log_info("Retrieved PIN from TPM2 in %s.", FORMAT_TIMESPAN(usec_sub_unsigned(now(CLOCK_MONOTONIC), pin_start_usec), 1));
}
- TPM2B_NV_PUBLIC nv_public = {};
+ /* Now convert the PIN into an HMAC-SHA256 key that we can use in PolicySigned to protect access to the nvindex with */
+ _cleanup_(tpm2_handle_freep) Tpm2Handle *pin_handle = NULL;
+ r = tpm2_hmac_key_from_pin(tc, encryption_session, &auth, &pin_handle);
+ if (r < 0)
+ return r;
+ TPM2B_NV_PUBLIC nv_public = {};
usec_t nv_index_start_usec = now(CLOCK_MONOTONIC);
if (!iovec_is_set(&nv_blob)) {
+ _cleanup_(Esys_Freep) TPM2B_NAME *pin_name = NULL;
+ r = tpm2_get_name(
+ tc,
+ pin_handle,
+ &pin_name);
+ if (r < 0)
+ return log_error_errno(r, "Failed to get name of PIN from TPM2: %m");
+
TPM2B_DIGEST recovery_policy_digest = TPM2B_DIGEST_MAKE(NULL, TPM2_SHA256_DIGEST_SIZE);
- r = tpm2_calculate_policy_auth_value(&recovery_policy_digest);
+ r = tpm2_calculate_policy_signed(&recovery_policy_digest, pin_name);
if (r < 0)
- return log_error_errno(r, "Failed to calculate authentication value policy: %m");
+ return log_error_errno(r, "Failed to calculate PolicySigned policy: %m");
log_debug("Allocating NV index to write PCR policy to...");
r = tpm2_define_policy_nv_index(
return log_error_errno(r, "Failed to allocate NV index: %m");
}
- r = tpm2_set_auth_binary(tc, nv_handle, &auth);
- if (r < 0)
- return log_error_errno(r, "Failed to set authentication value on NV index: %m");
-
_cleanup_(tpm2_handle_freep) Tpm2Handle *policy_session = NULL;
r = tpm2_make_policy_session(
tc,
if (r < 0)
return log_error_errno(r, "Failed to allocate policy session: %m");
- r = tpm2_policy_auth_value(
+ r = tpm2_policy_signed_hmac_sha256(
tc,
policy_session,
+ pin_handle,
+ &IOVEC_MAKE(auth.buffer, auth.size),
/* ret_policy_digest= */ NULL);
if (r < 0)
return log_error_errno(r, "Failed to submit authentication value policy: %m");
#include "recurse-dir.h"
#include "sha256.h"
#include "sort-util.h"
+#include "sparse-endian.h"
#include "stat-util.h"
#include "string-table.h"
#include "sync-util.h"
return tpm2_get_policy_digest(c, session, ret_policy_digest);
}
+/* Extend 'digest' with the PolicySigned calculated hash. */
+int tpm2_calculate_policy_signed(TPM2B_DIGEST *digest, const TPM2B_NAME *name) {
+ TPM2_CC command = TPM2_CC_PolicySigned;
+ TSS2_RC rc;
+ int r;
+
+ assert(digest);
+ assert(digest->size == SHA256_DIGEST_SIZE);
+ assert(name);
+
+ r = dlopen_tpm2();
+ if (r < 0)
+ return log_debug_errno(r, "TPM2 support not installed: %m");
+
+ uint8_t buf[sizeof(command)];
+ size_t offset = 0;
+
+ rc = sym_Tss2_MU_TPM2_CC_Marshal(command, buf, sizeof(buf), &offset);
+ if (rc != TSS2_RC_SUCCESS)
+ return log_debug_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
+ "Failed to marshal PolicySigned command: %s", sym_Tss2_RC_Decode(rc));
+
+ if (offset != sizeof(command))
