| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include "alloc-util.h" |
| #include "ask-password-api.h" |
| #include "cryptsetup-tpm2.h" |
| #include "env-util.h" |
| #include "fileio.h" |
| #include "hexdecoct.h" |
| #include "json.h" |
| #include "parse-util.h" |
| #include "random-util.h" |
| #include "sha256.h" |
| #include "tpm2-util.h" |
| |
| static int get_pin(usec_t until, AskPasswordFlags ask_password_flags, bool headless, char **ret_pin_str) { |
| _cleanup_free_ char *pin_str = NULL; |
| _cleanup_strv_free_erase_ char **pin = NULL; |
| int r; |
| |
| assert(ret_pin_str); |
| |
| r = getenv_steal_erase("PIN", &pin_str); |
| if (r < 0) |
| return log_error_errno(r, "Failed to acquire PIN from environment: %m"); |
| if (!r) { |
| if (headless) |
| return log_error_errno( |
| SYNTHETIC_ERRNO(ENOPKG), |
| "PIN querying disabled via 'headless' option. " |
| "Use the '$PIN' environment variable."); |
| |
| pin = strv_free_erase(pin); |
| r = ask_password_auto( |
| "Please enter TPM2 PIN:", |
| "drive-harddisk", |
| NULL, |
| "tpm2-pin", |
| "cryptsetup.tpm2-pin", |
| until, |
| ask_password_flags, |
| &pin); |
| if (r < 0) |
| return log_error_errno(r, "Failed to ask for user pin: %m"); |
| assert(strv_length(pin) == 1); |
| |
| pin_str = strdup(pin[0]); |
| if (!pin_str) |
| return log_oom(); |
| } |
| |
| *ret_pin_str = TAKE_PTR(pin_str); |
| |
| return r; |
| } |
| |
| int acquire_tpm2_key( |
| const char *volume_name, |
| const char *device, |
| uint32_t hash_pcr_mask, |
| uint16_t pcr_bank, |
| const void *pubkey, |
| size_t pubkey_size, |
| uint32_t pubkey_pcr_mask, |
| const char *signature_path, |
| uint16_t primary_alg, |
| const char *key_file, |
| size_t key_file_size, |
| uint64_t key_file_offset, |
| const void *key_data, |
| size_t key_data_size, |
| const void *policy_hash, |
| size_t policy_hash_size, |
| const void *salt, |
| size_t salt_size, |
| TPM2Flags flags, |
| usec_t until, |
| bool headless, |
| AskPasswordFlags ask_password_flags, |
| void **ret_decrypted_key, |
| size_t *ret_decrypted_key_size) { |
| |
| _cleanup_(json_variant_unrefp) JsonVariant *signature_json = NULL; |
| _cleanup_free_ void *loaded_blob = NULL; |
| _cleanup_free_ char *auto_device = NULL; |
| size_t blob_size; |
| const void *blob; |
| int r; |
| |
| assert(salt || salt_size == 0); |
| |
| if (!device) { |
| r = tpm2_find_device_auto(LOG_DEBUG, &auto_device); |
| if (r == -ENODEV) |
| return -EAGAIN; /* Tell the caller to wait for a TPM2 device to show up */ |
| if (r < 0) |
| return r; |
| |
| device = auto_device; |
| } |
| |
| if (key_data) { |
| blob = key_data; |
| blob_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-tpm2/%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_blob, &blob_size); |
| if (r < 0) |
| return r; |
| |
| blob = loaded_blob; |
| } |
| |
| if (pubkey_pcr_mask != 0) { |
| r = tpm2_load_pcr_signature(signature_path, &signature_json); |
| if (r < 0) |
| return r; |
| } |
| |
| if (!(flags & TPM2_FLAGS_USE_PIN)) |
| return tpm2_unseal( |
| device, |
| hash_pcr_mask, |
| pcr_bank, |
| pubkey, pubkey_size, |
| pubkey_pcr_mask, |
| signature_json, |
| /* pin= */ NULL, |
| primary_alg, |
| blob, |
| blob_size, |
| policy_hash, |
| policy_hash_size, |
| ret_decrypted_key, |
| ret_decrypted_key_size); |
| |
| for (int i = 5;; i--) { |
| _cleanup_(erase_and_freep) char *pin_str = NULL, *b64_salted_pin = NULL; |
| |
| if (i <= 0) |
| return -EACCES; |
| |
| r = get_pin(until, ask_password_flags, headless, &pin_str); |
| if (r < 0) |
| return r; |
| |
| if (salt_size > 0) { |
