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    Subject[ 46/61] USB: fix gathering of interface associations
    3.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Daniel Mack <zonque@gmail.com>

    commit b3a3dd074f7053ef824ad077e5331b52220ceba1 upstream.

    TEAC's UD-H01 (and probably other devices) have a gap in the interface
    number allocation of their descriptors:

    Configuration Descriptor:
    bLength 9
    bDescriptorType 2
    wTotalLength 220
    bNumInterfaces 3
    [...]
    Interface Descriptor:
    bLength 9
    bDescriptorType 4
    bInterfaceNumber 0
    bAlternateSetting 0
    [...]
    Interface Association:
    bLength 8
    bDescriptorType 11
    bFirstInterface 2
    bInterfaceCount 2
    bFunctionClass 1 Audio
    bFunctionSubClass 0
    bFunctionProtocol 32
    iFunction 4
    Interface Descriptor:
    bLength 9
    bDescriptorType 4
    bInterfaceNumber 2
    bAlternateSetting 0
    [...]

    Once a configuration is selected, usb_set_configuration() walks the
    known interfaces of a given configuration and calls find_iad() on
    each of them to set the interface association pointer the interface
    is included in.

    The problem here is that the loop variable is taken for the interface
    number in the comparison logic that gathers the association. Which is
    fine as long as the descriptors are sane.

    In the case above, however, the logic gets out of sync and the
    interface association fields of all interfaces beyond the interface
    number gap are wrong.

    Fix this by passing the interface's bInterfaceNumber to find_iad()
    instead.

    Signed-off-by: Daniel Mack <zonque@gmail.com>
    Reported-by: bEN <ml_all@circa.be>
    Reported-by: Ivan Perrone <ivanperrone@hotmail.com>
    Tested-by: ivan perrone <ivanperrone@hotmail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/usb/core/message.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    --- a/drivers/usb/core/message.c
    +++ b/drivers/usb/core/message.c
    @@ -1803,7 +1803,6 @@ free_interfaces:
    intfc = cp->intf_cache[i];
    intf->altsetting = intfc->altsetting;
    intf->num_altsetting = intfc->num_altsetting;
    - intf->intf_assoc = find_iad(dev, cp, i);
    kref_get(&intfc->ref);

    alt = usb_altnum_to_altsetting(intf, 0);
    @@ -1816,6 +1815,8 @@ free_interfaces:
    if (!alt)
    alt = &intf->altsetting[0];

    + intf->intf_assoc =
    + find_iad(dev, cp, alt->desc.bInterfaceNumber);
    intf->cur_altsetting = alt;
    usb_enable_interface(dev, intf, true);
    intf->dev.parent = &dev->dev;



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