linux-kernel - Re: [PATCH] UBI: Fix crash in try_recover

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAMuHMdVJJxN2bU6JVsia9uDMonczqMw3SiAu-eygnHVLUqcqMg@mail.gmail.com>
Date:   Mon, 17 Oct 2016 10:00:25 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Boris Brezillon <boris.brezillon@...e-electrons.com>
Cc:     Richard Weinberger <richard@....at>,
        Brian Norris <computersforpeace@...il.com>,
        Artem Bityutskiy <dedekind1@...il.com>,
        David Woodhouse <dwmw2@...radead.org>,
        MTD Maling List <linux-mtd@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] UBI: Fix crash in try_recover_peb()

Hi Boris,

On Thu, Oct 13, 2016 at 4:24 PM, Boris Brezillon
<boris.brezillon@...e-electrons.com> wrote:
> On Thu, 13 Oct 2016 16:05:36 +0200
> Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>
>>     drivers/mtd/ubi/eba.c: In function ‘try_recover_peb’:
>>     drivers/mtd/ubi/eba.c:744: warning: ‘vid_hdr’ is used uninitialized in this function
>>
>> The pointer vid_hdr is indeed not initialized, leading to a crash when
>> it is dereferenced.
>>
>> Fix this by obtaining the pointer from the VID buffer, like is done
>> everywhere else.
>
> Indeed, I don't know how I missed that one :-/.
>
>>
>> Fixes: 3291b52f9ff0acc8 ("UBI: introduce the VID buffer concept")
>> Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
>
> One minor comment below, otherwise
>
> Reviewed-by: Boris Brezillon <boris.brezillon@...e-electrons.com>

Thanks!

>> ---
>> Completely untested. And I know nothing about UBI ;-)
>> ---
>>  drivers/mtd/ubi/eba.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
>> index 95c4048a371e87b6..388e46be6ad92805 100644
>> --- a/drivers/mtd/ubi/eba.c
>> +++ b/drivers/mtd/ubi/eba.c
>> @@ -741,6 +741,7 @@ static int try_recover_peb(struct ubi_volume *vol, int pnum, int lnum,
>>               goto out_put;
>>       }
>>
>> +     vid_hdr = ubi_get_vid_hdr(vidb);
>
> Can you move this assignment at variable declaration time?

I can do that. However, that moves the call to ubi_get_vid_hdr() _before_
the call to ubi_io_read_vid_hdr().

While that would still work (ubi_get_vid_hdr() would just return a pointer to
the not-yet-read data), I think it's better to not move it, to prevent people
from accidentally trying to use it before the data has been read.

Do you agree?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds