├── COPYING ├── README.md ├── formats.md └── src └── PhpSessionSerializer.php /COPYING: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 2, June 1991 3 | 4 | Copyright (C) 1989, 1991 Free Software Foundation, Inc., 5 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 6 | Everyone is permitted to copy and distribute verbatim copies 7 | of this license document, but changing it is not allowed. 8 | 9 | Preamble 10 | 11 | The licenses for most software are designed to take away your 12 | freedom to share and change it. By contrast, the GNU General Public 13 | License is intended to guarantee your freedom to share and change free 14 | software--to make sure the software is free for all its users. This 15 | General Public License applies to most of the Free Software 16 | Foundation's software and to any other program whose authors commit to 17 | using it. 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It is safest 289 | to attach them to the start of each source file to most effectively 290 | convey the exclusion of warranty; and each file should have at least 291 | the "copyright" line and a pointer to where the full notice is found. 292 | 293 | 294 | Copyright (C) 295 | 296 | This program is free software; you can redistribute it and/or modify 297 | it under the terms of the GNU General Public License as published by 298 | the Free Software Foundation; either version 2 of the License, or 299 | (at your option) any later version. 300 | 301 | This program is distributed in the hope that it will be useful, 302 | but WITHOUT ANY WARRANTY; without even the implied warranty of 303 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 304 | GNU General Public License for more details. 305 | 306 | You should have received a copy of the GNU General Public License along 307 | with this program; if not, write to the Free Software Foundation, Inc., 308 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 309 | 310 | Also add information on how to contact you by electronic and paper mail. 311 | 312 | If the program is interactive, make it output a short notice like this 313 | when it starts in an interactive mode: 314 | 315 | Gnomovision version 69, Copyright (C) year name of author 316 | Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 317 | This is free software, and you are welcome to redistribute it 318 | under certain conditions; type `show c' for details. 319 | 320 | The hypothetical commands `show w' and `show c' should show the appropriate 321 | parts of the General Public License. Of course, the commands you use may 322 | be called something other than `show w' and `show c'; they could even be 323 | mouse-clicks or menu items--whatever suits your program. 324 | 325 | You should also get your employer (if you work as a programmer) or your 326 | school, if any, to sign a "copyright disclaimer" for the program, if 327 | necessary. Here is a sample; alter the names: 328 | 329 | Yoyodyne, Inc., hereby disclaims all copyright interest in the program 330 | `Gnomovision' (which makes passes at compilers) written by James Hacker. 331 | 332 | , 1 April 1989 333 | Ty Coon, President of Vice 334 | 335 | This General Public License does not permit incorporating your program into 336 | proprietary programs. If your program is a subroutine library, you may 337 | consider it more useful to permit linking proprietary applications with the 338 | library. If this is what you want to do, use the GNU Lesser General 339 | Public License instead of this License. 340 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | [![Latest Stable Version]](https://packagist.org/packages/wikimedia/php-session-serializer) [![License]](https://packagist.org/packages/wikimedia/php-session-serializer) 2 | 3 | php-session-serializer 4 | ====================== 5 | 6 | php-session-serializer is a PHP library that provides methods that work like 7 | PHP's [session_encode][phpencode] and [session_decode][phpdecode] 8 | functions, but don't mess with the `$_SESSION` superglobal. 9 | 10 | It supports the `php`, `php_binary`, and `php_serialize` serialize handlers. 11 | `wddx` is not supported, since it is inferior to `php` and `php_binary`. 