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 /* The last four bytes is the CRC in little-endian format */ 194 key_len -= 4; 195 /* 196 * The linux implementation doesn't do pre- and post-increments, 197 * so we have to do it manually. 198 */ 199 crc = ~crc32(~0, key->key, key_len); 200 201 if (get_unaligned_le32(key->key + key_len) != crc) { 202 pr_err("key crc mismatch (key %08x, crc %08x)\n", 203 get_unaligned_le32(key->key + key_len), crc); 204 ret = -EKEYREJECTED; 205 goto out_free_secret; 206 } 207 key->len = key_len; 208 key->hash = key_hash; 209 return key; 210 out_free_secret: 211 nvme_auth_free_key(key); 212 return ERR_PTR(ret); 213 } 214 EXPORT_SYMBOL_GPL(nvme_auth_extract_key); 215 216 struct nvme_dhchap_key *nvme_auth_alloc_key(u32 len, u8 hash) 217 { 218 u32 num_bytes = nvme_auth_key_struct_size(len); 219 struct nvme_dhchap_key *key = kzalloc(num_bytes, GFP_KERNEL); 220 221 if (key) { 222 key->len = len; 223 key->hash = hash; 224 } 225 return key; 226 } 227 EXPORT_SYMBOL_GPL(nvme_auth_alloc_key); 228 229 void nvme_auth_free_key(struct nvme_dhchap_key *key) 230 { 231 if (!key) 232 return; 233 kfree_sensitive(key); 234 } 235 EXPORT_SYMBOL_GPL(nvme_auth_free_key); 236 237 struct nvme_dhchap_key *nvme_auth_transform_key( 238 struct nvme_dhchap_key *key, char *nqn) 239 { 240 const char *hmac_name; 241 struct crypto_shash *key_tfm; 242 struct shash_desc *shash; 243 struct nvme_dhchap_key *transformed_key; 244 int ret, key_len; 245 246 if (!key) { 247 pr_warn("No key specified\n"); 248 return ERR_PTR(-ENOKEY); 249 } 250 if (key->hash == 0) { 251 key_len = nvme_auth_key_struct_size(key->len); 252 transformed_key = kmemdup(key, key_len, GFP_KERNEL); 253 if (!transformed_key) 254 return ERR_PTR(-ENOMEM); 255 return transformed_key; 256 } 257 hmac_name = nvme_auth_hmac_name(key->hash); 258 if (!hmac_name) { 259 pr_warn("Invalid key hash id %d\n", key->hash); 260 return ERR_PTR(-EINVAL); 261 } 262 263 key_tfm = crypto_alloc_shash(hmac_name, 0, 0); 264 if (IS_ERR(key_tfm)) 265 return ERR_CAST(key_tfm); 266 267 shash = kmalloc(sizeof(struct shash_desc) + 268 crypto_shash_descsize(key_tfm), 269 GFP_KERNEL); 270 if (!shash) { 271 ret = -ENOMEM; 272 goto out_free_key; 273 } 274 275 key_len = crypto_shash_digestsize(key_tfm); 276 transformed_key = nvme_auth_alloc_key(key_len, key->hash); 277 if (!transformed_key) { 278 ret = -ENOMEM; 279 goto out_free_shash; 280 } 281 282 shash->tfm = key_tfm; 283 ret = crypto_shash_setkey(key_tfm, key->key, key->len); 284 if (ret < 0) 285 goto out_free_transformed_key; 286 ret = crypto_shash_init(shash); 287 if (ret < 0) 288 goto out_free_transformed_key; 289 ret = crypto_shash_update(shash, nqn, strlen(nqn)); 290 if (ret < 0) 291 goto out_free_transformed_key; 292 ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17); 293 if (ret < 0) 294 goto out_free_transformed_key; 295 ret = crypto_shash_final(shash, transformed_key->key); 296 if (ret < 0) 297 goto out_free_transformed_key; 298 299 kfree(shash); 300 crypto_free_shash(key_tfm); 301 302 return transformed_key; 303 304 out_free_transformed_key: 305 nvme_auth_free_key(transformed_key); 306 out_free_shash: 307 kfree(shash); 308 out_free_key: 309 crypto_free_shash(key_tfm); 310 311 return ERR_PTR(ret); 312 } 313 EXPORT_SYMBOL_GPL(nvme_auth_transform_key); 314 315 static int nvme_auth_hash_skey(int hmac_id, u8 *skey, size_t skey_len, u8 *hkey) 316 { 317 const char *digest_name; 318 struct crypto_shash *tfm; 319 int ret; 320 321 digest_name = nvme_auth_digest_name(hmac_id); 322 if (!digest_name) { 323 pr_debug("%s: failed to get digest for %d\n", __func__, 324 hmac_id); 325 return -EINVAL; 326 } 327 tfm = crypto_alloc_shash(digest_name, 0, 0); 328 if (IS_ERR(tfm)) 329 return -ENOMEM; 330 331 ret = crypto_shash_tfm_digest(tfm, skey, skey_len, hkey); 332 if (ret < 0) 333 pr_debug("%s: Failed to hash digest len %zu\n", __func__, 334 skey_len); 335 336 crypto_free_shash(tfm); 337 return ret; 338 } 339 340 int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len, 341 u8 *challenge, u8 *aug, size_t hlen) 342 { 343 struct crypto_shash *tfm; 344 u8 *hashed_key; 345 const char *hmac_name; 346 int ret; 347 348 hashed_key = kmalloc(hlen, GFP_KERNEL); 349 if (!hashed_key) 350 return -ENOMEM; 351 352 ret = nvme_auth_hash_skey(hmac_id, skey, 353 skey_len, hashed_key); 354 if (ret < 0) 355 goto out_free_key; 356 357 hmac_name = nvme_auth_hmac_name(hmac_id); 358 if (!hmac_name) { 359 pr_warn("%s: invalid hash algorithm %d\n", 360 __func__, hmac_id); 361 ret = -EINVAL; 362 goto out_free_key; 363 } 364 365 tfm = crypto_alloc_shash(hmac_name, 0, 0); 366 if (IS_ERR(tfm)) { 367 ret = PTR_ERR(tfm); 368 goto out_free_key; 369 } 370 371 ret = crypto_shash_setkey(tfm, hashed_key, hlen); 372 if (ret) 373 goto out_free_hash; 374 375 ret = crypto_shash_tfm_digest(tfm, challenge, hlen, aug); 376 out_free_hash: 377 crypto_free_shash(tfm); 378 out_free_key: 379 kfree_sensitive(hashed_key); 380 return ret; 381 } 382 EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge); 383 384 int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, u8 dh_gid) 385 { 386 int ret; 387 388 ret = crypto_kpp_set_secret(dh_tfm, NULL, 0); 389 if (ret) 390 pr_debug("failed to set private key, error %d\n", ret); 391 392 return ret; 393 } 394 EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey); 395 396 int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm, 397 u8 *host_key, size_t host_key_len) 398 { 399 struct kpp_request *req; 400 struct crypto_wait wait; 401 struct scatterlist dst; 402 int ret; 403 404 req = kpp_request_alloc(dh_tfm, GFP_KERNEL); 405 if (!req) 406 return -ENOMEM; 407 408 crypto_init_wait(&wait); 409 kpp_request_set_input(req, NULL, 0); 410 sg_init_one(&dst, host_key, host_key_len); 411 kpp_request_set_output(req, &dst, host_key_len); 412 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, 413 crypto_req_done, &wait); 414 415 ret = crypto_wait_req(crypto_kpp_generate_public_key(req), &wait); 416 kpp_request_free(req); 417 return ret; 418 } 419 EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey); 420 421 int nvme_auth_gen_shared_secret(struct crypto_kpp *dh_tfm, 422 u8 *ctrl_key, size_t ctrl_key_len, 423 u8 *sess_key, size_t sess_key_len) 424 { 425 struct kpp_request *req; 426 struct crypto_wait wait; 427 struct scatterlist src, dst; 428 int ret; 429 430 req = kpp_request_alloc(dh_tfm, GFP_KERNEL); 431 if (!req) 432 return -ENOMEM; 433 434 crypto_init_wait(&wait); 435 sg_init_one(&src, ctrl_key, ctrl_key_len); 436 kpp_request_set_input(req, &src, ctrl_key_len); 437 sg_init_one(&dst, sess_key, sess_key_len); 438 kpp_request_set_output(req, &dst, sess_key_len); 439 kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, 440 crypto_req_done, &wait); 441 442 ret = crypto_wait_req(crypto_kpp_compute_shared_secret(req), &wait); 443 444 kpp_request_free(req); 445 return ret; 446 } 447 EXPORT_SYMBOL_GPL(nvme_auth_gen_shared_secret); 448 449 int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key) 450 { 451 struct nvme_dhchap_key *key; 452 u8 key_hash; 453 454 if (!secret) { 455 *ret_key = NULL; 456 return 0; 457 } 458 459 if (sscanf(secret, "DHHC-1:%hhd:%*s:", &key_hash) != 1) 460 return -EINVAL; 461 462 /* Pass in the secret without the 'DHHC-1:XX:' prefix */ 463 key = nvme_auth_extract_key(secret + 10, key_hash); 464 if (IS_ERR(key)) { 465 *ret_key = NULL; 466 return PTR_ERR(key); 467 } 468 469 *ret_key = key; 470 return 0; 471 } 472 EXPORT_SYMBOL_GPL(nvme_auth_generate_key); 473 474 MODULE_LICENSE("GPL v2"); 475