Re: Unicode conversion issue

From: Jaegeuk Kim
Date: Wed Dec 11 2024 - 12:08:42 EST


On 12/11, Gabriel Krisman Bertazi wrote:
> Jaegeuk Kim <jaegeuk@xxxxxxxxxx> writes:
>
> > Hi Linus/Gabriel,
> >
> > Once Android applied the below patch [1], some special characters started to be
> > converted differently resulting in different length, so that f2fs cannot find
> > the filename correctly which was created when the kernel didn't have [1].
> >
> > There is one bug report in [2] where describes more details. In order to avoid
> > this, could you please consider reverting [1] asap? Or, is there any other
> > way to keep the conversion while addressing CVE? It's very hard for f2fs to
> > distinguish two valid converted lengths before/after [1].
>
> I got this report yesterday. I'm looking into it.
>
> It seems commit 5c26d2f1d3f5 ("unicode: Don't special case ignorable
> code points") has affected more than ignorable code points, because that
> U+2764 is not marked as Ignorable in the unicode database.
>
> I still think the solution to the original issue is eliminating
> ignorable code points, and that should be fine. Let me look at why this
> block of characters is mishandled.

Thank you so much. If it takes some time to find the root cause, may I
propose the revert first to unblock production? The problem is quite severe
as users cannot access their files.

>
> >
> > [1] 5c26d2f1d3f5 ("unicode: Don't special case ignorable code points")
> > [2] https://bugzilla.kernel.org/show_bug.cgi?id=219586
>
> --
> Gabriel Krisman Bertazi