MediaWiki  master
FirejailCommand.php
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1 <?php
21 namespace MediaWiki\Shell;
22 
24 
31 class FirejailCommand extends Command {
32 
36  private $firejail;
37 
41  private $whitelistedPaths = [];
42 
46  public function __construct( $firejail ) {
47  parent::__construct();
48  $this->firejail = $firejail;
49  }
50 
54  public function whitelistPaths( array $paths ): Command {
55  $this->whitelistedPaths = array_merge( $this->whitelistedPaths, $paths );
56  return $this;
57  }
58 
62  protected function buildFinalCommand( $command ) {
63  // If there are no restrictions, don't use firejail
64  if ( $this->restrictions === 0 ) {
65  $splitCommand = explode( ' ', $command, 2 );
66  $this->logger->debug(
67  "firejail: Command {$splitCommand[0]} {params} has no restrictions",
68  [ 'params' => $splitCommand[1] ?? '' ]
69  );
70  return parent::buildFinalCommand( $command );
71  }
72 
73  if ( $this->firejail === false ) {
74  throw new RuntimeException( 'firejail is enabled, but cannot be found' );
75  }
76  // quiet has to come first to prevent firejail from adding
77  // any output.
78  $cmd = [ $this->firejail, '--quiet' ];
79  // Use a profile that allows people to add local overrides
80  // if their system is setup in an incompatible manner. Also it
81  // prevents any default profiles from running.
82  // FIXME: Doesn't actually override command-line switches?
83  $cmd[] = '--profile=' . __DIR__ . '/firejail.profile';
84 
85  // By default firejail hides all other user directories, so if
86  // MediaWiki is inside a home directory (/home) but not the
87  // current user's home directory, pass --allusers to whitelist
88  // the home directories again.
89  static $useAllUsers = null;
90  if ( $useAllUsers === null ) {
91  global $IP;
92  // In case people are doing funny things with symlinks
93  // or relative paths, resolve them all.
94  $realIP = realpath( $IP );
95  $currentUser = posix_getpwuid( posix_geteuid() );
96  $useAllUsers = ( strpos( $realIP, '/home/' ) === 0 )
97  && ( strpos( $realIP, $currentUser['dir'] ) !== 0 );
98  if ( $useAllUsers ) {
99  $this->logger->warning( 'firejail: MediaWiki is located ' .
100  'in a home directory that does not belong to the ' .
101  'current user, so allowing access to all home ' .
102  'directories (--allusers)' );
103  }
104  }
105 
106  if ( $useAllUsers ) {
107  $cmd[] = '--allusers';
108  }
109 
110  if ( $this->whitelistedPaths ) {
111  // Always whitelist limit.sh
112  $cmd[] = '--whitelist=' . __DIR__ . '/limit.sh';
113  foreach ( $this->whitelistedPaths as $whitelistedPath ) {
114  $cmd[] = "--whitelist={$whitelistedPath}";
115  }
116  }
117 
118  if ( $this->hasRestriction( Shell::NO_LOCALSETTINGS ) ) {
119  $cmd[] = '--blacklist=' . realpath( MW_CONFIG_FILE );
120  }
121 
122  if ( $this->hasRestriction( Shell::NO_ROOT ) ) {
123  $cmd[] = '--noroot';
124  }
125 
126  $useSeccomp = $this->hasRestriction( Shell::SECCOMP );
127  $extraSeccomp = [];
128 
129  if ( $this->hasRestriction( Shell::NO_EXECVE ) ) {
130  $extraSeccomp[] = 'execve';
131  // Normally firejail will run commands in a bash shell,
132  // but that won't work if we ban the execve syscall, so
133  // run the command without a shell.
134  $cmd[] = '--shell=none';
135  }
136 
137  if ( $useSeccomp ) {
138  $seccomp = '--seccomp';
139  if ( $extraSeccomp ) {
140  // The "@default" seccomp group will always be enabled
141  $seccomp .= '=' . implode( ',', $extraSeccomp );
142  }
143  $cmd[] = $seccomp;
144  }
145 
146  if ( $this->hasRestriction( Shell::PRIVATE_DEV ) ) {
147  $cmd[] = '--private-dev';
148  }
149 
150  if ( $this->hasRestriction( Shell::NO_NETWORK ) ) {
151  $cmd[] = '--net=none';
152  }
153 
154  $builtCmd = implode( ' ', $cmd );
155 
156  // Prefix the firejail command in front of the wanted command
157  return parent::buildFinalCommand( "$builtCmd -- {$command}" );
158  }
159 
160 }
$IP
Definition: WebStart.php:41
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
const NO_ROOT
Disallow any root access.
Definition: Shell.php:52
hasRestriction( $restriction)
Bitfield helper on whether a specific restriction is enabled.
Definition: Command.php:263
const MW_CONFIG_FILE
Definition: bootstrap.php:53
string $firejail
Path to firejail.
Class used for executing shell commands.
Definition: Command.php:36
const NO_LOCALSETTINGS
Deny access to LocalSettings.php (MW_CONFIG_FILE)
Definition: Shell.php:90
this hook is for auditing only or null if authentication failed before getting that far or null if we can t even determine that When $user is not null
Definition: hooks.txt:767
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:9
const NO_EXECVE
Deny execve syscall with seccomp.
Definition: Shell.php:83
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
const SECCOMP
Use seccomp to block dangerous syscalls.
Definition: Shell.php:60
const NO_NETWORK
Restrict the request to have no network access.
Definition: Shell.php:75
Restricts execution of shell commands using firejail.
const PRIVATE_DEV
Create a private /dev.
Definition: Shell.php:67
Copyright (C) 2017 Kunal Mehta legoktm@member.fsf.org
Definition: Command.php:21