/* * LUKS - Linux Unified Key Setup v2, PBKDF2 digest handler (LUKS1 compatible) * * Copyright (C) 2015-2021 Red Hat, Inc. All rights reserved. * Copyright (C) 2015-2021 Milan Broz * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "luks2_internal.h" #define LUKS_DIGESTSIZE 20 // since SHA1 #define LUKS_SALTSIZE 32 #define LUKS_MKD_ITERATIONS_MS 125 static int PBKDF2_digest_verify(struct crypt_device *cd, int digest, const char *volume_key, size_t volume_key_len) { char checkHashBuf[64]; json_object *jobj_digest, *jobj1; const char *hashSpec; char *mkDigest = NULL, mkDigestSalt[LUKS_SALTSIZE]; unsigned int mkDigestIterations; size_t len; int r; /* This can be done only for internally linked digests */ jobj_digest = LUKS2_get_digest_jobj(crypt_get_hdr(cd, CRYPT_LUKS2), digest); if (!jobj_digest) return -EINVAL; if (!json_object_object_get_ex(jobj_digest, "hash", &jobj1)) return -EINVAL; hashSpec = json_object_get_string(jobj1); if (!json_object_object_get_ex(jobj_digest, "iterations", &jobj1)) return -EINVAL; mkDigestIterations = json_object_get_int64(jobj1); if (!json_object_object_get_ex(jobj_digest, "salt", &jobj1)) return -EINVAL; len = sizeof(mkDigestSalt); if (!base64_decode(json_object_get_string(jobj1), json_object_get_string_len(jobj1), mkDigestSalt, &len)) return -EINVAL; if (len != LUKS_SALTSIZE) return -EINVAL; if (!json_object_object_get_ex(jobj_digest, "digest", &jobj1)) return -EINVAL; len = 0; if (!base64_decode_alloc(json_object_get_string(jobj1), json_object_get_string_len(jobj1), &mkDigest, &len)) return -EINVAL; if (len < LUKS_DIGESTSIZE || len > sizeof(checkHashBuf) || (len != LUKS_DIGESTSIZE && len != (size_t)crypt_hash_size(hashSpec))) { free(mkDigest); return -EINVAL; } r = -EPERM; if (crypt_pbkdf(CRYPT_KDF_PBKDF2, hashSpec, volume_key, volume_key_len, mkDigestSalt, LUKS_SALTSIZE, checkHashBuf, len, mkDigestIterations, 0, 0) < 0) { r = -EINVAL; } else { if (memcmp(checkHashBuf, mkDigest, len) == 0) r = 0; } free(mkDigest); return r; } static int PBKDF2_digest_store(struct crypt_device *cd, int digest, const char *volume_key, size_t volume_key_len) { json_object *jobj_digest, *jobj_digests; char salt[LUKS_SALTSIZE], digest_raw[128]; int hmac_size, r; char *base64_str; struct luks2_hdr *hdr; struct crypt_pbkdf_limits pbkdf_limits; const struct crypt_pbkdf_type *pbkdf_cd; struct crypt_pbkdf_type pbkdf = { .type = CRYPT_KDF_PBKDF2, .time_ms = LUKS_MKD_ITERATIONS_MS, }; /* Inherit hash from PBKDF setting */ pbkdf_cd = crypt_get_pbkdf_type(cd); if (pbkdf_cd) pbkdf.hash = pbkdf_cd->hash; if (!pbkdf.hash) pbkdf.hash = DEFAULT_LUKS1_HASH; log_dbg(cd, "Setting PBKDF2 type key digest %d.", digest); r = crypt_random_get(cd, salt, LUKS_SALTSIZE, CRYPT_RND_SALT); if (r < 0) return r; r = crypt_pbkdf_get_limits(CRYPT_KDF_PBKDF2, &pbkdf_limits); if (r < 0) return r; if (crypt_get_pbkdf(cd)->flags & CRYPT_PBKDF_NO_BENCHMARK) pbkdf.iterations = pbkdf_limits.min_iterations; else { r = crypt_benchmark_pbkdf_internal(cd, &pbkdf, volume_key_len); if (r < 0) return r; } hmac_size = crypt_hmac_size(pbkdf.hash); if (hmac_size < 0 || hmac_size > (int)sizeof(digest_raw)) return -EINVAL; r = crypt_pbkdf(CRYPT_KDF_PBKDF2, pbkdf.hash, volume_key, volume_key_len, salt, LUKS_SALTSIZE, digest_raw, hmac_size, pbkdf.iterations, 0, 0); if (r < 0) return r; jobj_digest = LUKS2_get_digest_jobj(crypt_get_hdr(cd, CRYPT_LUKS2), digest); jobj_digests = NULL; if (!jobj_digest) { hdr = crypt_get_hdr(cd, CRYPT_LUKS2); jobj_digest = json_object_new_object(); json_object_object_get_ex(hdr->jobj, "digests", &jobj_digests); } json_object_object_add(jobj_digest, "type", json_object_new_string("pbkdf2")); json_object_object_add(jobj_digest, "keyslots", json_object_new_array()); json_object_object_add(jobj_digest, "segments", json_object_new_array()); json_object_object_add(jobj_digest, "hash", json_object_new_string(pbkdf.hash)); json_object_object_add(jobj_digest, "iterations", json_object_new_int(pbkdf.iterations)); base64_encode_alloc(salt, LUKS_SALTSIZE, &base64_str); if (!base64_str) { json_object_put(jobj_digest); return -ENOMEM; } json_object_object_add(jobj_digest, "salt", json_object_new_string(base64_str)); free(base64_str); base64_encode_alloc(digest_raw, hmac_size, &base64_str); if (!base64_str) { json_object_put(jobj_digest); return -ENOMEM; } json_object_object_add(jobj_digest, "digest", json_object_new_string(base64_str)); free(base64_str); if (jobj_digests) json_object_object_add_by_uint(jobj_digests, digest, jobj_digest); JSON_DBG(cd, jobj_digest, "Digest JSON:"); return 0; } static int PBKDF2_digest_dump(struct crypt_device *cd, int digest) { json_object *jobj_digest, *jobj1; /* This can be done only for internally linked digests */ jobj_digest = LUKS2_get_digest_jobj(crypt_get_hdr(cd, CRYPT_LUKS2), digest); if (!jobj_digest) return -EINVAL; json_object_object_get_ex(jobj_digest, "hash", &jobj1); log_std(cd, "\tHash: %s\n", json_object_get_string(jobj1)); json_object_object_get_ex(jobj_digest, "iterations", &jobj1); log_std(cd, "\tIterations: %" PRIu64 "\n", json_object_get_int64(jobj1)); json_object_object_get_ex(jobj_digest, "salt", &jobj1); log_std(cd, "\tSalt: "); hexprint_base64(cd, jobj1, " ", " "); json_object_object_get_ex(jobj_digest, "digest", &jobj1); log_std(cd, "\tDigest: "); hexprint_base64(cd, jobj1, " ", " "); return 0; } const digest_handler PBKDF2_digest = { .name = "pbkdf2", .verify = PBKDF2_digest_verify, .store = PBKDF2_digest_store, .dump = PBKDF2_digest_dump, };