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From: Kees Cook <keescook@chromium.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: linux-api@vger.kernel.org, kernel-hardening@lists.openwall.com,
	linux-x86_64@vger.kernel.org, linux-arch@vger.kernel.org,
	Andy Lutomirski <luto@kernel.org>,
	Carlos O'Donell <carlos@redhat.com>
Subject: Re: Detecting the availability of VSYSCALL
Date: Tue, 25 Jun 2019 13:08:07 -0700	[thread overview]
Message-ID: <201906251131.419D8ACB@keescook> (raw)
In-Reply-To: <87v9wty9v4.fsf@oldenburg2.str.redhat.com>

On Tue, Jun 25, 2019 at 05:15:27PM +0200, Florian Weimer wrote:
> Should we try mapping something at the magic address (without MAP_FIXED)
> and see if we get back a different address?  Something in the auxiliary
> vector would work for us, too, but nothing seems to exists there
> unfortunately.

It seems like mmap() won't even work because it's in the high memory
area. I can't map something a page under the vsyscall page either, so I
can't distinguish it with mmap, mprotect, madvise, or msync. :(

-- 
Kees Cook

  parent reply	other threads:[~2019-06-25 20:08 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-25 15:15 Detecting the availability of VSYSCALL Florian Weimer
2019-06-25 16:30 ` Thomas Gleixner
2019-06-25 16:38   ` Florian Weimer
2019-06-25 20:11     ` Andy Lutomirski
2019-06-25 20:47       ` Florian Weimer
2019-06-25 21:49         ` Andy Lutomirski
2019-06-26 12:12           ` Florian Weimer
2019-06-26 14:15             ` Andy Lutomirski
2019-06-26 15:00               ` Florian Weimer
2019-06-26 15:21                 ` Andy Lutomirski
2019-06-26 15:36                   ` Florian Weimer
2019-06-26 16:24                     ` Andy Lutomirski
2019-06-26 16:45                       ` Florian Weimer
2019-06-26 16:52                         ` Andy Lutomirski
2019-06-26 17:04                           ` Florian Weimer
2019-06-26 17:14                             ` Andy Lutomirski
2019-06-25 20:08 ` Kees Cook [this message]
2019-06-25 20:13   ` Andy Lutomirski

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