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Handle TPMs that lack SHA-1, disable EncryptDecrypt, or run a command longer than the TIS wait budget #607

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Handle TPMs that lack SHA-1, disable EncryptDecrypt, or run a command longer than the TIS wait budget #607

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869cf8f
Add native helpers to query algorithm and PCR bank support
dgarske Sep 15, 2026
d622cca
Reject oversized signatures before TPM2_VerifySignature
dgarske Sep 15, 2026
7b65adc
Skip example paths for features the TPM does not implement
dgarske Sep 15, 2026
627927c
Bound TIS wait loops by real time where a monotonic clock exists
dgarske Sep 15, 2026
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70 changes: 48 additions & 22 deletions examples/native/native_test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -339,6 +339,7 @@ int TPM2_Native_Test(void* userCtx)
int TPM2_Native_TestArgs(void* userCtx, int argc, char *argv[])
{
int rc;
int isAllocated = 0;
TPM2_CTX tpm2Ctx;

union {
Expand Down Expand Up @@ -863,22 +864,34 @@ int TPM2_Native_TestArgs(void* userCtx, int argc, char *argv[])
TPM2_PrintBin(cmdOut.policyGetDigest.policyDigest.buffer,
cmdOut.policyGetDigest.policyDigest.size);

/* Read PCR[0] SHA1 */
/* Many current TPMs allocate no SHA-1 bank; ask before selecting it. A
* query failure is reported, not silently treated as "no bank". */
pcrIndex = 0;
XMEMSET(&cmdIn.pcrRead, 0, sizeof(cmdIn.pcrRead));
TPM2_SetupPCRSel(&cmdIn.pcrRead.pcrSelectionIn, TPM_ALG_SHA1, pcrIndex);
rc = TPM2_PCR_Read(&cmdIn.pcrRead, &cmdOut.pcrRead);
rc = TPM2_IsPcrBankAllocated(TPM_ALG_SHA1, pcrIndex, &isAllocated);
if (rc != TPM_RC_SUCCESS) {
printf("TPM2_PCR_Read failed 0x%x: %s\n", rc,
printf("TPM2_IsPcrBankAllocated failed 0x%x: %s\n", rc,
TPM2_GetRCString(rc));
goto exit;
}
printf("TPM2_PCR_Read: Index %d, Digest Sz %d, Update Counter %d\n",
pcrIndex,
(int)cmdOut.pcrRead.pcrValues.digests[0].size,
(int)cmdOut.pcrRead.pcrUpdateCounter);
TPM2_PrintBin(cmdOut.pcrRead.pcrValues.digests[0].buffer,
cmdOut.pcrRead.pcrValues.digests[0].size);
if (!isAllocated) {
printf("TPM2_PCR_Read: SHA-1 skipped (no SHA-1 PCR bank allocated)\n");
}
else {
XMEMSET(&cmdIn.pcrRead, 0, sizeof(cmdIn.pcrRead));
TPM2_SetupPCRSel(&cmdIn.pcrRead.pcrSelectionIn, TPM_ALG_SHA1, pcrIndex);
rc = TPM2_PCR_Read(&cmdIn.pcrRead, &cmdOut.pcrRead);
if (rc != TPM_RC_SUCCESS) {
printf("TPM2_PCR_Read failed 0x%x: %s\n", rc,
TPM2_GetRCString(rc));
goto exit;
}
printf("TPM2_PCR_Read: Index %d, Digest Sz %d, Update Counter %d\n",
pcrIndex,
(int)cmdOut.pcrRead.pcrValues.digests[0].size,
(int)cmdOut.pcrRead.pcrUpdateCounter);
TPM2_PrintBin(cmdOut.pcrRead.pcrValues.digests[0].buffer,
cmdOut.pcrRead.pcrValues.digests[0].size);
}

#ifndef WOLFTPM2_NO_WOLFCRYPT
/* Set Auth Session index 0 */
Expand All @@ -892,20 +905,31 @@ int TPM2_Native_TestArgs(void* userCtx, int argc, char *argv[])
session[0].nonceCaller.size = TPM2_GetHashDigestSize(WOLFTPM2_WRAP_DIGEST);
session[0].auth = sessionAuth;

