| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include "ask-password-api.h" |
| #include "cryptsetup-fido2.h" |
| #include "env-util.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, |
| Fido2EnrollFlags required, |
| void **ret_decrypted_key, |
| size_t *ret_decrypted_key_size, |
| AskPasswordFlags ask_password_flags) { |
| |
| _cleanup_(erase_and_freep) char *envpw = NULL; |
| _cleanup_strv_free_erase_ char **pins = NULL; |
| _cleanup_free_ void *loaded_salt = NULL; |
| bool device_exists = false; |
| const char *salt; |
| size_t salt_size; |
| int r; |
| |
| if ((required & (FIDO2ENROLL_PIN | FIDO2ENROLL_UP | FIDO2ENROLL_UV)) && headless) |
| return log_error_errno(SYNTHETIC_ERRNO(ENOPKG), |
| "Local verification is required to unlock this volume, but the 'headless' parameter was set."); |
| |
| ask_password_flags |= ASK_PASSWORD_PUSH_CACHE | ASK_PASSWORD_ACCEPT_CACHED; |
| |
| 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; |
| } |
| |
| r = getenv_steal_erase("PIN", &envpw); |
| if (r < 0) |
| return log_error_errno(r, "Failed to acquire password from environment: %m"); |
| if (r > 0) { |
| pins = strv_new(envpw); |
| if (!pins) |
| return log_oom(); |
| } |
| |
| for (;;) { |
| if (!device_exists) { |
| /* Before we inquire for the PIN we'll need, if we never talked to the device, check |
| * if the device actually is plugged in. Otherwise we'll ask for the PIN already when |
| * the device is not plugged in, which is confusing. */ |
| |
| r = fido2_have_device(device); |
| if (r < 0) |
| return r; |
| if (r == 0) /* no device found, return EAGAIN so that caller will wait/watch udev */ |
| return -EAGAIN; |
| |
| device_exists = true; /* now we know for sure, a device exists, no need to ask again */ |
| } |
| |
| /* Always make an attempt before asking for PIN. |
| * fido2_use_hmac_hash() will perform a pre-flight check for whether the credential for |
| * can be found on one of the connected devices. This way, we can avoid prompting the user |
| * for a PIN when we are sure that no device can be used. */ |
| r = fido2_use_hmac_hash( |
| device, |
| rp_id ?: "io.systemd.cryptsetup", |
| salt, salt_size, |
| cid, cid_size, |
| pins, |
| required, |
| ret_decrypted_key, |
| ret_decrypted_key_size); |
| if (!IN_SET(r, |
| -ENOANO, /* needs pin */ |
| -ENOLCK)) /* pin incorrect */ |
| return r; |
| |
| device_exists = true; /* that a PIN is needed/wasn't correct means that we managed to |
| * talk to a device */ |
| |
| if (headless) |
| return log_error_errno(SYNTHETIC_ERRNO(ENOPKG), "PIN querying disabled via 'headless' option. Use the '$PIN' environment variable."); |
| |
| pins = strv_free_erase(pins); |
| r = ask_password_auto("Please enter security token PIN:", "drive-harddisk", NULL, "fido2-pin", "cryptsetup.fido2-pin", until, ask_password_flags, &pins); |
| if (r < 0) |
| return log_error_errno(r, "Failed to ask for user password: %m"); |
| |
| ask_password_flags &= ~ASK_PASSWORD_ACCEPT_CACHED; |
| } |
| } |
| |
| int acquire_fido2_key_auto( |
| struct crypt_device *cd, |
| const char *name, |
| const char *friendly_name, |
| const char *fido2_device, |
| usec_t until, |
| bool headless, |
| void **ret_decrypted_key, |
| size_t *ret_decrypted_key_size, |
| AskPasswordFlags ask_password_flags) { |
| |
| _cleanup_free_ void *cid = NULL; |
| size_t cid_size = 0; |
| int r, ret = -ENOENT; |
| Fido2EnrollFlags required = 0; |
| |
| assert(cd); |
| assert(name); |
| assert(ret_decrypted_key); |
| assert(ret_decrypted_key_size); |
| |
| /* 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; |
| _cleanup_free_ void *salt = NULL; |
| _cleanup_free_ char *rp = NULL; |
| size_t salt_size = 0; |
| int ks; |
| |
| 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"); |
| |
| ks = cryptsetup_get_keyslot_from_token(v); |
| if (ks < 0) { |
| /* Handle parsing errors of the keyslots field gracefully, since it's not 'owned' by |
| * us, but by the LUKS2 spec */ |
| log_warning_errno(ks, "Failed to extract keyslot index from FIDO2 JSON data token %i, skipping: %m", token); |
| continue; |
| } |
| |
| 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."); |
| |
| 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(); |
| } |
| |
| w = json_variant_by_key(v, "fido2-clientPin-required"); |
| if (w) { |
| /* The "fido2-clientPin-required" field is optional. */ |
| |
| if (!json_variant_is_boolean(w)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "FIDO2 token data's 'fido2-clientPin-required' field is not a boolean."); |
| |
| 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. */ |
| |
| if (!json_variant_is_boolean(w)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "FIDO2 token data's 'fido2-up-required' field is not a boolean."); |
| |
| 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. */ |
| |
| if (!json_variant_is_boolean(w)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "FIDO2 token data's 'fido2-uv-required' field is not a boolean."); |
| |
| SET_FLAG(required, FIDO2ENROLL_UV, json_variant_boolean(w)); |
| } else |
| required |= FIDO2ENROLL_UV_OMIT; /* compat with 248 */ |
| |
| ret = acquire_fido2_key( |
| name, |
| friendly_name, |
| fido2_device, |
| rp, |
| cid, cid_size, |
| /* key_file= */ NULL, /* salt is read from LUKS header instead of key_file */ |
| /* key_file_size= */ 0, |
| /* key_file_offset= */ 0, |
| salt, salt_size, |
| until, |
| headless, |
| required, |
| ret_decrypted_key, ret_decrypted_key_size, |
| ask_password_flags); |
| if (ret == 0) |
| break; |
| } |
| |
| if (!cid) |
| return log_error_errno(SYNTHETIC_ERRNO(ENXIO), |
| "No valid FIDO2 token data found."); |
| |
| if (ret == -EAGAIN) /* fido2 device does not exist, or UV is blocked; caller will prompt for retry */ |
| return log_debug_errno(ret, "FIDO2 token does not exist, or UV is blocked."); |
| if (ret < 0) |
| return log_error_errno(ret, "Failed to unlock LUKS volume with FIDO2 token: %m"); |
| |
| log_info("Unlocked volume via automatically discovered security FIDO2 token."); |
| return ret; |
| } |
