Meltdown & Spectre - Kernel Side-Channel Attacks - CVE-2017-5754 CVE-2017-5753 CVE-2017-5715

Public Date:
Updated -
Status
Resolved
Impact
Important

Red Hat has been made aware of multiple microarchitectural (hardware) implementation issues affecting many modern microprocessors, requiring updates to the Linux kernel, virtualization-related components, and/or in combination with a microcode update.  An unprivileged attacker can use these flaws to bypass conventional memory security restrictions in order to gain read access to privileged memory that would otherwise be inaccessible. There are 3 known CVEs related to this issue in combination with Intel, AMD, and ARM architectures. Additional exploits for other architectures are also known to exist. These include IBM System Z,  POWER8 (Big Endian and Little Endian), and POWER9 (Little Endian).

Background Information

An industry-wide issue was found with the manner in which many modern microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimization). There are three primary variants of the issue which differ in the way the speculative execution can be exploited. All three rely upon the fact that modern high performance microprocessors implement both speculative execution, and utilize VIPT (Virtually Indexed, Physically Tagged) level 1 data caches that may become allocated with data in the kernel virtual address space during such speculation.

The first two variants abuse speculative execution to perform bounds-check bypass (CVE-2017-5753), or by utilizing branch target injection (CVE-2017-5715) to cause kernel code at an address under attacker control to execute speculatively. Collectively these are known as "Spectre".  Both variants rely upon the presence of a precisely-defined instruction sequence in the privileged code, as well as the fact that memory accesses may cause allocation into the microprocessor’s level 1 data cache even for speculatively executed instructions that never actually commit (retire).  As a result, an unprivileged attacker could use these two flaws to read privileged memory by conducting targeted cache side-channel attacks. These variants could be used not only to cross syscall boundary (variant 1 and variant 2) but also guest/host boundary (variant 2).

The third variant (CVE-2017-5754) relies on the fact that, on impacted microprocessors, during speculative execution of instruction permission faults, exception generation triggered by a faulting access is suppressed until the retirement of the whole instruction block. Researchers have called this exploit "Meltdown".  Subsequent memory accesses may cause an allocation into the L1 data cache even when they reference otherwise inaccessible memory locations. As a result, an unprivileged local attacker could read privileged (kernel space) memory (including arbitrary physical memory locations on a host) by conducting targeted cache side-channel attacks.

Acknowledgements

Red Hat would like to thank Google Project Zero for reporting these flaws.

Additional References

Is CPU microcode available to address CVE-2017-5715 via the microcode_ctl package ?

Have questions? Watch the webinar on demand.

Find out more about the Speculative Store Bypass, which was announced in May 2018.

What are Meltdown and Spectre? Here’s what you need to know.

https://googleprojectzero.blogspot.ca/2018/01/reading-privileged-memory-with-side.html 

https://meltdownattack.com/

Speculative Execution Exploit Performance Impacts - Describing the performance impacts to security patches for CVE-2017-5754 CVE-2017-5753 and CVE-2017-5715Controlling the Performance Impact of Microcode and Security Patches for CVE-2017-5754 CVE-2017-5715 and CVE-2017-5753 using Red Hat Enterprise Linux Tunables

AMD Reccomendations for CVE-2017-5715

Additional Red Hat Product References

Options to address CVE-2017-5753 on XEN platform

Impacts of CVE-2017-5754, CVE-2017-5753, and CVE-2017-5715 to Red Hat Virtualization products

Impact of CVE-2017-5754, CVE-2017-5753, and CVE-2017-5715 to Red Hat OpenStack

Satellite 6 How to Provide Errata for Meltdown/Spectre to Content Hosts (CVE-2017-5753, CVE-2017-5754, and CVE-2017-5715)

Impacted Products

Red Hat Product Security has rated this update as having a security impact of Important.