+ return log_debug_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
+ "Offset 0x%zx wrong after marshalling PolicySigned command", offset);
+
+ struct iovec data[] = {
+ IOVEC_MAKE(buf, offset),
+ IOVEC_MAKE(name->name, name->size),
+ };
+
+ r = tpm2_digest_many(TPM2_ALG_SHA256, digest, data, ELEMENTSOF(data), /* extend= */ true);
+ if (r < 0)
+ return r;
+
+ const TPM2B_NONCE policyRef = {}; /* For now, we do not make use of the policyRef stuff */
+
+ r = tpm2_digest_buffer(TPM2_ALG_SHA256, digest, policyRef.buffer, policyRef.size, /* extend= */ true);
+ if (r < 0)
+ return r;
+
+ tpm2_log_debug_digest(digest, "PolicySigned calculated digest");
+
+ return 0;
+}
+
+int tpm2_policy_signed_hmac_sha256(
+ Tpm2Context *c,
+ const Tpm2Handle *session,
+ const Tpm2Handle *hmac_key_handle,
+ const struct iovec *hmac_key,
+ TPM2B_DIGEST **ret_policy_digest) {
+
+#if HAVE_OPENSSL
+ TSS2_RC rc;
+ int r;
+
+ assert(c);
+ assert(session);
+ assert(hmac_key_handle);
+ assert(iovec_is_set(hmac_key));
+
+ /* This sends a TPM2_PolicySigned command to the tpm. As signature key we use an HMAC-SHA256 key
+ * specified in the hmac_key parameter. The secret key must be loaded into the TPM already and
+ * referenced in hmac_key_handle. */
+
+ log_debug("Submitting PolicySigned policy for HMAC-SHA256.");
+
+ /* Acquire the nonce from the TPM that we shall sign */
+ _cleanup_(Esys_Freep) TPM2B_NONCE *nonce = NULL;
+ rc = sym_Esys_TRSess_GetNonceTPM(
+ c->esys_context,
+ session->esys_handle,
+ &nonce);
+ if (rc != TSS2_RC_SUCCESS)
+ return log_debug_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
+ "Failed to determine NoneTPM of auth session: %s",
+ sym_Tss2_RC_Decode(rc));
+
+ be32_t expiration = htobe64(0);
+ const TPM2B_DIGEST cpHashA = {}; /* For now, we do not make use of the cpHashA stuff */
+ const TPM2B_NONCE policyRef = {}; /* ditto, we do not bother with policyRef */
+
+ /* Put together the data to sign, as per TPM2 Spec Part 3, 23.3.1 */
+ struct iovec data_to_sign[] = {
+ IOVEC_MAKE(nonce->buffer, nonce->size),
+ IOVEC_MAKE(&expiration, sizeof(expiration)),
+ IOVEC_MAKE(cpHashA.buffer, cpHashA.size),
+ IOVEC_MAKE(policyRef.buffer, policyRef.size),
+ };
+
+ /* Now calculate the digest of the data we put together */
+ TPM2B_DIGEST digest_to_sign;
+ r = tpm2_digest_many(TPM2_ALG_SHA256, &digest_to_sign, data_to_sign, ELEMENTSOF(data_to_sign), /* extend= */ false);
+ if (r < 0)
+ return r;
+
+ unsigned char hmac_signature[SHA256_DIGEST_SIZE];
+ unsigned hmac_signature_size = sizeof(hmac_signature);
+
+ /* And sign this with our key */
+ if (!HMAC(EVP_sha256(),
+ hmac_key->iov_base,
+ hmac_key->iov_len,
+ digest_to_sign.buffer,
+ digest_to_sign.size,
+ hmac_signature,
+ &hmac_signature_size))
+ return -ENOTRECOVERABLE;
+
+ /* Now bring the signature into a format that the TPM understands */
+ TPMT_SIGNATURE sig = {
+ .sigAlg = TPM2_ALG_HMAC,
