Tag: Linux

Linux Foundation workstation security ebook

~ hucktech ~ Leave a comment

[…]Now, before you even start with your operating system installation, there are a few things you should consider to ensure your pre-boot environment is up to snuff. You will want to make sure:
* UEFI boot mode is used (not legacy BIOS) (ESSENTIAL)
* A password is required to enter UEFI configuration (ESSENTIAL)
* SecureBoot is enabled (ESSENTIAL)
* A UEFI-level password is required to boot the system (NICE-to-HAVE)

https://www.linux.com/news/linux-workstation-security/2017/3/4-security-steps-take-you-install-linux

http://go.linuxfoundation.org/workstation_security_ebook

Sounds interesting, but I don’t see any actual download link for this ebook. I guess I need some sleep.

There is also this: https://firmwaresecurity.com/2015/08/31/linux-foundation-it-security-policies-firmware-guidance/

 

Linux Kernel Podcast returns

~ hucktech ~ Leave a comment

After being offine since 2009, the Linux Kernel podcast has restarted. The first new episode mentions an EFI/ACPI patch!

Bhupesh Sharma posted a patch moving in-kernel handling of ACPI BGRT (Boot(time) Graphics Resource) tables out of the x86 architecture tree and into drivers/firmware/efi (so that it can be shared with the 64-bit ARM Architecture).

http://www.kernelpodcast.org/2017/02/20/kernel-podcast-for-feb-20th-2017/

Linux Kernel Podcast

http://jcm.libsyn.com/rss

SUSE on UEFI -vs- BIOS

~ hucktech ~ Leave a comment

I missed this blog post from SuSE from last year:

[…]One UEFI topic that I noticeably did not address in this blog is secure boot. This was actually covered extensively in three previous blogs. To read those blogs do a search for “Secure Boot” at suse.com. I also did not address the comparison of UEFI and BIOS from the operating systems perspective in this blog. That is a separate blog that was released at the same time as this one (Comparison of UEFI and BIOS – from an operating system perspective). Please read it too. Hopefully this gives you some helpful information about the transition from BIOS to UEFI, on the hardware side. You can find more information about SUSE YES Certification at https://www.suse.com/partners/ihv/yes/ or search for YES CERTIFIED hardware at https://www.suse.com/yessearch/. You can also review previous YES Certification blogs at YES Certification blog post[…]

https://www.suse.com/communities/blog/comparison-uefi-bios-hardware-perspective/

more on SCONE

~ hucktech ~ Leave a comment

Re: SCONE, mentioned here: https://firmwaresecurity.com/2017/01/07/secure-linux-containers-with-intel-sgx/

 

SCONE: Secure Linux Containers with Intel SGX
Sergei Arnautov, Bohdan Trach, Franz Gregor, Thomas Knauth, Andre Martin, Christian Priebe, Joshua Lind, Divya Muthukumaran, Dan O’Keeffe, Mark L Stillwell, David Goltzsche, Dave Eyers, Rüdiger Kapitza, Peter Pietzuch, Christof Fetzer

In multi-tenant environments, Linux containers managed by Docker or Kubernetes have a lower resource footprint, faster startup times, and higher I/O performance compared to virtual machines (VMs) on hypervisors. Yet their weaker isolation guarantees, enforced through software kernel mechanisms, make it easier for attackers to compromise the confidentiality and integrity of application data within containers. We describe SCONE, a secure container mechanism for Docker that uses the SGX trusted execution support of Intel CPUs to protect container processes from outside attacks. The design of SCONE leads to (i) a small trusted computing base (TCB) and (ii) a low performance overhead: SCONE offers a secure C standard library interface that transparently encrypts/decrypts I/O data; to reduce the performance impact of thread synchronization and system calls within SGX enclaves, SCONE supports user-level threading and asynchronous system calls. Our evaluation shows that it protects unmodified applications with SGX, achieving 0.6✓–1.2✓ of native throughput.[…]

https://www.usenix.org/conference/osdi16/technical-sessions/presentation/arnautov

