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trezor-mcu/firmware/ethereum.c

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/*
* This file is part of the TREZOR project, https://trezor.io/
*
* Copyright (C) 2016 Alex Beregszaszi <alex@rtfs.hu>
* Copyright (C) 2016 Pavol Rusnak <stick@satoshilabs.com>
* Copyright (C) 2016 Jochen Hoenicke <hoenicke@gmail.com>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "ethereum.h"
#include "fsm.h"
#include "layout2.h"
#include "messages.h"
#include "transaction.h"
#include "ecdsa.h"
#include "protect.h"
#include "crypto.h"
#include "secp256k1.h"
#include "sha3.h"
#include "address.h"
#include "util.h"
#include "gettext.h"
#include "ethereum_tokens.h"
/* maximum supported chain id. v must fit in an uint32_t. */
#define MAX_CHAIN_ID 2147483630
static bool ethereum_signing = false;
static uint32_t data_total, data_left;
static EthereumTxRequest msg_tx_request;
static CONFIDENTIAL uint8_t privkey[32];
static uint32_t chain_id;
struct SHA3_CTX keccak_ctx;
static inline void hash_data(const uint8_t *buf, size_t size)
{
sha3_Update(&keccak_ctx, buf, size);
}
/*
* Push an RLP encoded length to the hash buffer.
*/
static void hash_rlp_length(uint32_t length, uint8_t firstbyte)
{
uint8_t buf[4];
if (length == 1 && firstbyte <= 0x7f) {
/* empty length header */
} else if (length <= 55) {
buf[0] = 0x80 + length;
hash_data(buf, 1);
} else if (length <= 0xff) {
buf[0] = 0xb7 + 1;
buf[1] = length;
hash_data(buf, 2);
} else if (length <= 0xffff) {
buf[0] = 0xb7 + 2;
buf[1] = length >> 8;
buf[2] = length & 0xff;
hash_data(buf, 3);
} else {
buf[0] = 0xb7 + 3;
buf[1] = length >> 16;
buf[2] = length >> 8;
buf[3] = length & 0xff;
hash_data(buf, 4);
}
}
/*
* Push an RLP encoded list length to the hash buffer.
*/
static void hash_rlp_list_length(uint32_t length)
{
uint8_t buf[4];
if (length <= 55) {
buf[0] = 0xc0 + length;
hash_data(buf, 1);
} else if (length <= 0xff) {
buf[0] = 0xf7 + 1;
buf[1] = length;
hash_data(buf, 2);
} else if (length <= 0xffff) {
buf[0] = 0xf7 + 2;
buf[1] = length >> 8;
buf[2] = length & 0xff;
hash_data(buf, 3);
} else {
buf[0] = 0xf7 + 3;
buf[1] = length >> 16;
buf[2] = length >> 8;
buf[3] = length & 0xff;
hash_data(buf, 4);
}
}
/*
* Push an RLP encoded length field and data to the hash buffer.
*/
static void hash_rlp_field(const uint8_t *buf, size_t size)
{
hash_rlp_length(size, buf[0]);
hash_data(buf, size);
}
/*
* Push an RLP encoded number to the hash buffer.
* Ethereum yellow paper says to convert to big endian and strip leading zeros.
*/
static void hash_rlp_number(uint32_t number)
{
if (!number) {
return;
}
uint8_t data[4];
data[0] = (number >> 24) & 0xff;
data[1] = (number >> 16) & 0xff;
data[2] = (number >> 8) & 0xff;
data[3] = (number) & 0xff;
int offset = 0;
while (!data[offset]) {
offset++;
}
hash_rlp_field(data + offset, 4 - offset);
}
/*
* Calculate the number of bytes needed for an RLP length header.
* NOTE: supports up to 16MB of data (how unlikely...)
