summaryrefslogtreecommitdiffstats
path: root/drivers/nvme/common/auth.c
blob: 04bd28f17dccea86d7e41ce4613beee1c268a191 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2020 Hannes Reinecke, SUSE Linux
 */

#include <linux/module.h>
#include <linux/crc32.h>
#include <linux/base64.h>
#include <linux/prandom.h>
#include <linux/scatterlist.h>
#include <asm/unaligned.h>
#include <crypto/hash.h>
#include <crypto/dh.h>
#include <linux/nvme.h>
#include <linux/nvme-auth.h>

static u32 nvme_dhchap_seqnum;
static DEFINE_MUTEX(nvme_dhchap_mutex);

u32 nvme_auth_get_seqnum(void)
{
	u32 seqnum;

	mutex_lock(&nvme_dhchap_mutex);
	if (!nvme_dhchap_seqnum)
		nvme_dhchap_seqnum = prandom_u32();
	else {
		nvme_dhchap_seqnum++;
		if (!nvme_dhchap_seqnum)
			nvme_dhchap_seqnum++;
	}
	seqnum = nvme_dhchap_seqnum;
	mutex_unlock(&nvme_dhchap_mutex);
	return seqnum;
}
EXPORT_SYMBOL_GPL(nvme_auth_get_seqnum);

static struct nvme_auth_dhgroup_map {
	const char name[16];
	const char kpp[16];
} dhgroup_map[] = {
	[NVME_AUTH_DHGROUP_NULL] = {
		.name = "null", .kpp = "null" },
	[NVME_AUTH_DHGROUP_2048] = {
		.name = "ffdhe2048", .kpp = "ffdhe2048(dh)" },
	[NVME_AUTH_DHGROUP_3072] = {
		.name = "ffdhe3072", .kpp = "ffdhe3072(dh)" },
	[NVME_AUTH_DHGROUP_4096] = {
		.name = "ffdhe4096", .kpp = "ffdhe4096(dh)" },
	[NVME_AUTH_DHGROUP_6144] = {
		.name = "ffdhe6144", .kpp = "ffdhe6144(dh)" },
	[NVME_AUTH_DHGROUP_8192] = {
		.name = "ffdhe8192", .kpp = "ffdhe8192(dh)" },
};

const char *nvme_auth_dhgroup_name(u8 dhgroup_id)
{
	if (dhgroup_id >= ARRAY_SIZE(dhgroup_map))
		return NULL;
	return dhgroup_map[dhgroup_id].name;
}
EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_name);

const char *nvme_auth_dhgroup_kpp(u8 dhgroup_id)
{
	if (dhgroup_id >= ARRAY_SIZE(dhgroup_map))
		return NULL;
	return dhgroup_map[dhgroup_id].kpp;
}
EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_kpp);

u8 nvme_auth_dhgroup_id(const char *dhgroup_name)
{
	int i;

	if (!dhgroup_name || !strlen(dhgroup_name))
		return NVME_AUTH_DHGROUP_INVALID;
	for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
		if (!strlen(dhgroup_map[i].name))
			continue;
		if (!strncmp(dhgroup_map[i].name, dhgroup_name,
			     strlen(dhgroup_map[i].name)))
			return i;
	}
	return NVME_AUTH_DHGROUP_INVALID;
}
EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_id);

static struct nvme_dhchap_hash_map {
	int len;
	const char hmac[15];
	const char digest[8];
} hash_map[] = {
	[NVME_AUTH_HASH_SHA256] = {
		.len = 32,
		.hmac = "hmac(sha256)",
		.digest = "sha256",
	},
	[NVME_AUTH_HASH_SHA384] = {
		.len = 48,
		.hmac = "hmac(sha384)",
		.digest = "sha384",
	},
	[NVME_AUTH_HASH_SHA512] = {
		.len = 64,
		.hmac = "hmac(sha512)",
		.digest = "sha512",
	},
};

const char *nvme_auth_hmac_name(u8 hmac_id)
{
	if (hmac_id >= ARRAY_SIZE(hash_map))
		return NULL;
	return hash_map[hmac_id].hmac;
}
EXPORT_SYMBOL_GPL(nvme_auth_hmac_name);

const char *nvme_auth_digest_name(u8 hmac_id)
{
	if (hmac_id >= ARRAY_SIZE(hash_map))
		return NULL;
	return hash_map[hmac_id].digest;
}
EXPORT_SYMBOL_GPL(nvme_auth_digest_name);

u8 nvme_auth_hmac_id(const char *hmac_name)
{
	int i;

	if (!hmac_name || !strlen(hmac_name))
		return NVME_AUTH_HASH_INVALID;

	for (i = 0; i < ARRAY_SIZE(hash_map); i++) {
		if (!strlen(hash_map[i].hmac))
			continue;
		if (!strncmp(hash_map[i].hmac, hmac_name,
			     strlen(hash_map[i].hmac)))
			return i;
	}
	return NVME_AUTH_HASH_INVALID;
}
EXPORT_SYMBOL_GPL(nvme_auth_hmac_id);

size_t nvme_auth_hmac_hash_len(u8 hmac_id)
{
	if (hmac_id >= ARRAY_SIZE(hash_map))
		return 0;
	return hash_map[hmac_id].len;
}
EXPORT_SYMBOL_GPL(nvme_auth_hmac_hash_len);

struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
					      u8 key_hash)
{
	struct nvme_dhchap_key *key;
	unsigned char *p;
	u32 crc;
	int ret, key_len;
	size_t allocated_len = strlen(secret);

