Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 8 Jan 2018 07:53:44 -0500
From:      Baho Utot <baho-utot@columbus.rr.com>
To:        Aryeh Friedman <aryeh.friedman@gmail.com>
Cc:        FreeBSD Mailing List <freebsd-questions@freebsd.org>
Subject:   =?UTF-8?Q?Re:_Meltdown_=e2=80=93_Spectre?=
Message-ID:  <44279dcb-7b15-865a-ca71-938b3832d0e7@columbus.rr.com>
In-Reply-To: <CAGBxaXm=6NbZ+cz6WGB7YY7NT_+xOhdxb17ORTsQs5e7RvqKaQ@mail.gmail.com>
References:  <f9cc484e-be92-7aff-52fe-38655e85dbaa@columbus.rr.com> <CAH78cDqPnOUGoU=6x-BiugnpjmjYcd=CZS3fSNaX5tq-Uvma7g@mail.gmail.com> <bc9ad15b-a718-b901-76fa-bc43ce0c1f1a@columbus.rr.com> <3AECDC7F-8838-4C09-AC7F-117DFBAA326C@sigsegv.be> <20180108085756.GA3001@c720-r314251> <CAGBxaXnSRwtS=mbdsePyKvyZjTpu1tvo2O61SW60yQfdDJH4gA@mail.gmail.com> <48211515-cc6b-522b-ccd2-4d0c1f6a2072@columbus.rr.com> <CAGBxaXm=6NbZ+cz6WGB7YY7NT_+xOhdxb17ORTsQs5e7RvqKaQ@mail.gmail.com>

Next in thread | Previous in thread | Raw E-Mail | Index | Archive | Help


On 1/8/2018 7:37 AM, Aryeh Friedman wrote:
> 
> 
> On Mon, Jan 8, 2018 at 7:28 AM, Baho Utot <baho-utot@columbus.rr.com 
> <mailto:baho-utot@columbus.rr.com>> wrote:
> 
> 
> 
>     On 1/8/2018 4:15 AM, Aryeh Friedman wrote:
> 
>         On Mon, Jan 8, 2018 at 3:57 AM, Matthias Apitz <guru@unixarea.de
>         <mailto:guru@unixarea.de>> wrote:
> 
>             As I side note, and not related to FreeBSD: My Internet
>             server is run by
>             some webhosting company (www.1blu.de <http://www.1blu.de>),
>             they use Ubuntu servers and since
>             yesterday they have shutdown SSH access to the servers
>             argumenting that
>             they want
>             protect my (all's) servers against attacks of Meltdown and
>             Spectre.
> 
>             Imagine, next time we have to shutdown all IOT gadgets...
> 
> 
> 
>            Not always possible for things like medical test
>         equipment/devices.  For
>         example I maintain a specialized EMR for interacting with Dr.
>         prescribed
>         remote cardiac monitors.   Having those off line is not an
>         option since
>         they are used to detect if the patient needs something more
>         serious like a
>         pace maker (also almost always a IoT device these days) surgery.
> 
>         The actual monitoring is done on Windows and was attacked by some
>         ransomeware via a bit coin miner that somehow installed it
>         self.   Since
>         all the users claim that they don't read email/upload/download
>         executables
>         or any other of the known attack vectors this leaves something like
>         Meltdown or Spectre.   We have also detected issues on the
>         CentOS that has
>         the non-medical corporate site on it.   The only machine left on
>         touched on
>         the physical server (running some bare metal virtualization
>         tool) is the
>         FreeBSD machine that runs the actual EMR we wrote.
> 
>         TL;DR -- It seems Linux and Windows already have issues with
>         these holes
>         but I have seen little to no evidence that FreeBSD (when run as
>         a host).
>         In general when ever any virtualization issue (like the bleed
>         through on
>         Qemu last year) comes up FreeBSD is the one OS that seems to be
>         immune
>         (thanks to good design of the OS and bhyve).   This is the main
>         reason why
>         I chose FreeBSD over Linux as the reference host for PetiteCloud.
> 
> 
>     This is not operating system specific,  read the papers on theses
>     two. it attacks the cpu, usally through a JIT
> 
> 
> Please learn a little OS design theory before making insane claims.   
> Specifically it *ONLY* effects OS's that rely on the specific CPU 
> architecture (vs. a generic one).  Namely if you strictly partition the 
> page table between userland and kernel space (which xxxBSD has always 
> done and Linux has not) and don't use any CPU specific instructions to 
> do so (except for protected vs. unprotected mode in the original 386 
> design FreeBSD does not do this while yet again microslut and linux do).
> 
> For more info go read the more technical thread then here in -hackers@ 
> and -current@.


