From 5a643b1a7fb7766aa1af1eefe710c2d08352d0ab Mon Sep 17 00:00:00 2001
From: Shawn Xie <35279399+shawnxie999@users.noreply.github.com>
Date: Mon, 27 Apr 2026 14:36:54 -0400
Subject: [PATCH] fix: assorted safety checks (#7030)

---
 .../tx/transactors/token/ConfidentialMPTClawback.cpp |  7 ++++++-
 .../transactors/token/ConfidentialMPTConvertBack.cpp | 12 +++++++++---
 .../tx/transactors/token/ConfidentialMPTSend.cpp     |  4 ++++
 src/test/app/ConfidentialTransfer_test.cpp           |  8 ++++++++
 4 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/src/libxrpl/tx/transactors/token/ConfidentialMPTClawback.cpp b/src/libxrpl/tx/transactors/token/ConfidentialMPTClawback.cpp
index cd5bdf2937..5018a93c3f 100644
--- a/src/libxrpl/tx/transactors/token/ConfidentialMPTClawback.cpp
+++ b/src/libxrpl/tx/transactors/token/ConfidentialMPTClawback.cpp
@@ -95,7 +95,8 @@ ConfidentialMPTClawback::preclaim(PreclaimContext const& ctx)
 
     // Sanity check: claw amount can not exceed confidential outstanding amount
     auto const amount = ctx.tx[sfMPTAmount];
-    if (amount > (*sleIssuance)[~sfConfidentialOutstandingAmount].value_or(0))
+    if (amount > (*sleIssuance)[~sfConfidentialOutstandingAmount].value_or(0) ||
+        amount > (*sleIssuance)[sfOutstandingAmount])
         return tecINSUFFICIENT_FUNDS;
 
     auto const contextHash =
@@ -162,10 +163,14 @@ ConfidentialMPTClawback::doApply()
 
     // Decrease Global Confidential Outstanding Amount
     auto const oldCOA = (*sleIssuance)[sfConfidentialOutstandingAmount];
+    if (clawAmount > oldCOA)
+        return tecINTERNAL;  // LCOV_EXCL_LINE
     (*sleIssuance)[sfConfidentialOutstandingAmount] = oldCOA - clawAmount;
 
     // Decrease Global Total Outstanding Amount
     auto const oldOA = (*sleIssuance)[sfOutstandingAmount];
+    if (clawAmount > oldOA)
+        return tecINTERNAL;  // LCOV_EXCL_LINE
     (*sleIssuance)[sfOutstandingAmount] = oldOA - clawAmount;
 
     view().update(sleHolderMPToken);
diff --git a/src/libxrpl/tx/transactors/token/ConfidentialMPTConvertBack.cpp b/src/libxrpl/tx/transactors/token/ConfidentialMPTConvertBack.cpp
index 66b83a1d8f..c28b70078f 100644
--- a/src/libxrpl/tx/transactors/token/ConfidentialMPTConvertBack.cpp
+++ b/src/libxrpl/tx/transactors/token/ConfidentialMPTConvertBack.cpp
@@ -139,7 +139,8 @@ ConfidentialMPTConvertBack::preclaim(PreclaimContext const& ctx)
     if (!sleIssuance)
         return tecOBJECT_NOT_FOUND;
 
-    if (!sleIssuance->isFlag(lsfMPTCanConfidentialAmount))
+    if (!sleIssuance->isFlag(lsfMPTCanConfidentialAmount) ||
+        !sleIssuance->isFieldPresent(sfIssuerEncryptionKey))
         return tecNO_PERMISSION;
 
     bool const hasAuditor = ctx.tx.isFieldPresent(sfAuditorEncryptedAmount);
@@ -209,9 +210,14 @@ ConfidentialMPTConvertBack::doApply()
 
     // Converting back increases regular balance and decreases confidential
     // outstanding. This is the inverse of Convert.
+    if (amt > maxMPTokenAmount - amtToConvertBack)
+        return tecINTERNAL;  // LCOV_EXCL_LINE
     (*sleMptoken)[sfMPTAmount] = amt + amtToConvertBack;
-    (*sleIssuance)[sfConfidentialOutstandingAmount] =
-        (*sleIssuance)[sfConfidentialOutstandingAmount] - amtToConvertBack;
+
+    auto const coa = (*sleIssuance)[~sfConfidentialOutstandingAmount].value_or(0);
+    if (coa < amtToConvertBack)
+        return tecINTERNAL;  // LCOV_EXCL_LINE
+    (*sleIssuance)[sfConfidentialOutstandingAmount] = coa - amtToConvertBack;
 
     std::optional<Slice> const auditorEc = ctx_.tx[~sfAuditorEncryptedAmount];
 
diff --git a/src/libxrpl/tx/transactors/token/ConfidentialMPTSend.cpp b/src/libxrpl/tx/transactors/token/ConfidentialMPTSend.cpp
index 6fe98c7687..c9b9409452 100644
--- a/src/libxrpl/tx/transactors/token/ConfidentialMPTSend.cpp
+++ b/src/libxrpl/tx/transactors/token/ConfidentialMPTSend.cpp
@@ -37,6 +37,10 @@ ConfidentialMPTSend::preflight(PreflightContext const& ctx)
     if (account == ctx.tx[sfDestination])
         return temMALFORMED;
 
+    // Issuer cannot be the destination
+    if (ctx.tx[sfDestination] == issuer)
+        return temMALFORMED;
+
     // Check the length of the encrypted amounts
     if (ctx.tx[sfSenderEncryptedAmount].length() != ecGamalEncryptedTotalLength ||
         ctx.tx[sfDestinationEncryptedAmount].length() != ecGamalEncryptedTotalLength ||
diff --git a/src/test/app/ConfidentialTransfer_test.cpp b/src/test/app/ConfidentialTransfer_test.cpp
index 638801c839..fb36b3d6b2 100644
--- a/src/test/app/ConfidentialTransfer_test.cpp
+++ b/src/test/app/ConfidentialTransfer_test.cpp
@@ -2111,6 +2111,14 @@ class ConfidentialTransfer_test : public beast::unit_test::suite
                 .err = temMALFORMED,
             });
 
+            // can not send to issuer
+            mptAlice.send({
+                .account = bob,
+                .dest = alice,
+                .amt = 10,
+                .err = temMALFORMED,
+            });
+
             // sender encrypted amount wrong length
             mptAlice.send({
                 .account = bob,