FPGA/EPLD Upgrade Procedure to Address Secure Boot Vulnerability

FPGA/EPLD Upgrade Precedure to Address Secure Boot Vulnerability

 

This document describes how to update the EPLD using the Generic EPLD update image for use with the Cisco Nexus 9000 Series switches and Cisco Nexus 3000 Series switches running 7.0(3)I4(x), 7.0(3)I7(1) to 7.0(3)I7(6) and 9.2(1) to 9.2(3) to address the Secure Boot Vulnerability detailed here. This EPLD update is a complimentary update to whatever EPLD software that shipped with the respective software, and hence can be additively applied to these versions. The update images are listed below and should be available against the ‘NX-OS EPLD Updates’ section of the latest maintenance release for each of the above trains.

■        For Cisco Nexus 9000 and 3000 Series switches - n9000-epld-secure-boot-update.img

For the affected switches mentioned in Table 1. Vulnerable Products addressed in Security Advisory (cisco-sa-20190513-secureboot)

Note: 9.3(1), 9.2(4) and 7.0(3)I7(7), will have this complimentary update built into their EPLD release update, and hence no need to apply this complimentary EPLD update. Please follow this link for N9K-C93180LC-EX

Table of Contents

Introduction   3

Deciding When to Upgrade EPLDs  3

Switch Requirements  3

EPLD Upgrades Available for NX-OS Mode Releases 7.0(3)I4(x) through 9.2(x)  5

Nexus 9000 Series Switches  5

Nexus 3000 Series Switches  6

Cisco Secure Boot Hardware Tampering Vulnerability - Remediation Steps  6

Downloading the EPLD Images  11

Installation Guidelines  12

Upgrading the EPLD Images  13

Verifying the EPLD Upgrades  13

Displaying the Status of EPLD Upgrades  13

Limitations  13

Related Documentation   13

Release Notes  14

Documentation Feedback  14

Obtaining Documentation and Submitting a Service Request  14

 

 

Introduction

The Cisco Nexus 9000 Series NX-OS mode switches contain several programmable logical devices (PLDs) that provide hardware functionalities in all modules. Cisco provides electronic programmable logic device (EPLD) image upgrades to enhance hardware functionality or to resolve known issues. PLDs include electronic programmable logic devices (EPLDs), field programmable gate arrays (FPGAs), and complex programmable logic devices (CPLDs), but they do not include ASICs. In this document, the term EPLD is used for FPGA and CPLDs.

The advantage of having EPLDs for some module functions is that when you need to upgrade those functions, you just upgrade their software images instead of replacing their hardware.

NOTE: EPLD image upgrades for a line card disrupt the traffic going through the module because the module must power down briefly during the upgrade. The system performs EPLD upgrades on one module at a time, so at any one time the upgrade disrupts only the traffic going through one module.

Cisco provides the latest EPLD images with each release. Typically, these images are the same as provided in earlier releases but occasionally some of these images are updated. These EPLD image updates are not mandatory unless otherwise specified. The EPLD image upgrades are independent from the Cisco In Service Software Upgrade (ISSU) process, which upgrades the system image with no impact on the network environment.

When Cisco makes an EPLD image upgrade available, these release notes announce their availability, and you can download the EPLD images from https://software.cisco.com/download/navigator.html.

Deciding When to Upgrade EPLDs

When new EPLD images are available, the upgrades are always recommended if your network environment allows for a maintenance period in which some level of traffic disruption is acceptable. If such a disruption is not acceptable, then consider postponing the upgrade until a better time.

NOTE: The EPLD upgrade operation is a disruptive operation. Execute this operation only at a programmed maintenance time.

NOTE: Do not perform an EPLD upgrade during an ISSU system upgrade.

Switch Requirements

The Cisco Nexus 9000 Series switch must be running the Cisco NX-OS operating system and include the following hardware:

■        Supervisor modules (2)—each with at least 800 MB of available boot flash memory (Cisco Nexus 9504, 9508, and 9516 switches)

■        System controller modules (2) (Cisco Nexus 9504, 9508, and 9516 switches)

■        Line cards (Cisco Nexus 9504, 9508, and 9516 switches)

—      Cisco Nexus 9504 switch (1 to 4 line cards)

—      Cisco Nexus 9508 switch (1 to 8 line cards)

—      Cisco Nexus 9516 switch (1 to 16 line cards)

■        Fabric modules (Cisco Nexus 9504, 9508, and 9516 switches)

—      Fabric modules for 40-Gigabit line cards on a Cisco Nexus 9504, 9508, or 9516 switch (3-6 modules)

—      Fabric modules for 100-Gigabit –E line cards on a Cisco Nexus 9504, 9508, or 9516 switch (4 modules)

—      Fabric modules for 100-Gigabit –S line cards on a Cisco Nexus 9504 or 9508 switch (4 modules)

■        Fan modules

—      Cisco Nexus 92304QC, 9272Q, and 93120TX switches (2 modules)

—      Cisco Nexus 9336C-FX2, 9364C, 9396PX, 9396TX, and 93128TX switches (3 modules)

—      Cisco Nexus 9236C, 92160YC-X, 92300YC, 9332PQ, 9372PX, 9372PX-E, 9372TX, 9372TX-E, 93108TC-EX, and 93180LC-EX switches (4 modules)

—      Cisco Nexus 9332C, and 93240YC-FX2 switch (5 modules)

—      Cisco Nexus 9504, 9508, and 9516 switches (3 fan trays)

■        Power supplies

—      500-W AC, 930-W DC, or 1200-W HVAC/HVDC power supplies (2 for the Cisco Nexus 93180LC-EX switches)

—      650-W AC, 930-W DC, or 1200-W HVAC/HVDC power supplies (2 for the Cisco Nexus 92160YC-X, 92304QC, 9236C, 93108TC-EX, 93180YC-EX, 9332PQ, 9372PX, 9372PX-E, 9372TX, 9372TX-E, 9396PX, and 9396TX switches

—      650-W AC or 1200-W HVAC/HVDC power supplies (2 for Cisco Nexus 92300YC switches)

—      930-W DC power supplies (2 for all Cisco Nexus 9200 and 9300 platform switches (except 92300YC and 9348GC-FXP switches)

—      11000W AC power supplies (2) for the Cisco Nexus 9332C, 9336C and 93240YC switches

—      11000W DC power supplies (2) for the Cisco Nexus 9332C, 9336C and 93240YC switches

—      11000W HVAC/HVDC power supplies (2) for the Cisco Nexus 9336C and 93240YC switches

—      1200-W AC power supplies (2) or 930-W DC power supplies (2) for the Cisco Nexus 9272Q, 93120TX, 93128TX, and 9364C switches

—      1200-W HVAC/HVDC power supplies (2) for all Cisco Nexus 9200 and 9300 platform switches (except the 9348GC-FXP switch)

—      3000-W AC power supplies or 3000-W Universal AC/DC or 3000-W DC power supplies for Cisco Nexus 9500 switches

—      3.15-kW dual input universal AC/DC power for the Cisco Nexus 9500 switches

- Cisco Nexus 9504 switch (up to 4)

- Cisco Nexus 9508 switch (up to 8)

- Cisco Nexus 9516 switch (up to 10)

■        Uplink module (Cisco Nexus 93128TX, 9396PX, and 9396TX switches only)

—      M4PC-CFP2

—      M6PQ

—      M6PQ-E

—      M12PQ

You must be able to access the switch through a console, SSH, or Telnet (required for setting up a switch running in NX-OS mode).

You must have administrator privileges to work with the Cisco Nexus 9000 Series switch.

EPLD Upgrades Available for NX-OS Mode Releases 7.0(3)I4(x) through 9.2(x)

Each EPLD image that you can download from https://software.cisco.com/download/navigator.html is a bundle of EPLD upgrades. To see the recent updated EPLD versions for the Cisco Nexus 9200, 9300, 9300-EX, 9300-FX, and 9500 platforms, see the following tables.

NOTE: All updates to an image are shown in boldface. If more than one release is shown for a column, the boldface applies to the first release listed for the column.

 

NOTE: The n9000-epld.secure-boot.img EPLD, addresses the Secure Boot Hardware Tampering vulnerability for the Nexus 3K and Nexus 9000 Series switches. Please refer to Security Advisory at https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190513-secureboot.

 

Please review the advisory for affected HW-PIDs (see below table) for more details on how to apply the patch. The n9000-epld.secure-boot.img epld requires a specific sequence of upgrade.

Table 1. Vulnerable Products addressed in Security Advisory (cisco-sa-20190513-secureboot)

Nexus 9000 Series Switches

 

NOTE: N3K-C36180YC-R and N3K-C3636C-R, CPU FPGA will have the fix, so look for CPU FPGA instead of IO.

Cisco Secure Boot Hardware Tampering Vulnerability - Remediation Steps

The following section details updating your EPLD version for affected switches listed in: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190513-secureboot

Nexus 9000 Modular chassis with dual supervisor:

 

IMPORTANT NOTE:
It is required to update both Golden and Primary regions of FPGA to address this particular vulnerability. It is by design, that we don't allow updating both primary and golden at the same time (to avoid programming errors, that may cause switch to not boot, hence only one region is allowed to be programmed per reload).

 

Please do not attempt to upgrade Golden region of FPGA once it is on a fixed version.

 

 

1. Copy the EPLD image to bootflash (e.g. used n9000-epld.secure-boot.img).

2. If you have dual supervisor, determine which is the standby Supervisor by doing 'show module' and start upgrading it first. On the N9K, Only supervisors need upgrade for this vulnerability. LC/FM/SC cards are not affected.

3. Assuming standby supervisor is slot 28. Update the Primary FPGA region of standby supervisor.

 

    install epld bootflash:n9000-epld.secure-boot.img module 28

 

Expected result: Switch will update primary EPLD of standby supervisor and will reload the standby supervisor module automatically. Please don't interrupt, power cycle or reload when EPLD update is happening. Once standby is booted, it will again come up as standby supervisor.  A 'show version module 28 epld' will continue to show old version.

 

switch# show mod | grep SUP

27   0    Supervisor Module                     N9K-SUP-A             active *

28   0    Supervisor Module                     N9K-SUP-A             ha-standby

27   9.3(0.416)               1.0    SUP1

28   9.3(0.416)               0.3011 SUP2

 

switch# show version module 28 epld

EPLD Device                     Version

---------------------------------------

IO FPGA                          0x27 

 

This is expected, as the switch would have booted from Golden FPGA which is still not updated. You can verify this from syslog which would say:

 

%CARDCLIENT-5-MOD_BOOT_GOLDEN: Module 28 IOFPGA booted from Golden

 

4. Update the Golden (also called backup) FPGA region of the standby supervisor.

 

install epld bootflash:n9000-epld.secure-boot.img module 28 golden[1]

 

Module 28 : IO FPGA [Programming      ] : 100.00% (     64 of      64 total sectors)

Module 28 EPLD upgrade is successful.

Module        Type  Upgrade-Result

------  ------------------  --------------

    28         SUP         Success 

 

Expected result: Switch will update the golden EPLD of standby supervisor and will reload the standby supervisor module automatically. Please don't interrupt, power cycle or reload when EPLD update is happening. Once standby is booted, it will again come up as ha-standby supervisor.

Once this is done, when you check 'show version module 28 epld' you will see FPGA version that is >= to the fixed version for the standby supervisor.  Your switch has the fixed version for standby supervisor. 

 

switch# show version module 28 epld

 

 

EPLD Device                     Version

---------------------------------------

IO FPGA                          0x30

 

Repeat Step 3 and  4, for the active supervisor. At the end of Step 3, supervisor in slot 27 will reload and hence now will become standby supervisor. The active supervisor will be Supervisor in slot 28. 

(considering SUP 27 is active to begin with, for the above activity, such as steps 3 and 4, commands would have 27 in place of 28.) 

 

Log below shows what happens when epld upgrade happens for active supervisor.

 

Module 27 : IO FPGA [Programming] : 100.00% (     64 of      64 sectors)

Module 27 EPLD upgrade is successful.

Module        Type  Upgrade-Result

------  ------------------  --------------

    27         SUP         Success

 

 

EPLDs upgraded. Performing switchover.

 

Once the supervisor in Slot 27 becomes ha-standby complete step 4 for Slot 27, and it will again boot and become ha-standby.  Both the supervisors now have the vulnerability fixed version of FPGA.

 

At the end of the upgrades, switch should boot with primary for both SUPs, logs below

 

switch# show logging log | grep -i fpga | grep -i 27

2019 Jul 10 07:55:04 switch %CARDCLIENT-5-MOD_BOOT_PRIMARY: Module 27 IOFPGA booted from Primary

switch# show logging log | grep -i fpga | grep -i 28

2019 Jul 10 07:58:01 switch %CARDCLIENT-5-MOD_BOOT_PRIMARY: Module 28 IOFPGA booted from Primary

 

Nexus 9000 Modular chassis with single supervisor:

 

IMPORTANT NOTE:
It is required to update both Golden and Primary regions of FPGA to address this particular vulnerability. It is by design, that we don't allow updating both primary and golden at the same time (to avoid programming errors, that may cause switch to not boot, hence only one region is allowed to be programmed per reload).

 

Please do not attempt to upgrade Golden region of FPGA once it is on a fixed version.

 

 

1. Copy the EPLD image to bootflash (e.g. used n9000-epld.secure-boot.img).

 

2. Assuming the supervisor is in Slot27. Update the Primary FPGA region.

 

install epld bootflash:n9000-epld.secure-boot.img module 27

 

Expected result: Primary EPLD of the supervisor will get upgraded and will cause a switch reload. Please don't interrupt, power cycle or reload when EPLD update is happening. Once the supervisor is booted, the 'show version module 27 epld' will continue to show old version

 

Switch#show version module 27 epld

-------------------------------------------------------------------

Name                     InstanceNum           Version        Date

-------------------------------------------------------------------

IO FPGA                          0              0x27       20160111

BIOS version                     v08.35(08/31/2018) 

Alternate BIOS version           v08.32(10/18/2016)

 

 

This is expected, as the switch would have booted from Golden FPGA which is still not updated. You can verify this from syslog which would say:

 

%CARDCLIENT-5-MOD_BOOT_GOLDEN: Module 27 IOFPGA booted from Golden

 

3. Since in this case there is only one supervisor, update the Golden (also called backup) FPGA region.

 

install epld bootflash:n9000-epld.secure-boot.img module 27 golden[2]

 

Module 27 : IO FPGA [Programming      ] : 100.00% (     64 of      64 total sectors)

Module 27 EPLD upgrade is successful.

Module        Type  Upgrade-Result

------  ------------------  --------------

    27         SUP         Success

 

 

Expected result: The golden EPLD of the supervisor will get upgraded and will cause a switch reload. Please don't interrupt, power cycle or reload when EPLD update is happening.

Once this is done, when you check ‘show version module 27 epld' you will see FPGA version that is >= to the fixed version for the supervisor. Your supervisor has the vulnerability fixed version of FPGA.

 

SWITCH# show version module 27 epld

-------------------------------------------------------------------

Name                     InstanceNum           Version        Date

-------------------------------------------------------------------

IO FPGA                          0              0x30       20190625

BIOS version                     v08.35(08/31/2018) 

Alternate BIOS version           v08.32(10/18/2016) 

 

At the end of the upgrades, switch should boot with primary for the SUP, log below

 

switch# show logging log | grep -i fpga | grep -i 27

2019 Jul 10 07:55:04 switch %CARDCLIENT-5-MOD_BOOT_PRIMARY: Module 27 IOFPGA booted from Primary

 

Nexus 9000 and Nexus 3000 TOR:

 

IMPORTANT NOTE:
It is required to update both Golden and Primary regions of FPGA to address this particular vulnerability. It is by design, that we don't allow updating both primary and golden at the same time (to avoid programming errors, that may cause switch to not boot, hence only one region is allowed to be programmed per reload).

 

Please do not attempt to upgrade Golden region of FPGA once it is on a fixed version.

 

 

1. Copy the EPLD image to bootflash (e.g. used n9000-epld.secure-boot.img).

2. Update the Primary FPGA region.

 

    install epld bootflash:n9000-epld.secure-boot.img module 1

 

 

Expected result: Switch will update EPLD and will reload automatically. Please don't interrupt, power cycle or reload when EPLD update is happening. Switch would boot up with golden FPGA, ‘show version module 1 epld’ would show the old Fpga version for IO, due to this. This is expected.

 

show version module 1 epld

-------------------------------------------------------------------

Name                     InstanceNum           Version        Date

-------------------------------------------------------------------

IO FPGA                          0              0x06       20180920

MI FPGA                          0              0x01       20170609

BIOS version                     v01.14(06/15/2019) 

Alternate BIOS version           v01.12(07/25/2018)

 

 

You can verify this from syslog which would say:

 

%CARDCLIENT-5-MOD_BOOT_GOLDEN: Module 1 IOFPGA booted from Golden

%CARDCLIENT-2-FPGA_BOOT_GOLDEN: IOFPGA booted from Golden

 

3. Update the Golden (also called backup) FPGA region.

 

    install epld bootflash:n9000-epld.secure-boot.img module 1 golden[3]

 

Expected result: Switch will update EPLD and will reload automatically. Please don't interrupt, power cycle or reload when EPLD update is happening.

 

Once this is done, when you check 'show version module 1 epld' you will see FPGA version that is >= to the fixed version. 

 

show version module 1 epld

-------------------------------------------------------------------

Name                     InstanceNum           Version        Date

-------------------------------------------------------------------

IO FPGA                          0              0x07      20190607

MI FPGA                          0              0x01       20170609

BIOS version                     v01.14(06/15/2019) 

Alternate BIOS version           v01.12(07/25/2018)

 

After upgrade is complete, switch should boot up with primary, shown logs below

 

show logging log | grep -i fpga

2019 Jul  9 19:46:11 switch %CARDCLIENT-2-FPGA_BOOT_PRIMARY: IOFPGA booted from Primary

2019 Jul  9 19:46:11 switch %CARDCLIENT-2-FPGA_BOOT_PRIMARY: MIFPGA booted from Primary

2019 Jul  9 19:46:11 switch %CARDCLIENT-5-MOD_BOOT_PRIMARY: Module 1 IOFPGA booted from Primary

2019 Jul  9 19:46:11 switch %CARDCLIENT-5-MOD_BOOT_PRIMARY: Module 1 MIFPGA booted from Primary

 

NOTE: For N3K-C36180YC-R and N3K-C3636C-R, CPU FPGA will have the fix, so look for CPU FPGA instead of IO.

 

 

Downloading the EPLD Images

Before you can prepare the EPLD images for installation, you must download them to the FTP or management server.

 

Installation Guidelines

To upgrade the EPLD images using CLI commands, follow these guidelines:

■        Before you upgrade any EPLD images, be sure that you have updated the Cisco NX-OS operating system to the level required for the images. Also be sure that you have an EPLD image file.

CAUTION: When you are trying to upgrade EPLD, it is recommended to use the same version of EPLD as that of installed software. However, if the installed version of EPLD is already later than the software you are installing, it is not required to downgrade the EPLD.

■        You can execute an upgrade from the active supervisor module only. This upgrade is for one or all of the modules as follows:

—      You can upgrade a module individually.

—      You can upgrade all modules sequentially.

—      You can update the images for online modules only.

■        On a Cisco Nexus 9500 platform switch that has two supervisor modules, upgrade the EPLDs for the standby supervisor and then switch the active supervisor to the standby mode to upgrade its EPLDs. The supervisor switchover is not disruptive to traffic on Cisco Nexus 9500 platform switches. On a switch that has only one supervisor module, you can upgrade the active supervisor, but this will disrupt its operations during the upgrade.

■        If you interrupt an upgrade, you must reapply the upgrade to the module that was being upgraded during the interruption.

■        The upgrade process disrupts traffic on the targeted module.

■        Do not insert or remove any modules while an EPLD upgrade is in progress.

 

Upgrading the EPLD Images

CAUTION: When you are trying to upgrade EPLD, it is recommended to use the same version of EPLD as that of installed software. However, if the installed version of EPLD is already later than the software you are installing, it is not required to downgrade the EPLD.

Verifying the EPLD Upgrades

To verify the EPLD upgrades for a switch or its modules, use the show version module slot-number epld command as follows:

■        To verify updates for a module on a modular switch (Cisco Nexus 9500 platform switches), indicate the chassis slot number for slot-number.
switch# show version module 27 epld

■        To verify updates for a top-of-rack switch (Cisco Nexus 9200, 9300, and 9300-EX platforms), use 1 for slot-number.
switch# show version module 1 epld

Displaying the Status of EPLD Upgrades

To display the status of EPLD upgrades on the switch, use the show install epld status command.

Limitations

When EPLDs are upgraded, the following guidelines and observations apply:

■        If a module is not online, you cannot upgrade its EPLD images.

■        If there are two supervisors that are installed in the switch (Cisco Nexus 9504, 9508, and 9516 switches only), you can either upgrade only the standby or upgrade all modules (including both supervisor modules) by using the following commands:

—      install epld bootflash: image module standby-supervisor-slot-number (upgrades only the standby supervisor module)

NOTE: After you use this command, you can switchover the active and standby supervisor modules and then upgrade the other supervisor.

—      install epld bootflash: image module all (upgrades all of the modules)

■        If there is only one supervisor that are installed in the switch, your upgrading or downgrading of EPLD images is disruptive.

Related Documentation

The entire Cisco NX-OS 9000 Series documentation set is available at the following URL: https://www.cisco.com/c/en/us/support/switches/nexus-9000-series-switches/tsd-products-support-series-home.html

Release Notes

The release notes are available at the following URL:
https://www.cisco.com/en/US/products/ps13386/prod_release_notes_list.html

Documentation Feedback

To provide technical feedback on this document, or to report an error or omission, please send your comments to nexus9k-docfeedback@cisco.com. We appreciate your feedback.

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