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 17 static u32 nvme_dhchap_seqnum; 18 static DEFINE_MUTEX(nvme_dhchap_mutex); 19 20 u32 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 } 36 EXPORT_SYMBOL_GPL(nvme_auth_get_seqnum); 37 38 static 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 56 const 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 } 62 EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_name); 63 64 const 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 } 70 EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_kpp); 71 72 u8 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 } 87 EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_id); 88 89 static 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 }; 110 111 const 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 } 117 EXPORT_SYMBOL_GPL(nvme_auth_hmac_name); 118 119 const 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 } 125 EXPORT_SYMBOL_GPL(nvme_auth_digest_name); 126 127 u8 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 } 143 EXPORT_SYMBOL_GPL(nvme_auth_hmac_id); 144 145 size_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 } 151 EXPORT_SYMBOL_GPL(nvme_auth_hmac_hash_len); 152 153 u32 nvme_auth_key_struct_size(u32 key_len) 154 { 155 struct nvme_dhchap_key key; 156 157 return struct_size(&key, key, key_len); 158 } 159 EXPORT_SYMBOL_GPL(nvme_auth_key_struct_size); 160 161 struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret, 162 u8 key_hash) 163 { 164 struct nvme_dhchap_key *key; 165 unsigned char *p; 166 u32 crc; 167 int ret, key_len; 168 size_t allocated_len = strlen(secret); 169 170 /* Secret might be affixed with a ':' */ 171 p = strrchr(secret, ':'); 172 if (p) 173 allocated_len = p - secret; 174 key = nvme_auth_alloc_key(allocated_len, 0); 175 if (!key) 176 return ERR_PTR(-ENOMEM); 177 178 key_len = base64_decode(secret, allocated_len, key->key); 179 if (key_len < 0) { 180 pr_debug("base64 key decoding error %d\n", 181 key_len); 182 ret = key_len; 183 goto out_free_secret; 184 } 185 186 if (key_len != 36 && key_len != 52 && 187 key_len != 68) { 188 pr_err("Invalid key len %d\n", key_len); 189 ret = -EINVAL; 190 goto out_free_secret; 191 } 192 193 if (key_hash > 0 && 194 (key_len - 4) != nvme_auth_hmac_hash_len(key_hash)) { 195 pr_err("Mismatched key len %d for %s\n", key_len, 196 nvme_auth_hmac_name(key_hash)); 197 ret = -EINVAL; 198 goto out_free_secret; 199 } 200 201 /* The last four bytes is the CRC in little-endian format */ 202 key_len -= 4; 203 /* 204 * The linux implementation doesn't do pre- and post-increments, 205 * so we have to do it manually. 206 */ 207 crc = ~crc32(~0, key->key, key_len); 208 209 if (get_unaligned_le32(key->key + key_len) != crc) { 210 pr_err("key crc mismatch (key %08x, crc %08x)\n", 211 get_unaligned_le32(key->key + key_len), crc); 212 ret = -EKEYREJECTED; 213 goto out_free_secret; 214 } 215 key->len = key_len; 216 key->hash = key_hash; 217 return key; 218 out_free_secret: 219 nvme_auth_free_key(key); 220 return ERR_PTR(ret); 221 } 222 EXPORT_SYMBOL_GPL(nvme_auth_extract_key); 223 224 struct nvme_dhchap_key *nvme_auth_alloc_key(u32 len, u8 hash) 225 { 226 u32 num_bytes = nvme_auth_key_struct_size(len); 227 struct nvme_dhchap_key *key = kzalloc(num_bytes, GFP_KERNEL); 228 229 if (key) { 230 key->len = len; 231 key->hash = hash; 232 } 233 return key; 