linux-kernel - Re: [PATCH] mm, hugetlb: correct bit shift in hstate

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: <20141022114437.72eb61ce3e2348c52ab3d1db@linux-foundation.org>
Date:	Wed, 22 Oct 2014 11:44:37 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Andrey Ryabinin <a.ryabinin@...sung.com>
Cc:	Sasha Levin <sasha.levin@...cle.com>, n-horiguchi@...jp.nec.com,
	aarcange@...hat.com, mgorman@...e.de, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: Re: [PATCH] mm, hugetlb: correct bit shift in hstate_sizelog

On Wed, 22 Oct 2014 09:42:46 +0400 Andrey Ryabinin <a.ryabinin@...sung.com> wrote:

> On 10/21/2014 10:15 PM, Sasha Levin wrote:
> > hstate_sizelog() would shift left an int rather than long, triggering
> > undefined behaviour and passing an incorrect value when the requested
> > page size was more than 4GB, thus breaking >4GB pages.
> 
> > 
> > Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
> > ---
> >  include/linux/hugetlb.h |    3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> > index 65e12a2..57e0dfd 100644
> > --- a/include/linux/hugetlb.h
> > +++ b/include/linux/hugetlb.h
> > @@ -312,7 +312,8 @@ static inline struct hstate *hstate_sizelog(int page_size_log)
> >  {
> >  	if (!page_size_log)
> >  		return &default_hstate;
> > -	return size_to_hstate(1 << page_size_log);
> > +
> > +	return size_to_hstate(1UL << page_size_log);
> 
> That still could be undefined on 32-bits. Either use 1ULL or reduce SHM_HUGE_MASK on 32bits.
> 

But

struct hstate *size_to_hstate(unsigned long size)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/