OpenBSD Journal

OpenBSD Journal

n2k18 Hackathon report: Ken Westerback (krw@) on disklabel(8) work, dhclient(8) progress

Contributed by Peter N. M. Hansteen on from the hackers on a train dept.

Fresh from the just concluded n2k18 hackathon comes this report from Ken Westerback (krw@), who writes:

How to travel from Dresden to Usti nad Labem for free!

No drama flying to Dresden, from which a train would take me to n2k18's home in Usti nad Labem. Other than being puzzled that it costs less to fly YYZ -> FRA -> DRS than it costs to fly YYZ -> FRA.

Read more…

OpenBSD Foundation gets first 2018 Iridium donation!

Contributed by rueda on from the tremor-of-77 dept.

Ken Westerback (krw@ when wearing his dev hat) wrote in with some great news:

The OpenBSD Foundation is excited to announce that it has received the first 2018 Iridium level donation. This year the first $100K+ donation came from Handshake (

We thank Handshake for its very generous support! This donation will no doubt fund many exciting projects in the coming years.

Congratulations to all concerned.

Of course, this donation does not preclude others from contributing ;-)

Disable SMT/Hyperthreading in all Intel BIOSes

Contributed by rueda on from the all-your-benchmarks-are-belong-to-us dept.

In a message to tech@, Theo de Raadt (deraadt@) gives an update on the state-of-play regarding processor vulnerabilities:

Two recently disclosed hardware bugs affected Intel cpus:

	 - TLBleed

	 - T1TF (the name "Foreshadow" refers to 1 of 3 aspects of this
	         bug, more aspects are surely on the way)

Solving these bugs requires new cpu microcode, a coding workaround,
*AND* the disabling of SMT / Hyperthreading.

Read more…

Fix for L1TF issue in Intel CPUs committed

Contributed by Paul 'WEiRD' de Weerd on from the cached bugs dept.

Theo de Raadt (deraadt@) has committed a diff to mitigate the "Intel L1TF screwup" for the amd64 platform we reported on earlier:

From: Theo de Raadt (elided)
Date: Tue, 21 Aug 2018 13:04:41 -0600 (MDT)
Subject: CVS: src

CVSROOT:        /cvs
Module name:    src
Changes by: 2018/08/21 13:04:41

Modified files:
        sys/arch/amd64/amd64: identcpu.c vmm.c vmm_support.S 
        sys/arch/amd64/include: cpu.h specialreg.h vmmvar.h 

Log message:
Perform mitigations for Intel L1TF screwup.  There are three options:
(1) Future cpus which don't have the bug, (2) cpu's with microcode
containing a L1D flush operation, (3) stuffing the L1D cache with fresh
data and expiring old content.  This stuffing loop is complicated and
interesting, no details on the mitigation have been released by Intel so
Mike and I studied other systems for inspiration.  Replacement algorithm
for the L1D is described in the tlbleed paper. We use a 64K PA-linear
region filled with trapsleds (in case there is L1D->L1I data movement).
The TLBs covering the region are loaded first, because TLB loading
apparently flows through the D cache.  Before performing vmlaunch or
vmresume, the cachelines covering the guest registers are also flushed.
with mlarkin, additional testing by pd, handy comments from the
kettenis and guenther peanuts

Now we wait for further discoveries…

Theo on the latest Intel issues

Contributed by Paul 'WEiRD' de Weerd on from the the gift that keeps on giving dept.

Theo de Raadt (deraadt@) posted to the tech@ mailing list with some background on how the latest discovered Intel CPU issues relate to OpenBSD.

Date: Wed, 15 Aug 2018 00:31:16 -0600
From: Theo de Raadt [elided]
Subject: CVE-2018-3615, CVE-2018-3620, CVE-2018-3646

These 3 issues all relate to a bug in Intel cpus

The cpu will speculatively honour invalid PTE against data in the
on-core L1 cache.  Memory disclosure occurs into the wrong context.

These 3 issues (CVE-2018-3615, CVE-2018-3620, CVE-2018-3646) together
are the currently public artifacts of this one bug.

Read more…


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Copyright © - Daniel Hartmeier. All rights reserved. Articles and comments are copyright their respective authors, submission implies license to publish on this web site. Contents of the archive prior to as well as images and HTML templates were copied from the fabulous original with Jose's and Jim's kind permission. This journal runs as CGI with httpd(8) on OpenBSD, the source code is BSD licensed. undeadly \Un*dead"ly\, a. Not subject to death; immortal. [Obs.]