includes/shell/Shell.php

   1 <?php
   2 /**
   3  * Class used for executing shell commands
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 namespace MediaWiki\Shell;
  24
  25 use Hooks;
  26 use MediaWiki\MediaWikiServices;
  27
  28 /**
  29  * Executes shell commands
  30  *
  31  * @since 1.30
  32  *
  33  * Use call chaining with this class for expressiveness:
  34  *  $result = Shell::command( 'some command' )
  35  *       ->input( 'foo' )
  36  *       ->environment( [ 'ENVIRONMENT_VARIABLE' => 'VALUE' ] )
  37  *       ->limits( [ 'time' => 300 ] )
  38  *       ->execute();
  39  *
  40  *  ... = $result->getExitCode();
  41  *  ... = $result->getStdout();
  42  *  ... = $result->getStderr();
  43  */
  44 class Shell {
  45
  46         /**
  47          * Apply a default set of restrictions for improved
  48          * security out of the box.
  49          *
  50          * Equal to NO_ROOT | SECCOMP | PRIVATE_DEV | NO_LOCALSETTINGS
  51          *
  52          * @note This value will change over time to provide increased security
  53          *       by default, and is not guaranteed to be backwards-compatible.
  54          * @since 1.31
  55          */
  56         const RESTRICT_DEFAULT = 39;
  57
  58         /**
  59          * Disallow any root access. Any setuid binaries
  60          * will be run without elevated access.
  61          *
  62          * @since 1.31
  63          */
  64         const NO_ROOT = 1;
  65
  66         /**
  67          * Use seccomp to block dangerous syscalls
  68          * @see <https://en.wikipedia.org/wiki/seccomp>
  69          *
  70          * @since 1.31
  71          */
  72         const SECCOMP = 2;
  73
  74         /**
  75          * Create a private /dev
  76          *
  77          * @since 1.31
  78          */
  79         const PRIVATE_DEV = 4;
  80
  81         /**
  82          * Restrict the request to have no
  83          * network access
  84          *
  85          * @since 1.31
  86          */
  87         const NO_NETWORK = 8;
  88
  89         /**
  90          * Deny execve syscall with seccomp
  91          * @see <https://en.wikipedia.org/wiki/exec_(system_call)>
  92          *
  93          * @since 1.31
  94          */
  95         const NO_EXECVE = 16;
  96
  97         /**
  98          * Deny access to LocalSettings.php (MW_CONFIG_FILE)
  99          *
 100          * @since 1.31
 101          */
 102         const NO_LOCALSETTINGS = 32;
 103
 104         /**
 105          * Returns a new instance of Command class
 106          *
 107          * @param string|string[] $command String or array of strings representing the command to
 108          * be executed, each value will be escaped.
 109          *   Example:   [ 'convert', '-font', 'font name' ] would produce "'convert' '-font' 'font name'"
 110          * @return Command
 111          */
 112         public static function command( $command ) {
 113                 $args = func_get_args();
 114                 if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
 115                         // If only one argument has been passed, and that argument is an array,
 116                         // treat it as a list of arguments
 117                         $args = reset( $args );
 118                 }
 119                 $command = MediaWikiServices::getInstance()
 120                         ->getShellCommandFactory()
 121                         ->create();
 122
 123                 return $command->params( $args );
 124         }
 125
 126         /**
 127          * Check if this class is effectively disabled via php.ini config
 128          *
 129          * @return bool
 130          */
 131         public static function isDisabled() {
 132                 static $disabled = null;
 133
 134                 if ( is_null( $disabled ) ) {
 135                         if ( !function_exists( 'proc_open' ) ) {
 136                                 wfDebug( "proc_open() is disabled\n" );
 137                                 $disabled = true;
 138                         } else {
 139                                 $disabled = false;
 140                         }
 141                 }
 142
 143                 return $disabled;
 144         }
 145
 146         /**
 147          * Version of escapeshellarg() that works better on Windows.
 148          *
 149          * Originally, this fixed the incorrect use of single quotes on Windows
 150          * (https://bugs.php.net/bug.php?id=26285) and the locale problems on Linux in
 151          * PHP 5.2.6+ (bug backported to earlier distro releases of PHP).
 152          *
 153          * @param string $args,... strings to escape and glue together, or a single array of
 154          *     strings parameter. Null values are ignored.
 155          * @return string
 156          */
 157         public static function escape( /* ... */ ) {
 158                 $args = func_get_args();
 159                 if ( count( $args ) === 1 && is_array( reset( $args ) ) ) {
 160                         // If only one argument has been passed, and that argument is an array,
 161                         // treat it as a list of arguments
 162                         $args = reset( $args );
 163                 }
 164
 165                 $first = true;
 166                 $retVal = '';
 167                 foreach ( $args as $arg ) {
 168                         if ( $arg === null ) {
 169                                 continue;
 170                         }
 171                         if ( !$first ) {
 172                                 $retVal .= ' ';
 173                         } else {
 174                                 $first = false;
 175                         }
 176
 177                         if ( wfIsWindows() ) {
 178                                 // Escaping for an MSVC-style command line parser and CMD.EXE
 179                                 // Refs:
 180                                 //  * https://web.archive.org/web/20020708081031/http://mailman.lyra.org/pipermail/scite-interest/2002-March/000436.html
 181                                 //  * https://technet.microsoft.com/en-us/library/cc723564.aspx
 182                                 //  * T15518
 183                                 //  * CR r63214
 184                                 // Double the backslashes before any double quotes. Escape the double quotes.
 185                                 $tokens = preg_split( '/(\\\\*")/', $arg, -1, PREG_SPLIT_DELIM_CAPTURE );
 186                                 $arg = '';
 187                                 $iteration = 0;
 188                                 foreach ( $tokens as $token ) {
 189                                         if ( $iteration % 2 == 1 ) {
 190                                                 // Delimiter, a double quote preceded by zero or more slashes
 191                                                 $arg .= str_replace( '\\', '\\\\', substr( $token, 0, -1 ) ) . '\\"';
 192                                         } elseif ( $iteration % 4 == 2 ) {
 193                                                 // ^ in $token will be outside quotes, need to be escaped
 194                                                 $arg .= str_replace( '^', '^^', $token );
 195                                         } else { // $iteration % 4 == 0
 196                                                 // ^ in $token will appear inside double quotes, so leave as is
 197                                                 $arg .= $token;
 198                                         }
 199                                         $iteration++;
 200                                 }
 201                                 // Double the backslashes before the end of the string, because
 202                                 // we will soon add a quote
 203                                 $m = [];
 204                                 if ( preg_match( '/^(.*?)(\\\\+)$/', $arg, $m ) ) {
 205                                         $arg = $m[1] . str_replace( '\\', '\\\\', $m[2] );
 206                                 }
 207
 208                                 // Add surrounding quotes
 209                                 $retVal .= '"' . $arg . '"';
 210                         } else {
 211                                 $retVal .= escapeshellarg( $arg );
 212                         }
 213                 }
 214                 return $retVal;
 215         }
 216
 217         /**
 218          * Generate a Command object to run a MediaWiki CLI script.
 219          * Note that $parameters should be a flat array and an option with an argument
 220          * should consist of two consecutive items in the array (do not use "--option value").
 221          *
 222          * @param string $script MediaWiki CLI script with full path
 223          * @param string[] $parameters Arguments and options to the script
 224          * @param array $options Associative array of options:
 225          *     'php': The path to the php executable
 226          *     'wrapper': Path to a PHP wrapper to handle the maintenance script
 227          * @return Command
 228          */
 229         public static function makeScriptCommand( $script, $parameters, $options = [] ) {
 230                 global $wgPhpCli;
 231                 // Give site config file a chance to run the script in a wrapper.
 232                 // The caller may likely want to call wfBasename() on $script.
 233                 Hooks::run( 'wfShellWikiCmd', [ &$script, &$parameters, &$options ] );
 234                 $cmd = isset( $options['php'] ) ? [ $options['php'] ] : [ $wgPhpCli ];
 235                 if ( isset( $options['wrapper'] ) ) {
 236                         $cmd[] = $options['wrapper'];
 237                 }
 238                 $cmd[] = $script;
 239
 240                 return self::command( $cmd )
 241                         ->params( $parameters )
 242                         ->restrict( self::RESTRICT_DEFAULT & ~self::NO_LOCALSETTINGS );
 243         }
 244 }