* FIXME: improve
*/
static int rlp_calculate_length(int length, uint8_t firstbyte)
{
if (length == 1 && firstbyte <= 0x7f) {
return 1;
} else if (length <= 55) {
return 1 + length;
} else if (length <= 0xff) {
return 2 + length;
} else if (length <= 0xffff) {
return 3 + length;
} else {
return 4 + length;
}
}
static void send_request_chunk(void)
{
int progress = 1000 - (data_total > 1000000
? data_left / (data_total/800)
: data_left * 800 / data_total);
layoutProgress(_("Signing"), progress);
msg_tx_request.has_data_length = true;
msg_tx_request.data_length = data_left <= 1024 ? data_left : 1024;
msg_write(MessageType_MessageType_EthereumTxRequest, &msg_tx_request);
}
static int ethereum_is_canonic(uint8_t v, uint8_t signature[64])
{
(void) signature;
return (v & 2) == 0;
}
static void send_signature(void)
{
uint8_t hash[32], sig[64];
uint8_t v;
layoutProgress(_("Signing"), 1000);
/* eip-155 replay protection */
if (chain_id != 0) {
/* hash v=chain_id, r=0, s=0 */
hash_rlp_number(chain_id);
hash_rlp_length(0, 0);
hash_rlp_length(0, 0);
}
keccak_Final(&keccak_ctx, hash);
if (ecdsa_sign_digest(&secp256k1, privkey, hash, sig, &v, ethereum_is_canonic) != 0) {
fsm_sendFailure(FailureType_Failure_ProcessError, _("Signing failed"));
ethereum_signing_abort();
return;
}
memset(privkey, 0, sizeof(privkey));
/* Send back the result */
msg_tx_request.has_data_length = false;
msg_tx_request.has_signature_v = true;
if (chain_id) {
msg_tx_request.signature_v = v + 2 * chain_id + 35;
} else {
msg_tx_request.signature_v = v + 27;
}
msg_tx_request.has_signature_r = true;
msg_tx_request.signature_r.size = 32;
memcpy(msg_tx_request.signature_r.bytes, sig, 32);
msg_tx_request.has_signature_s = true;
msg_tx_request.signature_s.size = 32;
memcpy(msg_tx_request.signature_s.bytes, sig + 32, 32);
msg_write(MessageType_MessageType_EthereumTxRequest, &msg_tx_request);
ethereum_signing_abort();
}
/* Format a 256 bit number (amount in wei) into a human readable format
* using standard ethereum units.
* The buffer must be at least 25 bytes.
*/
static void ethereumFormatAmount(const bignum256 *amnt, const TokenType *token, char *buf, int buflen)
{
bignum256 bn1e9;
bn_read_uint32(1000000000, &bn1e9);
const char *suffix = NULL;
int decimals = 18;
if (token == UnknownToken) {
strlcpy(buf, "Unknown token value", buflen);
return;
} else
if (token != NULL) {
suffix = token->ticker;
decimals = token->decimals;
} else
if (bn_is_less(amnt, &bn1e9)) {
suffix = " Wei";
decimals = 0;
} else {
switch (chain_id) {
case 1: suffix = " ETH"; break; // Ethereum Mainnet
case 61: suffix = " ETC"; break; // Ethereum Classic Mainnet
case 62: suffix = " tETC"; break; // Ethereum Classic Testnet
case 30: suffix = " RSK"; break; // Rootstock Mainnet
case 31: suffix = " tRSK"; break; // Rootstock Testnet
case 3: suffix = " tETH"; break; // Ethereum Testnet: Ropsten
case 4: suffix = " tETH"; break; // Ethereum Testnet: Rinkeby
case 42: suffix = " tETH"; break; // Ethereum Testnet: Kovan
case 2: suffix = " EXP"; break; // Expanse
case 8: suffix = " UBQ"; break; // UBIQ
