Re: Endless getdents() in vfat filesystem

From	Richard Weinberger <richard@nod.at>
Newsgroups	linux.kernel
Subject	Re: Endless getdents() in vfat filesystem
Date	2015-11-15 12:30 +0100
Message-ID	<qv3Fn-HW-3@gated-at.bofh.it> (permalink)
References	(2 earlier) <quIrf-42Y-5@gated-at.bofh.it> <quKt4-5k2-3@gated-at.bofh.it> <quKCJ-5Cl-5@gated-at.bofh.it> <quNAC-7sG-19@gated-at.bofh.it> <qv3m1-zv-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Am 15.11.2015 um 12:05 schrieb Vegard Nossum:
> On 11/14/2015 07:19 PM, OGAWA Hirofumi wrote:
>> Richard Weinberger <richard@nod.at> writes:
>>
>>>>> Yes, it does fixes the problem here, but I can't really comment on the
>>>>> correctness of the patch.
>>>>>
>>>>> Thanks for the quick reponse,
>>>>
>>>> I made cleanup and made sure fake_offset is corrected.
>>>>
>>>> Richard, Signed-off-by was missed in your patch, so I added. Can you
>>>> agree to Signed-off-by?
>>>
>>> Sure!
>>
>> Attached updated patch made smaller changes, and with missed Cc: stable.
>>
>> Andrew, please queue this up.
>>
>> Thanks.
>>
> 
> It would be nice to have a proper patch description too. How about this?
> 
> """
> For the root directory, . and .. are faked (using dir_emit_dots()) and
> ctx->pos is reset from 2 to 0.
> 
> A corrupted root directory could cause fat_get_entry() to fail, but
> ->iterate() (fat_readdir()) reports progress to the VFS (with ctx->pos
> rewound to 0), so any following calls to ->iterate() continue to return
> the same entries again and again.
> 
> The result is that userspace will never see the end of the directory,
> causing e.g. 'ls' to hang in a getdents() loop.
> """

Agreed. And you deserve also a Reported-and-tested-by. :-)

Thanks,
//richard
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Thread

Endless getdents() in vfat filesystem Vegard Nossum <vegard.nossum@oracle.com> - 2015-11-14 02:30 +0100
  Re: Endless getdents() in vfat filesystem Richard Weinberger <richard.weinberger@gmail.com> - 2015-11-14 11:40 +0100
    Re: Endless getdents() in vfat filesystem Vegard Nossum <vegard.nossum@oracle.com> - 2015-11-14 13:50 +0100
      Re: Endless getdents() in vfat filesystem OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> - 2015-11-14 16:00 +0100
        Re: Endless getdents() in vfat filesystem Richard Weinberger <richard@nod.at> - 2015-11-14 16:10 +0100
          Re: Endless getdents() in vfat filesystem OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> - 2015-11-14 19:20 +0100
            Re: Endless getdents() in vfat filesystem Vegard Nossum <vegard.nossum@oracle.com> - 2015-11-15 12:10 +0100
              Re: Endless getdents() in vfat filesystem Richard Weinberger <richard@nod.at> - 2015-11-15 12:30 +0100
                Re: Endless getdents() in vfat filesystem OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> - 2015-11-15 14:00 +0100

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