From: Takashi Iwai Date: Wed, 23 Dec 2020 17:45:57 +0000 (+0100) Subject: ALSA: usb-audio: Fix UBSAN warnings for MIDI jacks X-Git-Tag: v4.4.251~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=34cf6eedfa7ec0f2f6d4d1bcc9bcdcdb31ab7c9b;p=thirdparty%2Fkernel%2Fstable.git ALSA: usb-audio: Fix UBSAN warnings for MIDI jacks 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+92e45ae45543f89e8c88@syzkaller.appspotmail.com Cc: Link: https://lore.kernel.org/r/20201223174557.10249-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- diff --git a/sound/usb/midi.c b/sound/usb/midi.c index 934540042bc2e..df6fde6fd2b6b 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1865,6 +1865,8 @@ static int snd_usbmidi_get_ms_info(struct snd_usb_midi *umidi, 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) { @@ -2117,6 +2119,8 @@ static int snd_usbmidi_detect_roland(struct snd_usb_midi *umidi, 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);