp_request_alloc(dh_tfm, GFP_KERNEL);
414 if (!req)
415 return -ENOMEM;
416
417 crypto_init_wait(&wait);
418 kpp_request_set_input(req, NULL, 0);
419 sg_init_one(&dst, host_key, host_key_len);
420 kpp_request_set_output(req, &dst, host_key_len);
421 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
422 crypto_req_done, &wait);
423
424 ret = crypto_wait_req(crypto_kpp_generate_public_key(req), &wait);
425 kpp_request_free(req);
426 return ret;
427}
428EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey);
429
430int nvme_auth_gen_shared_secret(struct crypto_kpp *dh_tfm,
431 u8 *ctrl_key, size_t ctrl_key_len,
432 u8 *sess_key, size_t sess_key_len)
433{
434 struct kpp_request *req;
435 struct crypto_wait wait;
436 struct scatterlist src, dst;
437 int ret;
438
439 req = kpp_request_alloc(dh_tfm, GFP_KERNEL);
440 if (!req)
441 return -ENOMEM;
442
443 crypto_init_wait(&wait);
444 sg_init_one(&src, ctrl_key, ctrl_key_len);
445 kpp_request_set_input(req, &src, ctrl_key_len);
446 sg_init_one(&dst, sess_key, sess_key_len);
447 kpp_request_set_output(req, &dst, sess_key_len);
448 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
449 crypto_req_done, &wait);
450
451 ret = crypto_wait_req(crypto_kpp_compute_shared_secret(req), &wait);
452
453 kpp_request_free(req);
454 return ret;
455}
456EXPORT_SYMBOL_GPL(nvme_auth_gen_shared_secret);
457
458int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key)
459{
460 struct nvme_dhchap_key *key;
461 u8 key_hash;
462
463 if (!secret) {
464 *ret_key = NULL;
465 return 0;
466 }
467
468 if (sscanf(secret, "DHHC-1:%hhd:%*s:", &key_hash) != 1)
469 return -EINVAL;
470
471 /* Pass in the secret without the 'DHHC-1:XX:' prefix */
472 key = nvme_auth_extract_key(secret + 10, key_hash);
473 if (IS_ERR(key)) {
474 *ret_key = NULL;
475 return PTR_ERR(key);
476 }
477
478 *ret_key = key;
479 return 0;
480}
481EXPORT_SYMBOL_GPL(nvme_auth_generate_key);
482
483MODULE_LICENSE("GPL v2");