Decryptor/Decryptor/Decryptor.cpp

/*
 * Copyright (C) 2011-2017 Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */


// Enclave2.cpp : Defines the exported functions for the DLL application
#include "sgx_eid.h"
#include "sgx_tcrypto.h"
#include "Decryptor_t.h"
#include "EnclaveMessageExchange.h"
#include "error_codes.h"
#include "Utility_Decryptor.h"
#include "sgx_thread.h"
#include "sgx_dh.h"
#include <map>
#include "sgx_tcrypto.h"
#include "LocalAttestationCode_t.h"
#include "sgx_tseal.h"

// internal-internal
uint32_t create_ecdsa_key_pair(sgx_ec256_public_t* pub_key, sgx_ec256_private_t* priv_key);
void serialize_key_pair_to_string( sgx_ec256_public_t* pub_key, sgx_ec256_private_t* signing_priv_key, uint8_t* private_public_key_string);
void deserialize_string_to_key_pair(uint8_t* private_public_key_string, sgx_ec256_public_t* pub_key, sgx_ec256_private_t* priv_key); 
uint32_t create_and_sign_mitigator_header_value();

uint32_t calculate_sealed_data_size( uint32_t input_size) ; 
uint32_t create_and_seal_ecdsa_signing_key_pair(__attribute__((unused))   sgx_ec256_public_t* pub_key, __attribute__((unused))  uint32_t* sealed_data_length,  __attribute__((unused)) uint8_t* sealed_data); 
uint32_t unseal_and_restore_sealed_signing_key_pair(__attribute__((unused)) sgx_ec256_public_t* pub_key, uint8_t* sealed_data, size_t* sgx_sealed_data_length);
//uint32_t create_and_sign_mitigator_header_value(); 
uint32_t decrypt_verifiers_message_set_apache_mrsigner(uint8_t* ciphertext, uint8_t* tag);
uint32_t encrypt_mitigator_header_to_apache(uint8_t* ciphertext, uint8_t* tag);


uint32_t one_la_done=0; 
sgx_ec256_public_t short_term_pub_key;
sgx_ec256_private_t short_term_priv_key; 
sgx_ec256_signature_t generated_signature;
sgx_measurement_t apache_mr_signer; 
sgx_measurement_t verifier_mr_enclave;
sgx_ec256_private_t signing_priv_key;

extern "C" uint32_t verify_peer_enclave_trust(__attribute__((unused))  sgx_dh_session_enclave_identity_t* peer_enclave_identity)
{
	uint32_t count;
	if(!peer_enclave_identity)
	{
		return INVALID_PARAMETER_ERROR;
	}
	if(one_la_done==0)
	{
                for(count=0; count<SGX_HASH_SIZE; count++)
			verifier_mr_enclave.m[count]=peer_enclave_identity->mr_enclave.m[count]; 
		memset(&(apache_mr_signer.m),0x0,SGX_HASH_SIZE); // "initialization" 
		one_la_done=1;

	}
	else // apache enclave
	{
		sgx_measurement_t actual_mr_signer = peer_enclave_identity->mr_signer;
		// verifier's mrsigner 
		//    uint8_t expected_mr_signer[32] ={0xdf, 0xd7, 0x3b, 0x93, 0xea, 0x39, 0x02, 0x02, 0x3c, 0xd0, 0x52, 0x1a, 0xbd, 0x00, 0xaf, 0xb9, 0xa6, 0x54, 0x57, 0x3e, 0xe5, 0xef, 0x36, 0xf4, 0x8c, 0xc2, 0x4d, 0x92, 0x70, 0xae, 0xd4, 0x7c}; 
		int count;
		for(count=0; count<SGX_HASH_SIZE; count++)
		{
			if( actual_mr_signer.m[count] != apache_mr_signer.m[count] )
				return ENCLAVE_TRUST_ERROR; 
		}
	}
	return SGX_SUCCESS;
}

// This needs to be called after the first local attestation is successful - otherwise, the internal apache_mr_signer.m will not be set properly for the comparison of the mrsigner for the 2nd LA in verify_peer_enclave_trust. 
// (I.e. if it is not called then DoS 
uint32_t decrypt_verifiers_message_set_apache_mrsigner(uint8_t* ciphertext, uint8_t* tag)
{
return 	decrypt(ciphertext, 32, tag, (uint8_t*) &(apache_mr_signer.m)); 
//	if(mrsigner_decryption_successful !=0)
//		return mrsigner_decryption_successful; 
}

// ciphertext assumed to be at least 64 bytes, tag - at least 16 bytes
uint32_t encrypt_mitigator_header_to_apache(uint8_t* ciphertext, uint8_t* tag)
{
	uint32_t ret_status=create_and_sign_mitigator_header_value();
	if(ret_status != SGX_SUCCESS)
        {
		//      printf("Could not generate or sign another keypair for client-side, error:%x.\n", ret_status); fflush(stdout);
		return 0xFFFFFFDD;
	}

	// serializing the weird signature string
	uint8_t mitigator_header_unencrypted[64]; 
	uint8_t *current_sig_byte = (uint8_t*)(&(generated_signature.x)); 
	uint32_t ecdsa_sig_count; 
	for(ecdsa_sig_count=0;ecdsa_sig_count<32;ecdsa_sig_count++)
		mitigator_header_unencrypted[ecdsa_sig_count]=*(current_sig_byte+ecdsa_sig_count); 
        current_sig_byte = (uint8_t*)(&(generated_signature.y)); 
        for(ecdsa_sig_count=0;ecdsa_sig_count<32;ecdsa_sig_count++)
                mitigator_header_unencrypted[ecdsa_sig_count+32]=*(current_sig_byte+ecdsa_sig_count); 

	ret_status = encrypt_internal(mitigator_header_unencrypted, 64, tag, ciphertext); 
	return ret_status; 
}




uint32_t create_ecdsa_key_pair(sgx_ec256_public_t* pub_key, sgx_ec256_private_t* priv_key)
{
  sgx_status_t se_ret; sgx_status_t se_ret2;
  //create ECC context
  sgx_ecc_state_handle_t ecc_state = NULL;
  se_ret = sgx_ecc256_open_context(&ecc_state);
  if(SGX_SUCCESS != se_ret)
    return se_ret;

  // generate private key and public key
  se_ret = sgx_ecc256_create_key_pair(priv_key, pub_key, ecc_state);
  se_ret2 = sgx_ecc256_close_context(ecc_state);

  if(SGX_SUCCESS != se_ret || se_ret2!= SGX_SUCCESS) // something weird has happened - couldn't shut it down.
    return 0xFFFFFFFF;
  return SGX_SUCCESS;
}

// todo: set to private
// todo: assumes that the length of the keystring is at least 3*SGX_ECP256_KEY_SIZE
void serialize_key_pair_to_string(sgx_ec256_public_t* pub_key, sgx_ec256_private_t* signing_priv_key, uint8_t* private_public_key_string)
{
  if(private_public_key_string != NULL)  // nowhere to serialize to
  {
     uint32_t counter;
     if(pub_key != NULL)  // public key to serialize
     {
        for(counter=0;counter<SGX_ECP256_KEY_SIZE; counter++)
          *(private_public_key_string+counter)=pub_key->gx[counter];

        for(counter=SGX_ECP256_KEY_SIZE;counter<2*SGX_ECP256_KEY_SIZE; counter++)
           *(private_public_key_string+counter)=pub_key->gy[counter-SGX_ECP256_KEY_SIZE];
     }

     if(signing_priv_key != NULL) // private key to serialize
     {
       for(counter=2*SGX_ECP256_KEY_SIZE;counter<3*SGX_ECP256_KEY_SIZE; counter++)
          *(private_public_key_string+counter)=signing_priv_key->r[counter - 2*SGX_ECP256_KEY_SIZE];
     } 
  }
}


