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| author | Takashi Iwai <tiwai@suse.de> | 2026-08-08 17:20:06 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2026-08-08 17:51:43 +0200 |
| commit | f8a80cfb68613fb7e6452b66447dbc63f435d140 (patch) | |
| tree | b8e6a8bae5a4161028ecfff817ead1c01291bdba | |
| parent | a8934c2c6dfd72901cf3cc0de28e85eb902a61a4 (diff) | |
| download | linux-f8a80cfb68613fb7e6452b66447dbc63f435d140.tar.gz linux-f8a80cfb68613fb7e6452b66447dbc63f435d140.zip | |
ALSA: usb: Fix UAF at delayed release of MIDI2 EPs
The recent fix for UAF in ump_to_endpoint() caused another UAF because
it tries to dereference the UMP endpoint object, but this might be
executed at a delayed context where the endpoint has been already
released.
Add private_free to clear the associated data for avoiding the further
dereference for delayed releases.
Fixes: 4a05b2d1b464 ("ALSA: usb-audio: fix use-after-free in ump_to_endpoint()")
Reported-by: syzbot+565b1138cfbe549d4422@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=565b1138cfbe549d4422
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20260808152009.1947835-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
| -rw-r--r-- | sound/usb/midi2.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/sound/usb/midi2.c b/sound/usb/midi2.c index 83980fb83ac8..1dc78f536ef9 100644 --- a/sound/usb/midi2.c +++ b/sound/usb/midi2.c @@ -677,6 +677,14 @@ static int parse_midi_2_0_endpoints(struct snd_usb_midi2_interface *umidi) return 0; } +static void free_ump_private_data(struct snd_ump_endpoint *ump) +{ + struct snd_usb_midi2_ump *rmidi = ump->private_data; + + if (rmidi) + rmidi->ump = NULL; +} + static void free_all_midi2_umps(struct snd_usb_midi2_interface *umidi) { struct snd_usb_midi2_ump *rmidi; @@ -727,6 +735,7 @@ static int create_midi2_ump(struct snd_usb_midi2_interface *umidi, ump->private_data = rmidi; ump->ops = &snd_usb_midi_v2_ump_ops; + ump->private_free = free_ump_private_data; rmidi->eps[STR_IN] = ep_in; rmidi->eps[STR_OUT] = ep_out; |