From: Eric Biggers <ebiggers@kernel.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: "OGAWA Hirofumi" <hirofumi@mail.parknet.co.jp>,
"Pali Rohár" <pali.rohar@gmail.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
"Theodore Y. Ts'o" <tytso@mit.edu>,
"Namjae Jeon" <linkinjeon@gmail.com>,
"Gabriel Krisman Bertazi" <krisman@collabora.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: oopsably broken case-insensitive support in ext4 and f2fs (Re: vfat: Broken case-insensitive support for UTF-8)
Date: Thu, 23 Jan 2020 20:29:53 -0800 [thread overview]
Message-ID: <20200124042953.GA832@sol.localdomain> (raw)
In-Reply-To: <20200120193558.GD8904@ZenIV.linux.org.uk>
On Mon, Jan 20, 2020 at 07:35:58PM +0000, Al Viro wrote:
> On Mon, Jan 20, 2020 at 08:07:21AM +0000, Al Viro wrote:
>
> > > > I hadn't checked ->d_compare() instances for a while; somebody needs to
> > > > do that again, by the look of it. The above definitely is broken;
> > > > no idea how many other instaces had grown such bugs...
> > >
> > > f2fs one also has the same bug. Anyway, I'm going down right now, will
> > > check the rest tomorrow morning...
> >
> > We _probably_ can get away with just checking that inode for NULL and
> > buggering off if it is (->d_seq mismatch is guaranteed in that case),
> > but I suspect that we might need READ_ONCE() on both dereferences.
> > I hate memory barriers...
>
> FWIW, other instances seem to be OK; HFS+ one might or might not be
> OK in the face of concurrent rename (wrong result in that case is
> no problem; oops would be), but it doesn't play silly buggers with
> pointer-chasing.
>
> ext4 and f2fs do, and ->d_compare() is broken in both of them.
Thanks Al. I sent out fixes for this:
ext4: https://lore.kernel.org/r/20200124041234.159740-1-ebiggers@kernel.org
f2fs: https://lore.kernel.org/r/20200124041549.159983-1-ebiggers@kernel.org
Note that ->d_hash() was broken too. In fact, that was much easier to
reproduce.
- Eric
next prev parent reply other threads:[~2020-01-24 4:30 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-19 22:14 vfat: Broken case-insensitive support for UTF-8 Pali Rohár
2020-01-19 23:08 ` Al Viro
2020-01-19 23:33 ` Pali Rohár
2020-01-20 0:09 ` Al Viro
2020-01-20 11:19 ` Pali Rohár
2020-01-20 4:04 ` OGAWA Hirofumi
2020-01-20 7:30 ` Al Viro
2020-01-20 7:45 ` Al Viro
2020-01-20 8:07 ` oopsably broken case-insensitive support in ext4 and f2fs (Re: vfat: Broken case-insensitive support for UTF-8) Al Viro
2020-01-20 19:35 ` Al Viro
2020-01-24 4:29 ` Eric Biggers [this message]
2020-01-24 17:47 ` Linus Torvalds
2020-01-24 18:03 ` Jaegeuk Kim
2020-01-24 18:45 ` Eric Biggers
2020-01-20 11:04 ` vfat: Broken case-insensitive support for UTF-8 Pali Rohár
2020-01-20 12:07 ` OGAWA Hirofumi
2020-01-20 21:40 ` Pali Rohár
2020-01-20 22:46 ` Al Viro
2020-01-20 23:57 ` Pali Rohár
2020-01-21 0:07 ` Al Viro
2020-01-21 20:34 ` Pali Rohár
2020-01-21 21:36 ` Al Viro
2020-01-21 22:14 ` Al Viro
2020-01-21 22:46 ` Pali Rohár
2020-01-26 23:08 ` Pali Rohár
2020-01-21 12:43 ` David Laight
2020-01-22 0:25 ` Gabriel Krisman Bertazi
2020-01-20 15:07 ` David Laight
2020-01-20 15:20 ` Pali Rohár
2020-01-20 15:47 ` David Laight
2020-01-20 16:12 ` Al Viro
2020-01-20 16:51 ` David Laight
2020-01-20 16:27 ` Pali Rohár
2020-01-20 16:43 ` David Laight
2020-01-20 16:56 ` Pali Rohár
2020-01-20 17:37 ` Theodore Y. Ts'o
2020-01-20 17:32 ` Theodore Y. Ts'o
2020-01-20 17:56 ` Pali Rohár
2020-01-21 3:52 ` OGAWA Hirofumi
2020-01-21 11:00 ` Pali Rohár
2020-01-21 12:26 ` OGAWA Hirofumi
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