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SubjectRe: [PATCH 4.4 02/74] usbip: prevent vhci_hcd driver from leaking a socket pointer address
On Mon, Jan 29, 2018 at 01:56:07PM +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Shuah Khan <shuahkh@osg.samsung.com>
>
> commit 2f2d0088eb93db5c649d2a5e34a3800a8a935fc5 upstream.
>
> When a client has a USB device attached over IP, the vhci_hcd driver is
> locally leaking a socket pointer address via the
>
> /sys/devices/platform/vhci_hcd/status file (world-readable) and in debug
> output when "usbip --debug port" is run.
>
> Fix it to not leak. The socket pointer address is not used at the moment
> and it was made visible as a convenient way to find IP address from socket
> pointer address by looking up /proc/net/{tcp,tcp6}.
>
> As this opens a security hole, the fix replaces socket pointer address with
> sockfd.
>
> Reported-by: Secunia Research <vuln@secunia.com>
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
>
> ---
> drivers/usb/usbip/usbip_common.h | 1 +
> drivers/usb/usbip/vhci_sysfs.c | 25 +++++++++++++++----------
> tools/usb/usbip/libsrc/vhci_driver.c | 8 ++++----
> 3 files changed, 20 insertions(+), 14 deletions(-)
>
> --- a/drivers/usb/usbip/usbip_common.h
> +++ b/drivers/usb/usbip/usbip_common.h
> @@ -261,6 +261,7 @@ struct usbip_device {
> /* lock for status */
> spinlock_t lock;
>
> + int sockfd;
> struct socket *tcp_socket;
>
> struct task_struct *tcp_rx;
> --- a/drivers/usb/usbip/vhci_sysfs.c
> +++ b/drivers/usb/usbip/vhci_sysfs.c
> @@ -39,16 +39,20 @@ static ssize_t status_show(struct device
>
> /*
> * output example:
> - * prt sta spd dev socket local_busid
> - * 000 004 000 000 c5a7bb80 1-2.3
> - * 001 004 000 000 d8cee980 2-3.4
> + * port sta spd dev sockfd local_busid
> + * 0000 004 000 00000000 000003 1-2.3
> + * 0001 004 000 00000000 000004 2-3.4
> *
> - * IP address can be retrieved from a socket pointer address by looking
> - * up /proc/net/{tcp,tcp6}. Also, a userland program may remember a
> - * port number and its peer IP address.
> + * Output includes socket fd instead of socket pointer address to
> + * avoid leaking kernel memory address in:
> + * /sys/devices/platform/vhci_hcd.0/status and in debug output.
> + * The socket pointer address is not used at the moment and it was
> + * made visible as a convenient way to find IP address from socket
> + * pointer address by looking up /proc/net/{tcp,tcp6}. As this opens
> + * a security hole, the change is made to use sockfd instead.
> */
> out += sprintf(out,
> - "prt sta spd bus dev socket local_busid\n");
> + "prt sta spd bus dev sockfd local_busid\n");
>
> for (i = 0; i < VHCI_NPORTS; i++) {
> struct vhci_device *vdev = port_to_vdev(i);
> @@ -60,11 +64,11 @@ static ssize_t status_show(struct device
> out += sprintf(out, "%03u %08x ",
> vdev->speed, vdev->devid);
> out += sprintf(out, "%16p ", vdev->ud.tcp_socket);
> + out += sprintf(out, "%06u", vdev->ud.sockfd);
> out += sprintf(out, "%s", dev_name(&vdev->udev->dev));

This backport is wrong; it's still printing the pointer...

Eric

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