From: Borislav Petkov <bp@suse.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: yalin wang <yalin.wang2010@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
mingo@redhat.com, x86@kernel.org,
open list <linux-kernel@vger.kernel.org>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [x86] copy_from{to}_user question
Date: Sat, 22 Aug 2015 11:05:19 +0200 [thread overview]
Message-ID: <20150822090519.GA2812@nazgul.tnic> (raw)
In-Reply-To: <55D792C8.6090006@zytor.com>
On Fri, Aug 21, 2015 at 02:06:16PM -0700, H. Peter Anvin wrote:
> What I'm saying is that we do do STAC, which *disables* SMAP. We have
> to do that because one pointer is known to be a user space pointer.
>
> However, we currently don't verify that the *other* pointer is kernel
> space, which it is supposed to be (if not, we should be using
> copy_in_user). We have to do this manually since we have to STAC which
> means SMAP doesn't do anything at all. I believe it would be a good
> idea to add such checks (and they would even benefit non-SMAP hardware.)
Ah, ok, so we're on the same page.
And yep, Linus gave the probe_kernel_read() suggestion in another mail.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
next prev parent reply other threads:[~2015-08-22 9:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-12 9:01 [x86] copy_from{to}_user question yalin wang
2015-08-12 10:07 ` Borislav Petkov
2015-08-13 10:04 ` yalin wang
2015-08-13 16:43 ` Borislav Petkov
2015-08-17 3:27 ` yalin wang
2015-08-17 4:16 ` Borislav Petkov
2015-08-20 8:58 ` yalin wang
2015-08-20 18:22 ` H. Peter Anvin
2015-08-21 4:35 ` Borislav Petkov
2015-08-21 21:06 ` H. Peter Anvin
2015-08-22 9:05 ` Borislav Petkov [this message]
2015-08-24 7:52 ` yalin wang
2015-08-24 12:05 ` Jeff Epler
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