234 } 235 EXPORT_SYMBOL_GPL(nvme_auth_alloc_key); 236 237 void nvme_auth_free_key(struct nvme_dhchap_key *key) 238 { 239 if (!key) 240 return; 241 kfree_sensitive(key); 242 } 243 EXPORT_SYMBOL_GPL(nvme_auth_free_key); 244 245 u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn) 246 { 247 const char *hmac_name; 248 struct crypto_shash *key_tfm; 249 struct shash_desc *shash; 250 u8 *transformed_key; 251 int ret; 252 253 if (!key) { 254 pr_warn("No key specified\n"); 255 return ERR_PTR(-ENOKEY); 256 } 257 if (key->hash == 0) { 258 transformed_key = kmemdup(key->key, key->len, GFP_KERNEL); 259 return transformed_key ? transformed_key : ERR_PTR(-ENOMEM); 260 } 261 hmac_name = nvme_auth_hmac_name(key->hash); 262 if (!hmac_name) { 263 pr_warn("Invalid key hash id %d\n", key->hash); 264 return ERR_PTR(-EINVAL); 265 } 266 267 key_tfm = crypto_alloc_shash(hmac_name, 0, 0); 268 if (IS_ERR(key_tfm)) 269 return (u8 *)key_tfm; 270 271 shash = kmalloc(sizeof(struct shash_desc) + 272 crypto_shash_descsize(key_tfm), 273 GFP_KERNEL); 274 if (!shash) { 275 ret = -ENOMEM; 276 goto out_free_key; 277 } 278 279 transformed_key = kzalloc(crypto_shash_digestsize(key_tfm), GFP_KERNEL); 280 if (!transformed_key) { 281 ret = -ENOMEM; 282 goto out_free_shash; 283 } 284 285 shash->tfm = key_tfm; 286 ret = crypto_shash_setkey(key_tfm, key->key, key->len); 287 if (ret < 0) 288 goto out_free_transformed_key; 289 ret = crypto_shash_init(shash); 290 if (ret < 0) 291 goto out_free_transformed_key; 292 ret = crypto_shash_update(shash, nqn, strlen(nqn)); 293 if (ret < 0) 294 goto out_free_transformed_key; 295 ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17); 296 if (ret < 0) 297 goto out_free_transformed_key; 298 ret = crypto_shash_final(shash, transformed_key); 299 if (ret < 0) 300 goto out_free_transformed_key; 301 302 kfree(shash); 303 crypto_free_shash(key_tfm); 304 305 return transformed_key; 306 307 out_free_transformed_key: 308 kfree_sensitive(transformed_key); 309 out_free_shash: 310 kfree(shash); 311 out_free_key: 312 crypto_free_shash(key_tfm); 313 314 return ERR_PTR(ret); 315 } 316 EXPORT_SYMBOL_GPL(nvme_auth_transform_key); 317 318 static int nvme_auth_hash_skey(int hmac_id, u8 *skey, size_t skey_len, u8 *hkey) 319 { 320 const char *digest_name; 321 struct crypto_shash *tfm; 322 int ret; 323 324 digest_name = nvme_auth_digest_name(hmac_id); 325 if (!digest_name) { 326 pr_debug("%s: failed to get digest for %d\n", __func__, 327 hmac_id); 328 return -EINVAL; 329 } 330 tfm = crypto_alloc_shash(digest_name, 0, 0); 331 if (IS_ERR(tfm)) 332 return -ENOMEM; 333 334 ret = crypto_shash_tfm_digest(tfm, skey, skey_len, hkey); 335 if (ret < 0) 336 pr_debug("%s: Failed to hash digest len %zu\n", __func__, 337 skey_len); 338 339 crypto_free_shash(tfm); 340 return ret; 341 } 342 343 int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len, 344 u8 *challenge, u8 *aug, size_t hlen) 345 { 346 struct crypto_shash *tfm; 347 struct shash_desc *desc; 348 u8 *hashed_key; 349 const char *hmac_name; 350 int ret; 351 352 hashed_key = kmalloc(hlen, GFP_KERNEL); 353 if (!hashed_key) 354 return -ENOMEM; 355 356 ret = nvme_auth_hash_skey(hmac_id, skey, 357 skey_len, hashed_key); 358 if (ret < 0) 359 goto out_free_key; 360 361 hmac_name = nvme_auth_hmac_name(hmac_id); 362 if (!hmac_name) { 363 pr_warn("%s: invalid hash algorithm %d\n", 364 __func__, hmac_id); 