why is os-prober disabled by default

[digitalmailing]

Hello,

Is there a reason why GRUB_DISABLE_OS_PROBER=false
in /etc/default/grub is commented by default after

installation of bookworm or grub?

For me uncommenting is no big problem to do, cause i know where to. But for new users, with maybe dualboot windows, not showing up after installation of bookworm this might be.

(this happend to a friend of mine after i persuaded him to use linux).

After some updating with discovery(kde) os-prober is commented again
in /etc/default/grub (it was uncommented before).

(no other lines i edited are changed)

Does it happen to you? And why would you want that?

I find this very annoying and inconvenient to change it back again after some updates.

Or is there a good reason why its commended  after updates?

Regards

Felix

[Teemu Likonen]

* 2023-07-14 20:32:41+0200, digital...@gmx.de wrote:

> Is there a reason why GRUB_DISABLE_OS_PROBER=false in
> /etc/default/grub is commented by default after installation of
> bookworm or grub?

Yes. Release notes document tells about it briefly:

5.1.11. GRUB no longer runs os-prober by default

For a long time, grub has used the os-prober package to detect other
operating systems installed on a computer so that it can add them to
the boot menu. Unfortunately, that can be problematic in certain
cases (e.g. where guest virtual machines are running), so this has
now been disabled by default in the latest upstream release.

https://www.debian.org/releases/stable/amd64/release-notes/ch-information.en.html#grub-os-prober

--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: 6965F03973F0D4CA22B9410F0F2CAE0E07608462

[Dan Ritter]

digitalmailing wrote:
> Is there a reason why GRUB_DISABLE_OS_PROBER=false
> in /etc/default/grub is commented by default after
> installation of bookworm or grub?

Yes. It's a new change, mentioned in the upgrade notes.

https://www.debian.org/releases/bookworm/amd64/release-notes/ch-information.en.html#grub-os-prober

-dsr-

[Andy Smith]

Hi,

On Fri, Jul 14, 2023 at 08:32:41PM +0200, digitalmailing wrote:
> I find this very annoying and inconvenient to change

> [GRUB_DISABLE_OS_PROBER] back again after some updates.

Others have explained the "why". To stop your changes being
overwritten you can re-enable it in a .cfg file in
/etc/default/grub.d/.

Cheers,
Andy

--
https://bitfolk.com/ -- No-nonsense VPS hosting

[Brian]

On Fri 14 Jul 2023 at 21:41:39 +0300, Teemu Likonen wrote:

> * 2023-07-14 20:32:41+0200, digital...@gmx.de wrote:
>
> > Is there a reason why GRUB_DISABLE_OS_PROBER=false in
> > /etc/default/grub is commented by default after installation of
> > bookworm or grub?
>
> Yes. Release notes document tells about it briefly:
>
> 5.1.11. GRUB no longer runs os-prober by default
>
> For a long time, grub has used the os-prober package to detect other
> operating systems installed on a computer so that it can add them to
> the boot menu. Unfortunately, that can be problematic in certain
> cases (e.g. where guest virtual machines are running), so this has
> now been disabled by default in the latest upstream release.
>
> https://www.debian.org/releases/stable/amd64/release-notes/ch-information.en.html#grub-os-prober

Most Debian users experience of guest virtual machines is likely to be
minimal, so the impact of having GRUB_DISABLE_OS_PROBER=false falls on
the majority. The change is is an upstream one and Debian tends not
to go against such changes. This is the likely reason for not altering
what upstream has determined.

The reason for upstream's decision appears to be:

os-prober is inherently insecure as it mounts all partitions
on your disk using grub-mount to check them for other OS,
which is not a nice thing to do as root as you can exploit
bugs in the filesystem code easily.

--
Brian

[Max Nikulin]

On 15/07/2023 01:32, digitalmailing wrote:
> Is there a reason why GRUB_DISABLE_OS_PROBER=false
> in /etc/default/grub is commented by default after
>
> installation of bookworm or grub?

After posting some links and references to Debian bugs in

Re: os-prober Just a Rant. Fri, 26 May 2023 09:38:37 +0700.
https://lists.debian.org/msgid-search/u4p63e$103m$1...@ciao.gmane.io

I have noticed the following:

https://www.debian.org/devel/debian-installer/News/2023/20230428
Debian Installer Bookworm RC 2 release
April 28th, 2023

> grub-installer:
>
> - If we detect other operating systems installed, check with the user
> (at low priority) and re-enable os-prober.

So I am curious if it has been reverted later or it is the part of the
release.

Perhaps the same logic may be implemented in package upgrade scripts.