Subject: [PATCH v2] drivers/net/usb/hso.c: prevent reading uninitialized memory

From: Dan Rosenberg <[email-masked]>
Date: Wed, 15 Sep 2010 17:43:28 -0400

Fixed formatting (tabs and line breaks).

The TIOCGICOUNT device ioctl allows unprivileged users to read
uninitialized stack memory, because the "reserved" member of the
serial_icounter_struct struct declared on the stack in hso_get_count()
is not altered or zeroed before being copied back to the user.  This
patch takes care of it.

Signed-off-by: Dan Rosenberg <[email-masked]>

--- linux-2.6.35.4.orig/drivers/net/usb/hso.c	2010-08-26 19:47:12.000000000 -0400
+++ linux-2.6.35.4/drivers/net/usb/hso.c	2010-09-14 21:26:18.477585183 -0400
@@ -1653,6 +1653,8 @@ static int hso_get_count(struct hso_seri
 	struct uart_icount cnow;
 	struct hso_tiocmget  *tiocmget = serial->tiocmget;
 
+	memset(&icount, 0, sizeof(struct serial_icounter_struct));
+
 	if (!tiocmget)
 		 return -ENOENT;
 	spin_lock_irq(&serial->serial_lock);