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Date:   Mon, 27 Jan 2020 15:19:59 -0800
From:   Kees Cook <keescook@chromium.org>
To:     Jiri Slaby <jslaby@suse.cz>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-kernel@vger.kernel.org, David Windsor <dave@nullcore.net>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-xfs@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        Christoph Lameter <cl@linux.com>,
        "David S. Miller" <davem@davemloft.net>,
        Laura Abbott <labbott@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Christoffer Dall <christoffer.dall@linaro.org>,
        Dave Kleikamp <dave.kleikamp@oracle.com>,
        Jan Kara <jack@suse.cz>,
        Luis de Bethencourt <luisbg@kernel.org>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Rik van Riel <riel@redhat.com>,
        Matthew Garrett <mjg59@google.com>,
        linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org,
        netdev@vger.kernel.org, kernel-hardening@lists.openwall.com,
        Vlastimil Babka <vbabka@suse.cz>,
        Michal Kubecek <mkubecek@suse.cz>
Subject: Re: [kernel-hardening] [PATCH 09/38] usercopy: Mark kmalloc caches
 as usercopy caches
Message-ID: <202001271519.AA6ADEACF0@keescook>
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 <201911121313.1097D6EE@keescook>
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On Thu, Jan 23, 2020 at 09:14:20AM +0100, Jiri Slaby wrote:
> On 14. 11. 19, 22:27, Kees Cook wrote:
> > On Tue, Nov 12, 2019 at 01:21:54PM -0800, Kees Cook wrote:
> >> How is iucv the only network protocol that has run into this? Do others
> >> use a bounce buffer?
> > 
> > Another solution would be to use a dedicated kmem cache (instead of the
> > shared kmalloc dma one)?
> 
> Has there been any conclusion to this thread yet? For the time being, we
> disabled HARDENED_USERCOPY on s390...
> 
> https://lore.kernel.org/kernel-hardening/9519edb7-456a-a2fa-659e-3e5a1ff89466@suse.cz/

I haven't heard anything new. What did people think of a separate kmem
cache?

-- 
Kees Cook