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 <crypto/hash.h> 13#include <linux/crc32.h> 14#include <linux/base64.h> 15#include <linux/ctype.h> 16#include <linux/random.h> 17#include <linux/nvme-auth.h> 18#include <asm/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 (sscanf(secret, "DHHC-1:%hhd:%*s", &key_hash) != 1) 29 return -EINVAL; 30 if (key_hash > 3) { 31 pr_warn("Invalid DH-HMAC-CHAP hash id %d\n", 32 key_hash); 33 return -EINVAL; 34 } 35 if (key_hash > 0) { 36 /* Validate selected hash algorithm */ 37 const char *hmac = nvme_auth_hmac_name(key_hash); 38 39 if (!crypto_has_shash(hmac, 0, 0)) { 40 pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac); 41 return -ENOTSUPP; 42 } 43 } 44 dhchap_secret = kstrdup(secret, GFP_KERNEL); 45 if (!dhchap_secret) 46 return -ENOMEM; 47 if (set_ctrl) { 48 kfree(host->dhchap_ctrl_secret); 49 host->dhchap_ctrl_secret = strim(dhchap_secret); 50 host->dhchap_ctrl_key_hash = key_hash; 51 } else { 52 kfree(host->dhchap_secret); 53 host->dhchap_secret = strim(dhchap_secret); 54 host->dhchap_key_hash = key_hash; 55 } 56 return 0; 57} 58 59int nvmet_setup_dhgroup(struct nvmet_ctrl *ctrl, u8 dhgroup_id) 60{ 61 const char *dhgroup_kpp; 62 int ret = 0; 63 64 pr_debug("%s: ctrl %d selecting dhgroup %d\n", 65 __func__, ctrl->cntlid, dhgroup_id); 66 67 if (ctrl->dh_tfm) { 68 if (ctrl->dh_gid == dhgroup_id) { 69 pr_debug("%s: ctrl %d reuse existing DH group %d\n", 70 __func__, ctrl->cntlid, dhgroup_id); 71 return 0; 72 } 73 crypto_free_kpp(ctrl->dh_tfm); 74 ctrl->dh_tfm = NULL; 75 ctrl->dh_gid = 0; 76 } 77 78 if (dhgroup_id == NVME_AUTH_DHGROUP_NULL) 79 return 0; 80 81 dhgroup_kpp = nvme_auth_dhgroup_kpp(dhgroup_id); 82 if (!dhgroup_kpp) { 83 pr_debug("%s: ctrl %d invalid DH group %d\n", 84 __func__, ctrl->cntlid, dhgroup_id); 85 return -EINVAL; 86 } 87 ctrl->dh_tfm = crypto_alloc_kpp(dhgroup_kpp, 0, 0); 88 if (IS_ERR(ctrl->dh_tfm)) { 89 pr_debug("%s: ctrl %d failed to setup DH group %d, err %ld\n", 90 __func__, ctrl->cntlid, dhgroup_id, 91 PTR_ERR(ctrl->dh_tfm)); 92 ret = PTR_ERR(ctrl->dh_tfm); 93 ctrl->dh_tfm = NULL; 94 ctrl->dh_gid = 0; 95 } else { 96 ctrl->dh_gid = dhgroup_id; 97 pr_debug("%s: ctrl %d setup DH group %d\n", 98 __func__, ctrl->cntlid, ctrl->dh_gid); 99 ret = nvme_auth_gen_privkey(ctrl->dh_tfm, ctrl->dh_gid); 100 if (ret < 0) { 101 pr_debug("%s: ctrl %d failed to generate private key, err %d\n", 102 __func__, ctrl->cntlid, ret); 103 kfree_sensitive(ctrl->dh_key); 104 return ret; 105 } 106 ctrl->dh_keysize = crypto_kpp_maxsize(ctrl->dh_tfm); 107 kfree_sensitive(ctrl->dh_key); 108 ctrl->dh_key = kzalloc(ctrl->dh_keysize, GFP_KERNEL); 109 if (!ctrl->dh_key) { 110 pr_warn("ctrl %d failed to allocate public key\n", 111 ctrl->cntlid); 112 return -ENOMEM; 113 } 114 ret = nvme_auth_gen_pubkey(ctrl->dh_tfm, ctrl->dh_key, 115 ctrl->dh_keysize); 116 if (ret < 0) { 117 pr_warn("ctrl %d failed to generate public key\n", 118 ctrl->cntlid); 119 kfree(ctrl->dh_key); 120 ctrl->dh_key = NULL; 121 } 122 } 123 124 return ret; 125} 126 127int nvmet_setup_auth(struct nvmet_ctrl *ctrl) 128{ 129 int ret = 0; 130 struct nvmet_host_link *p; 131 struct nvmet_host *host = NULL; 132 const char *hash_name; 133 134 down_read(&nvmet_config_sem); 135 if (nvmet_is_disc_subsys(ctrl->subsys)) 136 goto out_unlock; 137 138 if (ctrl->subsys->allow_any_host) 139 goto out_unlock; 140 141 list_for_each_entry(p, &ctrl->subsys->hosts, entry) { 142 pr_debug("check %s\n", nvmet_host_name(p->host)); 143 if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn)) 144 continue; 145 host = p->host; 146 break; 147 } 148 if (!host) { 149 pr_debug("host %s not found\n", ctrl->hostnqn); 150 ret = -EPERM; 151 goto out_unlock; 152 } 153 154 ret = nvmet_setup_dhgroup(ctrl, host->dhchap_dhgroup_id); 155 if (ret < 0) 156 pr_warn("Failed to setup DH group"); 157 158 if (!host->dhchap_secret) { 159 pr_debug("No authentication provided\n"); 160 goto out_unlock; 161 } 162 163 if (host->dhchap_hash_id == ctrl->shash_id) { 164 pr_debug("Re-use existing hash ID %d\n", 165 ctrl->shash_id); 166 } else { 167 hash_name = nvme_auth_hmac_name(host->dhchap_hash_id); 168 if (!hash_name) { 169 pr_warn("Hash ID %d invalid\n", host->dhchap_hash_id); 170 ret = -EINVAL; 171 goto out_unlock; 172 } 173 ctrl->shash_id = host->dhchap_hash_id; 174 } 175 176 /* Skip the 'DHHC-1:XX:' prefix */ 177 nvme_auth_free_key(ctrl->host_key); 178 ctrl->host_key = nvme_auth_extract_key(host->dhchap_secret + 10, 179 host->dhchap_key_hash); 180 if (IS_ERR(ctrl->host_key)) { 181 ret = PTR_ERR(ctrl->host_key); 182 ctrl->host_key = NULL; 183 goto out_free_hash; 184 } 185 pr_debug("%s: using hash %s key %*ph\n", __func__, 186 ctrl->host_key->hash > 0 ? 187 nvme_auth_hmac_name(ctrl->host_key->hash) : "none", 188 (int)ctrl->host_key->len, ctrl->host_key->key); 189 190 nvme_auth_free_key(ctrl->ctrl_key); 191 if (!host->dhchap_ctrl_secret) { 192 ctrl->ctrl_key = NULL; 193 goto out_unlock; 194 } 195 196 ctrl->ctrl_key = nvme_auth_extract_key(host->dhchap_ctrl_secret + 10, 197 host->dhchap_ctrl_key_hash); 198 if (IS_ERR(ctrl->ctrl_key)) { 199 ret = PTR_ERR(ctrl->ctrl_key); 200 ctrl->ctrl_key = NULL; 201 goto out_free_hash; 202 } 203 pr_debug("%s: using ctrl hash %s key %*ph\n", __func__, 204 ctrl->ctrl_key->hash > 0 ? 