default: suffix = " UNKN"; break; // unknown chain
}
}
bn_format(amnt, NULL, suffix, decimals, 0, false, buf, buflen);
}
static void layoutEthereumConfirmTx(const uint8_t *to, uint32_t to_len, const uint8_t *value, uint32_t value_len, const TokenType *token)
{
bignum256 val;
uint8_t pad_val[32];
memset(pad_val, 0, sizeof(pad_val));
memcpy(pad_val + (32 - value_len), value, value_len);
bn_read_be(pad_val, &val);
char amount[32];
if (token == NULL) {
if (bn_is_zero(&val)) {
strcpy(amount, _("message"));
} else {
ethereumFormatAmount(&val, NULL, amount, sizeof(amount));
}
} else {
ethereumFormatAmount(&val, token, amount, sizeof(amount));
}
char _to1[] = "to 0x__________";
char _to2[] = "_______________";
char _to3[] = "_______________?";
if (to_len) {
char to_str[41];
ethereum_address_checksum(to, to_str);
memcpy(_to1 + 5, to_str, 10);
memcpy(_to2, to_str + 10, 15);
memcpy(_to3, to_str + 25, 15);
} else {
strlcpy(_to1, _("to new contract?"), sizeof(_to1));
strlcpy(_to2, "", sizeof(_to2));
strlcpy(_to3, "", sizeof(_to3));
}
layoutDialogSwipe(&bmp_icon_question,
_("Cancel"),
_("Confirm"),
NULL,
_("Send"),
amount,
_to1,
_to2,
_to3,
NULL
);
}
static void layoutEthereumData(const uint8_t *data, uint32_t len, uint32_t total_len)
{
char hexdata[3][17];
char summary[20];
uint32_t printed = 0;
for (int i = 0; i < 3; i++) {
uint32_t linelen = len - printed;
if (linelen > 8) {
linelen = 8;
}
data2hex(data, linelen, hexdata[i]);
data += linelen;
printed += linelen;
}
strcpy(summary, "... bytes");
char *p = summary + 11;
uint32_t number = total_len;
while (number > 0) {
*p-- = '0' + number % 10;
number = number / 10;
}
char *summarystart = summary;
if (total_len == printed)
summarystart = summary + 4;
layoutDialogSwipe(&bmp_icon_question,
_("Cancel"),
_("Confirm"),
NULL,
_("Transaction data:"),
hexdata[0],
hexdata[1],
hexdata[2],
summarystart,
NULL
);
}
static void layoutEthereumFee(const uint8_t *value, uint32_t value_len,
const uint8_t *gas_price, uint32_t gas_price_len,
const uint8_t *gas_limit, uint32_t gas_limit_len,
bool is_token)
{
bignum256 val, gas;
uint8_t pad_val[32];
char tx_value[32];
char gas_value[32];
memset(pad_val, 0, sizeof(pad_val));
memcpy(pad_val + (32 - gas_price_len), gas_price, gas_price_len);
bn_read_be(pad_val, &val);
memset(pad_val, 0, sizeof(pad_val));
memcpy(pad_val + (32 - gas_limit_len), gas_limit, gas_limit_len);
bn_read_be(pad_val, &gas);
bn_multiply(&val, &gas, &secp256k1.prime);
ethereumFormatAmount(&gas, NULL, gas_value, sizeof(gas_value));
memset(pad_val, 0, sizeof(pad_val));
memcpy(pad_val + (32 - value_len), value, value_len);
bn_read_be(pad_val, &val);
if (bn_is_zero(&val)) {
strcpy(tx_value, is_token ? _("token") : _("message"));
} else {
ethereumFormatAmount(&val, NULL, tx_value, sizeof(tx_value));
}
layoutDialogSwipe(&bmp_icon_question,
_("Cancel"),
_("Confirm"),
NULL,
_("Really send"),
tx_value,
_("paying up to"),
gas_value,
_("for gas?"),
NULL
);
}
/*
* RLP fields:
* - nonce (0 .. 32)
* - gas_price (0 .. 32)
* - gas_limit (0 .. 32)
* - to (0, 20)
* - value (0 .. 32)
* - data (0 ..)