Click to access osdi16-arnautov.pdf

Click to access osdi16_slides_knauth.pdf

Linux Container hardening

~ hucktech ~ Leave a comment

https://twitter.com/jessfraz/status/827500850691969024

Mission Statement: This project will focus on hardening of Linux containers. It will help contribute patches to the Kernel Self Protection Project that evolve the primitives in the Linux kernel used by containers (namespaces, cgroups, etc) to be more secure. This will include brainstorming, designing and implementing ways to future proof namespaces et all in the kernel. This will benefit all container runtimes by keeping the focus on improving the kernel in the subsystems used by containers. We will strive to push the entire container ecosystem to be more secure by fixing the ground they are built upon. Much like the Kernel Self Protection Project we think of security beyond fixing bugs. Fixing bugs is important and we will do that as well but the main value will come from finding ways to future proof namespaces with features that will eliminate undisclosed vulnerabilities. At this point, it is no longer enough to try to fix all the bugs within namespaces, we must try to find ways to make them more secure from the very foundation. We will also work to help educate people on how to use the features of Capabilities, Seccomp, AppArmor, and SELinux to harden their containers. We will try to find ways to make them more accessible to more users.

https://containerhardening.org/

ACPI graph support

~ hucktech ~ Leave a comment

Sakari Ailus of Intel posted a patch to the Linux-ACPI list that enables ‘ACPI graph support’. Slightly edited version of announcement below:

I posted a previous RFC labelled set of ACPI graph support a while ago[1]. Since then, the matter of how the properties should be used as in ACPI _DSD was discussed in Ksummit and LPC, and a document detailing the rules  was written [1]. I’ve additionally posted v1 which can be found here[2]. This set contains patches written by Mika Westerberg and by myself. The patchset brings support for graphs to ACPI. The functionality achieved by these patches is very similar to what the Device tree provides: the port and the endpoint concept are being employed. The patches make use of the _DSD property and data extensions to achieve this. The fwnode interface is extended by graph functionality; this way graph information originating from both OF and ACPI may be accessed using the same interface, without being aware of the underlying firmware interface. The last patch of the set contains ASL documentation including an example. The entire set may also be found here (on mediatree.git master, but it also applies cleanly on linux-next)[3]. The resulting fwnode graph interface has been tested using V4L2 async with fwnode matching and smiapp and omap3isp drivers, with appropriate changes to make use of the fwnode interface in drivers. The V4L2 patches can be found here. The fwnode graph interface is used by the newly added V4L2 fwnode framework which replaces the V4L2 OF framework, with equivalent functionality.[4]

[1] http://www.spinics.net/lists/linux-acpi/msg69547.html
[2] http://www.spinics.net/lists/linux-acpi/msg71661.html
[3] https://git.linuxtv.org/sailus/media_tree.git/log/?h=acpi-graph
[4] https://git.linuxtv.org/sailus/media_tree.git/log/?h=v4l2-acpi

Full announcement — including changes for v1 — is on the linux-acpi list:
http://vger.kernel.org/majordomo-info.html
http://www.spinics.net/lists/linux-acpi/

LUV gets telemetrics

~ hucktech ~ Leave a comment

Megha Dey of Intel just submitted a 4-part patch to LUV, adding telemetrics. Below is slightly-edited comments from patch, some build instructions omitted. For full text see email, URL at end.

[Luv] [PATCH V1 0/4] Introduce telemetrics feature in LUV

This patchset consists of all the patches needed to enable the telemetrics feature in LUV. LUV brings together multiple separate upstream test suites into a cohesive and easy-to-use product and validates UEFI firmware at critical levels of the software stack. It may be possible that one of the test suites crashes while running. It may be even possible that a kernel panic is observed. Under these scenarios, it would be useful for LUV to call home and submit forensic data to analyze and address the problem. The telemetrics feature will do just this.  Of course, this will be an opt-in feature(command line argument telemetrics.opt-in) and users will get clear indication that data is being collected. We have used the telemetrics-client code developed by the clear-linux team and tried to incorporate it in LUV. It has support for crashprobe (invoked whenever a core dump is created), oopsprobe(invoked when there is a kernel oops observed) and pstore-probe(invoked when there is a kernel panic and system reboots). In any of these scenarios, telemetrics records will be sent to the server, currently residing at(one used by clear linux):
 http://rnesius-tmdev.jf.intel.com/telemetryui/
The build ID 122122 can be used to filter the LUV telemetrics records which can be further analysed. In due course, we will have to implement a server of our own to handle this. For telemetrics to work in LUV, the following changes were needed:

1. Migrate to SystemD: LUV currently uses the SystemV init manager but since telemetrics-client repo and the latest yocto have updated on to SystemD, LUV also needs to migrate to SystemD. Since Systemd will not work with the existing psplash graphical manager, we have disabled the splash screen

2.    Migrate to Plymouth: LUV currently uses the psplash graphical manager, but since SystemD is compatible with only Plymouth graphical manager, we have migrated to Plymouth. PLEASE NOTE: Before migrating to plymouth, we have to merge the morty branch of the meta-oe layer provided by open embedded into the LUV repo and add the meta-oe layer to the build/conf/bblayers.conf file. Here are the steps to do this: <omitted> The loglevel has been set to 0 else there are lots of kernel messages overwriting the plymouth screen. Hence, details about the individual tests in the testsuites will not appear when the splash screen is set to false when using plymouth. If the user wants the test details to be shown, they would have to remove the ‘quiet’ and ‘loglevel=0’ kernel command line parameters.

3. Enable networking: After shifting to systemD, the LUV image is not being assigned an IP on boot. This is because it is still using a systemV startup script to do the same. Since systemD names its interfaces differently, we could not see any interfaces with a valid IP. This patch adds the networkd package, introduces a network config file which starts dhcp by default for all interfaces whose names start with en(pci devices which get renamed by udev) or eth(backward compatible) and a service file (networking.service) which will bring up the network and make sure an IP is assigned during boot. It refers:
    https://wiki.archlinux.org/index.php/systemd-networkd

4. Enable telemetrics in LUV: A yocto recipe which fetches the clear-linux telemetrics-client repo, builds it and installs all the necessary service files, daemons and probes has been added. Also, Add a kernel line parameter which lets the user opt-in to the telemetrics feature (telemetrics.opt-in). By default, this feature is disabled. Currently, the telemetrics records can be found here: http://rnesius-tmdev.jf.intel.com/telemetryui/

Full announcement and patch:
https://lists.01.org/mailman/listinfo/luv

Jan Lübbe on eLinux security

~ hucktech ~ Leave a comment

Jan Lübbe of Pengutronix e.K. gave a talk at ELCE’16 (Embedded Linux Conference Europe 2016) called: “Long-Term Maintenance, or How to (Mis-)Manage Embedded Systems for 10+ Years”.

“Hardware vendors don’t care about security or maintenance.”

https://www.linux.com/news/event/ELCE/2017/long-term-embedded-linux-maintenance-made-easier

Keeping Linux devices secure with rigorous long-term maintenance


http://elinux.org/ELC_Europe_2016_Presentations

Click to access Long-Term_Maintenance.pdf

FWTS 17.01.00 released

~ hucktech ~ Leave a comment

Alex Hung of Canonical has announced the release of FWTS 17.01.00, the FirmWare Test Suite.

New Features:
* ACPICA: Update to version 20161222
* klog.json: Add kernel errors to the database
* fedora/fwts.spec: Add initial version of fwts.spec
* fedora/buildrpm.sh: Add build script for RPMs

See the full announcement for more details:
http://fwts.ubuntu.com/release/fwts-V17.01.00.tar.gz
https://launchpad.net/~firmware-testing-team/+archive/ubuntu/ppa-fwts-stable
https://wiki.ubuntu.com/FirmwareTestSuite/ReleaseNotes/17.01.00
https://launchpad.net/ubuntu/+source/fwts

Attacking UEFI Runtime Services

~ hucktech ~ Leave a comment

Ulf has an informative new article (and video) about attacking UEFI Runtime Services on Linux-based systems using PCILeech:

Attackers with physical access are able to attack the firmware on many fully patched computers with DMA – Direct Memory Access. Once code execution is gained in UEFI/EFI Runtime Services it is possible to use this foothold to take control of a running Linux system. The Linux 4.8 kernel fully randomizes the physical memory location of the kernel. There is a high likelyhood that the kernel will be randomized above 4GB on computers with sufficient memory. This means that DMA attack hardware only capable of 32-bit addressing (4GB), such as PCILeech, cannot reach the Linux kernel directly. Since the EFI Runtime Services are usually located below 4GB they offer a way into Linux on high memory EFI booting systems. Please see the video below for an example of how an attack may look like. […]

Full post:

http://blog.frizk.net/2017/01/attacking-uefi-and-linux.html

 

James on Linux and TPM (and TouSerS)

~ hucktech ~ Leave a comment

James Bottomley has a new blog post on TPM v2 and Linux:

TPM2 and Linux

See his pervious blog posts for more on TPM and Linux.

Blogging aside, James also posted a TPM2 patch to TouSerS to allow support for OpenSSL:

[TrouSerS-tech] [PATCH 0/1] TPM2 engine support for openssl

This is a completed version of the original RFC.  It’s working now both on the TPM2 simulator and on real hardware (I’ve converted my laptop to TPM2).  I’ve updated it to use the latest version of the ASN.1 for the key format (still using a TCG OID). I have it building here (it’s what I’m currently using for my laptop VPNs):

https://build.opensuse.org/package/show/home:jejb1:Tumbleweed/openssl_tpm_engine

But note that this version also has experimental patches to activate the in-kernel TPM Resource Manager because for multiple applications TPM2 really doesn’t work well without one.  Since the patch for the RM is currently not upstream (yet), it’s not going to work unless you have a patched kernel.

More info:
https://lists.sourceforge.net/lists/listinfo/trousers-tech

MapleSyrup: ARM security tool

~ hucktech ~ Leave a comment

https://twitter.com/suqdiq/status/805453613699043328

Maplesyrup Register Display Tool:
Maplesyrup is a tool that can be used to help determine the security state of an ARM-based device by examining the system register interface of the CPU. Maplesyrup is for anyone who has low level access to a handset or single-board PC running an ARMv7A/v8A based processor and is interested in knowing the register level configuration of their CPU at OS runtime. These registers contain featureset and security information that may influence operation of the system kernel and running applications. Linux provides featureset and platform information to the user in the /proc and /sys filesystems, but the configurations governing how these features operate is sometimes hidden to the user. In some cases, the OS will make use of the information to conform to implementation specific features and not indicate this to the user. In other cases, these features may not be managed by the operating system at all, but nevertheless could potentially affect the operation of the system by configuring how a CPU controls access to security domains, executes specific instructions, and handles CPU exceptions.[…]

 

https://github.com/iadgov/Maplesyrup

 

James on Linux TPM stack

~ hucktech ~ Leave a comment

James has a new blog post that gives a good introduction to the Linux TPM stack:

“[…]One of the great advantages of the TPM, instead of messing about with USB pkcs11 tokens, is that it has a file format for TPM keys (I’ll explain this later) which can be used directly in place of standard private key files.  However, before we get there, lets discuss some of the basics of how your TPM works and how to make use of it.[…]”

Using Your TPM as a Secure Key Store

 

Linux Kernel lockdown

~ hucktech ~ Leave a comment

David Howells of Red Hat submitted a 16-part patch to the Linux-(Security,EFI,Kernel) mailing lists, with an interesting security patch for the Linux kenel. The patch includes contributions from: David Howells, Josh Boyer, Kyle McMartin, Matthew Garrett, and Dave Young. Quoting the patch announcement:

These patches provide a facility by which a variety of avenues by which userspace can feasibly modify the running kernel image can be locked down. These include:

* No unsigned modules and no modules for which can’t validate the signature.
* No use of ioperm(), iopl() and no writing to /dev/port.
* No writing to /dev/mem or /dev/kmem.
* No hibernation.
* Restrict PCI BAR access.
* Restrict MSR access.
* No kexec_load().
* Certain ACPI restrictions.
* Restrict debugfs interface to ASUS WMI.

