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| author | HyeongJun An <sammiee5311@gmail.com> | 2026-09-01 18:04:09 +0900 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2026-09-01 12:36:53 +0200 |
| commit | e4637ce34607f1733a34a57294966d26b263e626 (patch) | |
| tree | 774d3cdc5b6f554bcc27d528c0ade53f215287e7 /sound | |
| parent | 9b110a9dcecc59516c77cb3c0caf1f492f75df2d (diff) | |
| download | linux-e4637ce34607f1733a34a57294966d26b263e626.tar.gz linux-e4637ce34607f1733a34a57294966d26b263e626.zip | |
ALSA: usb-audio: fix OOB write in snd_usbmidi_us122l_output()
The snd_usbmidi_us122l_output() picks a count of 2 on anything slower
than high speed and never relates it to ep->max_transfer. The URB
buffer holds exactly max_transfer bytes, so a device declaring a one
byte bulk endpoint takes two bytes from snd_rawmidi_transmit(), and the
memset that pads the rest computes 1 - 2 in int and wraps to SIZE_MAX.
Only 0x800e and 0x800f are pinned to nine bytes. The US-122MKII at
0x0644:0x8021 falls to the default and takes usb_maxpacket(), which the
USB core only clamps downward.
The akai and novation output ops in this file were given the same guard
recently. Do the same here.
Fixes: 030a07e44129 ("ALSA: Add USB US122L driver")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-5
Signed-off-by: HyeongJun An <sammiee5311@gmail.com>
Link: https://patch.msgid.link/20260901090409.1478573-1-sammiee5311@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/usb/midi.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index 8a9bc37f0b6e..7e5b1b13360f 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -971,6 +971,8 @@ static void snd_usbmidi_us122l_output(struct snd_usb_midi_out_endpoint *ep, default: count = 2; } + if (ep->max_transfer < count) + return; count = snd_rawmidi_transmit(ep->ports[0].substream, urb->transfer_buffer, count); |