diff options
Diffstat (limited to 'src/cryptsetup/cryptsetup-tokens/cryptsetup-token-systemd-fido2.c')
| -rw-r--r-- | src/cryptsetup/cryptsetup-tokens/cryptsetup-token-systemd-fido2.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/src/cryptsetup/cryptsetup-tokens/cryptsetup-token-systemd-fido2.c b/src/cryptsetup/cryptsetup-tokens/cryptsetup-token-systemd-fido2.c new file mode 100644 index 0000000..fdb3b17 --- /dev/null +++ b/src/cryptsetup/cryptsetup-tokens/cryptsetup-token-systemd-fido2.c @@ -0,0 +1,218 @@ +/* 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" STRINGIFY(PROJECT_VERSION) " (" 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); + 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-tpm2' 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-tpm2' */) { + + 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), SIZE_MAX, 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), SIZE_MAX, 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; +} |