*/
static bool ethereum_signing_check(EthereumSignTx *msg)
{
if (!msg->has_gas_price || !msg->has_gas_limit) {
return false;
}
if (msg->to.size != 20 && msg->to.size != 0) {
/* Address has wrong length */
return false;
}
// sending transaction to address 0 (contract creation) without a data field
if (msg->to.size == 0 && (!msg->has_data_length || msg->data_length == 0)) {
return false;
}
if (msg->gas_price.size + msg->gas_limit.size > 30) {
// sanity check that fee doesn't overflow
return false;
}
return true;
}
void ethereum_signing_init(EthereumSignTx *msg, const HDNode *node)
{
ethereum_signing = true;
sha3_256_Init(&keccak_ctx);
memset(&msg_tx_request, 0, sizeof(EthereumTxRequest));
/* set fields to 0, to avoid conditions later */
if (!msg->has_value)
msg->value.size = 0;
if (!msg->has_data_initial_chunk)
msg->data_initial_chunk.size = 0;
if (!msg->has_to)
msg->to.size = 0;
if (!msg->has_nonce)
msg->nonce.size = 0;
/* eip-155 chain id */
if (msg->has_chain_id) {
if (msg->chain_id < 1 || msg->chain_id > MAX_CHAIN_ID) {
fsm_sendFailure(FailureType_Failure_DataError, _("Chain Id out of bounds"));
ethereum_signing_abort();
return;
}
chain_id = msg->chain_id;
} else {
chain_id = 0;
}
if (msg->has_data_length && msg->data_length > 0) {
if (!msg->has_data_initial_chunk || msg->data_initial_chunk.size == 0) {
fsm_sendFailure(FailureType_Failure_DataError, _("Data length provided, but no initial chunk"));
ethereum_signing_abort();
return;
}
/* Our encoding only supports transactions up to 2^24 bytes. To
* prevent exceeding the limit we use a stricter limit on data length.
*/
if (msg->data_length > 16000000) {
fsm_sendFailure(FailureType_Failure_DataError, _("Data length exceeds limit"));
ethereum_signing_abort();
return;
}
data_total = msg->data_length;
} else {
data_total = 0;
}
if (msg->data_initial_chunk.size > data_total) {
fsm_sendFailure(FailureType_Failure_DataError, _("Invalid size of initial chunk"));
ethereum_signing_abort();
return;
}
// safety checks
if (!ethereum_signing_check(msg)) {
fsm_sendFailure(FailureType_Failure_DataError, _("Safety check failed"));
ethereum_signing_abort();
return;
}
const TokenType *token = NULL;
// detect ERC-20 token
if (msg->to.size == 20 && msg->value.size == 0 && data_total == 68 && msg->data_initial_chunk.size == 68
&& memcmp(msg->data_initial_chunk.bytes, "\xa9\x05\x9c\xbb\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16) == 0) {
token = tokenByChainAddress(chain_id, msg->to.bytes);
}
if (token != NULL) {
layoutEthereumConfirmTx(msg->data_initial_chunk.bytes + 16, 20, msg->data_initial_chunk.bytes + 36, 32, token);
} else {
layoutEthereumConfirmTx(msg->to.bytes, msg->to.size, msg->value.bytes, msg->value.size, NULL);
}
if (!protectButton(ButtonRequestType_ButtonRequest_SignTx, false)) {
fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
ethereum_signing_abort();
return;
}
if (token == NULL && data_total > 0) {
layoutEthereumData(msg->data_initial_chunk.bytes, msg->data_initial_chunk.size, data_total);
if (!protectButton(ButtonRequestType_ButtonRequest_SignTx, false)) {
fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
ethereum_signing_abort();
return;
}
}
layoutEthereumFee(msg->value.bytes, msg->value.size,
msg->gas_price.bytes, msg->gas_price.size,
msg->gas_limit.bytes, msg->gas_limit.size, token != NULL);
if (!protectButton(ButtonRequestType_ButtonRequest_SignTx, false)) {
fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
ethereum_signing_abort();
return;
}
/* Stage 1: Calculate total RLP length */
uint32_t rlp_length = 0;
layoutProgress(_("Signing"), 0);
rlp_length += rlp_calculate_length(msg->nonce.size, msg->nonce.bytes[0]);
rlp_length += rlp_calculate_length(msg->gas_price.size, msg->gas_price.bytes[0]);
rlp_length += rlp_calculate_length(msg->gas_limit.size, msg->gas_limit.bytes[0]);
