From ab715a94a7a1ea6d103cfc2ed59c03d4a4f7018c Mon Sep 17 00:00:00 2001
From: zzz <zzz@i2pmail.org>
Date: Wed, 5 Aug 2026 16:06:08 -0400
Subject: [PATCH] NTCP: Catch unchecked BufferOverflowException on read() call,
 unknown cause

reported 2x by: postman
---
 .../net/i2p/router/transport/ntcp/EventPumper.java    | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/router/java/src/net/i2p/router/transport/ntcp/EventPumper.java b/router/java/src/net/i2p/router/transport/ntcp/EventPumper.java
index 99ea83572..6d441ea2e 100644
--- a/router/java/src/net/i2p/router/transport/ntcp/EventPumper.java
+++ b/router/java/src/net/i2p/router/transport/ntcp/EventPumper.java
@@ -6,6 +6,7 @@ import java.net.Inet6Address;
 import java.net.InetSocketAddress;
 import java.nio.ByteBuffer;
 import java.nio.Buffer;
+import java.nio.BufferOverflowException;
 import java.nio.channels.CancelledKeyException;
 import java.nio.channels.ClosedChannelException;
 import java.nio.channels.ClosedSelectorException;
@@ -782,6 +783,16 @@ class EventPumper implements Runnable {
             clearInterest(key, SelectionKey.OP_READ);
             if (_log.shouldLog(Log.WARN))
                 _log.warn("error reading on " + con, nyce);
+        } catch (BufferOverflowException boe) {
+            // Rare unchecked exception on read() call, unknown cause
+            // Not even listed on SocketChannel.read() javadoc
+            // Do not release the buf, maybe it was in the pool twice?
+            // We assume this is fatal for the con so we close it.
+            clearInterest(key, SelectionKey.OP_READ);
+            con.close();
+            _context.statManager().addRateData("ntcp.readError", 1);
+            if (_log.shouldWarn())
+                _log.warn("error reading on " + con, boe);
         }
     }