From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754863AbcGELHy (ORCPT ); Tue, 5 Jul 2016 07:07:54 -0400 Received: from mail-qk0-f180.google.com ([209.85.220.180]:36557 "EHLO mail-qk0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754821AbcGELHu (ORCPT ); Tue, 5 Jul 2016 07:07:50 -0400 Message-ID: <1467716867.3800.4.camel@redhat.com> Subject: Re: [PATCH v23 03/22] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags From: Jeff Layton To: Andreas Gruenbacher , Alexander Viro Cc: Christoph Hellwig , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , 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 Date: Tue, 05 Jul 2016 07:07:47 -0400 In-Reply-To: <1467294433-3222-4-git-send-email-agruenba@redhat.com> References: <1467294433-3222-1-git-send-email-agruenba@redhat.com> <1467294433-3222-4-git-send-email-agruenba@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2 (3.18.5.2-1.fc23) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2016-06-30 at 15:46 +0200, Andreas Gruenbacher wrote: > 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. > Minor misspelling in changelog above. It should be "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 > --- >  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 dc91858..663933e 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -454,9 +454,9 @@ 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) >  { > @@ -2778,14 +2778,18 @@ 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)) > @@ -2803,7 +2807,7 @@ 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 dd614ad..86bfa10 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 Reviewed-by: Jeff Layton