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/* 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 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,
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;
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;
if (i <= 0)
return -EACCES;
r = get_pin(until, ask_password_flags, headless, &pin_str);
if (r < 0)
return r;
r = tpm2_unseal(device,
hash_pcr_mask,
pcr_bank,
pubkey, pubkey_size,
pubkey_pcr_mask,
signature_json,
pin_str,
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,
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;
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
size_t blob_size, policy_hash_size, pubkey_size;
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,
&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_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.");
}
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