Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:45394 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753535AbcJKMvT (ORCPT ); Tue, 11 Oct 2016 08:51:19 -0400 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, xfs@oss.sgi.com, 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 Subject: [PATCH v27 03/21] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Date: Tue, 11 Oct 2016 14:50:38 +0200 Message-Id: <1476190256-1677-4-git-send-email-agruenba@redhat.com> In-Reply-To: <1476190256-1677-1-git-send-email-agruenba@redhat.com> References: <1476190256-1677-1-git-send-email-agruenba@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Normally, deleting a file requires MAY_WRITE access to the parent directory. With richacls, a file may be deleted with MAY_DELETE_CHILD access to the parent directory or with MAY_DELETE_SELF access to the file. To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission() when checking for delete access inside a directory, and MAY_DELETE_SELF when checking for delete access to a file itself. The MAY_DELETE_SELF permission overrides the sticky directory check. Signed-off-by: Andreas Gruenbacher Reviewed-by: J. Bruce Fields Reviewed-by: Steve French Reviewed-by: Jeff Layton --- fs/namei.c | 20 +++++++++++++------- include/linux/fs.h | 2 ++ 2 files changed, 15 insertions(+), 7 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 7290dea..c8bc9fd 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -463,9 +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. * - * 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. + * MAY_WRITE must be set in @mask whenever MAY_APPEND, MAY_CREATE_FILE, + * MAY_CREATE_DIR, or MAY_DELETE_CHILD 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) { @@ -2780,14 +2780,20 @@ static int may_delete_or_replace(struct inode *dir, struct dentry *victim, BUG_ON(victim->d_parent->d_inode != dir); audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); - error = inode_permission(dir, mask); + error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD); + if (!error && check_sticky(dir, inode)) + error = -EPERM; + if (error && IS_RICHACL(inode) && + inode_permission(inode, MAY_DELETE_SELF) == 0 && + inode_permission(dir, mask) == 0) + error = 0; if (error) return error; if (IS_APPEND(dir)) return -EPERM; - if (check_sticky(dir, inode) || IS_APPEND(inode) || - IS_IMMUTABLE(inode) || IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode)) + if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || + IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode)) return -EPERM; if (isdir) { if (!d_is_dir(victim)) @@ -2805,7 +2811,7 @@ static int may_delete_or_replace(struct inode *dir, struct dentry *victim, static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) { - return may_delete_or_replace(dir, victim, isdir, MAY_WRITE | MAY_EXEC); + return may_delete_or_replace(dir, victim, isdir, MAY_EXEC); } static int may_replace(struct inode *dir, struct dentry *victim, bool isdir) diff --git a/include/linux/fs.h b/include/linux/fs.h index 26455c6..1d6d920 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -86,6 +86,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_NOT_BLOCK 0x00000080 #define MAY_CREATE_FILE 0x00000100 #define MAY_CREATE_DIR 0x00000200 +#define MAY_DELETE_CHILD 0x00000400 +#define MAY_DELETE_SELF 0x00000800 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 2.7.4