+ .signature.hmac.hashAlg = TPM2_ALG_SHA256,
+ };
+ assert(hmac_signature_size == sizeof(sig.signature.hmac.digest.sha256));
+ memcpy(sig.signature.hmac.digest.sha256, hmac_signature, hmac_signature_size);
+
+ /* And submit the whole shebang to the TPM */
+ rc = sym_Esys_PolicySigned(
+ c->esys_context,
+ hmac_key_handle->esys_handle,
+ session->esys_handle,
+ /* shandle1= */ ESYS_TR_NONE,
+ /* shandle2= */ ESYS_TR_NONE,
+ /* shandle3= */ ESYS_TR_NONE,
+ nonce,
+ &cpHashA,
+ &policyRef,
+ expiration,
+ &sig,
+ /* timeout= */ NULL,
+ /* policyTicket= */ NULL);
+ if (rc != TSS2_RC_SUCCESS)
+ return log_debug_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
+ "Failed to add PolicySigned policy to TPM: %s",
+ sym_Tss2_RC_Decode(rc));
+
+ return tpm2_get_policy_digest(c, session, ret_policy_digest);
+#else /* HAVE_OPENSSL */
+ return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "OpenSSL support is disabled.");
+#endif
+}
+
int tpm2_calculate_policy_authorize_nv(
const TPM2B_NV_PUBLIC *public_info,
TPM2B_DIGEST *digest) {
*ret = device_key_public;
return 0;
}
+
+int tpm2_hmac_key_from_pin(Tpm2Context *c, const Tpm2Handle *session, const TPM2B_AUTH *pin, Tpm2Handle **ret) {
+ int r;
+
+ assert(c);
+ assert(pin);
+ assert(ret);
+
+ log_debug("Converting PIN into TPM2 HMAC-SHA256 object.");
+
+ /* Load the PIN (which we have stored in the "auth" TPM2B_AUTH) into the TPM as an HMAC key so that
+ * we can use it in a TPM2_PolicySigned() to write to the nvindex. For that we'll prep a pair of
+ * TPM2B_PUBLIC and TPM2B_SENSITIVE that defines an HMAC-SHA256 keyed hash function, and initialize
+ * it based on on the provided PIN data. */
+
+ TPM2B_PUBLIC auth_hmac_public = {
+ .publicArea = {
+ .type = TPM2_ALG_KEYEDHASH,
+ .nameAlg = TPM2_ALG_SHA256,
+ .objectAttributes = TPMA_OBJECT_SIGN_ENCRYPT,
+ .parameters.keyedHashDetail.scheme = {
+ .scheme = TPM2_ALG_HMAC,
+ .details.hmac.hashAlg = TPM2_ALG_SHA256,
+ },
+ .unique.keyedHash.size = SHA256_DIGEST_SIZE,
+ },
+ };
+
+ TPM2B_SENSITIVE auth_hmac_private = {
+ .sensitiveArea = {
+ .sensitiveType = TPM2_ALG_KEYEDHASH,
+ .sensitive.bits.size = pin->size,
+ .seedValue.size = SHA256_DIGEST_SIZE,
+ },
+ };
+
+ /* Copy in the key data */
+ memcpy_safe(auth_hmac_private.sensitiveArea.sensitive.bits.buffer, pin->buffer, pin->size);
+
+ /* NB: We initialize the seed of the TPMT_SENSITIVE structure to all zeroes, since we want a stable
+ * "name" of the PIN object */
+
+ /* Now calculate the "unique" field for the public area, based on the sensitive data, according to
+ * the algorithm in the TPM2 spec, part 1, Section 27.5.3.2 */
+ struct iovec sensitive_data[] = {
+ IOVEC_MAKE(auth_hmac_private.sensitiveArea.seedValue.buffer, auth_hmac_private.sensitiveArea.seedValue.size),
+ IOVEC_MAKE(auth_hmac_private.sensitiveArea.sensitive.bits.buffer, auth_hmac_private.sensitiveArea.sensitive.bits.size),
