From 76a034b747bce907196b559ed93ada3dea2f582e Mon Sep 17 00:00:00 2001
From: JCW <a1q123456@users.noreply.github.com>
Date: Mon, 17 Aug 2026 16:02:35 +0100
Subject: [PATCH] WIP

---
 include/xrpl/tx/invariants/VaultInvariant.h       |  3 +++
 src/libxrpl/tx/invariants/VaultInvariant.cpp      | 14 ++++++++++++++
 src/libxrpl/tx/transactors/lending/LoanAccept.cpp | 10 ++++++++++
 src/libxrpl/tx/transactors/vault/VaultDelete.cpp  |  6 ++++++
 4 files changed, 33 insertions(+)

diff --git a/include/xrpl/tx/invariants/VaultInvariant.h b/include/xrpl/tx/invariants/VaultInvariant.h
index 136c6c4a25..aad803458e 100644
--- a/include/xrpl/tx/invariants/VaultInvariant.h
+++ b/include/xrpl/tx/invariants/VaultInvariant.h
@@ -31,6 +31,8 @@ namespace xrpl {
  * - loss unrealized does not exceed the difference between assets total and
  *   assets available
  * - assets available do not exceed assets total
+ * - assets reserved is non-negative
+ * - sum of assets available and reserved does not exceed assets total
  * - vault deposit increases assets and share issuance, and adds to:
  *   total assets, assets available, shares outstanding
  * - vault withdrawal and clawback reduce assets and share issuance, and
@@ -55,6 +57,7 @@ class ValidVault
         Number assetsAvailable = 0;
         Number assetsMaximum = 0;
         Number lossUnrealized = 0;
+        Number assetsReserved = 0;
 
         Vault static make(SLE const&);
     };
diff --git a/src/libxrpl/tx/invariants/VaultInvariant.cpp b/src/libxrpl/tx/invariants/VaultInvariant.cpp
index 7aa92e79cd..3a4ede1c08 100644
--- a/src/libxrpl/tx/invariants/VaultInvariant.cpp
+++ b/src/libxrpl/tx/invariants/VaultInvariant.cpp
@@ -44,6 +44,7 @@ ValidVault::Vault::make(SLE const& from)
     self.assetsAvailable = from.at(sfAssetsAvailable);
     self.assetsMaximum = from.at(sfAssetsMaximum);
     self.lossUnrealized = from.at(sfLossUnrealized);
+    self.assetsReserved = from.at(sfAssetsReserved);
     return self;
 }
 
@@ -495,6 +496,19 @@ ValidVault::finalize(
         result = false;
     }
 
+    if (afterVault.assetsReserved < kZero)
+    {
+        JLOG(j.fatal()) << "Invariant failed: assets reserved must be positive";
+        result = false;
+    }
+
+    if (afterVault.assetsAvailable + afterVault.assetsReserved > afterVault.assetsTotal)
+    {
+        JLOG(j.fatal()) << "Invariant failed: sum of assets available and "
+                           "reserved must not be greater than assets outstanding";
+        result = false;
+    }
+
     // Thanks to this check we can simply do `assert(!beforeVault_.empty()` when
     // enforcing invariants on transaction types other than ttVAULT_CREATE
     if (beforeVault_.empty() && txnType != ttVAULT_CREATE)
diff --git a/src/libxrpl/tx/transactors/lending/LoanAccept.cpp b/src/libxrpl/tx/transactors/lending/LoanAccept.cpp
index 62c697d156..be78429d4a 100644
--- a/src/libxrpl/tx/transactors/lending/LoanAccept.cpp
+++ b/src/libxrpl/tx/transactors/lending/LoanAccept.cpp
@@ -7,6 +7,7 @@
 #include <xrpl/ledger/View.h>
 #include <xrpl/ledger/helpers/AccountRootHelpers.h>
 #include <xrpl/ledger/helpers/LendingHelpers.h>
+#include <xrpl/ledger/helpers/TokenHelpers.h>
 #include <xrpl/protocol/AccountID.h>
 #include <xrpl/protocol/Asset.h>
 #include <xrpl/protocol/Indexes.h>
@@ -84,6 +85,15 @@ LoanAccept::preclaim(PreclaimContext const& ctx)
             ctx.view, asset, vaultPseudo, brokerPseudo, account, brokerOwner, ctx.j))
         return ter;
 
+    // Re-verify that the borrower and broker owner (the two accounts that
+    // receive funds at disbursement) are authorised to hold the vault asset.
+    // WeakAuth is used because the holdings need not exist yet; they are
+    // created at disbursement.
+    if (auto const ter = requireAuth(ctx.view, asset, account, AuthType::WeakAuth))
+        return ter;
+    if (auto const ter = requireAuth(ctx.view, asset, brokerOwner, AuthType::WeakAuth))
+        return ter;
+
     return tesSUCCESS;
 }
 
diff --git a/src/libxrpl/tx/transactors/vault/VaultDelete.cpp b/src/libxrpl/tx/transactors/vault/VaultDelete.cpp
index 497a2f2465..80c1a866e1 100644
--- a/src/libxrpl/tx/transactors/vault/VaultDelete.cpp
+++ b/src/libxrpl/tx/transactors/vault/VaultDelete.cpp
@@ -64,6 +64,12 @@ VaultDelete::preclaim(PreclaimContext const& ctx)
         return tecHAS_OBLIGATIONS;
     }
 
+    if (vault->at(sfAssetsReserved) != 0)
+    {
+        JLOG(ctx.j.debug()) << "VaultDelete: nonzero assets reserved.";
+        return tecHAS_OBLIGATIONS;
+    }
+
     // Verify we can destroy MPTokenIssuance
     auto const sleMPT = ctx.view.read(keylet::mptokenIssuance(vault->at(sfShareMPTID)));