From: Takashi Iwai <ti...@suse.de> commit c06ccf3ebb7503706ea49fd248e709287ef385a3 upstream.
The calculation of in_cables and out_cables bitmaps are done with the bit shift by the value from the descriptor, which is an arbitrary value, and can lead to UBSAN shift-out-of-bounds warnings. Fix it by filtering the bad descriptor values with the check of the upper bound 0x10 (the cable bitmaps are 16 bits). Reported-by: syzbot+92e45ae45543f89e8...@syzkaller.appspotmail.com Cc: <sta...@vger.kernel.org> Link: https://lore.kernel.org/r/20201223174557.10249-1-ti...@suse.de Signed-off-by: Takashi Iwai <ti...@suse.de> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- sound/usb/midi.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1889,6 +1889,8 @@ static int snd_usbmidi_get_ms_info(struc ms_ep = find_usb_ms_endpoint_descriptor(hostep); if (!ms_ep) continue; + if (ms_ep->bNumEmbMIDIJack > 0x10) + continue; if (usb_endpoint_dir_out(ep)) { if (endpoints[epidx].out_ep) { if (++epidx >= MIDI_MAX_ENDPOINTS) { @@ -2141,6 +2143,8 @@ static int snd_usbmidi_detect_roland(str cs_desc[1] == USB_DT_CS_INTERFACE && cs_desc[2] == 0xf1 && cs_desc[3] == 0x02) { + if (cs_desc[4] > 0x10 || cs_desc[5] > 0x10) + continue; endpoint->in_cables = (1 << cs_desc[4]) - 1; endpoint->out_cables = (1 << cs_desc[5]) - 1; return snd_usbmidi_detect_endpoints(umidi, endpoint, 1);
