char* secure_dev_tpm_get_storage_key(SEC_DEVICE_HANDLE handle)
{
char* result;
if (handle == NULL)
{
/* Codes_SRS_SECURE_DEVICE_TPM_07_016: [ If handle is NULL, secure_dev_tpm_get_storage_key shall return NULL. ] */
LogError("Invalid handle value specified");
result = NULL;
}
else if (handle->srk_pub.publicArea.unique.rsa.t.size == 0)
{
/* Codes_SRS_SECURE_DEVICE_TPM_07_017: [ If the srk_public value was not initialized, secure_dev_tpm_get_storage_key shall return NULL. ] */
LogError("storage root key is invalid");
result = NULL;
}
else
{
unsigned char data_bytes[1024];
unsigned char* data_pos = data_bytes;
/* Codes_SRS_SECURE_DEVICE_TPM_07_018: [ secure_dev_tpm_get_storage_key shall allocate and return the Storage Root Key. ] */
uint32_t data_length = TPM2B_PUBLIC_Marshal(&handle->srk_pub, &data_pos, NULL);
STRING_HANDLE encoded_srk = Azure_Base64_Encode_Bytes(data_bytes, data_length);
if (encoded_srk == NULL)
{
/* Codes_SRS_SECURE_DEVICE_TPM_07_019: [ If any failure is encountered, secure_dev_tpm_get_storage_key shall return NULL. ] */
LogError("Failure encoding storage root key");
result = NULL;
}
else
{
if (mallocAndStrcpy_s(&result, STRING_c_str(encoded_srk)) != 0)
{
/* Codes_SRS_SECURE_DEVICE_TPM_07_019: [ If any failure is encountered, secure_dev_tpm_get_storage_key shall return NULL. ] */
LogError("Failure allocating storage root key");
result = NULL;
}
STRING_delete(encoded_srk);
}
}
return result;
}
static uint32_t
TpmUtilSignAppPayload(
ANY_OBJECT* appPayloadAuthority
)
{
DEFINE_CALL_BUFFERS;
UINT32 result = TPM_RC_SUCCESS;
union
{
Hash_In hash;
Sign_In sign;
VerifySignature_In verifySignature;
} in;
union
{
Hash_Out hash;
Sign_Out sign;
VerifySignature_Out verifySignature;
} out;
TPM2B_DIGEST digest = {0};
TPMT_TK_HASHCHECK hashCheck = {0};
TPMT_SIGNATURE signature = {0};
const UINT64 marker = TPM_APP_AUTHORITY_SECTION;
uint8_t appPayload[] = {
0x54, 0x68, 0x65, 0x20, 0x71, 0x75, 0x69, 0x63, 0x6b, 0x20, 0x62, 0x72, 0x6f, 0x77, 0x6e, 0x20, // The quick brown
0x66, 0x6f, 0x78, 0x20, 0x6a, 0x75, 0x6d, 0x70, 0x73, 0x20, 0x6f, 0x76, 0x65, 0x72, 0x20, 0x74, // fox jumps over t
0x68, 0x65, 0x20, 0x6c, 0x61, 0x7a, 0x79, 0x20, 0x64, 0x6f, 0x67 // he lazy dog
};
// Hash the payload in the TPM
INITIALIZE_CALL_BUFFERS(TPM2_Hash, &in.hash, &out.hash);
in.hash.data.t.size = sizeof(appPayload);
MemoryCopy(in.hash.data.t.buffer, appPayload, in.hash.data.t.size, sizeof(in.hash.data.t.buffer));
#ifdef NTZTPM
in.hash.hashAlg = TPM_ALG_SM3_256;
#else
in.hash.hashAlg = TPM_ALG_SHA256;
#endif
in.hash.hierarchy = TPM_RH_NULL;
EXECUTE_TPM_CALL(FALSE, TPM2_Hash);
digest = out.hash.outHash;
hashCheck = out.hash.validation;
// Sign the digest
INITIALIZE_CALL_BUFFERS(TPM2_Sign, &in.sign, &out.sign);
parms.objectTableIn[TPM2_Sign_HdlIn_KeyHandle] = *appPayloadAuthority;
in.sign.digest = digest;
in.sign.inScheme.scheme = TPM_ALG_NULL;
in.sign.validation = hashCheck;
EXECUTE_TPM_CALL(FALSE, TPM2_Sign);
signature = out.sign.signature;
// Verify the signature
INITIALIZE_CALL_BUFFERS(TPM2_VerifySignature, &in.verifySignature, &out.verifySignature);
parms.objectTableIn[TPM2_VerifySignature_HdlIn_KeyHandle] = *appPayloadAuthority;
in.verifySignature.digest = digest;
in.verifySignature.signature = signature;
EXECUTE_TPM_CALL(FALSE, TPM2_VerifySignature);
// Dump the appPayload data
if(sizeof(pbCmd) < (sizeof(appPayload) + sizeof(UINT64)))
{
result = TPM_RC_FAILURE;
goto Cleanup;
}
MemorySet(pbCmd, 0x00, sizeof(pbCmd));
buffer = pbCmd;
size = sizeof(pbCmd);
MemoryCopy(pbCmd, appPayload, sizeof(appPayload), size);
buffer += sizeof(appPayload);
size -= sizeof(appPayload);
MemoryCopy(buffer, &marker, sizeof(TPM_APP_AUTHORITY_SECTION), size);
buffer += sizeof(UINT64);
size -= sizeof(UINT64);
if((TPM2B_PUBLIC_Marshal(&appPayloadAuthority->obj.publicArea, &buffer, &size) < 0) ||
(TPMT_SIGNATURE_Marshal(&signature, &buffer, &size) < 0))
{
result = TPM_RC_FAILURE;
goto Cleanup;
}
// Write the fakeAppPayload to flash
HAL_FLASH_Program(FLASH_TYPEPROGRAM_WORD, ADDR_FLASH_SECTOR_23 + sizeof(persistedData), (uint32_t)(sizeof(pbCmd) - size));
for(uint32_t n = 0; n < (sizeof(pbCmd) - size); n++)
{
if(HAL_FLASH_Program(FLASH_TYPEPROGRAM_BYTE, ADDR_FLASH_SECTOR_23 + sizeof(persistedData) + sizeof(uint32_t) + n, pbCmd[n]) != HAL_OK)
{
printf("Flash Write Error @ 0x%08x\r\n", ADDR_FLASH_SECTOR_23 + n);
}
}
Cleanup:
return result;
}
