From patchwork Fri May 5 08:11:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiu Jianfeng X-Patchwork-Id: 13232247 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06445C7EE2C for ; Fri, 5 May 2023 08:13:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231302AbjEEINc (ORCPT ); Fri, 5 May 2023 04:13:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231139AbjEEINa (ORCPT ); Fri, 5 May 2023 04:13:30 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 710981634D; Fri, 5 May 2023 01:13:29 -0700 (PDT) Received: from dggpeml500023.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4QCNgb2Bb0zsR53; Fri, 5 May 2023 16:11:39 +0800 (CST) Received: from ubuntu1804.huawei.com (10.67.174.58) by dggpeml500023.china.huawei.com (7.185.36.114) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Fri, 5 May 2023 16:13:26 +0800 From: Xiu Jianfeng To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: , , , , , , , , , Subject: [PATCH -next 0/2] lsm: Change inode_setattr() to take struct Date: Fri, 5 May 2023 16:11:58 +0800 Message-ID: <20230505081200.254449-1-xiujianfeng@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.67.174.58] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpeml500023.china.huawei.com (7.185.36.114) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Hi, I am working on adding xattr/attr support for landlock [1], so we can control fs accesses such as chmod, chown, uptimes, setxattr, etc.. inside landlock sandbox. the LSM hooks as following are invoved: 1.inode_setattr 2.inode_setxattr 3.inode_removexattr 4.inode_set_acl 5.inode_remove_acl which are controlled by LANDLOCK_ACCESS_FS_WRITE_METADATA. and 1.inode_getattr 2.inode_get_acl 3.inode_getxattr 4.inode_listxattr which are controlled by LANDLOCK_ACCESS_FS_READ_METADATA Some of these hooks only take struct dentry as a argument, However, for path-based LSMs such Landlock, Apparmor and Tomoyo, struct path instead of struct dentry required to make sense of attr/xattr accesses. So we need to refactor these hooks to take a struct path argument. This patchset only refators inode_setattr hook as part of whole work. Also, I have a problem about file_dentry() in __file_remove_privs() of the first patch, before changes in commit c1892c37769cf ("vfs: fix deadlock in file_remove_privs() on overlayfs"), it gets dentry and inode as belows: struct dentry *dentry = file->f_path.dentry; struct inode *inode = d_inode(dentry); That would be clear to change it to pass &file->f_path to __remove_privs()->notify_change()->inode_setattr(). After that commit, it has been changed to: struct dentry *dentry = file_dentry(file); struct inode *inode = file_inode(file); If I understand correctly, the dentry from file_dentry() maybe the upper or the lower, it can be different from file->f_path.dentry. It can't just go back to use &file->f_path otherwise the bug will come back for overlayfs. So for such scenario, how to get a path from file if the file maybe or not from overlayfs, and which kind of overlayfs path is ok for Landlock? Xiu Jianfeng (2): fs: Change notify_change() to take struct path argument lsm: Change inode_setattr hook to take struct path argument drivers/base/devtmpfs.c | 5 +++-- fs/attr.c | 7 ++++--- fs/cachefiles/interface.c | 4 ++-- fs/coredump.c | 2 +- fs/ecryptfs/inode.c | 18 +++++++++--------- fs/fat/file.c | 2 +- fs/inode.c | 8 +++++--- fs/ksmbd/smb2pdu.c | 6 +++--- fs/ksmbd/smbacl.c | 2 +- fs/namei.c | 2 +- fs/nfsd/vfs.c | 12 ++++++++---- fs/open.c | 19 ++++++++++--------- fs/overlayfs/overlayfs.h | 4 +++- fs/utimes.c | 2 +- include/linux/fs.h | 4 ++-- include/linux/lsm_hook_defs.h | 2 +- include/linux/security.h | 4 ++-- security/security.c | 10 +++++----- security/selinux/hooks.c | 3 ++- security/smack/smack_lsm.c | 5 +++-- 20 files changed, 67 insertions(+), 54 deletions(-)