Ensure vault asset cap is not exceeded (#6124)

src/test/app/Loan_test.cpp

@@ -3590,6 +3590,26 @@ protected:
                     fee(env.current()->fees().base * 5));
             },
             CaseArgs{.requireAuth = true, .authorizeBorrower = true});
+
+        testCase(
+            [&, this](Env& env, BrokerInfo const& broker, auto&) {
+                using namespace loan;
+                Number const principalRequest = broker.asset(1'000).value();
+                Vault vault{env};
+                auto tx = vault.set({.owner = lender, .id = broker.vaultID});
+                tx[sfAssetsMaximum] = BrokerParameters::defaults().vaultDeposit;
+                env(tx);
+                env.close();
+
+                testcase("Vault maximum value exceeded");
+                env(set(issuer, broker.brokerID, principalRequest),
+                    counterparty(lender),
+                    interestRate(TenthBips32(10'000)),
+                    sig(sfCounterpartySignature, lender),
+                    fee(env.current()->fees().base * 5),
+                    ter(tecLIMIT_EXCEEDED));
+            },
+            nullptr);
     }
 
     void

src/xrpld/app/tx/detail/LoanSet.cpp

@@ -407,6 +407,17 @@ LoanSet::doApply()
         vaultScale,
         j_);
 
+    LoanState const state = constructLoanState(
+        properties.totalValueOutstanding,
+        principalRequested,
+        properties.managementFeeOwedToBroker);
+
+    if (vaultSle->at(sfAssetsMaximum) != 0 &&
+        vaultTotalProxy + state.interestDue > vaultSle->at(sfAssetsMaximum))
+    {
+        JLOG(j_.warn()) << "Loan would exceed the maximum assets of the vault";
+        return tecLIMIT_EXCEEDED;
+    }
     // Check that relevant values won't lose precision. This is mostly only
     // relevant for IOU assets.
     {
@@ -449,11 +460,6 @@ LoanSet::doApply()
         // LCOV_EXCL_STOP
     }
 
-    LoanState const state = constructLoanState(
-        properties.totalValueOutstanding,
-        principalRequested,
-        properties.managementFeeOwedToBroker);
-
     auto const originationFee = tx[~sfLoanOriginationFee].value_or(Number{});
 
     auto const loanAssetsToBorrower = principalRequested - originationFee;