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TimesysGit / vigiles-buildroot

Vulnerability management tool that provides Buildroot SBOM generation and CVE Analysis of target images.
https://www.timesys.com/vigiles/
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buildroot buildroot-cve buildroot-cve-analysis buildroot-sbom buildroot-security cve cve-scanning linux-security spdx-sbom

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Timesys Vigiles

Timesys Vigiles For Buildroot

This is a collection of tools for image SBOM generation used for security monitoring and notification as part of the Timesys Vigiles product offering.

What is Vigiles?

Vigiles is a vulnerability management tool that provides build-time CVE Analysis of Buildroot target images. It does this by collecting metadata about packages to be installed and uploading it to be compared against the Timesys CVE database.A high-level overview of the detected vulnerabilities is returned and a full detailed analysis can be viewed online.

Register (free) and download the API key to access the full feature set based on Vigiles Basic, Plus or Prime: https://linuxlink.timesys.com/docs/wiki/engineering/LinuxLink_Key_File

Requirements

Note: Support for CPE_ID variables was introduced in buildroot from version 2021.02, therefore for versions before that vigiles-buildroot will set the cpe_id variable to "UNKNOWN"

Installation

  1. Clone vigiles-buildroot repository at the same level as Buildroot directory.

    git clone https://github.com/TimesysGit/vigiles-buildroot

  2. Install dependencies

    python3 -m pip install -r vigiles-buildroot/requirements.txt

Setup

  1. Download your LinuxLink Key File here and store it at the (recommended) path.

    mkdir $HOME/timesys
cp $HOME/Downloads/linuxlink_key $HOME/timesys/linuxlink_key

    Note: If the key is stored elsewhere, the location can be specified via the Buildroot configuration interface.

    See below for instructions.

  2. Instruct Buildroot to include the Vigiles interface in its configuration.

    make BR2_EXTERNAL=/path/to/vigiles-buildroot menuconfig

    Note: If you are already using an external Buildroot tree/interface, multiple paths can be concatenated, e.g.:

      make BR2_EXTERNAL=/path/to/other/external/buildroot/interface:/path/to/vigiles-buildroot menuconfig

    For more information on using external Buildroot interfaces, please see This Section of the Buildroot Documentation

Generating SBOM only

Generating SBOM only option can be found under the Advanced Vigiles option in the menuconfig interface

                *** Advanced Vigiles / Debug Options ***
        [*]   Generate SBOM only

This option will only generate the SBOM. By default the generated SBOM is also uploaded to vigiles for a vulnerability scan. Set an environment variable GENERATE_SBOM_ONLY to True or False to override the current setting in the menuconfig.

Using Vigiles CVE Check

To generate a vulnerability report follow the below steps:

  1. Execute Make with the Vigiles target

    make vigiles-check

  2. View the Vigiles CVE (Text) Report Locally

    The CVE report will be located in the vigiles/ subdirectory of your Buildroot build output, with a name based on the Target configuration; e.g.:

    wc -l output/vigiles/buildroot-imx8mpico-report.txt
    3616 output/vigiles/buildroot-imx8mpico-report.txt

  3. View the Vigiles CVE Online Report

    The local CVE text report will contain a link to a comprehensive and graphical report; e.g.:

    -- Vigiles CVE Report --
        View detailed online report at:
          https://linuxlink.timesys.com/cves/reports/< Unique Report Identifier>

    The CVE SBOM

    The Vigiles CVE Scanner creates a SBOM that it sends to the LinuxLink Server describing your build configuration. This SBOM is located in the vigiles/ subdirectory of your Buildroot output (the same location as the text report it receives back).

    wc -l output/vigiles/buildroot-imx8mpico-manifest.json 
    557 output/vigiles/buildroot-imx8mpico-manifest.json

    In the event that something goes wrong, or if the results seem incorrect, this file may offer insight as to why. It's important to include this file with any support request.

Configuration

If included, Timesys Vigiles will be enabled by default with the Kconfig option BR2_EXTERNAL_TIMESYS_VIGILES. In addition, there are other configuration options available to control the behavior of the subsystem.