205 nvme_auth_hmac_name(ctrl->ctrl_key->hash) : "none", 206 (int)ctrl->ctrl_key->len, ctrl->ctrl_key->key); 207 208out_free_hash: 209 if (ret) { 210 if (ctrl->host_key) { 211 nvme_auth_free_key(ctrl->host_key); 212 ctrl->host_key = NULL; 213 } 214 ctrl->shash_id = 0; 215 } 216out_unlock: 217 up_read(&nvmet_config_sem); 218 219 return ret; 220} 221 222void nvmet_auth_sq_free(struct nvmet_sq *sq) 223{ 224 cancel_delayed_work(&sq->auth_expired_work); 225 kfree(sq->dhchap_c1); 226 sq->dhchap_c1 = NULL; 227 kfree(sq->dhchap_c2); 228 sq->dhchap_c2 = NULL; 229 kfree(sq->dhchap_skey); 230 sq->dhchap_skey = NULL; 231} 232 233void nvmet_destroy_auth(struct nvmet_ctrl *ctrl) 234{ 235 ctrl->shash_id = 0; 236 237 if (ctrl->dh_tfm) { 238 crypto_free_kpp(ctrl->dh_tfm); 239 ctrl->dh_tfm = NULL; 240 ctrl->dh_gid = 0; 241 } 242 kfree_sensitive(ctrl->dh_key); 243 ctrl->dh_key = NULL; 244 245 if (ctrl->host_key) { 246 nvme_auth_free_key(ctrl->host_key); 247 ctrl->host_key = NULL; 248 } 249 if (ctrl->ctrl_key) { 250 nvme_auth_free_key(ctrl->ctrl_key); 251 ctrl->ctrl_key = NULL; 252 } 253} 254 255bool nvmet_check_auth_status(struct nvmet_req *req) 256{ 257 if (req->sq->ctrl->host_key && 258 !req->sq->authenticated) 259 return false; 260 return true; 261} 262 263int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response, 264 unsigned int shash_len) 265{ 266 struct crypto_shash *shash_tfm; 267 struct shash_desc *shash; 268 struct nvmet_ctrl *ctrl = req->sq->ctrl; 269 const char *hash_name; 270 u8 *challenge = req->sq->dhchap_c1; 271 struct nvme_dhchap_key *transformed_key; 272 u8 buf[4]; 273 int ret; 274 275 hash_name = nvme_auth_hmac_name(ctrl->shash_id); 276 if (!hash_name) { 277 pr_warn("Hash ID %d invalid\n", ctrl->shash_id); 278 return -EINVAL; 279 } 280 281 shash_tfm = crypto_alloc_shash(hash_name, 0, 0); 282 if (IS_ERR(shash_tfm)) { 283 pr_err("failed to allocate shash %s\n", hash_name); 284 return PTR_ERR(shash_tfm); 285 } 286 287 if (shash_len != crypto_shash_digestsize(shash_tfm)) { 288 pr_debug("%s: hash len mismatch (len %d digest %d)\n", 289 __func__, shash_len, 290 crypto_shash_digestsize(shash_tfm)); 291 ret = -EINVAL; 292 goto out_free_tfm; 293 } 294 295 transformed_key = nvme_auth_transform_key(ctrl->host_key, 296 ctrl->hostnqn); 297 if (IS_ERR(transformed_key)) { 298 ret = PTR_ERR(transformed_key); 299 goto out_free_tfm; 300 } 301 302 ret = crypto_shash_setkey(shash_tfm, transformed_key->key, 303 transformed_key->len); 304 if (ret) 305 goto out_free_response; 306 307 if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) { 308 challenge = kmalloc(shash_len, GFP_KERNEL); 309 if (!challenge) { 310 ret = -ENOMEM; 311 goto out_free_response; 312 } 313 ret = nvme_auth_augmented_challenge(ctrl->shash_id, 314 req->sq->dhchap_skey, 315 req->sq->dhchap_skey_len, 316 req->sq->dhchap_c1, 317 challenge, shash_len); 318 if (ret) 319 goto out_free_response; 320 } 321 322 pr_debug("ctrl %d qid %d host response seq %u transaction %d\n", 323 ctrl->cntlid, req->sq->qid, req->sq->dhchap_s1, 324 req->sq->dhchap_tid); 325 326 shash = kzalloc(sizeof(*shash) + crypto_shash_descsize(shash_tfm), 327 GFP_KERNEL); 328 if (!shash) { 329 ret = -ENOMEM; 330 goto out_free_response; 331 } 332 shash->tfm = shash_tfm; 333 ret = crypto_shash_init(shash); 334 if (ret) 335 goto out; 336 ret = crypto_shash_update(shash, challenge, shash_len); 337 if (ret) 338 goto out; 339 put_unaligned_le32(req->sq->dhchap_s1, buf); 340 ret = crypto_shash_update(shash, buf, 4); 341 if (ret) 342 goto out; 343 put_unaligned_le16(req->sq->dhchap_tid, buf); 344 ret = crypto_shash_update(shash, buf, 2); 345 if (ret) 346 goto out; 347 memset(buf, 0, 4); 348 ret = crypto_shash_update(shash, buf, 1); 349 if (ret) 350 goto out; 351 ret = crypto_shash_update(shash, "HostHost", 8); 352 if (ret) 353 goto out; 354 ret = crypto_shash_update(shash, ctrl->hostnqn, strlen(ctrl->hostnqn)); 355 if (ret) 356 goto out; 357 ret = crypto_shash_update(shash, buf, 1); 358 if (ret) 359 goto out; 360 ret = crypto_shash_update(shash, ctrl->subsysnqn, 361 strlen(ctrl->subsysnqn)); 362 if (ret) 363 goto out; 364 ret = crypto_shash_final(shash, response); 365out: 366 if (challenge != req->sq->dhchap_c1) 367 kfree(challenge); 368 kfree(shash); 369out_free_response: 370 nvme_auth_free_key(transformed_key); 371out_free_tfm: 372 crypto_free_shash(shash_tfm); 373 return 0; 374} 375 376int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response, 377 unsigned int shash_len) 378{ 379 struct crypto_shash *shash_tfm; 380 struct shash_desc *shash; 381 struct nvmet_ctrl *ctrl = req->sq->ctrl; 382 const char *hash_name; 383 u8 *challenge = req->sq->dhchap_c2; 384 struct nvme_dhchap_key *transformed_key; 385 u8 buf[4]; 386 int ret; 387 388 hash_name = nvme_auth_hmac_name(ctrl->shash_id); 389 if (!hash_name) { 390 pr_warn("Hash ID %d invalid\n", ctrl->shash_id); 391 return -EINVAL; 392 } 393 394 shash_tfm = crypto_alloc_shash(hash_name, 0, 0); 395 if (IS_ERR(shash_tfm)) { 396 pr_err("failed to allocate shash %s\n", hash_name); 397 return PTR_ERR(shash_tfm); 398 } 399 400 if (shash_len != crypto_shash_digestsize(shash_tfm)) { 401 pr_debug("%s: hash len mismatch (len %d digest %d)\n", 402 __func__, shash_len, 403 crypto_shash_digestsize(shash_tfm)); 404 ret = -EINVAL; 405 goto out_free_tfm; 406 } 407 408 transformed_key = nvme_auth_transform_key(ctrl->ctrl_key, 409 ctrl->subsysnqn); 410 if (IS_ERR(transformed_key)) { 411 ret = PTR_ERR(transformed_key); 412 goto out_free_tfm; 413 } 414 415 ret = crypto_shash_setkey(shash_tfm, transformed_key->key, 416 transformed_key->len); 417 if (ret) 418 goto out_free_response; 419 420 if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) { 421 challenge = kmalloc(shash_len, GFP_KERNEL); 422 if (!challenge) { 423 ret = -ENOMEM; 424 goto out_free_response; 425 } 426 ret = nvme_auth_augmented_challenge(ctrl->shash_id, 