Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933553AbbHDLyj (ORCPT ); Tue, 4 Aug 2015 07:54:39 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:32781 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932776AbbHDLyd (ORCPT ); Tue, 4 Aug 2015 07:54:33 -0400 From: Andreas Gruenbacher X-Google-Original-From: Andreas Gruenbacher To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-api@vger.kernel.org, linux-cifs@vger.kernel.org, linux-security-module@vger.kernel.org, Andreas Gruenbacher Subject: [RFC v6 03/40] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Date: Tue, 4 Aug 2015 13:53:01 +0200 Message-Id: <1438689218-6921-4-git-send-email-agruenba@redhat.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1438689218-6921-1-git-send-email-agruenba@redhat.com> References: <1438689218-6921-1-git-send-email-agruenba@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2950 Lines: 78 Normally, deleting a file requires write and execute access to the parent directory. With Richacls, a process with MAY_DELETE_SELF access to a file may delete the file even without write access to the parent directory. 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 does not override the sticky directory check. It probably should. Signed-off-by: Andreas Gruenbacher --- fs/namei.c | 15 +++++++++++---- include/linux/fs.h | 2 ++ 2 files changed, 13 insertions(+), 4 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 3504d36..2ac759c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -454,7 +454,7 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask) * changing the "normal" UIDs which are used for other things. * * When checking for MAY_APPEND, MAY_CREATE_FILE, MAY_CREATE_DIR, - * MAY_WRITE must also be set in @mask. + * MAY_DELETE_CHILD, MAY_DELETE_SELF, MAY_WRITE must also be set in @mask. */ int inode_permission(struct inode *inode, int mask) { @@ -2527,7 +2527,7 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir, bool replace) { struct inode *inode = d_backing_inode(victim); - int error, mask = MAY_WRITE | MAY_EXEC; + int error, mask = MAY_EXEC; if (d_is_negative(victim)) return -ENOENT; @@ -2537,8 +2537,15 @@ static int may_delete(struct inode *dir, struct dentry *victim, audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); if (replace) - mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE; - error = inode_permission(dir, mask); + mask |= MAY_WRITE | (isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE); + error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD); + if (error && IS_RICHACL(inode)) { + /* Deleting is also permitted with MAY_EXEC on the directory + * and MAY_DELETE_SELF on the inode. */ + if (!inode_permission(inode, MAY_DELETE_SELF) && + !inode_permission(dir, mask)) + error = 0; + } if (error) return error; if (IS_APPEND(dir)) diff --git a/include/linux/fs.h b/include/linux/fs.h index 9c44f27..abf5b0e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -83,6 +83,8 @@ 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 -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/