	/* Secret might be affixed with a ':' */
	p = strrchr(secret, ':');
	if (p)
		allocated_len = p - secret;
	key = kzalloc(sizeof(*key), GFP_KERNEL);
	if (!key)
		return ERR_PTR(-ENOMEM);
	key->key = kzalloc(allocated_len, GFP_KERNEL);
	if (!key->key) {
		ret = -ENOMEM;
		goto out_free_key;
	}

	key_len = base64_decode(secret, allocated_len, key->key);
	if (key_len < 0) {
		pr_debug("base64 key decoding error %d\n",
			 key_len);
		ret = key_len;
		goto out_free_secret;
	}

	if (key_len != 36 && key_len != 52 &&
	    key_len != 68) {
		pr_err("Invalid key len %d\n", key_len);
		ret = -EINVAL;
		goto out_free_secret;
	}

	if (key_hash > 0 &&
	    (key_len - 4) != nvme_auth_hmac_hash_len(key_hash)) {
		pr_err("Mismatched key len %d for %s\n", key_len,
		       nvme_auth_hmac_name(key_hash));
		ret = -EINVAL;
		goto out_free_secret;
	}

	/* The last four bytes is the CRC in little-endian format */
	key_len -= 4;
	/*
	 * The linux implementation doesn't do pre- and post-increments,
	 * so we have to do it manually.
	 */
	crc = ~crc32(~0, key->key, key_len);

	if (get_unaligned_le32(key->key + key_len) != crc) {
		pr_err("key crc mismatch (key %08x, crc %08x)\n",
		       get_unaligned_le32(key->key + key_len), crc);
		ret = -EKEYREJECTED;
		goto out_free_secret;
	}
	key->len = key_len;
	key->hash = key_hash;
	return key;
out_free_secret:
	kfree_sensitive(key->key);
out_free_key:
	kfree(key);
	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(nvme_auth_extract_key);

void nvme_auth_free_key(struct nvme_dhchap_key *key)
{
	if (!key)
		return;
	kfree_sensitive(key->key);
	kfree(key);
}
EXPORT_SYMBOL_GPL(nvme_auth_free_key);

u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
{
	const char *hmac_name;
	struct crypto_shash *key_tfm;
	struct shash_desc *shash;
	u8 *transformed_key;
	int ret;

	if (!key || !key->key) {
		pr_warn("No key specified\n");
		return ERR_PTR(-ENOKEY);
	}
	if (key->hash == 0) {
		transformed_key = kmemdup(key->key, key->len, GFP_KERNEL);
		return transformed_key ? transformed_key : ERR_PTR(-ENOMEM);
	}
	hmac_name = nvme_auth_hmac_name(key->hash);
	if (!hmac_name) {
		pr_warn("Invalid key hash id %d\n", key->hash);
		return ERR_PTR(-EINVAL);
	}

	key_tfm = crypto_alloc_shash(hmac_name, 0, 0);
	if (IS_ERR(key_tfm))
		return (u8 *)key_tfm;

	shash = kmalloc(sizeof(struct shash_desc) +
			crypto_shash_descsize(key_tfm),
			GFP_KERNEL);
	if (!shash) {
		ret = -ENOMEM;
		goto out_free_key;
	}

	transformed_key = kzalloc(crypto_shash_digestsize(key_tfm), GFP_KERNEL);
	if (!transformed_key) {
		ret = -ENOMEM;
		goto out_free_shash;
	}

	shash->tfm = key_tfm;
	ret = crypto_shash_setkey(key_tfm, key->key, key->len);
	if (ret < 0)
		goto out_free_transformed_key;
	ret = crypto_shash_init(shash);
	if (ret < 0)
		goto out_free_transformed_key;
	ret = crypto_shash_update(shash, nqn, strlen(nqn));
	if (ret < 0)
		goto out_free_transformed_key;
	ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17);
	if (ret < 0)
		goto out_free_transformed_key;
	ret = crypto_shash_final(shash, transformed_key);
	if (ret < 0)
		goto out_free_transformed_key;

	kfree(shash);
	crypto_free_shash(key_tfm);

	return transformed_key;

out_free_transformed_key:
	kfree_sensitive(transformed_key);
out_free_shash:
	kfree(shash);
out_free_key:
	crypto_free_shash(key_tfm);

