Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Content-Type: text/plain;
        charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.1\))
Subject: Re: [syzbot] [hfs?] WARNING in hfs_write_inode
From:   Viacheslav Dubeyko <slava@dubeyko.com>
In-Reply-To: <ab7a9477-ddc7-430f-b4ee-c67251e879b0@app.fastmail.com>
Date:   Wed, 4 Jan 2023 16:36:51 -0800
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        syzbot <syzbot+7bb7cd3595533513a9e7@syzkaller.appspotmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        christian.brauner@ubuntu.com,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Jeff Layton <jlayton@kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com,
        Matthew Wilcox <willy@infradead.org>,
        ZhangPeng <zhangpeng362@huawei.com>,
        linux-m68k@lists.linux-m68k.org
Content-Transfer-Encoding: quoted-printable
Message-Id: <2575F983-D170-4B79-A6BA-912D4ED2CC73@dubeyko.com>
References: <000000000000dbce4e05f170f289@google.com>
 <5f45bb9a-5e00-48dd-82b0-46b19b1b98a3@app.fastmail.com>
 <CAHk-=wi8XyAUF9_z6-oa4Ava6PVZeE-=TVNcFK1puQHpOtqLLw@mail.gmail.com>
 <ab7a9477-ddc7-430f-b4ee-c67251e879b0@app.fastmail.com>
To:     Arnd Bergmann <arnd@arndb.de>
Precedence: bulk

Hi Arnd,

> On Jan 4, 2023, at 2:33 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>=20
> On Wed, Jan 4, 2023, at 20:06, Linus Torvalds wrote:
>>=20
>> I suspect this code is basically all dead. =46rom what I can tell, =
hfs
>> only gets updates for
>>=20
>> (a) syzbot reports
>>=20
>> (b) vfs interface changes
>=20
> There is clearly no new work going into it, and most data exchange
> with MacOS would use HFS+, but I think there are still some users.
>=20
>> and the last real changes seem to have been by Ernesto A. Fern=C3=A1nde=
z
>> back in 2018.
>>=20
>> Hmm. Looking at that code, we have another bug in there, introduced =
by
>> an earlier fix for a similar issue: commit 8d824e69d9f3 ("hfs: fix =
OOB
>> Read in __hfs_brec_find") added
>>=20
>> +       if (HFS_I(main_inode)->cat_key.CName.len > HFS_NAMELEN)
>> +               return -EIO;
>>=20
>> but it's after hfs_find_init(), so it should actually have done a
>> hfs_find_exit() to not leak memory.
>>=20
>> So we should probably fix that too.
>>=20
>> Something like this ENTIRELY UNTESTED patch?
>>=20
>> Do we have anybody who looks at hfs?
>=20
> Adding Viacheslav Dubeyko to Cc, he's at least been reviewing
> patches for HFS and HFS+ somewhat recently. The linux-m68k
> list may have some users dual-booting old MacOS.
>=20
> Viacheslav, see the start of the thread at
> https://lore.kernel.org/lkml/000000000000dbce4e05f170f289@google.com/
>=20

Let me take a look into the issue.

Thanks,
Slava.