Note About Pathnames

Pathnames that are specified follow the same semantics as throughout the Buildroot build system

  • Non-absolute paths are relative to the top of the Buildroot source.

  • Variables from both the shell and make environments are accessible using 'make' syntax; e.g. $(HOME), $(BUILD_DIR), $(TOPDIR)

  • Shell expansion is not available; i.e. ~/ will not reference a user's home directory. Use $(HOME)/ instead.

Base Configuration

Using make menuconfig, the Vigiles configuration menu can be found under External Options.

External options  ---> 
    *** Timesys Vigiles CVE Checker (in /home/mochel/projects/buildroot/vigiles) ***
    [*] Enable Timesys Vigiles CVE Check  --->

Reporting and Filtering

Linux Kernel and U-Boot .config filtering can be enabled/disabled using the options VIGILES_ENABLE_KERNEL_CONFIG and VIGILES_ENABLE_UBOOT_CONFIG.

If using a custom location for either the Kernel or U-Boot .config files, the paths can be specified using BR2_EXTERNAL_VIGILES_KERNEL_CONFIG and BR2_EXTERNAL_VIGILES_UBOOT_CONFIG.

The default for both paths is auto which results in automatically using the .config from the package's configured build directory. It is recommended that this value is used unless it is absolutely necessary to specify an alternative path.

              *** Vigiles Kernel CVE Reporting Options ***
        [*]   Enable Linux Kernel .config Filtering
        (auto)  Location of Linux Kernel .config file
        [*]   Enable U-Boot .config Filtering
        (auto)  Location of U-Boot .config file

Note:

Linux Kernel .config filtering is only enabled if Kernel ---> [*] Linux Kernel (BR2_LINUX_KERNEL) is enabled.

U-Boot .config filtering is enabled only if Bootloaders ---> [*] U-Boot (BR2_TARGET_UBOOT) is enabled.

Customizing / Amending the Vigiles Report

In some cases, it's desirable to modify the CVE report that Vigiles generates. vigiles-buildroot supports the ability to Include Additional Packages, Exclude Packages and Whitelist Known CVEs. In addition, the file names of the locally-generated SBOM and CVE Report may be customized.

All of these options are supported by a Kconfig option where a user may specify a CSV (comma-separated-value) file that describe the packages or CVEs. Each is described below.

SBOM and Report Naming

By default, the file names of the Vigiles SBOM to be uploaded and the CVE Report that is generated are given names based on the values of BR2_HOSTNAME and BR2_DEFCONFIG (or the target CPU), which will produce files like this:

output/vigiles
├── buildroot-nitrogen6x-manifest.json
└── buildroot-nitrogen6x-report.txt

To use a custom name for the local Vigiles SBOM that is uploaded and the CVE Report that is generated, the Kconfig option BR2_EXTERNAL_VIGILES_MANIFEST_NAME can be used. If set to 'Custom-Name', the files produced will be:

output/vigiles
├── Custom-Name-manifest.json
└── Custom-Name-report.txt

Including Additional Packages

To include packages that are built outisde of the standard Buildroot process (and therefore wouldn't be included in the Vigiles CVE Report), the Kconfig option BR2_EXTERNAL_VIGILES_INCLUDE_CSV ("Additional Packages to Include in Report") may be set to the path of a CSV file.

Example: $(HOME)/projects/buildroot/vigiles-additional-packages.csv

The CSV file consists of an optional header and the following fields:

The following example shows the accepted syntax for expressing extra packages:

$ cat $HOME/projects/buildroot/vigiles-additional-packages.csv
product,version,license
avahi,0.6
bash,4.0
bash,4.1,GPL 3.0
busybox,
udev,,"GPLv2.0+, LGPL-2.1+"

Excluding Packages

In some cases, a more condensed CVE Report may be desired, so a list of specific packages to omit may be specified (for example: packages that only install data files).

To exclude packages from the CVE Report, the Kconfig option BR2_EXTERNAL_VIGILES_EXCLUDE_CSV may be set to the path of CSV file.

