From nobody Mon Feb 9 02:07:11 2026 Received: from mx0a-0064b401.pphosted.com (mx0a-0064b401.pphosted.com [205.220.166.238]) (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 862EB22A1C0; Fri, 25 Apr 2025 05:38:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.166.238 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745559494; cv=none; b=gVutvOo+JlZF9VuqG0NVJJXx2BbiTtW+A4u5XzKAqAjj7rJ2eBz90PSayC3JJx0DgJXz4XKxqCtFQy9AMeOOtEXj0pz+pgsEj1sfi4syPq+a5god6sbEWa3iQ3WgEwGGTNHwAOUbcjzuj44R9BgSL4dkF0cTfBVwNTbzDyEKmjE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745559494; c=relaxed/simple; bh=tCq1TMcBi/EJFu3yiehmqYHr+5YiokYp40hNMkdBeww=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jZbaA/s3knXMGLTvdmYQ+Hn2gzsgkX/JuvWjmKOhm1NWgrHXqioLoRKNHbPkFTvWC45mRA7rasSHm8nqswbmfCPcxKQbL/+4Kq9+XR1JllDvxCrdFZKUpjtKI/MOd7wZYNotOJfCq3RtYOkhvFqKo4tf/D8Xt+/wB6ErMST/VjA= 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=205.220.166.238 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 (m0250810.ppops.net [127.0.0.1]) by mx0a-0064b401.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 53P5QRW3011328; Thu, 24 Apr 2025 22:38:07 -0700 Received: from ala-exchng02.corp.ad.wrs.com (ala-exchng02.wrs.com [147.11.82.254]) by mx0a-0064b401.pphosted.com (PPS) with ESMTPS id 466jhd3ans-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Thu, 24 Apr 2025 22:38:07 -0700 (PDT) Received: from ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) by ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.43; Thu, 24 Apr 2025 22:38:06 -0700 Received: from pek-lpd-ccm6.wrs.com (147.11.136.210) by ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) with Microsoft SMTP Server id 15.1.2507.43 via Frontend Transport; Thu, 24 Apr 2025 22:38:04 -0700 From: Lizhi Xu To: CC: , , , , , Subject: [PATCH V2] loop: Add sanity check for read/write_iter Date: Fri, 25 Apr 2025 13:38:03 +0800 Message-ID: <20250425053803.3614260-1-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=ZNDXmW7b c=1 sm=1 tr=0 ts=680b1fbf cx=c_pps a=K4BcnWQioVPsTJd46EJO2w==:117 a=K4BcnWQioVPsTJd46EJO2w==:17 a=XR8D0OoHHMoA:10 a=edf1wS77AAAA:8 a=hSkVLCK3AAAA:8 a=t7CeM3EgAAAA:8 a=5yON4tJlvpFzjYmBgeMA:9 a=DcSpbTIhAlouE1Uv7lRv:22 a=cQPPKAXgyycSBL8etih5:22 a=FdTzh2GWekK77mhwV6Dw:22 X-Proofpoint-ORIG-GUID: FpZcOjmb2kLse7D_SJIQHczlaX8wGweY X-Proofpoint-GUID: FpZcOjmb2kLse7D_SJIQHczlaX8wGweY X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNDI1MDAzOSBTYWx0ZWRfXx59o8i9e5iwR jEVbskttJzNY5b0KoXfMX9pCsi4thmrMg0SS0Pp4AfRXzm/XtAf7v7SbxveekH591b/oatynPW0 X8YDguDzrqkmvcVDU9wIl9zRHgsGq+Z6crIMJ80shEEjq3jKwEn3I9rSvgxY06+ddtYvL1fZnE+ k0+Lb1CQvbttRoy+WQH1gUV6p9+0u/pd0PYJlk0eCBbWyKDeIxECSkbZyp/AP2IFR7dAms+81cn zFTmfTQ5eocc9HifGawFvvSo3wNm4zlhYbKbr0m0D5kMCsVXpr7pwlDVBdnQCLMU5DpXOUhYret 6WHABOUB8Oj/vxZUEIaPFlWFlGbV7eq7qnlmzohFmQgm34pn6pT1OIa4RzMVXYpSHZH/QXRn8It 8x2yiHx2KnniZ664zc/x39xGkeMFjg6MB5TAbWwEgy/NnU15YH6PUe84lnLSiXVCn/UMBxTN X-Sensitive_Customer_Information: Yes X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-04-25_01,2025-04-24_02,2025-02-21_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 priorityscore=1501 clxscore=1015 adultscore=0 spamscore=0 bulkscore=0 impostorscore=0 malwarescore=0 mlxlogscore=932 mlxscore=0 suspectscore=0 phishscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.21.0-2504070000 definitions=main-2504250039 Content-Type: text/plain; charset="utf-8" Some file systems do not support read_iter or write_iter, such as selinuxfs in this issue. So before calling them, first confirm that the interface is supported and then call it. Reported-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D6af973a3b8dfd2faefdc Signed-off-by: Lizhi Xu --- V1 -> V2: move check to loop_configure and loop_change_fd drivers/block/loop.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 674527d770dc..d2651e3b5142 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -603,6 +603,12 @@ static int loop_change_fd(struct loop_device *lo, stru= ct block_device *bdev, if (!file) return -EBADF; =20 + if (unlikely(!file->f_op->read_iter)) + return -EINVAL; + + if (file->f_mode & FMODE_WRITE && unlikely(!file->f_op->write_iter)) + return -EINVAL; + /* suppress uevents while reconfiguring the device */ dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1); =20 @@ -1039,6 +1045,14 @@ static int loop_configure(struct loop_device *lo, bl= k_mode_t mode, =20 if (!file) return -EBADF; + + if (unlikely(!file->f_op->read_iter)) + return -EINVAL; + + if (((file->f_mode & FMODE_WRITE) || (mode & BLK_OPEN_WRITE)) && + unlikely(!file->f_op->write_iter)) + return -EINVAL; + is_loop =3D is_loop_device(file); =20 /* This is safe, since we have a reference from open(). */ --=20 2.43.0