	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(nvme_auth_transform_key);

static int nvme_auth_hash_skey(int hmac_id, u8 *skey, size_t skey_len, u8 *hkey)
{
	const char *digest_name;
	struct crypto_shash *tfm;
	int ret;

	digest_name = nvme_auth_digest_name(hmac_id);
	if (!digest_name) {
		pr_debug("%s: failed to get digest for %d\n", __func__,
			 hmac_id);
		return -EINVAL;
	}
	tfm = crypto_alloc_shash(digest_name, 0, 0);
	if (IS_ERR(tfm))
		return -ENOMEM;

	ret = crypto_shash_tfm_digest(tfm, skey, skey_len, hkey);
	if (ret < 0)
		pr_debug("%s: Failed to hash digest len %zu\n", __func__,
			 skey_len);

	crypto_free_shash(tfm);
	return ret;
}

int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len,
		u8 *challenge, u8 *aug, size_t hlen)
{
	struct crypto_shash *tfm;
	struct shash_desc *desc;
	u8 *hashed_key;
	const char *hmac_name;
	int ret;

	hashed_key = kmalloc(hlen, GFP_KERNEL);
	if (!hashed_key)
		return -ENOMEM;

	ret = nvme_auth_hash_skey(hmac_id, skey,
				  skey_len, hashed_key);
	if (ret < 0)
		goto out_free_key;

	hmac_name = nvme_auth_hmac_name(hmac_id);
	if (!hmac_name) {
		pr_warn("%s: invalid hash algorithm %d\n",
			__func__, hmac_id);
		ret = -EINVAL;
		goto out_free_key;
	}

	tfm = crypto_alloc_shash(hmac_name, 0, 0);
	if (IS_ERR(tfm)) {
		ret = PTR_ERR(tfm);
		goto out_free_key;
	}

	desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
		       GFP_KERNEL);
	if (!desc) {
		ret = -ENOMEM;
		goto out_free_hash;
	}
	desc->tfm = tfm;

	ret = crypto_shash_setkey(tfm, hashed_key, hlen);
	if (ret)
		goto out_free_desc;

	ret = crypto_shash_init(desc);
	if (ret)
		goto out_free_desc;

	ret = crypto_shash_update(desc, challenge, hlen);
	if (ret)
		goto out_free_desc;

	ret = crypto_shash_final(desc, aug);
out_free_desc:
	kfree_sensitive(desc);
out_free_hash:
	crypto_free_shash(tfm);
out_free_key:
	kfree_sensitive(hashed_key);
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge);

int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, u8 dh_gid)
{
	int ret;

	ret = crypto_kpp_set_secret(dh_tfm, NULL, 0);
	if (ret)
		pr_debug("failed to set private key, error %d\n", ret);

	return ret;
}
EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey);

int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm,
		u8 *host_key, size_t host_key_len)
{
	struct kpp_request *req;
	struct crypto_wait wait;
	struct scatterlist dst;
	int ret;

	req = kpp_request_alloc(dh_tfm, GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	crypto_init_wait(&wait);
	kpp_request_set_input(req, NULL, 0);
	sg_init_one(&dst, host_key, host_key_len);
	kpp_request_set_output(req, &dst, host_key_len);
	kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
				 crypto_req_done, &wait);

	ret = crypto_wait_req(crypto_kpp_generate_public_key(req), &wait);
	kpp_request_free(req);
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey);

int 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)
{
	struct kpp_request *req;
	struct crypto_wait wait;
	struct scatterlist src, dst;
	int ret;

	req = kpp_request_alloc(dh_tfm, GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	crypto_init_wait(&wait);
	sg_init_one(&src, ctrl_key, ctrl_key_len);
	kpp_request_set_input(req, &src, ctrl_key_len);
	sg_init_one(&dst, sess_key, sess_key_len);
	kpp_request_set_output(req, &dst, sess_key_len);
	kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
				 crypto_req_done, &wait);

	ret = crypto_wait_req(crypto_kpp_compute_shared_secret(req), &wait);

	kpp_request_free(req);
	return ret;
}
EXPORT_SYMBOL_GPL(nvme_auth_gen_shared_secret);

int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key)
{
	struct nvme_dhchap_key *key;
	u8 key_hash;

	if (!secret) {
		*ret_key = NULL;
		return 0;
	}

	if (sscanf(secret, "DHHC-1:%hhd:%*s:", &key_hash) != 1)
		return -EINVAL;

	/* Pass in the secret without the 'DHHC-1:XX:' prefix */
	key = nvme_auth_extract_key(secret + 10, key_hash);
	if (IS_ERR(key)) {
		*ret_key = NULL;
		return PTR_ERR(key);
	}

	*ret_key = key;
	return 0;
}
EXPORT_SYMBOL_GPL(nvme_auth_generate_key);

MODULE_LICENSE("GPL v2");