// todo: set to private
void deserialize_string_to_key_pair(uint8_t* private_public_key_string, sgx_ec256_public_t* pub_key, sgx_ec256_private_t* signing_priv_key)
{
  if(private_public_key_string != NULL) // nowhere to deserialize from 
  {
    uint32_t counter;
    if(signing_priv_key != NULL) 
    {

     for(counter=2*SGX_ECP256_KEY_SIZE;counter<3*SGX_ECP256_KEY_SIZE; counter++)
       signing_priv_key->r[counter-2*SGX_ECP256_KEY_SIZE]=*(private_public_key_string+counter);
    }

    if(pub_key != NULL)
    {
      for(counter=0;counter<SGX_ECP256_KEY_SIZE; counter++)
        	pub_key->gx[counter]=*(private_public_key_string+counter);

      for(counter=SGX_ECP256_KEY_SIZE;counter<2*SGX_ECP256_KEY_SIZE; counter++)
  	pub_key->gy[counter-SGX_ECP256_KEY_SIZE]=*(private_public_key_string+counter);
    }
  }
}


uint32_t create_and_seal_ecdsa_signing_key_pair(__attribute__((unused))   sgx_ec256_public_t* pub_key, __attribute__((unused))  uint32_t* sealed_data_length,
 __attribute__((unused)) uint8_t* sealed_data)
{
    uint32_t ret_status; sgx_ec256_private_t private_key;  uint32_t counter;
    ret_status=create_ecdsa_key_pair(pub_key, &private_key);
    if(ret_status!=SGX_SUCCESS)
       return ret_status;
    for(counter=0;counter<SGX_ECP256_KEY_SIZE; counter++)
	signing_priv_key.r[counter]=private_key.r[counter]; 
    // generating the entire string as there is no SGX function to generate the public key from the private one.
    uint8_t* private_public_key_string = (uint8_t*) malloc(3*SGX_ECP256_KEY_SIZE);
    uint8_t* sealed_data2 = (uint8_t*) malloc(*sealed_data_length);
    // serializing keypair to string
    serialize_key_pair_to_string(pub_key, &private_key, private_public_key_string);
    uint8_t* private_key_string = (uint8_t*) malloc(SGX_ECP256_KEY_SIZE); 
    for(counter=0;counter<SGX_ECP256_KEY_SIZE;counter++)
	*(private_key_string+counter)=private_key.r[counter];
//    return *sealed_data_length;
    ret_status = sgx_seal_data(0, NULL, 3*SGX_ECP256_KEY_SIZE, private_public_key_string, *sealed_data_length, (sgx_sealed_data_t*) sealed_data2); 
    for(counter=0;counter<*sealed_data_length;counter++)
	*(sealed_data+counter)=*(sealed_data2+counter); 
    free(sealed_data2);
    free(private_key_string);  //free(private_key);  
    free(private_public_key_string);

    return ret_status; // SGX_SUCCESS; 
}

/*
uint32_t unseal_and_restore_sealed_signing_key_pair(__attribute__((unused)) sgx_ec256_public_t* pub_key, __attribute__((unused))  uint8_t* sealed_data, __attribute__((unused))   uint32_t* sgx_sealed_data_length)
{
	return SGX_SUCCESS; 

}*/

uint32_t unseal_and_restore_sealed_signing_key_pair(__attribute__((unused)) sgx_ec256_public_t* pub_key, uint8_t* sealed_data, size_t* sgx_sealed_data_length)
{
  uint32_t expected_plaintext_msg_length; uint8_t* temp_plaintext; uint32_t counter; uint32_t ret_status;
  expected_plaintext_msg_length = sgx_get_encrypt_txt_len((sgx_sealed_data_t*)sealed_data);
  if(expected_plaintext_msg_length == 0xffffffff)
    return 0xFFFFFFFF;