12 | 13 | 14 | Usage 15 | ----- 16 | 17 | ```php 18 | use Wikimedia\PhpSessionSerializer; 19 | 20 | // (optional) Send logs to a PSR-3 logger 21 | PhpSessionSerializer::setLogger( $logger ) 22 | 23 | // (optional) Ensure that session.serialize_handler is set to a usable value 24 | PhpSessionSerializer::setSerializeHandler(); 25 | 26 | // Encode session data 27 | $string = PhpSessionSerializer::encode( $array ); 28 | 29 | // Decode session data 30 | $array = PhpSessionSerializer::decode( $string ); 31 | ``` 32 | 33 | Running tests 34 | ------------- 35 | 36 | composer install --prefer-dist 37 | composer test 38 | 39 | 40 | History 41 | ------- 42 | 43 | This library was created to support custom session handler [read][] and 44 | [write][] methods that are more useful than blindly storing the serialized data 45 | that PHP gives to custom handlers. 46 | 47 | 48 | --- 49 | [phpencode]: https://php.net/manual/en/function.session-encode.php 50 | [phpdecode]: https://php.net/manual/en/function.session-decode.php 51 | [read]: https://php.net/manual/en/sessionhandlerinterface.read.php 52 | [write]: https://php.net/manual/en/sessionhandlerinterface.write.php 53 | [Latest Stable Version]: https://poser.pugx.org/wikimedia/php-session-serializer/v/stable.svg 54 | [License]: https://poser.pugx.org/wikimedia/php-session-serializer/license.svg 55 | -------------------------------------------------------------------------------- /formats.md: -------------------------------------------------------------------------------- 1 | PHP session serialization formats 2 | ================================= 3 | 4 | These are the currently available formats in basic PHP. 5 | 6 | In the older formats, you can see the legacy of PHP's old "register random 7 | global variables for the session" mechanism in the fact that they have the 8 | ability to indicate unset-but-present as a distinct value. 9 | 10 | 11 | php 12 | --- 13 | 14 | This is PHP's default format. Set values are encoded as 15 | `{$key}|{$serializedValue}`, while unset values are `{$key}!` and placed at the 16 | end of the string. An attempt to insert unset-but-present in the middle of the 17 | string will append it to the next key (since 5.2.6 or earlier, anyway). 18 | 19 | For example, `foo|i:1;baz|s:6:"string";bar!` encodes session data with 20 | 'foo' = 1, 'baz' = "string", and 'bar' is present but unset. 21 | 22 | Due to these delimiters, keys may not contain pipe (`|`) or bang (`!`) characters. 23 | Attempting to serialize a `$_SESSION` array containing these characters will 24 | fail. 25 | 26 | Keys also may not be numeric. Any numeric entries in `$_SESSION` will be ignored. 27 | 28 | There is no value length or delimiter. 29 | 30 | 31 | php_binary 32 | ---------- 33 | 34 | Keys are encoded as a byte length (up to 127) followed by the indicated number 35 | of bytes. If the variable is unset, the high bit of the length is set. 36 | Otherwise, the serialized value follows immediately after the end of the key. 37 | 38 | Depending on the version of PHP, an unset-but-present might ignore the key, 39 | might set the key to null, or might stop processing the rest of the string 40 | entirely. This library takes the first option. 41 | 42 | For example, `\x03fooi:1;\x03bazs:6:"string";\x83bar` encodes session data with 43 | 'foo' = 1, 'baz' = "string", and 'bar' is present but unset. 44 | 45 | Due to the size of the length field, keys may not be more than 127 bytes long. 46 | Entries in `$_SESSION` with longer keys are ignored. 47 | 48 | Keys also may not be numeric. Any numeric entries in `$_SESSION` will be ignored. 49 | 50 | There is no value length or delimiter. 51 | 52 | 53 | php_serialize 54 | ------------- 55 | 56 | This is the most reliable format, added in PHP 5.5.4. The format is just 57 | `$_SESSION` passed to the standard [`serialize()`][serialize] function. It does 58 | not have the ability to indicate unset-but-present. 59 | 60 | For example, `a:2:{s:3:"foo";i:1;s:3:"baz";s:6:"string";}` encodes session data 61 | with 'foo' = 1 and 'baz' = "string". 62 | 63 | Unlike other formats, numeric keys are allowed and are stored correctly. 64 | 65 | When decoding the session, PHP does not check that the encoded string encodes 66 | an array, and will happily set `$_SESSION` to other types. It will refuse to 67 | re-serialize such a `$_SESSION`, however. 68 | 69 | 70 | wddx 71 | ---- 72 | 73 | When WDDX support is compiled into PHP, the WDDX format may be used to store 74 | session data. This format, however, cannot represent the full range of PHP data 75 | types (e.g. `INF`, `NAN`, data structures containing references) and so is not 76 | likely to be particularly useful unless you're trying to share saved session 77 | data with code in some other language that has WDDX support. 