app-ethereum/src_plugins/eth2/eth2_plugin.c

#ifdef HAVE_ETH2

#include <string.h>
#include "eth_plugin_internal.h"
#include "eth_plugin_handler.h"
#include "shared_context.h"
#include "ethUtils.h"
#include "utils.h"

void getEth2PublicKey(uint32_t *bip32Path, uint8_t bip32PathLength, uint8_t *out);

#define WITHDRAWAL_KEY_PATH_1 12381
#define WITHDRAWAL_KEY_PATH_2 3600
#define WITHDRAWAL_KEY_PATH_3 0

#define ETH2_DEPOSIT_PUBKEY_OFFSET 0x80
#define ETH2_WITHDRAWAL_CREDENTIALS_OFFSET 0xE0
#define ETH2_SIGNATURE_OFFSET 0x120
#define ETH2_DEPOSIT_PUBKEY_LENGTH 0x30
#define ETH2_WITHDRAWAL_CREDENTIALS_LENGTH 0x20
#define ETH2_SIGNATURE_LENGTH 0x60

typedef struct eth2_deposit_parameters_t {
	uint8_t valid;
} eth2_deposit_parameters_t;

void eth2_plugin_call(int message, void *parameters) {

	switch(message) {
		case ETH_PLUGIN_INIT_CONTRACT: {
			ethPluginInitContract_t *msg = (ethPluginInitContract_t*)parameters;
			eth2_deposit_parameters_t *context = (eth2_deposit_parameters_t*)msg->pluginContext;
			context->valid = 1;
			msg->result = ETH_PLUGIN_RESULT_OK;
		}
			break;

		case ETH_PLUGIN_PROVIDE_PARAMETER : {
			ethPluginProvideParameter_t *msg = (ethPluginProvideParameter_t*)parameters;
			eth2_deposit_parameters_t *context = (eth2_deposit_parameters_t*)msg->pluginContext;
			uint32_t index;
			PRINTF("eth2 plugin provide parameter %d %.*H\n", msg->parameterOffset, 32, msg->parameter);
			switch(msg->parameterOffset) {
				case 4 + (32 * 0): // pubkey offset					
				case 4 + (32 * 1):  // withdrawal credentials offset
				case 4 + (32 * 2): // signature offset
				case 4 + (32 * 4): // deposit pubkey length
				case 4 + (32 * 7): // withdrawal credentials length
				case 4 + (32 * 9): // signature length 
				{
					uint32_t check = 0;
					switch(msg->parameterOffset) {
						case 4 + (32 * 0):
							check = ETH2_DEPOSIT_PUBKEY_OFFSET;
							break;
						case 4 + (32 * 1):
							check = ETH2_WITHDRAWAL_CREDENTIALS_OFFSET;
							break;
						case 4 + (32 * 2):
							check = ETH2_SIGNATURE_OFFSET;
							break;
						case 4 + (32 * 4):
							check = ETH2_DEPOSIT_PUBKEY_LENGTH;
							break;
						case 4 + (32 * 7):
							check = ETH2_WITHDRAWAL_CREDENTIALS_LENGTH;
							break;
						case 4 + (32 * 9):
							check = ETH2_SIGNATURE_LENGTH;
							break;
						default:
							break;
					}
					index = U4BE(msg->parameter,  32 - 4);
					if (index != check) {
						PRINTF("eth2 plugin parameter check %d failed, expected %d got %d\n", msg->parameterOffset, check, index);
						context->valid = 0;
					}
					msg->result = ETH_PLUGIN_RESULT_OK;
				}
					break;

				case 4 + (32 * 3): // deposit data root
				case 4 + (32 * 5): // deposit pubkey
				case 4 + (32 * 6):
				case 4 + (32 * 10): // signature
				case 4 + (32 * 11):
				case 4 + (32 * 12):
					msg->result = ETH_PLUGIN_RESULT_OK;
					break;

				case 4 + (32 * 8): // withdrawal credentials
				{
					 uint8_t tmp[48];
					 uint32_t withdrawalKeyPath[4];
					 withdrawalKeyPath[0] = WITHDRAWAL_KEY_PATH_1;
					 withdrawalKeyPath[1] = WITHDRAWAL_KEY_PATH_2;
					 withdrawalKeyPath[2] = WITHDRAWAL_KEY_PATH_3;
					 withdrawalKeyPath[3] = eth2WithdrawalIndex;
					 getEth2PublicKey(withdrawalKeyPath, 4, tmp);
					 PRINTF("eth2 plugin computed withdrawal public key %.*H\n", 48, tmp);
					 cx_hash_sha256(tmp, 48, tmp, 32);
					 tmp[0] = 0;
					 if (memcmp(tmp, msg->parameter, 32) != 0) {
					 	PRINTF("eth2 plugin invalid withdrawal credentials\n");
					 	PRINTF("Got %.*H\n", 32, msg->parameter);
					 	PRINTF("Expected %.*H\n", 32, tmp);
					 	context->valid = 0;
					 }
					 msg->result = ETH_PLUGIN_RESULT_OK;
				}
					break;

				default:
					PRINTF("Unhandled parameter offset\n");
					break;
			}
		}
		break;

		case ETH_PLUGIN_FINALIZE: {
			ethPluginFinalize_t *msg = (ethPluginFinalize_t*)parameters;
			eth2_deposit_parameters_t *context = (eth2_deposit_parameters_t*)msg->pluginContext;
			PRINTF("eth2 plugin finalize\n");
			if (context->valid) {
				msg->numScreens = 1;
				msg->uiType = ETH_UI_TYPE_GENERIC;
				msg->result = ETH_PLUGIN_RESULT_OK;
			}
			else {
				msg->result = ETH_PLUGIN_RESULT_FALLBACK;
			}
		}
		break;

		case ETH_PLUGIN_QUERY_CONTRACT_ID: {
			ethQueryContractID_t *msg = (ethQueryContractID_t*)parameters;
			strcpy(msg->name, "ETH2");
			strcpy(msg->version, "Deposit");
			msg->result = ETH_PLUGIN_RESULT_OK;
		}
		break;

		case ETH_PLUGIN_QUERY_CONTRACT_UI: {
			ethQueryContractUI_t *msg = (ethQueryContractUI_t*)parameters;
			//eth2_deposit_parameters_t *context = (eth2_deposit_parameters_t*)msg->pluginContext;
			switch(msg->screenIndex) {
				case 0: {
				  uint8_t decimals = WEI_TO_ETHER;
  				uint8_t *ticker = (uint8_t *)PIC(chainConfig->coinName);
					strcpy(msg->title, "Amount");
					amountToString(tmpContent.txContent.value.value, tmpContent.txContent.value.length, decimals, (char*)ticker, msg->msg, 100);
					msg->result = ETH_PLUGIN_RESULT_OK;
				}
					break;
				default:
					break;
			}
		}
		break;

		default:
			PRINTF("Unhandled message %d\n", message);			
	}
}

#endif