linux-kernel - Re: [PATCH 1/8] Guard bvec iteration logic

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: <CACVXFVPNpZgo4-Hjbg0_BN2Xby-P4R_zcWTR_MDN_v+8TGM3sw@mail.gmail.com>
Date:   Fri, 31 Mar 2017 16:21:40 +0800
From:   Ming Lei <tom.leiming@...il.com>
To:     Dmitry Monakhov <dmonakhov@...nvz.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-block <linux-block@...r.kernel.org>,
        "Martin K. Petersen" <martin.petersen@...cle.com>
Subject: Re: [PATCH 1/8] Guard bvec iteration logic

On Thu, Mar 30, 2017 at 9:49 PM, Dmitry Monakhov <dmonakhov@...nvz.org> wrote:
> If some one try to attempt advance bvec beyond it's size we simply
> dump WARN_ONCE and continue to iterate beyond bvec array boundaries.
> This simply means that we endup dereferencing/corrupting random memory
> region.
>
> Code was added long time ago here 4550dd6c, luckily no one hit it
> in real life :)
>
> Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
> ---
>  include/linux/bvec.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/linux/bvec.h b/include/linux/bvec.h
> index 89b65b8..86b914f 100644
> --- a/include/linux/bvec.h
> +++ b/include/linux/bvec.h
> @@ -70,8 +70,7 @@ static inline void bvec_iter_advance(const struct bio_vec *bv,
>                                      struct bvec_iter *iter,
>                                      unsigned bytes)
>  {
> -       WARN_ONCE(bytes > iter->bi_size,
> -                 "Attempted to advance past end of bvec iter\n");
> +       BUG_ON(bytes > iter->bi_size);

This may not a good idea, especially Linus did not like BUG_ON(), please see the
following link:

https://lkml.org/lkml/2016/10/4/1



Thanks,
Ming Lei