78 | 79 | 80 | 81 | --- 82 | [serialize]: https://php.net/manual/en/function.serialize.php 83 | -------------------------------------------------------------------------------- /src/PhpSessionSerializer.php: -------------------------------------------------------------------------------- 1 | 6 | * 7 | * This program is free software; you can redistribute it and/or modify 8 | * it under the terms of the GNU General Public License as published by 9 | * the Free Software Foundation; either version 2 of the License, or 10 | * (at your option) any later version. 11 | * 12 | * This program is distributed in the hope that it will be useful, 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | * GNU General Public License for more details. 16 | * 17 | * You should have received a copy of the GNU General Public License along 18 | * with this program; if not, write to the Free Software Foundation, Inc., 19 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 20 | * http://www.gnu.org/copyleft/gpl.html 21 | * 22 | * @file 23 | * @author Brad Jorsch 24 | */ 25 | 26 | namespace Wikimedia; 27 | 28 | use DomainException; 29 | use Exception; 30 | use InvalidArgumentException; 31 | use Psr\Log\LoggerInterface; 32 | use UnexpectedValueException; 33 | 34 | /** 35 | * Provides for encoding and decoding session arrays to PHP's serialization 36 | * formats. 37 | * 38 | * Supported formats are: 39 | * - php 40 | * - php_binary 41 | * - php_serialize 42 | * 43 | * WDDX is not supported, since it breaks on all sorts of things. 44 | */ 45 | class PhpSessionSerializer { 46 | /** @var LoggerInterface */ 47 | protected static $logger; 48 | 49 | /** 50 | * Set the logger to which to log 51 | * @param LoggerInterface $logger The logger 52 | */ 53 | public static function setLogger( LoggerInterface $logger ) { 54 | self::$logger = $logger; 55 | } 56 | 57 | /** 58 | * Try to set session.serialize_handler to a supported format 59 | * 60 | * This may change the format even if the current format is also supported. 61 | * 62 | * @return string Format set 63 | * @throws DomainException 64 | */ 65 | public static function setSerializeHandler() { 66 | $formats = [ 67 | 'php_serialize', 68 | 'php', 69 | 'php_binary', 70 | ]; 71 | 72 | // First, try php_serialize since that's the only one that doesn't suck in some way. 73 | // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged 74 | @ini_set( 'session.serialize_handler', 'php_serialize' ); 75 | if ( ini_get( 'session.serialize_handler' ) === 'php_serialize' ) { 76 | return 'php_serialize'; 77 | } 78 | 79 | // Next, just use the current format if it's supported. 80 | $format = ini_get( 'session.serialize_handler' ); 81 | if ( in_array( $format, $formats, true ) ) { 82 | return $format; 83 | } 84 | 85 | // Last chance, see if any of our supported formats are accepted. 86 | foreach ( $formats as $format ) { 87 | // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged 88 | @ini_set( 'session.serialize_handler', $format ); 89 | if ( ini_get( 'session.serialize_handler' ) === $format ) { 90 | return $format; 91 | } 92 | } 93 | 94 | throw new DomainException( 95 | 'Failed to set serialize handler to a supported format.' . 96 | ' Supported formats are: ' . implode( ', ', $formats ) . '.' 97 | ); 98 | } 99 | 100 | /** 101 | * Encode a session array to a string, using the format in session.serialize_handler 102 | * @param array $data Session data 103 | * @return string|null Encoded string, or null on failure 104 | * @throws DomainException 105 | */ 106 | public static function encode( array $data ) { 107 | $format = ini_get( 'session.serialize_handler' ); 108 | if ( !is_string( $format ) ) { 109 | throw new UnexpectedValueException( 110 | 'Could not fetch the value of session.serialize_handler' 111 | ); 112 | } 113 | switch ( $format ) { 114 | case 'php': 115 | return self::encodePhp( $data ); 116 | 117 | case 'php_binary': 118 | return self::encodePhpBinary( $data ); 119 | 120 | case 'php_serialize': 121 | return self::encodePhpSerialize( $data ); 122 | 123 | default: 124 | throw new DomainException( "Unsupported format \"$format\"" ); 125 | } 126 | } 127 | 128 | /** 129 | * Decode a session string to an array, using the format in session.serialize_handler 130 | * @param string $data Session data. Use the same caution in passing 131 | * user-controlled data here that you would to PHP's unserialize function. 