Index: oldkernel/linux/fs/exec.c
diff -u linux/fs/exec.c:1.1.1.1 linux/fs/exec.c:1.2
--- linux/fs/exec.c:1.1.1.1	Wed May 31 12:33:48 2000
+++ linux/fs/exec.c	Wed May 31 14:51:00 2000
@@ -214,6 +214,13 @@
 				return error;
 			if (!p)
 				break;
+			else {
+				char c;
+				/* We have to make sure the pointer is valid. */
+				error = get_user(c, p);
+				if (error)
+					return error;
+			}
 			argv++;
 			if (++i > max) return -E2BIG;
 		}