From patchwork Wed Sep 28 16:08:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12992522 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 7A401C6FA8E for ; Wed, 28 Sep 2022 16:13:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234652AbiI1QNv (ORCPT ); Wed, 28 Sep 2022 12:13:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234555AbiI1QNf (ORCPT ); Wed, 28 Sep 2022 12:13:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B47B93524; Wed, 28 Sep 2022 09:13:32 -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 dfw.source.kernel.org (Postfix) with ESMTPS id D85A461F2A; Wed, 28 Sep 2022 16:13:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C762DC433B5; Wed, 28 Sep 2022 16:13:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664381610; bh=glgYfCgOF1Wc4bvysoyf7uZOZdSilyI+YjpLPMy4mzw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QsPm2/C6o+NjTYr4CXfiYmZfEE988t8ZiQgFeTbOvlZks8e8VxS4CTqclrVNWmyo4 wCwCx7FhAXw7DwGjZjyIvWNmthmgkeyCdfiCUB6Jzr5PBC/gaANaeCi/1kEgD2VDpd ZVoFJhJLoJwKKi2/9lOCo3013pFYEigGpq3TyrR/5AItfr0RIQyr/cQlIpfk9aGdAN l3Wuc0eeXywC6lLytW2hm1QCUP4AdwuyUoPHRjba/6Jb8+LY1HIiu6y8NHH5moSVUL 5YU2XpOOJObNcJJ+mk1gi6PVm2Ekzi/KdIJLbe1Jwf9OVXL0O1Z+vqgez8Vr8Icxoa JPcDmIPrVm3xw== 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 v3 16/29] acl: add vfs_remove_acl() Date: Wed, 28 Sep 2022 18:08:30 +0200 Message-Id: <20220928160843.382601-17-brauner@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220928160843.382601-1-brauner@kernel.org> References: <20220928160843.382601-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5329; i=brauner@kernel.org; h=from:subject; bh=glgYfCgOF1Wc4bvysoyf7uZOZdSilyI+YjpLPMy4mzw=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSSbFNZOeHPLLH/mnjrWJS//acbeqZR56DlnYnN4z85+1h51 pdr8jlIWBjEuBlkxRRaHdpNwueU8FZuNMjVg5rAygQxh4OIUgIn0KTAyPN0RP8HgNM/Z/8xxobwubu JbTVPeNT49fTjz5gKFmXtTLjIy7JndLD3HxNXx9cFpWW7Wqbnm8SLL926Zse+gBH95W3QmIwA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org In previous patches we implemented get and set inode operations for all non-stacking filesystems that support posix acls but didn't yet implement get and/or set acl inode operations. This specifically affected cifs and 9p. Now we can build a posix acl api based solely on get and set inode operations. We add a new vfs_remove_acl() api that can be used to set posix acls. This finally removes all type unsafety and type conversion issues explained in detail in [1] that we aim to get rid of. After we finished building the vfs api we can switch stacking filesystems to rely on the new posix api and then finally switch the xattr system calls themselves to rely on the posix acl api. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Signed-off-by: Christian Brauner (Microsoft) --- Notes: /* v2 */ unchanged /* v3 */ unchanged fs/posix_acl.c | 65 +++++++++++++++++++++++++++++++++++++++ include/linux/evm.h | 13 ++++++++ include/linux/posix_acl.h | 8 +++++ 3 files changed, 86 insertions(+) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 4a6ee5425488..68a63750772d 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -1484,3 +1484,68 @@ struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, return acl; } EXPORT_SYMBOL(vfs_get_acl); + +/** + * vfs_remove_acl - remove posix acls + * @mnt_userns: user namespace of the mount + * @dentry: the dentry based on which to retrieve the posix acls + * @acl_name: the name of the posix acl + * + * This function removes posix acls. + * + * Return: On success 0, on error negative errno. + */ +int vfs_remove_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *acl_name) +{ + int acl_type; + int error; + struct inode *inode = d_inode(dentry); + struct inode *delegated_inode = NULL; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return -EINVAL; + +retry_deleg: + inode_lock(inode); + + /* + * We only care about restrictions the inode struct itself places upon + * us otherwise POSIX ACLs aren't subject to any VFS restrictions. + */ + error = xattr_permission(mnt_userns, inode, acl_name, MAY_WRITE); + if (error) + goto out_inode_unlock; + + error = security_inode_remove_acl(mnt_userns, dentry, acl_name); + if (error) + goto out_inode_unlock; + + error = try_break_deleg(inode, &delegated_inode); + if (error) + goto out_inode_unlock; + + if (inode->i_opflags & IOP_XATTR) + error = set_posix_acl(mnt_userns, dentry, acl_type, NULL); + else if (unlikely(is_bad_inode(inode))) + error = -EIO; + else + error = -EOPNOTSUPP; + if (!error) { + fsnotify_xattr(dentry); + evm_inode_post_remove_acl(mnt_userns, dentry, acl_name); + } + +out_inode_unlock: + inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + + return error; +} +EXPORT_SYMBOL(vfs_remove_acl); diff --git a/include/linux/evm.h b/include/linux/evm.h index 117ac01b2432..7a9ee2157f69 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -35,6 +35,12 @@ extern int evm_inode_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, const char *xattr_name); extern void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name); +static inline void evm_inode_post_remove_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, + const char *acl_name) +{ + evm_inode_post_removexattr(dentry, acl_name); +} extern int evm_inode_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl); @@ -123,6 +129,13 @@ static inline void evm_inode_post_removexattr(struct dentry *dentry, return; } +static inline void evm_inode_post_remove_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, + const char *acl_name) +{ + return; +} + static inline int evm_inode_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h index 06e65b1c6e28..c5dd541babc0 100644 --- a/include/linux/posix_acl.h +++ b/include/linux/posix_acl.h @@ -104,6 +104,8 @@ int vfs_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl); struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, struct dentry *dentry, const char *acl_name); +int vfs_remove_acl(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *acl_name); #else static inline int posix_acl_chmod(struct user_namespace *mnt_userns, struct dentry *dentry, umode_t mode) @@ -145,6 +147,12 @@ static inline struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, { return NULL; } + +static inline int vfs_remove_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *acl_name) +{ + return 0; +} #endif /* CONFIG_FS_POSIX_ACL */ struct posix_acl *get_acl(struct inode *inode, int type);