Re: [Linux-stable-mirror] [PATCH 4.4 02/74] usbip: prevent vhci_hcd driver from leaking a socket pointer address

On 02/03/2018 01:30 AM, Eric Biggers wrote:

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

Eric,

Yes I have a patch ready to send to fix this problem. My bad.

thanks, -- Shuah