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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "ask-password-api.h"
#include "cryptsetup-fido2.h"
#include "fileio.h"
#include "hexdecoct.h"
#include "json.h"
#include "libfido2-util.h"
#include "parse-util.h"
#include "random-util.h"
#include "strv.h"
int acquire_fido2_key(
const char *volume_name,
const char *friendly_name,
const char *device,
const char *rp_id,
const void *cid,
size_t cid_size,
const char *key_file,
size_t key_file_size,
uint64_t key_file_offset,
const void *key_data,
size_t key_data_size,
usec_t until,
bool headless,
void **ret_decrypted_key,
size_t *ret_decrypted_key_size) {
AskPasswordFlags flags = ASK_PASSWORD_PUSH_CACHE | ASK_PASSWORD_ACCEPT_CACHED;
_cleanup_strv_free_erase_ char **pins = NULL;
_cleanup_free_ void *loaded_salt = NULL;
const char *salt;
size_t salt_size;
char *e;
int r;
assert(cid);
assert(key_file || key_data);
if (key_data) {
salt = key_data;
salt_size = key_data_size;
} else {
_cleanup_free_ char *bindname = NULL;
/* If we read the salt via AF_UNIX, make this client recognizable */
if (asprintf(&bindname, "@%" PRIx64"/cryptsetup-fido2/%s", random_u64(), volume_name) < 0)
return log_oom();
r = read_full_file_full(
AT_FDCWD, key_file,
key_file_offset == 0 ? UINT64_MAX : key_file_offset,
key_file_size == 0 ? SIZE_MAX : key_file_size,
READ_FULL_FILE_CONNECT_SOCKET,
bindname,
(char**) &loaded_salt, &salt_size);
if (r < 0)
return r;
salt = loaded_salt;
}
e = getenv("PIN");
if (e) {
pins = strv_new(e);
if (!pins)
return log_oom();
string_erase(e);
if (unsetenv("PIN") < 0)
return log_error_errno(errno, "Failed to unset $PIN: %m");
}
for (;;) {
r = fido2_use_hmac_hash(
device,
rp_id ?: "io.systemd.cryptsetup",
salt, salt_size,
cid, cid_size,
pins,
/* up= */ true,
ret_decrypted_key,
ret_decrypted_key_size);
if (!IN_SET(r,
-ENOANO, /* needs pin */
-ENOLCK)) /* pin incorrect */
return r;
pins = strv_free_erase(pins);
if (headless)
return log_error_errno(SYNTHETIC_ERRNO(ENOPKG), "PIN querying disabled via 'headless' option. Use the '$PIN' environment variable.");
r = ask_password_auto("Please enter security token PIN:", "drive-harddisk", NULL, "fido2-pin", "cryptsetup.fido2-pin", until, flags, &pins);
if (r < 0)
return log_error_errno(r, "Failed to ask for user password: %m");
flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
}
}
int find_fido2_auto_data(
struct crypt_device *cd,
char **ret_rp_id,
void **ret_salt,
size_t *ret_salt_size,
void **ret_cid,
size_t *ret_cid_size,
int *ret_keyslot) {
_cleanup_free_ void *cid = NULL, *salt = NULL;
size_t cid_size = 0, salt_size = 0;
_cleanup_free_ char *rp = NULL;
int r, keyslot = -1;
assert(cd);
assert(ret_salt);
assert(ret_salt_size);
assert(ret_cid);
assert(ret_cid_size);
assert(ret_keyslot);
/* Loads FIDO2 metadata from LUKS2 JSON token headers. */
for (int token = 0; token < sym_crypt_token_max(CRYPT_LUKS2); token ++) {
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
JsonVariant *w;
r = cryptsetup_get_token_as_json(cd, token, "systemd-fido2", &v);
if (IN_SET(r, -ENOENT, -EINVAL, -EMEDIUMTYPE))
continue;
if (r < 0)
return log_error_errno(r, "Failed to read JSON token data off disk: %m");
if (cid)
return log_error_errno(SYNTHETIC_ERRNO(ENOTUNIQ),
"Multiple FIDO2 tokens enrolled, cannot automatically determine token.");
w = json_variant_by_key(v, "fido2-credential");
if (!w || !json_variant_is_string(w))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"FIDO2 token data lacks 'fido2-credential' field.");
r = unbase64mem(json_variant_string(w), SIZE_MAX, &cid, &cid_size);
if (r < 0)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Invalid base64 data in 'fido2-credential' field.");
w = json_variant_by_key(v, "fido2-salt");
if (!w || !json_variant_is_string(w))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"FIDO2 token data lacks 'fido2-salt' field.");
assert(!salt);
assert(salt_size == 0);
r = unbase64mem(json_variant_string(w), SIZE_MAX, &salt, &salt_size);
if (r < 0)
return log_error_errno(r, "Failed to decode base64 encoded salt.");
assert(keyslot < 0);
keyslot = cryptsetup_get_keyslot_from_token(v);
if (keyslot < 0)
return log_error_errno(keyslot, "Failed to extract keyslot index from FIDO2 JSON data: %m");
w = json_variant_by_key(v, "fido2-rp");
if (w) {
/* The "rp" field is optional. */
if (!json_variant_is_string(w))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"FIDO2 token data's 'fido2-rp' field is not a string.");
assert(!rp);
rp = strdup(json_variant_string(w));
if (!rp)
return log_oom();
}
}
if (!cid)
return log_error_errno(SYNTHETIC_ERRNO(ENXIO),
"No valid FIDO2 token data found.");
log_info("Automatically discovered security FIDO2 token unlocks volume.");
*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_keyslot = keyslot;
return 0;
}
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