diff -urNp linux-2.4.21/mm/mmap.c linux-2.4.21.SUSE/mm/mmap.c
--- linux-2.4.21/mm/mmap.c	2003-09-26 15:26:43.000000000 +0200
+++ linux-2.4.21.SUSE/mm/mmap.c	2003-09-26 15:30:43.000000000 +0200
@@ -1117,6 +1117,9 @@ unsigned long do_brk(unsigned long addr,
 	if (!len)
 		return addr;
 
+	if ((addr + len) > TASK_SIZE || (addr + len) < addr)
+		return -EINVAL;
+
 	/*
 	 * mlock MCL_FUTURE?
 	 */