/* Policy PCR (Get) */
/* Policy PCR (Get). Selects the SHA-1 bank, so skip when unallocated. */
pcrIndex = 0;
XMEMSET(&cmdIn.policyPCR, 0, sizeof(cmdIn.policyPCR));
cmdIn.policyPCR.policySession = sessionHandle;
cmdIn.policyPCR.pcrDigest.size = 0;
TPM2_SetupPCRSel(&cmdIn.policyPCR.pcrs, TPM_ALG_SHA1, pcrIndex);
rc = TPM2_PolicyPCR(&cmdIn.policyPCR);
rc = TPM2_IsPcrBankAllocated(TPM_ALG_SHA1, pcrIndex, &isAllocated);
if (rc != TPM_RC_SUCCESS) {
printf("TPM2_PolicyPCR failed 0x%x: %s\n", rc,
printf("TPM2_IsPcrBankAllocated failed 0x%x: %s\n", rc,
TPM2_GetRCString(rc));
goto exit;
}
if (!isAllocated) {
printf("TPM2_PolicyPCR: SHA-1 skipped (no SHA-1 PCR bank allocated)\n");
}
else {
printf("TPM2_PolicyPCR: Updated\n");
XMEMSET(&cmdIn.policyPCR, 0, sizeof(cmdIn.policyPCR));
cmdIn.policyPCR.policySession = sessionHandle;
cmdIn.policyPCR.pcrDigest.size = 0;
TPM2_SetupPCRSel(&cmdIn.policyPCR.pcrs, TPM_ALG_SHA1, pcrIndex);
rc = TPM2_PolicyPCR(&cmdIn.policyPCR);
if (rc != TPM_RC_SUCCESS) {
printf("TPM2_PolicyPCR failed 0x%x: %s\n", rc,
TPM2_GetRCString(rc));
goto exit;
}
else {
printf("TPM2_PolicyPCR: Updated\n");
}
}
XMEMSET(&session[0], 0, sizeof(TPM2_AUTH_SESSION));
session[0].sessionHandle = TPM_RS_PW;
Expand Down Expand Up @@ -1635,7 +1659,7 @@ int TPM2_Native_TestArgs(void* userCtx, int argc, char *argv[])
cmdIn.encDec.decrypt = NO;
cmdIn.encDec.mode = TEST_AES_MODE;
rc = TPM2_EncryptDecrypt2(&cmdIn.encDec, &cmdOut.encDec);
if (WOLFTPM_IS_COMMAND_UNAVAILABLE(rc)) { /* some TPM's may not support command */
if (WOLFTPM_IS_COMMAND_UNAVAILABLE_OR_DISABLED(rc)) {
printf("TPM2_EncryptDecrypt2: Is not a supported feature without enabling due to export controls\n");
perform_EncryptDecrypt2 = 0;
rc = 0;
Expand All @@ -1657,7 +1681,9 @@ int TPM2_Native_TestArgs(void* userCtx, int argc, char *argv[])
cmdIn.encDec.decrypt = YES;
cmdIn.encDec.mode = TEST_AES_MODE;
rc = TPM2_EncryptDecrypt2(&cmdIn.encDec, &cmdOut.encDec);
if (rc == TPM_RC_COMMAND_CODE) { /* some TPM's may not support command */
if (WOLFTPM_IS_COMMAND_UNAVAILABLE_OR_DISABLED(rc)) {
/* Leave rc set: the check below inspects it to tell a real
* result from a skip, and cmdOut holds stale output. */
printf("TPM2_EncryptDecrypt2: Is not a supported feature without enabling due to export controls\n");
}
else if (rc != TPM_RC_SUCCESS) {
Expand All @@ -1673,7 +1699,7 @@ int TPM2_Native_TestArgs(void* userCtx, int argc, char *argv[])
cmdOut.encDec.outData.size) == 0) {
printf("Encrypt/Decrypt test success\n");
}
else if (WOLFTPM_IS_COMMAND_UNAVAILABLE(rc)) {
else if (WOLFTPM_IS_COMMAND_UNAVAILABLE_OR_DISABLED(rc)) {
printf("Encrypt/Decrypt test result allowed as pass since hardware doesn't support.\n");
rc = TPM_RC_SUCCESS;
}
Expand Down
11 changes: 11 additions & 0 deletions examples/pqc/pqc_ctrl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -493,6 +493,16 @@ static int do_hash_mldsa(WOLFTPM2_DEV* dev, TPMI_MLDSA_PARAMETER_SET ps)

rc = wolfTPM2_VerifyDigestSignature(dev, &key, digest, (int)sizeof(digest),
sig, sigSz, NULL, 0, &validation);
if (rc == BUFFER_E) {
/* Too large for this TPM to accept back for on-TPM verification.
* Signing worked but nothing checked it, so skip, not pass. Only
* BUFFER_E means oversize; a query error still reports FAIL. */
printf("SKIP HashML-DSA-%-3s signed %d bytes, not verified: "
"signature exceeds this TPM's input buffer\n",
mldsaName(ps), sigSz);
rc = TPM_RC_SUCCESS;
goto exit_quiet;
}
if (rc != TPM_RC_SUCCESS) goto exit;

