From 580b3a779ea203f217ea65ea6cbed2bd23cb5701 Mon Sep 17 00:00:00 2001
From: David Garske <david@wolfssl.com>
Date: Tue, 10 Dec 2024 15:32:18 -0800
Subject: [PATCH 1/3] Fix issue with session binding. Add example for NV extend
 based on the TCG "bus protection guidance".

---
 examples/gpio/gpio_config.c |   2 +-
 examples/nvram/extend.c     | 327 ++++++++++++++++++++++++++++++++++++
 examples/nvram/include.am   |  18 +-
 examples/nvram/nvram.h      |   1 +
 examples/nvram/read.c       | 126 ++++++++------
 examples/nvram/store.c      |  28 +--
 examples/run_examples.sh    |  41 +++--
 examples/tpm_test.h         |   1 +
 src/tpm2.c                  |   3 +
 src/tpm2_param_enc.c        |  92 +++++++---
 src/tpm2_wrap.c             |  75 ++++++---
 wolftpm/tpm2.h              |   3 +-
 wolftpm/tpm2_wrap.h         |  25 +++
 13 files changed, 609 insertions(+), 133 deletions(-)
 create mode 100644 examples/nvram/extend.c

diff --git a/examples/gpio/gpio_config.c b/examples/gpio/gpio_config.c
index 189d3d73..4be4d4b1 100644
--- a/examples/gpio/gpio_config.c
+++ b/examples/gpio/gpio_config.c
@@ -406,7 +406,7 @@ int TPM2_GPIO_Config_Example(void* userCtx, int argc, char *argv[])
     rc = wolfTPM2_GetNvAttributesTemplate(parent.hndl, &nvAttributes);
     /* Add NV attributes required by Nuvoton specification */
     nvAttributes |= (TPMA_NV_PLATFORMCREATE | TPMA_NV_POLICY_DELETE);
-    nvAttributes |= (TPM_NT_ORDINARY & TPMA_NV_TPM_NT);
+    nvAttributes |= (TPMA_NV_TPM_NT & (TPM_NT_ORDINARY << 4));
     if (rc != TPM_RC_SUCCESS) {
         printf("Setting NV attributes failed\n");
         goto exit;
diff --git a/examples/nvram/extend.c b/examples/nvram/extend.c
new file mode 100644
index 00000000..1b147b42
--- /dev/null
+++ b/examples/nvram/extend.c
@@ -0,0 +1,327 @@
+/* extend.c
+ *
+ * Copyright (C) 2006-2024 wolfSSL Inc.
+ *
+ * This file is part of wolfTPM.
+ *
+ * wolfTPM is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfTPM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+/* Example for showing NV extend usage for bus protection:
+* See "TCG_-CPU_-TPM_Bus_Protection_Guidance_Active_Attack_Mitigations-V1-R30_PUB-1.pdf" */
+
+#ifdef HAVE_CONFIG_H
+    #include <config.h>
+#endif
+
+#include <wolftpm/tpm2_wrap.h>
+#include <stdio.h>
+
+#ifndef WOLFTPM2_NO_WRAPPER
+
+#include <examples/nvram/nvram.h>
+#include <hal/tpm_io.h>
+#include <examples/tpm_test.h>
+#include <examples/tpm_test_keys.h>
+
+/******************************************************************************/
+/* --- BEGIN TPM NVRAM Extend Example -- */
+/******************************************************************************/
+static void usage(void)
+{
+    printf("Expected usage:\n");
+    printf("./examples/nvram/extend [-nvindex=handle] [-aes/-xor]\n");
+    printf("* -nvindex=[handle] (default 0x%x)\n",
+        TPM2_DEMO_NVRAM_EXTEND_INDEX);
+    printf("* -aes/xor: Use Parameter Encryption\n");;
+}
+
+/* Policy A: TPM2_PolicyCommandCode -> TPM_CC_NV_Read */
+static const byte policyA[] = {
+    0x47, 0xCE, 0x30, 0x32, 0xD8, 0xBA, 0xD1, 0xF3,
+    0x08, 0x9C, 0xB0, 0xC0, 0x90, 0x88, 0xDE, 0x43,
+    0x50, 0x14, 0x91, 0xD4, 0x60, 0x40, 0x2B, 0x90,
+    0xCD, 0x1B, 0x7F, 0xC0, 0xB6, 0x8C, 0xA9, 0x2F
+};
+/* Policy B: TPM2_PolicyCommandCode -> TPM_CC_NV_Extend */
+static const byte policyB[] = {
+    0xB6, 0xA2, 0xE7, 0x14, 0x2E, 0xE5, 0x6F, 0xD9,
+    0x78, 0x04, 0x74, 0x88, 0x48, 0x3D, 0xAA, 0x5B,
+    0x42, 0xB8, 0xDC, 0x4C, 0xC7, 0xDD, 0xCC, 0xED,
+    0xDF, 0xB9, 0x17, 0x93, 0xCF, 0x1F, 0xF1, 0xB7
+};
+/* Policy C: TPM2_PolicyCommandCode -> TPM_CC_PolicyNV */
+static const byte policyC[] = {
+    0x20, 0x3E, 0x4B, 0xD5, 0xD0, 0x44, 0x8C, 0x96,
+    0x15, 0xCC, 0x13, 0xFA, 0x18, 0xE8, 0xD3, 0x92,
+    0x22, 0x44, 0x1C, 0xC4, 0x02, 0x04, 0xD9, 0x9A,
+    0x77, 0x26, 0x20, 0x68, 0xDB, 0xD5, 0x5A, 0x43
+};
+
+/* pre-computed policy:
+ * NV Read (A), NV Extend (B), PolicyNV (C), then policy OR (A/B/C) */
+static const byte policyNv[] = {
+    0x7F, 0x17, 0x93, 0x7E, 0x20, 0x62, 0x79, 0xA3,
+    0xF7, 0x55, 0xFB, 0x60, 0xF4, 0x0C, 0xF1, 0x26,
+    0xB7, 0x0E, 0x5B, 0x1D, 0x9B, 0xF2, 0x02, 0x86,
+    0x6D, 0x52, 0x76, 0x13, 0x87, 0x4A, 0x64, 0xAC
+};
+
+
+static int PolicyOrApply(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* policySession)
+{
+    PolicyOR_In policyOR;
+    XMEMSET(&policyOR, 0, sizeof(policyOR));
+    policyOR.policySession = policySession->handle.hndl;
+    policyOR.pHashList.count = 3;
+    policyOR.pHashList.digests[0].size = sizeof(policyA);
+    XMEMCPY(policyOR.pHashList.digests[0].buffer, policyA, sizeof(policyA));
+    policyOR.pHashList.digests[1].size = sizeof(policyB);
+    XMEMCPY(policyOR.pHashList.digests[1].buffer, policyB, sizeof(policyB));
+    policyOR.pHashList.digests[2].size = sizeof(policyC);
+    XMEMCPY(policyOR.pHashList.digests[2].buffer, policyC, sizeof(policyC));
+    (void)dev;
+    return TPM2_PolicyOR(&policyOR);
+}
+
+int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
+{
+    int rc;
+    WOLFTPM2_DEV dev;
+    WOLFTPM2_KEY endorse;
+    WOLFTPM2_SESSION tpmSession;
+    WOLFTPM2_HANDLE nvAuth;
+    WOLFTPM2_HANDLE bind;
+    WOLFTPM2_NV nv;
+    word32 nvAttributes;
+    int paramEncAlg = TPM_ALG_CFB;
+    TPMI_RH_NV_AUTH authHandle = TPM_RH_PLATFORM;
+    word32 nvIndex = TPM2_DEMO_NVRAM_EXTEND_INDEX;
+    word32 nvSize; /* 32 for SHA2-256 */
+    byte*  auth = (byte*)"cpusecret";
+    word32 authSz = (word32)XSTRLEN((const char*)auth);
+    byte   nvDigest[32];
+    word32 nvDigestSz = (word32)sizeof(nvDigest);
+
+    if (argc >= 2) {
+        if (XSTRCMP(argv[1], "-?") == 0 ||
+            XSTRCMP(argv[1], "-h") == 0 ||
+            XSTRCMP(argv[1], "--help") == 0) {
+            usage();
+            return 0;
+        }
+    }
+    while (argc > 1) {
+        if (XSTRNCMP(argv[argc-1], "-nvindex=", XSTRLEN("-nvindex=")) == 0) {
+            const char* nvIndexStr = argv[argc-1] + XSTRLEN("-nvindex=");
+            nvIndex = (word32)XSTRTOUL(nvIndexStr, NULL, 0);
+            if (nvIndex >= TPM_20_PLATFORM_MFG_NV_SPACE &&
+                nvIndex <  TPM_20_OWNER_NV_SPACE) {
+                authHandle = TPM_RH_PLATFORM;
+            }
+            else if (nvIndex >= TPM_20_OWNER_NV_SPACE &&
+                     nvIndex <  TPM_20_TCG_NV_SPACE) {
+                authHandle = TPM_RH_OWNER;
+            }
+            else {
+                fprintf(stderr, "Invalid NV Index %s\n", nvIndexStr);
+                fprintf(stderr, "\tPlatform Range: 0x%x -> 0x%x\n",
+                    TPM_20_PLATFORM_MFG_NV_SPACE, TPM_20_OWNER_NV_SPACE);
+                fprintf(stderr, "\tOwner Range: 0x%x -> 0x%x\n",
+                    TPM_20_OWNER_NV_SPACE, TPM_20_TCG_NV_SPACE);
+                usage();
+                return -1;
+            }
+        }
+        else if (XSTRCMP(argv[argc-1], "-aes") == 0) {
+            paramEncAlg = TPM_ALG_CFB;
+        }
+        else if (XSTRCMP(argv[argc-1], "-xor") == 0) {
+            paramEncAlg = TPM_ALG_XOR;
+        }
+        else {
+            printf("Warning: Unrecognized option: %s\n", argv[argc-1]);
+        }
+        argc--;
+    };
+
+    printf("NVRAM Extend (bus protection example)\n");
+    printf("Parameter Encryption: %s\n",
+        (paramEncAlg == TPM_ALG_CFB) ? "AES CFB" : "XOR");
+
+    XMEMSET(&tpmSession, 0, sizeof(tpmSession));
+    XMEMSET(&endorse, 0, sizeof(endorse));
+    XMEMSET(&bind, 0, sizeof(bind));
+    XMEMSET(&nv, 0, sizeof(nv));
+    XMEMSET(&nvAuth, 0, sizeof(nvAuth));
+
+    rc = wolfTPM2_Init(&dev, TPM2_IoCb, userCtx);
+    if (rc != TPM_RC_SUCCESS) {
+        printf("wolfTPM2_Init failed\n");
+        goto exit;
+    }
+
+    /* 1: Create EK RSA 2048-bit */
+    rc = wolfTPM2_CreateEK(&dev, &endorse, TPM_ALG_RSA);
+    if (rc != 0) {
+        printf("Create EK RSA failed!\n");
+        goto exit;
+    }
+    endorse.handle.policyAuth = 1; /* EK requires policy auth */
+    printf("EK Handle: 0x%x\n", (word32)endorse.handle.hndl);
+
+    /* 2: Create a salted session with the TPM using the EK */
+    rc = wolfTPM2_StartSession(&dev, &tpmSession, &endorse, NULL,
+        TPM_SE_HMAC, paramEncAlg);
+    if (rc == 0) {
+        rc = wolfTPM2_SetAuthSession(&dev, 0, &tpmSession,
+            (TPMA_SESSION_decrypt | TPMA_SESSION_encrypt |
+             TPMA_SESSION_continueSession));
+    }
+    if (rc != 0) {
+        printf("Start HMAC session failed!\n");
+        goto exit;
+    }
+    printf("Encrypted HMAC Session Handle 0x%x\n",
+        (word32)tpmSession.handle.hndl);
+
+    /* 3. Create the NV Index with extend attribute.
+     * Use "host secret" as password so it is used with the bind session later */
+
+    /* See TPM_Bus_Protection_Guidance_Active_Attack_Mitigations:
+     * Section 3.4 Provisioning the NV Index */
+    nvAttributes = (
+            (TPMA_NV_TPM_NT & (TPM_NT_EXTEND << 4)) |
+            TPMA_NV_ORDERLY |
+            TPMA_NV_CLEAR_STCLEAR |
+            TPMA_NV_PLATFORMCREATE |
+            TPMA_NV_POLICYWRITE |
+            TPMA_NV_POLICYREAD |
+            TPMA_NV_NO_DA);
+    nvSize = TPM2_GetHashDigestSize(WOLFTPM2_WRAP_DIGEST);
+
+    /* Try and open existing NV */
+    rc = wolfTPM2_NVOpen(&dev, &nv, nvIndex, auth, authSz);
+    if (rc != 0) {
+        nvAuth.hndl = authHandle;
+
+        rc = wolfTPM2_NVCreateAuthPolicy(&dev, &nvAuth, &nv, nvIndex,
+            nvAttributes, /* needs TPM_NT_EXTEND set */
+            nvSize, /* must match nameAlg digest size */
+            auth, authSz, /* the password to bind session with */
+            policyNv, (word32)sizeof(policyNv)
+        );
+    }
+
+    /* Close session and unload endorsement */
+    wolfTPM2_UnsetAuth(&dev, 0);
+    wolfTPM2_UnloadHandle(&dev, &tpmSession.handle);
+    wolfTPM2_UnloadHandle(&dev, &endorse.handle);
+
+
+    /* 4. Start a policy session and bind to NV handle */
+    rc = wolfTPM2_StartSession(&dev, &tpmSession, NULL, &nv.handle,
+        TPM_SE_POLICY, TPM_ALG_CFB);
+    if (rc == 0) {
+        rc = wolfTPM2_SetAuthSession(&dev, 0, &tpmSession,
+            (TPMA_SESSION_decrypt | TPMA_SESSION_encrypt |
+             TPMA_SESSION_continueSession));
+    }
+    if (rc != 0) {
+        printf("Start Policy session failed!\n");
+        goto exit;
+    }
+    printf("Encrypted Policy Session Handle 0x%x\n",
+        (word32)tpmSession.handle.hndl);
+
+    /* 5. Satisfy policy for NV Extend (policy B) */
+    rc = wolfTPM2_PolicyCommandCode(&dev, &tpmSession, TPM_CC_NV_Extend);
+    if (rc == 0) {
+        rc = PolicyOrApply(&dev, &tpmSession);
+    }
+    if (rc != 0) {
+        printf("Failed to apply policy B\n");
+        goto exit;
+    }
+
+    /* 6. Perform NV extend */
+    rc = wolfTPM2_NVExtend(&dev, &nv, nvIndex, auth, (word32)authSz);
+    if (rc != 0) {
+        printf("NV Extend failed!\n");
+        goto exit;
+    }
+    printf("NV 0x%08x extended\n", (word32)nvIndex);
+
+    /* 7. Restart session policy */
+    rc = wolfTPM2_PolicyRestart(&dev, tpmSession.handle.hndl);
+    if (rc != 0) {
+        printf("Policy restart failed!\n");
+        goto exit;
+    }
+
+    /* 8. Satisfy policy for NV Read (policy A) */
+    rc = wolfTPM2_PolicyCommandCode(&dev, &tpmSession, TPM_CC_NV_Read);
+    if (rc == 0) {
+        rc = PolicyOrApply(&dev, &tpmSession);
+    }
+    if (rc != 0) {
+        printf("Failed to apply policy A\n");
+        goto exit;
+    }
+
+    /* 9. Read NV extend digest */
+    rc = wolfTPM2_NVRead(&dev, authHandle, nv.handle.hndl,
+        nvDigest, &nvDigestSz, 0);
+    if (rc == 0) {
+        printf("NV Digest: %d\n", nvDigestSz);
+        TPM2_PrintBin(nvDigest, nvDigestSz);
+
+        /* Should be:
+         * 0ad80f8e4450587760d9137df41c9374f657bafa621fe37d4d5c8cecf0bcce5e */
+    }
+
+exit:
+
+    if (rc != 0) {
+        printf("\nFailure 0x%x: %s\n\n", rc, wolfTPM2_GetRCString(rc));
+    }
+
+    wolfTPM2_UnloadHandle(&dev, &tpmSession.handle);
+    wolfTPM2_Cleanup(&dev);
+
+    return rc;
+}
+
+/******************************************************************************/
+/* --- END TPM NVRAM Extend Example -- */
+/******************************************************************************/
+#endif /* !WOLFTPM2_NO_WRAPPER */
+
+#ifndef NO_MAIN_DRIVER
+int main(int argc, char *argv[])
+{
+    int rc = NOT_COMPILED_IN;
+
+#ifndef WOLFTPM2_NO_WRAPPER
+    rc = TPM2_NVRAM_Extend_Example(NULL, argc, argv);
+#else
+    printf("NVRAM code not compiled in\n");
+    (void)argc;
+    (void)argv;
+#endif
+
+    return rc;
+}
+#endif
diff --git a/examples/nvram/include.am b/examples/nvram/include.am
index 4e8146aa..4e1d5e0f 100644
--- a/examples/nvram/include.am
+++ b/examples/nvram/include.am
@@ -27,6 +27,12 @@ examples_nvram_policy_nv_SOURCES      = examples/nvram/policy_nv.c \
                                         examples/tpm_test_keys.c
 examples_nvram_policy_nv_LDADD        = src/libwolftpm.la $(LIB_STATIC_ADD)
 examples_nvram_policy_nv_DEPENDENCIES = src/libwolftpm.la
+
+noinst_PROGRAMS += examples/nvram/extend
+examples_nvram_extend_SOURCES      = examples/nvram/extend.c \
+                                     examples/tpm_test_keys.c
+examples_nvram_extend_LDADD        = src/libwolftpm.la $(LIB_STATIC_ADD)
+examples_nvram_extend_DEPENDENCIES = src/libwolftpm.la
 endif
 
