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wrap: flush only the transient handles the TPM reports as loaded #666

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eac8cf2
wrap: flush only the transient handles the TPM reports as loaded
dgarske Nov 3, 2026
caa7cda
Follow TPM_CAP_HANDLES continuation and skip non-transient handles in…
dgarske Nov 3, 2026
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42 changes: 4 additions & 38 deletions examples/pqc/pqc_ctrl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -120,40 +120,6 @@ static const char* mlkemName(TPMI_MLKEM_PARAMETER_SET ps)
"768";
}

/* Reclaim the transient object table by flushing exactly the handles the TPM
* reports as loaded. Parts with a small object table (e.g. SealSQ QVault TPM)
* hit TPM_RC_OBJECT_MEMORY when a key plus a sign/verify sequence object are
* live at once. wolfTPM2_UnloadHandles_AllTransient() only covers
* MAX_HANDLE_NUM (3) fixed handles, so query the actual loaded set instead. */
static int pqc_flush_transient(WOLFTPM2_DEV* dev)
{
int rc;
word32 i;
GetCapability_In in;
GetCapability_Out out;
FlushContext_In flushCtx;

(void)dev; /* operates on the active TPM context */
XMEMSET(&in, 0, sizeof(in));
XMEMSET(&out, 0, sizeof(out));
XMEMSET(&flushCtx, 0, sizeof(flushCtx));
in.capability = TPM_CAP_HANDLES;
in.property = TRANSIENT_FIRST;
in.propertyCount = MAX_CAP_HANDLES;
rc = TPM2_GetCapability(&in, &out);
if (rc != TPM_RC_SUCCESS) {
return rc;
}
if (out.capabilityData.capability != TPM_CAP_HANDLES) {
return TPM_RC_FAILURE;
}
for (i = 0; i < out.capabilityData.data.handles.count; i++) {
flushCtx.flushHandle = out.capabilityData.data.handles.handle[i];
(void)TPM2_FlushContext(&flushCtx);
}
return TPM_RC_SUCCESS;
}

static int do_caps(WOLFTPM2_DEV* dev)
{
int rc;
Expand Down Expand Up @@ -401,7 +367,7 @@ static int do_mldsa(WOLFTPM2_DEV* dev, TPMI_MLDSA_PARAMETER_SET ps)
XMEMSET(&validation, 0, sizeof(validation));
XMEMSET(&flushCtx, 0, sizeof(flushCtx));

(void)pqc_flush_transient(dev);
(void)wolfTPM2_UnloadHandles_AllTransient(dev);

sig = (byte*)XMALLOC(MAX_MLDSA_SIG_SIZE, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (sig == NULL)
Expand Down Expand Up @@ -495,7 +461,7 @@ static int do_hash_mldsa(WOLFTPM2_DEV* dev, TPMI_MLDSA_PARAMETER_SET ps)
#endif
digestSz = TPM2_GetHashDigestSize(preHash);

(void)pqc_flush_transient(dev);
(void)wolfTPM2_UnloadHandles_AllTransient(dev);

sig = (byte*)XMALLOC(MAX_MLDSA_SIG_SIZE, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (sig == NULL)
Expand Down Expand Up @@ -571,7 +537,7 @@ static int do_mlkem(WOLFTPM2_DEV* dev, TPMI_MLKEM_PARAMETER_SET ps)
XMEMSET(ss1, 0, sizeof(ss1));
XMEMSET(ss2, 0, sizeof(ss2));

(void)pqc_flush_transient(dev);
(void)wolfTPM2_UnloadHandles_AllTransient(dev);

ct = (byte*)XMALLOC(MAX_MLKEM_CT_SIZE, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (ct == NULL)
Expand Down Expand Up @@ -721,7 +687,7 @@ static int handleOpt(WOLFTPM2_DEV* dev, const char* arg, int validateOnly)
if (validateOnly) {
return 0;
}
rc = pqc_flush_transient(dev);
rc = wolfTPM2_UnloadHandles_AllTransient(dev);
if (rc != TPM_RC_SUCCESS) {
printf("FAIL flush 0x%x: %s\n", rc, wolfTPM2_GetRCString(rc));
return rc;
Expand Down
50 changes: 49 additions & 1 deletion src/tpm2_wrap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9450,7 +9450,55 @@ int wolfTPM2_UnloadHandles(WOLFTPM2_DEV* dev, word32 handleStart,

int wolfTPM2_UnloadHandles_AllTransient(WOLFTPM2_DEV* dev)
{
return wolfTPM2_UnloadHandles(dev, TRANSIENT_FIRST, MAX_HANDLE_NUM);
int rc;
word32 i;
TPM_HANDLE next = TRANSIENT_FIRST;
GetCapability_In in;
GetCapability_Out out;
TPML_HANDLE* handles = &out.capabilityData.data.handles;
WOLFTPM2_HANDLE handle;

