linux-kernel - Re: LVM snapshot broke between 4.14 and 4.16

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: <20180803133102.GA3092@redhat.com>
Date:   Fri, 3 Aug 2018 09:31:03 -0400
From:   Mike Snitzer <snitzer@...hat.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     wgh@...lan.ru, Ilya Dryomov <idryomov@...il.com>,
        Jens Axboe <axboe@...nel.dk>,
        linux-block <linux-block@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Sagi Grimberg <sagi@...mberg.me>, dm-devel@...hat.com
Subject: Re: LVM snapshot broke between 4.14 and 4.16

On Thu, Aug 02 2018 at  5:52pm -0400,
Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> On Thu, Aug 2, 2018 at 2:39 PM WGH <wgh@...lan.ru> wrote:
> >
> > I've just found one public report of this bug, though:
> > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=900442
> 
> Yeah, it does sound like we should fix this issue.

Debian is notorious for having a stale and/or custom lvm2.
Generally speaking, it is recommended that lvm2 not be older than the
kernel (but the opposite is fine).  

Given the narrow scope of users impacted (read-only snapshot creation is
very niche, certainly not the default): I don't think it is worth making
fiddly changes in dm-snapshot to warn the user and override the
permissions for the cow device.

Mike