 example_nvramdir = $(exampledir)/nvram
@@ -34,9 +40,11 @@ dist_example_nvram_DATA = \
   examples/nvram/store.c \
   examples/nvram/read.c \
   examples/nvram/counter.c \
-  examples/nvram/policy_nv.c
+  examples/nvram/policy_nv.c \
+  examples/nvram/extend.c
 
-DISTCLEANFILES+= examples/nvram/.libs/store
-DISTCLEANFILES+= examples/nvram/.libs/read
-DISTCLEANFILES+= examples/nvram/.libs/counter
-DISTCLEANFILES+= examples/nvram/.libs/policy_nv
+DISTCLEANFILES+= examples/nvram/.libs/store \
+                 examples/nvram/.libs/read \
+                 examples/nvram/.libs/counter \
+                 examples/nvram/.libs/policy_nv \
+                 examples/nvram/.libs/extend
diff --git a/examples/nvram/nvram.h b/examples/nvram/nvram.h
index d5ab9491..97b4f297 100644
--- a/examples/nvram/nvram.h
+++ b/examples/nvram/nvram.h
@@ -32,6 +32,7 @@ int TPM2_NVRAM_Counter_Example(void* userCtx, int argc, char *argv[]);
 int TPM2_PCR_Seal_With_Policy_Auth_NV_Test(void* userCtx, int argc, char *argv[]);
 int TPM2_PCR_Seal_With_Policy_Auth_NV_External_Test(void* userCtx, int argc, char *argv[]);
 int TPM2_NVRAM_PolicyNV_Example(void* userCtx, int argc, char *argv[]);
+int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[]);
 
