From 310c2d4608d8c1a2baa57db1dfd319c5c40cf4a1 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 1 Sep 2026 16:52:46 +0200 Subject: [PATCH] usb: gadget: midi2: Fix the jack descriptor array sizes The jack in/out descriptor arrays in struct f_midi2_usb_config have the size of MAX_CABLES, which look reasonable -- but it turned out to be incorrect. Namely, the entries for those arrays are added from both inputs and outputs, hence for each loop cycle, it adds two, ended up with as twice as the expected size. This inconsistency may result in potential OOB when a large number of jacks are set up via configfs, although the max number of cables (the loop count) is limited to MAX_CABLES. For addressing it, correct the jack_ins & jack_outs array sizes to twice, MAX_CABLES * 2. Fixes: 856fa444b098 ("usb: gadget: midi2: Dynamically create MIDI 1.0 altset descriptors") Cc: stable Reported-by: syzbot+c35f34092a4bc9855be6@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c35f34092a4bc9855be6 Link: https://lore.kernel.org/20260826134606.127250-1-eadavis@sina.com Cc: Edward Adam Davis Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20260901145512.785142-1-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_midi2.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/f_midi2.c b/drivers/usb/gadget/function/f_midi2.c index 5b8b18281989..d693de427641 100644 --- a/drivers/usb/gadget/function/f_midi2.c +++ b/drivers/usb/gadget/function/f_midi2.c @@ -1633,8 +1633,8 @@ struct f_midi2_usb_config { /* MIDI 1.0 jacks */ unsigned char jack_in, jack_out, jack_id; - struct usb_midi_in_jack_descriptor jack_ins[MAX_CABLES]; - struct usb_midi_out_jack_descriptor_1 jack_outs[MAX_CABLES]; + struct usb_midi_in_jack_descriptor jack_ins[MAX_CABLES * 2]; + struct usb_midi_out_jack_descriptor_1 jack_outs[MAX_CABLES * 2]; }; static int append_config(struct f_midi2_usb_config *config, void *d)