Merge pull request #445 from Cypherock/feat/verify-fetched-wallet/PRF…

…-6557

feat(core): Verify fetched wallets

src/card_operations/card_fetch_share.c

@@ -65,6 +65,7 @@
 #include "card_internal.h"
 #include "card_utils.h"
 #include "constant_texts.h"
+#include "core_error.h"
 #include "flash_api.h"
 #include "nfc.h"
 #include "ui_screens.h"
@@ -85,13 +86,27 @@ extern Wallet_shamir_data wallet_shamir_data;
 /*****************************************************************************
  * STATIC FUNCTION PROTOTYPES
  *****************************************************************************/
+/**
+ * The function `verify_fetched_wallet` compares the values of a `wallet` object
+ * with the values of a `flash_wallet` object and returns a boolean indicating
+ * whether they are equal.
+ *
+ * @param xcor The x-coordinate of the wallet share, this variable represents
+ * the share index fetched from the last tapped card.
+ *
+ * @return a boolean value, which indicates whether the fetched wallet matches
+ * the expected values.
+ */
+static bool verify_fetched_wallet(uint8_t xcor);
+
 /**
  * @brief Helper function that copies wallet share retrieved from X1 card onto
  * the RAM
  *
- * @param xcor The x-coordinate of the wallet share
+ * @param xcor The x-coordinate of the wallet share, this variable represents
+ * the share index fetched from the last tapped card.
  */
-static void _handle_retrieve_wallet_success(uint8_t xcor);
+static bool _handle_retrieve_wallet_success(uint8_t xcor);
 
 /*****************************************************************************
  * STATIC VARIABLES
@@ -105,16 +120,66 @@ static uint8_t remaining_cards;
 /*****************************************************************************
  * STATIC FUNCTIONS
  *****************************************************************************/
-static void _handle_retrieve_wallet_success(uint8_t xcor) {
-  if (WALLET_IS_ARBITRARY_DATA(wallet.wallet_info))
+
+static bool verify_fetched_wallet(uint8_t xcor) {
+  Flash_Wallet *flash_wallet = NULL;
+  bool status =
+      get_flash_wallet_by_name((const char *)wallet.wallet_name, &flash_wallet);
+
+  ASSERT(SUCCESS == status && NULL != flash_wallet);
+
+  bool compare_status =
+      (0 == memcmp(wallet.wallet_id, flash_wallet->wallet_id, WALLET_ID_SIZE));
+  compare_status &=
+      (0 == memcmp(wallet.wallet_name, flash_wallet->wallet_name, NAME_SIZE));
+  compare_status &= (wallet.wallet_info == flash_wallet->wallet_info);
+
+  /**
+   * For wallets with device share present on flash, fetched wallet nonce is
+   * compared with wallet nonce on flash. In case of sync wallet, the wallet
+   * share and encryption data is written on flash after verification. For
+   * verifying the wallets in this case, we compare wallet nonce fetched from
+   * the two cards.
+   */
+  if (VALID_WALLET_WITHOUT_DEVICE_SHARE != flash_wallet->state) {
+    // Wallet nonce present on flash, so compare current wallet nonce with flash
+    // wallet nonce.
+    uint8_t wallet_nonce[NONCE_SIZE] = {0};
+    ASSERT(SUCCESS ==
+           get_flash_wallet_nonce_by_name(
+               (const char *)flash_wallet->wallet_name, wallet_nonce));
+    compare_status &=
+        (0 == memcmp(wallet.wallet_share_with_mac_and_nonce + BLOCK_SIZE,
+                     wallet_nonce,
+                     NONCE_SIZE));
+  } else if (0 < xcor) {
+    // Compare nonce from current wallet with nonce of wallet previously
+    // fetched.
+    compare_status &=
+        (0 == memcmp(wallet.wallet_share_with_mac_and_nonce + BLOCK_SIZE,
+                     wallet_shamir_data.share_encryption_data[xcor - 1],
+                     NONCE_SIZE));
+  }
+  return compare_status;
+}
+
+static bool _handle_retrieve_wallet_success(uint8_t xcor) {
+  if (!verify_fetched_wallet(xcor)) {
+    LOG_ERROR("Verification failed xxx39");
+    return false;
+  }
+
+  if (WALLET_IS_ARBITRARY_DATA(wallet.wallet_info)) {
     memcpy(((uint8_t *)wallet_shamir_data.arbitrary_data_shares) +
                xcor * wallet.arbitrary_data_size,
            wallet.arbitrary_data_share,
            wallet.arbitrary_data_size);
-  else
+  } else {
     memcpy(wallet_shamir_data.mnemonic_shares[xcor],
            wallet.wallet_share_with_mac_and_nonce,
            BLOCK_SIZE);
+  }
+
   memcpy(wallet_shamir_data.share_encryption_data[xcor],
          wallet.wallet_share_with_mac_and_nonce + BLOCK_SIZE,
          PADDED_NONCE_SIZE + WALLET_MAC_SIZE);
@@ -123,6 +188,8 @@ static void _handle_retrieve_wallet_success(uint8_t xcor) {
           sizeof(wallet.wallet_share_with_mac_and_nonce));
 
   wallet_shamir_data.share_x_coords[xcor] = wallet.xcor;
+
+  return true;
 }
 
 /*****************************************************************************
@@ -160,7 +227,14 @@ card_error_type_e card_fetch_share(const card_fetch_share_config_t *config,
 
       if (card_data.nfc_data.status == SW_NO_ERROR) {
         remaining_cards = card_data.nfc_data.acceptable_cards;
-        _handle_retrieve_wallet_success(config->xcor);
+        if (!_handle_retrieve_wallet_success(config->xcor)) {
+          card_data.error_type = CARD_OPERATION_VERIFICATION_FAILED;
+          card_data.nfc_data.status = SW_RECORD_NOT_FOUND;
+          mark_core_error_screen(
+              ui_text_wallet_verification_failed_in_reconstruction, true);
+          break;
+        }
+
         buzzer_start(BUZZER_DURATION);
 
         if (false == config->operation.skip_card_removal) {

src/card_operations/card_operation_typedefs.h

@@ -38,6 +38,9 @@ typedef enum card_errors_type {
   CARD_OPERATION_RETAP_BY_USER_REQUIRED, /** Errors that occur due to user
                                             mistakes, like wrong card number or
                                             card of wrong family tapped */
+  CARD_OPERATION_VERIFICATION_FAILED, /** Error occuring when wallet present on
+                                         card is different from the wallet
+                                         expected*/
   CARD_OPERATION_ABORT_OPERATION, /** Error occurring due to internal handling
                                      of NFC or card communication. These errors
                                      can be associated to @ref