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  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]
Date:   Wed, 29 Jan 2020 16:43:30 +0000 (UTC)
From:   Christopher Lameter <>
To:     Kees Cook <>
cc:     Christian Borntraeger <>,
        Jiri Slaby <>,
        Julian Wiedmann <>,
        Ursula Braun <>,
        Alexander Viro <>,, David Windsor <>,
        Pekka Enberg <>,
        David Rientjes <>,
        Joonsoo Kim <>,
        Andrew Morton <>,,,
        Linus Torvalds <>,
        Andy Lutomirski <>,
        Christoph Hellwig <>,
        "David S. Miller" <>,
        Laura Abbott <>,
        Mark Rutland <>,
        "Martin K. Petersen" <>,
        Paolo Bonzini <>,
        Christoffer Dall <>,
        Dave Kleikamp <>,
        Jan Kara <>,
        Luis de Bethencourt <>,
        Marc Zyngier <>,
        Rik van Riel <>,
        Matthew Garrett <>,,,,,
        Vlastimil Babka <>,
        Michal Kubecek <>
Subject: Re: [kernel-hardening] [PATCH 09/38] usercopy: Mark kmalloc caches
 as usercopy caches

On Tue, 28 Jan 2020, Kees Cook wrote:

> > On the other hand not marking the DMA caches still seems questionable.
> My understanding is that exposing DMA memory to userspace copies can
> lead to unexpected results, especially for misbehaving hardware, so I'm
> not convinced this is a generically bad hardening choice.

"DMA" memory (and thus DMA caches) have nothing to do with DMA. Its a
legacy term. "DMA Memory" is memory limited to a certain
physical address boundary (old restrictions on certain devices only
supporting a limited number of address bits).

DMA can be done to NORMAL memory as well.

Powered by blists - more mailing lists