 #ifdef __cplusplus
     }  /* extern "C" */
diff --git a/examples/nvram/read.c b/examples/nvram/read.c
index 7dce5993..3399e4cb 100644
--- a/examples/nvram/read.c
+++ b/examples/nvram/read.c
@@ -50,12 +50,13 @@
 static void usage(void)
 {
     printf("Expected usage:\n");
-    printf("./examples/nvram/read [-nvindex] [-priv] [-pub] [-aes/-xor]\n");
+    printf("./examples/nvram/read [-nvindex] [-priv] [-pub] [-aes/-xor] [-delete]\n");
     printf("* -nvindex=[handle] (default 0x%x)\n", TPM2_DEMO_NVRAM_STORE_INDEX);
     printf("* -priv: Read ony the private part\n");
     printf("* -pub: Read only the public part\n");
     printf("* -aes/xor: Use Parameter Encryption\n");
     printf("* -endorsement/platform/owner: Auth hierarchy\n");
+    printf("* -delete: Remove NV\n");
 }
 
 int TPM2_NVRAM_Read_Example(void* userCtx, int argc, char *argv[])
@@ -77,6 +78,8 @@ int TPM2_NVRAM_Read_Example(void* userCtx, int argc, char *argv[])
     byte pubAreaBuffer[sizeof(TPM2B_PUBLIC)];
     int pubAreaSize;
     word32 nvIndex = TPM2_DEMO_NVRAM_STORE_INDEX;
+    int deleteKey = 0;
+    int nvExtend = 0;
 
     if (argc >= 2) {
         if (XSTRCMP(argv[1], "-?") == 0 ||
@@ -121,6 +124,9 @@ int TPM2_NVRAM_Read_Example(void* userCtx, int argc, char *argv[])
         else if (XSTRCMP(argv[argc-1], "-pub") == 0) {
             partialRead = PUBLIC_PART_ONLY;
         }
+        else if (XSTRCMP(argv[argc-1], "-delete") == 0) {
+            deleteKey = 1;
+        }
         else {
             printf("Warning: Unrecognized option: %s\n", argv[argc-1]);
         }
@@ -176,71 +182,91 @@ int TPM2_NVRAM_Read_Example(void* userCtx, int argc, char *argv[])
     nv.handle.auth.size = auth.size;
     XMEMCPY(nv.handle.auth.buffer, auth.buffer, auth.size);
 
-    if (partialRead != PRIVATE_PART_ONLY) {
-        readSize = sizeof(keyBlob.pub.size);
-        printf("Trying to read %d bytes of public key size marker\n", readSize);
-        rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
-            (byte*)&keyBlob.pub.size, &readSize, 0);
-        if (rc != 0) {
-            printf("Was a public key part written? (see nvram/store)\n");
-            goto exit;
-        }
-        printf("Successfully read public key part from NV\n\n");
-        offset += readSize;
-
-        readSize = sizeof(UINT16) + keyBlob.pub.size; /* account for TPM2B size marker */
-        printf("Trying to read %d bytes of public key part from NV\n", keyBlob.pub.size);
-        rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
-            pubAreaBuffer, &readSize, offset);
-        if (rc != 0) goto exit;
-        printf("Successfully read public key part from NV\n\n");
-        offset += readSize;
+    rc = wolfTPM2_NVOpen(&dev, &nv, nvIndex, NULL, 0);
+    if (rc != 0) goto exit;
 
-        /* Necessary for storing the publicArea with the correct encoding */
-        rc = TPM2_ParsePublic(&keyBlob.pub, pubAreaBuffer,
-            (word32)sizeof(pubAreaBuffer), &pubAreaSize);
-        if (rc != TPM_RC_SUCCESS) {
-            printf("Decoding of PublicArea failed. Unable to extract correctly.\n");
-            goto exit;
+    printf("NV Read: Attributes 0x%08x\n", nv.attributes);
+
+    if (((nv.attributes & TPMA_NV_TPM_NT) >> 4) & TPM_NT_EXTEND) {
+        byte digest[TPM_SHA256_DIGEST_SIZE];
+        word32 digestLen = (word32)sizeof(digest);
+        printf("NV Read Extend\n");
+        nvExtend = 1;
+        rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex, digest, &digestLen, 0);
+        if (rc == 0) {
+            printf("\tDigest: %d\n", digestLen);
+            TPM2_PrintBin(digest, digestLen);
         }
-
-#ifdef WOLFTPM_DEBUG_VERBOSE
-        TPM2_PrintPublicArea(&keyBlob.pub);
-#endif
     }
+    else {
+        if (partialRead != PRIVATE_PART_ONLY) {
+            readSize = sizeof(keyBlob.pub.size);
+            printf("Trying to read %d bytes of public key size marker\n", readSize);
+            rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
+                (byte*)&keyBlob.pub.size, &readSize, 0);
+            if (rc != 0) {
+                printf("Was a public key part written? (see nvram/store)\n");
+                goto exit;
+            }
+            printf("Successfully read public key part from NV\n\n");
+            offset += readSize;
+
+            readSize = sizeof(UINT16) + keyBlob.pub.size; /* account for TPM2B size marker */
+            printf("Trying to read %d bytes of public key part from NV\n", keyBlob.pub.size);
+            rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
+                pubAreaBuffer, &readSize, offset);
+            if (rc != 0) goto exit;
+            printf("Successfully read public key part from NV\n\n");
+            offset += readSize;
+
+            /* Necessary for storing the publicArea with the correct encoding */
+            rc = TPM2_ParsePublic(&keyBlob.pub, pubAreaBuffer,
+                (word32)sizeof(pubAreaBuffer), &pubAreaSize);
+            if (rc != TPM_RC_SUCCESS) {
+                printf("Decoding of PublicArea failed. Unable to extract correctly.\n");
+                goto exit;
+            }
 
-    if (partialRead != PUBLIC_PART_ONLY) {
-        printf("Trying to read size marker of the private key part from NV\n");
-        readSize = sizeof(keyBlob.priv.size);
-        rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
-            (byte*)&keyBlob.priv.size, &readSize, offset);
-        if (rc != 0) {
-            printf("Was a private key part written? (see nvram/store)\n");
-            goto exit;
+    #ifdef WOLFTPM_DEBUG_VERBOSE
+            TPM2_PrintPublicArea(&keyBlob.pub);
+    #endif
         }
-        printf("Successfully read size marker from NV\n\n");
-        offset += readSize;
 
-        readSize = keyBlob.priv.size;
-        printf("Trying to read %d bytes of private key part from NV\n", readSize);
-        rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
-            (byte*)&keyBlob.priv.buffer, &readSize, offset);
-        if (rc != 0) goto exit;
-        printf("Successfully read private key part from NV\n\n");
+        if (partialRead != PUBLIC_PART_ONLY) {
+            printf("Trying to read size marker of the private key part from NV\n");
+            readSize = sizeof(keyBlob.priv.size);
+            rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
+                (byte*)&keyBlob.priv.size, &readSize, offset);
+            if (rc != 0) {
+                printf("Was a private key part written? (see nvram/store)\n");
+                goto exit;
+            }
+            printf("Successfully read size marker from NV\n\n");
+            offset += readSize;
+
+            readSize = keyBlob.priv.size;
+            printf("Trying to read %d bytes of private key part from NV\n", readSize);
+            rc = wolfTPM2_NVReadAuth(&dev, &nv, nvIndex,
+                (byte*)&keyBlob.priv.buffer, &readSize, offset);
+            if (rc != 0) goto exit;
+            printf("Successfully read private key part from NV\n\n");
+        }
     }
 
     /* auth 0 is owner, no auth */
     wolfTPM2_SetAuthPassword(&dev, 0, NULL);
     wolfTPM2_UnsetAuth(&dev, 1);
 
-    parent.hndl = authHandle;
-    rc = wolfTPM2_NVDeleteAuth(&dev, &parent, nvIndex);
-    if (rc != 0) goto exit;
+    if (deleteKey) {
+        parent.hndl = authHandle;
+        rc = wolfTPM2_NVDeleteAuth(&dev, &parent, nvIndex);
+        if (rc != 0) goto exit;
+    }
 
     printf("Extraction of key from NVRAM at index 0x%x succeeded\n",
         nvIndex);
 
-    if (!partialRead) {
+    if (!nvExtend && !partialRead) {
         /* get SRK */
         rc = getPrimaryStoragekey(&dev, &storage, TPM_ALG_RSA);
         if (rc != 0) goto exit;
diff --git a/examples/nvram/store.c b/examples/nvram/store.c
index 7ef611d7..584ba453 100644
--- a/examples/nvram/store.c
+++ b/examples/nvram/store.c
@@ -51,7 +51,7 @@ static void usage(void)
 {
     printf("Expected usage:\n");
     printf("./examples/nvram/store [filename] [-nvindex] [-priv] [-pub] [-aes/-xor]\n");
-    printf("* filename: point to a file containing a TPM key\n");
+    printf("* filename: point to a file containing a TPM key (default keyblob.bin\n");
     printf("\tDefault filename is \"keyblob.bin\"\n");
     printf("* -nvindex=[handle] (default 0x%x)\n", TPM2_DEMO_NVRAM_STORE_INDEX);
     printf("* -priv: Store only the private part of the key\n");
@@ -88,9 +88,6 @@ int TPM2_NVRAM_Store_Example(void* userCtx, int argc, char *argv[])
             usage();
             return 0;
         }
-        if (argv[1][0] != '-') {
-            filename = argv[1];
-        }
     }
     while (argc > 1) {
         if (XSTRNCMP(argv[argc-1], "-nvindex=", XSTRLEN("-nvindex=")) == 0) {
@@ -124,7 +121,10 @@ int TPM2_NVRAM_Store_Example(void* userCtx, int argc, char *argv[])
         else if (XSTRCMP(argv[argc-1], "-pub") == 0) {
             partialStore = PUBLIC_PART_ONLY;
         }
-        else if (argv[argc-1][0] == '-') {
+        else if (argv[argc-1][0] != '-') {
+            filename = argv[argc-1];
+        }
+        else {
             printf("Warning: Unrecognized option: %s\n", argv[argc-1]);
         }
         argc--;
@@ -164,15 +164,15 @@ int TPM2_NVRAM_Store_Example(void* userCtx, int argc, char *argv[])
         if (rc != 0) goto exit;
     }
 
-    rc = readKeyBlob(filename, &keyBlob);
-    if (rc != 0) goto exit;
-
     /* Prepare NV_AUTHWRITE and NV_AUTHREAD attributes necessary for password */
     parent.hndl = authHandle;
     rc = wolfTPM2_GetNvAttributesTemplate(parent.hndl, &nvAttributes);
     if (rc != 0) goto exit;
 
