linux-kernel - Re: [PATCH] mm: Make kvmalloc refuse to allocate more than 2GB

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] [day] [month] [year] [list]

Date:   Tue, 27 Jul 2021 09:38:17 +0200
From:   Michal Hocko <mhocko@...e.com>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     Al Viro <viro@...iv.linux.org.uk>,
        Qualys Security Advisory <qsa@...lys.com>,
        Eric Sandeen <sandeen@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: Make kvmalloc refuse to allocate more than 2GB

On Wed 21-07-21 19:41:31, Matthew Wilcox wrote:
> It's generally dangerous to allocate such large quantities of memory
> within the kernel owing to our propensity to use 'int' to represent
> a length.  If somebody really needs it, we can add a kvmalloc_large()
> later, but let's default to "You can't allocate that much memory".

I do agree that limiting kvmalloc allocation size is a reasonable thing
to do but I do not really see why we should remove the check from
seq_buf_alloc. Implicitly relying on kvmalloc to workaround a bug that
was in seq_buf code seems like a step backwards to me.
-- 
Michal Hocko
SUSE Labs