From nobody Sun Feb 8 20:24:29 2026 Received: from mx0b-0064b401.pphosted.com (mx0b-0064b401.pphosted.com [205.220.178.238]) (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 A4B231ACED9; Mon, 14 Apr 2025 07:11:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.178.238 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744614704; cv=none; b=F43v5LX+6Ayybjq8xbLrNCxTF8VoSHmOsIljHgD7k71PisfbvuUu5L9zDlTBHxTayZNeeSzN4cmda7XA1i23GpjST23JyJTureakn4gg99IsY0L/h/uaK8B8iwlmnrimCfaG1g11pYn4o5D2nZnqnulUZxn/ztzcbVvlJhzw2qs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744614704; c=relaxed/simple; bh=a3z2gobzf/ht5/7LLqmStK8wn2Ktd7QyL6AJSjQ4fRc=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uZN9RwtfHlbxGJQxq7m3/zq794SgilTAK+GrMvFDx16p0Ticy+c775cai0IxHzqAoQHAbK1oXn8oMuo+A7kU1VcMBhgcoJRjV5Lr+F/JuhPQwDxSvrk2Q1OMsBC2ePu+4D+T+eu2Iik1FYx2kHg7WEcra4o5I0VA5ZMvDVPNppE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com; spf=pass smtp.mailfrom=windriver.com; arc=none smtp.client-ip=205.220.178.238 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=windriver.com Received: from pps.filterd (m0250812.ppops.net [127.0.0.1]) by mx0a-0064b401.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 53E6eWLu005022; Mon, 14 Apr 2025 07:11:29 GMT Received: from ala-exchng01.corp.ad.wrs.com (ala-exchng01.wrs.com [147.11.82.252]) by mx0a-0064b401.pphosted.com (PPS) with ESMTPS id 45yf58hp32-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Mon, 14 Apr 2025 07:11:29 +0000 (GMT) Received: from ala-exchng01.corp.ad.wrs.com (147.11.82.252) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.43; Mon, 14 Apr 2025 00:11:28 -0700 Received: from pek-lpd-ccm6.wrs.com (147.11.136.210) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server id 15.1.2507.43 via Frontend Transport; Mon, 14 Apr 2025 00:11:24 -0700 From: Lizhi Xu To: CC: , , , , , , , , , , , , , , , Subject: [PATCH V2] software node: Prevent link creation failure from causing kobj reference count imbalance Date: Mon, 14 Apr 2025 15:11:23 +0800 Message-ID: <20250414071123.1228331-1-lizhi.xu@windriver.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Authority-Analysis: v=2.4 cv=UPPdHDfy c=1 sm=1 tr=0 ts=67fcb521 cx=c_pps a=/ZJR302f846pc/tyiSlYyQ==:117 a=/ZJR302f846pc/tyiSlYyQ==:17 a=XR8D0OoHHMoA:10 a=edf1wS77AAAA:8 a=hSkVLCK3AAAA:8 a=t7CeM3EgAAAA:8 a=jCU8iyBe7FSsQOJyWVcA:9 a=DcSpbTIhAlouE1Uv7lRv:22 a=cQPPKAXgyycSBL8etih5:22 a=FdTzh2GWekK77mhwV6Dw:22 X-Proofpoint-GUID: JmkLrTrDFaAacdP3HHIuJLTkWap88zL4 X-Proofpoint-ORIG-GUID: JmkLrTrDFaAacdP3HHIuJLTkWap88zL4 X-Sensitive_Customer_Information: Yes X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1095,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-04-14_01,2025-04-10_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=721 spamscore=0 priorityscore=1501 impostorscore=0 suspectscore=0 mlxscore=0 bulkscore=0 lowpriorityscore=0 malwarescore=0 adultscore=0 clxscore=1011 phishscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.21.0-2502280000 definitions=main-2504140050 Content-Type: text/plain; charset="utf-8" syzbot reported a uaf in software_node_notify_remove. [1] When any of the two sysfs_create_link() in software_node_notify() fails, the swnode->kobj reference count will not increase normally, which will cause swnode to be released incorrectly due to the imbalance of kobj refere= nce count when executing software_node_notify_remove(). Increase the reference count of kobj before creating the link to avoid uaf. [1] BUG: KASAN: slab-use-after-free in software_node_notify_remove+0x1bc/0x1c0 = drivers/base/swnode.c:1108 Read of size 1 at addr ffff888033c08908 by task syz-executor105/5844 Freed by task 5844: software_node_notify_remove+0x159/0x1c0 drivers/base/swnode.c:1106 device_platform_notify_remove drivers/base/core.c:2387 [inline] Fixes: 9eb59204d519 ("iommufd/selftest: Add set_dev_pasid in mock iommu") Reported-by: syzbot+2ff22910687ee0dfd48e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D2ff22910687ee0dfd48e Tested-by: syzbot+2ff22910687ee0dfd48e@syzkaller.appspotmail.com Signed-off-by: Lizhi Xu Reviewed-by: Andy Shevchenko Reviewed-by: Sakari Ailus --- V1 -> V2: reduce calltrace drivers/base/swnode.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c index b1726a3515f6..5c78fa6ae772 100644 --- a/drivers/base/swnode.c +++ b/drivers/base/swnode.c @@ -1080,6 +1080,7 @@ void software_node_notify(struct device *dev) if (!swnode) return; =20 + kobject_get(&swnode->kobj); ret =3D sysfs_create_link(&dev->kobj, &swnode->kobj, "software_node"); if (ret) return; @@ -1089,8 +1090,6 @@ void software_node_notify(struct device *dev) sysfs_remove_link(&dev->kobj, "software_node"); return; } - - kobject_get(&swnode->kobj); } =20 void software_node_notify_remove(struct device *dev) --=20 2.43.0