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

USB: devio: Prevent integer overflow in proc_do_submiturb()

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: usb-devio-prevent-integer-overflow-in-proc_do_submiturb.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 57999d1107c1e60c2ca7088f2ac0f819e2f554b3 Mon Sep 17 00:00:00 2001

From: Dan Carpenter dan.carpenter@oracle.com Date: Fri, 22 Sep 2017 23:43:25 +0300 Subject: USB: devio: Prevent integer overflow in proc_do_submiturb()

From: Dan Carpenter dan.carpenter@oracle.com

commit 57999d1107c1e60c2ca7088f2ac0f819e2f554b3 upstream.

There used to be an integer overflow check in proc_do_submiturb() but we removed it. It turns out that it's still required. The uurb->buffer_length variable is a signed integer and it's controlled by the user. It can lead to an integer overflow when we do:

num_sgs = DIV_ROUND_UP(uurb->buffer_length, USB_SG_SIZE);

If we strip away the macro then that line looks like this:

num_sgs = (uurb->buffer_length + USB_SG_SIZE - 1) / USB_SG_SIZE; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ It's the first addition which can overflow.

Fixes: 1129d270cbfb ("USB: Increase usbfs transfer limit") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Acked-by: Alan Stern stern@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/usb/core/devio.c | 5 +++++ 1 file changed, 5 insertions(+)

--- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -118,6 +118,9 @@ module_param(usbfs_memory_mb, uint, 0644 MODULE_PARM_DESC(usbfs_memory_mb, "maximum MB allowed for usbfs buffers (0 = no limit)");

+/* Hard limit, necessary to avoid arithmetic overflow */ +#define USBFS_XFER_MAX (UINT_MAX / 2 - 1000000) + static atomic64_t usbfs_memory_usage; /* Total memory currently allocated */

/* Check whether it's okay to allocate more memory for a transfer */ @@ -1298,6 +1301,8 @@ static int proc_do_submiturb(struct usb_ USBDEVFS_URB_ZERO_PACKET | USBDEVFS_URB_NO_INTERRUPT)) return -EINVAL; + if ((unsigned int)uurb->buffer_length >= USBFS_XFER_MAX) + return -EINVAL; if (uurb->buffer_length > 0 && !uurb->buffer) return -EINVAL; if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL &&

Patches currently in stable-queue which might be from dan.carpenter@oracle.com are

queue-4.4/usb-devio-prevent-integer-overflow-in-proc_do_submiturb.patch