Code auditing

Using Exakat with Docker

Posted on by dams

Using Exakat with Docker

Exakat is available on docker, as community version. It is available at hub.docker.com. Here is how to use it.

Installation

docker is needed to run this tutorial.

To install exakat, start docker, then run the following command in the terminal :

git pull exakat/exakat:latest

With a graphical interface, such as Docker Desktop, in the ‘images’ entry, use the ‘remote repositories’ to load a remote image.

This is the latest exakat version, 2.4.0 at the time of writing this tutorial. The fixed version is also available with the 2.4.0tag.

The image uses the last PHP version available, PHP 8.1.8 at the time of writing. A PHP 8.0 version is also available.

Finally, Exakat is also build for AMD (Intel processor) or ARM (Apple M1). It is possible to choose among those version with the following format :

exakat/exakat-<php>-<platform>:tag.

  • tag : latest, 2.4.0
  • php : 81, 80
  • platform : amd64, arm64

For example, git pull exakat/exakat-81-arm64:latestis the latest version for Apple M1 computers. In the rest of the tutorial, we’ll use exakat/exakat:latest as image, and you may use any downloaded image instead in the commands.

Checking the image

Before running an audit, let’s check if the installation is correct. Run the following command :

docker run -it --rm exakat/exakat:latest

This is the default command, which prints the version of Exakat. The results should look list this :

 ________                 __              _    
|_   __  |               [  |  _         / |_  
  | |_ \_| _   __  ,--.   | | / ]  ,--. `| |-' 
  |  _| _ [ \ [  ]`'_\ :  | '' <  `'_\ : | |   
 _| |__/ | > '  < // | |, | |`\ \ // | |,| |,  
|________|[__]`\_]\'-;__/[__|  \_]\'-;__/\__/  
                                               

Exakat : @ 2014-2022 Damien Seguy - Exakat SAS <contact(at)exakat.io>. 
Version : 2.4.0 - Build 1312 - Wed, 20 Apr 2022 14:54:25 +0200

You may also run the doctor command, to review the default installation config :

docker run -it --rm exakat/exakat:latest doctor

Here is a result :

exakat : 
    executable           : ./exakat
    version              : 2.4.0
    build                : 1312
    exakat.ini           : ./config/exakat.ini
    graphdb              : gsneo4jv3
    reports              : 
    rulesets             : CompatibilityPHP74,
                           CompatibilityPHP80,
                           CompatibilityPHP81,
                           Analyze,
                           Appinfo
    extra rulesets       : 
    ignored rules        : 
    tokenslimit          : 100 000 000
    stubs                : 

PHP : 
    binary               : 8.1.8
    memory_limit         : -1
    short_open_tags      : Off
    ext/curl             : Yes
    ext/hash             : Yes
    ext/phar             : Yes
    ext/sqlite3          : Yes
    ext/tokenizer        : Yes
    ext/mbstring         : Yes
    ext/json             : Yes
    ext/xmlwriter        : Yes
    pcre.jit             : On (Must be off on PHP 7.3 and OSX)

java : 
    installed            : Yes
    type                 : OpenJDK Runtime Environment 18.9 (build 11.0.16+8)
    version              : openjdk
    $JAVA_HOME           : /usr/local/openjdk-11
    $JAVA_OPTIONS        : 

tinkergraph : 
    installed            : Yes (folder : /usr/src/exakat/tinkergraph)
    host                 : 127.0.0.1
    port                 : 7474
    gremlin version      : 3.4.13

tinkergraphv3 : 
    installed            : Yes (folder : /usr/src/exakat/tinkergraph)
    host                 : 127.0.0.1
    port                 : 7474
    gremlin version      : 3.4.13

gsneo4j : 
    installed            : No (folder : tinkergraph)

gsneo4jv3 : 
    installed            : Yes (folder : /usr/src/exakat/tinkergraph)
    host                 : 127.0.0.1
    port                 : 8182
    gremlin version      : 3.4.13
    neo4j version        : 3.2.3

nogremlin : 
    installed            : Always

project : 
    name                 : 
    url                  : 
    phpversion           : 7.4
    reports              : "Diplomat"
    rulesets             : CompatibilityPHP74, CompatibilityPHP80, CompatibilityPHP81, Analyze, Appinfo
    included dirs        : 
    ignored dirs         : /assets, /cache, /css, /data, /doc, /docker, /docs, /example, /examples, /images, /js, /lang, /spec, /sql, /test, /tests, /tmp, /version, /var
    ignored rules        : 
    file extensions      : php, php3, inc, tpl, phtml, tmpl, phps, ctp, module

folders : 
    projects folder      : Yes

php81 : 
    configured           : Yes (/usr/bin/php)
    actual version       : 8.1.8

We can check that PHP 8.1, Java 11 and Exakat 2.4.0 are all installed. So far, so good.

First audit

To run a first audit, we need source code. We are going to use the following Git repository, for the purpose of testing : https://github.com/zordius/lightncandy.git. It is a public package, from Zordius, which makes handlebars.