427 req->sq->dhchap_skey, 428 req->sq->dhchap_skey_len, 429 req->sq->dhchap_c2, 430 challenge, shash_len); 431 if (ret) 432 goto out_free_response; 433 } 434 435 shash = kzalloc(sizeof(*shash) + crypto_shash_descsize(shash_tfm), 436 GFP_KERNEL); 437 if (!shash) { 438 ret = -ENOMEM; 439 goto out_free_response; 440 } 441 shash->tfm = shash_tfm; 442 443 ret = crypto_shash_init(shash); 444 if (ret) 445 goto out; 446 ret = crypto_shash_update(shash, challenge, shash_len); 447 if (ret) 448 goto out; 449 put_unaligned_le32(req->sq->dhchap_s2, buf); 450 ret = crypto_shash_update(shash, buf, 4); 451 if (ret) 452 goto out; 453 put_unaligned_le16(req->sq->dhchap_tid, buf); 454 ret = crypto_shash_update(shash, buf, 2); 455 if (ret) 456 goto out; 457 memset(buf, 0, 4); 458 ret = crypto_shash_update(shash, buf, 1); 459 if (ret) 460 goto out; 461 ret = crypto_shash_update(shash, "Controller", 10); 462 if (ret) 463 goto out; 464 ret = crypto_shash_update(shash, ctrl->subsysnqn, 465 strlen(ctrl->subsysnqn)); 466 if (ret) 467 goto out; 468 ret = crypto_shash_update(shash, buf, 1); 469 if (ret) 470 goto out; 471 ret = crypto_shash_update(shash, ctrl->hostnqn, strlen(ctrl->hostnqn)); 472 if (ret) 473 goto out; 474 ret = crypto_shash_final(shash, response); 475out: 476 if (challenge != req->sq->dhchap_c2) 477 kfree(challenge); 478 kfree(shash); 479out_free_response: 480 nvme_auth_free_key(transformed_key); 481out_free_tfm: 482 crypto_free_shash(shash_tfm); 483 return 0; 484} 485 486int nvmet_auth_ctrl_exponential(struct nvmet_req *req, 487 u8 *buf, int buf_size) 488{ 489 struct nvmet_ctrl *ctrl = req->sq->ctrl; 490 int ret = 0; 491 492 if (!ctrl->dh_key) { 493 pr_warn("ctrl %d no DH public key!\n", ctrl->cntlid); 494 return -ENOKEY; 495 } 496 if (buf_size != ctrl->dh_keysize) { 497 pr_warn("ctrl %d DH public key size mismatch, need %zu is %d\n", 498 ctrl->cntlid, ctrl->dh_keysize, buf_size); 499 ret = -EINVAL; 500 } else { 501 memcpy(buf, ctrl->dh_key, buf_size); 502 pr_debug("%s: ctrl %d public key %*ph\n", __func__, 503 ctrl->cntlid, (int)buf_size, buf); 504 } 505 506 return ret; 507} 508 509int nvmet_auth_ctrl_sesskey(struct nvmet_req *req, 510 u8 *pkey, int pkey_size) 511{ 512 struct nvmet_ctrl *ctrl = req->sq->ctrl; 513 int ret; 514 515 req->sq->dhchap_skey_len = ctrl->dh_keysize; 516 req->sq->dhchap_skey = kzalloc(req->sq->dhchap_skey_len, GFP_KERNEL); 517 if (!req->sq->dhchap_skey) 518 return -ENOMEM; 519 ret = nvme_auth_gen_shared_secret(ctrl->dh_tfm, 520 pkey, pkey_size, 521 req->sq->dhchap_skey, 522 req->sq->dhchap_skey_len); 523 if (ret) 524 pr_debug("failed to compute shared secret, err %d\n", ret); 525 else 526 pr_debug("%s: shared secret %*ph\n", __func__, 527 (int)req->sq->dhchap_skey_len, 528 req->sq->dhchap_skey); 529 530 return ret; 531} 532