The lock-down can be configured to be triggered by the EFI secure boot status, provided the shim isn’t insecure.  The lock-down can be lifted by typing SysRq+x on a keyboard attached to the system. They are dependent for some EFI definitions on the keys-uefi branch.

Copy secure_boot flag in boot params across kexec reboot
Add the ability to lock down access to the running kernel image
efi: Get the secure boot status
efi: Lock down the kernel if booted in secure boot mode
efi: Disable secure boot if shim is in insecure mode
efi: Add EFI_SECURE_BOOT bit
hibernate: Disable when the kernel is locked down
acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down
Add a sysrq option to exit secure boot mode
kexec: Disable at runtime if the kernel is locked down
PCI: Lock down BAR access when the kernel is locked down
x86: Lock down IO port access when the kernel is locked down
ACPI: Limit access to custom_method when the kernel is locked down
asus-wmi: Restrict debugfs interface when the kernel is locked down
Restrict /dev/mem and /dev/kmem when the kernel is locked down
x86: Restrict MSR access when the kernel is locked down

More information:
http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=keys-lockdown
http://vger.kernel.org/majordomo-info.html

Linux 4.10 UEFI changes

~ hucktech ~ Leave a comment

Matt Fleming posted UEFI changes for Linux 4.10 kernel.

Folks, please pull the following v4.10 material. There isn’t a huge amount of stuff here. The biggest change is the EFI dev path parser code from Lukas to get thunderbolt working on his macbook.
 * Fix an allocation bug in the generic EFI libstub where alignment and adjusted size isn’t taken into account – Roy Franz
 * Update the EFI MAINTAINERS entry to include ARM and arm64 files and directories – Ard Biesheuvel
 * Add new feature to seed the RNG from the stashed value returned by EFI_RNG_PROTOCOL in EFI stub and wire up for ARM/arm64 – Ard Biesheuvel
 * Retrieve Apple device properties from within the EFI stub to fully support thunderbolt devices on Apple Macbooks – Lukas Wunner

More details on the Thunderbolt patch:

thunderbolt: Use Device ROM retrieved from EFI:
Macs with Thunderbolt 1 do not have a unit-specific DROM: The DROM is empty with uid 0x1000000000000. (Apple started factory-burning a unit- specific DROM with Thunderbolt 2.) Instead, the NHI EFI driver supplies a DROM in a device property. Use it if available. It’s only available when booting with the efistub.  If it’s not available, silently fall back to our hardcoded DROM.  The size of the DROM is always 256 bytes. The number is hardcoded into the NHI EFI driver. This commit can deal with an arbitrary size however, just in case they ever change that.  Background information: The EFI firmware volume contains ROM files for the NHI, GMUX and several other chips as well as key material. This strategy allows Apple to deploy ROM or key updates by simply publishing an EFI firmware update on their website. Drivers do not access those files directly but rather through a file server via EFI protocol AC5E4829-A8FD-440B-AF33-9FFE013B12D8. Files are identified by GUID, the NHI DROM has 339370BD-CFC6-4454-8EF7-704653120818.  The NHI EFI driver amends that file with a unit-specific uid. The uid has 64 bit but its entropy is much lower: 24 bit represent the model, 24 bit are taken from a serial number, 16 bit are fixed. The NHI EFI driver obtains the serial number via the DataHub protocol, copies it into the DROM, calculates the CRC and submits the result as a device property.  A modification is needed in the resume code where we currently read the uid of all switches in the hierarchy to detect plug events that occurred during sleep. On Thunderbolt 1 root switches this will now lead to a mismatch between the uid of the empty DROM and the EFI DROM. Exempt the root switch from this check: It’s built in, so the uid should never change. However we continue to *read* the uid of the root switch, this seems like a good way to test its reachability after resume.

http://vger.kernel.org/majordomo-info.html
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git tags/efi-next