132 | * @return array|null Data, or null on failure 133 | * @throws DomainException 134 | * @throws InvalidArgumentException 135 | */ 136 | public static function decode( $data ) { 137 | if ( !is_string( $data ) ) { 138 | throw new InvalidArgumentException( '$data must be a string' ); 139 | } 140 | 141 | $format = ini_get( 'session.serialize_handler' ); 142 | if ( !is_string( $format ) ) { 143 | throw new UnexpectedValueException( 144 | 'Could not fetch the value of session.serialize_handler' 145 | ); 146 | } 147 | switch ( $format ) { 148 | case 'php': 149 | return self::decodePhp( $data ); 150 | 151 | case 'php_binary': 152 | return self::decodePhpBinary( $data ); 153 | 154 | case 'php_serialize': 155 | return self::decodePhpSerialize( $data ); 156 | 157 | default: 158 | throw new DomainException( "Unsupported format \"$format\"" ); 159 | } 160 | } 161 | 162 | /** 163 | * Serialize a value with error logging 164 | * @param mixed $value 165 | * @return string|null 166 | */ 167 | private static function serializeValue( $value ) { 168 | try { 169 | return serialize( $value ); 170 | } catch ( Exception $ex ) { 171 | self::$logger->error( 'Value serialization failed: ' . $ex->getMessage() ); 172 | return null; 173 | } 174 | } 175 | 176 | /** 177 | * Unserialize a value with error logging 178 | * @param string &$string On success, the portion used is removed 179 | * @return array ( bool $success, mixed $value ) 180 | */ 181 | private static function unserializeValue( &$string ) { 182 | $error = null; 183 | set_error_handler( static function ( $errno, $errstr ) use ( &$error ) { 184 | if ( $errno === E_WARNING && strpos( $errstr, 'unserialize(): Extra data starting at offset' ) === 0 ) { 185 | // Since php8.3 unserialize() emits E_WARNING when the input string has unconsumed data. 186 | // Ignore this error 187 | } else { 188 | $error = $errstr; 189 | } 190 | return true; 191 | } ); 192 | $ret = unserialize( $string ); 193 | restore_error_handler(); 194 | 195 | if ( $error !== null ) { 196 | self::$logger->error( 'Value unserialization failed: ' . $error ); 197 | return [ false, null ]; 198 | } 199 | 200 | $serialized = serialize( $ret ); 201 | $l = strlen( $serialized ); 202 | if ( substr( $string, 0, $l ) !== $serialized ) { 203 | self::$logger->error( 204 | 'Value unserialization failed: read value does not match original string' 205 | ); 206 | return [ false, null ]; 207 | } 208 | 209 | $string = substr( $string, $l ); 210 | return [ true, $ret ]; 211 | } 212 | 213 | /** 214 | * Encode a session array to a string in 'php' format 215 | * @note Generally you'll use self::encode() instead of this method. 216 | * @param array $data Session data 217 | * @return string|null Encoded string, or null on failure 218 | */ 219 | public static function encodePhp( array $data ) { 220 | $ret = ''; 221 | foreach ( $data as $key => $value ) { 222 | // @phan-suppress-next-line PhanTypeMismatchArgumentInternal 223 | if ( strcmp( $key, intval( $key ) ) === 0 ) { 224 | self::$logger->warning( "Ignoring unsupported integer key \"$key\"" ); 225 | continue; 226 | } 227 | if ( strcspn( $key, '|!' ) !== strlen( $key ) ) { 228 | self::$logger->error( "Serialization failed: Key with unsupported characters \"$key\"" ); 229 | return null; 230 | } 231 | $v = self::serializeValue( $value ); 232 | if ( $v === null ) { 233 | return null; 234 | } 235 | $ret .= "$key|$v"; 236 | } 237 | return $ret; 238 | } 239 | 240 | /** 241 | * Decode a session string in 'php' format to an array 242 | * @note Generally you'll use self::decode() instead of this method. 243 | * @param string $data Session data. Use the same caution in passing 244 | * user-controlled data here that you would to PHP's unserialize function. 245 | * @return array|null Data, or null on failure 246 | * @throws InvalidArgumentException 247 | */ 248 | public static function decodePhp( $data ) { 249 | if ( !is_string( $data ) ) { 250 | throw new InvalidArgumentException( '$data must be a string' ); 251 | } 252 | 253 | $ret = []; 254 | while ( $data !== '' && $data !== false ) { 255 | $i = strpos( $data, '|' ); 256 | if ( $i === false ) { 257 | if ( substr( $data, -1 ) !== '!' ) { 258 | self::$logger->warning( 'Ignoring garbage at end of string' ); 259 | } 260 | break; 261 | } 262 | 263 | $key = substr( $data, 0, $i ); 264 | $data = substr( $data, $i + 1 ); 265 | 266 | if ( strpos( $key, '!' ) !== false ) { 267 | self::$logger->warning( "Decoding found a key with unsupported characters: \"$key\"" ); 268 | } 269 | 270 | if ( $data === '' || $data === false ) { 271 | self::$logger->error( 'Unserialize failed: unexpected end of string' ); 272 | return null; 273 | } 274 | 275 | [ $ok, $value ] = self::unserializeValue( $data ); 276 | if ( !