365 ret = -EINVAL; 366 goto out_free_key; 367 } 368 369 tfm = crypto_alloc_shash(hmac_name, 0, 0); 370 if (IS_ERR(tfm)) { 371 ret = PTR_ERR(tfm); 372 goto out_free_key; 373 } 374 375 desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), 376 GFP_KERNEL); 377 if (!desc) { 378 ret = -ENOMEM; 379 goto out_free_hash; 380 } 381 desc->tfm = tfm; 382 383 ret = crypto_shash_setkey(tfm, hashed_key, hlen); 384 if (ret) 385 goto out_free_desc; 386 387 ret = crypto_shash_init(desc); 388 if (ret) 389 goto out_free_desc; 390 391 ret = crypto_shash_update(desc, challenge, hlen); 392 if (ret) 393 goto out_free_desc; 394 395 ret = crypto_shash_final(desc, aug); 396 out_free_desc: 397 kfree_sensitive(desc); 398 out_free_hash: 399 crypto_free_shash(tfm); 400 out_free_key: 401 kfree_sensitive(hashed_key); 402 return ret; 403 } 404 EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge); 405 406 int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, u8 dh_gid) 407 { 408 int ret; 409 410 ret = crypto_kpp_set_secret(dh_tfm, NULL, 0); 411 if (ret) 412 pr_debug("failed to set private key, error %d\n", ret); 413 414 return ret; 415 } 416 EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey); 417 418 int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm, 419 u8 *host_key, size_t host_key_len) 420 { 421 struct kpp_request *req; 422 struct crypto_wait wait; 423 struct scatterlist dst; 424 int ret; 425 426 req = kpp_request_alloc(dh_tfm, GFP_KERNEL); 427 if (!req) 428 return -ENOMEM; 429 430 crypto_init_wait(&wait); 431 kpp_request_set_input(req, NULL, 0); 432 sg_init_one(&dst, host_key, host_key_len); 433 kpp_request_set_output(req, &dst, host_key_len); 434 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, 435 crypto_req_done, &wait); 436 437 ret = crypto_wait_req(crypto_kpp_generate_public_key(req), &wait); 438 kpp_request_free(req); 439 return ret; 440 } 441 EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey); 442 443 int nvme_auth_gen_shared_secret(struct crypto_kpp *dh_tfm, 444 u8 *ctrl_key, size_t ctrl_key_len, 445 u8 *sess_key, size_t sess_key_len) 446 { 447 struct kpp_request *req; 448 struct crypto_wait wait; 449 struct scatterlist src, dst; 450 int ret; 451 452 req = kpp_request_alloc(dh_tfm, GFP_KERNEL); 453 if (!req) 454 return -ENOMEM; 455 456 crypto_init_wait(&wait); 457 sg_init_one(&src, ctrl_key, ctrl_key_len); 458 kpp_request_set_input(req, &src, ctrl_key_len); 459 sg_init_one(&dst, sess_key, sess_key_len); 460 kpp_request_set_output(req, &dst, sess_key_len); 461 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, 462 crypto_req_done, &wait); 463 464 ret = crypto_wait_req(crypto_kpp_compute_shared_secret(req), &wait); 465 466 kpp_request_free(req); 467 return ret; 468 } 469 EXPORT_SYMBOL_GPL(nvme_auth_gen_shared_secret); 470 471 int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key) 472 { 473 struct nvme_dhchap_key *key; 474 u8 key_hash; 475 476 if (!secret) { 477 *ret_key = NULL; 478 return 0; 479 } 480 481 if (sscanf(secret, "DHHC-1:%hhd:%*s:", &key_hash) != 1) 482 return -EINVAL; 483 484 /* Pass in the secret without the 'DHHC-1:XX:' prefix */ 485 key = nvme_auth_extract_key(secret + 10, key_hash); 486 if (IS_ERR(key)) { 487 *ret_key = NULL; 488 return PTR_ERR(key); 489 } 490 491 *ret_key = key; 492 return 0; 493 } 494 EXPORT_SYMBOL_GPL(nvme_auth_generate_key); 495 496 MODULE_LICENSE("GPL v2"); 497