snd_usbmidi_get_ms_info() may access beyond the border when a
malformed descriptor is passed. This patch adds the sanity checks of
the given MS endpoint descriptors, and skips invalid ones.
Reported-by: syzbot+6bb23a5d5548b93c94aa@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
sound/usb/midi.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index a10ac75969a8..649eb8d1ab7d 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -1956,8 +1956,12 @@ 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->bLength <= sizeof(*ms_ep))
+ continue;
if (ms_ep->bNumEmbMIDIJack > 0x10)
continue;
+ if (ms_ep->bLength < sizeof(*ms_ep) + ms_ep->bNumEmbMIDIJack)
+ continue;
if (usb_endpoint_dir_out(ep)) {
if (endpoints[epidx].out_ep) {
if (++epidx >= MIDI_MAX_ENDPOINTS) {
--
2.26.2
