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/*
* 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,
};
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