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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <libcryptsetup.h>
#include <string.h>
#include "cryptsetup-token.h"
#include "cryptsetup-token-util.h"
#include "hexdecoct.h"
#include "json.h"
#include "luks2-fido2.h"
#include "memory-util.h"
#include "version.h"
#define TOKEN_NAME "systemd-fido2"
#define TOKEN_VERSION_MAJOR "1"
#define TOKEN_VERSION_MINOR "0"
/* for libcryptsetup debug purpose */
_public_ const char *cryptsetup_token_version(void) {
return TOKEN_VERSION_MAJOR "." TOKEN_VERSION_MINOR " systemd-v" PROJECT_VERSION_FULL " (" GIT_VERSION ")";
}
_public_ int cryptsetup_token_open_pin(
struct crypt_device *cd, /* is always LUKS2 context */
int token /* is always >= 0 */,
const char *pin,
size_t pin_size,
char **password, /* freed by cryptsetup_token_buffer_free */
size_t *password_len,
void *usrptr /* plugin defined parameter passed to crypt_activate_by_token*() API */) {
int r;
const char *json;
_cleanup_(erase_and_freep) char *pin_string = NULL;
assert(pin || pin_size == 0);
assert(token >= 0);
/* This must not fail at this moment (internal error) */
r = crypt_token_json_get(cd, token, &json);
/* Use assert_se() here to avoid emitting warning with -DNDEBUG */
assert_se(token == r);
assert(json);
r = crypt_normalize_pin(pin, pin_size, &pin_string);
if (r < 0)
return crypt_log_debug_errno(cd, r, "Cannot normalize PIN: %m");
return acquire_luks2_key(cd, json, (const char *)usrptr, pin_string, password, password_len);
}
/*
* This function is called from within following libcryptsetup calls
* provided conditions further below are met:
*
* crypt_activate_by_token(), crypt_activate_by_token_type(type == 'systemd-fido2'):
*
* - token is assigned to at least one luks2 keyslot eligible to activate LUKS2 device
* (alternatively: name is set to null, flags contains CRYPT_ACTIVATE_ALLOW_UNBOUND_KEY
* and token is assigned to at least single keyslot).
*
* - if plugin defines validate function (see cryptsetup_token_validate below) it must have
* passed the check (aka return 0)
*/
_public_ int cryptsetup_token_open(
struct crypt_device *cd, /* is always LUKS2 context */
int token /* is always >= 0 */,
char **password, /* freed by cryptsetup_token_buffer_free */
size_t *password_len,
void *usrptr /* plugin defined parameter passed to crypt_activate_by_token*() API */) {
return cryptsetup_token_open_pin(cd, token, NULL, 0, password, password_len, usrptr);
}
/*
* libcryptsetup callback for memory deallocation of 'password' parameter passed in
* any crypt_token_open_* plugin function
*/
_public_ void cryptsetup_token_buffer_free(void *buffer, size_t buffer_len) {
erase_and_free(buffer);
}
/*
* prints systemd-fido2 token content in crypt_dump().