if (validation.tag != TPM_ST_DIGEST_VERIFIED) {
Expand All @@ -510,6 +520,7 @@ static int do_hash_mldsa(WOLFTPM2_DEV* dev, TPMI_MLDSA_PARAMETER_SET ps)
printf("FAIL HashML-DSA-%-3s 0x%x: %s\n",
mldsaName(ps), rc, wolfTPM2_GetRCString(rc));
}
exit_quiet:
wolfTPM2_UnloadHandle(dev, &key.handle);
XFREE(sig, NULL, DYNAMIC_TYPE_TMP_BUFFER);
return rc;
Expand Down
37 changes: 23 additions & 14 deletions examples/wrap/wrap_test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,7 @@ int TPM2_Wrapper_Test(void* userCtx)
int TPM2_Wrapper_TestArgs(void* userCtx, int argc, char *argv[])
{
int rc, i;
int isSupported = 0;
WOLFTPM2_DEV dev;
WOLFTPM2_CAPS caps;
WOLFTPM2_KEY ekKey;
Expand Down Expand Up @@ -683,19 +684,27 @@ int TPM2_Wrapper_TestArgs(void* userCtx, int argc, char *argv[])
printf("ECC DH Test %s\n", rc == 0 ? "Passed" : "Failed");

/* ECC Public Key Signature Verify Test/Example */
rc = wolfTPM2_LoadEccPublicKey(&dev, &publicKey, TPM_ECC_NIST_P256,
kEccTestPubQX, sizeof(kEccTestPubQX),
kEccTestPubQY, sizeof(kEccTestPubQY));
/* Vector below uses a SHA-1 digest, which many current TPMs lack. */
rc = wolfTPM2_IsAlgSupported(&dev, TPM_ALG_SHA1, &isSupported);
if (rc != 0) goto exit;
if (!isSupported) {
printf("ECC Verify Test Skipped (TPM does not implement SHA-1)\n");
}
else {
rc = wolfTPM2_LoadEccPublicKey(&dev, &publicKey, TPM_ECC_NIST_P256,
kEccTestPubQX, sizeof(kEccTestPubQX),
kEccTestPubQY, sizeof(kEccTestPubQY));
if (rc != 0) goto exit;

rc = wolfTPM2_VerifyHashScheme(&dev, &publicKey,
kEccTestSigRS, sizeof(kEccTestSigRS),
kEccTestMsg, sizeof(kEccTestMsg), TPM_ALG_ECDSA, TPM_ALG_SHA1);
if (rc != 0) goto exit;
rc = wolfTPM2_VerifyHashScheme(&dev, &publicKey,
kEccTestSigRS, sizeof(kEccTestSigRS),
kEccTestMsg, sizeof(kEccTestMsg), TPM_ALG_ECDSA, TPM_ALG_SHA1);
if (rc != 0) goto exit;

rc = wolfTPM2_UnloadHandle(&dev, &publicKey.handle);
if (rc != 0) goto exit;
printf("ECC Verify Test Passed\n");
rc = wolfTPM2_UnloadHandle(&dev, &publicKey.handle);
if (rc != 0) goto exit;
printf("ECC Verify Test Passed\n");
}

/*------------------------------------------------------------------------*/
/* ECC KEY LOADING TESTS */
Expand Down Expand Up @@ -973,7 +982,7 @@ int TPM2_Wrapper_TestArgs(void* userCtx, int argc, char *argv[])
XMEMCPY(aesIv, TEST_AES_IV, (word32)sizeof(TEST_AES_IV));
rc = wolfTPM2_EncryptDecrypt(&dev, &aesKey, message.buffer, cipher.buffer,
message.size, aesIv, (word32)sizeof(aesIv), WOLFTPM2_ENCRYPT);
if (rc != 0 && !WOLFTPM_IS_COMMAND_UNAVAILABLE(rc)) goto exit;
if (rc != 0 && !WOLFTPM_IS_COMMAND_UNAVAILABLE_OR_DISABLED(rc)) goto exit;

