/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include "cryptsetup-token.h" #include "cryptsetup-token-util.h" #include "hexdecoct.h" #include "json.h" #include "luks2-tpm2.h" #include "memory-util.h" #include "strv.h" #include "tpm2-util.h" #include "version.h" #define TOKEN_NAME "systemd-tpm2" #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 ")"; } static int log_debug_open_error(struct crypt_device *cd, int r) { if (r == -EAGAIN) return crypt_log_debug_errno(cd, r, "TPM2 device not found."); if (r == -ENXIO) return crypt_log_debug_errno(cd, r, "No matching TPM2 token data found."); return crypt_log_debug_errno(cd, r, TOKEN_NAME " open failed: %m."); } _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 **ret_password, /* freed by cryptsetup_token_buffer_free */ size_t *ret_password_len, void *usrptr /* plugin defined parameter passed to crypt_activate_by_token*() API */) { _cleanup_(erase_and_freep) char *base64_encoded = NULL, *pin_string = NULL; _cleanup_free_ void *blob = NULL, *pubkey = NULL, *policy_hash = NULL, *salt = NULL, *srk_buf = NULL; size_t blob_size, policy_hash_size, decrypted_key_size, pubkey_size, salt_size = 0, srk_buf_size = 0; _cleanup_(erase_and_freep) void *decrypted_key = NULL; _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; uint32_t hash_pcr_mask, pubkey_pcr_mask; systemd_tpm2_plugin_params params = { .search_pcr_mask = UINT32_MAX }; uint16_t pcr_bank, primary_alg; ssize_t base64_encoded_size; TPM2Flags flags = 0; const char *json; int r; assert(token >= 0); assert(!pin || pin_size > 0); assert(ret_password); assert(ret_password_len); /* This must not fail at this moment (internal error) */ r = crypt_token_json_get(cd, token, &json); assert(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"); if (usrptr) params = *(systemd_tpm2_plugin_params *)usrptr; r = json_parse(json, 0, &v, NULL, NULL); if (r < 0) return crypt_log_debug_errno(cd, r, "Failed to parse token JSON data: %m"); r = tpm2_parse_luks2_json( v, NULL, &hash_pcr_mask, &pcr_bank, &pubkey, &pubkey_size, &pubkey_pcr_mask, &primary_alg, &blob, &blob_size, &policy_hash, &policy_hash_size, &salt, &salt_size, &srk_buf, &srk_buf_size, &flags); if (r < 0) return log_debug_open_error(cd, r); if (params.search_pcr_mask != UINT32_MAX && hash_pcr_mask != params.search_pcr_mask) return crypt_log_debug_errno(cd, ENXIO, "PCR mask doesn't match expectation (%" PRIu32 " vs. %" PRIu32 ")", hash_pcr_mask, params.search_pcr_mask); r = acquire_luks2_key( params.device, hash_pcr_mask, pcr_bank, pubkey, pubkey_size, pubkey_pcr_mask, params.signature_path, pin_string, params.pcrlock_path, primary_alg, blob, blob_size, policy_hash, policy_hash_size, salt, salt_size, srk_buf, srk_buf_size, flags, &decrypted_key, &decrypted_key_size); if (r < 0) return log_debug_open_error(cd, 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 log_debug_open_error(cd, base64_encoded_size); /* free'd automatically by libcryptsetup */ *ret_password = TAKE_PTR(base64_encoded); *ret_password_len = base64_encoded_size; return 0; } /* * 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-tpm2'): * * - 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 **ret_password, /* freed by cryptsetup_token_buffer_free */ size_t *ret_password_len, void *usrptr /* plugin defined parameter passed to crypt_activate_by_token*() API */) { return cryptsetup_token_open_pin(cd, token, NULL, 0, ret_password, ret_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-tpm2 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 */) { _cleanup_free_ char *hash_pcrs_str = NULL, *pubkey_pcrs_str = NULL, *blob_str = NULL, *policy_hash_str = NULL, *pubkey_str = NULL; _cleanup_free_ void *blob = NULL, *pubkey = NULL, *policy_hash = NULL, *salt = NULL, *srk_buf = NULL; _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; size_t blob_size, policy_hash_size, pubkey_size, salt_size = 0, srk_buf_size = 0; uint32_t hash_pcr_mask, pubkey_pcr_mask; uint16_t pcr_bank, primary_alg; TPM2Flags flags = 0; int r; assert(json); r = json_parse(json, 0, &v, NULL, NULL); if (r < 0) return (void) crypt_log_debug_errno(cd, r, "Failed to parse " TOKEN_NAME " JSON object: %m"); r = tpm2_parse_luks2_json( v, NULL, &hash_pcr_mask, &pcr_bank, &pubkey, &pubkey_size, &pubkey_pcr_mask, &primary_alg, &blob, &blob_size, &policy_hash, &policy_hash_size, &salt, &salt_size, &srk_buf, &srk_buf_size, &flags); if (r < 0) return (void) crypt_log_debug_errno(cd, r, "Failed to parse " TOKEN_NAME " JSON fields: %m"); hash_pcrs_str = tpm2_pcr_mask_to_string(hash_pcr_mask); if (!hash_pcrs_str) return (void) crypt_log_debug_errno(cd, ENOMEM, "Cannot format PCR hash mask: %m"); pubkey_pcrs_str = tpm2_pcr_mask_to_string(pubkey_pcr_mask); if (!pubkey_pcrs_str) return (void) crypt_log_debug_errno(cd, ENOMEM, "Cannot format PCR hash mask: %m"); r = crypt_dump_buffer_to_hex_string(blob, blob_size, &blob_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(pubkey, pubkey_size, &pubkey_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(policy_hash, policy_hash_size, &policy_hash_str); if (r < 0) return (void) crypt_log_debug_errno(cd, r, "Cannot dump " TOKEN_NAME " content: %m"); crypt_log(cd, "\ttpm2-hash-pcrs: %s\n", strna(hash_pcrs_str)); crypt_log(cd, "\ttpm2-pcr-bank: %s\n", strna(tpm2_hash_alg_to_string(pcr_bank))); crypt_log(cd, "\ttpm2-pubkey:" CRYPT_DUMP_LINE_SEP "%s\n", pubkey_str); crypt_log(cd, "\ttpm2-pubkey-pcrs: %s\n", strna(pubkey_pcrs_str)); crypt_log(cd, "\ttpm2-primary-alg: %s\n", strna(tpm2_asym_alg_to_string(primary_alg))); crypt_log(cd, "\ttpm2-blob: %s\n", blob_str); crypt_log(cd, "\ttpm2-policy-hash:" CRYPT_DUMP_LINE_SEP "%s\n", policy_hash_str); crypt_log(cd, "\ttpm2-pin: %s\n", true_false(flags & TPM2_FLAGS_USE_PIN)); crypt_log(cd, "\ttpm2-pcrlock: %s\n", true_false(flags & TPM2_FLAGS_USE_PCRLOCK)); crypt_log(cd, "\ttpm2-salt: %s\n", true_false(salt)); crypt_log(cd, "\ttpm2-srk: %s\n", true_false(srk_buf)); } /* * 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, *e; _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, "tpm2-pcrs"); if (!w || !json_variant_is_array(w)) { crypt_log_debug(cd, "TPM2 token data lacks 'tpm2-pcrs' field."); return 1; } JSON_VARIANT_ARRAY_FOREACH(e, w) { uint64_t u; if (!json_variant_is_number(e)) { crypt_log_debug(cd, "TPM2 PCR is not a number."); return 1; } u = json_variant_unsigned(e); if (!TPM2_PCR_INDEX_VALID(u)) { crypt_log_debug(cd, "TPM2 PCR number out of range."); return 1; } } /* The bank field is optional, since it was added in systemd 250 only. Before the bank was hardcoded * to SHA256. */ w = json_variant_by_key(v, "tpm2-pcr-bank"); if (w) { /* The PCR bank field is optional */ if (!json_variant_is_string(w)) { crypt_log_debug(cd, "TPM2 PCR bank is not a string."); return 1; } if (tpm2_hash_alg_from_string(json_variant_string(w)) < 0) { crypt_log_debug(cd, "TPM2 PCR bank invalid or not supported: %s.", json_variant_string(w)); return 1; } } /* The primary key algorithm field is optional, since it was also added in systemd 250 only. Before * the algorithm was hardcoded to ECC. */ w = json_variant_by_key(v, "tpm2-primary-alg"); if (w) { /* The primary key algorithm is optional */ if (!json_variant_is_string(w)) { crypt_log_debug(cd, "TPM2 primary key algorithm is not a string."); return 1; } if (tpm2_asym_alg_from_string(json_variant_string(w)) < 0) { crypt_log_debug(cd, "TPM2 primary key algorithm invalid or not supported: %s", json_variant_string(w)); return 1; } } w = json_variant_by_key(v, "tpm2-blob"); if (!w || !json_variant_is_string(w)) { crypt_log_debug(cd, "TPM2 token data lacks 'tpm2-blob' 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 'tpm2-blob' field: %m"); w = json_variant_by_key(v, "tpm2-policy-hash"); if (!w || !json_variant_is_string(w)) { crypt_log_debug(cd, "TPM2 token data lacks 'tpm2-policy-hash' field."); return 1; } r = unhexmem(json_variant_string(w), SIZE_MAX, NULL, NULL); if (r < 0) return crypt_log_debug_errno(cd, r, "Invalid base64 data in 'tpm2-policy-hash' field: %m"); w = json_variant_by_key(v, "tpm2-pin"); if (w) { if (!json_variant_is_boolean(w)) { crypt_log_debug(cd, "TPM2 PIN policy is not a boolean."); return 1; } } return 0; }