[02/80] USB: serial/mos*: prevent reading uninitialized stack memory

Greg KH
2010-09-24T16:27:53Z

From: Dan Rosenberg <drosenberg@vsecurity.com>

commit a0846f1868b11cd827bdfeaf4527d8b1b1c0b098 upstream.

The TIOCGICOUNT device ioctl in both mos7720.c and mos7840.c allows
unprivileged users to read uninitialized stack memory, because the
"reserved" member of the serial_icounter_struct struct declared on the
stack is not altered or zeroed before being copied back to the user.
This patch takes care of it.

Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/usb/serial/mos7720.c | 3 +++
drivers/usb/serial/mos7840.c | 3 +++
2 files changed, 6 insertions(+)

--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -2024,6 +2024,9 @@ static int mos7720_ioctl(struct tty_stru

case TIOCGICOUNT:
cnow = mos7720_port->icount;
+
+ memset(&icount, 0, sizeof(struct serial_icounter_struct));
+
icount.cts = cnow.cts;
icount.dsr = cnow.dsr;
icount.rng = cnow.rng;
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -2285,6 +2285,9 @@ static int mos7840_ioctl(struct tty_stru
case TIOCGICOUNT:
cnow = mos7840_port->icount;
smp_rmb();
+
+ memset(&icount, 0, sizeof(struct serial_icounter_struct));
+
icount.cts = cnow.cts;
icount.dsr = cnow.dsr;
icount.rng = cnow.rng;