Re: [PATCH v2] usb: gadget: f_midi: fix MIDI Streaming descriptor lengths

[Takashi Iwai]

On Thu, 30 Jan 2025 20:50:34 +0100,
John Keeping wrote:
> 
> While the MIDI jacks are configured correctly, and the MIDIStreaming
> endpoint descriptors are filled with the correct information,
> bNumEmbMIDIJack and bLength are set incorrectly in these descriptors.
> 
> This does not matter when the numbers of in and out ports are equal, but
> when they differ the host will receive broken descriptors with
> uninitialized stack memory leaking into the descriptor for whichever
> value is smaller.
> 
> The precise meaning of "in" and "out" in the port counts is not clearly
> defined and can be confusing.  But elsewhere the driver consistently
> uses this to match the USB meaning of IN and OUT viewed from the host,
> so that "in" ports send data to the host and "out" ports receive data
> from it.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports")
> Signed-off-by: John Keeping <jkeeping@xxxxxxxxxxxxxxxxx>

Reviewed-by: Takashi Iwai <tiwai@xxxxxxx>


Thanks!

Takashi