* 'type' and 'keyslots' fields are printed by libcryptsetup
*/
_public_ void cryptsetup_token_dump(
struct crypt_device *cd /* is always LUKS2 context */,
const char *json /* validated 'systemd-fido2' token if cryptsetup_token_validate is defined */) {
int r;
Fido2EnrollFlags required;
size_t cid_size, salt_size;
const char *client_pin_req_str, *up_req_str, *uv_req_str;
_cleanup_free_ void *cid = NULL, *salt = NULL;
_cleanup_free_ char *rp_id = NULL, *cid_str = NULL, *salt_str = NULL;
assert(json);
r = parse_luks2_fido2_data(cd, json, &rp_id, &salt, &salt_size, &cid, &cid_size, &required);
if (r < 0)
return (void) crypt_log_debug_errno(cd, r, "Failed to parse " TOKEN_NAME " metadata: %m.");
r = crypt_dump_buffer_to_hex_string(cid, cid_size, &cid_str);
if (r < 0)
return (void) crypt_log_debug_errno(cd, r, "Cannot dump " TOKEN_NAME " content: %m");
r = crypt_dump_buffer_to_hex_string(salt, salt_size, &salt_str);
if (r < 0)
return (void) crypt_log_debug_errno(cd, r, "Cannot dump " TOKEN_NAME " content: %m");
if (required & FIDO2ENROLL_PIN)
client_pin_req_str = "true";
else if (required & FIDO2ENROLL_PIN_IF_NEEDED)
client_pin_req_str = NULL;
else
client_pin_req_str = "false";
if (required & FIDO2ENROLL_UP)
up_req_str = "true";
else if (required & FIDO2ENROLL_UP_IF_NEEDED)
up_req_str = NULL;
else
up_req_str = "false";
if (required & FIDO2ENROLL_UV)
uv_req_str = "true";
else if (required & FIDO2ENROLL_UV_OMIT)
uv_req_str = NULL;
else
uv_req_str = "false";
crypt_log(cd, "\tfido2-credential:" CRYPT_DUMP_LINE_SEP "%s\n", cid_str);
crypt_log(cd, "\tfido2-salt: %s\n", salt_str);
/* optional fields */
if (rp_id)
crypt_log(cd, "\tfido2-rp: %s\n", rp_id);
if (client_pin_req_str)
crypt_log(cd, "\tfido2-clientPin-required:" CRYPT_DUMP_LINE_SEP "%s\n",
client_pin_req_str);
if (up_req_str)
crypt_log(cd, "\tfido2-up-required:" CRYPT_DUMP_LINE_SEP "%s\n", up_req_str);
if (uv_req_str)
crypt_log(cd, "\tfido2-uv-required:" CRYPT_DUMP_LINE_SEP "%s\n", uv_req_str);
}
/*
* Note:
* If plugin is available in library path, it's called in before following libcryptsetup calls:
*
* crypt_token_json_set, crypt_dump, any crypt_activate_by_token_* flavour
*/
_public_ int cryptsetup_token_validate(
struct crypt_device *cd, /* is always LUKS2 context */
const char *json /* contains valid 'type' and 'keyslots' fields. 'type' is 'systemd-fido2' */) {
int r;
JsonVariant *w;
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
assert(json);
r = json_parse(json, 0, &v, NULL, NULL);
if (r < 0)
return crypt_log_debug_errno(cd, r, "Could not parse " TOKEN_NAME " json object: %m.");
w = json_variant_by_key(v, "fido2-credential");
if (!w || !json_variant_is_string(w)) {
crypt_log_debug(cd, "FIDO2 token data lacks 'fido2-credential' field.");
return 1;
}
r = unbase64mem(json_variant_string(w), NULL, NULL);
if (r < 0)
return crypt_log_debug_errno(cd, r, "Invalid base64 data in 'fido2-credential' field: %m");
w = json_variant_by_key(v, "fido2-salt");
if (!w || !json_variant_is_string(w)) {
crypt_log_debug(cd, "FIDO2 token data lacks 'fido2-salt' field.");
return 1;
}
r = unbase64mem(json_variant_string(w), NULL, NULL);
if (r < 0)
return crypt_log_debug_errno(cd, r, "Failed to decode base64 encoded salt: %m.");
/* The "rp" field is optional. */
w = json_variant_by_key(v, "fido2-rp");
if (w && !json_variant_is_string(w)) {
crypt_log_debug(cd, "FIDO2 token data's 'fido2-rp' field is not a string.");
return 1;
}
/* The "fido2-clientPin-required" field is optional. */
w = json_variant_by_key(v, "fido2-clientPin-required");
if (w && !json_variant_is_boolean(w)) {
crypt_log_debug(cd, "FIDO2 token data's 'fido2-clientPin-required' field is not a boolean.");
return 1;
}
/* The "fido2-up-required" field is optional. */
w = json_variant_by_key(v, "fido2-up-required");
if (w && !json_variant_is_boolean(w)) {
crypt_log_debug(cd, "FIDO2 token data's 'fido2-up-required' field is not a boolean.");
return 1;
}
/* The "fido2-uv-required" field is optional. */
w = json_variant_by_key(v, "fido2-uv-required");
if (w && !json_variant_is_boolean(w)) {
crypt_log_debug(cd, "FIDO2 token data's 'fido2-uv-required' field is not a boolean.");
return 1;
}
return 0;
}
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