From e3dd33ceee8f803510cbd0debb8ed55fef4007e8 Mon Sep 17 00:00:00 2001
From: Stanislav Bezkorovainyi <stanislavbezkor@gmail.com>
Date: Mon, 10 Feb 2025 11:07:54 +0100
Subject: [PATCH] Fix token fetching (#1245)

Co-authored-by: nikitastupin-matterlabs <178824211+nikitastupin-matterlabs@users.noreply.github.com>
---
 .../contracts/upgrades/L1GatewayBase.sol      | 54 +++++++++++++++----
 1 file changed, 43 insertions(+), 11 deletions(-)

diff --git a/l1-contracts/contracts/upgrades/L1GatewayBase.sol b/l1-contracts/contracts/upgrades/L1GatewayBase.sol
index 16a56253a..fa1126143 100644
--- a/l1-contracts/contracts/upgrades/L1GatewayBase.sol
+++ b/l1-contracts/contracts/upgrades/L1GatewayBase.sol
@@ -12,10 +12,14 @@ import {ZKChainStorage} from "../state-transition/chain-deps/ZKChainStorage.sol"
 import {L2WrappedBaseTokenStore} from "../bridge/L2WrappedBaseTokenStore.sol";
 import {IERC20Metadata} from "@openzeppelin/contracts-v4/token/ERC20/extensions/IERC20Metadata.sol";
 
+import {UnsafeBytes} from "../common/libraries/UnsafeBytes.sol";
+
 /// @title L1GatewayBase
 /// @author Matter Labs
 /// @custom:security-contact security@matterlabs.dev
 abstract contract L1GatewayBase {
+    using UnsafeBytes for bytes;
+
     /// @notice The function to retrieve the chain-specific upgrade data.
     /// @param s The pointer to the storage of the chain.
     /// @param _wrappedBaseTokenStore The address of the `L2WrappedBaseTokenStore` contract.
@@ -43,15 +47,23 @@ abstract contract L1GatewayBase {
             baseTokenName = string("Ether");
             baseTokenSymbol = string("ETH");
         } else {
-            try this.getTokenName(_baseTokenAddress) returns (string memory name) {
-                baseTokenName = name;
-            } catch {
+            (string memory stringResult, bool success) = _safeCallTokenMetadata(
+                _baseTokenAddress,
+                abi.encodeCall(IERC20Metadata.name, ())
+            );
+            if (success) {
+                baseTokenName = stringResult;
+            } else {
                 baseTokenName = string("Base Token");
             }
 
-            try this.getTokenSymbol(_baseTokenAddress) returns (string memory symbol) {
-                baseTokenSymbol = symbol;
-            } catch {
+            (stringResult, success) = _safeCallTokenMetadata(
+                _baseTokenAddress,
+                abi.encodeCall(IERC20Metadata.symbol, ())
+            );
+            if (success) {
+                baseTokenSymbol = stringResult;
+            } else {
                 // "BT" is an acronym for "Base Token"
                 baseTokenSymbol = string("BT");
             }
@@ -69,11 +81,31 @@ abstract contract L1GatewayBase {
         return abi.encode(additionalForceDeploymentsData);
     }
 
-    function getTokenName(address _token) external view returns (string memory) {
-        return IERC20Metadata(_token).name();
-    }
+    /// @notice Calls a token's metadata method.
+    /// @dev For the sake of simplicity, we expect that either of the
+    /// following is true:
+    /// 1. The token does not support metadata methods
+    /// 2. The token supports it and returns a `bytes32` string there.
+    /// 3. The token supports it and returns a correct `string` as a returndata.
+    ///
+    /// For all other cases, this function will panic and so such chains would not be
+    /// deployable.
+    function _safeCallTokenMetadata(address _token, bytes memory data) internal view returns (string memory, bool) {
+        // We are not afraid if token returns large calldata, since it affects
+        // only the deployment of the chain that uses such a malicious token.
+        (bool callSuccess, bytes memory returnData) = _token.staticcall(data);
+
+        // The failed call most likely means that this method is not supported.
+        if (!callSuccess) {
+            return ("", false);
+        }
+
+        // This case covers non-standard tokens, such as Maker (MKR), that return `bytes32` instead of `string`
+        if (returnData.length == 32) {
+            return ("", false);
+        }
 
-    function getTokenSymbol(address _token) external view returns (string memory) {
-        return IERC20Metadata(_token).symbol();
+        // Note, that the following line will panic in case the token has more non-standard behavior.
+        return (abi.decode(returnData, (string)), true);
     }
 }