Example: $(HOME)/projects/buildroot/vigiles-exclude-packages.csv

The CSV file expects one package name per line. Any additional CSV fields are ignored.

For example:

$ cat $HOME/projects/buildroot/vigiles-exclude-packages.csv
linux-libc-headers
opkg-utils
packagegroup-core-boot

Whitelisting CVEs

Some packages may have CVEs associated with them that are known to not affect a particular machine or configuration. Buildroot packages may express these in their respective Makefiles via the IGNORE_CVES variable. However, there may be additional CVEs to ignore/whitelist.

A user may set the Kconfig option BR2_EXTERNAL_VIGILES_WHITELIST_CSV to the path of a CSV file containing a list of CVEs to omit from the Vigiles Report.

Example: $(HOME)/projects/buildroot/vigiles-cve-whitelist.csv

The CSV expects one CVE ID per line. Any additional fields will be ignored.

For example:

$ cat $HOME/projects/buildroot/vigiles-cve-whitelist.csv

Uploading the SBOM (Only)

In some cases, it may be desired to upload the Vigiles SBOM for a build without generating a CVE Report. This can speed up build times and ease reporting of automated bulk builds.

This behavior can be enabled with the Kconfig option BR2_EXTERNAL_VIGILES_UPLOAD_ONLY.

Instead of a text report and a link to the online report, a link to the Vigiles Dashboard Product Workspace (as specified with VIGILES_DASHBOARD_CONFIG) will be displayed, from where it can be then be scanned by the Vigiles Service.

LinuxLink Credentials

To specify an alternative location for the Timesys LinuxLink Key File, (default: $(HOME)/timesys/linuxlink_key) it can be set with the string BR2_EXTERNAL_VIGILES_KEY_FILE.

               *** Timesys LinuxLink Account Options ***
        ($(HOME)/timesys/linuxlink_key) Timesys LinuxLink Key Location

Whether the default is used, or if this Kconfig option is set, it will be overridden by the environment variable VIGILES_KEY_FILE. A developer may set this on the command line to use a personal/local key without having to change a shared defconfig for a board.

Vigiles Dashboard Configuration

A custom LinuxLink Dashboard configuration can be set by first enabling VIGILES_ENABLE_DASHBOARD_CONFIG and specifying the path in the string BR2_EXTERNAL_VIGILES_DASHBOARD_CONFIG. If unset, a default path will be used ($(HOME)/timesys/dashboard_config)

                *** Timesys Vigiles Dashboard Options ***
         [*]   Use a custom Vigiles Dashboard Configuration
         ($(HOME)/timesys/dashboard_config) Timesys Vigiles Dashboard Config Location

Whether the default is used, or if this Kconfig option is set, it will be overridden by the environment variable VIGILES_DASHBOARD_CONFIG. A developer may set this on the command line to use their personal/private Dashboard settings.

By default your SBOM will be uploaded to your "Private Workspace" Product on the Vigiles Dashboard. This can be changed by downloading the "Dashboard Config" for an alternative Product and/or Folder.

Dashboard Config files will be downloaded by default to e.g. "${HOME}/Downloads/<product name>_<folder name>_config". Once moving and/or renaming it as necessary, you can control the behavior of Vigiles for Buildroot by setting the config variable above.

New Products can be defined by clicking on the "New Product" product link and specifying a name. To download the Dashboard Config for the top-level folder of that Product, click on the "Product Settings" link and you will see a preview of the dashboard config file. You can copy the contents and create the file for yourself or choose to download it with the buttons on the right.

Once a new product is created, sub-folders may be created by clicking on the "Create Folder" and specifying a name. The Dashboard Config for that Folder (in that Product) may be downloaded by first clicking on/opening the Folder, then clicking the "Folder Settings" link and choosing to copy or download the config for that folder.

