From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from r3-23.sinamail.sina.com.cn (r3-23.sinamail.sina.com.cn [202.108.3.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB7FE49DB88 for ; Thu, 3 Sep 2026 11:57:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.108.3.23 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788436637; cv=none; b=u+vaArhyB55XrkfyJhXsouexRSrXwig68QjMG1CTVfnVir1+z5jkMmGDMw2deKwUCQUvp5zFTNH5gKKxJT2BKpaZ8ORqz9APbCtNPTVGey7nCgJZEg1eGLDb7JJgNc3X2zo0O82fi3pibuq75jz38ErEzNDw/F/oLrp6Xc3Z9pk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788436637; c=relaxed/simple; bh=UjZb9Pn1U3m39gxKvKnbLa3QipMLxknqpp89+n6OH30=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mHs5RKepEf/y0DBJBXM6cXuu95CXjC428fJPDXAgspZEI0XGRmc2S2ycQsGsF7AUavDPmMcz0OnuVZ02va+aJaW5+qUpUqqfz4OEVmtECQxFXbfqZ3wsz9y2+5QdVtEg0dzLX2bNZSDcMXyeUzEYlOn3epMJC/Bcb4Ut7AONTag= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=cYavcNzq; arc=none smtp.client-ip=202.108.3.23 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="cYavcNzq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1788436632; bh=OgTS4SBqntVJukFiLqrMD1eJ5BKRre7ShPJPymPauR4=; h=From:Subject:Date:Message-ID; b=cYavcNzqWFIqJ1tjFufV+/DIIxhu1wtQOpZUR8bJlfCBBW+gpL1WDIaO5pV3t3vwl eO/aNh73tEs19s8WdJbFhS8x/J8JJQ6DVjGazOpdKHkgM+vtn4dl1wxIhchqBQzJjE 3iP3XrYpsxg4W1O1pzdMfHX2j2yY13PGtAr3+AGc= X-SMAIL-HELO: lxu-ped-host.. Received: from unknown (HELO lxu-ped-host..)([111.198.231.89]) by sina.com (10.54.253.31) with ESMTP id 6A99608400007334; Thu, 3 Sep 2026 19:57:00 +0800 (CST) X-Sender: eadavis@sina.com X-Auth-ID: eadavis@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=eadavis@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=eadavis@sina.com X-SMAIL-MID: 8967206815970 X-SMAIL-UIID: 0B28638A9924401DA4803ECBDE1D26C7-20260903-195700-1 From: Edward Adam Davis To: tiwai@suse.de Cc: daniel@caiaq.org, eadavis@sina.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org, linux-usb@vger.kernel.org, perex@perex.cz, syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com, tiwai@suse.com, zonque@gmail.com Subject: [PATCH v3] ALSA: caiaq: Decoupling ep1_in_urb in caiaq dev Date: Thu, 3 Sep 2026 19:56:52 +0800 Message-ID: <20260903115652.550250-1-eadavis@sina.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <87ld9i8xe6.wl-tiwai@suse.de> References: <87ld9i8xe6.wl-tiwai@suse.de> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The epq_in_urb object belonging to the caiaq device is coupled within the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL) executes successfully, epq_in_urb is successfully added to the urbp_list queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD layer driver for the caiaq USB device). When init_card() calls snd_usb_caiaq_send_command() which subsequently fails due to a timeout, and proceeds to call snd_card_free() to release the card, the embedded ep1_in_urb object is also freed. When the dummy HCD driver detects that the URB has been unlinked, it returns the URB (by usb_hcd_giveback_urb()), which triggers [1]. Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch to using a pointer instead. Separately allocate and manage the memory for ep1_in_urb to prevent the release of the snd_card memory object from interfering with it. midi_out_urb has the same issue as ep1_in_urb and is handled in the same way. [1] BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96 Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29 Call Trace: usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96 dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019 __run_hrtimer kernel/time/hrtimer.c:2067 [inline] __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124 hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141 Allocated by task 36: snd_card_new+0x7b/0x110 sound/core/init.c:184 create_card sound/usb/caiaq/device.c:429 [inline] snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544 Freed by task 36: snd_card_free_when_closed sound/core/init.c:630 [inline] snd_card_free+0x138/0x1d0 sound/core/init.c:662 snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553 Fixes: 523f1dce3743 ("[ALSA] Add Native Instrument usb audio device support") Reported-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=832ce9fa3face1b7d44d Tested-by: syzbot+832ce9fa3face1b7d44d@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis --- v1 -> v2: same dealwith midi_out_urb and add missing check v2 -> v3: set ep1_in_urb to