Go read the papers Spectre and Meltdown.
This attacks Intel and Arm processors, AMD processors seems to not have 
the issue.  Intel is issuing new firmware for their processors.
Why is does then Apple have the problem as well?

 From the papaer

Modern processors use branch prediction and speculative
execution to maximize performance. For example, if
the destination of a branch depends on a memory value
that is in the process of being read, CPUs will try guess
the destination and attempt to execute ahead. When the
memory value finally arrives, the CPU either discards or
commits the speculative computation. Speculative logic
is unfaithful in how it executes, can access to the victim’s
memory and registers, and can perform operations with
measurable side effects.
Spectre attacks involve inducing a victim to speculatively
perform operations that would not occur during
correct program execution and which leak the victim’s
confidential information via a side channel to the adversary.
This paper describes practical attacks that combine
methodology from side channel attacks, fault attacks,
and return-oriented programming that can read arbitrary
memory from the victim’s process. More broadly, the
paper shows that speculative execution implementations
violate the security assumptions underpinning numerous
software security mechanisms, including operating system
process separation, static analysis, containerization,
just-in-time (JIT) compilation, and countermeasures to
cache timing/side-channel attacks. These attacks represent
a serious threat to actual systems, since vulnerable
speculative execution capabilities are found in microprocessors
from Intel, AMD, and ARM that are used in billions
of devices.

And:

Abstract
The security of computer systems fundamentally relies
on memory isolation, e.g., kernel address ranges are
marked as non-accessible and are protected from user
access. In this paper, we present Meltdown. Meltdown
exploits side effects of out-of-order execution on modern
processors to read arbitrary kernel-memory locations
including personal data and passwords. Out-of-order
execution is an indispensable performance feature and
present in a wide range of modern processors. The attack
is independent of the operating system, and it does not
rely on any software vulnerabilities. Meltdown breaks
all security assumptions given by address space isolation
as well as paravirtualized environments and, thus,
every security mechanism building upon this foundation.
On affected systems, Meltdown enables an adversary to
read memory of other processes or virtual machines in
the cloud without any permissions or privileges, affecting
millions of customers and virtually every user of a
personal computer. We show that the KAISER defense
mechanism for KASLR [8] has the important (but inadvertent)
side effect of impeding Meltdown. We stress
that KAISER must be deployed immediately to prevent
large-scale exploitation of this severe information leakage.


One of the central security features of today’s operating
systems is memory isolation. Operating systems ensure
that user applications cannot access each other’s memories
and prevent user applications from reading or writing
kernel memory. This isolation is a cornerstone of our
computing environments and allows running multiple applications
on personal devices or executing processes of
multiple users on a single machine in the cloud.
On modern processors, the isolation between the kernel
and user processes is typically realized by a superviOne of the central 
security features of today’s operating
systems is memory isolation. Operating systems ensure
that user applications cannot access each other’s memories
and prevent user applications from reading or writing
kernel memory. This isolation is a cornerstone of our
computing environments and allows running multiple applications
on personal devices or executing processes of
multiple users on a single machine in the cloud.
On modern processors, the isolation between the kernel
and user processes is typically realized by a supervisor
bit of the processor that defines whether a memory
page of the kernel can be accessed or not. The basic
idea is that this bit can only be set when entering kernel
code and it is cleared when switching to user processes.
This hardware feature allows operating systems to map
the kernel into the address space of every process and
to have very efficient transitions from the user process
to the kernel, e.g., for interrupt handling. Consequently,
in practice, there is no change of the memory mapping
when switching from a user process to the kernel
novel attack that allows overcoming memory isolation
completely by providing a simple way for any user process
to read the entire kernel memory of the machine it
executes on, including all physical memory mapped in
the kernel region. Meltdown does not exploit any software
vulnerability, i.e., it works on all major operating
systems. Instead, Meltdown exploits side-channel information
available on most modern processors, e.g., modern
Intel microarchitectures since 2010 and potentially
on other CPUs of other vendors.

Notice:

Meltdown does not exploit any software vulnerability, i.e., it works on 
all major operating systems.

Your turn



Want to link to this message? Use this URL: <http://docs.FreeBSD.org/cgi/mid.cgi?44279dcb-7b15-865a-ca71-938b3832d0e7>