| uint8_t salted_pin[SHA256_DIGEST_SIZE] = {}; |
| CLEANUP_ERASE(salted_pin); |
| |
| r = tpm2_util_pbkdf2_hmac_sha256(pin_str, strlen(pin_str), salt, salt_size, salted_pin); |
| if (r < 0) |
| return log_error_errno(r, "Failed to perform PBKDF2: %m"); |
| |
| r = base64mem(salted_pin, sizeof(salted_pin), &b64_salted_pin); |
| if (r < 0) |
| return log_error_errno(r, "Failed to base64 encode salted pin: %m"); |
| } else |
| /* no salting needed, backwards compat with non-salted pins */ |
| b64_salted_pin = TAKE_PTR(pin_str); |
| |
| r = tpm2_unseal(device, |
| hash_pcr_mask, |
| pcr_bank, |
| pubkey, pubkey_size, |
| pubkey_pcr_mask, |
| signature_json, |
| b64_salted_pin, |
| primary_alg, |
| blob, |
| blob_size, |
| policy_hash, |
| policy_hash_size, |
| ret_decrypted_key, |
| ret_decrypted_key_size); |
| /* We get this error in case there is an authentication policy mismatch. This should |
| * not happen, but this avoids confusing behavior, just in case. */ |
| if (IN_SET(r, -EPERM, -ENOLCK)) |
| return r; |
| if (r < 0) |
| continue; |
| |
| return r; |
| } |
| } |
| |
| int find_tpm2_auto_data( |
| struct crypt_device *cd, |
| uint32_t search_pcr_mask, |
| int start_token, |
| uint32_t *ret_hash_pcr_mask, |
| uint16_t *ret_pcr_bank, |
| void **ret_pubkey, |
| size_t *ret_pubkey_size, |
| uint32_t *ret_pubkey_pcr_mask, |
| uint16_t *ret_primary_alg, |
| void **ret_blob, |
| size_t *ret_blob_size, |
| void **ret_policy_hash, |
| size_t *ret_policy_hash_size, |
| void **ret_salt, |
| size_t *ret_salt_size, |
| TPM2Flags *ret_flags, |
| int *ret_keyslot, |
| int *ret_token) { |
| |
| int r, token; |
| |
| assert(cd); |
| |
| for (token = start_token; token < sym_crypt_token_max(CRYPT_LUKS2); token++) { |
| _cleanup_free_ void *blob = NULL, *policy_hash = NULL, *pubkey = NULL, *salt = NULL; |
| _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; |
| size_t blob_size, policy_hash_size, pubkey_size, salt_size = 0; |
| uint32_t hash_pcr_mask, pubkey_pcr_mask; |
| uint16_t pcr_bank, primary_alg; |
| TPM2Flags flags; |
| int keyslot; |
| |
| r = cryptsetup_get_token_as_json(cd, token, "systemd-tpm2", &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"); |
| |
| r = tpm2_parse_luks2_json( |
| v, |
| &keyslot, |
| &hash_pcr_mask, |
| &pcr_bank, |
| &pubkey, &pubkey_size, |
| &pubkey_pcr_mask, |
| &primary_alg, |
| &blob, &blob_size, |
| &policy_hash, &policy_hash_size, |
| &salt, &salt_size, |
| &flags); |
| if (r == -EUCLEAN) /* Gracefully handle issues in JSON fields not owned by us */ |
| continue; |
| if (r < 0) |
| return log_error_errno(r, "Failed to parse TPM2 JSON data: %m"); |
| |
| if (search_pcr_mask == UINT32_MAX || |
| search_pcr_mask == hash_pcr_mask) { |
| |
| if (start_token <= 0) |
| log_info("Automatically discovered security TPM2 token unlocks volume."); |
| |
| *ret_hash_pcr_mask = hash_pcr_mask; |
| *ret_pcr_bank = pcr_bank; |
| *ret_pubkey = TAKE_PTR(pubkey); |
| *ret_pubkey_size = pubkey_size; |
| *ret_pubkey_pcr_mask = pubkey_pcr_mask; |
| *ret_primary_alg = primary_alg; |
| *ret_blob = TAKE_PTR(blob); |
| *ret_blob_size = blob_size; |
| *ret_policy_hash = TAKE_PTR(policy_hash); |
| *ret_policy_hash_size = policy_hash_size; |
| *ret_salt = TAKE_PTR(salt); |
| *ret_salt_size = salt_size; |
| *ret_keyslot = keyslot; |
| *ret_token = token; |
| *ret_flags = flags; |
| return 0; |
| } |
| |
| /* PCR mask doesn't match what is configured, ignore this entry, let's see next */ |
| } |
| |
| return log_error_errno(SYNTHETIC_ERRNO(ENXIO), "No valid TPM2 token data found."); |
| } |
