linux-kernel - [PATCH] ALSA: bcd2000: Fix a UAF bug on the error path of probing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220715010515.2087925-1-zheyuma97@gmail.com>
Date:   Fri, 15 Jul 2022 09:05:15 +0800
From:   Zheyu Ma <zheyuma97@...il.com>
To:     perex@...ex.cz, tiwai@...e.com
Cc:     alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        Zheyu Ma <zheyuma97@...il.com>
Subject: [PATCH] ALSA: bcd2000: Fix a UAF bug on the error path of probing

When the driver fails in snd_card_register() at probe time, it will free
the 'bcd2k->midi_out_urb' before killing it, which may cause a UAF bug.

The following log can reveal it:

[   50.727020] BUG: KASAN: use-after-free in bcd2000_input_complete+0x1f1/0x2e0 [snd_bcd2000]
[   50.727623] Read of size 8 at addr ffff88810fab0e88 by task swapper/4/0
[   50.729530] Call Trace:
[   50.732899]  bcd2000_input_complete+0x1f1/0x2e0 [snd_bcd2000]

Fix this by adding usb_kill_urb() before usb_free_urb().

Fixes: b47a22290d58 ("ALSA: MIDI driver for Behringer BCD2000 USB device")
Signed-off-by: Zheyu Ma <zheyuma97@...il.com>
---
 sound/usb/bcd2000/bcd2000.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/usb/bcd2000/bcd2000.c b/sound/usb/bcd2000/bcd2000.c
index cd4a0bc6d278..7aec0a95c609 100644
--- a/sound/usb/bcd2000/bcd2000.c
+++ b/sound/usb/bcd2000/bcd2000.c
@@ -348,7 +348,8 @@ static int bcd2000_init_midi(struct bcd2000 *bcd2k)
 static void bcd2000_free_usb_related_resources(struct bcd2000 *bcd2k,
 						struct usb_interface *interface)
 {
-	/* usb_kill_urb not necessary, urb is aborted automatically */
+	usb_kill_urb(bcd2k->midi_out_urb);
+	usb_kill_urb(bcd2k->midi_in_urb);
 
 	usb_free_urb(bcd2k->midi_out_urb);
 	usb_free_urb(bcd2k->midi_in_urb);
-- 
2.25.1