linux-kernel - Re: [experimental PATCH] ovl: get rid of d

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAJfpegs4R+MhZjmJabS8u6qGZuHi40MikeeWkyDq7SFj5_9USg@mail.gmail.com>
Date:   Fri, 15 Sep 2017 19:11:12 +0200
From:   Miklos Szeredi <miklos@...redi.hu>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        "linux-unionfs@...r.kernel.org" <linux-unionfs@...r.kernel.org>
Subject: Re: [experimental PATCH] ovl: get rid of d_real()

On Fri, Sep 15, 2017 at 4:07 PM, Al Viro <viro@...iv.linux.org.uk> wrote:
> On Fri, Sep 15, 2017 at 03:58:05PM +0200, Miklos Szeredi wrote:
>> And here's the prototype.  Poof, d_real() is gone.
>>
>> It definitely has got problems, but just maybe it can be made better than the
>> current mess.  It *does* solve the ro-rw inconsistency for normal reads (not
>> mmaps).
>
> ... and makes for mind-boggling amount of opening/closing the files on underlying
> filesystem.  Doing that on sodding ->read_iter() is simply wrong.

I said it is a prototype.  Caching the open files on the underlying fs
would solve that.

>  And you are
> using the wrong credentials for those opens, anyway - it should be creds of opener,
> not reader.

Actually it should be credentials of mounter, as is now done
consistently across overlayfs.

And a bunch of other issues, probably.

Thanks,
Miklos