SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

tpm2: add tpm2_policy_pcr()

Browse Source 
This adds functions to get the digest for a PolicyPCR operation. For building
a policy hash, this provides a function to calculate the hash; and for building
a policy hash to satisfy the authPolicy for an existing object, this provides a
function to perform PolicyPCR with an existing session.
This commit is contained in:
Dan Streetman
2023-05-26 11:11:25 -04:00
parent c648a4b85e
commit dcbc4674e3
3 changed files with 143 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/shared/tpm2-util.c
+92 -27
View File
@@ -64,10 +64,12 @@ TSS2_RC (*sym_Esys_VerifySignature)(ESYS_CONTEXT *esysContext, ESYS_TR keyHandle
const char* (*sym_Tss2_RC_Decode)(TSS2_RC rc) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2_CC_Marshal)(TPM2_CC src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Marshal)(TPM2B_PRIVATE const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PRIVATE *dest) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Marshal)(TPM2B_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PUBLIC *dest) = NULL;
TSS2_RC (*sym_Tss2_MU_TPML_PCR_SELECTION_Marshal)(TPML_PCR_SELECTION const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
TSS2_RC (*sym_Tss2_MU_TPMT_HA_Marshal)(TPMT_HA const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
TSS2_RC (*sym_Tss2_MU_TPMT_PUBLIC_Marshal)(TPMT_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
@@ -116,10 +118,12 @@ int dlopen_tpm2(void) {
return dlopen_many_sym_or_warn(
&libtss2_mu_dl, "libtss2-mu.so.0", LOG_DEBUG,
DLSYM_ARG(Tss2_MU_TPM2_CC_Marshal),
DLSYM_ARG(Tss2_MU_TPM2B_PRIVATE_Marshal),
DLSYM_ARG(Tss2_MU_TPM2B_PRIVATE_Unmarshal),
DLSYM_ARG(Tss2_MU_TPM2B_PUBLIC_Marshal),
DLSYM_ARG(Tss2_MU_TPM2B_PUBLIC_Unmarshal),
DLSYM_ARG(Tss2_MU_TPML_PCR_SELECTION_Marshal),
DLSYM_ARG(Tss2_MU_TPMT_HA_Marshal),
DLSYM_ARG(Tss2_MU_TPMT_PUBLIC_Marshal));
}
@@ -1929,6 +1933,90 @@ static int tpm2_get_name(
return 0;
}
/* Extend 'digest' with the PolicyPCR calculated hash. */
int tpm2_calculate_policy_pcr(
const TPML_PCR_SELECTION *pcr_selection,
const TPM2B_DIGEST pcr_values[],
size_t n_pcr_values,
TPM2B_DIGEST *digest) {
TPM2_CC command = TPM2_CC_PolicyPCR;
TSS2_RC rc;
int r;
assert(pcr_selection);
assert(pcr_values || n_pcr_values == 0);
assert(digest);
assert(digest->size == SHA256_DIGEST_SIZE);
r = dlopen_tpm2();
if (r < 0)
return log_error_errno(r, "TPM2 support not installed: %m");
TPM2B_DIGEST hash = {};
r = tpm2_digest_many_digests(TPM2_ALG_SHA256, &hash, pcr_values, n_pcr_values, /* extend= */ false);
if (r < 0)
return r;
_cleanup_free_ uint8_t *buf = NULL;
size_t size = 0, maxsize = sizeof(command) + sizeof(*pcr_selection);
buf = malloc(maxsize);
if (!buf)
return log_oom();
rc = sym_Tss2_MU_TPM2_CC_Marshal(command, buf, maxsize, &size);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to marshal PolicyPCR command: %s", sym_Tss2_RC_Decode(rc));
rc = sym_Tss2_MU_TPML_PCR_SELECTION_Marshal(pcr_selection, buf, maxsize, &size);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to marshal PCR selection: %s", sym_Tss2_RC_Decode(rc));
struct iovec data[] = {
IOVEC_MAKE(buf, size),
IOVEC_MAKE(hash.buffer, hash.size),
};
r = tpm2_digest_many(TPM2_ALG_SHA256, digest, data, ELEMENTSOF(data), /* extend= */ true);
if (r < 0)
return r;
tpm2_log_debug_digest(digest, "PolicyPCR calculated digest");
return 0;
}
static int tpm2_policy_pcr(
Tpm2Context *c,
const Tpm2Handle *session,
const TPML_PCR_SELECTION *pcr_selection,
TPM2B_DIGEST **ret_policy_digest) {
TSS2_RC rc;
assert(c);
assert(session);
assert(pcr_selection);
log_debug("Adding PCR hash policy.");
rc = sym_Esys_PolicyPCR(
c->esys_context,
session->esys_handle,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
NULL,
pcr_selection);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to add PCR policy to TPM: %s", sym_Tss2_RC_Decode(rc));
return tpm2_get_policy_digest(c, session, ret_policy_digest);
}
static int tpm2_build_sealing_policy(
Tpm2Context *c,
const Tpm2Handle *session,
@@ -2004,21 +2092,8 @@ static int tpm2_build_sealing_policy(
/* Put together the PCR policy we want to use */
TPML_PCR_SELECTION pcr_selection;
tpm2_tpml_pcr_selection_from_mask(pubkey_pcr_mask, (TPMI_ALG_HASH)pcr_bank, &pcr_selection);
rc = sym_Esys_PolicyPCR(
c->esys_context,
session->esys_handle,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
NULL,
&pcr_selection);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to add PCR policy to TPM: %s", sym_Tss2_RC_Decode(rc));
/* Get the policy hash of the PCR policy */
_cleanup_(Esys_Freep) TPM2B_DIGEST *approved_policy = NULL;
r = tpm2_get_policy_digest(c, session, &approved_policy);
r = tpm2_policy_pcr(c, session, &pcr_selection, &approved_policy);
if (r < 0)
return r;
@@ -2098,21 +2173,11 @@ static int tpm2_build_sealing_policy(
}
if (hash_pcr_mask != 0) {
log_debug("Configuring hash-based PCR policy.");
TPML_PCR_SELECTION pcr_selection;
tpm2_tpml_pcr_selection_from_mask(hash_pcr_mask, (TPMI_ALG_HASH)pcr_bank, &pcr_selection);
rc = sym_Esys_PolicyPCR(
c->esys_context,
session->esys_handle,
ESYS_TR_NONE,
ESYS_TR_NONE,
ESYS_TR_NONE,
NULL,
&pcr_selection);
if (rc != TSS2_RC_SUCCESS)
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
"Failed to add PCR policy to TPM: %s", sym_Tss2_RC_Decode(rc));
r = tpm2_policy_pcr(c, session, &pcr_selection, NULL);
if (r < 0)
return r;
}
if (use_pin) {
src/shared/tpm2-util.h
+3
View File
@@ -66,10 +66,12 @@ extern TSS2_RC (*sym_Esys_VerifySignature)(ESYS_CONTEXT *esysContext, ESYS_TR ke
extern const char* (*sym_Tss2_RC_Decode)(TSS2_RC rc);
extern TSS2_RC (*sym_Tss2_MU_TPM2_CC_Marshal)(TPM2_CC src, uint8_t buffer[], size_t buffer_size, size_t *offset);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Marshal)(TPM2B_PRIVATE const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PRIVATE *dest);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Marshal)(TPM2B_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
extern TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PUBLIC *dest);
extern TSS2_RC (*sym_Tss2_MU_TPML_PCR_SELECTION_Marshal)(TPML_PCR_SELECTION const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
extern TSS2_RC (*sym_Tss2_MU_TPMT_HA_Marshal)(TPMT_HA const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
extern TSS2_RC (*sym_Tss2_MU_TPMT_PUBLIC_Marshal)(TPMT_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
@@ -88,6 +90,7 @@ static inline int tpm2_digest_init(TPMI_ALG_HASH alg, TPM2B_DIGEST *digest) {
}
int tpm2_calculate_name(const TPMT_PUBLIC *public, TPM2B_NAME *ret_name);
int tpm2_calculate_policy_pcr(const TPML_PCR_SELECTION *pcr_selection, const TPM2B_DIGEST pcr_values[], size_t pcr_values_count, TPM2B_DIGEST *digest);
int tpm2_seal(const char *device, uint32_t hash_pcr_mask, const void *pubkey, size_t pubkey_size, uint32_t pubkey_pcr_mask, const char *pin, void **ret_secret, size_t *ret_secret_size, void **ret_blob, size_t *ret_blob_size, void **ret_pcr_hash, size_t *ret_pcr_hash_size, uint16_t *ret_pcr_bank, uint16_t *ret_primary_alg, void **ret_srk_buf, size_t *ret_srk_buf_size);
int tpm2_unseal(const char *device, uint32_t hash_pcr_mask, uint16_t pcr_bank, const void *pubkey, size_t pubkey_size, uint32_t pubkey_pcr_mask, JsonVariant *signature, const char *pin, uint16_t primary_alg, const void *blob, size_t blob_size, const void *policy_hash, size_t policy_hash_size, const void *srk_buf, size_t srk_buf_size, void **ret_secret, size_t *ret_secret_size);