-    /* Estimate size of NV */
+    rc = readKeyBlob(filename, &keyBlob);
+    if (rc != 0) goto exit;
+
+    /* Get maximum size of NV */
     nvSize =
         keyBlob.pub.size + sizeof(keyBlob.pub.size) + sizeof(UINT16) +
         keyBlob.priv.size + sizeof(keyBlob.priv.size) + sizeof(UINT16);
@@ -191,7 +191,7 @@ int TPM2_NVRAM_Store_Example(void* userCtx, int argc, char *argv[])
     wolfTPM2_SetAuthHandle(&dev, 0, &nv.handle);
 
     printf("Storing key at TPM NV index 0x%x with password protection\n\n",
-             nvIndex);
+            nvIndex);
 
     if (partialStore != PRIVATE_PART_ONLY) {
         printf("Public part = %hu bytes\n", keyBlob.pub.size);
@@ -205,10 +205,10 @@ int TPM2_NVRAM_Store_Example(void* userCtx, int argc, char *argv[])
         rc = TPM2_AppendPublic(pubAreaBuffer, (word32)sizeof(pubAreaBuffer),
             &pubAreaSize, &keyBlob.pub);
         /* Note:
-         * Public Area is the only part of a TPM key that can be stored encoded
-         * Private Area is stored as-is, because TPM2B_PRIVATE is byte buffer
-         * and UINT16 size field, while Public Area is a complex TCG structure.
-         */
+        * Public Area is the only part of a TPM key that can be stored encoded
+        * Private Area is stored as-is, because TPM2B_PRIVATE is byte buffer
+        * and UINT16 size field, while Public Area is a complex TCG structure.
+        */
         if (rc != TPM_RC_SUCCESS) {
             printf("Encoding of the publicArea failed. Unable to store.\n");
             goto exit;
diff --git a/examples/run_examples.sh b/examples/run_examples.sh
index 3f706a91..0612ea5b 100755
--- a/examples/run_examples.sh
+++ b/examples/run_examples.sh
@@ -38,10 +38,10 @@ RESULT=$?
 
 ./examples/keygen/create_primary -rsa -eh >> run.out 2>&1
 RESULT=$?
-[ $RESULT -ne 0 ] && echo -e "create primary endosement rsa key failed! $RESULT" && exit 1
+[ $RESULT -ne 0 ] && echo -e "create primary endorsement rsa key failed! $RESULT" && exit 1
 ./examples/keygen/create_primary -ecc -eh >> run.out 2>&1
 RESULT=$?
-[ $RESULT -ne 0 ] && echo -e "create primary endosement ecc key failed! $RESULT" && exit 1
+[ $RESULT -ne 0 ] && echo -e "create primary endorsement ecc key failed! $RESULT" && exit 1
 
 ./examples/keygen/create_primary -rsa -ph >> run.out 2>&1
 RESULT=$?
@@ -58,10 +58,10 @@ if [ $WOLFCRYPT_ENABLE -eq 1 ]; then
     # Provisioning examples (required --enable-provisioning)
     ./examples/keygen/create_primary -rsa -eh -iak -keep >> run.out 2>&1
     RESULT=$?
-    [ $RESULT -ne 0 ] && echo -e "create primary endosement rsa IAK key failed! $RESULT" && exit 1
+    [ $RESULT -ne 0 ] && echo -e "create primary endorsement rsa IAK key failed! $RESULT" && exit 1
     ./examples/keygen/create_primary -rsa -eh -idevid -keep >> run.out 2>&1
     RESULT=$?
-    [ $RESULT -ne 0 ] && echo -e "create primary endosement rsa IDevID key failed! $RESULT" && exit 1
+    [ $RESULT -ne 0 ] && echo -e "create primary endorsement rsa IDevID key failed! $RESULT" && exit 1
 
     ./examples/attestation/certify -rsa -certify=0x80000001 -signer=0x80000000 >> run.out 2>&1
     RESULT=$?
@@ -72,10 +72,10 @@ if [ $WOLFCRYPT_ENABLE -eq 1 ]; then
 
     ./examples/keygen/create_primary -ecc -eh -iak -keep >> run.out 2>&1
     RESULT=$?
-    [ $RESULT -ne 0 ] && echo -e "create primary endosement ecc IAK key failed! $RESULT" && exit 1
+    [ $RESULT -ne 0 ] && echo -e "create primary endorsement ecc IAK key failed! $RESULT" && exit 1
     ./examples/keygen/create_primary -ecc -eh -idevid -keep >> run.out 2>&1
     RESULT=$?
-    [ $RESULT -ne 0 ] && echo -e "create primary endosement ecc IDevID key failed! $RESULT" && exit 1
+    [ $RESULT -ne 0 ] && echo -e "create primary endorsement ecc IDevID key failed! $RESULT" && exit 1
 
     ./examples/attestation/certify -ecc -certify=0x80000001 -signer=0x80000000 >> run.out 2>&1
     RESULT=$?
@@ -95,10 +95,10 @@ if [ $WOLFCRYPT_ENABLE -eq 1 ]; then
 
     ./examples/keygen/create_primary -rsa -eh -aes >> run.out 2>&1
     RESULT=$?
-    [ $RESULT -ne 0 ] && echo -e "create primary endosement rsa key param enc failed! $RESULT" && exit 1
+    [ $RESULT -ne 0 ] && echo -e "create primary endorsement rsa key param enc failed! $RESULT" && exit 1
     ./examples/keygen/create_primary -ecc -eh -aes >> run.out 2>&1
     RESULT=$?
-    [ $RESULT -ne 0 ] && echo -e "create primary endosement ecc key param enc failed! $RESULT" && exit 1
+    [ $RESULT -ne 0 ] && echo -e "create primary endorsement ecc key param enc failed! $RESULT" && exit 1
 
     ./examples/keygen/create_primary -rsa -ph -aes >> run.out 2>&1
     RESULT=$?
@@ -257,8 +257,8 @@ if [ $NO_FILESYSTEM -eq 0 ]; then
     if [ $WOLFCRYPT_ENABLE -eq 1 ]; then
         ./examples/nvram/store -xor >> run.out 2>&1
         RESULT=$?
-        [ $RESULT -ne 0 ] && echo -e "nv store param enc xorfailed! $RESULT" && exit 1
-        ./examples/nvram/read -xor >> run.out 2>&1
+        [ $RESULT -ne 0 ] && echo -e "nv store param enc xor failed! $RESULT" && exit 1
+        ./examples/nvram/read -xor -delete >> run.out 2>&1
         RESULT=$?
         [ $RESULT -ne 0 ] && echo -e "nv read param enc xor failed! $RESULT" && exit 1
 
@@ -266,7 +266,7 @@ if [ $NO_FILESYSTEM -eq 0 ]; then
             ./examples/nvram/store -aes >> run.out 2>&1
             RESULT=$?
             [ $RESULT -ne 0 ] && echo -e "nv store param enc aes failed! $RESULT" && exit 1
-            ./examples/nvram/read -aes >> run.out 2>&1
+            ./examples/nvram/read -aes -delete >> run.out 2>&1
             RESULT=$?
             [ $RESULT -ne 0 ] && echo -e "nv read param enc aes failed! $RESULT" && exit 1
         fi
@@ -274,14 +274,14 @@ if [ $NO_FILESYSTEM -eq 0 ]; then
     ./examples/nvram/store -priv >> run.out 2>&1
     RESULT=$?
     [ $RESULT -ne 0 ] && echo -e "nv store priv only failed! $RESULT" && exit 1
-    ./examples/nvram/read -priv >> run.out 2>&1
+    ./examples/nvram/read -priv -delete >> run.out 2>&1
     RESULT=$?
     [ $RESULT -ne 0 ] && echo -e "nv read priv only failed! $RESULT" && exit 1
     if [ $WOLFCRYPT_ENABLE -eq 1 ]; then
         ./examples/nvram/store -priv -xor >> run.out 2>&1
         RESULT=$?
         [ $RESULT -ne 0 ] && echo -e "nv store priv only param enc xor failed! $RESULT" && exit 1
-        ./examples/nvram/read -priv -xor >> run.out 2>&1
+        ./examples/nvram/read -priv -xor -delete >> run.out 2>&1
         RESULT=$?
         [ $RESULT -ne 0 ] && echo -e "nv read priv only param enc xor failed! $RESULT" && exit 1
 
@@ -289,7 +289,7 @@ if [ $NO_FILESYSTEM -eq 0 ]; then
             ./examples/nvram/store -priv -aes >> run.out 2>&1
             RESULT=$?
             [ $RESULT -ne 0 ] && echo -e "nv store priv only param enc aes failed! $RESULT" && exit 1
-            ./examples/nvram/read -priv -aes >> run.out 2>&1
+            ./examples/nvram/read -priv -aes -delete >> run.out 2>&1
             RESULT=$?
             [ $RESULT -ne 0 ] && echo -e "nv read priv only param enc aes failed! $RESULT" && exit 1
         fi
@@ -297,9 +297,20 @@ if [ $NO_FILESYSTEM -eq 0 ]; then
     ./examples/nvram/store -pub >> run.out 2>&1
     RESULT=$?
     [ $RESULT -ne 0 ] && echo -e "nv store pub only failed! $RESULT" && exit 1
-    ./examples/nvram/read -pub >> run.out 2>&1
+    ./examples/nvram/read -pub -delete >> run.out 2>&1
     RESULT=$?
     [ $RESULT -ne 0 ] && echo -e "nv read pub only failed! $RESULT" && exit 1
+
+    if [ $WOLFCRYPT_ENABLE -eq 1 ] && [ $WOLFCRYPT_DEFAULT -eq 0 ]; then
+        # extend test
+        ./examples/nvram/extend -aes
+        RESULT=$?
+        [ $RESULT -ne 0 ] && echo -e "nv extend aes failed! $RESULT" && exit 1
+
+        ./examples/nvram/extend -xor
+        RESULT=$?
+        [ $RESULT -ne 0 ] && echo -e "nv extend xor failed! $RESULT" && exit 1
+    fi
 fi
 
