--- linux-2.4.21/mm/mmap.c	2003-06-13 16:51:39.000000000 +0200
+++ linux-2.4.21/mm/mmap.c	2003-12-06 16:16:56.000000000 +0100
@@ -1041,6 +1041,14 @@
 	if (!len)
 		return addr;
 
+        // added by Torsten Hoefler - htor@unixer.de @06.12.2003 - make sure the adress is in bounds!
+        /* These are the first couple of lines from the patched mmap.c */
+        if ((addr + len) > TASK_SIZE || (addr + len) < addr){
+                printk("htor: somebody tried a do_brk exploit!!!\n");
+                return -EINVAL;
+        }
+        // end Additon ...
+
 	/*
 	 * mlock MCL_FUTURE?
 	 */