app-ethereum/src_features/performPrivacyOperation/cmd_performPrivacyOperation.c

#include "shared_context.h"
#include "apdu_constants.h"

#include "feature_performPrivacyOperation.h"
#include "common_ui.h"
#include "uint_common.h"

#define P2_PUBLIC_ENCRYPTION_KEY 0x00
#define P2_SHARED_SECRET         0x01

void decodeScalar(const uint8_t *scalarIn, uint8_t *scalarOut) {
    for (uint8_t i = 0; i < 32; i++) {
        switch (i) {
            case 0:
                scalarOut[0] = (scalarIn[31] & 0x7f) | 0x40;
                break;
            case 31:
                scalarOut[31] = scalarIn[0] & 0xf8;
                break;
            default:
                scalarOut[i] = scalarIn[31 - i];
        }
    }
}

void handlePerformPrivacyOperation(uint8_t p1,
                                   uint8_t p2,
                                   const uint8_t *dataBuffer,
                                   uint8_t dataLength,
                                   unsigned int *flags,
                                   unsigned int *tx) {
    uint8_t privateKeyData[64];
    uint8_t privateKeyDataSwapped[INT256_LENGTH];
    bip32_path_t bip32;
    cx_err_t status = CX_OK;

    if ((p1 != P1_CONFIRM) && (p1 != P1_NON_CONFIRM)) {
        THROW(0x6B00);
    }

    if ((p2 != P2_PUBLIC_ENCRYPTION_KEY) && (p2 != P2_SHARED_SECRET)) {
        THROW(0x6700);
    }

    dataBuffer = parseBip32(dataBuffer, &dataLength, &bip32);

    if (dataBuffer == NULL) {
        THROW(0x6a80);
    }

    if ((p2 == P2_SHARED_SECRET) && (dataLength < 32)) {
        THROW(0x6700);
    }

    cx_ecfp_private_key_t privateKey;

    CX_ASSERT(os_derive_bip32_no_throw(
        CX_CURVE_256K1,
        bip32.path,
        bip32.length,
        privateKeyData,
        (tmpCtx.publicKeyContext.getChaincode ? tmpCtx.publicKeyContext.chainCode : NULL)));
    CX_ASSERT(cx_ecfp_init_private_key_no_throw(CX_CURVE_256K1, privateKeyData, 32, &privateKey));
    CX_ASSERT(cx_ecfp_generate_pair_no_throw(CX_CURVE_256K1,
                                             &tmpCtx.publicKeyContext.publicKey,
                                             &privateKey,
                                             1));
    getEthAddressStringFromRawKey((const uint8_t *) &tmpCtx.publicKeyContext.publicKey.W,
                                  tmpCtx.publicKeyContext.address,
                                  chainConfig->chainId);
    if (p2 == P2_PUBLIC_ENCRYPTION_KEY) {
        decodeScalar(privateKeyData, privateKeyDataSwapped);
        CX_ASSERT(cx_ecfp_init_private_key_no_throw(CX_CURVE_Curve25519,
                                                    privateKeyDataSwapped,
                                                    32,
                                                    &privateKey));
        CX_ASSERT(cx_ecfp_generate_pair_no_throw(CX_CURVE_Curve25519,
                                                 &tmpCtx.publicKeyContext.publicKey,
                                                 &privateKey,
                                                 1));
        explicit_bzero(privateKeyDataSwapped, sizeof(privateKeyDataSwapped));
    } else {
        memmove(tmpCtx.publicKeyContext.publicKey.W + 1, dataBuffer, 32);
        status = cx_x25519(tmpCtx.publicKeyContext.publicKey.W + 1, privateKeyData, 32);
    }
    explicit_bzero(&privateKey, sizeof(privateKey));
    explicit_bzero(privateKeyData, sizeof(privateKeyData));

    if (status != CX_OK) {
        THROW(0x6A80);
    }

    if (p1 == P1_NON_CONFIRM) {
        *tx = set_result_perform_privacy_operation();
        THROW(0x9000);
    } else {
        snprintf(strings.common.toAddress,
                 sizeof(strings.common.toAddress),
                 "0x%.*s",
                 40,
                 tmpCtx.publicKeyContext.address);
        for (uint8_t i = 0; i < 32; i++) {
            privateKeyData[i] = tmpCtx.publicKeyContext.publicKey.W[32 - i];
        }
        format_hex(privateKeyData,
                   32,
                   strings.common.fullAmount,
                   sizeof(strings.common.fullAmount) - 1);

        if (p2 == P2_PUBLIC_ENCRYPTION_KEY) {
            ui_display_privacy_public_key();
        } else {
            ui_display_privacy_shared_secret();
        }

        *flags |= IO_ASYNCH_REPLY;
    }
}