 ./examples/nvram/policy_nv >> run.out 2>&1
diff --git a/examples/tpm_test.h b/examples/tpm_test.h
index 32526865..ef474789 100644
--- a/examples/tpm_test.h
+++ b/examples/tpm_test.h
@@ -44,6 +44,7 @@
 #define TPM2_DEMO_NV_TEST_INDEX         0x01800200
 #define TPM2_DEMO_NV_TEST_AUTH_INDEX    0x01800201
 #define TPM2_DEMO_NVRAM_STORE_INDEX     0x01800202
+#define TPM2_DEMO_NVRAM_EXTEND_INDEX    0x01000200
 #define TPM2_DEMO_NV_TEST_SIZE          MAX_DIGEST_BUFFER /* max size on Infineon SLB9670 is 1664 */
 #define TPM2_DEMO_NV_COUNTER_INDEX      0x01800300
 
diff --git a/src/tpm2.c b/src/tpm2.c
index 955cdfe0..9984ee70 100644
--- a/src/tpm2.c
+++ b/src/tpm2.c
@@ -5056,6 +5056,9 @@ TPM_RC TPM2_NV_Extend(NV_Extend_In* in)
         TPM2_Packet_Init(ctx, &packet);
 
         TPM2_Packet_AppendU32(&packet, in->authHandle);
+        /* When using an HMAC or Policy session make sure the NV "name" is
+         * populated in the TPM2_AUTH_SESSION name.name. This is a computed
+         * hash (see TPM2_HashNvPublic) */
         TPM2_Packet_AppendU32(&packet, in->nvIndex);
         TPM2_Packet_AppendAuth(&packet, ctx, &info);
 
diff --git a/src/tpm2_param_enc.c b/src/tpm2_param_enc.c
index 8690c1cc..dc84539a 100644
--- a/src/tpm2_param_enc.c
+++ b/src/tpm2_param_enc.c
@@ -195,11 +195,12 @@ int TPM2_KDFa(
 
 
 /* Perform XOR encryption over the first parameter of a TPM packet */
-static int TPM2_ParamEnc_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
-    TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM, BYTE *paramData,
-    UINT32 paramSz)
+static int TPM2_ParamEnc_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* sessKey,
+    TPM2B_AUTH* bindKey, TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM,
+    BYTE *paramData, UINT32 paramSz)
 {
     int rc = TPM_RC_FAILURE;
+    TPM2B_DATA keyIn;
     TPM2B_MAX_BUFFER mask;
     UINT32 i;
 
@@ -207,9 +208,17 @@ static int TPM2_ParamEnc_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
         return BUFFER_E;
     }
 
+    /* Build HMAC key input */
+    XMEMCPY(keyIn.buffer, sessKey->buffer, sessKey->size);
+    keyIn.size = sessKey->size;
+    if (bindKey != NULL) {
+        XMEMCPY(&keyIn.buffer[keyIn.size], bindKey->buffer, bindKey->size);
+        keyIn.size += bindKey->size;
+    }
+
     /* Generate XOR Mask stream matching paramater size */
     XMEMSET(mask.buffer, 0, sizeof(mask.buffer));
-    rc = TPM2_KDFa(session->authHash, (TPM2B_DATA*)keyIn, "XOR",
+    rc = TPM2_KDFa(session->authHash, &keyIn, "XOR",
         nonceCaller, nonceTPM, mask.buffer, paramSz);
     if ((UINT32)rc != paramSz) {
     #ifdef DEBUG_WOLFTPM
@@ -230,11 +239,12 @@ static int TPM2_ParamEnc_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
 }
 
 /* Perform XOR decryption over the first parameter of a TPM packet */
-static int TPM2_ParamDec_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
-    TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM, BYTE *paramData,
-    UINT32 paramSz)
+static int TPM2_ParamDec_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* sessKey,
+    TPM2B_AUTH* bindKey, TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM,
+    BYTE *paramData, UINT32 paramSz)
 {
     int rc = TPM_RC_FAILURE;
+    TPM2B_DATA keyIn;
     TPM2B_MAX_BUFFER mask;
     UINT32 i;
 
@@ -242,9 +252,17 @@ static int TPM2_ParamDec_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
         return BUFFER_E;
     }
 
+    /* Build HMAC key input */
+    XMEMCPY(keyIn.buffer, sessKey->buffer, sessKey->size);
+    keyIn.size = sessKey->size;
+    if (bindKey != NULL) {
+        XMEMCPY(&keyIn.buffer[keyIn.size], bindKey->buffer, bindKey->size);
+        keyIn.size += bindKey->size;
+    }
+
     /* Generate XOR Mask stream matching paramater size */
     XMEMSET(mask.buffer, 0, sizeof(mask.buffer));
-    rc = TPM2_KDFa(session->authHash, (TPM2B_DATA*)keyIn, "XOR",
+    rc = TPM2_KDFa(session->authHash, &keyIn, "XOR",
         nonceTPM, nonceCaller, mask.buffer, paramSz);
     if ((UINT32)rc != paramSz) {
     #ifdef DEBUG_WOLFTPM
@@ -265,11 +283,12 @@ static int TPM2_ParamDec_XOR(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
 
 #if !defined(WOLFTPM2_NO_WOLFCRYPT) && defined(WOLFSSL_AES_CFB)
 /* Perform AES CFB encryption over the first parameter of a TPM packet */
-static int TPM2_ParamEnc_AESCFB(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
-    TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM, BYTE *paramData,
-    UINT32 paramSz)
+static int TPM2_ParamEnc_AESCFB(TPM2_AUTH_SESSION *session, TPM2B_AUTH* sessKey,
+    TPM2B_AUTH* bindKey, TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM,
+    BYTE *paramData, UINT32 paramSz)
 {
     int rc = TPM_RC_FAILURE;
+    TPM2B_DATA keyIn;
     BYTE symKey[32 + 16]; /* AES key (max) + IV (block size) */
     int symKeySz = session->symmetric.keyBits.aes / 8;
     const int symKeyIvSz = 16;
@@ -279,9 +298,17 @@ static int TPM2_ParamEnc_AESCFB(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
         return BUFFER_E;
     }
 
+    /* Build HMAC key input */
+    XMEMCPY(keyIn.buffer, sessKey->buffer, sessKey->size);
+    keyIn.size = sessKey->size;
+    if (bindKey != NULL) {
+        XMEMCPY(&keyIn.buffer[keyIn.size], bindKey->buffer, bindKey->size);
+        keyIn.size += bindKey->size;
+    }
+
     /* Generate AES Key and IV */
     XMEMSET(symKey, 0, sizeof(symKey));
-    rc = TPM2_KDFa(session->authHash, (TPM2B_DATA*)keyIn, "CFB",
+    rc = TPM2_KDFa(session->authHash, &keyIn, "CFB",
         nonceCaller, nonceTPM, symKey, symKeySz + symKeyIvSz);
     if (rc != symKeySz + symKeyIvSz) {
     #ifdef DEBUG_WOLFTPM
@@ -311,11 +338,12 @@ static int TPM2_ParamEnc_AESCFB(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
 }
 
 /* Perform AES CFB decryption over the first parameter of a TPM packet */
-static int TPM2_ParamDec_AESCFB(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
-    TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM, BYTE *paramData,
-    UINT32 paramSz)
+static int TPM2_ParamDec_AESCFB(TPM2_AUTH_SESSION *session, TPM2B_AUTH* sessKey,
+    TPM2B_AUTH* bindKey, TPM2B_NONCE* nonceCaller, TPM2B_NONCE* nonceTPM,
+    BYTE *paramData, UINT32 paramSz)
 {
     int rc = TPM_RC_FAILURE;
+    TPM2B_DATA keyIn;
     BYTE symKey[32 + 16];    /* AES key 128-bit + IV (block size) */
     int symKeySz = session->symmetric.keyBits.aes / 8;
     const int symKeyIvSz = 16;
@@ -325,9 +353,17 @@ static int TPM2_ParamDec_AESCFB(TPM2_AUTH_SESSION *session, TPM2B_AUTH* keyIn,
         return BUFFER_E;
     }
 
+    /* Build HMAC key input */
+    XMEMCPY(keyIn.buffer, sessKey->buffer, sessKey->size);
+    keyIn.size = sessKey->size;
+    if (bindKey != NULL) {
+        XMEMCPY(&keyIn.buffer[keyIn.size], bindKey->buffer, bindKey->size);
+        keyIn.size += bindKey->size;
+    }
+
     /* Generate AES Key and IV */
     XMEMSET(symKey, 0, sizeof(symKey));
-    rc = TPM2_KDFa(session->authHash, (TPM2B_DATA*)keyIn, "CFB",
+    rc = TPM2_KDFa(session->authHash, &keyIn, "CFB",
         nonceTPM, nonceCaller, symKey, symKeySz + symKeyIvSz);
     if (rc != symKeySz + symKeyIvSz) {
     #ifdef DEBUG_WOLFTPM
@@ -558,6 +594,10 @@ TPM_RC TPM2_ParamEnc_CmdRequest(TPM2_AUTH_SESSION *session,
  #ifdef WOLFTPM_DEBUG_VERBOSE
     printf("CmdEnc Session Key %d\n", session->auth.size);
     TPM2_PrintBin(session->auth.buffer, session->auth.size);
+    if (session->bind != NULL) {
+        printf("CmdEnc Extra Key %d\n", session->bind->size);
+        TPM2_PrintBin(session->bind->buffer, session->bind->size);
+    }
     printf("CmdEnc Nonce caller %d\n", session->nonceCaller.size);
     TPM2_PrintBin(session->nonceCaller.buffer, session->nonceCaller.size);
     printf("CmdEnc Nonce TPM %d\n", session->nonceTPM.size);
@@ -566,14 +606,14 @@ TPM_RC TPM2_ParamEnc_CmdRequest(TPM2_AUTH_SESSION *session,
 