To run the audit, use the following project command :

docker run -it --rm  exakat/exakat:latest project -p zordius -R https://github.com/zordius/lightncandy.git --format Text

While it runs, here are some explanations :

  • -p is the project name. It is a compulsory argument for exakat. Here, it is a free string.
  • -R is the URI to the repository. It is compulsory with the init command. The format of the value depends on the VCS in use. Here, it is a URL, while it would be a package handle with composer.
  • -git has been omitted here, as it is the default option. Other VCS are supported, such as -composer or -svn.
  • --format provides the format of the audit. It is Text here, so the audit is exported to the STDOUT, in Text format, one issue per line. There are other format which outputs results to the STDOUT. Other possible format here, are JSON, Perfile Sarif or Perrule.

Once the audit has run, it will provide results similar to this :

/src/Encoder.php:84 Type/OneVariableStrings One Variable String $v
/src/Encoder.php:101    Functions/UndefinedFunctions    Undefined Functions htmlspecialchars(static::raw($cx, $var), ENT_QUOTES, 'UTF-8')
/src/Encoder.php:101    Constants/UndefinedConstants    Undefined Constants ENT_QUOTES
/src/Encoder.php:101    Constants/ConstantUsage Constants Usage ENT_QUOTES
/src/Encoder.php:119    Functions/UndefinedFunctions    Undefined Functions str_replace(array('=', '`', '&#039;'), array('&#x3D;', '&#x60;', '&#x27;'), htmlspecialchars(static::raw($cx, $var), ENT_QUOTES, 'UTF-8'))
/src/Encoder.php:119    Functions/UndefinedFunctions    Undefined Functions htmlspecialchars(static::raw($cx, $var), ENT_QUOTES, 'UTF-8')
/src/Encoder.php:119    Constants/UndefinedConstants    Undefined Constants ENT_QUOTES
/src/Encoder.php:119    Constants/ConstantUsage Constants Usage ENT_QUOTES
/src/Encoder.php:70 Functions/UndefinedFunctions    Undefined Functions array_diff_key($v, array_keys(array_keys($v)))
/src/Encoder.php:70 Functions/UndefinedFunctions    Undefined Functions array_keys(array_keys($v))
/// ..... more lines

Second audit

The first audit provides results to STDOUT, the terminal screen. Exakat offers several other formats, which are saved as files. Since those would be lost at the end of the run of the image, we need to adapt the command to keep the results.

docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest project -p zordius -R https://github.com/zordius/lightncandy.git

This time, Exakat runs and share a folder called projects, where the intermediate results are stored. While it runs, here are some details :

  • -v is a docker option, which maps a host machine folder (here the projects folder, in the current directory), to a folder in the docker container, where the audits and various files will be stored.
  • --format was removed, as the command produces the Diplomatreport, by default. We’ll see some other format later.

After the run, you should find a local folder called projects. In it, you’ll find a folder called zordius, and, yet again, in it, several files and folder. Open the one called diplomat, and the file index.htmlwith a web browser. You should get the result of the audit.

Producing more reports

One advantage of saving the results is the possibility to produce more reports, using a different format.

The following report command produce the same report as the first audit, without running the audit again : it relies on the results that were produced by the previous step. For a repeat, or a specific extraction, this is a lot faster as all is cached.

docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest report -p zordius --format Text

The following report provides the same results, grouped by file.

docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest report -p zordius --format Perfile

List of reports and rulesets

All the availables rules, rulesets and reports in the current Exakat version are listed with the catalog command :

docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest catalog

The full list, including the extra availables in the Enterprise version of Exakat is online, in the documentation.

Next steps

Rerun the audit on updated code

With a locally saved report, exakat may update the source, and run the audit again. Use the following commands :

docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest update -p zordius 
docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest update -p zordius

The update command only works with a saved report : with a direct projectcommand, the code is cloned again, so there is no need for update.

The resulting audit will be replaced with a new one. Save it before starting the new audit if you want to compare them later.

Run another saved audit

To run an audit on another code, use the commands from the Second auditsection, with a different URL and project name. They will all be stored in the projects folders.

Extract only some results

By default, the Text report exports a preset list of rules. If you want focus on one specific ruleset, you can use the -T option. Here is the command with the Security ruleset.

docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest report -p zordius --format Text -T Security

Here is the command with one specific rule : Structures/NoParenthesisForLanguageConstruct. This rule checks if parenthesis are used with language constructs, such as include_once : they are useless.

docker run -it --rm  -v `pwd`/projects:/usr/src/exakat/projects/ exakat/exakat:latest report -p zordius --format Text -P Php\BetterRand

The names of Rulesets and Rules are available in the documentation of the Diplomat report, or online.

Happy auditing!

Docker installation is convenient as it hides the complexity of the installation. The audit results are quick to obtain, and it is now time to review what was found.