legacy/signing: Ask user to confirm custom nLockTime.

legacy/firmware/CHANGELOG.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Added
 - XVG support.  [#1165]
+- Ask user to confirm custom nLockTime.
 
 ### Changed
 - Print inverted question mark for non-printable characters.

legacy/firmware/layout2.c

@@ -37,6 +37,8 @@
 #include "timer.h"
 #include "util.h"
 
+#define LOCKTIME_TIMESTAMP_MIN_VALUE 500000000
+
 #if !BITCOIN_ONLY
 
 static const char *slip44_extras(uint32_t coin_type) {
@@ -450,6 +452,25 @@ void layoutChangeCountOverThreshold(uint32_t change_count) {
                     _("Continue?"), NULL);
 }
 
+void layoutConfirmNondefaultLockTime(uint32_t lock_time,
+                                     bool lock_time_disabled) {
+  if (lock_time_disabled) {
+    layoutDialogSwipe(&bmp_icon_question, _("Cancel"), _("Confirm"), NULL,
+                      _("Warning!"), _("Locktime is set but"),
+                      _("will have no effect."), NULL, _("Continue?"), NULL);
+
+  } else {
+    char str_locktime[11] = {0};
+    snprintf(str_locktime, sizeof(str_locktime), "%" PRIu32, lock_time);
+    char *str_type = (lock_time < LOCKTIME_TIMESTAMP_MIN_VALUE) ? "blockheight:"
+                                                                : "timestamp:";
+
+    layoutDialogSwipe(&bmp_icon_question, _("Cancel"), _("Confirm"), NULL,
+                      _("Locktime for this"), _("transaction is set to"),
+                      str_type, str_locktime, _("Continue?"), NULL);
+  }
+}
+
 void layoutSignMessage(const uint8_t *msg, uint32_t len) {
   const char **str = NULL;
   if (!is_valid_ascii(msg, len)) {

legacy/firmware/layout2.h

@@ -53,6 +53,8 @@ void layoutConfirmTx(const CoinInfo *coin, uint64_t amount_out,
                      uint64_t amount_fee);
 void layoutFeeOverThreshold(const CoinInfo *coin, uint64_t fee);
 void layoutChangeCountOverThreshold(uint32_t change_count);
+void layoutConfirmNondefaultLockTime(uint32_t lock_time,
+                                     bool lock_time_disabled);
 void layoutSignMessage(const uint8_t *msg, uint32_t len);
 void layoutVerifyAddress(const CoinInfo *coin, const char *address);
 void layoutVerifyMessage(const uint8_t *msg, uint32_t len);

legacy/firmware/signing.c

@@ -75,6 +75,7 @@ static uint32_t lock_time = 0;
 static uint32_t expiry = 0;
 static uint32_t version_group_id = 0;
 static uint32_t timestamp = 0;
+static uint32_t min_sequence = 0;
 #if !BITCOIN_ONLY
 static uint32_t branch_id = 0;
 #endif
@@ -107,6 +108,10 @@ static uint32_t tx_weight;
 /* The maximum number of change-outputs allowed without user confirmation. */
 #define MAX_SILENT_CHANGE_COUNT 2
 
+/* Setting nSequence to this value for every input in a transaction disables
+   nLockTime. */
+#define SEQUENCE_FINAL 0xffffffff
+
 enum {
   SIGHASH_ALL = 1,
   SIGHASH_FORKID = 0x40,
@@ -497,6 +502,7 @@ void signing_init(const SignTx *msg, const CoinInfo *_coin,
   memcpy(&root, _root, sizeof(HDNode));
   version = msg->version;
   lock_time = msg->lock_time;
+  min_sequence = SEQUENCE_FINAL;
 
   if (!coin->overwintered) {
     if (msg->has_version_group_id) {
@@ -782,12 +788,18 @@ static bool signing_check_input(const TxInputType *txinput) {
   } else {  // single signature
     multisig_fp_mismatch = true;
   }
+
   // remember the input bip32 path
   // change addresses must use the same bip32 path as all inputs
   extract_input_bip32_path(txinput);
+
+  // remember the minimum nSequence value
+  if (txinput->sequence < min_sequence) min_sequence = txinput->sequence;
+
   // compute segwit hashPrevouts & hashSequence
   tx_prevout_hash(&hasher_prevouts, txinput);
   tx_sequence_hash(&hasher_sequence, txinput);
+
 #if !BITCOIN_ONLY
   if (coin->decred) {
     // serialize Decred prefix in Phase 1
@@ -800,6 +812,7 @@ static bool signing_check_input(const TxInputType *txinput) {
     tx_serialize_input_hash(&ti, txinput);
   }
 #endif
+
   // hash prevout and script type to check it later (relevant for fee
   // computation)
   tx_prevout_hash(&hasher_check, txinput);
@@ -914,6 +927,7 @@ static bool signing_confirm_tx(void) {
       return false;
     }
   }
+
   uint64_t fee = 0;
   if (spending <= to_spend) {
     fee = to_spend - spending;
@@ -939,6 +953,16 @@ static bool signing_confirm_tx(void) {
     }
   }
 
+  if (lock_time != 0) {
+    bool lock_time_disabled = (min_sequence == SEQUENCE_FINAL);
+    layoutConfirmNondefaultLockTime(lock_time, lock_time_disabled);
+    if (!protectButton(ButtonRequestType_ButtonRequest_SignTx, false)) {
+      fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
+      signing_abort();
+      return false;
+    }
+  }
+
   // last confirmation
   layoutConfirmTx(coin, to_spend - change_spend, fee);
   if (!protectButton(ButtonRequestType_ButtonRequest_SignTx, false)) {

tests/device_tests/test_msg_signtx_komodo.py

@@ -60,7 +60,6 @@ class TestMsgSigntxKomodo:
             script_type=proto.OutputScriptType.PAYTOADDRESS,
         )
 
-        trezor_core = client.features.model != "1"
         with client:
             client.set_expected_responses(
                 [
@@ -71,7 +70,7 @@ class TestMsgSigntxKomodo:
                     request_extra_data(0, 11, TXHASH_2807c),
                     request_output(0),
                     proto.ButtonRequest(code=B.ConfirmOutput),
-                    (trezor_core, proto.ButtonRequest(code=B.SignTx)),
+                    proto.ButtonRequest(code=B.SignTx),
                     proto.ButtonRequest(code=B.SignTx),
                     request_input(0),
                     request_output(0),
@@ -120,7 +119,6 @@ class TestMsgSigntxKomodo:
             script_type=proto.OutputScriptType.PAYTOADDRESS,
         )
 
-        trezor_core = client.features.model != "1"
         with client:
             client.set_expected_responses(
                 [
@@ -133,7 +131,7 @@ class TestMsgSigntxKomodo:
                     proto.ButtonRequest(code=B.ConfirmOutput),
                     request_output(1),
                     proto.ButtonRequest(code=B.ConfirmOutput),
-                    (trezor_core, proto.ButtonRequest(code=B.SignTx)),
+                    proto.ButtonRequest(code=B.SignTx),
                     proto.ButtonRequest(code=B.SignTx),
                     request_input(0),
                     request_output(0),