Fix possible integer overflow

src/libraries/System.Data.Common/src/System/Data/Common/DataRecordInternal.cs

@@ -112,9 +112,9 @@ public override long GetBytes(int i, long dataIndex, byte[]? buffer, int bufferI
             cbytes = data.Length;
 
             // since arrays can't handle 64 bit values and this interface doesn't
-            // allow chunked access to data, a dataIndex outside the rang of Int32
+            // allow chunked access to data, a dataIndex outside the range of Int32
             // is invalid
-            if (dataIndex > int.MaxValue)
+            if ((ulong)dataIndex > int.MaxValue)
             {
                 throw ADP.InvalidSourceBufferIndex(cbytes, dataIndex, nameof(dataIndex));
             }
@@ -182,9 +182,9 @@ public override long GetChars(int i, long dataIndex, char[]? buffer, int bufferI
             int cchars = data.Length;
 
             // since arrays can't handle 64 bit values and this interface doesn't
-            // allow chunked access to data, a dataIndex outside the rang of Int32
+            // allow chunked access to data, a dataIndex outside the range of Int32
             // is invalid
-            if (dataIndex > int.MaxValue)
+            if ((ulong)dataIndex > int.MaxValue)
             {
                 throw ADP.InvalidSourceBufferIndex(cchars, dataIndex, nameof(dataIndex));
             }

src/libraries/System.Data.Common/tests/System/Data/Common/DataRecordInternalTest.cs

@@ -0,0 +1,40 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Xunit;
+
+namespace System.Data.Common.Tests
+{
+    public class DataRecordInternalTest
+    {
+        [Fact]
+        public void GetBytes_NegativeDataIndex_ThrowsIndexOutOfRangeException()
+        {
+            DataTable table = new DataTable();
+            table.Columns.Add("Bytes", typeof(byte[]));
+            table.Rows.Add(new byte[] { 1, 2, 3 });
+
+            using DataTableReader reader = table.CreateDataReader();
+            reader.Read();
+
+            byte[] buffer = new byte[3];
+
+            Assert.Throws<IndexOutOfRangeException>(() => reader.GetBytes(0, Int64.MinValue, buffer, 0, buffer.Length));
+        }
+
+        [Fact]
+        public void GetChars_NegativeDataIndex_ThrowsIndexOutOfRangeException()
+        {
+            DataTable table = new DataTable();
+            table.Columns.Add("Chars", typeof(char[]));
+            table.Rows.Add(new char[] { 'a', 'b', 'c' });
+
+            using DataTableReader reader = table.CreateDataReader();
+            reader.Read();
+
+            char[] buffer = new char[3];
+
+            Assert.Throws<IndexOutOfRangeException>(() => reader.GetChars(0, Int64.MinValue, buffer, 0, buffer.Length));
+        }
+    }
+}