 
     if (session->symmetric.algorithm == TPM_ALG_XOR) {
-        rc = TPM2_ParamEnc_XOR(session, &session->auth, &session->nonceCaller,
-            &session->nonceTPM, paramData, paramSz);
+        rc = TPM2_ParamEnc_XOR(session, &session->auth, session->bind,
+            &session->nonceCaller, &session->nonceTPM, paramData, paramSz);
     }
     else if (session->symmetric.algorithm == TPM_ALG_AES &&
              session->symmetric.mode.aes == TPM_ALG_CFB) {
     #if !defined(WOLFTPM2_NO_WOLFCRYPT) && defined(WOLFSSL_AES_CFB)
-        rc = TPM2_ParamEnc_AESCFB(session, &session->auth, &session->nonceCaller,
-            &session->nonceTPM, paramData, paramSz);
+        rc = TPM2_ParamEnc_AESCFB(session, &session->auth, session->bind,
+            &session->nonceCaller, &session->nonceTPM, paramData, paramSz);
     #else
         rc = NOT_COMPILED_IN;
     #endif
@@ -590,6 +630,10 @@ TPM_RC TPM2_ParamDec_CmdResponse(TPM2_AUTH_SESSION *session,
 #ifdef WOLFTPM_DEBUG_VERBOSE
     printf("RspDec Session Key %d\n", session->auth.size);
     TPM2_PrintBin(session->auth.buffer, session->auth.size);
+    if (session->bind != NULL) {
+        printf("RspDec Extra Key %d\n", session->bind->size);
+        TPM2_PrintBin(session->bind->buffer, session->bind->size);
+    }
     printf("RspDec Nonce caller %d\n", session->nonceCaller.size);
     TPM2_PrintBin(session->nonceCaller.buffer, session->nonceCaller.size);
     printf("RspDec Nonce TPM %d\n", session->nonceTPM.size);
@@ -597,14 +641,14 @@ TPM_RC TPM2_ParamDec_CmdResponse(TPM2_AUTH_SESSION *session,
  #endif
 
     if (session->symmetric.algorithm == TPM_ALG_XOR) {
-        rc = TPM2_ParamDec_XOR(session, &session->auth, &session->nonceCaller,
-            &session->nonceTPM, paramData, paramSz);
+        rc = TPM2_ParamDec_XOR(session, &session->auth, session->bind,
+            &session->nonceCaller, &session->nonceTPM, paramData, paramSz);
     }
     else if (session->symmetric.algorithm == TPM_ALG_AES &&
              session->symmetric.mode.aes == TPM_ALG_CFB) {
     #if !defined(WOLFTPM2_NO_WOLFCRYPT) && defined(WOLFSSL_AES_CFB)
-        rc = TPM2_ParamDec_AESCFB(session, &session->auth, &session->nonceCaller,
-            &session->nonceTPM, paramData, paramSz);
+        rc = TPM2_ParamDec_AESCFB(session, &session->auth, session->bind,
+            &session->nonceCaller, &session->nonceTPM, paramData, paramSz);
     #else
         rc = NOT_COMPILED_IN;
     #endif
diff --git a/src/tpm2_wrap.c b/src/tpm2_wrap.c
index 969e1973..a0eb6dd2 100644
--- a/src/tpm2_wrap.c
+++ b/src/tpm2_wrap.c
@@ -1066,6 +1066,9 @@ int wolfTPM2_SetAuthSession(WOLFTPM2_DEV* dev, int index,
         session->policyAuth = tpmSession->handle.policyAuth;
         session->policyPass = tpmSession->handle.policyPass;
 
+        /* Capture pointer to bind */
+        session->bind = tpmSession->bind;
+
         /* define the symmetric algorithm */
         session->authHash = tpmSession->authHash;
         XMEMCPY(&session->symmetric, &tpmSession->handle.symmetric,
@@ -1536,7 +1539,6 @@ int wolfTPM2_StartSession(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* session,
     int rc;
     StartAuthSession_In  authSesIn;
     StartAuthSession_Out authSesOut;
-    TPM2B_AUTH* bindAuth = NULL;
     TPM2B_DATA keyIn;
     TPMI_ALG_HASH authHash = WOLFTPM2_WRAP_DIGEST;
     int hashDigestSz;
@@ -1556,7 +1558,8 @@ int wolfTPM2_StartSession(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* session,
     /* set session auth for key */
     if (tpmKey) {
         TPMA_SESSION sessionAttributes = 0;
-        if (encDecAlg == TPM_ALG_CFB || encDecAlg == TPM_ALG_XOR) {
+        if (bind != NULL &&
+            (encDecAlg == TPM_ALG_CFB || encDecAlg == TPM_ALG_XOR)) {
             /* if parameter encryption is enabled and key bind set, enable
              * encrypt/decrypt by default */
             sessionAttributes |= (TPMA_SESSION_decrypt | TPMA_SESSION_encrypt);
@@ -1573,7 +1576,6 @@ int wolfTPM2_StartSession(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* session,
     authSesIn.bind = (TPMI_DH_ENTITY)TPM_RH_NULL;
     if (bind) {
         authSesIn.bind = bind->hndl;
-        bindAuth = &bind->auth;
     }
 
     authSesIn.sessionType = sesType;
@@ -1632,9 +1634,10 @@ int wolfTPM2_StartSession(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* session,
     /* Calculate "key" and store into auth */
     /* key is bindAuthValue || salt */
     XMEMSET(&keyIn, 0, sizeof(keyIn));
-    if (bindAuth && bindAuth->size > 0) {
-        XMEMCPY(&keyIn.buffer[keyIn.size], bindAuth->buffer, bindAuth->size);
-        keyIn.size += bindAuth->size;
+    if (bind && bind->auth.size > 0) {
+        XMEMCPY(&keyIn.buffer[keyIn.size], bind->auth.buffer,
+            bind->auth.size);
+        keyIn.size += bind->auth.size;
     }
     if (session->salt.size > 0) {
         XMEMCPY(&keyIn.buffer[keyIn.size], session->salt.buffer,
@@ -1667,6 +1670,7 @@ int wolfTPM2_StartSession(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* session,
     session->handle.hndl = authSesOut.sessionHandle;
     wolfTPM2_CopySymmetric(&session->handle.symmetric, &authSesIn.symmetric);
     if (bind) {
+        session->bind = &bind->auth; /* pointer to bind key auth */
         wolfTPM2_CopyName(&session->handle.name, &bind->name);
     }
     session->nonceCaller.size = authSesIn.nonceCaller.size;
@@ -4498,13 +4502,16 @@ int wolfTPM2_NVCreate(WOLFTPM2_DEV* dev, TPM_HANDLE authHandle,
         maxSize, auth, authSz);
 }
 
-int wolfTPM2_NVWriteAuthPolicy(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* tpmSession,
+static int wolfTPM2_NVWriteData(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* tpmSession,
     TPM_ALG_ID pcrAlg, byte* pcrArray, word32 pcrArraySz, WOLFTPM2_NV* nv,
-    word32 nvIndex, byte* dataBuf, word32 dataSz, word32 offset)
+    word32 nvIndex, byte* dataBuf, word32 dataSz, word32 offset, int extend)
 {
     int rc = TPM_RC_SUCCESS;
     word32 pos = 0, towrite;
-    NV_Write_In in;
+    union {
+        NV_Write_In write;
+        NV_Extend_In extend;
+    } in;
 
     if (dev == NULL || nv == NULL || dataBuf == NULL) {
         return BAD_FUNC_ARG;
@@ -4541,29 +4548,34 @@ int wolfTPM2_NVWriteAuthPolicy(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* tpmSession,
         rc |= wolfTPM2_SetAuthHandleName(dev, 1, &nv->handle);
         if (rc != TPM_RC_SUCCESS) {
         #ifdef DEBUG_WOLFTPM
-            printf("Setting NV index name failed\n");
+            printf("wolfTPM2_NVWriteData: Setting NV index name failed\n");
         #endif
             rc = TPM_RC_FAILURE;
             break;
         }
 
         XMEMSET(&in, 0, sizeof(in));
-        in.authHandle = nv->handle.hndl;
-        in.nvIndex = nvIndex;
-        in.offset = offset+pos;
-        in.data.size = towrite;
+        in.write.authHandle = nv->handle.hndl;
+        in.write.nvIndex = nvIndex;
+        in.write.data.size = towrite;
         if (dataBuf)
-            XMEMCPY(in.data.buffer, &dataBuf[pos], towrite);
-
-        rc = TPM2_NV_Write(&in);
+            XMEMCPY(in.write.data.buffer, &dataBuf[pos], towrite);
+        if (!extend) {
+            in.write.offset = offset+pos;
+            rc = TPM2_NV_Write(&in.write);
+        }
+        else {
+            rc = TPM2_NV_Extend(&in.extend);
+        }
         if (rc != TPM_RC_SUCCESS) {
             break;
         }
 
     #ifdef DEBUG_WOLFTPM
-        printf("TPM2_NV_Write: Auth 0x%x, Idx 0x%x, Offset %d, Size %d\n",
-            (word32)in.authHandle, (word32)in.nvIndex,
-            in.offset, in.data.size);
+        printf("wolfTPM2_NVWriteData: Auth 0x%x, Idx 0x%x, Offset %d, Size %d, "
+            "Extend %d\n",
+            (word32)in.write.authHandle, (word32)in.write.nvIndex,
+            in.write.offset, in.write.data.size, extend);
     #endif
 
         pos += towrite;
@@ -4572,18 +4584,34 @@ int wolfTPM2_NVWriteAuthPolicy(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* tpmSession,
 
