patch "USB: serial: mos7720: fix use-after-free on probe errors" added to usb-linus

patch "USB: serial: mos7720: fix use-after-free on probe errors" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    USB: serial: mos7720: fix use-after-free on probe errors

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 91a1ff4d53c5184d383d0baeeaeab6f9736f2ff3 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Tue, 3 Jan 2017 16:39:51 +0100
Subject: USB: serial: mos7720: fix use-after-free on probe errors

The interrupt URB was submitted on probe but never stopped on probe
errors. This can lead to use-after-free issues in the completion
handler when accessing the freed usb-serial struct:

Unable to handle kernel paging request at virtual address 6b6b6be7
...
[<bf052e70>] (mos7715_interrupt_callback [mos7720]) from [<c052a894>] (__usb_hcd_giveback_urb+0x80/0x140)
[<c052a894>] (__usb_hcd_giveback_urb) from [<c052a9a4>] (usb_hcd_giveback_urb+0x50/0x138)
[<c052a9a4>] (usb_hcd_giveback_urb) from [<c0550684>] (musb_giveback+0xc8/0x1cc)

Fixes: b69578df7e98 ("USB: usbserial: mos7720: add support for parallel
port on moschip 7715")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/mos7720.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 3220d0bc767b..9170ae856b34 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -1962,8 +1962,10 @@ static int mos7720_startup(struct usb_serial *serial)
 #ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
 	if (product == MOSCHIP_DEVICE_ID_7715) {
 		ret_val = mos7715_parport_init(serial);
-		if (ret_val < 0)
+		if (ret_val < 0) {
+			usb_kill_urb(serial->port[0]->interrupt_in_urb);
 			return ret_val;
+		}
 	}
 #endif
 	/* LSR For Port 1 */
@@ -1975,6 +1977,8 @@ static int mos7720_startup(struct usb_serial *serial)
 
 static void mos7720_release(struct usb_serial *serial)
 {
+	usb_kill_urb(serial->port[0]->interrupt_in_urb);
+
 #ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
 	/* close the parallel port */
 
-- 
2.11.0