From mboxrd@z Thu Jan 1 00:00:00 1970 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 19E55C4321E for ; Tue, 18 Oct 2022 11:57:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230248AbiJRL5o (ORCPT ); Tue, 18 Oct 2022 07:57:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230162AbiJRL5l (ORCPT ); Tue, 18 Oct 2022 07:57:41 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72E10BBF21; Tue, 18 Oct 2022 04:57:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 24C47B81D8C; Tue, 18 Oct 2022 11:57:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4ED2BC43470; Tue, 18 Oct 2022 11:57:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666094246; bh=KOxsftWRjFNhddxosHic0HvFDjcmK8lm2GExwH7ASS0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MrEU5qAQoRlLDNgrV1A11kH2x117HiAJAlXc3J8ucH0mX8OSOWKwedzPzUCqbgx9y 20MF7zBAWq/ayb1l1qlYN8Pwiu5vpcqrJUpjO4CMZaM9GoXWtYDtvkAa4BWdqX72pf 0g/JpJXXQIbl6q8dDaM20flkcsehfxqkQ0BxBdMsJq1XJCDUSLDcMTZk0f+bPbjQy/ ou/wfS2QUhwZkPU266UJP9GSS9hVKuqORLHT0qjKuVoh7R6Kl7j9dksAXIBY+Ssftv zVYZvLNR7DYkK2gobbJaIMUfq62nYIBd8yB75qUdwpkTJ//VmEXz2IBVnSf+D9mQcX 1MQ7Y1LIDJxLQ== From: Christian Brauner To: linux-fsdevel@vger.kernel.org Cc: Christian Brauner , Seth Forshee , Christoph Hellwig , Al Viro , linux-security-module@vger.kernel.org Subject: [PATCH v5 04/30] fs: add new get acl method Date: Tue, 18 Oct 2022 13:56:34 +0200 Message-Id: <20221018115700.166010-5-brauner@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221018115700.166010-1-brauner@kernel.org> References: <20221018115700.166010-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4061; i=brauner@kernel.org; h=from:subject; bh=KOxsftWRjFNhddxosHic0HvFDjcmK8lm2GExwH7ASS0=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMST7TVENtehcZsq0ZuZkH+vjGyU+6FjyGK9RF6x5EntT4ux7 MUHrjlIWBjEuBlkxRRaHdpNwueU8FZuNMjVg5rAygQxh4OIUgInUfGJk2CphUJ4Xyqtgt+7EA4uGgP qD6ptmGQqGO2zYlKc98Sp3CyPD4a1iJivea367ExKjf/a5d5uSokhYB/M/Hs3TCr9Wv/RlAQA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. Since some filesystem rely on the dentry being available to them when setting posix acls (e.g., 9p and cifs) they cannot rely on the old get acl inode operation to retrieve posix acl and need to implement their own custom handlers because of that. In a previous patch we renamed the old get acl inode operation to ->get_inode_acl(). We decided to rename it and implement a new one since ->get_inode_acl() is called generic_permission() and inode_permission() both of which can be called during an filesystem's ->permission() handler. So simply passing a dentry argument to ->get_acl() would have amounted to also having to pass a dentry argument to ->permission(). We avoided that change. This adds a new ->get_acl() inode operations which takes a dentry argument which filesystems such as 9p, cifs, and overlayfs can implement to get posix acls. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Signed-off-by: Christian Brauner (Microsoft) --- Notes: /* v2 */ unchanged /* v3 */ unchanged /* v4 */ unchanged /* v5 */ unchanged Documentation/filesystems/locking.rst | 2 ++ Documentation/filesystems/vfs.rst | 1 + include/linux/fs.h | 2 ++ 3 files changed, 5 insertions(+) diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index 0eebbbb299da..408cffe4e9a5 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -84,6 +84,7 @@ prototypes:: int (*fileattr_set)(struct user_namespace *mnt_userns, struct dentry *dentry, struct fileattr *fa); int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa); + struct posix_acl * (*get_acl)(struct user_namespace *, struct dentry *, int); locking rules: all may block @@ -105,6 +106,7 @@ get_link: no setattr: exclusive permission: no (may not block if called in rcu-walk mode) get_inode_acl: no +get_acl: no getattr: no listxattr: no fiemap: no diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index cebede60db98..2c15e7053113 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -443,6 +443,7 @@ As of kernel 2.6.22, the following members are defined: int (*atomic_open)(struct inode *, struct dentry *, struct file *, unsigned open_flag, umode_t create_mode); int (*tmpfile) (struct user_namespace *, struct inode *, struct file *, umode_t); + struct posix_acl * (*get_acl)(struct user_namespace *, struct dentry *, int); int (*set_acl)(struct user_namespace *, struct dentry *, struct posix_acl *, int); int (*fileattr_set)(struct user_namespace *mnt_userns, struct dentry *dentry, struct fileattr *fa); diff --git a/include/linux/fs.h b/include/linux/fs.h index 2395e1388e2e..255f6eff89d7 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2172,6 +2172,8 @@ struct inode_operations { umode_t create_mode); int (*tmpfile) (struct user_namespace *, struct inode *, struct file *, umode_t); + struct posix_acl *(*get_acl)(struct user_namespace *, struct dentry *, + int); int (*set_acl)(struct user_namespace *, struct dentry *, struct posix_acl *, int); int (*fileattr_set)(struct user_namespace *mnt_userns, -- 2.34.1