linux-kernel - Re: [PATCH v10 09/14] exfat: add misc operations

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

Message-ID: <CAK8P3a1ozgLYpDtveU0CtLj5fEFG8i=_QrnEAtoVFt-yC=Dc0g@mail.gmail.com>
Date:   Wed, 15 Jan 2020 14:50:10 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Pali Rohár <pali.rohar@...il.com>
Cc:     Namjae Jeon <linkinjeon@...il.com>,
        Namjae Jeon <namjae.jeon@...sung.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Linux FS-devel Mailing List <linux-fsdevel@...r.kernel.org>,
        gregkh <gregkh@...uxfoundation.org>,
        Valdis Kletnieks <valdis.kletnieks@...edu>,
        Christoph Hellwig <hch@....de>, sj1557.seo@...sung.com
Subject: Re: [PATCH v10 09/14] exfat: add misc operations

On Wed, Jan 15, 2020 at 2:38 PM Pali Rohár <pali.rohar@...il.com> wrote:
> On Wednesday 15 January 2020 22:30:59 Namjae Jeon wrote:
> > 2020-01-15 19:10 GMT+09:00, Arnd Bergmann <arnd@...db.de>:

> > It is not described in the specification. I don't know exactly what
> > the problem is because sys_tz.tz_minuteswest seems to work fine to me.
> > It can be random garbage value ?
> >
> > > so if there is a choice, falling back to UTC would
> > > be nicer.
> >
> > Okay.
>
> Arnd, what is the default value of sys_tz.tz_minuteswest? What is the
> benefit of not using it?
>
> I though that timezone mount option is just an old hack when userspace
> does not correctly set kernel's timezone and that this timezone mount
> option should be in most cases avoided.

The main problem is that it is system-wide and initialized at boot
time through settimeofday() to a timezone picked by the system
administrator.

However, in user space, every user may set their own timezone with
the 'TZ' variable, and the default timezone may be different inside of a
container based on the contents of /etc/timezone in its root directory.

> So also another question, what is benefit of having fs specific timezone
> mount option? As it is fs specific it means that it would be used so
> much.

You can use it to access removable media that were written in
a different timezone, or a partition that is shared with another OS
running on the same machine but with different timezone settings.

     Arnd