fix: Validate account/ident type in gateway_balances (#7655)

API-CHANGELOG.md

@@ -54,6 +54,7 @@ This section contains changes targeting a future version.
 - `submit`: The `fail_hard` field now returns an error if the value is not a boolean. [#6529](https://github.com/XRPLF/rippled/pull/6529)
 - `subscribe`: The `taker` field in the `books` array now returns `actMalformed` instead of `badIssuer` if the value is not a valid account. [#6529](https://github.com/XRPLF/rippled/pull/6529)
 - Fixed a bug in `Forwarded` HTTP header parsing where the extracted IP address could be incorrect when no comma or semicolon delimiter follows the address. This could cause the server to misidentify a client's IP address when operating behind a reverse proxy. [#6529](https://github.com/XRPLF/rippled/pull/6529)
+- `gateway_balances`: The `account` and `ident` fields now return an `invalidParams` error if the value is not a string, instead of an `internal` error. [#7655](https://github.com/XRPLF/rippled/pull/7655)
 - `account_lines`: The `peer` field now returns an error if the value is not a string. [#7728](https://github.com/XRPLF/rippled/pull/7728)
 
 ## XRP Ledger server version 3.1.0

src/test/rpc/GatewayBalances_test.cpp

@@ -176,6 +176,45 @@ public:
         });
     }
 
+    void
+    testGWBInvalidAccount(FeatureBitset features)
+    {
+        testcase("Gateway Balances with non-string account/ident");
+        using namespace std::chrono_literals;
+        using namespace jtx;
+        Env env(*this, features);
+
+        Account const alice{"alice"};
+        env.fund(XRP(10000), alice);
+        env.close();
+
+        auto wsc = makeWSClient(env.app().config());
+
+        // A non-string "account" must be rejected cleanly with invalidParams
+        // rather than throwing a Json::LogicError that surfaces as internal.
+        json::Value qry;
+        qry[jss::account] = 42;
+        qry[jss::hotwallet] = alice.human();
+
+        forAllApiVersions([&, this](unsigned apiVersion) {
+            qry[jss::api_version] = apiVersion;
+            auto jv = wsc->invoke("gateway_balances", qry);
+            expect(jv[jss::status] == "error");
+            BEAST_EXPECT(jv[jss::result][jss::error] == "invalidParams");
+        });
+
+        // The same applies to a non-string "ident".
+        json::Value qry2;
+        qry2[jss::ident] = 42;
+
+        forAllApiVersions([&, this](unsigned apiVersion) {
+            qry2[jss::api_version] = apiVersion;
+            auto jv = wsc->invoke("gateway_balances", qry2);
+            expect(jv[jss::status] == "error");
+            BEAST_EXPECT(jv[jss::result][jss::error] == "invalidParams");
+        });
+    }
+
     void
     testGWBOverflow()
     {
@@ -280,6 +319,7 @@ public:
         {
             testGWB(feature);
             testGWBApiVersions(feature);
+            testGWBInvalidAccount(feature);
         }
         testGWBWithMPT();
         testGWBOverflow();

src/xrpld/rpc/handlers/account/GatewayBalances.cpp

@@ -63,6 +63,12 @@ doGatewayBalances(rpc::JsonContext& context)
     if (!(params.isMember(jss::account) || params.isMember(jss::ident)))
         return rpc::missingFieldError(jss::account);
 
+    if (params.isMember(jss::account) && !params[jss::account].isString())
+        return rpc::invalidFieldError(jss::account);
+
+    if (params.isMember(jss::ident) && !params[jss::ident].isString())
+        return rpc::invalidFieldError(jss::ident);
+
     std::string const strIdent(
         params.isMember(jss::account) ? params[jss::account].asString()
                                       : params[jss::ident].asString());