From patchwork Mon Feb 13 15:32:18 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 9570177 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1399260578 for ; Mon, 13 Feb 2017 15:45:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0AA2D28356 for ; Mon, 13 Feb 2017 15:45:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F210328394; Mon, 13 Feb 2017 15:45:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5C58F28358 for ; Mon, 13 Feb 2017 15:45:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753661AbdBMPpm (ORCPT ); Mon, 13 Feb 2017 10:45:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54302 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752981AbdBMPcv (ORCPT ); Mon, 13 Feb 2017 10:32:51 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 541B7C04B937; Mon, 13 Feb 2017 15:32:52 +0000 (UTC) Received: from nux.redhat.com (ovpn-117-141.ams2.redhat.com [10.36.117.141]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1DFWd4M006129; Mon, 13 Feb 2017 10:32:47 -0500 From: Andreas Gruenbacher To: Alexander Viro Cc: Andreas Gruenbacher , Christoph Hellwig , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker , Dave Chinner , linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-api@vger.kernel.org, Miklos Szeredi , "J . Bruce Fields" , Andreas Dilger , Steve French , Jeff Layton Subject: [PATCH v28 02/21] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Date: Mon, 13 Feb 2017 16:32:18 +0100 Message-Id: <1486999957-2381-3-git-send-email-agruenba@redhat.com> In-Reply-To: <1486999957-2381-1-git-send-email-agruenba@redhat.com> References: <1486999957-2381-1-git-send-email-agruenba@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 13 Feb 2017 15:32:52 +0000 (UTC) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Richacls distinguish between creating non-directories and directories. To support that, add an isdir parameter to may_create(). When checking inode_permission() for create permission, pass in MAY_CREATE_FILE or MAY_CREATE_DIR as an additional mask flag. Add may_replace() to allow checking for delete as well as create access when replacing an existing file in vfs_rename(). Signed-off-by: Andreas Gruenbacher Cc: Miklos Szeredi Cc: J. Bruce Fields Cc: Andreas Dilger Cc: Steve French Cc: Jeff Layton --- fs/namei.c | 69 +++++++++++++++++++++++++++++++++++++----------------- include/linux/fs.h | 2 ++ 2 files changed, 49 insertions(+), 22 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 81ae757..4cc7064 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -463,7 +463,9 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask) * this, letting us set arbitrary permissions for filesystem access without * changing the "normal" UIDs which are used for other things. * - * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. + * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, or + * MAY_CREATE_DIR are set. That way, file systems that don't support these + * permissions will check for MAY_WRITE instead. */ int inode_permission(struct inode *inode, int mask) { @@ -2732,7 +2734,8 @@ EXPORT_SYMBOL(__check_sticky); * 11. We don't allow removal of NFS sillyrenamed files; it's handled by * nfs_async_unlink(). */ -static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) +static int may_delete_or_replace(struct inode *dir, struct dentry *victim, + bool isdir, int mask) { struct inode *inode = d_backing_inode(victim); int error; @@ -2744,7 +2747,7 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) BUG_ON(victim->d_parent->d_inode != dir); audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); - error = inode_permission(dir, MAY_WRITE | MAY_EXEC); + error = inode_permission(dir, mask); if (error) return error; if (IS_APPEND(dir)) @@ -2767,6 +2770,20 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) return 0; } +static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) +{ + return may_delete_or_replace(dir, victim, isdir, MAY_WRITE | MAY_EXEC); +} + +static int may_replace(struct inode *dir, struct dentry *victim, + bool isdir, bool new_isdir) +{ + int mask = new_isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; + + return may_delete_or_replace(dir, victim, isdir, + mask | MAY_WRITE | MAY_EXEC); +} + /* Check whether we can create an object with dentry child in directory * dir. * 1. We can't do it if child already exists (open has special treatment for @@ -2776,9 +2793,11 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) * 4. We should have write and exec permissions on dir * 5. We can't do it if dir is immutable (done in permission()) */ -static inline int may_create(struct inode *dir, struct dentry *child) +static inline int may_create(struct inode *dir, struct dentry *child, bool isdir) { + int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; struct user_namespace *s_user_ns; + audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE); if (child->d_inode) return -EEXIST; @@ -2788,7 +2807,7 @@ static inline int may_create(struct inode *dir, struct dentry *child) if (!kuid_has_mapping(s_user_ns, current_fsuid()) || !kgid_has_mapping(s_user_ns, current_fsgid())) return -EOVERFLOW; - return inode_permission(dir, MAY_WRITE | MAY_EXEC); + return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask); } /* @@ -2838,7 +2857,7 @@ EXPORT_SYMBOL(unlock_rename); int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool want_excl) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, false); if (error) return error; @@ -3624,7 +3643,7 @@ EXPORT_SYMBOL(user_path_create); int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, false); if (error) return error; @@ -3718,7 +3737,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, true); unsigned max_links = dir->i_sb->s_max_links; if (error) @@ -3774,7 +3793,7 @@ SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode) int vfs_rmdir(struct inode *dir, struct dentry *dentry) { - int error = may_delete(dir, dentry, 1); + int error = may_delete(dir, dentry, true); if (error) return error; @@ -3896,7 +3915,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname) int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode) { struct inode *target = dentry->d_inode; - int error = may_delete(dir, dentry, 0); + int error = may_delete(dir, dentry, false); if (error) return error; @@ -4030,7 +4049,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname) int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, false); if (error) return error; @@ -4113,7 +4132,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de if (!inode) return -ENOENT; - error = may_create(dir, new_dentry); + error = may_create(dir, new_dentry, false); if (error) return error; @@ -4308,19 +4327,25 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (source == target) return 0; - error = may_delete(old_dir, old_dentry, is_dir); - if (error) - return error; - if (!target) { - error = may_create(new_dir, new_dentry); + error = may_delete(old_dir, old_dentry, is_dir); + if (error) + return error; + error = may_create(new_dir, new_dentry, is_dir); } else { new_is_dir = d_is_dir(new_dentry); - if (!(flags & RENAME_EXCHANGE)) - error = may_delete(new_dir, new_dentry, is_dir); - else - error = may_delete(new_dir, new_dentry, new_is_dir); + if (!(flags & RENAME_EXCHANGE)) { + error = may_delete(old_dir, old_dentry, is_dir); + if (error) + return error; + error = may_replace(new_dir, new_dentry, is_dir, is_dir); + } else { + error = may_replace(old_dir, old_dentry, is_dir, new_is_dir); + if (error) + return error; + error = may_replace(new_dir, new_dentry, new_is_dir, is_dir); + } } if (error) return error; @@ -4574,7 +4599,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna int vfs_whiteout(struct inode *dir, struct dentry *dentry) { - int error = may_create(dir, dentry); + int error = may_create(dir, dentry, false); if (error) return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index 41042ce..7141760 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -84,6 +84,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_CHDIR 0x00000040 /* called from RCU mode, don't block */ #define MAY_NOT_BLOCK 0x00000080 +#define MAY_CREATE_FILE 0x00000100 +#define MAY_CREATE_DIR 0x00000200 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond