Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:40641 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752292AbcB2IRn (ORCPT ); Mon, 29 Feb 2016 03:17:43 -0500 From: Andreas Gruenbacher To: Alexander Viro Cc: "J. Bruce Fields" , linux-nfs@vger.kernel.org, "Theodore Ts'o" , linux-cifs@vger.kernel.org, linux-api@vger.kernel.org, Trond Myklebust , linux-kernel@vger.kernel.org, xfs@oss.sgi.com, Christoph Hellwig , Andreas Dilger , linux-fsdevel@vger.kernel.org, Jeff Layton , linux-ext4@vger.kernel.org, Anna Schumaker Subject: [PATCH v18 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Date: Mon, 29 Feb 2016 09:17:08 +0100 Message-Id: <1456733847-17982-4-git-send-email-agruenba@redhat.com> In-Reply-To: <1456733847-17982-1-git-send-email-agruenba@redhat.com> References: <1456733847-17982-1-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 itelf. The MAY_DELETE_SELF permission overrides the sticky directory check. Signed-off-by: Andreas Gruenbacher Reviewed-by: J. Bruce Fields --- fs/namei.c | 20 ++++++++++++-------- include/linux/fs.h | 2 ++ 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index ae30626..59b1da0 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -453,9 +453,9 @@ 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) { @@ -2626,14 +2626,18 @@ 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)) + if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) return -EPERM; if (isdir) { if (!d_is_dir(victim)) @@ -2651,7 +2655,7 @@ 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 02e99d7..97e34ba 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -85,6 +85,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate); #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 -- 2.4.3