fix(legacy): Sync input sanitization with trezor-core.

legacy/firmware/signing.c

@@ -1436,8 +1436,8 @@ void signing_init(const SignTx *msg, const CoinInfo *_coin, const HDNode *_root,
 
 static bool signing_validate_input(const TxInputType *txinput) {
   if (txinput->prev_hash.size != 32) {
-    fsm_sendFailure(FailureType_Failure_ProcessError,
-                    _("Encountered invalid prevhash"));
+    fsm_sendFailure(FailureType_Failure_DataError,
+                    _("Provided prev_hash is invalid."));
     signing_abort();
     return false;
   }
@@ -1450,7 +1450,22 @@ static bool signing_validate_input(const TxInputType *txinput) {
     return false;
   }
 
+  if (!txinput->has_multisig &&
+      txinput->script_type == InputScriptType_SPENDMULTISIG) {
+    fsm_sendFailure(FailureType_Failure_DataError,
+                    _("Multisig details required."));
+    signing_abort();
+    return false;
+  }
+
   if (is_internal_input_script_type(txinput->script_type)) {
+    if (txinput->address_n_count == 0) {
+      fsm_sendFailure(FailureType_Failure_DataError,
+                      _("Missing address_n field."));
+      signing_abort();
+      return false;
+    }
+
     if (txinput->has_script_pubkey) {
       // scriptPubKey should only be provided for external inputs
       fsm_sendFailure(FailureType_Failure_DataError,
@@ -1487,6 +1502,14 @@ static bool signing_validate_input(const TxInputType *txinput) {
     return false;
   }
 
+  if (!coin->decred && txinput->has_decred_tree) {
+    fsm_sendFailure(
+        FailureType_Failure_DataError,
+        _("Decred details provided but Decred coin not specified."));
+    signing_abort();
+    return false;
+  }
+
   if (is_segwit_input_script_type(txinput->script_type)) {
     if (!coin->has_segwit) {
       fsm_sendFailure(FailureType_Failure_DataError,
@@ -1520,8 +1543,8 @@ static bool signing_validate_input(const TxInputType *txinput) {
     }
 
     if (txinput->orig_hash.size != 32) {
-      fsm_sendFailure(FailureType_Failure_ProcessError,
-                      _("Encountered invalid orig_hash"));
+      fsm_sendFailure(FailureType_Failure_DataError,
+                      _("Provided orig_hash is invalid."));
       signing_abort();
       return false;
     }
@@ -1530,6 +1553,25 @@ static bool signing_validate_input(const TxInputType *txinput) {
   return true;
 }
 
+static bool signing_validate_prev_input(const TxInputType *txinput) {
+  if (txinput->prev_hash.size != 32) {
+    fsm_sendFailure(FailureType_Failure_DataError,
+                    _("Provided prev_hash is invalid."));
+    signing_abort();
+    return false;
+  }
+
+  if (!coin->decred && txinput->has_decred_tree) {
+    fsm_sendFailure(
+        FailureType_Failure_DataError,
+        _("Decred details provided but Decred coin not specified."));
+    signing_abort();
+    return false;
+  }
+
+  return true;
+}
+
 static bool signing_validate_output(TxOutputType *txoutput) {
   if (txoutput->has_multisig &&
       !is_multisig_output_script_type(txoutput->script_type)) {
@@ -3657,7 +3699,7 @@ void signing_txack(TransactionType *tx) {
       }
       return;
     case STAGE_REQUEST_3_PREV_INPUT:
-      if (!signing_validate_input(&tx->inputs[0])) {
+      if (!signing_validate_prev_input(&tx->inputs[0])) {
         return;
       }
       progress_substep++;

legacy/firmware/transaction.c

@@ -210,8 +210,7 @@ bool compute_address(const CoinInfo *coin, InputScriptType script_type,
     ecdsa_get_address_segwit_p2sh(
         node->public_key, coin->address_type_p2sh, coin->curve->hasher_pubkey,
         coin->curve->hasher_base58, address, MAX_ADDR_SIZE);
-  } else if (script_type == InputScriptType_SPENDADDRESS ||
-             script_type == InputScriptType_SPENDMULTISIG) {
+  } else if (script_type == InputScriptType_SPENDADDRESS) {
 #if !BITCOIN_ONLY
     if (coin->cashaddr_prefix) {
       ecdsa_get_address_raw(node->public_key, CASHADDR_P2KH | CASHADDR_160,

tests/device_tests/bitcoin/test_signtx_prevhash.py

@@ -63,14 +63,11 @@ def hash_tx(data: bytes) -> bytes:
 
 
 def _check_error_message(value: bytes, model: str, message: str):
-    if model != "1":
-        assert message == "Provided prev_hash is invalid."
-
     # T1 has several possible errors
-    elif len(value) > 32:
+    if model == "1" and len(value) > 32:
         assert message.endswith("bytes overflow")
     else:
-        assert message.endswith("Encountered invalid prevhash")
+        assert message.endswith("Provided prev_hash is invalid.")
 
 
 with_bad_prevhashes = pytest.mark.parametrize(