[ 3.8.y.z extended stable ] Patch "USB: mos7720: fix broken control requests" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    USB: mos7720: fix broken control requests

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.8.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 1e4538ec7cda09173d51504e736e7b5c3ea5549c Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold at gmail.com>
Date: Tue, 13 Aug 2013 13:27:34 +0200
Subject: USB: mos7720: fix broken control requests

commit ef6c8c1d733e244f0499035be0dabe1f4ed98c6f upstream.

The parallel-port code of the drivers used a stack allocated
control-request buffer for asynchronous (and possibly deferred) control
requests. This not only violates the no-DMA-from-stack requirement but
could also lead to corrupt control requests being submitted.

Signed-off-by: Johan Hovold <jhovold at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/serial/mos7720.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index d166d3a..397e028 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -91,6 +91,7 @@ struct urbtracker {
 	struct list_head        urblist_entry;
 	struct kref             ref_count;
 	struct urb              *urb;
+	struct usb_ctrlrequest	*setup;
 };

 enum mos7715_pp_modes {
@@ -272,6 +273,7 @@ static void destroy_urbtracker(struct kref *kref)
 	struct mos7715_parport *mos_parport = urbtrack->mos_parport;

 	usb_free_urb(urbtrack->urb);
+	kfree(urbtrack->setup);
 	kfree(urbtrack);
 	kref_put(&mos_parport->ref_count, destroy_mos_parport);
 }
@@ -356,7 +358,6 @@ static int write_parport_reg_nonblock(struct mos7715_parport *mos_parport,
 	struct urbtracker *urbtrack;
 	int ret_val;
 	unsigned long flags;
-	struct usb_ctrlrequest setup;
 	struct usb_serial *serial = mos_parport->serial;
 	struct usb_device *usbdev = serial->dev;

@@ -374,14 +375,20 @@ static int write_parport_reg_nonblock(struct mos7715_parport *mos_parport,
 		kfree(urbtrack);
 		return -ENOMEM;
 	}
-	setup.bRequestType = (__u8)0x40;
-	setup.bRequest = (__u8)0x0e;
-	setup.wValue = get_reg_value(reg, dummy);
-	setup.wIndex = get_reg_index(reg);
-	setup.wLength = 0;
+	urbtrack->setup = kmalloc(sizeof(*urbtrack->setup), GFP_KERNEL);
+	if (!urbtrack->setup) {
+		usb_free_urb(urbtrack->urb);
+		kfree(urbtrack);
+		return -ENOMEM;
+	}
+	urbtrack->setup->bRequestType = (__u8)0x40;
+	urbtrack->setup->bRequest = (__u8)0x0e;
+	urbtrack->setup->wValue = get_reg_value(reg, dummy);
+	urbtrack->setup->wIndex = get_reg_index(reg);
+	urbtrack->setup->wLength = 0;
 	usb_fill_control_urb(urbtrack->urb, usbdev,
 			     usb_sndctrlpipe(usbdev, 0),
-			     (unsigned char *)&setup,
+			     (unsigned char *)urbtrack->setup,
 			     NULL, 0, async_complete, urbtrack);
 	kref_init(&urbtrack->ref_count);
 	INIT_LIST_HEAD(&urbtrack->urblist_entry);
--
1.8.1.2