| /* 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 "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 pcr_mask, |
| uint16_t pcr_bank, |
| 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, |
| TPM2Flags flags, |
| usec_t until, |
| bool headless, |
| AskPasswordFlags ask_password_flags, |
| void **ret_decrypted_key, |
| size_t *ret_decrypted_key_size) { |
| |
| _cleanup_free_ void *loaded_blob = NULL; |
| _cleanup_free_ char *auto_device = NULL; |
| size_t blob_size; |
| const void *blob; |
| int r; |
| |
| 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 (!(flags & TPM2_FLAGS_USE_PIN)) |
| return tpm2_unseal( |
| device, |
| pcr_mask, |
| pcr_bank, |
| primary_alg, |
| blob, |
| blob_size, |
| policy_hash, |
| policy_hash_size, |
| NULL, |
| ret_decrypted_key, |
| ret_decrypted_key_size); |
| |
| for (int i = 5;; i--) { |
| _cleanup_(erase_and_freep) char *pin_str = NULL; |
| |
| if (i <= 0) |
| return -EACCES; |
| |
| r = get_pin(until, ask_password_flags, headless, &pin_str); |
| if (r < 0) |
| return r; |
| |
| r = tpm2_unseal( |
| device, |
| pcr_mask, |
| pcr_bank, |
| primary_alg, |
| blob, |
| blob_size, |
| policy_hash, |
| policy_hash_size, |
| pin_str, |
| 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_pcr_mask, |
| uint16_t *ret_pcr_bank, |
| uint16_t *ret_primary_alg, |
| void **ret_blob, |
| size_t *ret_blob_size, |
| void **ret_policy_hash, |
| size_t *ret_policy_hash_size, |
| int *ret_keyslot, |
| int *ret_token, |
| TPM2Flags *ret_flags) { |
| |
| _cleanup_free_ void *blob = NULL, *policy_hash = NULL; |
| size_t blob_size = 0, policy_hash_size = 0; |
| int r, keyslot = -1, token = -1; |
| TPM2Flags flags = 0; |
| uint32_t pcr_mask = 0; |
| uint16_t pcr_bank = UINT16_MAX; /* default: pick automatically */ |
| uint16_t primary_alg = TPM2_ALG_ECC; /* ECC was the only supported algorithm in systemd < 250, use that as implied default, for compatibility */ |
| |
| assert(cd); |
| |
| for (token = start_token; token < sym_crypt_token_max(CRYPT_LUKS2); token++) { |
| _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; |
| JsonVariant *w, *e; |
| int ks; |
| |
| 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"); |
| |
| 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 TPM2 JSON data token %i, skipping: %m", token); |
| continue; |
| } |
| |
| w = json_variant_by_key(v, "tpm2-pcrs"); |
| if (!w || !json_variant_is_array(w)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 token data lacks 'tpm2-pcrs' field."); |
| |
| assert(pcr_mask == 0); |
| JSON_VARIANT_ARRAY_FOREACH(e, w) { |
| uint64_t u; |
| |
| if (!json_variant_is_number(e)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 PCR is not a number."); |
| |
| u = json_variant_unsigned(e); |
| if (u >= TPM2_PCRS_MAX) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 PCR number out of range."); |
| |
| pcr_mask |= UINT32_C(1) << u; |
| } |
| |
| if (search_pcr_mask != UINT32_MAX && |
| search_pcr_mask != pcr_mask) /* PCR mask doesn't match what is configured, ignore this entry */ |
| continue; |
| |
| assert(keyslot < 0); |
| keyslot = ks; |
| |
| assert(pcr_bank == UINT16_MAX); |
| assert(primary_alg == TPM2_ALG_ECC); |
| |
| /* 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)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 PCR bank is not a string."); |
| |
| r = tpm2_pcr_bank_from_string(json_variant_string(w)); |
| if (r < 0) |
| return log_error_errno(r, "TPM2 PCR bank invalid or not supported: %s", json_variant_string(w)); |
| |
| pcr_bank = r; |
| } |
| |
| /* 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)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 primary key algorithm is not a string."); |
| |
| r = tpm2_primary_alg_from_string(json_variant_string(w)); |
| if (r < 0) |
| return log_error_errno(r, "TPM2 primary key algorithm invalid or not supported: %s", json_variant_string(w)); |
| |
| primary_alg = r; |
| } |
| |
| assert(!blob); |
| w = json_variant_by_key(v, "tpm2-blob"); |
| if (!w || !json_variant_is_string(w)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 token data lacks 'tpm2-blob' field."); |
| |
| r = unbase64mem(json_variant_string(w), SIZE_MAX, &blob, &blob_size); |
| if (r < 0) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "Invalid base64 data in 'tpm2-blob' field."); |
| |
| assert(!policy_hash); |
| w = json_variant_by_key(v, "tpm2-policy-hash"); |
| if (!w || !json_variant_is_string(w)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 token data lacks 'tpm2-policy-hash' field."); |
| |
| r = unhexmem(json_variant_string(w), SIZE_MAX, &policy_hash, &policy_hash_size); |
| if (r < 0) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "Invalid base64 data in 'tpm2-policy-hash' field."); |
| |
| w = json_variant_by_key(v, "tpm2-pin"); |
| if (w) { |
| if (!json_variant_is_boolean(w)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "TPM2 PIN policy is not a boolean."); |
| |
| if (json_variant_boolean(w)) |
| flags |= TPM2_FLAGS_USE_PIN; |
| } |
| |
| break; |
| } |
| |
| if (!blob) |
| return log_error_errno(SYNTHETIC_ERRNO(ENXIO), |
| "No valid TPM2 token data found."); |
| |
| if (start_token <= 0) |
| log_info("Automatically discovered security TPM2 token unlocks volume."); |
| |
| *ret_pcr_mask = pcr_mask; |
| *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_keyslot = keyslot; |
| *ret_token = token; |
| *ret_pcr_bank = pcr_bank; |
| *ret_primary_alg = primary_alg; |
| *ret_flags = flags; |
| |
| return 0; |
| } |