Dynamic subfolder creation

               --- Enable Timesys Vigiles CVE Check
               *** Vigiles Kernel CVE Reporting Options ***
               *** Customizing / Amending Vigiles Report ***
         ()    Custom SBOM and Report Name
         ()    Subfolder name

If a Dashboard Config is used, a subfolder name can be specified for dynamic folder creation. SBOMs will be uploaded to a subfolder with this name within the location specified in the Dashbord Config. If one does not exist, it will be created. This option will be overridden by the environment variable VIGILES_SUBFOLDER_NAME

Advanced Options

For development purposes, some "Expert" options are available by first enabling VIGILES_ENABLE_EXPERT. These allow for debugging of the metadata that is collected.

These features are not supported and no documentation is provided for them.

               *** Advanced Vigiles / Debug Options ***
        [*]   Enable Vigiles Advanced and Debugging Options (Expert)
        [ ]   Enable Verbose Console Output
        [ ]     Write Intermediate JSON Files of Collected Metadata
        [ ]   Include virtual packages in SBOM
        ()    Vigiles output location
        [ ]   Generate SBOM only (NEW)

Including Virtual Packages in generated SBOM

This option can be found under Advanced Vigiles option

                *** Advanced Vigiles / Debug Options ***
        [ ]   Include virtual packages in SBOM

This option will include the virtual packages in generated SBOM. By default vigiles-buildroot will exclude the virtual packages from generated SBOM.

Specifying location for Vigiles output

This option can be found under Advanced Vigiles option

                *** Advanced Vigiles / Debug Options ***
        ()   Vigiles output location

This option specifies the location of the vigiles output files like SBOM, report and vigiles logs. The default location is <buildroot>/output/vigiles directory. Environment variable VIGILES_OUTPUT_DIR can be used to override this config.

Specifying SBOM formats

This option can be found under Advanced Vigiles option

        Select SBOM format -->

This option can be used to specify the format of SBOM to be generated. At present vigiles-buildroot supports generating SBOMs in Cyclonedx 1.4 JSON and Vigiles JSON formats. By default, Vigiles JSON format SBOM will be generated.

Required Files check

Vigiles-buildroot parses .config and .hash files for package dependencies and checksums. User can set Require all config files and Require all config files options in menuconfig to raise an error if any file is missing. By default, vigiles-buildroot will only show a warning message if any of these files is missing.

        ...
        [*]   Require all config files
        [*]   Require all hashfiles

Other Notes

Make 4.3 Workaround

The version of make that was shipped with Ubuntu 22.04 contains a bug that is described here:

https://savannah.gnu.org/bugs/?59093

It is discussed in this Buildroot thread:

https://git.buildroot.org/buildroot/commit/?id=5a9504831f3fa1ef3be334036c93da30150fde55

Unfortunately, this prevents Vigiles-Buildroot from working as it inherently depends on the make printvars command.

In order to enable Vigiles functionality, we had to engage a very 'special' strategy if and only if Make 4.3 is detected by which (a) we inhibit the Buildroot workaround (by using a fixed-up top-level Makefile ONLY FOR THAT CALL); and (b) execute make printvars with an increased process stack size (by wrapping it with prlimit)

Should this interfere with one's build system, an alternative approach can be used, though it will require custom modifications to both vigiles-buildroot and Buildroot itself.

Please note that this approach is not officially supported and YMMV.

Package Version Information in Generated SBOM

Buildroot includes packages/config scripts lacking version information (Ex. initscripts, urandom-scripts, etc.). In the generated SBOM for such packages version is set to the Buildroot version or the Buildroot commit hash.

Setting CPE ID variables

Buildroot allows to define a set of variables in package's makefile (<package-name>.mk), to specify its CPE identifier. For instance, in the case of the busybox package, these variables such as product, version, vendor, etc. can be set in busybox.mk as below

BUSYBOX_CPE_ID_PRODUCT = busybox
BUSYBOX_CPE_ID_VERSION = 1.36.1
BUSYBOX_CPE_ID_VENDOR = busybox

The vigiles-buildroot uses these variables to generate a cpe id if it is not already specified

Maintenance

The Vigiles CVE Scanner and Buildroot support are maintained by The Timesys Security team.

For Updates, Support and More Information, please see:

Vigiles Website

and

vigiles-buildroot @ GitHub