• Nicolas Iooss's avatar
    usb: usbip: vudc: fix left shift overflow · f38d80a5
    Nicolas Iooss authored
    commit 238b7bd9 upstream.
    
    In v_recv_cmd_submit(), urb_p->urb->pipe has the type unsigned int
    (which is 32-bit long on x86_64) but 11<<30 results in a 34-bit integer.
    Therefore the 2 leading bits are truncated and
    
        urb_p->urb->pipe &= ~(11 << 30);
    
    has the same meaning as
    
        urb_p->urb->pipe &= ~(3 << 30);
    
    This second statement seems to be how the code was intended to be
    written, as PIPE_ constants have values between 0 and 3.
    
    The overflow has been detected with a clang warning:
    
        drivers/usb/usbip/vudc_rx.c:145:27: warning: signed shift result
        (0x2C0000000) requires 35 bits to represent, but 'int' only has 32
        bits [-Wshift-overflow]
                urb_p->urb->pipe &= ~(11 << 30);
                                      ~~ ^  ~~
    
    Fixes: 79c02cb1 ("usbip: vudc: Add vudc_rx")
    Signed-off-by: default avatarNicolas Iooss <nicolas.iooss_linux@m4x.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    f38d80a5
vudc_rx.c 5.42 KB