+ };
+ r = tpm2_digest_many(
+ auth_hmac_public.publicArea.nameAlg,
+ &auth_hmac_public.publicArea.unique.keyedHash,
+ sensitive_data,
+ ELEMENTSOF(sensitive_data),
+ /* extend= */ false);
+ if (r < 0)
+ return r;
+
+ /* And now load the public/private parts into the TPM and get a handle back */
+ r = tpm2_load_external(
+ c,
+ session,
+ &auth_hmac_public,
+ &auth_hmac_private,
+ ret);
+ if (r < 0)
+ return log_error_errno(r, "Failed to load PIN into TPM2: %m");
+
+ return 0;
+}
#endif
char *tpm2_pcr_mask_to_string(uint32_t mask) {
int tpm2_policy_pcr(Tpm2Context *c, const Tpm2Handle *session, const TPML_PCR_SELECTION *pcr_selection, TPM2B_DIGEST **ret_policy_digest);
int tpm2_policy_or(Tpm2Context *c, const Tpm2Handle *session, const TPM2B_DIGEST *branches, size_t n_branches, TPM2B_DIGEST **ret_policy_digest);
int tpm2_policy_super_pcr(Tpm2Context *c, const Tpm2Handle *session, const Tpm2PCRPrediction *prediction, uint16_t algorithm);
+int tpm2_policy_signed_hmac_sha256(Tpm2Context *c, const Tpm2Handle *session, const Tpm2Handle *hmac_key_handle, const struct iovec *hmac_key, TPM2B_DIGEST **ret_policy_digest);
int tpm2_calculate_pubkey_name(const TPMT_PUBLIC *public, TPM2B_NAME *ret_name);
int tpm2_calculate_nv_index_name(const TPMS_NV_PUBLIC *nvpublic, TPM2B_NAME *ret_name);
int tpm2_calculate_policy_pcr(const Tpm2PCRValue *pcr_values, size_t n_pcr_values, TPM2B_DIGEST *digest);
int tpm2_calculate_policy_or(const TPM2B_DIGEST *branches, size_t n_branches, TPM2B_DIGEST *digest);
int tpm2_calculate_policy_super_pcr(Tpm2PCRPrediction *prediction, uint16_t algorithm, TPM2B_DIGEST *pcr_policy);
+int tpm2_calculate_policy_signed(TPM2B_DIGEST *digest, const TPM2B_NAME *name);
int tpm2_calculate_serialize(TPM2_HANDLE handle, const TPM2B_NAME *name, const TPM2B_PUBLIC *public, void **ret_serialized, size_t *ret_serialized_size);
int tpm2_calculate_sealing_policy(const Tpm2PCRValue *pcr_values, size_t n_pcr_values, const TPM2B_PUBLIC *public, bool use_pin, const Tpm2PCRLockPolicy *policy, TPM2B_DIGEST *digest);
int tpm2_calculate_seal(TPM2_HANDLE parent_handle, const TPM2B_PUBLIC *parent_public, const TPMA_OBJECT *attributes, const struct iovec *secret, const TPM2B_DIGEST *policy, const char *pin, struct iovec *ret_secret, struct iovec *ret_blob, struct iovec *ret_serialized_parent);
int tpm2_load_public_key_file(const char *path, TPM2B_PUBLIC *ret);
+int tpm2_hmac_key_from_pin(Tpm2Context *c, const Tpm2Handle *session, const TPM2B_AUTH *pin, Tpm2Handle **ret);
+
/* The tpm2-tss library has many structs that are simply a combination of an array (or object) and
* size. These macros allow easily initializing or assigning instances of such structs from an existing
* buffer/object and size, while also checking the size for safety with the struct buffer/object size. If the
projects / thirdparty / systemd.git / commitdiff
