netdev - Re: [kernel-hardening] Re: [PATCH v3 03/31] usercopy: Mark kmalloc caches as usercopy caches

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: <alpine.DEB.2.20.1709211102320.14742@nuc-kabylake>
Date:   Thu, 21 Sep 2017 11:04:35 -0500 (CDT)
From:   Christopher Lameter <cl@...ux.com>
To:     Kees Cook <keescook@...omium.org>
cc:     LKML <linux-kernel@...r.kernel.org>,
        David Windsor <dave@...lcore.net>,
        Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linux-MM <linux-mm@...ck.org>, linux-xfs@...r.kernel.org,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        Network Development <netdev@...r.kernel.org>,
        "kernel-hardening@...ts.openwall.com" 
        <kernel-hardening@...ts.openwall.com>
Subject: Re: [kernel-hardening] Re: [PATCH v3 03/31] usercopy: Mark kmalloc
 caches as usercopy caches

On Thu, 21 Sep 2017, Kees Cook wrote:

> > So what is the point of this patch?
>
> The DMA kmalloc caches are not whitelisted:

The DMA kmalloc caches are pretty obsolete and mostly there for obscure
drivers.

??

> >>                         kmalloc_dma_caches[i] = create_kmalloc_cache(n,
> >> -                               size, SLAB_CACHE_DMA | flags);
> >> +                               size, SLAB_CACHE_DMA | flags, 0, 0);
>
> So this is creating the distinction between the kmallocs that go to
> userspace and those that don't. The expectation is that future work
> can start to distinguish between "for userspace" and "only kernel"
> kmalloc allocations, as is already done here for DMA.

The creation of the kmalloc caches in earlier patches already setup the
"whitelisting". Why do it twice?