Improve error message returned in swap

src_features/signTx/logic_signTx.c

@@ -11,6 +11,7 @@
 #include "crypto_helpers.h"
 #include "format.h"
 #include "manage_asset_info.h"
+#include "handle_swap_sign_transaction.h"
 
 static bool g_use_standard_ui;
 
@@ -322,6 +323,42 @@ static int strcasecmp_workaround(const char *str1, const char *str2) {
     return 0;
 }
 
+#define ERROR_WRONG_AMOUNT            0x01
+#define ERROR_WRONG_DESTINATION       0x02
+#define ERROR_WRONG_FEES              0x03
+#define ERROR_WRONG_METHOD            0x04
+#define ERROR_CROSSCHAIN_WRONG_MODE   0x05
+#define ERROR_CROSSCHAIN_WRONG_METHOD 0x06
+#define ERROR_GENERIC                 0xFF
+
+static void send_swap_error(uint8_t error_code, const char *str1, const char *str2) {
+    uint32_t tx = 0;
+    PRINTF("APDU_RESPONSE_MODE_CHECK_FAILED: 0x%x\n", error_code);
+    // Set RAPDU error codes
+    G_io_apdu_buffer[tx++] = error_code;
+    G_io_apdu_buffer[tx++] = 0x00;
+    // Set RAPDU error message
+    if (str1 != NULL) {
+        PRINTF("Expected %s\n", str1);
+        memmove(G_io_apdu_buffer + tx, str1, strlen((const char *) str1));
+        tx += strlen((const char *) str1);
+    }
+    if (str2 != NULL) {
+        PRINTF("Received %s\n", str2);
+        G_io_apdu_buffer[tx++] = '#';
+        memmove(G_io_apdu_buffer + tx, str2, strlen((const char *) str2));
+        tx += strlen((const char *) str2);
+    }
+    // Set RAPDU status word
+    U2BE_ENCODE(G_io_apdu_buffer, tx, APDU_RESPONSE_MODE_CHECK_FAILED);
+    tx += 2;
+    // Send RAPDU
+    io_exchange(CHANNEL_APDU | IO_RETURN_AFTER_TX, tx);
+    // In case of success, the apdu is sent immediately and eth exits
+    // Reaching this code means we encountered an error
+    finalize_exchange_sign_transaction(false);
+}
+
 __attribute__((noinline)) static uint16_t finalize_parsing_helper(void) {
     char displayBuffer[50];
     uint8_t decimals = WEI_TO_ETHER;
@@ -452,19 +489,18 @@ __attribute__((noinline)) static uint16_t finalize_parsing_helper(void) {
         G_swap_response_ready = true;
     }
 
-    // User has just validated a swap but ETH received apdus about a non standard plugin / contract
-    if (G_called_from_swap && !g_use_standard_ui) {
-        PRINTF("APDU_RESPONSE_MODE_CHECK_FAILED, G_called_from_swap\n");
-        return APDU_RESPONSE_MODE_CHECK_FAILED;
-    }
-
-    // Specific calldata check when in swap mode
     if (G_called_from_swap) {
+        // User has just validated a swap but ETH received apdus about a non standard plugin /
+        // contract
+        if (!g_use_standard_ui) {
+            send_swap_error(ERROR_GENERIC, "No Standard UI", NULL);
+            return 0;
+        }
         // Two success cases: we are in standard mode and no calldata was received
         // We are in crosschain mode and the correct calldata has been received
         if (G_swap_mode != SWAP_MODE_STANDARD && G_swap_mode != SWAP_MODE_CROSSCHAIN_SUCCESS) {
-            PRINTF("Error: G_swap_mode %d refused\n", G_swap_mode);
-            return APDU_RESPONSE_MODE_CHECK_FAILED;
+            send_swap_error(ERROR_CROSSCHAIN_WRONG_MODE, "Wrong swap mode", NULL);
+            return APDU_NO_RESPONSE;
         }
     }
 
@@ -490,8 +526,8 @@ __attribute__((noinline)) static uint16_t finalize_parsing_helper(void) {
         if (G_called_from_swap) {
             // Ensure the values are the same that the ones that have been previously validated
             if (strcasecmp_workaround(strings.common.toAddress, displayBuffer) != 0) {
-                PRINTF("APDU_RESPONSE_MODE_CHECK_FAILED, address check failed\n");
-                return APDU_RESPONSE_MODE_CHECK_FAILED;
+                send_swap_error(ERROR_WRONG_DESTINATION, strings.common.toAddress, displayBuffer);
+                return APDU_NO_RESPONSE;
             }
         } else {
             strlcpy(strings.common.toAddress, displayBuffer, sizeof(strings.common.toAddress));
@@ -513,10 +549,8 @@ __attribute__((noinline)) static uint16_t finalize_parsing_helper(void) {
         if (G_called_from_swap) {
             // Ensure the values are the same that the ones that have been previously validated
             if (strcmp(strings.common.fullAmount, displayBuffer) != 0) {
-                PRINTF("APDU_RESPONSE_MODE_CHECK_FAILED, amount check failed\n");
-                PRINTF("Expected %s\n", strings.common.fullAmount);
-                PRINTF("Received %s\n", displayBuffer);
-                return APDU_RESPONSE_MODE_CHECK_FAILED;
+                send_swap_error(ERROR_WRONG_AMOUNT, strings.common.fullAmount, displayBuffer);
+                return APDU_NO_RESPONSE;
             }
         } else {
             strlcpy(strings.common.fullAmount, displayBuffer, sizeof(strings.common.fullAmount));
@@ -535,10 +569,8 @@ __attribute__((noinline)) static uint16_t finalize_parsing_helper(void) {
     if (G_called_from_swap) {
         // Ensure the values are the same that the ones that have been previously validated
         if (strcmp(strings.common.maxFee, displayBuffer) != 0) {
-            PRINTF("APDU_RESPONSE_MODE_CHECK_FAILED, fees check failed\n");
-            PRINTF("Expected %s\n", strings.common.maxFee);
-            PRINTF("Received %s\n", displayBuffer);
-            return APDU_RESPONSE_MODE_CHECK_FAILED;
+            send_swap_error(ERROR_WRONG_FEES, strings.common.maxFee, displayBuffer);
+            return APDU_NO_RESPONSE;
         }
     } else {
         strlcpy(strings.common.maxFee, displayBuffer, sizeof(strings.common.maxFee));