NULL after midi_out_urb allow failed remove err message when alloc failed sound/usb/caiaq/device.c | 38 ++++++++++++++++++++++++++------------ sound/usb/caiaq/device.h | 4 ++-- sound/usb/caiaq/midi.c | 6 +++--- 3 files changed, 31 insertions(+), 17 deletions(-) diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c index a16e59248480..ff761978a1cf 100644 --- a/sound/usb/caiaq/device.c +++ b/sound/usb/caiaq/device.c @@ -192,8 +192,8 @@ static void usb_ep1_command_reply_dispatch (struct urb* urb) break; } - cdev->ep1_in_urb.actual_length = 0; - ret = usb_submit_urb(&cdev->ep1_in_urb, GFP_ATOMIC); + cdev->ep1_in_urb->actual_length = 0; + ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC); if (ret < 0) dev_err(dev, "unable to submit urb. OOM!?\n"); } @@ -408,6 +408,10 @@ static void card_free(struct snd_card *card) #endif snd_usb_caiaq_audio_free(cdev); usb_put_dev(cdev->chip.dev); + usb_free_urb(cdev->ep1_in_urb); + cdev->ep1_in_urb = NULL; + usb_free_urb(cdev->midi_out_urb); + cdev->midi_out_urb = NULL; } static int create_card(struct usb_device *usb_dev, @@ -457,22 +461,32 @@ static int init_card(struct snd_usb_caiaqdev *cdev) return -EIO; } - usb_init_urb(&cdev->ep1_in_urb); - usb_init_urb(&cdev->midi_out_urb); + cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL); + if (!cdev->ep1_in_urb) + return -ENOMEM; - usb_fill_bulk_urb(&cdev->ep1_in_urb, usb_dev, + cdev->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL); + if (!cdev->midi_out_urb) { + usb_free_urb(cdev->ep1_in_urb); + cdev->ep1_in_urb = NULL; + return -ENOMEM; + } + usb_init_urb(cdev->ep1_in_urb); + usb_init_urb(cdev->midi_out_urb); + + usb_fill_bulk_urb(cdev->ep1_in_urb, usb_dev, usb_rcvbulkpipe(usb_dev, 0x1), cdev->ep1_in_buf, EP1_BUFSIZE, usb_ep1_command_reply_dispatch, cdev); - usb_fill_bulk_urb(&cdev->midi_out_urb, usb_dev, + usb_fill_bulk_urb(cdev->midi_out_urb, usb_dev, usb_sndbulkpipe(usb_dev, 0x1), cdev->midi_out_buf, EP1_BUFSIZE, snd_usb_caiaq_midi_output_done, cdev); /* sanity checks of EPs before actually submitting */ - if (usb_urb_ep_type_check(&cdev->ep1_in_urb) || - usb_urb_ep_type_check(&cdev->midi_out_urb)) { + if (usb_urb_ep_type_check(cdev->ep1_in_urb) || + usb_urb_ep_type_check(cdev->midi_out_urb)) { dev_err(dev, "invalid EPs\n"); return -EINVAL; } @@ -480,7 +494,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev) init_waitqueue_head(&cdev->ep1_wait_queue); init_waitqueue_head(&cdev->prepare_wait_queue); - if (usb_submit_urb(&cdev->ep1_in_urb, GFP_KERNEL) != 0) + if (usb_submit_urb(cdev->ep1_in_urb, GFP_KERNEL) != 0) return -EIO; err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL, 0); @@ -530,7 +544,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev) return 0; err_kill_urb: - usb_kill_urb(&cdev->ep1_in_urb); + usb_kill_urb(cdev->ep1_in_urb); return err; } @@ -576,8 +590,8 @@ static void snd_disconnect(struct usb_interface *intf) #endif snd_usb_caiaq_audio_disconnect(cdev); - usb_kill_urb(&cdev->ep1_in_urb); - usb_kill_urb(&cdev->midi_out_urb); + usb_kill_urb(cdev->ep1_in_urb); + usb_kill_urb(cdev->midi_out_urb); snd_card_free_when_closed(card); } diff --git a/sound/usb/caiaq/device.h b/sound/usb/caiaq/device.h index 743eb0387b5f..1c6f34693fa8 100644 --- a/sound/usb/caiaq/device.h +++ b/sound/usb/caiaq/device.h @@ -60,8 +60,8 @@ struct snd_usb_caiaq_cb_info; struct snd_usb_caiaqdev { struct snd_usb_audio chip; - struct urb ep1_in_urb; - struct urb midi_out_urb; + struct urb *ep1_in_urb; + struct urb *midi_out_urb; struct urb **data_urbs_in; struct urb **data_urbs_out; struct snd_usb_caiaq_cb_info *data_cb_info; diff --git a/sound/usb/caiaq/midi.c b/sound/usb/caiaq/midi.c index c656d0162432..18529484c8dc 100644 --- a/sound/usb/caiaq/midi.c +++ b/sound/usb/caiaq/midi.c @@ -43,7 +43,7 @@ static int snd_usb_caiaq_midi_output_close(struct snd_rawmidi_substream *substre { struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data; if (cdev->midi_out_active) { - usb_kill_urb(&cdev->midi_out_urb); + usb_kill_urb(cdev->midi_out_urb); cdev->midi_out_active = 0; } return 0; @@ -64,9 +64,9 @@ static void snd_usb_caiaq_midi_send(struct snd_usb_caiaqdev *cdev, return; cdev->midi_out_buf[2] = len; - cdev->midi_out_urb.transfer_buffer_length = len+3; + cdev->midi_out_urb->transfer_buffer_length = len+3; - ret = usb_submit_urb(&cdev->midi_out_urb, GFP_ATOMIC); + ret = usb_submit_urb(cdev->midi_out_urb, GFP_ATOMIC); if (ret < 0) dev_err(dev, "snd_usb_caiaq_midi_send(%p): usb_submit_urb() failed," -- 2.43.0