The following Red Hat product versions are impacted:

  • Red Hat Enterprise Linux 5

  • Red Hat Enterprise Linux 6

  • Red Hat Enterprise Linux 7

  • Red Hat Atomic Host

  • Red Hat Enterprise MRG 2

  • Red Hat OpenShift Online v2

  • Red Hat OpenShift Online v3

  • Red Hat Virtualization (RHEV-H/RHV-H)

  • Red Hat Enterprise Linux OpenStack Platform 6.0 (Juno)

  • Red Hat Enterprise Linux OpenStack Platform 7.0 (Kilo) for RHEL7

  • Red Hat Enterprise Linux OpenStack Platform 7.0 (Kilo) director for RHEL7

  • Red Hat OpenStack Platform 8.0 (Liberty)

  • Red Hat OpenStack Platform 8.0 (Liberty) director

  • Red Hat OpenStack Platform 9.0 (Mitaka)

  • Red Hat OpenStack Platform 9.0 (Mitaka) director

  • Red Hat OpenStack Platform 10.0 (Newton)

  • Red Hat OpenStack Platform 11.0 (Ocata)

  • Red Hat OpenStack Platform 12.0 (Pike)

While Red Hat's Linux Containers are not directly impacted by kernel issues, their security relies upon the integrity of the host kernel environment. Red Hat recommends that you use the most recent versions of your container images. The Container Health Index, part of the Red Hat Container Catalog, can always be used to verify the security status of Red Hat containers. To protect the privacy of the containers in use, you will need to ensure that the Container host (such as Red Hat Enterprise Linux or Atomic Host) has been updated against these attacks. Red Hat has released an updated Atomic Host for this use case.

Attack Description and Impact

The attacks described in this article abuse the speculative execution capability of modern high-performance microprocessors. Modern microprocessors implement a design optimization known as “Out-of-Order” (OoO) execution, meaning the microprocessor will begin to execute independent instructions as soon as their data dependencies become available (so-called “data flow” model) rather than always executing instructions in the literal order provided by the programmer through their application binary. The illusion of a sequential execution is maintained within the processor by means of various internal reordering structures that buffer these intermediate execution states of the processor and present the in-order results. Out-of-Order (OoO) Execution was originally invented by Robert Tomasulo in 1967 for use in the early IBM mainframe systems. In the intervening decades, it has become a standard feature of nearly all microprocessors. 

An extension of the Out-of-Order execution model adds highly sophisticated branch prediction algorithms that aim to predict whether a given path (branch) of software code will be executed. A branch can be thought of as changing the flow of instructions being executed by the processor in response to an “if” statement of the form “if this, then do A, otherwise do B”. The condition upon which a branch is taken or not taken often depends upon data that may not immediately be available (for example, because it requires a load from slower RAM into the internal microprocessor cache hierarchy). Since the branch condition may not be ready in a timely manner, the processor may begin to speculatively execute the most likely path, based on input from the branch predictor. Results from this execution are stored in such a manner that the entire path can be discarded if the speculated branch direction later turns out to be incorrect. Thus, speculative execution is normally completely invisible to the programmer, or to other users of the same system.

The attacks described in this article rely upon breaking open the black box that is the internal state of the microprocessor during speculative execution. In particular, the attacks rely upon a technique known as cache side-channel analysis. During speculative execution, a processor will not intermediately make results available in memory or registers visible to the programmer, to other processors, or to other running applications. Yet, in order to access memory within speculated code paths, it must bring the data in the processor cache. Side-channel analysis allows an attacker to observe speculated allocations (loads) into the system caches, even those coming from execution paths that ultimately have been discarded. A specially crafted program can then be designed to speculatively perform loads into the cache from privileged memory locations, and monitor the results which can be used to infer the content of that privileged memory.

One case that triggers CPU speculative execution is branches. An attacker can start by training the branch predictor that a particular branch in kernel code is heavily taken (or not taken). The next time the branch executes, the processor will start executing the code in the direction chosen by the attacker. If the attacker chooses a path that loads a value from memory, such load will be executed speculatively.  Attacks against branch prediction can (in some affected microprocessor implementations) be extended across the kernel/hypervisor boundary, allowing unprivileged guest Operating Systems to exert influence over the execution of the hypervisor and, when combined with side-channel analysis, to extract sensitive hypervisor memory.

The effects of speculative execution however can be even more wide-ranging. Because the internal state of the microprocessor is not visible to the programmer, or to other users or applications running on the system, the processor may perform speculative data accesses even before checking whether they are permitted. Permission checks will occur in parallel and ultimately trigger an abort of the speculation prior to retiring the speculated instructions and making their execution results visible outside the processor. If the processor speculatively uses cached data from memory prior to completing the permission checks, then it becomes possible to observe that data by using it in subsequent memory accesses.

One example of such permission checks is page access checks from the memory management unit (MMU). Paging, also known as virtual memory, is a common feature of high performance microprocessors; it lets the operating system control the mapping of virtual addresses into the physical addresses of the system RAM, and also limit accesses to the virtual addresses through access control bits. For example, a page can be marked as “read-only” (so that writes cause a page fault exception) or as “kernel memory” (so that user-mode accesses cause a page fault exception).

Because the processor’s permission checks enforce that user applications cannot access kernel memory, it is standard practice in the industry for operating system kernels (including Linux) to map kernel virtual memory addresses into the same address space as user applications. Doing so creates a significant performance advantage since applications make frequent use of kernel-provided system calls, and switching address spaces during each system call would incur a significant performance overhead. Each switch would require flushing (invalidating) the content of many internal CPU structures, such as TLBs (Translation Lookaside Buffers) that cache virtual-to-physical memory translations and accelerate the use of virtual memory.

Sharing the page tables between the kernel and user applications, however, enables another kind of attack against speculative execution. In this case, the preparatory phase has the attacker trick the kernel into loading an “interesting” virtual address into the processor’s Level 1 (L1) data cache. The L1 data cache is commonly organized using a technique known as VIPT (Virtually Indexed, Physically Tagged), which lets the virtual-to-physical address translation and permission checks occur in parallel with access. In the presence of a shared virtual address space, kernel privileged virtual addresses might be accessed speculatively through the L1 cache by untrusted user code during speculative execution, and the loaded values can be used further down the speculatively-executed path. A second speculative memory access can thus fill the cache in a manner that depends on privileged memory contents, and the effects can be observed to derive those contents.

These microprocessor side-channel attacks may allow an untrusted user with access to a machine to extract sensitive information from privileged kernel or hypervisor memory, as well as from other applications or virtual machines running on the same system. Mitigation involves a number of discrete steps, some or all of which may be required depending upon the exact make and model of the microprocessor, each of which may be vulnerable to a differing extent to each variant of the attack:

  • Separating the kernel and user virtual address spaces: this is performed using a design change to the Operating System kernel known as KPTI (Kernel Page Table Isolation), sometimes referred to using the older name “KAISER”. 
  • Disabling indirect branch prediction upon entry into the kernel or into the hypervisor: New capabilities have been added to many microprocessors across the industry through microcode, millicode, firmware, and other updates. These new capabilities are leveraged by updates to Red Hat Enterprise Linux which control their use.
  • Fencing speculative loads of certain memory locations: Such loads have to be annotated through small changes to the Linux kernel, which have been integrated into Red Hat updates.

These software solutions, in combination with microcode, millicode, and firmware updates can mitigate the attacks described in this article. However, the mitigation comes at some cost to system performance. Depending upon the specific system, make, and model of the microprocessors, as well as the characteristics of the workloads, the performance impact can be significant. Red Hat is taking a proactive position that favors security over performance, while allowing users the flexibility to assess their own environment and make appropriate tradeoffs through selectively enabling and disabling the various mitigations.

The Red Hat Performance Engineering team has created a Knowledgebase article reporting observed performance impact for a variety of representative workloads, and describing options users can take to disable parts of the security fixes to regain the desired level of performance if the customer is confident their computers are physically isolated.  Additional performance data will be published as this incident develops.

The Red Hat Performance Engineering and Product Engineering teams have developed a Knowledgebase article detailing the tunables available to selectively enable or disable these new security features.

Additional guidance for subscribers using AMD-based systems can be found in this Knowledgebase article.

Detection & Diagnosis

Determine if your system is vulnerable

Red Hat has created a Labs app to assist in detection of exposure to these vulnerabilities.  Subscribers can use the following link to access our Labs tool.

Determine if your system is vulnerable. Use the detection script to determine if your system is currently vulnerable to this flaw. To verify the legitimacy of the script, you can download the detached GPG signature as well. The current version of the script is 3.0.

For subscribers running Red Hat Virtualization products, a Knowledgebase article has been created to verify OEM-supplied microcode/firmware has been applied.

Take Action

Red Hat customers running affected versions of the Red Hat products are strongly recommended to update them as soon as errata are available. Customers are urged to apply the appropriate updates immediately.  All impacted products should apply fixes to mitigate all 3 variants; CVE-2017-5753 (variant 1),  CVE-2017-5715 (variant 2), and CVE-2017-5754 (variant 3).

NOTES

  • Meltdown is the branded name for CVE-2017-5754 (variant 3)
  • Spectre is the branded name for the combined CVE-2017-5753 (variant 1) & CVE-2017-5715 (variant 2)
  • Due to the nature of changes required, a kpatch for customers running Red Hat Enterprise Linux 7.2 or greater will NOT be available.
  • Variant 2 can be exploited both locally (within the same OS) and through the virtualization guest boundary. Fixes require CPU microcode/firmware to activate.  Subscribers are advised to contact their hardware OEM to receive the appropriate microcode/firmware for their processor.  An additional Knowledgebase article is available with more details.
  • Carefully read the text of the Security Errata. Not all architectures had mitigations released initially. The x86_64 mitigations do not include Red Hat Enterprise Linux 6 32bit kernels.
  • For customers using Red Hat OpenStack Platform, an additional Knowledgebase article is also available.
  • For customers using Red Hat Satellite 6, an additional Satellite 6 Knowledgebase article is also available. NOTE: Please use the table below to help quickly identify the specific RHSA ID's that you want to apply to your systems.

CVE-2017-5754 (variant 3, aka Meltdown) patches for 32-bit Red Hat Enterprise Linux 5

Red Hat has no current plans to provide mitigations for the Meltdown vulnerability in 32-bit Red Hat Enterprise Linux 5 environments.

Following many hours of engineering investigation and analysis, Red Hat has determined that introducing changes to the Red Hat Enterprise Linux 5 environment would destabilize customer deployments and violate our  application binary interface (ABI) and kernel ABI commitments to customers who rely on Red Hat Enterprise Linux 5 to be absolutely stable.

Although Red Hat has delivered patches to mitigate the Meltdown vulnerability in other supported product offerings, the 32-bit Red Hat Enterprise Linux 5 environment presents unique challenges.  The combination of limited address space in 32-bit environments plus the mechanism for passing control from the userspace to kernel and limitations on the stack during this transfer make the projected changes too invasive and disruptive for deployments that require the highest level of system stability.  By contrast, 32-bit Meltdown mitigations have been delivered for Red Hat Enterprise Linux 6, where the changes are far less invasive and risky.

Updates for Affected Products

ProductPackageAdvisory/UpdateApplicable to Variant
Red Hat Enterprise Linux 7 (z-stream)kernelRHSA-2018:00071,2,3
Red Hat Enterprise Linux 7kernel-rtRHSA-2018:00161,2,3
Red Hat Enterprise Linux 7libvirtRHSA-2018:00292
Red Hat Enterprise Linux 7qemu-kvmRHSA-2018:00232
Red Hat Enterprise Linux 7dracutRHBA-2018:00422
Red Hat Enterprise Linux 7.3 Extended Update Support**kernelRHSA-2018:00091,2,3
Red Hat Enterprise Linux 7.3 Extended Update Support**libvirtRHSA-2018:00312
Red Hat Enterprise Linux 7.3 Extended Update Support**qemu-kvmRHSA-2018:00272
Red Hat Enterprise Linux 7.3 Extended Update Support**dracutRHBA-2018:00432
Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions, & Advanced Update Support***,****kernelRHSA-2018:00101,2,3
Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions, & Advanced Update Support***,****libvirtRHSA-2018:00322
Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions, & Advanced Update Support***,****qemu-kvmRHSA-2018:00262
Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions, & Advanced Update Support***,****dracutRHBA-2018:00622
Red Hat Enterprise Linux 6 (z-stream)kernelRHSA-2018:00081,2,3
Red Hat Enterprise Linux 6libvirtRHSA-2018:00302
Red Hat Enterprise Linux 6qemu-kvmRHSA-2018:00242
Red Hat Enterprise Linux 6.7 Extended Update Support**kernelRHSA-2018:00111,2,3
Red Hat Enterprise Linux 6.7 Extended Update Support**libvirtRHSA-2018:01082
Red Hat Enterprise Linux 6.7 Extended Update Support**qemu-kvmRHSA-2018:01032
Red Hat Enterprise Linux 6.6 Advanced Update Support***,****kernelRHSA-2018:00171,2,3
Red Hat Enterprise Linux 6.6 Advanced Update Support***,****libvirtRHSA-2018:01092
Red Hat Enterprise Linux 6.6 Advanced Update Support***,****qemu-kvmRHSA-2018:01042
Red Hat Enterprise Linux 6.5 Advanced Update Support***kernelRHSA-2018:00221,2,3
Red Hat Enterprise Linux 6.5 Advanced Update Support***libvirtRHSA-2018:01102
Red Hat Enterprise Linux 6.5 Advanced Update Support***qemu-kvmRHSA-2018:01052
Red Hat Enterprise Linux 6.4 Advanced Update Support***kernelRHSA-2018:00181,2,3
Red Hat Enterprise Linux 6.4 Advanced Update Support***libvirtRHSA-2018:01112
Red Hat Enterprise Linux 6.4 Advanced Update Support***qemu-kvmRHSA-2018:01062
Red Hat Enterprise Linux 6.2 Advanced Update Support***kernelRHSA-2018:00201,2,3
Red Hat Enterprise Linux 6.2 Advanced Update Support***libvirtRHSA-2018:01122
Red Hat Enterprise Linux 6.2 Advanced Update Support***qemu-kvmRHSA-2018:01072
Red Hat Enterprise Linux 5 Extended Lifecycle Support*kernelRHSA-2018:0292

1,2,3

Red Hat Enterprise Linux 5.9 Advanced Update Support***kernelRHSA-2018:04641,3
RHEL Atomic HostkernelImages respun on 5 January 20181,2,3
Red Hat Enterprise MRG 2kernel-rtRHSA-2018:00211,2,3
Red Hat Virtualization 4 (RHEV-H/RHV-H)redhat-virtualization-hostRHSA-2018:00471,2,3
Red Hat Virtualization 4 (RHEV-H/RHV-H)rhvm-applianceRHSA-2018:00451,2,3
Red Hat Virtualization 4 (RHEV-H/RHV-H)qemu-kvm-rhevRHSA-2018:00252
Red Hat Virtualization 4 (RHEV-H/RHV-H)vdsmRHSA-2018:00502
Red Hat Virtualization 4 (RHEV-H/RHV-H)ovirt-guest-agent-dockerRHSA-2018:00472
Red Hat Virtualization 4 (RHEV-H/RHV-H)rhevm-setup-pluginsRHSA-2018:00512
Red Hat Virtualization 3 (RHEV-H/RHV-H)redhat-virtualization-hostRHSA-2018:00441,2,3
Red Hat Virtualization 3 ELS (RHEV-H/RHV-H)rhev-hypervisor7RHSA-2018:00461,2,3
Red Hat Virtualization 3 ELS (RHEV-H/RHV-H)qemu-kvm-rhevRHSA-2018:00282
Red Hat Virtualization 3 ELS (RHEV-H/RHV-H)vdsmRHSA-2018:00482
Red Hat Virtualization 3 ELS (RHEV-H/RHV-H)rhevm-setup-pluginsRHSA-2018:00522
Red Hat Enterprise Linux OpenStack Platform 6.0 (Juno) for RHEL7qemu-kvm-rhevRHSA-2018:00542
Red Hat Enterprise Linux OpenStack Platform 7.0 (Kilo) for RHEL7qemu-kvm-rhevRHSA-2018:00552
Red Hat Enterprise Linux OpenStack Platform 7.0 (Kilo) director for RHEL7director imagesRHBA-2018:00641,2,3
Red Hat OpenStack Platform 8.0 (Liberty)qemu-kvm-rhevRHSA-2018:00562
Red Hat OpenStack Platform 8.0 (Liberty)director imagesRHBA-2018:00651,2,3
Red Hat OpenStack Platform 9.0 (Mitaka)qemu-kvm-rhevRHSA-2018:00572
Red Hat OpenStack Platform 9.0 (Mitaka)director imagesRHBA-2018:00691,2,3
Red Hat OpenStack Platform 10.0 (Newton)qemu-kvm-rhevRHSA-2018:00582
Red Hat OpenStack Platform 10.0 (Newton)director imagesRHBA-2018:00671,2,3
Red Hat OpenStack Platform 11.0 (Ocata)qemu-kvm-rhevRHSA-2018:00592
Red Hat OpenStack Platform 11.0 (Ocata)director imagesRHBA-2018:00681,2,3
Red Hat OpenStack Platform 12.0 (Pike)qemu-kvm-rhevRHSA-2018:00602
Red Hat OpenStack Platform 12.0 (Pike)director imagesRHBA-2018:00661,2,3
Red Hat OpenStack Platform 12.0 (Pike)containersRHBA-2018:00701,2,3


*An active ELS subscription is required for access to this patch.  Please contact Red Hat sales or your specific sales representative for more information if your account does not have an active ELS subscription.

**An active EUS subscription is required for access to this patch.  Please contact Red Hat sales or your specific sales representative for more information if your account does not have an active EUS subscription.

What is the Red Hat Enterprise Linux Extended Update Support Subscription?

***An active AUS subscription is required for access to this patch in RHEL AUS.

What is Advanced mission critical Update Support (AUS)?

****An active TUS subscription is required for access to this patch in RHEL TUS.

***** Subscribers should contact their hardware OEMs to get the most up-to-date versions of CPU microcode/firmware.

Mitigation

There is no known mitigation, other than applying vendor software updates combined with hardware OEMs CPU microcode/fiirmware. All Red Hat customers should apply vendor solutions to patch their CPUs, and update the kernel as soon as patches are available.

Customers are advised to take a risk-based approach in mitigating this issue.  Systems that require high degrees of security and trust should be addressed first, and should be isolated from untrusted systems until such time as treatments can be applied to those systems to reduce the risk of exploit.

Customers running Xen hypervisors should be aware of technical limitations of that software that cannot completely eliminate the variant 2 exploit, and cannot eliminate the variant 3 exploit on paravirtualized guests.  Red Hat has prepared a Knowledgebase article detailing the Xen situation and options available to Xen hypervisor users.

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23 Comments

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I tried the latest detection script from today (version 2.3) on a system with the updated kernel for RHEL5 ELS, but it says that spectre #2 (CVE-2017-5715) mitigation is not available for RHEL5 yet. I don't see any mention of this in the RHEL5 advisory (RHSA-2018:0292), and it contradicts the bugzilla bug status, which says in the last comment that RHEL5 ELS is now "addressed":

https://bugzilla.redhat.com/show_bug.cgi?id=1519780

This is the script output:

# ./spectre-meltdown--a79614b.sh

This script is primarily designed to detect Spectre / Meltdown on supported
Red Hat Enterprise Linux systems and kernel packages.
Result may be inaccurate for other RPM based systems.

Detected CPU vendor: Intel
Running kernel: 2.6.18-426.el5

Variant #1 (Spectre): Mitigated
CVE-2017-5753 - speculative execution bounds-check bypass
   - Kernel with mitigation patches: OK

Variant #2 (Spectre): Vulnerable
CVE-2017-5715 - speculative execution branch target injection
   - Kernel with mitigation patches: NO
   - HW support / updated microcode: Cannot detect without updated kernel
   - IBRS: Not disabled on kernel commandline
   - IBPB: Not disabled on kernel commandline

Variant #3 (Meltdown): Mitigated
CVE-2017-5754 - speculative execution permission faults handling
   - Kernel with mitigation patches: OK
   - PTI: Not disabled on kernel commandline

Mitigation for Variant #2 is not available for RHEL5 yet.

Kernel mitigations for variant 2 (CVE-2017-5715) are currently only available for s390 and not x86-64. RHSA-2018:0292 mentions that in the advisory description.

It says:

In this update mitigations for IBM zSeries (S390) and x86-64 architectures are provided.

If you are referring to the "(CVE-2017-5715, Important, S390)" at the end of the line item, this is using terse in-house phrasing, and is not clear what it means, given the above statement and the bugzilla report, which says "Hardware: All Linux", and does not mention any hardware exceptions:

https://bugzilla.redhat.com/show_bug.cgi?id=1519780

This issue has been addressed in the following products:
  Red Hat Enterprise Linux 5 Extended Lifecycle Support

I would suggest to be more clear in the advisory (and the bugzilla report) and highlight the exceptions in the main sentence above, and not simply mention it in a terse aside without explanation.

It seems that these mitigation's are only for 64-bit products. Are RHEL 6 and RHEL 5 ELS 32-bit kernel mitigation's being developed? Thanks.

There are both 64-bit and 32-bit package listings for both on the same page:

RHEL6

RHEL5 ELS

At the top of this page it says: The x86_64 mitigations do not include Red Hat Enterprise Linux 6 32bit kernels.

And on each of the related advisory pages you linked to it says this on them: RHEL 6 says this: In this update mitigations for x86-64 architecture are provided. RHEL 5 says this: In this update mitigations for IBM zSeries (S390) and x86-64 architectures are provided.

It seems these updates have nothing to do with mitigating the issues on 32-bit although the packages were updated. After, running the detection script it still says the systems are vulnerable after updating the kernels.

The advisories are not written very clearly, and have contradictions. I believe the line at the top means the package set for the x86_64 distribution does not contain fixes for 32-bit kernels (as opposed to the package set for the i386 distribution, which does).

If you click on the "Updated Packages" tab in each advisory, there is the "x86_64" (64-bit) package set, and if you scroll down more, the "i386" (32-bit) package set. Note that for RHEL6, there are also advisories for "libvirt" and "qemu-kvm" (if you have these installed).

Unfortunately, I do not think this is the case. I have installed the 32-bit kernel (kernel-2.6.32-696.18.7.el6.i686) on a RHEL6 32-bit server, rebooted, run the spectre_meltdown script and it still says it is vulnerable for all 3 variants.

Why is RHEL-7.1 not listed here? Are there going to be no updates for it?

May I know what has been updated on this page last Friday (09-Mar)? This helps check if it is applicable to us so that we can take appropriate actions.

Many tks

Intel released a new microcode package, will this be incorporated into microcode_ctl soon? (https://downloadcenter.intel.com/download/27591/Linux-Processor-Microcode-Data-File?v=t)

Hello Klaas. At this time our Line of Business is still deciding when they will release microcode back through RHEL. For the time being, your hardware provider is still the BEST place to go to get that code (since each hardware provider makes adjustments to the microcode the original CPU manufacturer provided them). One nice consolidated place to get all of the up-to-date microcode/millicode/firmware for chips is the Linux Vendor Firmware Service: https://fwupd.org/

Hi support.

The detection script "spectre-meltdown--a79614b.sh" (Version: 2.3) does not accurately identify vulnerabilities for pre-Skylake CPUs. For example, from your article (https://access.redhat.com/articles/3311301#architectural-defaults-11):

"pti=1 ibrs=0 retp=1 ibpb=1-> fix variant#1 #2 #3 for pre-Skylake cpus"

It's true on my old server with a fresh BIOS:

Kernel is Linux 3.10.0-693.21.1.el7.x86_64 #1 SMP Wed Mar 7 19:03:37 UTC 2018 x86_64
CPU is Intel(R) Pentium(R) CPU G850 @ 2.90GHz
# cat /sys/kernel/debug/x86/pti_enabled
1
# cat /sys/kernel/debug/x86/ibrs_enabled
0
# cat /sys/kernel/debug/x86/retp_enabled
1
# cat /sys/kernel/debug/x86/ibpb_enabled
1

I.e., again from your article above:

"For Intel processors prior to Skylake, Retpolines are used instead of the ibrs feature for mitigation against Spectre variant 2."

I.e., my old server with fresh BIOS and kernel is completely protected from the above-mentioned vulnerabilities. But your detection script claims the opposite, for example:

# ./spectre-meltdown--a79614b.sh

This script is primarily designed to detect Spectre / Meltdown on supported
Red Hat Enterprise Linux systems and kernel packages.
Result may be inaccurate for other RPM based systems.

Detected CPU vendor: Intel
Running kernel: 3.10.0-693.21.1.el7.x86_64

Variant #1 (Spectre): Mitigated
CVE-2017-5753 - speculative execution bounds-check bypass
   - Kernel with mitigation patches: OK

Variant #2 (Spectre): Vulnerable
CVE-2017-5715 - speculative execution branch target injection
   - Kernel with mitigation patches: OK
   - HW support / updated microcode: YES
   - IBRS: Not disabled on kernel commandline
   - IBPB: Not disabled on kernel commandline

Variant #3 (Meltdown): Vulnerable
CVE-2017-5754 - speculative execution permission faults handling
   - Kernel with mitigation patches: OK
   - PTI: Not disabled on kernel commandline

Red Hat recommends that you:

Note about virtualization
In virtualized environment, there are more steps to mitigate the issue, including:
* Host needs to have updated kernel and CPU microcode
* Host needs to have updated virtualization software
* Guest needs to have updated kernel
* Hypervisor needs to propagate new CPU features correctly
For more details about mitigations in virtualized environment see:
https://access.redhat.com/articles/3331571

For more information about the vulnerabilities see:
https://access.redhat.com/security/vulnerabilities/speculativeexecution

It's like a script bug. What do you say about this?

It look like script out put is confusing .. I am not sure how to read the output is there any guideline to read the out put.

cat /sys/kernel/debug/x86/pti_enabled 1 cat /sys/kernel/debug/x86/ibrs_enabled 0 cat /sys/kernel/debug/x86/retp_enabled 1 cat /sys/kernel/debug/x86/ibpb_enabled 1

This script is primarily designed to detect Spectre / Meltdown on supported Red Hat Enterprise Linux systems and kernel packages. Result may be inaccurate for other RPM based systems.

Detected CPU vendor: Intel Running kernel: 3.10.0-693.21.1.el7.x86_64

Variant #1 (Spectre): Mitigation: Load fences CVE-2017-5753 - speculative execution bounds-check bypass - Kernel with mitigation patches: OK

Variant #2 (Spectre): Mitigation: Full retpoline CVE-2017-5715 - speculative execution branch target injection - Kernel with mitigation patches: OK - HW support / updated microcode: YES - IBRS: Not disabled on kernel commandline - IBPB: Not disabled on kernel commandline - Retpolines: Not disabled on kernel commandline

Variant #3 (Meltdown): Mitigation: PTI CVE-2017-5754 - speculative execution permission faults handling - Kernel with mitigation patches: OK - PTI: Not disabled on kernel commandline

Note about virtualization In virtualized environment, there are more steps to mitigate the issue, including: * Host needs to have updated kernel and CPU microcode * Host needs to have updated virtualization software * Guest needs to have updated kernel * Hypervisor needs to propagate new CPU features correctly For more details about mitigations in virtualized environment see: https://access.redhat.com/articles/3331571

For more information about the vulnerabilities see: https://access.redhat.com/security/vulnerabilities/speculativeexecution

Hi all!

It seems that yesterday the above bug of the detection script was fixed :-).

For example, here is the output of the new detection script "spectre-meltdown-180327_0.sh" (Version: 2.4) on the same system as above:

# ./spectre-meltdown-180327_0.sh

This script is primarily designed to detect Spectre / Meltdown on supported
Red Hat Enterprise Linux systems and kernel packages.
Result may be inaccurate for other RPM based systems.

Detected CPU vendor: Intel
Running kernel: 3.10.0-693.21.1.el7.x86_64

Variant #1 (Spectre): Mitigation: Load fences
CVE-2017-5753 - speculative execution bounds-check bypass
   - Kernel with mitigation patches: OK

Variant #2 (Spectre): Mitigation: Full retpoline
CVE-2017-5715 - speculative execution branch target injection
   - Kernel with mitigation patches: OK
   - HW support / updated microcode: YES
   - IBRS: Not disabled on kernel commandline
   - IBPB: Not disabled on kernel commandline
   - Retpolines: Not disabled on kernel commandline

Variant #3 (Meltdown): Mitigation: PTI
CVE-2017-5754 - speculative execution permission faults handling
   - Kernel with mitigation patches: OK
   - PTI: Not disabled on kernel commandline

Note about virtualization
In virtualized environment, there are more steps to mitigate the issue, including:
* Host needs to have updated kernel and CPU microcode
* Host needs to have updated virtualization software
* Guest needs to have updated kernel
* Hypervisor needs to propagate new CPU features correctly
For more details about mitigations in virtualized environment see:
https://access.redhat.com/articles/3331571

For more information about the vulnerabilities see:
https://access.redhat.com/security/vulnerabilities/speculativeexecution

Thanks for the quick support :-).

If the script says "mitigation", you are fine. The kernel patches can only mitigate the vulnerability, because the real fix would need to be in the new HW generation. Also, if script returns 0, you have full mitigations for all the vulnerabilities. We are working on making it a bit easier to read.

Hi, as of today HPE has released new microcode firmware for the DL380 Gen7 platform. I've confirmed that updated the firmware properly, but the current check script, v2.3, is showing that Variant 2 is still Vulnerable. It's claiming that it can't detect without updated kernel, so is there another RHEL5 ELS kernel in the pipeline? The current script does show that Variant 1 and 3 are mitigated. Current kernel is 2.6.18-426.el5.

What is the ETA of variant 2 x86_64 for Red Hat Enterprise Linux 5 Extended Lifecycle Support?

Please note the last update of the script:

https://access.redhat.com/sites/default/files/spectre-meltdown--2018-04-13-1155.sh

cannot be downloaded, the link gives a 404 error.

Hi Does the script work correctly on rhel 7.5?

Yes, it does. I've just run the current version on a RHEL 7.5 machine.

Do any of these affect OLDER CPUs like the AMDs on bl465g6 or older inel xeonx like the ones in BL2x220G5?

Does anyone know if there is a changelog for the current version of the spectre-meltdown.sh script?

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