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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <libcryptsetup.h>
#include "cryptsetup-token-util.h"
#include "hexdecoct.h"
#include "json.h"
#include "luks2-fido2.h"
#include "memory-util.h"
#include "strv.h"
int acquire_luks2_key(
struct crypt_device *cd,
const char *json,
const char *device,
const char *pin,
char **ret_keyslot_passphrase,
size_t *ret_keyslot_passphrase_size) {
int r;
Fido2EnrollFlags required;
size_t cid_size, salt_size, decrypted_key_size;
_cleanup_free_ void *cid = NULL, *salt = NULL;
_cleanup_free_ char *rp_id = NULL;
_cleanup_(erase_and_freep) void *decrypted_key = NULL;
_cleanup_(erase_and_freep) char *base64_encoded = NULL;
_cleanup_strv_free_erase_ char **pins = NULL;
ssize_t base64_encoded_size;
assert(ret_keyslot_passphrase);
assert(ret_keyslot_passphrase_size);
r = parse_luks2_fido2_data(cd, json, &rp_id, &salt, &salt_size, &cid, &cid_size, &required);
if (r < 0)
return r;
if (pin) {
pins = strv_new(pin);
if (!pins)
return crypt_log_oom(cd);
}
/* configured to use pin but none was provided */
if ((required & FIDO2ENROLL_PIN) && strv_isempty(pins))
return -ENOANO;
r = fido2_use_hmac_hash(
device,
rp_id ?: "io.systemd.cryptsetup",
salt, salt_size,
cid, cid_size,
pins,
required,
&decrypted_key,
&decrypted_key_size);
if (r == -ENOLCK) /* libcryptsetup returns -ENOANO also on wrong PIN */
r = -ENOANO;
if (r < 0)
return r;
/* Before using this key as passphrase we base64 encode it, for compat with homed */
base64_encoded_size = base64mem(decrypted_key, decrypted_key_size, &base64_encoded);
if (base64_encoded_size < 0)
return crypt_log_error_errno(cd, (int) base64_encoded_size, "Failed to base64 encode key: %m");
*ret_keyslot_passphrase = TAKE_PTR(base64_encoded);
*ret_keyslot_passphrase_size = base64_encoded_size;
return 0;
}
/* this function expects valid "systemd-fido2" in json */
int parse_luks2_fido2_data(
struct crypt_device *cd,
const char *json,
char **ret_rp_id,
void **ret_salt,
size_t *ret_salt_size,
void **ret_cid,
size_t *ret_cid_size,
Fido2EnrollFlags *ret_required) {
_cleanup_free_ void *cid = NULL, *salt = NULL;
size_t cid_size = 0, salt_size = 0;
_cleanup_free_ char *rp = NULL;
int r;
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
JsonVariant *w;
Fido2EnrollFlags required = 0;
assert(json);
assert(ret_rp_id);
assert(ret_salt);
assert(ret_salt_size);
assert(ret_cid);
assert(ret_cid_size);
assert(ret_required);
r = json_parse(json, 0, &v, NULL, NULL);
if (r < 0)
return crypt_log_error_errno(cd, r, "Failed to parse JSON token data: %m");
w = json_variant_by_key(v, "fido2-credential");
if (!w)
return -EINVAL;
r = unbase64mem(json_variant_string(w), SIZE_MAX, &cid, &cid_size);
if (r < 0)
return crypt_log_error_errno(cd, r, "Failed to parse 'fido2-credentials' field: %m");
w = json_variant_by_key(v, "fido2-salt");
if (!w)
return -EINVAL;
r = unbase64mem(json_variant_string(w), SIZE_MAX, &salt, &salt_size);
if (r < 0)
return crypt_log_error_errno(cd, r, "Failed to parse 'fido2-salt' field: %m");
w = json_variant_by_key(v, "fido2-rp");
if (w) {
/* The "rp" field is optional. */
rp = strdup(json_variant_string(w));
if (!rp) {
crypt_log_error(cd, "Not enough memory.");
return -ENOMEM;
}
}
w = json_variant_by_key(v, "fido2-clientPin-required");
if (w)
/* The "fido2-clientPin-required" field is optional. */
SET_FLAG(required, FIDO2ENROLL_PIN, json_variant_boolean(w));
else
required |= FIDO2ENROLL_PIN_IF_NEEDED; /* compat with 248, where the field was unset */
w = json_variant_by_key(v, "fido2-up-required");
if (w)
/* The "fido2-up-required" field is optional. */
SET_FLAG(required, FIDO2ENROLL_UP, json_variant_boolean(w));
else
required |= FIDO2ENROLL_UP_IF_NEEDED; /* compat with 248 */
w = json_variant_by_key(v, "fido2-uv-required");
if (w)
/* The "fido2-uv-required" field is optional. */
SET_FLAG(required, FIDO2ENROLL_UV, json_variant_boolean(w));
else
required |= FIDO2ENROLL_UV_OMIT; /* compat with 248 */
*ret_rp_id = TAKE_PTR(rp);
*ret_cid = TAKE_PTR(cid);
*ret_cid_size = cid_size;
*ret_salt = TAKE_PTR(salt);
*ret_salt_size = salt_size;
*ret_required = required;
return 0;
}
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