linux-kernel - Re: [PATCH 2/4] UBIFS: Add xattr support for symlinks

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Date:	Tue, 11 Nov 2014 12:17:53 +0200
From:	Artem Bityutskiy <dedekind1@...il.com>
To:	Ben Shelton <ben.shelton@...com>
Cc:	linux-mtd@...ts.infradead.org, adrian.hunter@...el.com,
	linux-kernel@...r.kernel.org,
	Subodh Nijsure <snijsure@...d-net.com>,
	Marc Kleine-Budde <mkl@...gutronix.de>
Subject: Re: [PATCH 2/4] UBIFS: Add xattr support for symlinks

On Mon, 2014-11-10 at 11:12 -0600, Ben Shelton wrote:
> On 11/10, Artem Bityutskiy wrote:
> > Could you please re-test this with any kernel and carefully verify
> > symlinks. I think this should not work, because in case of symlinks we
> > already store the link target path in the inode, and with this patch the
> > target patch will be over-written with the SELinux label. I expect this
> > to be seen easily on testing - symlink targets should be corrupted.
> > 
> > Artem.
> > 
> 
> I retested this with a 3.18-rc3 kernel on one of our ARM-based targets.
> The kernel has patch 1/4 with your changes, plus patches 2/4, 3/4, and
> 4/4 as posted.

Ben, thanks for re-testing. And yes, I was wrong. Now I checked again
and finally remembered how it works.

So yes, symlink inode has data, and the target is in the data.

If we add an extattr to a symlink, we create a separate inode for that
xattr under the symlink inode. Any new xattr gets a new inode.

Artem.

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