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

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On Thu, Mar 30, 2017 at 9:49 PM, Dmitry Monakhov <dmonakhov@openvz.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@openvz.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

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[PATCH 0/8] block: T10/DIF Fixes and cleanups Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 15:50 +0200
  [PATCH 2/8] bio-integrity: Do not allocate integrity context for bio w/o data Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
  [PATCH 3/8] bio-integrity: save original iterator for verify stage Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
  [PATCH 5/8] bio-integrity: fix interface for bio_integrity_trim Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
  [PATCH 6/8] bio-integrity: add bio_integrity_setup helper Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
    Re: [PATCH 6/8] bio-integrity: add bio_integrity_setup helper kbuild test robot <lkp@intel.com> - 2017-04-01 00:20 +0200
  [PATCH 4/8] bio-integrity: bio_trim should truncate integrity vector accordingly Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
  [PATCH 8/8] tcm_fileio: Prevent information leak for short reads Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
  [PATCH 7/8] T10: Move opencoded contants to common header Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
    Re: [PATCH 7/8] T10: Move opencoded contants to common header kbuild test robot <lkp@intel.com> - 2017-04-01 00:20 +0200
  [PATCH 1/8] Guard bvec iteration logic Dmitry Monakhov <dmonakhov@openvz.org> - 2017-03-30 16:00 +0200
    Re: [PATCH 1/8] Guard bvec iteration logic Ming Lei <tom.leiming@gmail.com> - 2017-03-31 10:30 +0200

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