Bug#985689: Needs CONFIG_UNICODE to mount ext4 fs with case-insensitivity feature

[Mihai Moldovan]

Package: linux
Version: 5.10.19-1

Dear maintainers


Currently, mounting an EXT4-formatted volume with the case-insensitivity feature
is impossible since CONFIG_UNICODE is not enabled in the kernel configuration.

Please consider enabling it.

I'm leaving the severity at default, since the missing feature isn't just
convenience, but actually has negative implications when mounting file systems.

If that is any argument, Ubuntu 21.04 enables the feature, too.

My best guess is that the chance of regressions is very low.



Best regards



Mihai Moldovan

[Bastian Blank]

Control: tags -1 moreinfo

On Mon, Mar 22, 2021 at 08:40:34AM +0100, Mihai Moldovan wrote:
> Currently, mounting an EXT4-formatted volume with the case-insensitivity feature
> is impossible since CONFIG_UNICODE is not enabled in the kernel configuration.

Why would anyone want to do that?

> My best guess is that the chance of regressions is very low.

In recent history it's just CVE-2021-21300.

Bastian

--
No one wants war.
-- Kirk, "Errand of Mercy", stardate 3201.7

[Debian Bug Tracking System]

Processing control commands:

> tags -1 moreinfo
Bug #985689 [linux] Needs CONFIG_UNICODE to mount ext4 fs with case-insensitivity feature
Added tag(s) moreinfo.

--
985689: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=985689
Debian Bug Tracking System
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[Mihai Moldovan]

* On 3/22/21 9:40 AM, Bastian Blank wrote:
> Control: tags -1 moreinfo
>
> On Mon, Mar 22, 2021 at 08:40:34AM +0100, Mihai Moldovan wrote:
>> Currently, mounting an EXT4-formatted volume with the case-insensitivity feature
>> is impossible since CONFIG_UNICODE is not enabled in the kernel configuration.
>
> Why would anyone want to do that?

That point is debatable. I'd like to enable it in case I'd ever need it and it's
pretty safe to do so. Even if the feature is enabled in ext4, it won't actually
be used unless explicitly enabled on a per-directory basis. It won't just make
the whole file system case-insensitive, but can be useful in niche situations
like improved wine compatibility.

In any case, I fear that the better argument (since others seem to lead to a
holy war/gut feeling route) is that e2fsprogs can create such a file system (-O
casefold), so it would be illogical to have a kernel which is not being able to
mount such a volume.

>> My best guess is that the chance of regressions is very low.
>
> In recent history it's just CVE-2021-21300.

Which was a bug in git, not the kernel side of things, as far as I can see.

The issue is that, currently, you can create such a file system and even if the
feature is not actually used (since no directory within the volume enables
case-insensitivity), the stock Debian kernel won't be able mount it.

File systems like FAT aren't just disabled in the kernel configuration just
because they happen to be case-insensitive by design.



Mihai

[Debian Bug Tracking System]

Your message dated Tue, 10 Aug 2021 07:00:09 +0000
with message-id <E1mDLk9-...@fasolo.debian.org>
and subject line Bug#985689: fixed in linux 5.13.9-1~exp1
has caused the Debian Bug report #985689,
regarding Needs CONFIG_UNICODE to mount ext4 fs with case-insensitivity feature
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

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