rlp_length += rlp_calculate_length(msg->to.size, msg->to.bytes[0]);
rlp_length += rlp_calculate_length(msg->value.size, msg->value.bytes[0]);
rlp_length += rlp_calculate_length(data_total, msg->data_initial_chunk.bytes[0]);
if (chain_id) {
rlp_length += rlp_calculate_length(1, chain_id);
rlp_length += rlp_calculate_length(0, 0);
rlp_length += rlp_calculate_length(0, 0);
}
/* Stage 2: Store header fields */
hash_rlp_list_length(rlp_length);
layoutProgress(_("Signing"), 100);
hash_rlp_field(msg->nonce.bytes, msg->nonce.size);
hash_rlp_field(msg->gas_price.bytes, msg->gas_price.size);
hash_rlp_field(msg->gas_limit.bytes, msg->gas_limit.size);
hash_rlp_field(msg->to.bytes, msg->to.size);
hash_rlp_field(msg->value.bytes, msg->value.size);
hash_rlp_length(data_total, msg->data_initial_chunk.bytes[0]);
hash_data(msg->data_initial_chunk.bytes, msg->data_initial_chunk.size);
data_left = data_total - msg->data_initial_chunk.size;
memcpy(privkey, node->private_key, 32);
if (data_left > 0) {
send_request_chunk();
} else {
send_signature();
}
}
void ethereum_signing_txack(EthereumTxAck *tx)
{
if (!ethereum_signing) {
fsm_sendFailure(FailureType_Failure_UnexpectedMessage, _("Not in Ethereum signing mode"));
layoutHome();
return;
}
if (tx->data_chunk.size > data_left) {
fsm_sendFailure(FailureType_Failure_DataError, _("Too much data"));
ethereum_signing_abort();
return;
}
if (data_left > 0 && (!tx->has_data_chunk || tx->data_chunk.size == 0)) {
fsm_sendFailure(FailureType_Failure_DataError, _("Empty data chunk received"));
ethereum_signing_abort();
return;
}
hash_data(tx->data_chunk.bytes, tx->data_chunk.size);
data_left -= tx->data_chunk.size;
if (data_left > 0) {
send_request_chunk();
} else {
send_signature();
}
}
void ethereum_signing_abort(void)
{
if (ethereum_signing) {
memset(privkey, 0, sizeof(privkey));
layoutHome();
ethereum_signing = false;
}
}
static void ethereum_message_hash(const uint8_t *message, size_t message_len, uint8_t hash[32])
{
struct SHA3_CTX ctx;
sha3_256_Init(&ctx);
sha3_Update(&ctx, (const uint8_t *)"\x19" "Ethereum Signed Message:\n", 26);
uint8_t varint[5];
uint32_t l = ser_length(message_len, varint);
sha3_Update(&ctx, varint, l);
sha3_Update(&ctx, message, message_len);
keccak_Final(&ctx, hash);
}
void ethereum_message_sign(EthereumSignMessage *msg, const HDNode *node, EthereumMessageSignature *resp)
{
uint8_t hash[32];
if (!hdnode_get_ethereum_pubkeyhash(node, resp->address.bytes)) {
return;
}
resp->has_address = true;
resp->address.size = 20;
ethereum_message_hash(msg->message.bytes, msg->message.size, hash);
uint8_t v;
if (ecdsa_sign_digest(&secp256k1, node->private_key, hash, resp->signature.bytes, &v, ethereum_is_canonic) != 0) {
fsm_sendFailure(FailureType_Failure_ProcessError, _("Signing failed"));
return;
}
resp->has_signature = true;
resp->signature.bytes[64] = 27 + v;
resp->signature.size = 65;
msg_write(MessageType_MessageType_EthereumMessageSignature, resp);
}
int ethereum_message_verify(EthereumVerifyMessage *msg)
{
if (msg->signature.size != 65 || msg->address.size != 20) {
fsm_sendFailure(FailureType_Failure_DataError, _("Malformed data"));
return 1;
}
uint8_t pubkey[65];
uint8_t hash[32];
ethereum_message_hash(msg->message.bytes, msg->message.size, hash);
/* v should be 27, 28 but some implementations use 0,1. We are
* compatible with both.
*/
uint8_t v = msg->signature.bytes[64];
if (v >= 27) {
v -= 27;
}
if (v >= 2 ||
ecdsa_verify_digest_recover(&secp256k1, pubkey, msg->signature.bytes, hash, v) != 0) {
return 2;
}
struct SHA3_CTX ctx;
sha3_256_Init(&ctx);
sha3_Update(&ctx, pubkey + 1, 64);
keccak_Final(&ctx, hash);
/* result are the least significant 160 bits */
if (memcmp(msg->address.bytes, hash + 12, 20) != 0) {
return 2;
}
return 0;
}
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