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SubjectRe: [PATCH 4.4 02/74] usbip: prevent vhci_hcd driver from leaking a socket pointer address
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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

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