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policy: Support TPMLess commands #2762

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policy: Support TPMLess commands #2762

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100 changes: 100 additions & 0 deletions lib/tpm2.c
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Original file line number Diff line number Diff line change
Expand Up @@ -685,6 +685,106 @@ tool_rc tpm2_policy_countertimer(ESYS_CONTEXT *esys_context,
return tool_rc_success;
}

static tool_rc policy_update(TPMI_ALG_HASH halg, TPM2_CC cc, TPM2B_NAME *name, TPM2B_DIGEST *old, TPM2B_NONCE *ref, TPM2B_DIGEST *new) {

tool_rc result = tool_rc_general_error;
const EVP_MD *md = tpm2_openssl_halg_from_tpmhalg(halg);
if (!md) {
LOG_ERR("Could not find digester for algorithm 0x%x", halg);
return tool_rc_general_error;
}

EVP_MD_CTX *mdctx = EVP_MD_CTX_create();
if (!mdctx) {
LOG_ERR("%s", tpm2_openssl_get_err());
return tool_rc_general_error;
}

int rc = EVP_DigestInit_ex(mdctx, md, NULL);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}

rc = EVP_DigestUpdate(mdctx, old->buffer, old->size);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}

TPM2_CC becc = tpm2_util_hton_32(cc);
rc = EVP_DigestUpdate(mdctx, &becc, sizeof(becc));
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}

if (name) {
rc = EVP_DigestUpdate(mdctx, name->name, name->size);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}
}

unsigned size = EVP_MD_size(md);
rc = EVP_DigestFinal_ex(mdctx, new->buffer, &size);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}
/* hash sizes are not bigger than 16 bits, safe truncate */
new->size = (UINT16)size;

if(ref) {
mdctx = EVP_MD_CTX_create();
if (!mdctx) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}

rc = EVP_DigestInit_ex(mdctx, md, NULL);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}

rc = EVP_DigestUpdate(mdctx, new->buffer, new->size);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}

rc = EVP_DigestUpdate(mdctx, ref->buffer, ref->size);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}

unsigned size = EVP_MD_size(md);
rc = EVP_DigestFinal_ex(mdctx, new->buffer, &size);
if (!rc) {
LOG_ERR("%s", tpm2_openssl_get_err());
goto out;
}
/* hash sizes are not bigger than 16 bits, safe truncate */
new->size = (UINT16)size;
}

result = tool_rc_success;

out:
EVP_MD_CTX_destroy(mdctx);
return result;
}


tool_rc tpm2_policy_secret_no_tpm(TPMI_ALG_HASH halg, TPM2B_DIGEST *current, TPM2B_NAME *name, TPM2B_NONCE *policy_qualifier,
TPMT_TK_AUTH *new) {

return policy_update(halg, TPM2_CC_PolicySecret, name, current, policy_qualifier, &new->digest);
}

tool_rc tpm2_policy_secret(ESYS_CONTEXT *esys_context,
tpm2_loaded_object *auth_entity_obj, ESYS_TR policy_session,
INT32 expiration, TPMT_TK_AUTH **policy_ticket,
Expand Down
3 changes: 3 additions & 0 deletions lib/tpm2.h
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Original file line number Diff line number Diff line change
Expand Up @@ -117,6 +117,9 @@ tool_rc tpm2_policy_ticket(ESYS_CONTEXT *esys_context, ESYS_TR policy_session,
tool_rc tpm2_policy_authvalue(ESYS_CONTEXT *esys_context, ESYS_TR policy_session,
ESYS_TR shandle1, ESYS_TR shandle2, ESYS_TR shandle3);

tool_rc tpm2_policy_secret_no_tpm(TPMI_ALG_HASH halg, TPM2B_DIGEST *current, TPM2B_NAME *name, TPM2B_NONCE *policy_qualifier,
TPMT_TK_AUTH *new);

tool_rc tpm2_policy_secret(ESYS_CONTEXT *esys_context,
tpm2_loaded_object *auth_entity_obj, ESYS_TR policy_session,
INT32 expiration, TPMT_TK_AUTH **policy_ticket,
Expand Down
24 changes: 24 additions & 0 deletions lib/tpm2_policy.c
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Original file line number Diff line number Diff line change
Expand Up @@ -309,6 +309,30 @@ tool_rc tpm2_policy_build_policysecret(ESYS_CONTEXT *ectx,
}
}

if (!ectx || true) {
if (is_nonce_tpm) {
LOG_ERR("Cannot specify is_nonce_tpm with NULL ESYS Context");
return tool_rc_general_error;
}
/* TODO: Get old from input file -L */
TPM2B_DIGEST old = { 0 };
old.size = 32;
/* TODO get name, not hardcoded! */
TPM2B_NAME name ={
.size = 4,
.name = { 0x40, 0x00, 0x00, 0x01 }
};
/* TODO get halg */
/* TODO This needs to be tied to Esys_Malloc.... but that doesn't exist */
TPMT_TK_AUTH *pt = calloc(sizeof(*pt), 1);
/* TODO error check */
tool_rc rc = tpm2_policy_secret_no_tpm(TPM2_ALG_SHA256, &old, &name, &policy_qualifier, pt);
if (rc == tool_rc_success) {
*policy_ticket = pt;
}
return rc;
}

ESYS_TR policy_session_handle = tpm2_session_get_handle(policy_session);

TPM2B_NONCE *nonce_tpm = NULL;
Expand Down