if (dev == NULL) {
return BAD_FUNC_ARG;
}

/* flush only the handles the TPM reports as loaded */
XMEMSET(&handle, 0, sizeof(handle));
wolfTPM2_CopyAuth(&handle.auth, &dev->session[0].auth);
for (;;) {
XMEMSET(&in, 0, sizeof(in));
in.capability = TPM_CAP_HANDLES;
in.property = next;
in.propertyCount = MAX_CAP_HANDLES;
rc = TPM2_GetCapability(&in, &out);
if (rc == TPM_RC_SUCCESS &&
out.capabilityData.capability != TPM_CAP_HANDLES) {
rc = TPM_RC_FAILURE;
}
if (rc != TPM_RC_SUCCESS) {
break;
}
for (i = 0; i < handles->count; i++) {
if (handles->handle[i] < next ||
(handles->handle[i] & HR_RANGE_MASK) != HR_TRANSIENT) {
break;
}
handle.hndl = handles->handle[i];
(void)wolfTPM2_UnloadHandle(dev, &handle);
next = handle.hndl + 1;
}
/* continue only after a non-empty page of ascending transient
* handles that reports more data */
if (!out.moreData || handles->count == 0 || i < handles->count) {
break;
}
}
TPM2_ForceZero(&handle, sizeof(handle));

if (rc != TPM_RC_SUCCESS && next == TRANSIENT_FIRST) {
return wolfTPM2_UnloadHandles(dev, TRANSIENT_FIRST, MAX_HANDLE_NUM);
}
return rc;
}

int wolfTPM2_ChangeHierarchyAuth(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* session,
Expand Down
31 changes: 31 additions & 0 deletions tests/unit_tests.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1866,6 +1866,36 @@ static void test_wolfTPM2_GetRandom(void)
rc == 0 ? "Passed" : "Failed");
}

static void test_wolfTPM2_UnloadHandles_AllTransient(void)
{
int rc;
WOLFTPM2_DEV dev;
WOLFTPM2_KEY srk;
int eccSupported = 0;

rc = wolfTPM2_Init(&dev, TPM2_IoCb, NULL);
AssertIntEQ(rc, 0);

rc = wolfTPM2_UnloadHandles_AllTransient(NULL);
AssertIntEQ(rc, BAD_FUNC_ARG);

AssertIntEQ(wolfTPM2_IsAlgSupported(&dev, TPM_ALG_ECC, &eccSupported), 0);
XMEMSET(&srk, 0, sizeof(srk));
rc = wolfTPM2_CreateSRK(&dev, &srk,
eccSupported ? TPM_ALG_ECC : TPM_ALG_RSA, NULL, 0);
AssertIntEQ(rc, 0);
AssertIntGE(wolfTPM2_GetHandles(TRANSIENT_FIRST, NULL), 1);

rc = wolfTPM2_UnloadHandles_AllTransient(&dev);
AssertIntEQ(rc, 0);
AssertIntEQ(wolfTPM2_GetHandles(TRANSIENT_FIRST, NULL), 0);

wolfTPM2_Cleanup(&dev);

printf("Test TPM Wrapper: %-40s %s\n", "Unload All Transient:",
rc == 0 ? "Passed" : "Failed");
}

static void test_wolfTPM2_HashFinish_BufferTooSmall(void)
{
#ifndef WOLFTPM2_NO_WOLFCRYPT
Expand Down Expand Up @@ -11847,6 +11877,7 @@ int unit_tests(int argc, char *argv[])
test_wolfTPM2_OpenExisting();
test_wolfTPM2_GetCapabilities();
test_wolfTPM2_GetRandom();
test_wolfTPM2_UnloadHandles_AllTransient();
test_wolfTPM2_DictionaryAttack();
test_wolfTPM2_HashFinish_BufferTooSmall();
test_TPM2_PCRSel();
Expand Down
1 change: 1 addition & 0 deletions wolftpm/tpm2_wrap.h
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Expand Up @@ -4042,6 +4042,7 @@ WOLFTPM_API int wolfTPM2_UnloadHandles(WOLFTPM2_DEV* dev, word32 handleStart,
/*!
\ingroup wolfTPM2_Wrappers
\brief One-shot API to unload all transient TPM handles
\note Flushes the transient handles the TPM reports as loaded, following TPM_CAP_HANDLES continuation pages, or the first MAX_HANDLE_NUM if the first TPM_CAP_HANDLES query fails
\note If there are Primary Keys as transient objects, they need to be recreated before TPM keys can be used

\return TPM_RC_SUCCESS: successful
Expand Down
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