diff -u --recursive --exclude-from /usr/src/exclude --new-file linux.vanilla/fs/proc/generic.c linux.22-ac3/fs/proc/generic.c
--- linux.vanilla/fs/proc/generic.c	2003-06-14 00:11:39.000000000 +0100
+++ linux.22-ac3/fs/proc/generic.c	2003-07-09 13:45:05.000000000 +0100
@@ -485,12 +485,12 @@
 	return ent;
 }
 
-struct proc_dir_entry *proc_mkdir(const char *name, struct proc_dir_entry *parent)
+struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
+		struct proc_dir_entry *parent)
 {
 	struct proc_dir_entry *ent;
 
-	ent = proc_create(&parent,name,
-			  (S_IFDIR | S_IRUGO | S_IXUGO),2);
+	ent = proc_create(&parent, name, S_IFDIR | mode, 2);
 	if (ent) {
 		ent->proc_fops = &proc_dir_operations;
 		ent->proc_iops = &proc_dir_inode_operations;
@@ -503,6 +503,12 @@
 	return ent;
 }
 
+struct proc_dir_entry *proc_mkdir(const char *name,
+		struct proc_dir_entry *parent)
+{
+	return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
+}
+
 struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
 					 struct proc_dir_entry *parent)
 {
diff -purN linux-2.4.21/fs/proc/proc_tty.c linux-f/fs/proc/proc_tty.c
--- linux-2.4.21/fs/proc/proc_tty.c	2000-04-22 00:17:57.000000000 +0200
+++ linux-f/fs/proc/proc_tty.c	2003-07-14 22:10:30.000000000 +0200
@@ -16,7 +16,7 @@
 
 extern struct tty_driver *tty_drivers;	/* linked list of tty drivers */
 extern struct tty_ldisc ldiscs[];
-
+extern struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode, struct proc_dir_entry *parent);
 
 static int tty_drivers_read_proc(char *page, char **start, off_t off,
 				 int count, int *eof, void *data);
@@ -174,7 +174,13 @@ void __init proc_tty_init(void)
 	if (!proc_mkdir("tty", 0))
 		return;
 	proc_tty_ldisc = proc_mkdir("tty/ldisc", 0);
-	proc_tty_driver = proc_mkdir("tty/driver", 0);
+	/*
+	 * /proc/tty/driver/serial reveals the exact character counts for
+	 * serial links which is just too easy to abuse for inferring
+	 * password lengths and inter-keystroke timings during password
+	 * entry.
+	 */
+	proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR | S_IXUSR, 0);
 
 	create_proc_read_entry("tty/ldiscs", 0, 0, tty_ldiscs_read_proc,NULL);
 	create_proc_read_entry("tty/drivers", 0, 0, tty_drivers_read_proc,NULL);