 #ifdef DEBUG_WOLFTPM
     if (rc != TPM_RC_SUCCESS) {
-        printf("TPM2_NV_Write failed %d: %s\n", rc, wolfTPM2_GetRCString(rc));
+        printf("wolfTPM2_NVWriteData failed %d: %s\n",
+            rc, wolfTPM2_GetRCString(rc));
     }
 #endif
 
     return rc;
 }
 
+int wolfTPM2_NVExtend(WOLFTPM2_DEV* dev, WOLFTPM2_NV* nv,
+    word32 nvIndex, byte* dataBuf, word32 dataSz)
+{
+    return wolfTPM2_NVWriteData(dev, NULL, TPM_ALG_NULL, NULL, 0,
+        nv, nvIndex, dataBuf, dataSz, 0, 1);
+}
+
+int wolfTPM2_NVWriteAuthPolicy(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* tpmSession,
+    TPM_ALG_ID pcrAlg, byte* pcrArray, word32 pcrArraySz, WOLFTPM2_NV* nv,
+    word32 nvIndex, byte* dataBuf, word32 dataSz, word32 offset)
+{
+    return wolfTPM2_NVWriteData(dev, tpmSession, pcrAlg, pcrArray, pcrArraySz,
+        nv, nvIndex, dataBuf, dataSz, offset, 0);
+}
+
 int wolfTPM2_NVWriteAuth(WOLFTPM2_DEV* dev, WOLFTPM2_NV* nv,
     word32 nvIndex, byte* dataBuf, word32 dataSz, word32 offset)
 {
-    return wolfTPM2_NVWriteAuthPolicy(dev, NULL, TPM_ALG_NULL, NULL, 0,
-        nv, nvIndex, dataBuf, dataSz, offset);
+    return wolfTPM2_NVWriteData(dev, NULL, TPM_ALG_NULL, NULL, 0,
+        nv, nvIndex, dataBuf, dataSz, offset, 0);
 }
 
 /* older API kept for compatibility, recommend using wolfTPM2_NVWriteAuth */
@@ -4789,6 +4817,7 @@ int wolfTPM2_NVOpen(WOLFTPM2_DEV* dev, WOLFTPM2_NV* nv, word32 nvIndex,
 
     /* flag that the NV was "opened" and name was loaded */
     nv->handle.nameLoaded = 1;
+    nv->attributes = nvPublic.attributes;
 
     return rc;
 }
diff --git a/wolftpm/tpm2.h b/wolftpm/tpm2.h
index d72e8c44..38e8f358 100644
--- a/wolftpm/tpm2.h
+++ b/wolftpm/tpm2.h
@@ -1552,7 +1552,7 @@ typedef UINT32 TPMA_NV;
 #define TPMA_NV_OWNERWRITE     0x00000002UL
 #define TPMA_NV_AUTHWRITE      0x00000004UL
 #define TPMA_NV_POLICYWRITE    0x00000008UL
-#define TPMA_NV_TPM_NT         0x000000F0UL
+#define TPMA_NV_TPM_NT         0x000000F0UL /* index type see TPM_NT_ */
 #define TPMA_NV_POLICY_DELETE  0x00000400UL
 #define TPMA_NV_WRITELOCKED    0x00000800UL
 #define TPMA_NV_WRITEALL       0x00001000UL
@@ -1654,6 +1654,7 @@ typedef struct TPM2_AUTH_SESSION {
     TPMI_ALG_HASH authHash;
     TPM2B_NAME name;
     TPM2B_AUTH auth;
+    TPM2B_AUTH* bind;
 
     unsigned int policyAuth : 1; /* if policy auth should be used */
     unsigned int policyPass : 1;
diff --git a/wolftpm/tpm2_wrap.h b/wolftpm/tpm2_wrap.h
index 4932b58f..8fc26d74 100644
--- a/wolftpm/tpm2_wrap.h
+++ b/wolftpm/tpm2_wrap.h
@@ -51,6 +51,7 @@ typedef struct WOLFTPM2_SESSION {
     TPM2B_DIGEST    salt;         /* User defined */
     TPMI_ALG_HASH   authHash;
     TPMA_SESSION    sessionAttributes;
+    TPM2B_AUTH*     bind;         /* pointer to bind auth password */
 } WOLFTPM2_SESSION;
 
 typedef struct WOLFTPM2_DEV {
@@ -92,6 +93,7 @@ typedef struct WOLFTPM2_HASH {
 
 typedef struct WOLFTPM2_NV {
     WOLFTPM2_HANDLE handle;
+    TPMA_NV attributes;
 } WOLFTPM2_NV;
 
 typedef struct WOLFTPM2_HMAC {
@@ -2014,6 +2016,29 @@ WOLFTPM_API int wolfTPM2_NVWriteAuthPolicy(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION*
     TPM_ALG_ID pcrAlg, byte* pcrArray, word32 pcrArraySz, WOLFTPM2_NV* nv,
     word32 nvIndex, byte* dataBuf, word32 dataSz, word32 offset);
 
+/*!
+    \ingroup wolfTPM2_Wrappers
+    \brief Extend data to an NV index
+    \note When NV index is read it will return the digest
+
+    \return TPM_RC_SUCCESS: successful
+    \return TPM_RC_FAILURE: generic failure (check TPM IO and TPM return code)
+    \return BAD_FUNC_ARG: check the provided arguments
+
+    \param dev pointer to a TPM2_DEV struct
+    \param nv pointer to a populated structure of WOLFTPM2_NV type
+    \param nvIndex integer value, holding an existing NV Index Handle value
+    \param dataBuf pointer to a byte buffer, containing the user data to be written to the TPM's NVRAM
+    \param dataSz integer value, specifying the size of the user data buffer, in bytes
+
+    \sa wolfTPM2_NVReadAuth
+    \sa wolfTPM2_NVCreateAuth
+    \sa wolfTPM2_NVOpen
+    \sa wolfTPM2_NVDeleteAuth
+*/
+WOLFTPM_API int wolfTPM2_NVExtend(WOLFTPM2_DEV* dev, WOLFTPM2_NV* nv,
+    word32 nvIndex, byte* dataBuf, word32 dataSz);
+
 /*!
     \ingroup wolfTPM2_Wrappers
     \brief Reads user data from a NV Index, starting at the given offset

From 671b702786cba4f89adce41e5705fd4ec7dd5171 Mon Sep 17 00:00:00 2001
From: David Garske <david@wolfssl.com>
Date: Mon, 16 Dec 2024 14:17:15 -0800
Subject: [PATCH 2/3] Allow extend with RSA or ECC.

---
 examples/nvram/extend.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/examples/nvram/extend.c b/examples/nvram/extend.c
index 1b147b42..2cbc4bbc 100644
--- a/examples/nvram/extend.c
+++ b/examples/nvram/extend.c
@@ -173,8 +173,14 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
         goto exit;
     }
 
-    /* 1: Create EK RSA 2048-bit */
-    rc = wolfTPM2_CreateEK(&dev, &endorse, TPM_ALG_RSA);
+    /* 1: Create EK (RSA or ECC) */
+    rc = wolfTPM2_CreateEK(&dev, &endorse,
+    #ifndef NO_RSA
+        TPM_ALG_RSA
+    #else
+        TPM_ALG_ECC
+    #endif
+    );
     if (rc != 0) {
         printf("Create EK RSA failed!\n");
         goto exit;

From 15add23dcfed4e587939f7f35ab6d90afa3bec4c Mon Sep 17 00:00:00 2001
From: David Garske <david@wolfssl.com>
Date: Tue, 17 Dec 2024 11:13:10 -0800
Subject: [PATCH 3/3] Add code for calculating NV extend policies. Fixed issue
 with `wolfTPM2_PolicyHash` where input digest could be too large.

---
 examples/nvram/extend.c | 123 +++++++++++++++++++++++-----------------
 src/tpm2_wrap.c         |   3 +
 2 files changed, 73 insertions(+), 53 deletions(-)

diff --git a/examples/nvram/extend.c b/examples/nvram/extend.c
index 2cbc4bbc..a0adb8da 100644
--- a/examples/nvram/extend.c
+++ b/examples/nvram/extend.c
@@ -27,15 +27,17 @@
 #endif
 
 #include <wolftpm/tpm2_wrap.h>
+#include <wolftpm/tpm2_packet.h>
 #include <stdio.h>
 
-#ifndef WOLFTPM2_NO_WRAPPER
+#if !defined(WOLFTPM2_NO_WRAPPER) && !defined(WOLFTPM2_NO_WOLFCRYPT)
 
 #include <examples/nvram/nvram.h>
 #include <hal/tpm_io.h>
 #include <examples/tpm_test.h>
 #include <examples/tpm_test_keys.h>
 
+
 /******************************************************************************/
 /* --- BEGIN TPM NVRAM Extend Example -- */
 /******************************************************************************/
@@ -48,50 +50,26 @@ static void usage(void)
     printf("* -aes/xor: Use Parameter Encryption\n");;
 }
 
