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[3.5.y.z,extended,stable] Patch "USB: io_ti: fix use-after-free in TIOCMIWAIT" has been added to staging queue

Message ID 1364234582-9781-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques March 25, 2013, 6:03 p.m. UTC
This is a note to let you know that I have just added a patch titled

    USB: io_ti: fix use-after-free in TIOCMIWAIT

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From a04251c70dd0ae7f898184c93a165835b730921c Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@gmail.com>
Date: Tue, 19 Mar 2013 09:21:17 +0100
Subject: [PATCH] USB: io_ti: fix use-after-free in TIOCMIWAIT

commit 7b2459690584f239650a365f3411ba2ec1c6d1e0 upstream.

Use the port wait queue and make sure to check the serial disconnected
flag before accessing private port data after waking up.

This is is needed as the private port data (including the wait queue
itself) can be gone when waking up after a disconnect.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Luis Henriques <luis.henriques@canonical.com>
---
 drivers/usb/serial/io_ti.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--
1.8.1.2
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Patch

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index d81630d..b08bb9c 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -91,9 +91,6 @@  struct edgeport_port {
 	int close_pending;
 	int lsr_event;
 	struct async_icount	icount;
-	wait_queue_head_t	delta_msr_wait;	/* for handling sleeping while
-						   waiting for msr change to
-						   happen */
 	struct edgeport_serial	*edge_serial;
 	struct usb_serial_port	*port;
 	__u8 bUartMode;		/* Port type, 0: RS232, etc. */
@@ -1542,7 +1539,7 @@  static void handle_new_msr(struct edgeport_port *edge_port, __u8 msr)
 			icount->dcd++;
 		if (msr & EDGEPORT_MSR_DELTA_RI)
 			icount->rng++;
-		wake_up_interruptible(&edge_port->delta_msr_wait);
+		wake_up_interruptible(&edge_port->port->delta_msr_wait);
 	}

 	/* Save the new modem status */
@@ -1860,7 +1857,6 @@  static int edge_open(struct tty_struct *tty, struct usb_serial_port *port)
 	dev = port->serial->dev;

 	memset(&(edge_port->icount), 0x00, sizeof(edge_port->icount));
-	init_waitqueue_head(&edge_port->delta_msr_wait);

 	/* turn off loopback */
 	status = ti_do_config(edge_port, UMPC_SET_CLR_LOOPBACK, 0);
@@ -2552,10 +2548,14 @@  static int edge_ioctl(struct tty_struct *tty,
 		dbg("%s - (%d) TIOCMIWAIT", __func__, port->number);
 		cprev = edge_port->icount;
 		while (1) {
-			interruptible_sleep_on(&edge_port->delta_msr_wait);
+			interruptible_sleep_on(&port->delta_msr_wait);
 			/* see if a signal did it */
 			if (signal_pending(current))
 				return -ERESTARTSYS;
+
+			if (port->serial->disconnected)
+				return -EIO;
+
 			cnow = edge_port->icount;
 			if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
 			    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)