//  uint32_t return_status; 
  uint8_t* sealed_data2 = (uint8_t*) malloc(*sgx_sealed_data_length); 
  for(counter=0;counter<*sgx_sealed_data_length;counter++)
  {
	*(sealed_data2+counter)=*(sealed_data+counter); 
  }

  temp_plaintext = (uint8_t*)malloc( expected_plaintext_msg_length );
  ret_status = sgx_unseal_data((sgx_sealed_data_t*)sealed_data2, NULL, 0, temp_plaintext, &expected_plaintext_msg_length);
  if(ret_status != SGX_SUCCESS)
  {
    free(temp_plaintext);free(sealed_data2);
    switch(ret_status)
    {
      case SGX_ERROR_MAC_MISMATCH:
          // MAC of the sealed data is incorrect.          The sealed data has been tampered.
          break;
      case SGX_ERROR_INVALID_ATTRIBUTE:
          // Indicates attribute field of the sealed data is incorrect.
          break;
      case SGX_ERROR_INVALID_ISVSVN:
          // Indicates isv_svn field of the sealed data is greater than            the enclave�s ISVSVN. This is a downgraded enclave.
          break;
      case SGX_ERROR_INVALID_CPUSVN:
          // Indicates cpu_svn field of the sealed data is greater than            the platform�s cpu_svn. enclave is  on a downgraded platform.
          break;
      case SGX_ERROR_INVALID_KEYNAME:
          // Indicates key_name field of the sealed data is incorrect.
          break;
      default:
          // other errors
          break;
    }
    return ret_status;
  }
   
  deserialize_string_to_key_pair(temp_plaintext, pub_key, &signing_priv_key);
  free(temp_plaintext); free(sealed_data2);  
  return SGX_SUCCESS;
}

uint32_t create_and_sign_mitigator_header_value()
{
	// Otherwise: DoS or possible bypass (fake verifier does LA  but real verifier mrenclave is given out by decryptor) - signature with junk verifier mrenclave  or whatever is in the memory. 
	if(one_la_done < 1)
		return 0xde;  //  This needs to be called at any point after the first local attestation is done - else, a junk verifier mrenclave will be included in the signature
	// TODO: Comment this
	memset(&(verifier_mr_enclave.m), 0x01, 32); 

	// create key pair
	uint32_t ret_status = create_ecdsa_key_pair(&short_term_pub_key, &short_term_priv_key);  uint32_t counter;
	uint32_t ret_status2;
        if(ret_status!=SGX_SUCCESS)
           return ret_status;
	// serialize public key, append mr_enclave 
	uint8_t* public_key_string = (uint8_t*) malloc(3*SGX_ECP256_KEY_SIZE); // for .edl file - size parameter for serialize is 96 and this fits coz we need to append the mr_enclave to the pub key 
	serialize_key_pair_to_string(&short_term_pub_key, NULL, public_key_string);
	for(counter=32*2; counter<32*3; counter++) // appending mr_enclave
		*(public_key_string+counter)=verifier_mr_enclave.m[counter]; 
	// retrieve long-term private key from global variable - apparently, need to create a local copy or it crashes
	sgx_ec256_private_t long_term_priv_key;
	for(counter=0; counter<SGX_ECP256_KEY_SIZE; counter++) 
		long_term_priv_key.r[counter] = signing_priv_key.r[counter];  
	// sign public key with long-term private key 
	sgx_ec256_signature_t local_signature; sgx_ecc_state_handle_t ecc_handle; 
	//// opening context for signature
	ret_status = sgx_ecc256_open_context(&ecc_handle); 
	if(ret_status != SGX_SUCCESS) 
		return ret_status; 
	ret_status = sgx_ecdsa_sign(public_key_string,2*SGX_ECP256_KEY_SIZE, &long_term_priv_key, &local_signature, ecc_handle);
	ret_status2 = sgx_ecc256_close_context(ecc_handle); 
	free(public_key_string); 
	if(ret_status == SGX_SUCCESS) 
	{
		for(counter=0;counter<SGX_NISTP_ECP256_KEY_SIZE/sizeof(uint32_t); counter++)
		{
			generated_signature.x[counter] = local_signature.x[counter]; 
                        generated_signature.y[counter] = local_signature.y[counter]; 
		}
	}
	if(ret_status != SGX_SUCCESS || ret_status2 != SGX_SUCCESS)
		return 0xFFFFFFFF;
	return 0; 
}


uint32_t calculate_sealed_data_size( uint32_t input_size) 
{
//      *op_size=sgx_calc_sealed_data_size(0, input_size); 
        return sgx_calc_sealed_data_size(0, input_size);

}