From 7d97bb1b9c22d1fda0a60a8d57ded9cc51d161d6 Mon Sep 17 00:00:00 2001
From: John Keeping <jkeeping@inmusicbrands.com>
Date: Thu, 30 Jan 2025 19:50:34 +0000
Subject: [PATCH] usb: gadget: f_midi: fix MIDI Streaming descriptor lengths
commit da1668997052ed1cb00322e1f3b63702615c9429 upstream.
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 <stable@kernel.org>
Fixes: c8933c3f79568 ("USB: gadget: f_midi: allow a dynamic number of input and output ports")
Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20250130195035.3883857-1-jkeeping@inmusicbrands.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/gadget/function/f_midi.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index fddf539008a99..1d8521103b661 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -999,11 +999,11 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
}
/* configure the endpoint descriptors ... */
- ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
- ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
+ ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
+ ms_out_desc.bNumEmbMIDIJack = midi->out_ports;
- ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
- ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
+ ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
+ ms_in_desc.bNumEmbMIDIJack = midi->in_ports;
/* ... and add them to the list */
endpoint_descriptor_index = i;
--
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