$ok ) { 277 | return null; 278 | } 279 | $ret[$key] = $value; 280 | } 281 | return $ret; 282 | } 283 | 284 | /** 285 | * Encode a session array to a string in 'php_binary' format 286 | * @note Generally you'll use self::encode() instead of this method. 287 | * @param array $data Session data 288 | * @return string|null Encoded string, or null on failure 289 | */ 290 | public static function encodePhpBinary( array $data ) { 291 | $ret = ''; 292 | foreach ( $data as $key => $value ) { 293 | // @phan-suppress-next-line PhanTypeMismatchArgumentInternal 294 | if ( strcmp( $key, intval( $key ) ) === 0 ) { 295 | self::$logger->warning( "Ignoring unsupported integer key \"$key\"" ); 296 | continue; 297 | } 298 | $l = strlen( $key ); 299 | if ( $l > 127 ) { 300 | self::$logger->warning( "Ignoring overlong key \"$key\"" ); 301 | continue; 302 | } 303 | $v = self::serializeValue( $value ); 304 | if ( $v === null ) { 305 | return null; 306 | } 307 | $ret .= chr( $l ) . $key . $v; 308 | } 309 | return $ret; 310 | } 311 | 312 | /** 313 | * Decode a session string in 'php_binary' format to an array 314 | * @note Generally you'll use self::decode() instead of this method. 315 | * @param string $data Session data. Use the same caution in passing 316 | * user-controlled data here that you would to PHP's unserialize function. 317 | * @return array|null Data, or null on failure 318 | * @throws InvalidArgumentException 319 | */ 320 | public static function decodePhpBinary( $data ) { 321 | if ( !is_string( $data ) ) { 322 | throw new InvalidArgumentException( '$data must be a string' ); 323 | } 324 | 325 | $ret = []; 326 | while ( $data !== '' && $data !== false ) { 327 | $l = ord( $data[0] ); 328 | if ( strlen( $data ) < ( $l & 127 ) + 1 ) { 329 | self::$logger->error( 'Unserialize failed: unexpected end of string' ); 330 | return null; 331 | } 332 | 333 | // "undefined" marker 334 | if ( $l > 127 ) { 335 | $data = substr( $data, ( $l & 127 ) + 1 ); 336 | continue; 337 | } 338 | 339 | $key = substr( $data, 1, $l ); 340 | $data = substr( $data, $l + 1 ); 341 | if ( $data === '' || $data === false ) { 342 | self::$logger->error( 'Unserialize failed: unexpected end of string' ); 343 | return null; 344 | } 345 | 346 | [ $ok, $value ] = self::unserializeValue( $data ); 347 | if ( !$ok ) { 348 | return null; 349 | } 350 | $ret[$key] = $value; 351 | } 352 | return $ret; 353 | } 354 | 355 | /** 356 | * Encode a session array to a string in 'php_serialize' format 357 | * @note Generally you'll use self::encode() instead of this method. 358 | * @param array $data Session data 359 | * @return string|null Encoded string, or null on failure 360 | */ 361 | public static function encodePhpSerialize( array $data ) { 362 | try { 363 | return serialize( $data ); 364 | } catch ( Exception $ex ) { 365 | self::$logger->error( 'PHP serialization failed: ' . $ex->getMessage() ); 366 | return null; 367 | } 368 | } 369 | 370 | /** 371 | * Decode a session string in 'php_serialize' format to an array 372 | * @note Generally you'll use self::decode() instead of this method. 373 | * @param string $data Session data. Use the same caution in passing 374 | * user-controlled data here that you would to PHP's unserialize function. 375 | * @return array|null Data, or null on failure 376 | * @throws InvalidArgumentException 377 | */ 378 | public static function decodePhpSerialize( $data ) { 379 | if ( !is_string( $data ) ) { 380 | throw new InvalidArgumentException( '$data must be a string' ); 381 | } 382 | 383 | $error = null; 384 | set_error_handler( static function ( $errno, $errstr ) use ( &$error ) { 385 | $error = $errstr; 386 | return true; 387 | } ); 388 | $ret = unserialize( $data ); 389 | restore_error_handler(); 390 | 391 | if ( $error !== null ) { 392 | self::$logger->error( 'PHP unserialization failed: ' . $error ); 393 | return null; 394 | } 395 | 396 | // PHP strangely allows non-arrays to session_decode(), even though 397 | // that breaks $_SESSION. Let's not do that. 398 | if ( !is_array( $ret ) ) { 399 | self::$logger->error( 'PHP unserialization failed (value was not an array)' ); 400 | return null; 401 | } 402 | 403 | return $ret; 404 | } 405 | 406 | } 407 | 408 | PhpSessionSerializer::setLogger( new \Psr\Log\NullLogger() ); // @codeCoverageIgnore 409 | --------------------------------------------------------------------------------