-/* Policy A: TPM2_PolicyCommandCode -> TPM_CC_NV_Read */
-static const byte policyA[] = {
-    0x47, 0xCE, 0x30, 0x32, 0xD8, 0xBA, 0xD1, 0xF3,
-    0x08, 0x9C, 0xB0, 0xC0, 0x90, 0x88, 0xDE, 0x43,
-    0x50, 0x14, 0x91, 0xD4, 0x60, 0x40, 0x2B, 0x90,
-    0xCD, 0x1B, 0x7F, 0xC0, 0xB6, 0x8C, 0xA9, 0x2F
-};
-/* Policy B: TPM2_PolicyCommandCode -> TPM_CC_NV_Extend */
-static const byte policyB[] = {
-    0xB6, 0xA2, 0xE7, 0x14, 0x2E, 0xE5, 0x6F, 0xD9,
-    0x78, 0x04, 0x74, 0x88, 0x48, 0x3D, 0xAA, 0x5B,
-    0x42, 0xB8, 0xDC, 0x4C, 0xC7, 0xDD, 0xCC, 0xED,
-    0xDF, 0xB9, 0x17, 0x93, 0xCF, 0x1F, 0xF1, 0xB7
-};
-/* Policy C: TPM2_PolicyCommandCode -> TPM_CC_PolicyNV */
-static const byte policyC[] = {
-    0x20, 0x3E, 0x4B, 0xD5, 0xD0, 0x44, 0x8C, 0x96,
-    0x15, 0xCC, 0x13, 0xFA, 0x18, 0xE8, 0xD3, 0x92,
-    0x22, 0x44, 0x1C, 0xC4, 0x02, 0x04, 0xD9, 0x9A,
-    0x77, 0x26, 0x20, 0x68, 0xDB, 0xD5, 0x5A, 0x43
-};
-
-/* pre-computed policy:
- * NV Read (A), NV Extend (B), PolicyNV (C), then policy OR (A/B/C) */
-static const byte policyNv[] = {
-    0x7F, 0x17, 0x93, 0x7E, 0x20, 0x62, 0x79, 0xA3,
-    0xF7, 0x55, 0xFB, 0x60, 0xF4, 0x0C, 0xF1, 0x26,
-    0xB7, 0x0E, 0x5B, 0x1D, 0x9B, 0xF2, 0x02, 0x86,
-    0x6D, 0x52, 0x76, 0x13, 0x87, 0x4A, 0x64, 0xAC
-};
-
-
-static int PolicyOrApply(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* policySession)
+static int BuildPolicyCommandCode(TPMI_ALG_HASH hashAlg,
+    byte* digest, word32* digestSz, TPM_CC cc)
+{
+    word32 val = cpu_to_be32(cc);
+    return wolfTPM2_PolicyHash(hashAlg, digest, digestSz,
+        TPM_CC_PolicyCommandCode, (byte*)&val, sizeof(val));
+}
+
+static int PolicyOrApply(WOLFTPM2_DEV* dev, WOLFTPM2_SESSION* policySession,
+    byte** hashList, word32 hashListSz, word32 digestSz)
 {
+    word32 i;
     PolicyOR_In policyOR;
     XMEMSET(&policyOR, 0, sizeof(policyOR));
     policyOR.policySession = policySession->handle.hndl;
-    policyOR.pHashList.count = 3;
-    policyOR.pHashList.digests[0].size = sizeof(policyA);
-    XMEMCPY(policyOR.pHashList.digests[0].buffer, policyA, sizeof(policyA));
-    policyOR.pHashList.digests[1].size = sizeof(policyB);
-    XMEMCPY(policyOR.pHashList.digests[1].buffer, policyB, sizeof(policyB));
-    policyOR.pHashList.digests[2].size = sizeof(policyC);
-    XMEMCPY(policyOR.pHashList.digests[2].buffer, policyC, sizeof(policyC));
+    policyOR.pHashList.count = hashListSz;
+    for (i=0; i<hashListSz; i++) {
+        policyOR.pHashList.digests[i].size = digestSz;
+        XMEMCPY(policyOR.pHashList.digests[i].buffer, hashList[i], digestSz);
+    }
     (void)dev;
     return TPM2_PolicyOR(&policyOR);
 }
@@ -109,11 +87,15 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
     int paramEncAlg = TPM_ALG_CFB;
     TPMI_RH_NV_AUTH authHandle = TPM_RH_PLATFORM;
     word32 nvIndex = TPM2_DEMO_NVRAM_EXTEND_INDEX;
-    word32 nvSize; /* 32 for SHA2-256 */
     byte*  auth = (byte*)"cpusecret";
     word32 authSz = (word32)XSTRLEN((const char*)auth);
-    byte   nvDigest[32];
-    word32 nvDigestSz = (word32)sizeof(nvDigest);
+    TPMI_ALG_HASH hashAlg = WOLFTPM2_WRAP_DIGEST;
+    word32 nvSize = TPM2_GetHashDigestSize(hashAlg);
+    byte   nvDigest[TPM_MAX_DIGEST_SIZE]; /* buffer for nv read */
+    byte   policyDigest[3*TPM_MAX_DIGEST_SIZE]; /* Policy A/B/C */
+    word32 policyDigestSz = 0;
+    byte*  policy[3]; /* pointers to policy A/B/C */
+    byte   policyOr[TPM_MAX_DIGEST_SIZE];
 
     if (argc >= 2) {
         if (XSTRCMP(argv[1], "-?") == 0 ||
@@ -166,6 +148,8 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
     XMEMSET(&bind, 0, sizeof(bind));
     XMEMSET(&nv, 0, sizeof(nv));
     XMEMSET(&nvAuth, 0, sizeof(nvAuth));
+    XMEMSET(nvDigest, 0, sizeof(nvDigest));
+    XMEMSET(policyDigest, 0, sizeof(policyDigest));
 
     rc = wolfTPM2_Init(&dev, TPM2_IoCb, userCtx);
     if (rc != TPM_RC_SUCCESS) {
@@ -173,6 +157,39 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
         goto exit;
     }
 
+    /* Build Policies A/B/C */
+    /* Policy A: TPM2_PolicyCommandCode -> TPM_CC_NV_Read */
+    /* 47ce3032d8bad1f3089cb0c09088de43501491d460402b90cd1b7fc0b68ca92f */
+    policy[0] = &policyDigest[policyDigestSz];
+    BuildPolicyCommandCode(hashAlg, policy[0], &nvSize, TPM_CC_NV_Read);
+    printf("PolicyA: %d\n", nvSize);
+    TPM2_PrintBin(policy[0], nvSize);
+    policyDigestSz += nvSize;
+
+    /* Policy B: TPM2_PolicyCommandCode -> TPM_CC_NV_Extend */
+    /* b6a2e7142ee56fd978047488483daa5b42b8dc4cc7ddcceddfb91793cf1ff1b7 */
+    policy[1] = &policyDigest[policyDigestSz];
+    BuildPolicyCommandCode(hashAlg, policy[1], &nvSize, TPM_CC_NV_Extend);
+    printf("PolicyB: %d\n", nvSize);
+    TPM2_PrintBin(policy[1], nvSize);
+    policyDigestSz += nvSize;
+
+    /* Policy C: TPM2_PolicyCommandCode -> TPM_CC_PolicyNV */
+    /* 203e4bd5d0448c9615cc13fa18e8d39222441cc40204d99a77262068dbd55a43 */
+    policy[2] = &policyDigest[policyDigestSz];
+    BuildPolicyCommandCode(hashAlg, policy[2], &nvSize, TPM_CC_PolicyNV);
+    printf("PolicyC: %d\n", nvSize);
+    TPM2_PrintBin(policy[2], nvSize);
+    policyDigestSz += nvSize;
+
+    /* Policy OR A/B/C */
+    /* 7f17937e206279a3f755fb60f40cf126b70e5b1d9bf202866d527613874a64ac */
+    XMEMSET(policyOr, 0, sizeof(policyOr));
+    rc = wolfTPM2_PolicyHash(hashAlg, policyOr, &nvSize,
+        TPM_CC_PolicyOR, policyDigest, policyDigestSz);
+    printf("PolicyOR A/B/C: %d\n", nvSize);
+    TPM2_PrintBin(policyOr, nvSize);
+
     /* 1: Create EK (RSA or ECC) */
     rc = wolfTPM2_CreateEK(&dev, &endorse,
     #ifndef NO_RSA
@@ -227,7 +244,7 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
             nvAttributes, /* needs TPM_NT_EXTEND set */
             nvSize, /* must match nameAlg digest size */
             auth, authSz, /* the password to bind session with */
-            policyNv, (word32)sizeof(policyNv)
+            policyOr, nvSize
         );
     }
 
@@ -255,7 +272,7 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
     /* 5. Satisfy policy for NV Extend (policy B) */
     rc = wolfTPM2_PolicyCommandCode(&dev, &tpmSession, TPM_CC_NV_Extend);
     if (rc == 0) {
-        rc = PolicyOrApply(&dev, &tpmSession);
+        rc = PolicyOrApply(&dev, &tpmSession, policy, 3, nvSize);
     }
     if (rc != 0) {
         printf("Failed to apply policy B\n");
@@ -280,7 +297,7 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
     /* 8. Satisfy policy for NV Read (policy A) */
     rc = wolfTPM2_PolicyCommandCode(&dev, &tpmSession, TPM_CC_NV_Read);
     if (rc == 0) {
-        rc = PolicyOrApply(&dev, &tpmSession);
+        rc = PolicyOrApply(&dev, &tpmSession, policy, 3, nvSize);
     }
     if (rc != 0) {
         printf("Failed to apply policy A\n");
@@ -289,10 +306,10 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
 
     /* 9. Read NV extend digest */
     rc = wolfTPM2_NVRead(&dev, authHandle, nv.handle.hndl,
-        nvDigest, &nvDigestSz, 0);
+        nvDigest, &nvSize, 0);
     if (rc == 0) {
-        printf("NV Digest: %d\n", nvDigestSz);
-        TPM2_PrintBin(nvDigest, nvDigestSz);
+        printf("NV Digest: %d\n", nvSize);
+        TPM2_PrintBin(nvDigest, nvSize);
 
         /* Should be:
          * 0ad80f8e4450587760d9137df41c9374f657bafa621fe37d4d5c8cecf0bcce5e */
@@ -313,17 +330,17 @@ int TPM2_NVRAM_Extend_Example(void* userCtx, int argc, char *argv[])
 /******************************************************************************/
 /* --- END TPM NVRAM Extend Example -- */
 /******************************************************************************/
-#endif /* !WOLFTPM2_NO_WRAPPER */
+#endif /* !WOLFTPM2_NO_WRAPPER && !WOLFTPM2_NO_WOLFCRYPT */
 
 #ifndef NO_MAIN_DRIVER
 int main(int argc, char *argv[])
 {
     int rc = NOT_COMPILED_IN;
 
-#ifndef WOLFTPM2_NO_WRAPPER
+#if !defined(WOLFTPM2_NO_WRAPPER) && !defined(WOLFTPM2_NO_WOLFCRYPT)
     rc = TPM2_NVRAM_Extend_Example(NULL, argc, argv);
 #else
-    printf("NVRAM code not compiled in\n");
+    printf("NVRAM extend code not compiled in\n");
     (void)argc;
     (void)argv;
 #endif
diff --git a/src/tpm2_wrap.c b/src/tpm2_wrap.c
index a0eb6dd2..0aa7564b 100644
--- a/src/tpm2_wrap.c
+++ b/src/tpm2_wrap.c
@@ -7499,6 +7499,9 @@ int wolfTPM2_PolicyHash(TPM_ALG_ID hashAlg,
 
     /* policyDigestOld */
     if (rc == 0 && inSz > 0) {
+        /* old digest cannot be larger than digest size */
+        if (inSz > *digestSz)
+            inSz = *digestSz;
         rc = wc_HashUpdate(&hash_ctx, hashType, digest, inSz);
     }
     /* Command Code (optional) */