XMEMSET(plain.buffer, 0, sizeof(plain.buffer));
plain.size = message.size;
Expand All @@ -990,7 +999,7 @@ int TPM2_Wrapper_TestArgs(void* userCtx, int argc, char *argv[])
XMEMCMP(cipher.buffer, TEST_AES_VERIFY, cipher.size) == 0) {
printf("Encrypt/Decrypt (known key) test success\n");
}
else if (WOLFTPM_IS_COMMAND_UNAVAILABLE(rc)) {
else if (WOLFTPM_IS_COMMAND_UNAVAILABLE_OR_DISABLED(rc)) {
printf("Encrypt/Decrypt: Is not a supported feature due to export controls\n");
}
else {
Expand Down Expand Up @@ -1020,7 +1029,7 @@ int TPM2_Wrapper_TestArgs(void* userCtx, int argc, char *argv[])
XMEMSET(aesIv, 0, sizeof(aesIv));
rc = wolfTPM2_EncryptDecrypt(&dev, &aesKey, message.buffer, cipher.buffer,
message.size, aesIv, (word32)sizeof(aesIv), WOLFTPM2_ENCRYPT);
if (rc != 0 && !WOLFTPM_IS_COMMAND_UNAVAILABLE(rc)) goto exit;
if (rc != 0 && !WOLFTPM_IS_COMMAND_UNAVAILABLE_OR_DISABLED(rc)) goto exit;

XMEMSET(plain.buffer, 0, sizeof(plain.buffer));
plain.size = message.size;
Expand All @@ -1035,7 +1044,7 @@ int TPM2_Wrapper_TestArgs(void* userCtx, int argc, char *argv[])
XMEMCMP(message.buffer, plain.buffer, message.size) == 0) {
printf("Encrypt/Decrypt test success\n");
}
else if (WOLFTPM_IS_COMMAND_UNAVAILABLE(rc)) {
else if (WOLFTPM_IS_COMMAND_UNAVAILABLE_OR_DISABLED(rc)) {
printf("Encrypt/Decrypt: Is not a supported feature due to export controls\n");
}
else {
Expand Down
82 changes: 82 additions & 0 deletions src/tpm2.c
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Expand Up @@ -7816,6 +7816,88 @@ void TPM2_PrintPublicArea(const TPM2B_PUBLIC* pub)
}
#endif /* DEBUG_WOLFTPM */

/* TPM_CAP_ALGS returns algorithms with ID >= property, so a match at index 0
* means implemented. Fails closed: *isSupported is 0 on any error. */
int TPM2_IsAlgSupported(TPM_ALG_ID alg, int* isSupported)
{
int rc;
GetCapability_In in;
GetCapability_Out out;
TPML_ALG_PROPERTY* algs;

if (isSupported == NULL) {
return BAD_FUNC_ARG;
}
*isSupported = 0;

XMEMSET(&in, 0, sizeof(in));
XMEMSET(&out, 0, sizeof(out));
in.capability = TPM_CAP_ALGS;
in.property = alg;
in.propertyCount = 1;
rc = TPM2_GetCapability(&in, &out);
if (rc != TPM_RC_SUCCESS) {
return rc; /* query failure, distinct from "not supported" */
}
/* union - confirm the capability asked for */
if (out.capabilityData.capability != TPM_CAP_ALGS) {
return TPM_RC_VALUE;
}

algs = &out.capabilityData.data.algorithms;
if (algs->count >= 1 && algs->algProperties[0].alg == alg) {
*isSupported = 1;
}
return TPM_RC_SUCCESS;
}

/* Implementing a hash and allocating a bank for it are separate: a TPM may
* offer SHA-1 while allocating no SHA-1 bank, and a selection naming an
* unallocated bank is rejected. Ask before TPM2_SetupPCRSel(). Fails closed. */
int TPM2_IsPcrBankAllocated(TPM_ALG_ID hashAlg, int pcrIndex, int* isAllocated)
{
int rc;
word32 i;
GetCapability_In in;
GetCapability_Out out;
TPML_PCR_SELECTION* banks;

if (isAllocated == NULL) {
return BAD_FUNC_ARG;
}
*isAllocated = 0;
if (pcrIndex < 0) {
return BAD_FUNC_ARG;
}

XMEMSET(&in, 0, sizeof(in));
XMEMSET(&out, 0, sizeof(out));
in.capability = TPM_CAP_PCRS;
in.property = 0;
in.propertyCount = HASH_COUNT; /* all assigned banks */
rc = TPM2_GetCapability(&in, &out);
if (rc != TPM_RC_SUCCESS) {
return rc;
}
if (out.capabilityData.capability != TPM_CAP_PCRS) {
return TPM_RC_VALUE;
}

banks = &out.capabilityData.data.assignedPCR;
for (i = 0; i < banks->count; i++) {
if (banks->pcrSelections[i].hash != hashAlg) {
continue;
}
if ((pcrIndex / 8) < (int)banks->pcrSelections[i].sizeofSelect &&
(banks->pcrSelections[i].pcrSelect[pcrIndex / 8] &
(1 << (pcrIndex % 8))) != 0) {
*isAllocated = 1;
break;
}
}
return TPM_RC_SUCCESS;
}

/******************************************************************************/
/* --- END Helpful API's -- */
/******************************************************************************/
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