• Lars-Peter Clausen's avatar
    gpio: GPIO_GET_LINEHANDLE_IOCTL: Reject invalid line flags · e3e847c7
    Lars-Peter Clausen authored
    The GPIO_GET_LINEHANDLE_IOCTL currently ignores unknown or undefined
    linehandle flags. From a backwards and forwards compatibility viewpoint it
    is highly desirable to reject unknown flags though.
    
    On one hand an application that is using newer flags and is running on
    an older kernel has no way to detect if the new flags were handled
    correctly if they are silently discarded.
    
    On the other hand an application that (accidentally) passes undefined flags
    will run fine on an older kernel, but may break on a newer kernel when
    these flags get defined.
    
    Ensure that requests that have undefined flags set are rejected with an
    error, rather than silently discarding the undefined flags.
    
    Cc: stable@vger.kernel.org
    Fixes: d7c51b47 ("gpio: userspace ABI for reading/writing GPIO lines")
    Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
    Signed-off-by: Linus Walleij's avatarLinus Walleij <linus.walleij@linaro.org>
    e3e847c7
gpiolib.c 94.8 KB