From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794661788; b=0kbxMEQmCdqqyQy9iqn8h2TbAgiuHzEA5THSX6p9JRRNqzLmlcymMJ+d6bae0MDZP0n7 AALhF1L/B3v2+hGWeWzFW6tKYRbSssP7WbwUK/IMWXFvXvds1c7Bn0GyIlNxT36cb4qdI VVirDrlQ9/Wsuv4QPm08Tle6VEb0ymHCV53Jw9dtORx+quypnAqOleXvsqjTSWnhbJilD Qg5oJuUwolWQxIR34U5PjYo+LDDJLALJN9MTTlk74VuqRKaog54aFxoBtwHdO2OHgcS+z O96DWll1EfFAU3+gDP5V/wqlHCpbxxBtGJJAa6eQviK5ekyBpusYVv4fP2ewItHzXEQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794661788; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=TzlH4lJ7ZSZIblRm06H21pfwXJAWDZmkD7RxeUrwAwo=; b=feWPRbmBvaAcfSgqoWPXMSu3F1SZc5re0T8rw5bmZKEp99DvDq9EnHCMRz7dwMR5Wc6w sjF9MLGjxCojLbSKOUPx9vVpNI4O4mzPYQkjPJvuaNvqpkbD8BA+yXdUp89LFUn77u+wH 5WsMH8qF7J6IjzIeouUqAiyTK2bslZhrkf1CpDzL+xc6HvdzXG4W0F+vadRzGw3Pyk4Zr jOuzOxqA/c3yfMGDpoQggdbdmmYdq0QK/o2/Yxby/kzqHaJcJGIEvdvLCg3TTGIdhJe3x kcgF5LHhXSSiZvQZgbwG3O95ve/IIBdiytVksJCRLXHTXRs2J/nH9ePzHE8KP0cu8cA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=GlyL6zOy; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21ADC6079E1F; Sat, 14 Nov 2026 13:09:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=GlyL6zOy Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF37C1F000C5; Sat, 14 Nov 2026 13:09:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794661788; bh=TzlH4lJ7ZSZIblRm06H21pfwXJAWDZmkD7RxeUrwAwo=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=GlyL6zOy3U34aQUy3eHEQO1vIyJXeAiTdOGtABLlkjbMnvKHjyhKDScl3Hk7rbn/i bUN/hnUMxKho/1WWAiF8JiculAXTejCCuJ3FonfhnSNp937ufCy4qoRmfbGVvZHsH7 9rlf5d2C3SdZVqBTg4J8yIIUsxC5D98LB2FsGhf59wAx6+iIV/zNQO/IKTaGaMPHTI VX46CiB8pXPS+hXzwpsFz2BDETD3xysRH8Rj/RJaz/eTFDnVWydJvu5JEiwzj8rnWQ EWDXUNsiasluJEgOXK7yZCzr+ogHhW+EDBwb4kKVBL61Tujac2yGBy06BywSGLd7Mo Pny//KWEyQopg== From: Christian Brauner Date: Sat, 14 Nov 2026 14:02:17 +0100 Subject: [PATCH RFC v2 36/42] nvmet: refuse files on pseudo filesystems as namespace backing files X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261114-work-loop-pseudo-v2-36-98639a2286fb@kernel.org> References: <20261114-work-loop-pseudo-v2-0-98639a2286fb@kernel.org> In-Reply-To: <20261114-work-loop-pseudo-v2-0-98639a2286fb@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Jann Horn , Chris Mason , Josef Bacik , Christoph Hellwig , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Alexander Viro , Jan Kara , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, driver-core@lists.linux.dev, linux-mm@kvack.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, apparmor@lists.ubuntu.com, linux-nfs@vger.kernel.org, netdev@vger.kernel.org, fuse-devel@lists.linux.dev, linux-efi@vger.kernel.org, xen-devel@lists.xenproject.org, ocfs2-devel@lists.linux.dev, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-usb@vger.kernel.org, Amir Goldstein , linux-erofs@lists.ozlabs.org, linux-kselftest@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-ce4c1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1428; i=brauner@kernel.org; h=from:subject:message-id; bh=T+p95LnTvG69fzj91gxDjYpoYRzamfjNk16RgT8U7v8=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWT9iOn/sX7W5ofcrzdtZCmXtdsrsyZy06+ylnkxnetWq G9bLL97VkcpC4MYF4OsmCKLQ7tJuNxynorNRpkaMHNYmUCGMHBxCsBElN4x/E+qPMN83LkkV8+9 6emz+TtUM58mNc28vP//+pR517bGGTYz/NOw1Z5h9eBm2/zf+wUFPT6nLXtx+IKQe7yGYPaa6P/ 27ZwA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 The file backend takes any file that can be opened for reading and writing. With buffered_io=1 that includes files on procfs or sysfs which then get read and written by a kernel worker on behalf of the host. Refuse files on pseudo filesystems just like loop does by switching to file_check_backing(). Note that the helper only accepts regular files and block devices. A block device ends up in the file backend when buffered_io is set. But so far the file backend also took anything else with ->read_iter() and ->write_iter() such as character devices and FIFOs. The size of the namespace is the size of the inode which is zero for all of them. So such a namespace was unusable anyway. Refuse them. Signed-off-by: Christian Brauner (Amutable) --- drivers/nvme/target/io-cmd-file.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c index dfa8aa46188c8..2249ad3bb46d8 100644 --- a/drivers/nvme/target/io-cmd-file.c +++ b/drivers/nvme/target/io-cmd-file.c @@ -47,10 +47,9 @@ int nvmet_file_ns_enable(struct nvmet_ns *ns) return ret; } - if (!ns->file->f_op->read_iter || !ns->file->f_op->write_iter) { - ret = -EINVAL; + ret = file_check_backing(ns->file, FMODE_READ | FMODE_WRITE, S_IFBLK); + if (ret) goto err; - } nvmet_file_ns_revalidate(ns); -- 2.53.0