diff --git a/ChangeLog b/ChangeLog
index c6512eb812..f148096179 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2023-12-05 Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Source/NSMessagePort.m:
+	* Source/NSSocketPort.m:
+	Remove obsolete restriction on DO message length.  Add exception handler
+	to invalidate port if we are unable to allocate more memory for a very
+	large port message.
+
 2023-11-23 Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSBundle.m:
diff --git a/Source/NSMessagePort.m b/Source/NSMessagePort.m
index 70d75f7bcc..4a3b65f9ec 100644
--- a/Source/NSMessagePort.m
+++ b/Source/NSMessagePort.m
@@ -103,11 +103,6 @@ @interface NSProcessInfo (private)
 + (BOOL) _exists: (int)pid;
 @end
 
-/*
- * Largest chunk of data possible in DO
- */
-static uint32_t	maxDataLength = 32 * 1024 * 1024;
-
 #if 0
 #define	M_LOCK(X) {NSDebugMLLog(@"NSMessagePort",@"lock %@",X); [X lock];}
 #define	M_UNLOCK(X) {NSDebugMLLog(@"NSMessagePort",@"unlock %@",X); [X unlock];}
@@ -580,15 +575,20 @@ - (void) receivedEvent: (void*)data
       else
 	{
 	  want = [rData length];
-	  if (want < rWant)
+	  if (want < MAX(rWant, NETBLOCK))
 	    {
-	      want = rWant;
-	      [rData setLength: want];
-	    }
-	  if (want < NETBLOCK)
-	    {
-	      want = NETBLOCK;
-	      [rData setLength: want];
+	      want = MAX(rWant, NETBLOCK);
+	      NS_DURING
+		{
+		  [rData setLength: want];
+		}
+	      NS_HANDLER
+		{
+		  M_UNLOCK(myLock);
+		  [self invalidate];
+		  [localException raise];
+		}
+	      NS_ENDHANDLER
 	    }
 	}
 
@@ -682,14 +682,6 @@ - (void) receivedEvent: (void*)data
 			}
 		      else
 			{
-			  if (l > maxDataLength)
-			    {
-			      NSLog(@"%@ - unreasonable length (%u) for data",
-				self, l);
-			      M_UNLOCK(myLock);
-			      [self invalidate];
-			      return;
-			    }
 			  /*
 			   * If not a port or zero length data,
 			   * we discard the data read so far and fill the
@@ -705,14 +697,6 @@ - (void) receivedEvent: (void*)data
 		    }
 		  else if (rType == GSP_HEAD)
 		    {
-		      if (l > maxDataLength)
-			{
-			  NSLog(@"%@ - unreasonable length (%u) for data",
-			    self, l);
-			  M_UNLOCK(myLock);
-			  [self invalidate];
-			  return;
-			}
 		      /*
 		       * If not a port or zero length data,
 		       * we discard the data read so far and fill the
diff --git a/Source/NSSocketPort.m b/Source/NSSocketPort.m
index 6eedb276d0..83e8434526 100644
--- a/Source/NSSocketPort.m
+++ b/Source/NSSocketPort.m
@@ -139,11 +139,6 @@ static int socketError()
 }
 #endif /* !_WIN32 */
 
-/*
- * Largest chunk of data possible in DO
- */
-static uint32_t	maxDataLength = 32 * 1024 * 1024;
-
 /* Options for TLS encryption of connections
  */
 static NSDictionary     *tlsClientOptions;
@@ -883,15 +878,19 @@ - (void) receivedEventRead
   else
     {
       want = [rData length];
-      if (want < rWant)
-        {
-          want = rWant;
-          [rData setLength: want];
-        }
-      if (want < NETBLOCK)
+      if (want < MAX(rWant, NETBLOCK))
         {
-          want = NETBLOCK;
-          [rData setLength: want];
+          want = MAX(rWant, NETBLOCK);
+	  NS_DURING
+	    {
+	      [rData setLength: want];
+	    }
+	  NS_HANDLER
+	    {
+	      [self invalidate];
+	      [localException raise];
+	    }
+	  NS_ENDHANDLER
         }
     }
 
@@ -1013,13 +1012,6 @@ - (void) receivedEventRead
 		    }
 		  else
 		    {
-		      if (l > maxDataLength)
-		        {
-		          NSLog(@"%@ - unreasonable length (%u) for data",
-		        	self, l);
-		          [self invalidate];
-		          return;
-		        }
 		      /*
 		       * If not a port or zero length data,
 		       * we discard the data read so far and fill the
@@ -1035,13 +1027,6 @@ - (void) receivedEventRead
 		}
 	      else if (rType == GSP_HEAD)
 		{
-		  if (l > maxDataLength)
-		    {
-		      NSLog(@"%@ - unreasonable length (%u) for data",
-		        self, l);
-		      [self invalidate];
-		      return;
-		    }
 		  /*
 		   * If not a port or zero length data,
 		   * we discard the data read so far and fill the